Daily Requirement of Oxygen to Reverse Pulmonary Hypertension in Patients with Chronic Bronchitis

Abstract

SummaryWe have shown previously in patients with chronic bronchitis that correction of the hypoxaemia by continuous administration of oxygen substantially reduced the pulmonary hypertension by reversal of structural changes in the pulmonary resistance vessels. We have now demonstrated that such improvements may occur with less than continuous oxygen. Treatment with oxygen for 18 hours daily significantly decreased pulmonary arterial pressure and pulmonary vascular resistance. Oxygen therapy for 15 hours a day also decreased pulmonary vascular resistance; such a regimen is practicable in the home, is consistent with a working day free from the constraints of an oxygen supply, and should reduce the number of episodes of congestive cardiac failure. IntroductionPatients who are chronically hypoxaemic because of chronic bronchitis frequently develop pulmonary hypertension. This leads to right ventricular hypertrophy and right ventricular failure. In these patients the cardiac failure becomes a major part of their disability, and its presence carries a particularlypoor prognosis. Of a large series of patients with chronic

Effect of Lung Volume Reduction Surgery on Resting Pulmonary Hemodynamics in Severe Emphysema

“…We attempted to answer three questions: (1 ) What effect does LVRS have on resting pulmonary hemodynamics as compared with medical therapy, (2 ) What is the relationship between changes in lung function to changes in pulmonary hemodynamics after LVRS, and (3 ) What is the relationship between hemodynamic changes after LVRS and the changes that occur during exercise testing?…”

“…tion with decreased cross-sectional area of the pulmonary vasculature, may increase pulmonary vascular resistance (PVR) (2)(3)(4)(5). Hyperinflation may impair left (LV) or right ventricular (RV) diastolic filling (6)(7)(8)(9).…”

Provision of long term oxygen therapy.

“…Adequate oxygenation is achieved in the majority of subjects with a flow of [1][2][3] 14 patients.23 Moreover, in the NWRHA trial the frequency distribution of the number of hours per day that patients used their concentrators was negatively skewed; indeed six of the 76 patients were using their machines for less than six hours a day. Thus it appears that, if the necessary minimum daily duration of oxygen therapy for improved survival to accrue is in fact 15 hours,6 and the findings of the NWRHA study are representative of patient compliance in this country, then over half of the recipients will be having insufficient treatment.…”

“…For this purpose, according to the best available evidence, controlled oxygen supplements are required by the patient for a total of between 12 and 24 hours daily. [3][4][5][6][7][8] It is with such long term oxygen therapy (LTOT) that we are concerned here.…”

The Story of Oxygen

“…Stark et al demonstrated in 1972 that as little as 12-15 hours of oxygen a day improved hemodynamics as effectively as 24 hours of oxygen use. 22 These findings created the ethical equipoise to propose multicenter trials to test the effects of duration of oxygen therapy on patient outcomes.…”