Eighty infants with proliferative retinopathy of prematurity (ROP) were treated with peripheral retinal cryoablation. Among the serious systemic complications encountered were three instances of respiratory arrest and one of cardiorespiratory arrest. Recommendations that may help prevent these adverse systemic effects in premature infants include: (1) avoidance of excess subconjunctival anesthetic doses, (2) preoperative administration of systemic atropine to minimize the oculocardiac reflex, (3) consideration of an analgesic agent to decrease the pain and exhaustion, and (4) cardiorespiratory monitoring in a hospital setting, with an intravenous line in place, at the time of treatment.