Office-Based Anesthesia



Office-Based Anesthesia


Laurence M. Hausman

Meg A. Rosenblatt






Office-based anesthesia (OBA) is a subset of both nonoperating room anesthesia (NORA; see Chapter 32) and ambulatory anesthesia (see Chapter 30). NORA refers to any anesthetic that takes place outside of the traditional operating room but usually within a fully licensed hospital. Examples of NORA locations include an endoscopy suite, an invasive radiology suite, a magnetic resonance imaging (MRI) machine or an area in which electroconvulsive therapy (ECT) takes place. Alternatively, an ambulatory anesthetic is one in which the patient arrives to the surgical venue the day of the procedure, is anesthetized, and is discharged home later that same day.

An office-based anesthetic is defined as an anesthetic that is performed in an outpatient venue such as an office or procedure room that is not accredited as either an ambulatory surgery center (ASC) or as a hospital. In contrast to an ASC, the office provides practitioners with the space for other activities such as consultation with new patients, the performance of routine history and physicals, and office administration. In addition, while ASCs are often multidisciplinary, office-based practices are generally confined to one specialty such as urology, gastroenterology, plastic surgery, or dentistry.1,2

Although an OBA practice may be an exciting alternative to the traditional hospital-based one, it requires the anesthesiologist to expand his or her role within the health-care delivery system. Along with providing safe anesthetics across the spectrum of healthy to medically challenged patients undergoing increasingly complex procedures, the anesthesiologist must understand office safety and policy, legal and financial issues such as antitrust laws, and billing and collection issues.3 These are relatively new responsibilities for the anesthesiologist, who has previously worked as a member within a hospital department either in a private or academic setting. A further challenge to the office-based practitioner is that presently there is little to no training in OBA within the anesthesia residency curriculum.4


Brief Historical Perspective of Oba

There have been reports of office-based surgery and anesthesia since the mid-nineteenth century. In 1856, John Snow documented his experience in providing anesthesia with chloroform for 867 dental patients, and approximately 3,021 teeth were extracted in private dental offices under his care.5 Throughout history, the family physician performed house calls and numerous small surgical procedures such as the lancing of boils and repair of wounds were conducted within the comfort of the patient’s home. The physician’s private medical office was, likewise, utilized in the service of this type of surgical care.

As surgery became more invasive, the need for intensive perioperative physiologic monitoring became increasingly necessary. The capacity to administer blood products and the development of an extensive array of pharmaceutical agents began to play a role in patient care, fostering the growth of larger health-care delivery teams to assist in patient care. Thus, over time, the inpatient hospital became the primary setting in which surgery would be performed.

Over the past several decades, as a result of both surgical and anesthetic advances, the surgical experience has again changed. Through innovations such as laparoscopic techniques, surgery has become increasingly less invasive and less painful. In addition, newer anesthetics have the benefit of “fast-acting” profiles (associated with quick onsets and rapid termination of effect) and with fewer hemodynamic side effects, lending increasing number of procedures to be suitable for the performance in outpatient venues.6,7

During the 1970s, less than 10% of all surgical and diagnostic procedures were performed on an ambulatory basis and of these, virtually all were performed in hospitals. By 1987, approximately 25 million, or 40% of all procedures, were performed as ambulatory. In the United States, between 1984 and 1990, the number of office-based procedures increased from 400,000 to 1.2 million, and by 1994, 8.5% of all procedures were performed in offices.8 In 1994, a landmark survey of the membership of the American Society of Plastic Surgeons (ASPS), revealed that 55% of the respondents performed the majority or all of their procedures in an office.9 In the year 2000, approximately 75% of all procedures were performed on an outpatient basis; 17% in freestanding ASCs, and 14% to 25% (approximately 8 to 10 million) in physicians’ offices.10,11,12 By 2005, the American Hospital Association reported that while 82% of all procedures were performed on an ambulatory basis, 16% of all these ambulatory procedures were performed in private offices.13


Advantages/Disadvantages

There are many advantages to an office-based procedure when compared to a traditional hospital-based one, and the most obvious of these advantages is cost containment. Several components make up the actual cost of a given surgical procedure. In addition to the professional fees of both the proceduralist and the anesthesiologist (which are usually negotiated prior to an elective procedure), there is a facility fee charged by the hospital or ASC. This fee generally covers the associated costs to the hospital/ASC, and includes overhead such as maintenance, equipment, and staffing. It often constitutes a large component of the patient’s overall charge. In an office, this amount can easily be predicted and is often minimal when compared to that in a hospital. The reason for this discrepancy is that while the overhead costs in a small office are usually quite reasonable and managed, the comparable costs in a large tertiary care hospital can be both enormous and unpredictable.10,11,14

In 1994, Schultz determined the cost of an in-hospital laparoscopic inguinal hernia repair to be $5,494. When the same procedure was performed in an office, the price was decreased to $1,533.84. Similarly, the average cost of an in-hospital open inguinal hernia repair was found to be $2,237, while the same procedure performed in a private office cost $894.79.15 In addition, Bartamian16 reported that office-based ocular surgery, performed under monitored anesthesia care (MAC), can cost 70% less than similar procedures performed in a hospital. Some insurance companies now offer incentives to surgeons who utilize an office location as their surgical venue.17

Other clear advantages of office-based procedures include ease of scheduling (often with less paperwork), patient and surgeon convenience, decreased patient exposure to nosocomial infections, and both improved patient privacy and continuity of care (since an office is usually staffed by a small consistent group of personnel).3,11,18,19

There are potential disadvantages to an office-based procedure which relate to issues regarding patient safety and peer review.20 In some parts of the country, no regulations governing office-based surgery and OBA exist. Therefore, there may be little to no oversight regarding the certification/qualification of either the surgeon or anesthesiologist to perform the intended procedures, the surgical office’s policy regarding peer review, performance improvement, documentation, general policies and procedures,
and the reporting of adverse outcomes. However, the number of such states without regulation and oversight is rapidly decreasing21 (Table 31-1).








Table 31-1. States which have Regulations Regarding Office-Based Surgery and Anesthesia









































Alabama Mississippi
Arizona New Jersey
California New York
Colorado North Carolina
Connecticut Ohio
District of Columbia Oklahoma
Florida Oregon
Illinois Pennsylvania
Indiana Virginia
Kansas South Carolina
Kentucky Tennessee
Louisiana Texas
Massachusetts Washington


Office Safety

Media reports and newspaper articles raised the earliest questions regarding the safety of office-based procedures.22 These exposes in the lay press may be legitimate. It has been reported that there may, in fact, be an increased risk of injury during an office-based anesthetic secondary to the remote location of an office.23

Data reveal that injuries and deaths occurring in offices are often multifactorial in causation. Reasons include over-dosages of local anesthetics, prolonged surgery with occult blood loss, pulmonary embolism, accumulation of multiple anesthetics resulting in over-sedation, hypovolemia, hypoxemia, and the use of reversal drugs with short half lives.24,25,26 Both the American Society of Anesthesiologists (ASA)and the Anesthesia Patient Safety Foundation27,28 have emerged as leaders in the field of OBA safety and have advocated that the quality of care in office-based practice be no less than that of a hospital or ASC. Thus, it is imperative to ensure that all safety precautions one may take for granted in a hospital be present in the surgical office.

In 1990, the mortality rate from anesthesia was approximately 1/100,000. By the year 2000, the rate had decreased to 1/250,000 in hospitals and 1/400,000 in free-standing ASCs.29 Although the interpretation of these figures is open to debate, the decrease in mortality can be attributed, in part, to improvements in the training of the anesthesia providers, the safety profiles of the newer anesthetics, improved perioperative monitoring capabilities and intrinsic safety mechanisms in place within the anesthetizing location. Since the majority of office-based patients are young and healthy, one would expect that an anesthetic performed there would be at least equally as safe as an anesthetic performed in a hospital, if not safer. However, reports of morbidity and mortality within office-based practices exist (and vary dramatically). In 1997, Morello et al. conducted a survey querying 418 accredited plastic surgeons’ offices. They had a 57% response rate and found that over a 5-year period, 400,675 office procedures were conducted: 63.2% cosmetic and 36.8% reconstructive. Several outcomes were reviewed including hemorrhage, hypertension, hypotension, wound infection, need for hospital admission, and reoperation. There was an overall complication rate of 0.24%, and seven mortalities, which were both surgery and anesthesia related. They included two myocardial infarctions (one following augmentation mammoplasty, the other 4 hours after rhinoplasty) one case of cerebral hypoxia during abdominoplasty, one tension pneumothorax during breast augmentation, one cardiac arrest during carpal tunnel surgery, one stroke 3 days following rhytidectomy and brow lift, and one unexplained death.30 These reports represent an overall mortality rate of 1 in 57,000! A report by Hoefflin et al.,31 however, found no complications after 23,000 plastic surgical procedures that occurred in a single office under general anesthesia (GA). Similarly, Sullivan and Tattini retrospectively reviewed the results in an office performing over 5,000 surgical procedures by five independent plastic surgeons. The primary anesthetic technique during this time period consisted of deep sedation in conjunction with local anesthesia or regional block, and was performed by an anesthesiologist supervising a certified registered nurse anesthetist (CRNA). No mortalities occurred over the 5-year period.32 Bitar et al. retrospectively studied adverse outcomes in 3,615 consecutive patients undergoing 4,778 plastic surgery procedures in offices between 1995 and 2000. The anesthetics were MAC with midazolam, propofol, and an opioid, and no deaths were reported. Dyspnea occurred in 0.05% of patients, nausea and vomiting 0.2%, and there was a 0.05% rate of hospital admissions.33 When analyzing these outcomes, one must appreciate that, since the mortality rate from anesthesia is so low, an extremely large cohort group would be necessary to provide real data regarding the relative risk of an office-based anesthetic. Recent data even suggest a 10-fold increased risk of morbidity and mortality associated with an office-based anesthetic when compared to one performed in a free-standing ASC.24

Other studies also reveal a significant risk associated with an office-based procedure. Rao et al. reported that according to closed malpractice claims in Florida, 830 deaths and 4,000 injuries were associated with OBA between 1990 and 1999. These claims accounted for 30% of all malpractice claims in that state.34 In a hospital operating room, the risks of an anesthetic are usually primarily related to the underlying medical condition of the patient, whereas in an office they may be increased risks secondary to factors such as inadequate standards and safeguards. More recent data from Florida have shown that office-based morbidity and mortality are usually the results of inadequate perioperative patient monitoring, over sedation and thromboembolitic events.23,25,35 The challenge of acquiring accurate morbidity and mortality data for OBA is complicated by the fact that many offices are not required to report adverse events. In addition, although an anesthesiologist may not even be administering the anesthetic in an office, many complications may still be reported as anesthetic related.

Traditional credentialing procedures, such as board certification and the granting or renewing of hospital privileges based on competency and proof of continuing medical education, may not be required or enforced in an office. Within and among offices, providers of anesthesia may also have varying degrees of both education and expertise. The provider may be an anesthesiologist, a nurse anesthetist, a dental anesthetist, or a surgeon with little or no training in anesthesia. Furthermore, safety within an anesthetizing location also depends on the perioperative patient-monitoring capabilities. Although hospital patients are mandated by the accrediting organizations to have defined standards of
care for monitoring in the operating rooms and postanesthesia care units (PACUs), these may be lacking in an inadequately prepared and nonaccredited surgical offices.33 There have been patients’ injuries reported during office-based procedures resulting from the use of obsolete and/or malfunctioning anesthesia machines, as well as from alarms that have not been serviced and/or are not functioning properly.4 The ASA created guidelines for defining obsolete anesthesia machines, which prohibit the use of any anesthesia machine that lacks essential safety features (e.g., oxygen ratio device, oxygen pressure failure alarm), has the presence of unacceptable features (e.g., copper kettles, or vaporizers with rotary concentration dials that increase vapor concentration when the dial is turned clockwise), or for which routine maintenance is no longer possible.36

A review of ASA Closed Claims Project data, which incorporates information from the 35 liability insurers that indemnify approximately 50% of the practicing anesthesiologists in the United States, reveals safety concerns in office-based practices are more than theoretical.24,37 As of 2001, there were 753 (13.7%) claims for ambulatory procedures and 14 (0.26%) for office-based ones. This small number of claims most likely due to the 3- to 5-year time lag in reporting to the database.29 ASA physical status 1 or 2 females who had undergone elective surgery under GA make up the majority of claims filed. This statistic parallels the profiles of trends seen in operating rooms and free-standing ASCs. The injuries that occur in offices tend to be of greater severity than those that occur in ASCs. Twenty-one percent of the reported injuries sustained in offices were temporary and nondisabling in nature and 64% were permanent or led to death, while 62% of the injuries sustained in ASCs were temporary and nondisabling and only 21% were permanent or led to death.29 A study by Coté et al.38,39 concluded that the causes for injuries in an office ranged from human error to machine and equipment malfunction (Table 31-2).

The Closed Claims Project database reveals that injuries during office-based procedures occur throughout the perioperative period, and are multifactorial in etiology. The majority, 64%, occurred intraoperatively, while 14% occurred in the PACU and 21% after discharge.29 Half of these adverse events were respiratory in nature and included airway obstruction, bronchospasm, inadequate oxygenation and ventilation, and unrecognized esophageal intubation. The second most common group of events were considered to be drug related, occurring 25% of the time. These included incorrect agent or dosage, allergy and malignant hyperthermia (MH). Cardiovascular injuries and equipment-related injuries each occurred in 8% of incidents.29








Table 31-2. Causes of Injury in the Office-based practice. Data from coté Et Al.38,39






  1. Inadequate resuscitation equipment
  2. Inadequate monitoring

    1. Most commonly no pulse-oximetry

  3. Inadequate preoperative or postoperative evaluation
  4. Human error

    1. Slow recognition of an event
    2. Slow response to an event
    3. Lack of experience
    4. Drug over-dosage

An important point to consider when looking at adverse events is whether or not they were preventable. Again, according to the information in the Closed Claims Project database, only 13% of the events that occurred in ASCs were considered preventable, whereas 46% of the office-based ones were deemed so. Furthermore, all of the adverse respiratory events that occurred in the PACUs of offices would have been prevented, had pulse oximetry and capnography been used. Care was considered to be substandard in 50% of OBA claims and in 34% of ASC ones. In 2001, Claims originating from an office-based procedure resulted in a monetary award 92% of the time, with a median payment of $200,000 (ranging between $10,000 and $2,000,000), whereas claims originating from ASC-based procedures were compensated only 59% of the time with a median payout of $85,000 (ranging between $34 and $14,700,000).29

Ensuring office-based practice safety is critical. After several highly publicized office liposuction injuries and deaths in August 2000, the State of Florida attempted to address this problem by placing a 90-day moratorium on all office-based procedures that utilized anesthetic depths greater than conscious sedation. During that time a safety panel comprising of surgeons, anesthesiologists, and other health-care professionals was formed and charged with the task of developing recommendations to improve the safety record of office-based procedures. The panel’s recommendations focused on factors including patient selection, preoperative evaluation and testing, procedures to be excluded, surgeon qualification and facility standards.19,40 Other major organizations that have played a leading role in developing standards for the office-based practitioner include the ASA, the ASPS, the American Association of Nurse Anesthetists (AANA), and the American Medical Association (AMA).27,40,41,42


Patient Selection

Before presenting for an office-based procedure, the patient’s medical condition should be optimally managed.43 He or she should have a preoperative history and physical examination documented within 30 days prior to the procedure, and all pertinent laboratory tests as well as any medically indicated specialist consultation(s) must be readily available. Consent for the procedure and the anesthetic must also be in the chart. The anesthesiologist should have access to all of this information preoperatively and, when possible, contact the patient prior to the scheduled procedure. If a patient is an ASA physical status 1 or 2, the surgeon’s office should arrange the surgery as per office protocol. However, if a patient has significant comorbid conditions, a preoperative anesthesiology consultation should be obtained before scheduling the patient for surgery.

Patient selection remains a controversial topic among practicing office-based anesthesiologists because little morbidity and mortality data exist to support the inclusion or exclusion of specific populations. A study by Meridy in 198244 concluded that patients should not be excluded from undergoing ambulatory procedures based solely on their age, the type of procedure, or the duration of the planned procedure. Similar data are yet to exist regarding office-based practices; however, some recommendations have been made. The ASPS has acknowledged that the ideal patient for an office-based procedure has an ASA physical status of 1 or 2. They recommended that ASA physical status 3 patients undergo an office-based procedure only after an anesthesia consultation and only have an office-based procedure performed under local anesthesia without sedation. The ASA also has developed recommendations regarding patient selection.45 It is
important to realize that the office is often remote and the anesthesiologist may be unable to get assistance should it be required. Thus, groups of patients in whom anticipated anesthetic problems may develop should be avoided (Table 31-3). Individual anesthesiologists should therefore consider excluding certain patients with significant comorbid conditions in order to avoid unanticipated problems.








Table 31-3. Poor Candidates for Office-Based Procedures






  1. Poorly controlled diabetes
  2. History of substance abuse
  3. Seizure disorder
  4. Malignant hyperthermia susceptibility
  5. Potential difficult airway

    1. Morbid obesity
    2. Obstructive sleep-apnea syndrome

  6. NPO less than 8 h
  7. No escort
  8. Previous adverse outcomes from anesthesia
  9. Significant drug allergies
  10. Aspiration risk

Morbidly obese patients and those with obstructive sleep apnea syndrome (OSAS) present unique and increasingly frequent challenges to the office-based practitioner.46 Indeed, they are usually the same population, with estimates of 60% to 90% of all obstructive sleep apnea patients being obese (body mass index greater than or equal to 30 kg/m2).47,48 Confounding this problem is that the majority of the patients with OSAS have yet to be formally diagnosed.49,50 These patients are likely to cause major anesthetic problems throughout the perioperative period.51 There may be failure to intubate, or ventilate, they may have respiratory distress soon after extubation or suffer from respiratory arrest with preoperative sedation or postoperative analgesia.49 These patients tend to be exquisitely sensitive to the respiratory depressant effects of even small dosages of sedation or analgesics.51 Furthermore, respiratory depression may not be reversible with pharmacologic antagonism.52 One of the first steps in the ASA algorithm for management of the difficult airway is to call for help. In an office, this is usually not possible. It has been recommended that a postoperative observational unit with close monitoring of oxygen saturation or an intensive care unit setting be used for monitoring the OSAS patient postoperatively.53 It may, thus, be prudent to avoid performing general anesthetics on patients with OSAS in all outpatient setting especially locations as remote as an office-based practice.

Pulmonary embolism is a significant cause of perioperative morbidity and mortality from an office-based surgical procedure.54,55 Reinisch found that 0.39% (37/9,493) of patients who underwent rhytidectomy developed a deep vein thrombosis (DVT). Of these, 40.5% (15/37) went on to form a pulmonary embolism. Although GA had only accounted for only 43% of the anesthetic techniques used for the procedure, 83.7% of the embolic events were associated with the patient having undergone a general anesthetic.56 Risk factors for the development of DVT appear in Table 31-4.57 The ASPS recommends that patients be stratified according to risk and the prophylactic treatment be directed by risk (Table 31-5).








Table 31-4. Risk Factors for the Development of Deep Vein Thrombosis (DVT)






  • Age greater than 40
  • Anti-thrombin III deficiency
  • Central nervous system disease
  • Family history of DVT
  • Heart failure
  • History of a DVT
  • Hypercoagulable states
  • Lupus anticoagulant
  • Malignancy
  • Obesity
  • Oral contraceptive use
  • Polycythemia
  • Previous miscarriage
  • Radiation therapy for pelvic neoplasms
  • Severe infection
  • Trauma
  • Venous insufficiency

As more subspecialists begin to perform office-based procedures, older and sicker patients will present. The anesthesiologist must be the patient’s advocate in the matter of safety. This advocacy can only result from a true understanding of how to adequately select appropriate patients for this unique surgical venue.








Table 31-5. Recommended Treatment for Prevention of Deep Vein Thrombosis in Patients, Stratified By Risk56,57




















Cohort Treatment
Low Risk


  • No risk factors
  • Uncomplicated surgery
  • Short duration


  • Comfortable position
  • Knees flexed at 5 degrees
  • Avoid constriction and external pressure
Moderate Risk


  • Age >40 with no other risks
  • Procedure >30 min
  • Oral contraceptive use


  • Proper positioning
  • Intermittent pneumatic compression of calf or ankle (prior to sedation and continued until patient is awake and moving)
  • Frequent alterations of the OR table
High Risk


  • Age >40 with concomitant risk factors
  • Procedure >30 min


  • Treatment as per patients with moderate risk
  • Preoperative hematology consultation with consideration of perioperative antithrombotic therapy



Surgeon Selection

The relationship between the surgeon and the anesthesiologist must be one of mutual trust and understanding. Since the surgeon performing the procedure may also own the office, he or she must not put pressure on the anesthesiologist to perform an anesthetic if the anesthesiologist believes that the patient or procedure is not appropriate.

The surgeon must have a valid medical license, registration and Drug Enforcement Administration (DEA) certificate. He or she should be either board eligible or board certified by a recognized member of the American Board of Medical Specialties, and either have privileges to perform the proposed procedure in a local hospital, or have training and documented competency comparable to a practitioner who does have such privileges in a hospital. Although this requirement may sound intuitive, there have been cases reported of surgeons performing procedures for which they have little or no training.11 In addition, the surgeon must have adequate liability insurance, at least equal to that carried by the anesthesiologist. If a lawsuit should arise and the surgeon is inadequately insured, the anesthesiologist may be held financially responsible, and become the “deep pocket.” Similarly, the facility itself should have adequate liability insurance.

In addition, there should be a system in place for monitoring continuing medical education as well as peer review and performance improvement, for the surgeon/proceduralist, anesthesiologist, and nursing staff. This is often not the case in an office-based practice.11 If an anesthesia group provides care at more than one office, an overall peer review for the practice may be used; it need not be specific to each individual office site. Solo anesthesia practitioners should not be exempt from this process. Anesthesiologists should only align themselves with the offices which have ongoing processes, or help to organize one. The peer review committee should include surgeons, anesthesiologists, and nursing staff. It should meet regularly and maintain a written record of minutes and recommendations. Similarly, continuing medical education should also be documented and at a minimum should be sufficient to meet relicensing requirements.

When formulating a quality assurance program, there should be random chart reviews as well as key sentinel events that trigger a case review (Table 31-6). It is imperative that this review be an open forum to ensure continued quality improvement of care, and not be biased or hindered by fear of litigation. Legal counsel should be sought to determine whether information disclosed at these meetings is discoverable in a court of law, should a malpractice claim arise.


Office Selection and Requirements

The anesthesiologist should function as a zealous patient advocate in assuring that an anesthetic only be performed in a safe anesthetizing location. The office needs to be appropriately equipped, stocked, and maintained to perform a general anesthetic (GA) (Table 31-7). All supplies must be age and size appropriate for the patient population. If an anesthesia machine or ventilator is present, it must be regularly serviced and calibrated. If potent inhaled volatile agents or N2O are used, there must be a functioning waste gas scavenging system. This system may be exhausted via a window or roof vent. However, the exhaust must not be vented back into the office or into any other inhabited space and
be in accordance with Occupational Safety and Health Administration (OSHA) standards. There are also portable scavenging systems available in the market that can be safely used. Air testing should be done on a regular basis. In an office without an exhaust system, total intravenous anesthesia (TIVA) techniques should be employed.

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Jun 29, 2016 | Posted by in ANESTHESIA | Comments Off on Office-Based Anesthesia

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