A55-12 Scoping Review of the Literature: The Evolution of Tidal Volume Recommendations in Obstructive Lung Disease

Introduction The optimal strategy for mechanical ventilation in patients with obstructive lung disease remains poorly defined. We did a scoping review of the literature to define the ventilator settings based on existing research and reviews. Methods The study protocol and search strategy are registered on Open Science Framework. MEDLINE, Cochrane Central Register of Controlled Trials and Embase were queried using specific terms relevant to invasive mechanical ventilation in patients with obstructive lung disease. Results were limited to English articles and adult subjects. Articles based in peri-operative setting, weaning phase or intubation, were excluded. We reported in the PRISMA system. After removing duplicates, 4489 articles were screened from which 179 articles were reviewed in a Delphi process and 66 articles were included in the final review. We reviewed the literature commenting on all ventilator settings, but here we report the results pertaining to tidal volume (ml/kg ideal body weight). Results 41 articles mentioned tidal volumes while 25 out of 66 (38%) articles did not have any recommended tidal volume strategy and 37 articles (56%) were reviews or expert opinions. The only RCT, published in 2002, used a tidal volume of 10 to 15 ml/kg IBW. The sole systematic review, published in 2009, recommended a tight range of 7-8 ml/kg IBW. 21 articles (40.9%) recommended tidal volumes of 6 to 8 ml/kg IBW. There was significant variability in recommendations, and temporal trends were also noted. Since year 2000, there were more articles recommending lower tidal volumes, and total number of articles on the topic also decreased. Conclusions There is a gap in the evidence of mechanical ventilation in obstructive lung disease. Literature is mostly expert recommendations and not research studies. A trend of recommending lower tidal volumes was noted from year 2000, likely reflecting literature from ARDS - a separate disease state from obstructive lung disease.