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Defining post-obstructive diuresis following posterior urethral valve ablation
Callum Lavoie1, Brian Chun1, Christine Do1
1Division of Urology, Children's Hospital Los Angeles, USC Institute of Urology, Keck School of Medicine of USC, Los Angeles, CA, United States.
Insights
Neonates with posterior urethral valves (PUV) experiencing high urine output after valve ablation are at increased risk for prolonged hospital stays. A 24-hour urine output threshold of 3.5 mL/kg/h may help identify patients at risk for post-obstructive diuresis.
Area of Science:
- Pediatric Urology
- Neonatal Critical Care
- Nephrology
Background:
- Posterior urethral valves (PUV) are a common cause of congenital lower urinary tract obstruction in neonates.
- Management of PUV can lead to post-obstructive diuresis (POD), potentially complicating patient recovery and hospital course.
- Identifying neonates at high risk for POD is crucial for optimizing care, yet data is limited.
Purpose of the Study:
- To define an initial urine output (UOP) threshold for identifying neonatal post-obstructive diuresis (POD) following posterior urethral valve (PUV) ablation.
- To investigate the correlation between post-ablation urine output and hospital length of stay (LOS).
Main Methods:
- Retrospective chart review of neonates undergoing cystoscopic valve ablation for PUV between 2004 and 2019.
- Analysis of urine output at 4- and 24-hours post-ablation, alongside serum creatinine, electrolytes, and fluid intake.
- Logistic regression models were used to assess predictors of prolonged hospital stay.
Main Results:
- Forty patients met inclusion criteria; mean age at ablation was 11.2 days.
- Post-operative mean urine output was 4.2 ± 3.7 mL/kg/h at 4 hours and 4.5 ± 2.2 mL/kg/h at 24 hours.
- A 24-hour UOP > 3.5 mL/kg/h was associated with over 5 times the odds of a prolonged hospital stay (>3 days) (OR: 5.50).
Conclusions:
- Neonates with PUV undergoing valve ablation are susceptible to POD.
- Elevated urine output post-ablation is a significant predictor of increased hospital length of stay.
- A 24-hour UOP threshold of >3.5 mL/kg/h can serve as an initial indicator for defining POD after PUV ablation.
Introduction:
Posterior urethral valves (PUV) are the most common cause of congenital lower urinary tract obstruction. Patients are at risk for post-obstructive diuresis (POD) following management of this obstruction which may prolong and/or complicate their subsequent hospital course. Despite this known physiologic effect, there is minimal data to define which patients are at highest risk for POD. Our objective was to define an initial urine output threshold for neonatal post-obstructive diuresis.
Methods:
A retrospective chart review was conducted on patients that were admitted to our Newborn and Infant Critical Care Unit (NICCU), in a tertiary care children's hospital, between 2004 and 2019 and underwent cystoscopic valve ablation for PUV. Outcomes of interest were length of hospital stay after posterior urethral valve ablation, serum creatinine and electrolyte values, fluid intake, and urine output at 4- and 24-h post-valve ablation. Chi-squared, Fisher's exact, and T-tests were conducted for descriptive statistical analyses as appropriate. Logistic regression analyses were conducted with adjusted models including patient demographic and clinical data.
Results:
Forty patients met inclusion criteria and the mean age at time of valve ablation was 11.2 days. Pre-operatively, maximum creatinine levels (ng/dl) achieved had a median value of 0.7 (IQR: 0.5-1.5). Post-operatively, the mean urine output (mL/kg/h) at 4-h was 4.2 ± 3.7, and at 24-h was 4.5 ± 2.2. Logistic regression analyses showed that those with a post-operative 24-h UOP > 3.5 ml/kg/h had more than 5 times the odds of a prolonged hospital length of stay (LOS) > 3 days (OR: 5.50; 95% CI: 1.23-24.51).
Discussion:
Neonates with PUV who undergo valve ablation are at risk of POD. Our findings suggest greater urine output after ablation to be a predictor of increased hospital length of stay. Utilizing a urine output (UOP) of >3.5 mL/kg/h may serve as a starting point for defining POD after posterior urethral valve ablation.
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