Simple Instructions for using Pressurized Aerosol Bronchodilators¹

Abstract

Although the manufacturers of pressurized aerosol bonchodilators issue instructions for using the inhalers, little or no experimental verification exists. Bronchodilatation has been measured after controlled inhalations of 500 μg terbutaline sulphate given in a systematic series of investigations to 8 patients with reversible airways obstruction at 2 different inhalation flow rates (25 1/min and 80 1/min), 3 different lung volumes (20%, 50% and 80% vital capacity) and followed by 2 different breath-holding pauses (4 and 10 seconds). The results indicate that patients may release the aerosol at any time during the course of a slow deep inhalation which should be followed by 10 seconds of breath-holding. This will ensure an optimal bronchodilator response.

Systemic beta‐adrenoceptor responses to salbutamol given by metered‐ dose inhaler alone and with pear shaped spacer attachment: comparison of electrocardiographic, hypokalaemic and haemodynamic effects.

“…Dose increments were made every 20 min as follows : 100 ,ug, 200 ,ug, 500 ,ug, 1000 ,ug, 2000 ,ug. Specially prepared metered-dose aerosol canisters were used delivering either 100 ,ug or 500 ,ug salbutamol per actuation, to arrive at the desired dose (Glaxo Group Research, Greenford). Previous instruction had been given in correct use of an MDI or PSS, using the methods described by Newman et al (1980) and Gleeson & Price (1988) respectively. For the MDI, this involved deep slow inhalation from residual volume to total lung capacity, followed by 10 s breath-holding.…”

Airway deposition and airway effects of antiasthma drugs delivered from metered-dose inhalers

“…In accordance with the dependency of the airway deposition on the mode of inhalation, the effects elicited are dependent on the way the patient uses the inhalation system. NEWMAN and co-workers [79,80] performed a number of studies on terbutaline pMDI in order to evaluate the effects of different modes of inhalation on airway deposition and change in forced expiratory volume in one second (FEV1). A slow (30 L·min -1 ) inhalation of 500 µg terbutaline sulphate from a pMDI increased FEV1 by about 30%, but a fast (80 L·min -1 ) inhalation increased FEV1 by only about 15%.…”

Aerosol therapy in childhood asthma

“…Como a dose é liberada de uma vez só, o paciente tem que inalá-la também em uma só inspiração; esta deve ser lenta e profunda. É necessário um sincronismo entre o disparo da dose e a inspiração: o paciente deve iniciar uma inspiração; logo depois de iniciá-la, deve acionar o aparelho e continuar inalando, lentamente 9,12,13 , até atingir a capacidade vital. Deve então manter por 10 segundos uma pausa respiratória e só depois expirar.…”

“…9. Equivalência entre doses Um grande número de fatores interfere sobre a eficácia das drogas inaladas 1,7,9,10,12,13 . O quadro abaixo mostra a influência e a interrelação dos principais fatores.…”