Perioperative mortality is one of the most important problems the surgical community must face. Perioperative mortality ranges from 0.1% to as high as 27–30%, depending on the type of surgery. [8, 9]. Gastrointestinal and hepatobiliary surgery is technically demanding procedures and has among the highest perioperative mortality rates. [10, 11, 12]. Another issue is surgeons rarely audit their mortality data scientifically and in-process rarely know what factors might be responsible for poor outcomes in their patients.
This study aimed to do a mortality audit for patients operated for gastrointestinal and hepatobiliary surgeries in our department and study factors responsible for 90 days and in-hospital mortality.
Our elective 90 days and in-hospital mortality rates after elective surgeries were around 3.2% and 2.3% respectively and 18% and 15.2% respectively, which is comparable to what Sørensen et al. [12] described in their study. They showed 30 days mortality of 2.8% and 13% respectively in elective and emergency surgeries.
Our overall 90 days and in-hospital mortality rates were 5.6% and 4.2% which were comparable to published literature. [13].
We chose to study 90 days mortality instead of 30 days mortality as mayo et al [14] described 90 days mortality should be the standard criteria to describe perioperative mortality.
As we have described in results various factors were associated with 90 days and in-hospital mortality but on multivariate analysis nontechnical complications, age and emergency surgery independently predicted both 90 days and in-hospital mortality. Post-operative acute kidney injury was associated with in-hospital mortality independently however it was not associated with 90 days mortality after multivariate analysis which may imply that patients who recovered from post-operative acute kidney injury did well subsequently.
90 days mortality and in-hospital mortality in major surgeries in our series were 6.7% and 4.8% respectively. Major surgery was not independently associated with 90 days or in-hospital mortality after multivariate analysis. Heyer et al [15] in their recently published study consisting of a large cohort of complex gastrointestinal surgeries showed textbook outcomes are increased over time, they showed 90 days mortality of around 9.2% in a cohort of more than 31000 patients operated between 2014–2016. In our series complex, gastrointestinal surgery for malignancy showed similar results of 9.3% 90 days mortality and 5.3% in-hospital mortality. However, surgery for the malignant disease was not associated with 90 days or in-hospital mortality.
Type of surgery like liver resections or transplants, HPB surgery, upper gastrointestinal surgery, small intestinal surgeries, colorectal surgeries, hernia, and other surgeries were not associated with 90 days or in-hospital mortality. Colorectal surgery was not associated with 90 days mortality, it was associated with in-hospital mortality on univariate analysis but failed to show association on multivariate analysis.
Surgeons are always worried about the technical aspects of surgery, although very few studies have been carried out that looked at the impact of non-technical complications on perioperative mortality. There are various perioperative complications, which are not related to surgical techniques and depend on many factors, such as patients' preoperative conditions perioperative course of anesthesia, pathophysiologic response to surgical stress, etc. These complications can include, but are not limited to, acute kidney injury, ARDS, postoperative delirium, myocardial infarction, and postoperative acute left ventricular dysfunction. These complications contribute significantly to overall mortality. [16, 17]
In our series, nontechnical complications were independently associated with 90 days and in-hospital mortality after multivariate logistic regression analysis and their strength of associated was very high with odds ratios of 61.15 and 94.23 respectively for 90 days and in-hospital mortality, suggesting the need to concentrate on preoperative, intraoperative, and postoperative critical care management to prevent and treat such complications. Pre and intraoperative factors like CDC grading of wound classification, American society of anesthesia score, number of blood transfusions, duration of surgery predicted 90 days, and in-hospital mortality on univariate analysis but failed to show independent association on multivariate analysis and they might have some role to play in the development of nontechnical complications.
Technical complications like intraoperative bleeding, anastomotic leaks, or bile leaks have no association with in-hospital mortality. Anastomotic leaks and bile leaks had an association with 90 days mortality on univariate analysis but had no independent association after multivariate analysis. It again showed the importance of perioperative critical care management to reduce mortality.
Age and Emergency surgeries also predicted both 90 days and in-hospital mortality independently. However, Age had weak strength of association with an odds ratio of 1.07 and 1.09 for 90 days and in-hospital mortality respectively.
Logistic regression looked at 90 days mortality on multivariate analysis, we also analyzed time to the event by cox regression analysis which showed similar results, and age, emergency surgeries, and non-technical complications were associated with worse survival over 90 days. Figure 1 showed on Kaplan Meier analysis non-technical complications were associated with significantly worse 90 days survival.
There are certain limitations of this study, as being a retrospective analysis there can be inherent limitations of retrospective analysis like selection bias. However, data was maintained prospectively. There can be other factors affecting mortality that could not be included in the analysis. The sample size was small as can be seen from the wider confidence interval. Our unit being predominantly Hepatopancreatic biliary surgery (HPB) unit in this analysis HPB surgeries outnumbered the other surgeries. The strength of the study is that it is one of the few studies showing strong strength of association with postoperative nontechnical complications with postoperative mortality.
In conclusion, Age, non-technical complications, open surgery, and emergency surgeries are independently associated with 90 days mortality, and age, acute kidney injury, non-procedural complications, and emergency surgery independently predicts in-hospital mortality.