SCD Guide for Occupational Therapists – Overview, Uses, Contraindications, Tips, Research on VTE & DVT

Check this SCD out:

I have not seen an SCD like this one before. I like how the model is on her phone. It’s not like she can go anywhere while it is being used. All joking aside, let’s talk about the latest research behind SCDs, its uses, contraindications, and other tips based on my experience in acute care and acute rehab.

Uses

SCD stands for sequential compression device. SCDs are also known as “Intermittent Pneumatic Compression” devices or IPCs, for short.¹  They are ubiquitous in the hospital and found at the foot of patient’s beds. I never actually looked into the latest research behind it, but I heard from one ICU nurse that they are ‘useless’. I found this patent on Google patents filed in 1980:

Abstract: A pressure generating device for applying compressive pressures from a compressor against a patient’s limb through means of a flexible, pressurizable sleeve which encloses the limb having an overpressure circuit which causes venting of the pressurizable sleeve and termination of power to the compressor in the event of the pressure assuming an excessive value. The sleeve has a ventilation chamber and a controller which generates electrical signals to actuate a solenoid controlled valve to periodically connect the compressor to the ventilation chamber during cooling cycles. ² 

I didn’t do a deep dive into when it was invented, perhaps around this time. According to the University of Michigan Health System,

“Sequential Compression Device (SCD) is a method of DVT prevention that improves blood flow in the legs. SCD’s are shaped like “sleeves” that wrap around the legs and inflate with air one at a time. This imitates walking and helps prevent blood clots. You should wear your SCD’s any time you are in bed or sitting in a chair. The SCD’s must be removed for walking.” ³ 

SCDs are also used as an intervention for lymphedema.

EBP

Dhakal, P., Wang, L., Gardiner, J., Shrotriya, S., Sharma, M., & Rayamajhi, S conducted a retrospective cohort study (n=30,824) to evaluate the effectiveness of sequential compression devices (SCDs) for venous thromboembolism (VTE) prevention in medically ill hospitalized patients. Their results were VTE was seen in 47 out of 20,018 patients on SCDs (41 DVT, 6 PE) and 20 out of 10,819 patients without SCDs (14 DVT, 6 PE). Risk-adjusted analysis showed no significant difference in VTE incidence in the SCD group compared to NONE (odds ratio 0.99, 95% confidence interval 0.57-1.73, p=0.74). Their conclusion was comopared to the NONE group, SCDs are not associated with decreased VTE incidence during hospital stay. ⁴ 

I believe there are some barriers to studying the efficacy of SCDs in clients for VTE. First are confounding variables. When doctors order medications for VTE prophylaxis such as blood thinners, this creates an additional variable if you are to determine if SCDs are working or not. The groups would have to be SCD only, other interventions such as medication only, or no intervention at all. Then you also don’t know how this same patient would have responded to any one of these treatments alone and the significance of each intervention.

Another barrier is wearing compliance as affected by the patient and/or medical staff such as nurses following an SCD wearing protocol. A patient may neglect to wear it as recommended, a nurse may be busy and not have an opportunity to educate and promote wearing the SCD, or any other factor.

“Among nurses, the main cause of poor compliance with SCD therapy is lack of education about proper use of this therapy and about VTE pathophysiology. Many nurses have received only limited education on sleeve sizing, application, and duration of SCD therapy. Lack of available equipment also may reduce compliance. Some nurses with high patient workloads fail to reapply SCDs after ambulation, a bath, or assessment. A 2009 study found SCD compliance increased 4% after nursing staff were educated on proper use of SCD.” ^5 6 

The Dhakal study addressed these very concerns of mine in their limitations:

Our analysis excluded high-risk patients who received anticoagulants with or without SCDs and thus may not represent all hospitalized medical patients seen in clinical practice. The compliance and appropriate use of the SCDs could not be verified in all cases. ⁷ 

This next study was more of my wheelhouse. Dennis, M., Sandercock, P., Graham, C., Forbes, J., Smith, J conducted a RCT to determine whether or not intermittent pneumatic compression reduces the risk of post-stroke deep vein thrombosis and to estimate its cost-effectiveness. Sample size: they allocated 1438 patients to IPC and 1438 to no IPC. Results: The primary outcome [DVT] occurred in 122 (8.5%) of 1438 patients allocated to IPC and 174 (12.1%) of 1438 patients allocated to no IPC, giving an absolute reduction in risk of 3.6% [95% confidence interval (CI) 1.4% to 5.8%] and a relative risk reduction of 0.69 (95% CI 0.55 to 0.86). ⁸ 

The IPC group resulted in a reduction, albeit a “small” 3-4% reduction. I guess that is not bad, but much lower than I expected it to be. Would I use an SCD if there was a 3-4% chance of reduction in VTE? You bet. Patients tell me they actually like how they feel most of the time. Combined that with medication for VTE prophylaxis and mobilizing out of bed when safe, I would feel pretty good about it, right? Or so it seems.

I found a third older prospective cohort study done in 2006 of 141 ICU patients who received DVT prophylaxis: SCD, subcutaneous unfractionated heparin (UFH), or both.

Based on these 3 studies in isolation (there’s plenty more in the literature), SCD’s work somewhat, but not as well as heparin. When combined together, they seem to do worse based on the 2006 study. Personally, I would go for the heparin and try to mobilize ASAP when safe if I was a patient. If I was developing edema as well in my lower extremities, I would then throw on the SCDs as an added intervention.

Lymphedema

SCDs seems to also do a pretty good job at controlling lymphedema – when worn correctly, there is good compliance, etc, but this was not the focus of my research. If this is your primary intention for SCD use, I recommend you look at the literature more.

More about SCDs

• SCDs have different pressure features and settings, e.g., 35 and 45 mmHg.
• They come in different sizes.
• Each manufacturer will have different sizing and wearing recommendations.
• SCDs should be doffed when the patient ambulates.
• Patients frequently remove the sleeves without notifying the nurse so the effects of SCD therapy are often short-lived. Maybe they should have alarms? That would be annoying, more alarm fatigue. Come to think of it, the newer models beep when they detect that they are not “used properly”.
• To ease sweating, initiate the cooling system on the SCD pump; to relieve itching, use cornstarch. Some patients complain of discomfort from tight sleeves if they develop edema during their stay; in this case, the sleeve should be resized. ⁶ 

General SCD Protocol

(This is more for nurses, but it is good to know what is happening.)

1. Physicians must order SCD therapy. The SCD therapy order is based on a completed physician VTE risk assessment (mandatory for all acutely admitted patients).
2. Knee-length SCDs will be applied unless the physician specifically orders thigh-length SCDs.
3. A baseline skin assessment and neurovascular assessment must be completed.
4. Patient education
5. Measuring fit.
6. Reapplying and discontinuing use as necessary. (OT role in observing changes and donning/doffing as needed).

Occupational Therapy Involvement

Educate patients about what SCDs are intended to do. You now know some of the research and you can share it with them too. OTs will most likely interact with SCDs when they mobilize: assisting to don and doff the cuffs and managing the pumps. They should also manage the wires and tubing to prevent fall hazards, as they are at the foot of the bed where other staff and the patient’s neighbor may ambulate near.

• Learn how to size the cuffs (even though nursing is responsible).
• Learn how to don and doff the cuffs (direction, inside out, placement on an extremity, most likely lower extremities).
• Learn how the machines work.
• Learn how to connect and disconnect the tubing.
• Learn the contraindications.

Contraindications

• SCD therapy is contraindicated in patients with documented deep vein thrombosis.
• It’s probably not a good idea to put them on patients with poor skin integrity, e.g., sores, necrosis, infection, wet and weeping, redness, active bleed, etc. – use your professional reasoning here. When in doubt, ask the RN.
• Suspected DVT until ruled-out
• Pain
• Redness
• Increasing edema/swelling
• Poor sensation (especially if worsening)
• I am not sure if SCDs can be placed over staples, e.g., post-op and dressings. Probably not.

The Kendall SCD 700 states these contraindications in their user manual:

• Dermatitis
• Vein ligation (immediate postoperative)
• Gangrene
• Recent skin graft
• Severe arteriosclerosis or other ischemic vascular disease
• Massive edema of the legs or pulmonary edema from congestive heart failure
• Extreme deformity of the leg
• Suspected pre-existing deep venous thrombosis

The system may not be recommended for use with foot cuffs on patients with:

• Conditions where an increase of fluid to the heart may be detrimental
• Congestive heart failure
• Pre-existing deep vein thrombosis, thrombophlebitis, or pulmonary embolism ¹⁰ 

General Tips for OTs

• Stay with the patient and watch the SCD for a full inflate/deflate cycle and ask the patient how it feels. If altered, monitor non-verbal expressions for pain or discomfort.
• Inform the RN if you made any changes, e.g, the SCD was on, but you decided to leave them off after returning the patient back to bed.
• Prevent trip hazards when mobilizing patients out of bed, don’t just let SCDs and tubing them fall on the floor.
• Remove SCDs e.g., the sleeves for bathing, exposing the skin.
• Caution the patient never to ambulate with the sleeve in place due to the risk of falling.
• Make sure the sleeve is removed only for a short time daily (compliance to protocol).
• Make sure you don’t put them on upside down.
• Consider the positioning and comfort of the patient, e.g, bed elevation, lower extremity elevation, etc.
• Remember to lower the bed to prevent falls out of bed if recommended by your facility.
• Replace worn-out or soiled equipment or inform nursing about it.
• Consider how SCDs will interfere with dressing, particularly lower body dressing. The cuffs probably won’t work as well over pants, e.g., jeans. You can practice donning/doffing lower extremities and assist with changing patients back into their hospital gowns to comply with the SCD protocol. Educate the patient about why you are doing this.
• Help nursing staff with wearing compliance by asking patients how long they have been wearing the SCD and if they have taken it off themselves (and for how long).
• Some newer beds have outlets at the foot of the bed so power cords won’t have to run along the bed from the head of the bed’s wall outlet. Look under the foot of the bed for any outlets.

Happy squeezing!

Sources

1. http://www.clotcare.com↑
2. https://patents.google.com/patent/US4396010A/en↑
3. https://www.med.umich.edu/1libr/NursingUnits/SCD.pdf↑
4. Dhakal, P., Wang, L., Gardiner, J., Shrotriya, S., Sharma, M., & Rayamajhi, S. (2019). Effectiveness of sequential compression devices in prevention of venous thromboembolism in medically ill hospitalized patients: a retrospective cohort study. Turkish Journal of Hematology, 36(3), 193.↑
5. Hilleren-Listerud AE. Graduated compression stocking and intermittent pneumatic compression device length selection. Clin Nurse Spec. 2009;23(1):21-4.↑
6. https://www.myamericannurse.com/enhancing-patient-outcomes-with-sequential-compression-device-therapy/↑↑
7. Dhakal, P., Wang, L., Gardiner, J., Shrotriya, S., Sharma, M., & Rayamajhi, S. (2019). Effectiveness of sequential compression devices in prevention of venous thromboembolism in medically ill hospitalized patients: a retrospective cohort study. Turkish Journal of Hematology, 36(3), 193.↑
8. Dennis, M., Sandercock, P., Graham, C., Forbes, J., Smith, J., & CLOTS (Clots in Legs Or sTockings after Stroke) Trials Collaboration. (2015). The Clots in Legs Or sTockings after Stroke (CLOTS) 3 trial: a randomised controlled trial to determine whether or not intermittent pneumatic compression reduces the risk of post-stroke deep vein thrombosis and to estimate its cost-effectiveness. Health Technology Assessment (Winchester, England), 19(76), 1.↑
9. Khouli H, Shapiro J, Pham VP, Arfaei A, Esan O, Jean R, Homel P. Efficacy of deep venous thrombosis prophylaxis in the medical intensive care unit. J Intensive Care Med. 2006 Nov-Dec;21(6):352-8. doi: 10.1177/0885066606292880. PMID: 17095499.↑
10. https://www.cardinalhealth.com/content/dam/corp/web/documents/Manual/kendall-scd-operation-service-manual.pdf↑