title: Venous haemodynamics of Jet Impulse Technology within a lower limb fibreglass cast: a randomized controlled trial.
abstract: OBJECTIVE
  We investigated popliteal venous haemodynamics of the VenaJet Jet Impulse Technology system within a below-knee fibreglass cast.
  
  
  METHODS
  Randomized controlled trial.
  
  
  METHODS
  Twenty-four healthy participants aged 18-54 had both feet placed within the Jet Impulse Technology system and were randomised for one or other leg to be within a below-knee fibreglass cast.
  
  
  METHODS
  Pacific Radiology, Lower Hutt, Wellington.
  
  
  METHODS
  The primary outcome variable was peak systolic velocity (cm/s) compared between legs with and without the cast at 60 min (after 10 min Jet Impulse Technology activation), using a mixed linear model and a non-inferiority bound of 4.8 cm/s. Secondary outcome variables were the difference in peak systolic velocity between the casted limb and the non-casted limb at baseline and 40 min after casting, and the difference in mean flow velocity (cm/s), vein diameter (mm), and total volume flow (L/min) between the casted limb and the non-casted limb at baseline, 40 and 60 min.
  
  
  RESULTS
  The mean (standard deviation) peak systolic velocity was 4.6(1.5), 4.8(1.1), 28.8(16.1), and 4.3(1.2), 4.8(1.4) and 29.3(19.0) cm/s at baseline, 40 and 60 min in the casted and non-casted leg, respectively. The difference (95% confidence interval) between cast and no-cast at 60 min was -0.8 (-6.5 to 4.9) cm/s,P= 0.78. The peak systolic velocity, flow velocity and total volume flow at 40 min were not statistically significantly different from baseline for both casted and non-casted limb.
  
  
  CONCLUSIONS
  In healthy volunteers, the popliteal venous haemodynamics of the Jet Impulse Technology system was similar between the legs with and without a below-knee fibreglass cast. In-cast Jet Impulse Technology may provide a non-pharmacological option for venous thromboembolism prophylaxis for lower-limb cast-immobility.
authors.affiliation: Medical Research Institute of New Zealand, Wellington 6021, New Zealand; Victoria University of Wellington, Wellington 6021, New Zealand.
authors.forename: Irene
authors.initials: I
authors.lastname: Braithwaite
authors.affiliation: Pacific Radiology Limited, Wellington 6024, New Zealand.
authors.forename: Stephen
authors.initials: S
authors.lastname: Mackintosh
authors.affiliation: Pacific Radiology Limited, Wellington 6024, New Zealand.
authors.forename: Samantha
authors.initials: S
authors.lastname: Buchanan
authors.affiliation: Medical Research Institute of New Zealand, Wellington 6021, New Zealand.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Schwarzenlander
authors.affiliation: Capital and Coast District Health Board, Wellington 6021, New Zealand.
authors.forename: Bernadette
authors.initials: B
authors.lastname: De Ruyter
keywords: Jet Impulse Technology; below-knee cast; lower limb immobilisation; prevention; venous haemodynamics; venous stasis; venous thromboembolism