Effect of increased positive end-expiratory pressure on intracranial pressure and cerebral oxygenation: impact of respiratory mechanics and hypovolemia

BMC Neuroscience

Da-Wei Zhou¹  Jian-Xin Zhou¹  Rong-Guo Yu²  Han Chen²  Xiao-Fen Zhou² 

[1] Department of Critical Care Medicine, Beijing Tiantan Hospital, Capital Medical University, Beijing, China;Fujian Shengli Clinical Medical College, Fujian Medical University, Fuzhou, China;Department of Critical Care Medicine, Fujian Provincial Hospital, Fuzhou, China;

关键词: Positive end-expiratory pressure;    Intracranial pressure;    Cerebral oxygenation;    Cerebral blood flow;    Respiratory mechanics;    Hypovolemia;   

DOI  :  10.1186/s12868-021-00674-9

来源: Springer

【 摘 要 】

BackgroundTo evaluate the impact of positive end-expiratory pressure (PEEP) on intracranial pressure (ICP) in animals with different respiratory mechanics, baseline ICP and volume status.MethodsA total of 50 male adult Bama miniature pigs were involved in four different protocols (n = 20, 12, 12, and 6, respectively). Under the monitoring of ICP, brain tissue oxygen tension and hemodynamical parameters, PEEP was applied in increments of 5 cm H2O from 5 to 25 cm H2O. Measurements were taken in pigs with normal ICP and normovolemia (Series I), or with intracranial hypertension (via inflating intracranial balloon catheter) and normovolemia (Series II), or with intracranial hypertension and hypovolemia (via exsanguination) (Series III). Pigs randomized to the control group received only hydrochloride instillation while the intervention group received additional chest wall strapping. Common carotid arterial blood flow before and after exsanguination at each PEEP level was measured in pigs with intracranial hypertension and chest wall strapping (Series IV).ResultsICP was elevated by increased PEEP in both normal ICP and intracranial hypertension conditions in animals with normal blood volume, while resulted in decreased ICP with PEEP increments in animals with hypovolemia. Increasing PEEP resulted in a decrease in brain tissue oxygen tension in both normovolemic and hypovolemic conditions. The impacts of PEEP on hemodynamical parameters, ICP and brain tissue oxygen tension became more evident with increased chest wall elastance. Compare to normovolemic condition, common carotid arterial blood flow was further lowered when PEEP was raised in the condition of hypovolemia.ConclusionsThe impacts of PEEP on ICP and cerebral oxygenation are determined by both volume status and respiratory mechanics. Potential conditions that may increase chest wall elastance should also be ruled out to avoid the deleterious effects of PEEP.

【 授权许可】

CC BY