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Ambulatory Anesthesiology: Review Article

Office-Based Anesthesia

Safety and Outcomes

Shapiro, Fred E. DO*; Punwani, Nathan MD; Rosenberg, Noah M. MD; Valedon, Arnaldo MD§; Twersky, Rebecca MD, MPH; Urman, Richard D. MD, MBA

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doi: 10.1213/ANE.0000000000000313
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The explosion in the volume and complexity of office-based medical and surgical procedures has fundamentally altered health care delivery. From 1995 to 2005, the number of office-based procedures has doubled to 10 million procedures per year.1,2 The growth in caseload is a profound change in how care is delivered; procedures, such as liposuction, abdominoplasty, and gastrointestinal endoscopy, which were once part of the hospital domain, have migrated to the office setting. Since the 1980s, the proportion of all outpatient surgeries performed in hospitals has steadily decreased from 90% to 45%, whereas the share performed in ambulatory surgery centers (ASCs) and physician offices has increased from <5% to 38 and 17%, respectively.3

This trend confers numerous advantages for medical providers and patients. Office-based procedures may offer more cost-effective solutions to surgical care than similar procedures in a hospital environment. Office surgery yields costs that are 60% to 75% lower than hospital-based settings.4 Nonhospital settings also offer patients a more intimate environment with its greater scheduling convenience, as well as perceived improvement in personal attention.


The shift in practice patterns away from hospitals to the office environment raises many issues of safety. For example, private offices may have fewer resources than other surgical care environments and often have less staff and equipment available when procedural and anesthetic complications arise.

As more procedures migrate to the outpatient sector, office-based procedures and anesthesia will be increasingly complex. Furthermore, the patient pool is getting ever more complicated as the population ages and develops more chronic medical conditions. The inherent capacity constraints at office-based practices suggest that such facilities may not have the necessary standby capacity to deal with difficult procedures and patients. The potential issue of safety and patient outcomes has received increased attention in many states, as well as professional societies. Adverse patient events, including deaths, and numerous high-profile incidents have caused states to impose moratoriums on office-based surgery (OBS) and office-based anesthesia (OBA).5

In response to these safety concerns, government regulations have evolved to highlight awareness of, and the need for, reporting of patient complications. Such regulations attempt to level the potential differences in care across surgical sites, but these efforts may not be commensurate with the rapid growth taking place in office procedures. Furthermore, the regulation of medical office suites is primarily done at a state and local level. Nearly 30 states have some degree of oversight over office-based practice, with many states still lacking office-specific regulation.6


There has been a lack of randomized controlled trials that have measured patient safety outcomes of morbidity and mortality in OBS and office-based medical procedures. On the contrary, there are numerous retrospective studies that compare morbidity and mortality outcomes in office, hospital, and ASC settings. As part of the methodology for this review, the MEDLINE/PubMed database was searched for papers using the terms “OBA,” “office surgery,” “ambulatory anesthesia,” “ambulatory surgery,” “patient safety,” “mortality and morbidity,” and “patient outcomes” both separately and in various combinations to maximize search results. The search was limited to studies in English regarding humans. The Cochrane database was also searched using the aforementioned terms, but we did not find any results. Included studies were published after the year 2000 and were all retrospective in nature.

Our search yielded studies that reported outcomes for relatively large groups of patients, generally on the order of thousands of patients. Qualitative heterogeneity in these studies limited further pooling of the data. Several smaller studies, on the order of hundreds of patients, were not included because of concerns about generalizability. For example, these smaller studies and case series were underpowered to detect serious adverse events such as major morbidity or mortality. Given concerns about generalizability, these studies would not have changed the analysis.

One of the earliest studies to raise doubts about the safety of OBA and procedures is by Vila et al.5 This retrospective study analyzed adverse events that were reported to the Florida Board of Medicine from 2000 to 2002. The case reports were collected from ASCs and physician offices. The authors deemed the relative risk of complications (including death) to be >10 times higher for office-based practices than for ASCs.

It should be noted that the findings of Vila et al.5 have not been corroborated by other studies. This is possible because the report by Vila et al.5 contains significant methodological limitations. Adverse events (the numerator in the analysis) were derived from both accredited and unaccredited offices. However, the total number of procedures (the denominator in the analysis) that were observed was compiled from only accredited sites. This would explain the artificially inflated relative risk of adverse events for office practices that other studies have not been able to replicate.

Numerous studies refute the conclusions of Vila et al.5 An earlier study by Fleisher et al.7 evaluated a sample population of Medicare patients (age >65 years) that had undergone more than half a million outpatient procedures from 1994 to 1999. The patient-oriented outcomes that were evaluated included rates of death and inpatient hospital admission within 7 days of receiving an outpatient surgery. The researchers calculated 1-week mortality rates in the office, ASC, and hospital as 0.035%, 0.025%, and 0.05% of outpatient procedures, respectively. The rate of admission to an inpatient hospital within 7 days of outpatient surgery was 9.08 per 1000 outpatient procedures at a physician’s office, 8.41 per 1000 outpatient procedures at an ASC, and 21 per 1000 outpatient procedures at an outpatient hospital (P < 0.05). The authors observed increased risk-adjusted rate of inpatient hospital admission or death within 7 days of surgery for procedures initially performed in the office compared to an outpatient hospital setting.

This study focused only on the elderly population, and it does not take into consideration a possible selection bias regarding which cases are scheduled for office versus hospital outpatient setting. However, the results suggest that office-based outpatient procedures may carry similar if not slightly higher risks of inpatient admission or death compared to other care settings.

Prior to Vila et al.,5 a study by Morello et al.8 scrutinized >400,000 cases at plastic surgery offices accredited by the American Association for Accreditation of Ambulatory Surgery Facilities (AAAASF). Surveys were sent to 418 accredited office sites and achieved a 57.7% response rate. The study tabulated 1 death for every 57,000 procedures. The rate of complications such as hematoma, wound infection, sepsis, hypertensive episode, and hypotension was 0.47%. The researchers concluded that the overall risk (defined as major complications, mortality, operating room returns, and hospitalizations) at AAAASF accredited offices is similar to free-standing or hospital-based outpatient surgery institutions. However, the main weakness of the study is potential selection bias since it relied on voluntary reporting and may not have captured the full profile of morbidity and mortality.

A study by Coldiron et al.9 was more direct in its criticism of the findings of Vila et al.5 Similar to Vila et al.,5 Coldiron et al.9 performed an incidence study of cases of death or hospital transfer for patients receiving office-based procedures as reported to the Florida Board of Medicine from 2000 to 2003. Coldiron et al.9 reported 13 procedure-related deaths and 43 procedure-related complications that required subsequent hospitalization. The researchers noted that 7 of the deaths were elective cosmetic procedure cases, 5 of which used general anesthesia. The authors found that OBS is not inherently unsafe compared to other settings, contradicting the conclusions of Vila et al.5 Instead, the authors focused on cosmetic surgery procedures that were associated with the reported complications and death, especially when performed under general anesthesia.

About 4 years later, Coldiron et al.10 published a follow-up study that examined 7 years of adverse events from medical offices as reported to the Florida Board of Medicine. From 2000 to 2007, the researchers observed 31 deaths and 143 procedure-related complications and hospital transfers. Liposuction, liposuction with abdominoplasty, or liposuction with other cosmetic procedure accounted for almost one-quarter of deaths in the study. Fifty-eight percent of the deaths and 61% of the complications were associated with some kind of cosmetic procedure. More than three-quarters of the deaths that occurred from office cosmetic procedures were American Society of Anesthesiologists (ASA) class 1 patients. The studies by Coldiron et al.10 suggest that safety concerns should be specifically directed at office cosmetic interventions rather than inappropriately generalizing all office-based procedures or certain anesthetic techniques as dangerous. Weaknesses of this study include its focus on one state’s population, which could cause cosmetic procedures to be overrepresented within the sample.

Keyes et al.11 analyzed >400,000 office procedures from 2001 to 2002. By using the AAAASF’s Internet-based data collection system, which office sites were required to participate in as a condition for receiving AAAASF accreditation, Keyes et al.11 were able to demonstrate the rate of complications of office-based interventions. For example, the total rate of complications such as hematoma, wound infection, sepsis, hypertensive episode, and hypotension was approximately 0.33%; 1 death occurred for every 58,810 office procedures. Although these findings were not risk-adjusted, they were similar to the mortality rate calculated by Morello et al.8 Thus, Keyes et al.11 determined that the injury and mortality risk of procedures performed by board-certified specialists at accredited office sites are on par with hospital surgical facilities.

Additional data from the AAAASF quality assurance program in accredited facilities included >1 million outpatient procedures from 2001 to 2006 and reported a mortality rate of 0.002%.12 One of 23 deaths was due to an intraoperative event, while 13 of 23 deaths were caused by pulmonary embolism. The authors point out that pulmonary embolism, the most likely cause of perioperative mortality, can occur after any operative procedure, whether it is performed in a hospital, an ASC, or a physician’s OBS facility. Thus, the causes of morbidity and mortality in office-based cases are similar to the risk profiles in other settings. The researchers also emphasized that the office procedure most linked to death from pulmonary embolism is abdominoplasty. Again, a common theme of many of the studies cited is that office-based procedures achieve similar patient outcomes as procedures performed in other settings. Furthermore, they highlight inherent risks in specific office cosmetic procedures, which would not be generalizable to all OBS. One caution about drawing conclusions from the results of this study is that although most of the reported cases may have been from OBS practices, the database does not distinguish between ASC-accredited facilities and OBS-accredited facilities.

There have also been a variety of studies assessing which anesthetic techniques are optimal for the office practice. Hoefflin et al.13 saw no cases of mortality after reviewing 23,000 general anesthesia office procedures; although based on the aforementioned mortality rates found by Keyes et al.12 and Morello et al.,8 the study may have been underpowered for detecting mortality. Perrott et al.14 evaluated the safety of office-based oral and maxillofacial procedures; the researchers calculated a complication rate that ranged from 0.4% to 1.5% for local anesthesia, conscious sedation, and general anesthesia. Complication types included gastrointestinal (i.e., vomiting at the time of induction or in the recovery area, 0.1% and 0.3%, respectively), laryngospasm, bronchospasm, or other associated respiratory complications (0.3%), cardiac arrhythmia (0.1%), syncope (0.1%), seizure (<0.1%), neurologic impairment (<0.1%), prolonged recovery (0.2%), peripheral vascular injuries or complications (0.2%), and other complications (0.1%). As a result, the authors declared that all 3 kinds of anesthetics could be used safely in office settings. Bitar et al.15 examined 4778 plastic surgery cases performed under monitored anesthesia care (MAC)/IV sedation. There were no deaths, ventilator requirements, or deep venous thromboses, and complications included short-term dyspnea with 1 case requiring emergent intubation, postoperative nausea and vomiting (PONV), and inpatient admission. Based on these results, the authors concluded that OBS under MAC/IV sedation is safe when performed by board-certified plastic surgeons and nurse anesthetists. On the contrary, Coldiron et al.9 concluded that there was an increased mortality risk in patients undergoing tumescent liposuction under general anesthesia. The authors believed that office liposuction could be safer if plastic surgeons eschewed general anesthesia in favor of dilute local anesthesia.


Accreditation is a critical issue that will indelibly affect the field of OBS and office-based medical procedures. One of the arguments for accreditation of office-based facilities is to ensure that practitioners have a process for credentialing and privileging, similar to the processes usually in place at ASC and hospital-based facilities. This would create a more transparent process for assessing provider’s qualifications and whether the provider is practicing outside of his or her usual scope of practice. Office-based organizations would be encouraged to develop a process for assessing the education and training needed to grant specific privileges. Moreover, there is also variation in who administers sedative drugs at OBS facilities. At some sites, nonanesthesia personnel provide and manage sedative drugs to patients, while other places make this the exclusive responsibility of anesthesia-trained professionals. The divergence in credentialing requirements between hospital and ambulatory facilities may create uncertainty in the quality of care at office-based settings.

To fill the vacuum left by differing credentialing standards, states are increasingly either recognizing or mandating accreditation of office facilities. Currently, nearly 30 states have some degree of regulation of OBS, and some, such as Florida and New York, actually require accreditation by one of the nationally recognized accrediting organizations. Although there is significant state-by-state variability in these requirements, it is likely that other states will follow suit.6

Unfortunately, there is a dearth of research evaluating claims that board-certified physicians with hospital privileges to perform the same type of procedure they perform in the office improve outcomes or that nonaccredited offices deliver substandard medical care. Although the preponderance of research shows that medical offices can deliver safe care, Clayman et al.16 emphasize that medical offices should strive to meet certain structural quality standards. Coldiron et al.9 analyzed office surgical incidents from 2000 to 2003 and concluded that mandating board certification and hospital privileges to perform office procedures would have marginal impact on the safety of office procedures. In their study population, 96% of physicians involved in office surgical incidents were board-certified, and all of them had hospital privileges.

Koch et al.17 presented the first longitudinal review of OBA in 2003, examining, among other things, its safety based on the small number of large-scale case reports in existence at that time. For example, according to Koch et al.,17 a Los Angeles plastic surgeon reported no fatalities or cardiopulmonary emergencies during a 10-year span from 1962 to 1972, over which time he completed >5000 procedures. In addition, in a smaller study comparing 896 office-based versus 634 hospital-based intraocular procedures performed from 1983 to 1986, no systemic complications were reported in the office-based group. Other studies were included in this review but are discussed in more detail below. Without drawing a conclusion from the small number of studies available at the time and without possessing accurate data on risk adjustment or the types or qualifications of the practitioners, Koch et al.17 explicitly raised the question: are patients actually at any higher risk when an anesthesiologist cares for them in the office-based venue versus the ASC or hospital-based environment?

Coldiron et al.10 performed another study investigating 7 years of adverse office surgical outcomes in Florida. From 2000 to 2007, there were 143 procedure-related complications and hospital transfers, as well as 31 deaths. Approximately half of the deaths and hospital transfers were from plastic surgery procedures; most (92.5%) of these physicians were board-certified and had hospital privileges (96.6%). Nearly 60% of deaths and complications were from cosmetic procedures. Of these fatalities, a staggering 78% were in ASA class 1 patients. Almost 40% of deaths and hospital transfers were from accredited sites.

Similarly, a study by Starling et al.18 examined 6 years of mandatory adverse event reporting in the state of Alabama. The researchers found that medical offices were involved in 3 deaths and 49 procedure-related complications and hospital transfers. All these adverse events occurred in the offices of board-certified physicians. Furthermore, 71% of offices reporting an adverse event were accredited by an independent agency. Consequently, the research of Coldiron et al.10 and Starling et al.18 demonstrates the potential limits of accreditation, physician board certification, and hospital privileges in meaningfully reducing office procedural complications. Table 1 summarizes key studies and outcomes reported over the last 10 years.

Table 1:
Recent Studies on the Safety of Office-Based Anesthesia and Procedures

However, it should be noted that the work of Coldiron et al.10 and Starling et al.18 is raw population studies that are unadjusted for the health risk of the patients at the various office sites. The researchers also aggregated their data from all the medical and surgical specialties. In addition, their studies may not be applicable to other states because Florida’s definition of an adverse outcome could vary from other states. For example, Florida requires medical offices to report an adverse event if any complications arise up to 9 days after an office procedure took place. Other states may not share the same mandatory adverse event reporting standards, and Table 2 illustrates variation in adverse event reporting requirements in 5 sample states. Lastly, since Coldiron et al.10 only analyzed reportable adverse events from medical offices, they were unable to estimate the total volume of office procedures that occurred each year. This made it difficult to ascertain the overall rate of complication. A spike in the number of complications from a given year could be due to an underlying increase in the volume of office procedures and not because of a higher complication rate. Consequently, it may not be prudent to use the studies of Coldiron et al.10 to draw sweeping conclusions regarding the impact of accreditation on the morbidity and mortality profile of office surgery.

Table 2:
Examples of Office-Based Surgery Outcomes Reporting Requirements by State

Hancox et al.20 performed a literature review to assess whether there was a relationship between board certification and adverse events from OBS. The authors were unable to arrive at any firm conclusions because there was a lack of uniformity in the reporting of adverse outcomes. In the meantime, the researchers advised, based on very limited data, that office procedures “should only be performed by properly trained physicians working within their scope of practice.” With respect to anesthesia practice, Hancox et al.20 declared that “certified anesthetists or anesthesiologists should administer anesthesia and carefully monitor patients” in select circumstances.


It is imperative for anesthesiology providers to select appropriate patients for OBA. Medical offices should formulate internal practice standards for defining suitable patients for OBA. The ASA endorsed general criteria for patient selection, and these standards should be the same regardless of the location of ambulatory care.21 The criteria include an assessment of the patient for the following: medical history, family history, current medications, drug or latex allergy, deep vein thrombosis and pulmonary embolus risk, and social and psychological history. As for any ambulatory setting, anesthesia providers must be vigilant regarding the presence of high-risk medical conditions. Examples include morbid obesity, obstructive sleep apnea or severe chronic obstructive pulmonary disease, end-stage renal or liver disease or abnormalities of other major organ systems, myocardial infarction within the last 6 months, uncontrolled hypertension, acute substance intoxication, poorly controlled diabetes mellitus, sickle-cell disease, stroke within the last 3 months, poorly controlled psychiatric problems, acute intoxication, or a known difficult airway.22–25 To identify patients with high-risk medical conditions, the office should use screening questionnaires completed by the patient and facility sharing of the information and open communication between surgeons and anesthesia providers. Anesthesia providers must also inquire whether the patient has experienced previous adverse events from anesthesia and surgery. A family history should be performed to assess the presence of malignant hyperthermia. When collecting a social and psychological history, anesthesia providers should note if the patient has a record of alcohol, analgesic, or sedative abuse and should also assess if a responsible adult will accompany the patient during the perioperative period or escort the patient back home. All appropriate preoperative testing should be completed before the day of the procedure.24 By adopting standards for patient selection in all ambulatory settings, anesthesia providers may be able to minimize the morbidity and mortality of office-based interventions.21


OBA providers have to evaluate the nature of the procedure and its appropriateness for the ambulatory setting, also taking into consideration anticipated procedure duration and complexity. In making such a determination, they should gauge, for example, how much blood loss may be incurred during the procedure or the amount of postoperative pain. Thus, intrathoracic, intracranial, and major intraabdominal and vascular procedures may not be appropriate for the office-based setting.1,26 The goal is to ensure that the patient can recover and be discharged within a reasonable time. Anesthesia providers should examine the resources of the office practice and the extent of resources available (both in personnel and equipment) to deal with possible surgical complications. Specifically, anesthesia professionals must conclude whether the location and its resources are capable of supporting the provision of anesthetics and whether it can deliver the proper intensity and duration of postoperative monitoring.21

Phillips et al.27 addressed the topic of procedure selection indirectly in their study of anesthesia duration as a marker for surgical complications in office-based plastic surgery. In a retrospective review of 2595 patients who underwent office-based plastic surgery from 2000 to 2005, they examined minor and major complication rates as a function of anesthesia duration less than or more than 4 hours. They found a statistically significant increase in minor complications, including nausea and vomiting and urinary retention in the >4-hour group. They concluded that duration of general anesthesia does not seem to be an indicator of major morbidity and morality because there was no statistically significant difference in the rates of reoperation or other major complications between the 2 groups. Based on 1200 patients undergoing facial plastic surgery lasting >4 hours, a study by Gordon and Koch28 found no correlation between duration of surgery or anesthesia and patient morbidity and mortality.

There are specific procedures that demand singular consideration if they are to be performed in the office setting. On balance, these potentially high-risk interventions tend to be cosmetic or dental procedures, although similar risks can be applicable to other types of procedures. Cosmetic procedures, especially liposuction, are deemed by safety literature to be higher-risk office procedures and thus warrant particular discretion. As evidenced by Keyes et al.,12 patients undergoing office cosmetic procedures, especially abdominoplasty, are at increased risk of deep vein thrombosis and complications like death from pulmonary embolism. Consequently, the American Society of Plastic Surgeons advises office practices to institute a policy of thromboembolism prophylaxis in patients, which is also a nationally recognized quality measure and one of the important Surgical Care Improvement Project measures.29

There are specific caveats for office liposuction per recommendations from the American Society of Plastic Surgeons. It is recommended that liposuction procedures that are combined with another procedure, such as abdominoplasty, should not be performed in surgical office suites, especially if the total surgical time is expected to exceed 6 hours.29,30 Large volume liposuction (procedures that involve >5 L of total aspirate or >2 L if the liposuction is an adjunct procedure) should also be eschewed from the office setting.30

Certain forms of liposuction, including tumescent and superwet techniques, can be performed by office-based plastic surgeons, but such interventions create additional demands and constraints for office surgical providers. For example, tumescent and superwet liposuction techniques require areas of surgery to be injected with large volumes of dilute, local anesthetic solution such as combined crystalloid and lidocaine with epinephrine.30 During such procedures, it is advised that the epinephrine in the solution does not surpass 0.07 mg/kg. Copious injectate volumes could cause patients to experience hypervolemia. As a result, providers who perform office liposuction should devise plans for appropriate fluid management depending on the individual needs of the patient. Patients are also at risk for hypothermia since the injectate fluids are typically not warmed. Therefore, office plastic surgery suites should consider acquiring active warming devices to avert hypothermic complications from fluid administration. By being cognizant of the particular requirements that cosmetic procedures entail, office-based proceduralists can tailor their practices to deliver safe care for such patients.

Similarly, office-based dental interventions are another field in which discretion must be exercised in procedure selection. Depending on the state, dentists providing sedation or anesthesia services may need additional licensing from the state dental board to render anesthesia services.1 Anesthesia providers should be aware of the spatial and capacity constraints of dental rooms, which are usually smaller than a surgical operating room. This could impose limitations on patient positioning, impeding an anesthesiologist’s ability to engage in airway management. In addition, the anesthesiologist and the dentist are simultaneously “working” in the patient’s airway; this could complicate efforts in managing changes in ventilation and clearing foreign bodies, blood, and other secretions created from dental drilling.21

Features that are omnipresent in hospital operating rooms, such as backup power, scavenging, and dedicated suction, may not be available in dental suites.1 Thus, the onus is on the anesthesia provider to ensure that office practice conditions do not generate additional risks for patients, and if necessary, provide their own equipment for temporary setup. In terms of anesthesia requirements, providers should be mindful that dental procedures often involve brief episodes of surgical stimulation. Consequently, anesthesia caregivers should be prepared to provide short-acting supplemental sedation during those situations. Anesthesia providers should consider all these factors when taking part in procedure selection for the dental office.


There are no randomized studies assessing the safety of OBA. Much of the available literature confirms that the low rate of complications during office-based procedures and OBA is similar to that in other ambulatory settings, as evidenced by similar morbidity and mortality profiles across different practice environments.7,9,12,13 The choice of an anesthetic drug and technique should be tailored to the patient’s health condition, planned procedure, and available equipment. As with any ambulatory setting, the goal is rapid recovery from anesthesia, minimal side effects, and rapid discharge. Local, minimal to deep sedation, general and regional anesthetic techniques have been successfully used in the office-based practice, with minimal to deep sedation (with or without local anesthesia) being the most common technique.13,31–35 However, with the growing complexity and duration of office-based procedures, there is an increasing demand for general anesthesia to protect the airway, provide a stable level of anesthesia and improve operating conditions for the surgeon.28 A wide range of medications have been used, ranging from short- and long-acting opioids (e.g., remifentanil, fentanyl, hydromorphone), benzodiazepines (e.g., midazolam), ketamine, and propofol, used either alone or in combination.36,37 There is increased emphasis on premedication with long-acting antiemetics (e.g., aprepitant, palonosetron, transdermal scopolamine), nonsteroidal anti-inflammatory drugs (e.g., IV ibuprofen, ketorolac), and IV or oral acetaminophen to speed up recovery and improve patient satisfaction after ambulatory surgery.38 Two additional adjunct drugs that have been successfully used are dexmedetomidine and clonidine, showing beneficial effects in plastic surgery procedures.21 Inhaled drugs such as desflurane and sevoflurane have also been used. In one study, the use of desflurane resulted in improved intraoperative conditions during OBS compared to propofol.39 The authors also reported that the use of desflurane with routine antiemetic prophylaxis was associated with a faster recovery and comparable postoperative side effects. Nitrous oxide, either alone or in combination with IV or other inhaled anesthetics, remains a popular choice as a way to decrease anesthetic requirements, costs, and expedite emergence from anesthesia, although its effect on PONV remains a subject of debate.37,40 Total IV anesthesia usually administered with propofol alone or in combination with an opioid can have advantages over inhaled anesthesia if there is lack of capacity to deliver or scavange inhaled drugs, desire to avoid malignant hyperthermia-triggering drugs, and decrease the risk of PONV.41,42 As with any other ambulatory setting, opioid-sparing anesthetic techniques and the use of local anesthetics and nonopioid analgesics can help reduce PONV and expedite patient recovery and discharge.41 Multimodal approaches to anesthesia and pain management usually include drug combination techniques that maximize the use of long-acting local anesthetics and anesthetics that help minimize PONV and pain, while allowing rapid emergence from anesthesia and discharge from the recovery room. Postoperative fast-tracking helps improve process efficiency, maximize resources, and increase patient satisfaction. Successful fast-tracking depends not only on anesthesia techniques but also on specific patient and procedure factors.43

With a reported incidence of PONV in outpatients ranging from 20% to 30% and postdischarge nausea and vomiting from 30% to 50%,44 a multimodal approach to both prophylaxis and treatment should be considered, including the use of long-acting antiemetics. In fact, Apfel et al.44 reported that patients who experienced nausea in the recovery room had a 3-fold increased risk of postdischarge nausea and vomiting. Postoperative anesthesia care should comply with existing standards set forth by the American Society of Anesthesiologists and other national organizations. The anesthesiologist should provide the overall direction of the postanesthesia care unit, and the same standard of care should be emphasized regardless of the type of ambulatory setting. This includes adequate and properly trained postanesthesia care unit staff, availability of emergency equipment, robust discharge criteria, and patient follow-up.45,46


Most of the knowledge regarding OBA patient safety stems from the American Society of Anesthesiologists’ Closed Claims database. The medical liability database collects information about the nature and number of claims associated with adverse anesthesia events. Because there is a 3- to 5-year interval between event occurrence and entry into the database, the impact of guidelines and accreditation may not yet be reflected in the trend of OBA Closed Claims. In the first report of OBA Closed Claims, Domino47 reported that the severity of injury for office-based claims was worse than for other ambulatory anesthesia claims. Forty percent of office-based claims were for death, whereas 25% were for other ambulatory anesthesia claims. As a result, office-based liability payouts were more likely to result in payment, and the median payouts tended to be larger than adverse anesthesia outcomes in other ambulatory settings. Respiratory events, airway obstruction, bronchospasm, inadequate oxygenation-ventilation, and esophageal intubation were the most common complications (29%). These adverse events were deemed preventable by better monitoring, particularly during the postoperative period. Since that publication, additional data have been submitted and there appears to be a decrease in claims for medication errors, but a nearly 3-fold increase in claims related to equipment malfunction (17%).48

Although the American Society of Anesthesiologists’ Closed Claims database does not include true denominator data since it only contains the reports but not the total number of incidents where no lawsuits were filed, it exposes how vulnerable office anesthesia is to quality lapses. Areas for improvement include oversedation during MAC, failure to recognize and promptly manage respiratory depression, prevention of cautery burns, hazards of anesthesia in nonoperating room locations,47 and management of the difficult airway, especially during tracheal extubation.

Because many OBA are administered as MAC, the injury and liability profile of MAC, as reported by the American Society of Anesthesiologists’ Closed Claims database, warrants careful scrutiny. Bhananker et al.19 showed that 21% of MAC liability incidents were caused by respiratory depression, making it the most frequent mechanism of injury. Respiratory depression in MAC was a common complication due to the administration of sedative drugs. Diminished breathing associated with hypoxia can cause brain damage and death. The researchers established that death or permanent brain damage accounted for 40% of MAC claims. This proportion is similar to what is observed in general anesthesia claims and implies that MAC and general anesthesia have comparable risk profiles. Bhananker et al.19 concluded that nearly half of liability episodes could have been prevented with audible alarms, improved monitoring such as capnography, and increased overall vigilance. Based on this study, it is difficult to derive any conclusions about the safety of MAC versus general anesthesia in the office-based setting, since cases from both inpatient and outpatient facilities were included. Bhananker et al.19 also revealed that facial plastic surgery was 26% of MAC liability incidents. Moreover, operating room fires occurring on patients’ faces were implicated in 17% of all claims. This type of injury is a high risk in facial plastic surgery. These dangerous events are considered to be preventable because they are the direct consequence of a “fire triad” of ignition consisting of electrocautery, combustible substances (alcohol prep, paper drapes, plastic masks), and supplemental oxygen.49 This fact also underscores the high-risk nature of certain procedures performed in the office setting.

The effect of anesthesia type on complication rate may be counterintuitive. For example, the Swiss anesthesiology closed claims analysis examined claims filed between 1987 and the end of 2009. One hundred seventy-one events leading to anesthesia-related injuries were entered into the database. The majority (54%) were related to regional anesthesia, while general anesthesia accounted for 28%, and other anesthesia-related procedures for 18%.50 The quality of care was judged to be substandard in the majority of cases (55%), resulting in death in 12% and permanent injury in 63% of patients. It is possible that either regional anesthesia confers greater complication risk resulting in permanent injury or patients having higher-risk procedures are more likely to undergo regional versus general anesthesia. The authors concluded that an unusually high incidence of complications related to regional anesthesia may be related to the peculiarities of the Swiss medical and legal systems and anesthesia care. In addition, if equally effective anesthetic alternatives are available, a patient should not be persuaded to accept an anesthetic procedure other than his or her preferred choice.

Most of the evidence-based literature in patient safety related to OBS comes from the plastic surgery field. Unfortunately, this literature focuses on surgical outcomes with limited mention of anesthesia-related complications, such as nausea and vomiting, pain, delayed discharge, or patient satisfaction. Therefore, large-scale data collection and reporting were difficult to accomplish until recently. Recent data compiled from the Society for Ambulatory Anesthesia Committee on OBA reported outcomes and complications in a database of 37,669 OBA cases collected from 7 practices between 2008 and 2010.a More than 60% of the cases were gastrointestinal and dental procedures. It appears that overall complication rates were very low. Case cancellation was the most frequent event (3.2%), possibly reflecting a more conservative approach in OBA or inadequate preparation of the patient without the resources and protocols of an ASC or hospital. Unplanned admission rates were 0.07%, and the rates for minor complications were all <1%. No deaths were reported. The data collected from the aforementioned anesthesia sites showed that OBA compared favorably with safety and outcome data from ambulatory, hospital-based practices.a It is difficult to draw any definitive conclusions from the aforementioned study, given the small number of self-selected participants who voluntarily reported their outcomes data. As participation in anesthesia outcomes registries, including the Society for Ambulatory Anesthesia Clinical Outcomes Registry ( and the American Society of Anesthesiologists’ Anesthesia Quality Institute Data Registry ( continues to increase, there will be an opportunity to develop comparative benchmarks for anesthesia outcomes. Recently, an OBA-specific checklist template was developed, based on the World Health Organization checklist, as a means to further improve safety.51


Regulations and oversight for outpatient surgical care in hospitals and ASCs will very likely continue to shape the future directions that office procedural practice could take. State entities are shifting their focus onto office facilities and requiring them to be appropriately credentialed, if not restricting the types of procedures performed in such settings. For example, New Jersey is contemplating legislation that would ban liposuction and breast prosthesis procedures from being performed at any unaccredited office site.52 Florida is requiring facilities that perform liposuction to document removal of supernatant fat; facilities that remove >1000 mL of supernatant fat would need to be accredited by the Accreditation Association of Ambulatory Health Care.53

Many states and some private payers are enacting regulations and guidelines for office-based procedures. It is also reasonable to assume that the federal government will take a more active interest in the office sector and adopt federal regulations that would affect providers who receive payments from governmental programs such as Medicare and Medicaid. In June 2012, the Government Accountability Office published a report calling attention to the extent of blood-borne pathogens and other negative public health ramifications that stem from poorly regulated office facilities.54 Early in 2012, the Centers for Medicare & Medicaid Services initiated a quality reporting program whereby ASCs are required to report on 5 quality measures: patient burns, patient falls, timing of prophylactic antibiotic provision, wrong patient/side/procedure or implant, and hospital transfers. Two additional measures were added for 2013: use of a safe surgery checklist and volume of certain surgical procedures. Coverage of influenza vaccination for health care workers will be added in the future. Not reporting such quality measures to Centers for Medicare & Medicaid Services will result in payment penalties in the future.55 Such regulations could, and may, eventually be extended to the office setting. State and federal laws and regulations are directing hospitals and ASCs to take part in mandatory data collection and quality reporting, such as the reporting of certain Surgical Care Improvement Project measures. Although many of the aforementioned metrics are hospital-based, office-based care would be driven by provider-based metrics, at least in the near future. It is plausible, however, that offices performing invasive procedures will inevitably participate in similar but mandatory quality improvement efforts.

Lastly, the burgeoning number and intricacy of office procedures, as well as the complexity of patients undergoing those procedures, mean that the office setting will inexorably encompass a widening array of medical and surgical specialties. In addition to financial incentives, further development of minimally invasive technologies and advanced techniques will drive more procedures into the office-based setting, including an increasing number of gynecologic, orthopedic, pain and ophthalmologic, interventional radiologic, and vascular procedures. One can logically predict that a framework for interspeciality collaboration will have to be developed so as to achieve consensus on evidence-based guidelines for clinical standards of office-based procedures. Third party payors and the public will increasingly exert pressure on clinical professional societies to cooperate as part of an effort to continuously improve patient-oriented measures of morbidity and mortality in the office procedural setting.


The growth of OBA is a consequence of economic and social factors, as well as the evolution of improved surgical techniques and anesthetic drugs suitable for the ambulatory environment. Despite these advances, there is still a limited amount of primary literature that examines safety and quality in the office-based setting. More recent retrospectively collected data generally point to a similar risk profile in the office compared to other practice locations, and one can speculate that proper provider credentialing, qualifications, and facility accreditation can further improve patient outcomes. Improvements in care can be made with nationwide standardization of care, safety checklists, and development and adherence to professional practice guidelines. Furthermore, evidence from existing literature points to the safety of general anesthesia, although special emphasis should be placed on proper training of the providers and ensuring availability of necessary equipment and contingency plans. More high-quality clinical studies on safety and outcome are needed. As more studies emerge from prospectively collected data using large administrative databases, we will be able to make more definitive conclusions about patient safety and outcomes.


Name: Fred E. Shapiro, DO.

Contribution: This author reviewed the paper design and literature, analyzed the data, and prepared the manuscript.

Attestation: Fred E. Shapiro approved the final manuscript.

Name: Nathan Punwani, MD.

Contribution: This author reviewed the paper design and literature, analyzed the data, and prepared the manuscript.

Attestation: Nathan Punwani approved the final manuscript.

Name: Noah M. Rosenberg, MD.

Contribution: This author reviewed the paper design and literature, analyzed the data, and prepared the manuscript.

Attestation: Noah M. Rosenberg approved the final manuscript.

Name: Arnaldo Valedon, MD.

Contribution: This author reviewed the paper design and literature, analyzed the data, and prepared the manuscript.

Attestation: Arnaldo Valedon approved the final manuscript.

Name: Rebecca Twersky, MD, MPH.

Contribution: This author reviewed the paper design and literature, analyzed the data, and prepared the manuscript.

Attestation: Rebecca Twersky approved the final manuscript.

Name: Richard D. Urman, MD, MBA.

Contribution: This author reviewed the paper design and literature, analyzed the data, and prepared the manuscript.

Attestation: Richard D. Urman approved the final manuscript.

This manuscript was handled by: Peter S. A. Glass, MB, ChB.


a Walsh MT, Kurrek MM, Desai M. Anesthesia outcomes in office-based anesthesia. Proceedings of the annual meeting of the American Society of Anesthesiologists, 2010; A798.
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