Hypothermia-associated Protection from Ischemic Brain Injury

Ct, Wass; Wl, Lanier

doi:10.1097/00004311-199603440-00008

Cited by 44 publications

(19 citation statements)

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“…The authors conclude that, irrespective of a change in coupling of blood flow and metabolism during deep cerebral hypothermia, cerebral metabolism is a main determinant of CBF during SBH. Key Words: Selective brain hypothermia-Cerebral flowmetabolism coupling-Microspheres-Pig.There is considerable evidence that hypothermia is a useful intrainsult and postinsult treatment modality for brain injury caused by hypoxia-ischemia, trauma, or neonatal asphyxia (Dietrich, 1992, Gunn et al, 1998bWass et al, 1996). Moreover, systemic hypothermia is routinely used during cardiopulmonary bypass in cardiovascular surgery (McCullough et al, 1999;Jonas, 1998).…”

mentioning

confidence: 99%

Coupling of Cerebral Blood Flow and Oxygen Metabolism in Infant Pigs during Selective Brain Hypothermia

Walter

Bauer

Kuhnen

et al. 2000

J Cereb Blood Flow Metab

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Summary:Studies documenting the cerebral hemodynamic consequences of selective brain hypothermia (SBH) have yielded conflicting data. Therefore, the authors have studied the effect of SBH on the relation of cerebral blood flow (CBF) and CMRO 2 in the forebrain of pigs. Selective brain hypothermia was induced in seven juvenile pigs by bicarotid perfusion of the head with extracorporally cooled blood. Cooling and stepwise rewarming of the brain to a T brain of 38°C, 25°C, 30°C, and 38°C at normothermic T trunk (38°C) decreased CBF from 71 ± 12 mL 100 g −1 min −1 at normothermia to 26 ± 3 mL 100 g −1 min −1 and 40 ± 12 mL 100 g −1 min −1 at a T brain of 25°C and 30°C, respectively. The decrease of CMRO 2 during cooling of the brain to a T brain of 25°C resulted in a mean Q 10 of 2.8. The ratio between CBF and CMRO 2 was increased at a T brain of 25°C indicating a change in coupling of flow and metabolism. Despite this change, regional perfusion remained coupled to regional temperatures during deep cerebral hypothermia. The data demonstrate that SBH decreases CBF and oxygen metabolism to a degree comparable with the cerebrovascular and metabolic effects of systemic hypothermia. The authors conclude that, irrespective of a change in coupling of blood flow and metabolism during deep cerebral hypothermia, cerebral metabolism is a main determinant of CBF during SBH. Key Words: Selective brain hypothermia-Cerebral flowmetabolism coupling-Microspheres-Pig.There is considerable evidence that hypothermia is a useful intrainsult and postinsult treatment modality for brain injury caused by hypoxia-ischemia, trauma, or neonatal asphyxia (Dietrich, 1992, Gunn et al., 1998bWass et al., 1996). Moreover, systemic hypothermia is routinely used during cardiopulmonary bypass in cardiovascular surgery (McCullough et al., 1999;Jonas, 1998). Because systemic hypothermia causes potentially hazardous side effects (for review see Schubert, 1995), selective brain hypothermia (SBH) is being looked at more intensively with respect to feasibility and cerebroprotective effects (Gunn et al., 1997;Kuluz et al., 1992;Schwartz et al., 1996b).Hypothermic cerebral protection is mediated in part by a reduction of cerebral metabolism (Lanier, 1995). Numerous animal and human studies have shown that systemic hypothermia decreases cerebral blood flow (CBF) and CMRO 2 (Greeley et al., 1993;Michenfelder et al., 1991). However, very few studies have addressed the cerebrovascular and cerebral metabolic responses to SBH. Currently there is no study documenting the physiologic effects of SBH on CMRO 2 and, consequently, on the coupling of CBF and CMRO 2 . Furthermore, investigations documenting the hemodynamic consequences of SBH have reported seemingly conflicting data on the cerebrovascular effects of SBH. A single study in rats has shown that external head cooling results in an increase of CBF (Kuluz et al., 1993). Based on this study it has been concluded that the method of cooling (systemic vs. selective) may be a key factor in determining the cerebral he...

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mentioning

confidence: 99%

Coupling of Cerebral Blood Flow and Oxygen Metabolism in Infant Pigs during Selective Brain Hypothermia

Walter

Bauer

Kuhnen

et al. 2000

J Cereb Blood Flow Metab

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“…Temperatures can be easily reduced to 34°C, which has been found to decrease cerebral metabolism by 10 or 15% from normothermic levels. 38 It has also been demonstrated in animal studies that significant reductions in excitatory amino acid release have occurred after forebrain ischemia with moderate hypothermia. 3 Transmembrane ion flux is also reduced and basal energy expenditure is diminished providing a neuron-sparing effect.…”

Section: Neurosurg Focus / Volume 12 / May 2002mentioning

confidence: 99%

Perioperative management of complex skull base surgery: the anesthesiologist's point of view

Jellish¹,

Murdoch²,

Jp³

2002

FOC

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The anesthetic management of complex skull base surgical procedures provides unique problems and concerns for the neuroanesthesiologist. Positioning to access the skull base could put the patient at risk for peripheral nerve injury and some of the positions may increase the risk for air emboli. In addition, tumor pathology and involvement with vital structures could increase the chances for substantive blood loss, destruction of associated nerves or vessels, and may require temporary occlusion of the carotid artery necessitating intraoperative neuroprotection. Neurophysiological monitors may also be used to safeguard nerve function and anesthetic techniques must be adjusted to accommodate their use. Finally, postoperative morbidity may be affected by surgical approach to the skull base and the anesthesiologist should be aware of which approach may produce a greater incidence of pain, nausea, and vomiting in the postoperative period. The authors discuss the anesthetic concerns and management for complex cranial base surgery. Different approaches will be discussed and comparisons of perioperative parameters between these approaches will be made with data provided by retrospective chart review of more than 600 skull base procedures performed at the authors' institution over the last 10 years. This information should help guide decision making concerning anesthetic management for these skull base procedures.

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“…6~7 This technique is sometimes used to facilitate surgical repair of complex cardiac or cerebrovascular anomalies. 27 Efforts to reduce temperature therapeutically to < 30~ outside the setting of cardiopulmonary bypass-assisted circulation have met with dismal results. This is because the temperature reductions produce aberrations of systemic physiology that are detrimental to the patient, regardless of whether there is a cerebral ischemic insult or not.…”

Section: Steroidsmentioning

confidence: 99%

“…This is because the temperature reductions produce aberrations of systemic physiology that are detrimental to the patient, regardless of whether there is a cerebral ischemic insult or not. 6, 27 It has long been assumed that any temperature-mediated cerebral protection is the result of a reduction in cerebral metabolic rate. 17 Perhaps allegiance to this assumption, combined with the above-mentioned experience with hypothermia outside cardiopulmonary bypass, delayed investigation into the effect of mild reductions in temperature (i.e., temperature reductions above 30~ on post-ischemic outcome.…”

Section: Steroidsmentioning

confidence: 99%

“…6,27 De plus, une 16g~re hypothermie peut amtliorer l'tvolution quand eile est amorc& soit avant ou 16g&ement apr~s l'accident ischtmique. 27 Depuis 1987, de nombreuses &udes avec des modules animaux ont dtmontr~ de mani~re coh~rente que les rtductions de temptrature de 6 ~ prot~gent le cerveau de 16sions ischtmiques. 6,27 Au contraire, les augmentations de temptrature nuisent h l'~volu-tion.…”

Section: Le Contr61e De La Tempandamreunclassified

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