Incidence, Risk Factors, and Outcomes of Postoperative Hypoxemic Respiratory Failure following Emergency Surgical Procedures at the causality theatre, Mulago National Referral Hospital.

Abstract

Introduction: Postoperative hypoxemic respiratory failure (PHRF) is a significant cause of morbidity and mortality in emergency surgery and anesthesia [1]. Identifying patients at risk for PHRF is important for better patient outcomes. There is however little data describing the burden of PHRF and its risk factors in low-resource- setting such as Uganda. This study aimed to determine the incidence, risk factors, and outcomes of postoperative hypoxemic respiratory failure following emergency surgical procedures at the causality theatre, Mulago National Referral Hospital (MNRH). Methods:Patients who underwent emergency surgery at the causality theatre of MNRH between March and April 2022 were assessed for PHRF within the first 5 days of postoperative. Background data were collected using questionnaires and medical records to assess risk factors. The patients were then followed up for 28 days post-operative to assess mortality. Analysis was done using Stata version 15 and Poisson regression was done to assess the risk factors for PHRF. Results: Out of 389 participants recruited, 345 participants had their data analyzed. 78.3% were male and the mean age of the participants was 39.0 years. 14.5% developed PHRF within the first five postoperative days which was the overall incidence of PHRF. At multivariate analysis, four factors were significantly associated with the incidence of PHRF, that is, ASA score > 2 with a ninefold risk (8.58, 3.75-19.62, p <0.001), cigarette smoking with a fourfold risk (4.20, 2.03-8.71, p<0.001), estimated blood loss of over 100mls with a threefold risk (2.5, 1.59- 4.54, p < 0.001), and presence of a nasogastric tube preoperatively with a fivefold risk (5.20, 2.31-11.69, p<0.001). The mean hospital length of stay was substantially prolonged for those with PHRF within the first five days of surgery; 13 days’ vs 5 days in those without. The overall mortality on day 28 was 1 death per 1000 days of observation in those without PHRF vs. 40 deaths per 1000 days of observation in patients who developed PHRF. Conclusions: PHRF is common within the first 5 days of post-operative with a high incidence rate of 14.5% following emergency surgery. Close monitoring of emergency surgical patients especially those with a smoking history, high blood loss, ASA score >2, or using a nasogastric tube preoperatively to allow early recognition and treatment of PHRF may reduce the risk of death.