Abstract
Background
Airway obstruction is an emergent, life-threatening condition and could contribute to the difficult airway[1]. A patient with upper airway obstruction can present with a complaint of cough, stridor, hoarseness of voice, and respiratory distress [2]. A well-rehearsed, clearly-led and protocolised airway management plan is crucial. In general, airway management is one of the fundamental skills of an emergency physician. We report a case describing the management of a patient with severe upper airway obstruction and altered mental status due to respiratory failure and impending respiratory arrest.
Case presentation
A 52-year-old gentleman was brought to our emergency department (ED) via emergency medical services (EMS) with a pre-alert notification of airway obstruction that might require intubation. On arrival to our ED, the patient was in severe distress with audible stridor. Vital signs were documented as showing a tachypnoea with a respiratory rate of 32/minute, heart rate of 107 beats per minute, and a blood pressure of 175/97 mmHg. His Glasgow coma score (GCS) was recorded as 5/15. He was receiving oxygen via a 15 l/min non-rebreather mask.
An arterial blood gas pre intubation showed a pH of 7:06, undetectable CO2, undetected HCO3 and O2 level of 326 mmHg.
Upon examination, an anterior firm neck mass was noted in the midline.
A decision was made to intubate the patient in view of imminent arrest due to airway obstruction. A plan consistent with the difficult airway society algorithm, as suggested by the Difficult Airway Society (DAS) was discussed.
Plan A – video laryngoscopy with sedation medication only
Plan B – Plan A with bougie If failed, plan B was bougie. Call for help
Plan C – Use Intubating LMA
Plan D – Front of neck access with cricothyroidotomy
Intubation was unsuccessful with video laryngoscopy and bougie assistance.
We called for help from the anaesthesia department. They were also unsuccessful intubating and recommended emergent ENT intervention. Throughout this process, we were able to ventilate the patient.
Eventually, the patient was intubated using a bougie and a smaller size endotracheal tube (size 5.0). A CT scan revealed a laryngeal mass from the glottic region with signs of necrosis and infiltration to the adjacent neck muscles. The patient underwent an emergent tracheostomy followed by a total laryngectomy and was commenced on chemotherapy.
Discussion
The incidence of a difficult airway in the ED has been reported from 3-5.3% and failed intubation to be 0.5-1.2% [1] The difficult airway has been defined as an airway complicated by anatomical, physiological, or trauma related reasons. In contrast a failed airway has been variably defined and includes objective criteria like inability to achieve endotracheal intubation on 3 attempts by a skilled provider or a ‘cant intubate/cant oxygenate’ scenario. [1] Early recognition and intervention with a good airway plan is crucial in such cases. Indications for emergency airway management are less well-defined but broadly include airway obstruction, inability to maintain/protect an airway, and impending/established respiratory failure.
It is helpful to vocalise one’s mental model as part of preparation for the difficult airway. An intubation checklist list can help collate preparation including a plan for the ‘Can’t intubate, can’t ventilate’ scenario and serve as a cognitive aid. Despite the lack of high quality evidence for their use in ED, airway checklists have been shown to decrease complications from intubation related complications [2].
Preoxygenation is key in emergency airway management and has been demonstrated to prolong the time to desaturation [3]. Delayed sequence intubation has also been described though initially only the induction agent is administered. This follows a period of oxygenation, followed by administration of the paralytic agent [4]. Apneoic oxygenation relies on administration of high flow oxygen through a nasal cannula, sometimes, in addition to a face mask, and is shown to also delay desaturation during apnea following paralysis [5].
When the patient does not have a suspected cervical spine injury, positioning of the airway improves visualisation of the glottis. The ‘Head Elevated Laryngoscopy (HELP)’ – or the ramp position – are one such example where access to the laryngeal inlet can be improved.
Ketamine, etomidate, and midazolam are known to have a lower negative hemodynamic effect compared to other drugs. However, it is acknowledged, an ideal induction agent for the difficult airway does not exist [1].
It should be mentioned here that awake intubation using topical local anesthetics on the airway followed by fibre-optic intubation is usefully indicated in the ‘Can’t intubate, can’t ventilate’ scenario [6].
The commonest paralytic agents used in the difficult airway include succinyl choline and rocuronium. Historically, succinyl choline has been correlated with better intubating conditions, however, rocuronium at dose of 1.2 mg/kg offers comparable results [7].
Direct laryngoscopy has been used for tracheal intubation since the late 19th century. It is worth remembering external laryng