243 - Early onset hyponatremia: Epidemiology and management in extremely preterm infants.
Saturday, April 29, 2023
3:30 PM – 6:00 PM ET
Poster Number: 243 Publication Number: 243.243
Namrata Todurkar, University of British Columbia Faculty of Medicine, Vancouver, BC, Canada; Susan G. Albersheim, University of British Columbia Faculty of Medicine, Vancouver, BC, Canada; Cherry Mammen, BC Children's Hospital, Vancouver, BC, Canada; Li Wang, University of British Columbia Faculty of Medicine, Vancouver, BC, Canada; Jeffrey N. Bone, British Columbia Children's Hospital Research Institute, Vancouver, BC, Canada; Rajavel Elango, University of British Columbia Faculty of Medicine, Vancouver, BC, Canada
Clinical Fellow University of British Columbia Faculty of Medicine Vancouver, British Columbia, Canada
Background: Early onset hyponatremia (EOH) is commonly reported in extremely preterm infants (EPI) admitted to Neonatal Intensive Care Units. Numerous factors influence serum sodium (Na) concentrations in a preterm, including Na and fluid intake. Epidemiological studies in this population are lacking, and there are no clear guidelines for how to investigate or treat hyponatremia in EPI. Objective: 1. To explore investigations and interventions chosen for EOH in EPI. 2. To determine association of EOH with sodium and total fluid intake (TFI) in EPI. Design/Methods: This was a single center retrospective cohort study of 100 EPI (< 28 wk gestation). Data from day 1 to 14 after birth was collected, including: Na values, TFI (ml/kg/day), total Na intake (mmol/kg/day) and daily weight; investigations and treatment interventions following hyponatremia days (HD=one or multiple hyponatremia episodes in a day). Mild, moderate and severe hyponatremia were defined as Na 130-134, Na 126-129 and Na < 125 mmol/L, respectively. Mixed-effects logistic regression was used to investigate relationship between TFI and Na intake and probability of hyponatremia, with multivariate analysis for statistically significant (p< 0.05) results. Results: Prevalence of EOH in EPI was 79%. Of the 393 HDs in the first 2 wk, the highest frequency was seen on day 8 (Figure 1). Mild progressed to moderate hyponatremia in 45% of infants; moderate progressed to severe hyponatremia in 48.6%. Repeat Na was ordered for 82.1% of HD. Rarely were urine investigations (5.3%) ordered. Over half of HD were treated by increasing Na intake (55.7%), 6.8% by restricting TFI (Table 1). Odds of hyponatremia increased by 43% for each 1mmol of Na/kg/day (OR=1.43,95%CI =1.32 to 1.56, p< 0.001 Figure 2), and by 8% for every 10ml of fluid/kg/day (OR=1.08,95%CI=1.00 to 1.16, p=0.049). Hyponatremia correlated with fluid overload evident by daily cumulative weight change (Figure 1). Including both TFI and Na intake in the same regression model, increasing Na intake by 1 unit was associated with 17% increased odds of EOH.
Conclusion(s): EOH is very common in EPI, but under-investigated. Recognition of mild hyponatremia is key as nearly half progress to moderate and severe hyponatremia. The most common response to hyponatremia was to repeat Na without investigating etiology (acute kidney injury, sodium loss, Syndrome of Inappropriate Antidiuretic Hormone Secretion, etc.), and supplement Na which likely resulted in fluid overload. Prospective studies looking at EOH with planned investigations may help better understand the cause of this key electrolyte abnormality in EPI.
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