Foreign body airway obstruction causing a ball valve effect

Abstract

Foreign body airway obstruction (FBAO) in adults is a rare but potentially fatal anaesthetic airway emergency. 1 Case description The authors present the case of a 29-year-old fit and well ASA I patient. Whilst consuming his morning coffee, he suddenly began to cough violently. He then became dysphonic and severely dyspnoeic, with the symptoms quickly resolving after a few minutes. The patient thought that he had choked on his coffee. He initially complained of a sore throat, an intermittent rasping voice and the presence of a foreign object sensation. As the symptoms did not subside after 2 h, he dialled the emergency services. He was taken to the resuscitation bay at the emergency department (ED) by ambulance for difficulty in breathing. He was immediately assessed by a junior trainee and was noted to appear comfortable and able to talk in full sentences. His observations were normal with no signs of respiratory compromise (respiratory rate of 12 bpm and SaO 2 99% on room air). There was no stridor or other signs of upper airway obstruction. A chest radiograph (Figure 1) was adjudged unremarkable with no obvious foreign body present , with perhaps few signs of hyperinflation. After discussion with a senior doctor at the ED, the patient was declared medically fit for discharge. However, prior to discharge the patient deteriorated and started to develop signs of a soft stridor with rasping on deep inspiration. He was referred to ENT surgery for suspected FBAO of the upper airway. As his condition was stable, flexible bronchoscopy was considered the most appropriate investigation under the care of the respiratory physicians. On examination in endoscopy, he was found to have an inverted plastic milk bottle cap beneath the level of the vocal cords (Figure 2). He was then transferred to the ENT theatres and consented for an urgent rigid bronchoscopy and subglottic foreign body removal under general anaesthesia. A succinct preoperative assessment espied him to be ASA I, with no past medical history, not a smoker, not taking any regular medications and being fasted for over 6 h. On arrival to theatre, two large bore IV cannu-lae were inserted. The patient was preoxygenated (with 100% oxygen), followed by a premedicaton with midazolam IV 2 mg and fentanyl in two 50 mg aliquots (due to his anxiety and musculature stature). A sevoflurane induction was then commenced to maintain spontaneous respiration. Judicious use of fentanyl was rationalized as it helped to obtund the laryngeal responses to instrumentation. Sevoflurane concentration was carefully increased to deepen anaesthesia with accentuation to maintain spontaneous respiration throughout. An i-gel Õ was inserted to assist with preoxygenation prior to rigid bronchoscopy. Anaesthesia was maintained by target controlled infusions of propofol (Cpt [target plasma concen-tration] 2-7 mg/ml) and remifentanil (Cpt 1-5 ng/ ml). When anaesthesia was deepened to an adequate depth, the i-gel Õ was removed, and the rigid bronchoscope inserted by the ENT surgeon. Oxygenation was maintained by apnoeic insuffla-tion of 100% oxygen through the side arm of the bronchoscope. High-frequency jet ventilation (HFJV) and surgical tracheostomy were immediately amenable should the need have arisen. The larynx was visualized easily, and the milk cap was promptly removed through the vocal cords using forceps. This precipitated minor laryngospasm which was resolved with the DECLARATIONS