Emergence from general anesthesia is a critical period of anesthetic management (1.
Popat, 2012). The noxious stimuli of an endotracheal tube as well as the excitement stage
of anesthesia, commonly seen prior to return of consciousness while emerging from general
anesthesia, both lead to emergence phenomena of coughing, straining, and restlessness in
addition to physiologic derangements (2. Atkinson, 1987). Physiologically, emergence from
anesthesia is associated with rising sympathetic tone (as evidenced by elevated
catecholamine levels and the resultant hemodynamic changes of increasing heart rate and
blood pressure), intracranial pressure, and intraocular pressure. Airway tone and
reflexes are also problematic as they may be depressed by the lingering pharmacologic
effects of anesthetics and analgesics leading to decreased airway obstruction or
aspiration events. Airway reflexes may also be exaggerated while traversing the
excitement stage; this can lead to undesirable consequences of coughing, breath-holding,
bucking or in extreme cases laryngospasm. A smooth emergence is preferable for all
patients but is required for those patients who would not tolerate the above physiologic
changes (e.g. severe aortic stenosis or coronary artery disease, both of which would
poorly tolerate tachycardia) or those would be at risk in terms of the procedure that was
performed (cerebral aneurysm clipping, carotid endarterectomy, thyroidectomy: procedures
in which stress fresh surgical wounds with hypertension and straining would be
undesirable).
Several airway management (3. Koga 1998, 4. Perello-Cerda 2015) and pharmacologic
strategies (5. Minogue 20014, 6. Nho 2009, 7. Guler 2005) have been employed to provide a
smooth emergence from general anesthesia. One of the most efficacious strategies is the
use of supraglottic airway devices rather than endotracheal tubes. Despite evidence
supporting the safety and efficacy of ventilation of SGAs during laparoscopic procedures
(8. Natalini 2003, 9. Belena 2012, 10. Carron 2012, 11. Bernardini 2009), many
anesthesiologists would prefer the use of an ETT to an SGA in cases in which higher
ventilation pressures may be required (obesity, steep Trendeleberg position,
pneumoperitoneum). In addition to the cases requiring high ventilation pressures, ETTs
are preferred to SGAs in those patients who are perceived to be high risk for reflux and
pulmonary aspiration of gastric contents (non-fasted, intestinal obstruction,
gastroparesis, parturients), as well as during cases that allow the anesthesiologist to
have little accessibility the airway (neurosurgical, ENT, etc).
The Bailey maneuver (managing the airway with an ETT throughout the case and then
exchanging for an LMA while deeply anesthetized (12. Nair 1995), has also been shown to
provide less stimulating emergence. Unfortunately, the Bailey maneuver is relatively
contraindicated in cases in which there is the perception that reintubation would be
difficult, as the risks of exchanging a functioning airway device for one that has not
been tested outweighs the potential benefits of a smooth emergence.
The airway management technique under investigation involves initially placing an LMA
after induction of anesthesia. Once adequate ventilation has been accomplished using the
LMA, the patient will be endotracheally intubated using a fiberoptic bronchoscope and the
in situ LMA as a conduit (13. Timmermann 2011). General anesthesia will be maintained
with sevoflurane and narcotics at the discretion of the primary anesthesiologist. The
patient will be ventilated via the endotracheal tube during the duration of the surgical
procedure and then the trachea will be extubated while the patient is at a deep plane of
anesthesia after release of the pneumoperitoneum and return to supine positioning. This
technique is a potential method for reducing the stress of emergence in patients who
would benefit from the use of an endotracheal tube intraoperatively.