Pulsed Doppler in simulated compartment syndrome: a pilot study to record hemodynamic compromise

Abstract

Background: Acute compartment syndrome occurs when the tissue pressure within a closed muscle compartment exceeds the perfusion pressure. We observed diastolic retrograde arterial flow (DRAF) in 2 patients in the arteries proximal to compartment syndromes in injured limbs. We hypothesized that DRAF may represent an early sign of compartment pressure increments.

Methods: We mimicked compartment syndrome by using a cuff to produce external compression of the forearm at increasing pressures. We correlated the applied pressure with brachial artery blood flow, velocities, and retrograde flow. We studied the brachial artery at baseline, at external compression of 40 mmHg applied to the forearm, at forearm compression equal to the patient's diastolic blood pressure (DBP), and at forearm compression equal to the patient's mean arterial pressure (MAP). Evaluations included Doppler velocities and DRAF percentage (%). Using a ROC analysis, we selected a DRAF (%) cutoff value for the identification of patients with an applied external pressure equal to or greater than their DBP and calculated its sensitivity and specificity.

Results: Compared with baseline, DRAF (%) was increased at 40 mmHg (P<0.05), at DBP (P<0.05), and at MAP (P<0.05). DRAF (%) was strongly correlated with applied external pressure (r=0.92, r(2)=0.85). DRAF 40% presented a 100% sensitivity and a 93% specificity for identifying a compression equal to or greater than the patient's DBP.

Conclusion: DRAF (%) strongly correlates with the degree of external pressure applied to the brachial artery, suggesting it may represent a useful tool in the detection and evaluation of compartment syndrome.

Keywords: Compartment syndromes; hemodynamics; ultrasonography—Doppler.

Conflict of interest statement

The authors have no financial or proprietary interest in the subject matter of this article.

Figures

Figure 1.

Complete diastolic retrograde arterial flow in the femoral artery of a 23-year-old male with compartment syndrome.

Figure 2.

Complete diastolic retrograde arterial flow in the brachial artery of 72-year-old male with compartment syndrome.

Figure 3.

Pulsed Doppler images obtained from the brachial artery of a normal subject at baseline and as ascending pressure is applied to the forearm: A—external compression equal to diastolic blood pressure; B—external compression equal to mean arterial pressure; C—baseline; and D—external compression of 40 mmHg.

Figure 4.

A. Adjusted linear regression for the correlation of diastolic retrograde arterial flow percentage [DRAF(%)] and external applied pressure. B. Adjusted linear regression for the correlation of DRAF(%) and the blood flow reduction percentage compared with baseline.

Figure 5.

Receiver operating characteristic analysis for the diastolic retrograde arterial flow percentage [DRAF (%)] cutoff values for identifying an applied external pressure greater than or equal to the patient's diastolic blood pressure. Diagonal segments are produced by ties.