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Hemodynamic disturbances and oliguria during continuous kidney replacement therapy in critically ill children
Sarah N Fernández Lafever1,2,3,4, Jorge López5,6,7,8, Rafael González5,6,7,8
1Pediatric Intensive Care Department, Gregorio Marañón General University Hospital, Madrid, Spain. sarahlafever@gmail.com.
Insights
Continuous kidney replacement therapy (CKRT) can cause hypotension and decreased urine output in pediatric intensive care unit (PICU) patients. While blood pressure stabilizes after 3 hours, oliguria persists and is linked to longer CKRT duration.
Area of Science:
- Pediatric Intensive Care
- Nephrology
- Critical Care Medicine
Background:
- Continuous kidney replacement therapy (CKRT) is required by approximately 1.5% of Pediatric Intensive Care Unit (PICU) admissions.
- Patients undergoing CKRT face significant mortality (30-60%) and a high incidence of CKRT-related hypotension (CKRT-RHI) (19-45%).
- Oliguria following CKRT initiation is common but has not been extensively studied.
Purpose of the Study:
- To investigate hemodynamic changes during the initial hours of CKRT in critically ill children.
- To explore the relationship between these hemodynamic shifts and subsequent urinary output.
Main Methods:
- A prospective observational study included 25 pediatric patients requiring CKRT in a single-center PICU.
- Data were collected over a 5-year period (January 2014 - December 2018).
- Hemodynamic parameters and urine output were monitored during the early phase of CKRT.
Main Results:
- CKRT-related hypotension (CKRT-RHI) occurred in 56.3% of patients, primarily in the initial hours.
- Blood pressure normalized within 3 hours, coinciding with decreased core temperature and heart rate.
- Urine output significantly decreased post-CKRT initiation, with 72% of patients becoming oliguric after 6 hours.
- Oliguric patients required significantly longer CKRT duration (28.7 days vs. 7.9 days).
Conclusions:
- CKRT initiation commonly leads to transient hemodynamic instability, which improves after 3 hours.
- Reduced urine output is a frequent complication, independent of fluid balance, hemodynamics, CKRT settings, or kidney function.
- Oliguria following CKRT initiation is associated with prolonged treatment duration in pediatric patients.
Background:
About 1.5% of patients admitted to the Pediatric Intensive Care Unit (PICU) will require continuous kidney replacement therapy (CKRT)/renal replacement therapy (CRRT). Mortality of these patients ranges from 30 to 60%. CKRT-related hypotension (CKRT-RHI) can occur in 19-45% of patients. Oliguria after onset of CKRT is also common, but to date has not been addressed directly in the scientific literature.
Methods:
A prospective observational study was conducted to define factors involved in the hemodynamic changes that take place during the first hours of CKRT, and their relationship with urinary output.
Results:
Twenty-five patients who were admitted to a single-center PICU requiring CKRT between January 1, 2014, and December 31, 2018, were included, of whom 56.3% developed CKRT-RHI. This drop in blood pressure was transient and rapidly restored to baseline, and significantly improved after the third hour of CKRT, as core temperature and heart rate decreased. Urine output significantly decreased after starting CKRT, and 72% of patients were oliguric after 6 h of therapy. Duration of CKRT was significantly longer in patients presenting with oliguria than in non-oliguric patients (28.7 vs. 7.9 days, p = 0.013).
Conclusions:
The initiation of CKRT caused hemodynamic instability immediately after initial connection in most patients, but had a beneficial effect on the patient's hemodynamic status after 3 h of therapy, presumably owing to decreases in body temperature and heart rate. Urine output significantly decreased in all patients and was not related to negative fluid balance, patient's hemodynamic status, CKRT settings, or kidney function parameters.
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