Comparison of 2 available methods with Bland-Altman analysis for measuring intracompartmental pressure.

ABSTRACT

BACKGROUND: Acute compartment syndrome (ACS) is the result of increased intracompartmental pressure (ICP), and to avoid a delay in diagnosis requires ICP measurement. This study was designed to compare 2 available methods with Bland-Altman analysis for measuring ICP in experimental animal models, healthy volunteers, and patients with suspected ACS to evaluate their agreement and interchangeability. METHODS: In 20 New Zealand White rabbits, we inflated a tourniquet to stop arterial blood flow to establish ACS rabbit models, of which ICP was measured and recorded by the Whitesides apparatus and the invasive arterial blood pressure monitor system (IABPMS) before and after modeling. The same 2 measurements were applied to the tibialis anterior compartment's ICP of 30 healthy volunteers. The experimental data were analyzed using the Bland-Altman method. Once it was considered to be a substitute for the Whitesides apparatus based on statistical analysis, we used IABPMS to measure the ICP of the patients suspected of having ACS to estimate its clinical prospect. RESULTS: The rabbit models' ICP estimated by the Whitesides apparatus and IABPMS were 9.60±2.74 and 9.55±2.33 mm Hg, with an increase to 30.20±4.44 and 30.05±4.58 mm Hg after modeling, respectively. The limits of agreement for the ICP were -2.01/2.11 and -2.41/2.71 mm Hg before and after model establishment. The healthy volunteers' ICP were 10.92±6.06 and 10.85±5.87 mm Hg; the limits of agreement for the ICP were -2.53/2.66 mm Hg. With IABPMS to continuously monitor the ICP increasing (40.45±10.42 vs 13.82±4.94 mm Hg) and ΔP (34.54±11.77 mm Hg) to guide the diagnosis of ACS, 5 of 11 patients underwent the emergency fasciotomy for decompression. CONCLUSION: The invasive pressure monitoring via IABPMS can be used as an alternative to the Whitesides method, thanks to the sufficient agreement between the 2 methods in ICP measurement, and also for its advantages recommended as a novel diagnostic approach to ACS in experimental and clinical applications.