Effect of cricoid pressure on laryngeal view during prehospital tracheal intubation: a propensity-based analysis.

BACKGROUND The benefit of cricoid pressure during tracheal intubation is still debated and, due to its potential negative impact on laryngeal views, its routine use is questioned. The goal of this study was to estimate its impact on laryngeal view. METHODS All patients intubated in the prehospital setting were included. Three different propensity score (PS) models were used and compared in terms of the balance achieved between those patients who received cricoid pressure and those who did not. The PS model that optimised the balance was retained in order to estimate the relationship between cricoid pressure and the following outcomes: difficult laryngoscopy, intubation-related complications and difficult intubation. RESULTS Among the 1195 patients included, 499 (41.7%) received cricoid pressure. The optimal PS included seven variables (cardiac arrest, altered neurological status, shock, respiratory distress, gender, obesity, patient's position). After PS matching, no significant risk difference (RD) in the rate of difficult laryngoscopy was found between the patients who received cricoid pressure and those who did not (RD=0.001, 95% CI -0.07 to 0.08, p=0.50). No significant difference was found in terms of difficult intubation (RD=0.06, 95% CI -0.13 to 0.25, p=0.28) and in terms of prevalence of complications, except for airway trauma that were more frequent in cricoid pressure group (RD=0.03, 95% CI 0.002 to 0.05, p=0.01). CONCLUSIONS No significant relationship was found between the use of cricoid pressure for prehospital intubation and difficult laryngoscopy. Cricoid pressure was found to be associated with more airway trauma. This finding could question its routine use.