Arginine vasopressin reduces cerebral oxygenation and cerebral blood volume during intact circulation in swine a near infrared spectroscopy study

Background and objective: The aim of the present study was to investigate the impact of arginine vasopressin (AVP), a drug currently under investigation for use during cardiopulmonary resuscitation, on cerebral oxygenation and cerebral blood volume (CBV) in pigs with intact systemic circulation using near infrared spectroscopy. Methods: Nine healthy pigs were anaesthetized and subjected to invasive haemodynamic monitoring as well as to non-invasive determination (with near infrared spectroscopy) of changes in the Tissue Oxygenation Index (TOI is the ratio of oxygenated to total tissue haemoglobin), Tissue Haemoglobin Index (THI, representing CBV) and cytochrome oxidase (Delta CytOx, representing the balance of intracellular oxygen supply). Results: At both 3 and 5 min after AVP administration, TOI, THI and Delta CytOx were significantly (P < 0.001) reduced compared to baseline, while cerebral perfusion pressure increased significantly (P < 0.001). The effects of AVP on TOI and THI lasted longer than on Delta CytOx. There were no significant changes with respect to the intracranial pressure throughout the study period. Conclusions: No improvement of cerebral oxygenation was detected after AVP administration in swine with an Intact systemic circulation. In contrast to recently published investigations, AVP provoked a sustained drop in indices of cerebral oxygenation and CBV.