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Biomedical subjects

R Soufer

Publications and source records attributed to R Soufer.

46 records · Page 3Linked to original sources
PubMed1989

Differing responses in right and left ventricular filling, loading and volumes during positive end-expiratory pressure.

Using a combined hemodynamic and radionuclide technique, 20 patients with varied ventricular function were evaluated during positive end-expiratory pressure (PEEP) application. Left ventricular (LV) and right ventricular (RV) ejection fractions and cardiac output were measured, and ventricular volumes were derived. Seven patients (group 1) who had an increase in LV end-diastolic volume with PEEP and 13 patients (group 2) who had the more typical response, a decrease in LV end-diastolic volume with PEEP, were identified. Compared with group 2, group 1 patients had a higher incidence of coronary artery disease (5 of 7 vs 1 of 13, p less than 0.005) and lower cardiac output (3.9 +/- 1.6 vs 9.1 +/- 3.2 liters/min, p less than 0.005), LV ejection fraction (27 +/- 13 vs 51 +/- 21%, p less than 0.05), RV ejection fraction (15 +/- 6 vs 32 +/- 8%, p less than 0.005) and peak filling rate (1.32 +/- 0.43 vs 3.51 +/- 1.70 end-diastolic volumes/s, p less than 0.05). LV and RV volumes increased and peak filling rate decreased with PEEP in group 1, whereas in group 2 LV volume decreased and RV volume and peak filling rate remained unchanged. Using stepwise regression analysis, the change in LV volume with PEEP was related directly to baseline systemic vascular resistance and inversely to baseline blood pressure. Similarly, the change in peak filling rate with PEEP was inversely related to the change in RV end-diastolic volume. Thus, the hemodynamic response to PEEP is heterogeneous and may be related to LV ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Effect of positive end-expiratory pressure on right ventricular performance. Importance of baseline right ventricular function.

Thirty-six patients with diverse baseline right ventricular function were evaluated during incremental positive end-expiratory pressure (PEEP) application. Right heart pressures, cardiac output, right ventricular ejection fractions, and ventricular volumes were obtained at each PEEP level. Right ventricular peak systolic pressure-end-systolic volume relations were analyzed as an index of contractile function. Patients with severely depressed baseline right ventricular ejection fractions (30 percent or less) had an increase in end-diastolic (270 +/- 74 to 391 +/- 76 ml, 0 to 20 cm water (H2O) PEEP, p less than 0.05) and end-systolic volumes (210 +/- 70 to 321 +/- 70 ml, 0 to 20 cm H2O PEEP, p less than 0.05). These patients also had a decline in estimated right ventricular contractile function at 20 cm H2O PEEP as estimated by the slope of systolic pressure-volume relations (0.12 to 0.04 mm Hg/ml, 0 to 15 and 15 to 20 cm H2O PEEP, respectively, p less than 0.05). Patients with normal (40 percent or more) or moderately depressed (31 to 40 percent) baseline right ventricular ejection fractions had no change in right ventricular volumes or estimated contractile function. Therefore, the effect of PEEP on right ventricular function differs depending on the baseline right ventricular ejection fraction.

Adult↗
PubMed1988

The effect of incremental positive end-expiratory pressure on right ventricular hemodynamics and ejection fraction.

The effects of incremental positive end-expiratory pressure (PEEP) on right ventricular (RV) function were evaluated in 36 (n = 36) ventilated patients. Positive end-expiratory pressure was increased from 0 (baseline) to 20 cm H2O in 5-cm H2O increments and RV hemodynamics and thermally derived right ventricular ejection fraction (RVEF), right ventricular end-diastolic volume index (RVEDVI), and right ventricular end-systolic volume index (RVESVI) were computed. Right ventricular contractility was determined from the analysis of RV systolic pressure-volume relations. Right ventricular ejection fraction declined from 42 +/- 8% at baseline to 30 +/- 9% at 20 cm H2O PEEP. Right ventricular end-diastolic volume index declined between 0 and 5 cm H2O PEEP (103 +/- 42 to 92 +/- 34 ml.m-2) and then increased to 113 +/- 40 at 20 cm H2O PEEP. Right ventricular end-systolic volume index increased from 60 +/- 31 ml.m-2 at baseline to 79 +/- 34 ml.m-2 at 20 cm H2O PEEP. The slope (E) of the relation of RV peak systolic pressure to RV end-systolic volume index decreased from 0.26 mm Hg.m2.ml-1 between PEEP of 0-15 cm H2O to 0.05 mm Hg.m2.m-1 at PEEP greater than 15 cm H2O. It is concluded that low levels of PEEP have a predominant preload reducing effect on the RV. Above 15 cm H2O PEEP, RV volumes increase and E decreases, consistent with increased RV afterload and a decline in RV contractility.

Adult↗
PubMed1985

Intact systolic left ventricular function in clinical congestive heart failure.

Clinical congestive heart failure (CHF) is traditionally associated wtih significant left ventricular (LV) systolic dysfunction. Over a 1-year period, 58 patients with CHF and intact systolic function (LV ejection fraction [EF] 62 +/- 11%) were identified. An objective clinical-radiographic CHF score was used to document the clinical impression. Based on radionuclide evaluation of peak filling rate, 38% of these patients were found to have a significant abnormality in diastolic function as measured by peak filling rate (less than 2.50 end-diastolic volume/s). An additional 24% of the patients had probable diastolic dysfunction with borderline abnormal peak filling rate measurements (2.5 to 3.0 end-diastolic volume/s). The disease states most frequently associated with CHF and intact systolic function were coronary artery disease and systemic hypertension. During a 3-month sampling period 42% of patients with clinical diagnosis of CHF referred to the nuclear cardiology laboratory were found to have intact systolic function; thus, intact systolic function is not uncommon in patients with clinical CHF. Abnormal diastolic function is the most frequently encountered mechanism for the occurrence of CHF. Definition of systolic and diastolic function appears relevant for development of optimal therapeutic strategies for the treatment of patients with CHF.

Adult↗
PubMedDate not supplied

Diagnosis of pedal osteomyelitis with Tc-99m HMPAO labeled leukocytes.

The diagnosis of pedal osteomyelitis is often complicated by the presence of pre-existing bony abnormalities. In this study, the utility of radiolabeled white blood cell imaging for the detection of complicated pedal osteomyelitis was evaluated. Twenty-seven men and women were prospectively enrolled and underwent plain film radiography, three-phase bone scan, and Tc-99m hexamethylpropylamine oxine white blood cell scintigraphy of their feet. The presence or absence of osteomyelitis was confirmed in all subjects by microbiologic and histopatholigic analysis of resected bone tissue. The results indicated that white blood cell imaging was more sensitive (90%) and specific (86%) for infection than either bone scan (75% sensitive, 29% specific) or plain film radiography (55% sensitive, 57% specific). This preliminary study suggests that Tc-99m hexamethylpropylamine oxine-labeled white blood cell scintigraphy is a simple, accurate test for the detection of pedal osteomyelitis.

Aged↗
PubMedDate not supplied

Left ventricular diastolic function: physiology, methods of assessment, and clinical significance.

Diastole, that portion of the cardiac cycle that begins with isovolumic relaxation and ends with mitral valve closure, results in ventricular filling and involves both active (energy-dependent) and passive processes. The interactions between active processes (myocardial relaxation) that primarily influence early ventricular filling and passive processes, such as loading conditions, myocardial compliance, and valvular disease, are complex. Clinical methods to assess ventricular filling include cardiac catheterization, radionuclide angiography, and echocardiography. Any measurements of diastolic function must be made with an understanding of the determinants of ventricular filling and the limitations of the diagnostic test. Many cardiac disorders are characterized by elevated pulmonary venous pressures in the face of normal systolic ventricular function, which suggests a primary abnormality of diastolic function. Abnormalities in diastolic function have been observed in coronary artery disease, congestive heart failure (with and without systolic dysfunction), hypertrophic cardiomyopathy, hypertension, and in healthy elderly subjects. Identification of these abnormalities may be useful clinically, particularly in patients with symptoms of heart failure and normal systolic function. Data are not available to determine the optimal therapy for such patients, although evidence suggests that calcium channel blockers, beta blockers, and agents that reverse myocardial hypertrophy may be useful. This review briefly summarizes the physiology of diastole, the methods of clinical assessment of diastolic function, and the role of diastolic function in cardiovascular disease.

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