Falls in oxygen saturations accompany electrographic seizures in term neonates: an observational study

Background

Effective seizure detection is important however, clinical signs of seizure activity may be subtle in neonates. This study aimed to systematically investigate SpO₂ and respiratory pattern changes associated with EEG seizures in term-born neonates.

Method

An observational study in term neonates at risk of seizures admitted to a single tertiary level neonatal intensive care unit. Synchronised high-resolution physiological data (ECG, pulse oximetry, respiration) and EEG/amplitude-integrated EEG (aEEG) monitoring were recorded. Sections of traces with evidence of clear EEG seizure activity were compared with physiological data recorded at the same time.

Results

22/44 (50%) neonates who had aEEG monitoring were noted to have electrographic seizures. Physiologic download measurements were available for 11 of these neonates. In nine of these, an acute drop in oxygen saturation (SpO₂) of at least 5% was noted in at least one seizure. Accompanying apnoeas were noted in three neonates.

Conclusion

Acute decreases in SpO₂ were seen in term neonates associated with seizures and these were not always accompanied by an apnoeic episode. Physiologic download in association with EEG monitoring may assist in improving seizure detection. Unexplained drops in SpO₂ could indicate further investigation for possible seizures in at-risk neonates.

Impact

A decrease in blood oxygen saturation (SpO₂) associated with EEG seizures can occur in term infants with HIE or perinatal stroke.

Drops in SpO₂ associated with EEG seizures in term infants with HIE or stroke may occur in the absence of apnoeas.

Unexplained acute falls in SpO₂ in sick neonates may suggest possible seizures.

Drops in SpO₂ associated with seizures in term infants can occur over less than 3 minutes.

Physiological monitoring alongside EEG monitoring could help to improve seizure detection.