Views:5 Author:Site Editor Publish Time: 2017-09-22 Origin:Site
Airway adjuncts such as oral or nasopharyngeal airways (NPAs) are a staple of basic airway management. Placed countless times daily in the United States by providers from a wide range of backgrounds, these devices can be critically important in relieving airway obstruction that causes respiratory arrest. Tissue or dental trauma can occur with placement, but the risk for mig ration of the device itself into the patient’s airway is rarely considered, let alone encountered. Cleaning or manipulating tracheostomy tubes is a known risk factor for foreign body aspiration,1 but the classic clinical picture of cough and dyspnea with cyanosis2 is readily masked during anesthesia. Further, during initial emergent resuscitative efforts in the operating room (OR), historical details may be lacking altogether. Here we present an unusual case of NPA migration into the trachea of a patient with a known laryngeal mass.
A 57-year-old, morbidly obese man recently diagnosed with stage IV squamous cell carcinoma of the supraglottic larynx was found down in his home by his wife, who called 911. Emergency medical services transported the patient via ambulance while performing CPR, with one documented failed intubation attempt. In the emergency department, attempts to mask ventilate were ineffective for maintaining oxygenation, and the surgical team brought the patient emergently to the OR for a tracheostomy.
The surgical team successfully placed a size 8 cuffed Shiley tracheostomy tube (Medtronic) after significant defatting of the operative site, with subsequent stabilization of his respiratory status. The patient’s condition remained tenuous, with the occurrence of a non-ST elevation myocardial infarction during the first few days of his ICU stay. On postoperative day 4, ventilation of the patient via the tracheostomy tube became more difficult, and suctioning of the trachea also was noted to be markedly difficult.
Bedside flexible bronchoscopy via the tracheostomy tube revealed a green foreign body in the trachea obstructing the lumen. The surgical team then immediately requested transfer to the OR for emergent retrieval of the foreign body.
The anesthesiology team—comprising the attending anesthesiologist and a first-year anesthesiology resident—transported the patient from the ICU to the OR, allowing spontaneous ventilation at 100% oxygen delivered via direct connection of a bag-valve-mask apparatus to the tracheostomy tube. Positive-pressure ventilation was intentionally avoided to circumvent further migration of the foreign body, with permissive reduction in blood saturation levels but maintaining a level above 80%.
Once in the OR, general anesthesia was induced using 140 mg of propofol and 200 mg of succinylcholine, with ear, nose, and throat (ENT) surgeons at bedside. A succinylcholine infusion was prepared but not started, while the ulnar nerve was stimulated supramaximally with repeated train of four (TOF) monitoring (interval, 10 seconds; frequency, 2 Hz) via surface electrodes at the wrist. After complete loss of twitches, a rigid bronchoscope was advanced by the surgeon through the oropharynx and glottis to the level of the tracheostomy tube.
During this time, the patient was ventilated through the bronchoscope via the anesthetic circuit at 100% oxygen. The ENT surgeon advanced forceps into the trachea via the rigid bronchoscope and successfully retrieved the foreign body. Further examination revealed that the foreign body was a 26 Fr nasal airway (Figure).
Figure. The retrieved foreign body, which was a 26 Fr nasal airway.
Tracheal foreign body aspiration affects children more often than adults. Anesthetic management of the removal of a tracheal foreign body should ensure adequate ventilation and oxygenation as well as optimal operating conditions. The use of rigid bronchoscopy to remove the nasal trumpet from the airway in this case allowed for the use of instruments with sufficient clamping force to remove such a large object. Anesthetic management during this time is a balance of maintaining spontaneous ventilation when possible to avoid migration of the foreign body while quickly providing positive-pressure ventilation when needed.
Flexible bronchoscopy also is used increasingly in the retrieval of tracheal foreign bodies in adults.3,4 Some flexible bronchoscopes have large channels that permit suctioning of smaller foreign bodies from the distal airways. One limitation is increased resistance to ventilation due to the partial obstruction of the endotracheal tube by the scope. Regardless, it is crucial that personnel and equipment be available to immediately proceed with rigid bronchoscopic extraction of the foreign body should flexible bronchoscopy fail.
In this case, a succinylcholine infusion was planned to ensure continuous paralysis during the procedure after the initial intubating dose. Fortunately, the nasal airway was retrieved quickly, using only the paralysis resulting from the initial dose. However, the advantage of succinylcholine via infusion or bolus dose in this case is the same: rapid paralysis necessary to ensure safe passage of the rigid scope along with quick recovery with no muscle weakness postoperatively, with the possibility of returning the patient to spontaneous ventilation very quickly. Depolarizing blockade, or phase I block, presents with no fade to TOF nerve stimulation.
One complication associated with succinylcholine is the unpredictable occurrence of phase II block, characterized by fade to TOF, a gradual diminution of evoked response during prolonged or repeated nerve stimulation.5 Phase II block is defined as a 50% reduction of the fourth TOF response.6,7 The likelihood of this type of blockade grows along with increasing total dose; thus, the risk increases with the length of the procedure.
In this case, the bolus dose was sufficient. However, a short infusion of succinylcholine would have provided good operating conditions with little risk for phase II block given the short duration of the procedure. Regardless, the use of succinylcholine provided the best chance to return the patient to spontaneous ventilation if controlled ventilation became impossible.
A review of the literature reveals a few cases of NPA aspiration.8-10 In this case, the diagnosis was confounded by the presence of multiple, much more likely etiologies of respiratory failure. The known history of laryngeal cancer coupled with morbid obesity masked this very unusual cause of tracheal obstruction.
Caution should be exercised whenever an NPA is placed to prevent its distal migration. Several strategies have been described, including the use of an endotracheal tube connector fitted snugly into the flared proximal end of the nasal airway, which is then further secured with tape to the external nose, just as with a nasal endotracheal tube. This particular approach allows suctioning via the nasal airway, which is impeded by other techniques, such as the placement of a safety pin through the flange.11
One other potential consideration is whether dilation from a previously placed nasotracheal tube may expand the size of the nasal passage, thus making aspiration more likely if the NPA is subsequently placed in the same side.12 This case should promote careful attention to ensure appropriate NPA sizing and securement, as well as careful documentation of placement so that prompt recognition of aspiration may occur.