Prevención de náuseas y vómitos postoperatorios

Las náuseas y vómitos son muy molestos para el paciente en el postoperatorio inmediato, sin olvidar el riesgo siempre presente de aspiración ante la presencia de vómito. Un estudio prospectivo reciente realizado en Chile y publicado en la Révista Médica de Chile compara los efectos de dexametasona, droperidol y ondansetrón en este grupo de pacientes. Les doy la dirección al artículo en español y formato pdf que se encuentra a libre acceso en Scielo.
Además, coloco el resumen de un artículo similar publicado en el NEJM.

http://www.scielo.cl/pdf/rmc/v134n6/art04.pdf
Eficacia de la dexametasona en el tratamiento agudo de náuseas y vómitos posoperatorios: Comparación con droperidol y ondansetrón.
MUNOZ, Hernán R, IBACACHE, Mauricio E y MERTZ, Verónica F.
Rev. méd. Chile, jun. 2006, vol.134, no.6, p.697-702. ISSN 0034-9887.

Background: Dexamethasone is useful as prophylaxis for postoperative nausea and vomiting (PONV).
Aim: To study the short term efficacy of dexamethasone to treat PONV in adults without prophylaxis, and compare its efficacy with that of droperidol and ondansetron.
Material and methods: A prospective study was performed with 120 consecutive adult patients presenting PONV in the postanesthesia care unit (PACU) at a University teaching hospital. During the occurrence of PONV, patients were randomized to receive in a double blind manner dexamethasone 8 mg IV (Group 1, n=40), droperidol 1.25 mg IV (Group 2, n=40), or ondansetron 2 mg IV (Group 3, n=40). Risk factors for PONV were recorded. Evaluations were made until discharge from the PACU and included presence of PONV, degree of sedation, and other potential adverse effects of the study drugs. Short term efficacy was defined as the percentage of patients free of PONV during all the stay in PACU after treatment.
Results: General data was similar for the 3 groups. Mean ± SD stay in PACU after treatment was 101±34 minutes in Group 1, 93±33 minutes in Group 2, and 99±32 minutes in Group 3 (NS). Short term efficacy (CI 95%) was 55% (40-70%) in Group 1, 90% (81-99%) in Group 2, and 63% (48-78%) in Group 3 (p <0.05>Conclusions: Short term efficacy of dexamethasone to treat PONV was similar to ondansetron, but inferior to droperidol. Further studies are needed to define the duration of this effect of dexamethasone.

A Factorial Trial of Six Interventions for the Prevention of Postoperative Nausea and Vomiting
Christian C. Apfel, M.D., Kari Korttila, F.R.C.A., Ph.D., Mona Abdalla, Ph.D., Heinz Kerger, M.D., Alparslan Turan, M.D., Ina Vedder, M.D., Carmen Zernak, M.D., Klaus Danner, M.D., Ritva Jokela, M.D., Ph.D., Stuart J. Pocock, Ph.D., Stefan Trenkler, M.D., Markus Kredel, M.D., Andreas Biedler, M.D., Daniel I. Sessler, M.D., Norbert Roewer, M.D., for the IMPACT Investigators
N Engl J Med 1994; 350(24):2441-2451
ABSTRACT
Background Untreated, one third of patients who undergo surgery will have postoperative nausea and vomiting. Although many trials have been conducted, the relative benefits of prophylactic antiemetic interventions given alone or in combination remain unknown.
Methods We enrolled 5199 patients at high risk for postoperative nausea and vomiting in a randomized, controlled trial of factorial design that was powered to evaluate interactions among as many as three antiemetic interventions. Of these patients, 4123 were randomly assigned to 1 of 64 possible combinations of six prophylactic interventions: 4 mg of ondansetron or no ondansetron; 4 mg of dexamethasone or no dexamethasone; 1.25 mg of droperidol or no droperidol; propofol or a volatile anesthetic; nitrogen or nitrous oxide; and remifentanil or fentanyl. The remaining patients were randomly assigned with respect to the first four interventions. The primary outcome was nausea and vomiting within 24 hours after surgery, which was evaluated blindly.
Results Ondansetron, dexamethasone, and droperidol each reduced the risk of postoperative nausea and vomiting by about 26 percent. Propofol reduced the risk by 19 percent, and nitrogen by 12 percent; the risk reduction with both of these agents (i.e., total intravenous anesthesia) was thus similar to that observed with each of the antiemetics. All the interventions acted independently of one another and independently of the patients' baseline risk. Consequently, the relative risks associated with the combined interventions could be estimated by multiplying the relative risks associated with each intervention. Absolute risk reduction, though, was a critical function of patients' baseline risk.
Conclusions Because antiemetic interventions are similarly effective and act independently, the safest or least expensive should be used first. Prophylaxis is rarely warranted in low-risk patients, moderate-risk patients may benefit from a single intervention, and multiple interventions should be reserved for high-risk patients.