Preoperative insulin resistance and the impact of feeding on postoperative protein balance: a stable isotope study

OUP accepted manuscript

Background

Wearable devices have been proposed as a novel method for monitoring patients after surgery to track recovery, identify complications early, and improve surgical safety. Previous studies have used a heterogeneous range of devices, methods, and analyses. This review aimed to examine current methods and wearable devices used for monitoring after abdominal surgery and identify knowledge gaps requiring further investigation.

Methods

A scoping review was conducted given the heterogeneous nature of the evidence. MEDLINE, EMBASE, and Scopus databases were systematically searched. Studies of wearable devices for monitoring of adult patients within 30 days after abdominal surgery were eligible for inclusion.

Results

A total of 78 articles from 65 study cohorts, with 5153 patients were included. Thirty-one different wearable devices were used to measure vital signs, physiological measurements, or physical activity. The duration of postoperative wearable device use ranged from 15 h to 3 months after surgery. Studies mostly focused on physical activity metrics (71.8 per cent). Continuous vital sign measurement and physical activity tracking both showed promise for detecting postoperative complications earlier than usual care, but conclusions were limited by poor device precision, adherence, occurrence of false alarms, data transmission problems, and retrospective data analysis. Devices were generally well accepted by patients, with high levels of acceptance, comfort, and safety.

Conclusion

Wearable technology has not yet realized its potential to improve postoperative monitoring. Further work is needed to overcome technical limitations, improve precision, and reduce false alarms. Prospective assessment of efficacy, using an intention-to-treat approach should be the focus of further studies.

Postoperative insulin secretion is decreased in patients with preoperative insulin resistance

BACKGROUND

Postoperative hyperglycemia is associated with increased rate of surgical site infection, renal failure, and cardiovascular events. The study of insulin sensitivity state before surgery could help in treating postoperative hyperglycemia and preventing iatrogenic hypoglycemia. We studied the postoperative insulin secretion in patients who have a low insulin sensitivity (IR) before surgery compared to patients with normal preoperative insulin sensitivity (IS).

MATERIALS AND METHODS

Forty-two consecutive patients, undergoing abdominal surgery, underwent preoperative sequential hyperglycemic-euglycemic clamp (SHEC) in order to measure insulin secretion and to screen patients with low insulin sensitivity (IR) or with normal insulin sensitivity (IS). Patients had been randomized to receive either general anesthesia with epidural or PCA.

RESULTS

Postoperative insulin secretion in IR patients is decreased compared to IS (P = 0.059) and to IR before surgery regardless to the type of analgesia (P < 0.001). In the IS group, postoperative insulin secretion depends on type of analgesia. It is increased when using PCA and decreased when using epidural (P < 0.05). Blood glucose increased after surgery in both IS an IR (P < 0.001). Patients with preoperative insulin resistance had a higher glycemia before and after surgery (P < 0.001). Blood glucose levels were comparable between PCA and epidural patients (P = 0.450).

CONCLUSION

Insulin secretion is reduced in IR regardless the type of anesthesia. PCA increases insulin secretion, whereas epidural decreases it in patients with normal insulin sensitivity. These findings implicate that after surgery insulin administration is advisable in patients with preoperative insulin resistance while it should be given cautiously in those with normal preoperative insulin sensitivity.

Association of Elevated Pre-operative Hemoglobin A1c and Post-operative Complications in Non-diabetic Patients: A Systematic Review

IMPORTANCE

Pre-operative hyperglycemia is associated with post-operative adverse outcomes in diabetic and non-diabetic patients. Current pre-operative screening includes random plasma glucose, yet plasma glycated hemoglobin (HbA1c) is a better measure of long-term glycemic control. It is not clear whether pre-operative HbA1c can identify non-diabetic patients at risk of post-operative complications.

OBJECTIVE

The systematic review summarizes the evidence pertaining to the association of suboptimal pre-operative HbA1c on post-operative outcomes in adult surgical patients with no history of diabetes mellitus.

EVIDENCE REVIEW

A detailed search strategy was developed by a librarian to identify all the relevant studies to date from the major online databases.

FINDINGS

Six observational studies met all the eligibility criteria and were included in the review. Four studies reported a significant association between pre-operative HbA1c levels and post-operative complications in non-diabetic patients. Two studies reported increased post-operative infection rates, and two reported no difference. Of four studies assessing the length of stay, three did not observe any association with HbA1c level and only one study observed a significant impact. Only one study found higher mortality rates in patients with suboptimal HbA1c.

CONCLUSIONS AND RELEVANCE

Based on the limited available evidence, suboptimal pre-operative HbA1c levels in patients with no prior history of diabetes predict post-operative complications and represent a potentially modifiable risk factor.

Enhanced Recovery After Surgery in Laparoscopic Surgery

BACKGROUND

As part of an effort to maximize value in the perioperative setting, a paradigm shift is underway in the way that patients are cared for preoperatively, on the day of surgery, and postoperatively-a setting collectively known as the perioperative care. Enhanced Recovery After Surgery (ERAS^®) is an evidence-based, patient-centered team approach to delivering high-quality perioperative care to surgical patients.

METHODS

This review focuses on anesthesiologists, with their unique purview of perioperative setting, who are important drivers of change in the delivery of valuable perioperative care. ERAS care pathways begin in the preoperative setting by both preparing the patient for the psychological stress of surgery and optimizing the patient's medical and physiologic status so the body is ready for the physical demands of surgery.

RESULTS

Minimization of perioperative fasting is important to maintain volume status-decreasing reliance on intravenous fluid administration, and to reduce protein catabolism around the time of surgery. Intraoperative management in ERAS pathways relies on goal-directed fluid therapy and opioid-sparing multimodal analgesia. Postoperatively, early feeding and ambulation, as well as discontinuation of extraneous lines and catheters facilitate patients' functional recovery.

CONCLUSION

The laparoscopic approach to surgery, when possible, compliments ERAS techniques by reducing abdominal wall trauma and the resultant milieu of inflammatory, neurohumoral, and pain responses. Anesthesiologists driving change in the perioperative setting, in collaboration with surgeons and other disciplines, can improve value in healthcare and provide optimal outcomes that matter most to patients and healthcare providers alike.

High dose amino acid administration achieves an anabolic response in type 2 diabetic patients that is independent of glycaemic control: A randomized clinical trial

BACKGROUND & AIMS

Surgical stress provokes protein catabolism and hyperglycaemia that is enhanced in patients with type 2 diabetes (T2DM), and increases perioperative morbidity. This study hypothesized that perioperative administration of high dose intravenous (IV) amino acids (AA) will augment protein balance in T2DM patients receiving tight plasma glucose control via continuous IV insulin compared to standard plasma glucose control via subcutaneous (SC) insulin sliding scale.

METHODS

Eighteen patients with well-controlled T2DM (HbA1C% < 7.1) undergoing colorectal surgery were assigned randomly to receive standard glucose control (6-10 mmol/l, SC insulin, n = 9) or tight glucose control (4-6 mmol/l, IV insulin, n = 9). Both groups received general anaesthesia and epidural analgesia. AA (1 ml/kg h Aminoven™ 10%, ∼2.4 g/kg d) were infused via a peripheral vein for two 3-h periods: at the beginning of surgery and in the post-operative care unit. Whole-body protein and glucose kinetics were assessed by stable isotope tracers, L-[1-¹³C]leucine and [6,6-²H₂]glucose.

RESULTS

Whole-body protein balance was positive after surgery in all patients. Since protein synthesis, breakdown and leucine oxidation were comparable in both groups, whole body protein balance was not different (p = 0.605). Tight glucose control suppressed endogenous glucose production (EGP, p < 0.001) and increased glucose clearance (p < 0.001) compared to standard glucose control during both study periods. No episode of hypoglycaemia occurred in either group.

CONCLUSION

High-dose perioperative AA administration under optimal anti-catabolic care with epidural analgesia was effective in achieving a positive protein balance in T2DM patients undergoing surgery that was independent of glycaemic control strategy. Continuous IV insulin maintained normoglycaemia by inhibiting EGP and increasing glucose clearance. Improved glucose control, without a pronounced increase in protein balance with the intravenous insulin regimen, suggests perioperative protein metabolism may be less sensitive to insulin than is glucose.

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.

Twenty-four hour hyperinsulinemic-euglycemic clamp improves postoperative nitrogen balance only in low insulin sensitivity patients following cardiac surgery

BACKGROUND

Critically ill patients often suffer from a protein catabolic state. The aim of this study was to demonstrate that nitrogen balance (NB) in cardiac patients admitted to the intensive care unit (ICU) is related to their insulin sensitivity level and that supraphysiologic doses of insulin can restore anabolism.

MATERIALS AND METHODS

Twenty-eight patients that were admitted to ICU in enteral and/or parenteral nutrition have been enrolled in this study. All patients received a standard nutrition protocol for at least 3 days before starting the study. These patients received either enteral or parenteral nutrition based on 1.4 kcal/kg/h and 1.1 g/kg/24 h of proteins. Participants were studied for three 24 h periods (P1 , P2 , and P3 ). Twenty-four hour NB was calculated from urinary urea nitrogen excretion, fixed protein and energy intake during each of the three periods (P1 , P2 , and P3 ). Simultaneous to P2, a 24 h hyperinsulinemic-euglycemic clamp (HEC) was performed to determine patients' insulin sensitivity (IS) or insulin resistance (IR), as well as the impact of high doses of insulin on NB.

RESULTS

Nitrogen balance remained consistently positive in the IS group regardless of the clamp. In IR patients, NB was negative before the clamp and became positive during P2 and P3 . Insulin sensitivity improved during the HEC in IR patients (P < 0.001).

CONCLUSIONS

A negative NB was found only in insulin resistant patients admitted to the ICU for more than 7 days. A 24-h period HEC improved NB in these patients.

Physiologic considerations of Enhanced Recovery After Surgery (ERAS) programs: implications of the stress response

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.

Effects of preoperative oral carbohydrate supplementation on postoperative metabolic stress response of patients undergoing elective abdominal surgery

BACKGROUND

The goal of the present study was to evaluate the effects of preoperative oral carbohydrate supplementation (OCH) on the postoperative metabolic stress response of patients undergoing elective abdominal surgery.

METHODS

The study was designed as a controlled, prospective, cohort study including 38 patients treated with OCH (800 mL the day before surgery and 400 mL within 3 h before the induction of anesthesia) and 38 controls matched for surgical procedure. Fasting glucose, insulin, insulin resistance (HOMA-IR index), cortisol, and interleukin 6 (IL-6) were assessed before and after surgery (postoperative day (POD) 1, 2, and 3).

RESULTS

The administration of OCH resulted in lower fasting glucose, HOMA-IR index, cortisol, and IL-6 on both POD 1 and POD 2. At multivariable regression analyses, the reduction of these parameters was independent of sex, age, body mass index, and major abdominal surgery. Particularly, models including OCH treatment explained 70, 63, and 66 % of the variance of the increase in IL-6 levels at POD 1, POD 2, and POD 3, respectively. The effect of OCH on changes in glucose, insulin resistance, and cortisol on POD 1 and POD 2 disappeared after the inclusion of IL-6 in the models.

CONCLUSIONS

Treatment with OCH was associated with attenuation of the postoperative metabolic stress response. We hypothesize that modulation of the inflammatory response is one of the mechanisms involved.