title: Intra-abdominal hypertension in the critically ill: interrater reliability of bladder pressure measurement.
abstract: OBJECTIVE
  Intra-abdominal hypertension is frequently underdiagnosed and defined by intra-abdominal pressure (IAP) 12 mm Hg or higher. Increasing IAP may compromise organ viability and culminate in abdominal compartment syndrome. Bladder pressure measurement is a surrogate for IAP, but measurement properties are unknown in the intensive care unit. Our primary objective was to assess the agreement of bladder pressure measurements in critically ill patients.
  
  
  METHODS
  We conducted an observational study examining the correlation of measurement variability of bladder pressure. Four raters (2 nurses and 2 physicians) measured IAP. Patient's age, Acute Physiology and Chronic Health Evaluation II, body mass index, mechanical ventilation parameters, and demographics were collected.
  
  
  RESULTS
  Fifty-one patients had bladder pressures measured in quadruplicate, producing 204 measurements. Among 51 patients, the mean age was 61.9 years, Acute Physiology and Chronic Health Evaluation II was 23.8, and body mass index was 27.8 kg/m2. The average bladder pressure was 12.4 (SD, ±6.2) mm Hg. The interrater agreement by intraclass correlation coefficient was 0.745 (95% confidence interval [CI], 0.637-0.825), 0.804 (95% CI, 0.684-0.882), and 0.626 (95% CI, 0.428-0.767) among all raters, physicians, and nurses, respectively.
  
  
  CONCLUSIONS
  Agreement on bladder pressure was high among 4 clinicians and were not significantly different between physicians and nurses. Given that medical/surgical treatments are considered on bladder pressure values, understanding their reliability is essential to monitor critically ill patients.
authors.affiliation: Department of Medicine, McMaster University, Hamilton, ON L8S 4L8, Canada. Electronic address: christina.katsios@medportal.ca.
authors.forename: Christina
authors.initials: C
authors.lastname: Katsios
authors.forename: Chenglin
authors.initials: C
authors.lastname: Ye
authors.forename: Neala
authors.initials: N
authors.lastname: Hoad
authors.forename: Thomas
authors.initials: T
authors.lastname: Piraino
authors.forename: Mark
authors.initials: M
authors.lastname: Soth
authors.forename: Deborah
authors.initials: D
authors.lastname: Cook
mesh_terms: D018806:APACHE; D015992:Body Mass Index; D016638:Critical Illness; D003710:Demography; D005260:Female; D006801:Humans; D059325:Intra-Abdominal Hypertension / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012121:Respiration, Artificial; D012307:Risk Factors; D001743:Urinary Bladder / Q000503:physiopathology*
keywords: Intensive care unit; Inter-observer variability; Intra-abdominal hypertension