Anesthesia and sedation outside the operating room

ACO/200228; Total nos of Pages: 7;

ACO 200228

Anesthesia and sedation outside the operating room: how to prevent risk and maintain good quality Claudio Melloni

Purpose of review The purpose of this review is to define risks for anesthesia and sedation outside the operating room, and to suggest how to prevent these risks and maintain quality of care. Recent findings There are no recent data on risk for anesthesia outside the operating room, except information derived from the American Society of Anesthesia Closed Claims project, which indicates there is a higher risk for office-based anesthesia. Summary Complications of anaesthesia outside the operating room are not well studied, although a few closed claims are appearing in the literature suggesting there is a higher risk. Topics discussed focus on MRI and surgical procedures, principally dental, plastic, and gastrointestinal endoscopy. Risk factors for these procedures are identified and quantified and measures to reduce them discussed, with emphasis on full oxygenation and end-tidal carbon dioxide monitoring. Nonoperating room anesthesia requires skills, experience and organization. Quality can only be assured by ensuring all alternative locations adhere to operating room standards. Keywords complications, liability, morbidity, mortality, nonoperating room anesthesia, office-based anesthesia, risk management Curr Opin Anaesthesiol 20:000–000. ß 2007 Lippincott Williams & Wilkins. Consultant Anesthesist, Villa Torri Private Hospital, Bologna, Italy Correspondence to C. Melloni, via Fossolo 28, 40138 Bologna, Italy Tel: +39 0513 90048; fax: +39 0513 05034; e-mail: [email protected] Current Opinion in Anaesthesiology 2007, 20:000–000 Abbreviations GA NORA

general anesthesia nonoperating room anesthesia

ß 2007 Lippincott Williams & Wilkins 0952-7907

Introduction Identifying the risks in anesthesia means preventing adverse outcomes and minimizing their impact when they occur. The most common events in anesthesia leading to injury were found to be respiratory [1]. A recent report [2], however, suggests that cardiovascular events actually represent the majority of complications. While risks and complications of operating room anesthesia have been defined leading to measures able to minimize them [3], data on complications induced by nonoperating room anesthesia (NORA) are scarce. Even a monumental task such as the National Confidential Enquiry into perioperative deaths (UK) [4] did not distinguish between accidents occurring within or outside the operating room. The American Society of Anesthesia (ASA)-sponsored Closed Claims analysis [5] only recently began to examine the litigation from office-based anesthesia, concluding that the injury severity was greater than for other ambulatory anesthesia claims. As NORA may not follow the same patterns of complications as operating room anesthesia, statistics validated in the operating room do not necessarily apply outside. It is therefore of paramount importance to define the risks of performing anesthesia outside the operating room. Our discussion will encompass a few topics and be limited to major morbidity and mortality.

Radiology: MRI and computerized axial tomography scanning Thirty-three cardiorespiratory arrests with 11 deaths were reported in 2 045 954 patients undergoing MRI [6], giving a complication rate of 16.1 per 1 000 000, that is 5.3 deaths per 1 000 000 MRI procedures. Three hundred patients undergoing MRI per year received sedation, but distinguishing between deaths in sedated and nonsedated patients was not possible. Anesthesia or sedation is needed because patients should not move during examination. All uncooperative patients should be anesthetized, but anesthesia services and equipment are scarce in MRI centers [7]. Since MRI is a highly expensive technique, procedure prolongation through poor quality imaging due to movement artifacts should be avoided. Aborted procedures are costly, as well as inconvenient for the patient, who would need to undergo repeat imaging under general anesthesia (GA). Consequently, the cost/efficacy of the anesthetic technique, and the 1


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failure rate, should be considered. The failure rate for chloral hydrate is less than 5% [8,9], but even in the absence of failures [10], prolonged sedation and emesis take their toll and severe desaturation or adverse respiratory events have been noted [11]. Increasing chloral hydrate syrup dosage to 100 mg/kg [12] was found to increase the success rate but led to an incidence of adverse reactions of 21%. The efficiency of the procedure depends on the interval from drug administration to scanning and emergence quality: chloral hydrate needs time to act, and postdischarge side effects can be disturbing, when not serious [13], with a high percentage of prolonged sleepiness, almost 70% unsteadiness, hyperactivity, poor appetite and vomiting. Benzodiazepines [14,15] and barbiturates [16–18] do not rate any better. Propofol requires a learning curve [19] and experience, but offers short recovery times [20,21] and good mental discharge. To avoid involuntary movements dosage should be in the range of 100 mg/kg/min, corresponding to a target controlled infusion level of around 2 mg/ml [22]. An airway is needed in 20% of cases because of respiratory depression, tracheal intubation being rarely required [23]; simple manoeuvres like chin lift help to maintain the airway [24]. The higher cost of the drug is largely compensated by savings in postanesthesia recovery and nursing times, with faster turnover rates [25,26]. Imaging quality is better with spontaneous breathing under pentobarbital sedation than with intermittent positive-pressure ventilation/GA, which may lead to atelectasis obscuring small pulmonary metastasis [27]. Five centimeters of positive end-expiratory pressure (PEEP) completely prevents GA-induced atelectasis in children [28].

permanent neurological injury, 12 occurred at home or during transit [30].

Dental office Approximately 300 000 patients per year undergo GA for minor dental procedures in the UK [31]. In deaths occurring on the dental chair (26 between 1984 and 1993) following cardiorespiratory failure, the postmortems did not clarify the cause of cardiac arrest [32]. A mortality rate of nine in 1 000 000 was reported following administration of oxygen/nitrous oxide/halothane [33]. The number of deaths in the UK, however, has decreased from 100 (1970–79) to 20 (1990–99) [34,35]. Inappropriate patient selection (ASA 3) may have contributed to anesthetic complications [36], but deaths in young healthy patients have also been described [37]; overall, care was judged to be poor. The incidence of mortality in GA perfomed for dentistry procedures has decreased in the latest reviews to 1–1.5 cases per million [38].

Pediatric sedation Exploring ‘sentinel events’ – that is events that, if left untreated, may progress to major accidents – is crucial for prevention. These events include hypoxemia, hypoventilation, airway compromise, and unplanned hospital admission. Hypoxemia was reported in 0.8–9% of children sedated for MRI and computed tomography (CT) [10,15,39–42], and airway compromise was reported in 1.3–6% [43–45]. Unscheduled hospital admission ranged from 0.03 to 0.07% [46]. Nitrous oxide added to chloral hydrate increases hypoventilation from 70% to almost 100% of patients, transferring them from consciousness to deep sedation [47].

Therapeutic endoscopy The literature [29] and our experience have led to the conclusion that, with the proper equipment, GA offers a safer and time-effective way to provide conditions for high-quality scans, accompanied by quick recovery. The radiology department is probably the most demanding area for anesthesia; their needs vary from resuscitation of cranial disasters to monitored anesthesia care. The main problems arise from irradiation and contrast media reactions; complexity and demands also stem from interactions with other specialists, such as gastroenterologists and cardiologists. Since sedation needs time to take effect, anxyolitics and sedatives may be given before transferring the patient to the procedural area. Among 118 serious adverse events following premedication in children, including death and

The overall complication rate for upper gastrointestinal endoscopy is 0.13–0.08%, with a mortality of 0.7–1 per 10 000. Cardiorespiratory problems account for half of complications and 65% of deaths [48]. Most patients receive sedation [49] with midazolam, diazepam and, more recently, propofol. Intra and postprocedure occurrences are strictly linked [50]; 69% of patients experience occurrences both during the procedure and the in-hospital stay. The most common intraoperative complaints were pain, hypertension, hypotension, bradycardia and oxygen desaturation, while hypotension, weakness, abdominal discomfort and dizziness followed the procedure in over 25% of cases. Sentinel events in gastrointestinal endoscopy were arterial desaturation, ranging from 0.4% with oxygen to 70% without, and tachycardia (30–40%). Cardiac arrhythmias


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occurred in 36% of patients with cardiopathy, 25% with pneumopathy and 16% for apparently healthy individuals [51].

cases, unplanned intubations in 8%, local anesthetic intravascular injection in 3% and there was 1% mortality. Anesthesiologist attendance was rare.

Risk factors for adverse outcomes in endoscopy with conscious sedation have been identified [52,53]. Topical oropharingeal or nasal anesthesia is considered to be absolutely safe but, besides methemoglobinemia [54], significantly increases obstructive and central apnea [55].

Mortality following liposuction averaged 19.1 per 100 000 (one in 5000) [67], pulmonary embolism being the most frequent killer [68].

The above considerations imply that patients, especially if premedicated, should receive supplementary oxygen [56], since arterial oxygen saturation in ambient air very often ranges from around 89% to 92% after premedication alone, and further declines during endoscopy and benzodiazepine plus opioid administration. In children, GA with oxygen/nitrous oxide/halothane plus intubation ensures higher oxygen saturation than midazolam sedation after topical anesthesia [57]. Pharynx obstruction, tracheal compression, gastric distention, drugs, and local anesthesia contribute to oxygen desaturation during esophagoduodenoscopy. Sedation for diagnostic endoscopy is recommended for ethical and physiological reasons, since sedation and analgesia at least partially counteract the procedure-induced rise in cathecolamines, responsible for hypertension and arrhythmias [58]. Complications following endoscopy relate to team experience, with some centers presenting excellent results [59] even in extremely old patients [60]. Capnography is most useful during and even after endoscopy, as it may identify hypoventilation and apnea that may not emerge during supplemental oxygenation [61]. The National Confidential Enquiry into perioperative deaths (UK) [62] examined 1818 inpatient deaths within 30 days from gastrointestinal therapeutic endoscopy procedures. Fourteen percent of patients were judged to have received excessive sedation; monitoring was poor in 23% of cases, and care was suboptimal in 27% of patients with upper gastrointestinal bleeding. Thus, the quality of care in these very often elderly and fragile patients needs to be improved.

Office-based anesthesia, with special emphasis on plastic surgery Office-based anesthesia appears to be safe, as a 0.0017% mortality rate (1/57 000) was reported in accredited institutions [63], with better results in the office than in ambulatory centers [64,65]. Greater figures may emerge from nonaccredited centers, however, because plastic surgeons declared in a questionnaire [66] that respiratory arrest occurred in 13% of

Since 320 000–354 000 liposuctions are performed yearly in the USA [69], these data induced the Florida Board of Medicine to declare on 10 August 2000 a 90-day moratorium on office-based surgery because ‘there is an immediate danger to the health welfare and safety of patients’. An analysis of deaths 6 years later [70] revealed 46 cases in more than 600 000 procedures performed in the office. The great majority of these cases were related to nonboard-certified plastic surgeons and specialists in other fields, raising the issue of the credentials of anesthesia providers. The guidelines for qualifications of anesthesia providers have been discussed by the ASA [71], which documents that the door should be left open to other anesthesia providers, like operating physicians or other licensed physicians. The mortality rate in the office is greater than in freestanding centers and hospitals [72]. This contradicts statements (founded on settled insurance liability claims) that office-based liposuction is less risky than hospitalbased procedures, as the latter accounted for 71% of malpractice claims compared with 21% in the office setting [73].

Liability risks NORA claims were found to more frequently involve substandard care (63%) than operating room claims (29%), and may be prevented by better monitoring, Payments made, however, were similar in NORA and operating room claims [74]. NORA claims have increased sixfold over the decades (from 0.2% in the 1970s to 1.2% in the period 1990–2001). Other specialists may be more exposed [75].

Special problems of NORA NORA problems derive from remote locations, limited working space, electrical interference with monitors and phones, lighting and temperature inadequacies, lack of skilled personnel, drugs, and supplies. Noises are unsettling for the patient and disturb the anesthesiologist. As alarm recognition occurs 34% of the time under ideal conditions [76], noisy areas like MRI centers make sound recognition and alarm perception very difficult. A presumed reason is that many alarms have similar sounds [77]. Since alarm volume and recognition rate are correlated, we suggest that alarms be set at maximum levels in NORA environments.


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Inside the operating room every effort is made to access the patient easily; when this is not possible, special equipment and precautions are needed. Bulky equipment may impede access to the patient and warrant airways to be secured even for minor procedures.

sedative and hypnotics titrated to effect, this is not the case, so the ASA published its ‘Practice guidelines for sedation and analgesia by non-anesthesiologists’ [86], which have been endorsed by several scientific colleges and associations.

Anesthesiologist(s) . . . and not only, other consultants as well.

I believe that the main questions are as follows: what would happen when a patient’s condition abruptly changes or the patient moves to another stage of sedation? Who would be responsible for complications? Since every patient may become unstable, every single sedation analgesic given outside the operating room should be done by one anesthesiologist/patient/unit of time, and the anaesthesiologist should be an experienced intensivist should a crisis occur.

The National Confidential Enquiry into perioperative deaths (UK) [62] found that the number of yearly procedures performed by some consultant endoscopists was too low to ensure proficiency and skill. It recommended that competency in endoscopy should be assured by national guidelines. No such recommendations exist for anesthesiologists, however, whose competency is simply assumed by the specialist diploma. NORA requires special skills and attitudes; for instance, among 25 neuroanesthesiologists, only three were found to administer anesthesia with the magnet inside the operating room [78], intrinsically recognizing the need for a higher level of technical skills. Nontechnical skills are also important [79], since NORA also stresses other qualities, like task management, team-working capability and coordination, situation awareness, and decision-making. Since NORA involves special risks and difficulties, anaesthetists that are unsafe due either to a lack of knowledge and skills or old age need to be identified [80,81]. Many centers and countries have adopted the post of ‘sedationist’. In Italy, this task is very often assumed by the physician performing the procedure, but nurses have been more and more involved, with excellent results and enviable safety records [8,14]. The issue of quality of care and outcome has been raised [13], and the cost implications of anesthesia services [82]. Anesthesia is a discipline that requires the constant vigilance of well trained and experienced providers; safety derives from high-level dedicated care, teamwork, and rapid availability of physicians, especially during medical crises. Clinical evidence supports the anesthesiologist-led anesthesia care team as the safest and most cost-effective method of delivering anesthesia. Death and failure to rescue were more frequent when care was not directed by anesthesiologists [83]. The reasons behind nurse rather than physician organizations are likely economic, since nurses cost less [84], are probably more attentive to protocols, and may be more manipulated by economy. The debate [85] will continue for a while, at least in countries where certified registered nurse anesthetists are numerous and well trained. Sedation cannot be restricted to anesthesiologists. Even though practitioners should be able to administer

Patients Patients undergoing NORA may be more ill than those attending an operating room, as most NORA claims involve higher-risk, elderly patients undergoing nonemergency surgery [72]. Preanesthetic preparation is very often done by others, who may not consider the interactions between a patient’s physical condition, medications taken and the effects of anesthesia.

Quality issues Quality improvement should rely on raising the standards of every location where sedation and anesthesia are possible to operating room standards. In the meantime, the following recommendations taken from the ASA guidelines for NORA locations [87] should be followed and implemented. (a) Reliable oxygen source including a backup supply. (b) Adequate and reliable suction. (c) Adequate and reliable scavenging system if anesthetic gases are to be used. (d) Self-inflating resuscitation bag capable of delivering an inspired oxygen fraction (FiO2) of 0.90. (e) Adequate drugs, supplies and equipment for the planned activity. (f) Adequate monitoring equipment to adhere to standards for basic anesthetic monitoring. (g) Sufficient electrical outlets, isolated electric power or electric circuits with ground fault interruption in ‘wet areas’ like cystoscopy, arthroscopy, labor and delivery suites, with access to emergency power supply. (h) Sufficient space for equipment and personnel and transportation. (i) Immediate suitability of an emergency cart with defibrillator, emergency drugs, etc. (j) Reliable two-way communication. (k) Observation of all applicable building and safety codes and facility standards. (l) Appropriate postanesthesia management.


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A reliable source of oxygen adequate for the procedure duration and a backup supply are critical. Virtually all facilities in which anesthesia is administered are equipped with a central gas supply system, at least in the more industrialized countries. Cylinders (E type) are rarely seen on anesthesia machines today; if anesthesia is to be delivered in a location without a central medical gas supply, the anesthesiologist and local personnel must first ensure that an adequate supply of oxygen is available. The gas amount left in the cylinder must be continuously monitored and the cylinder replaced before it is completely empty. As a rule of thumb, an E cylinder of 5 l capacity at a pressure of 200 atm roughly contains 1000 l of oxygen; at a pressure of 135 atm, 660 l, and at 100 atm, 500 l. If 6 l/min are consumed, a full cylinder will last 160 min; if half empty, 80 min. If oxygen is delivered without flowmeters, its consumption is unknown and extra care is recommended.

Equipment in nonoperating room anesthesia Old equipment is often kept in NORA areas, so new anesthesiologists may be unfamiliar with it and machines may no longer meet standards. Since such equipment is not used on a daily basis, it has to be carefully checked before each use and a program of maintenance should be instituted. The same considerations apply for monitors.

How to proceed After carrying out an anesthestic and monitoring equipment check, the anesthetic plan should be followed but the anaesthesiologist should always be prepared for a change in procedure. The few data available do not seem to prefer monitored anesthesia care to GA. Bhananker et al. [88] found the same mortality and morbidity rates during monitored anesthesia care with a greater proportion of respiratory depression after absolute or relative overdose of sedative or opioid drugs. It is my personal opinion that sedation and analgesia with spontaneous respiration requires greater skills and experience than general anesthesia with airway control. Monitored anesthesia care for disabled children is much less expensive in the dental rehabilitation office than GA in the operating room, but more sentinel events have been reported [89]. All data should be obtained during the procedure, especially when the anaesthesiologist is away from the patient; this may require remote monitoring, special extension tubing, among other means. The anaesthesiologist must be prepared for bad surprises, including sudden movement of the patient, allergies, anaphylactic shock, and need for vasopressors.

or postoperative periods [5]; therefore, strict surveillance should be exercised until full recovery. During transportation all the equipment necessary for a safe journey should be at hand. The ideal recovery area should be ‘near’ the location where the patient was treated. The safe solution is to place patients in the postanesthesia care unit (PACU) or recovery room, as for surgical patients.

Measures of outcome Critical incidents may be more frequent in NORA; emergency treatment of airways is paradigmatic [90]. The availability of a difficult intubation cart in the ICU or PACU that can be called upon for rescue would be optimal, but distant locations should have their emergency trolley with a reasonable choice of airways. Since outcome is influenced by care quality [91], specific protocols should be adopted for NORA and personnel organized accordingly. NORA activities require time, which means adequate staffing: consider how many NORA activities should be covered every day. An invitation is being made to schedule fixed days for different tasks in order to organize the anesthesia services.

Conclusion No anesthesia or sedation performed outside the operating room should be considered minor; it requires skill, experience, and organization. Anesthetic needs should be evaluated from a safety point of view. Patient preparation, consent, sedation, analgesia or GA should be performed utilizing the same standards as adopted for the operating room.

References and recommended reading Papers of particular interest, published within the annual period of review, have been highlighted as: of special interest of outstanding interest Additional references related to this topic can also be found in the Current World Literature section in this issue (pp. 000–000). 1

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2

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3

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4

Campling EA, Devlin HB, Hoile RW, Lunn JN. The report of the national confidential enquiry into perioperative deaths 1990. London: Her Majesty’s Stationery Office; 1992.

5

Domino KB. Office-based anesthesia: lessons learned from the closed claims project. ASA Newsletter 2001; 65:9–11; 15.

6

Schiebler M, Kaut-Watson C, Williams DL. Both sedated and critically ill require monitoring during MRI. In Vivo Research 1992–2000.

7

McBrien ME, Winder J, Smyth L. Anaesthesia for magnetic resonance imaging: a survey of current practice in the UK and Ireland. Anaesthesia 2000; 55:737–743.

Postoperative surveillance/transportation Almost all the potentially preventable office-based injuries result from adverse respiratory events in the recovery

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61 Lightdale JR, Goldmann DA, Feldman HA, et al. Microstream capnography improves patient monitoring during moderate sedation: a randomized, controlled trial. Pediatrics 2006; 117:1170–1178. 62 Scoping our practice. London: National Confidential Enquiry into Patient Outcome and Death (NCEPOD); 2004. 63 Morello DC, Colon GA, Fredricks S, et al. Patient safety in accredited office surgical facilities. Plast Reconstr Surg 1997; 99:1496–1500. 64 Warner MA, Shields SE, Chute CG. Major morbidity and mortality within 1 month of ambulatory surgery and anesthesia. JAMA 1993; 270:1437– 1441. 65 Natof HE. Complications associated with ambulatory surgery. JAMA 1980; 244:1116–1118. 66 Courtiss EH, Goldwyn RM, Joffe JM, Hannenberg AA. Anesthetic practices in ambulatory aesthetic surgery. Plast Reconst Surg 1994; 93:792– 801. 67 Keyes GR, Singer R, Iverson RE, et al. Analysis of outpatient surgery center safety using an internet-based quality improvement and peer review program. Plast Reconstr Surg 2004; 113:1760–1770. 68 Reinisch JF, Bresnick SD, Walker JWT, Rosso RF. Deep venous thrombosis and pulmonary embolus after face lift: a study of incidence and prophylaxis. Plastic Reconstr Surg 2001; 107:1570–1575. 69 National plastic surgery statistics. American Society of Plastic Surgeons; 2000–2004. 70 Clayman MA, Seagle BM. Office surgery safety: the myths and truths behind the Florida moratoria: six years of Florida data. Plast Reconstr Surg 2006; 118:777–785.

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71 ASA statements on qualifications of anesthesia providers in the office based setting, approved by ASA House of Delegates 13 October 1999 and last affirmed 2004. http://www.asahq.org/publicationsAnd Services/Standards/29. pdf.2004. 72 Grazer F, deJong RH. Fatal outcomes from liposuction: census survey of cosmetic surgeons. Plast Reconstr Surg 2000; 105:436–446. 73 Coleman WP, Hanke CW, Lillis P, et al. Does the location of the surgery or the specialty of the physician affect malpractice claims in liposuction? Dermatol Surg 1999; 25:343–347. 74 Robbertze R, Posner KL, Domino KB. Closed claims review of anesthesia for procedures outside the operating room. Curr Opin Anaesthesiol 2006; 19:436–442. Excellent review of the topic, highlighting the risks coming from the gastrointestinal suite, MRI, computed tomography, angiography and cardiology.

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79 Fletcher G, Flin R, McGeorge P, et al. Anaesthetists’ Non-Technical Skills (ANTS): evaluation of a behavioural marker system. Br J Anaesth 2003; 90:580–588. 80 Atkinson RS. The problem of the unsafe anaesthetist. Br J Anaesth 1994; 73:29–30. 81 Katz JD. Issues of concern for the aging anasthesiologist. Anesth Analg 2001; 92:1487–1492. 82 Abenstein JP, Warner MA. Anesthesia providers, patient outcomes, and costs. Anesth Analg 1996; 82:1273–1283. 83 Silber JH, Kennedy SK, Even-Shoshan O, et al. Anesthesiologist direction and patient outcomes. Anesthesiology 2000; 93:152–163. 84 Cromwell J, Snyder K. Alternative cost-effective anesthesia care t eams. Nurs Econ 2000; 18:185–193. 85 Martin-Sheridan D, Wing P. Anesthesia providers, patient outcomes, and costs: a critique. AANA J 1996; 64:528–534. 86 ASA practice guidelines for sedation and analgesia by non-anesthesiologists. American Society of Anesthesiologists Task Force on Sedation and Analgesia by Non-Anesthesiologists. Anesthesiology 2002; 96:1004–1017. 87 ASA guidelines for non operating room anesthetizing locations (approved by House of Delegates 19 October1994). Park Ridge, Illinois. American Society of Anesthesiologists; 2001; last amended on 15 October 2003. http://www. asahq.org/publicationsAndServices/standards/14.pdf.2003. 88 Bhananker SM, Posner KL, Cheney FW, et al. Injury and liability associated with monitored anesthesia care: a closed claims analysis. Anesthesiology 2006; 104:228–234. 89 Lalwani K, Kitchin J, Lax P. Office-based dental rehabilitation in children with special healthcare needs using a pediatric sedation service model. J Oral Maxillofac Surg 2007; 65:427–433. Office-based dental rehabilitation using a pediatric sedation service model in disabled children is reasonably safe and obtains average savings of US$4849 per patient, compared with the hospital operating room. 90 Bogdonoff DL, Stone DJ. Emergency management of the airway outside the operating room. Can J Anaesth 1992; 39:1069–1089. 91 Arbous MS, Meursing AEE, van Kleef JW, et al. Impact of anesthesia management characteristics on severe morbidity and mortality. Anesthesiology 2005; 102:257–268.

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