Subdural Pressure During Supratentorial Brain Tumour Resection Clinical Trial
Official title:
Effect of an Alveolar Recruitment Maneuver on Subdural Pressure, Brain Swelling and Cerebral Perfusion Pressure in Patients Undergoing Supratentorial Tumour Resection
Background. Patients undergoing neurosurgical procedures experience higher rates of
postoperative respiratory failure compared to the broader surgical population.
Lung-protective ventilation strategies, including alveolar recruitment maneuvers may be
beneficial. Despite this potential benefit, the effect of high levels of continuous airway
pressure on intracranial pressure, brain swelling and cerebral perfusion must be defined
prior to applying this intervention to the neurosurgical population.
Objectives. The primary objective is to determine the effect of an alveolar recruitment
maneuver on subdural pressure in patients undergoing supratentorial tumour resection. The
secondary objectives are to determine the effect of an alveolar recruitment maneuver on 1)
brain bulk score and 2) cerebral perfusion pressure in patients undergoing supratentorial
tumour resection.
Hypothesis. The investigators hypothesize that an alveolar recruitment maneuver of 30 cm of
water over 30 seconds will not result in a clinically-important (>3 mmHg) increase in
subdural pressure.
Methods. This single center, randomized, cross-over study will enroll 30 American Society of
Anesthesiologists Classification I-III patients scheduled to undergo supratentorial brain
tumour resection at Vancouver General Hospital. All patients will receive a standardized
general anesthetic including invasive blood pressure monitoring. After removal of the bone
flap, subdural pressure will be measured using a sterile 22-gauge plastic cannula. Brain bulk
will be assessed using a validated 4-point scale. After baseline arterial and subdural
pressure determination and brain swelling assessments, patients will be randomized to receive
either a recruitment maneuver of 30 cm of water for 30 seconds or a sham recruitment maneuver
of 5 cm of water for 30 seconds. Maximal subdural pressure and minimum mean arterial pressure
during the maneuver will be noted, and the neurosurgeon will be asked to score the brain
bulk. After a 2-minute equilibration period, the protocol will be repeated with the alternate
group allocation.
Statistical Analysis. Our sample size calculation, based on our primary outcome (subdural
pressure), determined that a sample size of 22 patients would allow us to detect a difference
of 3.5 mmHg in subdural pressure assuming a type I error of 0.05, a type II error of 0.2 and
two-sided significance testing. The subdural pressure during the recruitment maneuver as
compared to the sham maneuver will be analyzed using a paired t-test. The brain bulk score
will be compared using a Wilcoxon signed rank test. All data analysis will be performed with
STATA 12.1 (StataCorp, College Station, TX).
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