Increased Ratio of Dead Space to Tidal Volume in Subjects With Inhalation Injury.

BACKGROUND: Inhalation injury increases morbidity and mortality in burn patients. Patients with inhalation injury present with large differences between end-tidal CO2 pressure and [Formula: see text], 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 ([Formula: see text]/[Formula: see text]) were calculated. Independent t tests were used to compare mean [Formula: see text]/[Formula: see text] of survivors to that of subjects who died and between subjects with and without pneumonia. The relationships between [Formula: see text]/[Formula: see text] 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 [Formula: see text]/[Formula: see text] was 0.38. Ten subjects died, and 6 subjects had pneumonia. The [Formula: see text]/[Formula: see text] 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). [Formula: see text]/[Formula: see text] correlated significantly with modified Baux score (r = .524, P < .001). CONCLUSIONS: Alveolar dead space ([Formula: see text]/[Formula: see text]) is easily calculated from [Formula: see text] 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.

Time Matters in Severe Frostbite: Assessment of Limb/Digit Salvage on the Individual Patient Level.

Severe frostbite is associated with high levels of morbidity through loss of digits or limbs. The aim of this study was to examine the salvage rate following severe frostbite injury. Frostbite patients from 2006 to 2014 were identified in the prospectively maintained database at a single urban burn and trauma center. Patients with imaging demonstrating a lack of blood flow in limbs/digits were included in the analysis (N = 73). The Hennepin Frostbite Score was used to quantify frostbite injury and salvage. This score provides a single value to assess each individual patient's salvage rate. The majority of patients with perfusion deficits were male (80%) with an average age of 42 years (range 11-83 years). Patients requiring amputation tended to be older (P = .002), have more tissue impacted by frostbite (P < .001), and experienced a longer time from rewarming to thrombolytic therapy (P = .001). A majority of patients (62%) received thrombolytic treatment. The percentage of patients requiring amputation was lower and the salvage rate was higher in patients treated with thrombolytics; however, the differences failed to reach statistical significance (P = .092 and P = .061, respectively). The rate of salvage decreases as the time from rewarming to thrombolytic therapy increases. Regression analysis demonstrates an additional 26.8% salvage loss with each hour of delayed treatment (P = .006). When the amount of tissue at risk for amputation is included in the model, each hour delay in thrombolytic treatment results in a 28.1% decrease in salvage (P = .011). This study demonstrates a significant decrease in limb/digit salvage with each hour of delayed administration of thrombolytics in patients with severe frostbite.