Heated Humidified Oxygen in PACU Patients

NCT07778420 | Not Yet Recruiting DMC

• 3 other identifiers: 2026-23525YXYJZD00025XJTU2AF-2026-235
• Study Type: interventional
• Target: 2,000
• Locations: 1 country
• Sites: 8

Brief Summary

This study aims to determine whether heated and humidified oxygen therapy, compared with conventional room-temperature oxygen therapy, reduces the incidence of early hypoxemia in adult patients recovering from general anesthesia in the Post-Anesthesia Care Unit (PACU). Hypoxemia is a common and potentially life-threatening complication during PACU recovery, resulting from residual anesthetics, decreased upper airway muscle tone, atelectasis, and suppression of hypoxic pulmonary vasoconstriction (HPV). Heated and humidified oxygen may offer benefits by preserving optimal HPV function, protecting airway mucosa, and reducing respiratory resistance. This is a prospective, multicenter, randomized, superiority trial with a parallel-group design. A total of 2,000 adult patients (ASA class I-III) undergoing general anesthesia will be enrolled and randomly assigned in a 1:1 ratio to receive either heated and humidified oxygen (37°C, 5 L/min via face mask) or room-temperature oxygen (room temperature, 5 L/min via face mask). The primary outcome is the incidence of hypoxemia, defined as SpO₂ ≤ 90% lasting ≥ 5 seconds, within 10 minutes after initiation of the intervention. Secondary outcomes include severe hypoxemia (SpO₂ ≤ 85%), requirement for airway interventions, lowest SpO₂ value, PACU length of stay, postoperative shivering, and agitation. Safety outcomes include nasal discomfort, epistaxis, and device-related adverse events.

Conditions

Hypoxemia; Postoperative Complications; Anesthesia Recovery Period

Keywords

Heated and Humidified Oxygen; General Anesthesia; PACU; Randomized Controlled Trial; Oxygen Therapy; Post-Anesthesia Care Unit

Outcome Measures

Primary Outcomes (1)

• Incidence of Hypoxemia Within 10 Minutes

  Hypoxemia is defined as SpO₂ ≤ 90% lasting for ≥ 5 seconds during the 10-minute period immediately after initiation of the study intervention. Only events occurring during normal waveform quality are counted.

  Within 10 minutes after intervention initiation

Secondary Outcomes (8)

• Incidence of Severe Hypoxemia

  Within 10 minutes after intervention initiation

• Lowest SpO₂ Value

  Within 10 minutes after intervention initiation

• Significant SpO₂ Drop >4% From Baseline

  Within 10 minutes after intervention initiation

• Need for Airway Interventions

  During the entire PACU stay

• PACU Length of Stay

  During the entire PACU stay

Study Arms (2)

Heated and Humidified Oxygen Group

EXPERIMENTAL

Patients receive oxygen heated to 36-37°C at 5 L/min via face mask using a dry-heat blood/fluid warmer with a flexible heating sleeve. Temperature is measured every 5 minutes to ensure stability within the target range.

Device: Heated and Humidified Oxygen Therapy

Room-Temperature Oxygen Group

ACTIVE COMPARATOR

Patients receive room-temperature oxygen at 5 L/min via face mask through a bubble humidifier. The same heating device is connected but switched off (sham) to maintain patient blinding. Simulated temperature measurements are recorded as room temperature.

Device: Room-Temperature Oxygen Therapy

Interventions

Heated and Humidified Oxygen Therapy DEVICE

Oxygen heated to 36-37°C using a dry-heat blood/fluid warmer with a flexible heating sleeve, delivered at 5 L/min via face mask. Temperature measured every 5 minutes.

Heated and Humidified Oxygen Group

Room-Temperature Oxygen Therapy DEVICE

Room-temperature oxygen delivered at 5 L/min via face mask through a bubble humidifier. Same heating device but switched off (sham), with simulated temperature measurements recorded as room temperature.

Room-Temperature Oxygen Group

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Age ≥ 18 years
• Undergoing elective or emergency surgery under general anesthesia with endotracheal intubation
• Ramsay Sedation Score of 2-4 at 1 minute after extubation
• ASA physical status class I-III
• Expected PACU stay ≥ 30 minutes
• Patient or legally authorized representative provides written informed consent

You may not qualify if:

• Pre-existing hypoxemia (SpO₂ \< 90% on room air)
• Pre-existing diagnosis of severe chronic obstructive pulmonary disease (GOLD grade 3-4), interstitial lung disease, or uncontrolled asthma
• Severe cardiovascular disease (NYHA class III-IV heart failure, unstable angina)
• Neuromuscular disease affecting respiratory function
• Maxillofacial surgery, severe spinal deformity, or other contraindications to face mask oxygen therapy or positioning
• Use of cardiopulmonary bypass during surgery or planned postoperative ICU admission with endotracheal tube in place
• Known intolerance to heated gas

Sponsors & Collaborators

• Second Affiliated Hospital of Xi'an Jiaotong University: lead

Study Sites (8)

Luoyang Central Hospital

Luoyang, Henan, 471009, China

Location

Xi'an Central Hospital

Xi'an, Shaanxi, 710003, China

Location

The Second Affiliated Hospital of Xi'an Jiaotong University

Xi'an, Shaanxi, 710004, China

Location

Xi'an People's Hospital

Xi'an, Shaanxi, 710004, China

Location

Shaanxi Provincial People's Hospital

Xi'an, Shaanxi, 710068, China

Location

Shaanxi Nuclear Industry 215 Hospital

Xianyang, Shaanxi, 712000, China

Location

Sichuan Cancer Hospital

Chengdu, Sichuan, 610041, China

Location

General Hospital of Western Theater Command, PLA

Chengdu, Sichuan, 610083, China

Location

MeSH Terms

Conditions

Hypoxia; Postoperative Complications

Condition Hierarchy (Ancestors)

Signs and Symptoms, Respiratory; Signs and Symptoms; Pathological Conditions, Signs and Symptoms; Pathologic Processes

Study Officials

• Lei Ma, MD PhD

  Second Affiliated Hospital of Xi'an Jiaotong University

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Lei Ma, MD PhD

CONTACT

13519134023; malei0214@xjtu.edu.cn

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, OUTCOMES ASSESSOR
• Masking Details: The intervention provider operates the device switch and cannot be blinded.
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: August 18, 2026
• First Posted: August 21, 2026
• Study Start (Estimated): September 1, 2026
• Primary Completion (Estimated): December 30, 2027
• Study Completion (Estimated): December 30, 2027
• Last Updated: August 21, 2026

Record last verified: 2026-08

Data Sharing

• IPD Sharing: Will not share

Locations

CN (8)