Office-based anesthesia

INTRODUCTION — In the United States, the proportion of all outpatient surgical procedures performed outside a hospital setting has increased from <10 percent in 1979 to approximately 60 percent, with 15 to 20 percent performed in office-based settings [1]. Outpatient procedures increased from 129 million cases in 2018 to approximately 144 million cases in 2023 [2]. In part, this shift is due to newer surgical and anesthetic techniques that have allowed more invasive procedures to be safely performed in nonhospital settings.

As part of this trend, the number of elective surgical procedures performed in an office-based setting has expanded rapidly [1,2]. Also, more medically complex patients are now receiving anesthetic care in these settings [3]. This topic will review potential advantages and concerns, patient and procedure selection, and anesthetic and postoperative management specifically for patients undergoing procedures in office-based settings.

A separate topic addresses management of patients in other nonoperating room anesthetizing locations. (See "Considerations for non-operating room anesthesia (NORA)".)

POTENTIAL ADVANTAGES AND BENEFITS

●Advantages – Potential advantages of performing procedures in an office-based setting include [1,4,5]:

•Patient-specific advantages – Patient convenience with perception of greater personal attention and privacy.

•Surgeon-specific advantages – Surgeon convenience with perception of greater ease of scheduling, consistency in nursing personnel, and efficiency.

•Institutional advantages – Cost containment compared with hospital settings. However, patient selection is important to avoid losing this advantage (eg, patients who are more likely to require urgent or emergency care in the postoperative period or hospital readmission). (See 'Patient selection' below.)

●Benefits – Potential benefits when procedures are performed in an office-based setting include [4,6,7]:

•Possibly lower nosocomial infection rates

•Decreased thromboembolic complications

•Quicker postoperative mobilization, which may reduce complications

•Earlier physical therapy and rehabilitation

•Greater patient satisfaction

SAFETY CONCERNS — Office-based surgery (OBS) has emerged as a significant subspecialty of ambulatory surgery. Differences between OBS and ambulatory surgery center (ASC) settings include demographics, procedure types, and reported adverse events [2,8].

Safety concerns have centered around the adequacy of individual facility resources and governmental regulations for office-based facilities.

Adequacy of facility resources — Appropriate resources (eg, personnel, equipment, medications, space) for performance of specific surgical procedures are necessary in an office-based facility, particularly as more invasive and time-consuming interventions are being offered in such settings [1,9].

Access to adequate resources may be critically important when procedural or anesthetic complications occur [10]. Office-based facilities should have personnel, equipment, and drugs to initiate treatment of any crisis situation including unanticipated difficult airway, anaphylaxis, local anesthetic systemic toxicity, malignant hyperthermia [MH]), or major cardiovascular events including cardiac arrest. The facility should stock difficult airway tools (videolaryngoscopes), defibrillators, emergency drugs for advanced cardiac life support (ACLS), and 20% lipid emulsion to treat systemic toxicity of local anesthetics. Furthermore, drugs for MH crisis should be immediately available (eg, either dantrolene or its newer preparation Ryanodex, which is easily reconstituted with 5 mL sterile water and administered in less than one minute by a single health care practitioner) if any triggering agent such as succinylcholine (SCh) or volatile inhalation anesthetics are stocked at the facility (table 1). Cognitive aids for management of these crises should also be immediately available [11], as discussed in detail in a separate topic. (See "Cognitive aids for perioperative emergencies".)

Responsibilities for anesthesiologists planning to practice in office-based settings include preanesthetic inspection of all anesthesia and emergency equipment (table 1) (see 'Professional society guidelines' below and 'Anesthetic management' below). Also, examination of the entire anesthesia work area is performed to ensure that space requirements are met. Discussions with the perioperative team are important to ensure that established policies and procedures regarding fire, safety, drugs, emergencies, staffing, training, and unanticipated patient transfers are in place and up to date, and that compliance with all applicable federal and state laws, codes, and regulations has been achieved (table 2) [1]. (See 'Government regulations' below.)

Government regulations — Office-based facilities are typically subject to a lesser level of state and federal regulations compared with hospitals and other ambulatory surgery facilities [1,10,12]. Accreditation of office-based facilities allows a third party to monitor activities and provide external benchmarking, validation, and acknowledgment of a nationally recommended standard of care. However, state laws vary, and many lack regulations specific for office-based settings [1,9,10].

Since the types of procedures and patient populations eligible for an office-based setting are increasing in number and complexity, additional regulations have been implemented by accreditation and state regulatory agencies, although uniformity and evidence-based standards of care are lacking [10]. For example, the New York Department of Health has mandated that OBS practices must provide continuous monitoring of end-tidal carbon dioxide using capnography during moderate or deep sedation, as well as during general anesthesia, consistent with the 2018 American Society of Anesthesiologists (ASA) practice guidelines for moderate procedural sedation and analgesia [13,14]. However, not all states have this mandate.

Other differences in state regulations exist. For example, although patients may develop MH after exposure to a triggering anesthetic agent (see "Malignant hyperthermia: Diagnosis and management of acute crisis"), guidelines presented in 2017 by the Society for Ambulatory Anesthesia (SAMBA) recognize that this is unlikely in office-based facilities that perform procedures exclusively with oral or intravenous sedatives/analgesics ("class B" facility) [15]. Such facilities typically do not stock dantrolene, the antidote for MH, because no known triggers (eg, volatile inhalation anesthetic agents) are used in the facility. Since SCh is considered a trigger for MH, many such facilities do not stock SCh. However, SAMBA's position statement notes that the risk of losing a patient's airway and needing appropriate drugs such as SCh to manage this emergency exceeds the risk of an MH event [15]. Thus, some accreditation and state regulatory agencies now allow facilities to stock SCh to manage emergency airway rescue without requiring they also stock dantrolene to manage MH.

Professional society guidelines — We use guidelines for office-based anesthesia adopted by the ASA, which emphasize that standards for anesthetic care in an office should be the same as those in hospitals or ambulatory surgery centers (ASCs) [16]. These guidelines address patient selection, monitoring, perioperative care, and facility management (Guidelines for Office-Based Anesthesia), as well as qualifications of anesthesia providers, training, and credentialing in this setting (Statement on Qualifications of Anesthesia Providers in the Office Based Setting), and distinguishing monitored anesthesia care (MAC) from moderate sedation/analgesia (ie, conscious sedation) [14,17]. Guidelines also address the need for qualified personnel being present for the entirety of the procedure until the patient has been discharged from anesthesia care, documentation of the discharge decision by a responsible clinician, and immediate availability of personnel with training in ACLS and/or pediatric advanced life support (PALS) [1,16]. Ongoing training of office-based personnel is emphasized so that rare emergencies will not overwhelm staff capabilities until the patient can be transferred to another facility. Furthermore, an immediate communication line to a more advanced facility is necessary to relay pertinent information in the event of an emergency transfer [1].

Similar professional society guidelines emphasizing core patient safety principles for OBS procedures have been endorsed by the American College of Surgeons (ACS) [18], the World Federation of Societies of Anaesthesiologists (WFSA) [19], and some state medical societies [20].

Use of checklists

Routine checklists and briefings — Use of checklists with an incorporated briefing such as the World Health Organization (WHO) surgical safety checklist helps ensure that safety measures are followed (table 3). Other organizations have developed other checklists (eg, the Association of periOperative Registered Nurses [AORN], the American Gastroenterological Association [AGA], the American College of Gastroenterology, and the American College of Surgeons) [21]. The Institute for Safety in Office-Based Surgery (ISOBS) has developed a checklist that is based on the WHO surgical safety checklist but is specifically adapted to the needs of an office-based setting (form 1) [22,23]. Checklists that actively involve the patient may increase satisfaction, decrease medical liability claims, and improve thoroughness of medical care by empowering the patient to participate in his or her own health care [24,25]. (See "Patient safety in the operating room", section on 'Timeouts, briefing, and debriefing'.)

A single-center study in a plastic surgery office-based setting demonstrated a reduced complication rate from 15.1 to 2.72 per 100 patients after implementation of a safety checklist [26]. However, in one survey, only 50 percent of OBS practices reported using a safety checklist [27]. Those not using checklists cited several obstacles to their implementation (eg, no incentive to use a checklist, no mandate from a local or federal regulatory agency, too time-consuming, lack of training).

Crisis checklists — Crisis checklists (also termed cognitive aids or emergency manuals) have been developed to manage relatively rare crisis situations that may occur during any surgical and other interventional procedures. These could be lifesaving during an emergency in an office-based setting by ensuring that best practices are followed and no critical steps are missed [25]. A set of such aids should be immediately available. An example is the 2018 ISOBS emergency manual customized to be specific for office-based settings (available at the Emergency Manuals Implementation Collaborative website), which is designed to deal with the most commonly encountered emergencies [11,28]. (See "Cognitive aids for perioperative emergencies".)

Details regarding management of specific crisis situations can be found in separate topics:

●(See "Management of the difficult airway for general anesthesia in adults".)

●(See "Perioperative anaphylaxis: Clinical manifestations, etiology, and management".)

●(See "Local anesthetic systemic toxicity".)

●(See "Malignant hyperthermia: Diagnosis and management of acute crisis".)

●(See "Advanced cardiac life support (ACLS) in adults".)

●(See "Fire safety in the operating room", section on 'Management of a fire'.)

Outcomes — The number of outpatient procedures in the United States increased from 129 million cases in 2018 to approximately 144 million cases in 2023 [2]. Furthermore, patients in outpatient settings have more complex medical comorbidities and are undergoing more complicated procedures [3]. Limited published data exist describing patient characteristics, anesthesia, or outcomes that distinguish OBS from ASC settings. One 2022 retrospective observational study included nearly 90,000 cases performed from 2016 to 2019 by a large group of mobile anesthesia practitioners [2]. Over this time period, the number and complexity of procedures increased substantially in both OBS and ASC settings. Compared with ASCs, OBS patients were older (61 versus 55 years of age) and had a higher American Society of Anesthesiologists (ASA) physical status classification (table 4) (33 versus 20 percent were ASA 3 or higher). The leading procedures in ASC settings were cataract removal and orthopedic procedures, while the leading procedures for OBS settings were colonoscopy, biopsy of the prostate, and angioplasty [2]. Minor complications occurred in 11.2 percent of cases performed in OBS settings versus 17 percent in ASC settings (95% CI 5.2-7.0). Major complications (defined as overt adverse events primarily involving the airway or cardiopulmonary systems) were very rare in both settings (0.24 percent in OBS versus 0.07 percent in ASCs; 95% CI -0.15 to 0.04). Despite the limitations of this study, effective risk mitigation and patient safety in OBS were demonstrated.

Anesthesia databases and registries for other nonoperating room anesthetizing locations have noted that major complications are most commonly due to respiratory compromise, aspiration events, and dental injuries [29]. (See "Considerations for non-operating room anesthesia (NORA)".)

PATIENT SELECTION — Selection of appropriate patients for office-based anesthesia is an important decision that is made jointly by surgeons and anesthesiologists [1]. A gradual transition to performing office-based procedures in more medically complex patients has occurred, which may increase patient and provider liability risks [1,8,30]. Although the ideal patient for an office-based procedure has an American Society of Anesthesiologists (ASA) physical status (PS) classification of I or II (table 4), approximately one-third of patients served in this setting were ASA PS III [2].

Use of a detailed screening questionnaire completed by the patient may help to ensure a thorough risk assessment [31]. Subsequently, review of the patient's medical records includes evaluation for medical conditions that may confer unacceptable risk in an office-based setting [10,32]. Since nearly all office-based procedures are elective, the anesthesiologist has time to consider whether medical management of certain conditions is optimal (eg, asthma, anemia) before surgery. All appropriate testing should be completed and available before or on the day of the scheduled procedure. (See "Preoperative evaluation for anesthesia for noncardiac surgery" and "Preoperative medical evaluation of the healthy adult patient".)

The demand for office-based procedures for patients with challenging comorbidities may exceed the qualifications of some office-based surgical (OBS) teams, particularly if there would be limited availability of additional personnel for management of an emergency. Thus, higher-risk patients or procedures should ideally be performed in facilities that are formally accredited (eg, by the American Association for Accreditation of Ambulatory Surgical Facilities or the Accreditation Association For Ambulatory Health Care), and should be performed by board-certified surgeons who are credentialed for the same procedures at a local hospital [1,33-37]. (See 'Government regulations' above.)

Identification of poor-risk patients — Identifying patients at higher risk for complications during anesthesia and surgery is important. In some cases, ensuring optimal medical treatment may reduce risk [10]. In other cases, the patient should be referred to a facility able to handle complications that may occur [16].

In a retrospective study of more than 1.4 million ambulatory surgery patients in Massachusetts and New York states, comorbidities that predicted a higher likelihood of unplanned hospital admission include persons with obesity, malignancy, drug abuse, moderate or severe renal failure, deficiency anemia, depression, congestive heart failure, liver disease, peripheral vascular disease, diabetes, and chronic pulmonary disease [38]. Other examples of high-risk abnormalities or conditions include a potentially difficult airway, obstructive sleep apnea, recent myocardial infarction within the past six months or recent stroke within the past three months, sickle cell disease, abnormal bleeding or clotting tendency, inability to cooperate due to severe anxiety or poorly controlled psychiatric problems, history of anaphylaxis, or family history of malignant hyperthermia (MH) [1,10,39-41]. General perioperative considerations for these and other comorbidities are summarized in our topic addressing preanesthetic evaluation for noncardiac surgery (see "Preoperative evaluation for anesthesia for noncardiac surgery", section on 'Conditions that increase perioperative risk'), and detailed discussions for each abnormality or disease can be found in various UpToDate topics.

Other reasons for rescheduling procedures — Other factors that may prompt rescheduling of an otherwise suitable patient on the day of surgery include active infection, acute exacerbation of a comorbid condition, failure to abstain from ingestion of food or clear liquids for an appropriate amount of time (table 5) (see "Preoperative fasting in adults"), suspicion of acute substance intoxication, or absence of a planned escort for transport after discharge.

PROCEDURE SELECTION — The planned procedure is a factor in determining whether a patient can safely undergo surgery in an office-based setting [1,10,11,42]. Examples of procedures that are often performed in this setting include selected liposuction procedures; aesthetic facial and breast surgery; ophthalmologic procedures; oral, maxillofacial, otolaryngology, and complex dental procedures; gastrointestinal endoscopy; gynecologic procedures; orthopedic and podiatry procedures; and endovascular or other vascular procedures [1,11]. (See 'Anesthetic considerations and outcomes for selected procedures' below.)

The surgeon/proceduralist and the anesthesiologist are jointly responsible for determining whether the following conditions are met [1]:

●The procedure is within the surgeon's scope of practice and the facility's capabilities.

●The duration and degree of complexity of the procedure allow for recovery and discharge from the facility on the same day [16]. For example, the American Society of Plastic Surgery has recommended that office-based procedures be limited to six hours, and be completed by 3:00 PM, as long as the office remains fully staffed until a later hour to meet patient recovery needs [43]. As newer surgical and anesthetic techniques have been developed, longer and more complicated procedures have been performed in office-based settings. However, duration has been correlated with a higher incidence of unplanned hospital admission as well as increased incidence of postoperative nausea and vomiting (PONV), pain, and bleeding [44,45]. In a retrospective study of more than 1.4 million ambulatory surgery patients in Massachusetts and New York states, procedural categories with a higher likelihood of unplanned hospital admission included vascular, mediastinal, pulmonary, urinary, nervous system, gastrointestinal, endocrine, lymphatic, and musculoskeletal surgery [38].

Surgical procedures that are not appropriate for the office setting include those associated with major fluid shifts or blood loss that may require transfusion, and those expected to result in moderate to severe postoperative pain, particularly if postoperative opioid administration may be necessary. (See 'Recovery and discharge' below and 'Local or regional anesthetic techniques' below.)

ANESTHETIC MANAGEMENT — As with any ambulatory setting, the anesthetic goals for a patient having office-based surgery (OBS) are safety and rapid recovery from the effects of anesthetic agents, minimal side effects, and rapid discharge from the office facility [10].

Standard monitors — In all office-based procedures, standard American Society of Anesthesiologists (ASA) monitoring is necessary (ie, pulse oximetry, electrocardiogram, blood pressure, capnography, temperature) (table 6). (See "Basic patient monitoring during anesthesia", section on 'Standards for monitoring during anesthesia'.)

Choice of anesthetic techniques — Anesthetic techniques suitable for OBS procedures include sedation at minimal, moderate, or deep levels, general anesthesia, and regional anesthetic techniques. The choice of technique depends on the procedure and the preferences of the surgeon, patient, and anesthesiologist. Whether any particular anesthetic technique (eg, deep sedation or general anesthesia) is less safe in the office-based setting has been debated [33,34,46]. Most studies support the safety of general anesthesia as well as other techniques [1,4,5,7,11,35,37,47-49].

Although minimal, moderate, or deep sedation (with or without local anesthesia) are common techniques, general anesthesia occurs along a continuum (table 7) [10]. Thus, the anesthesiologist must be able to "rescue" the patient from an anesthetic level that becomes deeper than originally intended to avoid hypoxia or aspiration [29,50]. (See "Monitored anesthesia care in adults".)

Although not specific for office-based anesthesia, a closed claims analysis of monitored anesthesia care (MAC) claims is relevant for many office-based procedures [51]. Compared with claims for general anesthetic cases, MAC claims involved older and sicker patients in that analysis. Severe respiratory depression was identified as the most common cause of injury [51]. Similar to general anesthesia, 40 percent of the claims were related to permanent brain damage or death and were deemed preventable in 46 percent (eg, by improved vigilance of the practitioner, better monitoring, and/or more reliable anesthesia alarms).

Selection of anesthetic agents — Ideal anesthetic agents for use in an office-based setting will have a short duration of action, absence of postoperative nausea and vomiting (PONV), and are cost-effective.

Short duration — To facilitate rapid discharge after the procedure (ideally, one hour or less), only short-acting agents are used to produce either sedation (eg, propofol, ketamine, midazolam, dexmedetomidine) or general anesthesia (eg, propofol, ketamine, dexmedetomidine, and/or inhalation agents such as nitrous oxide, sevoflurane or desflurane) [10]. Short-acting opioids may be used to provide analgesia (eg, fentanyl or remifentanil).

Many anesthesiologists use nitrous oxide in combination with intravenous agents or with a volatile anesthetic agent. Nitrous oxide reduces the doses of other agents and may reduce costs and expedite emergence from anesthesia because of its rapid offset [52,53]. (See "Maintenance of general anesthesia: Overview", section on 'Nitrous oxide gas' and "Inhalation anesthetic agents: Clinical effects and uses", section on 'Nitrous oxide'.)

Avoidance of postoperative nausea and vomiting — Minimizing PONV is a major consideration in any ambulatory surgery setting [54-56]. Since the incidence of PONV after outpatient surgery may be as high as 50 percent, we use a multimodal approach to both prophylaxis and treatment. In patients at risk for PONV, we employ a variety of antiemetic agents targeting different receptors, as well as anesthetic and analgesic techniques that do not cause PONV. Depending on patient-specific risks for PONV, prophylactic drugs may include scopolamine (an anticholinergic worn as a patch), and/or intravenous agents such as dexamethasone (a steroid with a central antiemetic mechanism), and/or ondansetron (a 5-hydroxytryptamine [5-HT] inhibitor). (See "Postoperative nausea and vomiting", section on 'Prevention'.)

Anesthetic techniques to minimize PONV include use of total intravenous anesthesia, usually with propofol alone or in combination with an opioid [54]. Also, dexmedetomidine may be used as an adjunct anesthetic agent because this alpha-2 agonist provides some analgesia and sedation. Other techniques include use of neuraxial anesthesia (spinal or epidural) or peripheral nerve blocks with or without catheters. Furthermore, opioid-sparing analgesics are used when feasible (eg, acetaminophen and/or nonsteroidal antiinflammatory drugs [NSAIDs]). (See "Postoperative nausea and vomiting", section on 'Anesthetic factors' and "Postoperative nausea and vomiting", section on 'Reduction of baseline risk'.)

Ensuring adequate hydration may be useful in prevention of PONV by avoiding orthostatic hypotension and consequent decreased blood flow to the midbrain emetic centers [39]. For most healthy adult patients undergoing minimally invasive relatively short outpatient surgical procedures that are not associated with significant fluid shifts or blood loss, 1 to 2 L of a balanced electrolyte crystalloid solution is administered during surgery. Such empiric fluid administration addresses the mild dehydration caused by preoperative fasting, and is associated with less PONV as well as less postoperative pain [54]. (See "Intraoperative fluid management", section on 'Crystalloid solutions' and "Intraoperative fluid management", section on 'Minimally/moderately invasive surgery'.)

In the postoperative period, rescue treatment for patients who develop PONV should include a drug from a different class than any that have already been administered, unless the effect of the first drug has worn off or a potentially inadequate dose has been administered. Serotonin receptor antagonists such as ondansetron are particularly useful as rescue agents, especially for same-day surgery patients, because they are nonsedating. In rare cases, it may be necessary to admit a patient with persistent severe PONV to an inpatient facility. (See "Postoperative nausea and vomiting", section on 'Rescue therapy'.)

Cost-effectiveness — Cost is a valid but lesser concern in selection of anesthetics. Cost is balanced against potential side effects such as PONV and delayed recovery that might negate cost advantages for certain agents and techniques [57,58].

Local or regional anesthetic techniques — Peripheral nerve blocks have been employed for many procedures to decrease the need for deep sedation, general anesthesia, and opioid use. (See "Overview of peripheral nerve blocks".)

Maximum allowable doses of local anesthetic agents that appear in various publications are rough guidelines that are not evidence-based, and don't take into account the site or technique of administration, or patient factors that increase toxicity risk (table 8) [5,59]. Furthermore, calculated doses should be based on lean, rather than actual body weight (calculator 1 and calculator 2). Addition of epinephrine to local anesthetic solutions can slow the rate of absorption and reduce peak plasma levels, but do not prevent systemic toxicity in all patients.

It is critically important that the anesthesiologists, surgeons, and nurses managing perioperative care are well-versed in the signs and symptoms of systemic local anesthetic toxicity in this setting (table 9) [59]. Office-based facilities should have appropriate equipment for monitoring the patient and managing adverse events in any location where nerve blocks are placed. Emergency drugs and equipment must be immediately available to manage allergic reactions, systemic toxicity of local anesthetics (seizures and/or cardiovascular collapse), or rapid cephalad progression of anesthetic level due to unintended intrathecal injection or epidural spread (table 1). Less severe adverse effects of regional anesthesia include postdural puncture headache or nerve damage that may result in a hospital admission. Details regarding recognition and treatment of regional anesthesia complications are discussed in separate topics:

●(See "Local anesthetic systemic toxicity".)

●(See "Overview of peripheral nerve blocks", section on 'Complications'.)

●(See "Overview of neuraxial anesthesia", section on 'Adverse effects and complications'.)

POSTOPERATIVE PAIN CONTROL — Optimal pain management often involves a multimodal approach that includes combinations of drugs and techniques [60]. Although opioid medications have been a mainstay in perioperative pain management and are effective in the acute setting, unwanted side effects that are particularly undesirable in the outpatient setting include nausea and vomiting, itching, constipation, respiratory depression, and altered mental status, as well as possible dependence and tolerance issues. Thus, we use parenteral and/or enteral nonopioid analgesics to reduce opioid requirements. These include acetaminophen and nonsteroidal antiinflammatory drugs (NSAIDs) such as ketorolac, ibuprofen, or celecoxib (table 10). When appropriate, we also use regional techniques and long-acting local anesthetics (eg, bupivacaine or ropivacaine with peripheral nerve blocks or liposomal bupivacaine for wound infiltration). Other techniques include high-volume local infiltration analgesia [61] and delivery of local anesthetics through wound catheters [62]. (See "Approach to the management of acute pain in adults", section on 'Strategy based on expected degree and duration of pain' and "Approach to the management of acute pain in adults", section on 'Options for managing postoperative analgesia'.)

RECOVERY AND DISCHARGE — Safe recovery and discharge depend on the office-based staff's ability to deliver appropriate intensity and duration of postoperative monitoring. Complications such as respiratory events (the most common mechanism of injury), delayed emergence from anesthesia, pain, nausea/vomiting, urinary retention, and hypothermia must be recognized and treated. (See "Overview of post-anesthetic care for adult patients".)

Discharge criteria are designed to determine a patient's readiness to safely leave the office recovery area after surgery (table 11). Fully trained nurses should be available to care for all postoperative patients until discharge. Ideally, an anesthesiologist should assess each patient prior to release to home. (See "Overview of post-anesthetic care for adult patients", section on 'Discharge from the post-anesthesia care unit'.)

In a closed claims analysis of office-based settings compared with other ambulatory anesthesia settings, a greater proportion of injuries were judged to be preventable by better monitoring, particularly in the postoperative period [63].

ANESTHETIC CONSIDERATIONS AND OUTCOMES FOR SELECTED PROCEDURES — Most literature reviews of adverse outcomes and mortality after various types of office-based surgical (OBS) procedures have concluded that surgery in this setting is safe and cost-effective [1,7,8,10,21,42,60,64]. Improvements in patient outcomes are likely due to implementation of more stringent credentialing and accreditation regulations, as well as use of routine safety checklists and emergency manuals, as discussed above [1,25]. (See 'Safety concerns' above.)

Considerations and outcomes for specific procedures are noted below.

Cosmetic surgical procedures

Liposuction — Liposuction is accomplished by inserting hollow rods into small skin incisions, to suction subcutaneous fat into an aspiration canister. Either general anesthesia, moderate-to-deep sedation, or minimal oral sedation techniques have been used (table 7) [43,46]. This tumescent technique uses large volumes (eg, 1 to 4 mL for each 1 mL of fat to be removed) of an infiltrate solution such as 0.9% saline or Ringer's lactate with epinephrine 1:1,000,000 and lidocaine 0.025 to 0.12%.

Since the large injectate volumes that are employed may result in hypervolemia, close attention to fluid and electrolyte balance is particularly important in the intraoperative and postoperative periods [10,39]. Patients are also at risk for hypothermia because the injectate fluids are not typically warmed. Active warming devices (eg, forced air warmers) are used in many plastic surgery offices to avoid and treat hypothermia [10]. We agree with the guidelines of the American Society of Plastic Surgeons stating that the total volume of aspirant, including supernatant fat and fluid, should be limited to 5000 mL if the liposuction procedure is performed in isolation, or 2000 mL if performed with a concurrent aesthetic surgical procedure [10,42,43]. Body mass index is taken into account; the volume of aspirate removed should be proportional to the patient's overall size [65]. Generally, aspirate volumes >5000 mL are performed in an acute-care hospital or licensed/accredited facility due to increased risk of complications [65].

The dose of epinephrine in the infiltrate solution used for the tumescent technique should not exceed 0.07 mg/kg (eg, <5 mg in a 70 kg patient) to minimize risk for cardiovascular effects [10]. Although epinephrine is rapidly metabolized with a half-life of approximately two minutes, sustained peak levels have been demonstrated during and after tumescent liposuction, possibly due to local vasoconstriction that results in delayed or reduced systemic absorption. One small study in five patients undergoing tumescent liposuction noted epinephrine peak blood concentrations ranging from 5.8 to 9.7 mg (0.08 to 0.12 mg/kg) one to four hours after injection, with return to baseline levels after approximately 20 hours [66]. The total amount of absorbed epinephrine that was estimated for each patient ranged from 1.8 to 2.2 mg (equivalent to 25 to 32 percent of the infiltrated dose). Although none of the participants in this study exhibited any signs of toxicity after exposure to these high epinephrine doses, timing for presentation of catecholamine toxicity is unpredictable since drug absorption is variable. Severe reactions have been reported during or after subcutaneous epinephrine doses as low as 3 mg [67].

Also, the dose of lidocaine in the infiltrate solution used for the tumescent technique is typically 35 to 55 mg/kg, which is considerably higher than the 4.5 mg/kg maximum recommended dose for regional anesthetic techniques [68-70]. These high doses are usually well-tolerated because the tumescent technique results in single compartment clearance, similar to that of a sustained-release medication [68,71]. However, absorption of local anesthetic from the subcutaneous tissue is variable; thus, timing for onset of symptoms of lidocaine toxicity is unpredictable [70,72]. Although blood lidocaine levels typically peak 12 to 16 hours after initial injection of infiltrate solution, peaks may occur within two hours of injection, particularly if tumescent lidocaine without epinephrine is used (eg, for endovenous laser therapy). Thus, close postoperative monitoring in the office-based recovery area is necessary, and lipid emulsion should be immediately available for prompt treatment (table 9) [70,71]. (See "Local anesthetic systemic toxicity", section on 'Lipid rescue'.)

Since blood lidocaine levels are slowly absorbed and typically peak 12 to 16 hours after injection, the patient may not show signs of systemic local anesthetic toxicity (eg, dizziness, peripheral numbness, metallic taste, tinnitus, confusion/anxiety, seizures) until after discharge home. This is clinically relevant because signs of local anesthetic toxicity must be rapidly recognized, and appropriate emergency procedures initiated [73,74]. All patients and their caregivers should receive instructions regarding the need to seek emergency department care immediately if signs or symptoms of local anesthetic toxicity become apparent after discharge. (See "Local anesthetic systemic toxicity", section on 'Clinical presentation of toxicity'.)

Liposuction has been considered to be a high-risk office-based procedure with reported perioperative deaths attributed to anesthetic complications, abdominal viscus perforation, fat embolism, hemorrhage, and unknown causes [75,76]. Liposuction is particularly risky when combined with other procedures such as abdominoplasty [77,78]. However, a 2019 meta-analysis that included 20 observational studies and >700,000 liposuction procedures noted that there were no reported deaths and only four serious adverse events (cardiac arrhythmia requiring treatment) when liposuction was performed in nearly 24,000 procedures (four studies) with tumescent local anesthesia that included no or only minimal systemic anesthesia (ie, moderate-to-deep sedation or general anesthesia) [46]. In this meta-analysis, office-based liposuction procedures had lower rates of adverse events than those performed in a hospital setting. (See "Obesity in adults: Overview of management".)

Other cosmetic surgery — Other plastic surgical procedures that may be performed in an office-based setting with monitored anesthesia care (MAC) or deep sedation, or occasionally with general anesthesia, include facial cosmetic surgery (eg, blepharoplasty, rhinoplasty, facelift), breast procedures, and abdominoplasty.

In a prospective cohort review evaluating the safety of cosmetic surgery performed between 2008 and 2013 on the body, breast, face, or combination of regions in more than 129,000 patients (having a total of nearly 184,000 procedures), 15.9 percent were performed in an accredited office-based setting by board-certified plastic surgeons, rather than in an ambulatory surgery center (ASC) setting (57.4 percent) or hospital (26.7 percent) [7]. Complication rates, including hematomas, infections, and postoperative pulmonary dysfunction, were lowest in the office-based setting (1.3 percent), compared with the ASC setting (1.9 percent), or the hospital setting (2.4 percent). In a 2018 retrospective review of 174 patients undergoing primary facelift under local anesthesia with oral sedation in an office-based setting, no mortality was reported, and complications were minor (primarily hematoma formation [13 percent], with only two patients requiring operative evacuation) [79]. Older retrospective studies of cosmetic surgery performed in an office-based setting have noted similar low risks of significant complications [35,37,48,49,80-82]. Taken together, these studies suggest that accredited OBS suites are generally a safe alternative to ASCs or hospitals for cosmetic surgical procedures. However, careful patient selection is necessary, as noted above. (See 'Patient selection' above.)

In analyses of adverse incidents occurring during OBS in Florida between 2000 and 2003, there were 13 procedure-related deaths, with seven involving elective cosmetic procedures, five of which were performed under general anesthesia [33,34]. A subsequent study noted mandatory reports of 31 deaths in Florida during office-based plastic surgery over the seven-year period from 2000 to 2007 [75].

In particular, fire and facial burns are a particular risk for any facial procedure that requires use of a laser, or even routine electrocautery, due to the presence of supplemental oxygen (or nitrous oxide) in combination with combustible substances such as paper drapes and alcohol prep [39]. Thus, nitrous oxide should not be used, and, when possible, avoidance of supplemental oxygen is ideal (see "Fire safety in the operating room"). In a study MAC conducted by the American Society of Anesthesiologists (ASA) using a closed claims database, many of the patients were undergoing facial surgery [51]. Severe respiratory depression was identified as the most common cause of injury in all MAC cases (21 percent), followed by facial burn injuries in the presence of supplemental oxygen during facial surgery (17 percent) [51]. Thus, these cases are among the highest-risk procedures performed in the office setting [10].

Also, patients undergoing abdominoplasty may be at greater risk for later postoperative complications such as venous thromboembolism and emergency department or hospital admission, particularly if the procedure is performed concurrently with other cosmetic surgery (eg, liposuction, breast procedures) [78,83].

Ophthalmology procedures — Cataract surgery is one of the most common procedures requiring office-based anesthetic care; glaucoma and vitreoretinal surgical procedures are often performed in this setting as well [11]. Details regarding anesthetic management and potential complications of these procedures are available in a separate topic. (See "Anesthesia for elective eye surgery".)

Oral and maxillofacial procedures — Oral, maxillofacial, and other head and neck surgical procedures that are not complex (eg, tonsillectomy, nasal or intranasal procedures) may be performed in an office-based setting [5].

In one large prospective cohort study of more than 34,000 patients undergoing oral or maxillofacial surgery in this setting, 72 percent received deep sedation or general anesthesia, 15.5 percent received conscious sedation, and 12.5 percent received local anesthesia [47]. There were no deaths in this large study, and only two patients in this study had complications requiring hospitalization, while 94 percent reported satisfaction with the anesthetic.

Additional details regarding anesthetic management and potential complications of head and neck procedures are available in separate topics. (See "Anesthesia for head and neck surgery".)

Otolaryngology procedures — Selected otolaryngology procedures can be performed in an office-based setting [5]. Local or topical anesthesia can be used to anesthetize the immediate surrounding tissues of the surgical bed or as an injection for regional cutaneous nerve blockade for many otolaryngology surgical procedures. One small study of middle ear surgery (ossiculoplasty) performed under local anesthesia in selected adult patients in this setting noted no postoperative nausea, vomiting, dizziness, or other complications [84]. Interactive and immersive virtual reality techniques have been used as an adjunct to topical anesthesia to reduce pain and anxiety in an office-based setting [85].

As with other facial surgery, close attention must be paid to maximum allowable doses of local anesthetic agents (table 8) [5,59], and to risks of fire. (See 'Local or regional anesthetic techniques' above and "Fire safety in the operating room".)

Dental procedures — Dental procedures are commonly performed in an office-based setting [11]. In a retrospective review that included 1323 selected patients receiving sedation or general anesthesia, there were only three events resulting in unplanned hospital transfers (annual incidence 0.07 percent) [86]. These included one acute hypertensive crisis with pulmonary edema, one potentially missing dental swab requiring radiographic confirmation of its absence, and one failure of a caregiver to return for patient transport after discharge. (See "Complications, diagnosis, and treatment of odontogenic infections".)

Gastrointestinal endoscopic procedures — Gastrointestinal endoscopy procedures are commonly performed in an office-based setting. Details regarding anesthetic management and potential complications for patients undergoing gastrointestinal endoscopy are discussed in a separate topic. (See "Anesthesia for gastrointestinal endoscopy in adults".)

Gynecologic procedures — Termination of pregnancy (ie, abortion) is commonly performed in an office-based setting. In a 2018 retrospective study that included more than 50,000 such procedures, no differences in abortion-related adverse events were noted in this setting compared with ASC settings [87]. Details regarding these procedures and potential complications are available in a separate topic. (See "Overview of pregnancy termination".)

Other gynecologic procedures such as cervical or endometrial biopsy, curettage, and hysteroscopy, insertion of intra-uterine devices (IUDs), and egg retrievals for fertility treatments have also safely been performed in the office-based setting.

Orthopedic and podiatry procedures — Selected orthopedic procedures have been performed in an office-based setting. Examples include diagnostic arthroscopy for knee and shoulder intraarticular injuries [88]. One study of office-based kyphoplasty for treatment of vertebral compression fractures reported use of local anesthesia and oral sedation in 99 consecutive patients with zero intraoperative complications [89]. Other outpatient orthopedic surgical procedures that are being evaluated in ASCs include shoulder arthroscopy with subacromial decompression and distal clavicle resection, knee arthroscopy with anterior cruciate ligament repair, open reduction and internal fixation of bimalleolar ankle fracture, open reduction and internal fixation of distal radius fracture, knee arthroscopy with medial and lateral meniscectomy, total knee arthroplasty, and one level lumbar laminectomy [90].

Although many podiatry procedures are performed in office-based settings, published research regarding sedation or anesthesia for such cases is scant.

Endovascular and other vascular procedures — Selected endovascular procedures such as infrapopliteal interventions, as well as diagnostic arteriograms, arterial or venous interventions, dialysis access, and venous catheter management can be safely performed in an office-based setting [91,92]. (See "Overview of vascular intervention and surgery for vascular anomalies".)

OFFICE-BASED PROCEDURES DURING THE COVID-19 PANDEMIC — While only urgent and emergency surgical and other interventional procedures were performed initially during the novel coronavirus disease 2019 (COVID-19) pandemic, elective procedures, including office-based procedures, have been resumed in many institutions. In fact, patients may be more apt to return to the outpatient setting to avoid the hospital, especially when there are local resurgences of COVID-19 cases [93]. Strategies to minimize infection risks during anesthesia and surgery vary according to local resources and institutional protocols [25,93,94]. Details regarding preoperative planning and intraoperative management during the COVID-19 pandemic are available in separate topics. (See "COVID-19: Perioperative risk assessment, preoperative screening and testing, and timing of surgery after infection" and "Overview of infection control during anesthetic care", section on 'Infectious agents transmitted by aerosol (eg, COVID-19)' and "Overview of infection control during anesthetic care", section on 'Prevention of contamination of anesthesia machines and equipment'.)

SUMMARY AND RECOMMENDATIONS

●Potential benefits – The number of elective surgical procedures performed in an office-based setting has expanded rapidly. Compared with hospital settings, the major advantages of office-based anesthesia for surgical procedures are patient and surgeon convenience, cost containment, and possibly lower nosocomial infection rates. (See 'Potential advantages and benefits' above.)

●Safety concerns – Safety concerns have centered around the adequacy of individual facility resources and governmental regulations for office-based facilities, and ensuring that compliance with all applicable federal and state laws, codes, and regulations has been achieved (table 2 and table 1). We use guidelines for office-based anesthesia adopted by the American Society of Anesthesiologists (ASA), including standard monitoring (table 6). We also use a routine checklist (form 1 and table 3), as well as crisis checklists to further ensure patient safety. (See 'Safety concerns' above.)

●Patient selection – Patients at higher risk for complications during anesthesia and surgery are identified preoperatively. Examples include persons with obesity, a potentially difficult airway, obstructive sleep apnea, severe or exacerbated chronic obstructive pulmonary disease, recent myocardial infarction within the past six months or recent stroke within the past three months, end-stage kidney or liver disease, severe anemia, sickle cell disease, abnormal bleeding or clotting tendency, extremes of age, acute or chronic substance abuse, inability to cooperate due to severe anxiety or poorly controlled psychiatric problems, history of anaphylaxis, or family history of malignant hyperthermia (MH). In some cases, ensuring optimal medical treatment may reduce risk, but in other cases, the patient should be referred to a facility that can handle complications that may occur. (See 'Patient selection' above.)

●Procedure selection – The surgeon/proceduralist and the anesthesiologist are jointly responsible for determining whether the following conditions are met (see 'Procedure selection' above):

•The procedure is within the surgeon's scope of practice and the facility's capabilities

•The duration and degree of complexity of the procedure will allow recovery and discharge for the facility on the same day

Procedures generally inappropriate for office-based surgery (OBS) include those associated with a prolonged duration (more than six hours), significant blood loss or fluid shifts, or moderate-to-severe postoperative pain.

●Specific procedures – Anesthetic considerations and outcomes for selected procedures are discussed above and in separate topics (see 'Anesthetic considerations and outcomes for selected procedures' above):

•(See 'Liposuction' above.)

•(See 'Other cosmetic surgery' above.)

•(See "Anesthesia for elective eye surgery".)

•(See 'Oral and maxillofacial procedures' above.)

•(See 'Otolaryngology procedures' above.)

•(See 'Dental procedures' above.)

•(See "Anesthesia for gastrointestinal endoscopy in adults".)

•(See 'Gynecologic procedures' above.)

•(See 'Orthopedic and podiatry procedures' above.)

•(See 'Endovascular and other vascular procedures' above.)

●Choice of anesthetic technique – Minimal, moderate, or deep sedation, general anesthesia, or local/regional anesthetic techniques are each suitable for appropriately selected OBS procedures. (See 'Choice of anesthetic techniques' above.)

●Selection of short-acting agents – To facilitate a rapid discharge after the procedure, only short-acting anesthetic agents are used to produce either sedation or general anesthesia. Similarly, short-acting opioid agents are used to control pain. (See 'Selection of anesthetic agents' above.)

●Avoidance of postoperative nausea, vomiting, and pain – We use a multimodal approach to avoid and/or treat:

•Postoperative nausea and vomiting (PONV). This approach may include multiple drugs targeting different receptors, alternate anesthetic techniques (eg, total intravenous anesthesia with propofol, regional anesthesia), adequate hydration, and nonopioid analgesics, particularly in patients at high risk for PONV. (See 'Avoidance of postoperative nausea and vomiting' above.)

•Postoperative pain. Avoidance and management may include combinations of drugs (eg, nonopioid analgesics) and techniques (eg, long-acting local anesthetics). (See 'Postoperative pain control' above.)

●Postoperative recovery and discharge – Safe recovery and discharge depend on the office-based staff's ability to deliver appropriate intensity and duration of postoperative monitoring. Complications such as respiratory events, delayed emergence from anesthesia, pain, PONV, urinary retention, and hypothermia must be recognized and treated. Standard discharge criteria are used to supplement the assessment of the responsible anesthesiologist for release home (table 11). (See 'Recovery and discharge' above.)