New noninvasive ultrasound technique for monitoring perfusion pressure in a porcine model of acute compartment syndrome.

OBJECTIVE

Acute compartment syndrome (ACS) is the result of decreased perfusion pressure (PP), and the diagnosis frequently requires invasive monitoring. Our objective was to test a new noninvasive ultrasound device for correlating PP with measurements of fascial displacement in a controlled porcine model of ACS. We hypothesized that fascial displacement in experimental compartments with impaired PP would be significantly greater than that in control compartments with normal baseline PP.

METHODS

ACS was generated in right anterior compartments of 7 anesthetized pigs, and contralateral compartments served as normal controls. Intramuscular pressure in all compartments was monitored by slit catheters, whereas intramuscular pressure in experimental compartments was elevated in 10 mm Hg increments by infusing 0.045% albumin in saline. A noninvasive ultrasound device continuously recorded fascial displacement corresponding to arterial pressure pulses in all compartments. Mean fascial displacement amplitude was grouped by PP and analyzed using 2-way repeated measures analysis of variance and contrast analysis.

RESULTS

As PP ranged from 80 to -40 mm Hg, the change in fascial displacement of the infused compartments was significantly greater than that in the control compartments (analysis of variance, P = 0.03). At each PP increment between 40 and -20 mm Hg, fascial displacement in the infused compartments was significantly greater than that in the control compartments (contrast analysis, P < 0.014).

CONCLUSIONS

Fascial displacement is significantly greater in muscle compartments with decreased PP. Furthermore, changes in PP are associated with changes in fascial displacement over a clinically relevant range of PP, making this noninvasive technique potentially useful for monitoring in ACS.