Combined effects of hypocapnia and nicardipine on airway resistance: a pilot study.

OBJECTIVE

The aim of this study was to investigate the modification of the resistive inspiratory properties of the respiratory system associated with hypocapnia in the presence of nicardipine.

METHODS

The resistance of the respiratory system, Rrsmin, was studied in two groups of patients who needed mechanical hyperventilation. Group 1 (n = 14; 47 years) was the control group (head injuries); group 2 (n = 12; 53.5 years) included patients treated over a 3 week period with nicardipine (0.5 microgram.kg-1.min-1 i.v.) to prevent arterial vasospasm after subarachnoid haemorrhage.

RESULTS

There was no statistical difference between the groups concerning anthropometric and basal respiratory characteristics. In group 1, hypocapnia caused a 20.9% increase in Rrsmin, but no significant increase was observed in group 2.

CONCLUSION

Hypocapnic alkalosis had a significant bronchial constrictory effect, which was eliminated in the presence of nicardipine hydrochloride.