INTERFACE PRESSURE AND STATIC STIFFNESS INDEX OF FOUR COMPRESSION SYSTEMS

1A Andriessen PhD, 2IKY Wong, PhD, 3M Abel PhD

1Andriessen Consultants & UMC St. Radboud, The Netherlands. anneke.a@tiscali.nl 2Head of School, School of Nursing, Hong Kong Sanatorium & Hospital, HK 3Head of Medical & Regulatory Affairs, Lohman & Rauscher, Germany

IKY Wong, MBL Man, OSH Chan, SF Chi, M Abel, A Andriessen.JWC. Vol 21; no 4; April 2012.

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Methods

Inclusion:

• Healthy male or female ambulant patients of > 18 years;

• Having healthy legs ABI >0.8 or a normal pulse volume recording;

• Patients had the ability to understand and communicate in Cantonese.

Exclusion:

• Allergy against one of the used materials;

• Arterial occlusive disease (ABPI less than 0.8);

• Ulcers on the lower limb;

• Lower limb oedema;

• Known history of dermatological problems such as eczema or cellulitis.

• The experimental study aimed to compare Interface Pressure (IP) and Static Stiffness Index (SSI) of four different compression systems that are currently in use for venous leg ulcer and lymphedema treatment of the lower limbs.

• Experimental study (N=52); Recruitment was at random; Patients gave informed consent; Local ethical committee aproval was obtained (Hong Kong Sanatorium and Hospital) .

IKY Wong, MBL Man, OSH Chan, SF Chi, M Abel, A Andriessen. JWC. Vol 21; no 4; April 2012.

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Working definitions

• Interface pressure (IP): Pressure exerted on the limb by compression materials, measured as sub-bandage pressure

• Stiffness: The degree of stiffness is demonstrated by the pressure increase per cm. increase in leg circumference

• Static stiffness index (SSI): The pressure difference between pressure measured at B1, in supine and in the standing position

• SSI > 10: The compression system has high stiffness and is considered to be inelastic

• SSI < 10: The system has low stiffness and is considered to be elastic

Mosti, G., Mattaliano, V., Partsch, H. Phlebology. 2008; 23: 6, 287–294. Partsch, H. et al. Eur J Vasc Endovasc Surg. 2005; 30: 4, 415–421.

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N=52 healthy subjects

LSB SSB VSB

IP every 15 minutes for 4 hours in supine, standing, siting, walking

IP every 15 minutes for 4 hours in supine, standing, siting, walking

IP every 15 minutes for 4 hours in supine, standing, siting, walking

Analyzed in the ITT analysis N= 52

Flow chart

CS

IP every 15 minutes for 4 hours in supine, standing, siting, walking

IKY Wong, MBL Man, OSH Chan, SF Chi, M Abel, A Andriessen. JWC. Vol 21; no 4; April 2012.

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IP measurements

• Portable Kikuhime (Harada Corp.) was used for IP measurements

• Repeatability: Error: >0.3mmHg, linear response: 5–50mmHg

• The sensor (3cm ø) was placed at point B1: located at the medial aspect of the leg, where the gastrocnemius tendon turns in its muscular part.

IKY Wong, MBL Man, OSH Chan, SF Chi, M Abel, A Andriessen. JWC. Vol 21; no 4; April 2012.

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Parameters & analysis

• Primary outcome measure:

Interface pressure measured in supine, sitting, standing and walking

and Static Stiffness Index

• ITT analysis: Parametric or non-parametric tests (SPSS:IBM Corp.)

Mann-Whitney U or paired t-test were used for intragroup and per

group comparisons of the IP measured in the different positions and over

time

IKY Wong, MBL Man, OSH Chan, SF Chi, M Abel, A Andriessen. JWC. Vol 21; no 4; April 2012.

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Results: IP in supine

p=0.05

N=52

mmHg SSB LSB VSB CS Paired T-test

Mean (±SD) 40.68 (±5.01) 48.12 (±4.57)

48.96 (±3.99)

37.82 (±0.58)

SSB, LSB, VSB vs. CS: p = 0.05

Median (range) 41 (39-60)

50 (44-59)

51 (46-60)

40 (39-41)

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Results: IP while walking

mmHg SSB LSB VSB CS Paired T-test

Mean (±SD) 56.11 (±5.01) 69.59 (±6.24)

66.21 (±4.02)

40.04 (±1.77)

SSB, LSB, VSB vs. CS: p = 0.05

Median (range) 57 (52-80)

73 (64-90)

69 (64-80)

42 (40-45)

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Results: SSI

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Conclusions

• All four compression systems were able to sustain an IP at proposed effective therapeutic levels

• IP and SSI information may enable clinicians to predict the frequency of bandage application, supporting an adequate and safe choice of bandage system

• A tubular compression systems may increase the patients’ participation in, and compliance with, compression therapy, thereby saving on costs and nursing time EP

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Thank you for your attention