Enterocutaneous fistula (ECF) occurs when there is an abnormal communication between the gastrointestinal (GI) tract and the skin. It may be caused by disease processes such as Crohn's disease, or iatrogenic (Dastur et al, 2015). Between 75% and 85% of ECFs are iatrogenic, resulting from trauma related to surgery. When fistulae occur in the small bowel about half are from an anastomotic leak and half from inadvertent injury to the small bowel during dissection (Gribovskaja-Rupp and Melton, 2016).
Initial efforts to manage ECF require input from the multidisciplinary team as success of further definitive surgical treatment relies on the patient being in optimal physical and psychological condition. The management involves reducing fluid losses, providing nutrients with fluids and treating the underlying cause and sepsis. Early wound management from a nurse specialist in stoma care is critically important to minimise the effluent-associated skin damage (Adaba et al, 2017).
Minimising the risk factors prior to the initial surgery helps to reduce the incidence of anastomotic leak and sepsis occurring (Grainger et al, 2018).
Intestinal failure
ECF can result in intestinal failure (IF), which is often fatal if not managed properly (Adaba et al, 2017). This is when the gut function is reduced so far it falls below the minimum necessary for the absorption of macronutrients and/or water and electrolytes, such that intravenous supplementation is required to maintain health and/or growth (Pironi et al, 2015). IF can be classified into three types according to its onset, metabolic and expected outcome criteria (Grainger et al, 2018) (Table 1). Acute IF, which typically lasts from a few days to months, may arise from ECF, high-output stoma, small bowel dysfunction, postoperative ileus or bowel obstruction, whereas chronic IF can be attributed to short gut, gut bypass, small bowel motility disorders or chronic persistence of any acute intestinal aetiology (Adaba et al, 2017).
| Type | Description |
|---|---|
| 1 |
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| 2 |
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| 3 |
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If a patient does not have GI function after 5 days following surgery further investigation may be required, depending on their overall status. Clinical assessment and metabolic factors such as abnormal electrolytes should be reversed and a CT scan performed to rule out intra-abdominal sepsis or a leak. Early involvement of the nutritional team is beneficial to prevent malnutrition, thus reducing the risk of further deterioration of an already debilitated patient. Parenteral nutrition is generally indicated if the patient has failed to tolerate an adequate enteral diet for 5–7 days (Grainger et al, 2018).
Sepsis control
Early recognition and management of sepsis is important and should be managed according to local protocols (trust's sepsis bundle) with resuscitation and rapid commencement of the appropriate antibiotic. Identifying the source of the sepsis is a priority and any abscesses within the abdomen should be drained percutaneously. However, if collections are inaccessible or there is an anastomotic leak with peritonitis, radiology imaging-guided drainage may not be possible. For these patients an early return to surgery may be required. However, if it is more than 10 days after the original surgery the surgeon will find entering the peritoneal cavity challenging due to fibrotic adhesions therefore making the surgery technically very difficult. In these circumstances the minimum amount of surgery should be undertaken to enable adequate drainage of infection, resection of any perforation and then formation of stomas. Once acute sepsis and urgent conditions requiring interventions have been excluded and immediate nutrition addressed to stabilise the patient, further work up for reconstructive surgery becomes key (Box 1) (Grainger et al, 2018).
Once the patient has become stable the onset of infection may be less obvious with no evidence of pyrexia or rise in white cell count. This is because a chronic infection may manifest itself with difficulty in gaining weight, hypalbuminemia, hyponatremia and even jaundice. Spontaneous healing of a fistula is less likely in the presence of active infection and resolution of sepsis is fundamental for maintaining adequate nutrition (Grainger et al, 2018).
Once the patient has become stable the onset of infection may be less obvious with no evidence of pyrexia or rise in white cell count. This is because a chronic infection may manifest itself with difficulty in gaining weight, hypalbuminemia, hyponatremia and even jaundice. Spontaneous healing of a fistula is less likely in the presence of active infection and resolution of sepsis is fundamental for maintaining adequate nutrition (Grainger et al, 2018).
Management of enterostomy output
Enterostomy output can mostly be controlled with appropriate management involving restriction of fluids, dietary modification and medications (Adaba et al, 2017) (Table 2).
| Stage | Aim | Management |
|---|---|---|
| 1 | Check for causes |
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| 2 | Reduce fluid and electrolyte losses |
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| 3 | Ongoing management |
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Fluids and electrolytes
Management initially involves reducing fluid losses, which is done by restricting oral fluid intake and replacing with intravenous rehydration. Oral fluid intake may be restricted to 1000 ml hypotonic fluid and 1000 ml hypertonic fluid a day. If dietary and fluid restrictions fail to reduce output then patients may be put nil by mouth to assess gastric secretions. Hypotonic fluids should be avoided as they cause water and sodium to diffuse into the intestinal lumen resulting in increased intestinal losses (Adaba et al, 2018). Electrolyte solutions such as St Mark's solution can be given to replace electrolyte losses (Table 3) and oral magnesium when required (Nightingale, 2003).
| Component | Amount added to 1 litre water |
|---|---|
| Sodium chloride | 3.5 g |
| Sodium bicarbonate | 2.5 g |
| Glucose | 20.0 g |
Note: To be sipped throughout the day, with or without flavouring
Nutritional support
A complete nutritional assessment should be undertaken and the regimen tailored to the individual patient by route and quantity Enteral feeding is the route of choice in all patients with a functioning GI tract but may be limited due to the presence of inflammation, strictures, obstruction, radiation damage, short bowel and intestinal fistulas. However, enteral feeding not only reduces the complications from parenteral nutrition, it is also important for the psychological health of these patients (Grainger et al, 2018).
Parenteral nutrition tends to be the mainstay of nutrition for patients with IF but long-term complications include complications related to intravenous access and liver disease. In reality patients may need a combination of both enteral and parenteral nutrition depending on the degree of dysfunction of their GI tract. What is important is that they receive adequate nutrition to meet their metabolic needs to prepare them for reconstructive surgery. This process can take several months, preferably with nutritional support at home where patients can eat familiar food, mobilise more, feel psychologically normal and reduce the risk of healthcare-acquired infections. Input from a specialist nutrition support team is required to facilitate the transition of patients' care from hospital to home (Grainger et al, 2018).
Once it is clear that a fistula is established there is no evidence that oral intake will prevent healing. Eating is psychologically beneficial and frequent meals can enhance the number of calories absorbed (Grainger et al, 2018). Efforts should be focused on implementing a high-calorie, low-fibre diet as a low-fibre diet passes slowly through the small bowel, thereby increasing nutrient absorption (Adaba et al, 2017).
Pharmacotherapy
Medications may be used to reduce gut secretions and reduce ECF output. Antidiarrheal medications such as loperamide and codeine phosphate can be given to reduce bowel motility and are often used in high doses (see Table 2). They should be administered prior to meals for optimal effect. Antisecretory medications such as proton pump inhibitors, histamine blockers (H2 antagonists) and somastostatin analogue (octreotide) may be added in (Adaba et al, 2017).
It is not uncommon for patients with IF and ECF to become dependent on both opioid and non-opioid analgesics. As analgesia administered orally may not be absorbed in patients with short gut or obstruction and intravenous access can be difficult, skin patches can provide more effective pain relief. Involvement of a pain team is advised together with access to non-pharmacological techniques such as distraction and a psychologist or psychiatrist with an understanding of addiction (Grainger et al, 2018)
Wound management of enterocutaneous fistula
Perhaps one of the most challenging and resource demanding aspects of ECF management is local control of the effluent (Gribovskaja-Rupp and Melton, 2016). As the inability to contain the fistula can be a source of morbidity for the patient, causing pain and severe discomfort from moisture-related skin damage when leakages occur, the skill and support of the specialist stoma care nurse is required (Grainger et al, 2018). The aim with management is therefore is to devise and agree a plan of care with the patient to contain the faecal effluent, prevent skin breakdown and provide comfort (Association of Stoma Care Nurses (ASCN), 2016). Practically, this means providing a leak-proof appliance that lasts for a minimum of 24 hours.
There are a variety of specially designed appliances available to use to manage fistula although some smaller ones can be contained effectively within a stoma appliance. All fistula appliances have drainable ports to attach drainage bags and are often used in conjunction with other ostomy products such as skin protector wipes, paste and washers to help the patient to obtain a satisfactory seal and minimise leakages. High-output fistulas are the most challenging to manage, sometimes taking up to 1.5 hours to change for a particularly complex one. However, there are some principles that should be followed (Box 2) and devising a photographic care plan can be helpful for staff to ensure that care remains consistent (ASCN, 2016) (Box 3).
Careful assessment of the contaminated wound is essential if a satisfactory system is to be found. The size of the fistula and wound bed (Figure 4) and the type, amount and consistency of the output needs assessing to assist with choosing the correct type and size of appliance to be used. The surrounding skin needs assessing to identify skin creases, dips and folds as these need packing out using a variety of products in order to establish a flat platform on which to fix the appliance. It is often assumed that having faecal fluid washing over a wound bed will lead to infection and further erosion of the wound. However, in the author's experience in practice this does not happen and the contaminated wound continues to heal. Although the mechanism is poorly understood it may be that faecal fluid does not provide as hostile an environment as previously thought or alternatively providing the wound with a warm moist environment (as occurs in an appliance) is the most important factor to promote wound healing.
In addition, the patient and ideally their family need to be taught how to self-care ready for discharge home and complex discharge arrangements need to be co-ordinated (Box 4). District nurses may be required to assist or manage changes in the community and early follow up from the local stoma care nurse is essential as problems with the appliance need to be anticipated and systems modified as patients become more mobile at home.
New wound management system
Negative pressure therapy is a technique whereby a vacuum dressing is used to promote wound healing. As it is becoming commonplace in managing acute or chronic wounds, it is not surprising that it is also becoming an option for the management of ECF (Gribovskaja-Rupp and Melton, 2016) as it can effectively contain the effluent, protect the surrounding skin and decrease the frequency of bag changes to one to two times a week.
To apply the dressing, the surrounding skin is first protected by a skin barrier followed by the application of a transparent film. A foam filler is then cut and shaped to fit to the contours of a wound bed (leaving the visible portion of fistulated bowel exposed) and sealed with a transparent film (Figure 5). A drainage tube is connected to the dressing through an opening of the transparent film which is connected to the vacuum pump (Baxter and Ballard, 2001). A stoma appliance (preferably with a tap to be able to attach a night drainage system) is then applied over the visible portion of fistulated bowel using a washer and paste to ensure an adequate seal is achieved as it is imperative for this to be air tight if this therapy is to be successful. If this method of management is chosen support from the tissue viability nurse is required.
Psychological support
Patients will require psychological support as they will often experience anxiety, feelings of loss, loss of self-esteem, depression and anger, particularly if they developed an ECF secondary to a postoperative complication. Patients may also develop body image issues related to stomas, fistulas and an open abdomen, which can inhibit recovery. It is therefore important to provide explanations at each stage as they can feel frustrated and struggle to understand the benefit of waiting to be medically optimised prior to surgery (Grainger et al, 2018).
Distal feeding
This is when the distal portion of the bowel is used as a site for feeding with nutritional support being administered either as chyme, elemental formula or fluid. Before initiating distal feeding the anatomy of the bowel and fistula should be established through radiology imaging to ensure that there are no distal enterotomies or obstructions and that the remaining bowel is long enough to absorb nutrients. Involvement of nurse specialists in nutrition and stoma care is required to teach the patient how to care for the tube, administer the feed and provide a suitable appliance (Figure 6). Distal feeding is increasingly being used ahead of surgical reconstruction to maintain the distal integrity, optimising bowel function following restoration of bowel continuity (Adaba et al, 2017).
Radiology
The gut should be reviewed radiologically before any further surgery is undertaken as the surgeon needs to be confident that there is no distal narrowing of the gut before attempting reconstructive surgery. For patients with Crohn's disease an MRI may be required to eliminate anal sepsis and if a patient has had previous complex surgery involving the urological system, the urinary tract needs assessing as it may require protecting by inserting ureteral stents. A CT angiography is required on patients who have severe cardiovascular disease and have suffered extensive mesenteric ischaemia to establish that there is sufficient blood supply to the gut. Ideally the radiological images should be reviewed by a radiologist experienced in GI radiology as these patients can have complex anatomy (Grainger et al, 2018).
Surgical management
Approximately 30% of patients with ECF will experience healing of the fistula following provision of nutrition, control of sepsis and minimising output usually within 4-8 weeks. If healing does not occur within this period, plans for definitive surgery should be initiated (Adaba et al, 2017). However, in a complex abdomen the process of forming a new peritoneal cavity takes around 6 months with the best indicator that the abdomen is ready for further surgery being the prolapsed portion of bowel (i.e. the portion of fistulated bowel that can be visualised within the wound bed of the ECF). If surgery is undertaken before this time, the patient is put at risk of further injury and complications (Grainger et al, 2018).
Reconstruction of the abdominal wall is an important element of the operation as failure to close the abdomen properly may lead to further complications such as re-fistulation, formation of incisional hernia or a poor cosmetic result. Mesh in the abdomen may be required to provide support to structures if there are multiple abdominal or large defects. However, a non-absorbable one should not be used as it is thought to be associated with increased infection rates (Grainger, 2018)
Conclusion
ECF is one of the most challenging postoperative complications to manage and requires a multidisciplinary approach if the outcome of closure is to be successful. Although patients are often keen to proceed with surgical closure at the earlier opportunity, they are better off waiting through at least 6 months of non-surgical management.