Therapeutic factors did not significantly explain changes in the healing rate. The most influential factor in this model was ‘hours spent in a horizontal position’ for the venous only and all subjects groups. This study is the first study to quantify limb positioning in a community sample. This factor has not been measured by clinical studies that also investigated the effects o f compression and/or dressings. The more hours spent with limbs horizontal, the poorer the healing rate. This confirms the experience o f Bourne (1986a). High venous pressures were found in humans and animals when placed in a horizontal position (Bourne, 1986a). Decreased T cP02w as found in subjects with venous disease when recumbent with limb compression (Gaylarde et al., 1993). Conversely, elevation was found by Bourne (1986a) to reduce venous pressure. Elevation o f the limb at the level o f tw o pillows or more in subjects in this study was very uncommon, the mean being less than 1 hour. The participants often stated that they were ‘putting their legs up’ often demonstrating a supine position or a sitting dependent position. Footstools that were lower than lounge level were common. Both the number o f hours spent in a sitting dependent position, and hours with limbs elevated, were negatively correlated with hours spent in a horizontal position. The exact angle o f the limbs to the torso was not measured in this study.
The subjects when asked often stated they had no difficulty in positioning their limbs as requested. This may suggest that misinformation and misinterpretation may be occurring. Bourne (1986b) recommended elevation o f limbs to at least 20 inches above the torso for three hours. Eighty percent o f subjects in this study did not elevate their legs. The ability o f older people with arthritic joints and perhaps joint replacements to place their limbs in that position for a substantial length o f time is often impaired. This may be a plausible explanation and an unhelpful adaptation o f advice could be occurring.
In the venous-arterial group, the investigator replaced the horizontal position hours with the number o f hours spent in a dependent position, with no significant improvement in the model. This result would be in conflict with the findings o f Creutziq et al. (1988), where dependence improved TcPC>2. There were very few severe arterial disease cases
in this study, demonstrating the usual caseload o f CHN’s.
An issue overlooked in this study and in others, is the potential for changes in position to improve blood flow for a short period. Many studies follow a series o f changes in position (Creutziq et al., 1988), such as reclining to standing position, increasing the TcPC>2 in the ulcer area in venous and arterial disease (Reddy et al., 1986;
Allen & Goldman, 1987). There may be some cumulative effect. The possible mechanism was referred to by Beaconsfield and Ginsburg (1970)— baroreceptor response decreases peripheral blood flow with posture changes, and increases the TcPC>2.
Where venous hypertension is being counteracted by external compression, changing o f position may be worthy o f further exploration in the venous-arterial ulcer group.
The findings from this study neither support or refute the potential o f limb elevation to decrease venous hypertension and oedema. There is support for the belief that resting for long periods with limbs horizontal to the torso is associated with poorer healing. The scale used to determine average daily hours spent in various activities and positions was designed from a previous ABS survey (1988) and is subject to recall bias.
Hours spent resting could be a measure o f more generalised declining health, accordingly associated with poorer healing in all groups. Also, as health is equated to mobility in older people, perhaps long hours o f resting promotes a sense o f ill-health in older people, and indirectly resulting in poorer healing. Nevertheless, 59% o f the non healers reported that they were in good health.
Limb compression was not found to be a significant contributor to the healing rate. Very little therapeutic compression (40-60m m H g at ankle) was being delivered (37%) to the cases for which it was appropriate. This has been previously highlighted by Jopp- McKay et al (1991) where emphasis was placed on dressings in ulcer treatment rather than compression. Cornwall et al. (1987) has suggested that even low levels o f compression increase venous refilling time and are beneficial. If there was indeed any improvement in venous filling, this did not improve healing rates in this sample. The use o f over-stretched bandages, and anecdotal evidence o f clients refusing increased
compression, was a common experience. The cost o f bandages was often cited as the problem in this study and in others (Jopp-McKay et al., 1991). Other cases felt the treatment was not helpfiil, and uncomfortable.
Three issues need to be emphasised. First, in most clinic studies researchers have tested the pressure o f the bandages with medical stocking gauges as used in this study. Clinicians, including nurses and doctors, being known to vary in their pressure application, do not have access to such equipment. Application o f compression therapy needs to closely match the research conditions under which the therapy was tested, including compression pressure monitoring. Second, compression gradients are contingent upon the limb girth profile (Cornwall et al., 1987). Applying bandages to oedematous limbs often results in extreme pressures without a satisfactory gradient (20 mmHg) between the ankle and the knee (Cornwall et al., 1987; Bourne, 1992). Third, older arthritic people may be unable to manage these bandages (Amaral, 1986; Bliss & Schofield, 1993). Modifications are needed to allow older people sufficient resources to afford therapeutic bandages, and to easily manage bandage removal and replacement. Clinical trials involving this therapy need to include more representative people, and not be performed on younger samples as seen in Salim’s (1991) study with a mean age o f 56 years.
The interaction between compression and levels o f activity requires further investigation. Previous studies by Blair et al. (1983) and Salim (1991) demonstrated that healing rates were improved with compression therapy at therapeutic levels in addition to standard dressings. Independent effects o f compression on healing have not been demonstrated. There is a sound theoretical basis for external counteracting pressure in ambulatory patients, but the application o f high levels o f compression (40-50 mmHg) to this immobile sample (56% limited mobility; 60% walking [<1 hour]) seems debateable. Lower pressures are recommended for horizontal positions. Gaylarde et al., 1993, had found decreased T c P 0 2 when subjects were recumbent with external pressures o f 40-50 mmHg. This study may have more adequately assessed low compression (the mean ankle pressure in this study being 29 mmHg) in persons spending long hours reclining, as the participants spent many hours in horizontal positions. For this regime, no relationship to healing rate was found.
The length o f time that compression therapy is maintained per day or per week may be critical. No measure was made o f how long the bandages were kept on. The high frequency o f the nurses visits makes this possibility less understandable. These results may be, in part, a reflection o f the low levels o f therapeutic compression being received.
Dressings and diuretic usage were not found to be significant contributors to the healing rate. The relationship between dressing score (total o f 15 desirable attributes o f a dressing) and healing rate was not statistically significant, although it was negatively
related— the more desirable attributes the dressing has, the more improved the healing rate. The extensive use o f dressings with desirable attributes was evidenced in the mean dressing score o f 32. Many o f the dressings used for these clients are expensive. The evidence does not suggest that this is a major contributing factor to healing, supporting previous findings by Skene et al. (1992). Refocussing o f interventions towards factors which really influence healing is desirable. There may be subjective benefits for the client and nurse for some dressings, but this issue was not assessed.