Dataset Information

The Oculocardiac Reflex: A Review.

ABSTRACT:

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.

SUBMITTER: Arnold RW

PROVIDER: S-EPMC8238553 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:BackgroundThe oculocardiac reflex (OCR), bradycardia that occurs during strabismus surgery is a type of trigemino-cardiac reflex (TCR) is blocked by anticholinergics and enhanced by opioids and dexmedetomidine. Two recent studies suggest that deeper inhalational anesthesia monitored by BIS protects against OCR; we wondered if our data correlated similarly.MethodsIn an ongoing, prospective study of OCR/TCR elicited by 10-s, 200 g 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.ResultsFrom 1992 through 2013, 2833 cases of OCR during strabismus surgery were monitored. Excluding re-operations and cases with anticholinergic, OCR from first EOM traction averaged - 20.2 ± 21.8% (S.D.) with a range from - 95 to + 25% in patients aged 0.2 to 90 (median 6.5) years. We did not find correlation between %OCR and brain wave for 97 patients with BIS monitoring and 91 with Narcotrend. With intra-patient controls between first and second muscle, the difference in brain wave did not correlate with difference in %OCR for BIS (r = 0.0002, 95% C. I -0.0002, 0.002, p = 0.30) or for Narcotrend (r = - 0.001, 95% C. I -0.004, 0.001, p = 0.32). Secondary multi-variable analysis demonstrated significant association on %OCR particularly with BIS monitor, opioid, propofol and nitrous oxide concentration in the second EOM tensioned. Sevoflurane concentration correlated better with BIS monitor in second and third EOM tension. %OCR correlated with younger age (p < 0.01). OCR with rapid onset was more profound than those with gradual onset (difference in means 18, 95% C. I 10, 26%).ConclusionsWe were unable to confirm a direct correlation between brain wave monitor and OCR when using multifactorial anesthetic agents. The discrepency with other studies probably reflects direct impact of inhalational agent concentration and less deliberate quantification of EOM tension. We found no level of BIS or Entropy EEG monitoring that uniformly prevents OCR.Trial registryNCT03663413.Datahttp://www.abcd-vision.org/OCR/OCR%20Brainwave%20de-identified.pdf .

Project description:IntroductionOphthalmic surgery is assumed to be safe, but some operations require general anaesthesia which is associated with a number of potential complications. In addition, adverse cardiovascular symptoms, such as severe slowing of the heart rate and, in some cases, cardiac arrest may occur due to the surgical technique. The aim of this study was to determine whether it is possible to predict the occurrence of oculocardiac reflex (OCR) based on heart rate variability (HRV) analysis for autonomic nervous system (ANS) activity assessment measured prior to the induction of anaesthesia and immediately before eyeball traction.MethodsFifty-two adults of both sexes (age range 18-65 years) with American Society of Anesthesiologists (ASA) physical status class 1 and 2 were enrolled in this study. All patients had underwent episcleral buckling under general anaesthesia. High-frequency (HF) changes in HRV are thought to reflect parasympathetic impulse transmission, whereas low-frequency (LF) changes reflect both sympathetic and parasympathetic activity. However, in practice, LF changes can be considered to reflect sympathetic changes. Thus, the LF/HF ratio reflects the actual balance between sympathetic and parasympathetic activity. Based on that, frequency domain HRV parameters from 5-min Holter electrocardiogram recordings before anaesthesia induction and before eyeball traction were used for the analysis. The statistical analysis also included patient age, sex, ASA status and preanaesthesia and premanoeuvre heart rate and blood pressure.ResultsData from 42 patients were analysed. Oculocardiac reflex was observed in 32 patients (76.2%). No difference was found in the analysed parameters between patients with and without oculocardiac reflex. There was no relationship between the incidence of the OCR and the analysed parameters.ConclusionThe prediction of OCR based on initial ANS tone was not possible, and the initial heart rate, blood pressure, age, sex, and ASA status were not helpful for the identification of patients at risk of this reflex.Trial registrationClinicalTrials.gov identifier no.: NCT01714362.