Abstract
BACKGROUND: Inhalation injury increases morbidity and mortality in burn patients. Patients with inhalation injury present with large differences between end-tidal CO2 pressure and , an indirect measure of dead space. We aimed to investigate the relationships between increased dead space and inhalation injury outcomes.
METHODS: This retrospective study included 51 adult subjects with burns and inhalation injuries. Demographics, size of burns, length of stay, ventilator days, blood gas results, end-tidal CO2 pressure, presence of ventilator-associated pneumonia, and mortality data were collected. Modified Baux scores and ratios of alveolar dead space to alveolar tidal volume (/) were calculated. Independent t tests were used to compare mean / of survivors to that of subjects who died and between subjects with and without pneumonia. The relationships between / and ventilator days or modified Baux score were assessed with bivariate correlation analysis.
RESULTS: Our population had a mean age of 52 y and an average burn size of 17.5%. The average length of stay and ventilator days were 12 d and 3.8 d, respectively. The mean modified Baux score was 87. The mean / was 0.38. Ten subjects died, and 6 subjects had pneumonia. The / of survivors was significantly smaller for survivors than for subjects who died (0.34 vs 0.52, P = .03). No significant difference was observed between subjects with and without pneumonia (0.36 vs 0.47, P = .26). / correlated significantly with modified Baux score (r = .524, P < .001).
CONCLUSIONS: Alveolar dead space (/) is easily calculated from and end-tidal CO2 pressure and may be useful in assessing severity of inhalation injury, the patient’s prognosis, and the patient’s response to treatment.
- burn
- inhalation injury
- mortality
- ratio of dead space to tidal volume
- dead space fraction
- modified Baux scores
- total burn surface area
Footnotes
- Correspondence: Thomas Granchi MD MBA, Department of Surgery, Acute Care Surgery Division, University of Iowa Hospitals and Clinics, 200 Hawkins Dr, Iowa City, IA 52242. E-mail: tgranch{at}emory.edu
At the time of this study, all authors were affiliated with the Department of Surgery, Acute Care Surgery Division, University of Iowa Hospitals & Clinic Iowa City, Iowa.
The authors have disclosed no conflicts of interest.
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