Neurosurgery Recruitment Maneuver Study
Condition: Subdural Pressure During Supratentorial Brain Tumour Resection
MeSH terms: Brain Neoplasms
Study type: Interventional

Summary: 
      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).
    


Intervention name(s): Recruitment maneuver; Sham recruitment maneuver
Intervention type(s): Procedure; Procedure
Intervention description(s): continuous positive airway pressure of 30 cm of water for 30 seconds; Continuous positive airway pressure of 5 cm of water for 30 seconds
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Treatment
Keywords: Supratentorial neurosurgery; Recruitment maneuver; Subdural pressure; Brain relaxation; Cerebral perfusion pressure