Measuring intrabladder pressure with the head of the bed elevated 30°: evidence to support a change in practice.

ABSTRACT

BACKGROUND: A 30° head-of-bed elevation is recommended for most critically ill patients. Measuring intrabladder pressure with the patient in this position is controversial. OBJECTIVE: To assess the feasibility of measuring intrabladder pressure with a 30° head-of-bed elevation. METHODS: A prospective, randomized, and experimental study. Patients had intrabladder pressure measured first while positioned supine with a 30° head-of-bed elevation and 25 mL of saline instilled into the bladder and again after the patients were randomly repositioned to supine without any head-of-bed elevation (flat) or with a 30° head-of-bed elevation while supine or in right lateral or left lateral position with either 25, 50, or 200 mL of saline instilled into the patient's bladder. RESULTS: Intrabladder pressures measured with the patient in all 3 head-of-bed elevated positions were higher than pressures measured with patients supine and flat after instillation of 25 mL of saline into the bladder, but intrabladder pressure did not differ between the 30° head-of-bed elevated positions and the supine and flat positions when 50 or 200 mL of saline was instilled into the bladder. Two-way analysis of variance showed a significant interaction between volume of saline instilled (P = .05), patient's position (P = .007), and bladder instill volume and position interaction (P = .004). CONCLUSION: It is feasible to measure intrabladder pressure with a 30° head-of-bed elevation, and that position could be an alternative to supine positioning of patients for measurement of intrabladder pressure.