Optiflow Switch™: a clinical evaluation case series in general anaesthesia for Caesarean delivery

Editor - High-flow humidified nasal oxygen (HFNO) has potential benefits when used for pre-oxygenation and apnoeic oxygenation (known in combination as 'per-oxygenation') 1 Murphy N.E. Coursin D.B. Pryde P. Efficacy vs efficiency using high flow nasal oxygen in peri-intubation oxygenation of gravid women. Int J Obstet Anesth. 2021; 45: 17-20 Abstract Full Text Full Text PDF PubMed Scopus (2) Google Scholar in pregnant people undergoing general anaesthesia. 2 Ellis R. Laviola M. Stolady D. Valentine R.L. Pillai A. Hardman J.G. Comparison of apnoeic oxygen techniques in term pregnant subjects: a computational modelling study. Br J Anaesth. 2022; 129: 581-587 Abstract Full Text Full Text PDF PubMed Scopus (8) Google Scholar , 3 Tan P. Dennis A.T. High flow humidified nasal oxygen in pregnant women. Anaesth Intensive Care. 2018; 46: 36-41 Crossref PubMed Scopus (17) Google Scholar , 4 Zhou S. Zhou Y. Cao X. et al. The efficacy of high flow nasal oxygenation for maintaining maternal oxygenation during rapid sequence induction in pregnancy: a prospective randomised clinical trial. Eur J Anaesthesiol. 2021; 38: 1052-1058 Crossref PubMed Scopus (23) Google Scholar A disadvantage to using current HFNO systems is the need to remove the HFNO nasal cannulae to perform face mask ventilation and assess end-tidal oxygen or carbon dioxide concentrations. 5 Wong C.A. Mushambi M. Peri-intubation oxygenation for Caesarean delivery: is there an optimal technique?. Br J Anaesth. 2022; 129: 468-471 Abstract Full Text Full Text PDF PubMed Scopus (2) Google Scholar A new design modification of the Optiflow system (Fisher & Paykel Healthcare, East Tāmaki, Auckland, New Zealand) called Optiflow Switch™ allows for seamless transition to face mask ventilation without removal of the nasal cannulae. The new Optiflow Switch™ nasal cannulae (Product reference AA041, Fisher & Paykel Healthcare) have one arm that sits flush on the contour of the cheek and the other compressible arm is for gas in-flow (Fig. 1). The modification also includes a flow diverter (Part number AA520, Fisher & Paykel Healthcare) that acts as a pressure relief valve when the compressible arm is occluded by the face mask. 6 Fisher & Paykel Healthcare LimitedOptiflow THRIVE clinician website. F&P Optiflow switch nasal interface. 2023https://www.fphcare.com/au/hospital/optiflow-thrive/home/product-information/optiflow-switch/Date accessed: August 9, 2023 Google Scholar Therefore, when a tight-fitting face mask seal is applied, flow through the HFNO system is completely diverted away from the patient's airway and bag mask ventilation is achievable and safe, and the risk of barotrauma is mitigated. This is pertinent as the Obstetric Anaesthetists' Association (OAA) and Difficult Airway Society (DAS) obstetric airway management guidelines suggest that gentle face mask oxygenation during apnoea is indicated. 7 Mushambi M.C. Kinsella S.M. Popat M. et al. Obstetric Anaesthetists' Association and Difficult Airway Society guidelines for the management of difficult and failed tracheal intubation in obstetrics. Anaesthesia. 2015; 70: 1286-1306 Crossref PubMed Scopus (371) Google Scholar Further to this, Wong and Mushambi 5 Wong C.A. Mushambi M. Peri-intubation oxygenation for Caesarean delivery: is there an optimal technique?. Br J Anaesth. 2022; 129: 468-471 Abstract Full Text Full Text PDF PubMed Scopus (2) Google Scholar in their editorial highlight the utility of low-flow nasal oxygen or HFNO and suggest incorporating either modality during apnoea and laryngoscopy of pregnant people having general anaesthesia.