Implementation of High-Flow Oxygen Therapy in a Surgical High-Dependency Unit: A Cohort Study

Abstract

Background: High-flow oxygen therapy (HFOT) is a non-invasive respiratory support method traditionally used in the intensive care unit (ICU) settings for patients with acute hypoxemic respiratory failure. It delivers a consistent flow of humidified oxygen at high flow rates, improving oxygenation and reducing the work of breathing. The advantages of HFOT, such as its ability to provide a high fraction of inspired oxygen (FiO2) and its ease of use, have prompted its use beyond the ICU walls in various medical settings. This study examines the feasibility and safety of implementing HFOT in a surgical high-dependency unit (SHDU) at Singapore General Hospital (SGH), where it was introduced as part of a protocol to optimize patient care and ICU resource utilization.

Objective: The primary aim of this study was to evaluate the implementation of HFOT outside the ICU in SHDUs, assessing patient outcomes and the effectiveness of a structured training protocol for healthcare providers.

Methods: This cohort study was conducted in the SHDUs of SGH, a tertiary healthcare institution. The study population consisted of 89 patients who received HFOT across 96 administrations. A standardized HFOT protocol was developed to guide patient selection, initiation, monitoring, and management, with close supervision by the Rapid Response Team (RRT). A comprehensive staff training program was implemented, which included face-to-face training, online in-service education, and ongoing support for nurses. HFOT was delivered using the AIRVO™ 2 machine, which can provide up to 60 liters per minute of flow and an FiO2 of up to 0.95.

Results: A total of 96 HFOT administrations were analyzed, with the mean patient age being 70.8 years and 65% of patients being male. The average duration of HFOT was 40.2 hours. Of the 81 patients analyzed, 64 (66.7%) were successfully weaned to conventional oxygen therapy, while 24 (25%) required ICU-level ventilatory support. The implementation process involved a pilot phase in two SHDUs, followed by full-scale deployment across all units. However, the COVID-19 pandemic disrupted the process, leading to a temporary suspension of HFOT use in non-isolation wards for several months. Despite this setback, when restrictions were lifted, HFOT use outside the ICU expanded significantly, with a notable increase in the number of HFOT initiations in non-pilot wards. The implementation of HFOT outside the ICU faced challenges such as limited hands-on experience and logistical issues, which were addressed through structured training, additional equipment, and a mobile application for setup. Despite these efforts, delays and the lack of machine portability remained barriers to optimal implementation.

Conclusion: The successful implementation of HFOT in SHDUs at SGH highlights its feasibility as an effective alternative to ICU care for selected patients. More than two-thirds of patients who received HFOT were successfully managed without requiring escalation to ICU-level care. This study underscores the importance of structured protocols, staff education, and appropriate resource allocation in ensuring the safe and effective use of HFOT outside of the ICU.

Keywords: high-flow oxygen therapy; icu resource optimization; implementation; respiratory support; staff training; surgical high dependency unit.

Figure 1. High-flow oxygen therapy protocol for surgical high-dependency units

HFOT: high-flow oxygen therapy; HR: heart rate; NIV: non-invasive ventilation; PaCO2: partial pressure of carbon dioxide in arterial blood; RR: respiratory rate; RRT: rapid response team; SBP: systolic blood pressure; SICU: surgical intensive care unit

Figure 2. Numbers of high-flow nasal cannula initiations per quarter in SHDUs

HFOT: high-flow oxygen therapy; SHDUs: surgical high-dependency units; blue: initiations in the pilot SHDUs; orange: initiations in non-pilot SHDUs; bracket: period of COVID-19 restrictions limiting the use of HFOT in SHDUs