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Water balance, electrolytes and acid-base balance in extremely premature infants
N Takahashi1, J Hoshi, H Nishida
1Maternal and Perinatal Center, Tokyo Women's Medical College, Japan.
Insights
Extremely low birthweight (ELBW) infants managed in high humidity incubators experienced significant weight loss, primarily due to large urine output. Electrolyte and acid-base imbalances were common, particularly in appropriate for gestational age infants.
Area of Science:
- Neonatology
- Pediatric Nephrology
- Intensive Care Medicine
Background:
- Limited data exists on water balance and electrolyte disturbances in extremely low birthweight (ELBW) infants (< 1000 g) managed in high-humidity environments.
- Understanding these derangements is crucial for optimizing care in this vulnerable population.
Purpose of the Study:
- To retrospectively analyze water balance, electrolyte, and acid-base status in ELBW infants cared for in high-humidity incubators.
- To compare these parameters between infants appropriate for gestational age (AGA) and small for gestational age (SGA).
Main Methods:
- Retrospective analysis of 100 ELBW infants (72 AGA, 28 SGA) managed in closed incubators with high ambient humidity.
- Fluid intake was restricted and adjusted to maintain normal serum sodium levels.
- Water balance, electrolytes (Na, K), and acid-base status were monitored.
Main Results:
- Weight loss was significant (21.6% in AGA, 16.7% in SGA), primarily attributed to large urine volume, not insensible water loss.
- Hyponatremia (33.3%) and hypernatremia (8.0%) were observed.
- Hyperkalemia incidence was higher in AGA (37.0%) vs. SGA (14.8%) infants, though treatment was rare.
- Late metabolic acidosis was highly prevalent, especially in AGA infants (84.6% vs. 37.5% in SGA).
Conclusions:
- ELBW infants in high-humidity incubators exhibit significant water and electrolyte challenges, with distinct patterns in AGA and SGA infants.
- Management strategies for fluid and electrolyte balance require careful consideration of gestational age appropriateness.
- The high incidence of metabolic acidosis warrants further investigation and tailored interventions.
Abstract:
There are few reported studies of water balance and electrolyte abnormalities in extremely low birthweight (ELBW) infants weighing < 1000 g nursed in high humidity. We retrospectively analyzed water balance, electrolyte and acid-base balance in 100 ELBW infants, of whom 72 were appropriate for gestational age (AGA) and 28 were small for gestational age (SGA). They were cared for in closed incubators at almost full ambient humidity. Fluid intake was restricted to 50-60 mL/kg on the first day of life and was adjusted to maintain normal serum Na concentration. Weight loss in AGA and SGA infants was 21.6 and 16.7%, respectively, and was associated with large urine volume rather than insensible water loss. The incidence of hypernatremia (> 150 mEq/L) and hyponatremia (< 130 mEq/L) was 8.0 and 33.3%, respectively. The incidence of hyperkalemia in AGA infants was 37.0%, and 14.8% in the SGA group. However, hyperkalemia requiring treatment was rare. The incidence of late metabolic acidosis in AGA and SGA infants was 84.6 and 37.5%, respectively (P < 0.01). The difference in water balance and electrolyte abnormalities in AGA and SGA infants needs to be taken into account in managing ELBW infants.
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