LAUSR

Dear Editor, Emergence from anaesthesia and deep sedation is the transition from unconsciousness to the return of awareness and airway reflexes. The chief patterns of unsafe recovery include sudden unpredictable emergence or delayed return of airway tone and reflex with risk of airway obstruction.1 Agitation includes straining, sitting up, screaming or shouting. Even with supraglottic airway (SGA) use, coughing and expulsion of airway secretions can occur in 14–19% of patients.2 Emergence is more predictable when guided by surrogate measures of anaesthetic depth evaluated by processed cortical electroencephalography (EEG) analysis, such as the bispectral index monitoring system (Covidien-Medtronic, Boulder, US) or SedLine (Masimo Corp, Irvine, US);3 or volatile anaesthetic concentration measurements of end-expiratory gas analysis. However, these require specialised equipment that is largely limited to the operating theatre (OT) environment. These technologies are less consistently employed when patients are sedated or anaesthetised in resource-limited settings, or in locations outside the OT and in postanaesthesia care units (PACU) where patients recover with airway devices in situ until they can maintain their airway patency unassisted. A randomised controlled trial was conducted to evaluate the use of a novel technique utilising pressure on the tragus—a fleshy prominence in front of the ear canal—to guide emergence. The tragus pressure technique (Fig. 1) encompasses the application of 3–5 seconds of pressure at 10–30 newtons on the tragus, calibrated by staff pre-trained with using weighing scales to apply optimal non-nociceptive pressure on the tragus. Tragus pressure application is postulated to stimulate neuro-humoral outflow, thalamo-cortical projections and the reticular activating system.4-6 This might produce arousal to wakefulness without resulting in sudden emergence, thus guiding and smoothening the process of emergence, removal of airway devices, and safe recovery. The application of tragus (TG) pressure (acupuncture points TG1 and TG2) with counterpressure at the intertragal notch and antitragus (AT) (acupuncture points AT1, AT2 and AT3) shown in Fig. 1 is known to stimulate airway and autonomic responses.7,8 This pressure application might have triggers on the projections to the solitary nucleus, which is in turn part of the complex neural circuitry that contributes to arousal to hypercarbia.7 We evaluated the facilitation of emergence from anaesthesia and deep sedation through the application of tragus pressure in this randomised controlled study. Ann Acad Med Singap 2022;51:661-3 https://doi.org/10.47102/annals-acadmedsg.2022152