Introduction There is limited research into airway clearance techniques (ACT) and high dose hypertonic saline 7% (HS-7) tolerance and safety in adults with severe asthma. Clinical benefit of sputum eosinophils and microbiology in severe asthma is well established. Airway samples can be obtained via spontaneous production, using physiotherapy (ACT, sputum induction (0.9–4.5% traditionally) or via bronchoscope.1 There are concerns with regards to risk of asthma exacerbation with sputum induction and bronchoscopy.
Objective assess and compare safety and efficacy of ACT, HS-7 and bronchoscopy in patients attending severe asthma clinic.
Method We assessed consecutive patients attending a severe asthma service at a tertiary referral centre who had undergone ACT and or HS-7 challenge and or bronchoscopy during 2014–2016. In total, 330 procedures were performed by a chest physiotherapist (ACT/HS-7) and consultant respiratory physician (bronchoscopy). Data was gathered on procedure tolerance and sample yield. Indications for undergoing HS-7 included sample procurement or challenge test for home nebulisation. Bronchoscopy was performed for a variety of indications, not limited solely to sample procurement.
Results 114 patients completed ACT, 109 underwent HS-7 and 99 had bronchoscopy (Table 1). 65 of 104 (62.5%) in the physiotherapy group had no prior spontaneous sputum samples. Of these, 46 (71%) had HS-7 induction and 19 (29%) had successful ACT. 25 of 77 (32%) patients in the physiotherapy group had positive bacterial culture, and 18 of 38 (47%) positive aspergillus PCR. ACT, HS-7 and bronchoscopy were well tolerated. All 114 (100%) patients tolerated ACT from an asthma perspective. 8 of 117 (7%) of HS-7 group and 8 of 99 (8%) of bronchoscopy group required rescue salbutamol nebulisation without further complications. Two patients had severe asthma exacerbations in the bronchoscopy group, 2 of 99 (2%), and required hospitalisation at ward level, This risk was similar to previously reported data.
Conclusion In patients attending a severe asthma clinic physiotherapy techniques (ACT and HS-7) were safe and effective. Bronchoscopy had similar requirement for rescue salbutamol nebulisation compared to HS-7, but a higher risk (2%) of severe asthma exacerbation.
Brinke AT, et al. Sputum induction in severe asthma by standardised protocol. AJRCCM 2001;164(5):749–753.