Oculocardiac Reflex Brain Wave Monitor

Bradycardia, Strabismus

Oculocardiac reflex during routine strabismus surgery was prospectively observed in association with routine brain wave monitoring. Providence Hospital institutional review board (IRB) approved this observational study without need for consent.

Introduction: The oculocardiac reflex (OCR), bradycardia that occurs during strabismus surgery, is blocked by anticholinergics and enhanced by opioids and dexmedetomidine. Two recent studies suggest that deeper inhalational anesthesia monitored by bispectral index (BIS) protects against OCR; the investigators wondered if our data correlated similarly. Methods: In an ongoing, prospective study of OCR elicited by 10-second, 200 gram square-wave traction on extraocular muscles (EOM) from 2009 to 2013, anesthetic depth was estimated in cohorts using either BIS or Narcotrend monitors. The depth of anesthesia was deliberately varied between first and second EOM tested.