Effects of an alveolar recruitment maneuver on subdural pressure, brain swelling, and mean arterial pressure in patients undergoing supratentorial tumour resection: a randomized crossover study.
OBJECTIVE
Although recruitment maneuvers have been advocated as part of a lung protective ventilation strategy, their effects on cerebral physiology during elective neurosurgery are unknown. Our objectives were to determine the effects of an alveolar recruitment maneuver on subdural pressure (SDP), brain relaxation score (BRS), and cerebral perfusion pressure among patients undergoing supratentorial tumour resection.


METHODS
In this prospective crossover study, patients scheduled for resection of a supratentorial brain tumour were randomized to undergo either a recruitment maneuver (30 cm of water for 30 sec) or a "sham" maneuver (5 cm of water for 30 sec), followed by the alternative intervention after a 90-sec equilibration period. Subdural pressure was measured through a dural perforation following opening of the cranium. Subdural pressure and mean arterial pressure (MAP) were recorded continuously. The blinded neurosurgeon provided a BRS at baseline and at the end of each intervention. During each treatment, the changes in SDP, BRS, and MAP were compared.


RESULTS
Twenty-one patients underwent the study procedure. The increase in SDP was higher during the recruitment maneuver than during the sham maneuver (difference, 3.9 mmHg; 95% confidence interval [CI], 2.2 to 5.6; P < 0.001). Mean arterial pressure decreased further in the recruitment maneuver than in the sham maneuver (difference, -9.0 mmHg; 95% CI, -12.5 to -5.6; P < 0.001). Cerebral perfusion pressure decreased 14 mmHg (95% CI, 4 to 24) during the recruitment maneuver. The BRS did not change with either maneuver.


CONCLUSIONS
Our results suggest that recruitment maneuvers increase subdural pressure and reduce cerebral perfusion pressure, although the clinical importance of these findings is thus far unknown. This trial was registered with ClinicalTrials.gov, NCT02093117.
Department of Anesthesiology, Pharmacology and Therapeutics, Vancouver General Hospital, University of British Columbia, Room 2449 JPP 899 West 12th Avenue, Vancouver, BC, V5Z 1M9, Canada. alana.flexman@vch.ca.
Alana M
AM
Flexman
Division of Neurosurgery, Department of Surgery, University of British Columbia, Vancouver, BC, Canada.
Peter A
PA
Gooderham
Department of Anesthesiology, Pharmacology and Therapeutics, Vancouver General Hospital, University of British Columbia, Room 2449 JPP 899 West 12th Avenue, Vancouver, BC, V5Z 1M9, Canada.
Donald E
DE
Griesdale
Vancouver Coastal Health Research Institute, Vancouver, BC, Canada.|Wellcome Trust HRB Clinical Research Facility, St. James's Hospital, H&H Building, Level 2, Dublin 8, Ireland.
Ruth
R
Argue
Division of Neurosurgery, Department of Surgery, University of British Columbia, Vancouver, BC, Canada.
Brian
B
Toyota
D000328:Adult; D000368:Aged; D062186:Arterial Pressure / Q000502:physiology; D001929:Brain Edema / Q000453:epidemiology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000379:methods*; D011175:Positive-Pressure Respiration; D011446:Prospective Studies; D011650:Pulmonary Alveoli / Q000502:physiology*; D015173:Supratentorial Neoplasms / Q000601:surgery*