What causes changes in urine output in post-cesarean section (c/s) patients?

Causes of Urine Output Changes in Post-Cesarean Section Patients

Urine output changes in post-cesarean section patients should be assessed on a case-by-case basis, as they can indicate various complications that affect patient morbidity and mortality. 1

Common Causes of Urine Output Changes

Hydration Status Related

• Postoperative hydration status significantly affects urine output and should be routinely assessed in post-cesarean patients 1
• Intraoperative blood loss correlates with fluid volume shifts that can decrease urine output in the immediate postoperative period (4 hours post-surgery) 2
• Significant blood loss during cesarean section can lead to hemodynamic instability, which directly impacts renal perfusion and subsequent urine output 2

Urinary Retention

• Postpartum urinary retention occurs in approximately 3.38% of women after cesarean section 3
• "Lack of progress of labor" is a significant risk factor for developing urinary retention after cesarean delivery 3
• Epidural analgesia with morphine significantly increases the risk of post-cesarean urinary retention (33.3%) compared to other analgesic methods such as patient-controlled epidural analgesia (15%) or intramuscular pethidine (16.7%) 4

Catheter-Related Issues

• Indwelling urinary catheters commonly used during cesarean sections can lead to urinary tract infections, which may subsequently affect urine output patterns 5
• Immediate removal of urinary catheters after cesarean delivery (versus delayed removal) can reduce the risk of urinary tract infections but may temporarily affect voiding patterns 5

Anatomical Considerations

• Bladder distortion after repeat cesarean sections can cause dysuria and altered voiding patterns 6
• Pelvic organ changes following cesarean section can contribute to urinary dysfunction, with urinary incontinence occurring in 12.7% of women post-cesarean 1

Assessment and Management Approach

Evaluation Protocol

• Assessment of urine output should be performed selectively based on patient risk factors and specific procedural considerations 1
• Bladder volume measurement using ultrasound (Bladderscan) shows strong correlation with catheterized volumes (r = 0.807) and can be used to assess retention non-invasively 7
• Post-void residual volumes greater than 150 ml indicate urinary retention requiring further management 3

Management Considerations

• Patients with decreased urine output should be assessed for hemodynamic stability, as there is a significant relationship between free fluid volume and hemodynamic instability 2
• For patients with urinary retention, 12% may require catheterization at 1 day postpartum, though most achieve spontaneous micturition before hospital discharge 4
• Choice of postoperative analgesia should consider the impact on urinary function, as epidural morphine significantly increases catheterization rates (21.7%) compared to other methods (3.3-6.7%) 4

Long-Term Implications

• At 3-month follow-up, approximately 4% of women may have obstructive voiding problems and 4.7% may have irritative voiding symptoms after cesarean section 4
• By 1-year post-cesarean, most urinary symptoms resolve with only rare cases of persistent incomplete emptying or incontinence 4