101
|
Horan M, Azzopardi D, Edwards AD, Firmin RK, Field D. Lack of influence of mild hypothermia on amplitude integrated-electroencephalography in neonates receiving extracorporeal membrane oxygenation. Early Hum Dev 2007; 83:69-75. [PMID: 16814962 DOI: 10.1016/j.earlhumdev.2006.05.004] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2006] [Revised: 04/28/2006] [Accepted: 05/04/2006] [Indexed: 12/01/2022]
Abstract
OBJECTIVE To observe amplitude integrated electroencephalography (aEEG) in neonates receiving ECMO and to determine whether mild hypothermia influenced the aEEG recording. METHODS Twenty-six consecutive neonates enrolled in a pilot study of mild hypothermia during ECMO were studied. The first group (N=6) was maintained at 37 degrees C throughout the study period. Subsequent groups were cooled to 36 degrees C (N=4), 35 degrees C (N=5), and finally 34 degrees C (N=6) respectively for 24 h and the final group (N=5) to 34 degrees C for 48 h before being rewarmed to 37 degrees C. The aEEG was recorded continuously during the first 5 days of ECMO. The aEEG was classified as normal, moderately or severely suppressed and examined for the occurrence of seizures. To assess the effect of temperature, the aEEG was compared over 12 h during the final 6 h of cooling and during the first 6 h once infants were rewarmed. RESULTS No change in aEEG amplitude was noted over the temperature range studied. Of the 26 traces obtained, 16 (62%) were normal throughout, 6 (23%) were intermittently moderately abnormal and 1 (14%) was severely abnormal. Three (11%) traces had periods of frequent seizure activity and these were not associated with clinical manifestations in two neonates. In one infant who suffered a cerebral haemorrhage, the aEEG became abnormal before cranial ultrasound abnormalities were apparent. CONCLUSIONS Continuous cerebral monitoring with aEEG is feasible during ECMO and may add information to clinical examination. Mild hypothermia to 34 degrees C for up to 48 h does not influence the aEEG suggesting that cerebral monitoring with aEEG is possible during mild hypothermia.
Collapse
Affiliation(s)
- Marie Horan
- The Department of Child Health, University of Leicester, Leicester, UK.
| | | | | | | | | |
Collapse
|
102
|
|
103
|
Abstract
BACKGROUND Accumulating evidence points to an evolving process of brain injury after intrapartum hypoxia-ischemia that initiates in utero and extends into a recovery period. It is during this recovery period that the potential for neuroprotection exists. OBJECTIVE This discussion briefly reviews the cellular characteristics of hypoxic-ischemic cerebral injury and the current and future therapeutic strategies aimed at ameliorating ongoing brain injury after intrapartum hypoxia-ischemia. METHODS As part of the Newborn Drug Development Initiative, the National Institute of Child Health and Human Development and the US Food and Drug Administration cosponsored a workshop held March 29 and 30, 2004, in Baltimore, Maryland. Information for this article was gathered during that workshop. Literature searches of MEDLINE (Ovid) and EMBASE (1996-2005) were also conducted; search terms included newborn, infant, hypoxia-ischemia, hypoxic-ischemic encephalopathy, asphyxia, pathogenesis, treatment, reperfusion injury, and mechanisms, as well as numerous interventions (ie, therapeutic hypothermia, magnesium, and barbiturates). RESULTS The acute brain injury results from the combined effects of cellular energy failure, acidosis, glutamate release, intracellular calcium accumulation, lipid peroxidation, and nitric oxide neurotoxicity that serve to disrupt essential components of the cell, resulting in death. Many factors, including the duration or severity of the insult, influence the progression of cellular injury after hypoxia-ischemia. A secondary cerebral energy failure occurs from 6 to 48 hours after the primary event and may involve mitochondrial dysfunction secondary to extended reactions from primary insults (eg, calcium influx, excitatory neurotoxicity, oxygen free radicals, or nitric oxide formation). Some evidence suggests that circulatory and endogenous inflammatory cells/mediators also contribute to ongoing brain injury. The goals of management of a newborn infant who has sustained a hypoxic-ischemic insult and is at risk for injury should include early identification of the infant at highest risk for evolving injury, supportive care to facilitate adequate perfusion and nutrients to the brain, attempts to maintain glucose homeostasis, and consideration of interventions to ameliorate the processes of ongoing brain injury. Recent evidence suggests a potential role for modest hypothermia (ie, a reduction in core body temperature to -34 degrees C) administered to high-risk term infants within 6 hours of birth. Either selective (head) or systemic (body) cooling reduces the incidence of death and/or moderate to severe disability at 18-month follow-up. Additional strategies-including the use of oxygen free radical inhibitors and scavengers, excitatory amino acid antagonists, and growth factors; prevention of nitric oxide formation; and blockage of apoptotic pathways-have been evaluated experimentally but have not been replicated in a systematic manner in the human neonate. Other avenues of potential neuroprotection that have been studied in immature animals include platelet-activating factor antagonists, adenosinergic agents, monosialoganglioside GM1, insulin-like growth factor-1, and erythropoietin. CONCLUSIONS Much progress has been made toward understanding the mechanisms contributing to ongoing brain injury after intrapartum hypoxia-ischemia. This should facilitate more specific pharmacologic intervention strategies that might provide neuroprotection during the reperfusion phase of injury.
Collapse
Affiliation(s)
- Jeffrey M Perlman
- Weill Medical College of Cornell University, New York, New York 10021, USA.
| |
Collapse
|
104
|
Bennet L, Roelfsema V, George S, Dean JM, Emerald BS, Gunn AJ. The effect of cerebral hypothermia on white and grey matter injury induced by severe hypoxia in preterm fetal sheep. J Physiol 2006; 578:491-506. [PMID: 17095565 PMCID: PMC2075155 DOI: 10.1113/jphysiol.2006.119602] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Prolonged, moderate cerebral hypothermia is consistently neuroprotective after experimental hypoxia-ischaemia; however, it has not been tested in the preterm brain. Preterm (0.7 gestation) fetal sheep received complete umbilical cord occlusion for 25 min followed by cerebral hypothermia (fetal extradural temperature reduced from 39.4 +/- 0.3 to 29.5 +/- 2.6 degrees C) from 90 min to 70 h after the end of occlusion or sham cooling. Occlusion led to severe acidosis and profound hypotension, which recovered rapidly after release of occlusion. After 3 days recovery the EEG spectral frequency, but not total intensity, was increased in the hypothermia-occlusion group compared with normothermia-occlusion. Hypothermia was associated with a significant overall reduction in loss of immature oligodendrocytes in the periventricular white matter (P < 0.001), and neuronal loss in the hippocampus and basal ganglia (P < 0.001), with suppression of activated caspase-3 and microglia (isolectin-B4 positive). Proliferation was significantly reduced in periventricular white matter after occlusion (P < 0.05), but not improved after hypothermia. In conclusion, delayed, prolonged head cooling after a profound hypoxic insult in the preterm fetus was associated with a significant reduction in loss of neurons and immature oligodendroglia, with evidence of EEG and haemodynamic improvement after 3 days recovery, but also with a persisting reduction in proliferation of cells in the periventricular region. Further studies are required to evaluate the long-term impact of cooling on brain growth and maturation.
Collapse
Affiliation(s)
- L Bennet
- Department of Physiology and Paediatrics, University of Auckland, Auckland, New Zealand
| | | | | | | | | | | |
Collapse
|
105
|
Shany E, Goldstein E, Khvatskin S, Friger MD, Heiman N, Goldstein M, Karplus M, Galil A. Predictive value of amplitude-integrated electroencephalography pattern and voltage in asphyxiated term infants. Pediatr Neurol 2006; 35:335-42. [PMID: 17074604 DOI: 10.1016/j.pediatrneurol.2006.06.007] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2006] [Revised: 04/19/2006] [Accepted: 06/19/2006] [Indexed: 11/23/2022]
Abstract
The aim of this study was to correlate amplitude-integrated electroencephalography soon after birth with neurodevelopmental outcome in children who suffered from hypoxic-ischemic encephalopathy. Near term infants with hypoxic-ischemic encephalopathy and amplitude-integrated electroencephalography recording before 6 hours of age were included. Neurologic and cognitive outcome were assessed at 30 months of age and over. Outcome was correlated with either the pattern or voltage of the tracing. Thirty-nine infants were included. Eight died in the immediate neonatal period. At the age of 3 and 6 hours, sensitivity of low voltage to poor outcome was 33% and 42% respectively and of burst suppression pattern to poor outcome was 83% and 75% respectively. Association of voltage to outcome was significant only at 6 hours of age (P = 0.025). Association of pattern to outcome was significant both at 3 and 6 hours of age (P = 0.003, 0.008). These data on amplitude-integrated electroencephalography predictive value early in life were similar to previous studies. Burst suppression pattern, as early as 3 hours of age, is associated with poor outcome. At the age of 6 hours, both low voltage and burst suppression are associated with poor outcome. Pattern seems more sensitive than voltage.
Collapse
Affiliation(s)
- Eilon Shany
- Department of Neonatology, Soroka University Medical Center, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
| | | | | | | | | | | | | | | |
Collapse
|
106
|
Northington FJ. Brief update on animal models of hypoxic-ischemic encephalopathy and neonatal stroke. ILAR J 2006; 47:32-8. [PMID: 16391429 DOI: 10.1093/ilar.47.1.32] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The discovery of safe and effective therapies for perinatal hypoxia ischemia (HI) and stroke remains an unmet goal of neonatal-perinatal medicine. Because of the many developmental and functional differences between the neonatal brain and the adult brain, the ability to extrapolate adult data to the neonatal condition is very limited. For this reason, it is incumbent on scientists in the field of neonatal brain injury to address the questions of therapeutic efficacy of an array of potential therapies in a developmentally appropriate model. Toward that end, a number of new models of neonatal HI and stroke have been introduced recently. Additionally, some of the established models have been adapted to different species and different ages, giving scientists a greater choice of models for the study of neonatal HI and stroke. Many of these models are now also being used for functional and behavioral testing, an absolute necessity for preclinical therapeutic trials. This review focuses primarily on the newly developed models, recent adaptations to established models, and the studies of functional outcome that have been published since 2000.
Collapse
Affiliation(s)
- Frances J Northington
- Department of Pediatrics, Eudowood Neonatal Pulmonary Division, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| |
Collapse
|
107
|
Shah DK, Lavery S, Doyle LW, Wong C, McDougall P, Inder TE. Use of 2-channel bedside electroencephalogram monitoring in term-born encephalopathic infants related to cerebral injury defined by magnetic resonance imaging. Pediatrics 2006; 118:47-55. [PMID: 16818548 DOI: 10.1542/peds.2005-1294] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
OBJECTIVE Single-channel amplitude-integrated electroencephalography has been shown to be predictive of neurodevelopmental outcome in term infants with hypoxic-ischemic encephalopathy. We describe the relationship of quantifiable electroencephalogram (EEG) measures, obtained using a 2-channel digital bedside EEG monitor from term newborn infants with encephalopathy and/or seizures, to cerebral injury defined qualitatively by MRI. METHODS Median values of minimum, mean, and maximum EEG amplitude were obtained from term-born encephalopathic infants during a 2-hour seizure-free period obtained within 72 hours of admission. Infants underwent MRI with images qualitatively scored for abnormalities of cortex, white matter, deep nuclear gray matter, and posterior limb of the internal capsule. Eighty-six infants had EEG measures related to qualitative MRI outcomes. RESULTS The most common diagnosis was hypoxic ischemic encephalopathy (n = 40). For all infants there was a negative relationship between EEG amplitude measures and MRI abnormality scores assessed on a scale from 4 to 15, with a higher score indicating more abnormalities. This relationship was strongest for the minimum amplitude measures in both hemispheres; that is, for every unit increase in score there was a mean drop of 0.41 microV for the left cerebral hemisphere, with 35% of variance explained. This relationship persisted on sub-group analyses for infants with hypoxic-ischemic encephalopathy, infants with other diagnoses and infants monitored after the first 24 hours of life. Using an MRI abnormality score cutoff of 8 or worse for cerebral injury in infants with hypoxic-ischemic encephalopathy, a minimum amplitude of 4 microV showed a higher specificity (80%: left hemisphere), whereas a minimum amplitude of 6 muV showed a higher sensitivity (92%: left hemisphere). CONCLUSIONS Bedside EEG measures in term-born encephalopathic infants are related to the severity of cerebral injury as defined by qualitative MRI. A minimum amplitude of <4 microV appears useful in predicting outcome.
Collapse
Affiliation(s)
- Divyen K Shah
- Department of Neonatology, Royal Children's and Royal Women's Hospitals, Melbourne, Australia
| | | | | | | | | | | |
Collapse
|
108
|
Abstract
The possibility that hypothermia during or after resuscitation from asphyxia at birth, or cardiac arrest in adults, might reduce evolving damage has tantalized clinicians for a very long time. It is now known that severe hypoxia-ischemia may not necessarily cause immediate cell death, but can precipitate a complex biochemical cascade leading to the delayed neuronal loss. Clinically and experimentally, the key phases of injury include a latent phase after reperfusion, with initial recovery of cerebral energy metabolism but EEG suppression, followed by a secondary phase characterized by accumulation of cytotoxins, seizures, cytotoxic edema, and failure of cerebral oxidative metabolism starting 6 to 15 h post insult. Although many of the secondary processes can be injurious, they appear to be primarily epiphenomena of the 'execution' phase of cell death. Studies designed around this conceptual framework have shown that moderate cerebral hypothermia initiated as early as possible before the onset of secondary deterioration, and continued for a sufficient duration in relation to the severity of the cerebral injury, has been associated with potent, long-lasting neuroprotection in both adult and perinatal species. Two large controlled trials, one of head cooling with mild hypothermia, and one of moderate whole body cooling have demonstrated that post resuscitation cooling is generally safe in intensive care, and reduces death or disability at 18 months of age after neonatal encephalopathy. These studies, however, show that only a subset of babies seemed to benefit. The challenge for the future is to find ways of improving the effectiveness of treatment.
Collapse
Affiliation(s)
- A J Gunn
- Dept of Physiology, The University of Auckland, New Zealand.
| | | |
Collapse
|
109
|
Azra Haider B, Bhutta ZA. Birth asphyxia in developing countries: current status and public health implications. Curr Probl Pediatr Adolesc Health Care 2006; 36:178-88. [PMID: 16631096 DOI: 10.1016/j.cppeds.2005.11.002] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Batool Azra Haider
- Department of Paediatrics and Child Health, The Aga Khan University, Karachi, Pakistan
| | | |
Collapse
|
110
|
Gebauer CM, Knuepfer M, Robel-Tillig E, Pulzer F, Vogtmann C. Hemodynamics among neonates with hypoxic-ischemic encephalopathy during whole-body hypothermia and passive rewarming. Pediatrics 2006; 117:843-50. [PMID: 16510666 DOI: 10.1542/peds.2004-1587] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVE To assess changes in cardiac performance, with Doppler echocardiography, among newborns with hypoxic-ischemic encephalopathy during mild therapeutic hypothermia and during rewarming. METHODS For 7 asphyxiated neonates (birth weight: 1840-3850 g; umbilical artery pH: 6.70-6.95) who received mild whole-body hypothermia, the following hemodynamic parameters were determined immediately before rewarming (33 degrees C) and during passive rewarming (35 degrees C and 37 degrees C): heart rate, systolic and diastolic blood pressure, core and peripheral temperatures, left ventricular ejection time, mean velocity of aortic flow, stroke volume, and cardiac output. RESULTS Heart rate decreased during hypothermia. Bradycardia, with heart rates below 80 beats per minute, did not occur. The median difference between core and peripheral temperatures decreased from 2.0 degrees C (range: 0-6.2 degrees C) during hypothermia to 0.7 degrees C (range: 0.4-1.9 degrees C) at normothermia. Cardiac output was reduced to 67% and stroke volume to 77% of the posthypothermic level. The median heart rate was 129 beats per minute before rewarming and increased to 148 beats per minute during complete rewarming. Before and during passive rewarming, hypotension was not observed. Before, during, and at the end of rewarming, the following parameters increased: mean velocity of aortic flow (median: 44, 55, and 58 cm/second, respectively), stroke volume (median: 1.42, 1.55, and 1.94 mL/kg, respectively), and cardiac output (median: 169, 216, and 254 mL/kg per minute, respectively). Left ventricular ejection time remained unchanged. CONCLUSIONS Whole-body hypothermia resulted in reduced cardiac output, which reached normal levels at the end of passive rewarming, at normothermia. Physiologic cardiovascular mechanisms seemed to be intact to provide sufficient tissue perfusion, with normal blood lactate levels.
Collapse
Affiliation(s)
- Corinna Mirjam Gebauer
- Department of Neonatology, Children's Hospital, University of Leipzig, Leipzig, Germany.
| | | | | | | | | |
Collapse
|
111
|
Abstract
Well constructed and carefully analysed trials of hypothermic neural rescue therapy for infants with neonatal encephalopathy have recently been reported. The data suggest that either selective head cooling or total body cooling reduces the combined chance of death or disability after birth asphyxia. However, as there are still unanswered questions about these treatments, many may still feel that further data are needed before health care policy can be changed to make cooling the standard of care for all babies with suspected birth asphyxia.
Collapse
Affiliation(s)
- A D Edwards
- Division of Clinical Sciences, Faculty of Medicine, Imperial College London, UK.
| | | |
Collapse
|
112
|
|
113
|
Speer M, Perlman JM. Modest hypothermia as a neuroprotective strategy in high-risk term infants. Clin Perinatol 2006; 33:169-82, ix. [PMID: 16533643 DOI: 10.1016/j.clp.2005.11.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This article briefly reviews the pathogenesis of hypoxic-ischemic cerebral injury, the experimental data, and clinical studies that have evaluated the potential therapeutic benefit of modest selective or whole body hypothermia in reducing the subsequent development of irreversible brain injury without untoward side effects. Data are insufficient to recommend routine use of either modest selective or whole body hypothermia after resuscitation of infants with suspected asphyxia. Further clinical trials are needed to determine which infants would benefit most and which method of cooling would be most effective.
Collapse
Affiliation(s)
- Michael Speer
- Department of Neonatology, Texas Children's Hospital, Houston, TX 77030, USA
| | | |
Collapse
|
114
|
Blackmon LR, Stark AR. Hypothermia: a neuroprotective therapy for neonatal hypoxic-ischemic encephalopathy. Pediatrics 2006; 117:942-8. [PMID: 16510680 DOI: 10.1542/peds.2005-2950] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Lillian R Blackmon
- Division of Neonatology, Department of Pediatrics, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
| | | |
Collapse
|
115
|
Tabbutt S, Ittenbach RF, Nicolson SC, Burnham N, Hittle S, Spray TL, Gaynor JW. Intracardiac temperature monitoring in infants after cardiac surgery. J Thorac Cardiovasc Surg 2006; 131:614-20. [PMID: 16515913 DOI: 10.1016/j.jtcvs.2005.09.044] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2005] [Revised: 09/08/2005] [Accepted: 09/08/2005] [Indexed: 11/20/2022]
Abstract
BACKGROUND Hyperthermia after cerebral ischemia is associated with worse neurologic outcome. Our goals were 3-fold: (1) to describe the postoperative temperature course in infants after cardiac surgery, (2) to compare intracardiac temperature monitoring with traditional monitoring in infants, and (3) to determine variables that influence the patients' temperatures. METHODS Longitudinal temperature data were collected for 100 infants undergoing cardiac surgery. Intra-atrial, nasopharyngeal, esophageal, rectal, and axillary temperatures were recorded in all patients. RESULTS The mean age at the time of operation was 128 +/- 166 days, and the mean weight was 5.1 +/- 2.4 kg. Circulatory arrest was used for 54 patients. In the operating room, the maximum intra-atrial temperature (37.5 degrees C +/- 0.6 degrees C) was significantly greater than both the simultaneous esophageal temperature (36.9 degrees C +/- 1.9 degrees C, P = .03) and nasopharyngeal temperature (36.3 degrees C +/- 2.5 degrees C, P < .001). In the cardiac intensive care unit, intra-atrial temperature was significantly greater than both axillary and rectal temperatures. During the first 24 postoperative hours, intra-atrial temperature was greater than 38 degrees C in 48 (48%) patients, rectal temperature was greater than 38 degrees C in 36 (36%) patients, and axillary temperature was greater than 38 degrees C in 7 (7%) patients. CONCLUSIONS In patients less than 2 years of age undergoing cardiac surgery requiring cardiopulmonary bypass, intra-atrial temperature peaked 4 to 6 hours after leaving the operating room. Traditional methods of temperature monitoring significantly underestimate core temperature after cardiac surgery in infants. Use of intracardiac temperature monitoring might result in avoidance of cerebral hyperthermia.
Collapse
Affiliation(s)
- Sarah Tabbutt
- Department of Pediatrics, Division of Cardiology, The Children's Hospital of Philadelphia and the University of Pennsylvania School of Medicine, Philadelphia, Pa 19104, USA.
| | | | | | | | | | | | | |
Collapse
|
116
|
Higgins RD, Raju TNK, Perlman J, Azzopardi DV, Blackmon LR, Clark RH, Edwards AD, Ferriero DM, Gluckman PD, Gunn AJ, Jacobs SE, Eicher DJ, Jobe AH, Laptook AR, LeBlanc MH, Palmer C, Shankaran S, Soll RF, Stark AR, Thoresen M, Wyatt J. Hypothermia and perinatal asphyxia: executive summary of the National Institute of Child Health and Human Development workshop. J Pediatr 2006; 148:170-175. [PMID: 16492424 DOI: 10.1016/j.jpeds.2005.12.009] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2005] [Accepted: 12/05/2005] [Indexed: 10/25/2022]
Affiliation(s)
- Rosemary D Higgins
- Pregnancy and Perinatology Branch, Center for Developmental Biology and Perinatal Medicine, National Institute of Child Health and Human Development/NIH, 6100 Executive Boulevard, MSC 7510, Bethesda, MD 20892, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
117
|
Rajadurai VS. Therapeutic Hypothermia for Neonatal Hypoxic-Ischaemic Encephalopathy. ANNALS OF THE ACADEMY OF MEDICINE, SINGAPORE 2006. [DOI: 10.47102/annals-acadmedsg.v35n1p3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
|
118
|
Jin JS, Sakaeda T, Kakumoto M, Nishiguchi K, Nakamura T, Okamura N, Okumura K. Effect of Therapeutic Moderate Hypothermia on Multi-drug Resistance Protein 1-Mediated Transepithelial Transport of Drugs. Neurol Med Chir (Tokyo) 2006; 46:321-7; discussion 327. [PMID: 16861824 DOI: 10.2176/nmc.46.321] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To clarify the effect of therapeutic moderate hypothermia on drug distribution, transepithelial transport via multi-drug resistance protein 1 (MDR1) (also called P-glycoprotein or ABCB1) was evaluated at various temperatures in vitro using LLC-GA5-COL150 cells, which were established by transfecting human MDR1 complementary deoxyribonucleic acid into kidney epithelial LLC-PK(1) cells and express MDR1 on the apical membrane. MDR1 is expressed in the blood-brain barrier to limit drug distribution to the brain by exporting exogenous substances including calcium blockers and antiarrhythmic drugs. Digoxin was used as a typical substrate, as well as the non-substrate tetracycline and paracellular marker inulin. MDR1-mediated transport of digoxin decreased at lower temperatures. Transport of tetracycline also decreased at lower temperatures, probably due to changes in membrane fluidity. However, no change was found at over 32 degrees C, suggesting that passive diffusion does not change during moderate hypothermia. The distribution of MDR1 substrates should be considered during hypothermic conditions, as the clinical outcome could be affected.
Collapse
Affiliation(s)
- Jiang-shu Jin
- Department of Hospital Pharmacy, School of Medicine, Kobe University, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan
| | | | | | | | | | | | | |
Collapse
|
119
|
Perlman J. Induced hypothermia: A novel neuroprotective treatment of neonatal encephalopathy after intrapartum hypoxia-ischemia. Curr Treat Options Neurol 2005; 7:451-8. [PMID: 16221368 DOI: 10.1007/s11940-005-0045-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The current treatment approach to an infant at risk for progression to neonatal encephalopathy after intrapartum hypoxia-ischemia is threefold: 1) early identification of the infant at highest risk for evolving brain injury based on the criteria of a sentinel event during labor, prolonged depression at birth with the need for resuscitation, and evidence of severe fetal acidemia based on a cord umbilical arterial pH less than 7 and/or a base deficit more than -16 meq per L, with early clinical and/or electroencephalogram assessment of moderate to severe encephalopathy; 2) supportive therapy instituted to maintain adequate ventilation and in particular pCO2 levels in a normal range, mean arterial blood pressure within a normal range so as to avoid perturbations in cerebral perfusion, glucose in a normal range to avoid hypoglycemia, and the judicious treatment of seizures; and 3) neuroprotection--induced hypothermia is currently the only strategy that has been rigorously evaluated in two large, multicenter randomized studies. The first study used selective cooling with a cool cap to a rectal temperature at 34.5 degrees C, and the second study used total body cooling to an esophageal temperature of 33.5 degrees C, with the temperature in both studies maintained for 72 hours. No significant side effects were noted with this degree of cooling. The combined data indicate that hypothermia is associated with a reduction in the incidence of death and/or severe disability at 18 months follow-up, with the most significant effect observed in infants who at the initiation of therapy present with modest encephalopathy and/or do not exhibit electrographic seizures.
Collapse
|
120
|
Abstract
The possibility of a therapeutic role for cerebral hypothermia during or after resuscitation from perinatal asphyxia has been a long-standing focus of research. However, early studies had limited and contradictory results. It is now known that severe hypoxia-ischemia may not cause immediate cell death, but may precipitate a complex biochemical cascade leading to the delayed development of neuronal loss. These phases include a latent phase after reperfusion, with initial recovery of cerebral energy metabolism but EEG suppression, followed by a secondary phase characterized by accumulation of cytotoxins, seizures, cytotoxic edema, and failure of cerebral oxidative metabolism from 6 to 15 h post insult. Although many of the secondary processes can be injurious, they appear to be primarily epiphenomena of the 'execution' phase of cell death. This conceptual framework allows a better understanding of the experimental parameters that determine effective hypothermic neuroprotection, including the timing of initiation of cooling, its duration and the depth of cooling attained. Moderate cerebral hypothermia initiated in the latent phase, between one and as late as 6 h after reperfusion, and continued for a sufficient duration in relation to the severity of the cerebral injury, has been consistently associated with potent, long-lasting neuroprotection in both adult and perinatal species. The results of the first large multicentre randomized trial of head cooling for neonatal encephalopathy and previous phase I and II studies now strongly suggest that prolonged cerebral hypothermia is both generally safe - at least in an intensive care setting - and can improve intact survival up to 18 months of age. Both long-term followup studies and further large studies of whole body cooling are in progress.
Collapse
|
121
|
Rutherford MA, Ward P, Malamateniou C, Malamatentiou C. Advanced MR techniques in the term-born neonate with perinatal brain injury. Semin Fetal Neonatal Med 2005; 10:445-60. [PMID: 15979420 DOI: 10.1016/j.siny.2005.05.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Magnetic resonance imaging (MRI) has become an essential tool for assessing the neonatal brain. Conventional imaging can detect patterns of injury that relate to the aetiology and timing of an insult and provide valuable information about prognosis. Sequences must always be adapted for the immature brain. Diffusion techniques improve the detection of ischaemic tissue and allow more accurate timing of an insult. Diffusion tensor imaging allows the assessment of tissue microstructure changes with normal development as well as in response to tissue injury. Diffusion tractography will further our understanding of the long-term effects of perinatal injuries on brain development, and when used in combination with clinical and functional imaging studies will allow the plasticity of the immature brain to be studied. MR angiography and venography are important adjuncts to the clinical examination, and when combined with perfusion studies can provide valuable information about vessel development following injury. Detailed vascular studies may detect inherent susceptibilities, which give rise to lesions in some babies but not others. The future for neonatal imaging is exciting; however, detailed and serial imaging of carefully chosen cohorts of infants coupled with long-term clinical follow-up are essential to ensure the clinical significance of any new findings.
Collapse
Affiliation(s)
- Mary A Rutherford
- Robert Steiner MR Unit, Imaging Sciences Department, Clinical Sciences Centre, Imperial College, Hammersmith Hospital, London, UK.
| | | | | | | |
Collapse
|
122
|
Ohmura A, Nakajima W, Ishida A, Yasuoka N, Kawamura M, Miura S, Takada G. Prolonged hypothermia protects neonatal rat brain against hypoxic-ischemia by reducing both apoptosis and necrosis. Brain Dev 2005; 27:517-26. [PMID: 15899566 DOI: 10.1016/j.braindev.2005.01.004] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2004] [Revised: 12/27/2004] [Accepted: 01/13/2005] [Indexed: 11/16/2022]
Abstract
Although hypothermia is an effective treatment for perinatal cerebral hypoxic-ischemic (HI) injury, it remains unclear how long and how deep we need to maintain hypothermia to obtain maximum neuroprotection. We examined effects of prolonged hypothermia on HI immature rat brain and its protective mechanisms using the Rice-Vannucci model. Immediately after the end of hypoxic exposure, the pups divided into a hypothermia group (30 degrees C) and a normothermia one (37 degrees C). Rectal temperature was maintained until they were sacrificed at each time point before 72h post HI. Prolonged hypothermia significantly reduced macroscopic brain injury compared with normothermia group. Quantitative analysis of cell death using H&E-stained sections revealed the number of both apoptotic and necrotic cells was significantly reduced by hypothermia after 24h post HI. Hypothermia seemed to decrease the number of TUNEL-positive cells. Immunohistochemistry and Western blot showed that prolonged hypothermia suppressed cytochrome c release from mitochondria to cytosol and activation of both caspase-3 and calpain in cortex, hippocampus, thalamus and striatum throughout the experiment. These results showed that prolonged hypothermia significantly reduced neonatal brain injury even when it was started after HI insult. Our results suggest that prolonged hypothermia protects neonatal brain after HI by reducing both apoptosis and necrosis.
Collapse
Affiliation(s)
- Akiko Ohmura
- Department of Pediatrics, Akita University School of Medicine, 1-1-1 Honda, Akita, 010-8543, Japan
| | | | | | | | | | | | | |
Collapse
|
123
|
Rutherford MA, Azzopardi D, Whitelaw A, Cowan F, Renowden S, Edwards AD, Thoresen M. Mild hypothermia and the distribution of cerebral lesions in neonates with hypoxic-ischemic encephalopathy. Pediatrics 2005; 116:1001-6. [PMID: 16199715 DOI: 10.1542/peds.2005-0328] [Citation(s) in RCA: 144] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Hypothermia induced by whole-body cooling (WBC) and selective head cooling (SHC) both reduce brain injury after hypoxia-ischemia in newborn animals, but it is not known how these treatments affect the incidence or pattern of brain injury in human newborns. To assess this, 14 term infants with hypoxic-ischemic encephalopathy (HIE) treated with SHC, 20 infants with HIE treated with WBC, and 52 noncooled infants with HIE of similar severity were studied with magnetic resonance imaging in the neonatal period. Infants fulfilling strict criteria for HIE were recruited into the study after assessment of an amplitude-integrated electroencephalography (aEEG). Cooling was commenced within 6 hours of birth and continued for 48 to 72 hours. Hypothermia was not associated with unexpected or unusual lesions, and the prevalence of intracranial hemorrhage was similar in all 3 groups. Both modes of hypothermia were associated with a decrease in basal ganglia and thalamic lesions, which are predictive of abnormal outcome. This decrease was significant in infants with a moderate aEEG finding but not in those with a severe aEEG finding. A decrease in the incidence of severe cortical lesions was seen in the infants treated with SHC.
Collapse
Affiliation(s)
- Mary A Rutherford
- Imaging Sciences Department, Imperial College, Hammersmith Hospital, London, United Kingdom.
| | | | | | | | | | | | | |
Collapse
|
124
|
Sisman J, Campbell DE, Brion LP. Amplitude-integrated EEG in preterm infants: maturation of background pattern and amplitude voltage with postmenstrual age and gestational age. J Perinatol 2005; 25:391-6. [PMID: 15815708 DOI: 10.1038/sj.jp.7211291] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Amplitude-integrated electroencephalogram (aEEG) is a single channel EEG recorded from two parietal electrodes. The objective of this study was to test the hypothesis that aEEG maturation follows postmenstrual age (PMA) irrespective of gestational age (GA). METHODS We recruited inborn infants with a GA <33 weeks and without evidence of neurologic anomaly. Serial aEEG recordings were assessed for: presence of continuous activity and mature sleep-wake cycling (SWC); low base voltage (V), that is, the lowest amplitude margin; high base V, that is, the most common amplitude margin; upper high V, that is, upper margin during highest activity; and span, that is, the difference between upper high and simultaneous high base V. Statistical analysis included logistic regression and repeated measures analysis of variance. RESULTS We obtained 119 aEEG recordings in 31 preterm infants (GA 25 to 32 weeks; birth weight 600 to 1704 g, PMA 25 to 35 weeks). The frequency of mature SWC increased with PMA independent of GA, while the frequency of continuity increased with PMA and was higher in extremely preterm infants after correcting for PMA. Low base and high base V increased with PMA, while span and upper high V significantly decreased with PMA. In addition, high base V was higher in extremely preterm infants after correcting for PMA. CONCLUSIONS In preterm infants aEEG matures predominantly with PMA. Our data suggest that some aspects of aEEG maturation are enhanced, rather than inhibited by extremely preterm birth. These data suggest that aEEG in preterm infants may need to be analyzed by comparing results with standards of similar PMA and GA.
Collapse
Affiliation(s)
- Jülide Sisman
- Albert Einstein College of Medicine, Children's Hospital at Montefiore, Bronx, NY 10461, USA
| | | | | |
Collapse
|
125
|
Sola A, Wen TC, Hamrick SEG, Ferriero DM. Potential for protection and repair following injury to the developing brain: a role for erythropoietin? Pediatr Res 2005; 57:110R-117R. [PMID: 15817504 DOI: 10.1203/01.pdr.0000159571.50758.39] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Perinatal brain injury is a major contributor to perinatal morbidity and mortality, and a considerable number of these children will develop long term neurodevelopmental disabilities. Despite the severe clinical and socio-economic significance and the advances in neonatal care over the past twenty years, no therapy yet exists that effectively prevents or ameliorates detrimental neurodevelopmental effects in cases of perinatal/neonatal brain injury. Our objective is to review recent evidence in relation to the pervading hypothesis for targeting time-dependent molecular and cellular repair mechanisms in the developing brain. In addition we review several potential neuroprotective strategies specific to the developing nervous system, with a focus on erythropoietin (Epo) because of its potential role in protection as well as repair.
Collapse
Affiliation(s)
- Augusto Sola
- Division of Neonatal-Perinatal Medicine, Emory University School of Medicine, Atlanta, Georgia 30322, USA.
| | | | | | | |
Collapse
|
126
|
van Rooij LGM, Toet MC, Osredkar D, van Huffelen AC, Groenendaal F, de Vries LS. Recovery of amplitude integrated electroencephalographic background patterns within 24 hours of perinatal asphyxia. Arch Dis Child Fetal Neonatal Ed 2005; 90:F245-51. [PMID: 15846017 PMCID: PMC1721875 DOI: 10.1136/adc.2004.064964] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVE To assess the time course of recovery of severely abnormal initial amplitude integrated electroencephalographic (aEEG) patterns (flat trace (FT), continuous low voltage (CLV), or burst suppression (BS)) in full term asphyxiated neonates, in relation to other neurophysiological and neuroimaging findings and neurodevelopmental outcome. METHODS A total of 190 aEEGs of full term infants were reviewed. The neonates were admitted within 6 hours of birth to the neonatal intensive care unit because of perinatal asphyxia, and aEEG recording was started immediately. In all, 160 infants were included; 65 of these had an initial FT or CLV pattern and 25 an initial BS pattern. Neurodevelopmental outcome was assessed using a full neurological examination and the Griffiths' mental developmental scale. RESULTS In the FT/CLV group, the background pattern recovered to continuous normal voltage within 24 hours in six of the 65 infants (9%). All six infants survived the neonatal period; one had a severe disability, and five were normal at follow up. In the BS group, the background pattern improved to normal voltage in 12 of the 25 infants (48%) within 24 hours. Of these infants, one died, five survived with moderate to severe disability, two with mild disability, and four were normal. The patients who did not recover within 24 hours either died in the neonatal period or survived with a severe disability. CONCLUSION In this study there was a small group of infants who presented with a severely abnormal aEEG background pattern within six hours of birth, but who achieved recovery to a continuous normal background pattern within the first 24 hours. Sixty one percent of these infants survived without, or with a mild, disability.
Collapse
Affiliation(s)
- L G M van Rooij
- Department of Neonatology, Wilhelmina Children's Hospital, University Medical Centre Utrecht, KE 04.123.1, PO Box 85090, 3508 AB Utrecht, The Netherlands
| | | | | | | | | | | |
Collapse
|
127
|
Gerrits LC, Battin MR, Bennet L, Gonzalez H, Gunn AJ. Epileptiform activity during rewarming from moderate cerebral hypothermia in the near-term fetal sheep. Pediatr Res 2005; 57:342-6. [PMID: 15585677 DOI: 10.1203/01.pdr.0000150801.61188.5f] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Moderate hypothermia is consistently neuroprotective after hypoxic-ischemic insults and is the subject of ongoing clinical trials. In pilot studies, we observed rebound seizure activity in one infant during rewarming from a 72-h period of hypothermia. We therefore quantified the development of EEG-defined seizures during rewarming in an experimental paradigm of delayed cooling for cerebral ischemia. Moderate cerebral hypothermia (n=9) or sham cooling (n=13) was initiated 5.5 h after reperfusion from a 30-min period of bilateral carotid occlusion in near-term fetal sheep and continued for 72 h after the insult. During spontaneous rewarming, fetal extradural temperature rose from 32.5 +/- 0.6 degrees C to control levels (39.4 +/- 0.1 degrees C) in 47 +/- 6 min. Carotid blood flow and mean arterial blood pressure increased transiently during rewarming. The cooling group showed a significant increase in electrical seizure events 2, 3, and 5 h after rewarming, maximal at 2 h (2.9 +/- 1.2 versus 0.5 +/- 0.5 events/h; p <0.05). From 6 h after rewarming, there was no significant difference between the groups. Individual seizures were typically short (28.8 +/- 5.8 s versus 29.0 +/- 6.8 s in sham cooled; NS), and of modest amplitude (35.9 +/- 2.8 versus 38.8 +/- 3.4 microV; NS). Neuronal loss in the parasagittal cortex was significantly reduced in the cooled group (51 +/- 9% versus 91 +/- 5%; p <0.002) and was not correlated with rebound epileptiform activity. In conclusion, rapid rewarming after a prolonged interval of therapeutic hypothermia can be associated with a transient increase in epileptiform events but does not seem to have significant adverse implications for neural outcome.
Collapse
|
128
|
Gluckman PD, Wyatt JS, Azzopardi D, Ballard R, Edwards AD, Ferriero DM, Polin RA, Robertson CM, Thoresen M, Whitelaw A, Gunn AJ. Selective head cooling with mild systemic hypothermia after neonatal encephalopathy: multicentre randomised trial. Lancet 2005; 365:663-70. [PMID: 15721471 DOI: 10.1016/s0140-6736(05)17946-x] [Citation(s) in RCA: 1426] [Impact Index Per Article: 75.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND Cerebral hypothermia can improve outcome of experimental perinatal hypoxia-ischaemia. We did a multicentre randomised controlled trial to find out if delayed head cooling can improve neurodevelopmental outcome in babies with neonatal encephalopathy. METHODS 234 term infants with moderate to severe neonatal encephalopathy and abnormal amplitude integrated electroencephalography (aEEG) were randomly assigned to either head cooling for 72 h, within 6 h of birth, with rectal temperature maintained at 34-35 degrees C (n=116), or conventional care (n=118). Primary outcome was death or severe disability at 18 months. Analysis was by intention to treat. We examined in two predefined subgroup analyses the effect of hypothermia in babies with the most severe aEEG changes before randomisation--ie, severe loss of background amplitude, and seizures--and those with less severe changes. FINDINGS In 16 babies, follow-up data were not available. Thus in 218 infants (93%), 73/110 (66%) allocated conventional care and 59/108 (55%) assigned head cooling died or had severe disability at 18 months (odds ratio 0.61; 95% CI 0.34-1.09, p=0.1). After adjustment for the severity of aEEG changes with a logistic regression model, the odds ratio for hypothermia treatment was 0.57 (0.32-1.01, p=0.05). No difference was noted in the frequency of clinically important complications. Predefined subgroup analysis suggested that head cooling had no effect in infants with the most severe aEEG changes (n=46, 1.8; 0.49-6.4, p=0.51), but was beneficial in infants with less severe aEEG changes (n=172, 0.42; 0.22-0.80, p=0.009). INTERPRETATION These data suggest that although induced head cooling is not protective in a mixed population of infants with neonatal encephalopathy, it could safely improve survival without severe neurodevelopmental disability in infants with less severe aEEG changes.
Collapse
Affiliation(s)
- Peter D Gluckman
- The Liggins Institute, University of Auckland, Auckland, New Zealand
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
129
|
Abstract
Studies in encephalopathic infants have demonstrated a brief phase of normal cerebral energetics following hypoxia-ischaemia prior to development of delayed energy failure. In experimental models, mild hypothermia has shown a consistent neuroprotective action, although its efficacy is critically dependent on the severity of the primary insult, the delay in initiating cooling, and the duration and depth of hypothermia. Early electroencephalographic assessment of encephalopathic infants has the potential to provide objective information about the preceding insult, aiding the selection of infants for enrollment to clinical trials. Preliminary results from a large randomised trial of selective head cooling suggest that early intervention can lead to significantly improved outcome in a subgroup of encephalopathic infants with intermediate electroencephalographic abnormalities. Further research in established experimental models is essential to improve the identification of suitable infants for treatment, to investigate the importance of variations in regional brain temperature, and to examine the therapeutic potential of hypothermia combined with other neuroprotective agents.
Collapse
Affiliation(s)
- John S Wyatt
- Department of Paediatrics and Child Health, Royal Free and University College London, 5 University Street, London WC1E 6JJ, United Kingdom.
| | | |
Collapse
|
130
|
Eicher DJ, Wagner CL, Katikaneni LP, Hulsey TC, Bass WT, Kaufman DA, Horgan MJ, Languani S, Bhatia JJ, Givelichian LM, Sankaran K, Yager JY. Moderate hypothermia in neonatal encephalopathy: safety outcomes. Pediatr Neurol 2005; 32:18-24. [PMID: 15607599 DOI: 10.1016/j.pediatrneurol.2004.06.015] [Citation(s) in RCA: 201] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2003] [Accepted: 06/15/2004] [Indexed: 11/20/2022]
Abstract
Hypoxic-ischemic injury may cause multisystem organ damage with significant aberrations in clotting, renal, and cardiac functions. Systemic hypothermia may aggravate these medical conditions, such as bradycardia and increased clotting times, and very little safety data in neonatal hypoxic-ischemic injury is available. This study reports a multicenter, randomized, controlled pilot trial of moderate systemic hypothermia (33 degrees C) vs normothermia (37 degrees C) for 48 hours in infants with neonatal encephalopathy instituted within 6 hours of birth or hypoxic-ischemic event. The best outcome measures of safety were determined, comparing rates of adverse events between normothermia and hypothermia groups. A total of 32 hypothermia and 33 normothermia neonates were enrolled in seven centers. Adverse events and serious adverse effects were collected by the study team during the hospital admission, monitored by an independent study monitor, and reported to Institutional Review Boards and the Data and Safety Monitoring Committee. The following adverse events were observed significantly more commonly in the hypothermia group: more frequent bradycardia and lower heart rates during the period of hypothermia, longer dependence on pressors, higher prothrombin times, and lower platelet counts with more patients requiring plasma and platelet transfusions. Seizures as an adverse event were more common in the hypothermia group. These observed side effects of 48 hours of moderate systemic hypothermia were of mild to moderate severity and manageable with minor interventions.
Collapse
Affiliation(s)
- Dorothea J Eicher
- Department of Pediatrics, Medical University of South Carolina, Charleston, South Carolina 29425, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
131
|
Inder TE, Hunt RW, Morley CJ, Coleman L, Stewart M, Doyle LW, Jacobs SE. Randomized trial of systemic hypothermia selectively protects the cortex on MRI in term hypoxic-ischemic encephalopathy. J Pediatr 2004; 145:835-7. [PMID: 15580212 DOI: 10.1016/j.jpeds.2004.07.034] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Twenty-six infants with hypoxic-ischemic encephalopathy (HIE) were randomized to normothermia or to systemic hypothermia. The hypothermia group had less cortical gray matter signal abnormality on magnetic resonance imaging (MRI) (1/12 vs 7/14 infants in the normothermic group; P = .036), which may indicate differing regional benefit from systemic hypothermia.
Collapse
Affiliation(s)
- Terrie E Inder
- Division of Newborn Services, Royal Women's Hospital, Neonatal Neurology, Royal Children's Hospital, Melbourne, Australia.
| | | | | | | | | | | | | |
Collapse
|
132
|
Abstract
The brain, unlike many tissues, has a limited capacity for self-repair and so there has been great interest in the possibility of transplanting neural cells to replace those lost through injury or disease. Encouraging research in humans is already underway examining the possibility of neural cell replacement in adult neurodegenerative conditions such as Parkinson's disease and Huntington disease. In addition, experiments exploring neural stem cell replacement in rodent models of acute stroke, demyelination and spinal cord injury have demonstrated functional improvements in treated animals. When considering perinatal neural stem cell therapy, it should not be overlooked that the immature, developing brain might provide a more favourable environment for stem cell integration. However, considerable advances need to be made both in understanding the basic biology of neural stem cells, including the instructive signals that determine their proliferation and differentiation, and in characterising their responses when transplanted in a damaged or diseased area of the brain.
Collapse
Affiliation(s)
- Nigel L Kennea
- Weston Laboratory, Institute of Reproductive and Developmental Biology, Division of Paediatrics, Obstetrics and Gynaecology, Imperial College, London W12 0NN, UK
| | | |
Collapse
|
133
|
Abstract
Perinatal brain injury in the term infant is a relatively uncommon event. The principal lesions are intracranial hemorrhage including subarachnoid, subdural, intraparenchymal, intraventricular, focal cerebral infarction and hypoxic ischemic cerebral injury secondary to intrapartum hypoxia-ischemia. Both intracranial hemorrhage and focal cerebral infarction are invariably identified at the time of clinical symptoms, ie, seizures or apnea. This clearly limits the potential for prevention. The mechanisms contributing to brain injury secondary to intrapartum hypoxia-ischemia have become more clearly defined. Secondary or reperfusion injury is potentially amenable to neuroprotective strategies. Modest hypothermia is one such therapy that has been studied in high-risk newborn infants with some initial success. Future studies need to focus on additional neuroprotective strategies.
Collapse
Affiliation(s)
- Jeffrey M Perlman
- Division of Neonatology, Department of Pediatrics, Joan and Sanford I. Weill Medical College and Graduate School of Medical Sciences at Cornell University, New York, NY 10021, USA.
| |
Collapse
|
134
|
Abstract
This article will define the concept of fetal/neonatal inflammatory response, and examine the complex interaction between inflammation and neurotoxicity. There appear to be important interactions between infection/inflammation and hypoxia-ischaemia leading to cytokine release and subsequent brain injury. This article will also define adverse outcome and summarize the complexities inherent to neurodevelopmental assessment. Finally, this article will investigate the currently available evidence suggesting a link between inflammatory response and adverse neurodevelopmental outcome, and focus on those variables that need further study: timing and nature of the infectious/inflammatory process; established and new anti-insult strategies; morbidity in organs other than the brain; genetic influences; and environmental factors.
Collapse
Affiliation(s)
- L Cornette
- Peter Congdon Neonatal Unit, Clarendon Wing - C Floor, Leeds General Infirmary, Great George Street, Leeds LS2 9NS, UK.
| |
Collapse
|
135
|
Abstract
An enhanced understanding of the cellular characteristics contributing to ongoing brain injury following intrapartum hypoxia-ischemia has resulted in the implementation of targeted neuroprotective strategies in the newborn period. This review briefly covers the pathogenesis of hypoxic-ischemic injury with an emphasis on reperfusion injury; the role of magnetic resonance imaging in the detection of such injury, and focuses on potential strategies both supportive and neuroprotective to prevent ongoing injury with a specific emphasis on modest hypothermia.
Collapse
Affiliation(s)
- Lina Shalak
- Department of Pediatrics, Southwestern Medical Center, University of Texas, 5323 Harry Hines Blvd., Dallas, TX 75390, USA
| | | |
Collapse
|
136
|
Morris MC, Nadkarni VM, Ward FR, Nelson RM. Exception from informed consent for pediatric resuscitation research: community consultation for a trial of brain cooling after in-hospital cardiac arrest. Pediatrics 2004; 114:776-81. [PMID: 15342853 DOI: 10.1542/peds.2004-0482] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVES When prospective informed consent is not feasible, clinical research that presents more than minimal risk can proceed only after a community consultation and public disclosure process and the granting of exception from informed consent from the federal government. The applicability of exception from informed consent to pediatric resuscitation research has not been described. The objectives of this study were 1) to perform a community consultation and public disclosure process specific to a trial of induced hypothermia immediately after pediatric cardiac arrest and 2) to determine the applicability of exception from informed consent to randomized, controlled trials of emergency interventions after resuscitation from inpatient pediatric cardiac arrest. METHODS Focus groups, information sheets with options for written responses, posted notices, e-mails, and telephone conversations with parents of critically ill children and hospital staff were conducted at a tertiary care children's hospital. Data were stored, organized, and retrieved using NVivo qualitative analysis software (QSR International). RESULTS In focus groups (n = 8), parents (n = 23) and hospital staff (n = 33) concluded that prospective informed consent is not feasible for a trial of induced hypothermia after inpatient pediatric cardiac arrest. Focus group participants endorsed exception from informed consent for a trial of induced hypothermia but only if study information is easily available prospectively and if all parents have an explicit opportunity to decline participation in a verbal conversation before study enrollment. Separate from and without knowledge of the focus group results, 7 (100%) of 7 parents of past or current patients and 21 (50%) of 42 hospital staff who provided written opinions endorsed exception from informed consent for this study. Five (12%) of 42 hospital staff opposed, and 16 (38%) of 42 were neutral. In telephone conversations, 14 (70%) of 20 parents of children who were previously resuscitated from cardiac arrest endorsed exception from informed consent for this study, 3 (15%) of 20 opposed, and 3 (15%) of 20 were unsure. CONCLUSIONS Community consultation for inpatient resuscitation research can be conducted in a children's hospital, with hospital staff and parents of patients as the relevant community. Exception from informed consent is necessary and appropriate for a randomized trial of induced hypothermia begun within 30 minutes after pediatric cardiac arrest. A process in which families are informed prospectively and have a pre-enrollment option to decline participation will likely be acceptable to families, health care providers, and the institution.
Collapse
Affiliation(s)
- Marilyn C Morris
- Department of Anesthesia and Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
| | | | | | | |
Collapse
|
137
|
Jiang ZD, Yin R, Shao XM, Wilkinson AR. Brain-stem auditory impairment during the neonatal period in term infants after asphyxia: dynamic changes in brain-stem auditory evoked response to clicks of different rates. Clin Neurophysiol 2004; 115:1605-15. [PMID: 15203061 DOI: 10.1016/j.clinph.2004.02.017] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/21/2004] [Indexed: 11/15/2022]
Abstract
OBJECTIVE To explore dynamic changes in brain-stem auditory electrophysiology during the neonatal period in term infants after perinatal asphyxia. METHODS Sixty-eight term newborn infants who suffered asphyxia were studied on days 1, 3, 5, 7, 14 and 30 after birth. Brain-stem auditory evoked response (BAER) was recorded with clicks, delivered at 21, 51 and 91 s(-1) and > or =40 dB above BAER threshold of each subject. RESULTS During the neonatal period wave I latency in the infants after asphyxia increased slightly while later BAER components changed more significantly. On the first day after birth wave III and V latencies and I-V and III-V intervals increased significantly at all rates of clicks (ANOVA P<0.01-0.001). On day 3, the latencies and intervals increased further. III-V/I-III interval ratio increased at 51 and 91 s(-1), suggesting a relatively more significant increase in III-V interval than in I-III interval at higher rates. Thereafter, wave III and V latencies and all intervals decreased progressively, although these BAER variables were still significantly longer than in normal controls on days 5 and 7 (P<0.05-0.001) On day 30, all latencies and intervals approached near normal values, with a slight increase in wave V latency and I-V and III-V intervals at 51 and 91 s(-1). CONCLUSIONS Perinatal asphyxia has a major effect on central auditory function, resulting in acute impairment. The impairment progresses during the first 3 days and then tends towards recovery. By 1 month the impaired auditory function has largely returned to normal. Significant increase in click rates can moderately improve the detection of auditory impairment. SIGNIFICANCE After perinatal asphyxia early detection of hypoxic-ischaemic damage to the central auditory system and initialisation of neuroprotective and therapeutic measures during the first hours after birth are critical to prevent or reduce deterioration of central impairment.
Collapse
Affiliation(s)
- Ze D Jiang
- Children's Hospital, Shanghai Medical University, Shanghai, China.
| | | | | | | |
Collapse
|
138
|
Squier W, Cowan FM. The value of autopsy in determining the cause of failure to respond to resuscitation at birth. ACTA ACUST UNITED AC 2004; 9:331-45. [PMID: 15251149 DOI: 10.1016/j.siny.2004.01.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Autopsy is invaluable in identifying the causes of severe depression and very low Apgar score after birth and in assessing contributory conditions. Brain scans are increasingly used in the care of neonates who fail to respond to resuscitation at birth but their interpretation depends on the information gained from sound neuropathological studies. Asphyxia, both acute intrapartum asphyxia and chronic asphyxia, is an important cause of low Apgar scores. The gestational age and the nature of the asphyxial insult both have a profound influence on the ultimate pattern of injury. Asphyxia in the preterm brain tends to damage preferentially the white matter but some white matter damage is also seen in many infants who have an hypoxia-ischaemic insult at term though the predominant site of injury is to the central grey matter. The nature of the cellular damage and reactive change seen at autopsy is described. There is an association between low Apgar scores and intrauterine exposure to infection and maternal pyrexia. Detailed autopsy examination should include the search for infection. The placenta, cord and membranes should be examined in view of the mounting evidence of the association between intrauterine infection of the placenta and fetal membranes and prenatal brain damage. Additionally, the presence of placental thrombosis and infarction should be sought in relation to focal and global injury in the full term infant. Acquired prepartum lesions rarely cause the infant to present with a low Apgar score. The exception to this is severe damage to the brainstem and basal ganglia. Traumatic injury to the brain is now much less common than in previous decades. Subdural haemorrhage occurs more frequently than intraventricular or subarachnoid haemorrhage. Instrumental and assisted deliveries are associated with an increased incidence of subdural haemorrhage though these rarely cause significant long term damage. Careful autopsy, particularly of the neck and paravertebral tissues, spinal cord, brainstem and nerve roots is important where trauma is suspected. Tearing of nerve roots or fibre bundles in the spinal cord is readily demonstrated under the microscope using immunocytochemistry to beta-amyloid precursor protein. Disorders of the spinal cord, peripheral nerve and muscle as well as some metabolic diseases may cause a baby to be both floppy and weak. Metabolic disease, including peroxisomal disorders, non-ketotic hyperglycinaemia, lipid and glycogen storage disorders and mitochondrial diseases may cause profound hypotonia and respiratory failure at birth or shortly afterwards.
Collapse
MESH Headings
- Apgar Score
- Asphyxia Neonatorum/diagnosis
- Asphyxia Neonatorum/mortality
- Asphyxia Neonatorum/pathology
- Autopsy
- Birth Injuries/diagnosis
- Birth Injuries/mortality
- Birth Injuries/pathology
- Brain/abnormalities
- Brain/pathology
- Brain Diseases/diagnosis
- Brain Diseases/mortality
- Brain Diseases/pathology
- Cause of Death
- Cerebral Hemorrhage/diagnosis
- Cerebral Hemorrhage/mortality
- Cerebral Hemorrhage/pathology
- Humans
- Hypoxia-Ischemia, Brain/diagnosis
- Hypoxia-Ischemia, Brain/mortality
- Hypoxia-Ischemia, Brain/pathology
- Infant, Newborn
- Infant, Newborn, Diseases/diagnosis
- Infant, Newborn, Diseases/mortality
- Infant, Newborn, Diseases/pathology
- Infections/diagnosis
- Infections/mortality
- Infections/pathology
- Magnetic Resonance Imaging
- Metabolism, Inborn Errors/diagnosis
- Metabolism, Inborn Errors/mortality
- Metabolism, Inborn Errors/pathology
- Neuromuscular Diseases/congenital
- Neuromuscular Diseases/diagnosis
- Neuromuscular Diseases/mortality
- Neuromuscular Diseases/pathology
- Resuscitation
- Treatment Failure
Collapse
Affiliation(s)
- Waney Squier
- Department of Neuropathology, Radcliffe Infirmary, Oxford OX2 6HE, UK.
| | | |
Collapse
|
139
|
ter Horst HJ, Sommer C, Bergman KA, Fock JM, van Weerden TW, Bos AF. Prognostic significance of amplitude-integrated EEG during the first 72 hours after birth in severely asphyxiated neonates. Pediatr Res 2004; 55:1026-33. [PMID: 15155870 DOI: 10.1203/01.pdr.0000127019.52562.8c] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Amplitude-integrated EEG (aEEG) is used to select patients for neuroprotective therapy after perinatal asphyxia because of its prognostic accuracy within several hours after birth. We aimed to determine the natural course of aEEG patterns during the first 72 h of life, in relation to neurologic outcome, in a group of severely asphyxiated term infants. Thirty infants, admitted to our neonatal intensive care unit from October 1998 until February 2001, were studied retrospectively. The aEEG traces obtained during the first 72 h after birth were assessed by pattern recognition: continuous normal voltage (CNV), discontinuous normal voltage (DNV), burst suppression (BS), continuous low voltage, and flat trace. Epileptic activity was also determined. The course of aEEG patterns was examined in relation to neurologic findings at 24 mo. Initially, 17 of 30 infants had severely abnormal aEEG patterns (BS or worse), which changed spontaneously to normal voltage patterns (CNV, DNV) in 7 within 48 h. The sooner the abnormalities on aEEG disappeared, the better the prognosis. The likelihood ratio of BS or worse for adverse outcome was 2.7 (95% confidence interval 1.4-5.0) between 0 and 6 h and increased to a highest value of 19 (95% confidence interval 2.8-128) between 24 and 36 h; after 48 h, it was not significant. Normal voltage patterns (CNV and DNV) up to 48 h of life were predictive for normal neurologic outcomes (negative likelihood ratios <0.3). Our findings indicate that the course of aEEG patterns adds to the prognostic value of aEEG monitoring in asphyxiated infants. Spontaneous recovery of severely abnormal aEEG patterns is not uncommon.
Collapse
Affiliation(s)
- Hendrik J ter Horst
- Department of Paediatrics, Division of Neonatology, Beatrix Children's Hospital, University Hospital, Hanzeplein 1, 9713 GZ Groningen, The Netherlands
| | | | | | | | | | | |
Collapse
|
140
|
Horan M, Ichiba S, Firmin RK, Killer HM, Edwards D, Azzopardi D, Hodge R, Kotecha S, Field D. A pilot investigation of mild hypothermia in neonates receiving extracorporeal membrane oxygenation (ECMO). J Pediatr 2004; 144:301-8. [PMID: 15001932 DOI: 10.1016/j.jpeds.2003.11.034] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
OBJECTIVE To investigate the safety and feasibility of using mild hypothermia in neonates receiving extracorporeal membrane oxygenation (ECMO). Study design A prospective, nonrandomized pilot study of 25 neonates referred for ECMO. Whole body cooling was achieved by adjustment of the temperature of the extracorporeal circuit water bath. Five groups (N=5 per group) were each studied for the first 5 days of ECMO. The first group was maintained at 37 degrees C throughout the study period. Subsequent groups were cooled to 36 degrees C, to 35 degrees C, and, finally, to 34 degrees C, respectively, for 24 hours and the final group to 34 degrees C for 48 hours before being rewarmed to 37 degrees C. Patients were carefully assessed clinically and biologically. In addition to routine laboratory tests, cytokines (IL-6 and IL-8), complement (C3a), and molecular markers of coagulation (thrombin/antithrombin III [TAT], antithrombin III, and plasmin-alpha2plasminogen) were measured. RESULTS No major clinical or circuit problems were noted during cooling or rewarming. In particular, there were no problems of bleeding or cardiac arrhythmia. No significant difference was found between groups in terms of molecular markers of coagulation, complement, cytokines, and platelet transfusions. CONCLUSIONS Applying mild hypothermia (34 degrees C) for 24 or 48 hours to neonates receiving ECMO is both feasible and safe.
Collapse
Affiliation(s)
- Marie Horan
- Department of Child Health, University of Leicester, London United Kingdom
| | | | | | | | | | | | | | | | | |
Collapse
|
141
|
Polderman KH. Application of therapeutic hypothermia in the ICU: opportunities and pitfalls of a promising treatment modality. Part 1: Indications and evidence. Intensive Care Med 2004; 30:556-75. [PMID: 14767591 DOI: 10.1007/s00134-003-2152-x] [Citation(s) in RCA: 216] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2003] [Accepted: 12/18/2003] [Indexed: 01/04/2023]
Abstract
OBJECTIVE Hypothermia has been used for medicinal purposes since ancient times. This paper reviews the current potential clinical applications for mild hypothermia (32-35 degrees C). DESIGN AND SETTING Induced hypothermia is used mostly to prevent or attenuate neurological injury, and has been used to provide neuroprotection in traumatic brain injury, cardiopulmonary resuscitation, stroke, and various other disorders. The evidence for each of these applications is discussed, and the mechanisms underlying potential neuroprotective effects are reviewed. Some of this evidence comes from animal models, and a brief overview of these models and their limitations is included in this review. RESULTS The duration of cooling and speed of re-warming appear to be key factors in determining whether hypothermia will be effective in preventing or mitigating neurological injury. Some other potential usages of hypothermia, such as its use in the peri-operative setting and its application to mitigate cardiac injury following ischemia and reperfusion, are also discussed. CONCLUSIONS Although induced hypothermia appears to be a highly promising treatment, it should be emphasized that it is associated with a number of potentially serious side effects, which may negate some or all of its potential benefits. Prevention and/or early treatment of these complications are the key to successful use of hypothermia in clinical practice. These side effects, as well as various physiological changes induced by cooling, are discussed in a separate review.
Collapse
Affiliation(s)
- Kees H Polderman
- Department of Intensive Care, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam, The Netherlands.
| |
Collapse
|
142
|
Jiang ZD, Brosi DM, Wang J, Xu X, Chen GQ, Shao XM, Wilkinson AR. Time course of brainstem pathophysiology during first month in term infants after perinatal asphyxia, revealed by MLS BAER latencies and intervals. Pediatr Res 2003; 54:680-7. [PMID: 12869665 DOI: 10.1203/01.pdr.0000084084.62571.12] [Citation(s) in RCA: 36] [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
Dynamic changes in electrophysiology of brainstem auditory neurons during the first month after birth were studied in 51 term infants after perinatal asphyxia using maximum length sequence brainstem auditory evoked responses. The responses were recorded on d 1, 3, 5, 7, 10, 15, and 30 after birth. On d 1, wave III and V latencies and all interpeak intervals increased significantly at all repetition rates of clicks used (91-910/s), especially the higher rates (ANOVA, p < 0.05-0.0001). On d 3, all these latencies and intervals increased further and differed more significantly from the normal control subjects. Thereafter, the latencies and intervals decreased progressively. On d 7, wave V latency and all intervals still differed significantly from the control subjects. These dynamic changes were more significant at higher rates of clicks than at lower rates. On d 10 and 15, all intervals decreased significantly. On d 30, all wave latencies decreased to the values in the normal control subjects on the same day. The intervals also approached normal values, although the III-V and I-V intervals still increased slightly. These results indicate that hypoxic-ischemic brain damage persists during the first week, with a peak on d 3, and recovers progressively thereafter. By 1 mo, the damage has largely returned to normal. Maximum length sequence brainstem auditory evoked responses results correlated well with the stage of hypoxic-ischemic encephalopathy during the first week. The present study revealed a general time course of brainstem pathophysiology after asphyxia, although there were individual variations. Our findings can be used as a reference to monitor cerebral function and help judge the value of neuroprotective or therapeutic interventions. The first week, particularly the first 3 d, is a critical period of hypoxic-ischemic brain damage, and early intervention may prevent or reduce deterioration of the damage.
Collapse
Affiliation(s)
- Ze D Jiang
- Neonatal Unit, Department of Paediatrics, University of Oxford, John Radcliffe Hospital, Headington, Oxford OX3 9DU, United Kingdom.
| | | | | | | | | | | | | |
Collapse
|
143
|
Jensen A, Garnier Y, Middelanis J, Berger R. Perinatal brain damage--from pathophysiology to prevention. Eur J Obstet Gynecol Reprod Biol 2003; 110 Suppl 1:S70-9. [PMID: 12965093 DOI: 10.1016/s0301-2115(03)00175-1] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Children undergoing perinatal brain injury often suffer from the dramatic consequences of this misfortune for the rest of their lives. Despite the severe clinical and socio-economic significance, no effective clinical strategies have yet been developed to counteract this condition. This review describes the pathophysiological mechanisms that are implicated in perinatal brain injury. These include the acute breakdown of neuronal membrane potential followed by the release of excitatory amino acids such as glutamate and aspartate. Glutamate binds to postsynaptically located glutamate receptors that regulate calcium channels. The resulting calcium influx activates proteases, lipases and endonucleases which in turn destroy the cellular skeleton. The acute lack of cellular energy during ischemia induces almost complete inhibition of cerebral protein biosynthesis. Once the ischemic period is over, protein biosynthesis returns to preischemic levels in non-vulnerable regions of the brain, while in more vulnerable areas it remains inhibited. A second wave of neuronal cell damage occurs during the reperfusion phase induced by the postischemic release of oxygen radicals, synthesis of nitric oxide (NO), inflammatory reactions and an imbalance between the excitatory and inhibitory neurotransmitter systems. Clinical studies have shown that intrauterine infection increases the risk of periventricular white matter damage especially in the immature fetus. This damage may be mediated by cardiovascular effects of endotoxins leading to cerebral hypoperfusion and by activation of apoptotic pathways in oligodendrocyte progenitors through the release of pro-inflammatory cytokines. Knowledge of these pathophysiological mechanisms has enabled scientists to develop new therapeutic strategies which have been shown to be neuroprotective in animal experiments. The potential of such therapies is discussed here, particularly the promising effects of postischemic induction of mild cerebral hypothermia, the application of the calcium-antagonist flunarizine and the administration of magnesium.
Collapse
Affiliation(s)
- Arne Jensen
- Department of Obstetrics and Gynecology, Universitätsfrauenklinik Bochum, Knappschaftskrankenhaus, In der Schornau 23-25, 44982 Bochum, Germany.
| | | | | | | |
Collapse
|
144
|
Nolan JP, Morley PT, Vanden Hoek TL, Hickey RW, Kloeck WGJ, Billi J, Böttiger BW, Morley PT, Nolan JP, Okada K, Reyes C, Shuster M, Steen PA, Weil MH, Wenzel V, Hickey RW, Carli P, Vanden Hoek TL, Atkins D. Therapeutic hypothermia after cardiac arrest: an advisory statement by the advanced life support task force of the International Liaison Committee on Resuscitation. Circulation 2003; 108:118-21. [PMID: 12847056 DOI: 10.1161/01.cir.0000079019.02601.90] [Citation(s) in RCA: 507] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- J P Nolan
- Resuscitation Council of Southern Africa
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
145
|
Akisu M, Huseyinov A, Yalaz M, Cetin H, Kultursay N. Selective head cooling with hypothermia suppresses the generation of platelet-activating factor in cerebrospinal fluid of newborn infants with perinatal asphyxia. Prostaglandins Leukot Essent Fatty Acids 2003; 69:45-50. [PMID: 12878450 DOI: 10.1016/s0952-3278(03)00055-3] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Hypoxic-ischemic encephalopathy (HIE) remains one of the most important neurologic complications in the newborn. Several experimental and clinical studies have shown that hypothermia is the most effective means known for protecting the brain against hypoxic-ischemic brain damage. Furthermore, recent data have suggested that platelet-activating factor (PAF) could play a pathophysiologically important role in the progression of hypoxic-ischemic brain injury. The aim of the present study was to investigate the role of head cooling combined with minimal hypothermia in short-term outcome of infants with perinatal asphyxia. In addition, we have examined the effect of head cooling combined with minimal hypothermia on PAF concentrations in cerebrospinal fluid (CSF) after hypoxic-ischemic brain injury. The group of asphyxiated infants (Group 1) consisted of 21 full-term (gestational age >37 weeks). These infants were randomized and divided into either a standard therapy group (Group 1a; n=10) or cooling group (Group 1b; n=11). Head cooling combined with minimal hypothermia (rectal temperature 36.5-36 degrees C) was started as soon as practicable after birth. The infants were cooled for 72h and then were rewarmed at 0.5 degrees C/h. The control group (Group 2) consisted of seven full-term infants and none of these infants showed any sign of asphyxia. To measure PAF concentration in CSF, CSF with lumbar puncture was collected into tubes immediately before the cooling (1-3h after birth) and again after 36h. We had no evidence of severe adverse events related to hypothermia. In Group 1a, two infants died after 72h of life; however, all newborn infants in Group 1b survived. Convulsion required treatment in three infants of standard therapy group (1a); none of the infants in Group 1b had clinical seizure activity. Abnormal EEG patterns were found in four infants of Group 1a; no EEG abnormalities were noted in Group 1b (P<0.05). On admission (before cooling), PAF concentration in CSF of asphyxiated infants was found to be significantly higher when compared with that of control (P<0.001). Mean PAF concentration before initiation of the study was similar in the two asphyxiated groups (Group 1a vs. 1b) (P>0.05). Obtained PAF level in CSF after 36h, showed a profound decline in cooling group of infants compared to Group 1a infants (P<0.01). In conclusion, the present study suggests that cerebral cooling with minimal hypothermia started soon after birth has no severe adverse effects during 72-h cooling period and that short-term outcome of infants are encouraging. Our results also support the hypothesis PAF an important mediator in hypoxic-ischemic brain injury and demonstrate that head cooling combined with minimal hypothermia reduces the normal increase in PAF following hypoxic-ischemic brain injury in full-term infants.
Collapse
Affiliation(s)
- Mete Akisu
- Department of Pediatrics, Ege University Medical School, Bornova, Izmir 35100, Turkey.
| | | | | | | | | |
Collapse
|
146
|
Abstract
BACKGROUND Clinical trials of induced hypothermia have suggested that this treatment may be beneficial in selected patients with neurologic injury. OBJECTIVES To review the topic of induced hypothermia as a treatment of patients with neurologic and other disorders. DESIGN Review article. INTERVENTIONS None. MAIN RESULTS Improved outcome was demonstrated in two prospective, randomized, controlled trials in which induced hypothermia (33 degrees C for 12-24 hrs) was used in patients with anoxic brain injury following resuscitation from prehospital cardiac arrest. In addition, prospective, randomized, controlled trials have been conducted in patients with severe head injury, with variable results. There also have been preliminary clinical studies of induced hypothermia in patients with severe stroke, newborn hypoxic-ischemic encephalopathy, neurologic infection, and hepatic encephalopathy, with promising results. Finally, animal models have suggested that hypothermia that is induced rapidly following traumatic cardiac arrest provides significant neurologic protection and improved survival. CONCLUSIONS Induced hypothermia has a role in selected patients in the intensive care unit. Critical care physicians should be familiar with the physiologic effects, current indications, techniques, and complications of induced hyperthermia.
Collapse
|
147
|
Nolan JP, Morley PT, Hoek TLV, Hickey RW. Therapeutic hypothermia after cardiac arrest. An advisory statement by the Advancement Life support Task Force of the International Liaison committee on Resuscitation. Resuscitation 2003; 57:231-5. [PMID: 12858857 DOI: 10.1016/s0300-9572(03)00184-9] [Citation(s) in RCA: 393] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Jerry P Nolan
- Department of Anaesthesia and Intensive Medicine, Royal United Hospital, UK.
| | | | | | | |
Collapse
|
148
|
Iwata O, Iwata S, Tamura M, Nakamura T, Sugiura M, Ogiso Y. Brain temperature in newborn piglets under selective head cooling with minimal systemic hypothermia. Pediatr Int 2003; 45:163-8. [PMID: 12709142 DOI: 10.1046/j.1442-200x.2003.01682.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Although selective brain hypothermia is expected to be a promising neuroprotective treatment, the thermal distribution under hypothermia is not fully investigated. We applied selective head cooling to seven newborn piglets under general anesthesia in order to investigate the mechanism of cooling. METHODS Seven healthy, large white piglets aged within 5 days after birth were studied. Temperatures were monitored at the superficial brain (0.5 cm), deep brain (2.0 cm), scalp skin, nasopharynx, tympanum, esophagus, and rectum. A radiant heater and a warmer blanket were used to maintain the normal rectal temperature (38.5-39 degrees C). For the first piglet, the coolant temperature was widely changed from 15 degree C to - 20 degree C in order to define the practical range. Subsequently, the coolant temperature was set at 10 degree C, 0 degree C, and - 10 degree C for the remaining six piglets. The target deep brain temperature was set at 35 degree C, as the same reduction of brain temperature might provide moderate brain hypothermia in the human neonate. RESULTS With 0 degree C coolant temperature, the deep brain temperature was cooled to 35 degree C; however, the scalp skin attached to the cooling cap became broadly blotchy and injured in all animals. When we induced minimal systemic hypothermia by 1C for a cohort of three piglets, the deep brain temperature decreased in parallel with the rectal temperature, which enabled us to achieve the target temperature with 10 degrees C coolant without injuring the scalp skin. The scalp skin and nasopharyngeal temperatures were good predictors of both superficial and deep-brain temperatures throughout the experiment. CONCLUSIONS Our results suggest that moderate brain hypothermia may be applied to newborn infants without inducing moderate systemic hypothermia.
Collapse
Affiliation(s)
- Osuke Iwata
- Division of Neonatology, Perinatal Center, Nagano Children's Hospital, Toyoshina, Nagano, Japan.
| | | | | | | | | | | |
Collapse
|
149
|
Cowan F, Rutherford M, Groenendaal F, Eken P, Mercuri E, Bydder GM, Meiners LC, Dubowitz LMS, de Vries LS. Origin and timing of brain lesions in term infants with neonatal encephalopathy. Lancet 2003; 361:736-42. [PMID: 12620738 DOI: 10.1016/s0140-6736(03)12658-x] [Citation(s) in RCA: 386] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
BACKGROUND The role of intrapartum asphyxia in neonatal encephalopathy and seizures in term infants is not clear, and antenatal factors are being implicated in the causal pathway for these disorders. However, there is no evidence that brain damage occurs before birth. We aimed to test the hypothesis that neonatal encephalopathy, early neonatal seizures, or both result from early antenatal insults. METHODS We used brain MRI or post-mortem examination in 351 fullterm infants with neonatal encephalopathy, early seizures, or both to distinguish between lesions acquired antenatally and those that developed in the intrapartum and early post-partum period. We excluded infants with major congenital malformations or obvious chromosomal disorders. Infants were divided into two groups: those with neonatal encephalopathy (with or without seizures), and evidence of perinatal asphyxia (group 1); and those without other evidence of encephalopathy, but who presented with seizures within 3 days of birth (group 2). FINDINGS Brain images showed evidence of an acute insult without established injury or atrophy in 197 (80%) of infants in group 1, MRI showed evidence of established injury in only 2 infants (<1%), although tiny foci of established white matter gliosis, in addition to acute injury, were seen in three of 21 on post-mortem examination. In group 2, acute focal damage was noted in 62 (69%) of infants. Two (3%) also had evidence of antenatal injury. INTERPRETATION Although our results cannot exclude the possibility that antenatal or genetic factors might predispose some infants to perinatal brain injury, our data strongly suggest that events in the immediate perinatal period are most important in neonatal brain injury.
Collapse
Affiliation(s)
- Frances Cowan
- Department of Paediatrics, Faculty of Medicine, Imperial College, Hammersmith Hospital, London, UK.
| | | | | | | | | | | | | | | | | |
Collapse
|
150
|
Johansen FF, Jørgensen HS, Reith J. Prolonged drug-induced hypothermia in experimental stroke. J Stroke Cerebrovasc Dis 2003; 12:97-102. [PMID: 17903912 DOI: 10.1053/jscd.2003.14] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2002] [Indexed: 11/11/2022] Open
Abstract
In experimental and human stroke, hypothermia is strongly related to a favorable outcome. Previous attempts to manipulate the core temperature in focal cerebral ischemia have been based on mechanical cooling. The purpose of the study is to establish a model for long-term drug-induced hypothermia in focal ischemia by pharmacological alteration of the central thermoregulatory set-point. We tested the hypothesis that the dopaminergic agonist Talipexole, which induces hypothermia, reduces infarct size. Body temperature was monitored by a radio-pill-implant. Rats had reversible occlusion of the middle cerebral artery (MCAO) for 30 minutes. Thirty minutes after reflow, the experimental group of rats (n = 10) received an intravenous bolus injection of Talipexole followed by a continuous infusion of Talipexole during the following 24 hours. The control group of rats (n = 10) received a similar treatment regimen with saline only. All rats were killed 7 days after MCAO. Infarct volume was quantified stereologically. The mean body temperature (35.6 + 1.0 degrees C) during 24 hours after bolus injection of Talipexole was significantly lower than in control rats (37.3 +/- 0.5 degrees C), P < .05. Infarct volumes were significantly lower in the Talipexole group (4.7 +/- 1.9 mm3) than in the control group (8.8 +/- 4.7 mm3), P < .04. In the Talipexole treated rats we also observed a significant hypokalemia (P = .001) and a significantly lower index of relative degree of movement (P < .02). Our study shows that the core body temperature was reduced by 1.7 degrees C for 24 hours after MCAO in rats treated with Talipexole. This treatment induced a significant reduction of infarct volume at 7 days after focal ischemia by 47%. We suggest that the reduction in infarct volume is related to drug-induced hypothermia. The hypokalemia in the hypothermic rats is possibly explained by the observed lower degree of movement.
Collapse
|