A Comparative Study Between Nebulized Unfractionated Heparin Versus Nebulized N-Acetylcysteine in Acute Lung Injury After Smoke Inhalation Injury

Abstract

Smoke inhalation injury is a major contributor to morbidity and mortality in severely burned patient, in which risk for development of fatal respiratory failure is greater than 50%, the co-presence of bronchopulmonary injury with cutaneous burn covering at least 30% of total body surface area increases mortality rate to more than 70%. Inhalational injury may further predispose burned victim to pneumonia which increase the mortality rate by 90% (Thai et al., 2010).. The inflammatory mediators lead to intrapulmonary leukocyte aggregation following activation of the classic complement cascade releases even more chemokines and cytokines, leading to the production of oxygen free radicals. The combination of these effects contributes to tissue injury and increased pulmonary vascular permeability, leading to decreased diffusion, oedema and V/Q mismatch. Furthermore, neutrophil infiltration and fibrinogen activation by inflammatory mediators causes airway cast formation and widespread plugging (Michael et al., 2010). Nebulization of heparin was found to attenuate pulmonary coagulopathy but didn’t affect fibrinolysis. It also reduced pulmonary inflammation and endothelial permeability. In addition, reduced bacterial outgrowth and bacterial adherence to lung epithelium (Hofstra et al., 2010). A regimen of aerosolized solution of 20 %N-acetylcysteine was studied on adult populations with inhalation injury diagnosed by bronchoscope which act as a mucolytic agent, and diminish airway cast formation. Our study was conducted on 60 burned patients who were matching the inclusion criteria assigned randomly to 2 groups each containing 30 patients. Group H :30 patients: was treated with 10,000 units of nebulized heparin sulfate mixed in 3ml of normal saline every 4 hours. Group A :30 patients: was treated with 3 ml of 20% nebulized N Acetylcysteine every 4 hours. The result of the study showed that the use of nebulized unfractionated heparin had a superior effect in treatment of inhalational acute lung injury rather than N-acetyl cysteine specially in downgrading the grade of inhalational injury in heparin group which confirmed by fibro optic bronchoscopic finding. Not only that but also nebulization of unfractionated heparin improves lung injury score and shorten the staying on mechanical ventilation rather than N-acetyl cysteine which in role decrease the ICU stay and improve outcome and decreasing the mortality. Using unfractionated heparin nebulization by dose of 10,000 units of nebulized heparin sulfate mixed in 3ml of normal saline every 4 hours was very safe and had no effect on aPTT and Platelet count at all.

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