Influence of a Multi-parametric Optimization Strategy for General Anesthesia on Postoperative Morbidity and Mortality

With the increasing aging population demographics and life expectancies, the number of very elderly patients undergoing surgery is rising. Elderly patients constitute an increasingly large proportion of the high-risk surgical group. Cardiac complications and postoperative pulmonary complications are equally prevalent and contribute similarly to morbidity, mortality, and length of hospital stay. Specific optimization strategy of general anesthesia has been tested in high-risk patients undergoing major surgery to improve outcomes. Our hypothesis is that a combined optimization strategy of anesthesia concerning hemodynamic, ventilation, and depth of anesthesia may improve short- and long- term outcome in elderly undergoing high risk surgery.

The population is expanding and aging. With the increasing aging population demographics and life expectancies, the number of very elderly patients (age ≥ 75) undergoing surgery is rising. Elderly patients constitute an increasingly large proportion of the high-risk surgical group. In 2010, patients aged 75 yrs and over represented only 2.1% of patients undergoing high risk surgery in France (PMSI database), but concentrated 27% of in-hospital deaths. Cardiac complications and postoperative pulmonary complications are equally prevalent and contribute similarly to morbidity, mortality, and length of hospital stay. Specific optimization strategy of general anesthesia has been tested in high-risk patients undergoing major surgery to improve outcomes. Meta-analyses have demonstrated that goal directed hemodynamic therapy significantly reduced mortality and surgical complications in high-risk patients. A lung-protective ventilation strategy in high-risk patients undergoing major abdominal surgery was associated with improved clinical outcome. Retrospective studies indicated that a combination of excessive depth of anesthesia, hypotension and low anesthesia requirement resulted in increased mortality. These approaches of peroperative care remain discussed in the literature and have also to be incorporated in the common clinical practice. Moreover, few of these reviews performed a sensitive analysis in the elderly. Whether a multi-parametric optimization strategy of anesthesia including several specific interventions will impact the short-term postoperative major morbidity and mortality in elderly is not known. The addition of depth of anesthesia monitoring to hemodynamic monitoring and goal directed hemodynamic therapy may improve tissue perfusion by reducing hemodynamic side effects of anesthetic agents, particularly in elderly where the therapeutic window of these agents is reduced. The effects of low protective ventilation may also by additive to the previous measures by reducing the perioperative build-up of oxygen debt. Our hypothesis is that a combined optimization strategy of anesthesia concerning hemodynamic, ventilation, and depth of anesthesia may improve short- and long- term outcome in elderly undergoing high risk surgery.