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416 Electrolytes and acid-base disturbances: The impact and relationships with tubular dysfunction among critically ill children
  1. Wun Fung Hui,
  2. Kam Lun Hon
  1. Hong Kong


Background Electrolytes and acid-base disturbances are common yet largely ignored problems in critical care. Although closely related, the relationship between electrolytes disturbance and acute kidney injury (AKI) has not been extensively studied among critically children.

Objectives We presented the results of the interim analysis of an ongoing prospective cohort study on the epidemiology of acute kidney injury and electrolytes disturbances (E-AKI-Drug Study) in a newly established paediatric intensive care unit (PICU).

Methods All children aged 1 month to 18 years old admitted to the PICU of our hospital after June 2020 would be enrolled. Those with pre-existing chronic kidney disease, impaired renal function for ≥3 months, immediate post-renal transplant and short stay in PICU <1 day with no blood taking would be excluded. Appropriate urinary investigations would be carried out if there were electrolytes disturbances. For children with more than two types of electrolytes disturbances, urine beta-2-microglobulin and amino acid profile would also be determined. AKI was defined using the KDIGO criteria. The results of the initial 4 months of data collected would be presented.

Results Altogether 63 episodes of admission were included for the interim analysis. 58.7% of the subjects were male and the median (25th, 75th percentile) age was 6.1 (1.6, 12.7) years old. 49.2% of patients had a diagnosis of malignancy and 9.5% received bone marrow transplantation. The overall incidence of AKI during PICU stay was 55.6%. The median number of types of electrolyte disturbance was 4 (2, 5) types. Hypophosphataemia (85.5%), hypocalacemia (77.4%) and hypokalaemia (61.3%) were the three most common types of electrolytes disturbances respectively. The incidence of metabolic acidosis and alkalosis were 90.3% and 35.5% respectively. Urinary wasting of potassium, phosphate and magnesium were common among children with hypokalaemia, hypophosphataemia and hypomagnesaemia, occurring in 25%, 50% and 87.5% of the respective children (figure 1). Among children with more than two types of electrolytes disturbances, abnormal urinary beta-2-microglobulin level occurred in 64.7% of patient (median level 0.9 [0.2, 5.2] μg/ml). The median degree of aminoaciduria was 23.1 (9.5, 47.6)%. Children requiring inotropic (5.0 vs 3.0 types p<0.01) and ventilatory support (5.5 vs 4.0 types, p=0.008) and children with AKI (5.0 vs 3.0 types, p<0.01) had higher number of electrolytes disturbances. Besides, children with AKI had more hypernatraemia (35.3% vs 10.7%, p=0.036) and hypokalaemia (73.5% vs 46.4%, p=0.029). Those with stage 3 AKI also had highest proportion of hyperphosphataemia compared to those with less severe or no AKI (p=0.002). The number of types of electrolytes disturbances was associated with longer duration of ventilation (r=0.613, p=0.011) and PICU length of stay (r=0.567, p<0.001), as well as increased risk of PICU mortality (relative risk 4.3 [95% confidence interval 1.4, 12.7]).

Conclusions Electrolytes and acid-base disturbances were commonly encountered among critically ill children. Urinary wasting of the electrolytes and proximal tubular dysfunction were commonly observed among children with multiple electrolytes disturbances. The degree of electrolytes disturbances would contribute to longer ventilator days, PICU stay and even mortality, indicating a need to address the tubular health and its impact in critically ill children.

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