The effect of nebulized salbutamol on atrial electrical properties in mechanically ventilated critically ill patients - a randomized, double-blind study.

BACKGROUND: Salbutamol is a short acting beta-2 mimetic commonly used among intensive care unit patients. There are data suggesting that his mechanism of action can be a potential factor triggering arrhythmias. The aim of this study was to assess whether nebulized salbutamol causes systemic effects resulting in electrocardiographic alterations associated with atrial fibrillation occurrence in mechanically ventilated patients.

METHODS: 50 individuals were randomly allocated to receive either 2.5 or 5 mg of nebulized salbutamol for 20 minutes. 60 minutes prior to the start of nebulization, 12 lead surface electrocardiogram has been recorded. Electrocardiographic parameters associated with atrial activity - P wave and PR interval, and their derivates: P wave dispersion and PR interval dispersion were analysed.

RESULTS: Both doses of inhaled salbutamol caused changes of P wave indices - maximal, minimal and mean P wave duration, from simultaneously recorded leads, and concomitant decrease of P wave dispersion. Prolongation of P wave affected predominantly minimal P wave duration (11.93 ms [95% CI: 8.69-15.17]) comparing with maximal P wave duration (2.61 [95% CI: 021-5.43]). Atrio-ventricular conduction - PR interval was also prolonged, however minimal PR interval duration from simultaneously recorded leads was shortened in group receiving 5 mg of salbutamol.

CONCLUSIONS: Nebulized salbutamol in ICU patient possess systemic effects which causes changes in P wave indices in surface ECG recordings. This electrophysiological influence may be associated with the increased risk of atrial fibrillation among this group of patients.