Construction and calibration of a low-cost bandage pressure monitor

Measurement of Lower Leg Compression In Vivo: Recommendations for the Performance of Measurements of Interface Pressure and Stiffness

BACKGROUND

Interface pressure and stiffness characterizing the elastic properties of the material are the parameters determining the dosage of compression treatment and should therefore be measured in future clinical trials.

OBJECTIVE

To provide some recommendations regarding the use of suitable methods for this indication.

METHOD

This article was formulated based on the results of an international consensus meeting between a group of medical experts and representatives from the industry held in January 2005 in Vienna, Austria.

RESULTS

Proposals are made concerning methods for measuring the interface pressure and for assessing the stiffness of a compression device in an individual patient.

CONCLUSIONS

In vivo measurement of interface pressure is encouraged when clinical and experimental outcomes of compression treatment are to be evaluated.

Measuring sub-bandage pressure: comparing the use of pressure monitors and pulse oximeters

OBJECTIVE

To test the use of low-cost sub-bandage pressure monitors and pulse oximeters as part of a quality-control measure for graduated compression bandaging in leg ulcer clinics.

METHOD

Twenty-five healthy volunteers (mean age 40 years) providing 50 limbs were bandaged with a four-layer compression bandaging system. The ankle systolic pressure (ASP) was measured using a pulse oximeter (Nellcor NBP-40) before applying the graduated compression bandages. Interface pressure was measured by placing pressure sensors on the skin at three points (2cm above the medial malleolus; the widest part of the calf; and a point midway between them) in the supine and standing positions. The ASP was measured again with the pulse oximeter after the bandage had been applied, and the effect of the bandage on the ASP was recorded. The actual pressure created by the bandage was compared with the required pressure profile.

RESULTS

Interface pressures varied with change of position and movement. With the operator blinded to the pressure monitors while applying the bandages, the target pressure of 35-40mmHg at the ankle was achieved in only 36% of limbs ([mean +/- 95% confidence interval]; 32.3 +/- 1.6mmHg [supine]; 38.4 +/- 2.4mmHg [standing position]). With the help of the pressure monitors, the target pressure was achieved in 78% of the limbs. There was no correlation between the pressure monitors and pulse oximeter pressures, demonstrating that the pulse oximeter is not a useful tool for measuring sub-bandage pressures.

CONCLUSION

The results suggest a tool (interface pressure monitors) that is easy to operate should be available as part of quality assurance for treatment, training of care providers and education.

Interface pressure measurement: testing and selecting sensors

Interface — or contact — pressure measurements play a key role in the design of many patient support surfaces aiming to protect areas vulnerable to pressure ulceration. But testing and selecting appropriate devices can be problematic.

An evaluation of the Amputee Mobility Aid (AMA) early walking aid

The most popular early walking aid (EWA) in the United Kingdom (UK) is the Pneumatic Post-Amputation Mobility aid or PPAM aid. A disadvantage of this device is that it does not allow a trans-tibial amputee to flex or extend the knee during walking. The Amputee Mobility Aid (AMA) was developed to allow knee movement, enabling trans-tibial amputees to practise a more natural gait. The benefits of using EWAs include early walking, reduction in post-operative oedema and improvement in patient morale. This pilot study investigated the pneumatic bag/stump interface pressures of the PPAM aid and the AMA. In addition, the range of motion of the knee on the amputated side and the mechanical knee of the AMA were compared. The AMA was found to have higher interface pressures than the PPAM aid during standing and similar pressures during supported walking. Subjects using the AMA did flex and extend their knee during walking but through a reduced range of motion. There were no significant differences between the angular movements of the AMA's mechanical knee and the patient's knee within it.

Interface pressure measurements in leg ulcer management

Interface pressure measurements are undertaken in health care as a useful tool to assist in understanding the pressures that exist between the skin surface and another surface. Pressure monitors are utilized to measure pressures under compression bandages and pressure garments and in determining pressures between patients and support surfaces such as pressure-reducing mattresses and cushions. This literature review identified that many studies using these measurements are inadequately described, and that there are many variables such as the effect of time, posture and temperature associated with such measurements that may lead to misinterpretation of results. Studies utilizing interface pressure measurements should be interpreted with caution and measurement techniques could be improved.

A comparison of sub-bandage pressures produced with two multi-layer bandaging systems

Fourteen nurses with experience in the use of high-compression bandaging were asked to bandage the same limb with two different bandaging systems: the 'Charing Cross' four-layer regimen (System A), and a modified system incorporating two new bandages (System B). A sub-bandage pressure monitor was used to quantify the efficacy of the resulting bandaging for the two systems. The results indicated that there was no significant difference between site sub-bandage pressures achieved using the two bandaging systems. Sub-bandage pressure profiles, however, fluctuated with patient posture, the best profiles being obtained with System B and the patient in the sitting position.

The impact of a bandage training programme

This study measured the impact of a training programme on nurses' bandaging skills and aimed to establish whether any improvements are maintained over time. Two commonly used high-compression bandages were investigated using the Oxford pressure monitor. A quantitative approach was taken using a quasi-experimental, pre- and post-test design. Using a sample of 23 community nurses, data were collected by means of a self-rating questionnaire, structured observation and objective measurement. Nurses' knowledge and competence significantly improved following training. However, the maintenance of skills requires further investigation. Nurses tended to overrate their competency in bandaging compared with actual proficiency. More nurses achieved better proficiency scores when using one bandage type compared with the other, but this was not statistically significant.

Using a bandage pressure monitor as an aid in improving bandaging skills

This prospective study used a bandage pressure monitor to assess the bandaging skills of 16 nurses caring for patients with venous leg ulcers. Baseline measurements showed that only 50% of the nurses demonstrated bandaging skills that were adequate to good. However, by the end of the feedback/post-training session, 81% of those examined had reached this standard and this figure rose to 86% on recall. These data seem to support the view that the use of a pressure monitor is a useful adjunct in the teaching of bandaging skills.