Optimising the measurement of intra-bladder pressure in patients with predicted severe acute pancreatitis.

Background: Measuring intra-abdominal pressure (IAP) is important for management of patients with severe acute pancreatitis (SAP). Intra-bladder pressure (IBP) is an indirect index that reflects IAP, but measuring techniques vary. We sought to optimise IBP measuring techniques in predicted SAP patients.

Methods: Predicted SAP patients consecutively admitted between June 2018 and January 2020 were scrutinised. Eligible patients had their IBP monitored for the first 72 h at 6-h intervals, and were then sequentially allocated into three research scenarios: (1) in the supine position along with head of bed elevation(HoBE)of 0, 15 and 30° at various points including the iliac crest the midaxillary line, pubic symphysis, and right atrium level, instilled with 25 mL normal saline (NS) at room temperature (RT); (2) NS instillation volume from 0, 10, 25, 40-50 mL at the iliac crest with HoBE15 at RT; and (3) NS instillation (25 mL) at either RT or 37 °C with HoBE15.

Results: The dynamic IBP values measured at the pubic symphysis and iliac crest were fairly similar between HoBE0 and HoBE15 (all P > 0.05), but greatly increased at HoBE30 (all P < 0.01). IBP was significantly increased with escalating instillation volumes of NS (all P < 0.01 versus 0 mL NS), while there was no significant difference between 25 mL and 10 mL (P = 0.055). IBP was similar between NS at RT and under 37 °C (P = 0.643).

Conclusion: In predicted SAP patients, measuring IBP at the iliac crest with HoBE15 after instilling 10 mL of NS seems to be appropriate for monitoring IAP.