Intermittent Pneumatic Compression (IPC)

Within 5 years after experiencing a deep vein thrombosis (DVT), 1 in 3 individuals will develop swelling and skin changes associated with post-thrombotic syndrome (PTS).¹ Graduated, high-compression bandages and stockings are effective at healing venous leg ulcers, preventing progression of PTS and managing lymphedema,² but are most effective in ambulatory individuals. How much does walking help, and could increased calf muscle activity enhance the benefits of recognized compression therapies?

Intermittent pneumatic compression (IPC) mimics rhythmic calf muscle contractions and increases venous blood flow. A German guideline³ recommends IPC to prevent post-surgical DVT, heal diabetic foot and venous ulcers, reduce edema and lymphedema, and improve compromised arterial circulation. Intermittent pneumatic compression increases fibrinolysis in ambulatory normal individuals, as well as those with PTS,⁴ underscoring its importance in managing more than just symptoms. The recent advent of portable IPC devices allows for patients to be mobile during therapy. This offers opportunities for continued IPC use after hospital discharge, while engaging in normal daily activities. If these devices work safely, they may improve consistency of use and outcomes. This month’s Evidence Corner summarizes a recent review of studies that extrapolated evidence of efficacy and safety for IPC devices from hospital use to all appropriate immobile patients across the continuum of care. The second featured study reported on the efficacy and safety of a portable IPC device in improving PTS outcomes in ambulatory patients, suggesting that the benefits of IPC extend beyond those who are inactive or immobile.

Reference: Partsch H. Intermittent pneumatic compression in immobile patients. Int Wound J. 2008;5(3):389–397.

Rationale: Experience has shown that IPC is useful in preventing lower limb edema in immobile patients who sit with their legs dependent. There is ample evidence for those in similar situations, but no specific reference for IPC use on immobile patients, for whom IPC is underused.

Objective: Summarize experimental and clinical findings to support a rationale for extrapolating use of IPC to improve venous and lymphatic return in immobile patients.

Methods: A systematic review of IPC use on indications that may be clinically relevant to immobile patients was performed. Mechanisms and clinical consequences of edema accumulation in patients with deficient venous and lymphatic return were described. The author summarized benefits, issues, and adverse effects of other edema-reducing modalities including diuretics, compression stockings, and bandages to compare safety and efficacy with IPC. Evidence on physiological parameters affected by IPC was tabulated and practical and clinical issues with using IPC in various settings, including home use, were reviewed.

Results: In addition to post-operative DVT prevention, evidence supports benefits of IPC use in patients with arterial occlusive disease, rheumatoid lower limb flexion deformities, fractures, reduced bone density, and in healing venous ulcers. By simulating the hemodynamic action of walking, IPC can enable nonambulatory patients to maintain pulsatile venous blood flow.

Among modalities used to control edema, long-term diuretic use can cause renal damage and ultimately increases edema. Compression stockings exert sustained pressure and are used to prevent the lower leg from re-filling with edema, but patient usage is often less than optimal. Sustained, graduated compression bandages can be applied at higher pressures, but professional training is required for effective application and to avoid complications. Moreover, these are expensive, and the less elastic bandages require ankle movement for efficacy. Intermittent pneumatic compression actively produces cycles of pressure waves simulating working and resting sub-bandage pressures even in patients who are not able to flex their ankles.

Substantial IPC evidence can be extrapolated to its safe, effective use in immobile patients. Most studies of IPC were conducted in hospitals for prevention of DVT. More studies are needed in other conditions and settings and to define optimal IPC doses for compression amplitude, frequency, and duration. Currently, no “gold standard” exists among IPC devices, and the evidence is insufficient as to which device to use for each indication when making clinical decisions.

Author’s Conclusions
IPC should be considered a “key front-line treatment” for applying active compression to immobile limbs to reduce edema, promote venous blood flow, and help expedite venous ulcer healing. Specific randomized, controlled trials (RCTs) are recommended to provide evidence for use of IPC in patients with limited mobility or activity.

Reference: O’Donnell MJ, McRae S, Kahn SR, et al. Evaluation of a venous-return assist device to treat severe post-thrombotic syndrome (VENOPTS). A randomized controlled trial. Thromb Haemost. 2008;99(3):623–629.

Rationale: PTS is the most common chronic complication of DVT. Severe PTS can disable individuals, reduce quality of life and increase healthcare costs. Typical graduated compression stocking therapy frequently provides minimal relief. Daily 2-hour sessions on stationary pneumatic compression pumps can relieve severe PTS symptoms, but it is costly and inconvenient.

Objective: Evaluate a new portable compression device, (Venowave® [V], Saringer Life Science Technologies Inc, Oakville, Ontario) for the treatment of severe PTS.

Methods: A prospective, placebo-controlled, double blind crossover study randomly assigned 32 adult subjects with severe PTS to receive either V or a placebo (P) for 8 weeks followed by a wash-out period of 4 weeks and then the other treatment for 8 weeks. Subjects were included if they had documented prior DVT, daily leg swelling with discomfort due to PTS, and a Villalta et al⁵ scale score > 14. Those excluded had non-DVT-related or unstable symptoms, peripheral arterial disease, peripheral neuropathy, or an existing venous ulcer. Each subject received a labeled, pre-packed pair of one V and one P device (called “active” venodevice A or B) at enrollment and wore them in designated order—donning the device in the morning and wearing it most of the day for the respective A or B 8-week interval. The battery-operated devices were identical in size, weight, and sound, but the V device motor transmitted motion to a plane 8 cm x 19 cm, displacing 16 cc/sec of calf tissue from distal to proximal in a sinusoidal wave of 1-cm amplitude, simulating calf muscle activity. The P device motor was turned on but was not connected to the plane; hence, no tissue was rhythmically displaced. Subjects, investigators, and research nurses were blinded to treatment. The primary outcome measure was a global rating of “clinical success,” which included patient-reported benefit, moderate symptom improvement, and willingness to continue V use for the index leg. The Villata scale measured PTS severity for both legs at baseline and follow-up. Quality of life was measured using the VEINES-QOL.⁶

Results: Of the 26 subjects who completed the crossover study, 80% (n = 20) continued compression stocking use during the study. “Clinical success” was reported in 10 subjects using only V, in 4 subjects using only P, and in 2 subjects during both V and P use. Fourteen subjects reported no “clinical success” for either device.

Nineteen subjects preferred V and 4 preferred P. VEINES-QOL and Villata scale scores were significantly better at interval end for the V than for the P device (P = 0.004; n = 24 and 25, respectively). Too few adverse events occurred to test for safety differences between V and P.

Authors’ Conclusions
In patients with severe PTS, the V device improved severity of PTS and venous disease-related quality of life compared to a similar placebo device.

Intermittent pneumatic compression is a recognized preventive measure for DVT worthy of active exploration in management of venous or lymphatic insufficiency and related conditions. Currently available IPC devices are often misused, as I have discovered during post-operative visits to friends officially “on IPC” whose IPC cuffs were draped over the end of the hospital bed or not turned on. In each case, DVT and PTS ensued. Such variability in care has confused IPC misuse with poor outcomes.

A second source of confusion is uncertainty about the optimal parameters for IPC use. Rigorous RCTs need to optimize safety and efficacy for IPC devices and explore parameters such as sequential versus nonsequential, and single or multiple-chamber compression, rest intervals, and amplitude, rates and intervals of increasing or decreasing compression as applied to the foot, calf, or leg. For outcome measures of these trials, the findings by O’Donnell et al suggest that validated Villata PTS scale and VEINES-QOL scores are more sensitive efficacy measures than patient ratings of global “clinical success.”

Portable devices described by O’Donnell et al and others⁷ make IPC an option for consistently managing edema in individuals across settings. These portable devices can be used under a wide range of conditions including long-duration travel, obesity, psychological states, spinal cord injury or other immobilizing conditions. Intermittent pneumatic compression merits further research to define its optimal conditions for safe and effective use in improving quality of life, and clinical and economic outcomes for patients with lower leg edema and/or PTS.

Laura Bolton, PhD, FAPWCA
Adjunct Associate Professor
Department of Surgery, UMDNJ
WOUNDS Editorial Advisory Board Member and Department Editor