Related Experiment Video
Updated: Apr 15, 2026

Surfactant Depletion Combined with Injurious Ventilation Results in a Reproducible Model of the Acute Respiratory Distress Syndrome ARDS
Published on: April 7, 2021
The Adult Calfactant in Acute Respiratory Distress Syndrome Trial
Douglas F Willson1, Jonathon D Truwit2, Mark R Conaway3
1Department of Pediatrics, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA.
Insights
Calfactant, a calf lung surfactant, did not improve survival or oxygenation in adults with acute respiratory distress syndrome (ARDS). This study suggests exogenous surfactant is not currently recommended for ARDS treatment.
Area of Science:
- Pulmonology
- Critical Care Medicine
- Pharmacology
Background:
- Surfactant dysfunction is implicated in acute respiratory distress syndrome (ARDS).
- Exogenous surfactant has shown efficacy in pediatric acute lung injury (ALI).
- Calfactant, a calf lung surfactant, was investigated for adult and pediatric ALI/ARDS.
Purpose of the Study:
- To evaluate the efficacy and safety of calfactant in adult patients with direct lung injury-induced ARDS.
- To determine if calfactant improves 90-day all-cause mortality, length of stay, or oxygenation.
Main Methods:
- Multi-institutional, randomized, controlled, and masked trial.
- Adult subjects with direct ARDS initiated on mechanical ventilation were randomized.
- Interventions included instilled calfactant versus air placebo, with up to three treatments.
Main Results:
- 317 subjects enrolled; 308 evaluated, with no significant baseline differences.
- Calfactant administration showed no improvement in survival, length of stay, or oxygenation.
- Transient hypoxia and hypotension were frequent adverse events; the study was stopped early.
Conclusions:
- Calfactant administration did not demonstrate improved oxygenation or long-term benefits compared to placebo.
- Exogenous surfactant is not recommended for routine clinical use in ARDS at this time.
- Further research into surfactant therapy for ARDS may be warranted, potentially with different formulations.
Background:
Surfactant has been shown to be dysfunctional in ARDS, and exogenous surfactant has proven effective in many forms of neonatal and pediatric acute lung injury (ALI). In view of the positive results of our studies in children along with evidence that surfactant-associated protein B containing pharmaceutical surfactants might be more effective, we designed a multiinstitutional, randomized, controlled, and masked trial of calfactant, a calf lung surfactant, in adults and children with ALI/ARDS due to direct lung injury.
Methods:
Adult subjects within 48 h of initiation of mechanical ventilation for direct ARDS were randomized to receive up to three interventions with instilled calfactant vs air placebo. The primary outcome was 90-day all-cause mortality.
Results:
Three hundred seventeen subjects were enrolled, 308 of whom could be evaluated. There were no significant baseline differences between groups. Calfactant administration was not associated with improved survival, lengths of stay, or oxygenation. Calfactant instillation was frequently associated with transient hypoxia and hypotension. The study was stopped at the first interim analysis at the sponsor's request.
Conclusions:
Administration of calfactant was not associated with improved oxygenation or longer-term benefits relative to placebo in this randomized, controlled, and masked trial. At present, exogenous surfactant cannot be recommended for routine clinical use in ARDS.
Trial Registry:
ClinicalTrials.gov; No.: NCT00682500; URL: www.clinicaltrials.gov.
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07:20Lavage-induced Surfactant Depletion in Pigs As a Model of the Acute Respiratory Distress Syndrome ARDS
Published on: September 7, 2016
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