Measurement of Intracompartmental Pressure with Use of a New Catheter System
August 1, 1999 3 minutes read
Measurement of Intracompartmental Pressure with Use of a New Electronic Transducer-Tipped Catheter System
Abstract & Commentary
Synopsis: This new electronic transducer-tipped catheter system accurately measures intramuscular pressure. It is an advanced methodology that is easy to use and reliable.
Source: Willy C, et al. Measurement of intracompartmental pressure with use of a new electronic transducer-tipped catheter system. J Bone Joint Surg Am 1999;81:158-168.
In this article, willy and colleagues describe a new type of device to measure intracompartmental pressures. Because of its unique design as an electronic transducer-tipped catheter, it avoids some of the common problems associated with the currently available intracompartmental pressure-measuring devices. Hydrostatic pressure artifacts and dependency upon the position of the limb and the height of the pressure transducer to achieve accurate readings have created problems in the past. This new device is only 1 mm in diameter and can be easily inserted into any muscular compartment. The operation is based upon a piezoresistive principle in which a semiconductor in the tip of the device changes its electrical resistance as a function of applied pressure. This study was designed to evaluate the accuracy, safety, and clinical usefulness of the device.
Basic laboratory tests were performed measuring the reproducibility of its measurements in a column of water. Then, in 20 healthy, normal people, pressures in the anterior compartment of the leg were measured using the device. In four of these volunteers, external pressure was then applied to the anterior compartment using a pneumatic antishock trouser-type device. In one volunteer, the effect of injection of normal saline into the anterior compartment was measured and in one other volunteer, four 10-minute periods of exercise on a treadmill were performed while intracompartmental pressure was being measured. Finally, prospectively, 25 patients who had clinically suspected compartment syndromes were assessed with this device and compared with a standard manometric method of measuring intracompartmental pressure.
In the 20 normal volunteers, resting pressures within the compartment of 13.1 ± 8.3 mm of mercury were obtained with a range of pressure measurements from 5.4 to 22.6 mm of mercury. Externally applied pressure dramatically increased the intracompartmental pressure, as did injection of saline into the measured compartment. With exercise, contemporary measurements showed an increased peak pressure to 175 mm of mercury when the subject was walking at the rate of 8 kilometers per hour, up a 10% gradient. In the clinical series, measurement of tissue pressure led to the diagnosis of a compartment syndrome in nine patients with a tibia fracture and clearly demonstrated an exertional compartment syndrome 18 hours after vigorous exercise in one patient. Some patients were monitored for as long as 21 hours after tibial nailing and the device continued to measure accurately throughout this entire time.
Willy et al conclude that this new electronic transducer-tipped catheter system accurately measures intramuscular pressure. They found that it is easy to use, causes minimal trauma to the subjects, has extremely high responsiveness, and needs no equilibration time to achieve accurate measurements. One potential source of error can occur if the end of the device is placed directly into a tendon or even into cross-wise tensed muscle fibers. Willy et al, therefore, recommend that the probe should always be inserted parallel to the muscle fibers. They conclude that this device is an advanced methodology that is easy to use and reliable.
Comment by James D. Heckman, MD
Measurement of intracompartmental pressures remains a critical tool in the evaluation of patients who may be developing or experiencing compartment syndromes. This new device eliminates some of the "fiddle factor" associated with the manometric devices and this study demonstrates that it is easy to use and the results are reproducible. In the sports medicine arena, this particular type of catheter system, because of its ease of insertion and essentially artifact-free dynamic responses to changes in intramuscular pressures, may provide substantial advantage over the now commonly used devices for the dynamic measurement of exertional compartment syndromes. While the number of patients with exertional compartment syndromes in this study was small, it appears that this device could be much more user friendly and provide even more reliable data than most of the other currently available devices for measuring compartment pressure.
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