Number 12
OPTIMUM INTERMITTENT PNEUMATIC COMPRESSION
STIMULUS FOR LOWER-LIMB VENOUS EMPTYING
K. T. Delis, Z. A. Azizi, R. J. G. Stevens, J. H. N. Wolfe and A. N. Nicolaides
Irvine Laboratory for Cardiovascular Investigation and Research Academic Vascular Surgery, Imperial College School of Medicine, St Mary's Hospital, London, UK
Eur J Vasc Endovasc Surg 19, 261-269 (2000)
Complete article available online at http://www.idealibrary.com
Objective: intermittent pneumatic compression (IPC) of the foot (IPCfoot), calf (IPCcalf) or both (IPCfoot+calf) augments calf inflow, and improves the walking ability and peripheral haemodynamics of claudicants (IPCfoot, IPCfoot+calf), largely due to venous outflow enhancement. This cohort study, using direct pressure measurements in healthy limbs, determines the optimal combination of frequency (2-4 impulses/minute), applied pressure (60-140mmHg), mode (IPCfoot - IPCcalf - IPCfoot+calf) and delay time of calf-to-foot impulse (0 s-0.5 s-1 s) that enables IPC to generate an almost complete and sustained decrease in venous pressure.
Results: (a) IPCfoot at 120 and 80mmHg generated lower venous pressure than that with 100 and 60mmHg (p = 0.036) respectively, for 2-4 impulses/minute; venous pressure differences between applied pressures of 140 and 120mmHg or between 80 and 100mmHg were insignificant. (b) Venous pressure with IPCcalf at 80mmHg was lower than that with 60mmHg (p = 0.036) (2-4 cycles/minute); differences in venous pressure between applied pressures of 140 and 100 mmHg or between 120 and 80mmHg were insignificant. (c) At applied pressures 60-140mmHg, IPCfoot+calf with one-second delay generated lower venous pressure than that with half-second delay (p = 0.036), the latter being more efficient than zero delay; increasing applied pressures produced lower venous pressure, but differences were small.
Venous pressure decreased with increasing IPC frequency (from 2 to 3-4/minute), at applied pressures 60-140mmHg.
Conclusions: IPCfoot+calf at applied 120-140mmHg, a frequency of 3-4 impulses/minute and one-second delay, provided the optimum intermittent pneumatic stimulus.
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Number 12
OPTIMUM INTERMITTENT PNEUMATIC COMPRESSION
STIMULUS FOR LOWER-LIMB VENOUS EMPTYING
K. T. Delis, Z. A. Azizi, R. J. G. Stevens, J. H. N. Wolfe and A. N. Nicolaides
Irvine Laboratory for Cardiovascular Investigation and Research Academic Vascular Surgery, Imperial College School of Medicine, St Mary's Hospital, London, UK
Eur J Vasc Endovasc Surg 19, 261-269 (2000)
Complete article available online at http://www.idealibrary.com
Objective: intermittent pneumatic compression (IPC) of the foot (IPCfoot), calf (IPCcalf) or both (IPCfoot+calf) augments calf inflow, and improves the walking ability and peripheral haemodynamics of claudicants (IPCfoot, IPCfoot+calf), largely due to venous outflow enhancement. This cohort study, using direct pressure measurements in healthy limbs, determines the optimal combination of frequency (2-4 impulses/minute), applied pressure (60-140mmHg), mode (IPCfoot - IPCcalf - IPCfoot+calf) and delay time of calf-to-foot impulse (0 s-0.5 s-1 s) that enables IPC to generate an almost complete and sustained decrease in venous pressure.
Results: (a) IPCfoot at 120 and 80mmHg generated lower venous pressure than that with 100 and 60mmHg (p = 0.036) respectively, for 2-4 impulses/minute; venous pressure differences between applied pressures of 140 and 120mmHg or between 80 and 100mmHg were insignificant. (b) Venous pressure with IPCcalf at 80mmHg was lower than that with 60mmHg (p = 0.036) (2-4 cycles/minute); differences in venous pressure between applied pressures of 140 and 100 mmHg or between 120 and 80mmHg were insignificant. (c) At applied pressures 60-140mmHg, IPCfoot+calf with one-second delay generated lower venous pressure than that with half-second delay (p = 0.036), the latter being more efficient than zero delay; increasing applied pressures produced lower venous pressure, but differences were small.
Venous pressure decreased with increasing IPC frequency (from 2 to 3-4/minute), at applied pressures 60-140mmHg.
Conclusions: IPCfoot+calf at applied 120-140mmHg, a frequency of 3-4 impulses/minute and one-second delay, provided the optimum intermittent pneumatic stimulus.