The relationship between cardiac output and posthyperventilation hyperpnoea in patients with essential hypertension.
Eur Respir J
; 12(5): 1160-3, 1998 Nov.
Article
em En
| MEDLINE
| ID: mdl-9864014
ABSTRACT
Posthyperventilation hyperpnoea (PHVH) is the progressive decline in minute ventilation (V'E) that follows abrupt cessation of voluntary hyperventilation. It has been hypothesized that the increase in cardiac output (CO) during hyperventilation could contribute to the duration of PHVH. This hypothesis was tested by measuring the duration of PHVH in patients with essential hypertension, in whom the increase in CO as a result of various stimuli is less pronounced. Twenty male hypertensives (mean arterial blood pressure+/-SEM 178/ 107+/-3/1 mmHg), and 12 age-matched male healthy subjects were studied. The study consisted of three periods control (5 min), voluntary hyperventilation (2 min), and recovery (3 min). V'E, CO, end-tidal CO2 and O2 tensions were measured, and the time constant (tau) of the V'E decay during recovery calculated. The V'E decay was faster in hypertensives (tau 0-8.4 s) than in healthy subjects (tau 12-59 s; p<0.01). During voluntary hyperventilation, CO increased to a lesser extent in hypertensives (6.8+0.7 L.min(-1)) than in healthy subjects (12.9+/-1.1 L.min(-1); p<0.01). In hypertensives, changes in CO during voluntary hyperventilation were significantly related to tau (r=0.646; n=20; p=0.002). The less pronounced rise in cardiac output during hyperventilation in hypertensives could account for the shorter duration of posthyperventilation hyperpnoea.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Respiração
/
Débito Cardíaco
/
Hipertensão
/
Hiperventilação
Limite:
Adult
/
Humans
/
Male
/
Middle aged
Idioma:
En
Revista:
Eur Respir J
Ano de publicação:
1998
Tipo de documento:
Article