1
|
Memisoglu A, Hinton M, Elsayed Y, Graham R, Dakshinamurti S. Assessment of Autoregulation of the Cerebral Circulation during Acute Lung Injury in a Neonatal Porcine Model. CHILDREN (BASEL, SWITZERLAND) 2024; 11:611. [PMID: 38790606 PMCID: PMC11119854 DOI: 10.3390/children11050611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Revised: 04/30/2024] [Accepted: 05/15/2024] [Indexed: 05/26/2024]
Abstract
In neonates with acute lung injury (ALI), targeting lower oxygenation saturations is suggested to limit oxygen toxicity while maintaining vital organ function. Although thresholds for cerebral autoregulation are studied for the management of premature infants, the impact of hypoxia on hemodynamics, tissue oxygen consumption and extraction is not well understood in term infants with ALI. We examined hemodynamics, cerebral autoregulation and fractional oxygen extraction, as measured by near-infrared spectroscopy (NIRS) and blood gases, in a neonatal porcine oleic acid injury model of moderate ALI. We hypothesized that in ALI animals, cerebral oxygen extraction would be increased to a greater degree than kidney or gut oxygen extraction as indicative of the brain's adaptive efforts to increase cerebral oxygen extraction at the expense of splanchnic end organs. Fifteen anesthetized, ventilated 5-day-old neonatal piglets were divided into moderate lung injury by treatment with oleic acid or control (sham injection). The degree of lung injury was quantified at baseline and after establishment of ALI by blood gases, ventilation parameters and calculated oxygenation deficit, hemodynamic indices by echocardiography and lung injury score by ultrasound. PaCO2 was maintained constant during ventilation. Cerebral, renal and gut oxygenation was determined by NIRS during stepwise decreases in inspired oxygen from 50% to 21%, correlated with PaO2 and PvO2; changes in fractional oxygen extraction (ΔFOE) were calculated from NIRS and from regional blood gas samples. The proportion of cerebral autoregulation impairment attributable to blood pressure, and to hypoxemia, was calculated from autoregulation nomograms. ALI manifested as hypoxemia with increasing intrapulmonary shunt fraction, decreased lung compliance and increased resistance, and marked increase in lung ultrasound score. Brain, gut and renal NIRS, obtained from probes placed over the anterior skull, central abdomen and flank, respectively, correlated with concurrent SVC (brain) or IVC (gut, renal) PvO2 and SvO2. Cerebral autoregulation was impaired after ALI as a function of blood pressure at all FiO2 steps, but predominantly by hypoxemia at FiO2 < 40%. Cerebral ΔFOE was higher in ALI animals at all FiO2 steps. We conclude that in an animal model of neonatal ALI, cerebrovascular blood flow regulation is primarily dependent on oxygenation. There is not a defined oxygenation threshold below which cerebral autoregulation is impaired in ALI. Cerebral oxygen extraction is enhanced in ALI, reflecting compensation for exhausted cerebral autoregulation due to the degree of hypoxemia and/or hypotension, thereby protecting against tissue hypoxia.
Collapse
Affiliation(s)
- Asli Memisoglu
- Biology of Breathing Theme, Children’s Hospital Research Institute of Manitoba, Winnipeg, MB R3E 3P4, Canada; (A.M.); (M.H.)
| | - Martha Hinton
- Biology of Breathing Theme, Children’s Hospital Research Institute of Manitoba, Winnipeg, MB R3E 3P4, Canada; (A.M.); (M.H.)
- Department of Physiology, University of Manitoba, 745 Bannatyne Ave., Winnipeg, MB R3E 0J9, Canada
| | - Yasser Elsayed
- Section of Neonatology, Department of Pediatrics, Women’s Hospital, Health Sciences Centre, 665 William Ave., Winnipeg, MB R3E 0L8, Canada;
| | - Ruth Graham
- Departments of Anesthesiology, Perioperative and Pain Medicine, Health Sciences Centre, 671 William Ave., Winnipeg, MB R3E 0Z3, Canada;
| | - Shyamala Dakshinamurti
- Biology of Breathing Theme, Children’s Hospital Research Institute of Manitoba, Winnipeg, MB R3E 3P4, Canada; (A.M.); (M.H.)
- Department of Physiology, University of Manitoba, 745 Bannatyne Ave., Winnipeg, MB R3E 0J9, Canada
- Section of Neonatology, Department of Pediatrics, Women’s Hospital, Health Sciences Centre, 665 William Ave., Winnipeg, MB R3E 0L8, Canada;
| |
Collapse
|
2
|
Ringer SK, Schmid A, Weiss M, Ohlerth S, Spielmann N, Clausen NG. Non-surgical external jugular vein catheterization using an ear vein access in piglets. Lab Anim 2023; 57:642-649. [PMID: 37077144 DOI: 10.1177/00236772231167224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/21/2023]
Abstract
The objective of this study was to investigate the feasibility of external jugular vein catheterization through an ear vein in piglets. Forty-six sevoflurane-midazolam anaesthetized piglets were included. External jugular vein catheterization was conducted through the ear vein using the Seldinger technique. Part 1 (n = 27): optimal puncture site was based on the deltoid tuberosity as a landmark to reach the external jugular vein. The final position of the catheter was verified in 25 piglets using computer tomography. Catheterization time was recorded and patency of the catheter assessed by repeated blood sampling for up to 4 h. Part 2 (n = 19): ear vein catheterization was without taking into account any landmarks. Functionality for blood sampling was evaluated as described in part 1. Catheter advancement was possible in 25/27 and 18/19 piglets in parts 1 and 2, respectively. Median (range) time required for successful catheterization was 1.95 (1-10) min (n = 38). The deltoid tuberosity was a good landmark to reach the external jugular vein. But blood sampling was also possible through catheters ending slightly cranial to the external jugular vein. Despite successful catheter advancement, blood sampling was not possible from one catheter in each part of the study (total: two piglets). One of these catheters presented luminal damage, while the other one presented as normal after being removed from the animal. Summarizing, central vein catheterization through the ear vein was feasible in 93.5% and repeated blood sampling was possible in 89.1% of the piglets (n = 46).
Collapse
Affiliation(s)
- S K Ringer
- Section Anaesthesiology, Department of Clinical Diagnostics and Services, Vetsuisse Faculty University of Zurich, Switzerland
| | - A Schmid
- Section Anaesthesiology, Department of Clinical Diagnostics and Services, Vetsuisse Faculty University of Zurich, Switzerland
| | - M Weiss
- Department of Anaesthesia, University Children's Hospital Zurich, Switzerland
- Children's Research Centre, University Children's Hospital of Zurich, University of Zurich, Switzerland
| | - S Ohlerth
- Clinic of Diagnostic Imaging, Department of Clinical Diagnostics and Services, Vetsuisse Faculty University of Zurich, Switzerland
| | - N Spielmann
- Department of Anaesthesia, University Children's Hospital Zurich, Switzerland
- Children's Research Centre, University Children's Hospital of Zurich, University of Zurich, Switzerland
| | - N G Clausen
- Department of Anaesthesia, University Children's Hospital Zurich, Switzerland
- Children's Research Centre, University Children's Hospital of Zurich, University of Zurich, Switzerland
- Department of Anaesthesiology and Intensive Care, Odense University Hospital, Denmark
| |
Collapse
|
3
|
Fujimoto T, Dobashi K, Fujii N, Matsutake R, Nishiyasu T. Hypocapnia attenuates local skin thermal perception to innocuous warm and cool stimuli in normothermic resting humans. Am J Physiol Regul Integr Comp Physiol 2023; 324:R120-R127. [PMID: 36534588 DOI: 10.1152/ajpregu.00126.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
When one is exposed to a stressful situation in their daily life, a common response is hyperventilation. Although the physiological significance of stress-induced hyperventilation remains uncertain, this response may blunt perception of the stress-inducing stimulus. This study examined the effects of voluntary hyperventilation and resultant hypocapnia on the local skin thermal detection threshold in normothermic resting humans. Local skin thermal detection thresholds were measured in 15 young adults (three females) under three breathing conditions: 1) spontaneous breathing (Control trial), 2) voluntary hypocapnic hyperventilation (HH trial), and 3) voluntary normocapnic hyperventilation (NH trial). Local skin thermal detection thresholds were measured using thermostimulators containing a Peltier element that were attached to the forearm and forehead. The temperature of the probe was initially equilibrated to the skin temperature, then gradually increased or decreased at a constant rate (±0.1 °C/s) until the participants felt warmth or coolness. The difference between the initial skin temperature and the local skin temperature at which the participant noticed warmth/coolness was assessed as an index of the local skin warm/cool detection threshold. Local detection of warm and cool stimuli did not differ between the Control and NH trials, but it was blunted in the HH trial as compared with the Control and NH trials, except for detection of warm stimuli on the forearm. These findings suggest that hyperventilation-induced hypocapnia, not hyperventilation per se, attenuates local skin thermal perception, though changes in responses to warm stimuli may not be clearly perceived at some skin areas (e.g., forearm).
Collapse
Affiliation(s)
- Tomomi Fujimoto
- Department of Health and Sports, Niigata University of Health and Welfare, Niigata, Japan.,Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata, Japan
| | - Kohei Dobashi
- Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan.,Faculty of Education, Hokkaido University of Education, Asahikawa, Japan
| | - Naoto Fujii
- Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan.,Advanced Research Initiative for Human High Performance (ARIHHP), University of Tsukuba, Tsukuba, Japan
| | - Ryoko Matsutake
- Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
| | - Takeshi Nishiyasu
- Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan.,Advanced Research Initiative for Human High Performance (ARIHHP), University of Tsukuba, Tsukuba, Japan
| |
Collapse
|
4
|
Duan Z, Song P, Yang C, Deng L, Jiang Y, Deng F, Jiang X, Chen Y, Yang G, Ma Y, Deng W. The impact of hyperglycaemic crisis episodes on long-term outcomes for inpatients presenting with acute organ injury: A prospective, multicentre follow-up study. Front Endocrinol (Lausanne) 2022; 13:1057089. [PMID: 36545333 PMCID: PMC9760800 DOI: 10.3389/fendo.2022.1057089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 11/16/2022] [Indexed: 12/07/2022] Open
Abstract
BACKGROUND The long-term clinical outcome of poor prognosis in patients with diabetic hyperglycaemic crisis episodes (HCE) remains unknown, which may be related to acute organ injury (AOI) and its continuous damage after hospital discharge. This study aimed to observe the clinical differences and relevant risk factors in HCE with or without AOI. METHODS A total of 339 inpatients were divided into an AOI group (n=69) and a non-AOI group (n=270), and their differences and risk factors were explored. The differences in clinical outcomes and prediction models for evaluating the long-term adverse events after hospital discharge were established. RESULTS The mortality among cases complicated by AOI was significantly higher than that among patients without AOI [8 (11.59%) vs. 11 (4.07%), Q = 0.034] during hospitalization. After a 2-year follow-up, the mortality was also significantly higher in patients with concomitant AOI than in patients without AOI after hospital discharge during follow-up [13 (21.31%) vs. 15 (5.8%), Q < 0.001]. The long-term adverse events in patients with concomitant AOI were significantly higher than those in patients without AOI during follow-up [15 (24.59%) vs. 31 (11.97%), Q = 0.015]. Furthermore, Blood β-hydroxybutyric acid (P = 0.003), Cystatin C (P <0.001), serum potassium levels (P = 0.001) were significantly associated with long-term adverse events after hospital discharge. CONCLUSIONS The long-term prognosis of HCE patients complicated with AOI was significantly worse than that of HCE patients without AOI. The laboratory indicators were closely correlated with AOI, and future studies should explore the improvement of clinical outcome in response to timely interventions.
Collapse
Affiliation(s)
- Zixiao Duan
- Department of Endocrinology, Chongqing Emergency Medical Center, Chongqing University Central Hospital, Chongqing, China
- Department of Endocrinology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Peiyang Song
- Department of Endocrinology, Chongqing Emergency Medical Center, Chongqing University Central Hospital, Chongqing, China
| | - Cheng Yang
- Department of Endocrinology, Chongqing Emergency Medical Center, Chongqing University Central Hospital, Chongqing, China
| | - Liling Deng
- Department of Endocrinology, Chongqing Emergency Medical Center, Chongqing University Central Hospital, Chongqing, China
| | - Youzhao Jiang
- Department of Endocrinology, Banan People’s Hospital of Chongqing, Chongqing, China
| | - Fang Deng
- Department of Endocrinology, Chongqing Southwest Hospital, Chongqing, China
| | - Xiaoyan Jiang
- Department of Endocrinology, Chongqing Emergency Medical Center, Chongqing University Central Hospital, Chongqing, China
| | - Yan Chen
- Department of Endocrinology, Chongqing Emergency Medical Center, Chongqing University Central Hospital, Chongqing, China
| | - Gangyi Yang
- Department of Endocrinology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Yu Ma
- Department of Endocrinology, Chongqing Emergency Medical Center, Chongqing University Central Hospital, Chongqing, China
| | - Wuquan Deng
- Department of Endocrinology, Chongqing Emergency Medical Center, Chongqing University Central Hospital, Chongqing, China
- *Correspondence: Wuquan Deng,
| |
Collapse
|
5
|
Schmid SM, Steinhoff-Wagner J. Behavior and body temperature alterations in piglets anesthetized for castration during a four-hour recovery phase. Appl Anim Behav Sci 2021. [DOI: 10.1016/j.applanim.2021.105497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
6
|
Effect of Permissive Mild Hypercapnia on Cerebral Vasoreactivity in Infants: A Randomized Controlled Crossover Trial. Anesth Analg 2021; 133:976-983. [PMID: 33410612 DOI: 10.1213/ane.0000000000005325] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Mechanical ventilation interferes with cerebral perfusion via changes in intrathoracic pressure and/or as a consequence of alterations in CO2. Cerebral vascular vasoreactivity is dependent on CO2, and hypocapnia can potentially lead to vasoconstriction and subsequent decrease in cerebral blood flow. Thus, we aimed at characterizing whether protective ventilation with mild permissive hypercapnia improves cerebral perfusion in infants. METHODS Following ethical approval and parental consent, 19 infants were included in this crossover study and randomly assigned to 2 groups for which the initial ventilation parameters were set to achieve an end-tidal carbon dioxide (Etco2) of 6.5 kPa (group H: mild hypercapnia, n = 8) or 5.5 kPa (group N: normocapnia, n = 11). The threshold was then reversed before going back to the initial set value of normo- or hypercapnia. At each step, hemodynamic, respiratory, and near-infrared spectroscopy (NIRS)-derived parameters, including tissue oxygenation index (TOI) and tissue hemoglobin index (THI), concentration of deoxygenated hemoglobin (HHb) and oxygenated hemoglobin (O2Hb), were collected. Concomitantly, sevoflurane maintenance concentration, ventilatory (driving pressure) and hemodynamic parameters, as mean arterial pressure (MAP), were recorded. RESULTS Targeting an Etco2 of 5.5 kPa resulted in significantly higher mean driving pressure than an Etco2 of 6.5 kPa (P < .01) with no difference between the groups in end-tidal sevoflurane, MAP, and heart rate. A large scatter was observed in NIRS-derived parameters, with no evidence for difference in Etco2 changes between or within groups. A mild decrease with time was observed in THI and MAP in infants randomly assigned to group N (P < .036 and P < .017, respectively). When pooling all groups together, a significant correlation was found between the changes in MAP and TOI (r = 0.481, P < .001). CONCLUSIONS Allowing permissive mild hypercapnia during mechanical ventilation of infants led to lower driving pressure and comparable hemodynamic, respiratory, and cerebral oxygenation parameters than during normocapnia. Whereas a large scatter in NIRS-derived parameters was observed at all levels of Etco2, the correlation between TOI and MAP suggests that arterial pressure is an important component of cerebral oxygenation at mild hypercapnia.
Collapse
|
7
|
[Near-infrared spectroscopy : Technique, development, current use and perspectives]. Anaesthesist 2020; 70:190-203. [PMID: 32930804 DOI: 10.1007/s00101-020-00837-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Near-infrared spectroscopy (NIRS) has been available in research and clinical practice for more than four decades. Recently, there have been numerous publications and substantial developments in the field. This article describes the clinical application of NIRS in relation to current guidelines, with a focus on pediatric and cardiac anesthesia. It discusses technical and physiological principles, pitfalls in clinical use and presents (patho)physiological influencing factors and derived variables, such as fractional oxygen extraction (FOE) and the cerebral oxygen index (COx). Recommendations for the interpretation of NIRS values in connection with influencing factors, such as oxygen transport capacity, gas exchange and circulation as well as an algorithm for cardiac anesthesia are presented. Limitations of the method and the lack of comparability of values from different devices as well as generally accepted standard values are explained. Technical differences and advantages compared to pulse oxymetry and transcranial Doppler sonography are illuminated. Finally, the prognostic significance and requirements for future clinical studies are discussed.
Collapse
|
8
|
Ringer SK, Clausen NG, Spielmann N, Weiss M. Effects of hypothermia and hypothermia combined with hypocapnia on cerebral tissue oxygenation in piglets. Paediatr Anaesth 2020; 30:970-976. [PMID: 32506675 DOI: 10.1111/pan.13943] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 05/26/2020] [Accepted: 05/27/2020] [Indexed: 12/20/2022]
Abstract
BACKGROUND Hypothermia and its combination with hypocapnia are frequently associated with anesthesia. AIMS The goal was to investigate the effects of hypothermia and hypothermia combined with hypocapnia (hypothermia-hypocapnia) on cerebral tissue oxygenation in anesthetized piglets. METHODS Twenty anesthetized piglets were randomly allocated to hypothermia (n = 10) or hypothermia-hypocapnia (n = 10). Cerebral monitoring comprised a tissue oxygen partial pressure (PtO2 ), a laser Doppler probe, and a near-infrared spectroscopy sensor, measuring regional oxygen saturation (rSO2 ). After baseline recordings, hypothermia (35.5-36.0°C) with or without hypocapnia (target PaCO2 : 28-30 mm Hg) was induced. Once treatment goals were achieved (Tr0), they were maintained for 30 minutes (Tr30). RESULTS No changes in PtO2 but a significant increase in rSO2 (Tr0 (mean difference 8.9[95% CI for difference3.99 to 13.81], P < .001); Tr30 (10.8[6.20 to 15.40], P < .001)) were detected during hypothermia. With hypothermia-hypocapnia, a decrease in PtO2 (Tr0 (-3.2[-6.01 to -0.39], P = .021; Tr30 (-3.3[-5.8 to -0.80], P = .006)) and no significant changes in rSO2 occurred. Cerebral blood flow decreased significantly from baseline to Tr0 independently of treatment (-0.89[-0.18 to -0.002], P = .042), but this was more consistently observed with hypothermia-hypocapnia. CONCLUSIONS The hypothermia-induced reduction in oxygen delivery was compensated by lowered metabolic demand. However, hypothermia was not able to compensate for an additional reduction in oxygen delivery caused by simultaneous hypocapnia. This resulted in a PtO2 drop, which was not reflected by a downshift in rSO2 .
Collapse
Affiliation(s)
- Simone K Ringer
- Department of Clinical Diagnostics and Services, Section Anaesthesiology, Vetsuisse Faculty University of Zurich, Zurich, Switzerland
| | - Nicola G Clausen
- Department of Anaesthesiology, University Children's Hospital Zurich, Zurich, Switzerland.,Children's Research Centre, University Children's Hospital of Zurich, University of Zurich, Zurich, Switzerland.,Department of Anaesthesiology and Intensive Care, Odense University Hospital, Odense, Denmark
| | - Nelly Spielmann
- Department of Anaesthesiology, University Children's Hospital Zurich, Zurich, Switzerland.,Children's Research Centre, University Children's Hospital of Zurich, University of Zurich, Zurich, Switzerland
| | - Markus Weiss
- Department of Anaesthesiology, University Children's Hospital Zurich, Zurich, Switzerland.,Children's Research Centre, University Children's Hospital of Zurich, University of Zurich, Zurich, Switzerland
| |
Collapse
|
9
|
Brain interstitial pH changes in the subacute phase of hypoxic-ischemic encephalopathy in newborn pigs. PLoS One 2020; 15:e0233851. [PMID: 32470084 PMCID: PMC7259698 DOI: 10.1371/journal.pone.0233851] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 05/13/2020] [Indexed: 01/24/2023] Open
Abstract
Brain interstitial pH (pHbrain) alterations play an important role in the mechanisms of neuronal injury in neonatal hypoxic-ischemic encephalopathy (HIE) induced by perinatal asphyxia. The newborn pig is an established large animal model to study HIE, however, only limited information on pHbrain alterations is available in this species and it is restricted to experimental perinatal asphyxia (PA) and the immediate reventilation. Therefore, we sought to determine pHbrain over the first 24h of HIE development in piglets. Anaesthetized, ventilated newborn pigs (n = 16) were instrumented to control major physiological parameters. pHbrain was determined in the parietal cortex using a pH-selective microelectrode. PA was induced by ventilation with a gas mixture containing 6%O2-20%CO2 for 20 min, followed by reventilation with air for 24h, then the brains were processed for histopathology assessment. The core temperature was maintained unchanged during PA (38.4±0.1 vs 38.3±0.1°C, at baseline versus the end of PA, respectively; mean±SEM). In the arterial blood, PA resulted in severe hypoxia (PaO2: 65±4 vs 23±1*mmHg, *p<0.05) as well as acidosis (pHa: 7.53±0.03 vs 6.79±0.02*) that is consistent with the observed hypercapnia (PaCO2: 37±3 vs 160±6*mmHg) and lactacidemia (1.6±0.3 vs 10.3±0.7*mmol/L). Meanwhile, pHbrain decreased progressively from 7.21±0.03 to 5.94±0.11*. Reventilation restored pHa, blood gases and metabolites within 4 hours except for PaCO2 that remained slightly elevated. pHbrain returned to 7.0 in 29.4±5.5 min and then recovered to its baseline level without showing secondary alterations during the 24 h observation period. Neuropathological assessment also confirmed neuronal injury. In conclusion, in spite of the severe acidosis and alterations in blood gases during experimental PA, pHbrain recovered rapidly and notably, there was no post-asphyxia hypocapnia that is commonly observed in many HIE babies. Thus, the neuronal injury in our piglet model is not associated with abnormal pHbrain or low PaCO2 over the first 24 h after PA.
Collapse
|