Background: Atelectasis is common in patients undergoing prolonged deep sedation outside the operating theatre. High-flow nasal oxygen (HFNO) produces positive airway pressure which, hypothetically, should improve lung atelectasis, but this has not been investigated.
Objective: We investigated whether HFNO ameliorates postprocedural atelectasis and compared the influences of HFNO and facial oxygen by mask on postprocedural outcomes.
Design: A single-blind, open-label single-institution randomised controlled trial.
Setting: A single university hospital, from February 2017 to July 2019.
Patients: A total of 59 patients undergoing computed tomography (CT)-guided hepatic tumour radiofrequency ablation were randomly allocated to two groups.
Intervention: These patients randomly received HFNO (oxygen flow 10 l min before sedation and 50 l min during the procedure) or a conventional oxygen face mask (oxygen flow 10 l min) during the procedure.
Main outcome measures: Changes in the area of lung atelectasis calculated on the basis of chest CT images and also recovery profiles were compared between the two groups.
Results: The two groups had comparable procedural profiles, but the HFNO group exhibited less postprocedural atelectasis than the face mask group (median [IQR] 7.4 [3.9 to 11.4%] vs. 10.5 [7.2 to 14.6%]; P = 0.0313). However, the numbers of patients requiring oxygen supplementation in the recovery room and during transport from the recovery room to the ward did not differ significantly between groups (24.1 vs. 50.0%; P = 0.0596).
Conclusion: Our results suggested that HFNO ameliorates lung atelectasis after prolonged deep sedation in patients receiving CT-guided hepatic tumour radiofrequency ablation.
Trial registration: Clinicaltrials.gov Identifier: NCT03019354.