Reliability of assessment of nasal flow rate for nostril selection during nasotracheal intubation

Study Objective: To evaluate the reliability of assessments of nasal flow rate for improved nostril selection for nasotracheal intubation. Design: Prospective, randomized, double-blinded study. Setting: Operating room of a university-affiliated hospital. Patients: 118 ASA physical status 1 and 2 patients, aged 18-65 years, scheduled for elective maxillofacial and oral surgery requiring nasotracheal intubation. Interventions: Patients were randomized to the left or right nostril groups. Forced vital capacity (FVC) and forced expiratory volume in one second (FEV₁) through the mouth and each nostril were measured before anesthesia induction. Measurements: The relationship between the rate of airflow through the selected nostril and frequency of epistaxis and navigability of the nasotracheal tube were evaluated. Main Results: There were no significant differences in the frequency of epistaxis and degree of navigability of the tracheal tube between the left and right nostril groups. In both nostril groups, patients who suffered epistaxis showed significantly less FEV₁ and FEV₁/FVC values than did patients without epistaxis (P < 0.05). In addition, in both groups patients who passed the tube easily showed significantly higher FEV₁ and FEV₁/FVC values than did patients who passed the tube with resistance or failed tube passage (P < 0.05). Conclusion: Measurement of nasal flow rate is a useful clinical method for choosing a nostril for nasotracheal intubation.