Chronic exercise-induced compartment pressure elevation measured with a miniaturized fluid pressure monitor

Abstract

Increased pressure within an osteofascial compartment may produce a compartment syndrome, one of the principal causes of circulatory compromise in acute traumatic and chronic exercise-induced elevated com partment pressure. Acute and chronic diagnostic quan titation of compartment pressures are a valuable ad junct to clinical diagnosis, particularly when used to evaluate the athlete with exercise-induced pain. This study evaluated a prototype hand-held, digital, fluid pressure monitor used for the measurement of com partment pressure in the exercising athlete. A laboratory water and mercury manometer study, in which 50 paired, single-blind measurements were taken, revealed that the digital monitor was accurate to ±0.8 mm Hg (SD) of actual pressure with no individ ual reading more than 1 mm Hg from the actual pres sure when compared directly with a mercury and a water column. Laboratory study of bovine muscle placed within a pressure chamber revealed that the digital monitor, when assembled in the same manner as used for clinical measurement, was accurate to ±0.9 mm Hg. The needle manometer technique was also found to be accurate to ±3 mm Hg from actual pressure. Twenty-one paired measurements of the anterola teral and posterior compartments of the hindlimbs of eight anesthetized New Zealand White rabbits by both the needle manometer and digital monitor methods by two examiners demonstrated the digital monitor to be reproducible to ±1.0 mm Hg [Coefficient of variation (CV) <7%] and needle manometer method to ±3.4 mm Hg (CV <16%) with r = 0.94. The time taken for digital monitor assembly and actual measurement was four times faster (2.3 minutes versus 8.4 minutes) than that for the needle manometer method when all materials were readily available to physicians skilled in the use of both compartment pressure measurement techniques. Paired and duplicate measurements were made using both the standard needle manometer technique and the new digital monitor on 58 patients with suspected compartment syndrome. Thirty-nine patients suffered from an acute traumatic etiology, nine athletes suffered from exercise-induced pain, and three of a vascular etiology. In patient studies, replicate digital monitor measurements were accurate to ±1.4 mm Hg (CV <6%) and to ±2.8 mm Hg (CV <12%) by the needle manometer technique, with r = 0.88. All patients toler ated the procedure well, even with the device strapped to the leg for exercise monitoring. Nine athletes suspected of suffering from chronic compartment syndrome were studied constantly during the course of an 8 minute provocative exercise test which reproduced symptoms in each. Compartment pressures were found to be elevated at rest in eight of nine athletes and to be dangerously elevated in four of the nine patients studied, according to criteria defined by Heppenstall. The criteria of Heppenstall and of Mu barak were applied as an indication for surgical fasciot omy in all athletes studied. The hand-held monitor was found to be more accurate, versatile, convenient, and less time-consuming to use than the standard needle manometer method of compartment pressure measure ment. The new digital device is uniquely suited for easy, dependable measurement of chronic exercise-induced compartment pressure elevation in the office setting and represents a significant advance in the diagnostic management of acute and exercise-induced compart ment syndrome.