The oculocardiac reflex during strabismus surgery: its relationship to preoperative clinical eye findings and subsequent postoperative emesis.
OBJECTIVE
To compare the occurrence of significant bradycardia due to the oculocardiac reflex (OCR) during strabismus surgery and its relationship to preoperative clinical eye findings and subsequent development of postoperative emesis.


METHODS
The medical records of consecutive patients who underwent strabismus surgery August 2006 to June 2009 were retrospectively reviewed. OCR was defined as presence of dysrhythmia or a sudden heart rate decrease ≥ 20% after traction on the extraocular muscle. OCR incidence was compared between the first, second, and third (if any) extraocular muscles in patients who had multiple-muscle strabismus surgery and also between specific muscles (eg, medial rectus vs lateral rectus muscle). Associations with OCR were compared for different strabismus types. Vomiting was considered postoperative if it occurred before discharge of the patient at noon on the day following surgery. Risk factors for OCR and postoperative vomiting were evaluated by logistic regression analysis.


RESULTS
A total of 111 records were reviewed; 41 patients (37%) experienced OCR. Incidence of OCR and absence of OCR during traction of the first muscle were significantly associated with events during traction of the second (χ(2) = 36.681, P < 0.001) and third muscles (Fisher exact test, P = 0.030). The best predictors of OCR were the absence of fine stereopsis and a larger number of surgically treated muscles. Of the 111 patients, 30 (27%) who had postoperative vomiting, the best predictors were female sex and young age.


CONCLUSIONS
In our cohort, patients experiencing intraoperative OCR when the first extraocular muscle was manipulated during multiple-muscle strabismus surgery were likely to experience it again during traction of additional muscles. More severe postoperative vomiting was common in these patients. OCR was associated with the preoperative absence of fine stereopsis.
Department of Ophthalmology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Ophthalmology, Kaohsiung Municipal Hsiao-Kang Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Ophthalmology, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
Yu-Hung
YH
Lai
School of Nursing, College of Nursing, Kaohsiung Medical University, Kaohsiung, Taiwan.
Hsin-Tien
HT
Hsu
Department of Ophthalmology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Ophthalmology, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
Hwei-Zu
HZ
Wang
Department of Anesthesiology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan. Electronic address: yuhula@kmu.edu.tw.
Kuang-I
KI
Cheng
Department of Ophthalmology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Ophthalmology, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
Kwou-Yeung
KY
Wu
D000293:Adolescent; D000328:Adult; D000772:Anesthesia, Local / Q000379:methods; D001919:Bradycardia / Q000209:etiology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007431:Intraoperative Complications; D008297:Male; D008875:Middle Aged; D009801:Oculomotor Muscles / Q000601:surgery*; D013508:Ophthalmologic Surgical Procedures / Q000009:adverse effects*; D020250:Postoperative Nausea and Vomiting; D012024:Reflex, Oculocardiac; D012189:Retrospective Studies; D012307:Risk Factors; D013285:Strabismus / Q000601:surgery*; D055815:Young Adult