Initial loading of dexmedetomidine and continuous propofol sedation for prevention of delayed recovery: A randomized controlled trial.

BACKGROUND: Sedation with continuous dexmedetomidine and bolus midazolam administration provides a lower incidence of unacceptable patient movement during procedures but requires a longer recovery time. The authors aimed to compare recovery time and unacceptable patient movement during sedation with initial loading of dexmedetomidine followed by continuous propofol infusion with those during sedation with continuous dexmedetomidine and bolus midazolam administration. METHODS: In this prospective randomized controlled trial, 54 patients undergoing dental surgery and requiring intravenous sedation were assigned to either the dexmedetomidine and propofol group (n = 27, dexmedetomidine administered at 6 µg/kg/h for 5 minutes, followed by continuous propofol infusion using a target-controlled infusion) or the dexmedetomidine and midazolam group (n = 27, dexmedetomidine administered at 0.2-0.7 µg/kg/h continuously after the same initial loading dose with bolus midazolam). A bispectral index of 70 through 80 was maintained during the procedure. Patient movement that interfered with the procedure and time from the end of sedation to achieving a negative Romberg sign were assessed. RESULTS: Times from the end of sedation to achieving a negative Romberg sign in the dexmedetomidine and propofol group (median, 14 minutes [interquartile range, 12-15 minutes]) were significantly shorter (P < .001) than in the dexmedetomidine and midazolam group (median, 22 minutes [interquartile range, 17.5-30.5 minutes]). The incidence of unacceptable patient movement was comparable between groups (n = 3 in the dexmedetomidine and propofol group, n = 4 in the dexmedetomidine and midazolam group; P = .999). CONCLUSIONS: Sedation with a single loading dose of dexmedetomidine followed by continuous propofol infusion can prevent delayed recovery without increasing unacceptable patient movement. PRACTICAL IMPLICATIONS: The combination of dexmedetomidine and propofol may provide high-quality sedation for ambulatory dental practice. This clinical trial was registered in the University Hospital Medical Information Network Clinical Trials Registry. The registration number is UMIN000039668.

Isoflurane induces Art2-Rsp5-dependent endocytosis of Bap2 in yeast.

Although general anesthesia is indispensable during modern surgical procedures, the mechanism by which inhalation anesthetics act on the synaptic membrane at the molecular and cellular level is largely unknown. In this study, we used yeast cells to examine the effect of isoflurane, an inhalation anesthetic, on membrane proteins. Bap2, an amino acid transporter localized on the plasma membrane, was endocytosed when yeast cells were treated with isoflurane. Depletion of RSP5, an E3 ligase, prevented this endocytosis and Bap2 was ubiquitinated in response to isoflurane, indicating an ubiquitin-dependent process. Screening all the Rsp5 binding adaptors showed that Art2 plays a central role in this process. These results suggest that isoflurane affects Bap2 via an Art2-Rsp5-dependent ubiquitination system.

Anaphylaxis with delayed appearance of skin manifestations during general anesthesia: two case reports.

BACKGROUND: Anaphylaxis is difficult to diagnose in the absence of skin or mucosal signs and symptoms. We report two cases of anaphylaxis under general anesthesia, in which the initial presentation was in the form of respiratory signs, followed by skin manifestations 10-15 min later. Diagnosis of anaphylaxis was delayed because skin symptoms were absent early on in the presentation. CASE PRESENTATION: In the first case, a 23-year-old male patient with jaw deformity was scheduled to undergo maxillary alveolar osteotomy. After intubation, auscultation indicated a sudden decrease in breath sounds, together with severe hypotension. Approximately 10 min later, flushing of the skin and urticaria on the thigh appeared and spread widely throughout the body. In the second case, a 21-year-old female patient with jaw deformity was scheduled to undergo maxillomandibular osteotomy. Twenty minutes after the start of dextran infusion, her lungs suddenly became difficult to ventilate, and oxygen saturation decreased to 90%. Approximately 15 min later, flushing of the skin and urticaria were observed. CONCLUSION: In both cases, there was a time lag between the appearance of respiratory and skin symptoms, which resulted in a delay in the diagnosis, and hence, treatment of anaphylaxis. Our experience highlights the fact that it is difficult to diagnose anaphylaxis under general anesthesia.