Stoma Principles Flashcards

1
Q

What is a stoma?

A

Artificial opening of a luminal organ into the external environment – may be temporary or permanent, it may be end-on or a loop.

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2
Q

What are the indications for a stoma?

A
  1. For input: feeding (Percutaneous endoscopic gastrostomy)
  2. For output: decompression/ lavage, defunctioning/ diversion, draining/ exteriorization (urine, faeces)
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3
Q

How can we classify types of stomas?

A
  1. Small Intestine, Large Intestine, Small-Large Intestine
    - Small and Large intestine individually can be end or loop stoma
    - Small-large – ileo-colic stoma: 2 lumens present - one leading to ileum, one to colon
  • end: transected nd of the intestine is exteriorize and fashioned as a stoma (only 1 lumen)
  • Loop Stoma – loop of intestine is exteriorized and a stoma is fashioned (2 lumen)
  • Double Barrel Stoma – intestine is severed and brought out as 2 ends to fashion a stoma (i.e. ileo-colic stoma) (2 lumen)
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4
Q

When would you recommend a temporary or permanent stoma?

A

Temporary
- Decompression – relief of bowel obstruction causing proximal dilatation, i.e. end colostomy or transverse loop colostomy for obstructed colon tumour (proximal large bowel is decompressed)
- Defunctioning / Diverting – i.e. loop ileostomy after low AR (small bowel contents diverted from large colon)

Permanent
- Absolute – i.e. end colostomy after APR or end ileostomy after panproctocolectomy (where there is no distal bowel remaining)
- Relative – reversal of stoma is dependent on patient factor, disease factor and surgical factors (many created intestinal stoma are not eventually reversed)

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4
Q

What are the principles in deciding the placement of the stoma? (6)

A
  • Over the rectus sheath which reduces risk of prolapse,
  • Away from the surgical incision which reduces risk of wound contamination and infection
  • Away from skin creases or bony prominences - stoma wafer can be flushed with the skin (gaps between skin and wafer - leakage
    of fluid - skin excoriation & infection)
  • Away from old surgical scars - reduces risk of hernia
  • Sited for easy accessibility i.e. not under a large fold of abdominal fat
  • Intra-operatively, avoid tension over the stoma to marked site - causes decreased vascularity of the stoma - risk of stoma necrosis
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4
Q

How do you decide what type of stoma to do?

A
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5
Q

What should be done on physical examination of a stoma?

A
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6
Q

How is a loop colostomy created?

A

A loop of colon is brought to the surface of the body and may be supported on a rod, which is removed after 5-7 days. The bowel wall is partially cut to produce two openings—of an afferent limb and an efferent limb. The opening of the afferent limb leads to the functioning part of the colon, through which stool and gas pass out. The opening of the efferent limb leads into the non- functioning part of the colon.

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7
Q

What are the indications for a loop colostomy?

A
  1. defunction an inflamed sigmoid in diverticular disease
  2. defunction a distal anastomosis.
  3. prophylactic decompression before RT in an obstructing rectal tumour.
  4. diversion of fecal flow in fourner’s gangrene, sacral sore, RVF, rectal perforation, perianal crohn’s or anal incontinence
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8
Q

When would you think a loop ileostomy has been performed?

A

2 adjacent lumens and bag contains greenish liquid contents.

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9
Q

What are the indications for a loop ileostomy?

A
  1. defunctioning/decompression of an obstructed colon (in cancer)
  2. defunctioning of a distal anastomosis (after resection and primary anastomosis either as an emergency or after radiotherapy), or 3. diversion of fecal flow in fourner’s gangrene, sacral sore, RVF, rectal perforation, perianal crohn’s or anal incontinence
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10
Q

What is a double barrel stoma? When is it done?

A

an end ileostomy (small bowel) and a mucous fistula (the remaining colon) sited beside each other.

Done when the cecum is removed.

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11
Q

What is the thought process when seeing an end ileostomy?

A

2 possibilities: temporary end ileostomy or permanent end ileostomy (to differentiate do a DRE to check for anal canal patency)

No anal canal → permanent end ileostomy, the patient has undergone panproctocolectomy.
This occurs most commonly in severe ulcerative colitis but also in familial polyposis and some cases of colorectal cancer (i.e. HNPCC). After a panproctocolectomy the ileostomy is permanent.

Anal Canal Present → Temporary end ileostomy. Patient has undergone an emergency subtotal colectomy, which leaves part of the sigmoid colon and rectum left in place; for acute ulcerative colitis; acute ischaemic bowel; or neoplastic obstruction of the sigmoid.

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12
Q

When seeing an end colostomy, what is the thought process?

A

Anal Canal Absent → permanent end colostomy, patient most probably has undergone an APR for low rectal tumour

Anal Canal Present → possible temporary end colostomy, patient has undergone a Hartmann’s resection for an obstructing rectal tumour

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13
Q

When anterior resection with hartman’s procedure is performed, what are the stoma outcomes possible?

A

In the first, the distal, non-functioning part of the colon and the rectum can be stapled or sewn closed and left inside the abdomen as a rectal stump. The proximal colon is then taken out as an end colostomy. Because the rectum has not been removed, the urge to have a bowel movement may occur. Mucus and some old stool, if present, will be passed.

Less commonly, two separate stomas may be created. One stoma is the exit of the functioning part of the colon through which stool and gas pass. The second stoma opens into the non- functioning portion of the colon and rectum and is called a mucous fistula. The second stoma is usually small, flat, pink-red in colour, and moist, and it produces only mucus.

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14
Q

After APR is done and end colostomy performed, where is the site of it?

A

through the lateral edge of the rectus sheath, 6cm above and medial to the ASIS. (i.e. midway between ASIS and umbilicus)

15
Q

What is a urostomy? What are the indications? How is it done? Concerns?

A

This is a general term for the surgical diversion of the urinary tract. The main reasons for a urostomy are cancer of the bladder, neuropathic bladder, and resistant urinary incontinence.

The bladder is usually removed, but this may depend on the underlying condition. Formation of an ileal conduit is the most common procedure, which constitutes isolation of a segment of ileum. One end of the ileum is closed and the two ureters are anastomosed to it. Finally, the open end of the ileum is brought out onto the skin as an everted spout and will look similar to an end ileostomy. Urine drains almost constantly from the kidneys through the ureters and ileal conduit into a bag.

Patient may present with hyperchloremic metabolic acidosis and/or less frequently hypokalemia, hypocalcemia and hypomagnesemia*

15
Q

What are the principles in fashioning a stoma? (7)

A
  • Adequate bowel mobilization to ensure proper protruding well vascularized tension free approximation to abdominal wall
  • Appropriately sized stoma fascia opening and skin aperture → too large will risk parastomal hernia, too small will risk ischemia, venous congestion, necrosis, stricture, obstruction
  • Ensure correct bowel orientation and mesentery not twisted
  • Create peritoneal window over colonic mesentery below stoma and use of stoma rod may decrease risk of stoma retraction
  • Closure of all abdominal incisions before maturing stoma to avoid wound contamination
  • Ileostomy should be sprouted 2-3cm above abdominal wall to allow output into appliance and not onto skin
  • Adequately spaced and snug sutures to abdominal wall dermis to reduce risk of mucocutaneous dehiscence
16
Q

What types of stoma bag systems are there?

A

Single piece systems stick on to a patients skin

Two-piece systems have a separate base (a flange) that sticks to the skin, and the bag attaches to this. Bag can be changed without removing the flange.

17
Q

Complications of Stoma?

A

Early
- Bleeding
- Stoma Necrosis (stoma appears dusky (grey to black); check by intubating with a glass tube into the stoma to look at colour of mucosa) → refashion stoma
- Obstruction (faecal impaction → explore with finger, enema / secondary to adhesion – more in ileostomy)
- Leakage → skin erosion, parastomal infection → re-site
- Stoma diarrhoea (high output) → r/o intra-abdominal sepsis, correct water & electrolyte imbalance (hypoNa+, hypoMg2+, hypoK+), add antimotility agent to thicken output (loperamide ± codeine) – see below
- Peristomal ulceration – if non-healing, ?pyoderma gangrenosum → evaluate for IBD (treat: steroids)

Intermediate
- Prolapse of bowel → refashion/refresh
- Retraction → refashion

Late
- Parastomal hernia (+ve cough impulse) → conservative, 10-30% will require surgery
- Stenosis (unable to pass finger through) → refashion
- Fistulae
- Skin excoriation
- Psychological problem

18
Q

What is a high stoma output?

A

Defined as one producing an effluent volume >1000/ml/day

19
Q

What is the risk of a high stoma output?

A

Clinically significant when effluent volume > 2000ml/day → cause electrolytes derangements

20
Q

What are the causes of high output stoma?

A
  • Primary cause: loss of normal daily secretions (1.5L saliva, 2-3L gastric juice, 1.5L pancreatico-biliary)
  • Other causes of high output (exclude first): intra-abdominal sepsis, infective enteritis (i.e. clostridium difficile), partial / intermittent bowel obstruction, recurrent disease in the remaining bowel (i.e. Crohn’s disease or irradiation bowel disease), sudden stopping
    of drugs (i.e. steroids or opiates), administration of prokinetic drugs (i.e. metoclopramide)
21
Q

What is the pathophysiology of hypokalemia in high output stoma?

A
  • Sodium depletion (each L of jejunostomy fluid contains 100mmol/l of Na+) leading to secondary hyperaldosteronism (increase
    Na+ reabsorption and concomitantly greater than normal urinary loss of K+ and Mg2+)
  • Hypomagnesaemia leading to increase renal potassium excretion
22
Q

What is the management of high output stoma?

A
23
Q

Why is a colostomy preferred over ileostomy for decompression and diversion of fecal flow?

A

less irritative material,

lower volume so less likely have fluid and electrolyte abnormalities,

less often bag change,

b12 can be absorbed as absorbed in terminal ileum, easier for bile acids to be reabsorbed also