Preoperative Fasting Before Interventional Techniques: Is It Necessary or Evidence-Based?

Background: Interventional pain management is an evolving specialty. Multiple issues including preoperative fasting, sedation, and infection control have not been well investigated and addressed. Based on the necessity for sedation and also the adverse events related to interventional techniques, preoperative fasting is considered practical to avoid postoperative nausea and vomiting. However, there are no guidelines for interventional techniques for sedation or fasting. Most interventional techniques are performed under intravenous or conscious sedation. Objective: To assess the need for preoperative fasting and risks without fasting in patients undergoing interventional techniques. Study Design: A prospective, non-randomized study of patients undergoing interventional techniques from May 2008 to December 2009. Study Setting: An interventional pain management practice, a specialty referral center, a private practice setting in the United States. Methods: All patients presenting for interventional techniques from May 2008 to December 2009 are included with documentation of various complications related to interventional techniques including nausea and vomiting. Results: From May 2008 to December 2009 a total of 3,179 patients underwent 12,000 encounters with 18,472 procedures, with patients receiving sedation during 11,856 encounters. Only 189, or 1.6% of the patients complained of nausea and 3 of them, or 0.02%, experienced vomiting. There were no aspirations. Of the 189 patients with nausea, 80 of them improved significantly prior to discharge without further complaints. Overall, 109 patients, or 0.9% were minimally nauseated prior to discharge. The postoperative complaints of continued nausea were reported in only 26 patients for 6 to 72 hours. There were only 2 events of respiratory depression, which were managed with brief oxygenation with mask without any adverse consequence of nausea, vomiting, aspiration, or other adverse effects. Limitations: Limitations include the nonrandomized observational nature of the study. Conclusion: This study illustrates that postoperative nausea, vomiting, and respiratory depression are extremely rare and aspiration is almost nonexistent, despite almost all of the patients receiving sedation and without preoperative fasting prior to provision of the interventional techniques. Key words: Interventional pain management, interventional techniques, complications, relative risk, evidence-based medicine, preoperative fasting, nausea, vomiting, aspiration