In a study of interface pressure changes under compression bandages, Junjie Ning, Fedor Lurie (both Jobst Vascular Institute, Toledo, USA), and colleagues found that while pressure decreased over time under all studied bandages, the temporal pattern of pressure change varied among dressings. The authors conclude in the Journal of Vascular Surgery: Venous and Lymphatic Disorders that monitoring interface pressure is “essential” to maintain a desirable interface pressure during compression therapy.
Ning and colleagues detail that compression therapy is widely applied in the prevention and treatment of chronic venous disease. However, they note that its effectiveness “highly depends on the interface pressure,” which is often evaluated in the form of interface pressure at the ankle. “The consensus is that applying and maintaining a desirable interface pressure during treatment is an important goal of compression therapy,” the authors write.
Pressure loss under compression bandages is a “well-known phenomenon,” Ning et al state, but they stress that the current standard of care does not include interface pressure measuring, monitoring, and adjusting of bandages if pressure drops. Explaining why having this information is important, they detail that, “Knowing the expected change in pressure over time can help clinicians select the most appropriate bandage system and plan for adjustments if necessary.”
Ning and colleagues write that this was a prospective, single-centre, open-label randomised trial, the aim of which was to investigate the change in pressure over time under three different compression bandages, and to compare the temporal patterns of pressure change between them.
They investigated four-hour change of interface pressure in 10 volunteers with no venous disease or leg swelling. In 20 patients with venous ulcers, the changes in the interface pressure was measured after four hours, one day, and seven days of wearing bandages.
Ning et al detail that the three tested bandages were Smart Sleeve compression system (SSB; Carolon), Coban 2 (C2; 3M), and Profore Lite (PL; Smith & Nephew). The investigators measured pressure using PicoPress (Microlab) and Juzi Pressure Monitor (Juzo).
The authors report that the mean pressure loss during the first four hours in the volunteers under SSB, C2, and PL were 4.5mmHg, 3.7mmHg, and 6.6mmHg, respectively. In addition, they found that there was no significant difference in pressure loss between the three bandages, whether in the supine (p=0.59) or standing position (p=0.47).
In patients with venous ulcers, pressure dropped gradually over seven days under C2. However, for SSB and PL, interface pressure maintained relatively stable during the first day but decreased significantly afterwards.
At the seven-day time point, the mean pressure loss was 4.7mmHg (SSB), 7.7mmHg (PL), and 8.6mmHg (C2; p=0.017). Only SSB maintained a desirable mean pressure of higher than 30mmHg on the seventh day in venous ulcer patients.
In the discussion of their findings, the authors acknowledge two limitations of the present study. One of these limitations is that only four time points were selected, “which makes the analysis of temporal patterns imprecise,” they note, adding that this occurred because data from venous ulcer patients was collected during routine clinical visits, and it was impractical to ask patients to visit the clinic every day. They recognise that small sample size is also a limitation of the current study. However, they hope that this study “might set the floor for larger and more rigorous studies with longer follow-up that investigate the clinical outcomes based on monitored interface pressure”.
The key take-home message from the study, Ning et al stress, is that different compression bandages loose pressure at different time periods. “Some bandages may need an adjustment after 24 hours of wearing, while other bandages loose pressure gradually and do not have a specific time point for adjustment,” they explain. For this reason, they highlight the importance of monitoring interface pressure in order to maintain a desirable interface pressure.