Schroeder HP, Coutts RD, Billings E Jr, Mai MT, Aratow M.
The changes in intramuscular pressure and femoral vein flow with continuous
passive motion, pneumatic compressive stockings, and leg manipulations.
Clin Orthop 1991 May;(266):218-26

Division of Orthopaedics and Rehabilitation, University of California, San Diego.

Intramuscular pressure was measured continuously in the deep compartment of the
calf and anterior thigh of volunteers while their legs were cyclically moved from
0 degrees to 90 degrees back to 0 degrees (angle of knee flexion) in an anatomic
continuous passive motion (CPM) device and a nonanatomic CPM device. Femoral
venous flow was measured continuously using a thermodilution technique in
volunteers while their legs were moved in both CPM devices, during inflation of a
pneumatic stocking, and during several leg manipulations. Baseline intramuscular
pressures in the deep calf and anterior thigh were 10.0 +/- 1.9 mmHg and 4.9 +/-
1.9 mmHg, respectively (mean +/- standard error). Both the anatomic and
nonanatomic CPM devices produced a statistically significant maximal increase in
pressure in the calf. By contrast, only a decrease in pressure occurred in the
thigh with both devices. Baseline femoral vein flow measured by the
thermodilution technique was 311 +/- 38 ml per minute. Significant increases in
femoral vein flow were seen with both CPM devices. The maximal flow produced by
the anatomic CPM was 1199 ml per minute and was approximately four times higher
than baseline flow and approximately 1.4 times the maximal flow change seen with
the nonanatomic CPM (836 ml per minute). The greatest net increase in flow was
observed between 60 degrees and 90 degrees of knee flexion with both devices.
Overall, passive straight-leg elevation produced the largest flow (1524 ml per
minute), followed by the anatomic CPM and nonanatomic CPM, and then by active
ankle dorsiflexion(640 ml per minute), pneumatic stocking inflation (586 ml per
minute), manual calf compression (532 ml per minute), and passive dorsiflexion
(385 ml per minute)(ABSTRACT TRUNCATED AT 250 WORDS)