Valerie Irving, BA (Hons), RN, RM, ENB 405, 997.
Sister/Team Leader, Neonatal Unit, Liverpool Women's Hospital, LiverpoolInformation on the following pages is brought to you as a joint initiative between Professional Nurse and the Journal of Wound Care. This will be a regular feature in each issue of Professional Nurse - offering a selection of the latest evidence-based practice in tissue viability. This paper is based on an article first published in Journal of Wound Care, July 2001 (10: 7, 253-256). To subscribe to the Journal of Wound Care, call 01858-438847 (£37 personal). Due to the lack of research-based evidence on caring for pre-term infants, many ritualistic practices, such as the use of liquid baby bath, barrier products for the nappy area and iodine or alcohol-based antimicrobials and cleansing agents, are still undertaken by nurses working in this area. It is therefore important to understand how the skin of a pre-term infant develops and will react to the use of certain agents.
|Information on the following pages is brought to you as a joint initiative between Professional Nurse and the Journal of Wound Care. This will be a regular feature in each issue of Professional Nurse - offering a selection of the latest evidence-based practice in tissue viability. This paper is based on an article first published in Journal of Wound Care, July 2001 (10: 7, 253-256). To subscribe to the Journal of Wound Care, call 01858-438847 (£37 personal).|
Due to the lack of research-based evidence on caring for pre-term infants, many ritualistic practices, such as the use of liquid baby bath, barrier products for the nappy area and iodine or alcohol-based antimicrobials and cleansing agents, are still undertaken by nurses working in this area. It is therefore important to understand how the skin of a pre-term infant develops and will react to the use of certain agents.
Development of the skin
By 24 weeks' gestation the epidermis has developed the intermediate layers (stratum granulosum, stratum spinosum and stratum basale) but the stratum corneum is still underdeveloped. This means that the barrier function is minimal at this stage. At about 30 weeks' gestation, the epidermis has all the layers of the adult epidermis, but is still immature. The stratum corneum is still only two- to-three cell layers' thick and remains a poor barrier. The skin is considered to be functionally mature by 33 weeks' gestation, when the epidermis is fully keratinised and becomes an effective barrier. Although the dermal/epidermal junction is becoming stronger, it is still fragile and easily damaged (Rudy, 1991).
In normal pregnancy, by 40 weeks' gestation, the stratum corneum is about 30 cell layers' thick, providing barrier function, although the epidermal and dermal layers are only up to 60% as thick. Regardless of gestation, two to three weeks after birth, the rapid maturation of the epidermis means the skin is similar to that of a term infant. However, during this time potential for trauma is great.
Appearance of pre-term skin
At 24 weeks' gestation the skin is red because of the lack of subcutaneous fat, the dermis lies directly on top of the muscle tissue, and prominent veins are easily seen due to the thin epidermis. The lack of keratinisation of the poorly developed stratum corneum causes high trans-epidermal water loss, giving the skin a moist, shiny appearance and a gelatinous feel.
Poor barrier function
Due to poor barrier function there is high trans-epidermal water loss. During a 24-hour period an infant at 26 weeks' gestation can lose up to 110ml of water through the skin, leading to fluid and electrolyte imbalance if not correctly managed. High trans-epidermal water loss can lead to instability of the core temperature and, because the skin surface is constantly damp, the potential for evaporative heat loss is high.
Infants should be nursed in a servo-controlled environment with humidity at 85-90% in order to maintain warmth and preserve the integrity of the skin. Over two to three weeks the humidity can be reduced to 40% and then discontinued. Radiant over-head heaters are associated with excessive levels of trans-epidermal water loss and overheating so are being phased out.
Absorption of chemicals
The skin has an increased potential to absorb applied chemicals. Cleansing agents containing iodine have been shown to cause a transient hypothyroidism (Linden et al, 1997), while hexachlorophane damages the central nervous system (Powell et al, 1973). Prolonged contact with alcohol-based products can cause second- and third-degree burns on the skin of very pre-term infants (Schick and Milstein, 1981). Watkins and Keogh (1992) found that even a few short exposures to a swab pre-soaked in isopropyl alcohol could cause full-thickness skin loss in an infant born at 24 weeks.
Skin preparations should be aqueous-based and exposure time limited. Aqueous chlorhexidine (Seton) is a broad-spectrum antiseptic, more effective than povidone-iodine or alcohol in reducing bacterial activity (Maki et al, 1991), and not apparently toxic (Rutter, 1987).
The skin pH of babies born at term is 6.4, falling to 4.9 over three to four days, as the body develops a protective acid mantle. This can take up to three weeks in the pre-term infant. Alkaline soap or baby bath alter the pH of the skin for up to one hour after use in term infants and longer in the pre-term infant, influencing the colonisation of bacterial flora present on the skin. These products also contain perfumes and dyes, so should not be used at all in the first two to three weeks of life in a pre-term infant. Creams and emollients also contain preservatives and perfumes, so routine use is not recommended. They should be used only when cracking of the skin is likely to occur.
Increased risk of trauma
Three types of skin trauma are associated with the very pre-term infant:
Epidermal stripping - This occurs on removal of adhesive products if the bond between the product and the epidermis is stronger than the bond between the epidermis and the dermis (Figure 1). It causes a break in the limited protective barrier, increasing susceptibility to local or systemic infection and absorption of chemicals. Therefore, bonding agents should be avoided (NANN, 1997) as should adhesive removal products that contain alcohol.
Pectin-based hydrocolloid products such as DuoDerm (ConvaTec) provide a barrier for anchoring tape used to secure catheters and monitoring probes. They can be left in place when the probe or tape requires re-siting, then reused. However, if removed too soon or incorrectly, they too have the potential to cause damage.
Intravenous cannulae should be secured using clear sterile film dressings such as Opsite IV 3000 (Smith and Nephew) or Tegaderm (3M), as there must be unobstructed visibility at the site of insertion for the detection of infiltration, infection, displacement or extravasation.
Application of Cavilon Barrier Film (3M) on the skin before the use of the Opsite IV 3000 has been shown to be beneficial, although there have been no studies into the absorption rate and possible effects of this product in this patient group (Irving, 2001).
Epidermal stripping can occur following unnecessary force during handling and tissue damage caused by rings with stones, or thick wedding bands. Shearing injuries can occur in the same manner as in adults, so blankets rolls, baby nests and other products are used to provide boundaries to reduce this risk, rather than for positional care.
Pressure necrosis - The dermis of the pre-term infant has reduced amounts of collagen and elastin fibres as well as a high water content (Lund, 1999). This tissue oedema can reduce the blood flow to the epidermis and increase the risk of pressure-related necrotic injuries. Although typical pressure ulcers are not often found in the pre-term infant due to the large surface area-to-weight ratio, pressure-relieving overlays can be used on top of mattresses to increase comfort, while large quantities of Gamgee Tissue help provide a soft pressure-reducing surface.
Pressure injuries can be caused by monitoring equipment, such as saturation probes (Figure 2). Even if re-sited frequently, the pressure generated can quickly cause skin damage in the very pre-term, hypovolaemic, hypotensive, unstable or sedated infant.
Ear lobes are susceptible to damage, therefore hats worn to reduce heat loss or to secure endotracheal tubes should not be tied tightly (Figure 3). They should also have enough stretch to accommodate oedema, which often occurs a few days after birth.
Nasal intubation cannula can cause damage if incorrectly sized or positioned. Pressure from splints or drainage catheters can lead to necrosis, so position changes in which the tubing is supported away from the body and careful checking of vulnerable sites are necessary.
Extravasation injury - This is serious and potentially disfiguring, occurring when intravenous fluids or medication leak into the surrounding tissue (Figure 4). Solutions containing more than 10% dextrose, calcium gluconate, potassium chloride and sodium bicarbonate can all cause tissue damage due to the effects on the tissue cells, the local blood vessels and the added constrictive pressure caused by the build up of the infused fluid in a contained space.
If extravasion occurs, Gault (1993) recommends the use of hyaluronidase, an enzyme which temporarily breaks down the connective tissue, allowing the extravasated fluid to be flushed out through multiple 'stab' wounds surrounding the injury. This will give good results if undertaken within an hour of the injury occurring, but again lacks research-based evidence in this patient group to support it.
Many neonatal units choose to treat extravasion injuries (Malloy-McDonald, 1995). Irving et al (1996) explored the benefits of using DuoDerm (ConvaTec), which provides a moist wound environment, absorbs moderate levels of exudate, allows movement at the joints, has an extended wear time and, most importantly, does not cause trauma on removal (Irving et al, 1996) (Figure 5).
Thomas et al (1987) discussed treating extravasion with Intrasite gel (Smith and Nephew) in a bag. As well as reducing scarring, the wound was visible at all times, the surface was kept moist even in the high ambient temperatures of an incubator, and the gel is easy to apply and relatively cheap. However, as there are no commercially available plastic bags in which to treat the limb, urine collecting bags or other products are adapted, reducing their sterility and, as the bag has to be secured on to an already compromised limb, the risk of further skin damage due to removal of the adhesive products increases.
Few wound-care products are specifically evaluated for use with pre-term infants and few neonatal units have devised suitable documentation for recording iatrogenic injuries. However, wound assessment, along with a clinical rationale for the use of products, is as important for these tiny patients as for any other patient group.
The super-absorbent, gel-cored disposable nappies used in most neonatal units have eliminated the potential for contact dermatitis caused by residual laundry products. Because of the absorbency of these nappies, and the potential risk of chemical absorption, barrier products are considered unnecessary. In practice, however, infants can still develop rashes due to contact with urine, which changes the pH of the skin and allows proliferation of bacteria. Commercially available products such as Sudocrem (Tosara) or zinc and castor oil can be used, although there is a lack of any specific research to support it, while those made up by the hospital pharmacy department are subjectively applied, so there is no standard treatment to evaluate.
Loose stools or diarrhoea can quickly break down the skin. Most creams and ointments will not adhere to broken or bleeding tissue. Orabase ointment (ConvaTec), used in stoma care, is effective in protecting broken and bleeding skin.
Management of tissue viability in the pre-term infant is complex and frustrating. There are no national or regional guidelines to follow and although interest is growing it appears to be left to individual practitioners to lead the way forward.
There is a shortage of specifically trained nurses in the area and staff come from general, paediatric or midwifery backgrounds, each with their own unique skills and expertise, but also with their own priorities. Although the number of infants admitted to neonatal units may be limited - on average 10% of total live births - the extended period of hospitalisation that many require can stretch the expertise of even the most experienced staff.
Education of staff varies, with the content of post-registration courses reflecting the needs of the individual local unit from which they have been recruited. Skin care and tissue viability are not part of the compulsory curriculum for diploma- or degree-level neonatal courses. And there is no standardisation of equipment, even within a single neonatal unit.
The development of benchmarking groups to decide 'best practice' and set standards of care is one way forward and may help to build up a network of knowledge and expertise. Also more research posts for nurses and funding should be made available to ensure that every unit is giving the best research-based care possible. Finally, ritualistic practices that are not in the infant's best interests must be abandoned.
Gault, D.T. (1993)Extravasation injuries. British Journal of Plastic Surgery 46: 91-96.
Irving, V., Young, T., Atkinson, J. (1996)Wound management in neonates. Nursing Times Know How Supplement 96: 46.
Irving, V. (2001)Reducing the risk of epidermal stripping in the neonatal population. Journal of Neonatal Nursing 7: 1, 5-8.
Linden, N., Davidovitch, N., Reichman, et al. (1997)Topical iodine-containing antiseptics and subclinical hypothyroidism in pre-term infants Journal of Pediatrics 131: 3, 434-439.
Lund, C. (1999)Prevention and management of infant skin breakdown. Nursing Clinics in North America 34: 4, 907-920.
Maki, D., Ringer, M, Alvarado, C. (1991)Prospective randomised trial of povidone-iodine, alcohol and chlorhexidine for prevention of infection associated with central venous and arterial catheters. Lancet 338: 339-343.
Malloy-McDonald, M. (1995)Skin care for high-risk neonates. Journal of Wound, Ostomy and Continence Nursing 22: 4, 177-182.
National Association of Neonatal Nurses. (1997)Neonatal Skin Care: Guidelines for Practice. Glenview, Ill: NANN.
Powell, H., Swarner, O., Gluck, L., Lampert, P. (1973)Hexachlorophene myelinopathy in premature infants. Journal of Pediatrics 82: 6, 976-981.
Rudy, J. (1991)From conception to birth: the development of skin and nursing care implications. Dermatology Nursing 3: 6, 381-390.
Rutter, N. (1987)Drug absorption through the skin: a mixed blessing. Archives of Disease in Childhood 62: 220-221.
Schick, J., Milstein, J. (1981)Burn hazard of isopropyl alcohol in the neonate. Pediatrics 68: 4, 587-588.
Thomas, S., Rowe, H.N., Keats, J., Morgan, R.J.H. (1987)A new approach to the management of extravasation injury in neonates. Pharmacy Journal 239: 584-585.
Watkins, A, Keogh, E.J. (1992)Alcohol burns in the neonate. Journal of Paediatric Health 28: 306-308.