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ARDSNet

"Ventilation with Lower Tidal Volumes as Compared with Traditional Tidal Volumes for Acute Lung Injury and the Acute Respiratory Distress Syndrome". The New England Journal of Medicine. 2000. 342(18):1301-1308. PubMed • Full text • PDF

1. Clinical Question
2. Bottom Line
3. Major Points
4. Guidelines
5. Design
6. Population
6.1 Inclusion Criteria
6.2 Exclusion Criteria
6.3 Baseline Characteristics
7. Interventions
8. Outcomes
8.1 Primary Outcomes
8.2 Secondary Outcomes
9. Funding
10. Further Reading

Clinical Question

Among patients with acute lung injury (ALI) and the acute respiratory distress syndrome (ARDS), does mechanical ventilation with lower tidal volumes improve mortality compared to traditional tidal volumes?

Bottom Line

In patients with ALI and ARDS, mechanical ventilation with lower tidal volumes (6 ml/kg of predicted body weight) compared to traditional tidal volumes (12 ml/kg of predicted body weight) resulted in decreased mortality and increased the number of days without ventilator use.

Major Points

Mechanical ventilation with tidal volumes of 10 to 15 ml/kg is traditional but may worsen lung injury in patients with ALI and ARDS. This randomized trial tested whether ventilation with lower tidal volumes would improve outcomes in these patients, finding that lower tidal volumes resulted in a 22% relative reduction in mortality and more ventilator-free days when compared with traditional volumes.

Guidelines

Current guidelines recommend the use of lower tidal volume ventilation in patients with ALI and ARDS to prevent ventilator-induced lung injury.

Design

Multicenter, randomized trial comparing traditional ventilation with lower tidal volume ventilation in ALI/ARDS patients. Enrolled 861 patients, mean follow-up of 180 days.

Population

Patients with ALI or ARDS who were intubated and mechanically ventilated, age ≥18 years.

Inclusion Criteria

- Acute onset hypoxemia with a PaO2/FiO2 ratio ≤300
- Bilateral pulmonary infiltrates consistent with edema on chest radiograph
- No clinical signs of elevated left atrial hypertension or pulmonary capillary wedge pressure ≤18 mm Hg if measured

Exclusion Criteria

- Ventilated >36 hours prior to eligibility, pregnancy, increased intracranial pressure, neuromuscular disease, severe chronic respiratory disease, severe burn injurie, contraindications to full life support, etc.

Baseline Characteristics

- Groups were well balanced
- Minute ventilation was slightly higher in the lower volume group (P=0.01)

Interventions

Two groups were created:
- Traditional volumes starting at 12 ml/kg of predicted body weight with plateau pressure ≤50 cm of water
- Lower volumes starting at 6 ml/kg of predicted body weight with plateau pressure ≤30 cm of water

Outcomes

Primary Outcomes
- Mortality rate was lower in the lower tidal volume group (31% vs. 39.8%; P=0.007)
- More days without ventilator use in lower volume group (12±11 vs. 10±11; P=0.007)

Secondary Outcomes
- The number of days without nonpulmonary organ failure was higher in the lower tidal volume group

Criticisms

- Mild-to-moderate respiratory acidosis may have occurred due to the lower tidal volumes

Funding

Supported by contracts with the National Heart, Lung, and Blood Institute.