The use of transnasal humidified rapid insufflation ventilatory exchange in laryngeal and pharyngeal surgery: Flinders case series

Background: Transnasal humidified rapid insufflation ventilatory exchange (THRIVE) is a new anaesthetic technique that allows for prolonged apnoeic oxygenation without intubation. THRIVE is often conducted in patients with a normal body mass index (BMI) and mild systemic disease. However, it is unclear if patients with an increased BMI or significant co-morbidities are able to safely undergo laryngeal and pharyngeal surgery with THRIVE. Methods: A 14-month retrospective case note review was conducted in patients who underwent THRIVE for ear, nose, and throat (ENT) upper airway surgery. Factors were analysed to identify relationships with the requirement for rescue ventilation: age, BMI, American Society of Anaesthesiologists (ASA) physical status, smoking status, medical history and procedure type. An analysis was performed using non-parametric tests and odds ratios. Results: THRIVE was used with the following upper airway procedures (n=56): microlaryngoscopy with injection laryngoplasty (n=7), microlaryngoscopy with biopsy (n=14), microlaryngoscopy with potassium titanyl phosphate (KTP) laser use (n=11), panendoscopy with biopsy (n=10), oesophageal dilatation (n=3), subglottic stenosis dilatation (n=10), and stapling of a pharyngeal pouch (n=1). Rescue bag and mask ventilation or intubation were required in 21% of cases (n=12). A weight of more than 80 kg or BMI more than 30 were 5.2 and 5.7 times respectively more likely to require rescue ventilation (Fisher Exact Test P=0.023 and P=0.021). Conclusions: THRIVE can be safely used for a variety of laryngeal and pharyngeal procedures. However, there is a higher likelihood of rescue ventilation if the patient is over 80 kg or has a BMI over 30. Prospective investigation with a larger dataset of patients is required to validate these results.