Estimation of effective dose of propofol mono-sedation for successful insertion of upper gastrointestinal endoscope in healthy, non-obese Chinese adults.

WHAT IS KNOWN AND OBJECTIVE: Propofol is effective in sedation for upper gastrointestinal (UGI) endoscopy. However, the optimum dose is ill-defined. This study aimed to estimate the effective dose of propofol mono-sedation for successful endoscope insertion in healthy, non-obese Chinese adults undergoing single UGI endoscopy. METHODS: Twenty-six adult patients undergoing elective single UGI endoscopy were enrolled in this study. A modified Dixon's up-and-down method was utilized to assess the effective dose of propofol for successful endoscope insertion. The initial dose of propofol administered, 1.6 mg/kg, was adjusted with 0.1 mg/kg as a step size. The patient's responses to endoscope insertion were classified as either 'movement' or 'no movement'. When patient's responses were changed from 'movement' to 'no movement' or from 'no movement' to 'movement', a crossover was defined. After eight crossovers had been obtained, patient recruitment was stopped. The mean of midpoints of all crossovers obtained by the modified Dixon's up-and-down method in all 26 patients was defined as calculated median effective dose (ED50 ) of propofol for successful endoscope insertion. Furthermore, probit regression analysis was used to determine the dose of propofol where 50% (ED50 ) and 95% (ED95 ) of endoscope insertion attempts were successful. RESULTS: The calculated ED50 of propofol for successful endoscope insertion was 1.89 ± 0.12 mg/kg. The probit regression analysis showed that ED50 and ED95 of propofol for successful endoscope insertion were 1.90 mg/kg (95% CI, 1.78-2.10 mg/kg) and 2.15 mg/kg (95% CI, 2.01-3.56 mg/kg), respectively. No any patient had hypoxaemia and gag reflex during the UGI endoscopy with propofol mono-sedation. WHAT IS NEW AND CONCLUSION: In healthy, non-obese Chinese adults, propofol mono-sedation can provide excellent conditions of UGI endoscopy and the estimated ED50 of propofol for successful endoscope insertion is 1.89 ± 0.12 mg/kg.

A ternary hybrid CdS/Pt-TiO2 nanotube structure for photoelectrocatalytic bactericidal effects on Escherichia coli.

A ternary hybrid CdS/Pt-TiO(2) nanotube (NT) photoelectrode was developed by dipping and deposition technique as well as successive ionic layer adsorption and reaction (SILAR). Small Pt nanoparticles (NPs) and CdS NPs were effectively deposited on both the inside and outside of the TiO(2) NTs. The as-prepared hybrid shows enhanced photon absorption and photocurrent generation efficiency. Higher bactericidal effect to Escherichia coli was observed on the ternary hybrid CdS/Pt-TiO(2) NTs as compared with Pt-TiO(2) NTs or pure TiO(2) NTs.