Urinary Post-Op Complications Flashcards
what is acute kidney injury (AKI)?
an abrupt decrease in kidney function
what is the criteria in identifying AKI?
- ≥50% rise in serum creatinine from baseline
- increase in serum creatinine
- urine output <0.5mls/kg/hour
what are the stages of AKI?
measured by raise in creatinine level relative to baseline:
stage 1: 1.5-2x the baseline
stage 2: 2-3x the baseline
stage 3: >3x the baseline
what are the three different kinds of causes of AKI?
- pre renal - reduction in blood flow and GFR
- intra renal - damage to kidney structures
- post renal - obstruction in urinary output
what are the pre renal causes of AKI?
- sepsis
- dehydration
- haemorrhage
- renal artery stenosis
- cardiac or liver failure
what are the intra renal causes of AKI?
- nephrotoxins such as NSAIDs, ACE-i, chemotherapy drugs
- parenchymal disease such as glomerulonephritis, rhabdomyolysis
what are the post renal causes of AKI?
- renal stones
- tumour
- urinary retention
- catheter blockage
- prostatic enlargement
what investigations should be done for a patient with AKI?
assess their fluid status scan bladder for signs of retention review drugs for signs of nephrotoxins urine dip can help identify underlying cause bloods and blood gas
what imaging should be done for a patient with AKI?
USS of the kidneys, ureters and bladder to check for obstructive causes as indicated by hydronephrosis
how would you manage an AKI patient’s fluid status?
look for signs of dehydration and give resuscitation fluids
what is the standard fluid resus. regime?
500mls 0.9% saline IV over 15 minutes
what would you continually monitor in an AKI patient?
monitor urine output using a catheter
regular blood tests to assess U&Es to monitor creatinine
true or false: a patient that does not improve with fluid resus. in AKI most likely has a intra or post renal cause
true.
what drugs would you stop in a patient with AKI?
- ACE-i or ARBs
- NSAIDs
- Aminoglycoside antibiotic e.g. gentamycin
- potassium sparing diuretics
what drugs would you alter in a patient with AKI?
- metformin (risk of lactic acidosis)
- diuretics (in case of intra vascular fluid depletion)
- low molecular weight heparin
what is acute urinary retention?
the inability to completely empty the bladder
what are the clinical features of acute urinary retention??
- little or no urine passed in the post-operative period
- feeling the need to void
- suprapubic mass that has a dull percussion note
what are the common underlying causes for post-operative urinary retention?
- uncontrolled pain
- constipation
- infection
- anaesthetic agents (e.g. spinal or epidural)
what are the risk factors for urinary retention?
- age >50
- male
- previous retention
- pelvic or urological surgery
- spinal or epidural anaesthesia
- medication e.g. antimuscarinics, alpha agonists, opiates
what investigations should be conducted in a patient with suspected urinary retention?
an ultrasonic bladder scan to assess post-void residual volume
how would you manage a patient with post-operative urinary retention?
tends to respond spontaneously, but if not then catheterise the patient
TWOC them and check if they re-enter retention
what if the patient re-enters urinary retention post-TWOC?
they need to be re-catheterised and TWOC should be attempted again in 1-2 weeks
what is the most common organism for causing a UTI?
e. coli
what are the risk factors for a post-operative UTI?
- age
- female
- comorbidities (DM, renal failure)
- catheterisation
- retention
- renal stones
what are the clinical features of a UTI?
urinary frequency, urinary urgency, dysuria
patients can also present with delirium, septic, or in urinary retention
what are the clinical signs of a UTI?
patient will be pyrexial and have suprapubic pain
what investigations should be taken in a patient with a suspected UTI?
- urine dip which is later sent for microscopy if nitrates/leukocytes/blood are positive
- routine bloods
- bladder scan to check if the patient has entered retention
- renal USS if pyelonephritis is suspected
how would you manage a patient with a post-op UTI?
- maintain patient hydration
- treat with antibiotics
- change catheter before starting antibiotics
what is the recommended antibiotic for UTI treatment?
nitrafurantoin
