Ranjith Baskar Karthekeyan

The effects of dexmedetomidine on attenuation of stress response to endotracheal intubation in patients undergoing elective off-pump coronary artery bypass grafting.

This study was designed to study the efficacy of intravenous dexmedetomidine for attenuation of cardiovascular responses to laryngoscopy and endotracheal intubation in patients with coronary artery disease. Sixty adult patients scheduled for elective off-pump coronary artery bypass surgery were randomly allocated to receive dexmedetomidine (0.5 mcg/kg) or normal saline 15 min before intubation. Patients were compared for hemodynamic changes (heart rate, arterial blood pressure and pulmonary artery pressure) at baseline, 5 min after drug infusion, before intubation and 1, 3 and 5 min after intubation. The dexmedetomidine group had a better control of hemodynamics during laryngoscopy and endotracheal intubation. Dexmedetomidine at a dose of 0.5 mcg/kg as 10-min infusion was administered prior to induction of general anaesthesia attenuates the sympathetic response to laryngoscopy and intubation in patients undergoing myocardial revascularization. The authors suggest its administration even in patients receiving beta blockers.

The effects of preemptive pregabalin on attenuation of stress response to endotracheal intubation and opioid- sparing effect in patients undergoing off-pump coronary artery bypass grafting

The clinical study was designed to evaluate and compare single preoperative dose of pregabalin to a placebo regarding hemodynamic responses to laryngoscopy and endotracheal intubation, to assess perioperative fentanyl requirement and any side-effects. It was a randomized, double-blind, placebo-controlled, parallel assignment, efficacy study. The study was done at a tertiary university hospital. This study was a comparison between two groups of 30 adult patients scheduled for elective off pump coronary artery bypass surgery. In the control group, the patients were given placebo capsules, and in the pregabalin group, the patients were given pregabalin 150 mg capsule orally 1 h before surgery. The patients were compared for hemodynamic changes before the start of the surgery, after induction, 1, 3, and 5 min after intubation. Additionally, fentanyl requirement during surgery and the first postoperative day was also compared. The present study shows that a single oral dose of 150 mg pregabalin given 1 h before surgery attenuated the pressor response to tracheal intubation in adults, but the drug did not show any effect on perioperative opioid consumption and was devoid of side-effects in the given dose.

A comparison of hemodynamic effects of levosimendan and dobutamine in patients undergoing mitral valve repair / replacement for severe mitral stenosis

AIMS AND OBJECTIVES We aimed to compare the hemodynamic effects of levosimendan and dobutamine in patients undergoing mitral valve surgery on cardiopulmonary bypass (CPB). MATERIALS AND METHODS Sixty patients were divided into 2 groups of 30 each. Group-L patients received levosimendan 0.1 μg/kg/min and Group-D patients received dobutamine 5 μg/kg/min while weaning off CPB. Additional inotrope and/or vasoconstrictor were started based on hemodynamic parameters. Hemodynamic data were collected at the end and at 30 minutes after CPB, thereafter at 6, 12, 24, and 36 hours post-CPB. Mean arterial pressure (MAP), central venous pressure (CVP), heart rate (HR), cardiac index (CI), systemic vascular resistance index (SVRI), and lactate levels were measured. RESULTS Group-L showed increased requirement of inotropes and vasoconstrictors. The SVRI, CVP, and MAP were reduced more in Group-L. The CI was low in Group-L in the initial period when compared to Group-D. Later Group-L patients showed a statistically significant increase in CI even after 12 hrs of discontinuation of levosimendan infusion. The HR was increased more in Group-D. Lactate levels, intensive care unit stay, and duration of ventilation were similar in both groups. CONCLUSIONS Levosimendan 0.1 μg/kg/min compared to dobutamine 5 μg/kg/min showed more vasodilation and lesser inotropic activity in patients undergoing mitral valve surgery for mitral stenosis. Levosimendan compared to dobutamine showed a statistically significant increase in CI even after 12 hrs of discontinuation. The requirement of another inotrope or vasopressor was frequent in levosimendan group.

Effect of levosimendan on hemodynamic changes in patients undergoing off-pump coronary artery bypass grafting: A randomized controlled study

AIMS AND OBJECTIVE We tested the hypothesis that use of levosimendan would be associated with better perioperative hemodynamics and cardiac function during off-pump coronary artery bypass grafting (OPCAB) in patients with good left ventricular function. MATERIALS AND METHODS Thirty patients scheduled for OPCAB were randomized in a double-blind manner to receive either levosimendan 0.1 μg/kg/min or placebo after induction of general anesthesia. The hemodynamic variables were measured after induction of anesthesia, at 6 minute after application of tissue stabilizer for the anastomoses of left anterior descending artery, diagonal artery, left circumflex artery, and right coronary artery and at 6, 12, 18, and 24 hours after completion of surgery. RESULTS Compared with placebo group, cardiac index (CI) was significantly higher and systemic vascular resistance index (SVRI) was significantly lower at 6, 12, 18, and 24 hour after surgery in levosimendan group. Norepinephrine was infused in 60% of the patients in the levosimendan group compared to 6.7% in the control group ( P < 0.05). Lactate and mixed venous oxygen saturation were not significantly different between groups. CONCLUSIONS Levosimendan significantly increased CI and decreased SVRI after OPCAB but it did not show any outcome benefit in terms of duration of ventilation and intensive care unit stay.

Scimitar Syndrome: Experience with 6 Patients

Scimitar syndrome is a rare congenital anomaly characterized by anomalous pulmonary venous drainage to the inferior vena cava, causing a left-to-right shunt. Six patients with scimitar syndrome were diagnosed in our hospital between 2002 and 2008. There were 4 girls and 2 boys; 4 < 5 kg in weight, 2 < 8 kg in weight. Scimitar syndrome was suspected in 5 cases because of dextroversion, and diagnosed by color Doppler echocardiography in all 6 when a scimitar vein was detected entering the inferior vena cava. Computed tomography confirmed the diagnosis in all patients. Two patients had horseshoe lung, 2 had a unilobar right lung, 1 had a hypoplastic right lung, and 1 had a hypoplastic right lower lobe. Three patients had severe pulmonary arterial hypertension, 2 had moderate pulmonary arterial hypertension, and one had normal pulmonary arterial pressure. All patients had lower respiratory tract infections, volume loss of the right lung, a normal or hyperinflated left lung, dextroversion of the heart, and scimitar arteries from the descending aorta. Pneumonectomy was performed in 3 patients, lobectomy in 1, ligation of anomalous vessels in 1, and 1 died before surgery.

Early extubation in tetralogy of Fallot patients after complete repair

AIM To document the feasibility of early extubation and to know the effect of age, weight, and post-operative right ventricle/left ventricle ratio in early extubation in intracardiac repair for tetralogy of Fallot. MATERIALS AND METHODS This is a prospective study of 76 consecutive patients undergoing intracardiac repair between January, 2010 and April, 2010. The patients were compared between duration of ventilation with age, weight, and post-operative left ventricle/right ventricle ratio. RESULTS In the age group less than 10 years, 47 patients were extubated within 4 hours and 12 after 4 hours. In the age group of 10-20 years, eight patients were extubated within 4 hours and seven patients after 4 hours. In the more than 20 years category, one patient was extubated within 4 hours and the other after 4 hours. In the weight category less than 10 kilograms, 17 patients were extubated within 4 hours and seven patients after 4 hours. In the 10-20 kilogram category, 27 patients were extubated before 4 hours and four patients after 4 hours. In the more than 20-kilogram category, 12 patients were extubated before 4 hours and nine patients after 4 hours. Where the ratio was less than 0.5, 47 patients were extubated within 4 hours and 14 patients after 4 hours. Where the ratio was greater than 0.5, nine patients were extubated within 4 hours and six patients after 4 hours. CONCLUSION There was no correlation between duration of ventilation with age, weight, and right ventricle/left ventricle ratio. Early extubation in patients after intracardiac repair in tetralogy of Fallot is safe and effective.

Anesthetic considerations for endovascular abdominal aortic aneurysm repair

Aneurysm is defined as a localized and permanent dilatation with an increase in normal diameter by more than 50%. It is more common in males and can affect up to 8% of elderly men. Smoking is the greatest risk factor for abdominal aortic aneurysm (AAA) and other risk factors include hypertension, hyperlipidemia, family history of aneurysms, inflammatory vasculitis, and trauma. Endovascular Aneurysm Repair [EVAR] is a common procedure performed for AAA, because of its minimal invasiveness as compared with open surgical repair. Patients undergoing EVAR have a greater incidence of major co-morbidities and should undergo comprehensive preoperative assessment and optimization within the multidisciplinary settings. In majority of cases, EVAR is extremely well-tolerated. The aim of this article is to outline the Anesthetic considerations related to EVAR.

Early Extubation in Ventricular Septal Defect

Intoduction: The objective of the study to determine the feasibility of early extubation and to know the risk factors for delayed extubation in children who underwent closure of the VSD. Materials and methods: The study was a prospective study done in a tertiary care university hospital. 87 consecutive patients undergoing VSD closure was included in the study. The interventions were to extubate as many patients as feasible within four hours after surgery. Results: 68 of patients were extubated within 4 hours and 19 patients was extubated after 4hours. Mean duration of ventilation among male patients was 160.2 minutes and among female patients was 211.84 minutes. The mean age of the patient was 6.67 years. The mean weight of the patient was 16.85kg. The mean cardiopulmonary bypass time was 53.8 minutes. The mean cross clamp time was 30.11minutes. The mean duration of ventilation in mild PAH was 135.8minutes, moderate PAH was 190 minutes and severe PAH was 238.4minutes. The mean duration of ventilation in perimembranous VSD was 179.56 minutes, sub aortic VSD was 210 minutes and muscular VSD was 162.38 minutes. Conclusions: Cardiopulmonary bypass time and aortic cross clamp time are the two factors which delay the early extubation. Age, weight, sex, severity of pulmonary artery hypertension and type of VSD did not affect early extubation.

Intraoperative anastomotic site detection and assessment of LIMA-to-LAD anastomosis by epicardial ultrasound in off-pump coronary artery bypass grafting--a prospective single-blinded study.

The study was done to detect the optimal site of left anterior descending (LAD) artery for grafting and for the assessment of geometrical and anatomical characteristics of left internal mammary artery (LIMA)-to-LAD artery anastomosis in elective off-pump coronary artery bypass grafting surgery. Fifteen consecutive patients who underwent coronary artery bypass graft (CABG) were included in the study. All the operations were performed by a single surgeon. Epicardial ultrasound probe was placed at the site of grafting for scanning and the site of anastomosis selected. The anticipated target site selected by the surgeon was scanned for patency, size, septal perforator branches, and presence of plaque and calcification. The surgeon identified the LAD artery in 12 patients. In three patients, the LAD artery was not visible. However, with epicardial ultrasound, the LAD artery was identified in all patients. In 6 of 15 patients, the anticipated target anastomotic site was changed to a clear segment either due to the presence of perforators or plaques or calcifications. In all 15 patients, the surgeon scored the anastomosis as good, based on his or her experience independent of the ultrasound image. The anastomotic score by the cardiac anesthesiologist showed 5 anastomoses with satisfactory results and 10 anastomoses with good results. The study demonstrates that epicardial ultrasound scanning with a 10-MHz transducer provides reliable information in choosing the proper anastomotic site and allows proper visualization of LIMA-to-LAD anastomosis. All these measurements are easily obtained without risk of any complications and the method is not time consuming.

Management of tracheomalacia in an infant with Tetralogy of Fallot.

Most infants with tracheomalacia do not need specific therapy as it usually resolves spontaneously by the age of 1-2 years. Severe forms of tracheomalacia characterized by recurrent respiratory infections require active treatment which includes chest physiotherapy, long term intubation or tracheostomy. Aortopexy seems to be the treatment of choice for secondary and even primary forms of severe tracheomalacia. Itentails tracking and suturing the anterior wall of the aorta to the posterior surface of the sternum. Consequently, the anterior wall of the trachea is also pulled forward preventing its collapse. A 3-month-old girl baby who was on ventilatory support for 2 months due to severe tracheomalacia associated with a cyanotic congenital heart disease underwent intracardiac repair and aortopexy along with Lecompte′s procedure as all the conservative measures to wean off the ventilator failed. The baby was extubated on the third post-operative day and the post-operative period was uneventful.