Dislodged Denture in a Patient on High-flow Nasal Cannula: A Rare Mechanical Complication

Abstract

A man in his 70s presented with dyspnea and a seizure, requiring intubation for suspected status epilepticus. Following extubation and treatment for a COPD exacerbation, persistent hypoxemia led to high-flow nasal cannula (HFNC) therapy. However, his condition worsened with increased work of breathing and inability to speak. Chest radiography revealed a dislodged denture in the upper airway. Emergency reintubation and removal of the denture led to rapid clinical improvement, and he was extubated the next day. While denture dislodgement has been reported with bag-mask ventilation and BiPAP, this is the first case associated with HFNC. This case underscores the need to assess for dentures in patients requiring advanced respiratory support to prevent such complications.

1. Introduction

High-flow nasal cannula (HFNC) delivers oxygen at flow rates exceeding 6 L/min through a nasal cannula, utilizing an air-oxygen blender and a heated humidification system.1 In addition to enhancing oxygenation, HFNC provides a low level of continuous positive airway pressure (CPAP), a physiologic effect first described by Locke et al. in 1993.1 While denture dislodgement has been reported in association with bilevel positive airway pressure (BiPAP),2 no such occurrences have been documented with HFNC therapy. We report the case of a male patient in his 70s with an acute exacerbation of chronic obstructive pulmonary disease (COPD) who developed acute hypoxic respiratory failure secondary to denture dislodgement during HFNC therapy. Emergent intubation and removal of the dislodged denture from the larynx were performed, leading to rapid clinical improvement.

2. Case report

A man in his 70s with a significant medical history including 35-pack-year smoking history, chronic obstructive pulmonary disease (COPD) (on Fluticasone/Umeclidinium/Vilanterol and as needed albuterol) with chronic hypoxemia on 2 L/min home oxygen, bronchogenic carcinoma of the right lung treated with Cyberknife therapy, epilepsy (on valproate and levetiracetam), dysphagia, syndrome of inappropriate antidiuretic hormone secretion (SIADH), atrial fibrillation (on apixaban), and hypertension (on amlodipine) presented to the emergency department with worsening dyspnea.

On arrival, he was hypoxic, requiring 100 % FiO₂ on bilevel-positive airway pressure (BiPAP) to maintain oxygen saturation >95 %. He was tachycardic at 140 bpm (normal: 60–100 bpm), tachypneic at 40 breaths/min (normal: 12–20 breaths/min), hypertensive at 177/101 mmHg (normal: <120/80 mmHg), and afebrile at 36.8 °C. Shortly after the presentation, the patient experienced a generalized tonic-clonic seizure with acute mental status deterioration, necessitating emergent intubation. He was noted to have dentures which were removed prior to intubation. Seizure management included lorazepam (4 mg IV), propofol sedation, and levetiracetam (3 g IV).

Initial imaging revealed no acute abnormalities on CT head. CT angiography of the head showed a stable 3 mm left middle cerebral artery aneurysm without ischemia or hemorrhage. A chest X-ray (Fig. 2) demonstrated chronic triangular scarring in the right upper lung field, consistent with prior imaging, but no evidence of acute consolidation. Laboratory findings included chronic hyponatremia at 129 mmol/L (normal: 135–145 mmol/L), elevated bicarbonate at 34 mmol/L (normal: 22–28 mmol/L), and neutrophilic leukocytosis, which increased from 17,000/mm³ to 32,000/mm³ (normal: 4500–11,000/mm³). A respiratory viral panel was negative. Electroencephalography (EEG) demonstrated moderate diffuse background slowing without seizure activity. Sedation was discontinued, and his mentation improved (was alert and cooperative), allowing for extubation to 2 L nasal cannula the following day. His denture was also replaced.

Fig. 2.

Radiographic imaging on admission following endotracheal intubation, showing the endotracheal tube in the appropriate position and no evidence of radiopaque foreign body in the airway.

The patient continued treatment for a COPD exacerbation but later developed worsening hypoxia (saturating 70s in nasal cannula), tachypnea, and tachycardia (up to 150 bpm). High-flow nasal cannula (HFNC) therapy was initiated at 50 % FiO2 and a flow rate of 50 L/min, leading to initial improvement. However, within hours, he experienced acute respiratory distress characterized by intercostal retractions and an inability to speak in full sentences. A chest X-ray revealed a dislodged denture in the upper airway (Fig. 1). Emergent intubation was performed, during which the denture was removed from the larynx.

Fig. 1.

Radiographic imaging demonstrating a dislodged denture in the laryngopharynx (blue arrow). The denture was visualized again during endotracheal intubation and successfully removed. This resulted in marked clinical improvement, with the patient extubated within 24 h of intervention.

Following this intervention, the patient’s oxygenation stabilized on minimal ventilator settings, and he was extubated the next day to 2 L/min nasal cannula, his baseline oxygen requirement. Sputum cultures grew Pseudomonas aeruginosa. He was treated for COPD exacerbation with bronchodilators, a 5-day course of corticosteroids, and a 7-day course of levofloxacin. The patient was discharged on hospital day 8 on his home medications, including levetiracetam and valproate.

3. Discussion

High-flow nasal cannula (HFNC) is an alternative to conventional oxygen therapy. It consists of an air/oxygen blender connected to an active humidifier, delivering gas to the nasal cannula with independent adjustment of the fraction of inspired oxygen (FiO2) regardless of flow rate and gas mixture composition.3 HFNC provides a high flow of heated (37 °C), humidified (44 mg/L) gas at rates of 20–60 L/min with an FiO2 range of 21 %–100 %.4 The physiological effects of HFNC include increased mean airway pressure, enhanced end-expiratory lung volume, and improved oxygenation, with optimal effects typically achieved at higher flows of 40–60 L/min.4 Even at lower flows (20–45 L/min), HFNC has been shown to facilitate dead space washout, reduce work of breathing, and decrease respiratory rate.4

The delivery of heated, humidified gas prevents ciliary dysfunction, reduces inflammatory responses associated with dry and cold gases, mitigates epithelial cell damage, and maintains airway hydration, thereby preventing thickening of bronchial secretions.5 Additionally, HFNC aids in the washout of carbon dioxide (CO2) from the pharyngeal dead space, which constitutes approximately 30 % of total anatomical dead space.5 Furthermore, HFNC generates a mild expiratory pharyngeal pressure (up to 8 cm H2O), which decreases to zero during inspiration, resembling a pursed-lip breathing pattern that prolongs expiratory time and reduces expiratory flow limitation and dynamic hyperinflation.5 This mechanism also helps stabilize FiO2 delivery.5

While non-invasive ventilation (NIV) can be associated with complications such as mask intolerance, airway dryness, and air leakage, a rare but serious complication observed in our patient was denture dislodgement.6 Denture dislodgement typically occurs during activities such as eating, but has also been reported during endotracheal intubation, dental procedures, and orofacial trauma.2 To date, only one reported case of complete denture dislodgement with NIV exists. In that case, an 81-year-old patient developed stridor approximately 50 min after BiPAP initiation, and subsequent neck radiography revealed an impacted denture in the hypopharynx.2 In our case, the denture was removed prior to the initial intubation but was reinserted once the patient’s mental status improved. However, when his oxygen requirements increased and he was transitioned to high-flow nasal cannula (HFNC), the denture was not removed. Within hours of initiating HFNC, the patient experienced denture dislodgement. We hypothesize that the increase in pharyngeal pressure generated by non-invasive ventilation, including HFNC, contributed to the dislodgement of the denture in our patient.

Although not commonly associated with HFNC, denture ingestion can lead to severe complications such as gastrointestinal perforation and tracheoesophageal fistula formation.7 Cunniffe et al. described a case where a dislodged denture was found in the larynx eight days after general anesthesia, following worsening symptoms of hemoptysis, hoarseness, and dysphagia.8 Similarly, Chin and Ellul reported an impacted partial denture diagnosed one month after emergent intubation, presenting as dysphagia.9

Learning points

1. HFNC provides physiological benefits such as improved oxygenation, dead space washout, and work of breathing reduction, with optimal effects achieved at higher flow rates.

2. While NIV is commonly associated with complications like mask intolerance and air leaks, denture dislodgement is a rare but serious occurrence that can lead to airway obstruction or ingestion-related complications.

3. Clinicians should routinely check for and remove dentures in patients presenting with respiratory complaints, particularly if non-invasive ventilation is required.

Funding Statement

Primary funder is MedStar Georgetown Univerwsity Hospital (Baltimore) Program.