The Science Journal of the American Association for Respiratory Care

2008 OPEN FORUM Abstracts

NON INVASIVE VENTILATION IN ACUTE ASTHMA: A RANDOMIZED CONTROL TRIAL

Dheeraj Gupta1, Alok Nath1 Ritesh Agarwal1, Digamber Behera1



Background: Non invasive positive pressure ventilation (NIPPV) has emerged as an important modality of management in patients with selected causes of acute respiratory failure (ARF). Its role in acute asthma (AA) however is not well defined.

Objective:
To evaluate the efficacy of NIPPV in AA in a respiratory intensive care unit (RICU) in North India. Methods: Patients with a clinical diagnosis of acute asthma were openly randomized to either optimal medical therapy (OMT) or NIPPV. The primary outcome measures were time to improvement in forced expiratory volume in the first second (FEV1) and/or peak expiratory flow (PEF) by at least 50%, ICU and hospital length of stay and need for endotracheal intubation. Secondary outcome measures were rate of improvement in clinical (respiratory rate [RR]), spirometric (PEF and FEV1) and gas exchange parameters (pH, PaO2-FiO2 ratio, PaCO2), requirement of oxygen and medications.

Results:
Of the 337 ICU admissions during the study period,53 had AA and 28 and 25 patients were randomized to NIPPV and OMT respectively. The baseline parameters were similar in the two groups except for the mean duration of asthma, which, was shorter in the OMT group. The median inspiratory positive airway pressure and expiratory positive airway pressure used was 12 and 5 cm H20 respectively. The mean time to achieve the primary end point was similar in both the groups (1.7 vs. 1.9 hours, p=0.55, Mann-Whitney U test). There was a significant improvement in RR, PEF, FEV1 and PaO2-FiO2 (but not pH and PaCO2) in both the groups, however there was no difference between the two groups (MANOVA). The mean doses of inhaled levosalbutamol (42.8 vs. 31.2 mg; p=0.0001) and ipratropium (7568.2 vs. 5203.2 mcg; p=0.0001) were significantly lesser in the NIPPV group. The mean length of ICU (27.1 vs.16.5 hours) and hospital stay (62.9 vs.43.6 hours) was also significantly shorter (figure) in the NIPPV group (p= 0.0001). There were four instances of OMT failure and all these patients improved with NIPPV. Two patients in the NIPPV arm required mechanical ventilation. There was no mortality in either of the arms.

Conclusions:
NIPPV may be potentially beneficial in carefully selected and monitored patients with AA.