Search PubMed⌕ Search

Biomedical subjects

A Schachner

Publications and source records attributed to A Schachner.

At least 19 recordsLinked to original sources
PubMed2001

Comparison of systemic vasodilators: effects on flow in internal mammary and radial arteries.

BACKGROUND: Spasm is a major concern with the use of arterial conduits in coronary artery bypass surgery (CABG). We evaluated the effect of systemic vasodilators on in vivo radial artery flow compared with internal mammary artery (IMA) flow. METHODS: Fifty patients undergoing primary CABG with a mean age of 69 +/- 5 years enrolled in this study and were randomized to 1 of 5 groups based on the vasodilating agent administered (nitroglycerin, nitroprusside, dobutamine, milrinone, and normal saline as control group). Radial artery and IMA flows, blood pressure, central venous pressure, and heart rate were measured before and 10 minutes after drug administration. RESULTS: Mean arterial pressure decreased significantly after drug administration in both the nitroglycerin (p = 0.007) and nitroprusside (p < 0.001) groups and increased in the dobutamine group (p < 0.001). There were no significant differences between IMA flow or radial flow among the groups before drug administration. A multivariate general linear model was created and revealed drug (specifically nitroglycerin) as the only predictor to increase flow in the IMA (p < 0.001) or the radial artery (p = 0.009). CONCLUSIONS: We conclude that intravenous nitroglycerin causes in vivo vasodilatation of both the IMA and radial artery and is a good systemic vasodilator to be given when harvesting these two conduits.

Aged↗
PubMed2001

Save a child's heart: we can and we should.

BACKGROUND: Congenital heart disease (CHD) causes the death of thousands of children in developing countries. At the Wolfson Medical Center (WMC), a prototype program has been developed to address this issue. METHODS: Since 1996, indigent children have been referred to the program, with the cooperation of partners in developing countries. The project's aims are to (a) train their medical personnel at WMC, (b) travel to participating countries to teach, evaluate patients, operate, and promote the development of local centers, and (c) treat children with CHD, at WMC, who lack a local option for care either due to prohibitive costs or unavailability. The project's personnel are state employees who volunteer to treat additional patients within the framework of their salaries, and community volunteers. RESULTS: The program has seven partner sites in six countries, including two provinces in China (Hebei and Gansu), Ethiopia, Moldova, Nigeria, the Palestinian Authority, and Tanzania. Five physicians and 10 nurses have been trained from five participating countries. Over the past 4 years, 11 teaching trips have been made abroad, and operations have been performed at four partner sites. A total of 386 patients have been operated on-360 at WMC and 26 at other sites. There have been 17 (4.3%) acute deaths. Follow-up is 92% complete with 3 late deaths reported. CONCLUSIONS: Hospital-based regional centers can be created to promote the care of children with CHD in developing countries. Good results and follow-up care can be provided with appropriate planning.

Child↗
PubMed2001

Delayed postoperative paraplegia complicating repair of type A dissection.

We describe the very rare event of delayed transient paraplegia after repair of type A dissection of the aorta and discuss therapeutic options. We also suggest insertion of a spinal catheter as soon as there are signs or symptoms of spinal cord injury to drain spinal fluid and maximize the effect of elevated spinal cord perfusion pressure.

Aortic Dissection↗
PubMed2000

Morbid results of prolonged intubation after coronary artery bypass surgery.

OBJECTIVES: This study evaluated the morbid results of prolonged intubation after coronary artery bypass grafting (CABG). METHODS: Over 30 months, 66 of 1,112 patients undergoing CABG required prolonged intubation. They were matched with 66 patients who did not require prolonged intubation. Preoperative and operative variables were evaluated to determine which would predict prolonged intubation. The postoperative courses were then compared to evaluate the effect of prolonged intubation. The study population was divided into three groups: those who underwent early extubation, but required reintubation (n = 24); those who required initial prolonged intubation, but no reintubation (n = 22); and those who required initial prolonged intubation and reintubation (n = 20). RESULTS: Univariate analysis revealed unstable angina (p = 0.037), elevated creatinine (p = 0.001), reduced FEV(1) (p = 0.019), longer cardiopulmonary bypass time (p = 0.009), and a greater positive fluid balance at 24 h (p = 0.0001) as predictors of postoperative prolonged intubation. Multivariate regression analysis revealed elevated creatinine (p = 0.011), FEV(1) (p = 0.022), and fluid balance (p = 0.001) as predictors of prolonged intubation. The study population had longer ICU and hospital stays (p = 0.0001), with more infectious complications (p = 0.0001) and higher mortality (p = 0. 001). In the subgroups of the study population, patients not requiring reintubation had shorter ICU (p = 0.001) and hospital stays (p = 0.0001), fewer infectious complications (p = 0.0001), and reduced mortality (p = 0.0001). CONCLUSIONS: Patients undergoing CABG with reduced FEV(1), renal failure, and positive fluid balance 24 h postoperatively are at risk for prolonged intubation. Prolonged intubation results in significant acute and midterm morbidity and mortality. Early extubation followed by reintubation further increases morbidity and mortality rates in these patients.

Aged↗
PubMed1999

Distribution of cerebral flow using retrograde versus antegrade cerebral perfusion.

BACKGROUND: This study compared flow to the brain with retrograde and antegrade cerebral perfusion during circulatory arrest. METHODS: Twenty-four rabbits were injected with 5 mCi of technetium-99 macroaggregated albumin, a tracer trapped in the capillaries. Group I (n = 6) were maintained normothermic, and the tracer was injected into the ascending aorta. Group II (n = 6) were maintained normothermic, and underwent cannulation of the superior vena cava (SVC), exsanguination through the aorta, and injection of the tracer into the SVC, which was proximally occluded. In group III (n = 6), the animal was cooled to 25 degrees C. The animal was exsanguinated through the aorta and tracer was injected into the ascending aorta. In group IV (n = 6), animals were cooled to 25 degrees C. The animal was exsanguinated through the ascending aorta and tracer was injected into the SVC. Three animals (group V) were exsanguinated through the ascending aorta and a retrograde venogram of the SVC was performed. Scintigraphy of groups I to IV was carried out on a digital gamma camera. Brain trapping of tracer was graded from 0 to 5, with 0 being no tracer in the brain and 5 being dominant tracer trapping in the brain. RESULTS: Tracer trapping in the brain showed group I, 3.67+/-0.82; group II, 0; group III, 4.67+/-0.41; group IV, 0.17+/-0.41 (p<0.0001). Retrograde venogram of the SVC showed flow into the cerebral veins. CONCLUSIONS: Retrograde flow through the SVC reaches the cerebral venous system. Flow arriving in retrograde fashion does not go through the capillary system.

Animals↗
PubMed1999

Assessment of sternal vascularity with single photon emission computed tomography after harvesting of the internal thoracic artery.

OBJECTIVE: This study prospectively evaluates the effect on sternal vascularity of harvesting the left internal thoracic artery. METHODS: Twenty-four consecutive patients undergoing primary coronary artery bypass grafting were studied. One patient's procedure was altered during the operation, and he was eliminated from the study. The patients were prospectively randomized to receive a skeletonized internal thoracic artery (group I, n = 11) or a pedicled internal thoracic artery (group II, n = 12) graft. Each patient underwent a preoperative technetium 99 methylene diphosphonate bone scan using single photon emission computed tomography. The ratio of the mean counts per pixel on the left side of the sternum was compared with the mean counts per pixel on the right side. Postoperatively, all patients had a second scan, and sternal uptake was compared with the preoperative uptake. RESULTS: No significant differences in preoperative and operative variables were observed between the groups. A statistically significant reduction in blood flow to the left side of the sternum was shown postoperatively in group II compared with group I (0.61 +/- 0.11 vs 0.85 +/- 0.09; P <.001). Multivariable logistic regression analysis of preoperative and operative variables revealed only a pedicled left internal thoracic artery to be associated with a 20% or more reduction in left-to-right sternal activity ratio (odds ratio, 100; 70% confidence limits, 22-465; P =.002). CONCLUSION: A pedicled left internal thoracic artery graft to the left anterior descending artery reduces blood flow to the left side of the sternum during the acute postoperative period. This does not occur when the left internal thoracic artery is skeletonized.

Aged↗
PubMed1998

Phrenic nerve injury after coronary artery bypass grafting: will it go away?

BACKGROUND: Phrenic nerve injury after coronary artery bypass grafting resolves in most cases. The purpose of this study was to analyze the causes and effects of persistent phrenic nerve injury after coronary artery bypass grafting. METHODS: From a registry of patients with chronic obstructive pulmonary disease who underwent coronary artery bypass grafting, 64 patients were identified who experienced phrenic nerve injury during their operation. Fifteen patients either died during follow-up (n = 9) or were lost to follow-up (n = 6). At the last follow-up visit, all the patients underwent an ultrasound evaluation of the diaphragm and were divided into those who had persistent dysfunction (group I) and those who had normal function (group II). The groups were compared for preoperative and operative risk factors, acute and midterm postoperative results, and quality of life at last follow-up. RESULTS: There were 13 patients in group I and 36 in group II. There were no significant differences in preoperative and operative risk factors between the groups. The length of hospitalization was similar for both groups (9.2 +/- 4.5 versus 8.5 +/- 3.3 days, respectively; p = 0.77). More patients in group I required reintubation (23% versus 14%, respectively; p = 0.04). The mean duration of follow-up was 32.7 +/- 9.2 months. At that time, both groups suffered a reduction of forced expiratory volume in 1 second compared with preoperative values. Group I had a greater reduction in forced expiratory volume in 1 second (p = 0.05). There were a total of 125 postoperative readmissions during the follow-up period, 36 in group I and 89 in group II. There were more admissions because of pulmonary problems in group I (85% versus 53%; p = 0.04). Of the 49 patients, 21 perceived a decline in quality of life after operation. More patients in group I (46% versus 22%; p = 0.05) complained of this decrease. CONCLUSIONS: A significant number of patients who incur phrenic nerve injury after coronary artery bypass grafting have persistent phrenic nerve injury. Patients with persistent phrenic nerve injury have increased acute and midterm morbidity after operation, as well as reduced quality of life.

Aged↗
PubMed1998

Non-invasive measurement of cardiac output during coronary artery bypass grafting.

OBJECTIVE: A new device, using whole body bioresistance measurements and a new equation for calculating stroke volume has been developed. Using this equation, an attempt was made to correlate whole body bioresistance cardiac output with thermodilution cardiac output in patients undergoing coronary artery bypass grafting. METHODS: Thirty-one adults undergoing elective coronary artery bypass grafting were studied prospectively. Simultaneous paired cardiac output measurements by whole body bioresistance and thermodilution were made at five time points during coronary artery bypass grafting: in anesthetized patients before incision (T1), after sternotomy (T2), after opening the pericardium (T3), ten min post bypass (T4), and in the intensive care unit (T5). The patients had a mean of three thermodilution cardiac outputs compared with a mean of three bioimpedance measurements at each time point. The bias and precision between the methods were calculated. RESULTS: There was good correlation between bioresistance cardiac output (nCO) and thermodilution cardiac output (ThCO) measurements in both groups for all recorded times. The patients' mean ThCO and nCO, as well as bias and precision between methods were calculated. Mean ThCO ranged between 4.14 and 5.06 l/min; mean nCO ranged between 4.12 and 4.97 l/ min. Bias calculations ranged between -0.072 and 0.104 l/min. Precision (2 SD) calculations ranged between 0.873 and 1.228 l/min for 95% confidence intervals. Pearson's correlation ranged from 0.919 to 0.938. CONCLUSIONS: Cardiac output measured with the new device correlates well with the thermodilution measurements of cardiac output during and immediately following coronary artery bypass grafting. The overall agreement between the two methods was good. The new device is an accurate non-invasive method of measuring cardiac output during coronary artery bypass grafting.

Aged↗
PubMed1997

Phrenic nerve injury after coronary artery grafting: is it always benign?

BACKGROUND: The purpose of this study was to evaluate the effect of phrenic nerve injury (PNI) occurring during coronary artery bypass grafting in patients with major chronic obstructive pulmonary disease (COPD). METHODS: Over a 42-month period, 1,303 patients underwent primary coronary artery bypass grafting. Sixty-seven (5.14%) had major COPD, and 29 (43.3%) of these 67 sustained PNI (group I). These patients were matched for age and ejection fraction with 29 CABG patients with COPD but without PNI (group II), 29 patients without COPD but with PNI (group III), and 29 patients with neither COPD nor PNI (group IV). The groups were compared on the basis of preoperative and operative factors and immediate and midterm morbidity and mortality. RESULTS: There were no significant differences between the groups with respect to hypertension, diabetes, ejection fraction, number of grafts, internal mammary artery use, cardiopulmonary bypass time, and ischemic time. Postoperatively, group I had a longer total hospitalization (group I, 11.7 days; group II, 7.8 days; group III, 7.8 days; and group IV, 6 days; p = 0.0001) and stay in the intensive care unit (I, 3.6 days; II, 2.2 days; III, 2.1 days; and IV, 1.2 days; p = 0.0023). More patients in group I required reintubation (I, 37.9%; II, 3.4%; III, 6.9%; and IV, 0%; p < 0.0001). Mean follow-up was 32.8 months (range, 7 to 48 months). Group I had more hospital readmissions (I, 78; II, 50; III, 61; and IV, 28; p < 0.007) and lower cumulative survival (I, 60.6%; II, 93%; III, 96.8%; and IV, 100%; p < 0.0015) compared with the other groups. CONCLUSIONS: In patients with COPD, PNI during coronary artery bypass grafting has a major negative impact on immediate and midterm results.

Aged↗
PubMed1996

Effect of systemic vasodilators on internal mammary flow during coronary bypass grafting.

BACKGROUND: The effect of vasodilators on acute flow in the internal mammary (IMA) is unclear. Topical vasodilators show no effect on acute flow when the distal segment of the IMA is resected. The purpose of this study was to evaluate the effect of systemic vasodilators when this segment is resected. METHODS: We studied 60 patients with proximal anterior descending coronary artery lesions in whom the left IMA was harvested for grafting to the left anterior descending coronary artery. The patients were divided into six groups (n = 10), based on which of the following agents were studied: normal saline solution, nitroglycerin, nitroprusside, dobutamine, dopexamine, and amrinone. After harvesting, the IMA was trimmed as proximally as possible (and at least 3 cm proximal to the bifurcation), and free flow was measured before any pharmacologic intervention (flow 1). Systemic infusion of one of the six agents commenced. A mean of 17 +/- 3.4 minutes after infusion began, with a comparable cardiac index, a second measurement of IMA flow was taken (flow 2). Hemodynamic measurements for each flow, including blood pressure, heart rate, and cardiac output, were taken. RESULTS: A significant increase in IMA flow was noted for those patients receiving nitroglycerin (93.5 versus 106.8 mL/min; p = 0.025), and a significant decrease in flow was noted for those receiving nitroprusside (91.0 versus 78.2 mL/min; p = 0.042). The effects remained significant when corrected for cardiac index and compared with the normal saline solution group. No other systemic agents tested significantly affected the IMA flow (dobutamine, 83.8 versus 85.0 mL/min; dopexamine, 101.8 versus 91.4 mL/min; amrinone, 75.4 versus 79 mL/min; normal saline solution, 85.8 versus 84.6 mL/min). CONCLUSIONS: Resection of the distal segment of the IMA and the use of intravenous nitroglycerin optimizes the flow in IMA grafts.

Amrinone↗
PubMed1996

Myocardial bridging: surgical technique and operative results.

We report a case of a 37-year-old symptomatic male with anterior myocardial ischemia. Coronary angiography demonstrated systolic obstruction of the midportion of the left anterior descending coronary artery due to myocardial bridging. The patient was treated with a supra-arterial myotomy. Two years postoperatively, the patient is without evidence of myocardial ischemia. Angiography, 2 years postoperatively, shows no evidence of systolic narrowing of the left anterior descending coronary artery.

Adult↗
PubMed1995

Effect of topical vasodilators on internal mammary arteries.

The internal mammary artery (IMA) is the conduit of choice for grafting the left anterior descending artery. However, arterial spasm and reduced early flow has been a cause of postoperative morbidity. The purpose of this study is to evaluate the effect of vasodilators on IMA flow. Fifty patients who had the IMA harvested in preparation for bypass grafting were studied. The IMA was mobilized from the subclavian vein to below the bifurcation of the IMA. The artery was prepared for grafting at least 3 cm proximal to the bifurcation. The IMA was allowed to bleed freely, and flow was determined (flow 1). The patients were divided into five groups: group I (n = 10) had 10 mL of saline solution applied topically to the IMA; group II had topical papaverine (5 mg/10 mL normal saline solution) applied to the IMA; group III had nitroglycerin (5 mg/10 mL normal saline solution) applied to the IMA, group IV had sodium nitroprusside (2.5 mg/10 mL) applied to the pedicle, and group V had 5 mL of papaverine mixed in 5 mL of saline solution injected into the periarterial tissues of the IMA pedicle. Before cardiopulmonary bypass, the flows were remeasured (flow 2). With each measurement, hemodynamic parameters were recorded. The time between measurements was recorded. There was no difference in blood pressure or pulse at the time of measurement.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Topical↗
PubMed1995

Interaction of thyroid hormone and heparin in postischemic myocardial recovery.

BACKGROUND: Triiodothyronine (T3) administration can improve postischemic myocardial recovery. Heparin can interfere with cellular binding of T3. Introduction of heparin into an isolated heart model may interfere with this effect. METHODS: Four groups of 8 rat hearts were placed on a modified Langendorff apparatus. All groups underwent 15 minutes of perfusion with modified Krebs-Henseleit solution (KH), followed by 20 minutes of normothermic global ischemia and 30 minutes of reperfusion. Group I underwent reperfusion with KH. Group II underwent reperfusion with KH and 1 x 10(-6) mol/L of T3. In group III, hearts underwent preischemic perfusion with heparinized KH (1,000 U/L) and reperfusion with KH containing 1 x 10(-6) mol/L of T3 and 1,000 U/L of heparin. In group IV, rats were given heparin at 2,000 IU/kg 30 minutes before sacrifice, and isolated hearts were reperfused with KH and 1 x 10(-6) mol/L of T3. A latex balloon in the left ventricle monitored hemodynamic variables. RESULTS: Left ventricular developed pressure throughout postischemic reperfusion was greater in all the groups receiving T3 when compared with group I. Group II showed significantly greater recovery than either group III (p < 0.05) or group IV (p < 0.05). CONCLUSIONS: Addition of T3 to the reperfusate enhances postischemic myocardial recovery in the isolated heart model, whereas addition of heparin reduces this effect.

Animals↗
PubMed1995

Chronic obstructive pulmonary disease in patients undergoing coronary artery bypass grafting.

The purpose of this study was to evaluate the effect of chronic obstructive pulmonary disease on patients undergoing coronary artery bypass grafting. Between June 1991 and June 1993, 651 patients underwent coronary artery bypass grafting: 37 patients (group I) had significant chronic obstructive pulmonary disease. These patients were compared with 37 matched control subjects (group II). Comparison of the groups was made with regard to postoperative morbidity and mortality. Quality of life of survivors was compared at the last follow-up. More patients in group I had preoperative arrhythmias (8 versus 1, p = 0.014). Group I patients had lower values of forced expiratory volume in 1 second (1.366 +/- 0.032 L versus 2.335 +/- 0.49 L, p < 0.0001), lower oxygen tension (63.5 +/- 8.2 versus 79.1 +/- 13.4 mm Hg, p = 0.001), and higher carbon dioxide tension (44.8 +/- 6.5 mm Hg versus 39.7 +/- 3.6 mm Hg, p = 0.001). After operation patients in group I had a longer hospital stay (8.1 +/- 3.6 days versus 6.6 +/- 1.7 days, p = 0.0236) and longer intensive care unit stay (2.64 +/- 0.9 days versus 1.23 +/- 0.49 days, p = 0.0001). More patients in group I required prolonged intubation (7 versus 1, p = 0.0278) and reintubation (5 versus 1, p = 0.088). More patients in group I had significant arrhythmias (27 versus 9, p < 0.0001). During a 16-month follow-up period, five patients in group I died, whereas none in group II died (p = 0.0271). Four deaths were related to arrhythmias. More group I patients were not functionally improved by the operation (17 versus 3, p = 0.0056). The results of coronary artery bypass grafting in patients with significant chronic obstructive pulmonary disease were not favorable in midterm follow-up. A major cause for morbidity and mortality was postoperative arrhythmias.

Aged↗
PubMed1993

Anatomic considerations in closed transatrial cannulation of the coronary sinus.

Successful closed transatrial coronary sinus cannulation is dependent on a proper catheter insertion site and proper catheter direction. Accurate anatomic landmarks are described to provide a reproducible cannulation site and catheter direction. This results in consistent successful cannulation of the coronary sinus.

Cadaver↗
PubMed1990

Rapid percutaneous tracheostomy.

We describe a new method of performing percutaneous tracheostomy rapidly and safely using a specialized instrument kit. The technique permits the safe insertion of a full-sized 7.0 (ID) or 7.5 mm (ID) cuffed cannula into the trachea within 1-2 min, through the membranous second intercartilagenous space. Animal studies have demonstrated a superior healing process compared to that seen after conventional tracheostomy techniques.

Animals↗