Noninvasive experimental bladder pain assessment in painful bladder syndrome.

OBJECTIVE: To compare bladder sensitivity between patients with pelvic pain and patients who were pain free, undergoing noninvasive, controlled bladder distension via diuresis. We also sought to measure potential mechanisms underlying bladder sensitivity. DESIGN: Prospective observational study. SETTING: Community teaching hospital. POPULATION: Reproductive-age women with non-bladder chronic pelvic pain (CPP, n = 23), painful bladder syndrome (PBS, n = 23), and pelvic pain-free controls (n = 42) METHODS: Participants were compared on cystometric capacity, pelvic floor pressure-pain thresholds (PPTs), pelvic muscle function, O'Leary-Sant bladder questionnaire, and psychosocial instruments using Wilcoxon rank-sum tests. Multivariate regression was used to identify factors underlying bladder pain phenotypes. MAIN OUTCOME MEASURES: Pelvic floor pain thresholds; self-reported bladder distension pain. RESULTS: Participants with PBS exhibited higher bladder distension pain than those with CPP, with both groups reporting higher pain levels than controls (P < 0.05). No significant associations were found between bladder distension pain and pelvic muscle structure or pain sensitivity measures; however, bladder distension pain positively correlates with both vaginal PPTs adjacent to the bladder (r = 0.46) and pain with transvaginal bladder palpation (r = 0.56). Pain at maximal distension was less influenced by somatic sensitivity than bladder symptoms (r = 0.35 versus r = 0.59; P < 0.05). Multivariate regression identified three independent components of bladder symptoms in PBS: bladder distension pain, bladder sensation, and somatic symptoms. CONCLUSIONS: Diuresis-induced bladder pain differentiates CPP from PBS. Experimental bladder pain is not predicted by pelvic floor sensitivity. Compared with patient-reported outcomes it appears less influenced by psychological factors. Further study is needed to determine whether screening for experimental bladder pain sensitivity could predict future risk of PBS. TWEETABLE ABSTRACT: Controlled, water ingestion-provoked bladder pain can objectively identify visceral pain sensitivity.

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.

Prenatal plasma matrix metalloproteinase-9 levels to predict spontaneous preterm birth.

OBJECTIVE: Matrix metalloproteinase-9, a zinc-dependent proteinase, may be important in initiating labor or rupture of membranes. We determined plasma levels of this enzyme in nonpregnant and pregnant women and evaluated whether they predict spontaneous preterm delivery. METHODS: A sandwich enzyme-linked immunosorbent assay (ELISA) was used to measure matrix metalloproteinase-9 levels in plasma samples from 25 nonpregnant women (mean age 39+/-9 years) and in stored plasma samples obtained during a randomized trial of zinc supplementation in pregnancy. Women were selected who delivered following spontaneous labor or premature rupture of membranes at 24-32 weeks (n = 20), 33-36 weeks (n = 29), and greater than 37 weeks (n = 30). Plasma samples were obtained sequentially at 19, 26, 31, and 36 weeks if undelivered and at presentation for delivery. RESULTS: Plasma matrix metalloproteinase-9 levels for non-pregnant women averaged 18.6+/-11.2 (mean +/- standard deviation) ng/mL. Prenatal values averaged 298+/-227 ng/mL from 19 weeks until 36 weeks (not including presentation for delivery) and did not change significantly as the gestational age increased, regardless of whether women ultimately delivered at 24-32, 33-36, or after 37 weeks. Values obtained prior to, but within 1 week of, presentation for delivery (n = 7, 281+/-103 ng/mL) were not significantly different than those obtained earlier in pregnancy (n = 71, 309+/-307 ng/mL, [P = .60]). Plasma matrix metalloproteinase-9 levels for women in spontaneous labor were similar regardless of gestational age and were increased three-fold (852+/-301 ng/mL) compared with those drawn at each prenatal visit (for example, 26 week values = 285+/-144 ng/mL [P < .001]). CONCLUSION: Plasma matrix metalloproteinase-9 levels remain unchanged throughout pregnancy until the onset of spontaneous labor when there is a three-fold increase. Plasma matrix metalloproteinase-9 levels obtained prior to presentation for delivery do not appear to predict spontaneous preterm birth.