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

Condition(s) studied

Investigational drug(s) / intervention(s)

Transoral nasal cannula oxygen delivery: 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.

Study 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.

Eligibility

Primary outcome measure(s)

• Incidence of hypoxemia during the oxygen delivery periods — During each 10-minute oxygen delivery period in the PACU (each participant undergoes two consecutive intervention 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.

Trial sites (1)

More Nanjing First Hospital, Nanjing Medical University trials in China

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