Efficacy of Glucose-Insulin-Potassium Infusion on Left Ventricular Performance in Type II Diabetic Patients Undergoing Elective Coronary Artery Bypass Graft.Dy

BACKGROUND: Glucose-insulin-potassium (GIK) may improve cardiovascular performance after coronary artery bypass graft surgery (CABG). Our study investigated whether an infusion of GIK during elective CABG surgery in type II diabetic patient improved left ventricular performance.    METHODS: We measured left ventricular ejection fraction and troponin (Tn), a myofibrillar structural protein. In this research, after ethics committee approval, 50 patients with type 2 diabetes mellitus (DM) were enrolled into a randomized simple sampling, prospective, double-blind clinical trial study. In the case group, 500 cc dextrose water 5% plus 80 IU regular insulin and 40 mEq KCL were infused at the rate of 30 cc/hr. Patients in control group received 5% dextrose solution at the rate of 30cc/hr. Venous blood samples were taken before induction of anesthesia, after removal of the aortic clamp and before discharging from hospital. The Mann-Whitney-test was used to test for differences in Tn concentration between the groups. Fisher’s exact test was used to determine whether there was a difference in the proportion of patients with a low ejection fraction (<45%) in the case group compared with that in the control group. Changes in potassium and glucose concentrations over time within the groups were examined by ANOVA and paired t-tests. P<0.05 was regarded as significant level for all tests.    RESULTS: In this study, 50 patients with type 2 DM were evaluated in case and control groups. The mean age ± SD in the case group was 57.7 ±9.9 years and in the other group was 61.2 ± 8.4 years. The groups were well-matched for age, sex and number of bypass grafts. Randomization did not give an equal distribution of male and female patients. There wasn’t any significant difference in ejection fraction between the case and control groups before and after CABG (P>0.05). Tn concentration in the case group was 3.3 ± 5.0 and in the control group was 3.9 ± 5.1. There was no significant difference in Tn between the two groups before and after CABG (P>0.05). There was not any significant difference in hospitalization time between the two groups.     CONCLUSION: The results suggested that GIK can’t improve left ventricular performance in routine CABG surgery.      Keywords: Cardiovascular surgery, Glucose-Insulin-Potassium, Cardiac troponin

The Passive Scalar Concentration and Velocity Fields of Isolated Turbulent Puffs

Passive scalar concentration and velocity fields of isolated turbulent puffs were examined experimentally using the planar laser Mie scattering and PIV techniques, respectively. Work in WPI laboratories on reacting, fully-modulated jets has indicated significantly reduced flame lengths for compact puffs in comparison with steady and pulsed jets. Of particular interest is the entrainment and mixing of isolated turbulent puffs away from the nozzle. The present experiments were carried out in order to enhance fundamental understanding of the velocity fields associated with isolated, turbulent puffs. Puffs were generated by injecting air through a 5 mm diameter nozzle into a flow chamber with a weak co-flow. The injection time was varied by the use of a fast-response solenoid valve from 20 ms to 161 ms. Puffs with a Reynolds number of 5,000 were examined in the range of 25 – 75 diameters downstream of the nozzle. The results indicate that as the injection volume increases, puffs evolve from a spherical geometry to one with a tail. The distribution of a passive scalar within the examined turbulent puffs is unlike that in turbulent vortex rings. The half-width of radial concentration profile through the puff center decreases as the injection volume increases. On the other hand, the puff length in the axial direction increases with the injection volume. The results from phase-locked PIV measurements indicate that the largest axial mean velocities and the radial velocity fluctuation are within the central portion of the puff and the largest axial velocity fluctuation are typically present above the puff center. The turbulent shear stress profiles within puffs are antisymmetric about the centerline and the maximum magnitude for the smallest injection volume is 2.5 times the steady jet value. The vorticity fields calculated from phase-locked velocity field data indicate the presence of vorticity throughout the puff volume. The ratio of puff volume flow rate to steady jet at the puff center location was largest for the smallest injection volume. The majority of entrainment into the puff occurs below the puff center while the puff cap pushes out into surrounding fluid. In general, the puff characteristics did not reveal an internal structure analogous to that in the turbulent vortex ring

The effect of oral tizanidine on postoperative pain relief after elective laparoscopic cholecystectomy

Background: Cholecystectomy is considered as the most important and relatively common postoperative pain control often begins in recovery room by using systemic narcotics that may have some side effects. The aim of this study is to evaluate the effect of premedication with oral tizanidine on pain relief after elective laparoscopic cholecystectomy. Materials and Methods: In this double-blinded clinical trial, 70 adults of American Society of Anesthesiologist physiologic state 1 and 2 scheduled for elective laparoscopic cholecystectomy under general anesthesia were studied and randomly divided in two study and control groups. Ninety minutes before the induction of anesthesia, patients received either 4 mg tizanidine (study group) orally in 50cc or the same volume of plain water as a placebo (control group). Then, the vital signs, pain intensity, duration of stay in recovery, and the analgesic consumption were measured and then compared in both groups during 24 h postoperatively. Results: There was no significant difference in patient characteristics, with respect to age, weight, gender, and duration of anesthesia and surgery between the groups (P > 0.05). The pain intensity, need for analgesic drugs (34.57 ± 8.88 mg vs. 101.86 ± 5.08 mg), and the duration of stay in recovery room (67.43 ± 1.59 min vs. 79.57 ± 5.48 min) were significantly lower in tizanidine group than that of the control group. Conclusion: Oral administration of 4 mg tizanidine before laparoscopic cholecystectomy reduces postoperative pain, opioid consumption, and consequence of the duration of stay in recovery room without any complication