Cardiorespiratory and glycaemic changes following prehospital nebulised salbutamol in acute asthma: a mixed retrospective and prospective observational study

Purpose: In 2010, the Global Strategy for Asthma Management and Prevention recommended reducing the reliance on treating acute asthma exacerbations with short-acting β2 agonists (SABAs) given potential adverse effects. However, more than a decade later, SABAs, particularly nebulised salbutamol, remain at the forefront of acute asthma care. This study examined the physiological effects of nebulised salbutamol in patients experiencing moderate to severe asthma exacerbations.

Methods: A six month, prospective and retrospective observational study was undertaken involving prehospital asthma patients treated with nebulised salbutamol. Data were analysed using descriptive and inferential statistics, including paired comparisons and exploratory subgroup analyses, to identify relevant trends and variability.

Results: Among 176 eligible patients, reductions were observed in heart rate (mean − 3 beats/min) and respiratory rate (mean − 5 breaths/min), with modest improvement in peripheral oxygen saturation (+2%). Capillary blood glucose (CBG) analysis was conducted on a small prospective subgroup (n=8). A mean increase of +0.375 mmol/L was observed. When one clinically atypical outlier was excluded (n=7), the increase reached statistical significance. Albeit interpretation is limited by the small sample size.

Conclusion: Administration of ≥ 5mg nebulised salbutamol in acute asthma exacerbations was transiently associated with improved peripheral oxygen saturation and respiratory parameter changes during the prehospital treatment period. No clinically significant increase in heart rate was observed overall. A small rise in CBG was observed in a small prospectively monitored subgroup. However, the clinical significance of this finding remains uncertain. Larger, adequately powered prospective studies are required to confirm these findings. The present findings are insufficient to recommend changes to current glucose monitoring practices in non-diabetic patients.