Blood glucose and insulin levels during epidural anaesthesia in children receiving dextrose-free solutions

Summary
This study was designed to evaluate the hyperglycaemic response to surgery in two groups of children undergoing minor surgical procedures and receiving dextrose-free solutions during the perioperative period. Twenty-four unpremedicated children of less than eight years of age were randomly assigned to receive either general anaesthesia using halothane, vecuronium and narcotics (GA group, n = 12) or general anaesthesia (halothane, vecuronium) combined with caudal anaesthesia (RA group, n = 12). In both groups blood glucose and insulin concentrations were measured during inhalational induction (T0), at the end of surgery (T1) and 30, 60, 120 min after surgery (T2, T3, T4). A significant hyperglycaemic response to surgery was observed in the GA group, while no changes in blood glucose were observed in the RA group. The maximal blood glucose value was observed 30 min after completion of surgery. Insulin changes followed closely changes in blood glucose values. This study demonstrates that epidural anaesthesia was effective in reducing the hyperglycaemic response to surgery in children scheduled for minor surgical procedures. The lack of increase in blood glucose values under epidural anaesthesia suggests that blood glucose levels should be monitored during the perioperative period, especially after a prolonged fasting time and when oral intake might be delayed.     

Haemodynamic responses to sevoflurane compared with halothane during inhalational induction in children

We studied the haemodynamic changes during induction of anaesthesia in 50 ASA I and II children (1–12 yrs) undergoing minor elective surgery. The patients were randomly divided into two groups to receive either halothane (n=25) or sevoflurane (n=25) in a mixture of O₂ and N₂O (40:60) for mask induction of anaesthesia. Induction of anaesthesia was performed with an overpressure technique by administering rapid increases of gas concentrations, in increments of 1% up to 7% for sevoflurane and of 0.5% up to 3% for halothane. Induction was smooth and rapid in both groups but characterized by increases in heart rate and systolic blood pressure up to 20% especially in the sevoflurane group (P<0.05); these increases in the latter group were significant compared with baseline and the halothane group (P<0.05). No serious complications were observed. The authors conclude that more children experienced heart rate and blood pressure increases during the early stage of inhalational induction with sevoflurane compared with halothane.     

Insulin resistance is a common denominator of post-transplant diabetes mellitus and impaired glucose tolerance in renal transplant recipients

Background. Post-transplant diabetes mellitus is a known complication of steroid therapy in renal transplant recipients. Both insulin resistance and insulin deficiency have been shown to be necessary for development of post-transplant diabetes mellitus. It is not known whether recipients with impaired glucose tolerance have similar degree of insulin resistance or deficient insulin response as recipients with post-transplant diabetes mellitus. Methods. To address this question, we used an oral glucose tolerance test to categorize 46 renal transplant recipients on triple immunosuppressive medication to groups with normal glucose tolerance, impaired glucose tolerance or post-transplant diabetes mellitus. Insulin sensitivity was measured using a hyperinsulinaemic euglycaemic clamp. Insulin response was calculated from the increase in serum insulin concentration during the oral glucose tolerance test. Results. Twenty-five were categorized to normal glucose tolerance, 15 to impaired glucose tolerance and six to post-transplant diabetes mellitus. There were no statistically significant differences between the groups regarding prednisolone dose, azathiprine dose, use of {beta}-blocker, age, gender, weight, waist-hip ratio, body mass index, donor source, smoking habits, or first-degree relatives with histories of diabetes mellitus. The impaired glucose tolerance and post-transplant diabetes mellitus groups showed a significant reduction in insulin-stimulated glucose disposal rate (mg/kg^.min) compared to the normal glucose tolerance group (4.6±1.6 and 3.4±1.3 respectively vs 7.1±2.4, P<0.05). The insulin response (picomol/l) was not different between the normal glucose tolerance and impaired glucose tolerance groups but was significantly reduced in the post-transplant diabetes mellitus group (448±310 and 450±291 respectively vs 170±128, P<0.05).Conclusion. Insulin resistance is a common denominator of post-transplant diabetes mellitus and impaired glucose tolerance in renal transplant recipients.     

Optimal dose and duration of glucose administration during fasting period preceding surgery in rabbits

Purpose. We examined preoperative glucose administration to establish what dose and cutoff point were optimal for suppression of lipolysis and prevention of hypo- or hyperglycemia. Methods. Rabbits were preoperatively fasted and simultaneously received glucose at a constant rate of 0, 0.1, 0.2, 0.3, or 0.4 g·kg⁻¹·h⁻¹ in fluid infusion for 3 h. Plasma glucose, immunoreactive insulin activity, nonesterified fatty acids, and ketone bodies were measured 0, 1.5, 3 and 4 h after the start of infusion, and hepatic glycogen content was assessed 1 h after cessation of infusion. Results. Fluid infusion without glucose decreased plasma glucose. Glucose administration at more than 0.2 g·kg⁻¹·h⁻¹ caused hyperglycemia (>200 mg·dl⁻¹) in the infusion period; the differences were significant compared with the value at zero time or in the 0 g·kg⁻¹·h⁻¹ group (P < 0.01). The highest dose also raised plasma immunoreactive insulin activity, which was significantly higher than in the 0 g·kg⁻¹·h⁻¹ group (P < 0.01) at the midpoint of the infusion period. Plasma nonesterified fatty acids increased in all groups. The changes were, however, significantly reduced in both the 0.3 and 0.4 g·kg⁻¹·h⁻¹ groups (P < 0.05 and P < 0.01, respectively) by the end of infusion. All these effects of glucose supply, including suppression of lipolysis, disappeared regardless of dose within 1 h after the cessation of infusion. Conclusion. These results suggest that the optimal dose for preoperative glucose infusion, in order to preserve carbohydrate or fat metabolism, is 0.1–0.2 or 0.3 g·kg⁻¹·h⁻¹, respectively, and indicate that administration should not be discontinued until the start of surgery. Received for publication on July 16, 1998; accepted on August 23, 1999     

Parathyroid hormone decreases in vivo insulin effect on glucose utilization

Hyperparathyroidism is associated with impaired glucose tolerance, and parathyroidectomy may improve carbohydrate homeostasis. It has been suggested that parathyroid hormone (PTH) suppresses insulin secretion but it is unclear whether it also interferes with the peripheral action of insulin. To evaluate in vivo effects of PTH on insulinmediated glucose utilization, 15 male Sprague Dawley rats were continuously infused with rat PTH (1–34) using an Alzet miniosmotic pump at a rate of 0.03 nm/hour. Controls were infused with the vehicle alone. Following 5 days of PTH infusion, plasma calcium (Ca) levels were higher in the PTH-infused rats (12.3±0.2 versus 9.9±0.1 mg/dl, P<0.01). On the 5th day, glucose (700 mg/kg) and insulin (0.175 U/kg) were given as a bolus infusion through the left femoral vein, blood samples were obtained from the right femoral vein, and plasma glucose and insulin were measured at basal (0 minutes) and at 2, 5, 10, and 20 minutes postinfusion. Basal, nonfasting glucose levels were higher (166±4 versus 155±4 mg/dL, P<0.04) in the PTH-infused rats but their insulin levels were similar to those of controls (6.5±0.6 versus 5.6 ±0.5 ng/ml). Postinfusions and maximal (2 minutes) glucose and insulin levels were similar in both groups. However, although insulin levels were similar in both groups at all measured time points, glucose levels at 20 minutes were higher in the PTH-treated rats (205±13 versus 173±9; P<0.03). Also, calculated glucose disappearance rates (Kg) were decreased in the PTH-infused rats (4.05±0.3 versus 4.63±0.8; P=0.054), suggesting an impaired peripheral effect of insulin on glucose utilization. To gain insight into the potential contribution of the hypercalcemia or the PTH to these abnormalities, correlation evaluations were performed. Only in PTH-infused rats did plasma Ca correlate with plasma glucose at 0 and 20 minutes (r=0.6, P=0.02; r=0.7, P=0.01) and with the area under the glucose curve (r=0.6, P=0.03) during the glucose-insulin infusion. Also only in PTH-infused rats did PTH correlate with 0 (P=0.07) and 20-minute (P=0.02) plasma glucose levels. There was no correlation between either Ca or PTH and basal insulin levels or the area under the insulin curve in either group. Consequently, we suggest that in the rat, PTH infusion associated with hypercalcemia impairs insulin effect on glucose utilization in vivo and this defect may be induced by the Ca, PTH, or both.This study was presented in part at the 76th Annual Meeting of the Endocrine Society, Anaheim, CA, USA, June 1994.     

What is the optimal dose of glucose administration during minor surgery under sevoflurane anesthesia?

Purpose. We attempted to identify the optimal infusion rate of glucose to maintain an appropriate usage of energy sources during minor surgery after an overnight fast. Methods. Forty patients scheduled for tympanoplasty or skin grafting under sevoflurane anesthesia were assigned to four groups. The patients received a 2-h infusion of either saline or glucose at a rate of 0.1, 0.2, or 0.3 g·kg⁻¹·h⁻¹. Blood samples were collected before the induction of anesthesia, and at 1 and 2 h after the start of the saline or glucose infusion. Plasma glucose, free fatty acid, β-hydroxybutyrate, acetoacetate, and immunoreactive insulin were measured. Results. Plasma glucose concentration increased dose-dependently. Immunoreactive insulin levels increased in the groups receiving 0.2 or 0.3 g·kg⁻¹·h⁻¹ of glucose infusion. Free fatty acid and ketone bodies did not increase in any glucose infusion groups. The arterial ketone body ratio increased to over 1.00 in the groups receiving 0.2 or 0.3 g·kg⁻¹·h⁻¹ of glucose infusion. Glycorrhea was observed only in the group receiving 0.3 g·kg⁻¹·h⁻¹ of glucose. Conclusion. The smaller doses of glucose (0.1–0.2 g·kg⁻¹·h⁻¹) prevented lipolysis and hyperglycemia during minor surgery. Received for publication on March 17, 1999; accepted on September 22, 1999     

Comparison of local and general anesthesia in tension-free (Lichtenstein) hernioplasty: a prospective randomized trial

To compare pulmonary effects, postoperative pain and fatigue, morbidity, patient satisfaction, and cost of different anesthetic techniques for inguinal hernia repair, 50 patients were randomized to local and general anesthesia groups (LA and GA). All patients received the same premedications and the same postoperative analgesic regimen. The standardized postoperative analgesic, intramuscular pyroxicam 20 mg, was given to all patients in the recovery room and an additional 20 mg on the same day was given as requested by each patient. Pulmonary function studies and arterial blood gas analysis were performed 1 h prior to the operation and at the postoperative 8th and 24th hours. All patients underwent Lichtenstein's tension-free hernioplasty. Postoperative pain and fatigue were registered 8 h and 24 h after the operation. A questionnaire was filled out by the patients, and they were asked to give grades for the general comfort of the anesthesia and the surgical procedure (1=worst, 10=best). Postoperative pulmonary function tests were significantly poorer in the GA group both on 8th- and 24th-hour measurements (P<0.05). Patients who underwent LA had significantly lower PCO₂ and higher PO₂ at the postoperative 8th hour (P<0.05). Mean postoperative pain and fatigue scores revealed a significant difference in favor of local anesthesia at only the 8th hour (P<0.05). There were two complications, one in each group (a hematoma in LA and a urinary retention in GA). Patient satisfaction grades were not different in the two groups. We conclude that LA in inguinal hernia repair does not adversely affect pulmonary functions, patients feel less pain, and patient satisfaction is comparable to that with GA. Electronic Publication     

Lactated Ringer with 1% dextrose: an appropriate solution for peri-operative fluid therapy in children

Peri-operative blood glucose, total protein, and electrolytes values were measured in children (3–120 months) scheduled for minor surgery and randomly assigned to three groups according to the type of fluids administered during anaesthesia: children of RL group (n= 27) received lactated Ringer, those of RLD1 group (n= 25), 1% dextrose in lactated Ringer, and those in RLD2.5 group (n= 27), 2.5% dextrose in 0.4 N saline (50% D5, 50% RL) (63 mmol·l^-1). Infusion rate was set according to children's age and weight. Fluids were infused throughout the study with volumetric infusion pumps. Blood samples were obtained at induction (T0), at the end of surgery (T1), 30 and 60 min later (T2, T3). Pre-operative blood values were within the normal ranges except for high total protein values in all groups of children and for asymptomatic hypoglycaemia (2.3 and 2.5 mmol·l^-1) in two children. Blood glucose increased significantly in the three groups post-operatively (P < 0.001), and this increase was related to the amount of glucose infused. Glucose values differed significantly between groups at T1 and T2, while blood glucose values were back to the normal ranges at T2 and T3 in the RL group. Sodium values remained unchanged post-operatively in both RL and RLD1 groups, while a significant decrease was observed in the RLD2.5 group (P < 0.001). Total protein decreased in the three groups post-operatively (P < 0.001) towards normal values. These data suggest that RLD1 is appropriate for peri-operative fluid therapy in children. Its administration at the infusion rate used in this study, resulted in moderate post-operative hyperglycaemia while avoiding the risk of peri-operative hypoglycaemia, maintaining a constant extracellular fluid composition and correcting pre-operative fluid deficit.     

Anesthesia and blood loss in preterm cesarean section: comparison between general and regional anesthesia

Changes in maternal hemoglobin concentrations after cesarean section performed before 35 weeks gestation were analyzed according to the type of anesthesia in a case-control retrospective study. There were 30 mothers who received general anesthesia (GA group) and 30 mothers who received regional anesthesia (RA group). The groups were matched for gestational age at delivery, type of uterine incision, and the use of tocolytic therapy (isoxuprine) before delivery. The indications for delivery were preterm labor or fetal/maternal complications following premature rupture of membranes without labor. There was no significant difference between the GA and RA groups in the pre-operative hemoglobin (11.9+/-1.4 vs 11.6+/-1.1 g/dl) or postoperative hemoglobin (11.1+/-1.7 vs 11.3+/-1.2 g/dl). The GA group, however, demonstrated a significant fall in the postoperative hemoglobin (P < 0.05). The GA group also had a higher incidence of a drop in hemoglobin of > 10% compared to the RA group (46.7% vs 20.0%, P < 0.05). Our results suggest that general anesthesia may be associated with more blood loss than regional anesthesia in cesarean sections performed before 35 weeks.     

Depth of halothane anesthesia potentiates citrate-induced ionized hypocalcemia and adverse cardiovascular events in dogs

The purpose of this study was to determine if depth of halothane anesthesia contributed to the adverse cardiovascular effects of citrate-induced ionized hypocalcemia. Six mongrel dogs were monitored with arterial, central venous, and pulmonary artery flow-directed catheters. Measured end-tidal halothane assured a constant depth of anesthesia, while controlled ventilation and arterial blood gas analysis provided constant acid-base status. Each dog received sodium citrate (USP Fenwal) equivalent to fresh frozen plasma, 1.0 ml.kg-1.min-1, during both deep (D) and light (L) halothane anesthesia. Three dogs received the infusion during L halothane anesthesia first; after a 1-h stabilization period (2.5 h after first infusion) they received a second equivalent infusion during D halothane anesthesia. Three other dogs were studied first with D, then with L halothane. Mean expired halothane (+/- SEM) for group D was 1.52 +/- 0.08%, for group L, 0.85 +/- 0.07%. Significantly greater adverse cardiovascular effects were seen during D halothane anesthesia; four of the six dogs that received citrate during D halothane anesthesia required cessation of the infusion or suffered cardiac arrest. All six infusions during L halothane anesthesia were tolerated. In both groups, significant reductions in ionized calcium [Ca++] (P less than 0.0001) and mean arterial pressure (MAP) (P less than 0.005) were observed; greater reductions in both parameters occurred in group D (P less than 0.0036-0.0005). In group D, but not in group L, cardiac output was depressed compared to baseline (P less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)     

Primary hyperparathyroidism is associated with decreased insulin receptor binding and glucose intolerance

Summary We studied insulin receptor-binding and carbohydrate and metabolism in 15 patients with symptomatic primary hyperparathyroidism in comparison with 20 healthy controls. Insulin binding to monocytes and erythrocytes was measured by radioreceptor-ligand-assay. Furthermore, patients and controls were characterized by testing oral (100 g glucose load) glucose tolerance as well as insulin tolerance (0.1U insulin/kg body weight). Compared with controls, patients with primary hyperparathyroidism exhibited marked hyperinsulinemia (P<0.01) and significantly higher glucose levels (P<0.01) after an oral glucose load. The glucose lowering effect of intravenous insulin was significantly diminished in primary hyperparathyroidism compared with controls (P<0.01). Receptor studies revealed a significantly lower (P<0.01) insulin binding to monocytes and to erythrocytes in patients with primary hyperparathyroidism compared with controls. The present data indicate an insulin-resistant state in primary hyperparathyroidism, which is caused at least in part, by a downregulation of insulin receptors.     

Effect of Chronic Vitamin D Infusion Upon In Vivo Glucose Disposal

We have previously demonstrated that parathyroid hormone (PTH) infusion decreases glucose disappearance rate (K_g) in vivo. Because in the rodent model used it was not possible to determine whether the PTH itself, the induced hypercalcemia, or both contributed to the glucose intolerance, we examined the effect of vitamin D infusion on insulin-mediated glucose disposal. In this model also hypercalcemia is induced but PTH levels are suppressed. Thirty male Sprague Dawley rats were continuously infused with vit D for 5 days using an Alzet miniosmotic pump, at a rate of 9.7 pmol/hour. Thirty controls were infused with the vehicle alone. On the 5th day, glucose 700 mg/kg and insulin 0.35 U/kg were given as a bolus through the left femoral vein and blood samples were obtained from the right femoral vein just prior to and at 2, 5, 10, and 20 minutes post-glucose/insulin infusion. At the end of 5 days, plasma calcium levels were higher in the vit D-infused rats than in the control rats (12.8 ± 0.1 versus 10.0 ± 0.1 mg/dL, P < 0.01) and rat PTH levels were suppressed (2.1 ± 0.1 versus 62 ± 12 pg/ml, P < 0.01). Glucose levels were higher in the vit D animals only at 5 minutes following glucose/insulin bolus (375 ± 7 versus 350 ± 6 mg/dL, P < 0.01) but at no other time. There were no differences between serum insulin levels at any time. Unlike previous findings in PTH-infused rats, K_g (measured from 2 to 20 minutes following glucose/insulin bolus) was not different between groups (4.5 ± 0.3 versus 4.7 ± 0.2, P= 0.92.) A positive correlation between serum calcium and serum glucose was found only at 5 minutes (r = 0.55, P < 0.01) and only in the vit D animals. The areas under the glucose curves approached statistically significant differences (vit D-infused 5258 ± 142 mg/dL/18 minutes versus control 4947 ± 127, P= 0.06.) Analysis of serum glucose data by two-factor analysis of variance (ANOVA) suggests that the two groups differ slightly in glucose values (P= 0.03) but have parallel K_g. In order to define whether different effects of PTH (1–34) and vit D on intracellular calcium [Ca²⁺]_i levels could partly explain the different effects of PTH and vit D infusion on glucose disposal, we investigated the effect of PTH and vit D infusions on basal and concanavalin A (con A)-stimulated changes in mononuclear [Ca⁺²]_i levels. Following 5 days of PTH, vit D, or control infusion, peripheral mononuclear cells were incubated with 50 μg/ml con A. Changes in [Ca⁺²]_i over 5 minutes were calculated by flow cytometric measurement of the calcium sensitive fluo-3 AM dye. Despite achieving significant and comparable degrees of hypercalcemia in the PTH and vit D infused animals, there were no differences in basal or con A-stimulated [Ca⁺²]_i levels from control. Consequently, we conclude that vit D-induced hypercalcemia associated with suppressed PTH levels has mild affects on glucose homeostasis but does not affect glucose disappearance rate in vivo (K_g) as does hypercalcemia induced by PTH infusion, and that neither chronic PTH infusion nor chronic vit D infusion are associated with long-standing changes in [Ca²⁺]_i levels. Received: 24 March 1998 / Accepted: 29 June 1998     

Effect of perioperative control of blood glucose level on patient’s outcome after anesthesia for cardiac surgery

BackgroundBlood glucose control is an important factor in improving outcome of diabetic patients undergoing cardiac surgery.ObjectiveIs to estimate the relation between blood glucose control and perioperative outcomes in these patients.Study designProspective cohort study.MethodsOne hundred diabetic patients undergoing cardiac surgery, were divided equally into group I (control group) in whom no tight glycemic control was done and group II (study group) in which tight glycemic control was done. Patients in the study group received intra-operatively an infusion of rapidly acting insulin according to a modified protocol to keep blood glucose level between 80 and 110 mg/dl and continued in the ICU until complete recovery from anesthesia. Patients in the control group followed the same protocol of insulin infusion only if their peri-operative blood glucose level exceeded 180 mg/dl.ResultsThere was a rise of blood glucose level in the control group patients till the end of operations (mean level = 227 mg/dl). Mean blood glucose level before CPB was comparable in the two groups, but was significantly different after that until extubation. We reported three cases of delayed recovery in the control group compared to one case in the study group. We also recorded four cases of cardiac problems in group I compared to one case in group II (P = 0.044). There was statistically significant difference between groups regarding renal, neurological and surgical post-operative complications.ConclusionTight glycemic control is recommended for better patient’s outcome after cardiac anesthesia.     

Preoperative Fasting of 2 Hours Minimizes Insulin Resistance and Organic Response to Trauma After Video-Cholecystectomy: A Randomized,Controlled, Clinical Trial

Background  Studies showing the improvement of insulin sensitivity by reducing the term of preoperative fasting are mostly done in patients undergoing major operations. More information about the role of shortened preoperative fasting in perioperative metabolism is needed for such elective minor/moderate abdominal procedures as laparoscopic cholecystectomy. We investigated the influence of a carbohydrate-rich drink given 2 h before laparoscopic cholecystectomy on insulin resistance and the metabolic response to trauma. Methods  A group of 21 female candidates (18–65 years old) for elective laparoscopic cholecystectomy were randomized to either an 8 h fasting group (control group: n = 10) or to a group receiving 200 ml of a carbohydrate beverage containing 12.5% (25 g, 50 kcal per 100 ml and approximately 285 mOsm) of maltodextrine 2 h before operation (CHO group: n = 11). Blood samples for various biochemical assays were collected both at induction of anesthesia and after the 10th postoperative hour. Insulin resistance was assessed by the HOMA-IR equation (Insulin (μU/ml) × blood glucose (mg/dl)/405). Results  There were no postoperative complications. Seventy percent (7/10) of the controls and 27.3% (3/11) of the CHO group experienced at least one episode of vomiting (RR = 2.42, 95% Confidence Interval [CI] = 0.88–6.68; P = 0.08). Biochemical analysis showed that serum glucose (P < 0.01), insulin (P < 0.01), lactate/pyruvate ratio (P = 0.03), and triglycerides (P < 0.01) for the control group were higher than for the CHO group. The value of HOMA-IR was significantly greater (P = 0.03) in the conventionally fasted patients than in the CHO group. Conclusions  Abbreviation of the period of preoperative fasting and administration of a carbohydrate beverage diminishes insulin resistance and the organic response to trauma.     

The influence of hyperinsulinaemia on calcium-phosphate metabolism in renal failure

Background. Patients with renal failure are characterized by impaired insulin-mediated glucose uptake. Insulin plays a major role in the maintenance of phosphate homeostasis but it remains to be determined whether in uraemia insulin-dependent renal and extrarenal phosphate disposal is also affected. Methods. The effects of hyperinsulinaemia on serum concentrations of phosphate, ionized calcium and intact PTH as well as renal excretion of calcium and phosphate was studied under euglycaemic conditions (glucose clamp technique) in patients with advanced renal failure and in healthy subjects. Fifteen patients with renal failure (mean serum creatinine 917 &mgr;mol/l) and 12 control subjects were included. All subjects underwent a 3-h euglycaemic clamp with constant infusion of insulin (50 mU/m²/min) following a priming bolus. The urine was collected for 3 h before and throughout the clamp. Results. The tissue insulin sensitivity (M/I) was lower in patients with renal failure than in control subjects (5.3±2.4 vs 6.7±1.8 mg/kg/min per mU/ml, P=0.001) but the phosphate lowering action of insulin was larger in patients with renal failure than in control subjects. Urinary calcium excretion increased (P<0.05) and phosphate excretion did not change during the clamp in both groups. Despite a decrease of serum ionized calcium in the group of patients with renal failure and no change in the control group, plasma PTH fell significantly in both groups but this effect was still significant after 180 min only in the renal failure group. A significant correlation was observed between changes in serum phosphate and PTH induced by hyperinsulinaemia (r=0.48, P<0.01). Conclusions. Phosphate-lowering effect of insulin is well preserved in severe renal failure despite the resistance to insulin-stimulated glucose uptake. The decrease of serum PTH observed during hyperinsulinaemia appears to be independent of serum ionized calcium.     

The independent metabolic effects of halo thane and isoflurane anaesthesia

Twelve healthy, unpremedicated women scheduled for total abdominal hysterectomy were given either isoflurane (n = 6) or halothane (n = 6) anaesthesia. They all general anaesthesia for a period of 3 h, with surgery being carried out only in the last hour. The anaesthesia consisted of thiopentone, pancuronium and a mixture of oxygen–enriched air (Fio₂ = 34%) supplemented with 1 MAC of either isoflurane or halothane. The patients were maintained normothermic, and with an arterial Sao₂ above 95% throughout the period of the study. The following measurements were made before, during and after anaesthesia (with and without surgery): oxygen consumption (Vo₂), carbon dioxide production (Vco₂); circulating concentrations of various hormones (insulin, growth hormone and Cortisol); various metabolites; selected amino acids and albumin; forearm arterio–venous concentration difference of glucose, lactate, free fatty–acids and selected amino acids (four patients in each group). Whole body Vo₂ decreased significantly by over 20% during anaesthesia (with or without surgery), P < 0.05). Although the circulating concentration of most amino acids showed little or no change during anaesthesia alone, there was a tendency for the flux of most metabolites to decrease, and this persisted during surgery (P < 0.05). During anaesthesia alone there was a twofold reduction in the plasma Cortisol concentration (P < 0.05), and a decrease in albumin concentration (P < 0.01). With the onset of surgery, plasma Cortisol concentration increased rapidly (in association with several other hormones and metabolites) but hypoalbuminemia persisted.     

A comparison of sevoflurane to halothane in paediatric surgical patients: results of a multicentre international study

Induction, emergence and recovery characteristics were compared during sevoflurane or halothane anaesthetic in a large (428) multicentre, international study of children undergoing elective inpatient surgical procedures. Two hundred and fourteen children in each group underwent inhalation induction with nitrous oxide/oxygen and sevoflurane or halothane. Incremental doses of either study drug were added until loss of eyelash reflex was achieved. Steady state concentrations of anaesthesia were maintained until the end of surgery when anaesthetic agents were terminated simultaneously. Time variables were recorded for induction, emergence and the first need for analgesia in the recovery room. In addition, in 86 of the children in both groups, venous blood samples were drawn for plasma fluoride levels during and after surgery. There was a trend toward smoother induction (induction of anaesthesia without coughing, breath holding, excitement laryngospasm, bronchospasm, increased secretion, and vomiting) in the sevoflurane group with faster induction (2.1 min vs 2.9 min, P= 0.037) and rapid emergence times (10.3 min vs 13.9 min, P= 0.003). Among the children given sevoflurane, 2% developed bradycardia compared with 11% in the halothane group. Postoperatively, 46% of the children in the halothane group developed nausea and or vomiting versus 31% in the sevoflurane group (P= 0.002). Two children in the halothane group developed cardiac dysrhythmia and were dropped from the study. In addition, a child in the halothane group developed malignant hyperthermia, received dantrolene, and had an uneventful recovery. Mean maximum inorganic fluoride concentration was 18.3 μM˙l^?1. The fluoride concentrations peaked within one h of termination of sevoflurane anaesthetic and returned rapidly to baseline within 48 h. This study suggests that sevoflurane may be the drug of choice for the anaesthetic management of children.     

Usefulness of perioperative blood glucose control in patients undergoing off-pump coronary artery bypass grafting

Objective We investigated the usefulness of perioperative blood glucose control in patients undergoing coronary artery bypass grafting (CABG). Methods DM patients were aggressively treated with intensive insulin therapy to achieve a preoperative fasting blood glucose level of 140 mg/dl and a postoperative level of 200 mg/dl. For comparison, patients were divided as follows: (1) DM group vs. non-DM group, and (2) for mean blood glucose level in the intensive care unit (ICU), lower than 200 mg/dl (IL) vs. 200 mg/dl or higher (IH). Results (1) In the DM group, the amount of insulin (U) used during surgery was greater (P < 0.05), and the duration of ICU stay was longer (P < 0.05). The incidence of all complications was higher in the DM group (P < 0.05). (2) Between the IH group (54) and the IL group (82), the proportion of DM patients was higher in the IH group (75% vs. 38%, P < 0.05). In the IH, the duration of ICU stay (P < 0.01) was longer, and the incidence of all complications was higher (P < 0.05). (3) In the DM group, the incidence of complications tended to be higher in the IH group. The incidence of complications was extremely low in the non-DM group. Conclusion Strict perioperative blood glucose control may help to improve the outcomes of CABG.     

Renal function in surgical patients after administration of low-flow sevoflurane and amikacin

Purpose. Compound A, a degradation product of sevoflurane, is nephrotoxic in rats, while aminoglycosides induce nephrotoxic injury in humans. Combining an aminoglycoside with a known nephrotoxin can enhance nephrotoxicity. We investigated the effects of aminoglycosides on renal function in surgical patients anesthetized with low-flow sevoflurane. Methods. We compared the urinary excretion of several biochemical markers (such as total protein, albumin, β₂-microglobulin, glucose, and N-acetyl-β-glucosaminidase [NAG]) in an amikacin group (n = 18) and a control group (n = 19) of surgical patients anesthetized with low-flow anesthesia (1 l·min⁻¹) with sevoflurane. All patients received cefotiam as an antibiotic perioperatively. In addition, the amikacin group received amikacin, an aminoglycoside, given intravenously twice a day (400 mg per day) from immediately after the induction of anesthesia to day 2 after anesthesia. Results. Duration of anesthesia and mean compound A concentration were 5.2 ± 1.4 h and 27.2 ± 8.7 ppm (mean ± SD) in the amikacin group, and 5.1 ± 1.7 h and 27.1 ± 7.8 ppm in the control group respectively (P > 0.05). The two groups did not differ in clinical laboratory baseline values (blood urea nitrogen and serum creatinine concentration). There were no significant differences between the groups in either the maximum or the average values for the urinary excretion of biochemical markers after anesthesia. Conclusion. Our study demonstrates that there is no synergic effect of compound A and amikacin on nephrotoxicity in humans. Received: February 14, 2001 / Accepted: August 10, 2001     

Inhibition of tumor size by streptozotocin-induced diabetes mellitus

The effects of experimental diabetes mellitus on tumor growth were studied. Male Fischer rats were rendered diabetic with a single intravenous injection of streptozotocin. Ten days later they were inoculated with 10⁶ cells of a methylcholanthrene-induced sarcoma, and tumor growth was observed for 28 days. In three consecutive experiments diabetes selectively inhibited tumor size at Day 28 following inoculation, by 65% (n = 24, P < 0.05), 63% (n = 30, P < 0.001), and 81% (n = 54, P < 0.001) compared to nondiabetic controls. Tumors became palpable in diabetic animals later than in control animals, but palpable tumors grew at a similar rate in the two groups. In diabetic animals with tumors, fasting blood glucose was inversely related to tumor size (r = ?0.80, P < 0.001). This decrease in blood glucose in diabetic animals with large tumors could not be explained by increased insulin or insulin-like activity in serum or tumor extracts. Insulin binding studies to isolated tumor cells showed that tumor cells from diabetic animals had increased numbers of lower-affinity insulin receptors compared to tumor cells from nondiabetic animals. These findings suggest that insulin deficiency or an associated factor in diabetes mellitus causes a marked delay in tumor appearance.