2003 OPEN FORUM Abstracts
Ability to achieve lung-protective ventilation goals when different modes are used with the NIH ARDS Network (ARDS-Net) protocol during clinical management of acute lung injury.
RH Kallet MS RRT, JM Luce MD, RM Jasmer MD. Departments of Anesthesia, and Pulmonary Critical Care Medicine, University of California, San Francisco at San Francisco General Hospital.
Background: We inquired whether clinician-use of the ARDS Net protocol could maintain the strict parameter regulations for lung-protective ventilation if different ventilator modes were utilized.
Methods: Two reference period ventilator status checks (00:00 and 12:00) on the first full day of ARDS-Net protocol management were used to assess achievement of lung-protective ventilation targets that we defined as VT < 6.5 mL/kg predicted body weight, Pplat < 30 cm H2O, PEEP/FiO2 settings per ARDS-Net protocol (without regard to oxygenation) and set respiratory rate (f) /pH within the range of < 35 with a pH > 7.30 and < 7.45. These definitions were slightly more liberal and less-complex than in the original ARDS-Net study. Differences between modes were analyzed by Kruskal-Wallis tests and Dunn's multiple comparison tests with alpha set at 0.05.
RESULTS: Three hundred forty-eight ventilator status checks were analyzed. Although 72% of ventilator status checks were on volume-control ventilation (VCV), 28% were on pressure-regulated volume control (PRVC), pressure control ventilation or airway pressure-release ventilation (APRV).
|VT||7.00 ± 1.82*||6.19 ± 0.65||6.07 ± 1.01|
|Pplat||34.6 ± 7.0*||25.7 ± 5.0||27.2 ± 6.8|
|PEEP||13.3 ± 3.6*||10.3 ± 2.6||9.5 ± 3.1|
|FiO2||0.77 ± 0.21*||0.58 ± 0.15||0.60 ± 0.18|
|RR||28.6 ± 7.0||27.4 ± 6.1||26.6 ± 7.5|
|pH||7.29 ± 0.10*||7.38 ± 0.07||7.37 ± 0.08|
|VT : Pplat||25%||60%||62%|
|RR : pH||80%||92%||85%|
*p<0.0001 compared to either VCV or PRVC
VT and Pplat were reasonably well maintained when either VCV or PRVC were used to manage patients on the ARDS-Net protocol. However, when analyzed in combination, the "on-target" rate was substantially lower. The deterioration in variable control with pure pressure-regulated modes may reflect in part their use in more severely-ill patients.
Conclusion: Clinician use of the ARDS Net protocol appears to yield percent-on target variable control less than what was achieved during the ARDS-Net study. However, mean VT and Pplat were within lung-protective ventilation targets.