Cerebral oxygen saturation and cerebral blood flow are relatively stable during single-lung ventilation, if normocapnia is maintained

Introduction

Previously a report has suggested that administration of a lung-protective strategy for one-lung ventilation (OLV) results in oxygen desaturation of the brain parenchyma. The aim of the present work was to test whether the maintenance of normocapnia during a protective OLV strategy results in alteration of cerebral blood flow and cerebral oxygen saturation.

Methods

Data were obtained from 15 patients undergoing thoracic surgery and necessitating OLV of more than 1 hour. Cerebral oxygen saturation (Satcereb) was continuously monitored by the INVOS 5100C Cerebral Oxymeter System along with measurement of cerebral blood flow velocity (MCAV) by transcranial Doppler sonography. Arterial blood samples were taken for blood gas analysis in the awake state, in the supine position after induction during DLV, in the lateral decubitus position during DLV and every 15 minutes during OLV.

Results

Satcereb increased significantly when DLV was started with FiO₂ 1.0 and remained stable during the course of the study. When ventilation was changed from DLV to OLV, no significant change was observed. A significant decrease of cerebral oxygen saturation was found compared with the value observed during DLV in the lateral decubitus at the time point of 60 minutes after the start of OLV. No significant changes in the MCAV were observed throughout the course of the thoracic surgical procedure.

Conclusions

OLV does not result in clinically relevant decreases in cerebral blood flow and cerebral oxygen saturation during application of lung-protective ventilation if normocapnia is maintained.