Commentary: Inhalational Induction Without Vascular Access Should Be Rare in OMS

During a presentation on Complications and Management in Anesthesia at the 106th American Association of Oral and Maxillofacial Surgeons (AAOMS) Annual Meeting, a case was presented involving a 12-year-old patient undergoing dental extractions under deep sedation/general anesthesia with an open airway technique in an oral and maxillofacial surgery (OMS) office.¹ The presenter described performing a sevoflurane inhalational induction without intravenous (IV) access, during which the patient had excessive upper airway secretions that led to laryngospasm and hypoxemia. The presenter described the management challenges to include the choice to deepen or lighten the anesthetic depth via inhaled anesthetic, the need to continue airway and ventilatory support, and the multiple attempts to gain vascular access for emergent medication delivery. The presenter described being unsuccessful in establishing IV access, but luckily, the laryngospasm resolved before the resulting hypoxemia reached critical levels. The presenter correctly identified in his discussion that safety in the OMS office requires up-to-date medical knowledge, thorough preanesthetic evaluations, careful case selection, use of memory aids, and regular emergency simulation with full staff but failed to acknowledge the unnecessary risk incurred by routinely performing inhalational inductions without prior establishment of vascular access.

It is tempting for an oral and maxillofacial surgeon to want to provide a needle-free memory to patients, particularly for short cases. The current author acknowledges that inhalational induction with or without subsequent placement of an IV is commonly practiced in pediatric anesthesia. However, the setting of a pediatric operating room has additional skilled team members already in the room or less than a minute away, which obviates the need for a single provider to manage the airway and establish vascular access in an emergency.

Inhalational inductions have a substantial incidence of challenges that arise in typical practice. In a prospective trial of 80 subjects undergoing inhalational inductions, Kangalkar et al. observed coughing (10%), salivation (5%), and patient movement (25%) in the sevoflurane group of 40 subjects. By comparison, the halothane group demonstrated an incidence of coughing, salivation, and movement of 20%, 2%, and 12.5%, respectively.² Although laryngospasm was not observed in that study, Morimoto et al. have reported a 12% incidence of coughing and a 7% incidence of laryngospasm in a prospective series of 43 children receiving sevoflurane inductions. The halothane group of 35 children in that study had a 14% incidence of coughing and 6% incidence of laryngospasm.³ The current author supports the position that these rates of coughing, salivation, patient movement, and laryngospasm are too high to routinely accept the risk of induction without prior vascular access for elective anesthetics in the OMS model.

Safety within the OMS model has been well documented in the AAOMS White Paper - Office-Based Anesthesia Provided by the Oral and Maxillofacial Surgeon.⁴ The OMS anesthesia team as defined by AAOMS includes the following: (1) a highly trained oral and maxillofacial surgeon; (2) a staff member with the dedicated responsibility of monitoring the patient; and (3) a surgical assistant. Along with the requisite monitoring systems, drugs, and equipment, the team model works best when combined with rigorous training and by ensuring risk mitigation is included throughout the process. We train with our staff and rehearse mock drills so that our team can provide needed support during emergencies; however, being able to execute key aspects of an emergency response (eg, ventilating/intubating a patient, obtaining IV access) falls on the oral and maxillofacial surgeon. Thus, the model is safest when we reduce the likelihood of needing to simultaneously manage acute airway compromise and establish vascular access.

Apprehension and fear around IV-line placement have been well described.⁵ In addition to the technical skill required to quickly and accurately establish IV access with minimal discomfort, the oral and maxillofacial surgeon must use their behavioral management skills to develop rapport with patients such that they can distract or guide the patient throughout the process. Pharmacologic aids such as oral midazolam or clonidine or inhaled nitrous oxide may be used for anxiolysis, and topical anesthesia via ethyl chloride or subcutaneous lidocaine can further aid in pain reduction at the venipuncture site. Additionally, giving clear preanesthetic instructions to parents may aid them in preparing their children for venipuncture.⁵

Some patients may be so fearful that they cannot be managed in any of the above ways. In these rare cases where IV access cannot be established prior to induction, the oral and maxillofacial surgeon should confirm that the patient has favorable IV access points and favorable airway anatomy prior to performing a mask induction in the office. Mask induction with sevoflurane should then be continued for at least 2 minutes after loss of eyelash reflex before attempting to establish vascular access,^6,7 lessening the likelihood of a reaction to venipuncture and a simultaneous acute airway event. Although intramuscular ketamine has also been described, the current author does not recommend this technique due to the higher rates of emesis and emergence delay or agitation than with IV administration as well as increased rates of hypersalivation and hypoxemia described in the literature as high as 10.9% and 8.3%, respectively.⁸ Lastly, the OMS should always consider whether the patient is too high-risk for the office-based environment and would be better managed in a hospital or surgery center.