ASA Monitor May 2024, Vol. 88, 26.

Perioperative mortality is most often defined as the rate of death following surgery and anesthesia beginning on the day of surgery and extending to the 30th postoperative day or the day of discharge from the hospital (BR J Anaesth 2015;114:32-42). While this seems to be the most frequent definition, there has been some concern that perioperative mortality at 30 days may underestimate the actual mortality associated with certain surgical procedures (HPB 2011;13:473-82). Tracking perioperative mortality is essential and allows the ability to evaluate and improve surgical services (Lancet 2015;385:S27). Unfortunately, perioperative mortality can be challenging to accurately monitor due to variability in definitions, lack of standardization in collection of mortality data, differing denominators, and unavailable data (Lancet 2015;385:S27).

Mortality attributable to anesthesia alone has improved immensely over the years. In 1954, data presented by Beecher et al. showed the significant impact of anesthesia on perioperative mortality, identifying death from anesthesia as a “public health problem” (Ann Surg 1954;140:2-35). Over the years, there have been reductions in perioperative mortality attributable solely to anesthesia via improvements in technology, advances in monitoring, and better pharmacologic agents (Can Anaesth Soc J 1986;33:336-44; Anaesthesia 2001;56:1141-53; Australian and New Zealand College of Anaesthetists: Safety of Anaesthesia in Australia 2000-2002; Anesthesiology 2009;110:759-65; Anesth Analg 2018;127:730-35).

Perioperative mortality attributed solely to anesthesia is minimal in the modern era (Anesth Analg 2018;127:730-35). Most of these deaths occur in the intraoperative and immediate postoperative period, with etiologies typically due to cardiovascular management, ventilatory management, or patient monitoring (Anaesthesia 2001;56:1141-53). Currently, mortality in the 30 days following surgery is almost 1,000 times greater than anesthesia-related intraoperative mortality (Intensive Care Med 2018;44:811-22). Targeting mortality in the 30 days following surgery presents a way for anesthesiologists to continue to add value to perioperative care. Improving preoperative optimization and reducing postoperative cardiac events have the potential to reduce mortality in the period following surgery.

Preoperative optimization can reduce both intraoperative and postoperative mortality. While the preanesthetic interview is standard prior to proceeding to surgery, the timing is not. This interview often falls during the week of surgery and can even occur on the day of surgery. Unfortunately, scheduled surgery often takes precedence over optimizing modifiable risk factors that are associated with perioperative morbidity and mortality. When the preoperative evaluation is completed close to surgery, the importance of detecting unstable disease becomes the main priority. Excluding case-cancelling conditions, up to 20% of remaining patients seen preoperatively may have unoptimized medical conditions that can worsen surgical outcomes and increase cost (Anesth Analg 2020;130:808-10). Some studies have suggested postponing elective surgery until certain parameters are met due to these worse outcomes, such as transfusion, infection, need for repeat surgery, and mortality (HSS J 2022;18:418-27). Optimizable parameters include obesity, malnutrition, hypoalbuminemia, diabetes, anemia, smoking, and opioid use (HSS J 2022;18:418-27).

The vast majority of surgeries are elective in nature, allowing identification and optimization of high-risk patients. For optimization to occur, the ideal perioperative assessment should occur well in advance of surgery so that intervention on modifiable risk factors can be completed. From a cardiovascular perspective, there are a few areas where optimization can occur. These include prehabilitation, medication management for ischemic heart disease/congestive heart failure/hypertension, anemia optimization, and appropriate interrogation of implantable cardiac devices (Clin Colon Rectal Surg 2023;36:167-74). For those patients with pulmonary disease, preoperative optimization includes smoking cessation, preoperative incentive spirometry, medication management for chronic obstructive pulmonary disease (COPD) and asthma, and compliance with continuous positive airway pressure therapy for patients with obstructive sleep apnea (Clin Colon Rectal Surg 2023;36:167-74). Additionally, at the preoperative appointment, severe disease exacerbations can be identified and necessary delays to elective and semi-elective procedures can be determined prior to the day of surgery (recent myocardial infarction, recent percutaneous coronary intervention, congestive heart failure exacerbation, COPD exacerbation, recent stroke, recent infection) (Clin Colon Rectal Surg 2023;36:167-74). Overall, early identification of comorbid conditions allows for the reduction in day-of-surgery cancellations and improvement in the patient’s status prior to surgical procedures.

The postoperative period offers another opportunity for reducing perioperative mortality. Heart disease continues to be the leading cause of death for most groups of people in the United States, with coronary artery disease being the most common etiology ( Perioperative myocardial injury (PMI) is a complication following noncardiac surgery that is strongly associated with 30-day mortality (Circulation 2018;137:1221-32). In one study, the incidence of PMI was found to be 16% in high-risk patients (Circulation 2018;137:1221-32). Patients with PMI had a 30-day mortality of 9.8% compared with 1.6% of those without PMI (Circulation 2018;137:1221-32). Furthermore, the one-year mortality was also higher in the PMI group, 22% versus 9.3% (Circulation 2018;137:1221-32). Myocardial injury after noncardiac surgery (MINS) is a clinical diagnosis first described in 2014. It is defined as myocardial cell injury during or within 30 days from noncardiac surgery (Curr Opin Anaesthesiol 2021;34:381-6). The majority of MINS has been attributed to oxygen supply-demand mismatch. Most presentations of MINS are silent in nature and require cardiac biomarker measurements for identification (Curr Opin Anaesthesiol 2021;34:381-6). After identification of MINS, interventions can be pursued to reduce the mortality risk associated with it. Interventions can include smoking cessation, increased physical activity, improvements in diet, earlier postdischarge visits, cardiology consultations, and pharmacologic therapy (Curr Opin Anaesthesiol 2021;34:381-6). Both aspirin and statin administration can be considered in attempts to reduce mortality in patients with MINS (Sci Rep 2020;10:11616; Ann Intern Med 2011;154:523-8). The American Heart Association advocates serial troponin measurements in high-risk patients so that MINS can be appropriately identified and treated (Circulation 2021;144:e287-e305). The involvement and awareness of anesthesiologists in the development, implementation, and improvement of MINS protocols can help improve patient outcomes and reduce perioperative mortality.

Advancements in anesthetic care have reduced intraoperative and immediate postoperative mortality. Morbidity and mortality in the 30 days following surgery is an area where anesthesiologists can continue to add value to perioperative care. There are a multitude of ways this can be accomplished, ranging from early preoperative anesthesia consultation and optimization to reduction in postoperative cardiac events.