Pneumatic Compression Adds Little to DVT Prevention in ICU

SAN DIEGO — Intermittent pneumatic compression did not reduce the incidence of lower-limb deep vein thrombosis (DVT) for critically ill patients, a randomized clinical trial showed.

In a cohort of nearly 2,000 patients, DVT occurred in 3.9% of those receiving pneumatic compression, compared with 4.2% in a control group receiving only pharmacologic thromboprophylaxis (RR 0.93, P=0.74), reported Yaseen Arabi, MD, of the Ministry of National Guard Health Affairs in Riyadh, Saudi Arabia.

Nor did the adjunctive intervention significantly lower incidence of pulmonary embolism (0.8% vs 1%) or 28-day mortality (14.6% vs 16.5%), as reported here at the Society of Critical Care Medicine meeting and in the New England Journal of Medicine.

Previous studies have shown that pneumatic compression devices can reduce the risk of DVT, but to a lesser degree than pharmacologic thromboprophylaxis, Arabi said in his presentation.

But whether to use the combination had been unclear, which “resulted in inconsistencies in practice guidelines and considerable practice variation,” Arabi noted.

Many clinicians combine strategies because they believe it might provide a slight added benefit in preventing blood clots, commented Philip Verhoef, MD, PhD, of the University of Chicago, who was not involved in this study. However, these devices are not totally benign, and can sometimes prevent patients from mobilizing or can cause skin damage, he said.

“Pharmacology is always the rule, but we sort of assume there’s no harm in adding these pneumatic compression devices on. And older literature suggests that if you can’t do pharmacologic [thromboprophylaxis], adding these squeezers is better than nothing, especially if patients can’t get up out of bed and walk around,” Verhoef told MedPage Today. “What this study is saying is that it may not even be necessary to put these squeezers on at all.”

Medical, surgical, and trauma adult patients (≥14, ≥16, or ≥18 years of age, varying by site) were enrolled in the trial within 48 hours of ICU admission across 20 sites in Saudi Arabia, Canada, Australia, and India. Patients were included if they weighed at least 45 kg (99 lb), had no contraindications to pharmacologic thromboprophylaxis with unfractionated heparin or low-molecular-weight heparin, and clinicians expected at least a 72-hour ICU stay. DVT detected during the first 3 trial days was considered “pre-existing,” and these patients were excluded.

A computer-generated system randomized 2,003 patients 1:1 to either arm and stratified by trial site and type of heparin used. The intervention involved pneumatic compression applied to both legs for at least 18 hours per day, and removed every 8 hours for skin inspection. The intervention was discontinued if the patient attained full mobility, was discharged, or when DVT or pulmonary embolism was suspected or confirmed.

The majority of patients receiving pneumatic compression used knee-length sleeves (79.4%), though some used thigh-length (18.7%) and foot pumps (12.2%). Overall, those receiving the intervention wore them for an average 22 hours per day, for a mean 7 days.

Characteristics were similar across the intervention and control groups in terms of age, BMI, and Acute Physiologic Assessment and Chronic Health Evaluation (APACHE) II scores. In both groups, about half of patients came to the ICU from the emergency department (50.2% and 51%), and about three-quarters were medical admissions (79.4% and 77%).

A composite outcome of lower‐limb DVT, pulmonary embolism, or death from any cause at 28 days did not differ across patients receiving pneumatic compression compared to the control group (RR 0.97, 95% CI 0.83–1.14).

No adverse events occurred in either arm, and no difference was observed in terms of the average number of days patients were free from vasopressors (both 28 days).

Arabi and colleagues noted the trial was primarily limited by the few DVT occurrences, which reduced the power of the trial for detecting clinically-relevant effects (a benefit as high as 40% or harm of up to 44%). The trial was also unblinded, and some patients did not have an ultrasonographic study.