Strategies to attenuate the catabolic response to surgery and improve perioperative outcomes

Real-time ultrasound guided thoracic epidural catheterization: a technical review

Thoracic epidural analgesia is known to have superior perioperative pain control over intravenous opioid analgesia in open abdominal surgery and is an essential enhanced recovery after surgery component in major abdominal surgeries. Recently, the ultrasound-guided thoracic epidural catheter placement (TECP) technique has drawn attention as an alternative for the traditional landmark palpation-based TECP or fluoroscopic-guided TECP technique due to the equipment's improvement and increased popularity. However, only a small number of studies have introduced the advantages and usefulness of ultrasound-guided TECP. Moreover, a certain level of ultrasound-guided in-plane technique is required to perform this technique. Thus, to apply ultrasound-guided TECP correctly and reduce the likelihood of side effects and complications, the practitioner must have a thorough understanding of the anatomical region, optimal block positioning, device selection, and management. In this technical review, the authors have compared the advantages and disadvantages of ultrasound-guided TECP to traditional techniques and described its technical aspects from patient positioning, ultrasound probe selection and scanning, needle insertion under ultrasound guidance, and successful thoracic epidural catheter insertion confirmation through ultrasound imaging. Additionally, the recommended epidural catheter tip placement level with the extent of its injectate epidural spread is further described in this review in reference to a recent prospective study published by the authors.

Nutritional Considerations and Strategies to Facilitate Injury Recovery and Rehabilitation

Nutritional interventions are not commonly a standard of care in rehabilitation interventions. A nutritional approach has the potential to be a low-cost, high-volume strategy that complements the existing standard of care. In this commentary, our aim is to provide an evidence-based, practical guide for athletes with injuries treated surgically or conservatively, along with healing and rehabilitation considerations. Injuries are a normal and expected part of exercise participation. Regardless of severity, an injury typically results in the athlete's short- or long-term removal from participation. Nutritional interventions may augment the recovery process and support optimal healing; therefore, incorporating nutritional strategies is important at each stage of the healing process. Preoperative nutrition and nutritional demands during rehabilitation are key factors to consider. The physiological response to wounds, immobilization, and traumatic brain injuries may be improved by optimizing macronutrient composition, caloric consumption, and nutrient timing and using select dietary supplements. Previous research supports practical nutrition recommendations to reduce surgical complications, minimize deficits after immobilization, and maximize the chance of safe return to play. These recommendations include identifying the individual's caloric requirements to ensure that energy needs are being met. A higher protein intake, with special attention to evenly distributed consumption throughout the day, will help to minimize loss of muscle and strength during immobilization. Dietary-supplement strategies may be useful when navigating the challenges of appropriate caloric intake and timing and a reduced appetite. The rehabilitation process also requires a strong nutritional plan to enhance recovery from injury. Athletic trainers, physical therapists, and other health care professionals should provide basic nutritional recommendations during rehabilitation, discuss the timing of meals with respect to therapy, and refer the patient to a registered dietitian if warranted. Because nutrition plays an essential role in injury recovery and rehabilitation, nutritional interventions should become a component of standard-of-care practice after injury. In this article, we address best practices for implementing nutritional strategies among patients with athletic injuries.

Effect of Perioperative Nutritional Supplementation on Postoperative Complications-Systematic Review and Meta-Analysis

BACKGROUND

Perioperative carbohydrate loading, increased protein intake, and immunonutrition may decrease postoperative complications. Studies on the topic have led to controversial results.

METHODS

We searched Medline, EMBASE, and CENTRAL up to August 2018 for randomized trials comparing the effect of perioperative nutritional supplements (intervention) versus control on postoperative complications in patients undergoing gastrointestinal cancer surgery. Secondary outcomes included infectious complications and length of hospital stay (LOS). Random effects model was used to estimate the pooled risk ratio (RR) of treatment effects. Pooled mean difference (MD) was used to compare LOS. Heterogeneity was assessed using I². Sources of heterogeneity were explored through subgroup analysis by nutritional supplementation protocol, type of surgery, and type of nutritional supplement. Risk of bias and quality of the evidence were assessed.

RESULTS

Of 3951 articles, we identified 56 trials (n = 6370). Perioperative nutrition was associated with a lower risk of postoperative complications (RR 0.74, 95% confidence interval (CI) 0.69-0.80); postoperative infections (RR 0.71, 95% CI 0.64-0.79, n = 4582); and postoperative non-infectious complications (RR 0.79, 95% CI 0.71-0.87, n = 4883). There were no significant heterogeneity outcomes analyzed (I² = 14%, 1%, and 7%, respectively). LOS was shorter for the intervention group, MD - 1.58 days; 95% CI - 1.83 to - 1.32; I² = 89%). Subgroup analysis did not identify sources of heterogeneity. The quality of evidence for postoperative complications was high and for LOS was moderate.

CONCLUSION

Perioperative nutritional optimization decreases the risk of postoperative infectious and non-infectious complications. It also decreases LOS in patients undergoing gastrointestinal cancer surgery, but these findings should be taken with caution given the high heterogeneity.

Nutritional prehabilitation: physiological basis and clinical evidence

In this narrative review, we describe the physiological basis for nutritional prehabilitation and evaluate the clinical evidence for its current roles in the perioperative period. Surgical stress and fasting induce insulin resistance as a result of altered mitochondrial function. Insulin resistance in the perioperative period leads to increased morbidity in a dose-dependent fashion, while preoperative carbohydrate loading attenuates insulin resistance, minimises protein loss and improves postoperative muscle function. Carbohydrate loading is an established practice in many countries and a key component of enhanced recovery after surgery (ERAS) programs, yet its independent effects on clinical outcomes remain unclear. Amino acid supplements may confer additional positive effects on a number of markers of clinical outcomes in the perioperative period, but their current role is also poorly defined. Clinical studies evaluating nutritional interventions have been marred by conflicting data, which may be due to small sample sizes, as well as heterogeneity of patients and surgical procedures. At present, it is known that carbohydrate loading is safe and improves patients' wellbeing, but does not appear to influence length of hospital stay or rate of postoperative complications. This should be appreciated before its routine inclusion in ERAS programs.

Hyperinsulinemic-normoglycemic clamp administered together with amino acids induces anabolism after cardiac surgery

Cardiac surgery triggers an inflammatory stress response, leading to protein catabolism, a process that even high-dose insulin therapy alone cannot reverse. To determine whether hyperinsulinemic-normoglycemic clamp and perioperative amino acid (AA) supplementation improves whole body protein balance, 20 patients scheduled for elective coronary artery bypass grafting surgery were randomly assigned to have intra- and postoperative hyperinsulinemic-normoglycemic clamp, with or without intravenous AA supplementation. Primed continuous infusions of [6,6-²H₂]glucose and l-[1-¹³C]leucine were used to quantify whole body protein and glucose metabolism before and after surgery. Adipose tissue and serum cytokines were also analyzed to measure their responsiveness to the anabolic effect of AA administration. During hyperinsulinemic-normoglycemic clamp, AA supplementation successfully stimulated whole body protein synthesis, resulting in a positive whole body protein balance after surgery (insulin: -13.6 ± 4.5 vs. insulin + AA: 2.1 ± 5.4 μmol·kg^-1·h^-1, P < 0.001). Endogenous glucose production was equally suppressed in both groups (insulin: 0.0 ± 3.8 vs. insulin + AA 1.6 ± 1.6 μmol·kg^-1·min^-1, P = 0.230). AA supplementation led to significant changes in serum and tissue IL-6 (insulin: 246.6 ± 111.2 vs. insulin + AA: 124.5 ± 79.3 pg/ml, P = 0.011). In conclusion, hyperinsulinemic-normoglycemic clamp technique, together with AA supplementation, can induce an anabolic state after open-heart surgery, as quantified by a positive whole body protein balance.

Enhanced Recovery After Surgery (ERAS) for gastrointestinal surgery, part 1: pathophysiological considerations

BACKGROUND

The present article has been written to convey concepts of anaesthetic care within the context of an Enhanced Recovery After Surgery (ERAS) programme, thus aligning the practice of anaesthesia with the care delivered by the surgical team before, during and after surgery.

METHODS

The physiological principles supporting the implementation of the ERAS programmes in patients undergoing major abdominal procedures are reviewed using an updated literature search and discussed by a multidisciplinary group composed of anaesthesiologists and surgeons with the aim to improve perioperative care.

RESULTS

The pathophysiology of some key perioperative elements disturbing the homoeostatic mechanisms such as insulin resistance, ileus and pain is here discussed.

CONCLUSIONS

Evidence-based strategies aimed at controlling the disruption of homoeostasis need to be evaluated in the context of ERAS programmes. Anaesthesiologists could, therefore, play a crucial role in facilitating the recovery process.

Cortisol and Insulin Levels during Major Gynaecological Operations: The influence of Two Anaesthetic Techniques

BACKGROUND: Metabolic and hormonal changes are noticed within the first few hours after surgical injury. These changes are influenced by the intensity, duration, type of injury, and the anaesthetic techniques.AIM: To investigate the effects of anaesthesia on cortisol, insulin and glucose concentrations during major gynaecological surgeries.METHODS: Forty patients were randomly allotted to receive either balanced general anaesthesia (n=20) or combined spinal epidural anaesthesia extending from T5 to S5 (n=20). Blood samples were collected for cortisol and glucose at preinduction, 1, 3 and 4 hours, and for insulin at preinduction and 24 hours after incision.RESULTS: The mean cortisol concentration was significantly lower 4 hours after incision with combined spinal epidural anaesthesia (19.96 ± 11.32) μg/dl than with balanced general anaesthesia (38.94 ± 10.6) μg/dl, p = 0.018. The mean insulin concentration, 24 hours after incision decreased with combined spinal epidural anaesthesia, but increased with balanced general anaesthesia p = 0.403. The mean glucose concentrations were significantly lower with combined spinal epidural anaesthesia than with balanced general anaesthesia during the 4 hour study period p ≤ 0.05.CONCLUSION: combined spinal epidural anaesthesia extending from T5 to S5 resulted in lower cortisol, insulin and glucose concentrations during major gynaecological surgeries. This may be of benefit in patients scheduled for surgical operations below the umbilicus.

Nutrition optimization prior to surgery

Optimization of metabolic state prior to major surgery leads to improved surgical outcomes. Nutrition screening protocols should be implemented in the preoperative evaluation, possibly as part of a bundle. Strategies to minimize hyperglycemia and insulin resistance by aggressive preoperative nutrition and carbohydrate loading may promote maintenance of a perioperative anabolic state, improving healing, reducing complications, and shortening the time to recovery of bowel function and hospital discharge. Short courses of preoperative immune-modulating formulas, using combinations of arginine, ω-3 fatty acids, and other nutrients, have been associated with improved surgical outcomes. These immune-modulating nutrients are key elements of metabolic pathways that promote attenuation of the metabolic response to stress and improve both wound healing and immune function. Patients with severe malnutrition and gastrointestinal dysfunction may benefit from preoperative parenteral nutrition. Continuation of feeding through the intraoperative period for severely stressed hypermetabolic patients undergoing nongastrointestinal surgery is another strategy to optimize metabolic state and reduce prolonged nutrition deficits. In this paper, we review the importance of preoperative nutrition and strategies for effective preoperative nutrition optimization.

Novel nutritional substrates in surgery

Pharmaco-nutrients have beneficial effects on protective and immunological mechanisms in patients undergoing surgery, which are important for recovery after injury and in combating infectious agents. The aim of this review article was to outline the potential of the administration of nutritional substrates to surgical patients and the underlying mechanisms that make them particularly important in peri-operative care. Surgery causes a stress response, which has catabolic effects on the body's substrate stores. The amino acid glutamine is a stimulating agent for immune cells. It activates protective mechanisms through its role as a precursor for antioxidants and it improves the barrier function of the gut. Arginine also enhances the function of the immune system, since it is the substrate for T-lymphocytes. Furthermore, n-3 PUFA stabilise surgery-induced hyper-inflammation. Taurine is another substrate that may counteract the negative effects of surgical injury on acid–base balance and osmotic balance. These pharmaco-nutrients rapidly become deficient under the influence of surgical stress. Supplementation of these nutrients in surgical patients may restore their protective and immune-enhancing actions and improve clinical outcome. Moreover, pre-operative fasting is still common practice in the Western world, although fasting has a negative effect on the patient's condition and the recovery after surgery. This may be counteracted by a simple intervention such as administering a carbohydrate-rich supplement just before surgery. In conclusion, there are various nutritional substrates that may be of great value in improving the condition of the surgical patient, which may be beneficial for post-operative recovery.

Anesthesia and perioperative management of colorectal surgical patients - A clinical review (Part 1)

Colorectal surgery is commonly performed for colorectal cancer and other pathology such as diverticular and inflammatory bowel disease. Despite significant advances, such as laparoscopic techniques and multidisciplinary recovery programs, morbidity and mortality remain high and vary among surgical centers. The use of scoring systems and assessment of functional capacity may help in identifying high-risk patients and predicting complications. An understanding of perioperative factors affecting colon blood flow and oxygenation, suppression of stress response, optimal fluid therapy, and multimodal pain management are essential. These fundamental principles are more important than any specific choice of anesthetic agents. Anesthesiologists can significantly contribute to enhance recovery and improve the quality of perioperative care.

The impact of glutamine dipeptide-supplemented parenteral nutrition on outcomes of surgical patients: a meta-analysis of randomized clinical trials

OBJECTIVE

To evaluate the impact of glutamine dipeptide-supplemented parenteral nutrition (GLN-PN) on clinical outcomes in surgical patients.

METHODS

MEDLINE, EMBASE, Web of Science, and the Cochrane Controlled Clinical Trials Register were searched to retrieve the eligible studies. The studies were included if they were randomized controlled trials that evaluated the effect of GLN-PN and standard PN on clinical outcomes of surgical patients. Clinical outcomes of interest were postoperative morbidity of infectious complication, mortality, length of hospital stay, and cost. Statistical analysis was conducted by RevMan 4.2 software from the Cochrane Collaboration.

RESULTS

Fourteen randomized controlled trials (RCTs) (N = 587) were included in this meta-analysis. The results showed that glutamine dipeptide significantly reduced the length of hospital stay by around 4 days in the form of alanyl-glutamine (weighted mean difference [WMD] = -3.84; 95% confidence interval [CI] -5.40, -2.28; z = 4.82; P < .001) and about 5 days in the form of glycyl-glutamine (WMD = -5.40; 95% CI -8.46, -2.33; z = 3.45; P < .001). The overall effect indicated a significant decrease in the infectious complication rates of surgical patients receiving GLN-PN (risk ratio = 0.69; 95% CI 0.50, 0.95; z = 2.26; P = .02).

CONCLUSION

GLN-PN was beneficial to postoperative patients by shortening the length of hospital stay and reducing the morbidity of postoperative infectious complications.