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Establishing nutritional guidelines for critically ill patients: Part 1

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Marie E. Riley, RN, Dip Adult Critical Care.

Staff Nurse, Cardiothoracic Intensive Care Unit, The General Infirmary at Leeds, Leeds

Providing nutrition to hospitalised patients has long been acknowledged as an important component of their care. This paper reviews the author's attempts to provide evidence-based guidelines for such care within the intensive care environment (Box 1).
Providing nutrition to hospitalised patients has long been acknowledged as an important component of their care. This paper reviews the author's attempts to provide evidence-based guidelines for such care within the intensive care environment (Box 1).

Information was retrieved from several sources, beginning with an extensive literature review. Key words such as 'nutrition', 'enteral feeding', 'naso-gastric tubes' and 'prokinetics' were entered into Medline and Cinahl databases. Similar search terms were used on the Internet and on a variety of health-related websites. Surveys within the author's working environment have outlined the current situation, while interdisciplinary discussion with the Trust-wide Enteral Nutrition Group (TWENG) of the Leeds Teaching Hospitals NHS Trust and contact with staff in other ICUs allowed a more global view.

While the guidelines relate to patients requiring intensive care after cardiac surgery, with some adaptation they are easily applicable to a variety of areas from hospital to the home. This paper will discuss the evidence used to produce the guidelines and the changes in practice required in implementing them fully.

While dietetic involvement is vital, most patients begin feeding regimens before a full review. The guidelines are therefore nurse-led, built around a feeding algorithm adapted from work by the American Society for Parenteral and Enteral Nutrition (ASPEN, 1993) and agreed with the dietetic department at the Leeds General Infirmary (Figure 1). Formulae may well be changed when a full dietetic review is undertaken.

In order to identify the basis for nutritional intervention certain questions need to be answered. These are the same whatever the area of nursing:

- What is the incidence and effect of malnutrition?

- How does this relate to your own patient population?

- Is nutritional support required?

- Is there an optimal route for nutritional support?

- What are the advantages and disadvantages of a prescribed protocol?

Incidence and effects of malnutrition
It is evident from the literature that malnutrition is a common problem in the hospitalised patient (Lennard-Jones et al, 1995; Norton, 1996; Young, 1988). Overall, incidence is cited at around 40% (Lennard-Jones et al, 1995; Norton, 1996; Reilly et al, 1995). This malnutrition often has serious implications (Norton, 1996) (Box 2). Ultimately, the prevalence of minor complications is doubled, major complications trebled, hospital stay protracted and mortality increased four-fold (Dickerson, 1986; Holmes, 1998; Norton, 1996).

Risk assessment
Many authors suggest that the consequences of malnutrition defined in Box 2 develop subtly and that warning signs are often missed (Reilly et al, 1995; Norton, 1996; Sizer, 1996), thereby highlighting the need for adequate assessment. Variations on the components of assessment considered appropriate exist. These include body mass index (BMI), weight loss (amount and duration), food intake and the ability to retain food. The inability to eat independently (Norton, 1996), height, weight and biochemical factors, including alterations in serum albumin and vitamin levels, should also be taken into consideration (TWENG, 2001; Verity, 1996). Stress factors ranging from minor surgery to multiple trauma exacerbate any problems (Reilly et al, 1995).

While a full and accurate assessment of dietary need will require the involvement of a dietitian, this is not always possible 24 hours a day or seven days a week. It is therefore suggested that the nurse can identify those patients in whom, because of their presenting condition or treatment, at least some form of intervention is necessary (Box 1, Guideline 1). A risk-assessment tool is vital and, in line with recommendations from Sizer (1996), should be valid for the target group. There are many factors influential in limiting nutritional intake (Holmes, 1998; McLaren, 1998; Norton, 1996). These form the basis for any questions used to identify risk. Examples for the critically ill include:

- Is the patient ventilated?

- Do you consider that the patient will be extubated within the next six hours?

If self-ventilating:

- Are any of the following being used: continuous positive airways pressure (CPAP); spontaneous biphasic positive airways pressure (BiPAP); high- flow oxygen therapy (Hi Flow)?

- Is a facemask/nasal cannulae in use?

- Does the oxygen saturation (SaO2) fall below 90% if the mask is off for five minutes?

- Is the patient sedated and with what drug at what dosage?

- Is there any nausea and/or vomiting?

- Is there any physical disability, for example limb weakness/dysphagia?

- Is there any reduction in wound healing?

Timing and method of intervention
Having shown that the detrimental effects of malnutrition are multiple (Box 2) decisions have to be made about the timing and type of any intervention. Bower et al (1995) identify the ability of nutrition to support immune function while correcting nutritional deficits. Chan et al (1999) give unsupported and uncorroborated advice that enteral nutrition does not improve outcome if used for less than a week. However, McClave et al (1999) suggest that even two days of non-feeding can have deleterious effects that are not easily corrected by re-feeding. Finally, Bradley (2001) identifies an improved survival in those patients receiving early enteral feeding.

It has become routine to use the enteral feeding route in patients who have an intact and functioning gastrointestinal tract but have an inadequate oral intake. Enteral feeding helps to maintain the structural and functional integrity of the gastrointestinal tract (ASPEN, 1993), is easy and safe to use and relatively cheap when compared to total parenteral nutrition (TPN). Indeed, Coulston (2000) identifies it as the preferred route, with Frost et al (1997) suggesting that failure to use this route preferentially is tantamount to failure to give high-quality care.

Heyland et al (1995) identified differences in the time-scale for starting enteral feeding and this appears to be borne out by differing practices across the units here in Leeds. Indeed, variations existed within the author's own clinical environment. Guideline 2 (Box 1) aims to prevent such discrepancies in care and is underpinned by the following:

- It is usually possible on the first day after surgery to identify those patients who will remain ventilated

- There may be a significant group of patients who, when extubated, have very limited nutritional intake. This could be due to loss of appetite but is often related to dyspnoea and the type of associated oxygen therapy, for example BiPAP or CPAP

- Some patients who require re-admission to the unit with respiratory or cardiac insufficiency have been deteriorating over a significant period and had very limited nutritional intake in the interim.

The ethical setting
There are no easy answers to the ethical and legal issues surrounding nutrition. The provision of quality nutritional care is underpinned by the need to consider and meet with its ethical and legal requirements. While oral nutrition is defined as basic care, enteral and parenteral interventions are considered to be treatments (MacFie, 2000). Basic care is a right which can never be denied to a patient who does not refuse it; whereas treatment is not always compulsory (MacFie, 2000). The main areas for consideration include:

- Consent should be obtained (Glover, 1999), including reasonable explanation of the procedures involved and their material risks

- Advance directives. In some cases, a patient may have considered his or her options in the event of untoward complications and, having done so, made an advance directive for these situations. The BMA (1995) advises that there are both advantages and disadvantages to making treatment decisions in advance but suggest that competent, informed adults have that inalienable right. Some trusts are investigating how such directives might be taken into account; their decisions could impact on future care

- Withdrawing/withholding treatment: the BMA (1999) identify no difference between the two alternatives but suggest that it is immoral to withhold merely to avoid the decision to withdraw.

The consideration of these problems is a multidisciplinary task with no one professional group holding the monopoly on decision-making (Goodhall, 1997).

- Part 2 of this paper will appear in the July edition of Professional Nurse.

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