Effects of heparin on hypertonic potassium chloride-induced bronchoconstriction.

BACKGROUND

Changes in bronchial osmolarity is a well-known factor for bronchoconstricion. Recenty, nonisotonic aerosols have begun to be used for the assessment of bronchial hyperreactivity. Hypertonic KCl can cause bronchoconstriction even in non-symptomatic asthmatic patients.

OBJECTIVE

To evaluate the protective role of heparin on hypertonic KCl-induced bronchospasm in asthma.

METHODS

Thirty-eight asthmatic patients were included in this double-blind, placebo-controlled study. On day 1 of the study, after performing the respiratory function test (RFT), patients had inhaled KCl 10% and RFTs were done after 20 minutes. On day 2 of the study, after the basal RFT, 18 patents inhaled NaCl 0.9% 0.2 mLkg solution. After the completion of this procedure, patients waited for 20 minutes and inhaled KCl 10% 10 mL, and RFTs were repeated 20 minutes later. The second group consisted of 20patients who inhaled heparn 1,000 units/kg after the RFTs were performed. Twenty minutes later, they inhaled KCl 10% and waited for 20 minutes. Finally, RFTs were done and compared with those from the other group.

RESULTS

In the control group, forced expiratory volume in one second (FEV1) decreased 17.4% on day 1 and 16.4% on day 2. In the heparin-treated group, FEV1 decreased 18.6% on day 1, but almost no change occurred after this group was treated with heparin before inhalation of hypertonic KCl on day 2.

CONCLUSIONS

Heparin was found to be highly protective against hypertonic KCl induced bronchospasm in bronchial asthma.