Swallowing ability and intra-oral water-retaining ability during moderate propofol sedation in healthy human volunteers: A prospective observational study.

BACKGROUND: The cough reflex or aspiration under monitored anaesthesia care might be associated with sedative-induced changes in swallowing and intra-oral water-retaining abilities. OBJECTIVES: To investigate the effects of moderate propofol sedation on swallowing and intra-oral water-retaining ability. DESIGN: Prospective observational study. SETTING: Single tertiary care centre during 2017. PARTICIPANTS: A total of 13 healthy adult volunteers. INTERVENTION: Volunteers in the supine position were asked to retain 10 ml of orally injected water for 5 min. After 5 minutes or when the water was spontaneously swallowed, the retention time and residual intra-oral water volume were measured. Subjects then voluntarily swallowed a further 10 ml of injected water and the residual water volume was measured. This whole process was repeated under sedation with propofol at effect-site concentrations of 0.5, 1.0 and 1.5 µg ml-1. MAIN OUTCOME MEASURES: The primary outcome was the estimated volume swallowed (swallowing volume); the secondary outcome was water retention time. RESULTS: Median water retention time decreased from 300 to 11 s (P < 0.001), and greater spontaneous swallowing was induced with increased propofol effect-site concentrations measuring up to 1.5 µg ml-1 (P < 0.001). The median of the estimated swallowing volumes with voluntary swallowing while awake and with all three concentrations of propofol were 9.5, 9.6, 9.6 and 9.4 ml, respectively (P = 0.805); more water remained after spontaneous swallowing than after voluntary swallowing at all concentrations. Differences in mean estimated swallowing volumes between voluntary and spontaneous swallowing were 3.4 ml (95% CI, 0.9 to 6.0, P = 0.016) for 0.5 µg ml-1, 4.1 ml (95% CI, 1.8 to 6.3, P = 0.002) for 1.0 µg ml-1 and 5.1 ml (95% CI, 3.4 to 6.8, P < 0.001) for 1.5 µg ml-1. CONCLUSIONS: Moderate propofol sedation decreases water-retaining ability but has no effect on voluntary swallowing. Ensuring that patients can respond under sedation may effectively prevent the unexpected cough reflex and aspiration by enabling occasional voluntary swallowing. TRIAL REGISTRATION: UMIN Clinical Trials Registry identifier: UMIN000027517.

Dexmedetomidine and Midazolam Sedation Reduces Unexpected Patient Movement During Dental Surgery Compared With Propofol and Midazolam Sedation.

PURPOSE: Owing to its unpredictability, unexpected patient movement is one of the most important problems during surgery while under monitored anesthesia care with sedation. The purpose of this study was to compare unexpected patient movement during dental surgery while under dexmedetomidine and propofol sedation. MATERIALS AND METHODS: The authors designed and implemented a prospective randomized controlled trial. Patients undergoing dental surgery requiring intravenous sedation were randomly assigned to dexmedetomidine and midazolam (dexmedetomidine group) or propofol and midazolam (propofol group) sedation. In each group, midazolam 0.02 mg/kg was administered in conjunction with continuous administration of dexmedetomidine or propofol to maintain a bispectral index value of 70 to 80. Unexpected patient movement interfering with the procedure was defined as acceptable, defined as no body movement or only 1 controllable movement, or unacceptable, defined as at least 2 controllable movements or any uncontrollable movement. The primary outcome was unexpected patient movement, and the secondary outcome was defined as snoring and cough reflex. Other variables included demographic and procedural characteristics. Continuous or ordinal variables were analyzed using the Student t test or Mann-Whitney test. Dichotomous or categorical variables were analyzed using the χ2 test or Fisher exact test. A P value less than.05 was considered statistically significant. RESULTS: Eighty-eight patients were enrolled in the study (dexmedetomidine group, n = 44; propofol group, n = 44). There were no relevant differences between groups for demographics and baseline variables. Intraoperative unacceptable patient movement occurred more commonly in the propofol group (n = 13; 30%) than in the dexmedetomidine group (n = 4; 9%; P = .015). Intraoperative snoring occurred more commonly in the dexmedetomidine than in the propofol group (P = .045). Incidence and number of cough reflexes were comparable between groups. CONCLUSION: Dexmedetomidine and midazolam sedation decreases unexpected patient movement during dental surgery compared with propofol and midazolam sedation.

Clinical Use of Preformed Microcuff® Pediatric Endotracheal Tubes in Japan.

Preformed cuffed oral endotracheal tubes are widely used to intubate children undergoing oral surgery. To evaluate the efficacy and safety of oral Ring-Adair-Elwyn (RAE) Microcuff® pediatric endotracheal tubes, we retrospectively investigated the endotracheal tube exchange rate and associated complications in Japanese children younger than 2 years of age undergoing cheiloplasty or palatoplasty. The exchange rate was 3.5%, and although unplanned extubations occurred in 2 patients, no severe complications were observed. Our results suggest that oral RAE Microcuff® tubes are effective and safe for intubating Japanese children younger than 2 years of age, with a low tube exchange rate and minor complications.

Mandibular advancement impairs swallowing ability more than head extension but less than mouth opening in the supine position.

Mandibular advancement in the supine position may influence swallowing during dental treatment under intravenous sedation. This study investigated the influence of mandibular advancement in the supine position on swallowing ability, compared with head extension and mouth opening. The water swallowing test was performed in 13 healthy, awake, supine, adult subjects under four head and mandibular positions. An electromyogram of the suprahyoid muscles was recorded; the duration and peak amplitude were examined. A greater volume of water remained in the mouth during mouth opening and mandibular advancement relative to the neutral position; the volume in the mandibular advancement position was larger and smaller than that in the head extension position and during mouth opening, respectively. The duration of the electromyogram in the head extension position was longer than that in the mandibular advancement position, without differences in the amplitude. Thus, swallowing ability in the supine position was more impaired with mandibular advancement, relative to neutral and head extension positions, but less than that observed with mouth opening. Although unconfirmed by electromyogram, our findings suggest that head extension might improve airway patency by reducing the impairment of swallowing ability compared with mandibular advancement.