Purpose: To assess the effect of systemic corticosteroids on endotracheal tube (ETT) related laryngotracheal trauma.
Methods: A Single blinded, randomized controlled animal study in a previously validated porcine model of hypoxia induced accelerated airway injury. Fourteen Sus Scrofa piglets (15.5-17.8 kg) were intubated using a 6.5 cuffed endotracheal tube and maintained on constant hypoxic ventilation, with oxygen saturation under 70%, for a period of 4 hrs. Endotracheal tube cuff pressure was monitored and maintained throughout the procedure. The pigs were randomized into 2 groups: 7 pigs were premedicated with 0.4mg/kg of i.v. dexamethasone, 30 minutes prior to the start of the hypoxia while 7 pigs served as controls. The primary outcome measure was histopathological grading of the laryngotracheal injury by a pathologist. (Figure 1)
Results: All the pigs successfully completed the experiment protocol. There was a statistically significant reduction in the cumulative injury score in the steroid group as compared to the controls in the subglottis. (Mean injury score per pig 10.42 vs 16, p=0.0030, Mann-Whitney Test). The mean injury score per section of the subglottis was also less in the steroid group as compared to the controls. (1.469 vs 2.669, p=0.0026). There were a significantly higher number of grade 3 and 4 injuries in the subglottis in the control group as compared to the steroid group. (30 vs 12 , p<0.001). There was no statistically significant difference in the overall mean injury score in the supraglottis, glottis and trachea in both the groups. (Figure 2)
Conclusion: Intravenous steroids help in reducing ETT cuff related subglottic trauma. There was a reduction in more severe grades of airway injury (Grade 3 and 4), which signify acute inflammatory changes in the subepithelium and the perichondrium, with the use of steroids. The study provides evidence that steroids are helpful in preventing airway trauma secondary to endotracheal intubation and thus might have an effective role in reduction of the airway trauma in the setting of prolonged intubation in both the intensive care setting and the operating room.
Figure 2: Comparison between the overall injury score in the steroid group and controls at various subsites