This document discusses post-operative complications related to the genitourinary system. It outlines risk factors for post-operative nausea and vomiting (PONV) and strategies for prevention. It also discusses acute kidney injury, urinary retention, and urinary tract infections as common genitourinary complications. For each complication, it describes the causes, risk factors, signs, and treatment approaches. Prevention of complications through proper fluid management, avoidance of nephrotoxic drugs, and aseptic catheterization is emphasized.

1. Post operative nausea and vomiting(PONV)
• consequences of PONV in PACU include delayed discharge from the
PACU, unanticipated hospital admission, increased incidence of
pulmonary aspiration, and significant postoperative discomfort and
patient dissatisfaction
• Risk factors for PONV can be grouped into three categories: patient,
anaesthetic, and surgery-related factors
1. Patient factors: female patients, history of motion sickness, previous
history of PONV, non-smokers, young patients
2. Anaesthetic factors: use of post-op opioids, nitrous oxide, volatile
inhalational anaesthetics e.g. ether, other IV anaesthetics e.g.
ketamine and neostigmine
3. Surgical factors: gynaecology, ENT, strabismus surgery, laparotomy,
craniotomy, breast surgery

2. Physiology of vomiting centre and CTZ

3. Pharmacological treatment

4. Prevention
• Avoidance of general anaesthesia by the use of regional anaesthesia
• Preferential use of propofol
• Avoid use of nitrous oxide and volatile anaesthetics
• Minimize postoperative opioids
• Adequate hydration

5. Genitourinary complications
• Urinary retention
• Acute kidney injury
• Urinary tract infection

6. Acute kidney injury
• This complication results in oliguria
• The causes are divide into prerenal, renal and post-renal
• Prerenal causes: hypovolemia (bleeding, sepsis, third-space fluid loss,
inadequate volume resuscitation), hepatorenal syndrome, low cardiac
output, renal vascular obstruction, intra-abdominal hypertension
• Renal causes: ischemia (acute tubular necrosis), radiographic contrast
dyes, rhabdomyolysis, tumour lysis, haemolysis
• Post-renal causes: blocked catheter or malpositioned, bladder output
obstruction

7. Treatment
• Fluid hydration IVF in hypovolemic patients based on the degree of
fluid depletion
• Stop or avoid drugs with nephrotoxic potential e.g. ACE Inhibitors
• Monitoring volume input and output
• Renal replacement therapy [in oliguria despite volume repletion or
electrolytes imbalances

8. Urinary retention
• Inability to void despite a bladder volume of 500-600ml
• Incidence in PACU is 5-70%
• Risk factors: age older than 50 years, male gender, volume of
intraoperative intravascular fluid infusion, duration of surgery, and
bladder volume on admission
• Type of surgery is also predictive most common in anorectal and joint
replacement surgery
• Commonly used perioperative medications such as anticholinergics,
β-blockers, and narcotics also contribute to urinary retention
• General anaesthetics act as smooth muscle relaxants and lead to
decreased bladder contractility while interfering with autonomic
regulation of the detrusor

9. • Spinal and epidural anesthetics impact voiding by effectively
interfering with the afferent and efferent nerves and micturition reflex
arcs as they enter and exit the spinal cord and make their way up to the
central micturition centers
• Opioids cause retention by increasing sphincter tone by
overstimulation of the sympathetic nervous system leading to an
increase in outlet obstruction

10. Treatment
• Catheterization until bladder control is regained
• Medication - Alpha-blocker; Mirabegron to relax the urethra

11. Urinary tract infections
• This occurs during catheterization mostly especially with long
indwelling catheters that increase risk
Management
1. Prevention- prophylactic antibiotics reduces by 50%
2. Aseptic techniques when inserting catheter
3. Treatment-antibiotics eg Ceftriaxone