Transoral Nasal Cannula Oxygen Therapy for Mouth-Breathing Patients in the Postanesthesia Care Unit

NCT07841223 | Not Yet Recruiting DMC

• 1 other identifier: KY20260723-02
• Study Type: interventional
• Target: 64
• Locations: 1 country
• Sites: 1

Brief Summary

Postoperative hypoxemia is a common complication in the postanesthesia care unit (PACU). Patients who breathe through the mouth after tracheal extubation may receive limited benefit from standard nasal cannula oxygen therapy, because the nasal cavity functions as an ineffective dead space during mouth breathing. Clinical observations suggest that placing the prongs of a nasal cannula inside the mouth (transoral oxygen delivery) rapidly improves oxygenation in these patients. However, no randomized controlled trial has formally verified this effect. This single-center, randomized, controlled, crossover trial will enroll 64 adult patients identified as persistent mouth breathers after extubation in the PACU following elective thoracic or abdominal surgery under general anesthesia. Each participant will receive, in a randomized sequence, both standard nasal cannula oxygen delivery (4 L/min for 10 minutes) and transoral nasal cannula oxygen delivery (4 L/min for 10 minutes), separated by a 5-minute washout period, so that each participant serves as his or her own control. The primary outcome is the incidence of hypoxemia (peripheral oxygen saturation \[SpO2\] \<90% sustained for at least 10 seconds, or oxygenation index \[PaO2/FiO2 ratio\] \<300 mmHg) during each oxygen delivery period. Secondary outcomes include the incidence of SpO2 \<92%, time to achieve SpO2 \>=95%, oxygenation index measured by arterial blood gas analysis, need for escalation of oxygen therapy, vital signs, patient comfort and adverse effects, PACU length of stay, and respiratory complications within 24 hours after surgery. The results are expected to provide high-level evidence for optimizing oxygen therapy strategies for mouth-breathing patients in the PACU.

Conditions

Postoperative Hypoxemia

Keywords

Nasal cannula; Transoral oxygen delivery; Postanesthesia care unit (PACU); Oxygen therapy; Crossover trial; Pulse oximetry (SpO2); Oxygenation index

Outcome Measures

Primary Outcomes (1)

• Incidence of hypoxemia during the oxygen delivery periods

  Hypoxemia is defined as peripheral oxygen saturation (SpO2) \<90% sustained for at least 10 seconds, or an oxygenation index (PaO2/FiO2 ratio) \<300 mmHg measured by arterial blood gas analysis at minute 10 of the intervention period. The outcome is reported as the proportion of participants experiencing hypoxemia during the nasal oxygen delivery period compared with the transoral oxygen delivery period.

  During each 10-minute oxygen delivery period in the PACU (each participant undergoes two consecutive intervention periods)

Secondary Outcomes (14)

• Incidence of SpO2 <92%

  During each 10-minute oxygen delivery period in the PACU

• Oxygenation index (PaO2/FiO2 ratio)

  At minute 10 of each 10-minute oxygen delivery period

• Time to achieve SpO2 >=95%

  From the start of each oxygen delivery period, up to 10 minutes

• Proportion of participants requiring escalation of oxygen therapy

  Throughout the PACU stay (up to 24 hours after surgery)

• Respiratory rate

  Preoperatively; at the start of surgery; at the end of surgery; after extubation; 1 minute before and 1 minute after each change of oxygen delivery route; at PACU discharge

Study Arms (2)

Sequence ON: Transoral oxygen first, then nasal oxygen

ACTIVE COMPARATOR

Participants receive transoral nasal cannula oxygen delivery (4 L/min for 10 minutes), followed by a 5-minute washout period (nasal oxygen delivery resumed), and then standard nasal cannula oxygen delivery (4 L/min for 10 minutes).

Other: Transoral nasal cannula oxygen delivery

Sequence NO: Nasal oxygen first, then transoral oxygen

ACTIVE COMPARATOR

Participants receive standard nasal cannula oxygen delivery (4 L/min for 10 minutes), followed by a 5-minute washout period (nasal oxygen delivery resumed), and then transoral nasal cannula oxygen delivery (4 L/min for 10 minutes).

Other: Transoral nasal cannula oxygen delivery

Interventions

Transoral nasal cannula oxygen delivery OTHER

The two prongs of a standard dual-prong nasal cannula are joined and placed in the oral vestibule at the inner aspect of the mouth corner (approximately at the buccal mucosa corresponding to the first molar), to a depth of no more than 3 cm to avoid stimulating the gag reflex. Oxygen flow is set at 4 L/min with standard humidification for 10 minutes.

Sequence NO: Nasal oxygen first, then transoral oxygen; Sequence ON: Transoral oxygen first, then nasal oxygen

Eligibility Criteria

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

You may qualify if:

• Aged older than 18 years;
• American Society of Anesthesiologists (ASA) physical status classification I-III;
• Undergoing elective thoracic or abdominal surgery under general anesthesia with postoperative transfer to the postanesthesia care unit (PACU);
• Anticipated PACU stay of at least 30 minutes to allow an adequate observation window for data collection;
• Recovery of spontaneous breathing after tracheal extubation, and confirmed as persistent mouth breathing by the standardized three-step assessment procedure (visual screening, cotton-fiber airflow verification, and mirror confirmation);
• Written informed consent signed by the patient or a family member.

You may not qualify if:

• Preoperative diagnosis of severe obstructive sleep apnea-hypopnea syndrome (apnea-hypopnea index \[AHI\] \>30) or requirement for continuous positive airway pressure therapy;
• Severe hypoxemia requiring immediate escalation of oxygen therapy (SpO2 \<90% or PaO2 \<60 mmHg);
• Requirement for reintubation or placement of an oropharyngeal or nasopharyngeal airway after surgery;
• Hemodynamic instability requiring vasoactive agents to maintain mean arterial pressure (MAP \<65 mmHg).

Sponsors & Collaborators

• Nanjing First Hospital, Nanjing Medical University: lead

Study Sites (1)

Nanjing First Hospital, Nanjing Medical University

Nanjing, Jaingsu, 210006, China

Location

Study Officials

• Shuai Wang

  Nanjing First Hospital, Nanjing Medical University

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Shuai Wang

CONTACT

+8618852095101; wangshuaisj@126.com

YING ZHANG

CONTACT

025-52271064

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: OUTCOMES ASSESSOR
• Masking Details: Blinding of participants and care providers is not feasible because the position of the nasal cannula (nasal versus transoral) is visually identifiable during the intervention.
• Purpose: TREATMENT
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Deputy Chief Nurse

Study Record Dates

• First Submitted: September 15, 2026
• First Posted: September 25, 2026
• Study Start (Estimated): November 1, 2026
• Primary Completion (Estimated): December 1, 2027
• Study Completion (Estimated): December 31, 2027
• Last Updated: September 25, 2026

Record last verified: 2026-09

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, ICF, CSR
• Time Frame: ALWAYS
• Access Criteria: All data relevant to the study can be shared for only non-commercial purpose

Locations

CN (1)