Quantifying the degree graduated elastic compression stockings enhance venous emptying.

OBJECTIVES

Graduated elastic compression (GEC) stockings reduce reflux and venous volume but their performance on augmenting venous return is unproven. The aim of this study was to quantify the ability of stockings to increase venous outflow from the leg.

DESIGN

A prospective study comparing venous emptying without compression, versus class 1 (18-21 mmHg) and class 2 (23-32 mmHg) compression, using air-plethysmography (APG).

METHODS

The right legs of 20 healthy subjects were studied supine. A 12-cm thigh-cuff was inflated in 10 mmHg steps from 0 to 80 mmHg while the corresponding increase in calf volume was recorded using the APG sensor calf-cuff. At the 80 mmHg plateau, the thigh-cuff was released suddenly to measure the unrestricted venous emptying. Venous return was assessed by: (a) identifying the incremental thigh-cuff pressure causing the maximal incremental increase in calf volume (IPMIV); (b) measuring the percentage reduction in calf volume in 1 second following thigh-cuff release - outflow fraction (OF); (c) time to empty 90% of the venous volume - venous emptying time (VET90).

RESULTS

Median and inter-quartile range (IQR) baseline values of IPMIV, OF, and VET90 without compression were 20 mmHg (range: 20-30 mmHg), 44% (39-50%) and 13 seconds (8.8-15.9 seconds), respectively. These improved significantly with all stockings. The application of any stocking raised the median IPMIV by 30 mmHg. The change from a class 2 stocking compared with no stocking versus the change from a class 1 stocking to no stocking had a more pronounced effect (p < .005). After sudden thigh-cuff deflation, the venous emptying was 41-45% greater and 9-10 seconds faster with all stockings (p < .005).

CONCLUSIONS

This is the first study to quantify the venous return of below-knee GEC stockings. Assessments of stockings in augmenting venous return may be of use as a way of optimising compression for individual patients unresponsive to standard conservative treatment.