Residual volume fraction during walking using wireless air plethysmography in patients with chronic deep venous disease.

OBJECTIVE: Traditional air plethysmography (APG) provides a quantitative measure of the residual volume fraction (RVF) after 10 tiptoe movements. The recent development of a wireless Bluetooth (Bluetooth SIG, Inc, Kirkland, Wash) APG device, the PicoFlow (Microlab Elettronica, Padua, Italy), enabled us to measure RVF during normal walking. The aim of our study was to compare the RVF obtained during tiptoeing with RVF obtained during normal walking in patients with deep venous pathology (ie, reflux and/or obstruction). METHODS: A total of 61 consecutive symptomatic patients (27 women and 34 men; median age, 46 years; range, 18-79 years) with chronic venous disease due to deep venous pathology (venous reflux or obstruction, or both) before treatment or persisting after intervention were included in the present study. Of the 122 total limbs examined, 79 were affected by deep chronic venous disease and 43 contralateral limbs were normal with normal deep veins and acted as controls. The APG examination was performed using the PicoFlow device using the standard examination technique. The RVF was calculated from the residual volume at the end of 10 tiptoe movements and also during normal walking. RESULTS: At the end of the 10 tiptoe movements, the mean ± standard deviation RVF was 27.0% ± 13.2% in the limbs with normal deep veins and 38.8% ± 16.9% in the limbs with deep chronic venous disease (P < .001). During walking, when a steady state in volume was reached, the RVF was 26.3% ± 17.8% in the limbs with normal deep veins and 43.1% ± 18.6% in limbs with deep venous disease (P < 0.001). A significant difference was found between limbs with normal deep veins and limbs with deep venous reflux, irrespective of which exercise was performed. However, the mean RVF between the limbs with normal deep veins and those with outflow obstruction in the absence of reflux was significant during walking (P = .012) but not during tiptoeing (P = .212). The mean RVF was higher in the C3 to C6 limbs than in the C0 to C2 limbs with tiptoeing (29.9% ± 14.5% vs 38.3% ± 17.0%; P < .006). Similar results were obtained with walking (29.2% ± 18.0% vs 42.4% ± 18.8%; P < .004). CONCLUSIONS: In limbs with normal deep veins and deep veins with reflux, the RVF measured during walking with wireless APG was similar to the RVF obtained during tiptoeing. However, in the limbs with outflow obstruction in the absence of reflux, the RVF during walking was higher than the RVF after tiptoeing. Our results have shown that the evaluation of RVF during walking is feasible and practical.

The Feasibility of Underwater Computerised Strain Gauge Plethysmography and the Effects of Hydrostatic Pressure on the Leg Venous Haemodynamics.

BACKGROUND: Strain gauge plethysmography (SGP) is employed to evaluate venous drainage of the lower leg. METHODS: In this study, SGP was used to evaluate the effects of the hydrostatic pressure (HP) of water on venous volume (VV), expelled volume, and ejection fraction (EF) in 22 healthy legs before and during immersion in water. RESULTS: HP reduced VV by 100% and even more during underwater (UW) exercise, making calculation of the UW EF possible. DISCUSSION: UW SGP is feasible and indicates that HP improves venous haemodynamics. This study suggests that including UW leg exercise in the rehabilitation protocols of patients with chronic venous disease may be useful. KEYWORDS: Strain gauge plethysmography, Underwater compression, Underwater ejection fraction, Underwater venous volume.

Underwater Sonography of Leg Veins.

OBJECTIVES: Hydrostatic compression (HC) occurring during body immersion is considered beneficial for venous return from the lower limbs. No study has evaluated the effects of HC on the veins of the lower limbs using duplex ultrasound (DU). The purpose of this study was to use DU to evaluate the morphology and flow of the leg veins during immersion. DESIGN: The femoral and great saphenous veins were evaluated before and during immersion in a specifically built pool, in normal and varicose limbs. RESULTS: HC reduces vein size in both normal and varicose limbs. During immersion spontaneous flow increases whereas when present, blood reflux decreases. DISCUSSION: This pilot, proof of concept study has demonstrated the feasibility of DU investigation of leg veins during immersion. Larger series of underwater DU evaluations of normal and varicose legs are necessary to quantify and better explain the effects of HC on the veins of the lower limb.