Dilute versus concentrated vasopressin administration during laparoscopic myomectomy: a randomised controlled trial.

OBJECTIVE: To determine if higher-volume, fixed-dose administration of vasopressin further reduces blood loss at the time of minimally invasive myomectomy. DESIGN: Randomised multicentre clinical trial. SETTING: Tertiary-care academic centres in the USA. POPULATION: Women undergoing conventional laparoscopic or robot-assisted laparoscopic myomectomy. METHODS: All participants received the same 10-unit (U) dose of vasopressin, but were randomly assigned to one of two groups: (i) received 200 ml of diluted vasopressin solution (20 U in 400 ml normal saline), and (ii) received 30 ml of concentrated vasopressin solution (20 U in 60 ml normal saline). MAIN OUTCOME MEASURES: The primary study outcome was estimated blood loss; the study was powered to detect a 100-ml difference. RESULTS: A total of 152 women were randomised; 76 patients in each group. Baseline demographics were similar between groups. The primary outcome of intraoperative blood loss was not significantly different, as measured by three parameters: surgeon estimate (mean estimated blood loss 178 ± 265 ml and 198 ± 232 ml, dilute and concentrated groups respectively, P = 0.65), suction canister-calculated blood loss, or change in haematocrit levels. There were no vasopressin-related adverse events. CONCLUSION: Both dilute and concentrated vasopressin solutions that use the same drug dosing demonstrate comparable safety and tolerability when administered for minimally invasive myomectomy; however, higher volume administration of vasopressin does not reduce blood loss. TWEETABLE ABSTRACT: This randomised trial failed to show benefit of high-volume dilute vasopression.

Improvement of the resolution in direct membrane integrity test by controlling solution surface tension.

Membrane-based treatment technologies have been introduced as a promising tool for the removal of water-borne pathogens. To ensure successful application of membrane processes, the integrity of the membrane system should be maintained. Related with evaluation of the membrane integrity, USEPA guidance recommends pressure-based membrane integrity (MIT). Based on the bubble point theory, the ability of detecting smallest integrity breakage during the MIT is defined as "Resolution". However, the response to remarkably small breach demands significantly high initial test pressure of the pressure decay test. In this study, the surface tension of the test liquid was controlled to improve the resolution without increasing the corresponding test pressure. Three common chemicals were chosen to control the solution surface tension. It is concluded that 0.1 M of the citric acid can decrease the initial test pressure significantly for the same pore size. Subsequently, the improvement of the resolution with controlled surface tension was confirmed by the results of pressure decay test and marker test.