A Pilot Evaluation of a Capacitance-Based Automatic Urinometer in a Pediatric Intensive Care Setting

OBJECTIVES: To compare a modified capacitance-based automatic urinometer to a manual urinometer, with regard to precision of measurement and to evaluate the staff's opinion regarding the automatic urinometer. DESIGN: Prospective observational cohort study. SETTING: PICU at Astrid Lindgren's Children Hospital in Solna, Sweden. PATIENTS: Twelve children weighing up to 10 kg with an indwelling urinary catheter in place before enrollment. INTERVENTIONS: Measurement of hourly diuresis using either an automatic urinometer or manual urinometer. MEASUREMENTS AND MAIN RESULTS: Hourly diuresis was measured with an automatic urinometer (n = 127; Sippi; Observe Medical Nordic AB, Gothenburg, Sweden) or an manual urinometer (n = 83; Unometer Safeti Plus; Convatec, Lejre, Denmark) and thereafter validated with a measuring cylinder. The absolute mean bias was -1.1 mL for the automatic urinometer (CI, -0.6 to -1.5) and -0.6 mL (CI, ± 0.0 to -1.2) for the manual urinometer (p = 0.21). The SDs were 2.6 and 2.8 mL, respectively. User evaluation comparing the automatic urinometer with the manual urinometer concerning the ease of use was made with a questionnaire (n = 18). The majority of staff preferred the automatic urinometer to the manual urinometer in terms of ease of use, learning, and handling. CONCLUSIONS: The two urinometers were comparable in performance for children weighing up to 10 kg. Taking into account the overwhelming staff satisfaction with the automatic urinometer and benefits in less well-staffed wards as well as lack of temporal deviation, the modified automatic urinometer may be considered for clinical use in the PICU.