VOL: 101, ISSUE: 08, PAGE NO: 59
Susan MacQueen, MSc, RGN, RSCN, is clinical nurse specialist and lead clinician in infection control, Department of Microbiology, Great Ormond Street Hospital for Children, LondonSusan MacQueen, MSc, RGN, RSCN, is clinical nurse specialist and lead clinician in infection control, Department of Microbiology, Great Ormond Street Hospital for Children, London
Compliance with infection control guidelines, which includes ensuring effective hand hygiene, having optimal staffing levels, practising aseptic techniques and taking appropriate care of devices, can lower health care-associated infections. Allen and Forde-Jones (1990) indicated that 10-20 per cent of nosocomial infections in the paediatric population are bloodstream-related. A study on the efficacy of nosocomial infection control (Haley, 1985) demonstrated that hospitals with a more effective infection surveillance and control programme could reduce their bacteraemia rates by 15-35 per cent.
Risk factors in babies and infants
Young babies, especially neonates, are at high risk of infection owing to a number of factors (Table 1). Another risk factor is related to their skin flora, which will vary in individual babies according to certain environmental factors or procedures that have been undertaken, such as the following:
- The place of birth (in hospital or at home) - Aiello et al (2003) found differences in prevalence, bacterial composition and antimicrobial resistance of hand flora of hospital personnel compared with people at home. Staphylococci are the most common micro-organisms isolated from blood cultures in young children, and the number of different staff handling children can affect whether they acquire the hospital strains of the micro-organism;
- Nappy-wearing - this increases the distribution of coliforms (such as Escherichia coli and Klebsiella) on the skin;
- Hot, moist skin - pre-term infants are often nursed in high humidity in incubators to maintain their body heat, and such skin has a higher bacterial count (Blank and Oawes, 1958);
- Loss of skin integrity - although shaving the skin is not common in paediatric practice, it may be done if a scalp vein is to be used for venous access. The procedure may damage the skin, so increasing microbial colonisation and that of invading organisms during insertion of the intravenous cannula;
- Use of antibiotics - antibiotics alter the microbial flora and increase colonisation with more pathogenic strains of bacteria or fungi. Henderson (2000) indicated that alteration in the normal flora is a common event preceding cannula-site infection;
- Other sites of infection - urinary tract infection, for example, may increase the risk of infection via the bloodstream or by cross-contamination.
Bravery (1999) outlines the physiological differences between children and adults (Box 1).
Common intravenous insertion sites
When planning the site of an intravenous insertion, the reason for inserting the line, and the baby's age and stage of development, should be taken into consideration. Non-dominant limbs should be used to allow the child to carry out normal activities such as thumb-sucking (Box 2).
Using steel needles (butterfly needles) for the administration of fluids and medication should be avoided, as they may cause tissue necrosis (Healthcare Infection Control Practices Advisory Committee ((HICPAC)), 2002). A cannula should be selected according to the size of the child's vascular access and the intended use. Peripheral cannulae range in size from 26 gauge for neonates to 14 gauge for older children.
The volume of a paediatric-size tunnelled central venous catheter is about 1ml. However, adult catheters or implantable devices may be used in older children and the catheter cut to size during insertion, thus reducing its volume. This procedure must be recorded, as it has a bearing on calculating the volume of fluid required to flush the catheter following administration of the drugs. This can have implications for maintaining the child's fluid balance (see below).
The choice of the chemical used to decontaminate the skin must be carefully considered, as the surface area to body weight ratio is much greater in children than adults and is an important consideration in pre-term infants. The skin of babies born full term has a pH of 6.4, which reduces to 4.9 over a few days as the body develops its protective acid mantle - a natural antibacterial protection. This process can take up to three weeks in the pre-term infant (Irving, 2001).
Chemicals applied to the skin of pre-term infants are more likely to be absorbed through the skin than in adults, and the rate of absorption may increase if an occlusive dressing is used. Schick and Milstein (1981) reported that chemical burns can result from exposing infant skin to 70 per cent isopropyl alcohol, either in pads or direct solution. They recommend that 70 per cent isopropyl alcohol be used with extreme caution on severely premature infants.
Examples of transient hypothyroidism (caused by agents containing iodine) and damage to the central nervous system (caused by hexachlorophane) in neonates has been cited in the literature (Irving, 2001). The HICPAC guidelines (2002) indicate that there is no consensus on the use of chlorhexidine on babies under two months of age. However, Irving (2001) states that aqueous chlorhexidine is a broad-spectrum antiseptic and has been found to be safe on pre-term infants. Chlorhexidine 0.5 per cent in 70 per cent alcohol is commonly used with caution in clinical practice. The solution must dry before inserting the cannula, and any excess wiped away with sterile distilled water or saline.
Standard 5.8 of a document on standards from the RCN IV Therapy Forum states that a sterile dressing must be applied to cannula insertion sites (RCN, 2003). The HICPAC (2002) guidelines recommend covering the site with either sterile gauze or sterile, transparent, semi-permeable dressings. In neonates and infants it is essential to inspect the site regularly. A peripheral cannula should be secured with sterile tape, such as sterile skin closure strips, and the sterile dressing should be applied on top.
Cannulae in babies and infants can become dislodged easily, causing infiltration, extravasation (leakage and spread of blood or fluid from blood vessels into surrounding tissue), and infection. Neonates are at risk of extravasation injuries as they often receive high concentrations of glucose and calcium for growth and maintenance of normal levels. These can cause venous irritation and thrombophlebitis. The RCN document on standards (RCN, 2003) points out that it is essential that policies are in place for urgent management of extravasation injuries (Standard 9.3). The cannula site should be inspected frequently (at least hourly) and always before injecting any solutions. Phlebitis should be documented using a uniform standard scale (Standard 9.1) (RCN, 2003).
The limb must be splinted correctly in order to reduce the risk of trauma or infection. It is important to follow the manufacturer's instructions when using a splint. Furthermore, care must be taken not to secure the limb too tightly, as this may cause serious nerve or circulatory damage.
Using equipment that is not designed for this purpose can result in serious sepsis. For example, Rhizopus microsporus (an environmental fungus) has been found in wooden tongue depressors (often a convenient splint size for small limbs) and has caused death and limb amputation of a number of neonates (Mitchel et al, 1996; Holzel et al, 1998). A hazard warning was issued by the former Medical Devices Agency (1996) on this subject, after which practice around the country on limb splints was changed.
A clean bandage can be used to wrap round a splinted limb to deter the child from touching or sucking it. Cotton bandages with loose cotton fibres should not be used, as they can be eaten, and fibres can become wrapped round small fingers and toes, restricting circulation and causing necrosis.
Replacement of equipment
The HICPAC (2002) guidelines recommend that all cannulae should be removed as early as possible. Peripheral venous cannulae in children can be left in place until intravenous therapy is complete, unless complications occur or the cannula has not been placed aseptically; in an emergency, for example. If possible, umbilical arterial catheters should remain in place for no more than five days. Umbilical venous catheters can be used up to 14 days. The following are guidelines for handling equipment in order to reduce infection risks:
- Change administration sets and connections every 72 hours unless cannula-related infection is suspected (HICPAC, 2002);
- Change administration sets for blood or blood product administration or lipid emulsions after completion of the infusion or within 24 hours;
- Always follow the manufacturer's instructions;
- Routine parenteral fluids should be prepared in the pharmacy in a laminar-flow hood;
- Use single-dose vials for parenteral additives or medication. Although drug wastage occurs in paediatric care because of variation in doses, the re-use of single dose files is strongly discouraged, as sterility is compromised once the seal on a vial has been opened;
- Do not use in-line filters for infection prevention purposes, although they can be used to filter particulate matter (HICPAC, 2002).
Observations for signs of infection
Baseline observations of weight, height, blood pressure, temperature, pulse and respiration should be taken where possible before embarking on intravenous therapy. This helps give a comparison should infection occur. In neonates, the body temperature may fluctuate and there may be periods of bradycardia or apnoea. Pyrexia is common in children, and a full septic screen should be undertaken if infection is suspected in those with an intravenous device. Hypotension is a late sign of shock.
Maintaining the cannula
Chemical and mechanical phlebitis (inflammation of the wall of the vein) as a consequence of peripheral therapy can occur in children. Children are at risk of chemical phlebitis, as their veins are smaller than those of adults, and they are subject to reduced blood flow around the device (Bravery, 1999). The addition of an extension set can help the practitioner manipulate the administration set for the delivery of drugs, and this can help to reduce mechanical phlebitis.
Displacement volumes must be accounted for when administering drugs to children so as to avoid incorrect doses. Cannulae should be flushed with sodium chloride 0.9 per cent or other compatible solutions (Bravery, 1999) after the drug has been given. Small volumes of fluid used to flush the line in neonates or those with cardiac or renal insufficiency may cause over-infusion, resulting in cardiac and pulmonary failure.
It is recommended that a 10ml syringe be used for procedures that test the patency of the intravenous cannula. Smaller syringes will exert pressures greater than 25 pounds per square inch, which may precipitate cannula rupture, cannula embolus or septum rupture in multiple lumen catheters (Bravery, 1999).
Documentation of care
An electronic intravenous infusion device with over 95 per cent accuracy should be used to control infusion delivery. It should include a variable pressure facility that the operator can set to account for the length and diameter of the administration set, the viscosity of the solution and the flow rate (Bravery, 1999).
It is essential that accurate hourly records are kept of all fluid intake (intravenous solutions, drugs and flushing solutions) and of fluid output (blood samples - especially in babies less than 10kg - body fluid aspirations, urine, stool, vomit or other fluid drainage). This will avoid complications of blood loss, dehydration or overloading the circulatory system, which may increase the risk of infection or other complications.
Winning Ways, a document from the Department of Health (2003), indicates that the insertion and removal date of all intravenous cannulae must be recorded in the child's clinical notes. Lawrence (1994) found that by performing a central venous line audit and targeting specific processes such as hand-washing and the type of teaching programme (it should be structured), the rate of line infections was reduced.
Parental involvement and education
Parents or carers can help in the success of intravenous therapy in children. Holding children is necessary for successful insertion of a device or to gain access to an intravenous device. A parent may help if he/she feels confident, but should be seen by the child as a comfort and therefore should not be coerced into assisting. Topical agents to reduce pain should be used routinely in paediatric care or until the child no longer feels the need for them.
Despite the complexity of intravenous therapy, children can be nursed at home by their parents once they have been taught how to prevent infection by using aseptic techniques and have been made aware of the risk factors for complications. There are fewer cannula-related infective episodes if children are nursed at home, where there are fewer people handling the line. It is therefore important to standardise practice and ensure that nurses and doctors are competent, so that the child and his/her parents have confidence in them.
The legal context for consent to treatment applies when parents undertake care at home. They must be willing to undertake the care, be given time to learn with a formalised teaching programme and be given adequate written information, including named people to access 24 hours a day if they feel this is needed.
The condition of children having intravenous therapy can deteriorate rapidly if complications occur. Nurses caring for these patients must, therefore, be vigilant at all times, so that early signs of infection and other complications can be detected, investigated and corrected. n