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Obstetric care. Is there risk of pressure damage after epidural anaesthesia?

Author(s)

Caroline Hughes

Tissue Viability Nurse
Royal Shrewsbury Hospital
Mytton Oak Road, Shrewsbury SY3 8XQ

Contents
Published: August 2001
Last updated: August 2001
Revision: 1.0

Keywords: Obstetrics; Epidural anaesthesia; Pressure ulcers; Mattresses.

Abstract

Anecdotal evidence suggests that there is an increase in the incidence of pressure damage to women in labour. This appears to be associated with epidural anaesthesia. Epidural anaesthesia used to control pain in childbirth causes loss of sensation and a degree of motor block, which removes the women's reflexes and ability to reposition to prevent pressure damage. The large amount of fluids present during childbirth may also increase the risk of pressure damage, especially in association with shear and friction. A combination of unfamiliarity of pressure ulcer prevention techniques among midwives, and the type of delivery room equipment, that is currently available, may leave young healthy women at risk of developing pressure ulcers.


Introduction

Recent anecdotal evidence from the author's own area of practice has caused concern about the increase in the incidence of pressure damage to women during labour. A literature search identified a few articles, which expressed similar concerns. Newton and Butcher [1] reported '-that pressure sores are on the increase in maternity units across the country'. Malone [2] noted similar worries after carrying out an investigation to identify contributory factors in women who developed pressure ulcers. There appeared to be a strong relationship with the use of epidural anaesthesia.

The use of epidural anaesthesia is rising steadily and is the most effective method for providing analgesia during labour [3]. It seems that the risk of pressure damage has been underestimated. Smett et al [4] comment in their study, that the combination of motor block, lack of sensation, excessive pressure, medical history such as insulin dependent diabetes and vasomotor paralysis may explain the occurrence of pressure ulcers in young patients thought to be at low risk. Lack of spontaneous patient movement can be compared to that of paraplegics who get no sensory warning of impending ischaemia [5].

Background

There are many related factors in the development of pressure ulcers such as tissue distortion caused by shearing forces and unrelieved pressure. Pressure ulcers can develop in anyone exposed to risk factor such as impaired sensation, immobility and hypotension. Disabled, frail or unwell patients are acknowledged to be at risk. However if the person is perceived to be healthy, the risk may be overlooked. Malone [2] expresses the opinion that women in labour are at increased risk of developing pressure sores due to changes in obstetric practices, shortages of midwives, and increased invasive monitoring. Many of the changes in obstetric care, such as invasive monitoring techniques, have resulted in reduced mobility during labour, which, when added to the loss of sensation caused by epidural anaesthesia, may raise the level of risk considerably. If preventative measures are not taken, pressure ulcers may become inevitable.

Aetiology of pressure damage

It is generally thought that pressure ulcers occur as the result of a combination of extrinsic and intrinsic factors [6], [7].

Extrinsic factors during labour: The mechanisms that cause pressure ulcer damage are well known. Pressure, shearing forces and friction are three factors either singly or in combination, which will cause pressure ulcer development. The semi recumbent or supported sitting position is the posture most commonly encouraged for child birth in western culture [8]. The patient in the semi recumbent or supported sitting position is particularly at risk. Many authors have noted that there is a greater level of compressive force applied on the sacral area when the head of the bed is elevated [9], [10]. The enlarged uterus adds to this problem by increasing the pressure on the pelvis.

Friction: Although friction is not thought to be a primary factor in the development of pressure ulcers, it can exacerbate the stripping of broken epidermis or be the cause of an initial break in the skin [11]. The large amount of fluid present during childbirth may increase the risk of pressure ulcer formation because of increased friction and shear. If the surface on which the patient is being supported is moist this can lead to the patient's skin adhering to the damp surface leading to a rise in friction [12]. Macerated skin becomes soft and fragile and is thought to be more susceptible to damage [13], [14]. Poor manual handling techniques may intensify this problem.

Equipment: Specialist equipment has always been required in the labour ward. Hospital delivery beds are constructed to allow removal of the lower portion to convert it into a birthing chair. The mattresses used are designed in two sections, to allow the bottom section to be removed to facilitate delivery and examination. The join in the mattresses is located very close to where the sacrum is situated, giving rise to greater pressure and friction during the early stages of labour.

The copious amounts of body fluids present during delivery mean that mattresses need to be both sturdy and well sealed. These qualities required of the mattress may render it less able to provide pressure redistribution than would be desired. Thicker covers of non-stretch material result in the patients weight being suspended on the cover, causing a hammock effect [12], rather than the weight being absorbed into the foam.

The quality of the mattress is of great importance. Foam that has suffered heavy wear and tear will result in the mattress bottoming out, and will offer little or no support, with the patient eventually resting on the hard metal bed base.

Callum et al [15] state there is good evidence to support the use of high-specification foam over standard hospital foam for prevention of pressure ulcers in 'at risk' patients. Collier [16] went further and specified that this should be at least 5 inches deep. Many of the mattresses that are supplied for pressure ulcer prevention do not come up to this standard. In fact it appears that no British quality standard specification for pressure redistributing foam mattress exists at all.

Epidural anaesthesia

Advances in pain management during labour have led to many women choosing epidural anaesthesia to control pain during childbirth. The loss of sensation induced may be sufficient to remove the women's reflexes to reposition. In addition to this, many epidural anaesthetics induce a degree of motor block, removing the ability to reposition effectively. The body's own defense mechanism against the development of pressure ulcers is to shift weight throughout the day and night. Reduced mobility is thought to be one of the most important factors in increasing a person's risk of developing pressure ulcers and is probably the most frequently quoted factor [17].

Other physiological events that may contribute to the loss of integrity of the sacral skin include, engorgement of valveless epidural veins resulting in oedema, especially during episodes of expulsive effort in the second stage of labour [18]. In addition, epidural administration of local anaesthesia also causes vasodilation, which, owing to external pressure, may cause local shunting. This shunting could result in skin ischaemia and eventually in pressure damage [4], [5].

Other factors

Foetal monitoring leads and intravenous infusions may restrict movement. Both the labouring woman and midwife may feel concern at the absence of effective foetal monitoring when the woman is turned, to a lateral position. Previously women may have been lifted clear of the support surface for short periods. However recent manual handling changes have resulted in a 'no lifting' policy. These combined factors could result in ineffective repositioning for pressure relief or even no repositioning at all.

Furthermore the increasing numbers of midwifery practitioners entering midwifery training directly in recent years, means that many will have had no experience of prevention or management of pressure ulcers. On the other hand, midwives who have previously trained as general nurses may become unfamiliar with trends in prevention and management over time, because the risk of pressure damage is perceived to be low in the environment in which they work.

Conclusion

Clinical governance places a duty of responsibility on all health professionals. Effective care can only be provided when individual practitioners ensure that their knowledge and skills are up to date. Pressure ulcer prevention needs to be part of a comprehensive educational package to meet the needs of the practitioner and, perhaps, the patient too.

Many changes in health care yesterday, have major unforeseen consequences today. While it is easy to predict results with the benefit of hindsight, realistically it is never possible to be sure how things will work out. Changes in obstetric care such as epidural anaesthesia (for better pain management), improved manual handling policies (to protect health care workers) and technological developments such as feotal monitoring, all have their individual benefits but collectively and interactively, they have resulted in an increase in the potential for pressure ulcers in healthy women.

Having identified an existing problem it is now necessary to identify ways of moving forward. Whilst it is the responsibility of the individual practitioner to ensure that their knowledge and skills are up to date, in order to provide optimum care it is also necessary to access expertise through local professional networks.

Managing risk is a fundamental part of clinical practice and it is essential that equipment used is appropriate to the task. Mattresses for the labour ward must be of high quality and be audited regularly for signs of fatigue, soiling and damage. It is essential that all women in labour are assessed for risk of pressure damage; this should be included as part of their care plan. Women must be aware of the risks and encouraged to participate in their own care. It should be recognised that epidural anaesthesia may create a high risk of pressure damage. Offori and Popham [19] comment that anesthetists need to maintain vigilance to prevent exposing mothers to pressure damage after epidural anaesthesia.

Pressure ulcer prevention and treatment is an area that has traditionally come under the umbrella of nursing and thus of midwifery. However there is a real need for our medical colleagues and especially anesthetists, to acknowledge this problem too.

References

1. Newton H, Butcher M. Investigating the risk of pressure damage during childbirth. Br J Nursing 2000; 9(6): 20-6.

2. Malone C. Pressure sores in the labour ward. RCM Midwives Journal 2000; 3(1): 20-3.

3. Grond S, Meuser T, Stute P, Gohring UJ. Epidural analgesia for labour pain: a review of availability, current practices and influence on labour. Acute Pain 2000; 3(1): 31-43.

4. Smet IGG, Vercauten MP, De Jonge R, Vundelinckx GM, Heylen MD. Pressure sores as a complication of patient-controlled epidural analgesia after Caesarean delivery. Reg Anesth 1996; 21(4): 338-41.

5. Punt CD, Van Neer AFA, De Lange S. Pressure sores as a possible complication of epidural analgesia. Anesth Analg 1991; 73: 657-9.

6. Bridel J. The aetiology of pressure sores. J Wound Care 1993; 2(4): 230-8.

7. Bliss M. Aetiology of pressure sores. Rev Clin Grenotol 1993; 3: 379-97.

8. Bennet VR, Brown LK, editors. Textbook for Midwives (13th ed). Edinburgh: Churchill Livingstone, 1999.

9. Bereck K. Aetiology of pressure sores. Clinics N America 1975; 10: 157.

10. Reichel S. Shearing forces as a factor in decubitus ulcer formation: an hypothesis. Medical Hypothesis 1958; 4(1): 37-9.

11. Collier M. Pressure sore development and prevention Hertfordshire: Wound Care Society, 1995.

12. Torrence C. Pressure sores: aetiology, treatment and prevention London: Croom Helm, 1983.

13. Flanagan M. Pressure sore risk. J Wound Care 1993; 2(4): 215-8.

14. Cutting KF. The causes and prevention of macerated skin. J Wound Care 1999; 8(4): 200-1.

15. Callum N, Deeks J, Sheldon TA, Song F, Fletcher W. Beds and mattresses and cushions for pressure sore prevention and treatment. J Tissue Viability 1999; 9(4): 138.

16. Collier M. Pressure reducing mattresses. J Wound Care 1996; 5(5): 207-11.

17. Gosnell J. Pressure risk assessment: part II: analysis of risk factors. Decubitus 1988; 2(3): 40-3.

18. Aitkenhead AR, Smith G. Textbook of anaesthesia. London: Churchill Livingstone, 1996.

19. Offori EM, Popham P. Decubitus ulcers after instituting epidural analgesia for pain relief in labour. Anaesthesia 2000; 55: 194.




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