EUROPEAN PRESSURE ULCER ADVISORY PANEL

Nutrition
Before considering methods of relieving pressure, we should say a word about nutrition. Once we understand the speed with which pressure injuries can develop, it is obvious that trying to improve nutrition can play no part in the acute prophylaxis of pressure sores. We are talking about hours not days or weeks, and although we can, and should, give intravenous fluids to relieve dehydration during this time, we can do nothing to improve nutritional status. The patient will have come into hospital, or have presented in the community, either well or ill-nourished and this cannot be changed in time to make any difference as to whether he will develop a pressure injury in the next 24 hours, the period we are concerned about. Most susceptible patients are too ill to want to eat and simply prescribing a food supplement without also providing effective pressure relief is futile and negligent.

Nutritional supplements may of course help with healing sores. Healing a large wound can require up to four times the normal protein intake,¹⁴ but here too, pressure-relieving regimes are more important. Most patients will start to eat and drink well once they have recovered from their acute illness and their sore is healing and they are not at risk of suffering new pressure injuries.

Posture
Posture is very important is preventing pressure injuries. From reading the literature with its emphasis on ‘early ambulation’,¹⁵ we might think we know all there is to be known about posture, whereas in fact this is one of the most poorly researched areas in all medicine. Although studies have been carried out demonstrating the ill effects of unnecessary bed rest,¹⁶ there is no ‘effective medicine’ base for nursing sick and postoperative patients in chairs rather than in bed. On the contrary, it is known that sleep is essential for healing;¹⁷ that ill and elderly patients suffer from postural hypotension, especially after meals;¹⁸ that urine output is reduced in the upright posture in frail elderly patients;¹⁹ that many patients become almost beside themselves with exhaustion trying to remain upright;²⁰ that exhaustion decreases peripheral blood flow;²¹ that sitting in chairs causes oedema²² and circulatory stasis in the legs and feet.²³ The effect of nursing immobile patients in chairs rather than in bed on the incidence of venous thrombosis has not been studied. Putting the feet on a footstool increases pressure on the heels and pelvic area. Pressure-relieving chairs or cushions are much less effective than pressure-relieving mattresses in bed and do nothing to prevent postural stress and fatigue.

In the 1990’s, Gebhardt²² carried out a crossover study at St George’s Hospital, London, on the effect of unlimited periods spent in chairs on postoperative recovery in elderly orthopaedic patients compared with limited chair nursing. There were 103 and 100 patients in the unlimited and limited groups respectively. In the unlimited group, between 10% and 18% of patients were out of bed for 4–8 hours daily. Immobile patients spent longer in chairs than mobile patients suggesting that the mobile patients lay down when they felt fatigued. In the limited group, virtually no patients sat out of bed for longer than six hours maximum and the majority were nursed either in bed or were up for not more than two hours per session.

Subjects were assessed pre-operatively and on the 3rd, 7th, 10th and 14th day post-operatively. Patients in the unlimited chair nursing group were found to have significantly more fatigue (self perceived using a visual analogue scale) compared with the limited group, 69/103 compared with 41/100 and more tachycardia (pulse rate >100/min), 54/103 compared with 32/100. These indices were shown by uni-variate analysis to be solely associated with chair nursing policy. Hypotension (systolic bp <100mmHg) was also more common in the unlimited compared with the limited group, 14/103 and 3/100 respectively but the difference was not statistically significant. There was no difference in the two groups in oedema in the operated leg when assessed before rising in the morning, but by the afternoon 35/102 patients in the unlimited group had developed oedema compared with 6/99 in the limited group (excluding patients with bilateral surgery). Incidence of oedema in the unoperated limb was also significantly different, 37/102 compared with 11/99.

There was no significant difference in the proportion of patients developing chest or urinary tract infections in the unlimited and limited groups, 18/102 and 13/98 and 11/103 and 7/100 respectively, but the number developing constipation (no bowel movement for 3 days) was significantly greater in the unlimited compared with the limited group, 64/103 and 32/100. (The ward in which the patient was nursed and the type of surgery were also found to be significant factors here).

All patients in the study were nursed on pressure relieving mattresses (pressure-reducing foam or large celled-alternating pressure overlays) from the day of admission for fracture patients and from the day of operation for planned surgical patients. This probably accounts for the low incidence of pressure sores, 9/103 in the unlimited compared with 0/100 in the limited group. In a similar study in another hospital, Gebhardt and Bliss²⁰ found a much higher incidence of sores: 63% in patients on unlimited compared with 7% in those on limited chair nursing. Patients in this older study were more highly at risk, median Norton Risk Assessment Score 11 compared with 19–20 at St George’s, and the unlimited chair nursing group were generally sat out of bed for a longer period, median 6 hours. In both studies, patients in the unlimited group were slower to achieve independent mobility. In the St George’s study the difference was 8.4 compared with 5.6 days, with equivalent delays in discharge, 14.0 compared with 11.6 days, differences which were statistically significant.

In a review of bed rest policies published in the Lancet last year¹⁶, the authors concluded that ‘perhaps the patient is the best judge of the amount of rest required’. Gebhardt’s results, as well as growing recognition of the importance of patient autonomy, suggest that this should be seriously considered.

References

1.  Bennett L, Lee BY. Vertical Shear existence in animal threshold experiments. Decubitus 1988 1 (1): 18–24.
2. Scales J. Pressure sore prevention. Care Science and Practices 1982; 1(2): 9–17.
3. Neumark OW. Deformation, not pressure, is the prime cause of pressure sores. Care Science and Practices 1981; 1(1): 41–43
4. Le KM, Madson BL, Barth PW, Ksander GA, Angell JB, Vistnes LM. An in depth look at pressure sores using monolithic pressure sensors. Plastic and Reconstructive Surgery 1984; 74: 745–754
5. Gunther AR, Clark M. The effect of a dynamic pressure redi-stribution bed support surface upon systemic lymph flow and composition. J of Tissue Viability 2000; 10(3): (suppl): 10–15
6. Kosiak M. Etiology and pathology of ischaemic ulcers. Archives of Physical Medicine and Rehabilitation 1959: 40: 62–69.
7. Bliss MR. Hyperaemia. J of Tissue Viab. 1998; 8(4): 4–13.
8. Holloway GA, Tolentino G, De Lateur BJ. Cutaneous blood flow responses to wheelchair cushion pressure loading measured by Laser Doppler Flowmetry. In Lee BY, (ed) Chronic Ulcers of the Skin. New York: McGraw – Hill Book Company 1985: 57–67.
9. Piepoli M, Garrard ChS, Kontoyannis DA, Bernardi L. Auto-nomic control of the heart and peripheral blood vessels in human septic shock. Intensive Care Medicine 1995; 21: 112–9.
10. Bliss MR, Simini B. When are the seeds of postoperative pressure sores sown? British Medical Journal 1999; 319: 863–4.
11. Versluysen M. How elderly patients with femoral neck fractures develop pressure sores in hospital. British Medical Journal 1986; 294: 1311–1313.
12. First annual OR acquired pressure ulcer symposium. Advances in Wound Care 1998; 11 (suppl): 8–9.
13. Calianno C. Assessing the preventing pressure ulcers. Advances in Skin and Wound Care 2000; 13(5): 244–246.
14. Constantian MB, Jackson HS. Biology and care of the pressure ulcer wound. In: Constantian MB (ed) Pressure ulcers. Boston: Little, Brown 1980: 69–100.
15. Zuckerman JD. Hip fracture. New England J of Medicine 1996; 334: 1519–1525.
16. Allen C, Glasziou P, Del Mar C. Bed rest: a potentially harmful treatment needing more careful evaluation. Lancet 1999; 354: 1229–1233.
17. Oswald I, Adam K. Sleep helps healing. British Medical Journal 1995; 35(3): 124–132.
18. Matthias C. Orthostatic hypotension. Prescribers’ Journal 1995; 35(3): 124–132.
19. Guite HF, Bliss MR, Mainwaring Burton RW, Thomas JM, Drury PL. Hypothesis: posture is one of the determinants of the circadian rhythm of urine flow and electrolyte excretion in elderly female patients. Age and Ageing 1998; 17: 241–248.
20. Gebhardt K, Bliss MR. Preventing pressure sores in orthopaedic patients – is prolonged chair nursing detrimental? J of Tissue Viability 1994; 42(2) 51–54.
21. Wiles PG, Grant PJ, Jones RG, Knibbs AV, Hampton IFG. Lowered skin blood flow at exhaustion. Lancet 1986; II: 295.
22. Gebhardt KS, The effect of limited and unlimited chair nursing on post operative recovery in elderly orthopaedic patients. PhD Thesis, 1999.
23. Ashby EC, Ashford NS, Campbell MJ. Posture, blood velocity in common femoral vein, and prophylaxis of venous thromboembolism. Lancet 1995; 345: 419–21.

Part II will appear in issue 3/2.