FACTORS AFFECTING SUCCESS RATE OF FIRST PASS RAPID SEQUENCE INTUBATION IN CORRELATION WITH MODIFIED LEMON SCORE

Abstract

Objective: More accurate assessment of the success rate of first-pass endotracheal intubation (ETI) with rapid sequence intubation (RSI) and related factors (such as the modified (m) LEMON score) in critically ill patients presenting in the emergency department (ED).

Study Design: Cross-sectional study.

Place and Duration of Study: Department of Emergency Medicine, Indus Hospital and Health Network (IHHN), Location: Karachi, Duration of study: From January 2025 to June 2025.

Methodology: 94 critically ill patients 14-75 years of age, who required emergent intubation as part of the emergency department care were sampled by non-probability consecutive sampling. Details for Operator level, type of laryngoscope used and the indication for intubation were recorded before intubation. First-PRSI success was defined as tube correctly placed in the airway with no change in tube placement required after the initial attempt (bilateral equal air entry). The data was analyzed using SPSS version 24.0, binary logistic regression was used to determine the factors independently associated with first-pass success.

Results: 94 patients were included. 72 patients (76.6%) had a first-pass RSI success. A modified LEMON score <1 was highly associated with first-pass success (80.6% vs 27.3% in failure, p<0.001). The success was higher in the senior operators (EM physicians/ consultants) as compared to the residents/ medical officers (70.8% vs. 29.2% p = 0.009). Multivariate analysis revealed that favorable LEMON score (adjusted OR 6.84, 95% CI 2.41 to 19.42), video laryngoscopy (adjusted OR 2.91, 95% CI 1.02 to 8.31) and senior operator level (adjusted OR 3.35, 95% CI 1.18–9.51) were each independent predictors of success.

Conclusion: The chance of first-pass RSI success in this cohort was 76.6% and was independently associated with a modified LEMON score, video laryngoscopy and increased operator experience. All emergency airway assessments should routinely include pre-intubation LEMON scoring to help predict and prepare for challenging scenarios.