Objective: To assess the effect of a long-acting inhaled beta 2-agonist, salmeterol (SM), compared to a short-acting inhaled beta 2-agonist, salbutamol (or albuterol, SB) on the occurrence of morning dip (MD) in patients recovering from an acute severe asthma attack (ASA).
Design: Prospective study.
Setting: 18-bed, medical intensive care unit (ICU) in a university hospital.
Patients: 19 patients suffering from an ASA.
Interventions: Serial measurements of the peak expiratory flow rate (PEFR), arterial blood gases, vital capacity and forced expiratory volume in one second (FEV1) were performed from admission. All patients were first treated with i.v. methyl prednisolone and i.v. SB. Once the PEFR was stable and > 35% of predicted value, i.v. SB was stopped while i.v. steroids were maintained, and patients were randomised to either inhaled SB (9 patients, 400 micrograms every 4 h) or inhaled SM (10 patients, 100 micrograms every 12 h).
Results: The mean admission PEFR was 26.1 +/- 11.7% of the predicted value and was not different between the two groups. MD was more frequent with SB (6/9 patients) than with SM (4/10). The severity of MD, expressed in l/min fall in PEFR, was higher in SB than in SM (106 +/- 25 vs 55 +/- 37; p < 0.05).
Discussion: MD is frequent in ASA. In ASA, SM appears to reduce the frequency and the severity of MD more than SB. The clinical implications of this observation, particularly a lowering of mortality and a shortening of the ICU stay, remain to be investigated.