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Biomedical subjects

R A Slutsky

Publications and source records attributed to R A Slutsky.

At least 73 records · Page 4Linked to original sources
PubMed1983

Analysis of ventricular emptying and filling indexes during acute increases in arterial pressure.

Using equilibrium radionuclide angiography, an evaluation was made of the response of left ventricular ejection and filling rates at rest and during acute increases in afterload in 8 normal volunteer subjects and 10 patients with previous transmural myocardial infarctions. Using the postatropine point for comparison, normal patients increased ejection time and decreased peak ejection rate (-3.90 +/- 0.49 vol/s to -3.41 +/- 0.95 vol/s) and peak filling rate (3.94 +/- 0.88 vol/s to 3.51 +/- 0.38 vol/s). Infarct patients had similar responses, although all indexes were lower than the corresponding values in the normal subjects. At rest, the ratio of peak filling to emptying rate was similar in the normal subjects and the infarct patients (1.01 +/- 0.24 versus 0.99 +/- 0.25, respectively) and maintained that relationship after atropine (0.91 +/- 0.11 versus 0.81 +/- 0.21) and at the peak increase in arterial pressure (1.07 +/- 0.21 versus 1.02 +/- 0.32). The ratio of time to peak filling/time to peak emptying behaved in similar fashion regardless of the differences in the absolute values. In this study, left ventricular filling and emptying behaved in a similar fashion in response to the alteration in arterial pressure in normal subjects and in patients with previous myocardial infarctions.

Adult↗
PubMed1983

Reduction in pulmonary blood volume during positive end-expiratory pressure.

The response of intravascular (PBV) and extravascular (EVLW) pulmonary fluid volumes to varying degrees of positive end-expiratory pressure (PEEP) was examined using double indicator techniques (thermal green dye) in six open-chest anesthetized dogs during the production of oleic acid (0.15 cc/kg)-induced pulmonary injury. Data were obtained at a control state, then 1.5 hr after the oleic acid was injected. Positive-end expiratory pressure (5, 10, 15, and 20 cm H2O) consistently reduced cardiac output prior to and after oleic acid edema was created, with greater reductions occurring with higher levels of PEEP. Increasing amounts of PEEP consistently produced greater reductions in PBV (with and without pulmonary edema), though without significant effect on EVLW. PBV declined from 6.0 +/- 2.4 to 4.0 +/- 1.0 ml/kg with 20 cm H2O of PEEP (P less than .01) in the control state and 4.4 +/- 2.1 to 2.9 +/0 0.9 ml/kg (P less than .01) after oleic acid administration. It is concluded that PEEP significantly reduced intravascular pulmonary fluid volumes along with cardiac output, without changing EVLW. While the effects of altered left ventricular geometry were not examined, the displacement of blood from the central to the peripheral circulation during PEEP must substantially contribute to reductions in systemic flow.

Animals↗
PubMed1983

Regional blood volume changes during acute pericardial tamponade.

Using radionuclide blood pool imaging, we evaluated sequential changes in heart, lung, liver, and spleen intravascular volumes were evaluated before and during acute pericardial tamponade in 9 anesthetized dogs. Tamponade resulted in an abrupt (less than 1 min) decline in mean right heart (-30 +/- 5%, p less than 0.001 vs control) and left heart volumes (-27 +/- 4%, p less than 0.001 vs control), with a concomitant reduction in pulmonary volume (-17 +/- 3%, p less than 0.01 vs control). Within this short time frame, both hepatic (+19 +/- 3%) and splenic (+16 +/- 4%, both p less than 0.01 vs control) volumes rose. Five min after the production of tamponade, right and left heart volumes were still significantly reduced (-28 +/- 4, p less than 0.005 vs control and -23 +/- 2%, p less than 0.005 vs control), though pulmonary (+2 +/- 5%, p = NS vs control), hepatic (+7 +/- 3%, p less than 0.05 vs control) and splenic (+9 +/- 3%, p less than 0.05 vs control) volumes had returned toward baseline values. These volume changes were similar at 20 min after tamponade. Thus, tamponade resulted in a sudden shunting of blood from the central to the peripheral circulation, initially from both the lungs and heart. After 5 min pulmonary volumes returned to baseline values, while splenic and hepatic volumes remained slightly, though significantly elevated.

Acute Disease↗
PubMed1983

Radionuclide analysis of sequential changes in central circulatory volumes: inspiration, expiration, and the Valsalva maneuver.

We evaluated the effects of deep inspiration, expiration, and the Valsalva maneuver on composite cardiac (left and right ventricular) and pulmonary volumes using equilibrium radionuclide angiography in 15 adult males without left or right ventricular dysfunction. The additional effects of nitroglycerin during these maneuvers were also examined. Midexpiration was used as the control point and data analyzed as a ratio (e.g., inspiration counts divided by midexpiration counts). Left ventricular volume (LVV) declined with inspiration (0.90 +/- 0.08 inspiratory/midexpiration) and with the Valsalva maneuver (0.89 +/- 0.08 Valsalva/midexpiration). Similar changes occurred after nitroglycerin, although the effects of the Valsalva maneuver on LVV were exaggerated when compared to the initial control intervention (0.79 +/- 0.09, vs 0.88 +/- 0.07, p less than .05). Right ventricular volume (RVV) increased with inspiration and decreased with the Valsalva maneuver; these changes were similar after nitroglycerin. Pulmonary blood volume (PBV) was greater with inspiration than expiration (1.02 +/- 0.10 vs 0.95 +/- 0.05, p less than .05), and was reduced with the Valsalva maneuver. Nitroglycerin reduced significantly all volumes and the reduction was similar for each compartment when respiratory interventions were compared. We conclude that blood pool imaging can be used to characterize abrupt fluxes in central circulatory volumes. Blood pool imaging of the heart and lungs should be considered a technique for monitoring the distribution of blood volume during acute pharmacologic and physiologic alterations.

Adult↗
PubMed1983

Analysis of the pulmonary circulation using digital intravenous angiography.

We evaluated pulmonary transit time in dogs and humans using digital intravenous angiography. Digital data were acquired in both the control state and after isoproterenol was administered to alter the inotropic state. When compared with the control value, transit time was shortened with isoproterenol in both dogs and humans. The inter- and intraobserver variabilities were small (less than 4%), as were the variabilities in data obtained from two sequential injections (less than 5%). Digital analysis of the pulmonary circulation time is a simple technique that requires little image manipulation. This information may be obtained during standard digital cardiac studies, and it can assist in the analysis of cardiopulmonary dynamics.

Angiography↗
PubMed1983

Extravascular lung water in patients with congestive heart failure. Difference between patients with acute and chronic myocardial disease.

Extravascular lung water was assessed using a double-indicator dilution technique (thermal-green dye) in 15 men who had radiographic and clinical evidence of cardiogenic interstitial and alveolar pulmonary edema. Eight patients had suffered an acute myocardial infarction and seven had a history of chronic congestive cardiomyopathy and worsening of previous clinical signs and symptoms. At the same level of pulmonary capillary wedge pressure and similar arterial oxygen tensions extravascular lung water was significantly greater in the group with chronic congestive cardiomyopathy (p less than .05). The two groups did not differ with respect to systemic arterial pressure, resistance, or cardiac index.

Acute Disease↗
PubMed1983

Effects of contrast media on pulmonary hemodynamics: comparison of ionic and non-ionic agents.

Hemodynamic effects of pulmonary arterial injections of ionic (sodium methylglucamine diatrizoate) and non-ionic contrast media (iohexol) were compared in 9 anesthetized dogs which were maintained with an open thorax in a resting control state. Both were found to increase pulmonary arterial pressure and cardiac output. In addition, both resulted in decreased systemic vascular resistance, though the effect was significantly less with the non-ionic agent. Aortic pressure did not change with the non-ionic agent but fell drastically with the ionic agent. Contrary to prevailing beliefs, the predominant response of the pulmonary circulation to contrast media was a fall rather than a rise in pulmonary vascular resistance.

Animals↗
PubMed1983

Extravascular lung water: effects of ionic and nonionic contrast media.

The effects of right atrial injections of Renografin 76 (meglumine diatrizoate), hypertonic (5%) sodium chloride, and iohexol, a new nonionic contrast medium, on sequential measures of left atrial pressure and extravascular lung water in anesthetized dogs were studied. Renografin 76 caused significant transient elevations of extravascular lung water; control levels were reestablished at 15-20 minutes after injection. These changes occurred in the absence of significant changes in left atrial pressure. Iohexol reduced extravascular lung water slightly while hypertonic saline transiently increased it. The increased extravascular lung water after right atrial injections of ionic contrast medium can only partially be explained by the tonicity of the medium. This increase was not observed with nonionic medium, suggesting that nonionic media may be preferable imaging agents in patients with underlying lung or heart disease, and may be more suitable for digital intravenous examinations.

Animals↗
PubMed1983

In vivo assessment of left ventricular wall and chamber dynamics during transient myocardial ischemia using prospectively ECG-gated computerized transmission tomography.

Seven dogs were evaluated with prospective ECG-gated computerized transmission tomography (CTT) to analyze left ventricular (LV) wall thickness and cross-sectional chamber area after acute occlusion of the left anterior descending coronary artery (LAD). ECG-gated CTT scanning during i.v. administration of contrast material was performed over the mid-left ventricle at rest, after acute occlusion of the LAD and 30 minutes after release. The extent of systolic wall thickening (EWTh) of the anterior (potentially ischemic) segment was 39.8 +/- 8.8% (SEM) in the control state and -26.0 +/- 4.7% during LAD occlusion (p less than 0.01). The nonischemic septum demonstrated a compensatory increase in EWTh, from 28.6 +/- 3.5% to 46.4 +/- 6.1% during LAD occlusion (p less than 0.05). The end-diastolic LV luminal area (LVA) increased from 17.4 +/- 0.8 cm2 in the control state to 21.0 +/- 1.1 cm2 during LAD occlusion (p less than 0.01). End-systolic LVA also increased, from 11.0 +/- 0.9 to 15.2 +/- 1.1 cm2 (p less than 0.01). In addition, the percent change in LVA from end-diastole to end-systole declined from 37.4 +/- 3.8% during control to 28.0 +/- 2.6% during LAD occlusion (p less than 0.02). In conclusion, gated CTT demonstrates that the alterations in acute ischemia are characterized by changes in regional wall thickening dynamics, consisting of wall thinning during systole in the jeopardized segment and compensatory increase in the extent of systolic thickening in the normal segment, and changes in global LV function, consisting of an increase in the LVA and a decrease in the percent change of LVA during systole. Gated CTT may be useful for monitoring regional and global effects of ischemia when subjects can be studied in the supine position and with respiration suspended for 45 seconds.

Animals↗
PubMed1983

Pulmonary edema formation with myocardial infarction and left atrial hypertension: intravascular and extravascular pulmonary fluid volumes.

The response of pulmonary blood volume (PBV) and extravascular lung water (EVLW) was examined by indicator-dilution techniques in 14 "open chest" dogs, seven that underwent coronary occlusion (group 2) and seven that served as controls (group 1). Data were obtained in a control stage (control stage 1) 45 min after coronary ligation (control stage 2), and 90 min after the left atrial pressure had been increased to approximately 35 mm Hg with a left atrial balloon. In group 2 animals, EVLW increased after coronary ligation without a marked change in left atrial pressure (6.9 +/- 0.4 to 8.2 +/- 0.5 ml/kg mean +/- SD; p less than .05) and increased to 20.1 +/- 1.4 ml/kg after the production of left atrial hypertension (p less than .005 vs control and vs coronary ligation). In the control dogs, EVLW was unchanged 45 min after the initial data had been collected (7.1 +/- 0.7 to 7.0 +/- 0.8 ml/kg). After the production of left atrial hypertension in these dogs, EVLW rose (14.8 +/- 1.2 ml/kg; p less than .005 vs control stage 1 and control stage 2, p less than .01 vs group 2 dogs). PBV did not change significantly with ligation and increased similarly in both groups during left atrial hypertension. We conclude that coronary ligation can increase EVLW, independent of microvascular hydrostatic pressure. During the production of left atrial hypertension there was greater transcapillary fluid flux in group 2 dogs at matched levels of left atrial pressure elevation. This may be due to an alteration in the permeability of the pulmonary capillary membrane during myocardial infarction and provides a partial explanation for the occasional disparity between left heart dynamics and the chest radiograph in acute myocardial infarction.

Animals↗
PubMed1983

Intravenous vs. left ventricular injection of ionic contrast material: hemodynamic implications for digital subtraction angiography.

Because of the increased use of intravenous injection of contrast material for the evaluation of cardiac structure and function by digital subtraction techniques, a study was done to assess the hemodynamic effects of contrast material when used in this fashion in man. In 10 patients, with each serving as his own control, the effects of intravenous and intraventricular injections of sodium meglumine diatrizoate (Renografin 76) in the same dose were compared. There was no difference between these two methods with respect to changes in pulmonary wedge pressures, systemic pressures, and pulmonary vascular resistance. The elevation of mean pulmonary artery and right atrial pressure was greater after the intraventricular injection (p less than 0.05). The elevated cardiac output and systemic vascular resistance returned to control values somewhat more quickly after the intravenous injection (p less than 0.001 and p less than 0.05, respectively); and the increase in cardiac output was greater after the intravenous injection at 1 min (p less than 0.05), but less than after the intraventricular injection at 2 min (p less than 0.05). Despite the detection of these statistically significant differences, the magnitude and timing of these differences are too small to justify the notion that imaging by intravenous injections of standard ionic contrast media provides any substantial hemodynamic benefits or decreased risk to the patient.

Aged↗
PubMed1983

Radionuclide evaluation of cardiocirculatory performance at rest and with exercise.

The author discusses the types of radionuclide studies performed, analyzes the methods of evaluating left and right ventricular ejection fraction and volumes, reviews methods for calculating regurgitant valvular lesions, examines the effects of exercise and diseases on cardiac dynamics, and relates cardiac and pulmonary dynamics during disease conditions and forms of stress.

Cardiac Output↗
PubMed1982

Effects of acute incremental volume overload on cardiac chamber size, function, and the pulmonary circulation: analysis by digital intravenous angiography.

To assess the effects of acute incremental volume overload on cardiac size, function, and the pulmonary circulation, we studied six anesthetized dogs using intravenous digital angiography. Aortocaval (AC) fistulas were placed in four dogs, and fistulas in both a carotid and iliac artery were placed in two dogs. Data were obtained at four points: (1) control stage; (2) partial shunt (PS, where either AC partially open or iliac fistula was open and carotid fistula was closed); (3) full shunt (FS, AC shunt open or both iliac and carotid shunts open); and (4) control stage 2. Little change in heart rate (HR) or arterial pressure occurred. With FS, both mean pulmonary artery and wedge pressures increased (p less than 0.05); however, systemic and pulmonary vascular resistances declined. Cardiac output rose (1.54 +/- 0.42 L/min at control) to 2.44 +/- 0.84 L/min at PC (P less than 0.05 vs control) and to 3.13 +/- 0.89 L/min at full shunt (p less than 0.01 vs control). Both left (0.40 +/- 0.09 to 0.55 +/- 0.10 to 0.66 +/- 0.10, p less than 0.05 and p less than 0.01 vs control, respectively) and right (0.34 +/- 0.10 to 0.40 +/- 0.10 to 0.51 +/- 0.09, the latter p less than 0.01 vs control) ventricular ejection fractions rose, as did left (30.7 +/- 13 ml to 35.1 +/- 13 ml to 37.8 +/- 13 ml, the latter p less than 0.05 vs control) and right (37.4 +/- 6.1 ml to 44.2 +/- 16.6 ml to 51.4 +/- 17 ml, the latter p less than 0.01 vs control) ventricular end-diastolic volumes. Atrial volume (determined at ventricular end-systole) also increased (9.4 +/- 3.6 ml to 11 +/- 3.5 ml to 12.9 +/- 4.3 ml, the latter p less than 0.05 vs control). These increases in cardiac function and size occurred in association with a shortening of pulmonary transit time (5.4 +/- 0.8 to 3.5 +/- 0.7 seconds to 2.9 +/- 0.5 seconds, the latter two p less than 0.05 and p less than 0.01 vs control, respectively), with no significant change in pulmonary blood volume. We conclude that acute volume overload produces cardiac chamber dilatation, along with increases in systolic function. Both pulmonary and systemic vascular resistance declined, and the transit time in the pulmonary circulation shortened. Digital intravenous ventriculography is a useful technique for the analysis of the central circulation during acute hemodynamic manipulations.

Angiography↗
PubMed1982

Right and left ventricular response to subcutaneous terbutaline in patients with chronic obstructive pulmonary disease: radionuclide angiographic assessment of cardiac size and function.

To assess the response of the right and left ventricles to the subcutaneous administration of terbutaline sulfate, a beta-2 selective agonist, we evaluated 14 patients with chronic obstructive pulmonary disease (COPD) with equilibrium radionuclide angiography (RNA). Prior to injection, eight patients (57%) had an abnormal right ventricular ejection fraction (RVEF), four (29%) had a low left ventricular ejection fraction (LVEF), and three (21%) had low ejection fractions of both ventricles. After terbutaline injection, RVEF increased in 13 of 14 patients (93%) by 17 +/- 8% (p less than 0.001) while LVEF increased in all patients by 15 +/- 7% (p less than 0.001). Both left and right ventricular end-diastolic volumes decreased (p less than 0.01), while stroke volume was unchanged. Cardiac output rose by 0.8 +/- 1.3 L/min (p less than 0.05), primarily due to the increase in heart rate (10 bpm, p less than 0.001), since stroke volume did not significantly change. We conclude that in patients with COPD subcutaneous terbutaline has significant beta-1 cardiac effects; it increases the heart rate and decreases cardiac size.

Aged↗