Decrease In Pulmonary Blood Volume Research Articles

Effect of nitroglycerin on splanchnic and pulmonary blood volume

BackgroundSublingual nitroglycerin (SL NTG) is useful for treating acute decompensated heart failure, possibly by increasing splanchnic capacitance and reducing left ventricular (LV) preload. We evaluated a radionuclide method to study these effects, initially in subjects without heart failure. Methods and ResultsRed blood cells were labelled by an in vitro method. Abdominal and chest images were obtained at rest, showing relative regional blood volumes. The abdomen was then re-imaged during progressive escalation of intrathoracic pressure using continuous positive airway pressure to assess baseline splanchnic capacitance (pressure-volume relationship, PVR) and compliance (slope of PVR). The procedure was repeated after 0.6 mg SL NTG, followed by chest images. Relative splanchnic blood volume increased at rest after SL NTG (P < .002), signifying an increase in splanchnic capacitance. The slope of the splanchnic PVR decreased in proportion to the baseline PVR (P = .0014), signifying increased compliance. The relative pulmonary blood volume decreased in proportion to the increase in splanchnic blood volume (P = .01). ConclusionsA semi-quantitative radionuclide method demonstrated the effect of SL NTG for increasing splanchnic capacitance and compliance, with a proportional decrease in pulmonary blood volume. These data may be applied to quantitatively evaluate the importance of splanchnic vasodilation as a mechanism of LV preload reduction in the treatment of heart failure.Clinical Trials Registration: NCT02425566.

Acute Hemodynamic Effects of Brescia-Cimino Arteriovenous Fistula for Hemodialysis

In ten uremic patients, who were not yet undergoing periodic hemodialysis and in whom we were creating a 1 cm, distal, side-to-side arteriovenous fistula of Brescia-Cimino type for hemodialysis, the acute hemodynamic changes of the systemic and pulmonary circulations were studied immediately after the opening of the fistula. An increase in cardiac output (Q) was observed in one patient, the other patients showing either no change or a slight reduction. In the four patients in whom the Q decreased there was a significant reduction of total blood volume (TBV) and stroke volume (SV) and an increase in systemic vascular resistance (SVR) (p less than 0.05, p less than 0.05, p less than 0.01 respectively). At the level of pulmonary circulation, in these patients a decrease in pulmonary blood volume (PBV) (mean = 20%) and a significant increase in pulmonary vascular resistance (PVR) were also observed. In five patients who had been on chronic hemodialysis and who presented the clinical picture of cardiac failure, the acute hemodynamic changes following temporary closure of the fistula (by a sphygmomanometer) were studied: a significant decrease (p less than 0.05) in Q, TBV and SV was observed. The difference between the two values of Q (i.e. fistula open and closed) was considered to indicate the magnitude of the flow across the fistula.

Effect of prolonged recombency on pulmonary blood volume in normal humans.

We have observed a progressive decrease in pulmonary blood volume during sustained recumbency measured using two independent methods. Pulmonary capillary blood volume (Vc) was estimated by the method of Roughton and Forster (J. Appl. Physiol. 11: 290, 1957). We measured regional pulmonary blood volume (PBVR) using 99mTc-labeled erythrocytes (Gorin et al., J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 45: 225, 1978). In 21 studies in 19 normal subjects, we measured pulmonary CO diffusing capacity by the single-breath technique and calculated Vc with the subjects seated and at fixed times after lying down. After 5 min in the recumbent position, there was a mean 49% increase in Vc over the value in the seated position. With sustained recumbency Vc decreased 18.3%/h over 90 min. In 12 studies in 8 normal subjects, PBVR declined 16.7%/h with prolonged recumbency in studies lasting 60-90 min. The initial increase in Vc after subjects assumed a supine position has been well described. The subsequent fall in pulmonary blood volume to levels equal to or below that measured with the subject seated has not previously been reported.

Radiologic assessment of pulmonary arterial pressure and blood volume in chronic, diffuse, interstitial pulmonary diseases.

Chronic, diffuse, interstitial pulmonary diseases may cause an increase in mean pulmonary arterial pressure (PAP) and a decrease in pulmonary blood volume (PBV). We compared 12 cardiovascular and three parenchymal assessments on plain chest radiographs with values of PAP and PBV obtained during cardiac catheterization in 29 patients with such diseases (progressive systemic sclerosis 20, sarcoidosis six, miscellaneous three) and normal pulmonary venous pressures. PAP ranged from 10 to 40 torr (mean 19, SD +/- 7), PBV from 6.4 to 10.8% of total blood volume (mean 8.4, SD +/- 1.2). PBV was significantly related to eight radiologic variables. PAP was significantly related to the severity of parenchymal disease and size of the central pulmonary arteries, both of which were assessed radiologically. Diversion of blood flow to upper zones was significantly related to restriction of the pulmonary vascular bed, but was not necessarily a sign of increased PAP. In general, pulmonary hemodynamic abnormalities appeared proportional to the radiologic severity of parenchymal disease.

Effects of acute digitalization on the pulmonary blood volume in patients with heart disease.

Basic hemodynamic data and the pulmonary blood volume (PBV) were determined in 23 patients before and after intravenous administration of acetyl strophanthidin during right and left heart catheterization. These patients were divided into two groups depending upon whether or not digitalization produced a significant fall in left ventricular end-diastolic pressure (LV D ). Group I consisted of 11 patients who manifested a significant decrease in LV D , while in group II no change was noted after digitalization. In both groups, a significant rise in LV stroke volume, stroke work, and maximal rate of rise of LV systolic pressure (dp/dt) was recorded. In group I, a significant decrease in the pulmonary vascular distending pressure (P d ) was accompanied by a decrease in PBV. In contrast, no change in P d or PBV was noted in the patients in group II. Changes in pulmonary vascular resistance (PVR) were inconsistent. It is concluded that: (1) in patients of group I the concordant decrease in P d and PBV represented a passive effect on the pulmonary vascular bed mediated by improved LV performance and decrease in LV D ; (2) in patients of group II, despite evidence of significant positive inotropic effects on the left ventricle, the failure of LV D to fall prevented a decrease in P d and PBV; (3) no evidence of active vasomotor effects of acetyl strophanthidin in the lung could be demonstrated. Changes in PVR were capricious and not apparently useful in assessment of the presence or absence of pulmonary vasomotor effects induced by digitalis. The results of this study differ from the findings of other investigators in cardiac patients and experimental animals. Some of the differences may be attributed to different experimental methods and to species variation in vascular reactivity. Also, the findings in this report contrast with those previously reported for isoproterenol and aminophylline, agents that produce both positive inotropic effects on the heart and active vasomotion in the pulmonary circulation.

Transthoracic Impedance: V. Effects of Early and Late Clamping of the Umbilical Cord with Special Reference to the Ratio Air‐to‐Blood during Respiration

SummaryTransthoracic impedance TTI in combination with recordings of air volume change and oesophageal pressure has been used to analyze time dependent variations in the ratio airlfluid during the first day of life, as well as the dynamic interrelationship between air and fluid in the lungs during respiration.Two groups of infants, seven with early and seven with late clamping of the umbilical cord, were studied a t 2, 6, 12 and 24 hours of age. These groups are known to have a dif‐ference in total blood volume, decreasing during the time of study.Especially in late‐clamped infants charac‐teristic changes in impedance variables are noted. Basic transthoracic impedance lZo(, reflecting the static ratio air/fluid, is initially low and increases till 12 hours of age, a net result of a decrease in pulmonary blood volume, interstitial fluid and possibly some contribu‐tion from an increase in pulmonary air volume.A tendency towards a fall in IZ, I from 12 to 24 hours coincides with an enlargement of the total blood volume.Variations between early and late‐clamped infants are larger for the dynamic impedance variables than for IZoI. The ratio IZ, I/V, of impedance variation per unit air volume change during respiration is higher for late‐clamped infants during the whole study, though decreasing with time. This implies that these infants have a larger amount of fluid in the lungs as compared with early‐clamped infants, also decreasing with time. n accordance with the presented physical model for volume relations in the lungs the amount of blood that needs to be moved into the lungs with inspiration is relatively smaller when the pulmonary blood volume is higher.A looped relation between air volume change and impedance change during a breath lZdl, is most pronounced in late‐clamped infants a t the commencement of the study, significantly decreasing with time. The existence of a IZ, I means that a larger blood volume than necessary for the geometrical requirements has entered the lungs during inspiration, a volume that is allowed to leave in early expiration. The prerequisite of a high IZ, I is a large pulmonary blood volume. For infants with early clamping of the umbilical cord no significant variations are noted in the impedance variables.It is concluded that late‐clamped infants, compared to early‐clamped infants, in addition to their larger total blood volume also have larger pulmonary fluid volume, the increment, mainly consisting of blood. A correlation found between change in lung compliance and the impedance variables, especially con‐cerning the late‐clamped group, and a suggestion is made that lung compliance varies inversely with the pulmonary fluid volume.

RESPONSE OF THE PULMONARY VEIN TO RAPID BLOOD TRANSFUSION IN INTACT DOGS.

Abstract Using a modification of the transeptal technique of cardiac catheterization, pulmonary venous responses to rapid bood transfusion, were studied in 10 intact dogs. It was found that immediately following whole blood transfusion (mean 26.9 ml. per kilogram) mean left atrial pressure, pulmonary venous pressure, and pulmonary blood volume increased. However, between 3 and 18 minutes after completion of the transfusion, pulmonary venous pressure returned to control levels, whereas pulmonary blood volume remained unchanged. During this same period, left atrial pressure decreased, but it remained significantly above the control. These studies indicate that, following rapid blood transfusion, the pulmonary venous system behaved as a distensible reservoir accomodating a large volume of blood with only a transient rise in pressure. The fact that between 3 and 18 minutes after transfusion pulmonary venous pressure decreased in the absence of a decrease in pulmonary blood volume while left atrial pressure remained significantly elevated indicates that there was an active decrease in pulmonary venous tone. It is concluded that the pulmonary venous system plays an active role in the immediate hemodynamic adjustments to sudden hypervolemia.

Effects of inhalation of 100 per cent oxygen on the pulmonary blood volume in patients with organic heart disease.

The effect of breathing 100 per cent oxygen on the pulmonary blood volume, pulmonary arterial pressure, left atrial pressure, and pulmonary vascular distending pressure was studied during cardiac catheterization in eight patients with organic heart disease. In half of the patients, a significant decrease in pulmonary blood volume was observed. This decline in pulmonary blood volume in the face of a decrease or no change in the pulmonary distending pressure is interpreted as evidence for a passive mechanism of action for 100 per cent oxygen. The effects of hyperoxia are compared to those of acetylcholine, which works by actively dilating the pulmonary vascular bed.

Studies on the pulmonary diffusing capacity and the pulmonary circulation with special reference to the haemodynamic aspects of the average contact time.

1) The method of estimating the average contact time through simultaneous measurements on the red cell component of the apparent pulmonary diffusing capacity and the effective pulmonary blood flow. 2) The physiological basis of the present method was introduced. 3) The average contact time in cases of normal healthy was ranged between 0.3-0.5 sec and that in cases of any cardiopulmonary diseases had revealed various degree of restriction. 4) The average contact time has been studied in relation with any haemodynamic factors of the pulmonary circulation and some physiological significance of the average contact time was reported. 5) As for the cause of the restriction of the average contact time, the authors have pointed out the following items : such as a) increase in cardiac output, b) decrease in effective pulmonary capillary beds, c) decrease in pulmonary blood volume, etc. 6) The importance and necessity of further investigations to give any definite conclusion on the physiological mechanism to cause any restriction of the average contact time was emphasized.

Effects of serotonin on pulmonary blood volume in the dog

Changes in pulmonary blood volume produced by continuous intravenous infusion of serotonin (5-hydroxytryptamine) were measured in 16 experiments on ten dogs. Pulmonary mean transit time was measured by the dye dilution method, using consecutive injections into pulmonary artery and left atrium; pulmonary blood volume was calculated by multiplying this mean transit time by the cardiac output. Serotonin lowered pulmonary blood volume by an average of 2.9 ml/kg, or 26% of the control value ( P &lt;0.001). Pulmonary vascular resistance increased 94 ru (resistance units) kg, and systemic vascular resistance fell 294 ru kg, effects similar to those reported by other investigators. The magnitude of the decrease in pulmonary blood volume indicates that a relatively large part of the pulmonary vascular bed is constricted by serotonin, and provides an example of shifting of blood from pulmonic to systemic circuits by reciprocal changes in the distensibility of these beds.

Observations on Cardiac Output and ”Pulmonary Blood Volume” in Normal Man by External Recording of the Intracardiac Flow of 131I Labelled Albumin

Summary1. The technique for the measurement of cardiac output by external recording of the intracardiac flow of 131I labelled human serum albumin has been extended to provide a measure of the mean circulation time from right to left heart and hence a new approach to the estimation of the pulmonary blood volume.2. Values for the basal cardiac output in normal subjects and its variations with age are in good agreement with the previously published data of other workers.3. The pulmonary blood volume in normal man in the basal state was found to be 28.2 ± 0.6% of the total blood volume.4. There was no correlation between cardiac output and pulmonary blood volume in a series of normal subjects in the basal state.5. The increase in cardiac output during digestion was associated with a decrease in pulmonary blood volume equal to 6.3 ± 1.2% of the total blood volume, that is, about 280 ml.6. The increase in cardiac output during exercise was associated with a decrease in pulmonary blood volume equal to 4.5 ± 1.0% of the total blood volume, that is, about 200 ml.7. The increase in cardiac output attributed to alarm is not associated with a decrease in pulmonary blood volume, the latter may in fact be increased.8. The total blood volume is advocated as a standard of reference for studies of this type in normal subjects in preference to body weight or surface area.9. The significance of these results and the validity of the method are discussed.