Limiting Emergence Phenomena After General Anesthesia With Combined LMA and ETT Airway Management Technique

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.

Inclusion Criteria:

- ASA 1-3

- Patients undergoing elective laparoscopic surgery

Exclusion Criteria:

- Individuals who cannot provide consent

- Individuals who would require translation services to provide consent

- Prisoners

- Parturients

- Non-fasted patients (as per HMC Anesthesiology Department NPO policy)

- Patients felt to be high risk for gastric reflux and pulmonary aspiration (those with
gastroparesis, symptomatic GERD, etc.: at the discretion of primary anesthesia team)
Those patients with anticipated difficult airway requiring maintenance of spontaneous
ventilation (awake intubation)