Transoral Nasal Cannula Oxygen Delivery on Postoperative Hypoxemia for Mouth-breathing Patients After Surgery: a Randomized Controlled Crossover Trial
试验速览
- 阶段
- 不适用
- 状态
- 尚未招募
- 入组人数
- 64
- 试验地点
- 1
- 主要终点
- Incidence of hypoxemia during the oxygen delivery periods
研究概览
简要总结
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.
详细描述
This is a single-center, randomized, controlled, crossover trial conducted in the Department of Anesthesiology, Pain and Perioperative Medicine, Nanjing First Hospital, Nanjing Medical University, China.
Screening and assessment of mouth breathing: Adult patients recovering from general anesthesia for elective thoracic or abdominal surgery are assessed 5 minutes after tracheal extubation using a standardized three-step procedure: (1) visual screening (lip separation >0.5 cm, visible anterior teeth, and lowered mandibular position, observed for 0-10 s); (2) airflow verification using cotton fiber wisps placed approximately 1 cm in front of both nostrils and the lips to identify the dominant ventilation pathway (10-25 s); and (3) mirror confirmation of exhaled vapor condensation together with observation of tongue position (25-40 s). Persistent mouth breathing is confirmed when all three steps are positive and no spontaneous mouth closure lasting more than 3 seconds occurs during the 40-second observation period.
Interventions: (a) Standard nasal cannula oxygen delivery: a standard dual-prong nasal cannula is placed in both nostrils with an oxygen flow of 4 L/min for 10 minutes. (b) Transoral nasal cannula oxygen delivery: the two prongs of the same 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, with an oxygen flow of 4 L/min for 10 minutes. A 5-minute washout period, during which nasal oxygen delivery is resumed, separates the two intervention periods.
Randomization and sequence: Eligible participants are randomly assigned in a 1:1 ratio to one of two sequences. Sequence A (nasal first): nasal oxygen delivery for 10 minutes, 5-minute washout, then transoral oxygen delivery for 10 minutes. Sequence B (transoral first): transoral oxygen delivery for 10 minutes, 5-minute washout, then nasal oxygen delivery for 10 minutes.
Measurements: SpO2 is monitored continuously throughout all periods. Arterial blood gas is sampled at minute 10 of each intervention period through the indwelling radial arterial catheter placed for routine intraoperative monitoring (approximately 1 mL per sample) to calculate the oxygenation index (PaO2/FiO2 ratio). Vital signs, comfort scores, and adverse effects are recorded at predefined time points.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Crossover
- 主要目的
- Treatment
- 盲法
- Single (Outcomes Assessor)
盲法说明
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.
入排标准
- 年龄范围
- 18 Years 至 —（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •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.
排除标准
- •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).
研究组 & 干预措施
Sequence NO: Nasal oxygen first, then transoral oxygen
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).
干预措施: Transoral nasal cannula oxygen delivery (Other)
Sequence ON: Transoral oxygen first, then nasal oxygen
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).
干预措施: Transoral nasal cannula oxygen delivery (Other)
结局指标
主要结局
Incidence of hypoxemia during the oxygen delivery periods
时间窗: 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.
次要结局
- 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)
- Heart 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)
- Mean arterial pressure (MAP)(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)
- Airway plateau pressure(At the start and at the end of surgery)
- Positive end-expiratory pressure (PEEP)(At the start and at the end of surgery)
- Oral dryness score(Immediately after completion of each 10-minute oxygen delivery period)
- Overall comfort score(Immediately after completion of each 10-minute oxygen delivery period)
- Pharyngeal irritation / nausea score(Immediately after completion of each 10-minute oxygen delivery period)
- Length of PACU stay(From PACU admission to PACU discharge (up to 24 hours after surgery))
- Respiratory complications within 24 hours after surgery(Within 24 hours after surgery)
研究者
Shuai Wang
Deputy Chief Nurse
Nanjing First Hospital, Nanjing Medical University