Stomas and nutrition

Chapter 3.17
Stomas and nutrition

Alison Culkin

St Mark’s Hospital, Harrow, UK

A stoma (from the Greek word meaning ‘mouth’) is an opening, connecting a portion of the GI tract to the outside of the body. Intestinal effluent passes out of the stoma and is collected in an external bag attached to the skin. An ileostomy or colostomy is created when part of the small intestine (ileum) or large intestine (colon) is brought out onto the surface of the abdomen, respectively. A stoma may be temporary or permanent depending on the underlying condition. Several conditions may necessitate the formation of a stoma and some are listed in Table 3.17.1.

Table 3.17.1 Conditions which may require stoma formation

Colostomy	Ileostomy
Diverticulitis	Crohn’s disease
Anal stenosis	Ulcerative colitis
Faecal incontinence	Familial adenomatous polyposis
Pelvic tumours	Hirschsprung’s disease
Colorectal cancer	Colorectal cancer
Abdominal trauma	Abdominal trauma
Perianal sepsis	Bowel obstruction
Pseudomembranous enterocolitis	Ischaemic bowel
Radiation enteritis	Radiation enteritis

There are three types of colostomy [1].

Loop colostomy – often performed in an emergency as a temporary procedure. The colon is sutured to the abdomen and two openings are created in the one stoma: one for intestinal effluent and the other for mucus naturally secreted by the GI tract.
End colostomy – known as a Hartmann’s procedure, named after the surgeon who first described it, this involves the removal of the rectosigmoid colon with closure of the rectal stump and formation of an end colostomy.
Double barrel colostomy – the colon is severed and both ends are brought out onto the abdomen with only the proximal stoma functioning.

There are three types of ileostomy [1].

Temporary or loop ileostomy – involves a loop of the small intestine being brought through the skin, and the colon and rectum remain in situ, often performed as the first stage in the surgical construction of an ileo-anal pouch to prevent intestinal effluent entering the pouch until adequate healing has occurred. The ileostomy is then reversed, usually after 8–10 weeks.
End ileostomy – this is often a permanent option where the colon and rectum are removed and the end of the small intestine is brought through the skin.
Continent ileostomy – similar to an end ileostomy but without the need to attach an external bag as a pouch is created internally utilising the end of the small intestine. The stoma is connected to a valve implanted into the skin and can be emptied using a catheter. This option has mainly been replaced by the ileo-anal pouch although it is still performed in a small minority of patients unable to have this operation.

3.17.1 Preoperative nutritional status

The nutritional status of patients requiring stoma formation will be affected by their underlying medical condition and concurrent treatment such as radiotherapy and chemotherapy. Patients presenting to the outpatient department should be screened for undernutrition using a validated tool, as undernutrition is known to adversely affect clinical outcome. Garth et al. (2010) reported that undernourished GI cancer patients identified using subjective global assessment (SGA) had a longer length of stay (P<0.05) and a greater risk of complications (P<0.01) compared to well-nourished patients [2]. There is currently no agreed international definition of undernutrition and therefore comparisons between centres are problematic. The incidence of undernutrition in colorectal patients varies from 20% to 50% [2–4] depending on the criteria used.

A study in patients with colorectal cancer aimed to examine the associations between different techniques used to assess risk of undernutrition with survival [4]. The risk of undernutrition was assessed using SGA and the nutritional risk screening (NRS-2002) as recommended by the European Society of Parenteral and Enteral Nutrition (ESPEN). Sarcopenia was assessed using computed tomography (CT) scans by calculating the muscle mass cross-sectional area (cm²). The presence of cachexia was assessed using the Cancer Cachexia Study Group (CCSG) criteria:

weight loss of ≥10%
energy intake of ≤1500 kcal/day
C-reactive protein (CRP) ≥10 mg/L.

The incidence of undernutrition was 34% (SGA) with 42% nutritionally at risk (NRS-2002) and 39% identified as sarcopenic. The authors found that 22% with cachexia (CCSG) had a shorter survival (P=0.005). There was poor agreement between methods but the CCSG cachexia score was the best prognostic factor regarding survival [4].

An international consensus on the definition and classification of cancer cachexia has recently been agreed and includes these parameters [5]:

Body Mass Index (BMI) <20 kg/m² plus weight loss of >2%
weight loss of >5% in 6 months
sarcopenia.

It is hoped that after validation, this work will benefit the design of clinical trials and future clinical management.

Patients with inflammatory bowel disease (IBD) requiring surgery and formation of a stoma may be at high risk of undernutrition due to the symptoms associated with acute disease. Weight loss is common and has been estimated to occur in 70–80% of patients during hospital admission and in 20–40% of outpatients [6]. Several studies had determined that patients with IBD are not identified as undernourished when assessed using standard criteria such as SGA or BMI. However, when more sophisticated body composition techniques including bio-impedance, skinfold and muscle circumference plus muscle function measures such as handgrip are used then patients have significant differences from healthy controls [6–8], indicating that standard screening is inadequate.

Guidelines for perioperative care in elective colorectal surgery have identified that a low BMI does not seem to be a risk factor for complications although the presence of sarcopenia is predictive [9]. In a study of 234 patients, 39% were sarcopenic and length of stay was longer (P=0.038), infection risk greater (P=0.025) and inpatient rehabilitation more common (P=0.024) [10]. Therefore screening tools that include BMI may not be sensitive enough to identify patients experiencing the initial stages of sarcopenia, especially those who are overweight and obese.

Micronutrient deficiencies including ferritin, zinc and vitamins B6, B12, D and carotene have been reported in IBD [8]. Therefore screening for deficiencies and appropriate supplementation are recommended perioperatively.

3.17.2 Perioperative nutrition and enhanced recovery after surgery

Patients identified as undernourished are likely to benefit from improvements in nutritional status although evidence in colorectal surgery is lacking. A Cochrane review identified three studies comparing oral and two studies comparing enteral nutrition with standard care and found no difference in complications, infections or length of stay when provided preoperatively [3]. Three trials comparing preoperative parenteral nutrition verses standard care demonstrated a reduction in major complications in undernourished patients (P=0.0048). A meta-analysis of six trials investigating the use of preoperative immune-enhancing formulae versus no or standard nutrition in patients undergoing GI surgery showed a reduction in postoperative (P=0.003) and infective complications (P=0.008) and length of stay (P=0.02). Systematic reviews and meta-analyses are only as good as the data available and the reviewers stated that although benefits in terms of outcome were demonstrated, significant bias was apparent which limits the generalisability to all patients undergoing surgery [3]. In addition, many of the trials were carried out before the implementation of the enhanced recovery after surgery (ERAS) programme and so the results need to be interpreted within the current surgical context.

The ERAS protocol aims to reduce surgical stress, maintain physiological function and encourage early mobilisation. The evidence-based protocol has dramatically altered the perioperative management of surgical patients, resulting in earlier recovery and reduced length of stay [9]. A systematic review and meta-analysis by Lewis et al. (2009) showed that perioperative fasting in GI surgery is no longer recommended [11] and patients are encouraged to eat up to 6 h before surgery and undergo carbohydrate loading by consuming 400 mL of carbohydrate-containing fluids up to 2 h before surgery. Immediately after recovery from anaesthesia, patients are encouraged to drink and on day one can eat normal food, often supplemented with oral nutritional supplements to meet requirements. If patients require nutritional support postoperatively then a polymeric formula is recommended as a study of 12 patients undergoing total colectomy found an elemental diet was not superior to a polymeric in terms of macronutrient and micronutrient absorption [12]. Another study by the same group performed in 16 patients with well-established ileostomies supported the recommendation of a polymeric formula [13].

Postoperative complications cause a prolonged length of hospital stay, resulting in increased healthcare cost. Factors contributing to reduced quality of life for patients include:

intra-abdominal sepsis which can be life threatening
inadequate stoma care which can cause excoriated skin
high intestinal losses resulting in dehydration and electrolyte disturbances
poor perioperative nutrition support resulting in undernutrition
immobility
depression.

All of the above increase the length of rehabilitation during which the patient is unable to return to work and/or family life and therefore all measures should be employed to minimise the risk of these complications [14].

3.17.3 Colostomy

Nutritional consequences of colostomy formation

Formation of a colostomy can occur at any location along the colon, but the most common placement is on the lower left side near the sigmoid where a majority of colon cancers occur. Other locations include the ascending, transverse and descending sections of the colon. The location of the stoma is important as this may affect the risk of complications experienced by the patient due to difficulties absorbing fluid and electrolytes. The formation of a colostomy has minimal impact on the digestion and absorption of fluid and nutrition and most patients will be able to resume a normal healthy diet based on national guidelines such as the ‘Eat Well Plate’ (UK) or ‘Eat Right’ (USA) and ‘Eating Well with Canada’s Food Guide’. Obesity and weight gain have been associated with stoma retraction and therefore maintaining a healthy BMI is important [15].

Dietary management of a colostomy

There are no clinical trials supporting the use of a particular diet after colostomy formation. Immediately after surgery, patients are normally advised to consume a diet low in non-starch polysaccharides (NSP) in order to minimise the risk of obstruction as surgery may result in GI oedema. After surgery, intestinal losses may be liquid and the prevention of dehydration is paramount. Patients will need to consume at least 1.5–2 L of fluid daily. After 6–8 weeks a normal healthy diet can be eaten with foods high in NSP being introduced slowly to assess the effect on GI function. The introduction of ERAS may reduce the requirement for this cautious approach in the future with patients returning to a normal diet much more quickly after laparoscopic versus traditional open surgery.

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