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PubMed1984

Right heart function during left heart assist and the effects of volume loading in a canine preparation.

A significant fraction of patients in whom mechanical left ventricular assist devices are implanted for refractory cardiac failure after open heart surgery have had the complication of right heart failure. To evaluate the effects of left ventricular assistance and pressure unloading on right ventricular function, we performed experiments in the normal hearts of open-chest, anesthetized, large mongrel dogs. We compared right ventricular function before and after left ventricular-to-aortic bypass with a roller pump at right atrial pressure levels of 1, 3, 5, and 7 mm Hg produced by volume loading. No significant changes were found in cardiac output or stroke volume over this range of right atrial pressures when comparing that before to that during left ventricular bypass, which at a right atrial pressure of 1 mm Hg reduced peak left ventricular pressure from 96 +/- 6 to 15 +/- 9 mm Hg and at a right atrial pressure of 5 mm Hg reduced it from 113 +/- 3 to 29 +/- 12 mm Hg, while maintaining aortic pressure. There was no evidence of right ventricular failure under these conditions: (from before to during bypass) at a right atrial pressure of 1 mm Hg cardiac output was 3.4 +/- 0.4 to 3.7 +/- 0.6 liter/min and stroke volume was 28 +/- 5 to 33 +/- 6 ml; during volume loading at a right atrial pressure of 7 mm Hg cardiac output was 5.6 +/- 0.6 to 5.7 +/- 0.7 liter/min and stroke volume was 47 +/- 5 to 52 +/- 5 ml.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Ventilatory responses to exercise in adults after repair of tetralogy of Fallot.

BACKGROUND: Adult patients with total correction of tetralogy of Fallot may have poor exercise capacity associated with impaired right heart function and in particular pulmonary regurgitation. The ventilatory responses to exercise were studied in a group of such patients to assess relations between ventilation, exercise capacity, and right ventricular function. METHODS: 30 patients (7 female) (aged 27.8 (6.0) years) and 30 (7 female) controls of a similar age range were studied prospectively. All underwent exercise testing with metabolic gas exchange to determine peak oxygen consumption (peak VO2), and (as indices of the ventilatory response) the slope of the relation between both respiratory rate (RR) and ventilation (VE) against carbon dioxide production (VCO2). Patients were studied with pulsed wave Doppler echocardiography to determine pulmonary arterial systolic and diastolic flow characteristics. Patients were defined as having restrictive right ventricular function where diastolic pulmonary forward flow was seen coincident with atrial systole. RESULTS: In the group with tetralogy of Fallot mean (SD) peak VO2 was 35.3 (7.5) ml/kg/min (93.6 (15.3) % of expected for age, weight, height and sex). The RR/VCO2 slope was steeper in the Fallot group (6.8 (2.6) v 9.6 (4.7), P < 0.02). Those with restrictive right ventricles achieved a higher peak VO2 than those without (82.5 (10.1) % v 100.9 (13.8), P < 0.001). In the Fallot group alone, there was an inverse relation between ventilatory response and peak VO2 (RR/VCO2 v peak VO2; r = -0.63, P = 0.003: VE/VCO2 v peak VO2; r = -0.62, P < 0.001). CONCLUSIONS: Many of these patients with repaired tetralogy of Fallot had near normal exercise capacity, but as exercise capacity decreased, the ventilatory response to exercise increased. This was not due to alterations in pulmonary function tests or to the effects of cardiac size causing decreased lung volume. It may be that the increased ventilatory rate at a given level of carbon dioxide production acts as a respiratory pump aiding right ventricular function.

Adult↗
PubMed1996

Nitric oxide synthesis inhibition and right ventricular systolic function in swine.

OBJECTIVES: The present study was designed to evaluate the effects of the nitric oxide synthesis inhibitor NG-nitro-L-arginine methyl ester (L-NAME) on right ventricular (RV) contractility, both pulsatile and nonpulsatile contributions to afterload, and relate any changes to alterations in performance of the RV as a pump. DESIGN: Prospective drug response. SETTING: University animal laboratory. PARTICIPANTS: Swine. INTERVENTIONS: Six pigs anesthetized with thiopental and fentanyl were instrumented for measurement of RV pressure and pulmonary arterial (PA) pressure, internal diameter, and blood flow. Total RV afterload was calculated as effective PA elastance, with the steady-state component expressed as total arterial resistance, and the pulsatile component assessed by calculation of characteristic impedance and global compliance. The ratio of peak PA flow to RV end-diastolic pressure (RVEDP) was recorded as an index of RV pump function, and the peak ejection rate-of-change of RV power (dPower/dt) was calculated as an index of contractility. In each animal, measurements were obtained before (baseline) and 15 minutes after intravenous injection of 33 mg/kg of L-NAME. MEASUREMENTS AND MAIN RESULTS: Mean PA pressure increased from 14 +/- 3 mmHg at baseline to 23 +/- 6 mmHg after L-NAME, whereas cardiac output, stroke volume, and peak PA flow/RVEDP demonstrated declines and dPower/dt was unchanged. Simultaneously, effective PA elastance increased more than twofold. This increase in total RV afterload was primarily the result of a marked elevation in total arterial resistance (+156%), whereas vascular compliance was reduced by only 30% and characteristic impedance unchanged. CONCLUSIONS: These data indicate that L-NAME produces constriction of resistance vessels within the lung, leading to increased steady-state RV afterload, but had little direct effect on large pulmonary vessels and pulsatile RV load. RV pump performance declines after L-NAME, but contractility is preserved, indicating that the change in systolic performance results primarily from the increase in steady-state afterload.

Animals↗
PubMed1999

Effect of age, heart rate and tricuspid regurgitation on the Doppler echocardiographic evaluation of right ventricular diastolic function.

Pulsed-wave Doppler analysis of tricuspid inflow and hepatic venous flow allows the determination of multiple parameters of right-ventricular (RV) diastolic function. This study sought to evaluate the influence of heart rate, age and tricuspid regurgitation on Doppler parameters of RV diastolic performance. We studied 80 subjects (20 normal and 60 with RV pathology) with Doppler recordings of the tricuspid inflow and hepatic vein. All tricuspid Doppler parameters were dependent on heart rate, age or regurgitation severity as were the hepatic vein S wave, S/D ratio and systolic filling fraction. The atrial reversal velocity in the hepatic vein Doppler tracing was not affected by age, heart rate or regurgitation. In addition, the inspiratory increase in this parameter was significantly elevated in RV pathologic states. This study demonstrates that most Doppler echocardiographic parameters of RV diastolic performance are dependent on age, tricuspid regurgitation or heart rate.

Adult↗
PubMed1989

Assessment of right ventricular anatomy and function by quantitative radionuclide ventriculography.

Determination of right ventricular ejection fraction and volumes from radionuclide studies is cumbersome and is subject to considerable methodologic error. Further, assessment of regional wall motion has only infrequently been approached in a systematic way. A system of right ventricular ejection fraction and volume measurements is described that utilizes the previously validated single plane geometric method applied to first pass radionuclide angiocardiograms. Five right ventricular chords were defined and used to assess regional wall motion; normal values were obtained from 14 patients who were without demonstrable cardiac disease. Among 23 patients with anterior myocardial infarction, the right ventricular ejection fraction was within 2 SD of normal in 16; however, 3 of these patients showed regional wall motion abnormalities in the right ventricle. Of 21 patients with inferior myocardial infarction, right ventricular ejection fraction was reduced in 15; of the 6 with normal values, 3 had regional wall motion abnormalities as demonstrated by the chord shortening method. Of 21 patients with dilated cardiomyopathy, right ventricular function was abnormal in 20; the presence of a wall motion abnormality in the conus segment separated these patients from patients with right ventricular dysfunction after recent myocardial infarction. Thus: 1) right ventricular ejection fraction, volumes and wall motion can be assessed by a simple, geometric technique; 2) analysis of chord shortening by this method provides information unavailable from global ejection fraction data alone; and 3) the clinical correlates of these data will require further investigation.

Adult↗
PubMed1992

Transesophageal Echo-doppler evaluation of the hemodynamic effects of positive-pressure ventilation after coronary artery surgery.

Transesophageal echocardiography was used to extend knowledge about the impact of positive end-expiratory pressure (PEEP) during mechanical ventilation on right and left ventricular function and right ventricular impedance. At 20 cmH2O PEEP, a progressive increase of right ventricular end-diastolic area was seen (27%) that coincided with a reduction of early left ventricular filling velocity (25%) across the mitral valve, and a decrease of both pulmonary artery flow velocity (end-expiration 27% and end-inspiration 42%) and time-velocity index (end-inspiration 25%). As these changes were not accompanied by a change of the fractional area of contraction, the increase of the right ventricular diameter might be explained by right ventricular compensation due to an imbalance between augmented right ventricular impedance and reduced venous return.

Adult↗
PubMed2001

Independent and additive prognostic value of right ventricular systolic function and pulmonary artery pressure in patients with chronic heart failure.

OBJECTIVES: We sought a better understanding of the coupling between right ventricular ejection fraction (RVEF) and pulmonary artery pressure (PAP), as it might improve the accuracy of the prognostic stratification of patients with heart failure. BACKGROUND: Despite the long-standing view that systolic function of the right ventricle (RV) is almost exclusively dependent on the afterload that this cardiac chamber must confront, recent studies claim that RV function is an independent prognostic factor in patients with chronic heart failure. METHODS: Right heart catheterization was performed in 377 consecutive patients with heart failure. RESULTS: During a median follow-up period of 17 +/- 9 months, 105 patients died and 35 underwent urgent heart transplantation. Pulmonary artery pressure and thermodilution-derived RVEF were inversely related (r = 0.66, p < 0.001). However, on Cox multivariate survival analysis, no interaction between such variables was found, and both turned out to be independent prognostic predictors (p < 0.001). It was found that RVEF was preserved in some patients with pulmonary hypertension, and that the prognosis of these patients was similar to that of the patients with normal PAP. In contrast, when PAP was normal, reduced RV function did not carry an additional risk. CONCLUSIONS: These observations emphasize the necessity of combining the right heart hemodynamic variables with a functional evaluation of the RV when trying to define the individual risk of patients with heart failure.

Adult↗
PubMed1993

Determinants of the recovery of right ventricular performance following experimental chronic right coronary artery occlusion.

BACKGROUND: Patients with acute ischemic right ventricular dysfunction often develop hemodynamic compromise, yet most manifest spontaneous early clinical improvement and later recovery of global right ventricular performance. This study was designed to delineate the determinants of right ventricular performance following chronic right coronary artery occlusion. METHODS AND RESULTS: Thrombotic right coronary artery occlusion was induced in 16 closed-chest dogs. Acute occlusion depressed right ventricular free wall motion (motion score, 1.0 +/- 0.0 to 3.4 +/- 0.1*) and global performance (right ventricular fractional area change, 29.2 +/- 1.8% to 2.3 +/- 1.9%*). There was right ventricular dilatation and reversed septal curvature, with elevated and equalized diastolic filling pressures. At 5 days, despite persistent severe right ventricular free wall dysfunction (motion score, 3.4 +/- 0.1 to 2.7 +/- 0.1*), global right ventricular performance improved (fractional area change, 2.3 +/- 1.9% to 17.0 +/- 3.8%*), in part due to reduced right ventricular free wall dyskinesis associated with increased right ventricular free wall end-diastolic thickness. At 7 weeks, collateral flow had restored right ventricular free wall perfusion to baseline values. The increased right ventricular free wall thickness had resolved, right ventricular free wall motion was improved (2.7 +/- 0.1 to 1.6 +/- 0.1*), and global right ventricular performance had recovered further (17.0 +/- 3.8 to 20.9 +/- 0.9). Right ventricular dilatation was reduced, septal curvature normalized, and there was resolution of equalized filling pressures. Histopathological analysis demonstrated minimal right ventricular infarction. CONCLUSIONS: Acute right coronary artery occlusion results in right ventricular free wall dyskinesis and depressed global right ventricular performance. Global right ventricular function improves early, in part due to reduced right ventricular free wall dyskinesis associated with increased right ventricular free wall diastolic thickness. Collateral restoration of perfusion facilitates late recovery of right ventricular free wall function (*P < .05).

Animals↗
PubMed1986

Effect of beta-blockade on right ventricular performance in patients with and without right ventricular dysfunction due to coronary artery disease.

To assess the effects of beta-blockade on right ventricular performance in patients with and without right ventricular dysfunction due to coronary artery disease, we performed radionuclide ventriculography on eight patients with normal right ventricular ejection fraction (RVEF greater than or equal to 35%) and 14 patients with mild to moderate right ventricular dysfunction (RVEF less than 35%) at rest. All patients had chronic stable angina pectoris, and nine patients had prior myocardial infarction. Radionuclide ventriculography was performed on placebo and during clinical beta-blockade (heart rate, 50 to 60 beats per minute and less than or equal to 20% increase in heart rate over baseline during stage I treadmill exercise, Bruce protocol) with the oral, cardioselective beta-blocking agent, betaxolol. The resting RVEF (mean +/- 1 SD) was 33% +/- 7% on placebo and 34% +/- 7% during clinical beta-blockade. Mean exercise RVEF was 40% +/- 8% on placebo and 39% +/- 8% during clinical beta-blockade. These differences were not statistically significant. Resting left ventricular ejection fraction ranged from 22% to 60% (mean, 42% +/- 8%). On placebo, one of eight patients with a resting RVEF greater than or equal to 35% had a normal exercise RVEF response (greater than or equal to 5% increment) whereas nine of 14 patients with resting RVEF less than 35% had normal exercise response. The discordant relationship between baseline RVEF and exercise response on placebo became less marked during clinical beta-blockade. We conclude that beta-blockade does not produce significant deterioration of right ventricular systolic function or right ventricular reserve either in patients with normal or in those with mild to moderately impaired resting right ventricular systolic function.

Adrenergic beta-Antagonists↗
PubMed1992

The right ventricle in disorders causing pulmonary venous hypertension.

The right ventricle is frequently affected by pulmonary arterial hypertension of postcapillary obstructive origin. The disorders that cause states of pulmonary venous hypertension arise in the left ventricle, left atrium, or pulmonary veins. Biochemical factors, the pericardium, interventricular septum, and pulmonary arterial system combine to communicate the effects of these disorders to the right ventricle. Although not ideally suited to pressure loading, the right ventricle undergoes a series of structural and hemodynamic adaptations that allow for chronic compensation until failure supervenes, with characteristic clinical findings. Exercise may serve to magnify the abnormalities of right ventricular function. Correction of left-sided heart lesions with improvement in pulmonary venous hypertension is associated with favorable effects on the right ventricle. In states of left-sided heart failure, the level of right ventricular function may provide important prognostic information.

Heart Diseases↗
PubMed1996

Xamoterol improves right ventricular systolic and diastolic function in pulmonary heart disease.

OBJECTIVE: Abnormal right ventricular function in patients with pulmonary heart disease (PHD) may contribute to their reduced exercise capacity. We have evaluated the effect of subacute dosing with xamoterol, a beta-1 adrenoreceptor partial agonist with inotropic properties, on right ventricular function in patients with PHD. PATIENTS: Twelve patients with advanced chronic obstructive pulmonary disease and clinical evidence of PHD received xamoterol 200 mg twice daily or placebo for 7 days in a randomised double-blind crossover study. Right heart krypton-81m radionuclide ventriculography was used to derive right ventricular ejection fraction (RVEF) both at rest and during submaximal exercise, and indices of right ventricular systolic and diastolic function at rest. RESULTS: During treatment with placebo, mean RVEF was 0.53 at rest and was unchanged during exercise. After xamoterol, mean RVEF was 0.55 at rest and increased to 0.59 during exercise. Xamoterol increased right ventricular peak ejection rate from 3.04 to 3.45 EDV.s-1 and mean early diastolic filling rate from 1.00 to 1.20 EDV.s-1. CONCLUSION: Subacute treatment with xamoterol in patients with PHD improves right ventricular systolic and diastolic function at rest and results in a favourable augmentation in right ventricular function during submaximal exercise.

Aged↗
PubMed1992

Functional changes in the right and left ventricle during development of cardiac hypertrophy and after its regression.

OBJECTIVE: The aim was to determine left and right ventricular functional reserves and collagen concentration during the development of cardiac hypertrophy and after its regression. METHODS: Two experimental models of cardiac hypertrophy (chronic thyroxine or isoprenaline treatment of adult rats) were compared 24 h and five weeks after the agent was last given. Pressure changes in the left (right) ventricle before and after acute aortic (pulmonary artery) ligation were recorded in open chest anaesthetised animals. The difference in dP/dtmax after and before ligation was regarded as the functional reserve. The total collagen concentration was determined in both ventricles separately by means of hydroxyproline. RESULTS: Left and right ventricular weight increased by 20% and 30% respectively in the two models employed. In the thyroxine treated group, the functional reserve of the left ventricle rose very noticeably, whereas in the isoprenaline treated group it decreased. The right ventricular functional reserve did not differ from that in the controls in either of the two groups. The collagen concentration rose in the left ventricle in the isoprenaline group only. Five weeks after the last administration of the agent, cardiac mass and ventricular function did not differ from the control values in either of the models studied; the only exception was the incomplete regression of left ventricular hypertrophy and persistent structural and functional impairment of the left ventricle in the isoprenaline treated group. CONCLUSIONS: Our results indicate that hearts undergoing a comparable degree of experimental hypertrophy may have different functional and structural properties; significant differences were found between the right and left ventricular response. Regression of hypertrophy together with a reversal of ventricular function usually occurs unless the myocardium has received severe structural damage.

Animals↗
PubMed1995

Assessment of right ventricular diastolic function by pulsed Doppler echocardiography in chronic pulmonary disease and pulmonary thromboembolism.

We evaluated right ventricular (RV) diastolic performance in 12 healthy subjects (control), 25 patients with chronic pulmonary diseases (CPD) and 6 patients with chronic pulmonary thromboembolism (PTE). Flow velocity patterns were determined by the pulsed Doppler technique. The values determined included acceleration time (AT), deceleration time (DT), and the ratio of the atrial contraction wave (A) to the rapid filling wave (R) (A/R ratio) from flow velocity patterns in the RV inflow tract. DT was significantly prolonged in the CPD and PTE groups compared with the control group, indicating dysfunction during the early (middle) filling period. The prolongation was marked in those patients with pulmonary hypertension. The A/R ratio was significantly higher in the CPD and PTE groups than in the control group, indicating a decrease in RV compliance. The A/R ratio increased slightly with the increase in the end-diastolic volume index. These results suggested that the pressure overload plays an important role in RV diastolic dysfunction in patients with pulmonary disease, and that preload contributes to the dysfunction.

Aged↗
PubMed2005

Two simple echo-Doppler measurements can accurately identify pulmonary hypertension in the large majority of patients with chronic heart failure.

BACKGROUND: The assessment of pulmonary hypertension in patients with heart failure is of great clinical importance not only for diagnostic purposes but also for prognostication. The present study was undertaken on a consecutive basis with a group of patients with chronic heart failure. Patients were evaluated for their suitability for heart transplantation: (1) to explore the diagnostic accuracy of several echo Doppler parameters of pulmonary hemodynamics in predicting the presence of elevated pulmonary artery pressure (defined as pulmonary artery systolic pressure > or =35 mmHg and mean pulmonary artery pressure >20 mmHg); (2) to assess the diagnostic ability of the same parameters to identify patients with elevated pulmonary vascular resistance; and (3) to evaluate the influence of right ventricular function and degree of tricuspid regurgitation in modifying diagnostic accuracy. METHODS: Echo Doppler examination and right heart catheterization were performed consecutively within 24 hours in 86 patients. The optimal cut-off value for a series of echo Doppler parameters capable of identifying patients with pulmonary hypertension was obtained by dividing the entire sample into 2 groups; the optimal threshold (highest sensitivity and specificity) of the echo and Doppler parameters used to classify patients with and without pulmonary hypertension was determined in 67% of cases by means of the receiver operating characteristic (ROC) curve: this was the testing sample. The proportion of cases classified correctly according to the selected cut-off was computed. The remaining 33% of cases represented the validation sample: sensitivity, specificity and predictive values (and their 95% confidence intervals [CIs]) for identifying pulmonary hypertension were calculated from the proposed cut-offs in this second sample. Finally, the overall performance of the echo Doppler parameters was assessed over the whole sample by considering the extent of the area under the ROC curve (A-ROC) and its 95% CI, for the dichotomic measurement. RESULTS: On right heart catheterization, a pulmonary artery systolic (PAPs) pressure > or =35 mmHg plus a mean pressure (mean PAP) >20 mmHg was documented in 49 of 86 cases (57%), for whom mean values were 56 +/- 17 and 38 +/- 11 mmHg, respectively. The proportion of cases identified correctly as having pulmonary hypertension was highest for PAPs (88%) and mean PAP (85%) in addition to acceleration time of pulmonary artery systolic flow (ACT) (79%) and pulmonary artery diastolic pressure obtained utilizing the early phase of the tricuspid regurgitation spectral flow (PAPd/TR) (75%). PAPd/TR performed better in the validating sample in terms of diagnostic ability, with high sensitivity and specificity (100% and 60%) and positive and negative predictive values (PPV 80%, NPV 100%). PAPs, mean PAP, ACT and PAPd/TR confirmed their prevailing diagnostic ability (A-ROC from 0.74 to 0.86) in identifying pulmonary hypertension with fair to high feasibility (67% to 91%) and an odds ratio (OR) indicative of strong association. ACT and PAPd/TR, the 2 parameters with the highest feasibility, allowed us to identify 46 of 49 (94%) hypertensive cases. The same parameters did not perform well in identifying patients with increased vascular resistance, with A-ROC ranging from 0.55 to 0.69. Heterogeneity of effect, due to right ventricular function or tricuspid regurgitation degree, could not be demonstrated in the ability of the echo Doppler measurements to identify pulmonary hypertension. CONCLUSIONS: ACT, PAPd/TR, PAPs and mean PAP have been shown to accurately classify patients with chronic heart failure with or without pulmonary hypertension. In particular, ACT and PAPd/TR alone allowed reliable and accurate definition of pulmonary hypertension in 94% of patients, regardless of right ventricular function or degree of tricuspid regurgitation. Non-invasive pulmonary pressure assessment by the referred method might be useful in the evaluation of heart transplant candidates.

Adolescent↗
PubMed1980

Monitoring cardiac function with nuclear techniques.

Noninvasive imaging with radioactive tracers has become widely used since its introduction in the early 1970s. Improvements continue to be made in the techniques and the clinical applications. Much of the information provided by these techniques is new. The first transit studies are used mainly in the evaluation of pulmonary transit time, detection of intracardiac shunting, evaluation of right ventricular function, measurement of ejection fraction and detection of wall motion abnormalities at rest and after exercise. The gated blood pool study is found to be most useful in assessment of global left ventricular function, regional wall motion, valve regurgitation and right ventricular function. The techniques of nuclear cardiac imaging are noninvasive, simple, successfully performed in almost 100 percent of cases. They are easy to interpret, able to be quantified and able to be almost totally automated. Their use is likely to become more widespread in the future.

Coronary Disease↗
PubMed1994

The pulmonary circulation and the heart in chronic lung disease.

Most studies devoted to the investigation of pulmonary haemodynamics and right ventricular function in chronic lung diseases have concerned patients with chronic obstructive pulmonary disease (COPD). In COPD, pulmonary hypertension is closely linked to the presence of chronic alveolar hypoxia. Pulmonary hypertension is most often mild to moderate (mean pulmonary artery pressure (PAP) in the range 20-35 mmHg) but it may worsen markedly during acute exacerbations of the disease, sleep and exercise. Long-term oxygen therapy is the logical treatment for hypoxic pulmonary hypertension. In time, pulmonary hypertension leads to right ventricular enlargement, which includes right ventricular hypertrophy and dilatation. This is a beneficial adaptation, allowing the right ventricle to cope with an increased afterload and to maintain a normal cardiac output. The right ventricular function, and in particular the right ventricular contractility, are generally preserved in patients with advanced COPD. "True" right ventricular failure can be observed during acute exacerbations of the disease, when worsening of hypoxaemia induces a marked increase in afterload (PAP and pulmonary vascular resistance).

Heart Diseases↗
PubMed1999

Inhaled nitric oxide does not improve cardiac or pulmonary function in patients with an exacerbation of chronic obstructive pulmonary disease.

OBJECTIVE: To determine whether inhaled nitric oxide (NO) improves right ventricular function in mechanically ventilated patients with severe chronic obstructive pulmonary disease (COPD). DESIGN: Open, prospective, controlled trial. SETTING: General intensive care unit of a community hospital. PATIENTS: Twelve patients with acute respiratory failure caused by acute exacerbation of COPD requiring mechanical ventilation. INTERVENTIONS: Insertion of a pulmonary artery catheter modified with a rapid response thermistor and a radial arterial catheter. Nitric oxide was then administered to the patient via a T piece placed between the Y piece of the ventilator and the endotracheal tube. MEASUREMENTS AND MAIN RESULTS: Hemodynamic and gasometric variables were recorded before NO inhalation, during administration of inhaled NO (20 ppm, 20 mins), and 20 mins after NO discontinuation. Inhaled NO reduced pulmonary artery pressure from 26 +/- 6 to 22 +/- 5 mm Hg (p = .0004), but arterial oxygenation, cardiac output, and right ventricular ejection fraction remained unmodified (41% +/- 9% vs. 41% +/- 8%; not significant). Calculated pulmonary vascular resistance decreased from 453 +/- 233 to 348 +/- 108 dyne x sec/cm5 x m2 (p = .02), and right ventricular volumes did not change. Subsequently, right ventricular end-systolic pressure/volume ratio decreased from 0.52 +/- 0.22 to 0.44 +/- 0.19 mm Hg/mL/m2 (p = .01). No significant correlation was observed between the changes of pulmonary artery pressure (or pulmonary vascular resistance) and changes of right ventricular ejection fraction. CONCLUSION: Inhalation of NO does not seem to improve either right ventricular function or arterial oxygenation in patients with acute respiratory failure caused by acute exacerbation of COPD.

Administration, Inhalation↗
PubMed1998

Hemodynamic and inotropic effects of milrinone after heart transplantation in the setting of recipient pulmonary hypertension.

BACKGROUND: Right ventricular failure remains an important cause of early morbidity and death after heart transplantation and is commonly related to preexistent recipient chronic pulmonary hypertension, which occurs as a result of long-standing congestive heart failure. In this study, the hemodynamic and inotropic effects of milrinone were assessed after bicaval heart transplantation in the setting of monocrotaline pyrrole-induced recipient chronic pulmonary hypertension. METHODS: Twenty dogs were used for 10 successfully completed transplantation experiments. Recipient animals underwent right atrial injection of 3 mg/kg monocrotaline pyrrole 4 months before transplantation. Hemodynamic and functional data were taken 1 hour after termination of cardiopulmonary bypass and after milrinone infusion. Myocardial function was assessed with load-insensitive means (preload-recruitable stroke work) and pulmonary vascular impedance was calculated with Fourier analysis. RESULTS: At the time of transplantation, before cardiopulmonary bypass, pulmonary hemodynamic indexes in recipient animals were significantly increased when compared with donors and were further significantly increased after cardiopulmonary bypass. Two animals died after transplantation as a result of acute right ventricular failure. In surviving animals milrinone infusion led to significant increases in right ventricular function, which occurred in association with significant improvements in pulmonary vascular impedance and transpulmonary efficiency. CONCLUSIONS: In the setting of monocrotaline pyrrole-induced recipient pulmonary hypertension, milrinone was associated with significant improvements in pulmonary vascular impedance, right ventricular function, and transpulmonary efficiency. These data suggest that milrinone is an effective means to improve right ventricular dysfunction and pulmonary vascular efficiency after bicaval heart transplantation in the setting of recipient chronic pulmonary hypertension.

Animals↗