A 44-year-old man with a medical history of food allergy to peanuts is brought to the emergency department for an allergic reaction. The patient developed the acute onset of dyspnea and wheezing shortly after ingesting a cookie. His symptoms progressed to difficulty swallowing and swelling of the face and tongue. On arrival, temperature is 36.9 C (98.4 F), pulse is 115/min, blood pressure is 85/74 mm Hg, and respirations are 28/min. Oxygen saturation is 93% on a nonrebreather face mask. He is anxious and pale with swollen lips, swollen tongue, and inspiratory stridor. On lung auscultation, bilateral wheezing is present. Intramuscular epinephrine, intravenous fluids, and racemic epinephrine via nebulizer are administered without improvement. The patient's distress is increasing, and he is becoming more agitated. The decision to intubate using awake fiberoptic nasotracheal intubation is made. Which of the following medications would be the best choice to aid in awake fiberoptic nasotracheal intubation in this patient?

Question

A 44-year-old man with a medical history of food allergy to peanuts is brought to the emergency department for an allergic reaction.  The patient developed the acute onset of dyspnea and wheezing shortly after ingesting a cookie.  His symptoms progressed to difficulty swallowing and swelling of the face and tongue.  On arrival, temperature is 36.9 C (98.4 F), pulse is 115/min, blood pressure is 85/74 mm Hg, and respirations are 28/min.  Oxygen saturation is 93% on a nonrebreather face mask.  He is anxious and pale with swollen lips, swollen tongue, and inspiratory stridor.  On lung auscultation, bilateral wheezing is present.  Intramuscular epinephrine, intravenous fluids, and racemic epinephrine via nebulizer are administered without improvement.  The patient's distress is increasing, and he is becoming more agitated.  The decision to intubate using awake fiberoptic nasotracheal intubation is made.  Which of the following medications would be the best choice to aid in awake fiberoptic nasotracheal intubation in this patient?

Quizplus · Accepted Answer

Explanation: This patient with acute onset of respiratory distress, angioedema, and shock following likely allergen exposure has anaphylaxis and an unstable respiratory status (eg, tachypnea, hypoxia, stridor, wheezing) that are worsening despite appropriate treatment. This situation necessitates a definitive airway. In contrast to rapid sequence intubation (RSI), awake intubation (either nasotracheal or orotracheal) is the preferred method of intubation for patients with difficult airways, such as this patient with upper airway obstruction (eg, swollen lips/tongue, stridor). In awake intubation, the patient independently maintains upper airway tone and spontaneous ventilation while the airway is visualized (typically using a fiberoptic endoscope) to determine whether intubation is possible. During RSI, a patient is fully anesthetized and paralyzed, causing loss of all upper airway tone, protective airway reflexes, and respiratory drive. If intubation is unsuccessful, as can occur in patients with difficult airways, the patient can rapidly become hypoxic and experience cardiac arrest. Ketamine, a phencyclidine derivative, is the preferred agent to use for awake intubations because it provides dissociation, amnesia, and analgesia (ie, dissociative anesthesia) while maintaining upper airway tone, protective airway reflexes, and respiratory drive. It also causes a sympathetic surge (by inhibiting reuptake of catecholamines) that increases blood pressure and causes bronchial smooth muscle relaxation, which are additional benefits in this patient with hypotension and bronchospasm. (Choice A) Fentanyl is a short-acting opioid analgesic sometimes used for pain management during short procedures (eg, fracture reduction). However, fentanyl can cause respiratory depression and exacerbate hypotension, making it undesirable in this patient. In addition, it does not provide dissociation or amnesia. (Choice C) Propofol can provide rapid-onset sedation and amnesia. However, it typically causes deep sedation, respiratory depression, and loss of airway reflexes, which would be dangerous in this patient. In addition, it can worsen hypotension. (Choices D and E) Rocuronium and succinylcholine are neuromuscular blocking agents typically used (along with a sedative) in RSI. Both cause complete paralysis, loss of upper airway tone, and cessation of all respiratory effort, which can lead to hypoxia and cardiac arrest if an airway is not secured immediately. This patient with a difficult airway should instead undergo awake intubation, with preservation of spontaneous breathing (vs paralysis). Educational objective: Awake intubation is the preferred intubation method for patients with difficult airways (eg, upper airway obstruction due to anaphylaxis). Ketamine facilitates awake intubation by providing dissociation, amnesia, and analgesia while also maintaining upper airway tone, protective reflexes, and respiratory drive. References: Ketamine activates breathing and abolishes the coupling between loss of consciousness and upper airway dilator muscle dysfunction. (http://www.ncbi.nlm.nih.gov/pubmed/22108392)

A 44-Year-Old Man with a Medical History of Food Allergy