Period-dependent Associations between Hypotension during and for Four Days after Noncardiac Surgery and a Composite of Myocardial Infarction and Death: A Substudy of the POISE-2 Trial.

BACKGROUND: The relative contributions of intraoperative and postoperative hypotension to perioperative morbidity remain unclear. We determined the association between hypotension and a composite of 30-day myocardial infarction and death over three periods: (1) intraoperative, (2) remaining day of surgery, and (3) during the initial four postoperative days. METHODS: This was a substudy of POISE-2, a 10,010-patient factorial-randomized trial of aspirin and clonidine for prevention of myocardial infarction. Clinically important hypotension was defined as systolic blood pressure less than 90 mmHg requiring treatment. Minutes of hypotension was the exposure variable intraoperatively and for the remaining day of surgery, whereas hypotension status was treated as binary variable for postoperative days 1 to 4. We estimated the average relative effect of hypotension across components of the composite using a distinct effect generalized estimating model, adjusting for hypotension during earlier periods. RESULTS: Among 9,765 patients, 42% experienced hypotension, 590 (6.0%) had an infarction, and 116 (1.2%) died within 30 days of surgery. Intraoperatively, the estimated average relative effect across myocardial infarction and mortality was 1.08 (98.3% CI, 1.03, 1.12; P < 0.001) per 10-min increase in hypotension duration. For the remaining day of surgery, the odds ratio was 1.03 (98.3% CI, 1.01, 1.05; P < 0.001) per 10-min increase in hypotension duration. The average relative effect odds ratio was 2.83 (98.3% CI, 1.26, 6.35; P = 0.002) in patients with hypotension during the subsequent four days of hospitalization. CONCLUSIONS: Clinically important hypotension-a potentially modifiable exposure-was significantly associated with a composite of myocardial infarction and death during each of three perioperative periods, even after adjustment for previous hypotension.

The association of perioperative dexamethasone, smoking and alcohol abuse with wound complications after laparotomy.

BACKGROUND: A number of perioperative risk factors may suppress the immune system and contribute to the development of post-operative complications. The association between surgical site infection (SSI) and other wound-related complications resulting from immunosuppression through either perioperative administration of dexamethasone, pre-operative smoking or alcohol abuse is, however, uncertain. METHODS: This study was a post hoc analysis of data from the PROXI randomized trial in 1386 patients who underwent emergency or elective laparotomy. We assessed the associations of use of dexamethasone, smoking status and alcohol abuse with the primary outcome, being a composite of SSI, anastomotic leak, wound dehiscence, burst abdomen and 30-day mortality. RESULTS: The primary outcome occurred in 21% of patients receiving dexamethasone versus 28% of patients not receiving dexamethasone, and this was not statistically significant when adjusting for stratification variables originally used in the PROXI trial [OR 0.90, 95% CI (0.65-1.24)]. In smokers, the primary outcome occurred in 32%, compared with 23% of non-smokers (P = 0.0001). Smokers also had a higher frequency of SSI (25% vs 17%, P < 0.0001) and burst abdomen (3.8% vs 2.4%, P = 0.04). In alcohol abusers, the primary outcome occurred in 48%, compared with 25% in patients who did not abuse alcohol (P = 0.0006). Burst abdomen occurred more commonly in alcohol abusers (15% vs 2.3%, P < 0.0001). CONCLUSION: Perioperative administration of dexamethasone was not significantly associated with SSI or other wound-related complications. Conversely, smoking and alcohol abuse were both significant predictors of the primary outcome consisting of wound-related complications and mortality.