Low incidence of the oculocardiac reflex and postoperative nausea and vomiting in adults undergoing strabismus surgery

Purpose: To investigate the incidence of the oculocardiac (OCR), and of postoperative nausea and vomiting (PONV) in adults undergoing strabismus surgery. Methods: Adults (18-86 yr) undergoing strabismus surgery received 10 mu g.kg(-1) atropine and 10 mu g.kg(-1) alfentanil iv and were randomly allocated to: (A) 5 mg.kg(-1) thiopentne iv, isoflurane/N2O maintenance; (B) 3 mg.kg(-1) propofol iv, propofol/N2O maintenance (10-14 mg.kg(-1).hr(-1)); (C) 3 mg.kg(-1) propofol iv, propofol/air/O-2 maintenance (10-14 mg.kg(-1).hr(-1)). Analyses were with the number-needed-to-treat/harm. Results: In 97 adults the absolute risk of OCR (13-20%) and PONV (21-31% after 24 hr) was low, with no differences between groups. Number-needed-to-treat to prevent PONV with propofol with or without N2O compared with thiopentone-isoflurane was 7 to 11. Number-needed-to-harm for one OCR with propofol compared with thiopentone-isoflurane was 17. Conclusion: Adults undergoing strabismus surgery with prophylactic atropine had a low risk of OCR and PONV, independent of the anaesthetic technique used.