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Background: Positive intrathoracic pressure reduces preload and afterload by decreasing left ventricular (LV) transmural pressure which in turn can increase LV ejection fraction. Continuous positive airway pressure (CPAP) administered via face or nasal mask can augment cardiac output in patients with congestive heart failure (CHF), but the clinical usefulness of CPAP as a nonpharmacological method of therapy in these patients needs to be further studied .
Methods: Nasal CPAP was applied to 21 patients (13 male, 8 female, mean age 6513 yrs ) with low LV ejection fraction (288 %) who were under standart heart failure treatment. The etiology of CHF was ischemic heart disease in 15 patients and idiopathic dilated cardiomyopathy in 6. Twelve of the patients were in NYHA Class II and 9 were in III. Baseline blood pressure (BP), heart rate (HR), respiratory rate (RR), oxygen saturation (SpO2) values were noted. After the measurement of cardiac output (CO) and cardiac index (CI) by Doppler echocardiography, nasal CPAP (8 cm H2O) wasapplied for 10 minutes to the patients . All the measurements were repeated at the end of this period while on CPAP.
Results: CPAP was tolerated by all of the patients.There was no significant change in HR (8218 /min vs. 8318/min) and diastolic BP(6315 mmHg vs. 6818mmHg), but a slight elevation in systolic BP (11323 mmHg vs. 12029mmHg) (p<0.02) was observed.Respiratory rate decreased from 244/min to 212/ min (p=0.0001), and oxygen saturation increased from 935% to 954% (p=0.01). CO (3.71.0 vs. 4.01.0 lt/min) (p=0.02) and CI (2.20.6 vs. 2.40.6 lt/min/m2) (p=0.04) increased significantly.
Conclusions: CPAP improves LV function and some of the respiratory parameters in patients with chronic CHF. Thus, it may be useful as an adjunct to medical therapy of syptomatic patients with CHF.