Impact of nebulized unfractionated heparin and N-acetylcysteine in management of smoke inhalation injury

Introduction

Approximately 70% of all fire victims in the USA who die within the first 12 hours post burn die from smoke inhalation injury (SIJ). Airway edema combined with obstructive casts produced from cellular debris, fibrin clots, polymorphonuclear leukocytes, mucus and mucin B5 are believed to cause the airway obstruction contributing to pulmonary failure.

Methods

A single-center retrospective study with historical control over a 5-year period of 30 mechanically ventilated adult subjects admitted within 48 hours of their bronchoscopy with confirmed SIJ. Both the experimental (n = 16) group and control (n = 14) groups were treated with ventilator support but the former received in addition 10,000 units of nebulized heparin sulfate mixed in 3 ml normal saline every 4 hours and 3 ml 20% nebulized N-acetylcysteine plus 0.5 ml albuterol sulfate every 4 hours for 7 consecutive days starting on the day of admission. We calculated APACHE III scores on admission in addition to the daily lung injury score for 7 days.

Results

There was no significant difference in admission APACHE III scores (38.7 vs. 34.6; α = 0.05) or lung injury scores (0.7 vs. 1.1; α = 0.05) between the experimental and control groups. The experimental group showed significant improvement in lung injury scores (P < 0.05) over the duration of the study, with the greatest benefit seen over the first 7 days (0.91 ± 0.14 vs. 1.79 ± 0.41; P < 0.01). Respiratory resistance and compliance measurements revealed significant improvement in the experimental group reaching a significance level of P < 0.01 by day 4. There was a statistically significant survival benefit in the experimental group that was most pronounced in patients with APACHE III scores >35. Survival for the control group versus experimental group was 0.5714 ± 0.1497 versus 0.9375 ± 0.0605, respectively (RR = -0.0055; 95% CI = -0.0314 to 0.0204; HR = 1.003).

Conclusion

The use of aerosolized unfractionated heparin and N-acetylcysteine attenuates lung injury and the progression of acute lung injury in ventilated adult patients with SIJ.