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Iyer SH, Hinman JE, Warren T, Matthews SA, Simeone TA, Simeone KA. Altered ventilatory responses to hypercapnia-hypoxia challenges in a preclinical SUDEP model involve orexin neurons. Neurobiol Dis 2024; 199:106592. [PMID: 38971479 DOI: 10.1016/j.nbd.2024.106592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 06/25/2024] [Accepted: 07/02/2024] [Indexed: 07/08/2024] Open
Abstract
Failure to recover from repeated hypercapnia and hypoxemia (HH) challenges caused by severe GCS and postictal apneas may contribute to sudden unexpected death in epilepsy (SUDEP). Our previous studies found orexinergic dysfunction contributes to respiratory abnormalities in a preclinical model of SUDEP, Kcna1-/- mice. Here, we developed two gas challenges consisting of repeated HH exposures and used whole body plethysmography to determine whether Kcna1-/- mice have detrimental ventilatory responses. Kcna1-/- mice exhibited an elevated ventilatory response to a mild repeated hypercapnia-hypoxia (HH) challenge compared to WT. Moreover, 71% of Kcna1-/- mice failed to survive a severe repeated HH challenge, whereas all WT mice recovered. We next determined whether orexin was involved in these differences. Pretreating Kcna1-/- mice with a dual orexin receptor antagonist rescued the ventilatory response during the mild challenge and all subjects survived the severe challenge. In ex vivo extracellular recordings in the lateral hypothalamus of coronal brain slices, we found reducing pH either inhibits or stimulates putative orexin neurons similar to other chemosensitive neurons; however, a significantly greater percentage of putative orexin neurons from Kcna1-/-mice were stimulated and the magnitude of stimulation was increased resulting in augmentation of the calculated chemosensitivity index relative to WT. Collectively, our data suggest that increased chemosensitive activity of orexin neurons may be pathologic in the Kcna1-/- mouse model of SUDEP, and contribute to elevated ventilatory responses. Our preclinical data suggest that those at high risk for SUDEP may be more sensitive to HH challenges, whether induced by seizures or other means; and the depth and length of the HH exposure could dictate the probability of survival.
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Affiliation(s)
- Shruthi H Iyer
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE 68178, USA
| | - Jillian E Hinman
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE 68178, USA
| | - Ted Warren
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE 68178, USA
| | - Stephanie A Matthews
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE 68178, USA
| | - Timothy A Simeone
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE 68178, USA
| | - Kristina A Simeone
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE 68178, USA.
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Fritz C, Jaeger D, Luo Y, Lardenois E, Badat B, Roquet FE, Rigollot M, Kimmoun A, Tran N'G, Richard JCM, Chouihed T, Levy B. IMPACT OF DIFFERENT VENTILATION STRATEGIES ON GAS EXCHANGES AND CIRCULATION DURING PROLONGED MECHANICAL CARDIO-PULMONARY RESUSCITATION IN A PORCINE MODEL. Shock 2022; 58:119-127. [PMID: 34710880 DOI: 10.1097/shk.0000000000001880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
ABSTRACT Background: Optimal ventilation during cardio-pulmonary resuscitation (CPR) is still controversial. Ventilation is expected to provide sufficient arterial oxygen content and adequate carbon dioxide removal, while minimizing the risk of circulatory impairment. The objective of the present study was to compare three ventilation strategies in a porcine model during mechanical continuous chest compressions (CCC) according to arterial oxygenation and hemodynamic impact. Method: Ventricular fibrillation was induced and followed by five no-flow minutes and thirty low-flow minutes resuscitation with mechanical-CCC without vasopressive drugs administration. Three groups of eight Landras pig were randomized according to the ventilation strategy: 1. Standard nonsynchronized volume-control mode (SD-group); 2. synchronized bilevel pressure-controlled ventilation (CPV-group); 3. continuous insufflation with Boussignac Cardiac-Arrest Device (BC-group). We assessed 1. arterial blood gases, 2. macro hemodynamics, 3. tissular cerebral macro and micro-circulation and 4. airway pressure, minute ventilation at baseline and every 5 minutes during the protocol. Results: Arterial PaO2 level was higher at each measurement time in SD-group (>200 mm Hg) compare to CPV-group and BC-group ( P < 0.01). In BC-group, arterial PaCO2 level was significantly higher (>90mm Hg) than in SD and CPV groups ( P < 0.01). There was no difference between groups concerning hemodynamic parameters, cerebral perfusion and microcirculation. Conclusion: Ventilation modalities in this porcine model of prolonged CPR influence oxygenation and decarboxylation without impairing circulation and cerebral perfusion. Synchronized bi-level pressure-controlled ventilation' use avoid hyperoxia and was as efficient as asynchronized volume ventilation to maintain alveolar ventilation and systemic perfusion during prolonged CPR.
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Abstract
Carbon dioxide is a common gas in the air which has been widely used in medical treatment. A carbon dioxide molecule consists of two oxygen atoms and one carbon atom through a covalent bond. In the body, carbon dioxide reacts with water to produce carbonic acid. In healthy people, carbon dioxide is maintained within a narrow range (35–45 mmHg) by physiological mechanisms. The role of hypocapnia (partial pressure of carbon dioxide < 35 mmHg) and hypercapnia (partial pressure of carbon dioxide > 45 mmHg) in the nervous system is intricate. Past researches mainly focus on the effect of hypocapnia to nerve protection. Nevertheless, Hypercapnia seems to play an important role in neuroprotection. The mechanisms of hypocapnia and hypercapnia in the nervous system deserve our attention. The purpose of this review is to summarize the effect of hypocapnia and hypercapnia in stroke and traumatic brain injury.
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Affiliation(s)
- Ru-Ming Deng
- Department of Neurosurgery, the First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China
| | - Yong-Chun Liu
- Department of Neurosurgery, the First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China
| | - Jin-Quan Li
- Department of Neurosurgery, the First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China
| | - Jian-Guo Xu
- Department of Neurosurgery, the First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China
| | - Gang Chen
- Department of Neurosurgery, the First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China
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Giannakis S, Ruhfus M, Markus M, Stein A, Hoehn T, Felderhoff-Mueser U, Sabir H. Mechanical Ventilation, Partial Pressure of Carbon Dioxide, Increased Fraction of Inspired Oxygen and the Increased Risk for Adverse Short-Term Outcomes in Cooled Asphyxiated Newborns. CHILDREN-BASEL 2021; 8:children8060430. [PMID: 34063852 PMCID: PMC8224013 DOI: 10.3390/children8060430] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 05/04/2021] [Accepted: 05/18/2021] [Indexed: 11/26/2022]
Abstract
Neonates treated with therapeutic hypothermia (TH) following perinatal asphyxia (PA) suffer a considerable rate of disability and mortality. Several risk factors associated with adverse outcomes have been identified. Mechanical ventilation might increase the risk for hyperoxia and hypocapnia in cooled newborns. We carried out a retrospective study in 71 asphyxiated cooled newborns. We analyzed the association of ventilation status and adverse short-term outcomes and investigated the effect of the former on pCO2 and oxygen delivery before, during and after TH. Death, abnormal findings on magnetic resonance imaging, and pathological amplitude-integrated electroencephalography traces were used to define short-term outcomes. The need for mechanical ventilation was significantly higher in the newborns with adverse outcomes (38% vs. 5.6%, p = 0.001). Compared to spontaneously breathing neonates, intubated newborns suffered from significantly more severe asphyxia, had significantly lower levels of mean minimum pCO2 over the first 6 and 72 h of life (HOL) (p = 0.03 and p = 0.01, respectively) and increased supply of inspired oxygen, which was, in turn, significantly higher in the newborns with adverse outcomes (p < 0.01). Intubated newborns with adverse short-term outcomes had lower levels of pCO2 over the first 36 HOL. In conclusion, need for mechanical ventilation was significantly higher in newborns with more severe asphyxia. In ventilated newborns, level of encephalopathy, lower pCO2 levels, and increased oxygen supplementation were significantly higher in the adverse short-term outcomes group. Ventilatory parameters need to be carefully monitored in cooled asphyxiated newborns.
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Affiliation(s)
- Stamatios Giannakis
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, Faculty of Medicine, University Children’s Hospital, Heinrich-Heine-University Duesseldorf, 40225 Düsseldorf, Germany; (S.G.); (M.M.); (T.H.)
| | - Maria Ruhfus
- Department of Pediatrics I/Neonatology, University Hospital Essen, University Duisburg Essen, 45147 Essen, Germany; (M.R.); (A.S.); (U.F.-M.)
| | - Mona Markus
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, Faculty of Medicine, University Children’s Hospital, Heinrich-Heine-University Duesseldorf, 40225 Düsseldorf, Germany; (S.G.); (M.M.); (T.H.)
| | - Anja Stein
- Department of Pediatrics I/Neonatology, University Hospital Essen, University Duisburg Essen, 45147 Essen, Germany; (M.R.); (A.S.); (U.F.-M.)
| | - Thomas Hoehn
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, Faculty of Medicine, University Children’s Hospital, Heinrich-Heine-University Duesseldorf, 40225 Düsseldorf, Germany; (S.G.); (M.M.); (T.H.)
| | - Ursula Felderhoff-Mueser
- Department of Pediatrics I/Neonatology, University Hospital Essen, University Duisburg Essen, 45147 Essen, Germany; (M.R.); (A.S.); (U.F.-M.)
| | - Hemmen Sabir
- Department of Pediatrics I/Neonatology, University Hospital Essen, University Duisburg Essen, 45147 Essen, Germany; (M.R.); (A.S.); (U.F.-M.)
- Department of Neonatology and Pediatric Intensive Care, Children’s Hospital University of Bonn, 53127 Bonn, Germany
- German Centre for Neurodegenerative Diseases (DZNE), 53127 Bonn, Germany
- Correspondence:
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Kovács V, Remzső G, Tóth-Szűki V, Varga V, Németh J, Domoki F. Inhaled H 2 or CO 2 Do Not Augment the Neuroprotective Effect of Therapeutic Hypothermia in a Severe Neonatal Hypoxic-Ischemic Encephalopathy Piglet Model. Int J Mol Sci 2020; 21:E6801. [PMID: 32948011 PMCID: PMC7555370 DOI: 10.3390/ijms21186801] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 09/09/2020] [Accepted: 09/14/2020] [Indexed: 12/24/2022] Open
Abstract
Hypoxic-ischemic encephalopathy (HIE) is still a major cause of neonatal death and disability as therapeutic hypothermia (TH) alone cannot afford sufficient neuroprotection. The present study investigated whether ventilation with molecular hydrogen (2.1% H2) or graded restoration of normocapnia with CO2 for 4 h after asphyxia would augment the neuroprotective effect of TH in a subacute (48 h) HIE piglet model. Piglets were randomized to untreated naïve, control-normothermia, asphyxia-normothermia (20-min 4%O2-20%CO2 ventilation; Tcore = 38.5 °C), asphyxia-hypothermia (A-HT, Tcore = 33.5 °C, 2-36 h post-asphyxia), A-HT + H2, or A-HT + CO2 treatment groups. Asphyxia elicited severe hypoxia (pO2 = 19 ± 5 mmHg) and mixed acidosis (pH = 6.79 ± 0.10). HIE development was confirmed by altered cerebral electrical activity and neuropathology. TH was significantly neuroprotective in the caudate nucleus but demonstrated virtually no such effect in the hippocampus. The mRNA levels of apoptosis-inducing factor and caspase-3 showed a ~10-fold increase in the A-HT group compared to naïve animals in the hippocampus but not in the caudate nucleus coinciding with the region-specific neuroprotective effect of TH. H2 or CO2 did not augment TH-induced neuroprotection in any brain areas; rather, CO2 even abolished the neuroprotective effect of TH in the caudate nucleus. In conclusion, the present findings do not support the use of these medical gases to supplement TH in HIE management.
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MESH Headings
- Acidosis/blood
- Acidosis/etiology
- Acidosis/prevention & control
- Administration, Inhalation
- Animals
- Animals, Newborn
- Apoptosis Inducing Factor/biosynthesis
- Apoptosis Inducing Factor/genetics
- Asphyxia Neonatorum/complications
- Asphyxia Neonatorum/drug therapy
- Asphyxia Neonatorum/therapy
- Brain Damage, Chronic/etiology
- Brain Damage, Chronic/prevention & control
- Brain-Derived Neurotrophic Factor/biosynthesis
- Brain-Derived Neurotrophic Factor/genetics
- Carbon Dioxide/administration & dosage
- Carbon Dioxide/therapeutic use
- Carbon Dioxide/toxicity
- Caspase 3/biosynthesis
- Caspase 3/genetics
- Caudate Nucleus/pathology
- Cerebral Cortex/metabolism
- Cerebral Cortex/pathology
- Disease Models, Animal
- Drug Evaluation, Preclinical
- Electroencephalography
- Evoked Potentials, Visual/drug effects
- Gene Expression Regulation/drug effects
- Hippocampus/pathology
- Hydrogen/administration & dosage
- Hydrogen/analysis
- Hydrogen/therapeutic use
- Hypothermia, Induced
- Hypoxia-Ischemia, Brain/complications
- Hypoxia-Ischemia, Brain/drug therapy
- Hypoxia-Ischemia, Brain/pathology
- Hypoxia-Ischemia, Brain/therapy
- Nerve Tissue Proteins/biosynthesis
- Nerve Tissue Proteins/genetics
- Neuroprotection/drug effects
- Neuroprotective Agents/administration & dosage
- Neuroprotective Agents/therapeutic use
- Organ Specificity
- Random Allocation
- Swine
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Affiliation(s)
- Viktória Kovács
- Department of Physiology, University of Szeged Faculty of Medicine, H-6720 Szeged, Hungary; (G.R.); (V.T.-S.); (V.V.); (J.N.); (F.D.)
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6
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Tolaymat Y, Doré S, Griffin HW, Shih S, Edwards ME, Weiss MD. Inhaled Gases for Neuroprotection of Neonates: A Review. Front Pediatr 2019; 7:558. [PMID: 32047729 PMCID: PMC6996209 DOI: 10.3389/fped.2019.00558] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 12/20/2019] [Indexed: 11/30/2022] Open
Abstract
Importance: Hypoxic-ischemic encephalopathy (HIE) is a significant cause of morbidity and mortality in neonates. The incidence of HIE is 1-8 per 1,000 live births in developed countries. Whole-body hypothermia reduces the risk of disability or death, but 7 infants needed to be treated to prevent death or major neurodevelopmental disability. Inhalational gases may be promising synergistic agents due to their rapid onset and easy titratability. Objective: To review current data on different inhaled gases with neuroprotective properties that may serve as adjunct therapies to hypothermia. Evidence review: Literature review was performed using the PubMed database, google scholar, and ClinicalTrials.Gov. Results focused on articles published from January 1, 2005, through December 31, 2017. Articles published earlier than 2005 were included when appropriate for historical perspective. Our review emphasized preclinical and clinical studies relevant to the use of inhaled agents for neuroprotection. Findings: Based on the relevance to our topic, 111 articles were selected pertaining to the incidence of HIE, pathophysiology of HIE, therapeutic hypothermia, and emerging therapies for hypoxic-ischemic encephalopathy in preclinical and clinical settings. Supplemental tables summarizes highly relevant 49 publications that were included in this review. The selected publications emphasize the emergence of promising inhaled gases that may improve neurologic survival and alleviate neurodevelopmental disability when combined with therapeutic hypothermia in the future. Conclusions: Many inhaled agents have neuroprotective properties and could serve as an adjunct therapy to whole-body hypothermia. Inhaled agents are ideal due to their easy administration, titrability, and rapid onset and offset.
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Affiliation(s)
- Youness Tolaymat
- Department of Pediatrics, University of Florida, Gainesville, FL, United States
| | - Sylvain Doré
- Departments of Neurology, Psychiatry, Pharmaceuticals and Neuroscience, University of Florida, Gainesville, FL, United States
| | - Hudson W Griffin
- Department of Anesthesiology, University of Florida, Gainesville, FL, United States
| | - Susana Shih
- Department of Anesthesiology, University of Florida, Gainesville, FL, United States
| | - Mary E Edwards
- Health Science Center Libraries, University of Florida, Gainesville, FL, United States
| | - Michael D Weiss
- Department of Pediatrics, University of Florida, Gainesville, FL, United States
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7
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Does prolonged severe hypercapnia interfere with normal cerebrovascular function in piglets? Pediatr Res 2018; 84:290-295. [PMID: 29907849 PMCID: PMC6185793 DOI: 10.1038/s41390-018-0061-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 04/16/2018] [Accepted: 04/17/2018] [Indexed: 11/21/2022]
Abstract
BACKGROUND Hypercapnia causes cerebral vasodilation and increased cerebral blood flow (CBF). During prolonged hypercapnia it is unknown whether cerebral vasodilation persists and whether cerebrovascular function is preserved. We investigated the effects of prolonged severe hypercapnia on pial arteriolar diameters (PAD) and cerebrovascular reactivity to vasodilators and vasoconstrictors. METHODS Piglets were anesthetized, intubated and ventilated. Closed cranial windows were implanted to measure PAD. Changes in PAD were documented during hypercapnia (PaCO2 75-80 mm Hg). Cerebrovascular reactivity was documented during normocapnia and at 30, 60, and 120 min of hypercapnia. RESULTS Cerebral vasodilation to hypercapnia was sustained over 120 min. Cerebrovascular responses to vasodilators and vasoconstrictors were preserved during hypercapnia. During hypercapnia, vasodilatory responses to second vasodilators were similar to normocapnia, while exposure to vasoconstrictors caused significant vasoconstriction. CONCLUSIONS Prolonged severe hypercapnia causes sustained vasodilation of pial arteriolar diameters indicative of hyperperfusion. During hypercapnia, cerebral vascular responses to vasodilators and vasoconstrictors were preserved, suggesting that cerebral vascular function remained intact. Of note, cerebral vessels during hypercapnia were capable of further dilation when exposed to additional cerebral vasodilators and, significant vasoconstriction when exposed to vasoconstrictors. Extrapolating these findings to infants, we suggest that severe hypercapnia should be avoided, because it could cause/increase cerebrovascular injury.
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Lopez Laporte MA, Wang H, Sanon PN, Barbosa Vargas S, Maluorni J, Rampakakis E, Wintermark P. Association between hypocapnia and ventilation during the first days of life and brain injury in asphyxiated newborns treated with hypothermia. J Matern Fetal Neonatal Med 2017; 32:1312-1320. [DOI: 10.1080/14767058.2017.1404980] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Maria Agustina Lopez Laporte
- Department of Pediatrics, Division of Newborn Medicine, Montreal Children’s Hospital, McGill University, Montreal, Canada
| | - Hui Wang
- Department of Pediatrics, Division of Newborn Medicine, Montreal Children’s Hospital, McGill University, Montreal, Canada
| | - Priscille-Nice Sanon
- Department of Pediatrics, Division of Newborn Medicine, Montreal Children’s Hospital, McGill University, Montreal, Canada
| | - Stephanie Barbosa Vargas
- Department of Pediatrics, Division of Newborn Medicine, Montreal Children’s Hospital, McGill University, Montreal, Canada
| | - Julie Maluorni
- Department of Pediatrics, Division of Newborn Medicine, Montreal Children’s Hospital, McGill University, Montreal, Canada
| | | | - Pia Wintermark
- Department of Pediatrics, Division of Newborn Medicine, Montreal Children’s Hospital, McGill University, Montreal, Canada
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9
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Fuller BM, Mohr NM, Drewry AM, Ferguson IT, Trzeciak S, Kollef MH, Roberts BW. Partial pressure of arterial carbon dioxide and survival to hospital discharge among patients requiring acute mechanical ventilation: A cohort study. J Crit Care 2017; 41:29-35. [PMID: 28472700 PMCID: PMC5633513 DOI: 10.1016/j.jcrc.2017.04.033] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 04/18/2017] [Accepted: 04/21/2017] [Indexed: 10/19/2022]
Abstract
PURPOSE To describe the prevalence of hypocapnia and hypercapnia during the earliest period of mechanical ventilation, and determine the association between PaCO2 and mortality. MATERIALS AND METHODS A cohort study using an emergency department registry of mechanically ventilated patients. PaCO2 was categorized: hypocapnia (<35mmHg), normocapnia (35-45mmHg), and hypercapnia (>45mmHg). The primary outcome was survival to hospital discharge. RESULTS A total of 1,491 patients were included. Hypocapnia occurred in 375 (25%) patients and hypercapnia in 569 (38%). Hypercapnia (85%) had higher survival rate compared to normocapnia (74%) and hypocapnia (66%), P<0.001. PaCO2 was an independent predictor of survival to hospital discharge [hypocapnia (aOR 0.65 (95% confidence interval [CI] 0.48-0.89), normocapnia (reference category), hypercapnia (aOR 1.83 (95% CI 1.32-2.54)]. Over ascending ranges of PaCO2, there was a linear trend of increasing survival up to a PaCO2 range of 66-75mmHg, which had the strongest survival association, aOR 3.18 (95% CI 1.35-7.50). CONCLUSIONS Hypocapnia and hypercapnia occurred frequently after initiation of mechanical ventilation. Higher PaCO2 levels were associated with increased survival. These data provide rationale for a trial examining the optimal PaCO2 in the critically ill.
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Affiliation(s)
- Brian M Fuller
- Departments of Emergency Medicine and Anesthesiology, Division of Critical Care Medicine, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, United States.
| | - Nicholas M Mohr
- Departments of Emergency Medicine and Anesthesiology, Division of Critical Care Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, 200 Hawkins Drive, 1008 RCP, Iowa City, IA 52242, United States.
| | - Anne M Drewry
- Department of Anesthesiology, Division of Critical Care Medicine, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, United States.
| | - Ian T Ferguson
- School of Medicine and Medical Science, University College Dublin, Dublin 4, Ireland.
| | - Stephen Trzeciak
- Departments of Medicine and Emergency Medicine, Division of Critical Care Medicine, Cooper University Hospital, One Cooper Plaza, K152, Camden, NJ 08103, United States.
| | - Marin H Kollef
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, United States.
| | - Brian W Roberts
- Department of Emergency Medicine, Cooper University Hospital, One Cooper Plaza, K152, Camden, NJ 08103, United States.
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10
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Wang P, Li L, Zhang Z, Kan Q, Gao F, Chen S. Time-dependent activity of Na+/H+ exchanger isoform 1 and homeostasis of intracellular pH in astrocytes exposed to CoCl2 treatment. Mol Med Rep 2016; 13:4443-50. [PMID: 27035646 DOI: 10.3892/mmr.2016.5067] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 02/11/2016] [Indexed: 11/06/2022] Open
Abstract
Hypoxia causes injury to the central nervous system during stroke and has significant effects on pH homeostasis. Na+/H+ exchanger isoform 1 (NHE1) is important in the mechanisms of hypoxia and intracellular pH (pHi) homeostasis. As a well-established hypoxia-mimetic agent, CoCl2 stabilizes and increases the expression of hypoxia inducible factor‑1α (HIF-1α), which regulates several genes involved in pH balance, including NHE1. However, it is not fully understood whether NHE1 is activated in astrocytes under CoCl2 treatment. In the current study, pHi and NHE activity were analyzed using the pHi‑sensitive dye BCECF‑AM. Using cariporide (an NHE1‑specific inhibitor) and EIPA (an NHE nonspecific inhibitor), the current study demonstrated that it was NHE1, not the other NHE isoforms, that was important in regulating pHi homeostasis in astrocytes during CoCl2 treatment. Additionally, the present study observed that, during the early period of CoCl2 treatment (the first 2 h), NHE1 activity and pHi dropped immediately, and NHE1 mRNA expression was reduced compared with control levels, whereas expression levels of the NHE1 protein had not yet changed. In the later period of CoCl2 treatment, NHE1 activity and pHi significantly increased compared with the control levels, as did the mRNA and protein expression levels of NHE1. Furthermore, the cell viability and injury of astrocytes was not changed during the initial 8 h of CoCl2 treatment; their deterioration was associated with the higher levels of pHi and NHE1 activity. The current study concluded that NHE1 activity and pHi homeostasis are regulated by CoCl2 treatment in a time-dependent manner in astrocytes, and may be responsible for the changes in cell viability and injury observed under hypoxia-mimetic conditions induced by CoCl2 treatment.
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Affiliation(s)
- Peng Wang
- Department of Basic Medicine, Nursing College, Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Ling Li
- Department of Palliative and Hospice Care, The Ninth People's Hospital of Zhengzhou, Zhengzhou, Henan 450053, P.R. China
| | - Zhenxiang Zhang
- Department of Basic Medicine, Nursing College, Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Quancheng Kan
- Clinical Pharmacology Base, Department of Infectious Disease, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Feng Gao
- Department of Neuroimmunology, Henan Academy of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Suyan Chen
- Department of Basic Medicine, Nursing College, Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
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Yang W, Yue Z, Cui X, Guo Y, Zhang L, Zhou H, Li W. Comparison of the effects of moderate and severe hypercapnic acidosis on ventilation-induced lung injury. BMC Anesthesiol 2015; 15:67. [PMID: 25924944 PMCID: PMC4443663 DOI: 10.1186/s12871-015-0050-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 04/22/2015] [Indexed: 01/12/2023] Open
Abstract
Background We have proved that hypercapnic acidosis (a PaCO2 of 80-100 mmHg) protects against ventilator-induced lung injury in rats. However, there remains uncertainty regarding the appropriate target PaCO2 or if greater CO2 “doses” (PaCO2 > 100 mmHg) demonstrate this effect. We wished to determine whether severe acute hypercapnic acidosis can reduce stretch-induced injury, as well as the role of nuclear factor-κB (NF-κB) in the effects of acute hypercapnic acidosis. Methods Fifty-four rats were ventilated for 4 hours with a pressure-controlled ventilation mode set at a peak inspiratory pressure (PIP) of 30 cmH2O. A gas mixture of carbon dioxide with oxygen (FiCO2 = 4-5%, FiCO2 = 11-12% or FiCO2 = 16-17%; FiO2 = 0.7; balance N2) was immediately administered to maintain the target PaCO2 in the NC (a PaCO2 of 35-45 mmHg), MHA (a PaCO2 of 80-100 mmHg) and SHA (a PaCO2 of 130-150 mmHg) groups. Nine normal or non-ventilated rats served as controls. The hemodynamics, gas exchange and inflammatory parameters were measured. The role of NF-κB pathway in hypercapnic acidosis-mediated protection from high-pressure stretch injury was then determined. Results In the NC group, high-pressure ventilation resulted in a decrease in PaO2/FiO2 from 415.6 (37.1) mmHg to 179.1 (23.5) mmHg (p < 0.001), but improved by MHA (379.9 ± 34.5 mmHg) and SHA (298.6 ± 35.3 mmHg). The lung injury score in the SHA group (7.8 ± 1.6) was lower than the NC group (11.8 ± 2.3, P < 0.05) but was higher than the MHA group (4.4 ± 1.3, P < 0.05). Compared with the NC group, after 4 h of high pressure ventilation, the MHA and SHA groups had decreases in MPO activity of 67% and 33%, respectively, and also declined the levels of TNF-α (58% versus 72%) and MIP-2 (76% versus 60%) in the BALF. Additionally, both hypercapnic acidosis groups reduced stretch–induced NF-κB activation (p < 0.05) and significantly decreased lung ICAM-1 expression (p < 0.05). Conclusions Moderate hypercapnic acidosis (PaCO2 maintained at 80-100 mmHg) has a greater protective effect on high-pressure ventilation-induced inflammatory injury. The potential mechanisms may involve alterations in NF-κB activity.
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Affiliation(s)
- Wanchao Yang
- Department of Anesthesiology, Second Affiliated Hospital of Harbin Medical University; Anesthesiology Key Laboratory, Harbin Medical University, Harbin, 150086, China. .,Education Department of Heilongjiang Province, Anesthesiology Key Laboratory, Harbin Medical University, Harbin, Heilongjiang Province, China.
| | - Ziyong Yue
- Department of Anesthesiology, Second Affiliated Hospital of Harbin Medical University; Anesthesiology Key Laboratory, Harbin Medical University, Harbin, 150086, China. .,Education Department of Heilongjiang Province, Anesthesiology Key Laboratory, Harbin Medical University, Harbin, Heilongjiang Province, China.
| | - Xiaoguang Cui
- Department of Anesthesiology, Second Affiliated Hospital of Harbin Medical University; Anesthesiology Key Laboratory, Harbin Medical University, Harbin, 150086, China. .,Education Department of Heilongjiang Province, Anesthesiology Key Laboratory, Harbin Medical University, Harbin, Heilongjiang Province, China.
| | - Yueping Guo
- Department of Anesthesiology, Second Affiliated Hospital of Harbin Medical University; Anesthesiology Key Laboratory, Harbin Medical University, Harbin, 150086, China. .,Education Department of Heilongjiang Province, Anesthesiology Key Laboratory, Harbin Medical University, Harbin, Heilongjiang Province, China.
| | - Lili Zhang
- Department of Anesthesiology, Second Affiliated Hospital of Harbin Medical University; Anesthesiology Key Laboratory, Harbin Medical University, Harbin, 150086, China. .,Education Department of Heilongjiang Province, Anesthesiology Key Laboratory, Harbin Medical University, Harbin, Heilongjiang Province, China.
| | - Huacheng Zhou
- Department of Anesthesiology, Second Affiliated Hospital of Harbin Medical University; Anesthesiology Key Laboratory, Harbin Medical University, Harbin, 150086, China. .,Education Department of Heilongjiang Province, Anesthesiology Key Laboratory, Harbin Medical University, Harbin, Heilongjiang Province, China.
| | - Wenzhi Li
- Department of Anesthesiology, Second Affiliated Hospital of Harbin Medical University; Anesthesiology Key Laboratory, Harbin Medical University, Harbin, 150086, China.
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Alexandre F, Heraud N, Varray A. Is nocturnal desaturation a trigger for neuronal damage in chronic obstructive pulmonary disease? Med Hypotheses 2015; 84:25-30. [DOI: 10.1016/j.mehy.2014.11.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Revised: 11/03/2014] [Accepted: 11/09/2014] [Indexed: 01/26/2023]
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Deng J, Lei C, Chen Y, Fang Z, Yang Q, Zhang H, Cai M, Shi L, Dong H, Xiong L. Neuroprotective gases – Fantasy or reality for clinical use? Prog Neurobiol 2014; 115:210-45. [DOI: 10.1016/j.pneurobio.2014.01.001] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 01/03/2014] [Accepted: 01/03/2014] [Indexed: 12/17/2022]
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Uria-Avellanal C, Robertson NJ. Na⁺/H⁺ exchangers and intracellular pH in perinatal brain injury. Transl Stroke Res 2014; 5:79-98. [PMID: 24452957 PMCID: PMC3913853 DOI: 10.1007/s12975-013-0322-x] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Revised: 12/23/2013] [Accepted: 12/30/2013] [Indexed: 12/12/2022]
Abstract
Encephalopathy consequent on perinatal hypoxia–ischemia occurs in 1–3 per 1,000 term births in the UK and frequently leads to serious and tragic consequences that devastate lives and families, with huge financial burdens for society. Although the recent introduction of cooling represents a significant advance, only 40 % survive with normal neurodevelopmental function. There is thus a significant unmet need for novel, safe, and effective therapies to optimize brain protection following brain injury around birth. The Na+/H+ exchanger (NHE) is a membrane protein present in many mammalian cell types. It is involved in regulating intracellular pH and cell volume. NHE1 is the most abundant isoform in the central nervous system and plays a role in cerebral damage after hypoxia–ischemia. Excessive NHE activation during hypoxia–ischemia leads to intracellular Na+ overload, which subsequently promotes Ca2+ entry via reversal of the Na+/Ca2+ exchanger. Increased cytosolic Ca2+ then triggers the neurotoxic cascade. Activation of NHE also leads to rapid normalization of pHi and an alkaline shift in pHi. This rapid recovery of brain intracellular pH has been termed pH paradox as, rather than causing cells to recover, this rapid return to normal and overshoot to alkaline values is deleterious to cell survival. Brain pHi changes are closely involved in the control of cell death after injury: an alkalosis enhances excitability while a mild acidosis has the opposite effect. We have observed a brain alkalosis in 78 babies with neonatal encephalopathy serially studied using phosphorus-31 magnetic resonance spectroscopy during the first year after birth (151 studies throughout the year including 56 studies of 50 infants during the first 2 weeks after birth). An alkaline brain pHi was associated with severely impaired outcome; the degree of brain alkalosis was related to the severity of brain injury on MRI and brain lactate concentration; and a persistence of an alkaline brain pHi was associated with cerebral atrophy on MRI. Experimental animal models of hypoxia–ischemia show that NHE inhibitors are neuroprotective. Here, we review the published data on brain pHi in neonatal encephalopathy and the experimental studies of NHE inhibition and neuroprotection following hypoxia–ischemia.
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Affiliation(s)
- Cristina Uria-Avellanal
- Neonatology, Institute for Women's Health, University College London, 74 Huntley Street, 4th floor, Room 401, London, WC1E 6AU, UK
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Hwang JH. Optimal Ventilatory Strategies in Preterm Infants: Permissive Hypercapnia. NEONATAL MEDICINE 2014. [DOI: 10.5385/nm.2014.21.2.114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Affiliation(s)
- Jong Hee Hwang
- Department of Pediatrics, Ilsan Paik Hospital, Inje University College of Medicine, Goyang, Korea
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Tao T, Liu Y, Zhang J, Xu Y, Li W, Zhao M. Therapeutic hypercapnia improves functional recovery and attenuates injury via antiapoptotic mechanisms in a rat focal cerebral ischemia/reperfusion model. Brain Res 2013; 1533:52-62. [PMID: 23939225 DOI: 10.1016/j.brainres.2013.08.014] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 08/01/2013] [Accepted: 08/05/2013] [Indexed: 12/13/2022]
Abstract
Recent studies have demonstrated neuroprotective effects of therapeutic hypercapnia for different forms of brain injury. However, few studies have assessed the neuroprotective and neurobehavioral effects of hypercapnia in focal cerebral ischemia, and the underlying mechanisms are still unclear. Here, we investigated the effects of therapeutic hypercapnia in focal cerebral ischemia in the rat middle cerebral artery occlusion/reperfusion (MCAO/R) model. Adult male Sprague Dawley rats were subjected to 90 min of MCAO/R and subsequently exposed to increased carbon dioxide (CO2) levels to maintain arterial blood CO2 tension (PaCO2) between 80 and 100 mmHg for 2h. Neurological deficits were evaluated with the corner test at days 1, 7, 14, and 28. Infarction volume and apoptotic changes were assessed by 2, 3, 7-triphenyltetrazolium chloride (TTC) staining, and terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate-biotin nick end labeling (TUNEL) staining at 24h after reperfusion. Apoptosis-related proteins (Bcl-2, Bax, cytochrome c, and caspase-3) were investigated by western blotting. The results of this study showed that therapeutic hypercapnia significantly reduced infarct volume and improved neurological scores after MCAO/R. Moreover, hypercapnia treatment increased the survival rate at 28 days after reperfusion. The TUNEL-positive neurons in the ipsilateral cortex were significantly decreased in the hypercapnia group. Mitochondrial Bcl-2 and Bax cortical expression levels were significantly higher and lower, respectively, in hypercapnia-treated rats. In addition, hypercapnia treatment decreased cytosolic cytochrome c and cleaved caspase-3 expression and increased cytosolic Bax expression. These findings indicate that therapeutic hypercapnia preserves brain tissue and promotes functional neurological recovery through antiapoptotic mechanisms.
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Affiliation(s)
- Tao Tao
- Department of Anesthesiology, the Second Affiliated Hospital of Harbin Medical University, the Hei Long Jiang Province key Lab of Research on Anesthesiology and Critical Care Medicine, Harbin 150081, China.
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Arterial carbon dioxide tension and outcome in patients admitted to the intensive care unit after cardiac arrest. Resuscitation 2013; 84:927-34. [DOI: 10.1016/j.resuscitation.2013.02.014] [Citation(s) in RCA: 140] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Revised: 01/31/2013] [Accepted: 02/21/2013] [Indexed: 11/23/2022]
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Manole MD, Fink EL. Arterial carbon dioxide tension after cardiac arrest: too little, too much, or just right? Resuscitation 2013; 84:863-4. [PMID: 23643782 PMCID: PMC4482760 DOI: 10.1016/j.resuscitation.2013.04.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 04/17/2013] [Indexed: 11/16/2022]
Affiliation(s)
- Mioara D. Manole
- University of Pittsburgh, Safar Center for Resuscitation Research, 3434 Fifth Avenue,Pittsburgh, PA 15213, United States
| | - Ericka L. Fink
- University of Pittsburgh, Safar Center for Resuscitation Research, 3434 Fifth Avenue,Pittsburgh, PA 15213, United States
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Lara-Celador I, Goñi-de-Cerio F, Alvarez A, Hilario E. Using the endocannabinoid system as a neuroprotective strategy in perinatal hypoxic-ischemic brain injury. Neural Regen Res 2013; 8:731-44. [PMID: 25206720 PMCID: PMC4146074 DOI: 10.3969/j.issn.1673-5374.2013.08.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Accepted: 02/07/2013] [Indexed: 12/30/2022] Open
Abstract
One of the most important causes of brain injury in the neonatal period is a perinatal hypoxic-ischemic event. This devastating condition can lead to long-term neurological deficits or even death. After hypoxic-ischemic brain injury, a variety of specific cellular mechanisms are set in motion, triggering cell damage and finally producing cell death. Effective therapeutic treatments against this phenomenon are still unavailable because of complex molecular mechanisms underlying hypoxic-ischemic brain injury. After a thorough understanding of the mechanism underlying neural plasticity following hypoxic-ischemic brain injury, various neuroprotective therapies have been developed for alleviating brain injury and improving long-term outcomes. Among them, the endocannabinoid system emerges as a natural system of neuroprotection. The endocannabinoid system modulates a wide range of physiological processes in mammals and has demonstrated neuroprotective effects in different paradigms of acute brain injury, acting as a natural neuroprotectant. The aim of this review is to study the use of different therapies to induce long-term therapeutic effects after hypoxic-ischemic brain injury, and analyze the important role of the endocannabinoid system as a new neuroprotective strategy against perinatal hypoxic-ischemic brain injury.
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Affiliation(s)
- I. Lara-Celador
- Department of Cell Biology and Histology, School of Medicine and Dentistry, University of the Basque Country, Leioa 48949, Bizkaia, Spain
| | - F. Goñi-de-Cerio
- GAIKER Technology Centre, Bizkaia Science and Technology Park, Building 202, Zamudio 48170, Bizkaia, Spain
| | - Antonia Alvarez
- Department of Cell Biology and Histology, School of Medicine and Dentistry, University of the Basque Country, Leioa 48949, Bizkaia, Spain
| | - Enrique Hilario
- Department of Cell Biology and Histology, School of Medicine and Dentistry, University of the Basque Country, Leioa 48949, Bizkaia, Spain
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Cerio FGD, Lara-Celador I, Alvarez A, Hilario E. Neuroprotective therapies after perinatal hypoxic-ischemic brain injury. Brain Sci 2013; 3:191-214. [PMID: 24961314 PMCID: PMC4061821 DOI: 10.3390/brainsci3010191] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Revised: 02/13/2013] [Accepted: 02/22/2013] [Indexed: 12/29/2022] Open
Abstract
Hypoxic-ischemic (HI) brain injury is one of the main causes of disabilities in term-born infants. It is the result of a deprivation of oxygen and glucose in the neural tissue. As one of the most important causes of brain damage in the newborn period, the neonatal HI event is a devastating condition that can lead to long-term neurological deficits or even death. The pattern of this injury occurs in two phases, the first one is a primary energy failure related to the HI event and the second phase is an energy failure that takes place some hours later. Injuries that occur in response to these events are often manifested as severe cognitive and motor disturbances over time. Due to difficulties regarding the early diagnosis and treatment of HI injury, there is an increasing need to find effective therapies as new opportunities for the reduction of brain damage and its long term effects. Some of these therapies are focused on prevention of the production of reactive oxygen species, anti-inflammatory effects, anti-apoptotic interventions and in a later stage, the stimulation of neurotrophic properties in the neonatal brain which could be targeted to promote neuronal and oligodendrocyte regeneration.
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Affiliation(s)
- Felipe Goñi de Cerio
- Biotechnology Area, GAIKER Technology Centre, Parque Tecnológico de Zamudio Ed 202, 48170 Zamudio, Vizcaya, Spain.
| | - Idoia Lara-Celador
- Department of Cell Biology and Histology, School of Medicine and Dentistry, University of the Basque Country, 48949 Leioa, Bizkaia, Spain.
| | - Antonia Alvarez
- Department of Cell Biology and Histology, School of Medicine and Dentistry, University of the Basque Country, 48949 Leioa, Bizkaia, Spain.
| | - Enrique Hilario
- Department of Cell Biology and Histology, School of Medicine and Dentistry, University of the Basque Country, 48949 Leioa, Bizkaia, Spain.
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Kendall GS, Hristova M, Zbarsky V, Clements A, Peebles DM, Robertson NJ, Raivich G. Distribution of pH changes in mouse neonatal hypoxic-ischaemic insult. Dev Neurosci 2012; 33:505-18. [PMID: 22343485 DOI: 10.1159/000333850] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2010] [Accepted: 09/26/2011] [Indexed: 11/19/2022] Open
Abstract
We assessed the distribution in brain pH after neonatal hypoxic-ischaemic insult and its correlation with local injury. Postnatal day 7 mice were injected with neutral red and underwent left carotid occlusion and exposure to 8% oxygen. Images captured from the cut surface of snap-frozen brain were used to calculate the pH from the blue-green absorbance ratios. Carotid occlusion alone had no effect, but combined with hypoxia caused rapid, biphasic pH decline, with the first plateau at 15-30 min, and the second at 60-90 min. The ipsilateral dorsal cortex, hippocampus, striatum and thalamus were most affected. Contralateral pH initially showed only 30% of the ipsilateral decline, becoming more acidotic with increasing duration. Systemic blood analysis revealed, compared with hypoxia alone, that combined insult caused a 63% decrease in blood glucose (1.3 ± 0.2 mM), a 2-fold increase in circulating lactate (17.7 ± 2.9 mM), a reduction in CO(2) to 1.9 ± 0.1 kPa and a drop in pH (7.26 ± 0.06). Re-oxygenation resulted in the normalisation of systemic changes, as well as a global alkaline rebound in brain pH at 4-6 h. A topographic comparison of brain injury showed only a partial correlation with pH changes, with the severest injury occurring in the ipsilateral hippocampus and sparing acidic parts of the contralateral cortex.
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Affiliation(s)
- Giles S Kendall
- Centre for Perinatal Brain Protection and Repair, Department of Obstetrics and Gynaecology, University College London, London, UK
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Caron Salloum A, Rakza T, Diependaele JF, Depoortere MH, Delepoulle F, Storme L. [Risk of accumulation of CO₂ in the oxygen chamber in "HOOD" (Experimental study on test bed)]. ANNALES FRANCAISES D'ANESTHESIE ET DE REANIMATION 2011; 30:718-721. [PMID: 21816562 DOI: 10.1016/j.annfar.2011.04.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Accepted: 04/11/2011] [Indexed: 05/31/2023]
Abstract
OBJECTIVES Oxygen hood is largely used to deliver O₂ to newborn infants with respiratory failure in the northern region of France. The oxygen flow is set to obtain the target arterial blood oxygen saturation. Thus, O₂ flow delivers into the hood may be below the recommended gas flow of 6L/min. However, gas flow below 6L/min exposes to CO₂ rebreathing. The aim of this study was to evaluate the effect of various rates of gas flows on the values of partial pressure of CO₂ into the hood. MATERIAL AND METHODS We measured CO₂ and O₂ partial pressure into hoods of two different volumes (4 and 10L) under two experimental bench test conditions. Protocol 1: gas flow was constant at 6L/min, while oxygen fraction varied from 0.21 to 1. Partial pressure of CO₂ and O₂ were recorded. Protocol 2: while O₂ fraction was kept constant, oxygen flow varied from 0.5 to 7L/min (by step of 0.5L/min). Partial pressure of CO₂ and O₂ were recorded. RESULTS Partial pressure of CO₂ increases proportionally to the decrease in the gas flow delivered into the hood, and reached 14 mmHg at gas flow of 0.5L/min. CONCLUSION Risk of CO₂ rebreathing exists as soon as the gas is delivered into the hood at minimal flow rates below 6L/min.
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Affiliation(s)
- A Caron Salloum
- Service de Néonatologie, CH de Dunkerque, 130, avenue Louis-Herbeaux, 59385 Dunkerque cedex 1, France
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Abstract
Infants of birth weight ≤2500 g are termed low birth weight (LBW). These children often have considerable morbidity from prematurity and intra-uterine growth restriction. Additionally, LBW infants have increased risk for cardiac and noncardiac congenital anomalies and may require surgery. Primary rather than palliative surgical repair of cardiac lesions has been preferred in recent years. However, LBW remains a risk factor for increased mortality and morbidity after open-heart surgery (OHS). There is a paucity of information about the anesthetic challenges presented by LBW infants undergoing OHS. This review summarizes the perioperative issues of relevance to anesthesiologists who manage these high-risk patients. Emphasis is placed on management concerns that are unique to LBW infants. Retrospective data from the authors' institution are provided for those aspects of anesthetic care that lack published studies. Successful outcome often requires substantial hospital resources and collaborative multi-disciplinary effort.
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Affiliation(s)
- Glyn D Williams
- Department of Anesthesiology, Stanford University, Lucile Packard Children’s Hospital, Stanford, CA, USA
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Pappas A, Shankaran S, Laptook AR, Langer JC, Bara R, Ehrenkranz RA, Goldberg RN, Das A, Higgins RD, Tyson JE, Walsh MC. Hypocarbia and adverse outcome in neonatal hypoxic-ischemic encephalopathy. J Pediatr 2011; 158:752-758.e1. [PMID: 21146184 PMCID: PMC3229432 DOI: 10.1016/j.jpeds.2010.10.019] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2010] [Revised: 09/10/2010] [Accepted: 10/15/2010] [Indexed: 10/18/2022]
Abstract
OBJECTIVE To evaluate the association between early hypocarbia and 18- to 22-month outcome among neonates with hypoxic-ischemic encephalopathy. STUDY DESIGN Data from the National Institute of Child Health and Human Development Neonatal Research Network randomized, controlled trial of whole-body hypothermia for neonatal hypoxic-ischemic encephalopathy were used for this secondary observational study. Infants (n = 204) had multiple blood gases recorded from birth to 12 hours of study intervention (hypothermia versus intensive care alone). The relationship between hypocarbia and outcome (death/disability at 18 to 22 months) was evaluated by unadjusted and adjusted analyses examining minimum PCO(2) and cumulative exposure to PCO(2) <35 mm Hg. The relationship between cumulative PCO(2) <35 mm Hg (calculated as the difference between 35 mm Hg and the sampled PCO(2) multiplied by the duration of time spent <35 mm Hg) and outcome was evaluated by level of exposure (none-high) using a multiple logistic regression analysis with adjustments for pH, level of encephalopathy, treatment group (± hypothermia), and time to spontaneous respiration and ventilator days; results were expressed as odds ratios and 95% confidence intervals. Alternative models of CO(2) concentration were explored to account for fluctuations in CO(2). RESULTS Both minimum PCO(2) and cumulative PCO(2) <35 mm Hg were associated with poor outcome (P < .05). Moreover, death/disability increased with greater cumulative exposure to PCO(2) <35 mm Hg. CONCLUSIONS Hypocarbia is associated with poor outcome after hypoxic-ischemic encephalopathy.
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Affiliation(s)
- Athina Pappas
- Department of Pediatrics, Wayne State University School of Medicine, Detroit, MI 48201, USA.
| | - Seetha Shankaran
- Department of Pediatrics, Wayne State University School of Medicine, Detroit MI
| | - Abbot R. Laptook
- Department of Pediatrics, Women and Infants’ Hospital, Brown University, Providence RI
| | - John C. Langer
- Statistics and Epidemiology, RTI International, Research Triangle Park, NC
| | - Rebecca Bara
- Department of Pediatrics, Wayne State University School of Medicine, Detroit MI
| | | | | | - Abhik Das
- Statistics and Epidemiology, RTI International, Research Triangle Park, NC
| | - Rosemary D. Higgins
- Pregnancy and Perinatology Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health
| | - Jon E. Tyson
- Department of Pediatrics, University of Texas Medical School at Houston
| | - Michele C. Walsh
- Department of Pediatrics, Rainbow Babies & Children’s Hospital, Case Western Reserve University, Cleveland OH
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Helmy MM, Tolner EA, Vanhatalo S, Voipio J, Kaila K. Brain alkalosis causes birth asphyxia seizures, suggesting therapeutic strategy. Ann Neurol 2011; 69:493-500. [PMID: 21337602 DOI: 10.1002/ana.22223] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2010] [Revised: 07/12/2010] [Accepted: 08/06/2010] [Indexed: 11/09/2022]
Abstract
OBJECTIVE The mechanisms whereby birth asphyxia leads to generation of seizures remain unidentified. To study the possible role of brain pH changes, we used a rodent model that mimics the alterations in systemic CO(2) and O(2) levels during and after intrapartum birth asphyxia. METHODS Neonatal rat pups were exposed for 1 hour to hypercapnia (20% CO(2) in the inhaled gas), hypoxia (9% O(2)), or both (asphyxic conditions). CO(2) levels of 10% and 5% were used for graded restoration of normocapnia. Seizures were characterized behaviorally and utilizing intracranial electroencephalography. Brain pH and oxygen were measured with intracortical microelectrodes, and blood pH, ionized calcium, carbon dioxide, oxygen, and lactate with a clinical device. The impact of the postexposure changes in brain pH on seizure burden was assessed during 2 hours after restoration of normoxia and normocapnia. N-methyl-isobutyl-amiloride, an inhibitor of Na(+) /H(+) exchange, was given intraperitoneally. RESULTS Whereas hypercapnia or hypoxia alone did not result in an appreciable postexposure seizure burden, recovery from asphyxic conditions was followed by a large seizure burden that was tightly paralleled by a rise in brain pH, but no change in brain oxygenation. By graded restoration of normocapnia after asphyxia, the alkaline shift in brain pH and the seizure burden were strongly suppressed. The seizures were virtually blocked by preapplication of N-methyl-isobutyl-amiloride. INTERPRETATION Our data indicate that brain alkalosis after recovery from birth asphyxia plays a key role in the triggering of seizures. We question the current practice of rapid restoration of normocapnia in the immediate postasphyxic period, and suggest a novel therapeutic strategy based on graded restoration of normocapnia.
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Establishing gas exchange and improving oxygenation in the delivery room management of the lung. Adv Neonatal Care 2010; 10:256-60. [PMID: 20838076 DOI: 10.1097/anc.0b013e3181f0836d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
One of the components of promoting good outcomes in high-risk neonates is supporting normal gas exchange while avoiding lung injury. Respiratory care in the first hour following birth plays an important role in stabilizing the infant with respiratory problems. The goal of this article is to review the causes of lung injury that can occur in the first hour and that could be prevented with careful respiratory support.
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Yager JY, Armstrong EA, Black AM. Treatment of the term newborn with brain injury: simplicity as the mother of invention. Pediatr Neurol 2009; 40:237-43. [PMID: 19218037 DOI: 10.1016/j.pediatrneurol.2008.12.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2008] [Accepted: 11/03/2008] [Indexed: 11/28/2022]
Abstract
Neonatal brain injury remains a common cause of developmental disability, despite tremendously enhanced obstetrical and neonatal care. The timing of brain injury occurs throughout gestation, labor, and delivery, providing an evolving form of brain injury and a moving target for therapeutic intervention. Nonetheless, markedly improved methods are available to identify those infants injured at birth, via clinical presentation with neonatal encephalopathy and neuroimaging techniques. Postischemic hypothermia has been shown to be of tremendous clinical promise in several completed and ongoing trials. As part of this approach to the treatment of the newborn, other parameters of physiologic homeostasis can and should be attended to, with strong animal and clinical evidence that their correction will have dramatic influence on the outcome of the newborn infant. This review addresses aspects of newborn care to which we can direct our attention currently, and which should result in a safe and efficacious improvement in the prognosis of the newborn with neonatal encephalopathy.
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Affiliation(s)
- Jerome Y Yager
- Department of Pediatrics, Stollery Children's Hospital, University of Alberta, Edmonton, Alberta, Canada.
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Thome UH, Ambalavanan N. Permissive hypercapnia to decrease lung injury in ventilated preterm neonates. Semin Fetal Neonatal Med 2009; 14:21-7. [PMID: 18974027 DOI: 10.1016/j.siny.2008.08.005] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Lung injury in ventilated premature infants occurs primarily through the mechanism of volutrauma, often due to the combination of high tidal volumes in association with a high end-inspiratory volume and occasionally end-expiratory alveolar collapse. Tolerating a higher level of arterial partial pressure of carbon dioxide (PaCO2) is considered as 'permissive hypercapnia' and when combined with the use of low tidal volumes may reduce volutrauma and lead to improved pulmonary outcomes. Permissive hypercapnia may also protect against hypocapnia-induced brain hypoperfusion and subsequent periventricular leukomalacia. However, extreme hypercapnia may be associated with an increased risk of intracranial hemorrhage. It may therefore be important to avoid large fluctuations in PaCO2 values. Recent randomized clinical trials in preterm infants have demonstrated that mild permissive hypercapnia is safe, but clinical benefits are modest. The optimal PaCO2 goal in clinical practice has not been determined, and the available evidence does not currently support a general recommendation for permissive hypercapnia in preterm infants.
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Affiliation(s)
- Ulrich H Thome
- Division of Neonatology, University Hospital for Children and Adolescents, 04103 Leipzig, Germany.
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Abstract
Mechanical ventilation using high tidal volume (VT) and transpulmonary pressure can damage the lung, causing ventilator-induced lung injury. Permissive hypercapnia, a ventilatory strategy for acute respiratory failure in which the lungs are ventilated with a low inspiratory volume and pressure, has been accepted progressively in critical care for adult, pediatric, and neonatal patients requiring mechanical ventilation and is one of the central components of current protective ventilatory strategies.
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Affiliation(s)
- Alex Rogovik
- Pediatric Research in Emergency Therapeutics (PRETx) Program, Division of Pediatric Emergency Medicine, Ambulatory Care Building, BC Children's Hospital, 4480 Oak Street, Vancouver, BC, Canada
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Abstract
UNLABELLED 'Permissive hypercapnia' is a familiar term in neonatal intensive care, given the widespread adoption of low-tidal-volume ventilation strategies applied with the goal of decreasing respiratory morbidity. Recent evidence suggesting that hypercapnic acidosis may itself have protective effects on the lung and other organs has led to the coining of a new phrase, 'therapeutic hypercapnia', which also encompasses the use of supplemental inspired CO(2). CONCLUSION Experimental evidence suggests that mild-moderate hypercapnia can improve tissue oxygenation and perfusion, which may ameliorate injury to the immature lung and brain. However, hypercapnia may also be associated with adverse outcomes, and the range of PaCO(2) levels that are both safe and effective for specific subsets of neonates has yet to be determined.
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Affiliation(s)
- Robert P Jankov
- Department of Paediatric, University of Toronto, Toronto, Ontario Canada.
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The potential role of carbon dioxide in the neuroimmunoendocrine changes following cerebral ischemia. Life Sci 2008; 83:381-7. [DOI: 10.1016/j.lfs.2008.07.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2008] [Revised: 06/29/2008] [Accepted: 07/17/2008] [Indexed: 12/18/2022]
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Hossmann KA, Traystman RJ. Cerebral blood flow and the ischemic penumbra. HANDBOOK OF CLINICAL NEUROLOGY 2008; 92:67-92. [PMID: 18790270 DOI: 10.1016/s0072-9752(08)01904-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Clarkson AN. Anesthetic-mediated protection/preconditioning during cerebral ischemia. Life Sci 2007; 80:1157-75. [PMID: 17258776 DOI: 10.1016/j.lfs.2006.12.022] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2006] [Revised: 12/04/2006] [Accepted: 12/13/2006] [Indexed: 01/22/2023]
Abstract
Cerebral ischemia is a multi-faceted neurodegenerative pathology that causes cellular injury to neurons within the central nervous system. In light of the underlying mechanisms being elucidated, clinical trials to find possible neuroprotectants to date have failed, thus highlighting the need for new putative targets to offer protection. Recent evidence has clearly shown that anesthetics can confer significant protection and or induce a preconditioning effect against cerebral ischemia-induced injury. This review will focus on the putative protection/preconditioning that is afforded by anesthetics, their possible interaction with GABA(A) and glutamate receptors and two-pore potassium channels. In addition, the interaction with inflammatory, apoptotic and underlying molecular (particularly immediately early genes and inducible nitric oxide synthase etc) pathways, the activation of K(ATP) channels and the ability to provide lasting protection will also be addressed.
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Affiliation(s)
- Andrew N Clarkson
- Department of Anatomy and Structural Biology, University of Otago, PO Box 913, Dunedin 9054, New Zealand.
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Abstract
Although neonatal brain injury occurs most frequently after a perinatal hypoxic-ischemic insult, recently studies have noted that variable causes such as metabolic and reperfusion events can result in, or aggravate, a brain insult. Current data suggest that about 2 to 5 of 1,000 live births in the United States and more so in developing countries experience a brain injury Approximately 20% to 40% of infants who survive the brain injury develop significant neurological and developmental impairments. The resulting impact on the child, family, and society presents a formidable challenge to health care professionals. Although several important insights have been gained in the last several years about the epidemiology, diagnosis, and mechanism of brain injury, management remains mostly a cocktail of controversial trials. This article provides a comprehensive review of the pathology, clinical manifestations, and timely management of infants with brain injury.
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Affiliation(s)
- Lina Kurdahi Badr Zahr
- School of Nursing, Azusa Pacific University, and David Geffen School of Medicine, University of California at Los Angeles, CA, USA.
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Kendall GS, Robertson NJ, Iwata O, Peebles D, Raivich G. N-methyl-isobutyl-amiloride ameliorates brain injury when commenced before hypoxia ischemia in neonatal mice. Pediatr Res 2006; 59:227-31. [PMID: 16439583 DOI: 10.1203/01.pdr.0000196805.68082.22] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Underphysiologic conditions, brain intracellular pH (pH(i)) is maintained at 7.03. Rebound brain intracellular alkalosis has been observed in experimental models and adult stroke after hypoxia/ischemia (HI). In term infants with neonatal encephalopathy (NE), an association exists between the magnitude of brain alkalosis and neurodevelopmental outcome, and there is increasing evidence to suggest that alkalosis may be deleterious to cell survival. Activation of the Na(+)/H(+) exchanger (NHE) is thought to be responsible for the rapid normalization of pH(i) and rebound alkalosis after reperfusion. We hypothesized that N-methyl-isobutyl-amiloride (MIA), an inhibitor of the NHE, would reduce brain injury in a model of neonatal HI. Seven-day-old mice underwent left carotid artery occlusion followed by exposure to 8% oxygen for 30 min (moderate insult) or 1 h (severe insult). Animals received MIA or saline 8 hourly starting 30 min before HI. Outcome was determined at 48 h by measuring viable tissue in the injured hemisphere (severe insult) or injury score and TUNEL staining (moderate insult). After the severe insult, MIA had a significant neuroprotective effect increasing forebrain tissue survival from 44% to 67%. After the moderate insult, damage was localized to the hippocampus where treatment resulted in a significant reduction in injury score and in TUNEL-positive cells. MIA was also shown to have a significant overall neuroprotective effect based on injury score after the moderate insult. Amiloride analogues are neuroprotective when commenced before HI in a mouse model.
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Affiliation(s)
- Giles S Kendall
- Centre for Perinatal Brain Protection and Repair, Department of Obstetrics and Gynaecology, University College London, UK
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Loepke AW, Golden JA, McCann JC, Kurth CD. Injury Pattern of the Neonatal Brain After Hypothermic Low-Flow Cardiopulmonary Bypass in a Piglet Model. Anesth Analg 2005; 101:340-348. [PMID: 16037141 DOI: 10.1213/01.ane.0000154199.67104.6a] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
UNLABELLED Low-flow cardiopulmonary bypass (LF-CPB) is a widely used modality in neonatal heart surgery. While facilitating surgical repair, it poses a risk of neurological injury caused by hypoperfusion. In the present study, we characterize the injury pattern and influencing factors in a piglet hypothermic LF-CPB model. Piglets were anesthetized, tracheally intubated, ventilated, and prepared for CPB. After LF-CPB for 150 min at 22 degrees C (brain) using pH-stat strategy, animals were allowed to survive for 2 or 9 days. Neurological status was assessed daily and magnetic resonance imaging scans were performed. Brains were assessed histologically. Functional neurological impairment was seen in 64%, 30%, and 0% of animals 1, 2, and 9 days after CPB, respectively. All animals showed histological brain damage, predominantly in neocortex and hippocampus, less so in basal ganglia, thalamus, white matter, and cerebellum. Cell death appeared as selective neuronal necrosis in the deeper layers in neocortex and CA1-4 sections in hippocampus. Even in a pH-stat strategy, less neocortical and hippocampal damage correlated with higher arterial partial pressure for carbon dioxide. Less hippocampal damage was associated with higher blood glucose levels. Less functional neurological impairment and basal ganglia damage correlated with higher postoperative hematocrit. IMPLICATIONS Neuronal injury after hypothermic low-flow cardiopulmonary bypass in a piglet model using pH-stat strategy occurs predominantly in deep neocortex and hippocampus. Factors mitigating injury were higher arterial carbon dioxide, hematocrit, and blood glucose levels.
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Affiliation(s)
- Andreas W Loepke
- *Department of Anesthesia, Cincinnati Children's Hospital Medical Center and University of Cincinnati College of Medicine, and Institute of Pediatric Anesthesia, Cincinnati Children's Hospital Research Foundation, Cincinnati, Ohio; and †Department of Pathology, Children's Hospital of Philadelphia and University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
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Robertson NJ, Bhakoo K, Puri BK, Edwards AD, Cox IJ. Hypothermia and amiloride preserve energetics in a neonatal brain slice model. Pediatr Res 2005; 58:288-96. [PMID: 16006423 DOI: 10.1203/01.pdr.0000170899.90479.1e] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A period of secondary energy failure consisting of a decline in phosphocreatine/inorganic phosphate (PCr/Pi), a rise in brain lactate, and alkaline intracellular pH (pH(i)) has been described in infants with neonatal encephalopathy. Strategies that ameliorate this energy failure may be neuroprotective. We hypothesized that a neonatal rat brain slice model undergoes a progressive decline in energetics, which can be ameliorated with hypothermia or amiloride. Interleaved phosphorus ((31)P) and proton ((1)H) magnetic resonance (MR) spectra were obtained from 350 microm neonatal rat brain slices over 8 h in a bicarbonate buffer at 37 degrees C and at 32 degrees C in 7- and 14-d models. (31)P MR spectra were obtained with amiloride in a bicarbonate-free buffer at 37 degrees C in the 14-d model. Findings were similar in 7- and 14-d models. In the 14-d model, there was a Pi doublet structure corresponding to alkaline pH(i) values of 7.50 +/- 0.02 and 7.21 +/- 0.04. Compared with the stabilized baseline of 100, at 5 h PCr/Pi was 65 +/- 6.3 and lactate/NAA was 187 +/- 3 at 37 degrees C, but PCr/Pi and lactate/NAA were not significantly different from baseline at 32 degrees C. Nucleotide triphosphate (NTP)/phosphomonoester (PME) was 0.93 +/- 0.23 at 37 degrees C and 1.81 +/- 0.21 at 32 degrees C at 5 h. With amiloride exposure in the 14-d model, baseline pH(i) values were 7.25 +/- 0.09 and 6.98 +/- 0.02 and NTP/PME was 1.81 +/- 0.05; these parameters were not significantly different at 5 h. Our interpretation of these findings is that the brain slice model underwent secondary energy failure, which was delayed with hypothermia or amiloride.
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Affiliation(s)
- Nicola J Robertson
- Department of Paediatrics, Division of Paediatrics, Obstetrics and Gynaecology, Division of Clinical Sciences, Hammersmith Hospital, Imperial College London, London W12 ONN, UK.
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Vannucci RC, Vannucci SJ. Perinatal Hypoxic-Ischemic Brain Damage: Evolution of an Animal Model. Dev Neurosci 2005; 27:81-6. [PMID: 16046840 DOI: 10.1159/000085978] [Citation(s) in RCA: 310] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2004] [Accepted: 08/19/2004] [Indexed: 01/09/2023] Open
Abstract
Early research in the Vannucci laboratory prior to 1981 focused largely on brain energy metabolism in the developing rat. At that time, there was no experimental model to study the effects of perinatal hypoxia-ischemia in the rodent, despite the tremendous need to investigate the pathophysiology of perinatal asphyxial brain damage in infants. Accordingly, we developed such a model in the postnatal day 7 rat, using a modification of the Levine preparation in the adult rat. Rat pups underwent unilateral common carotid artery ligation followed by exposure to systemic hypoxia (8% oxygen) at a constant temperature of 37 degrees C. Brain damage, seen histologically, was generally confined to the cerebral hemisphere ipsilateral to the arterial occlusion, and consisted of selective neuronal death or infarction, depending on the duration of the systemic hypoxia. Tissue injury was observed in the cerebral cortex, hippocampus, striatum, and thalamus. Subcortical and periventricular white matter injury was also observed. This model was originally described in the Annals of Neurology in 1981, and during the more than 20 years since that publication numerous investigations utilizing the model have been conducted in our laboratories as well as laboratories around the world. Cerebral blood flow and metabolic correlates have been fully characterized. Physiologic and pharmacologic manipulations have been applied to the model in search of neuroprotective strategies. More recently, molecular biologic alterations during and following the hypoxic-ischemic stress have been ascertained and the model has been adapted to the immature mouse for specific use in genetically altered animals. As predicted in the original article, the model has proven useful for the study of the short- and long-term effects of hypoxic-ischemic brain damage on motor activity, behavior, seizure incidence, and the process of maturation in the brain and other organ systems.
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Affiliation(s)
- Robert C Vannucci
- Department of Pediatrics (Pediatric Neurology), The Pennsylvania State University College of Medicine, Hershey, PA, USA
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Zhao P, Zuo Z. Prenatal hypoxia-induced adaptation and neuroprotection that is inducible nitric oxide synthase-dependent. Neurobiol Dis 2005; 20:871-80. [PMID: 15994093 DOI: 10.1016/j.nbd.2005.05.024] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2004] [Revised: 03/20/2005] [Accepted: 05/20/2005] [Indexed: 10/25/2022] Open
Abstract
The incidence of perinatal stroke is approximately 0.025%. About two thirds of these patients develop long-lasting neurological deficits. Preconditioning-induced neuroprotection, a phenomenon in which application of a stimulus induces brain ischemic tolerance, is investigated to improve outcome after a perinatal stroke. We applied prenatal hypoxia to fetuses by exposing 22-day pregnant mother rats to 15% oxygen for 30 min and subjected newborns with or without this prenatal hypoxia to brain ischemia 48 h later. Newborns with the prenatal hypoxia had a lower mortality rate, less brain tissue and neuronal loss and fewer active caspase 3 (an indicator for cell apoptosis) positive brain cells than newborns with the brain ischemia only. This neuroprotection was abolished by an inhibitor of inducible nitric oxide synthase (iNOS). The expression of iNOS proteins but not endothelial and neuronal NOS proteins was increased by the prenatal hypoxia. Thus, the prenatal hypoxia-induced neuroprotection may be iNOS-dependent.
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Affiliation(s)
- Ping Zhao
- Department of Anesthesiology, Neuroscience and Neurological Surgery, University of Virginia, One Hospital Drive, PO Box 800710, Charlottesville, VA 22908-0710, USA
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Clarkson AN, Liu H, Rahman R, Jackson DM, Appleton I, Kerr DS. Clomethiazole: mechanisms underlying lasting neuroprotection following hypoxia-ischemia. FASEB J 2005; 19:1036-8. [PMID: 15809357 DOI: 10.1096/fj.04-3367fje] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Damage after hypoxia-ischemia (HI) is observed in both cortical and subcortical regions. In this study, we employed a "Levine" rat model of HI (left carotid ligation + 1 h global hypoxia on PND-26) and used histological and electrophysiological paradigms to assess the long-term neuroprotective properties of clomethiazole (CMZ; a GABA(A) receptor modulator). Key enzymes involved in inflammation, namely nitric oxide synthase (NOS) and arginase, were also examined to assess potential CMZ mechanisms not involving GABA-R activation. Assessments were carried out 3 and 90 days post-HI. Extensive CNS lesions were evident after HI ipsilaterally at both short- and long-term intervals. CMZ significantly decreased the lesion size at 3 and 90 days (P<0.01; P<0.05). Evoked field potential analyses were used to assess hippocampal CA1 neuronal activity ex vivo. Electrophysiological measurements contralateral to the occlusion revealed impaired neuronal function after HI relative to short- and long-term controls (P<0.001, 3 and 14 days; P<0.01, 90 days), with CMZ treatment providing near complete protection (P<0.001 at 3 and 14 days; P<0.01 at 90 days). Both NOS and arginase activities were significantly increased at 3 days (P<0.01), with arginase remaining elevated at 90 days post-HI (P<0.05) ipsilaterally. CMZ suppressed the HI-induced increase in iNOS and arginase activities (P<0.001; P<0.05). These data provide evidence of long-term functional neuroprotection by CMZ in a model of HI. We further conclude that under conditions of HI, functional deficits are not restricted to the ipsilateral hemisphere and are due, at least in part, to changes in the activity of NOS and arginase.
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Affiliation(s)
- Andrew N Clarkson
- Department of Pharmacology and Toxicology, University of Otago School of Medical Sciences, Dunedin, New Zealand
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Abstract
Newborn piglets were submitted to normobaric hypoxia (5% O2, 95% N2) for either 1 or 4 h. The effects of hypoxia on the neonatal brain were characterized through a time-course analysis of levels of various proteins such as heat shock proteins (HSP27, 70, and 90), hypoxia inducible factor-1alpha (HIF-1alpha), neuronal nitric oxide synthase (nNOS), hemeoxygenase-2 (HO-2), and caspase-3. The expression of these proteins was determined at different stages of recovery up to 72 h in cerebellum, cortex, and hippocampus by Western blot analysis in hypoxic maintained animals that were made hypoxic at either 20 or 37 degrees C. In all regions of the brain, HIF-1alpha and HSP27 expression were strongly increased until 22 h of recovery. No significant changes were observed for HSP70, HSP90, and HO-2. A small elevation of expression of nNOS was observed at early stages in the cerebellum and the cortex with no change in the hippocampus. Expression of caspase 3 was strongly increased in the cortex 24 and 48 h after hypoxia but unchanged in the hippocampus. These results are presented in terms of the porcine model of nonischemic hypoxia and its delayed neuronal effects on the cerebral outcome. Because of their recently established biochemical and functional interactions, the expression of the main HSPs, HIF-1alpha, nNOS, and caspase-3 after hypoxia are delineated.
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Affiliation(s)
- Magali Chiral
- Sciences et Productions Animales, Agrocampus, 65, rue de Saint-Brieuc, CS 84215, 35042 Rennes Cedex, France
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Ma D, Hossain M, Rajakumaraswamy N, Arshad M, Sanders RD, Franks NP, Maze M. Dexmedetomidine produces its neuroprotective effect via the α2A-adrenoceptor subtype. Eur J Pharmacol 2004; 502:87-97. [PMID: 15464093 DOI: 10.1016/j.ejphar.2004.08.044] [Citation(s) in RCA: 196] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2004] [Revised: 08/09/2004] [Accepted: 08/19/2004] [Indexed: 10/26/2022]
Abstract
Which of the three alpha2-adrenoceptor subtypes of alpha2A, alpha2B, or alpha2C mediates the neuroprotective effect of dexmedetomidine was examined in cell culture as well as in an in vivo model of neonatal asphyxia. Dexmedetomidine dose-dependently attenuated neuronal injury (IC50=83+/-1 nM) in neuronal-glial co-cultures derived from wild-type mice; contrastingly, dexmedetomidine did not exert neuroprotection in injured cells from transgenic mice (D79N) expressing dysfunctional alpha2A-adrenoceptors. An alpha2A-adrenoceptor subtype-preferring antagonist 2-[(4,5-Dihydro-1H-imidazol-2-yl)methyl]-2,3-dihydro-1-methyl-1H-isoindole maleate (BRL44408) completely reversed dexmedetomidine-induced neuroprotection, while other subtype-preferring antagonists 2-[2-(4-(2-Methoxyphenyl)piperazin-1-yl)ethyl]-4,4-dimethyl-1,3-(2H,4H)-isoquinolindione dihydrochloride (ARC239) (alpha2B) and rauwolscine (alpha2C) had no significant effect on the neuroprotective effect of dexmedetomidine in neuronal-glial co-cultures. Dexmedetomidine also protected against exogenous glutamate induced cell death in pure cortical neuron cultures assessed by flow cytometry and reduced both apoptotic and necrotic types of cell death. Likewise this neuroprotective effect was antagonised by BRL44408 but not ARC239 or rauwolscine. Dexmedetomidine exhibited dose-dependent protection against brain matter loss in vivo (IC50=40.3+/-6.1 microg/kg) and improved the neurologic functional deficit induced by the hypoxic-ischemic insult. Protection by dexmedetomidine against hypoxic-ischemic-induced brain matter loss was reversed by the alpha2A-adrenoceptor subtype-preferring antagonist BRL44408; neither ARC239 nor rauwolscine reversed the neuroprotective effect of dexmedetomidine in vivo. Our data suggest that the neuroprotective effect of dexmedetomidine is mediated by activation of the alpha2A adrenergic receptor subtype.
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Affiliation(s)
- Daqing Ma
- Department of Anaesthetics, Imperial College London, Chelsea & Westminster Hospital, 369 Fulham Road, London SW10 9NH, UK
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O' Croinin D, Ni Chonghaile M, Higgins B, Laffey JG. Bench-to-bedside review: Permissive hypercapnia. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2004; 9:51-9. [PMID: 15693984 PMCID: PMC1065087 DOI: 10.1186/cc2918] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Current protective lung ventilation strategies commonly involve hypercapnia. This approach has resulted in an increase in the clinical acceptability of elevated carbon dioxide tension, with hypoventilation and hypercapnia 'permitted' in order to avoid the deleterious effects of high lung stretch. Advances in our understanding of the biology of hypercapnia have prompted consideration of the potential for hypercapnia to play an active role in the pathogenesis of inflammation and tissue injury. In fact, hypercapnia may protect against lung and systemic organ injury independently of ventilator strategy. However, there are no clinical data evaluating the direct effects of hypercapnia per se in acute lung injury. This article reviews the current clinical status of permissive hypercapnia, discusses insights gained to date from basic scientific studies of hypercapnia and acidosis, identifies key unresolved concerns regarding hypercapnia, and considers the potential clinical implications for the management of patients with acute lung injury.
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Affiliation(s)
- Donall O' Croinin
- Clinical Research Fellow, Department of Physiology, University College Dublin, Dublin
| | - Martina Ni Chonghaile
- Clinical Research Fellow, Department of Anaesthesia, University College Hospital, and Department of Anaesthesia, Clinical Sciences Institute, National University of Ireland, Galway, Ireland
| | - Brendan Higgins
- Postdoctoral Research Fellow, Department of Anaesthesia, Clinical Sciences Institute, National University of Ireland, Galway, Ireland
| | - John G Laffey
- Clinical Lecturer, Department of Anaesthesia, University College Hospital, and Department of Anaesthesia, Clinical Sciences Institute, National University of Ireland, Galway, Ireland
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Ley D, Oskarsson G, Bellander M, Hernandez-Andrade E, Lingman G, Marsal K, Olsson T, Pesonen E, Thorngren-Jerneck K, Werner O, Hellström-Westas L. Different responses of myocardial and cerebral blood flow to cord occlusion in exteriorized fetal sheep. Pediatr Res 2004; 55:568-75. [PMID: 14739362 DOI: 10.1203/01.pdr.0000113785.66455.e7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Type and duration of fetal asphyxial insult affect the distribution of blood flow to the heart and brain. The purpose of this study was to describe dynamic and quantitative changes in regional myocardial and cerebral blood flow (CBF) during fetal asphyxia induced by total occlusion of the umbilical cord. Eleven exteriorized fetal sheep were subjected to total umbilical cord occlusion and five fetal sheep served as sham controls. Regional blood flow (BF) to the brain and heart was quantified using radioactive microspheres before and after 5 min of occlusion and finally when fetal mean arterial blood pressure had decreased below 25 mm Hg, 9.8 (0.8) [mean (SD)] min after occlusion. Right coronary arterial (RCA) blood flow velocity and carotid BF were registered continuously. Mean values of arterial pH and oxygen content (mL O(2)/100 mL) were 7.08 (0.11) and 4.4 (2.9) before cord occlusion and decreased to 6.83 (0.05) and 1.4 (0.9) at 5 min after occlusion (p < 0.01, respectively). Carotid BF was significantly below preocclusion values by 2.5 min (p < 0.05), whereas RCA velocity time integral per minute remained above preocclusion values for 9 min. CBF decreased from 316 (24) before cord occlusion to 156 (30) mL/min/100 g at 5 min (p < 0.01), whereas right myocardial BF was maintained at 792 (125) and 751 (183) mL/min/100 g, respectively. CBF decreased rapidly after total cord occlusion whereas myocardial BF increased and was maintained until shortly before cardiac arrest, suggesting the myocardium to be better preserved during this type of insult in already partially asphyxiated fetuses.
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Affiliation(s)
- David Ley
- Department of Pediatrics, Lunds University Hospital, 221 85 Lund, Sweden.
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46
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Laffey JG, O'Croinin D, McLoughlin P, Kavanagh BP. Permissive hypercapnia--role in protective lung ventilatory strategies. Intensive Care Med 2004; 30:347-56. [PMID: 14722644 DOI: 10.1007/s00134-003-2051-1] [Citation(s) in RCA: 142] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2003] [Accepted: 09/29/2003] [Indexed: 11/29/2022]
Abstract
"Permissive hypercapnia" is an inherent element of accepted protective lung ventilation. However, there are no clinical data evaluating the efficacy of hypercapnia per se, independent of ventilator strategy. In the absence of such data, it is necessary to determine whether the potential exists for an active role for hypercapnia, distinct from the demonstrated benefits of reduced lung stretch. In this review, we consider four key issues. First, we consider the evidence that protective lung ventilatory strategies improve survival and we explore current paradigms regarding the mechanisms underlying these effects. Second, we examine whether hypercapnic acidosis may have effects that are additive to the effects of protective ventilation. Third, we consider whether direct elevation of CO(2), in the absence of protective ventilation, is beneficial or deleterious. Fourth, we address the current evidence regarding the buffering of hypercapnic acidosis in ARDS. These perspectives reveal that the potential exists for hypercapnia to exert beneficial effects in the clinical context. Direct administration of CO(2) is protective in multiple models of acute lung and systemic injury. Nevertheless, several specific concerns remain regarding the safety of hypercapnia. At present, protective ventilatory strategies that involve hypercapnia are clinically acceptable, provided the clinician is primarily targeting reduced tidal stretch. There are insufficient clinical data to suggest that hypercapnia per se should be independently induced, nor do outcome data exist to support the practice of buffering hypercapnic acidosis. Rapidly advancing basic scientific investigations should better delineate the advantages, disadvantages, and optimal use of hypercapnia in ARDS.
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Affiliation(s)
- John G Laffey
- Department of Anaesthesia, University College Hospital, Galway and Clinical Sciences Institute, National University of Ireland, Galway, Ireland,
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Peterson BS. Brain Imaging Studies of the Anatomical and Functional Consequences of Preterm Birth for Human Brain Development. Ann N Y Acad Sci 2003; 1008:219-37. [PMID: 14998887 DOI: 10.1196/annals.1301.023] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Premature birth can have devastating effects on brain development and long-term functional outcome. Rates of psychiatric illness and learning difficulties are high, and intelligence on average is lower than population means. Brain imaging studies of infants born prematurely have demonstrated reduced volumes of parietal and sensorimotor cortical gray matter regions. Studies of school-aged children have demonstrated reduced volumes of these same regions, as well as in temporal and premotor regions, in both gray and white matter. The degrees of these anatomical abnormalities have been shown to correlate with cognitive outcome and with the degree of fetal immaturity at birth. Functional imaging studies have shown that these anatomical abnormalities are associated with severe disturbances in the organization and use of neural systems subserving language, particularly for school-aged children who have low verbal IQs. Animal models suggest that hypoxia-ischemia may be responsible at least in part for some of the anatomical and functional abnormalities. Increasing evidence suggests that a host of mediators for hypoxic-ischemic insults likely contribute to the disturbances in brain development in preterm infants, including increased apoptosis, free-radical formation, glutamatergic excitotoxicity, and alterations in the expression of a large number of genes that regulate brain maturation, particularly those involved in the development of postsynaptic neurons and the stabilization of synapses. The collaboration of both basic neuroscientists and clinical researchers is needed to understand how normal brain development is derailed by preterm birth and to develop effective prevention and early interventions for these often devastating conditions.
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Affiliation(s)
- Bradley S Peterson
- Columbia College of Physicians & Surgeons and the New York State Psychiatric Institute, Unit 74, 1051 Riverside Drive, New York, NY 10032, USA.
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Robertson NJ, Cowan FM, Cox IJ, Edwards AD. Brain alkaline intracellular pH after neonatal encephalopathy. Ann Neurol 2002; 52:732-42. [PMID: 12447926 DOI: 10.1002/ana.10365] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Experimental studies demonstrate an alkaline shift in brain intracellular pH (pH(i)) after hypoxia-ischemia (HI). In infants with neonatal encephalopathy after HI, our aims were to assess (1) brain pH(i) during the first 2 weeks after birth in infants categorized according to magnetic resonance imaging (MRI) during the first 2 weeks after birth and at more than 3 months of age, and neurodevelopmental outcome at 1 year; (2) the relationship between brain pH(i) and lactate/creatine; and (3) duration of alkaline brain pH(i). Seventy-eight term infants with neonatal encephalopathy were studied using MR techniques. One hundred and fifty-one studies were performed throughout the first year including 56 studies of 50 infants during the first 2 weeks after birth. pH(i) was calculated using phosphorus-31 MR spectroscopy and lactate/creatine was measured using proton MRS. The mean (standard deviation [SD]) brain pH(i) during the first 2 weeks after birth in infants with severely abnormal versus normal MRI was 7.24 (SD, 0.17) versus 7.04 (SD, 0.05; p < 0.001); in infants who subsequently developed cerebral atrophy versus those who did not: 7.23 (SD, 0.17) versus 7.06 (SD, 0.06; p < 0.05); in infants who died or had a severe neurodevelopmental impairment versus normal outcome: 7.28 (SD, 0.15) versus 7.11 (SD, 0.09; p < 0.05). Brain alkalosis was associated with increased brain lactate/creatine (p < 0.001). pH(i) remained more alkaline in the severe outcome group up to 20 weeks after birth (p < 0.05).
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Affiliation(s)
- Nicola J Robertson
- Department of Paediatrics, Division of Paediatrics, Obstetrics and Gynaecology, Imperial College School of Science, Technology and Medicine, Hammersmith Hospital Campus, DuCane Road, LondonW12 0NN, UK.
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Abstract
Although lifesaving, mechanical ventilation can result in lung injury and contribute to the development of bronchopulmonary dysplasia. The most critical determinants of lung injury are tidal volume and end-inspiratory lung volume. Permissive hypercapnia offers to maintain gas exchange with lower tidal volumes and thus decrease lung injury. Further physiologic benefits include improved oxygen delivery and neuroprotection, the latter through both avoidance of accidental hypocapnia, which is associated with a poor neurologic outcome, and direct cellular effects. Clinical trials in adults with acute respiratory failure indicated improved survival and reduced incidence of organ failure in subjects managed with low tidal volumes and permissive hypercapnia. Retrospective studies in low birth weight infants found an association of bronchopulmonary dysplasia with low PaCO(2). Randomized clinical trials of low birth weight infants did not achieve sufficient statistical power to demonstrate a reduction of BPD by permissive hypercapnia, but strong trends indicated the possibility of important benefits without increased adverse events. Herein, we review the mechanisms leading to lung injury, the physiologic effects of hypercapnia, the dangers of hypocapnia, and the available clinical data.
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Affiliation(s)
- Ulrich H Thome
- Division of Neonatology and Pediatric Critical Care, Children's Hospital, University of Ulm, 89070 Ulm, Germany
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Gressens P, Rogido M, Paindaveine B, Sola A. The impact of neonatal intensive care practices on the developing brain. J Pediatr 2002; 140:646-53. [PMID: 12072865 DOI: 10.1067/mpd.2002.123214] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Pierre Gressens
- Service de Neurologie Pédiatrique and INSERM E 9935, Hôpital Robert-Debré, Paris, France
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