Effect of Controlled Hypotension on Cerebral Oxygen Saturation
Status:
Completed
Trial end date:
2017-08-01
Target enrollment:
Participant gender:
Summary
For a successful functional endoscopic sinus surgery (FESS), it is crucial to provide
effective controlled hypotension to reduce blood loss and provide a relatively blood-free
surgical environment to facilitate surgery.
The goal of controlled hypotension is to maintain an arterial blood pressure which is
sufficiently low to allow a reduction in bleeding with offering a superior intraoperative
hemodynamic stability during stressful surgical events to maintain intact cerebral
microcirculatory auto-regulation.
Auto-regulation impairment during controlled hypotension might increase oxygen extraction
ratio. Thus monitoring the cerebral oxygen saturation (rSO2) to measure cerebral oxygenation
becomes essential and it remains a challenge to clinically assess cerebral oxygenation on a
routine basis.
Various recent studies reported based on facilitating the induction of controlled
hypotension, but the effects of hypotension on cerebral perfusion and oxygenation and its
effects on postoperative cognitive function are still poorly characterized. Moreover, the
relationship between rSO2 and controlled hypotension has not been established in patients
undergoing FESS.
Within the last decade, near infrared spectroscopy (NIRS) INVOS® monitors which is clinically
most broadly spread technique, can be used for non-invasive assessment of cerebral perfusion
by detecting changes in rSO2 by online monitoring of cerebral oxygenation.
In our clinical routine for achieving a controlled hypotension, esmolol and remifentanyl are
the most commonly used hypotensive agents. The aim of this prospective randomized single
blind study was to investigate the influence of remifentanyl as a hypotensive agent in
comparison to esmolol on rSO2 by using NIRS and postoperative cognitive function in patients
undergoing FESS.