Oculocardiac reflex--peribulbar block or opioid-relaxant anaesthesia

Surgical and anesthetic influences of the oculocardiac reflex in adults and children during strabismus surgery

One of the most common untoward occurrences during strabismus surgery at all ages is the oculocardiac reflex. Although typically easily treated, the sudden bradycardia or cardiac arrest may add a few gray hairs to ophthalmologists and anesthesiologists alike as it can be potentially fatal. This updated review of the literature and novel detailed treatment algorithm may prevent patient morbidity and mortality through proper recognition of at-risk patients and rapid treatment through proper communication between surgical and anesthesia physicians/providers.

The Oculocardiac Reflex: A Review

BACKGROUND

A typical oculocardiac reflex (OCR) is a moderate trigemino-vagal bradycardia elicited by tension on an extraocular muscle (EOM) during strabismus surgery; however, many other orbital stimuli can elicit cardiac slowing including retinopathy of prematurity examination.

METHODS

World literature related to trigeminovagal and oculocardiac reflex covering over 15,000 patients including 51 randomized clinical trials and case reports are analyzed and reviewed. Under an ongoing observational trial in Alaska, anesthetic, patient and surgical influences on routine strabismus surgery using prospective, uniform EOM tension are compared seeking sufficient sample size to characterize this individually widely variable cardiac response.

RESULTS

With adequate sample size, and emphasizing clinical studies controlling type of EOM, muscle tension amount and duration, anticholinergic and opioid medications, the following augment OCR; rapid-acting opioids and dexmedetomidine while OCR is reduced in older patients, the right eye, less EOM tension, deeper inhaled agents, hypocarbia, anticholinergic medications and orbital block. In re-operations, the former are relatively poor predictors of subsequent OCR.

CONCLUSION

Profound bradycardia can occur in almost 10% of strabismus surgery cases without anticholinergic preventive measures, but reliable prediction of OCR remains elusive. With foreknowledge and careful anesthetic monitoring of the patient before EOM manipulation, residual adverse sequelae from OCR are fortunately very rare. Despite well over a century of experience, the teleology for this occasionally dramatic cardiac response to eye surgery is still not known.

Preemptive analgesia in rhegmatogenous retinal detachment surgery: is it effective?

PURPOSE

To evaluate the efficacy of preemptive analgesia in surgical repair of retinal detachment (RD) using scleral buckle and cryopexy under general anesthesia.

METHODS

Thirty patients who were scheduled for rhegmatogenous RD surgical repair using scleral buckle and cryopexy and who were American Society of Anesthesiologists physical status I, II, or III were included in this study. The patients were randomly divided into two equal groups. The surgery was done under general anesthesia in both groups, but in Group 2, sub-Tenon anesthesia was given as preemptive analgesia after induction anesthesia and before start of surgery. Both groups were statistically comparable as regards patient age and weight and duration of anesthesia and surgery.

RESULTS

The incidences of intraoperative oculocardiac reflex and postoperative vomiting were significantly lower in Group 2 compared with Group 1 (P < 0.001 and 0.0113, respectively). The time of first postoperative analgesic dose was significantly shorter in Group 1 (46.67 +/- 18.84 minutes) compared with Group 2 (162.67 +/- 29.391 minutes) (P < 0.001). The total analgesic consumption per 24 hours was significantly higher in Group 1 compared with Group 2 (P < 0.001). The time of discharge from the hospital was significantly shorter in Group 2 (8.8 +/- 2.704 hours) compared with Group 1 (12.4 +/- 3.481 hours) (P = 0.0018).

CONCLUSION

The use of sub-Tenon block as preemptive analgesia after induction of general anesthesia and before the start of rhegmatogenous RD surgical repair was effective in reducing postoperative pain and analgesic requirements compared with an unblocked group. The use of sub-Tenon block was also effective in reducing intraoperative incidence of oculocardiac reflex and postoperative incidence of vomiting.