Search PubMed⌕ Search

Biomedical subjects

R D Weisel

Publications and source records attributed to R D Weisel.

At least 217 records · Page 12Linked to original sources
PubMed1979

Sleeve lobectomy for carcinoma of the lung.

Sleeve lobectomy for non-oat cell carcinoma involving a major bronchus preserves functioning lung tissue and, in carefully selected patients, provides long-term survival comparable to pneumonectomy. Seventy patients underwent sleeve lobectomy between 1967 and 1978. Twenty-seven patients were considered compromised (Group I) because they had severe respiratory impairment which contraindicated pneumonectomy. Forty-three patients were considered uncompromised (Group 2) and underwent elective sleeve lobectomy. Seventy patients with a similar non-oat cell carcinoma involving the proximal bronchi underwent pneumonectomy (Group 3) during this period. Perioperative complications occurred more frequently in Group 1 (59%) than in Group 2 (21%) or Group 3 (23%). Both periopeative mortality rate and the incidence of bronchial disruption (bronchovascular and bronchopleural fistulas) were higher in Group I (19% and 22%) than in Group 2 (9% and 5%) or Group 3 (3% and 7%). Survival depended primarily on the surgeon's ability to perform a complete resection of the tumor. An incomplete resection resulted when tumor was found in the highest lymph node or in the last bronchial resection margin when paraffin sections were reviewed. The 5 year survival rate was 18% for compromised patients (Group 1) who underwent complete resection, and there were no survivors among patients undergoing incomplete resections. Uncompromised patients ( Group 2) had a 5 year survival rate of36% with complete and 12% with incomplete resections. Pneumonectomy patients (Group 3) had a 64% 5 year survival rate with a complete resection and 16% with an incomplete resection. The stage of the disease at the time of operation had a profound effect on the survivail. There was no difference inthe 5 and 8 year survival rates between uncompromised patients undergoing sleeve resection ( Group 2) and patients undergoing peneumonectomy (Group 3) for comparable stage of their disease. A careful pre- and postoperative functional assessment revealed that pulmonary performance was improved in 44% of Group 1, 63% of Group 2, and only 14% of Group 3 patients. Patients wiht impaired pulmonary reserve underwent sleeve lobectomy with an adequate disease-free interval when complete tumor excision was possible. Uncompromised patients whose extensive disease required incomplete resection had palliation by sleeve lobectomy equivalent to that by pneumonectomy. When complete t-mor resection was possible, patients with uncompromised pulmonary reserve had a perioperative complication rate and long-term survival equivalent to that of pneumonectomy while preserving pulmonary parenchyma, which permitted an improvement in postoperative pulmonary performance.

Adenocarcinoma↗
PubMed1978

Transfusion of 2,3 DPG-enriched red blood cells to improve cardiac function.

Attempts were made to enhance oxygen availability in patients undergoing coronary artery bypass operations by transfusing red blood cells enriched in 2,3 diphosphoglycerate (2,3 DPG) to 150% of normal. In this study of 22 patients, 11 received red blood cells with high 2,3 DPG levels and 11 received red blood cells with 70% of normal 2,3 DPG levels (control). Immediately following cardiopulmonary bypass the 11 patients who received high 2,3 DPG red blood cells had a P50 value of 31.6 mm Hg; the value in control patients was 28.3 mm Hg (p less than 0.05). Oxygen consumption values were 135 and 106 ml/min/m2, respectively (p less than 0.05). Mixed venous oxygen tensions were similar in the two groups, but the arteriovenous content difference was higher in the high 2,3 DPG group (p less than 0.05). Cardiac indices increased significantly in response to a fluid load in the high 2,3 DPG group compared with controls at comparable filling pressures. We believe the improved myocardial performance in response to a fluid challenge is a result of increased oxygen availability.

Blood Transfusion↗
PubMed1978

Changing patterns of intra-aortic balloon pump assistance.

Intra-aortic balloon pump assistance (IABPA) for cardiogenic shock is well established. The response to balloon pumping and patient survival are better after low output from cardiotomy than after myocardial infarction. Elective use of IABPA preoperatively allows an extra margin of safety for patients with acute coronary insufficiency, significant left main coronary artery stenosis, or depressed left ventricular function. However, advances in monitoring techniques during the induction of anesthesia and weaning from cardiopulmonary bypass support, as well as improved methods for myocardial preservation, have reduced the requirements for elective IABPA. Current indications for preoperative IABPA include: patients with acute coronary insufficiency who are totally unresponsive to full medical management and who continue to have pain and electrocardiographic changes at rest, and patients with serious left main coronary artery stenosis who also have acute coronary insufficiency or depressed left ventricular function. The survival of patients with valvular heart disease and left ventricular dysfunction is not improved with preoperative IABPA, while most patients with depressed left ventricular function from coronary artery disease may now undergo revascularization uneventfully, although inevitably some will still require postoperative IABPA.

Assisted Circulation↗
PubMed1978

Optimal myocardial protection.

The low mortality and perioperative infarction rates for aortocoronary bypass (ACB) make them unsuitable for evaluating the adequacy of myocardial protection. Enzymatic and functional measurements were found to be sensitive and specific indicators of myocardial injury. A prospective concurrent study of 78 patients undergoing triple ACB was conducted to evaluate the effectiveness of three popular methods of myocardial protection. Group I (32 patients) had a single dose of cold (4 degrees C) potassium cardioplegic (CPC) solution infused inducing a mean myocardial temperature (MMT) of 31 +/- 4 degrees C/min. Group II (23 patients) had multiple doses of CPC solution 8nducing a MMT of 22 +/- 2 degrees C/min. Group III (23 patients) had intermittent anoxic arrest at a MMT of 28 +/- 1 degrees C. The groups were not randomized but had comparable clinical symptoms and catheterization findings. Serial measurements of cardiac specific creatine kinase (CK-MB) revealed a peak in enzymatic activity occurring 60 minutes following ACB. The highest CK-MB was significantly (P less than 0.01) lower in group II (25 +/- 8 IU/liter) than group I (50 +/- 8 IU/liter), or group III (68 +/- 14 IU/liter). Myocardial performance was evaluated after ACB by serially measuring left ventricular stroke work index (SW) and left atrial pressure (LAP) in response to volume loading. The rise in SW was significantly (P less than 0.01) greater in group II (3.0 +/- 0.7 gm.m/sq m/mm Hg) than in group I (1.4 +/- 0.7) or group III (1.8 +/- 0.9). The highest SW attained was higher (P less than .01) in group II (43 +/- 7 gm.m/sq m) than group I (19 +/- 6) or group III (34 +/- 8) at comparable LAP values (group I: 20 +/- 5 mm Hg; group II: 18 +/- 3; group III: 18 +/- 4). Post-operative clinical evaluation failed to differentiate among the three groups. The more sensitive indices, however, demonstrated the superiority of cold, multidose cardioplegia in providing optimal myocardial protection.

Anti-Arrhythmia Agents↗
PubMed1977

Assessment of myocardial performance and optimal volume loading during elective abdominal aortic aneurysm resection.

Myocardial depression has been suggested as a cause of declamping hypotension. To investigate and manage this problem, thermal dilution catheters were placed in 22 elderly, high-risk patients (mean age 71 years) who underwent elective abdominal aortic aneurysm resection. There were no deaths. Myocardial performance curves (MPC) were determined preoperatively, following induction of anesthesia, during aortic clamping, following declamping, and 12 to 48 hours postoperatively. The slope of this curve was taken as an index of myocardial performance. Preoperative cardiac index at a pulmonary artery wedge pressure of 10 mm Hg (CI10) decreased significantly following induction of anesthesia (P less than .002) and persisted during aortic cross-clamping. Following declamping, CI10 rose to preoperative levels. The slope of the MPC followed this same pattern. There was no significant change in blood pressure with the aorta clamped or following declamping. Myocardial performance is depressed following induction of anesthesia but declamping hypotension can be minimized or prevented by optimum volume loading as guided by Starling's myocardial performance curves.

Aged↗
PubMed1977

Myocardial depression during sepsis.

The cardiac response to volume loading was evaluated in fifty severely septic patients. After a rapid infusion of albumin or whole blood the cardiac index (CI) and left ventricular stroke work index (LVSWI) were recorded as the pulmonary arterial wedge pressure (PAWP) increased. Initial values of PAWP, CI, and LVSWI were similar in both the nineteen surviving and thirty-one nonsurviving patients. Surviving patients, however, demonstrated greater increases in CI and LVSWI as PAWP rose. Nearly half of both patient groups developed decreases in CI and LVSWI as the PAWP continued to increase. These downslopes occurred at relatively low PAWP and are taken as evidence of an abnormality of myocardial function in both survivors and nonsurvivors. The lower upslope of the performance curves in nonsurvivors indicates myocardial depression or a negative inotropic effect. Cardiac ischemia, acute respiratory failure, and high affinity red cells were found to diminish the cardiac response to volume loading, whereas hepatic and renal failure were associated with a good CI and LVSWI response.

Blood Pressure↗
PubMed1976

Cardiac output measurement by thermodilution during cardiac operations.

Measurement of cardiac output by the thermodilution (COTD) technique through a flow-advanced pulmonary artery catheter is simple, reliable, and practical at the bedside. Rapid repeat determinations are possible, facilitating dynamic description of myocardial performance through construction of ventricular function curves. Replicate determinations of cardiac output indicate that the thermodilution method is more accurate than the indocyanine green technique. Examples of the clinical application of COTD in cardiac surgical patients are provided.

Animals↗
PubMed1975

Clinical applications of thermodilution cardiac output determinations.

The pulmonary arterial catheter was shown to be safe and easily positioned in a group of 200 patients. Thermodilution cardiac output measurement was shown to be simple, rapid, and safe. The technic was as accurate as the simultaneously measured indocyanine green cardiac output, and more reproducible, particularly at high and low flows. The construction of myocardial performance curves during a fluid challenge is described. The value of these curves is guiding fluid, drug, and respirator therapy is illustrated by case presentations.

Aged↗
PubMed1975

Improved myocardial performance following high 2-3 diphosphoglycerate red cell transfusions.

Twenty-two matched coronary bypass surgery (CABS) patients were randomly divided into two groups; 11 patients in the control group received CPD-stored or fresh blood (mean age, 5.5 days) containing 70 percent of normal 2-3 diphosphoglycerate (2-3 DPG) and 11 patients received 2-3 DPG-enriched previously frozen, washed, concentrated red cells (2-3 DPG 150 percent of normal). Coming off cardiopulmonary bypass, when given a volume load, the high 2-3 DPG patients had a significant increase in cardiac index (2.95 L. per minute vs. 2.18 L. per minute, p smaller than 0.001) at similar filling pressures. At this time body oxygen consumption, in vivo P50, red cell 2-3 DPG, and arterial-venous oxygen content difference were all increased, but P minus vo2 was normal. Improved oxygen delivery occurred without decreasing mixed venous oxygen tension. The results suggest that, with volume loading, function in the heart with coronary artery disease is limited in part by available oxygen. By decreasing oxygen affinity for hemoglobin by altering red blood cells biochemically, myocardial performance can be improved safely.

Blood Transfusion↗