Cardiac output and blood pressure in asthmatic children before and during induced asthma

The acute circulatory effects of asthma have been studied in two groups of children, having an average age of 13.2 and 14.7 years, respectively. Asthma was provoked by exercise (EIA group) and histamine inhalation (HIA group). The latter group was also studied after subsequent inhalation of a beta 2 receptor agonist. Cardiac output was measured by dye dilution and intraarterial blood pressure was recorded. During attacks of asthma cardiac output and heart rate increased in both groups (p less than 0.05). The stroke volume decreased in the EIA group (p less than 0.01) but remained unchanged in the HIA group. The systemic vascular resistance (SVR) did not change. After salbutamol inhalation, the cardiac output and stroke volume increased and the SVR decreased (all p less than 0.05). The hemodynamic response during exercise was normal. Thus asthmatic children have normal cardiovascular function during moderate asthma. The decrease in stroke volume in the EIA group depended presumably on the preceding exercise test. The response to the beta 2-stimulation was similar to that seen in healthy adults.