2003 OPEN FORUM Abstracts
CLINICAL IMPLEMENTATION OF THE NIH ACUTE RESPIRATORY DISTRESS SYNDROME NETWORK?S (ARDS-Net) LOW TIDAL VOLUME (VT) PROTOCOL REDUCES HOSPITAL MORTALITY COMPARED TO HISTORICAL CONTROLS.
RH Kallet MS RRT, JM Luce MD, RM Jasmer MD, JF Tang MD, AR Campbell MD, R Dicker MD, C Hemphill MD, J-F Pittet MD Departments of Anesthesia, Surgery, Neurology and Pulmonary Critical Care Medicine, San Francisco General Hospital (SFGH)
Background: The NIH ARDS-Net trial demonstrated a significant reduction in mortality in ALI/ARDS patients who received mechanical ventilation with a VT of 6 mL/kg predicted body weight (PBW) compared to those who received a VT of 12 mL/kg (39.8 vs. 31% respectively). SFGH has adapted the ARDS-Net low VT protocol for routine clinical management of ALI/ARDS patients. We inquired if this change in clinical practice resulted in a lower mortality.
Methods: We reviewed the data on 180 ALI/ARDS patients managed with the ARDS-Net protocol from September 2000 to June 2003. Patients were placed on the protocol within 1.2 ± 2.7 days of meeting consensus conference criteria for ALI/ARDS (7.7% ALI and 92.3% ARDS). Day 1 protocol data was compared to Day 1 control data from 93 ARDS patients (January 1998 to January 1999) managed by routine practice. Data were analyzed using 2-sided unpaired t-tests; mortality was compared by 2-sided Fisher Exact test. Alpha was set at 0.05.
Results: Use of the ARDS-Net protocol was associated with a 40% relative-reduction in hospital mortality at our institution and an overall mortality rate similar to the ARDS-Net study.
| ARDS Net Protocol | Controls | p | |
| Lung Injury Score | 2.82 ± 0.49 | 2.70 ± 0.52 | 0.06 |
| SAPS | 41.7 ± 14.3 | 44.1 ± 15.9 | 0.22 |
| Age | 44.8 ± 15.0 | 44.7 ± 14.2 | 0.96 |
| Pplat (cm H2O) | 27.6 ± 8.5 | 33.8 ± 8.9 | <0.0001 |
| PEEP (cm H2O) | 9.8 ± 3.1 | 7.4 ± 3.3 | <0.0001 |
| Pplat-PEEP (cm H2O) | 17.8 ± 5.5 | 26.4 ± 8.4 | <0.0001 |
| VT (mL/kg PBW) | 6.16 ± 0.98 | 9.75 ± 1.54 | <0.0001 |
| Mortality | 32% | 53% | 0.0016 |
CONCLUSION: Because age, lung injury and illness-severity scores were the same, the observed mortality reduction may be attributable to the marked reductions in VT, Pplat, Pplat-PEEP pressure-excursions and higher PEEP levels. At our institution, clinical adaptation of the ARDS-Net low VT protocol significantly reduced morality compared to recent routine clinical practice at approximately 10 mL/Kg PBW.