The patient did not have an asthmatic attack in the operating room and you proceed with induction. How would you induce anesthesia? Would you use a supraglottic airway instead of an endotracheal tube?
Answer:
The principles of anesthetic management for the asthmatic patient are threefold: to block airway reflexes before laryngoscopy and intubation, to relax airway smooth muscle, and to prevent release of biochemical mediators.
Before induction of general anesthesia, the patient should take two or three puffs of albuterol from a metered-dose inhaler (MDI). Propofol is often used for induction of hemodynamically stable asthmatic patient. Ketamine may be chosen in a hemodynamically unstable patient with asthma (see sections C.3) and C.4). Then, oxygen and a potent inhalation agent, such as sevoflurane, are administered by mask to achieve an adequate depth of anesthesia that suppresses hyperreactive airway reflexes sufficiently to permit tracheal intubation without triggering bronchospasm. The lesser pungency of sevoflurane (compared with desflurane and isoflurane) may decrease the likelihood of coughing, which can induce bronchospasm. Muscle relaxants that do not release histamine, such as cisatracurium and rocuronium, can be used to facilitate endotracheal intubation. Prior to intubation, lidocaine may be administered (see section C.5).
Avoidance of intubation altogether is another approach. A supraglottic airway provides a unique opportunity for the clinician to control the airway without having to introduce a foreign body into the trachea. Kim and Bishop demonstrated a reversible increase in airway resistance in intubated patients under isoflurane anesthesia and showed that this increase was not present with supraglottic airway use. Therefore, it may be an ideal airway tool in the patient with asthma not at risk for reflux and aspiration.
Laparoscopic surgeries using a supraglottic airway have been reported by multiple centers for both gynecologic surgeries and cholecystectomies. Insufflation of the abdomen and manipulation of the bowel places these patients at increased aspiration risk. However, the use of a specialized supraglottic airway such as LMA ProSeal can mitigate these effects by allowing for placement of an orogastric tube for drainage of the stomach and a larger cuff size that reduces both the risk for gastric inflation and aspiration of refluxed gastric contents.
Reference(s):
- Barash PG, Cullen BF, Stoelting RK, et al, eds. Clinical Anesthesia. 8th ed. Philadelphia, PA: Wolters Kluwer; 2017:775-776.
- Hines RL, Marschall KE, eds. Stoelting’s Anesthesia and Co-existing Disease. 7th ed. Philadelphia, PA: Elsevier; 2018:20-22.
- Kim ES, Bishop MJ. Endotracheal intubation, but not laryngeal mask airway insertion, produces reversible bronchoconstriction. Anesthesiology. 1999;90:391-394.
- Maltby JR, Beriault MT, Watson NC, et al. The LMA-ProSeal is an effective alternative to tracheal intubation in laparoscopic cholecystectomy. Can J Anaesth. 2002;49:857-862.
- Woods BD, Sladen RN. Perioperative considerations for the patient with asthma and bronchospasm. Br J Anaesth. 2009;103(suppl 1):i57-i65.