Chest
Variability of the Pulmonary Vascular Response to Acute Hypoxia in Chronic Bronchitis
Section snippets
Patients
Twenty six patients with chronic bronchitis defined according to the criteria of the American Thoracic Society14 were included in the study. They all had chronic airway obstruction defined by a ratio FEV1/vital capacity <65 percent. They were investigated in a stable state of the disease: no acute exacerbation for at least two months; stability of arterial blood gas levels, FEV1 and weight during a control period of three weeks. Patients with asthma or whose FEV1 improved markedly (>30 percent)
RESULTS
Changes in arterial blood gas values, ventilatory, and circulatory variables are shown in Tables 2 and 3. All the variables, except the A/ E ratio, returned to the control level after the first hypoxic period (n = 19 patients). The difference in A/ E between the two control periods was, however, of small magnitude. Thus, the first hypoxic period had almost no residual effects detectable after the “wash-out” free interval of 20 minutes.
On average, ventilation
DISCUSSION
The results of this study suggest the following: (1) the pulmonary vascular response to hypoxia is rather modest, as a mean, in chronic bronchitis patients; (2) the magnitude of the response is related to the degree of acute hypoxia; and (3) there is a wide variability of the pulmonary vascular response ranging from no response at all to a marked elevation of PA, driving pressure, and PVR.
The response to acute hypoxia was rather modest if one considers the average figures: with the
ACKNOWLEDGMENT
The writers wish to thank F. Poincelot for technical assistance, B. Clément for typing the manuscript, and M. C. Rohrer for drawing the figures.
REFERENCES (28)
- et al.
Reversal of high altitude pulmonary hypertension
Am J Cardiol
(1966) - et al.
Cardiopulmonary hemodynamics during sleep in subjects with chronic obstructive pulmonary disease
Chest
(1984) - et al.
The influence of short periods of induced acute hypoxia upon pulmonary artery pressure in man
Am J Physiol
(1947) - et al.
Effects of acute anoxia on the circulation and respiration in patients with chronic pulmonary disease studied during the steady state
J Clin Invest
(1952) - et al.
Acute hypoxic responses
- et al.
Experimental models of pulmonary hypertension
- et al.
Lung vascular smooth muscle as determinant of pulmonary hypertension at high altitude
Am J Physiol
(1975) - et al.
Vascular hypertrophy in cattle susceptible to pulmonary hypertensioa
J Appl Physiol
(1979) - et al.
Variability of hypoxic pulmonary vasoconstriction in sheep
Am Rev Respir Dis
(1983) - et al.
Collateral ventilation may protect against high altitude pulmonary hypertension
J Appl Physiol
(1981)
Role of collateral ventilation in ventilation-perfusion balance
J Appl Physiol
High altitude pulmonary hypertension and pulmonary edema
La circulation pulmonaire du natif de haute altitude à La Paz (3700 m)
Chronic bronchitis and emphysema: the search for their natural history
Cited by (0)
This study has been partially supported by a grant of the “Fonds spécial des comités aépartementaux contre la tuberculose et les maladies respiratories” (Paris, France) No 84-MR/15.
revision accepted March 8.