MDI or nebulization in moderate to severe COVID-19 disease with COPD: which one is better?

Abstract

Introduction: Aerosol bronchodilator therapy via nebulization, using a nebulizer or metered-dose inhaler (MDI) with a spacer device or dry powder inhaler is the mainstay in the treatment of COPD. We, herein, discuss two such cases with corresponding concerns related to various modes of bronchodilation in moderate to severe COVID-19 patients with COPD. Two COVID-19 patients (60 years/M and 55 years/M) with COPD presented with worsening fever, cough, and shortness of breath for around 10 days. Chest radiographs revealed mid and lower lung zone involvement in both. Both received tazobactam-piperacillin, teicoplanin, ivermectin, hydroxychloroquine, enoxaparin, dexamethasone, salmeterol MDI, multivitamin, and received oxygen via high FiO2 non-rebreathing mask and maintained 92 to 94% oxygen saturation and 24 to 32 breaths/minute. We observed their inability to attain an optimal peak inspiration with MDI and thus increased the dose to @ 4 to 6 puffs. Following no improvement, nebulization was started. With the improvement in peak inspiratory flow rate, the MDIs were reinstituted. The pulmonary symptoms improved and both the patients were discharged subsequently. Discussions: Bronchodilator delivery by MDI or wet nebulizer is equivalent in the acute treatment of adults with airflow obstruction. 1 A Cochrane review 2 observed no significant difference in FEV1 at 1 hour after dosing between nebulization and MDI; however, an improved FEV1 trend was observed with nebulization.2 In critically ill patients, nebulization is preferred over MDI or DPI as the latter needs an optimal peak inspiratory flow rate (∼60 L/minute) which is often compromised in critical illness. During the COVID pandemic, bronchodilation via nebulization has got a serious concern, i.e., the nebulizers produce small- and medium-size aerosol range and can disperse viral particles in exhaled air >0.8 m from the patient and remain airborne for more than 30 minutes.3 Thus, a potential exposure threat to healthcare workers (HCW). It should preferably be provided in isolation within negative pressure rooms with providers donning all personal protective equipment. The expert consensus guidelines recommend replacing nebulization with MDIs in COVID-19 disease; however, no dogmatic guidelines or protocols in this context.4 As far as pathophysiology is concerned, COPD is an obstructive airway pathology characterized by expiratory airflow limitation due to chronic inflammation of the large central airways, peripheral bronchioles, and destruction of lung parenchyma. On the contrary, in COVID-19, Mu et al. observed it to be primarily a restrictive ventilatory defect along with impairment of diffusion capacity as reflected by the pulmonary function tests in 110 discharged survivors with COVID-19.5 Therefore, COVID patients with COPD may present with mixed pattern (obstructive and restrictive) which may affect the performance of the aforementioned modes of bronchodilation. Conclusion: We emphasize the need for assessing the risk-benefit ratio related to the safety of HCW with the use of MDI plus spacer vs the risk of clinical deterioration by avoiding nebulization in patients with COVID-19 disease with COPD. We also recommend the need for further research and evidence-based concrete guidelines in context to the favorable mode of inhaled bronchodilator in COVID-19 disease.