Effect of severity of surgery on metabolic control and insulin requirements in insulin-dependent diabetic patients

We have evaluated insulin requirements and the relationshipbetween hormonal variables, changes in blood glucose and insulinrequirements in insulin-dependent diabetic patients undergoingtwo degrees of severity of surgery: minor (vitrectomy) and major(gastrectomy, bowel resection, hip replacement). The study beganjust before induction and ended 2 h after surgery. Blood glucoseconcentrations were comparable in both groups but the totalamount of insulin given was significantly greater in the majorsurgery group. Plasma noradrenaline and cortisol concentrationsincreased significantly during major surgery and there weresignificant correlations between the increase in these counter-regulatoryhormones and the amount of insulin administered. We concludethat the metabolic changes occurring during surgery were small,but at the cost of a marked increase in insulin requirementsduring major surgery. Increased sympathetic nervous system activityseems to have been implicated in the increase in insulin requirements.     

Intraoperative glycaemic control in non-insulin-dependent and insulin-dependent diabetes

We have compared intraoperative glycaemic control, insulin requirementsand metabolic and endocrine variables in 40 non-insulin-dependentdiabetic patients (NIDDM) and 40 insulin-dependent diabeticpatients (NIDDM) undergoing general anaesthesia for electiveprocedures. Two i.v. insulin regimens were used: continuousi.v. infusion (group A: 1.25 u. h^–1) and repeated i.v.boluses (10 u./2 h). Blood concentrations of glucose were measuredevery 15 min from just before induction of anaesthesia until2 h after surgery. Plasma lactate and pyruvate concentrations,ketone bodies, C-peptide and counterregulatory hormones werealso measured. Glycaemia did not differ significantly in thetwo types of diabetes, regardless of the insulin therapy used.The amounts of insulin administered were similar in NIDDM andIDDM. There was no significant difference for other metabolicvariables. Plasma concentrations of growth hormone (GH) increasedsignificantly during surgery, especially in IDDM patients, butthis change did not alter intraoperative glycaemic control.We conclude that mean glycaemic control, insulin requirementsand development of ketone bodies in NIDDM and IDDM patientsdid not differ during the operative period, regardless of theinsulin regimen used. Therefore, during the operative period,it is not necessary to modify the insulin regimen accordingto the type of diabetes. The consequences of increased plasmaGH concentrations on glycaemic control in IDDM patients afteroperation are unknown.     

Comparison of two methods of i.v. insulin administration in the diabetic patient during the perioperative period

We have examined the effects of two types of insulin therapy(continuous i. v. infusion (group A: 1.25 u. h^–1) anddirect i.v. bolus administration of 10 u. every 2 h (group B:10 u./2 h)) on the metabolic and endocrine responses to surgeryin 60 adult diabetic patients undergoing general anaes thesiafor elective procedures. Blood glucose con centrations weremeasured every 15 mm from just before induction of anaesthesiauntil 2 h after surgery. Plasma ketone bodies, lactate, pyruvate.insulin, C-peptide and counter-regulatory hormone concentrationswere measured also. Blood glucose concentrations were comparablein both groups, except at 60 mm, because of fluctuating bloodglucose concentrations in group B. In each group, one patientbecame hyperglycaemic. One case of hypoglycaemia occurred ingroup B. There were no statistically significant differencesfor the other data except for C-peptide. We conclude that, duringthe operative period, the administration of a direct i. v. bolusof insulin 10 u. every 2 h is a simple and effective methodto control blood glucose concentrations; the method can be usedwhen an insulin infusion pump is not available. (Br. J. Anaesth.1994; 72: 5–10)     

Relationship Between Interatrial Conduction Times and Left Atrial Dimension in Patients Undergoing Atrioventricular Stimulation

Interatrial conduction time (IACT) and left atrial dimension (LAD) were determined in 75 patients (41 males, 34 females, mean age 78.2 ± 7,9 years) undergoing atrioventricular (AV) stimulation. The LAD was measured by M mode echocardiography as the distance between the posterior aortic wall and the posterior left atrial wall. The IACT was determined during a transvenous dual chamber pacemaker implant done under local anesthesia (lidocaine). The spontaneous interatrial conduction time (SIACT) was measured from the intrinsic deflection (ID) of the right atrium recorded in a unipolar mode (unipolar J-shaped had positioned in the right appendage) to the ID of the left atrium (bipolar esophageal lead, left atrial positive deflection equal to the negative one) during sinus rhythm. The right atrium then was paced at a rate slightly greater than the spontaneous one. The paced interatrial conduction time (PIACT) was measured from the stimulus artifact to the left atrial ID. The PIACT was also measured during incremental right atrial pacing (10 beats/min step increase to 180 beats/min) and, from these measurements, the maximum increase of PIACT (MIPIACT) was deduced. The LAD was measured at 39.5 ± 8.7 mm, SIACT at 70.3 ± 24.8 msec, PIACT at 118.8 ± 27.9 msec, and MIPIACT at 16.5 ± 16.4 msec. We found highly significant relationships between SIACT and LAD(P = 0.0006, r - 0.39), PIACT and LAD (P = 0.0001, r = 0.45), and MIPIACT and LAD (P = 0.0006, r = 0.38). We also noted that the LAD was greater in patients in whom MIPIACT was >10 msec than in patients in whom the MIPIACT was negligible (P < 0.002). However, the “r” values indicate that IACT is probably determined by multiple factors, and LAD appears to be one of the most important. Thus, we demonstrated the existence of highly significant relationships between the LAD determined by M mode echocardiography and the IACT when sensing and pacing the right atrium. We also demonstrated that the LAD was greater in patients in whom PIACT increased by an appreciable duration during fast atrial pacing. These results must be kept in mind when choosing a mode of stimulation and determining the AV delay (dual chamber pacemaker), particularly in patients with left atrial enlargement in whom the contribution of the atrial contraction and its timing are hemodynamically determinant.     

Interatrial Conduction in Patients Undergoing AV Stimulation: Effects of Increasing Right Atrial Stimulation Rate

To evaluate the frequency of spontaneous or rate dependent interatrial blocks, the interatrial conduction time (IACT) was studied on 100 consecutive patients (mean age 78.3 ±7.8 years) during a transvenous dual chamber pacemaker implant. The spontaneous interatrial conduction time (SIACT) was measured from the intrinsic deflection (ID) of the unipolar right atrial signal to the ID of the left atrial signal recorded in a bipoiar way by an esophageal lead. The paced interatrial conduction time (PIACT) was measured from the stimulus artifact to the left atrial ID, when the atrium was paced at a slightly higher rate than the spontaneous rate and during incremental atrial pacing. From these measurements, the maximum increase ofPIACT (MIPIACT) was deduced. In this elderly population, the PIACT was similar (117 ± 26.9 msec) to the data in the literature. However, there were large interindividual variations that were also found in SIACT. We found a close correlation between SIACT and PIACT (P < 0.0001). PIACT was on average 50 msec longer than SIACT. SIACT increased with age (P < 0.03). The MIPIACT was 15.3 ± 15.2 msec. In the majority of patients, the MIPIACT was > 10 msec, and even reached 90 msec in one patient. MIPIACT was longer in patients with a PIACT exceeding 110 msec (P < 0.004). Based on IACT alone, the AV interval must be lengthened on average by 50 msec when changing from atrial tracking-ventricular pacing to atrial pacing-ventricular pacing, but large individual differences must be kept in mind. Elderly people should probably have a longer AV delay.     

Effects of creatine monohydrate ingestion in sedentary and weight-trained older adults

To investigate the effects of an oral creatine supplementation in older adults, 32 elderly subjects (67–80 years; 16 females, 16 males) were randomly assigned to four equivalent subgroups (control-creatine; control-placebo; trained-creatine; trained-placebo) based on whether or not they took part in an 8-week strength training programme and an 8-week oral creatine monohydrate creatine supplementation programme. The strength training programme consisted of three sets of eight repetitions at 80% of one-repetition maximum, for leg press, leg extension and chest press, 3 days a week. The 52-day supplementation programme consisted of 20 g of creatine monohydrate (or glucose) and 8 g of glucose per day for the initial 5 days followed by 3 g of creatine monohydrate (or glucose), and 2 g of glucose per day. Prior to and after the training and supplementation periods, body mass, body fat, lower limb muscular volume, 1-, 12-repetitions maxima and isometric intermittent endurance tests for leg press, leg extension and chest press were determined. In all groups, no significant changes in anthropometric parameters were observed. For all movements, the increases in 1- and 12-repetitions maxima were greater (P < 0.02) in trained than control subjects. No significant interactions (supplementation/training/time) were observed for the 1-, 12-repetitions maxima, and the isometric intermittent endurance, whatever the movement considered. We conclude that oral creatine supplementation does not provide additional benefits for body composition, maximal dynamical strength, and dynamical and isometric endurances of healthy elderly subjects, whether or not it is associated with an effective strength training.