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Purpose: Intravenous sedation (IVS) with propofol (PPF) is commonly performed in dental treatment, particular in patients with dentophobia, with gag reflex, or undergoing implant surgeries, as PPF has the advantages of rapid induction and recovery. However, PPF and other intravenous sedatives may cause respiratory depression. Thus, IVS with PPF requires oxygen administration. But airway burn may occur when high-concentration oxygen is stored in the oral cavity and catches fire. For these reasons, the present study aimed to elucidate the changes in oxygen concentration (OC) under IVS with PPF and oxygen administration. Patients and methods: Nineteen healthy male volunteers participated in the study. None of them had missing teeth, nasal congestion, or temporomandibular joint dysfunction. They were sedated with a continuous PPF infusion dose of 6 mg/kg/hr for 25 min, followed by administration of 3 L/min oxygen via a nasal cannula. The OC was measured at two sites, namely, the median maxillary anterior teeth (MMAT) and median maxillary soft palate (MMSP), before PPF infusion (baseline) and 14, 15-18 (Term 1), 19, and 20-23 (Term 2) min after the start of infusion. Results: Compared with the values at baseline, the OC in the MMSP significantly increased at each time point, whereas the OC in the MMAT significantly increased at Term 2. Furthermore, in the comparison of the OC before and after the use of a mouth prop, the OC exhibited an upward trend, but no statistically significant differences were observed between the two time points in the MMAT and MMSP. In IVS with PPF and oxygen administration, the OC in the pharynx increases as the sedative level deepens. Conclusion: Oxygen administration should be temporarily discontinued, and suction should be performed to decrease the OC in the oral cavity when sparking procedures during IVS with PPF and oxygen administration are performed.

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Operating theatre fires are rare but can result in significant morbidity. A 76-year-old male with complex airway disease sustained superficial facial burns during an elective airway debulking procedure. His airway was being managed with high-flow nasal oxygen at 70 l.min-1 and FiO2 1.0 delivered by Optiflow™ (Fisher and Paykel Healthcare Limited, Auckland, New Zealand). When suction monopolar diathermy was used to excise hyperkeratotic tissue beside his epiglottis, an arc was created to the tip of the suspension laryngoscope, followed by a jet of flame as the Optiflow circuit ignited. This resulted in burns to the patient's face and shoulder. He required admission to the intensive care unit and had a complicated postoperative course that included the need for surgical tracheostomy to facilitate weaning from mechanical ventilation. This case highlights the dangers of using high-flow nasal oxygen alongside an ignition source.

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PURPOSE: An estimated 34 % of reported operating room fires involve the airway. Despite the inherent risks in otolaryngologic surgery, education regarding prevention and management of airway fires is limited in graduate medical training. One contributing factor is a lack of reporting of such rare events in our literature. METHODS: The U.S. Food and Drug Administration's Manufacturer and User Facility Device Experience database was queried for reports of adverse events related to fires occurring during surgical procedures of the airway from January 1, 2010, to March 31, 2020. RESULTS: 3687 reports were identified and 49 unique reports of airway fire were included. Sustained fires were described in 16 (32.7 %) reports and 33 (67.3 %) described transient flares. 2 fires extended beyond the airway and 9 (18.4 %) were noted to have occurred at the start of the case. Fires were reported most commonly during tonsillectomy (n = 22 [44.9 %]), vocal fold excision (n = 5 [10.2 %]), and adenoidectomy (n = 4 [8.2 %]). 46 reports attributed flare initiation to a specific element of the fire triangle. 16 patient and 2 operator injuries were reported. Saline washing was utilized in 7 (14.3 %) cases overall. Patients were extubated immediately in 2 (12.5 %) of the 16 reports of sustained fires. 0 mortalities were reported. CONCLUSION: Airway fires were reported in a variety of upper airway procedures performed regularly by otolaryngologists. The triggering factor that led to fire was identified as a spark or char in about half of the reported cases, and only 2 reports described immediate removal of the endotracheal tube.

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Objective: Airway fires are a rare but devastating complication of airway surgery. Although protocols for managing airway fires have been discussed, the ideal conditions for igniting airway fires remain unclear. This study examined the oxygen level required to ignite a fire during a tracheostomy. Study Design: Porcine Model. Setting: Laboratory. Methods: Porcine tracheas were intubated with a 7.5 air-filled polyvinyl endotracheal tube. A tracheostomy was performed. Monopolar and bipolar cautery were used in independent experiments to assess the ignition capacity. Seven trials were performed for each fraction of inspired oxygen (FiO2): 1.0, 0.9, 0.7, 0.6, 0.5, 0.4, and 0.3. The primary outcome was ignition of a fire. The time was started once the cautery function was turned on. The time was stopped when a flame was produced. Thirty seconds was used as the cut-off for "no fire." Results: The average time to ignition for monopolar cautery at FiO2 of 1.0, 0.9, 0.8, 0.7, and 0.6 was found to be 9.9, 6.6, 6.9, 9.6, and 8.4 s, respectively. FiO2 ≤ 0.5 did not produce a flame. No flame was created using the bipolar device. Dry tissue eschar shortened the time to ignition, whereas moisture in the tissue prolonged the time to ignition. However, these differences were not quantified. Conclusion: Dry tissue eschar, monopolar cautery, and FiO2 ≥ 0.6 are more likely to result in airway fires.

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High-flow nasal oxygen (HFNO) has been used in "tubeless" shared-airway surgeries but whether HFNO increased the fire hazard is yet to be examined. We used a physical model for simulation to explore fire safety through a series of ignition trials. An HFNO device was attached to a 3D-printed nose with nostrils connected to a degutted raw chicken. The HFNO device was set at twenty combinations of different oxygen concentration and gas flow rate. An electrocautery and diode laser were applied separately to a fat cube in the cavity of the chicken. Ten 30 s trials of continuous energy source application were conducted. An additional trial of continuous energy application was conducted if no ignition was observed for all the ten trials. A total of eight short flashes were observed in one hundred electrocautery tests; however, no continuous fire was observed among them. There were thirty-six events of ignition in one hundred trials with laser, twelve of which turned into violent self-sustained fires. The factors found to be related to a significantly increased chance of ignition included laser application, lower gas flow, and higher FiO2. The native tissue and smoke can ignite and turn into violent self-sustained fires under HFNO and continuous laser strikes, even in the absence of combustible materials. The results suggest that airway surgeries must be performed safely with HFNO if only a short intermittent laser is used in low FiO2.

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BACKGROUND: An airway-associated fire in an operating room can have devastating consequences for patients. Breathing circuit warmers (BCWs) are widely used to provide heated and humidified anesthetic gases and eventually prevent hypothermia during general anesthesia. Herein, we describe a case of a BCW-related airway fire. CASE PRESENTATION: In this case, an electrical short within a BCW wire caused a fire inside the circuit. Simultaneously, the fire was extinguished, ventilation was stopped, and the endotracheal tube was disconnected from the BCW. The patient was exposed to the fire for less than 10 s, resulting in burns to the trachea and bronchi. Immediately after airway burn, bronchoscopy showed no edema or narrowing except for soot in the trachea and both main bronchus. After the inhalation burn event, prophylactic antibiotics, bronchodilator, mucolytics nebulizer, and corticosteroid nebulizer were started. On bronchoscopy 3 days after the inhalation burn, mucosal erythematous edema was observed and the inflammatory reaction worsened. The inflammatory reaction showed aggravation for up to 2 weeks, and then gradually recovered, and the epithelium and mucous membrane of the upper respiratory tract returned to normal after 4 weeks. Eventually, the patient recovered without long-term complications and was successfully discharged. CONCLUSIONS: This is the first report of a fire caused by BCW. We wanted to share our experience of how we responded to an airway-related fire in an OR and treated the patient. It cannot be overemphasized that the electrical medical appliance associated with the airways are fatal to the patient in the event of a fire, so caution should always be exercised.

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High-flow nasal oxygen is increasingly used in complex head and neck surgical procedures and difficult airway management. We describe a case where an operating room fire occurred while using high-flow nasal oxygen during an awake tracheostomy for an obese patient in airway extremis due to supraglottitis. Shortly after the operation began, and before incision of the trachea, electrical diathermy applied to bleeding sub-cutaneous vessels ignited a small flame. This was extinguished without harm to the patient and the procedure was completed without further complication. Fire requires three components: fuel; heat; and an oxidiser. We speculate that high-flow oxygen channelled under the drapes and acted as the oxidiser; either tissue eschar or vapourised fat were the fuel; and the diathermy supplied a source of ignition to complete the fire triad. When using high flows of concentrated oxygen, practitioners should aim to minimise all of these factors and be alert for the risk of fire at every stage of the operation.

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Anesthesiologists and otolaryngologists share the airway in an elegant ballet that requires communication, collaboration, and mutual respect. This article addresses principles to prevent or manage challenging conditions such as airway fires, anatomically difficult airways, and post-tonsillectomy hemorrhage. Discussion includes rationales for the use of simulation and resilience engineering principles to achieve the safest patient care.

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Airway narrowing can be idiopathic or can occur as a result of airway tumors, hematomas, infections, and other pathologic conditions. Endoscopic management variously involves balloon dilatation, stent placement, laser vaporization of pathologic tissue, microdebridement, and other interventions, using either a rigid or a flexible bronchoscope. Jet ventilation is frequently used in such settings, especially when the presence of an endotracheal tube would interfere with the procedure. In desperate cases, extracorporeal membrane oxygenation may be used in managing the critical airway.

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As more surgeries are moving out of the hospital setting, effective emergency response in freestanding ambulatory surgery centers requires organized preparedness. Rapid, consistent emergency response can be challenged by their rarity of occurrence, fast-paced environment, and relative lack of resources. Anesthesiologists who practice in these settings must be aware of the differences between the management of an anesthetic emergency in the hospital with virtually unlimited resources and staff, versus an ambulatory surgery center with limited resources and slightly different goal: stabilization and transfer of care. Regular simulation-based training schedules are effective for ambulatory surgery center preparedness for emergency response.

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Otolaryngologists are at high risk of surgical fire. During surgery in the head and neck region there is close proximity of 3 essential elements: an ignition source, a fuel, and an oxidizing agent. In this article, the authors highlight the scenarios where fire may occur and offer steps that surgeons can take to minimize risk for their patients. By understanding the elements of the fire triad, otolaryngologists can decrease the risk of surgical fire, through careful control of oxidizers, ignition sources, and potential fuels in the operating room.

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We present the case of unanticipated airway ignition during hard palate biopsy. Transnasal humidified rapid-insufflation ventilatory exchange (THRIVE) and monopolar diathermy were utilised for the procedure, during which an arc arose from the diathermy tip to a titanium implant, causing a brief ignition on the monopolar diathermy grip. This case highlights the need for maintained awareness of fire risk when using diathermy in the presence of THRIVE during airway surgery.

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BACKGROUND: The laryngeal mask airway is increasingly used as an airway adjunct during general anesthesia. Although placement is generally simpler than an endotracheal tube, complete sealing of the airway may not occur, resulting in contamination of the oropharynx with anesthetic gases. Oropharyngeal oxygen enrichment may be one of the contributing factors predisposing to an airway fire during adenotonsillectomy. The current study prospectively assesses the oropharyngeal oxygen and volatile anesthetic agent concentration during laryngeal mask airway use in infants and children. METHODS: Following the induction of general anesthesia and placement of a laryngeal mask airway, the oropharyngeal gas sample was obtained by placing a 14-gauge catheter attached to the gas sampling tube into the oropharynx above the laryngeal mask airway. The oropharyngeal concentration of the oxygen and the anesthetic agent were recorded for five breaths during both spontaneous ventilation (SV) and positive pressure ventilation (PPV). RESULTS: The study included 238 patients. The oropharyngeal concentration of sevoflurane was >50% of the inspired sevoflurane concentration during SV in 10 of 238 (4.2%) patients and during PPV in 135 of 238 (56.7%) patients. Similarly, during SV and PPV, the oropharyngeal oxygen concentration was >21% in 30 of 238 (12.6%) patients and in 188 of 238 (79%) patients, respectively. Significantly, we also noticed that the oropharyngeal oxygen concentration exceeded 50% in 5 of 238 (2.1%) patients during SV and in 139 of 238 patients (58.4%) patients during PPV. CONCLUSIONS: With the use of a laryngeal mask airway and the administration of 100% oxygen, there was significant contamination of the oropharynx during both PPV and SV. The oropharyngeal concentration of oxygen was high enough to support combustion in a significant number of patients. The use of a laryngeal mask airway does not ensure sealing of the airway and may be one risk factor for an airway fire during adenotonsillectomy.

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INTRODUCTION: Twenty-five cases of airway fire during tracheostomy have been reported in the literature. The authors describe a case observed in their centre 3 years ago, discuss the causes and preventive management and propose guidelines for prevention of this complication. CASE REPORT: A 66-year-old woman was intubated and ventilated with 100% oxygen during general anaesthesia for tracheostomy. On opening the trachea by monopolar diathermy, the oxygen present in the endotracheal tube caught fire, inducing combustion of the tube spreading to the lower airways. This airway fire was responsible for severe acute respiratory failure and the formation of multiple laryngotracheal stenoses. DISCUSSION: Combustion of the endotracheal tube due to ignition of anaesthetic gases induced by the heat generated by diathermy is responsible for airway fire. These various phenomena are discussed. Prevention is based on safety measures and coordination of surgical and anaesthetic teams.

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Therapeutic bronchoscopy is widely employed as an effective first-line treatment for patients with central airway obstructions. Airway fires during rigid bronchoscopy are rare, but can have potentially devastating consequences. Pulmonologist and anesthesiologist undertaking this type of procedure should be aware of this serious problem and be familiar with measures to avoid this possibly fatal complication. We report the case of a 24-year-old patient with a silicone stent who experienced an electrocautery-induced airway fire during rigid bronchoscopy.

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Therapeutic bronchoscopy is widely employed as an effective first-line treatment for patients with central airway obstructions. Airway fires during rigid bronchoscopy are rare, but can have potentially devastating consequences. Pulmonologist and anesthesiologist undertaking this type of procedure should be aware of this serious problem and be familiar with measures to avoid this possibly fatal complication. We report the case of a 24-year-old patient with a silicone stent who experienced an electrocautery-induced airway fire during rigid bronchoscopy.

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