Concurrence of Intraoperative Hypotension, Low Minimum Alveolar Concentration, and Low Bispectral Index Is Associated with Postoperative Death.
BACKGROUND
An intraoperative concurrence of mean arterial pressure less than 75 mmHg, minimum alveolar concentration less than 0.8, and bispectral index less than 45 has been termed a "triple low" state. An association between triple low and postoperative mortality has been reported but was not replicated in a subsequent study. The authors pooled existing data from clinical trials to further evaluate the purported association in an observational study.


METHODS
This retrospective observational study included 13,198 patients from three clinical trials: B-Unaware, BAG-RECALL, and Michigan Awareness Control Study. Patients with greater than 15 not necessarily consecutive minutes of triple low were propensity matched to controls with similar characteristics and comorbidities. A multivariable Cox proportional hazards model was used to evaluate the association between triple low duration and postoperative mortality.


RESULTS
Thirty-day mortality was 0.8% overall, 1.9% in the triple low cohort, and 0.4% in the nontriple low cohort (odds ratio, 5.16; 95% CI, 4.21 to 6.34). After matching and adjusting for comorbidities, cumulative duration of triple low was significantly associated with an increased risk of mortality at 30 days (hazard ratio, 1.09; 95% CI, 1.07 to 1.11, per 15 min) and 90 days (hazard ratio, 1.09; 95% CI, 1.08 to 1.11, per 15 min).


CONCLUSIONS
There is a weak independent association between the triple low state and postoperative mortality, and the propensity-matched analysis does not suggest that this is an epiphenomenon.
From the Department of Anesthesiology, Washington University in Saint Louis School of Medicine, St. Louis, Missouri (M.D.W., M.S.A.); Department of Anesthesiology, University of Utah Medical School, Salt Lake City, Utah (E.K.); Center for Perioperative Outcomes Research, and Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, Michigan (A.M.S., S.K.); Department of Anesthesiology, University of Chicago, Chicago, Illinois (M.F.O.); and Department of Anesthesiology, University of Manitoba, Winnipeg, Manitoba, Canada (E.J.).
Mark D
MD
Willingham
Elliott
E
Karren
Amy M
AM
Shanks
Michael F
MF
O'Connor
Eric
E
Jacobsohn
Sachin
S
Kheterpal
Michael S
MS
Avidan
D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D056805:Consciousness Monitors; D007022:Hypotension / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology; D007431:Intraoperative Complications / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology; D016343:Monitoring, Intraoperative / Q000379:methods; D011183:Postoperative Complications / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology; D011650:Pulmonary Alveoli / Q000503:physiopathology; D012189:Retrospective Studies; D002986:Clinical Trials as Topic