Pocket ObGyn – Perioperative Oliguria & Ileus

Dec 8, 2019 admin PHỤ KHOA, SẢN KHOA 0

Pocket ObGyn – Perioperative Oliguria & Ileus
See Abbreviations

Definitions

  • Generally, urine output of <30 mL/h for 2–3 h or <500 mL/d
  • According to RIFLE criteria for AKI (Crit Care 2007:11R31) Risk: UOP <5 mL/kg/h for 6–12 h; or Cr ­ 1.5´ Injury: UOP <0.5 mL/kg/h for >12 h; or Cr ­ 2´

Failure: UOP <0.3 mL/kg/h for >24 h or anuria for 12 h; or Cr ­ 3´, or Cr >4 w/ acute rise >0.5 mg/dL

Loss: Persistent AKI w/ loss of kidney fxn >4 w

End stage: >3 mo of loss of kidney fxn

Common causes of perioperative oliguria
Prerenal

 

 

 

 

Renal

 

 

 

Postrenal

 –   True vol depletion – gastrointestinal dz (vomiting, diarrhea), renal losses (diuretics, osmotic diuresis, DI), skin or respiratory losses (insensible losses, sweat, burns), & 3rd space sequestration (edema, crush injury, skeletal fracture, preeclampsia)

–   HoTN (septic or cardiac shock); heart failure, cirrhosis, & nephrotic syn; selective renal ischemia

–   Tubular – acute tubular necrosis from prolonged intraop HoTN, nephrotoxic agents (NSAIDs, ACE inhibs, or angiotensin II blockers)

–   Glomerular – vasculitides

–   Interstitial – acute interstitial nephritis from nephrotoxic agents

–   Ureteral injury/blockade

–   Reflex spasm of the voluntary sphincter b/c of pain or anxiety; use of meds such as antichol & narcotics; detrusor atony as a result of Surg manipulation or anesthesia

–   Mechanical obst from an expanding hematoma or fluid collection or an occluded Foley catheter
Workup
  • History & physical exam
  • Check the Foley catheter & irrigate as a 1st
  • Check meds & hold/replace NSAIDs & other nephrotoxic Consider renally dosing other meds as needed.
  • Review operative report & anesthesia record: Intraop I/Os & BP
•   Labs

Urinalysis w/ review of sediment for muddy brown, granular casts (ATN) & eos (interstitial nephritis)

CBC, Cr, serum electrolytes & urinary electrolytes/Cr

Serum BUN/Cr: Ratio >20 generally sugg prerenal dz

FENa: <1% in prerenal dz & >2% in intrinsic renal dz. Consider FEurea if recent use of diuretics.

  • Renal US: Postrenal obst, chronic renal dz
Management
  • Prerenal: Fluid challenge of 500–1000 cc of Cr resolves in 1–3 d.
  • Renal: Identification & rx of underlying cause
•   Postrenal:

Acute retention: Transurethral or suprapubic catheter

Ureteric/bladder injuries: Consider percutaneous nephrostomy tube, trial of stenting (antegrade or retrograde) followed by delayed repair. Drain if urinoma.

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Perioperative Ileus

Definition
  • Obstipation w/ intolerance to oral intake due to postop intestinal
  • Physiologic ileus can last 1–3 d postop depending on Longer duration may be abnl.
Etiology
  • Inhibition of nml motility by postop inflammation, inhibition of spinal reflexes, opioids, vasoactive intestinal polypeptide, substance P, nitric oxide
Clinical Manifestations
  • Inability to tolerate PO diet, abdominal pain, distention, tympany on exam, decreased bowel sounds, delayed/decreased flatus
Diagnosis
  • Generally clinical, though should rule out small bowel obst (see below).
  • Intestinal dilatation w/o evid of transition point on CT, XR imaging of
Treatment
  • Bowel rest, NG tube if Vol resusc, repletion of electrolytes PRN.
  • Reduce/eliminate aggravating med (eg, opioids)
  • Serial abdominal exams until abdominal decomp/flatus.
Prevention
  • Epidural + local anesthesia instead of systemic or epidural opioids (Cochrane Database Syst Rev 2000;(4):CD001893)
  • Alvimopan (selective opioid receptor antag) FDA has limited access to med

as may inc risk MI in some pts.

  • Gum chewing immediately postop (World J Surg 2009;33(12):2557)
  • Scheduled postop laxative use after hysterectomy (Am J Obstet Gynecol 2007;196(4):311.e1)
  • Minimal manipulation of bowel intraop
  • Routine NG tube placement is NOT indicated (Cochrane Database Syst Rev 2007

18;(3):CD004929)

See Abbreviations

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