A NOVEL EQUATION SUCCESSFULLY CALCULATES TIDAL VOLUMES FOR LUNG PROTECTIVE VENTILATION

Abstract

BackgroundEarly application of low-tidal-volume ventilation (LTVV) has been associated with improved outcomes in the emergency department (ED) and intensive care unit (ICU), but is not consistently applied. The perceived complexity of calculating an ideal body weight (IBW)-based tidal volume (Vt) may contribute to this disparity. We hypothesized that a simplified equation could successfully predict LTVV. ObjectiveTo create a memorable, single-step, sex-independent equation to estimate LTVV based on height. MethodsWe conducted a retrospective observational cohort study of patients who received mechanical ventilation (MV) at 2 EDs from January 2016 to June 2019. Data were abstracted by automatic query. Patients < 18 years old, < 60 inches in height, and with implausible or incomplete data were excluded. LTVV was defined as ≤ 8 mL/kg IBW. We created a formula predicting a 6–8-mL/kg IBW Vt. We applied this formula to a population of ICU patients in the same health care system who received MV from January 2017 to December 2019 using the same exclusion criteria. The outcome was whether the equation predicted a 6–8-mL/kg IBW Vt. ResultsA total of 982 ED patients were included; 753 (76.7%) had an initial Vt < 8 mL/kg IBW. The equation Vt = 20*(Ht-60) + 300 was derived. A total of 3720 ICU patients were included. The Vt equation successfully predicted a Vt of 6–8 mL/kg IBW in 3720 (100%) of ICU patients. ConclusionsA novel equation successfully predicted a 6–8-mL/kg IBW Vt in a cohort of patients with height ≥ 60 inches.