Regional cerebral saturation monitoring during withdrawal of life support until death.

Abstract

The aim of this pilot study was to explore the regional cerebral oxygen saturation (rSO₂) during the process of dying in Intensive Care Unit (ICU) patients in whom it was decided to withdraw life support. Regional cerebral saturation was measured from the moment active treatment was stopped until the moment of death, defined as the onset of asystole. Simultaneously, heart rate and arterial blood pressure were recorded using a radial arterial catheter. Baseline rSO₂ values were calculated as mean values over one hour in stable haemodynamic conditions immediately after the decision to withdraw life support. Cerebral saturation was measured in six dying ICU patients. The mean age of patients was 64year. The median baseline rSO₂ value was 64% (58%-68%). At time of death, median rSO₂ was 33% (7%-40%). The median decrease in rSO₂ from baseline until death was 31% (25%-45%). The median decrease in rSO₂ observed during the last hour before time of death was 20% (12%-31%). A continuous and patient specific decrease in rSO₂ was observed in all patients with a simultaneous decrease in MAP. However, the absolute rSO₂ value at moment death was clinically determined, had a broad range, indicating that there is no clear cut-off rSO₂ value for death probably due to the heterogeneity of the studied population. Taken together, these observations highlight the importance of following trends and comparing rSO₂ values in the cardiac arrest setting.