Association between base excess levels and clinical outcomes among very low birth weight infants: a multicenter birth cohort study in South Korea.

BACKGROUND

The impact of metabolic acidosis on short-term outcomes and mortality in very low birth weight infants (VLBWIs) has not been well studied.

PURPOSE: To investigate the potential association between metabolic acidosis and the clinical outcomes of VLBWIs in South Korea.

METHODS

Between 2013 and 2019, data were collected from the Korean Neonatal Network, which covers a multicenter birth cohort spanning 75 hospitals. Our study cohort included 14,519 infants with a birth weight of less than 1,500 g who were admitted to the neonatal intensive care unit. Blood gas measurements taken within 1 hour of birth were used to evaluate the clinical outcomes, which were categorized into 5 groups according to base excess (BE) levels. We assessed respiratory outcomes, neurological morbidities, and infection-related and gastrointestinal outcomes along with mortality rates.

RESULTS

We analyzed 10,394 VLBWIs based on the inclusion criteria. A BE level below -9 suggested a significantly high risk of various respiratory outcomes, including air leak syndrome (adjusted odds ratio [aOR], 2.071; 95% confidence interval [CI], 1.305-3.285), massive pulmonary hemorrhage (aOR, 2.317; 95% CI, 1.502-3.575), pulmonary hypertension (aOR, 2.296; 95% CI, 1.667-3.161), and neonatal respiratory distress syndrome (aOR, 2.219; 95% CI, 1.778-2.769). These infants also exhibited an elevated risk of neurological (aOR, 2.797; 95% CI, 2.314-3.380), infection-related (aOR, 2.082; 95% CI, 1.653-2.623), gastrointestinal (aOR, 1.979; 95% CI, 1.408-2.783), and mortality (aOR, 2.683; 95% CI, 2.076-3.466) outcomes.

CONCLUSION

Our findings highlight the potential effect of metabolic acidosis at birth on the clinical outcomes of VLBWIs. A strong correlation was observed between metabolic acidosis and neurological morbidity. These findings offer important insights for managing VLBWIs with metabolic acidosis and suggest the need for future research on acid-base balance risk factors.