Is elevated blood glucose a marker of occult tissue hypoperfusion in off-pump coronary artery bypass grafting?

CONTEXT: Hyperglycemia has been found to occur during myocardial infarction and cardiac surgery even in nondiabetic patients. These being essentially stressful processes associated with hypoperfusion, we decided to find a possible relationship between the occurrence of global tissue hypoperfusion (GTH) and elevated blood glucose level in adult nondiabetic patients undergoing elective off-pump coronary artery bypass grafting (CABG). AIMS: This study aims to observe for the occurrence of global tissue hypoperfusion and its effect on blood glucose level and whether raised blood glucose level can be used as a marker for GTH. DESIGN: Prospective, observational study. SETTINGS: Cardiothoracic operation theater and intensive care unit of a tertiary care teaching hospital. MATERIALS AND METHODS: The occurrence of global tissue hypoperfusion were detected with the help of combined markers of mixed venous oxygen saturation and arterial lactate level at various perioperative study points together with arterial blood glucose level. Blood glucose level compared between the patients with and without GTH. STATISTICAL ANALYSIS USED: Numerical variables were compared between groups by Student's t-test and categorical variables by Fisher's exact test. Two-tailed P ≤ 0.05 was considered for statistically significant. RESULTS: The incidence of GTH was 67%. Blood glucose level was raised in patients with GTH at some study time points but with poor sensitivity and specificity values. CONCLUSIONS: Global tissue hypoperfusion is a common occurrence in even nondiabetic patients undergoing elective off-pump CABG. A relationship exists between rise in blood glucose level and global tissue hypoperfusion in such patients, although it cannot be viewed as marker of the same.

Prophylactic amiodarone vs dronedarone for prevention of perioperative arrhythmias in offpump coronary artery bypass grafting: A pilot randomized controlled trial.

The aim of this study was to compare the effects of prophylactic dronedarone and amiodarone in prevention of arrhythmias during and following off-pump coronary artery bypass grafting (OPCAB). This randomized, controlled, double-blinded, parallel-group study was carried out on 36 adult male patients aged 30-70 years, with modified Parsonnet score 0-10 undergoing offpump coronary artery bypass grafting. After obtaining approval from the institutional ethics committee and informed consent, the patients were randomly allocated to two equal groups (n=18). In one group, patients were given inj. amiodarone 3mg/kg in 100ml of normal saline prior to skin incision intravenously over 20 minutes. In the second group patients received tablet dronedarone 400mg orally twice daily, commencing three days prior to the date of surgery. Patients in the amiodarone group received placebo tablet while patients in the dronedarone group received placebo infusion for the sake of blinding. The frequency and profile of arrhythmias intraoperatively and 24 hours postoperatively were studied. Intraoperative arrhythmias occurred in 50% of patients receiving amiodarone and 16.67% of patients receiving dronedarone. Maximum ventricular rate during atrial fibrillation was significantly lower in the dronedarone group (121 beats per min) than in the amiodarone group (168 beats per min). The study concludes that dronedarone appears to be at least as effective as amiodarone in prophylaxis of intraoperative and postoperative arrhythmias in patients undergoing OPCAB, with a better control of ventricular response.

Effect of Vitamin C on adrenal suppression by etomidate induction in patients undergoing cardiac surgery: A randomized controlled trial.

INTRODUCTION: Etomidate is usually preferred in the induction of cardiac compromised patients due to its relative cardiovascular stability. However, the use of this drug has been limited as etomidate induces suppression of cortisol biosynthesis as a result of blockade of 11-beta-hydroxylation in the adrenal gland, mediated by the imidazole radical of etomidate. This study was carried out to observe the effect of Vitamin C on adrenal suppression after etomidate induction in patients undergoing cardiac surgery. MATERIALS AND METHODS: A total of 78 patients were randomly distributed into two groups. Group-I received oral Vitamin C (500 mg) twice daily and Group-II received antacid tablet as placebo twice daily instead of Vitamin C for 7 consecutive days prior to surgery till morning of surgery. Patients of both the groups induced with etomidate (0.1-0.3 mg/kg). Blood cortisol was estimated at different points of time till 24 th postinduction hour/blood lactate, glucose, hemodynamic parameters, and perioperative outcomes were assessed. RESULTS: Data of seventy patients (n = 35 in each group) were finally analyzed. Cortisol level is statistically significantly higher in Group-I (69.51 ± 7.65) as compared to Group-II (27.74 ± 4.72) (P < 0.05) in the 1 st postinduction hour. In Group-II, cortisol was consistently lower for 1 st 24 postinduction hour. Total adrenaline requirement was statistically significantly high in Group-II. Time of extubation, length of Intensive Care Unit stay arrhythmia was similar in both the groups. CONCLUSION: Vitamin C effectively inhibits etomidate-induced adrenal suppression in cardiac patients, thereby etomidate can be used as a safe alternative for induction in cardiac surgery under cardiopulmonary bypass when pretreated with Vitamin C.

Effect of prophylactic amiodarone in patients with rheumatic valve disease undergoing valve replacement surgery.

The study was carried out to evaluate the effect of prophylactic single-dose intravenous amiodarone in patients undergoing valve replacement surgery. Maintenance of sinus rhythm is better than maintenance of fixed ventricular rate in atrial fibrillation (AF) especially in the presence of irritable left or right atrium because of enlargement. Fifty-six patients with valvular heart disease with or without AF were randomly divided into two groups. Group I or the amiodarone group (n=28) received amiodarone (3 mg/kg in 100 ml normal saline) and group II or the control group received same volume of normal saline. The standardized protocol for cardiopulmonary bypass was maintained for all the patients. AF occurred in 7.14% patients in group I, and in group II, 28.57% (P=0.035); ventricular tachycardia/fibrillation was observed in 21.43% patients in group I and 46.43% patients in group II (P=0.089) after release of aortic clamp. Most of the patients in group I (92.86%) maintained sinus rhythm without cardioversion or defibrillation after release of aortic cross clamp (P=0.002). Defibrillation or cardio version was needed in 7.14% patients in group I and 28.57% patients in group II (P=0.078). A single prophylactic intraoperative dose of intravenous amiodarone decreased post bypass arrhythmia in this study in comparison to the control group. Single dose of intraoperative amiodarone may be used to decrease postoperative arrhythmia in open heart surgery.

Effect of magnesium infusion on thoracic epidural analgesia.

INTRODUCTION: Patients of lung volume reduction surgery (LVRS) having an ASA status III or more are likely to be further downgraded by surgery to critical levels of pulmonary function. AIM: To compare the efficacy of thoracic epidural block with (0.125%) bupivacaine, fentanyl combination and (0.125%) bupivacaine, fentanyl combination with adjunctive intravenous magnesium infusion for the relief of postoperative pain in patients undergoing LVRS. METHODS: Patients were operated under general anesthesia. Thirty minutes before the anticipated completion of skin closure in both groups, (Group A and Group B) 7 ml of (0.125%) bupivacaine calculated as 1.5 ml/thoracic segment space for achieving analgesia in dermatomes of T4, T5, T6, T7, and T8 segments, along with fentanyl 50 µg (0.5 ml), was administered through the catheter, activating the epidural block, and the time was noted. Thereafter, in patients of Group A, magnesium sulfate injection 30 mg/kg i.v. bolus was followed by infusion of magnesium sulfate at 10 mg/kg/hr and continued up to 24 hours. Group B was treated as control. RESULTS AND ANALYSIS: A significant increase in the mean and maximum duration of analgesia in Group A in comparison with Group B (P<0.05) was observed. Total epidural dose of fentanyl and bupivacaine required in Group A was significantly lower in comparison with Group B in 24 hours. DISCUSSION: Requirement of total doses of local anesthetics along with opioids could be minimized by magnesium infusion; therefore, the further downgradation of patients of LVRS may be prevented. CONCLUSION: Intravenous magnesium can prolong opioid-induced analgesia while minimizing nausea, pruritus, and somnolence.

Controlled transient respiratory arrest along with rapid right ventricular pacing for improving balloon stability during balloon valvuloplasty in pediatric patients with congenital aortic stenosis--a retrospective case series analysis.

Rapid right ventricular pacing is safe, effective, and established method to provide balloon stability during balloon aortic valvuloplasty (BAV). Controlled transient respiratory arrest at this point of time may further reduce left ventricular stroke volume, providing an additional benefit to maintain balloon stability. Two groups were studied. Among the 10 patients, five had rapid pacing alone (Group A), while the other five were provided with cessation of positive pressure breathing as well (Group B). The outcomes of BAV in the two groups of patients were studied. One patient in Group A had failed balloon dilatation even after the fourth attempt, while in Group B there were no failures. The peak systolic gradient reduction was higher in Group B (70.05% in comparison to 52.16% of group A). In Group A, five subjects developed aortic regurgitation (grade 2 in four and grade 3 in one, while no grade 3 aortic regurgitation developed in any patient in Group B). Controlled transient respiratory arrest along with rapid ventricular pacing may be effective in maintaining balloon stability and improve the outcome of BAV.

Femoro-femoral cardiopulmonary bypass for the resection of an anterior mediastinal mass.

The perioperative management of patients with mediastinal mass is challenging. Complete airway obstruction and cardiovascular collapse may occur during the induction of general anaesthesia, tracheal intubation, and positive pressure ventilation. The intubation of trachea may be difficult or even impossible due to the compressed, tortuous trachea. Positive pressure ventilation may increase pre-existing superior vena cava (SVC) obstruction, reducing venous return from the SVC causing cardiovascular collapse and acute cerebral oedema. We are describing here the successful management of a patient with a large anterior mediastinal mass by anaesthetizing the patient through a femoro-femoral cardiopulmonary bypass (fem-fem CPB).

Analgesia in post-thoracotomy patients: Comparison between thoracic epidural and thoracic paravertebral blocks.

BACKGROUND: Acute postoperative pain can cause detrimental effects on multiple organ systems, leading to chronic pain syndromes. OBJECTIVE: To compare thoracic epidural block (TEB) and paravertebral block (PVB) for relief of postoperative pain in adult patients undergoing thoracotomy. MATERIALS AND METHODS: In this randomized, single-blinded, prospective study, 60 adult patients of both sexes, belonging to ASA physical status I and II, were scheduled for elective thoracotomy under general anesthesia. They were randomly divided into two groups, A and B of 30 each, who were comparable in terms of demographic parameters and body weight. Group A received TEB and Group B received PVB. All the patients underwent thoracotomy under general anesthesia using a uniform standard anesthetic technique. Thirty minutes before the anticipated end of skin suture, blocks were activated in both the groups with 7.5 ml for TEB and 15 ml for thoracic PVB of 0.25% bupivacaine, along with 1 ml of fentanyl for postoperative analgesia. RESULTS: Patients receiving PVB for postoperative analgesia experienced better analgesia than those receiving TEB from the immediate postoperative period that lasted longer. Intragroup comparison showed that in the cases receiving TEB, there was a significant statistical difference in preoperative and postoperative values with regard to the mean systolic blood pressure (SBP), mean arterial pressure and mean pulse rate. However, in patients receiving PVB, significant difference in preoperative and postoperative values was seen in mean SBP only. CONCLUSIONS: We observed longer duration of analgesia with PVB compared to TEB.

A Comparative Study to Determine the Effect of Intravenous Magnesium on Postoperative Bleeding after on Pump CABG in Patients Receiving Pre-Operative Aspirin.

SUMMARY: Hypomagnesaemia is a common complication after cardiopulmonary bypass (CPB) and predisposes to the development of cardiac arrhythmias. Previous studies showed that intravenous magnesium reduces the incidence of postoperative cardiac arrhythmias but it also inhibits platelet function. Our aim was to compare the postoperative blood loss in patients not receiving magnesium after CPB with the group who received magnesium and to compare the requirement of blood, fresh frozen plasma (FFP) and platelets within 24 hours after surgery. This prospective randomized controlled study was conducted in 80 adult patients on oral aspirin undergoing elective CABG requiring CPB. Group A patients had not received magnesium infusion after recovery from CPB. Group B patients received magnesium infusion after recovery from CPB. Postoperative bleeding was assessed in both the groups. All the data were statistically analyzed. There was a insignificant increase in 24 hours postoperative drainage in magnesium recipient group compared to control group (p>0.05). Requirements of blood and blood products to maintain haematocrit and coagulation profile revealed insignificant (p > 0.05). Increase in requirement of PRC, FFP and platelets in magnesium recipient patients than the control group. Incidence of atrial fibrillation (Gr A 2.5%, Gr B 2.5%) and atrial extrasystoles (Gr A 2.5%, Gr B 10%) revealed comparable (p > 0.05) between the groups, but incidence of ventricular arrhythmias were significantly (p<0.05) high in the patients of Gr A(17.5%) than Gr B(5%). To conclude, magnesium may be administered to patients who continue pre-operative aspirin to undergo on-pump CABG surgery.

Perioperative management of pregnant patients with heart disease for caesarian section under anaesthesia.

One hundred pregnant patients, of age group 22 to 35 years, with different types of cardiac ailments (mitral stenosis, mitral regurgitation, mitral valve prolapse, aortic regurgitation, atrial septal defect, ventricular septal defect, coarctation of the aorta, Eisenmenger syndrome, hypertrophic obstructive cardiomyopathy and operated tetralogy of fallot), put up for elective caesarian section underanaesthesia, were managed in the department of anaesthesiology at IPGME&R/SSKM Hospital, Kolkata from January 1996 to December 2002. The aim of the study was to observe the maternal and foetal outcome in different heart diseases. Death occurred in 2 patients (67%) with Eisenmenger syndrome, in one patient (20%) with hypertrophic obstructive cardiomyopathy and in one patient (5%) with critical mitral stenosis (mitral orifice area = 0.6 cm2) with pulmonary arterial hypertension (PAH). Neonatal mortality was observed in 4 patients [Eisenmenger syndrome--3 (100%); coarctation of the aorta--1 (33%)]. Another 8 patients developed severe heart failure (HF) [severe mitral stenosis (mitral orifice area = 1-1.2 cm2)--2 (10%); hypertrophic obstructive cardiomyopathy--4 (80%); coarctation of the aorta--2 (66%)]. Foetal dysmaturity was observed in 20 neonates (54%) belonging to mothers of New York Heart Association (NYHA) classes III and IV. Congenital heart disease (ventricular septal defect) was detected in 3 offsprings (20%) of mothers with ventricular septal defect. The study concludes that most pregnant cardiac patients can have a satisfactory outcome with careful perioperative management.