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Biomedical subjects

Y Mehta

Publications and source records attributed to Y Mehta.

At least 19 recordsLinked to original sources
PubMed2001

Comparison of continuous thoracic epidural and paravertebral blocks for postoperative analgesia after minimally invasive direct coronary artery bypass surgery.

OBJECTIVE: To compare continuous thoracic epidural analgesia (TEA) and paravertebral block (PVB) for postoperative analgesia in patients undergoing minimally invasive direct coronary artery bypass (MIDCAB) surgery for quality of analgesia, complications, compliance to chest physiotherapy, hemodynamics, and respiratory effects. DESIGN: Prospective, randomized study. SETTING: Specialty research hospital. PARTICIPANTS: Forty-one consenting patients undergoing MIDCAB surgery. INTERVENTIONS: Patients in the TEA group had an epidural catheter inserted at the T4-5 interspace, whereas patients in the PVB group had a catheter inserted in the paravertebral space on the left side at the T4-5 level. MEASUREMENTS AND MAIN RESULTS: Parameters evaluated included visual analog scale pain scores at rest and while coughing, supplemental analgesic requirement, complications, hemodynamics, and respiratory parameters. Measurements were made at 2-hour intervals for 12 hours beginning at 10 minutes after endotracheal extubation. There was no statistically significant difference in visual analog scale scores and requirement of supplemental analgesia between the 2 groups. Cardiac index at 4 hours and 6 hours was significantly higher in the TEA group. Patients in the PVB group had significantly lower respiratory rates at 8, 10, and 12 hours. All other parameters were comparable. In 1 patient, the epidural space could not be catheterized. One patient in the TEA group had transient hypotension, and 1 patient complained of backache at the site of the epidural catheter insertion. CONCLUSION: PVB is as effective as TEA for postoperative analgesia after MIDCAB surgery. PVB is technically easier than TEA and may be safer than TEA because no complications were seen in the PVB group.

Analgesia, Epidural↗
PubMed2000

Off-pump redo coronary artery bypass grafting.

BACKGROUND: Conventional redo coronary artery bypass grafting is associated with significant morbidity. The danger of reoperation is mainly in reopening the sternum and in the manipulation of the heart and the old grafts. Therefore, off-pump redo coronary artery bypass grafting with a patient-specific approach in selected cases seems an ideal technique. METHODS: Between October 1995 to September 1999, 50 patients with mean age of 61.8+/-8 years underwent reoperative coronary artery bypass grafting without cardiopulmonary bypass. Isolated left internal mammary artery (LIMA) to left anterior descending artery (LAD) anastomosis was carried out in 25 cases through left anterior minithoracotomy. In 1 patient LIMA was grafted on a previous vein graft to LAD, which was critically stenosed proximally but distal anastomosis was patent. In another case LIMA was grafted to Ramus intermedius branch. Midsternotomy approach was used to carry out LAD and right coronary artery grafting in 21 cases. In 2 patients a posterolateral thoracotomy approach was used to bypass obtuse marginal branches without cardiopulmonary bypass; in these cases proximal anastomosis was performed on the descending aorta. RESULTS: Mortality rate was 4% (2 deaths). Two patients sustained perioperative myocardial infarction. No patient was reexplored for hemorrhage and 38 patients did not require homologous blood transfusion. Sixteen patients underwent check angiogram and all of them were found to have patent redo grafts. Cardiac recovery room stay was 22+/-7 hours and hospital stay 5+/-2 days. CONCLUSIONS: In selected patients, reoperative coronary artery bypass grafting can be performed without cardiopulmonary bypass with a low perioperative morbidity and mortality and satisfactory graft patency.

Coronary Artery Bypass↗
PubMed2000

Total intravenous anesthesia with ketamine for pediatric interventional cardiac procedures.

OBJECTIVE: To evaluate the safety and efficacy of ketamine in pediatric patients undergoing interventional cardiac procedures. DESIGN: A retrospective clinical study. SETTING: A single, tertiary referral center. PARTICIPANTS: Patients (n = 107) undergoing interventional cardiac procedures between July 1996 and July 1998. INTERVENTIONS: Each patient received a bolus of ketamine, 1 mg/kg intravenously, followed by an infusion of 50 to 75 microg/kg/min for the duration of the procedure. MEASUREMENTS AND MAIN RESULTS: Hemodynamic and respiratory parameters were noted. All patients were breathing spontaneously. Average infusion dose of ketamine was 51.40+/-3.54 microg/kg/min (mean +/- standard deviation). Increases in heart rate and mean arterial pressure by more than 20% from baseline values were seen in 10 and 9 patients, respectively. Transient apnea and excessive salivation were seen in two patients each. Excessive movement of extremities was seen in six patients. There were no episodes of unpleasant dreams or hallucinations. There were two deaths (1.9%) related to the interventional procedures. CONCLUSION: The technique described is a simple, safe, and effective method for anesthetizing children in the cardiac catheterization laboratory for interventional procedures.

Adolescent↗
PubMed2000

Comparison of ministernotomy with minithoracotomy regarding postoperative pain and internal mammary artery characteristics.

PURPOSE: This prospective clinical study focuses on postoperative pain and internal mammary artery (IMA) characteristics after ministernotomy versus left anterior minithoracotomy. METHOD: Patients were studied in two groups. Group A consisted of 267 consecutive single vessel (IMA to left anterior descending artery (LAD)) minimally invasive direct coronary artery bypass (MIDCAB) patients using ministernotomy from the tip of the xiphoid to the fourth intercostal space. Group B consisted of the same number of MIDCAB patients operated on through anterolateral minithoracotomy. Pain was graduated using the visual analog scale (VAS). Internal mammary artery (IMA) characteristics were compared in both the groups. RESULTS: Postoperative pain was not significant statistically on postop day (POD) 1 in either of the groups (p = 0.07). From POD 2 onwards Group A patients had less pain than Group B patients (p < 0.05), and the pain medication requirement from POD 2 onwards was less in Group A than in Group B. Length of harvested IMA was 15.6 +/- 2.1 cm in Group A as compared to 10.4 +/- 2.2 cm in Group B (p < 0.05). Free flow of IMA in group A was 56 +/- 16 ml/min., whereas in Group B the flow was 50 +/- 14 ml/min. (p = 0.04). CONCLUSION: Compared to patients undergoing MIDCAB using ministernotomy, anterolateral minithoracotomy patients suffer more pain from POD 2 onwards and their postoperative pain medication requirement is also higher. Length and free flow of IMA is better in patients operated on for MIDCAB using ministernotomy. Thus, ministernotomy is a better approach than minithoracotomy in terms of postoperative pain and IMA characteristics for single-vessel MIDCAB patients.

Adult↗
PubMed1999

TWIK-2, a new weak inward rectifying member of the tandem pore domain potassium channel family.

Potassium channels are found in all mammalian cell types, and they perform many distinct functions in both excitable and non-excitable cells. These functions are subserved by several different families of potassium channels distinguishable by primary sequence features as well as by physiological characteristics. Of these families, the tandem pore domain potassium channels are a new and distinct class, primarily distinguished by the presence of two pore-forming domains within a single polypeptide chain. We have cloned a new member of this family, TWIK-2, from a human brain cDNA library. Primary sequence analysis of TWIK-2 shows that it is most closely related to TWIK-1, especially in the pore-forming domains. Northern blot analysis reveals the expression of TWIK-2 in all human tissues assayed except skeletal muscle. Human TWIK-2 expressed heterologously in Xenopus oocytes is a non-inactivating weak inward rectifier with channel properties similar to TWIK-1. Pharmacologically, TWIK-2 channels are distinct from TWIK-1 channels in their response to quinidine, quinine, and barium. TWIK-2 is inhibited by intracellular, but not extracellular, acidification. This new clone reveals the existence of a subfamily in the tandem pore domain potassium channel family with weak inward rectification properties.

Amino Acid Sequence↗
PubMed1999

Minimally invasive mitral valve surgery through right anterolateral minithoracotomy.

BACKGROUND: This study evaluates the feasibility of minimally invasive mitral valve surgery. The aim of the study was to minimize surgical access to achieve better cosmetic results, less postoperative discomfort, and faster recovery. METHODS: From September 1997 to October 1998, 76 patients underwent mitral valve surgery through a right anterolateral minithoracotomy at the fourth intercostal space. The mitral valve was either repaired (n = 21) or replaced (n = 55). In all cases, open femoral artery-femoral vein cannulation was used for cardiopulmonary bypass. In 27 cases, an endoluminal aortic clamp was used, but in 49 cases, the aorta was cross-clamped with a transthoracic, sliding-rod-design clamp. RESULTS: There were no approach-related limitations to surgical intervention. Intraoperative transesophageal echocardiography revealed excellent results after valve repair and no paravalvular leak in any patient after mitral valve replacement. Mean duration of intensive care and postoperative hospital stay was 32+/-5.2 hours and 7+/-1.1 days, respectively. There were no major complications related to femoral vessel cannulation. In 1 patient, transient neurological problems developed, with subsequent complete recovery. There was one hospital mortality (85-year-old male patient died of upper GI bleeding). CONCLUSIONS: Minimally invasive port access mitral valve surgery can accelerate recovery and decrease pain, while maintaining overall surgical efficacy. It also provides better cosmetic results to our patients, and now it has become our standard approach for isolated mitral valve surgery.

Adult↗
PubMed1999

Lumbar versus thoracic epidural buprenorphine for postoperative analgesia following coronary artery bypass graft surgery.

BACKGROUND: Thoracic epidural analgesia (TEA) is reported to provide effective analgesia following cardiac surgery. We compared the effect of buprenorphine (BN) through the lumbar and thoracic epidural routes for postoperative analgesia following coronary artery bypass graft surgery (CABG). METHODS: Forty patients with normal left ventricular ejection fraction scheduled for CABG were randomly divided into two groups, the TEA group (n = 19) and the lumbar epidural analgesia (LEA) group (n = 20). For postoperative pain relief they received epidural BN 0.15 mg at the first demand for pain relief following extubation. A top-up dose of BN 0.15 mg was administered in cases where visual analogue scale (VAS) score was > 3 at 1 h after first dose. Subsequent breakthrough pain was treated with 30 mg intramuscular ketorolac tromethamine (ketorolac). Pain assessed by VAS score on a 0-10 scale, respiratory rate, FEV1, FVC, mean arterial blood pressure, cardiac index, PaO2 and PaCO2 were measured at frequent intervals. Side effects of epidural opioids were noted. RESULTS: Both groups were comparable in demographic characteristics, had similar VAS scores from 1 to 24 h postoperatively, required similar amounts of intramuscular ketorolac for break-through pain and had comparable pulmonary functions and side effects. CONCLUSION: This study shows that BN by the lumbar epidural route for analgesia after CABG compares favourably with the same drug through the thoracic route in terms of quality of analgesia and incidence of side effects.

Adult↗
PubMed1998

Transmyocardial laser as an adjunct to minimally invasive CABG for complete myocardial revascularization.

BACKGROUND: To achieve complete myocardial revascularization in patients with diffuse coronary artery disease and patients at high risk if they undergo cardiopulmonary bypass such as severe systemic disease or diffuse arteriosclerosis of the aorta, we have adopted the technique of combining direct coronary artery bypass grafting without cardiopulmonary bypass with transmyocardial laser revascularization. METHODS: From April 1995 to September 1997 this technique was used in 77 patients. Ages ranged from 37 to 85 years with a mean of 56 +/- 17 years. Diffuse coronary artery lesions were present in 46 patients, 10 had severely deranged renal function, 7 had diffuse carotid artery lesions, and 7 had aortic arch atheromas. Liver dysfunction was present in 4 patients and severe obstructive airway disease in 3. The mean left ventricular ejection fraction was 0.45 +/- 0.05. Midsternotomy approach was used in 65 patients and anterior minithoracotomy in 12. Direct coronary artery bypass grafting without cardiopulmonary bypass was done to the left anterior descending coronary artery or right coronary artery or both. Transmyocardial laser revascularization using a 1,000-W CO2 laser machine was performed on the areas supplied by ungraftable coronary arteries or even in graftable distal targets in the posterolateral or inferior wall in patients who were at high risk if they underwent cardiopulmonary bypass. RESULTS: The mean number of vessels bypassed was 1.12. One patient died of intractable ventricular arrhythmia in the early postoperative phase. Mean follow-up was 16.6 months. At 12 months 89% of the patients were angina free. Metabolic stress test demonstrated an average increase in exercise tolerance from 5.2 at baseline to 9.7 minutes at 12 months. Myocardial thallium scanning done at 3-, 6-, and 12-month intervals postoperatively revealed that myocardial perfusion in grafted segments had an exponential trend of improvement, and perfusion in transmyocardial laser revascularization segments showed a linear trend in the same period with a total gain of 28.4%. CONCLUSIONS: Transmyocardial laser revascularization is an excellent adjunct to minimally invasive coronary artery bypass grafting to achieve complete myocardial revascularization in patients with graftable vessels in the anterior wall and ungraftable vessels in the posterior and inferior wall. This achieves complete myocardial revascularization without compromising safety in patients who are at high risk if they undergo cardiopulmonary bypass. Minimal morbidity and mortality in the present series revealed that this procedure is safe, and postoperative follow-up of these patients showed significant functional improvement as well as an improvement in myocardial perfusion scan.

Adult↗
PubMed1998

Mammary coronary artery anastomosis without cardiopulmonary bypass through minithoracotomy: one year clinical experience.

OBJECTIVE: The recent concept of minimally invasive coronary artery surgery in selected patients has dramatically affected surgical management of coronary artery disease. We explored the possibility of coronary artery bypass grafting of anterior coronary arteries with in situ internal mammary artery through a limited anterior thoracotomy on beating heart. METHOD: Minithoracotomy and direct coronary artery surgery without cardiopulmonary bypass (CPB) was attempted in 116 patients. The procedure was completed in 108 cases while in eight cases minithoracotomy was converted to mid sternotomy. In 107 cases, left internal mammary artery (LIMA) to left anterior descending (LAD) coronary artery anastomosis was done through left anterior minithoracotomy and in one case LIMA to LAD and right internal mammary artery (RIMA) to right coronary artery (RCA) anastomosis was done through bilateral minithoracotomy. Left anterior minithoracotomy through 4th intercostal space and right anterior minithoracotomy through 5th intercostal space was used for left and right internal mammary artery dissection respectively. With this approach 4-8 cm length of mammary artery was easily dissected. Mammary coronary artery anastomosis were performed on a beating heart without CPB through window pericardiotomy. Two patients also underwent left carotid endarterectomy along with LIMA to LAD anastomosis. In two patients complementary percutaneous transluminal coronary angioplasty (PTCA) to circumflex artery was done 5 days after minithoracotomy and LIMA to LAD anastomosis. RESULTS: Forty-two patients were extubated in the operating room and 66 in the intensive care unit 2-10 h after surgery. Blood transfusion was used in one case who was reexplored for postoperative bleeding due to a displaced hemoclip from the internal mammary artery branch. None of these patients required inotropic support. Postoperative predischarge check angiogram in 53 cases revealed adequate mammary coronary flow in 51 cases, the remaining two had anastomotic problems, one was subjected to PTCA and the other for redo coronary bypass grafting through mid sternotomy. Doppler flow assessment of anastomosis was done in 102 cases, of which two showed problems which was confirmed on check angiography. One-hundred and six patients are in our regular follow-up (mean follow-up 10+/-1.5 months), 98 of them are in functional class I. CONCLUSION: In our experience mammary coronary artery anastomosis without CPB through minithoracotomy is a safe, simple and minimally invasive procedure. Favorable cost/benefit ratio, has been achieved due to no early/late mortality and minimal early morbidity. Postoperative check angiogram and Doppler flow study revealed excellent mid term results.

Cardiopulmonary Bypass↗
PubMed1998

A comparative evaluation of intrapleural and thoracic epidural analgesia for postoperative pain relief after minimally invasive direct coronary artery bypass surgery.

OBJECTIVE: To compare the efficacy of thoracic epidural analgesia (TEA) and intrapleural analgesia (IPA) after minimally invasive direct coronary artery bypass (MIDCAB) surgery with regard to quality of analgesia and complications. DESIGN: A prospective, randomized study. SETTING: A specialty research hospital. PARTICIPANTS: Fifty consenting adults scheduled for MIDCAB surgery. INTERVENTIONS: All patients underwent elective MIDCAB surgery. Patients in the TEA group (n=25) had an epidural catheter inserted in the fourth to fifth thoracic interspace and those in the IPA group (n=25) had an intrapleural catheter inserted in the sixth to seventh intercostal space intraoperatively under vision. MEASUREMENTS AND MAIN RESULTS: Parameters evaluated after administration of bupivacaine (8 mL of 0.25% in the TEA group and 20 mL of 0.25% in the IPA group) on first demand included visual analog scale (VAS) pain scores, cardiovascular and respiratory (clinical, blood gases) function, wakefulness, supplemental analgesic requirement, and complications. Measurements were made at 2-hour intervals for the next 12 hours. VAS scores were significantly lower at 2, 6, 8, and 12 hours in the IPA group (TEA = 3.5, 4.5, 4.9, 4.6; IPA = 2.2, 3.6, 3.5, 3.7). There were no significant differences in hemodynamic or respiratory parameters or postoperative requirement for supplemental analgesia. In the TEA group, three patients had catheter migration and four had severe backache. CONCLUSION: IPA is a safe and effective technique for postoperative analgesia after MIDCAB surgery and has a low complication rate compared with TEA. Careful positioning, chest tube clamping, and anchoring of the catheter are mandatory for IPA to be effective.

Analgesia, Epidural↗