© Springer International Publishing Switzerland 2017Basavana G. Goudra and Preet Mohinder Singh (eds.)Out of Operating Room Anesthesia10.1007/978-3-319-39150-2_32
32. Future Research and Directions in Out of Operating Room Anesthesia
Department of Anesthesiology and Critical Care Medicine, Hospital of the University of Pennsylvania, 3400 Spruce Street,5042 Silverstein Building, Philadelphia, PA 19104, USA
Department of Anesthesiology, Critical Care and Pain Medicine, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, Delhi, 110029, India
The traditional surgeries are declining and with that the role of surgeons. The last decade has seen an unprecedented growth of “procedures” that are threatening to replace many conventional surgeries. More importantly, these procedures have moved to places away from the safe operating rooms. As a result, the role of traditional anesthesiologists will wane and anesthesia providers will be required to learn new skills to face the new challenges. This chapter has examined some of the risks associated with providing deep sedation and anesthesia in out of operating room locations. Airway related adverse events dominate along with fluctuating anesthesia needs. Every location poses unique challenges and no single anesthesia provider will be able to master all the skills necessary. Research and publications are lacking in this area. It is hoped that mainstream anesthesia journals will recognize this area of anesthesia and give its due importance.
Rarely a surgical approach or an interventional procedure is developed to exploit a newly invented anesthesia technique. Traditionally, anesthesia providers have developed innovative ways to render any novel surgery/procedure pain free and acceptable to patients. Pioneering new techniques, whether in the area of drug delivery or device development, have helped the growth of surgical and non-surgical specialties. For example, extensive use of propofol in endoscopy sedation popularized screening colonoscopy. Similarly, application of jet ventilation in electrophysiological procedures has rendered the procedural conditions more favorable to interventional cardiologists. Many soft drugs are in the making and these sedative/hypnotics will be looking for an appropriate “home”. Although Sedasys® is dead, the idea of computer assisted personalized sedation (CAPS) is very much alive.
In order to foresee future anesthetic challenges in the area of out of operating room anesthesia (OORA), it is essential to focus on the current developments in related fields. Additionally, the existing anesthetic challenges in out of operating room locations are far from resolved and need consideration. Some of the challenges facing OORA are related to patent safety while others are related to its practice.
Patient Safety and Outcome
Hypoxemia and associated adverse events continue to dominate OORA practice. An often mentioned study in relation to OORA practice is that of Metzner et al. She analyzed the American Society of Anesthesiologists Closed Claims database and specifically studied the pattern of injury associated with OORA practice . An important finding was, that 50 % of the claims from remote locations involved monitored anesthesia care. There were more deaths in remote locations compared to those arising from operating room practice. Respiratory adverse outcomes dominated out of operating room location claims. Moreover, oxygenation/ventilation related events were the most common. Most notably, remote location claims were frequently judged as preventable by better monitoring.
The findings of our own study published in Nov 2015 were no different . In this single center retrospective analysis of 73,029 gastrointestinal (GI) endoscopic procedures, the incidence of cardiac arrest and death (all causes, until discharge) was 6.07 and 4.28 per 10,000 in patients sedated with propofol. This was in comparison to non–propofol‑based sedation where the incidence was 0.67 and 0.44 for cardiac arrest and death respectively. The incidence of cardiac arrest during and immediately after the procedure (in the recovery area) for all endoscopies was 3.92 per 10,000, of which 72 % were airway management related. In this study, about 90.0 % of all peri‑procedural cardiac arrests occurred in patients who received propofol. Additionally, even non-cardiac arrest adverse events were more likely to occur in patients who received propofol sedation . The latest addition to the reports of propofol related adverse events is the study of Wernli et al. [4, 5]. This study involving patients undergoing colonoscopy concluded, that propofol sedation is associated with a 13 % increase in all complications.
Adverse events like air embolism leading to death are reported during procedures such as endoscopic retrograde cholangiopancreatography (ERCP) and has been a subject of recent research [6–8]. Selected patients might benefit from the use of doppler ultrasound to detect any ERCP related air embolus. It was recently reported that ineffective sedation and unnecessary patient movements might contribute to poorer therapeutic outcomes in patients undergoing advanced endoscopic procedures [9, 10]. In this study, the authors investigated the impact of anesthesia and deep sedation on the efficacy of esophageal radiofrequency ablation (RFA) procedures. They found a high frequency of sedation related adverse events (SRAEs) in patients receiving both general endotracheal anesthesia (GET) and deep sedation. However, they also found an association between the occurrence of SRAE and the number of RFAs needed to achieve complete eradication of dysplasia. This study highlights the important role of anesthesia providers in OORA. Not only do our actions improve the patent comfort, they can impact the therapeutic outcome.
Newer procedures like peroral endoscopic myotomy (POEM) are getting popular. Standardization of anesthesia practice during such procedures is important. Failure of standardization might contribute to adverse events like pulmonary aspiration . Organizations like American Society of anesthesiologists (ASA) and the European Society of Anesthesiologists (ESA) should take a lead role in designing evidence based guidelines for OORA practice.
In summary, respiratory and cardiovascular complications remain a significant factor in patients receiving anesthesia in out of OR locations. Tackling these issues will be a challenge for researchers. Developments of new airway devices and drugs are steps in the right direction [12–15]. Initial results with remimazolam, a new short acting benzodiazepine with a fixed context sensitive half-life are encouraging [16, 17]. It remains to be seen if the drug can keep its initial promise. In our opinion, remimazolam has kinetics that are better suited for intensive care unit (ICU) sedation or as a hypnotic component of total intravenous anesthesia (TIVA), than for GI endoscopy.
Non-anesthesia Providers and Propofol
Administration of propofol by non-anesthesia providers is a very controversial area. We published a meta-analysis reporting the safety of propofol in the hands of non-anesthesia providers . In this study, we compared the safety of propofol sedation in patients who underwent advanced endoscopic procedures. Propofol was administered by either anesthesia providers (AAP) or non-anesthesia providers (NAAP). NAAP were predominantly registered nurses who worked under the supervision of gastroenterologists. After analyzing a total of 3018 and 2374 patients from twenty-six studies in each group (16 NAAP and 10 AAP, respectively), the meta-analysis found a significantly higher incidence of hypoxia (oxygen saturation less than 90 %) and airway intervention rates in the AAP group. However, both patient and endoscopist satisfaction rates were lower in the NAAP group. A higher mean dose of propofol administered by the anesthesia providers was the most likely explanation. This might have contributed to both better satisfaction as well as higher sedation-related adverse event rates.
Cost and Efficiency
With the rising cost of US health care, it has become imperative to demonstrate that anesthesia providers not only provide safe sedation, but also bring value for money. Questions have been raised about the value of anesthesia providers in endoscopy suites [19–21]. The most common justification for extensive use of propofol in screening colonoscopy relates to patient acceptability. The patient satisfaction is unquestionably higher with propofol sedation. The success of any national screening program is determined by its uptake. Without public participation, such programs are likely to fail. Fear of discomfort is likely to keep away many of these patients. Considering that the incidence of colonic cancer is demonstrably less since the advent of screening colonoscopy, an argument can be made for propofol use in all the patients. In spite of added sedation risks, the overall gains might swing the balance. Even in relation to cost, the savings in terms of cancer treatment might offset any propofol administration related expenses. Additionally, the burden of dealing with cancer in the family, both financial and psychological cannot be overlooked. The increased efficiency that can be achieved with propofol is another important factor. However, there is no evidence to prove any of these assumptions. A large prospective randomized trial is might answer most of these questions.
Having a competent group of dedicated anesthesia providers is demonstrated to improve the outcome during the ERCP (Endoscopic Retrograde Cholangiopancreatography) anesthesia . In this single center study of 1167 ERCP procedures, 653 (56 %) were assisted by regular and 514 (44 %) by non-regular anesthesia consultants. Across all American Society of Anesthesiologists (ASA) grades, regular anesthesiologists provided safer and more efficient care than non-regular anesthesiologists (overall mean anesthesia time of 24.82 ± 12.96 versus 48.63 ± 21.53 min). Safety was established by higher mean oxygen saturations and in the regular anesthesiologists group. This was in spite of the fact that regular anesthesiologists tended to intubate these patients more frequently. Monetarily, if all the procedures were to be performed by regular anesthesiologists, the hospital could have saved US $758536.00 over the 2 years. This savings was from ERCP associated anesthesia costs alone. As a result, it is important to consider the use of appropriately trained and dedicated anesthesia providers in OORA practice. These findings are important for manpower planning in any large endoscopy center.