Cerebral perfusion pressure and cerebral tissue oxygen tension in a patient during cardiopulmonary resuscitation
Objective: To report on the effects of cardiopulmonary resuscitation (CPR) instituted immediately after a cardiac arrest on cerebral perfusion pressure (CPP) and cerebral tissue oxygen tension (PbrO2).
Design: Case report.
Setting: ICU of a university hospital.
Patient: A head-injured 17-year-old man submitted to multimodal neurological monitoring underwent sudden cardiac arrest and successful CPR.
Interventions: External chest compression, 100% oxygen ventilation, volume expansion and standard ACLS protocols.
Measurements and results: Heart rate, ECG, mean arterial blood pressure (MABP), ETCO2,PaO2, intracranial pressure (ICP), CPP and PbrO2 were continuously monitored during CPR and data recorded at 15-s intervals by a dedicated personal computer. At the onset of the cardiac arrest, PbrO2 decreased to zero. The institution of CPR resulted in a progressive increase of MABP, CPP and PbrO2. Assuming, on the basis of previous experimental and clinical reports, 8 mmHg PbrO2 as a possible ischaemic/hypoxic threshold value, during the first 6.5 min of CPR, PbrO2 values were below this threshold (range 0–7 mmHg) and CPP values were <25 mmHg for 81.5% of the time. In the following 5.5 min, more efficient CPR generated CPP values >25 mmHg for 77.3% of the time. These values were associated with a PbrO2 >8 mmHg (range 8–28 mmHg) at all times.
Conclusions: In the clinical setting of a witnessed cardiac arrest, immediate institution of CPR can be effective in generating PbrO2 values above a supposed ischaemic/hypoxic threshold when CPP is >25 mmHg. PbrO2 monitoring by the Licox system is sensitive and reliable, even at low values, and can be suitable for evaluating cerebral oxygenation during experimental CPR.
KeywordsCardiac arrest Cardiopulmonary resuscitation Brain tissue partial pressure of oxygen Intracranial pressure Cerebral perfusion pressure Cerebral oxygen metabolism
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