Overview

  • There is no such thing as ‘subacute obstruction’ – you are either obstructed or not!
  • Accounts for around 10% of all acute surgical admissions
  • 50-60% of the ‘obstructed patients we admit have adhesion related obstruction and will settle with appropriate conservative management.
  • There is no value in getting both a supine and erect AXR.  However, all patients should have both a CXR and plain supine AXR.
  • The majority of the problems experienced by patients with bowel obstruction are due to inadequate fluid management.  There are often massive fluid shifts in these patients and this must be corrected as a matter of priority.  Subsequent management then focuses on the aetiology of the obstruction.

Clinical Features

  • Abdominal pain - colicky, cramping
    • sharp & board rigid abdomen if bowel perforates
    • There is little relationship between the timing of pain & onset of vomiting (despite what is said in the texts).
  • Nausea & Vomiting
  • Diarrhea - early or post-obstruction after it has resolved)
  • Constipation - late
  • Fever and tachycardia - late, associated with strangulation or perforation
  • Previous surgery, radiotherapy
  • History of malignancy
  • Abdominal distention
  • Hyperactive 'tinkling' bowel sounds- early
  • Absent bowel sounds - late.

Investigations

  • CXR, supine AXR
  • CT is done in most cases these days especially on first presentation with confirmed AXR finding of SBO and really should be done on anyone you are planning to operate on.
    • Absolute Indicationsfor surgery:
      • Generalised peritonitis
      • Localised peritonitis
      • Visceral perforation
      • Irreducible hernia
    • Relative Indications
      • Palpable mass lesion
      • 'Virgin' abdomen
      • Failure to improve

Initial Management

  1. At least one decent size (green or brown) venflon in the ACF.
  2. Take blood for U&E, FBC, Amylase
  3. Order CXR (erect) and AXR (supine), consider CT scan
  4. Put in a urinary catheter and ask for hourly fluid balance
  5. Use crystalloid for resuscitation.  Do not write up bag after bag of normal saline as you can induce a hyperchloraemic metabolic acidosis.  3 litres of fluid over 24 hours will only cover maintenance fluids (30-40 mls kg-1 24hr-1), you need this plus any calculated losses .  It depends on the level of obstruction what losses the patient will have, eg high SBO lose proportionately more Na+ than lower down in the GI tract
  6. NG tube in all patients even if not vomiting
  7. clear fluids by mouth are allowed once NG is in place
  8. Morphine analgesia
  9. DVT prophylaxis - all patients
  10. You do not need to start antibiotics unless there is clinical evidence of sepsis or in at-risk patients

Continuing Management

  1. You need to identify those patients with strangulated obstruction - early surgical intervention is required
  2. Get the old notes
  3. Definite obstruction in a patient with no previous abdominal surgery needs a laparotomy
  4. Adhesion obstruction not settling after 4-5/7 needs a laparotomy
  5. There is no value in serial AXRs
  6. Patients not settling with no clear indication for a laparotomy may benefit from a CT abdomen
  7. Central lines are only required in patients with difficult fluid balance problems

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