Patients with pulmonary hypertension (PH) have a cardiac limitation characterized by the agency of a decreased resting stroke index (SI) and an inability to augment misfortune volume with exercise.

Patients with pulmonary hypertension (PH) have a cardiac limitation characterized by the agency of a decreased resting stroke index (SI) and an inability to augment misfortune volume with exercise. We experimented the hypothesis that a noninvasive estimation of SI, either at repose or with exercise, could be used to identify the vicinity and severity of PH. We used the inert gas rebreathing technique for measuring cardiac output and SI in nine subdues with PH and seven regulate subjects without pulmonary vascular disease. Noninvasive measurement of SI was compared with invasive measurement of pulmonary artery press (PAP), pulmonary vascular resistance index (PVRI), and SI. Inert gas estimation of cardiac output correlated well with invasive measurements (r=094) All PH subdues had a depressed resting SI while all sway subjects had a normal resting SI. An inverse correlation between the SI measured by means of inert gas technique and mean PAP was seen with the two rest (r=-0.86) and exercise (r=-079) Because the resting SI differentiated controls with PH from controls and correlated with disease severity, exercise measurements were not required. Multiple serial measurements performed in brace PH subjects while receiving prostacyclin infusion produc a high of the same height of correlation between the inert gas SI and mean pulmonary artery press We conclude that inert gas measurement of SI may conduce to a useful role in the diagnosis and management of patients with PH

(Chest 1994; 106:59-66)

In=natural logarithm;

PH=pulmonary hypertension;

PAP=pulmonary artery pressure;

PAOP=pulmonary artery occlusion pressure;

PVR=pulmonary vascular resistance;

PVRI=pulmonary vascular resistance index;

SEM%=SEM/average cardiac output;

SI=stroke index

Pulmonary hypertension is a diagnosis ofttimes considered in clinical practice, still frequently unconfirmed due to the invasive nature of the diagnostic techniques required for confirmation and the used by all belief that there are no effective therapeutic interventions. Many cases of pulmonary hypertension (PH) are not diagnosed until stiff symptoms or obvious physical findings are at hand usually indicating advanced disease. While routine pulmonary function examples are useful in the diagnosis of diseases of the airways and lung parenchyma, they are of little diagnostic value in pulmonary vascular disease. Pulmonary function in exposes with primary PH generally attend tos to be normal or associated with either a mild restrictive pattern or a decrease in carbon monoxide diffusing capacity.(1)

A noninvasive example or series of tests which could identify the appearance of pulmonary vascular disease and quantify its severity would be extremely useful clinically. Echocardiography has been used to estimate pulmonary artery press (PAP) through the analysis of regurgitant house flow at either the tricuspid or pulmonary valves. Unfortunately, the detection of regurgitant arise and accurate measurement of regurgitant velocity is repeatedly impossible in subjects with relatively mild disease.(2)(3)(4) Chronic obstructive pulmonary disease and obesity posture technical difficulties, further limiting its accuracy and utility.

enthralls with PH generally have a cardiac dysfunction at tranquillity characterized by decreased SI.(5)(6)(7)(8) They have also been shown to have an abnormal answer to exercise, with a reduc ability to increase SI.(6) Therefore, any increase in cardiac output with exercise is largely heart rate hanging We speculated that a noninvasive measurement of SI at peacefulness and on exercise would be a useful screening standard for PH, and we used the soluble inert gas rebreathing technique to proof this hypothesis.

METHODS

Subjects

couple groups of subjects underwent hemodynamic evaluation using standard pulmonary artery catheter measurements and the inert gas rebreathing technique. The first cluster consisted of nine subjects (four men age range 30-76 years) with primary PH or scleroderma with stern pulmonary vascular involvement who were undergoing evaluation for vasodilator therapy or lung transplantation (Table 1) The make subordinates with scleroderma had normal chest radiographs with abnormal comput tomography (CT) appearance or radiographic evidence of mild interstitial lung disease with disproportionately harsh PH and a history of characteristic skin lesions, Raynaud's phenomenon or as well-as; not only-but also; not only-but; not alone-but Valvular and congenital heart diseases were exclud by dint of echocardiography and cardiac catheterization. Thromboembolic disease was exclud according to a normal ventilation-perfusion scan or pulmonary angiography. The severity of PH in this assign places to ranged from relatively mild to severe

[TABULAR DATA OMITTED]

A next to the first reference group of seven bring under rules without pulmonary vascular disease (four men age range 55-78 years) was also studied. These controls were without pulmonary disease by means of history or pulmonary function testing and had no evidence of significant cardiac or coronary artery disease by means of history or coronary angiography. The rule group also included subjects requiring pulmonary artery catheterization for routine perioperative management, or the evaluation of turn status in acute renal failure.

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