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Acute Facial, Cervical, and Thoracic Subcutaneous Emphysema

1996; Lippincott Williams & Wilkins; Volume: 82; Issue: 4 Linguagem: Inglês

10.1097/00000539-199604000-00038

1526-7598

Michael G. Richardson, Joseph W. Dooley,

Airway Management and Intubation Techniques

Acute subcutaneous emphysema is an uncommon complication of tracheal intubation. Although usually of little clinical concern, it may cause life-threatening airway compromise [1,2]. We describe sudden subcutaneous emphysema during fiberoptic laryngoscopy. Case Report An 87-yr-old, 45-kg woman with severe cervical myelopathy was scheduled for decompressive laminectomy and cervical spine fixation. Magnetic resonance imaging revealed an odontoid fracture with C1-2 subluxation and cord compression Figure 1. We administered midazolam 2 mg and fentanyl 50 micro gram intravenously (IV), and applied phenylephrine and 2% lidocaine jelly topically to both nares. We gently attempted right blind nasotracheal intubation once but were unable to pass a 6.5 endotracheal tube (ETT) beyond the nasopharynx, likely owing to the airway deformity caused by cervical subluxation Figure 1. We then performed nasal fiberoptic laryngoscopy (LF-2; Olympus, Tokyo, Japan). Oxygen from the auxiliary supply of the anesthesia machine was insufflated intermittently through the fiberscope suction channel. There was no evidence of trauma, and the trachea was easily intubated with a 6.5 ETT. Anesthesia was induced with etomidate 10 mg and vecuronium 5 mg IV, and maintained with nitrous oxide and isoflurane. The patient received fentanyl 200 micro gram during the first hour. Two hours after induction of anesthesia, she had four equal twitches of the adductor pollicis. The procedure was completed in 3 h, and her trachea was extubated after administration of neostigmine 1 mg with glycopyrrolate 0.15 mg IV. She was awake, moving all extremities in the postanesthesia care unit, with pulse oximeter saturation 98% while breathing 2 L/min oxygen via nasal cannula.Figure 1: Sagittal cervical spine magnetic resonance image showing Type 2 odontoid fracture with C1-2 subluxation and cord compression at the C-1 level (arrow). The cervical subluxation distorts the normal anatomy of the posterior nasopharynx.One hour after extubation, the patient developed progressive inspiratory obstruction with accessory respiratory muscle use and inspiratory thoracic retractions. Neostigmine 1 mg with glycopyrrolate 0.15 mg was given IV without effect. Obstruction was unrelieved by mandibular elevation and insertion of a 7.0 nasal airway. Obstruction was relieved by positive end-tidal pressure from a mask. Nasal fiberoptic examination using the same model fiberscope as previously described revealed no trauma, but with each inspiration, the hypopharyngeal soft tissue collapsed inward and the epiglottis fell posteriorly, obstructing the glottis and hindering fiberscope passage. After several attempts through both nares, a second anesthesiologist attempted fiberoptic tracheal intubation through the right naris. Oxygen delivered from the wall pipeline supply (50 psi) with a flow of 5 L/min (flow meter regulator) via oxygen tubing was insufflated by intermittent thumb occlusion of the fiberscope channel post. During oxygen insufflation with the fiberscope tip in the nasopharynx, the patient's right face, neck, thorax, and proximal right upper extremity abruptly developed massive swelling. Palpation revealed crepitus suggestive of acute subcutaneous emphysema. The patient's oxygen saturation decreased to 77%, but increased to 95% with positive endtidal pressure from a mask using 100% oxygen. The trachea was then intubated with a 6.5 ETT via retrograde wire technique. Chest radiograph revealed bilateral thoracocervical subcutaneous emphysema Figure 2. Otolaryngology consultation was obtained in the intensive care unit. Ceftriaxone was administered prophylactically, and her trachea was extubated 10 h later. Fiberoptic examination by the otolaryngologist revealed a puncture laceration of the posterior nasopharyngeal wall. She had diffuse hypopharyngeal swelling and poor hypopharyngeal tone with partial collapse, yet was judged to have an adequate airway. A day later, she developed acute airway obstruction during feeding tube placement and required tracheal reintubation. The patient subsequently underwent tracheostomy and was recovering well until she died on postoperative day 21 from a massive cerebrovascular accident.Figure 2: Anterioposterior chest radiograph obtained shortly after intubation, revealing massive bilateral thoracic and cervical subcutaneous emphysema.Discussion Both subcutaneous and mediastinal emphysema may occur after interruption of respiratory or upper gastrointestinal mucosa. A pressure difference across the interrupted membrane may force gas into underlying tissue with dissection along fascial planes [1]. Subcutaneous and mediastinal emphysema have occurred after esophageal perforation [3], transbronchial biopsy [4], blunt trauma [5-7], tracheal intubation via direct [3,6,8-12] and retrograde [13] techniques, transtracheal and translaryngeal jet ventilation [14,15], and positive pressure ventilation [16,17]. In our patient, sudden, massive subcutaneous emphysema occurred acutely during fiberoptic examination, a technique associated with minimal potential for trauma. Oxygen insufflation through the fiberscope (5 L/min) was the likely cause, although this is commonly recommended to defog the lens, clear secretions, and increase the fraction of inspired oxygen [18,19]. Five liters of oxygen per minute is an acceptable flow for this purpose [18]. Oxygen sources most commonly used are the machine auxiliary oxygen supply and the wall pipeline supply. Should the fiberscope tip become completely occluded (no flow), the maximum pressure achievable within the closed system is that proximal to the pressure-compensated flow regulator. With either wall pipeline or Narkomed (North American Drager, Telford, PA) machine auxiliary oxygen supplies, that pressure is 45-50 psi. If the fiberscope tip abuts against respiratory mucosa, causing occlusion of the insufflation port, the mucosa may potentially be subjected to oxygen pressure great enough to cause rapid submucosal injection of oxygen, as occurred in this case. The puncture laceration of the posterior nasopharynx noted the next day was the only detectable interruption in upper respiratory mucosa and may have been the entry site for subcutaneous gas. If so, mucosal trauma may have occurred at any point during airway management--initial blind nasal intubation attempt, nasal airway placement, or fiberscope manipulation. That it occurred during fiberoptic laryngoscopy would suggest that either the fiberscope caused mucosal trauma or the fiberscope tip entered a preexisting defect. Submucosal extension of subcutaneous emphysema has caused life-threatening upper airway obstruction [1,2], restriction of ventilation [5], and serious infectious morbidity [3,8]. Anesthesiologists performing fiberoptic airway instrumentation with oxygen insufflation should be aware of subcutaneous emphysema as a potential complication and should be prepared to manage associated consequences. The authors are grateful to Denham S. Ward, MD, PhD, for his assistance in the preparation of this manuscript.