RELIABILITY OF INTRABLADDER PRESSURE MEASUREMENT IN INTENSIVE CARE

Background The reliability of intrabladder pressure measurements obtained in nonsupine patients is unknown. Objectives To investigate the reliability of measurements of intrabladder pressure obtained with 30 head-of-bed elevation. Methods With patients supine, 30 head-of-bed elevation, and instillation of 0 and 25 mL physiological saline, intrabladder pressure was measured in 10 patients: twice by one nurse to assess intraobserver reliability and once by a different nurse to assess interobserver reliability. Data were analyzed by using paired t tests, Pearson correlation, and Bland-Altman analysis. Results For intraobserver reliability, measurements obtained with no instillation (mean difference, -1.8; 95% confidence interval [CI], -4.9 to 1.3; P=.22) and with instillation of 25 mL (mean difference, -0.6; 95% CI, -1.8 to 0.6; P=.28) did not differ significantly. Pearson r values were 0.74 and 0.81, respectively. Estimated Bland-Altman bias and limits of agreements were -1.8 and -10.3 to 6.7 mm Hg and -0.6 and -3.82 to 2.62 mm Hg, respectively. For interobserver reliability, measurements obtained with no instillation (mean difference, 1.0; 95% CI, -2.2 to 4.2; P=.49) and with instillation of 25 mL (mean difference, -0.7; 95% CI, -2.45 to 1.05; P=.39) did not differ significantly. Pearson r values were 0.78 and 0.82, respectively. Estimated Bland-Altman bias and limits of agreement were 1.0 and -7.76 to 9.76 mm Hg and -0.7 and -5.5 to 4.0 mm Hg, respectively. Conclusions Reliability of intrabladder pressure measurements obtained with 30 head-of-bed elevation is strong. (American Journal of Critical Care. 2010; 19: e29-e40).