The effects of nebulized salbutamol on serum potassium concentration in bronchial asthmatics

Jee, Young Koo; Kweon, Suk Hoe; Lee, Key Young; Jang, In Jin

Abstract

BACKGROUND AND OBJECTIVE: The knowledge about the effects of the nebulized B2-agonist on serum potassium is limited. We aimed to assess the possible hypokalemia following nebulization of salbutamol. METHOD: Seven patients(mean age 60 +- 7.1years) with acute exacerbated asthma were treated with salbutamol nebulization(5mg nebulization at 1 hour interval, 3 times) without concomitant use of steroid or other bronchodilator such as theophylline.
RESULTS
There was a significant increase in FEV1, from 46.41+-25.91% at baseline to 62.86+-22.38% at 3 hours after treatment. Serum potassium concentration was significantly decreased, from 3.93+-0.58mEq/L at baseline to 3.41+-0.62mEq/L and 3.46+-0.53mEq/L at 1 hour and 3 hours after third nebulization, repectively. There was a significant prolongation of the QTc interval in EKG from 454.36+-27.07msec at baseline to 479.41+-35.64msec and 505.09+-58. 69msec at 1 hour and 3 hours after third nebulization, respectively. Serum salbutamol concentration was 4.18+-3.39ng/ml at baseline, and increased to 7.69+-6.94ng/ml and 9.84+10.34ng/ ml at 1 hour and 3 hours after treatment, respectively. Magnitude of the hypokalemia and the degree of prolongation of the electrocardiographic QTc interval were significantly correlated with the level of serum salbutamol concenturation.
CONCLUSION
The results suggest that cardiac complication could develop due to hypokalemia during repeated salbutamol nebulization. Caution should be done in monitoring of serum potassium concentration when using nebulized salbutamol repeatedly for the treatment of acute exacerbated bronchial asthma.