Effect of Aerosolised Salbutamol Administration on Arterial Potassium Concentration in Anaesthetised Horses

Aerosolized salbutamol has been associated with hypokalemia in horses undergoing colic surgery. The objective of this study was to evaluate the effect of aerosolized salbutamol on arterial potassium concentration ([K +]) in healthy anaesthetized horses undergoing elective surgery. Anesthetic records were reviewed from healthy adult horses undergoing elective surgery over a 3-year period with two complete sets of arterial electrolyte (sodium [Na +], potassium [K +], chloride [Cl -], calcium [Ca 2+]) concentration measurements. Records were excluded if intra-operative electrolyte supplementation, antimicrobial administration or noncrystalloid fluid administration were documented or if salbutamol was administered prior to electrolyte measurement. Sixty records which fulfilled inclusion criteria were divided into two groups depending on whether or not aerosolized salbutamol (2μg kg -1) (to treat hypoxemia) was administered after baseline electrolyte measurement and before the second electrolyte measurement. Aerosolized salbutamol was administered (Group S) in 22 horses and not administered (group NS) in 38 horses. There was a significant reduction in [K +] and [Ca 2+] between baseline and the second electrolyte measurement in both groups (P< .001). The reduction in [K +] between baseline and the second electrolyte measurement was significantly greater in group S (12.3%) compared to group NS (6.9%) (P= .017) and was significantly associated with salbutamol administration (P= .04). The results of this study indicate that monitoring [K +] is important in anaesthetized horses, particularly after aerosolized salbutamol administration.