Per- and postoperative changes in the arterio-venous oxygen content difference (AVDO2) in patients subjected to craniotomy for cerebral tumours

Abstract

Sixteen patients with supratentorial cerebral tumours were subjected to craniotomy under thiopentone, fentanyl, nitrous oxide, halothane anaesthesia during moderate hypocapnia (PaCO2 level 4.0 kPa). The arterio-venous oxygen content difference (AVDO2) was measured peroperatively, and repeatedly during the first three hours after extubation. Peroperatively the level of AVDO2 averaged 8.0 vol% during opening of the dura, and decreased to 7.0 vol% during closure of the dura (P less than 0.05). Immediately after extubation the AVDO2 decreased to 4.3 vol% (P less than 0.05), and during the next 3 hours a gradual increase to 5.8 vol% (P less than 0.05) was disclosed. In individual cases the postoperative changes in AVDO2 correlated fairly well with changes in mean arterial blood pressure (MABP), but other factors including duration of the operation, age of the patients, size of the tumour, level of PaCO2 and adaptation to prolonged hyperventilation during operation are supposed to be responsible for the low levels of AVDO2 observed in the postoperative period.

Cerebral hyperaemia after isoflurane anaesthesia for craniotomy of patients with supratentorial brain tumour

“…Without CBF monitoring in their study, they can only assume this phenomenon is a consequence of an increase of global CBF. They also find that AVDO 2 correlated fairly well with changes in MAP, but conclude that the reason for changes in AVDO 2 seems to be multifactorial . In a clinical study on CBF regulation in patients with intracranial lesions, Stuer C et al .…”

“…Several studies have described the occurrence of cerebral hyperaemia after craniotomy . Post‐operative cerebral hyperperfusion increases the risk of disastrous complications, such as intracranial hypertension, cerebral oedema, and intracerebral haemorrhage .…”