[Blocking nociceptive afferents by retrobulbar bupivacaine does not decrease nausea and vomiting after propofol-remifentanil anaesthesia]

Abstract

To test whether prophylactic neural blockade of noziceptive afferents or antiemetics diminutes postoperative nausea and vomiting (PONV) we studied in a randomised, prospective, and ouble-blind fashion 102 patients receiving implantation of an episcleral radioactive applicator for treatment of ocular malignant melanoma during remifentanil-propofol-anaesthesia.

Methods: 15 minutes prior to induction Dolasetron 12.5 mg (n = 18) or 50 mg (n = 20), Ondansetron 8 mg (n = 18), Droperidol 20 microg/kg (n = 23) or NaCl 0.9 % (n = 22) were randomly injected i.v. Furthermore, 4-8 ml Mepivacain 2 %/Bupivacain 0.5 % (n = 52) or saline (n = 50) were injected into the retrobulbar space after anaesthetic induction. Piritramid (0.1 mg/kg) was given for postoperative analgesia 30 minutes before end of surgery. Metamizol (1 g i.v.) and Dolasetron (12.5 mg i.v.) were provided on request as "rescue" medications. Variables were assessed by standardised questioning (NRS; yes/no) before and 1, 6, and 24 hours after surgery.

Statistics: Chi(2)-, Mann-Whitney-U-, Kruskal-Wallis-test and logistic regression analysis, p < 0.05.

Results: Although retrobulbar anaesthesia decreased ocular pain (p = 0.013) and total postoperative complaints (p = 0.017) the incidence of PONV was not diminished. Droperidol was the only antiemetic to decrease PONV significantly (p = 0.001).

Conclusions: Although prophylactic blockade of nozizeptive afferents by retrobulbar anesthesia decreased ocular pain and postoperative complaints, it failed to decrease the incidence of PONV. Thus, PONV after ocular surgery under propofol-remifentanil anaesthesia is not attenuated by preoperative blockade of noziceptive afferents. In patients undergoing total intravenous anaesthesia with propofol-remifentanil, droperidol prevented PONV more effectively than the used serotonin receptor antagonists.