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M D Abel

Publications and source records attributed to M D Abel.

33 records · Page 2Linked to original sources
PubMed1992

Cemented versus noncemented total hip arthroplasty--embolism, hemodynamics, and intrapulmonary shunting.

Bone cement implantation syndrome is characterized by hypotension, hypoxemia, cardiac arrhythmias, cardiac arrest, or any combination of these complications. It may result from venous embolization that occurs in conjunction with intramedullary hypertension in the femur during insertion of the prosthesis in patients undergoing cemented total hip arthroplasty (THA). Intramedullary hypertension does not occur in patients undergoing noncemented THA. In this study, we sought to compare embolization between patients undergoing cemented and noncemented THA and to determine whether this state resulted in cardiorespiratory deterioration. In this prospective investigation of 35 patients undergoing elective THA, we used transesophageal echocardiography and invasive hemodynamic monitoring, and in 12 of them, we monitored distribution of pulmonary ventilation and perfusion intraoperatively. Embolization was significantly greater after insertion of the prosthesis in patients undergoing cemented than in those undergoing noncemented THA. Cemented THA was also associated with decreased cardiac output and increased pulmonary artery pressure and pulmonary vascular resistance. Increases in ventilation-perfusion mismatching, however, could not be demonstrated 30 minutes after insertion of the femoral prosthesis. Intraoperative monitoring for embolism may help physicians assess patients in whom cardiorespiratory function deteriorates during THA.

Aged↗
PubMed1991

An evaluation of an automated anesthesia record keeping system.

Mayo Clinic makes use of an automated anesthesia record keeping system in its cardiovascular operating rooms. Over 20,000 anesthesia records have been recorded with this system since its installation in 1983. How successful is this system? Does it meet the needs of the anesthesiologist? What are their attitudes towards the computer? A questionnaire survey was conducted to solicit the experiences, opinions, and recommendations of the users of this system. The results are described in this paper. The feedback will be used to determine the tasks and their priority for improving the current system, and to define the requirements for future computerization to meet the needs of the anesthesiologist in the operating room.

Anesthesiology↗
PubMed1990

Physiologic approach to mechanical ventilation.

An understanding of ventilator management must be predicated on physiologic principles. There is a considerable array of equipment, permitting an almost limitless number of permutations in ventilator therapy, to support patients with respiratory failure. The physician who understands patient-ventilator interactions and their effects on cardiopulmonary function will be best equipped to individualize therapy. We believe that further refinements in supportive equipment probably will not improve outcome significantly. Thus, more emphasis should be placed on elucidating the underlying disease process and its effects on respiratory structure and function.

Airway Obstruction↗
PubMed1990

Relation of pulmonary vein to mitral flow velocities by transesophageal Doppler echocardiography. Effect of different loading conditions.

It has previously been demonstrated that predictable changes occur in mitral flow velocities under different loading conditions. The purpose of this study was to relate changes in pulmonary venous and mitral flow velocities during different loading conditions as assessed by transesophageal echocardiography in the operating room. Nineteen patients had measurements of hemodynamics, that is, mitral and pulmonary vein flow velocities during the control situation, a decrease in preload by administration of nitroglycerin, an increase in preload by administration of fluids, and an increase in afterload by infusion of phenylephrine. There was a direct correlation between the changes in the mitral E velocity and the early peak diastolic velocity in the pulmonary vein curves (r = 0.61) as well as a direct correlation between the deceleration time of the mitral and pulmonary venous flow velocities in early diastole (r = 0.84). This indicates that diastolic flow velocity in the pulmonary vein is determined by the same factors that influence the mitral flow velocity curves. A decrease in preload caused a significant reduction in the initial E velocity and prolongation of deceleration time, and an increase in preload caused an increase in E velocity and shortening of deceleration time. An increase in afterload produced a variable effect on the initial E velocity and deceleration time and was dependent on the left ventricular filling pressure. The change in systolic forward flow velocity in the pulmonary vein was directly proportional to the change in cardiac output (r = 0.60). The pulmonary capillary wedge pressure correlated best with the flow velocity reversal in the pulmonary vein at atrial contraction (r = 0.81). Use of pulmonary vein velocities in conjunction with mitral flow velocities can help in understanding left ventricular filling.

Aged↗
PubMed1989

Significance of Doppler indices of diastolic filling of the left ventricle: comparison with invasive hemodynamics in a canine model.

Doppler measurements of mitral flow velocity curves have been proposed as a method for characterizing diastolic filling of the left ventricle. Different velocity curves have been empirically described in different disease states and under differing loading conditions in humans, but relating these various Doppler parameters to hemodynamic measurements of ventricular diastolic properties has not been fully elucidated. The effect of differing loading conditions (preload reduction, preload increase, afterload increase) on the Doppler mitral flow velocity and high-fidelity left atrial-left ventricular pressures was examined in seven closed-chest, anesthetized dogs. Preload reduction by balloon inflation in the inferior vena cava resulted in significant decreases in E velocity (early diastolic velocity) from 0.39 +/- 0.09 m/sec to 0.29 +/- 0.10 m/sec (p less than 0.01) and prolongation of deceleration time from 131 +/- 18 msec to 165 +/- 60 msec (p less than 0.05). Preload increase by infusion of fluids resulted in a significant increase in E velocity from 0.39 +/- 0.09 m/sec to 0.49 +/- 0.10 m/sec (p less than 0.001) and shortening of the deceleration time from 131 +/- 18 msec to 95 +/- 15 msec (p less than 0.001). The effect of afterload increase was variable and was dependent upon the left atrial pressure. Significant but weak positive correlations were noted between E velocity and maximal left atrial-left ventricular pressure gradient (r = 0.47, p less than 0.001) and total change in left ventricular pressure (r = 0.68, p less than 0.001), with inverse relationships between the deceleration time and these parameters. There was no overall relationship between the time constant tau and the E velocity, but an inverse relationship emerged when the data were examined according to different filling pressures. These results indicate that none of the mitral velocity measurements should be directly equated with other measurements of diastolic function. However, distinct velocity curves emerged under differing loading conditions that help in interpreting the meaning of these curves.

Animals↗
PubMed1989

Assessment of diastolic function of the heart: background and current applications of Doppler echocardiography. Part II. Clinical studies.

Evaluation of diastolic filling of the heart has been difficult because of its complexity and the numerous interrelated contributing factors. Previous determinations have depended on high-fidelity, invasive measurements of instantaneous pressure, volume, mass, and wall stress, which could not be done on a routine clinical basis. With the advent of Doppler echocardiography, intracardiac blood flow velocities can now be noninvasively assessed. For application of this technique to evaluation of diastolic function in patients with heart disease, it is necessary to understand what the Doppler-derived variables represent. It is also necessary to know how they are affected by changes in loading conditions and changes in myocardial relaxation. In this review, we provide an interpretation of the mitral valve, tricuspid valve, and systemic and pulmonary venous inflow velocities in the normal patient and in various disease states.

Blood Flow Velocity↗
PubMed1988

Mediastinal mass and tracheal obstruction during general anesthesia.

A 24-year-old man had a large anterior mediastinal mass and a nonproductive cough of 6 weeks' duration. With the patient under general anesthesia, a diagnostic mediastinoscopy was performed with endotracheal intubation. During the procedure, acute respiratory failure developed as a result of tracheal obstruction. Fiberoptic bronchoscopic examination of the patient in the supine position revealed almost total extrinsic compression of the trachea and no evidence of intraluminal disease. Reexamination of the trachea with the patient in sitting and semiprone positions showed resolution of the extrinsic compression and respiratory distress. Flow-volume curves obtained before treatment of the mediastinal mass (histologically diagnosed as Hodgkin's lymphoma) disclosed major airway compression with the patient in the supine position; the abnormality disappeared after chemotherapy. The mechanisms responsible for tracheal compression by mediastinal masses during general anesthesia may include the following: (1) the effect of anesthesia on pulmonary mechanics, (2) the supine body position, (3) the elimination of glottic regulation of airflow by endotracheal intubation, (4) changes related to the surgical manipulation of the tumor itself, (5) the size and location of the mediastinal mass, (6) the young age of the patient, and (7) preexisting airways disease. Anticipation and prevention of potential respiratory complications and preparedness to treat them appropriately are important aspects of the management of these patients.

Adult↗
PubMed1988

Transesophageal echocardiography: technique, anatomic correlations, implementation, and clinical applications.

The introduction of transesophageal echocardiography has provided a new acoustic window to the heart and mediastinum. High-quality images of certain cardiovascular structures [left atrial appendage, thoracic aorta, mitral valvular apparatus, and atrial septum] can be obtained readily (average examination, 15 to 20 minutes). In this article, we discuss the technique of image acquisition, image orientation, and anatomic validation. In addition, we describe our experience with the first 100 awake patients who underwent transesophageal echocardiography at our institution. The procedure was well accepted by the patients and associated with no major complications. The clinical indications for this procedure have included thoracic aortic dissection, prosthetic cardiac valve dysfunction, detection of an intracardiac source of embolism, endocarditis, cardiac and paracardiac masses, and mitral regurgitation. Transesophageal echocardiography also proved to be useful in assessment of critically ill patients in whom standard transthoracic echocardiographic images did not provide complete assessment. In these patients (who had extensive chest trauma, had undergone an operation, or were in an intensive-care unit), rapid assessment of the cardiovascular status at the bedside was possible with transesophageal echocardiography. On the basis of our initial experience, we conclude that transesophageal echocardiography complements standard two-dimensional Doppler and color flow examinations and will considerably improve the care of patients with cardiovascular disorders by providing high-quality unique images.

Aorta, Thoracic↗
PubMed1987

Evaluation of intraoperative transesophageal two-dimensional echocardiography.

Transesophageal two-dimensional echocardiography (TEE) was evaluated in 11 patients who underwent myocardial revascularization. The TEE transducer was positioned to view the left ventricular (LV) short-axis at the level of the papillary muscles (midcavity). Good quality echocardiographic images were obtainable in ten of 11 patients. Global LV function was assessed by measuring LV end-diastolic and end-systolic area and computing the fractional area change (FAC). Measurements of LV areas and FAC had excellent intraobserver reproducibility. Regional LV function was analyzed in two ways after dividing the short-axis view of the LV into four or five anatomic segments. Systolic wall thickening (SWT) of the myocardium was measured in each of four segments by digitization of the endocardial and epicardial borders of the LV and determining the fractional wall thickening. Measurements of SWT were not reproducible, primarily because of a difficulty in delineating the epicardial border of the LV accurately. In the second method, regional wall motion (RWM) in each of five segments was graded according to a previously developed scoring system. RWM analysis proved to be a measurement with excellent interobserver and intraobserver reproducibility. TEE was performed without complication and found to be a reproducible method for assessing global and regional LV function. Quantitative analysis is tedious and, therefore, currently not available on-line in the operating room.

Echocardiography↗
PubMed1985

Influence of the heart on the vertical gradient of transpulmonary pressure in dogs.

Estimations were made of the vertical gradient of transpulmonary pressure (VGTP) from measurements of esophageal pressure in nine head-up dogs at functional residual capacity (FRC) when alive, when dead, and after total bilateral pneumothorax. The VGTP of 0.4 cmH2O/cm height in the alive state was abolished by pneumothorax, and roentgenograms showed that the heart moved in a caudal-dorsal direction. There was a small but significant increase in the VGTP on going from FRC to near total lung capacity (TLC) in alive head-up dogs. In eight dead head-up dogs heart weight was increased by replacing various amounts of heart blood with Hg. The VGTP was significantly increased from 0.28 to 0.51 cmH2O/cm height. The fractional increase in the VGTP was similar to the fractional increase in heart weight. In five dogs extrapolation to zero heart weight gave an average VGTP of 0.14 cmH2O/cm height. We conclude that the lungs help support the heart in the head-up dog and that the VGTP is in part determined by the pressure distribution required for this support.

Animals↗
PubMed1983

Transfusion-related acute lung injury associated with passive transfer of antileukocyte antibodies.

Acute lung injury (ALI) is an infrequently recognized complication of transfusion therapy. Although the role of passive transfer of leukoagglutinating antibodies has been acknowledged, there is little documentation of the relationship of these antibodies in transfused blood to the human leukocyte antigen (HLA) phenotype of the recipient. Recently, we observed 5 cases of transfusion-related ALI, and in all cases leukoagglutinating and lymphocytotoxic antibodies were found in serums of the transfused blood products. In 3 cases, the antibodies corresponded to the HLA antigens of the recipient. Multiparous blood donors whose plasma contains these antibodies represent a potential transfusion hazard. It is recommended that blood component usage from donors implicated in these reactions be restricted to frozen or washed red blood cells. The incidence of leukoagglutinin-associated ALI may be more frequent than previously appreciated. Current concepts of the mechanism of microvascular pulmonary injury are discussed in relation to these cases.

Acute Disease↗
PubMedDate not supplied

Mitral flow velocity curves as a function of different loading conditions: evaluation by intraoperative transesophageal Doppler echocardiography.

Transesophageal pulsed wave Doppler echocardiography was performed intraoperatively on 10 patients undergoing coronary artery bypass operation. Mitral flow velocity curves and hemodynamic values were recorded during control conditions and intravenous infusion of (1) nitroglycerin, (2) phenylephrine, and (3) fluids. During nitroglycerin infusion blood pressure and wedge pressure decreased, peak filling velocity decreased, and deceleration time increased compared with control values. During infusion of phenylephrine blood pressure increased, there was a trend toward a decrease in peak filling velocity, and deceleration time increased. During infusion of fluids wedge pressure increased, deceleration time decreased, and peak filling velocity increased. Mitral flow velocity curves are therefore altered by changes in hemodynamic loading conditions.

Adult↗