Effect of epidural analgesia on metabolic response to major upper abdominal surgery

The Effects of Dexmedetomidine Administration on Postoperative Blood Glucose Levels in Diabetes Mellitus Patients Undergoing Spinal Anesthesia: A Pilot Study

Background

Dexmedetomidine (DEX) is an α2-adrenergic receptor agonist with sedative and sympatholytic effects. It inhibits the stress response and insulin secretion. Therefore, postoperative changes to blood glucose levels were investigated when DEX was intraoperatively infused for sedation purposes in diabetic patients under spinal anesthesia.

Methods

Twenty diabetic patients were randomly allocated to two groups (n = 10). Group A patients were infused with DEX at a dose of 0.4 - 0.8 μg/kg/hour and group B (control) patients were infused with the same volume of normal saline. The blood glucose levels were measured preoperatively and at 1, 3, 6, 12, and 24 hours postoperatively.

Results

There was no statistically significant difference between the blood glucose levels in groups A and B up to 24 hours postoperatively (P = 0.088). A statistically significant difference in the blood glucose level was not demonstrated 24 hours after surgery in comparison with the baseline level in Group A. The blood glucose level significantly decreased at three hours in group B in comparison with the level at baseline (P = 0.007) and increased at 24 hours (P = 0.037).

Conclusions

An intraoperative DEX infusion maintains blood glucose levels at a constant level relative to baseline in diabetic patients within 24 hours postoperatively. The frequency of hyperglycemia was low in group A in the perioperative period compared with that in the control group (group B).

Randomized clinical trial of the effects of immediate enteral nutrition on metabolic responses to major colorectal surgery in an enhanced recovery protocol

BACKGROUND

The effects of immediate postoperative enteral nutrition on postoperative nitrogen balance and insulin resistance were studied in patients subjected to an enhanced-recovery protocol.

METHODS

Eighteen patients undergoing major colorectal surgery in an enhanced-recovery protocol were randomized to immediate postoperative enteral feeding for 4 days with either complete or hypocaloric nutrition. Nitrogen balance and changes in glucose kinetics, substrate utilization (indirect calorimetry) and insulin sensitivity (hyperinsulinaemic-euglycaemic clamp) were measured. Values are mean(s.e.m.).

RESULTS

Mean postoperative urinary nitrogen losses were low (10.7(1.0) versus 10.5(0.7) g per day for complete versus hypocaloric nutrition) and insulin resistance was insignificant (-20(7) versus -27(11) per cent), with no difference between groups. Complete enteral feeding was given without hyperglycaemia (blood glucose concentration 5.8(0.4) versus 5.0(0.4) mmol/l) and resulted in nitrogen balance (+0.1(0.8) versus -12.6(0.6) g nitrogen per day; P < 0.001).

CONCLUSION

This enhanced-recovery protocol was associated with minimal postoperative insulin resistance and nitrogen losses after surgery. Immediate postoperative enteral nutrition was provided without hyperglycaemia and resulted in nitrogen balance.

Reduction of postoperative mortality and morbidity with epidural or spinal anaesthesia: results from overview of randomised trials

OBJECTIVES

To obtain reliable estimates of the effects of neuraxial blockade with epidural or spinal anaesthesia on postoperative morbidity and mortality.

DESIGN

Systematic review of all trials with randomisation to intraoperative neuraxial blockade or not.

STUDIES

141 trials including 9559 patients for which data were available before 1 January 1997. Trials were eligible irrespective of their primary aims, concomitant use of general anaesthesia, publication status, or language. Trials were identified by extensive search methods, and substantial amounts of data were obtained or confirmed by correspondence with trialists.

MAIN OUTCOME MEASURES

All cause mortality, deep vein thrombosis, pulmonary embolism, myocardial infarction, transfusion requirements, pneumonia, other infections, respiratory depression, and renal failure.

RESULTS

Overall mortality was reduced by about a third in patients allocated to neuraxial blockade (103 deaths/4871 patients versus 144/4688 patients, odds ratio=0.70, 95% confidence interval 0.54 to 0.90, P=0. 006). Neuraxial blockade reduced the odds of deep vein thrombosis by 44%, pulmonary embolism by 55%, transfusion requirements by 50%, pneumonia by 39%, and respiratory depression by 59% (all P<0.001). There were also reductions in myocardial infarction and renal failure. Although there was limited power to assess subgroup effects, the proportional reductions in mortality did not clearly differ by surgical group, type of blockade (epidural or spinal), or in those trials in which neuraxial blockade was combined with general anaesthesia compared with trials in which neuraxial blockade was used alone.

CONCLUSIONS

Neuraxial blockade reduces postoperative mortality and other serious complications. The size of some of these benefits remains uncertain, and further research is required to determine whether these effects are due solely to benefits of neuraxial blockade or partly to avoidance of general anaesthesia. Nevertheless, these findings support more widespread use of neuraxial blockade.

Effect of epidural and intravenous clonidine on the neuro-endocrine and immune stress response in patients undergoing lung surgery

The effects of intravenous and epidural clonidine, 4 microg kg-1, combined with epidural morphine, 40 microg kg-1, on the neuro-endocrine and immune stress responses to thoracic surgery are reported. A control group received only epidural morphine. Anaesthesia was induced and maintained with propofol. Catecholamines, vasopressin, cortisol, beta-endorphin concentrations and leucocyte counts were measured before drug administration, immediately after intubation of the trachea, after thoracotomy and at the end of surgery. Catecholamines did not change in any of the groups. The other stress hormones increased during surgery, the pattern being similar in the three groups. Total leucocyte and neutrophil counts were increased in all groups at the end of surgery, but the increase was least in the epidural clonidine group. The number of lymphocytes was reduced at the end of surgery in the epidural and intravenous group, compared with the control group in which the number of lymphocytes did not change. The effects are more pronounced with epidural than with intravenous administration. We conclude that clonidine can modulate the immune stress response to thoracic surgery.

Surgical stress attenuates reflex heart rate response to hypotension

PURPOSE

The baroreflex-mediated increase in heart rate (HR) in response to acute reduction of systolic blood pressure (SBP) was studied in order to assess whether the changes in arterial baroreflex sensitivity depend on the intensity of surgical stress, and location of visceral and somatic stimulation during surgery.

METHODS

Patients were divided into visceral stimulation groups [upper (n = 30) and lower (n = 30) abdominal surgery] and somatic stimulation groups [upper (n = 25) and lower (n = 25) limbs, and chest wall (n = 25) surgery]. Acute hypotension as a baroreflex depressor test was induced by prostaglandin E1 (PGE1) 10 min before surgical incision (control) and during surgical manipulation under isoflurane-N2O anaesthesia or isoflurane-N2O-fentanyl anaesthesia. Plasma level of ACTH was measured in an additional 40 patients who underwent upper abdominal surgery.

RESULTS

During upper abdominal surgery, the heart rate baroreflex sensitivity (delta HR/delta SBP) was depressed from -0.47 +/- 0.05 (control) to -0.01 +/- 0.04 (P < 0.05). The reflex heart rate baroreflex sensitivity remained unchanged and was similar among the remaining groups of patients. The concentration of ACTH increased from 12.5 +/- 1.0 (control) to 343 +/- 78.6 pg.ml-1 (P < 0.05) with isoflurane-N2O anaesthesia but did not change with isoflurane-N2O-fentanyl anaesthesia during upper abdominal surgery.

CONCLUSION

Upper abdominal surgery is associated with the most stressful stimulation to attenuate heart rate baroreflex sensitivity. Integrity of the baroreflex can be preserved by adding opioids to supplement inhalation anaesthesia.

Recovery advantages of regional anesthesia compared with general anesthesia: adult patients

The data support but do not conclusively prove, that RA results in a superior recovery compared with GA. However, several questions need to be answered. Even though the patient may leave the hospital or surgicenter sooner after RA, how does the patient treat pain at home once the block has "worn off"? Since short-acting sedatives and opioids are so commonly used with RA, to what extent is recovery due to them and to what extent is recovery due to the RA alone? Many of the studies examining beneficial effects of RA have been poorly conducted, combining RA with GA and producing inconclusive results. Anesthetic techniques need to be carefully compared to determine whether they are equal in quality, efficiency, and cost. Finally, to determine whether RA is cost-effective, future studies involving ambulatory patients with a focus on outcome and well-being need to be conducted.

Comparison of two anesthesia techniques on perioperative insulin response to i.v. glucose infusion in children

Perioperative blood glucose and insulin levels were measured in children (1-9 years of age) randomly assigned to two groups according to anesthesia technique, general anesthesia (group GA) or general anesthesia combined with regional anesthesia (group RA). Children in the GA group (n = 10) received halothane and opioids, while children of the RA group received epidural anesthesia with bupivacaine (0.25%) and adrenaline combined with halothane anesthesia (n = 10). Children in both groups received 2.5% dextrose in 0.4 N saline administered by volumetric infusion pumps throughout the study period, the infusion rate being adapted to the child's age. Blood samples for glucose and insulin determinations were obtained: at induction, at the end of surgery, and 30, 60 and 120 min after surgery. In response to an identical glucose load, blood glucose levels increased significantly in both groups (P < 0.001), while no differences between groups were observed. Insulin levels did not change significantly postoperatively in the GA group (P = 0.058), while a significant increase was observed in the RA group (P < 0.001). Insulin/blood glucose ratio increased significantly only in the RA group (P < 0.05). The higher insulin secretion in response to glucose infusion in the RA group compared to the GA group may indicate an increased peripheral insulin resistance after regional anesthesia or, more likely, this secretion may be beneficial in contributing to improve postoperative nitrogen balance.

Hypocalcemia in experimental pancreatitis occurs independently of changes in serum nonesterified fatty acid levels

Hypocalcemia and lipid abnormalities commonly occur in acute pancreatitis. Experimentally, increased plasma concentrations of free fatty acids (NEFA) can lower the serum calcium (Ca). We hypothesized that changes in blood-ionized calcium might parallel changes in NEFA concentration in pancreatitis. This hypothesis was tested in a model of severe necrotizing pancreatitis and a model of mild edematous pancreatitis. Adult male Sprague-Dawley rats (300-400 g) were randomized to receive: 100 microL sodium glycodeoxycholic acid (GDOC 34 mmol/L) infused into the pancreatic duct to produce severe necrotizing pancreatitis (Group 1); 100 microL 0.9% NaCl (NS) infused into the pancreatic duct (Group 2); Sham laparotomy (Group 3); A 6 h IV infusion of cerulein (5 mucg/kg/h) to produce mild edematous pancreatitis (Group 4); and a 6 h IV infusion of NS (Group 5). A significant time dependent decrease in blood-ionized Ca concentration, compared to normal rats, was observed in both GDOC-pancreatitis (0.836 +/- .057 vs 1.069 +/- .038 mmol/L p less than 0.001) and cerulein pancreatitis (0.988 +/- .028 vs 1.069 +/- .038 p less than 0.05), which was maximal 24 h after induction of pancreatitis. The degree of hypocalcemia correlated with the severity of pancreatitis (GDOC 0.836 +/- .057 vs cerulein 0.988 +/- .028 p less than .001). Hypocalcemia was not observed in any of the control groups. All experimental and control groups had significantly increased baseline NEFA concentrations compared with normal rats (p less than 0.001); however, no further increase in NEFA concentration occurred in conjunction with the observed time-dependent decline in ionized calcium concentrations. Although the NEFA concentrations observed in these experiments were comparable to those measured in human acute pancreatitis (exclusive of hyperlipemic pancreatitis), the time course of the changes suggests that increases in serum NEFA concentrations in experimental pancreatitis are not the primary factor mediating hypocalcemia.

Effect of epidural analgesia on postoperative insulin resistance as evaluated by insulin clamp technique

The influence of epidural neural blockade on postoperative insulin resistance was studied using the euglycaemic insulin clamp technique. Eighteen patients undergoing elective upper abdominal surgery of moderate severity were allocated to two groups: group G patients underwent operation under general anaesthesia, and postoperative pain was relieved by systemic administration of analgesia; and group E patients received epidural analgesia during surgery and epidural morphine postoperatively. In each patient the euglycaemic insulin clamp test was performed twice: several days before surgery and on postoperative day 1. Peroperative catecholamine and cortisol responses were also measured to investigate possible endocrine mechanisms of the insulin resistance. Glucose disposal (M) decreased in both groups on postoperative day 1 at plasma insulin concentrations ranging from 1.2 to 10.0 milliunits ml-1, resulting in the downward shift of dose-response curves. However, this downward shift was significantly smaller in group E than in group G patients. Urinary adrenaline excretion increased markedly on the day of operation in group G, but was significantly inhibited in group E. Urinary noradrenaline excretion increased mainly on postoperative day 1 in group G, but was significantly inhibited in group E. Plasma cortisol response was lower in group E than in group G during and shortly after operation, and was significantly inhibited in group E on postoperative day 1. These results indicate that insulin resistance after elective abdominal surgery is due to a postreceptor deficit in glucose utilization, as indicated by the downward shift of the dose-response curves. This disturbance in glucose metabolism was reduced by epidural analgesia, the results being associated with inhibited catecholamine and cortisol responses.

Effects of systemic morphine and epidural bupivacaine on postoperative oxygen consumption during rewarming

The alterations in hemodynamics and oxygen consumption as a consequence of continuous epidural infusions of bupivacaine at room temperature and conventionally administered morphine were studied during recovery from general anesthesia for total hip replacement. Twenty-four patients were randomized to receive either bupivacaine or morphine in the recovery room. The bupivacaine group received from 6 to 12 ml per hour of 0.25% bupivacaine epidurally. Patients in the morphine group received 0.1 mg/kg of morphine intramuscularly no more frequently than every 4 hours. A pulmonary artery flotation catheter was inserted into each patient to determine hemodynamics and oxygen consumption at three instances: before analgesia, when pulmonary artery blood temperature reached 36 degrees C, and when it reached 37 degrees C. During the rewarming there was a decrease in mean arterial blood pressure and the systemic vascular resistance index and an increase in heart rate. The whole body oxygen consumption index increased in the bupivacaine group at the last measuring point but was stable in the morphine group. There was no effect on the arterial-venous oxygen content difference in either group. At 37 degrees C, the cardiac index and oxygen consumption index were significantly higher in the bupivacaine group than in the morphine group. In contrast to regional analgesia, systemic morphine administration can partially antagonize cardiovascular response to postoperative rewarming because it induces a stable oxygen demand.

Clinical study of glucose metabolism during partial gastrectomy--comparison between epidural and general anesthesia

Plasma glucose, insulin, glucagon, growth hormone (GH) and cyclic-AMP (C-AMP) were measured in 14 patients undergoing partial gastrectomy under 5 g/hr glucose loading. Seven patients received general anesthesia (GOF; Group G) and the other seven, GO + epidural anesthesia (analgesia Th4-L1; Group E). Blood glucose increased in both groups, although it remained consistently lower in Group E than in Group G. Serum IRI and IRI/glucose ratio appeared consistently higher in Group E than in Group G and a significant difference was found between the two groups at the early period of surgery. The changes in plasma glucagon and GH were found independent of those in glucose. Cyclic-AMP was also consistently higher in Group G than in Group E and a significant difference was observed at the end of anesthesia. These results suggest that epidural anesthesia with 5 g/hr glucose loading may facilitate insulin release from the islet and peripheral blood uptake particularly during the early period of surgery while many other factors such as GH, cortisol and vagal stimulation seemed to be involved in the later period of surgery.

Alfentanil anaesthesia in gall-bladder surgery

Five different dosage schemes for alfentanil administration supplemented with thiopentone, pancuronium and N2O/O2 have been studied in 25 patients undergoing elective cholecystectomy. Six patients in the high dosage group experienced stiff chest during induction and five patients developed respiratory arrest on the recovery ward. The effects of the different schedules in blocking the surgical stress response have been elucidated by serial measurements of serum cortisol and glucose, heart rate and systolic blood pressure. There were no significant changes in serum cortisol, heart rate and blood pressure during anaesthesia and surgery in any group. All patients showed a significant increase in serum cortisol 2 h postoperatively. There was significant elevation of serum glucose after 1 h of surgery in two groups (maintenance dose 1 microgram/kg/min of alfentanil) and in all groups except one (maintenance dose 3.0 micrograms/kg/min) 2 h postoperatively. High dosage of alfentanil resulted in frequent stiff chest during induction and respiratory arrest postoperatively. High dosage did not seem to give any additional benefits in blocking the surgical stress response in this type of surgery.

Endocrine and metabolic responses after standardized moderate surgical trauma: influence of age and sex

The endocrine and metabolic responses to elective cholecystectomy and the influence of age and sex on this stress response were investigated in 21 patients, eight men and 13 women. The patients were divided into two groups, older (n=10) and younger (n=11) than 55 years respectively. Arterial plasma concentrations of catecholamines, cortisol and free fatty acids as well as serum insulin and arterial blood concentrations of glucose, lactate, glycerol, alanine and 3-hydroxybutyrate were measured preoperatively and 2, 24, 48, 72 and 96 h after the start of surgery. Oxygen uptake and CO2 production were measured and respiratory quotient (RQ) was calculated. All hormones and metabolites except insulin and alanine were significantly elevated immediately after surgery. At 24 h plasma noradrenaline and blood glucose were still significantly increased. Serum insulin was increased at 24 and 48 h. Oxygen uptake and plasma cortisol were significantly elevated throughout the period studied and blood alanine was decreased from 2 to 72 h after surgery. The older group showed a significantly higher increase in noradrenaline and lactate, whereas women preoperatively as well as postoperatively had higher glycerol levels. At the end of the period studied women had higher FFA-levels. We conclude that cholecystectomy evokes a significant endocrine and metabolic response and that some of the variables studied are still significantly altered up to 4 days postoperatively. The influence of age and sex on this stress response is of minor importance.

[Continuous peridural anesthesia in children less than 2 years old]

Continuous epidural anaesthesia was carried out in 23 children (age 13.9 +/- 6 months, weight 9.09 +/- 2.5 kg) scheduled for long surgical procedure (soft tissue release for club-foot, "pull-through" for Hirschsprung disease, various genito-urinary procedures). The lumbar epidural space was punctured under general anaesthesia with a 19 G Tuohy needle. A graduated 24 G polyurethane catheter was then inserted and fixed. The local anaesthetic used was bupivacaine 0.25% (0.71 +/- 0.02 ml X kg-1), with or without 1:200,000 adrenaline. Five and 10 min after injection of bupivacaine, heart rate was significantly decreased (p less than 0.05) when compared with pre-induction values, but systolic blood pressure did not change. No other haemodynamic changes occurred. Analgesia was sufficient in all but two cases at incision. Mean duration of surgical procedure was 143 +/- 9.2 min. The time of the first reinjection was significantly longer if bupivacaine with adrenaline was used (116 +/- 2.34 min), when compared with bupivacaine without adrenaline (68.9 +/- 3.92 min) (p less than 0.001). No systemic analgesic was needed during the surgical procedure and anaesthesia was maintained either with halothane (inspiratory fraction less than 0.5%) or enflurane (inspiratory fraction less than 0.8%). All children were extubated at the end of the surgical procedure. The catheter was maintained in 16 children for postoperative analgesia. The first postoperative injection was given 7.1 +/- 0.45 h later. The catheter remained in situ 26.7 +/- 4.1 h. No complication was observed. Thus, during surgery, the need for systemic analgesia was avoided and a rapid and safe postoperative recovery was obtained.(ABSTRACT TRUNCATED AT 250 WORDS)

[Influence of epidural anesthesia on postoperative nitrogen sparing in major digestive surgery]

In order to determine the role of epidural anaesthesia on protein sparing, eighteen patients undergoing major visceral surgery were randomly divided into three different groups according to the mode of anaesthesia used (general anaesthesia, epidural anaesthesia, continuous epidural anaesthesia for 24 h). These patients were intravenously fed for five days postoperatively; their nitrogen balance was studied. Compared with the "general anaesthesia" group, only the daily averages of nitrogen balance of the "continuous epidural" group were significantly better. IN order to correlate stress with nitrogen saving, the early evolution of several parameters (cortisol, glucose, prolactin) used as "stress markers" was studied : there was no evidence of any significant difference between the three groups.

Influences of splanchnic nerve blockade on endocrine-metabolic responses to upper abdominal surgery

Twelve patients undergoing gastrectomy received combined epidural and splanchnic nerve blockade (Group E&S), and changes in plasma ACTH, cortisol, glucose and FFA were compared with those undergoing gastrectomy under general anaesthesia (Group G) or epidural analgesia alone (Group E). Plasma ACTH increased in all groups on the day of operation and was significantly higher in Group G than the other groups. Levels of ACTH in Group E&S were lower than Group E, but the differences were not significant. Cortisol response in Group G was most pronounced and prolonged. This cortisol response was significantly attenuated in Group E and was further inhibited in Group E&S. Blood glucose and FFA increased in Groups G and E during the operation but the increase was significantly less in Group E. In Group E&S, glucose and FFA concentrations showed practically no change throughout the study, being significantly lower than in Group E. The results indicated that the splanchnic nerve is responsible for producing endocrine-metabolic responses to gastric surgery even under epidural blockade.