Purpose
Enhanced Recovery After Surgery (ERAS) programs have increasingly attracted the attention of clinicians who are intent on minimizing postoperative morbidity, decreasing variability in ...surgical care, and containing hospital costs. The purpose of this review is to discuss the relevant pathophysiology of the surgical stress response and its associated mechanisms that regulate important metabolic changes.
Principal findings
The combination of hormonal release and various inflammatory responses inherent in the stress response to surgery contributes to a state of insulin resistance that represents one of the main pathogenic factors modulating perioperative outcome. The consequence of a decrease in insulin sensitivity is a significant change in protein and glucose metabolism characterized by an increase in the production of endogenous hepatic glucose, a decrease in the uptake of peripheral glucose, and an increase in the breakdown of protein. Muscle is the main tissue for uptake of insulin-mediated glucose, and consequent with the reduced activation of a specific glucose transporter protein (GLUT 4), glucose cannot be transported into the muscle cells. Consequently, breakdown of muscle protein, also related to insulin resistance, occurs to supply amino acids for gluconeogenesis, thus leading to the overall loss of lean muscle tissue. Besides the metabolic changes associated with the surgical insult, pain, relative perioperative starvation, and poor mobilization further contribute to a loss of insulin sensitivity and an increased catabolic state. Many of the ERAS elements that are implemented, including perioperative feeding, epidural analgesia, and minimally invasive surgery, modulate the stress response, promote insulin sensitivity, and attenuate the breakdown of protein.
Conclusions
The implementation of a targeted ERAS program has been shown to modulate perioperative insulin sensitivity, thus improving postoperative outcomes and accelerating the return of baseline function.
Surgery represents a major stressor that disrupts homeostasis and can lead to loss of body cell mass. Integrated, multidisciplinary medical strategies, including enhanced recovery programs and ...perioperative nutrition support, can mitigate the surgically induced metabolic response, promoting optimal patient recovery following major surgery. Clinical therapies should identify those who are poorly nourished before surgery and aim to attenuate catabolism while preserving the processes that promote recovery and immunoprotection after surgery. This review will address the impact of surgery on intermediary metabolism and describe the clinical consequences that ensue. It will also focus on the role of perioperative nutrition, including preoperative nutrition risk, carbohydrate loading, and early initiation of oral feeding (centered on macronutrients) in modulating surgical stress, as well as highlight the contribution of the anesthesiologist to nutritional care. Emerging therapeutic concepts such as preoperative glycemic control and prehabilitation will be discussed.
This narrative review presents a biological rationale and evidence to describe how the preoperative condition of the patient contributes to postoperative morbidity. Any preoperative condition that ...prevents a patient from tolerating the physiological stress of surgery (e.g. poor cardiopulmonary reserve, sarcopaenia), impairs the stress response (e.g. malnutrition, frailty), and/or augments the catabolic response to stress (e.g. insulin resistance) is a risk factor for poor surgical outcomes. Prehabilitation interventions that include exercise, nutrition, and psychosocial components can be applied before surgery to strengthen physiological reserve and enhance functional capacity, which, in turn, supports recovery through attaining surgical resilience. Prehabilitation complements Enhanced Recovery After Surgery (ERAS) care to achieve optimal patient outcomes because recovery is not a passive process and it begins preoperatively.
Cancer and its treatments are associated with functional decline that has impactful consequences on quality of life, and care continuum. Thus, optimizing perioperative functional capacity has been ...identified as a research and clinical priority in cancer care. The process of enhancing physical fitness before an operation to enable the patient to withstand the stress of surgery has been termed prehabilitation. Main elements are preoperative exercise, nutrition therapy, and anxiety-reduction techniques. Given the growing body of evidence on prehabilitation efficacy, this narrative review will summarize the rational underlying preoperative interventions, and propose a structured clinical pathway aimed at optimizing preoperative functional capacity.
Traditional rehabilitative approaches to perioperative cancer care have focused on the postoperative period to facilitate the return to presurgical baseline conditions. However, there is some ...realization that the preoperative period can be a very effective time for intervention as the patients are more amenable to target their physiological condition to prepare to overcome the metabolic cost of the surgical stress.
We undertook a narrative review of the current literature on surgical prehabilitation and discussed the current evidence of preoperative interventions before cancer surgery in order to increase physiological reserve before surgery and accelerate postoperative recovery.
Published data indicate the positive impact of prehabilitation on postoperative functional capacity and return to daily activities. However, the current evidence on the impact on short- and long-term clinical outcome is limited, and more research needs to be conducted.
Preliminary findings indicate that a group of interventions such as exercise, nutrition and anxiety reduction in the preoperative period can complement the enhanced recovery program and facilitate the return to baseline activities of daily living. It is not clear at this stage whether the preoperative increase in functional capacity mitigates the burden of postoperative morbidities and subsequent cancer therapies. Therefore, more research is warranted.
Multimodal prehabilitation is a preoperative conditioning intervention in form of exercise, nutritional assessment, whey protein supplementation, and anxiety-coping technique. Despite recent evidence ...suggesting that prehabilitation could improve functional capacity in patients undergoing colorectal surgery for cancer, all studies were characterized by a relatively small sample size. The aim of this study was to confirm what was previously found in three small population trials.
Data of 185 participants enrolled in a pilot single group study and two randomized control trials conducted at the McGill University Health Center from 2010 to 2015 were reanalyzed. Subjects performing trimodal prehabilitation (exercise, nutrition, and coping strategies for anxiety) were compared to the patients who underwent the trimodal program only after surgery (rehabilitation/control group). Functional capacity was assessed with the six-minute walk test (6MWT), a measure of the distance walked over six minutes (6MWD). A significant functional improvement was defined as an increase in 6MWD from baseline by at least 19 m. Changes in 6MWD before surgery, at four and eight weeks were compared between groups.
Of the total study population, 113 subjects (61%) underwent prehabilitation. Changes in 6MWD in the prehabilitation group were higher compared to the rehabilitation/control group during the preoperative period {30.0 standard deviation (SD) 46.7 m vs. -5.8 (SD 40.1) m, p < 0.001}, at four weeks -11.2 (SD 72) m vs. -72.5 (SD 129) m, p < 0.01, and at eight weeks 17.0 (SD 84.0) m vs. -8.8 (SD 74.0) m, p = 0.047. The proportion of subjects experiencing a significant preoperative improvement in physical fitness was higher in those patients who underwent prehabilitation 68 (60%) vs. 15 (21%), p < 0.001.
In large secondary analysis, multimodal prehabilitation resulted in greater improvement in walking capacity throughout the whole perioperative period when compared to rehabilitation started after surgery.
Background Abdominal surgery represents a physiologic stress and is associated with a period of recovery during which functional capacity is often diminished. “Prehabilitation” is a program to ...increase functional capacity in anticipation of an upcoming stressor. We reported recently the results of a randomized trial comparing 2 prehabilitation programs before colorectal surgery (stationary cycling plus weight training versus a recommendation to increase walking coupled with breathing exercises); however, adherence to the programs was low. The objectives of this study were to estimate: (1) the extent to which physical function could be improved with either prehabilitation program and identify variables associated with response; and (2) the impact of change in preoperative function on postoperative recovery. Methods This study involved a reanalysis of data arising from a randomized trial. The primary outcome measure was functional walking capacity measured by the Six-Minute Walk Test; secondary outcomes were anxiety, depression, health-related quality of life, and complications (Clavien classification). Multiple linear regression was used to estimate the extent to which key variables predicted change in functional walking capacity over the prehabilitation and follow-up periods. Results We included 95 people who completed the prehabilitation phase (median, 38 days; interquartile range, 22–60), and 75 who were also evaluated postoperatively (mean, 9 weeks). During prehabilitation, 33% improved their physical function, 38% stayed within 20 m of their baseline score, and 29% deteriorated. Among those who improved, mental health, vitality, self-perceived health, and peak exercise capacity also increased significantly. Women were less likely to improve; low baseline walking capacity, anxiety, and the belief that fitness aids recovery were associated with improvements during prehabilitation. In the postoperative phase, the patients who had improved during prehabilitation were also more likely to have recovered to their baseline walking capacity than those with no change or deterioration (77% vs 59% and 32%; P = .0007). Patients who deteriorated were at greater risk of complications requiring reoperation and/or intensive care management. Significant predictors of poorer recovery included deterioration during prehabilitation, age >75 years, high anxiety, complications requiring intervention, and timing of follow-up assessment. Conclusion In a group of patients undergoing scheduled colorectal surgery, meaningful changes in functional capacity can be achieved over several weeks of prehabilitation. Patients and those who care for them, especially those with poor physical capacity, should consider a prehabilitation regimen to enhance functional exercise capacity before colectomy.
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