Vagus nerve stimulation induces concomitant respiratory alterations and a decrease in SaO₂ in children

Purpose: To analyze respiratory alterations and effects on SaO₂ caused by vagus nerve stimulation (VNS) in children with epilepsy. Methods: Polysomnographic recordings, including electroencephalography, thoracoabdominal distention, nasal airflow, SaO₂, and VNS artifact were evaluated in 10 children with pharmacoresistant epilepsy treated with VNS. Results: Each VNS caused a significant increase in respiratory frequency (p < 0.05) throughout the stimulation period and a decrease in thoracoabdominal-distention amplitude (p < 0.05), especially at the beginning of the stimulation. These respiratory alterations induced a decrease in SaO₂ from 1 to 5%. The effects of VNS on respiration differed significantly between rapid-eye-movement (REM) and non-REM (NREM) sleep states. Conclusions: VNS caused a pronounced change in respiration in children with epilepsy, and this induced a decrease in SaO ₂. It is possible that VNS has a neuroprotective effect, and this possibility calls for further investigation.