Epidural blockade improves substrate utilization after surgery

Efficacy of different analgesia treatments for abdominal surgery: A network meta-analysis

OBJECTIVE

This study was designed to evaluate the efficacy of analgesia and incidence of postoperative nausea and vomiting (PONV) of several widely used clinical treatments for postoperative analgesia following abdominal surgery through network meta-analysis (NMA) based on published randomized controlled trials (RCTs).

METHODS

This NMA was registered on PROSPERO as CRD 42020169606. Primary outcomes were pain scores (visual analog scale) and accumulative opioid consumption, and secondary outcomes assessed the incidence of PONV at 24 h after surgery.

RESULTS

A total of 215 RCTs and 15,114 patients were identified in this NMA. In comparison with placebo, use of a preoperative paravertebral block (mean: -12.63, 95% CI: -21.12 to -4.13), continuous wound infiltration (mean: -9.68, 95%CI: -13.15 to -6.22) and postoperative wound infiltration (mean: -6.34, 95%CI: -10.59 to -2.08) had significantly lower pain scores, less opioid consumption (mean: -2.00, 95%CI: -3.52 to -0.48; mean: -1.34, 95%CI: -1.87 to -0.81; mean: -1.41, 95%CI: -2.07 to -0.74, respectively) and lower incidence of PONV (OR: 0.30, 95%CI: 0.13 to 0.67; OR: 0.49, 95%CI: 0.24 to 0.98; OR: 0.55, 95%CI: 0.34 to 0.89, respectively).

CONCLUSIONS

The findings from our work provide evidence that preoperative paravertebral block was superior to continuous or postoperative wound infiltration to provide postoperative analgesia, nausea and vomiting after abdominal surgery.

Could Exogenous Insulin Ameliorate the Metabolic Dysfunction Induced by Glucocorticoids and COVID-19?

The finding that high-dose dexamethasone improves survival in those requiring critical care due to COVID-19 will mean much greater usage of glucocorticoids in the subsequent waves of coronavirus infection. Furthermore, the consistent finding of adverse outcomes from COVID-19 in individuals with obesity, hypertension and diabetes has focussed attention on the metabolic dysfunction that may arise with critical illness. The SARS coronavirus itself may promote relative insulin deficiency, ketogenesis and hyperglycaemia in susceptible individuals. In conjunction with prolonged critical care, these components will promote a catabolic state. Insulin infusion is the mainstay of therapy for treatment of hyperglycaemia in acute illness but what is the effect of insulin on the admixture of glucocorticoids and COVID-19? This article reviews the evidence for the effect of insulin on clinical outcomes and intermediary metabolism in critical illness.

The effect of glucose control in liver surgery on glucose kinetics and insulin resistance

BACKGROUND & AIMS

Clinical outcome is negatively correlated to postoperative insulin resistance and hyperglycemia. The magnitude of insulin resistance can be modulated by glucose control, preoperative nutrition, adequate pain management and minimal invasive surgery. Effects of glucose control on perioperative glucose kinetics in liver surgery is less studied.

METHODS

18 patients scheduled for open hepatectomy were studied per protocol in this prospective, randomized study. In the treatment group (n = 9), insulin was administered intravenously to keep arterial blood glucose between 6 and 8 mmol/l during surgery. The control group (n = 9) received insulin if blood glucose >11.5 mmol/l. Insulin sensitivity was measured by an insulin clamp on the day before surgery and immediately postoperatively. Glucose kinetics were assessed during the clamp and surgery.

RESULTS

Mean intraoperative glucose was 7.0 mM (SD 0.7) vs 9.1 mM (SD 1.9) in the insulin and control group respectively (p < 0.001; ANOVA). Insulin sensitivity decreased in both groups but significantly (p = 0.03, ANOVA) more in the control group (M value: 4.6 (4.4-6.8) to 2.1 (1.2-2.6) and 4.6 (4.1-5.0) to 0.6 (0.1-1.8) mg/kg/min in the treatment and control group respectively). Endogenous glucose production (EGP) increased and glucose disposal (WGD) decreased significantly between the pre- and post-operative clamps in both groups, with no significant difference between the groups. Intraoperative kinetics demonstrated that glucose control decreased EGP (p = 0.02) while WGD remained unchanged (p = 0.67).

CONCLUSION

Glucose control reduces postoperative insulin resistance in liver surgery. EGP increases and WGD is diminished immediately postoperatively. Insulin seems to modulate both reactions, but mostly the WGD is affected. Intraoperative EGP decreased while WGD remained unaltered.

REGISTRATION NUMBER OF CLINICAL TRIAL

ANZCTR 12614000278639.

Epidural analgesia versus patient-controlled intravenous analgesia for pain following intra-abdominal surgery in adults

BACKGROUND

Intravenous patient-controlled analgesia (IVPCA) with opioids and epidural analgesia (EA) using either continuous epidural administration (CEA) or patient-controlled (PCEA) techniques are popular approaches for analgesia following intra-abdominal surgery. Despite several attempts to compare the risks and benefits, the optimal form of analgesia for these procedures remains the subject of debate.

OBJECTIVES

The objective of this review was to update and expand a previously published Cochrane Review on IVPCA versus CEA for pain after intra-abdominal surgery with the addition of the comparator PCEA. We have compared both forms of EA to IVPCA. Where appropriate we have performed subgroup analysis for CEA versus PCEA.

SEARCH METHODS

We searched the following electronic databases for relevant studies: Cochrane Central Register of Controlled Trials (CENTRAL) (2017; Issue 8), MEDLINE (OvidSP) (1966 to September 2017), and Embase (OvidSP) (1988 to September 2017) using a combination of MeSH and text words. We searched the following trial registries: Australian New Zealand Clinical Trials Registry, ClinicalTrials.gov, and the EU Clinical Trials Register in September 2017, together with reference checking and citation searching to identify additional studies.We included only randomized controlled trials and used no language restrictions.

SELECTION CRITERIA

We included all parallel and cross-over randomized controlled trials (RCTs) comparing CEA or PCEA (or both) with IVPCA for postoperative pain relief in adults following intra-abdominal surgery.

DATA COLLECTION AND ANALYSIS

Two review authors (JS and EY) independently identified studies for eligibility and performed data extraction using a data extraction form. In cases of disagreement (three occasions) a third review author (MB) was consulted. We appraised each included study to assess the risk of bias as outlined in Section 8.5 of the Cochrane Handbook for Systematic Reviews of Interventions. We used GRADE to assess the quality of the evidence.

MAIN RESULTS

We included 32 studies (1716 participants) in our review. There are 10 studies awaiting classification and one ongoing study. A total of 869 participants (51%) received EA and 847 (49%) received IVPCA. The EA trials included 16 trials with CEA (418 participants) and 16 trials with PCEA (451 participants). The studies included a broad range of surgical procedures (including hysterectomies, radical prostatectomies, Caesarean sections, colorectal and upper gastrointestinal procedures), a wide range of adult ages, and were performed in several different countries.Our pooled analyses suggested a benefit with regard to pain scores (using a visual analogue scale between 0 and 100) in favour of EA techniques at rest. The mean pain reduction at rest from waking to six hours after operation was 5.7 points (95% confidence interval (CI) 1.9 to 9.5; 7 trials, 384 participants; moderate-quality evidence). From seven to 24 hours, the mean pain reduction was 9.0 points (95% CI 4.6 to 13.4; 11 trials, 558 participants; moderate-quality evidence). From 24 hours the mean pain reduction was 5.1 points (95% CI 0.9 to 9.4; 7 trials, 393 participants; moderate-quality evidence). Due to high statistical heterogeneity, no pooled analysis was possible for the estimation of pain on movement at any time. Two single studies (one using CEA and one PCEA) reported lower pain scores with EA compared to IVPCA at 0 to 6 hours and 7 to 24 hours. At > 24 hours the results from 2 studies (both CEA) were conflicting.We found no difference in mortality between EA and IVPCA, although the only deaths reported were in the EA group (5/287, 1.7%). The risk ratio (RR) of death with EA compared to using IVPCA was 3.37 (95% CI 0.72 to 15.88; 9 trials, 560 participants; low-quality evidence).A single study suggested that the use of EA may result in fewer episodes of respiratory depression, with an RR of 0.47 (95% CI 0.04 to 5.69; 1 trial; low-quality evidence). The successful placement of an epidural catheter can be technically challenging. The improvements in pain scores above were accompanied by an increase in the risk of failure of the analgesic technique with EA (RR 2.48, 95% CI 1.13 to 5.45; 10 trials, 678 participants; moderate-quality evidence); the occurrence of pruritus (RR 2.36, 95% CI 1.67 to 3.35; 8 trials, 492 participants; moderate-quality evidence); and episodes of hypotension requiring intervention (RR 7.13, 95% CI 2.87 to 17.75; 6 trials, 479 participants; moderate-quality evidence). There was no clear evidence of an advantage of one technique over another for other adverse effects considered in this review (Venous thromboembolism with EA (RR 0.32, 95% CI 0.03 to 2.95; 2 trials, 101 participants; low-quality evidence); nausea and vomiting (RR 0.94, 95% CI 0.69 to 1.27; 10 trials, 645 participants; moderate-quality evidence); sedation requiring intervention (RR 0.87, 95% CI 0.40 to 1.87; 4 trials, 223 participants; moderate-quality evidence); or episodes of desaturation to less than 90% (RR 1.29, 95% CI 0.71 to 2.37; 5 trials, 328 participants; moderate-quality evidence)).

AUTHORS' CONCLUSIONS

The additional pain reduction at rest associated with the use of EA rather than IVPCA is modest and unlikely to be clinically important. Single-trial estimates provide low-quality evidence that there may be an additional reduction in pain on movement, which is clinically important. Any improvement needs to be interpreted with the understanding that the use of EA is also associated with an increased chance of failure to successfully institute analgesia, and an increased likelihood of episodes of hypotension requiring intervention and pruritus. We have rated the evidence as of moderate quality given study limitations in most of the contributing studies. Further large RCTs are required to determine the ideal analgesic technique. The 10 studies awaiting classification may alter the conclusions of the review once assessed.

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.

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.

Epidural local anaesthetics versus opioid-based analgesic regimens for postoperative gastrointestinal paralysis, vomiting and pain after abdominal surgery

BACKGROUND

Gastrointestinal paralysis, nausea and vomiting and pain are major clinical problems following abdominal surgery. Anaesthetic and analgesic techniques that reduce pain and postoperative nausea and vomiting (PONV), while preventing or reducing postoperative ileus, may reduce postoperative morbidity, duration of hospitalization and hospital costs. This review was first published in 2001 and was updated by new review authors in 2016.

OBJECTIVES

To compare effects of postoperative epidural analgesia with local anaesthetics versus postoperative systemic or epidural opioids in terms of return of gastrointestinal transit, postoperative pain control, postoperative vomiting, incidence of anastomotic leak, length of hospital stay and costs after abdominal surgery.

SEARCH METHODS

We identified trials by conducting computerized searches of the Cochrane Central Register of Controlled Trials (CENTRAL) (2014, Issue 12), MEDLINE (from 1950 to December 2014) and EMBASE (from 1974 to December 2014) and by checking the reference lists of trials retained. When we reran the search in February 2016, we added 16 potential new studies of interest to the list of 'Studies awaiting classification' and will incorporate these studies into formal review findings during the next review update.

SELECTION CRITERIA

We included parallel randomized controlled trials comparing effects of postoperative epidural local anaesthetic versus regimens based on systemic or epidural opioids.

DATA COLLECTION AND ANALYSIS

We rated the quality of studies by using the Cochrane 'Risk of bias' tool. Two review authors independently extracted data and judged the quality of evidence according to the GRADE (Grades of Recommendation, Assessment, Development and Evaluation Working Group) scale.

MAIN RESULTS

We included 128 trials with 8754 participants in the review, and 94 trials with 5846 participants in the analysis. Trials included in the review were funded as follows: charity (n = 19), departmental resources (n = 8), governmental sources (n = 15) and industry (in part or in total) (n = 15). The source of funding was not specified for the other studies.Results of 22 trials including 1138 participants show that an epidural containing a local anaesthetic will decrease the time required for return of gastrointestinal transit as measured by time to first flatus after an abdominal surgery (standardized mean difference (SMD) -1.28, 95% confidence interval (CI) -1.71 to -0.86; high quality of evidence; equivalent to 17.5 hours). The effect is proportionate to the concentration of local anaesthetic used. A total of 28 trials including 1559 participants reported a decrease in time to first faeces (stool) (SMD -0.67, 95% CI -0.86 to -0.47; low quality of evidence; equivalent to 22 hours). Thirty-five trials including 2731 participants found that pain on movement at 24 hours after surgery was also reduced (SMD -0.89, 95% CI -1.08 to -0.70; moderate quality of evidence; equivalent to 2.5 on scale from 0 to 10). From findings of 22 trials including 1154 participants we did not find a difference in the incidence of vomiting within 24 hours (risk ratio (RR) 0.84, 95% CI 0.57 to 1.23; low quality of evidence). From investigators in 17 trials including 848 participants we did not find a difference in the incidence of gastrointestinal anastomotic leak (RR 0.74, 95% CI 0.41 to 1.32; low quality of evidence). Researchers in 30 trials including 2598 participants noted that epidural analgesia reduced length of hospital stay for an open surgery (SMD -0.20, 95% CI -0.35 to -0.04; very low quality of evidence; equivalent to one day). Data on costs were very limited.

AUTHORS' CONCLUSIONS

An epidural containing a local anaesthetic, with or without the addition of an opioid, accelerates the return of gastrointestinal transit (high quality of evidence). An epidural containing a local anaesthetic with an opioid decreases pain after abdominal surgery (moderate quality of evidence). We did not find a difference in the incidence of vomiting or anastomotic leak (low quality of evidence). For open surgery, an epidural containing a local anaesthetic would reduce the length of hospital stay (very low quality of evidence).

Promoting Perioperative Metabolic and Nutritional Care

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.

Perioperative catabolism

PURPOSE

This article reviews the pathophysiology, clinical relevance, and therapy of the catabolic response to surgical stress.

PRINCIPLE FINDINGS

The key clinical features of perioperative catabolism are hyperglycemia and loss of body protein, both metabolic consequences of impaired insulin function. Muscle weakness and (even moderate) increases in perioperative blood glucose are associated with morbidity after major surgery. Although the optimal glucose concentration for improving clinical outcomes is unknown, most medical associations recommend treatment of random blood glucose > 10 mmol·L(-1). Neuraxial anesthesia blunts the neuroendocrine stress response and enhances the anabolic effects of nutrition. There is evidence to suggest that the avoidance of preoperative fasting prevents insulin resistance and accelerates recovery after major abdominal surgery.

CONCLUSIONS

Current anticatabolic therapeutic strategies include glycemic control and perioperative nutrition in combination with optimal pain control and the avoidance of preoperative starvation. All these elements are part of Enhanced Recovery After Surgery (ERAS) programs.

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.

Glucose and insulin administration while maintaining normoglycemia inhibits whole body protein breakdown and synthesis after cardiac surgery

We investigated the effect of insulin administered as part of a hyperinsulinemic-normoglycemic clamp on protein metabolism after coronary artery bypass grafting (CABG) surgery. Eighteen patients were studied, with nine patients in the control group receiving standard metabolic care and nine patients receiving insulin (5 mU·kg(-1)·min(-1)). Whole body glucose production, protein breakdown, synthesis, and oxidation were determined using stable isotope tracer kinetics (l-[1-(13)C]leucine, [6,6-(2)H2]glucose) before and 6 h after the procedure. Plasma amino acids, cortisol, and lactate were also measured. Endogenous glucose production (preoperatively 10.0 ± 1.6, postoperatively 3.7 ± 2.5 μmol·kg(-1)·min(-1); P = 0.0001), protein breakdown (preoperatively 105.3 ± 9.8, postoperatively 85.2 ± 9.2 mmol·kg(-1)·h(-1); P = 0.0005) and synthesis (preoperatively 88.7 ± 8.7, postoperatively 72.4 ± 8.4 mmol·kg(-1)·h(-1); P = 0.0005) decreased in the presence of hyperinsulinemia, whereas both parameters remained unchanged in the control group. A positive correlation between endogenous glucose production and protein breakdown was observed in the insulin group (r(2) = 0.385). Whole body protein oxidation and balance decreased after surgery in patients receiving insulin without reaching statistical significance. In the insulin group the plasma concentrations of 13 of 20 essential and nonessential amino acids decreased to a significantly greater extent than in the control group. In summary, supraphysiological hyperinsulinemia, while maintaining normoglycemia, decreased whole body protein breakdown and synthesis in patients undergoing CABG surgery. However, net protein balance remained negative.

The anabolic effect of perioperative nutrition depends on the patient's catabolic state before surgery

OBJECTIVE

We tested the hypothesis that the anabolic effect of hypocaloric, isonitrogenous nutrition in patients undergoing colorectal surgery depends on the patient's preoperative catabolic state.

BACKGROUND

Although there is evidence to suggest that total parenteral nutrition more effectively spares protein in depleted than in nondepleted cancer patients, the influence of preoperative catabolism on the anabolic effects of hypocaloric nutrition in patients undergoing elective surgery is unknown.

METHODS

Seventeen patients undergoing colorectal surgery received intravenous infusion of glucose with amino acids. Feeding was administered over 72 hours, from 24 hours before until 48 hours after surgery. Glucose provided 50% of the patient's measured resting energy expenditure. Amino acids provided 20% of the resting energy expenditure. Whole-body leucine balance (difference between the incorporation of leucine into protein = protein synthesis and endogenous leucine release = proteolysis) was determined using L-[1-(13)C]leucine kinetics before and 2 days after surgery. We analyzed the association between the postoperative increase in leucine balance and the following factors: preoperative leucine balance, protein breakdown, weight loss, oxygen consumption, circulating concentrations of glucose, free fatty acids, insulin, glucagon, cortisol, albumin, age, duration of surgery, and blood loss.

RESULTS

Of 6 potentially relevant variables, 4 (weight loss, protein breakdown, albumin, and cortisol) were removed because they were not significant during the stepwise linear regression procedure. Leucine balance and age were the remaining 2 factors that remained with the final regression model: Δleucine balance = 19.1 - (0.20 × age [years]) - (0.58) × leucine balance(preOP)).

CONCLUSIONS

We demonstrate a significant association between the degree of preoperative catabolism, the patient's age, and the anabolic effect of hypocaloric nutrition (ClinicalTrials.gov registration ID: NCT01414946).

Influence of patient-controlled epidural analgesia versus patient-controlled intravenous analgesia on postoperative pain control and recovery after gastrectomy for gastric cancer: a prospective randomized trial

BACKGROUND

Patient-controlled epidural analgesia (PCEA) has not been widely used after gastrectomy, although, in other abdominal surgery, it benefits patients more than patient-controlled intravenous analgesia (PCIA). We attempted to determine the effect of PCEA compared with PCIA on postoperative pain control and recovery after gastrectomy for gastric cancer.

METHODS

A randomized controlled clinical trial that included patients undergoing D2 radical gastrectomy for gastric cancer was conducted for this study. Patients were randomized to a morphine-bupivacaine PCEA group and a morphine PCIA group. Postoperative outcomes such as pain, fasting blood glucose (FBG), time to first passage of flatus, complications, and time staying in hospital after surgery were compared with an intention-to-treat analysis.

RESULTS

Between March 2010 and October 2010, 67 patients were randomized and 60 were evaluated. The PCEA group showed lower pain scores both at rest and on coughing after the operation (P < 0.05). FBG after the operation was significantly lower in the PCEA group than that in the PCIA group (P < 0.05). Time to first passage of flatus after surgery was shorter in the PCEA group (P < 0.05), while there were no significant differences regarding the incidence of complications between the two groups in terms of the clinical records. The length of hospital stay in the PCEA group was 10.7 ± 1.7 days, which was significantly shorter than that in the PCIA group (11.9 ± 1.8 days, P < 0.05).

CONCLUSIONS

After gastrectomy for gastric cancer, PCEA, compared with PCIA, offered safer pain relief with superior pain control and resulted in a lower stress response and a quicker return of bowel activity.

Parenteral amino acids v. dextrose infusion: an anabolic strategy to minimise the catabolic response to surgery while maintaining normoglycaemia in diabetes mellitus type 2 patients

Loss of body protein and hyperglycaemia represent typical features of the stress response to surgery and anaesthesia. This appears to be particularly pronounced in patients with diabetes mellitus type 2. The aim of the present study was to highlight the greater benefit of amino acids (AA) as represented by positive protein balance and maintenance of blood glucose homoeostasis compared with dextrose (DEX) in diabetic patients after colorectal surgery. A total of thirteen patients underwent a 5 h stable isotope infusion study (2 h fasted, 3 h fed with an infusion of AA (n 6) or DEX (n 7)) on the second post-operative day. Glucose and protein kinetics were assessed by using the stable isotopes l-[1-13C]leucine and [6,6-2H2]glucose. The transition from fasted to fed state decreased endogenous glucose production (P < 0·001) in both groups, with a more profound effect in the DEX group (P = 0·031). In contrast, total glucose production was increased by the provision of DEX while being lowered by AA (P = 0·021). Feeding decreased protein oxidation (P = 0·009) and protein synthesis in the AA group, whereas DEX infusion did not affect oxidation and even decreased protein synthesis. Therefore, only AA shifted protein balance to a positive value, while patients in the DEX group remained in a catabolic state (P < 0·001). Parenteral nutritional support with AA rather than with DEX is an effective strategy to achieve a positive protein balance while maintaining normoglycaemia in diabetic patients after colorectal surgery.

Glucose and protein kinetics in patients undergoing colorectal surgery: perioperative amino acid versus hypocaloric dextrose infusion

Surgical injury provokes a stress response that leads to a catabolic state and, when prolonged, interferes with the postoperative recovery process. This study tests the impact of 2 nutrition support regimens on protein and glucose metabolism as part of an integrated approach in the perioperative period incorporating epidural analgesia in 18 nondiabetic patients undergoing colorectal surgery. To test the hypothesis that parenteral amino acid infusion (amino acid group, n = 9) maintains glucose homeostasis while maintaining normoglycemia and reduces proteolysis compared with infusion of dextrose alone (DEX group, n = 9), glucose and protein kinetics were measured before and on the second day after surgery using a stable isotope tracer technique. Postoperatively, the rate of appearance of glucose was higher (P < .001) and blood glucose increased more (P < .001) in the DEX group than in the amino acid group. The postoperative increase in the appearance of leucine from protein breakdown tended to be greater (P = .077) in the DEX group. We conclude that perioperative infusion of a nutrition support regimen delivering amino acids alone maintains blood glucose homeostasis and normoglycemia and tends to have a suppressive effect on protein breakdown compared with infusion of dextrose alone.

Protein balance in nondiabetic versus diabetic patients undergoing colon surgery: effect of epidural analgesia and amino acids

BACKGROUND

Surgical injury provokes a stress response that is thought to be pronounced in patients with diabetes mellitus type 2 (DM2) leading to intensified catabolism. The aim of this study was to compare the effects of perioperative epidural analgesia (EDA) versus patient controlled analgesia (PCA) and amino acid infusion on postoperative metabolism in patients with and without DM2.

METHODS

For this study, 12 nondiabetic patients and 12 diabetic patients undergoing colorectal surgery were randomly assigned to 4 groups (n = 6 per group) receiving either EDA (nondiabetic EDA and diabetic EDA [DEDA group]) or PCA with morphine (nondiabetic PCA and diabetic PCA) for perioperative pain control. Protein and glucose kinetics were measured on the second postoperative day using L-[1-13C]leucine and [6,6-2H2]glucose infusion during a fasted state and a 3-hr fed state with amino acid infusion.

RESULTS

The transition from the fasted to fed state suppressed endogenous rate of appearance (Ra) of glucose (P G 0.001) with a distinct effect for the DEDA group (P G 0.001). The Ra of leucine and the endogenous rate of appearance of leucine tended to be lower in the DEDA group(P = 0.056 and P = 0.07). Leucine oxidation was more suppressed in the DEDA group (P = 0.02) and when receiving amino acids(P = 0.001). Diabetic patients achieved a higher protein balance than nondiabetic patients (P = 0.032) and when receiving EDA instead of PCA (P = 0.012) or infusion of amino acids (P = 0.014).

CONCLUSIONS

A short-term infusion of amino acids reduced protein breakdown, increased protein synthesis, and rendered protein balance positive. This anabolic effect was pronounced in diabetic patients with EDA compared with nondiabetic patients or PCA, respectively, and prevented an undesirable hyperglycemia.

Increased energy expenditure and glucose oxidation during acute nontraumatic skin pain in humans

BACKGROUND AND OBJECTIVE

Tissue injury is accompanied by pain and results in increased energy expenditure, which may promote catabolism. The extent to which pain contributes to this sequence of events is not known.

METHODS

In a cross-over design, 10 healthy volunteers were examined on three occasions; first, during self-controlled nontraumatic electrical painful stimulus to the abdominal skin, maintaining an intensity of 8 on the visual analogue scale (0-10). Next, the electrical stimulus was reproduced during local analgesia and, finally, there was a control session without stimulus. Indirect calorimetry and blood and urine sampling was done in order to calculate energy expenditure and substrate utilization.

RESULTS

During pain stimulus, energy expenditure increased acutely and reversibly by 62% (95% confidence interval, 43-83), which was abolished by local analgesia. Energy expenditure paralleled both heart rate and blood catecholamine levels. The energy expenditure increase was fuelled by all energy sources, with the largest increase in glucose utilization.

CONCLUSION

The pain-related increase in energy expenditure was possibly mediated by adrenergic activity and was probably to a large extent due to increased muscle tone. These effects may be enhanced by cortical events related to the pain. The increase in glucose consumption favours catabolism. Our findings emphasize the clinical importance of pain management.

Randomized clinical trial of the effect of preoperative oral carbohydrate treatment on postoperative whole-body protein and glucose kinetics

Background

Preoperative oral carbohydrate (CHO) reduces postoperative insulin resistance. In this randomized trial, the effect of CHO on postoperative whole-body protein turnover was studied.

Methods

Glucose and protein kinetics ([6,62H2]D-glucose, [2H5]phenylalanine, [2H2]tyrosine and [2H4]tyrosine) and substrate oxidation (indirect calorimetry) were studied at baseline and during hyperinsulinaemic normoglycaemic clamping before and on the first day after colorectal resection. Fifteen patients were randomized to receive a preoperative beverage with high (125 mg/ml) or low (25 mg/ml) CHO content.

Results

Three patients were excluded after the intervention, leaving six patients in each group. After surgery whole-body protein balance did not change in the high oral CHO group, whereas it was more negative in the low oral CHO group after surgery at baseline (P = 0·003) and during insulin stimulation (P = 0·005). Insulin-stimulated endogenous glucose release was similar before and after surgery in the high oral CHO group, but was higher after surgery in the low oral CHO group (P = 0·013) and compared with the high oral CHO group (P = 0·044).

Conclusion

Whole-body protein balance and the suppressive effect of insulin on endogenous glucose release are better maintained when patients receive a CHO-rich beverage before surgery.

The effect of epidural analgesia on postoperative outcome after colorectal surgery

OBJECTIVE

The aim of this review was to determine the effects of epidural analgesia as it relates to outcome after colorectal surgery.

METHOD

We searched and reviewed studies that included colorectal surgery and epidural method of analgesia listed on the Pubmed, Medline, Embase and the Cochrane library database.

RESULTS

The majority of data demonstrate a superior effect of epidural analgesia on pain control after colorectal surgery. Well designed randomized controlled trials (RCT's) have also shown that epidural analgesia reduces the duration of ileus after colorectal surgery. Limited data suggest the additional benefit may be minimal after laparoscopic surgery or when epidural analgesia is used as part of a multimodal regime. Data does not convincingly show either a clear harmful or beneficial effect of epidural analgesia on rates of anastomotic leakage. Epidural analgesia may have beneficial effects on postoperative lung function, however due to low numbers, the effects on cardiovascular and thromboembolic complications are indeterminate. Length of hospital stay has not been shown to be shortened by sole use of an epidural and, although epidural analgesia may be apparently more costly, alternatives may incur higher indirect costs and decreased patient satisfaction.

CONCLUSION

Randomized controlled trials have shown a benefit for epidurals on postoperative pain relief, and ileus, and possibly respiratory complications. There is no proven benefit with regard to length of stay. There are a number of unresolved issues which further focussed RCT's may help clarify such as effects of epidural on complication rates after colorectal surgery.

Epidural Anesthesia and Analgesia Decrease the Postoperative Incidence of Insulin Resistance in Preoperative Insulin-Resistant Subjects Only

BACKGROUND

Insulin resistance (IR) is a feature of the endocrine stress response to surgery. It is not known whether a preoperative state of IR would affect the postoperative endocrine response. We sought to characterize the preoperative state of IR in a group of patients undergoing elective hip and knee arthroplasty, and to determine to what extent perioperative epidural analgesia modifies the postoperative state of IR in those who are and are not insulin-resistant before surgery.

METHODS

Sixty patients undergoing either hip or knee arthroplasty were screened by using the homeostatic model assessment (HOMA) in two populations: insulin-resistant patients and noninsulin-resistant patients, whereas HOMA is fasting insulin (microU/mL) x fasting glucose (mmol/L)/22.5. The patients belonging to each population were then randomly assigned to receive either intraoperative epidural blockade followed by postoperative epidural analgesia (epidural group) or general anesthesia followed by patient-controlled analgesia (control group). Analgesia was assessed with visual analog scale up to 48 h after surgery and HOMA was repeated at the end of surgery and 48 h after surgery to determine the postoperative state of IR.

RESULTS

Epidural anesthesia and analgesia significantly influenced the postoperative HOMA score (smaller proportion of IR) in the postoperative period only in those patients who were insulin-resistant before surgery (P < 0.01). In contrast, noninsulin-resistant patients had a similar postoperative proportion of IR between the epidural and control groups (P > 0.05). At rest and during movement, visual analog scale scores were not different between groups at the end of surgery and in the first and second days after surgery.

CONCLUSIONS

Epidural anesthesia and analgesia compared to general anesthesia followed by patient-controlled analgesia decreased the incidence of IR soon after surgery and 48 h after surgery only in patients who were insulin-resistant before surgery.

Intraoperative Infusion of Amino Acids Induces Anabolism Independent of the Type of Anesthesia

BACKGROUND

The infusion of dextrose in patients receiving epidural and light general anesthesia or general anesthesia alone failed to achieve a positive protein balance. We sought to verify the hypothesis that nutritional supplementation with i.v. amino acids induced a greater protein balance in patients receiving epidural blockade compared with those receiving general anesthesia.

METHODS

Sixteen patients were randomly assigned to receive either general anesthesia with desflurane (control group) or general anesthesia combined with epidural analgesia (EDA group). A primed constant infusion of stable isotope tracers L-[1-(13)C]leucine and [6,6-(2)H2]glucose was started after a 32-h fast before surgery, (3 h of fasted state), and continued for 3 h during surgery during which amino acids were infused i.v. (fed state).

RESULTS

Compared with the fasted state, the endogenous rate of appearance of leucine decreased to a similar extent in both groups, and protein synthesis increased, with no difference between the two groups. Leucine oxidation did not change in either group. After amino acids infusion, endogenous glucose production remained unchanged and glucose clearance decreased in both groups. Blood glucose, plasma cortisol, serum insulin, and glucagon concentrations increased to the same extent in both groups.

CONCLUSIONS

Epidural anesthesia provided no additional benefit beyond the anabolism obtained with amino acids.

Randomized clinical trial of the anabolic effect of hypocaloric parenteral nutrition after abdominal surgery

BACKGROUND

The observed failure of hypocaloric nutrition to establish an anabolic state after surgery may reflect inadequate control for the type and quality of analgesia in the studies performed. This study was designed to test the hypothesis that hypocaloric nutrition induces anabolism in patients who receive effective segmental pain relief using perioperative epidural analgesia.

METHODS

Sixteen patients who underwent colorectal surgery and received epidural analgesia were randomly assigned to receive intravenous glucose either without (glucose only) or with amino acids (nutrition). Feeding was administered over 48 h from surgical skin incision until the second day after operation. Glucose provided 50 per cent of the patient's resting energy expenditure (REE). Amino acids were infused at rates that provided 20 per cent of REE. Leucine rate of appearance (Ra), leucine oxidation and non-oxidative leucine disposal (NOLD) were assessed by measuring L-[1-13C]leucine kinetics. A positive leucine balance, that is the difference between NOLD and leucine Ra, indicated anabolism.

RESULTS

After surgery, leucine Ra in the nutrition group was lower than that in the glucose only group (mean(s.d.) 88(25) versus 131(22) micromol per kg per h). The leucine balance remained negative in the glucose only group, whereas it became positive in the nutrition group (mean(s.d.) -24(3) versus 38(12) micromol per kg per h; P < 0.001).

CONCLUSION

Patients who receive hypocaloric parenteral nutrition can be rendered anabolic after colorectal surgery in the presence of epidural analgesia.

Intraoperative protein sparing with glucose

We examined the hypothesis that glucose infusion inhibits amino acid oxidation during colorectal surgery. We randomly allocated 14 patients to receive intravenous glucose at 2 mg·kg−1·min−1 (glucose group) starting with the surgical incision or an equivalent amount of normal saline 0.9% (control group). The primary endpoint was whole body leucine oxidation; secondary endpoints were leucine rate of appearance and nonoxidative leucine disposal as determined by a stable isotope tracer technique (l-[1-13C]leucine). Circulating concentrations of glucose, lactate, insulin, glucagon, and cortisol were measured before and after 2 h of surgery. Leucine rate of appearance, an estimate of protein breakdown, and nonoxidative leucine disposal, an estimate of protein synthesis, decreased in both groups during surgery ( P < 0.05). Leucine oxidation intraoperatively decreased from 13 ± 3 to 4 ± 3 μmol·kg−1·h−1 in the glucose group ( P < 0.05 vs. control group) whereas it remained unchanged in the control group. Hyperglycemia during surgery was more pronounced in patients receiving glucose (9.7 ± 0.5 mmol/l, P < 0.05 vs. control group) than in patients receiving normal saline (7.1 ± 1.0 mmol/l). The administration of glucose caused an increase in the circulating concentration of insulin ( P < 0.05) resulting in a lower glucagon/insulin quotient than in the control group ( P < 0.05). Intraoperative plasma cortisol concentrations increased in both groups ( P < 0.05), whereas plasma concentrations of lactate and glucagon did not change. The provision of small amounts of glucose was associated with a decrease in amino acid oxidation during colorectal surgery.

Postoperative protein sparing with epidural analgesia and hypocaloric dextrose

OBJECTIVE

We examined the hypothesis that epidural analgesia prevents the increase in amino acid oxidation after elective colorectal surgery in patients receiving hypocaloric infusion of dextrose.

SUMMARY BACKGROUND DATA

Increased oxidative protein loss after surgery may adversely affect postoperative outcome. We have previously shown that effective segmental pain relief by epidural analgesia improves postoperative substrate utilization, resulting in less protein catabolism.

METHODS

We randomly allocated 10 patients to receive general anesthesia combined with epidural analgesia using bupivacaine/fentanyl and 10 to receive general anesthesia followed by patient-controlled analgesia with intravenous morphine. All patients received a peripheral 72-hour infusion of dextrose 10% from the day before until the second day after surgery. The dextrose infusion rate was adjusted to provide 50% of the patients' resting energy expenditure. The primary end point was whole-body leucine oxidation as determined by a stable isotope tracer technique (l-[1-C]leucine).

RESULTS

In the intravenous analgesia group, leucine oxidation increased from 19 +/- 4 to 28 +/- 6 micromol kg h after surgery. Epidural analgesia prevented this increase of leucine oxidation (preoperative 21 +/- 6 micromol kg h, postoperative 21 +/- 5 micromol kg h). This difference was statistically significant (P = 0.01; analysis of variance for repeated measures).

CONCLUSION

Perioperative epidural analgesia and hypocaloric dextrose infusion suppress the postoperative increase in amino acid oxidation, thereby saving more than 100 g of lean body mass per day.

Patient selection in ambulatory anesthesia — An evidence-based review: part II

PURPOSE

This is the second of two reviews evaluating the management of patients with selected medical conditions undergoing ambulatory anesthesia and surgery. Conditions highlighted in this review include: diabetes mellitus; morbid obesity; the ex-premature infant; the child with an upper respiratory infection; malignant hyperthermia; and the use of monoamine oxidase inhibitors.

SOURCE

Medline search strategies and the framework for the evaluation of clinical evidence are presented in Part I.

PRINCIPAL FINDINGS

Diabetes mellitus has not been linked with adverse events following ambulatory surgery. The morbidly obese patient is at an increased risk for minor respiratory complications in the perioperative period but these events do not increase unanticipated admissions. The ex-premature infant may be considered for ambulatory surgery if post-conceptual age is > 60 weeks and hematocrit is > 30%. The child with a recent upper respiratory tract infection is at an increased risk for perioperative respiratory complications, particularly if endotracheal intubation is required. Patients with malignant hyperthermia may undergo outpatient surgery but require four hours of postoperative temperature monitoring. Sporadic cases of drug interactions have been reported when meperidine and indirect-acting catecholamines are administered in the presence of monamine oxidase inhibitors. Ambulatory anesthesia and surgery is safe if these combinations of drugs are avoided.

CONCLUSION

Ambulatory anesthesia can be performed in, and is being offered to, a variety of patients with significant coexistent disease. In many cases there is little evidence documenting the outcomes expected in such patients. Prospective observational and interventional trials are required to better define perioperative management.

Sevoflurane versus isoflurane--anaesthesia for lower abdominal surgery. Effects on perioperative glucose metabolism

BACKGROUND

The aim of this study was to determine the impact of sevoflurane anaesthesia on metabolic and endocrine responses to lower abdominal surgery.

METHODS

A prospective randomized controlled study in 20 patients undergoing abdominal hysterectomy. Patients were randomly assigned to receive either sevoflurane (S) or isoflurane anaesthesia (I). Using a stable isotope dilution technique, endogenous glucose production (EGP) and plasma glucose clearance (GC) were determined pre- and postoperatively (6,6-2H2-glucose). Plasma concentrations of glucose, insulin, cortisol, epinephrine and norepinephrine were measured preoperatively, 5 min after induction of anaesthesia, during surgery and 2 h after the operation.

RESULTS

EGP increased in both groups with no intergroup differences (preop. S 12.2 +/- 1.6, I 12.4 +/- 1.6; postop. S 16.3 +/- 1.9*, I 19.0 +/- 3.1* micromol kg(-1) min(-1), all values are means +/- SD, *P < 0.05 vs. preop.). Plasma glucose concentration increased and GC decreased in both groups. There were no differences between groups. (Glucose conc. mmol l(-1) preop.: S 4.1 +/- 0.3, I 3.9 +/- 0.5; 5 AI S 5.1 +/- 0.6*, I 5.1 +/- 1.0*, postop. S 7.0 +/- 1.0*, I 7.1 +/- 1.4*; * = P < 0.05 vs. preop.; GC ml kg(-1)min(-1) preop. S 3.0 +/- 0.4, I 3.2 +/- 0.4; postop. S 2.4 +/- 0.3*, I 2.7 +/- 0.3*; *=P < 0.05 vs. preop.) Insulin plasma concentrations were unchanged. Cortisol plasma concentrations increased intra- and postoperatively with no changes between the groups. Norepinephrine plasma concentration increased in the S group after induction of anaesthesia. I group norepinephrine was increased 2 h after operation and showed no intergroup differences.

CONCLUSION

Sevoflurane, as well as isoflurane, does not prevent the metabolic endocrine responses to surgery.

Epidural anaesthesia and analgesia - effects on surgical stress responses and implications for postoperative nutrition

BACKGROUND

Surgical injury leads to an endocrine-metabolic and inflammatory response with protein catabolism, increased cardiovascular demands, impaired pulmonary function and paralytic ileus, the most important release mechanisms being afferent neural stimuli and inflammatory mediators.

RESULTS

Epidural local anaesthetic blockade of afferent stimuli reduces endocrine metabolic responses, and improve postoperative catabolism. Furthermore, dynamic pain relief is achieved with improved pulmonary function and a pronounced reduction of postoperative ileus, thereby providing optimal conditions for improved mobilization and oral nutrition, and preservation of body composition and muscle function. Studies integrating continuous epidural local anaesthetics with enforced early nutrition and mobilization uniformly suggest an improved recovery, decreased hospital stay and convalescence.

CONCLUSIONS

Epidural local anaesthetics should be included in a multi-modal rehabilitation programme after major surgical procedures in order to facilitate oral nutrition, improve recovery and reduce morbidity.

Integrated analysis of protein and glucose metabolism during surgery: effects of anesthesia

The aim of this study was to assess dynamic changes in protein and glucose metabolism during surgery. Twelve patients undergoing colorectal surgery received either intravenous propofol anesthesia (n = 6) or inhalational anesthesia with desflurane (n = 6). Pre- and intraoperative protein and glucose kinetics were analyzed by an isotope dilution technique using L-[1-(13)C]leucine and [6,6-(2)H(2)]glucose. Plasma concentrations of glucose, lactate, free fatty acids, insulin, glucagon, and cortisol were measured before and after 2 h of surgery. The rates of appearance of leucine and glucose, leucine oxidation, protein synthesis, and glucose clearance decreased during surgery, independent of the type of anesthesia (P < 0.05). A correlation between the rate of appearance of leucine and glucose was observed (r = 0.755, P < 0.001). Intraoperative plasma cortisol and glucose concentrations increased (P < 0.05), whereas plasma concentrations of lactate, free fatty acids, insulin, and glucagon did not change. Surgery causes a depression of whole body protein and glucose metabolism, independent of the anesthetic technique. There is a correlation between perioperative glucose production and protein breakdown.