Hirshberg, Eliotte L.;
Lanspa, Michael J.; Peterson, Juhee; Carpenter, Lori; Wilson, Emily L.; Brown,
Samuel M.; Dean, Nathan C.; Orme, James; Grissom, Colin K.
Objectives: Low
tidal volume (= tidal volume ≤ 6 mL/kg, predicted body weight) ventilation
using volume control benefits patients with acute respiratory distress
syndrome. Airway pressure release ventilation is an alternative to low tidal
volume-volume control ventilation, but the release breaths generated are
variable and can exceed tidal volume breaths of low tidal volume-volume
control. We evaluate the application of a low tidal volume-compatible airway
pressure release ventilation protocol that manages release volumes on both
clinical and feasibility endpoints.
Design: We
designed a prospective randomized trial in patients with acute hypoxemic
respiratory failure. We randomized patients to low tidal volume-volume control,
low tidal volume-airway pressure release ventilation, and traditional airway
pressure release ventilation with a planned enrollment of 246 patients. The
study was stopped early because of low enrollment and inability to consistently
achieve tidal volumes less than 6.5 mL/kg in the low tidal volume-airway
pressure release ventilation arm. Although the primary clinical study endpoint
was PaO2/FIO2 on study day 3, we highlight the feasibility outcomes related to
tidal volumes in both arms. Setting: Four Intermountain Healthcare tertiary
ICUs.
Patients: Adult
ICU patients with hypoxemic respiratory failure anticipated to require
prolonged mechanical ventilation. Interventions: Low tidal volume-volume
control, airway pressure release ventilation, and low tidal volume-airway
pressure release ventilation.
Measurements and Main Results: We observed wide variability and higher tidal
(release for airway pressure release ventilation) volumes in both airway
pressure release ventilation (8.6 mL/kg; 95% CI, 7.8–9.6) and low tidal
volume-airway pressure release ventilation (8.0; 95% CI, 7.3–8.9) than volume
control (6.8; 95% CI, 6.2–7.5; p = 0.005) with no difference between airway
pressure release ventilation and low tidal volume-airway pressure release
ventilation (p = 0.58). Recognizing the limitations of small sample size, we
observed no difference in 52 patients in day 3 PaO2/ FIO2 (p = 0.92). We also
observed no significant difference between arms in sedation, vasoactive
medications, or occurrence of pneumothorax.
Conclusions:
Airway pressure release ventilation resulted in release volumes often exceeding
12 mL/kg despite a protocol designed to target low tidal volume ventilation.
Current airway pressure release ventilation protocols are unable to achieve
consistent and reproducible delivery of low tidal volume ventilation goals. A
large-scale efficacy trial of low tidal volume-airway pressure release
ventilation is not feasible at this time in the absence of an explicit,
generalizable, and reproducible low tidal volume-airway pressure release
ventilation protocol.
No comments:
Post a Comment