Thomas Schricker

Epidural Analgesia Enhances Functional Exercise Capacity and Health-related Quality of Life after Colonic Surgery: Results of a Randomized Trial

BACKGROUND Multimodal analgesia programs have been shown to decrease hospital stay, but it not clear which functions are restored after surgery. The objective of this study is to evaluate the impact of epidural anesthesia and analgesia on functional exercise capacity and health-related quality of life. METHODS Sixty-four patients undergoing elective colonic resection were randomized to either patient-controlled analgesia with morphine or thoracic epidural analgesia with bupivacaine and fentanyl (epidural group). All patients in both groups received similar perioperative care and were offered the same amount of postoperative oral nutrition and assistance with mobilization. Primary outcome was functional exercise capacity as measured by the 6-min walking test, and secondary outcome was health-related quality of life, as measured by the SF-36 health survey. These were assessed before surgery and at 3 and 6 weeks after hospital discharge. Other variables measured in hospital included pain and fatigue visual analogue scale, bowel function, time out of bed, nutritional intake, complication rate, readiness for discharge, and length of hospital stay. RESULTS Although the 6-min walking test and the SF-36 physical health component decreased in both groups at 3 and 6 weeks after surgery, the patient-controlled analgesia group experienced a significantly greater decrease at both times (P < 0.01). Patients in the epidural group had lower postoperative pain and fatigue scores, which allowed them to mobilize to a greater extent (P < 0.05) and eat more (P < 0.05). Length of hospital stay and incidence of complications were similar in both groups, although patients in the epidural group were ready to be discharged earlier. CONCLUSIONS The superior quality of pain relief provided by epidural analgesia had a positive impact on out-of-bed mobilization, bowel function, and intake of food, with long-lasting effects on exercise capacity and health-related quality of life.

The Role of the Anesthesiologist in Fast-Track Surgery: From Multimodal Analgesia to Perioperative Medical Care

BACKGROUND:Improving perioperative efficiency and throughput has become increasingly important in the modern practice of anesthesiology. Fast-track surgery represents a multidisciplinary approach to improving perioperative efficiency by facilitating recovery after both minor (i.e., outpatient) and major (inpatient) surgery procedures. In this article we focus on the expanding role of the anesthesiologist in fast-track surgery. METHODS:A multidisciplinary group of clinical investigators met at McGill University in the Fall of 2005 to discuss current anesthetic and surgical practices directed at improving the postoperative recovery process. A subgroup of the attendees at this conference was assigned the task of reviewing the peer-reviewed literature on this topic as it related to the role of the anesthesiologist as a perioperative physician. RESULTS:Anesthesiologists as perioperative physicians play a key role in fast-track surgery through their choice of preoperative medication, anesthetics and techniques, use of prophylactic drugs to minimize side effects (e.g., pain, nausea and vomiting, dizziness), as well as the administration of adjunctive drugs to maintain major organ system function during and after surgery. CONCLUSION:The decisions of the anesthesiologist as a key perioperative physician are of critical importance to the surgical care team in developing a successful fast-track surgery program.

The Association of Preoperative Glycemic Control, Intraoperative Insulin Sensitivity, and Outcomes after Cardiac Surgery

CONTEXT The impairment of insulin sensitivity, a marker of surgical stress, is important for outcomes. OBJECTIVE The aim was to assess the association between the quality of preoperative glycemic control, intraoperative insulin sensitivity, and adverse events after cardiac surgery. DESIGN AND SETTING We conducted a prospective cohort study at a tertiary care hospital. SUBJECTS Nondiabetic and diabetic patients scheduled for elective cardiac surgery were included in the study. Based on their glycosylated hemoglobin A (HbA(1c)), diabetic patients were allocated to a group with good (HbA(1c) <6.5%) or poor (HbA(1c) >6.5%) glycemic control. INTERVENTION We used the hyperinsulinemic-normoglycemic clamp technique. MAIN OUTCOME MEASURES The primary outcome was insulin sensitivity measurement. Secondary outcomes were major complications within 30 d after surgery including mortality, myocardial failure, stroke, dialysis, and severe infection (severe sepsis, pneumonia, deep sternal wound infection). Other outcomes included minor infections, blood product transfusions, and the length of intensive care unit and hospital stay. RESULTS A total of 143 nondiabetic and 130 diabetic patients were studied. In diabetic patients, a negative correlation (r = -0.527; P < 0.001) was observed between HbA(1c) and intraoperative insulin sensitivity. Diabetic patients with poor glycemic control had a greater incidence of major complications (P = 0.010) and minor infections (P = 0.006). They received more blood products and spent more time in the intensive care unit (P = 0.030) and the hospital (P < 0.001) than nondiabetic patients. For each 1 mg x kg(-1) x min(-1) decrease in insulin sensitivity, the incidence of major complications increased (P = 0.004). CONCLUSIONS In diabetic patients, HbA(1c) levels predict insulin sensitivity during surgery and possibly outcome. Intraoperative insulin resistance is associated with an increased risk of complications, independent of the patients diabetic state.

Epidural blockade modifies perioperative glucose production without affecting protein catabolism

Background Epidural blockade with local anesthetic has been shown to blunt the increase in plasma glucose concentration during and after abdominal surgery. The aim of the study was to test the hypothesis that epidural blockade inhibits this hyperglycemic response by attenuating endogenous glucose production. The authors further examined if the modification of glucose production by epidural blockade has an impact on perioperative protein catabolism. Methods Sixteen patients undergoing colorectal surgery received either general anesthesia and epidural blockade with local anesthetic (n = 8) or general anesthesia alone (control, n = 8). Glucose and protein kinetics were assessed by stable isotope tracer technique ([6,6-2H2]glucose, L-[1-13C]leucine) during and 2 h after surgery. Plasma concentrations of glucose, lactate, free fatty acids (FFA), cortisol, glucagon, and insulin were also determined. Results Epidural blockade blunted the perioperative increase in the plasma concentration of glucose, cortisol, and glucagon when compared with the control group (P < 0.05). Plasma concentrations of lactate, FFA, and insulin did not change. Intra- and postoperative glucose production was lower in patients with epidural blockade than in control subjects (intraoperative, epidural blockade 8.2 ± 1.9 vs. control 10.7 ± 1.4 &mgr;mol·kg−1·min−1, P < 0.05; postoperative, epidural blockade 8.5 ± 1.8 vs. control 10.5 ± 1.2 &mgr;mol·kg−1·min−1, P < 0.05), whereas glucose clearance decreased to a comparable extent in both groups (P < 0.05). Protein breakdown (P < 0.05), protein synthesis (P < 0.05), and amino acid oxidation (P > 0.05) decreased with both anesthetic techniques. Conclusions Epidural blockade attenuates the hyperglycemic response to surgery through modification of glucose production. The perioperative suppression of protein metabolism was not influenced by epidural blockade.

Propofol/sufentanil anesthesia suppresses the metabolic and endocrine response during, not after, lower abdominal surgery.

We investigated the influence of propofol/sufentanil anesthesia on metabolic and endocrine responses during, and immediately after, lower abdominal surgery. Twenty otherwise healthy patients undergoing abdominal hysterectomy for benign myoma received either continuous infusions of propofol supplemented with sufentanil (0.01 &mgr;g · kg−1 · min−1, n = 10) or enflurane anesthesia (enflurane, n = 10). Plasma concentrations of glucose, lactate, free fatty acids, triglycerides, insulin, glucagon, cortisol, epinephrine, and norepinephrine were measured before, during, and 2 h after surgery. Pre- and postoperative endogenous glucose production (Ra glucose) was analyzed by an isotope dilution technique by using [6,6-2H2] glucose. Propofol/sufentanil anesthesia prevented the increase in plasma cortisol and catecholamine concentrations and attenuated the hyperglycemic response during surgery without showing any difference after the operation. Mediated through a higher glucagon/insulin quotient (propofol/sufentanil 15 ± 7 versus enflurane 8 ± 4 pg/&mgr;U, P < 0.05), the Ra glucose postoperatively increased more in the propofol/sufentanil than in the enflurane group (propofol/sufentanil 15.6 ± 2.0 versus enflurane 13.4 ± 2.2 &mgr;mol · kg−1 · min−1, P < 0.05). Implications The concept of stress-free anesthesia using propofol combined with sufentanil is valid only during surgery. The metabolic endocrine stress response 2 h after the operation is more pronounced than after inhaled anesthesia.

High-Dose Insulin Therapy Attenuates Systemic Inflammatory Response in Coronary Artery Bypass Grafting Patients

BACKGROUND Cardiac surgery with cardiopulmonary bypass (CPB) induces an acute phase reaction that is implicated in the pathogenesis of several postoperative complications. Studies have shown that proinflammatory cytokines are increased by acute hyperglycemia. Recent evidence suggests that insulin has antiinflammatory properties. Therefore, we hypothesized that high-dose insulin therapy would attenuate the systemic inflammatory response to cardiopulmonary bypass and surgery in coronary artery bypass patients while maintaining normoglycemia. METHODS A total of 52 patients who presented for elective coronary artery bypass were randomized to receive intraoperative intravenous insulin infusion, titrated to maintain blood glucose concentrations less than 180 mg/dL (group I, n = 25), or receive intraoperative fixed high dose of intravenous insulin infusion (5 mU/kg/min) with dextrose 20% infused separately to maintain a blood glucose level between 70 and 110 mg/dL (group II, n = 27). Blood samples were collected at different time points to determine tumor necrosis factor alpha (TNFalpha), interleukin 6 and 8 (IL6 and IL8), and complement factor 3 and 4 (C3 and C4). RESULTS Patients in both groups had similar preoperative characteristics. Patients in the high-dose insulin group had higher blood insulin concentrations and tighter blood glucose control. There were lower levels of IL6 (150 pg/dL vs 245 pg/dL, p = 0.03), IL-8 (49 pg/dL vs 74 pg/dL, p = 0.05), and TNFalpha (2.2 pg/dL vs 3.0 pg/dL, p = 0.04) in group II in the early postoperative period. CONCLUSIONS High-dose insulin therapy blunts the early postoperative surge in inflammatory response to CPB as reflected by decreased levels of IL6, IL8, and TNFalpha.

Understanding the mechanisms by which isoflurane modifies the hyperglycemic response to surgery.

We studied the effect of anesthesia on the kinetics of perioperative glucose metabolism by using stable isotope tracers. Twenty-three patients undergoing cystoprostatectomy were randomly assigned to receive epidural analgesia combined with general anesthesia (n = 8), fentanyl and midazolam anesthesia (n = 8), or inhaled anesthesia with isoflurane (n = 7). Whole-body glucose production and glucose clearance were measured before and during surgery. Glucose clearance significantly decreased during surgery independent of the type of anesthesia. Epidural analgesia caused a significant decrease in glucose production from 10.2 ± 0.4 to 9.0 ± 0.4 &mgr;mol · kg−1 · min−1 (P < 0.05), whereas the plasma glucose concentration was not altered (before surgery, 5.0 ± 0.2 mmol/L; during surgery, 5.2 ± 0.1 mmol/L). Glucose production did not significantly change during fentanyl/midazolam anesthesia (before surgery, 10.5 ± 0.5 &mgr;mol · kg−1 · min−1; during surgery, 10.1 ± 0.5 &mgr;mol · kg−1 · min−1), but plasma glucose concentration significantly increased from 4.8 ± 0.1 mmol/L to 5.3 ± 0.2 mmol/L during surgery (P < 0.05). Isoflurane anesthesia caused a significant increase in plasma glucose concentration (from 5.2 ± 0.1 mmol/L to 7.2 ± 0.5 mmol/L) and glucose production (from 10.8 ± 0.5 &mgr;mol · kg−1 · min−1 to 12.4 ± 1.0 &mgr;mol · kg−1 · min−1) (P < 0.05). Epidural analgesia prevented the hyperglycemic response to surgery by a decrease in glucose production. The increased glucose plasma concentration during fentanyl/midazolam anesthesia was caused by a decrease in whole-body glucose clearance. The hyperglycemic response observed during isoflurane anesthesia was a consequence of both impaired glucose clearance and increased glucose production.

Perioperative glucose infusion and the catabolic response to surgery: the effect of epidural block.

Although the nitrogen-sparing properties of epidural block and i.v. glucose on the days after surgical trauma have been well established, their metabolic effects during the acute phase of the stress response remain unclear. Therefore, in this study we investigated the effect of epidural block on glucose and protein kinetics during and immediately after surgery in patients receiving i.v. glucose at 2 mg x kg(-1) x min(-1). Sixteen patients undergoing colorectal surgery received either general anesthesia with epidural block with bupivacaine (EDA; n = 8) or general anesthesia alone (control; n = 8). Glucose and protein kinetics were determined during and 2 h after the operation by stable isotope tracers [6,6-(2)H(2)]glucose and L-[1-(13)C]leucine. Plasma concentrations of glucose, insulin, cortisol, and glucagon were also determined. Epidural block attenuated the perioperative increase in plasma glucose concentration (P < 0.05). The rate of appearance of glucose (R(a) glucose) and endogenous glucose production (EGP) were slower in the EDA group than in control subjects during (R(a) glucose, EDA 13.2 +/- 1.0 versus control 15.3 +/- 1.8 micromol x kg(-1) x min(-1); P < 0.05; EGP, EDA 1.2 +/- 1.2 versus control 3.8 +/- 1.7 micromol x kg(-1) x min(-1); P < 0.05) and after the operation (P > 0.05). Whereas protein breakdown and amino acid oxidation decreased in both groups (P < 0.05), whole-body protein synthesis remained unchanged. Insulin levels increased with both anesthetic techniques (P < 0.05). Intraoperative plasma concentrations of cortisol and glucagon were smaller in the EDA group (P < 0.05). The intraoperative suppression of EGP by exogenous glucose was more pronounced in the presence of epidural block. However, epidural block failed to exert a protein-sparing effect during the acute phase of the stress response in patients receiving i.v. glucose.

The Anabolic Effect of Epidural Blockade Requires Energy and Substrate Supply

Background The authors examined the hypothesis that continuous thoracic epidural blockade with local anesthetic and opioid, in contrast to patient-controlled intravenous analgesia with morphine, stimulates postoperative whole body protein synthesis during combined provision of energy (4 mg · kg−1 · min−1 glucose) and amino acids (0.02 ml · kg−1 · min−1 Travasol™ 10%, equivalent to approximately 2.9 g · kg−1 · day−1). Methods Sixteen patients were randomly assigned to undergo a 6-h stable isotope infusion study (3 h fasted, 3 h feeding) on the second day after colorectal surgery performed with or without perioperative epidural blockade. Protein synthesis, breakdown and oxidation, glucose production, and clearance were measured by l-[1-13C]leucine and [6,6-2H2]glucose. Results Epidural blockade did not affect protein and glucose metabolism in the fasted state. Parenteral alimentation decreased endogenous protein breakdown and glucose production to the same extent in both groups. Administration of glucose and amino acids was associated with an increase in whole body protein synthesis that was modified by the type of analgesia, i.e., protein synthesis increased by 13% in the epidural group (from 93.3 ± 16.6 to 104.5 ± 11.1 &mgr;mol · kg−1 · h−1) and by 4% in the patient-controlled analgesia group (from 90.0 ± 27.1 to 92.9 ± 14.8 &mgr;mol · kg−1 · h−1;P = 0.054). Conclusions Epidural blockade accentuates the stimulating effect of parenteral alimentation on whole body protein synthesis.

Patient controllediv analgesia is an acceptable pain management strategy in morbidly obese patients undergoing gastric bypass surgery. A retrospective comparison with epidural analgesia

PurposeTo examine the hypothesis that pain treatment with patient controlled analgesia (PCA) usingiv morphine is a suitable and safe alternative to epidural analgesia in morbidly obese patients undergoing gastric bypass surgery. We retrospectively compared the postoperative periods in all patients undergoing this procedure in our institution between November 1999 and November 2001.MethodsAccording to their perioperative pain treatment, patients were assigned to a PCA group (withiv morphine) or an epidural analgesia group, in which patients received either intermittent doses of morphine or continuous infusions of bupivacaine/fentanyl. Study endpoints included quality of pain control, incidence of cardiovascular and respiratory complications, analgesia related side effects, time to ambulation and first flatus, length of hospital stay, and wound infections.ResultsData from 86 patients were analyzed with 40 patients in the PCA group and 46 patients in the epidural group. Groups were similar with respect to age, body mass index, and gender. The type of analgesia did not affect the quality of pain control at rest, the frequency of nausea and pruritus, the time to ambulation and return of gastrointestinal function, and the length of hospital stay. Patients receiving epidural analgesia had a greater risk of wound infection than subjects with PCA (epidural group: 39%, PCA group: 15%,P = 0.01).ConclusionWe conclude that in grossly obese patients undergoing gastric bypass surgery PCA withiv morphine is an acceptable strategy for pain management and may confer some advantages when compared to epidural analgesia.RésuméObjectifVérifier l’hypothèse voulant que le traitement de la douleur par l’analgésie autocontrôlée (AAC), avec de la morphine iv soit appropriée et sans risque pour remplacer l’analgésie péridurale chez les patients atteints d’obésité morbide qui subissent un pontage gastrique.MéthodeNous avons comparé, rétrospectivement, la période postopératoire pour tous les patients qui ont subi cette intervention à notre institution entre novembre 1999 et novembre 2001. Selon l’analgésie périopératoire reçue, les patients ont été assignés à un groupe d’AAC (avec de la morphine iv ) ou à un groupe d’analgésie péridurale, soit avec des doses de morphine intermittentes, soit des perfusions continues de bupivacaïne/fentanyl. Les paramètres étudiés ont été la qualité de l’analgésie, l’incidence de complications cardiovasculaires et respiratoires, les effets secondaires reliés à l’analgésie, la durée écoulée avant le premier lever et le retour du péristaltisme gastrointestinal, la durée du séjour hospitalier et les infections de la plaie chirurgicale.RésultatsLes données de 86 patients ont été analysées, 40 du groupe d’AAC et 46 du groupe d’analgésie péridurale. Les groupes étaient comparables quant à l’âge, l’index de masse corporelle et le sexe. Le type d’analgésie n’a pas affecté la qualité de l’analgésie au repos, la fréquence de nausée et de prurit, le temps écoulé avant de pouvoir se lever et avant le retour du péristaltisme gastrointestinal, et la longueur du séjour hospitalier. Les patients sous analgésie péridurale présentaient un risque plus élevé d’infection de la plaie que les sujets sous AAC (péridurale : 39%, AAC : 15%, P = 0,01).ConclusionChez les patients très obèses, devant subir un pontage gastrique, l’AAC avec de la morphine iv est une stratégie d’analgésie acceptable et peut présenter certains avantages par rapport à l’analgésie péridurale.