From the Research
Base deficit is a crucial parameter in assessing metabolic acidosis, and its absence in cord gas analysis can be concerning, but it is not necessarily ominous if other parameters like pH and bicarbonate levels are available to assess the severity of metabolic acidosis. When base deficit is not calculated, it's usually due to technical issues with the blood gas analyzer, insufficient sample volume, or severe sample hemolysis 1. The absence of base deficit calculation in the setting of metabolic acidosis is potentially problematic because it provides valuable information about the severity of the acidosis and helps distinguish between respiratory and metabolic components. Base deficit (or base excess when negative) quantifies the amount of acid needed to restore normal pH, making it an important parameter for assessing fetal acidemia and potential hypoxic-ischemic injury.
Key Points to Consider
- The calculation of base deficit can vary depending on the blood gas analyzer used, with different algorithms and equations employed by different brands 2.
- The prevalence of metabolic acidosis can be affected by the choice of algorithm and the compartment in which base deficit is calculated (blood or extracellular fluid) 2.
- A recent study highlights the importance of standardized evaluation of cord gases in neonates at risk for hypoxic ischemic encephalopathy, emphasizing the need for timely identification and evaluation of neonates with umbilical-cord acidemia 3.
- If base deficit is missing from cord gas results, clinicians should consider requesting a recalculation if the original sample is available, or rely on other parameters like pH and bicarbonate levels to assess the severity of metabolic acidosis while recognizing this provides less complete information for neonatal risk assessment 1.
Recommendations for Clinical Practice
- Clinicians should be aware of the potential variations in base deficit calculation and the importance of using a standardized approach to evaluate cord gases in neonates at risk for hypoxic ischemic encephalopathy.
- The use of other parameters like pH and bicarbonate levels can provide valuable information for assessing the severity of metabolic acidosis, even in the absence of base deficit calculation.
- Further research is needed to establish clear guidelines for the calculation and interpretation of base deficit in cord blood gas analysis, as well as to determine the optimal approach for managing neonates with metabolic acidosis 4.