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Ambulatory surgery. . . how far can we go?
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AMBULATORY SURGERY ... HOW FAR CAN WE GO? James E. Davis, MD
It was written in 1986 "that the growth of ambulatory surgery will increase phenomenally in the years ahead .... growth in the foreseeable future appears almost unlimited."6 This optimistic prediction was based on three interrelated factors
1. Ambulatory surgery was no longer just a promising concept but was received totally as a superior method of providing surgical care of an intermediate magnitude. The safety of this level of care was well accepted by surgeons, the medical profession, the public, and patients. It was clearly demonstrable that ambulatory surgery was cost effective and provided greater convenience without increased risks. 2. The rapidly developing and extensive changes in health care portended well for this type of health care delivery. Constant technologic advances opened new areas in every surgical subspecialty for outpatient use, and the reimbursement regulations of both government and private carriers sought to strictly limit hospital admission. 3. Patients domiciled outside their own home (e.g. students, patients, military personnel, detainees, prisoners) were recognized as being ideal candidates for outpatient care. Patients in nursing homes, extended-care facilities, educational institutions, the military, and even penal institutions were found to be suitable for ambulatory surgery. In common, all of these varied individuals have a home-base where adequate supportive care is provided. From The University of North Carolina and Duke University, Durham, North Carolina MEDICAL CLINICS OF NORTH AMERICA VOLUME 77· NUMBER 2· MARCH 1993
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The intervening 7 years have proved this optimistic prediction to be understated. Today, the number of hospitals and freestanding units providing ambulatory surgery, the number of patients undergoing such surgery, and the percentage of surgical patients choosing the ambulatory route are all constantly increasing. The number of surgical procedures now being employed in the ambulatory setting for the first time is also impressive and appears to be open-ended. As the growth in ambulatory surgery has continued, a constant shift in the site in which this care is delivered has occurred. A clear majority of such operations is still done in the hospital setting; however, each year more cases are consistently shifted from the hospital outpatient department to surgery centers and physicians' offices. In 1988 more than 78% of outpatient surgery was done in the hospital setting; by 1992 this had fallen to 65%. Concomitantly during these same years of 1988 to 1992 the percentage of cases done in surgical centers has risen from 14% to 22%; the percentage of cases performed in physicians' offices has increased from 7% to 13% (Table 1). It is also impressive that in the years shown in Table 1 (1988 to 1992 projected) the total number of outpatient surgical cases performed has risen from almost 12 million per year to almost 18 million per year. Today, the appropriate questions are not, "Will ambulatory surgery continue to grow?" or "How rapidly will ambulatory surgery grow over the next few years?" Rather, the appropriate question today is, "How far can we go in ambulatory surgery?" To better approach an answer to this question we will consider the four forces that drive this continued expansion and greater use, namely: 1. Improvement in the construction and operation of ambulatory surgical facilities 2. New surgical techniques applicable to ambulatory surgery 3. Improved anesthetic agents and practices that make ambulatory surgery more feasible and safe 4. Regulations influencing ambulatory surgery
IMPROVED AND MORE EFFICIENTLY OPERATED FACILITIES
The emergence of 23-hour recovery units for ambulatory surgical patients is impacting on both hospitals and freestanding ambulatory surgical units. Such "recovery" units are appearing as an extension of a freestanding ambulatory unit, as an addition to the hospital near its emergency suite or its ambulatory surgical suite, or as a designated portion of an inpatient medical-surgical unit where central location is believed to be an advantage. Medicare regulations originally limited such units to 23 hours because that was considered an observation time and anything longer was converted to an inpatient stay. Currently the
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AMBULATORY SURGERY. .. HOW FAR CAN WE GO?
Table 1. OUTPATIENT SURGICAL PROCEDURES BY DELIVERY SITE, 1988-1992
Hospital outpatient Surgery centers Physician office based Total outpatient surgery
1988
1990
1992'
9300 (78.5%) 1702 (14.4%) 848 (7.1%) 11,850
10,200 (72.1%) 2313 (16.3%) 1637 (11.6%) 14,150
11,500 (65.0%) 3900 (22.0%) 2300 (13.0%) 17,700
'Projections: Figures shown are in thousands. Courtesy of SMG Marketing Group Inc.
maximum time allowed for Medicare reimbursement at most facilities under state and local regulations is 23 hours and 59 minutes. Patients who need to stay longer must be admitted as hospital inpatients. Where such units have already been established, satisfaction and high praise for this concept have been almost universal. Those experienced with this type of care emphasize that just as ambulatory surgery has proved to be an identified layer of surgical care best provided without hospital admission, retaining certain ambulatory patients for up to 23 hours identifies still another layer of care between minimal stay and hospital admission. They are convinced that society is well served by having both levels of "ambulatory care" identified and permitted. They emphasize that patients, physicians, and staff are much more comfortable with retaining some patients this additional time as it allows for more patient education and holistic care and at the same time avoids the impression of "trying to get patients in and out as quickly as possible." Payers, recognizing that this avoids more expensive inpatient charges, are also pleased. As the work load in ambulatory units, wherever located, continues to grow because of the ever enlarging number of procedures that can be done in the ambulatory setting, many centers are extending their work hours to evenings and weekends. This is believed to benefit particularly those patients who are reluctant to miss work. In California, the legislature has authorized a demonstration project that permits 13 existing centers throughout the state to retain patients in a recovery care center for up to 72 hours. 4 This type of care is designed for otherwise healthy patients who have had elective surgery and require postoperative supervision but not all the services of an acute-care hospital. These recovery care centers treat patients in wellstaffed, hospital-like accommodations for 25% to 50% of the cost of hospital inpatient care. Understandably, both the freestanding ambulatory units and the hospitals are anxious to enter this field, and the demonstration project includes units at both types of sites. Early information from this study indicates that the charges for recovery center care range from $300 to $560 per day, as compared with the average hospital inpatient charge of $1350 per day. Ambulatory surgery has not escaped the trend to mobile health care facilities. Mobile operating rooms are now available in California, 11
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and available medical facilities include MRI, CT, mammography, and lithotripsy. Mobile operating rooms have been used in the former Soviet Union, Canada, and Israel, and they are said to be similar to the ones used by the US Armed Forces in the Persian Gulf area, except that the military mobile units are not on wheels and cannot be moved as quickly. The mobile operating room measures 46 x 8 ft and is of a semitrailer-type construction. The features include an operating room, preoperative patient preparation and holding area, postanesthesia recovery area, dressing facility with lockers and laboratory, and a hydraulic entrance lift. These units are designed to supplement hospital operating rooms, especially in smaller hospitals. Other proposed uses for the unit are as an outpatient surgical facility at medical office buildings, geriatric centers, corporate medical facilities, or even in conjunction with recovery care units. It is expected that such units will be attractive to and used especially by people in rural areas who do not normally have surgical access but can now have it brought directly to them.
NEW SURGICAL TECHNIQUES
The emergence of laparoscopic surgery by general surgeons and the extension of use of the laparoscope by gynecologists are a bonanza to ambulatory surgery. These procedures, sometimes referred to as "video surgery," which dramatically shorten the need for postoperative observation and care, have significantly reduced hospital stay and are rapidly moving into the realm of same-day surgery. This advance, coupled with the legalization in many states of a stay up to 23 hours in an ambulatory surgical unit, opens up the potential for wholesale shifting of operative procedures from the hospital to the ambulatory setting. This trend is now moving rapidly. Evidence indicates that the change, both in the increased number of procedures found suitable for ambulatory care and in the shift in the site in which care is delivered, is proceeding with greater comfort to the patient, less lost work-time, increased dollar savings, and no loss of safety.
Laparoscopic Cholecystectomy
As many as 20 million Americans have gallstones; about 500,000 of them undergo surgical removal of the gallbladder each year. Cholecystectomy remains the traditional treatment for symptomatic gallstone disease, but the site and manner in which cholecystectomy is performed continues to change. Conventional "open" operations involve general anesthesia, a large abdominal incision, 3 to 5 days of hospitalization, and 3 to 4 weeks of recovery.
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In contrast, laparoscopic cholecystectomy, a procedure in which the gallbladder is removed with a laparoscope and miniature instruments requiring only small incisions, offers patients less pain, shorter period of inactivity, and a recovery time of days rather than weeks. Generally, patients after laparoscopic cholecystectomy can be discharged when they are free of significant pain and nausea, can take food by mouth, and can maintain themselves at home. Whether this period of postoperative care and observation is done in a hospital or in an ambulatory surgical unit (with 4 to 23 hours of care) appears not to make a difference. Such patients normally return to work the following week. The safety of laparoscopic cholecystectomy was evaluated in a prospective cooperative study of 1518 patients, almost equally divided between those in academic hospitals and those in private hospitals. 18 In 4.7% of cases, the operation was converted to conventional open cholecystectomy, the most common reason for the change being the inability to identify the anatomy of the gallbladder as a result of inflammation. Only a small amount (5.1 %) of the patients had complications, quite comparable to the rates reported for conventional cholecystectomy. Overall, the most common complication was superficial infection at the site of insertion of the umbilical trocar. Only 0.5% of the patients suffered injuries to the common bile duct or the hepatic duct. The instance of bile-duct injury in the first 13 patients operated on by each surgeon was 2.2%, as compared with 0.1 % for subsequent patients. The existence of a "learning curve" as individual surgeons gain experience is indicated in much of the literature, suggesting that after 13 to 15 procedures the complications occur less often. The mean hospital stay for the entire group was 1.2 days (range, 6 hours to 30 days). The cost-effectiveness of laparoscopic cholecystectomy remains in doubt. Some studies7 indicate that the laparoscopic approach is less expensive, owing primarily to shorter hospitalization. Almost all studies suggest that the operating room time required for laparoscopic surgery is greater than for open cholecystectomy, owing in part to the training of established surgeons in the procedure as well as resident surgeons. In other reports, the cost for the laparoscopic approach is higher than for open cholecystectomy despite shorter hospitalization. This was attributed both to the higher operating room expenses, including longer duration of operation, and also the use of costly equipment needed for the procedure, such as disposable trocars and clip appliers. 17 It is generally believed that when the total costs of laparoscopic and open cholecystectomies are compared, including less financial loss by the patient owing to shorter absence from work, the economic advantage of the laparoscopic approach is apparent. Laparoscopic cholecystectomy is a major surgical procedure, and postoperative care at home is important. This can be provided by reliable family members or a home health nurse. 16 Older patients are more likely to require overnight stay to recover from the prolonged
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effects of anesthesia, especially if concurrent disease, urinary retention, or slow return of intestinal function is present. It appears safe to predict that in the near future 80% to 90% of cholecystectomies will be done with only a postoperative stay of from 4 to 23 hours. Consequently, this procedure will certainly become a major contributor to the increased work load of those providing ambulatory surgery. General surgeons, having learned laparoscopic surgery to perform laparoscopic cholecystectomies, are rapidly extending this skill throughout the abdomen. Laparoscopic hernia repairs, appendectomies, and colectomies are among the procedures now being done. Gynecologists, many with years of experience as laparoscopists, are rapidly extending their skill into pelvic surgery. These types of cases are also amenable to being performed in the ambulatory setting and will add to the large numbers of surgical procedures being shifted from the hospital to the ambulatory site. Laparoscopic hysterectomies are being done with frequency. Additionally, the laparoscope is being used for intra-abdominal and pelvic endometriosis, ectopic pregnancies, and resection of benign tumors, especially dermoid cysts, hydrosalpinges, and others. Many patients with menometrorrhagia who formerly would have been subjected to a hysterectomy are now being treated as ambulatory surgical patients, receiving the procedure of endometrial ablation. The ablation procedure is done using a YAG laser via an optic fiber within the uterine cavity. It has been estimated that between 30% and 40% of the 750,000 patients having a hysterectomy in the United States each year may be candidates for this procedure. Every subspecialty of surgery has types of cases amenable to correction in the ambulatory setting. According to Medicare data, the number of left cardiac catheterizations done in outpatient departments increased from 84 to 7180 and right/left cardiac catherizations from 20 to more than 5000 over the course of 2 years. Neurosurgeons are reporting successfully performed lumbar microdiscectomy in patients who have radicular leg pain refractive to conservative measures and objective focal root deficit with an abnormal CT scan or MRI corroborating the clinical diagnosis. The discharge criteria for these patients is the same for all other ambulatory patients. They are usually ready to leave the unit 3 hours after surgery and should be taken home by a responsible adult in a standard vehicle. 3 Urologists are now using the ambulatory setting for transcystoscopic urethroplasty. This applies the experiences of cardiologists in clearing coronary arteries by balloon angioplasty. In urethroplasty, a small balloon is passed into the prostate through the urinary tract, inflated for approximately 10 minutes, and then removed. A Foley catheter is left in place for 48 to 72 hours. 9 Restoration of previously divided vas deferens by microvasovasostomy can be done in the ambulatory setting. 12. 13 Many plastic and reconstruction surgeons perform liposuction in the same-day surgery environment. In such units there appears to be
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less risk of infection and better quality control than is provided in the surgeon's office. 14
IMPROVED ANESTHETIC AGENTS AND PRACTICES
Several recent advances in anesthesia have improved ambulatory surgery, making it both safer and more acceptable to patients.
Propofol
Propofol (Diprivan) has only recently been approved by the US Food and Drug Administration. It was first approved for use in England in 1986 and has since become widely used in outpatient surgery throughout Europe, with more than 7 million patients having received propofol since 1986. Propofol is a sedative-hypnotic agent, the first of a new class of anesthetic agents called alkylphenols. It is the first intravenous anesthetic agent that can be used for both induction and maintenance of general anesthesia. In Europe it has now replaced thiopental in up to half of all outpatient surgery cases. Although propofol is two to three times more expensive than thiopentat researchers believe that it is cost effective because it allows for an earlier discharge. 19 Although propofol is suitable for many procedures in both the inpatient and outpatient settings, several studies have addressed specifically its suitability in the latter setting. 5, 10 The drug offers improved speed and quality of recovery and also has significantly fewer postanesthetic side effects. Its superior recovery profile has resulted in earlier discharge of patients from the postanesthesia recovery room, allowing for more cost-efficient use of that area and its nursing staff. Propofol offers an alternative to barbiturates for maintenance of sedation during local or regional anesthesia in patients who have had a history of allergic reactions to those compounds. It is also useful in patients with acute intermittent porphyria and hereditary coproporphyria. Propofol has been compared to thiopentat one of the most widely used intravenous anesthetics in ambulatory surgery, and it is found to be approximately twice as potent as thiopental when used for induction of anesthesia. In contrast to thiopentat propofol is stable in solution and has a long shelf-life. Propofol does, however, have the disadvantage of producing a burning sensation when injected into a small vein of the hand or forearm, unlike thiopental. Both drugs produce rapid onset of sedation and hypnotic effects; both produce dose-related cardiorespiratory depression. Studies performed in comparing the two agents have demonstrated that propofol-treated patients spend a shorter time in recovery room, recover psychomotor activity more
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rapidly, have less nausea and vomiting, and return to productive activity earlier. 5, 10, 19, 20 Propofol should be used with caution in elderly, debilitated, and hypovolemic patients and those rated American Society of Anesthesiologists Class III or IV. Propofol is not recommended for use in pediatric patients, nursing mothers, or patients with increased intracranial pressure or impaired cerebral circulation. It is also not recommended in obstetrics, including cesarean-section deliveries. Drug interactions appear not to be a problem. Propofol has been used safely in conjunction with a variety of agents commonly used in anesthesia such as premedicants, muscle relaxants, analgesics, and inhalational and regional anesthetic agents. To date, no pharmacological incompatibilities with propofol have been reported.
Flumazenil
Another advance in ambulatory surgery anesthesia is with the use of flumazenil, which awakens patients from anesthesia easily and quickly. Flumazenil reverses the drowsiness that occurs after the use of midazolam, diazepam, and similar drugs commonly used in ambulatory surgery. Although midazolam has been used widely, patients have complained that it causes excessive drowsiness following surgery. This drowsiness contributes to discomfort during recovery and often substantially prolongs the discharge time. Flumazenil reverses the drowsiness, and the amount of reversal can be controlled so that patients recover feeling awake but calm.
Clear Liquids Before Surgery
Traditionally, surgeons have instructed patients to avoid food and liquid after midnight on the day before surgery. This is intended to reduce the risks of vomiting, regurgitation, and aspiration pneumonia. Ambulatory surgical patients sometimes do not comply with instructions for fasting, however. This traditional policy is also questionable because it does not recognize factors such as the scheduled time for surgery, the time the patient went to bed, and rates at which the stomach empties solids and liquids. Recent studies have focused on liquids such as clear fruit juice, carbonated beverages, tea, coffee and water. Liquids with suspension, such as juice with pulp, and liquids that may form solids in the stomach, such as milk, are excluded. Solid food and milk products delay the emptying time of gastric fluids from the stomach. It appears that 2 to 3 hours before surgery is a good cutoff point for clear liquids. There is a body of literature now that first studied adults and documents that clear liquids up to 2 hours before surgery does not affect the gastric fluid volume. 15
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REGULATIONS
Ambulatory surgery is also subject to governmental regulations as are the other components of the health care system. The focus of concern in ambulatory surgery has been the ownership of ambulatory surgical facilities. These have been either privately owned by physicians or hospital-supported. With the former group the issue becomes the propriety of physicians referring patients to facilities in which they have financial interest. It has been shown that ambulatory surgical centers save hundreds of millions of medical dollars per year. The Department of Health and Human Services Office of Inspector General has reported that for each cataract operation, Medicare pays 45% more to hospitals than it does to an ambulatory surgical center. These physician-owned centers have operated successfully without abuse and have saved considerable money for the Medicare and Medicaid programs. The Office of Inspector General has recommended that ambulatory surgical centers that are physician-owned not be reviewed as a conflict of interest. Consequently, government pressure has increased concerning physician referral of patients to facilities in which they have a financial interest, such as clinical laboratories and imaging centers, but such has not been true of ambulatory surgical centers. In early 1992 the Health Care Financing Administration! added nearly 900 procedures to the list of covered ambulatory surgery procedures. This extensive list opens the door for freestanding ambulatory surgical centers to receive a facility fee for additional procedures, giving them a strong competitive edge over hospital-based outpatient surgical units. This is primarily because the new payment mechanism changes from cost-based reimbursement in hospitals to a blend of the ambulatory surgical center rate and hospital cost. Although the full impact of this will perhaps not be felt for the next year, or until the end of the hospitals' fiscal year, it is believed by many experts that the blended reimbursement is almost certain not to cover the hospital cost. Because hospitals will be receiving less reimbursement for nearly 900 procedures, it is generally believed that hospitals will be hard pressed to perform them. This change in reimbursement likely will have an impact beyond Medicare, because many state Medicaid plans and private payers also use this list for reimbursement. The new list of covered procedures in ambulatory surgical centers speaks not only of reimbursement. It speaks loudly of the government's and the public's acceptance of much more complex surgical procedures being performed in ambulatory sites. Some randomly selected procedures now approved include partial mastectomy with axillary dissection, breast reconstruction with muscle or myocutaneous flap, repair of nonunion or malunion humerus with iliac or other autograft (including taking graft), amputation of the arm or leg, embolectomy or thrombectomy, total excision of carotid tumor or gland with sacrifice or preservation of facial nerve, combined anteroposterior colporrhaphy with
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enterocele repair, exenteration of the orbit with temporalis muscle transplant, radical mastoidectomy, and many others. THE FUTURE
The 1970s and 1980s have seen consistent expansion of ambulatory surgery. This is true whether this growth is measured by the number of facilities providing ambulatory surgery, the number of patients receiving such care, the percentage of surgical patients choosing the ambulatory site, or the number of procedures chosen by surgeons and approved by third-party payers to be done on an ambulatory basis. We have seen earlier that the four forces that drive this expansion, improved and better operated facilities, new surgical techniques, improved anesthetic agents and practices, and regulations influencing ambulatory surgery, are all strong and appear to be gaining momentum. Patients, physicians, and the public have all accepted this method of delivering surgical care as being very appropriate, cost-effective, and satisfactory. Much of the evolving technology makes and will continue to make surgery easier on the patient and requiring less postoperative care and observation, making it ideal for the ambulatory setting. This is especially true of "video surgery" in which more and more abdominal and thoracic procedures are being done with small incisions, scopes, instruments, and cameras. With many ambulatory units already keeping patients for 23 hours and others very likely extending this to a 2or 3-day stay, the great majority of this huge volume of work will be shifted to the ambulatory setting. The first half of the 1990s will be remembered as a period of economic austerity and the absolute need for restraint of ever-increasing health care costs. The economic benefit of performing this magnitude of surgical cases out-of-hospital is not only apparent to all but is being demanded by business, insurors (especially those offering managed health care coverage), and government (the largest purchaser of health care), as well as individual patients. Regulations, imposed both by government and other third-party payers, will continue to force more procedures out of hospitals into ambulatory sites. Even if increasing pressure against "self-referral" should force physician-owners of ambulatory surgical centers to divest of the ownership of such units, the facilities will continue to operate and expand. When all of these factors are considered, it is quite appropriate in 1993, just as in 1986, to again predict "that the growth of ambulatory surgery will increase phenomenally in the years ahead .... growth in the foreseeable future appears almost unlimited." References 1. Abbey F: Same-Day Surg 16:29-31, 35-53, 1992 2. Battaglia Cl: FA SA Update VIII: 4-5, 1991
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3. Cares HL, Steinberg RS, Robertson ET: Ambulatory microsurgery for ruptured lumbar discs: Report of ten cases. Neurosurgery 22:523-526, 1988 4. Carr JA 1II: Recovery care concept gains ASC, hospital interest. Same-Day Surg 14:123-124, 1990 5. Cork RC, Scipione P, Vonesh MJ, et al: Propofol infusion vs thiopentaliisoflurane for outpatient anesthesia. Anesthesiology 69(suppl):3A, 1988 6. Davis JE: Major Ambulatory Surgery. Baltimore, Williams & Wilkins, 1986 7. Duncan T: New gallbladder removal technique cuts costs. Same-Day Surg 14:24-25, 1990 8. Holt BB: Procedure reduces endometrial lining, helps some patients avoid hysterectomy. Same-Day Surg 12:107-109, 1988 9. Klein L: New prostate procedure offers outpatient alternative. Same-Day Surg 13:141144, 1989 10. Kortilla K, Faure E, Apfelbaum J, et al: Recovery from propofol vs. thiopental isoflurane in patients undergoing outpatient anesthesia. Anesthesiology 69(suppl):3A, 1988 11. Levine B: Mobile overrating rooms offered as outpatient-surgery alternative. SameDay Surg 15:43-44, 1991 12. Mamakos MS: Ambulatory microvasovasostomy program achieving 80% fertility rate. Same-Day Surg 12:153-154, 1988 13. Mamakos MS: Surgeon does vas reversals as same-day procedure. Same-Day Surg 13:134-136, 1989 14. Newman J, Rose FA, Cantrell RW: Liposuction provides SOS facilities with safe new procedure. Same-Day Surg 11:145-149, 1987 15. Schreiner MS, Triebwasser A, Keon TP: Ingestions of liquids compared with preoperative fasting in pediatric outpatients. Anesthesiology 72:593-597, 1990 16. Schultz LS: Caution urged with outpatient laparoscopic cholecystectomy. Same-Day Surg 15:13-15, 1991 17. Stoker ME, Vose L O'Mara P, et al: Laparoscopic cholecystectomy: A clinical and financial analysis of 280 operations. Arch Surg 127:589-595, 1992 18. The Southern Surgeons Club: A prospective analysis of 1,518 laparoscopic cholecystectomies. NEJM 324:1073-1078, 1991 19. White F: Propofol: Pharmacokinetics and pharmacodynamics. Sem Anesthes 7(suppl 1): 1988 20. Yung-Fong S, Freniere S, Tillette T, et al: Comparison of propofol and thiopental anesthesia in outpatient surgery: Speed of recovery. Anesthesiology 69(suppl):3A, 1988
Address reprint requests to James E. Davis, MD 2609 North Duke Street Durham, NC 27704
0025-7125/93 $0.00 + .20
AMBULATORY SURGERY ... HOW FAR CAN WE GO? James E. Davis, MD
It was written in 1986 "that the growth of ambulatory surgery will increase phenomenally in the years ahead .... growth in the foreseeable future appears almost unlimited."6 This optimistic prediction was based on three interrelated factors
1. Ambulatory surgery was no longer just a promising concept but was received totally as a superior method of providing surgical care of an intermediate magnitude. The safety of this level of care was well accepted by surgeons, the medical profession, the public, and patients. It was clearly demonstrable that ambulatory surgery was cost effective and provided greater convenience without increased risks. 2. The rapidly developing and extensive changes in health care portended well for this type of health care delivery. Constant technologic advances opened new areas in every surgical subspecialty for outpatient use, and the reimbursement regulations of both government and private carriers sought to strictly limit hospital admission. 3. Patients domiciled outside their own home (e.g. students, patients, military personnel, detainees, prisoners) were recognized as being ideal candidates for outpatient care. Patients in nursing homes, extended-care facilities, educational institutions, the military, and even penal institutions were found to be suitable for ambulatory surgery. In common, all of these varied individuals have a home-base where adequate supportive care is provided. From The University of North Carolina and Duke University, Durham, North Carolina MEDICAL CLINICS OF NORTH AMERICA VOLUME 77· NUMBER 2· MARCH 1993
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The intervening 7 years have proved this optimistic prediction to be understated. Today, the number of hospitals and freestanding units providing ambulatory surgery, the number of patients undergoing such surgery, and the percentage of surgical patients choosing the ambulatory route are all constantly increasing. The number of surgical procedures now being employed in the ambulatory setting for the first time is also impressive and appears to be open-ended. As the growth in ambulatory surgery has continued, a constant shift in the site in which this care is delivered has occurred. A clear majority of such operations is still done in the hospital setting; however, each year more cases are consistently shifted from the hospital outpatient department to surgery centers and physicians' offices. In 1988 more than 78% of outpatient surgery was done in the hospital setting; by 1992 this had fallen to 65%. Concomitantly during these same years of 1988 to 1992 the percentage of cases done in surgical centers has risen from 14% to 22%; the percentage of cases performed in physicians' offices has increased from 7% to 13% (Table 1). It is also impressive that in the years shown in Table 1 (1988 to 1992 projected) the total number of outpatient surgical cases performed has risen from almost 12 million per year to almost 18 million per year. Today, the appropriate questions are not, "Will ambulatory surgery continue to grow?" or "How rapidly will ambulatory surgery grow over the next few years?" Rather, the appropriate question today is, "How far can we go in ambulatory surgery?" To better approach an answer to this question we will consider the four forces that drive this continued expansion and greater use, namely: 1. Improvement in the construction and operation of ambulatory surgical facilities 2. New surgical techniques applicable to ambulatory surgery 3. Improved anesthetic agents and practices that make ambulatory surgery more feasible and safe 4. Regulations influencing ambulatory surgery
IMPROVED AND MORE EFFICIENTLY OPERATED FACILITIES
The emergence of 23-hour recovery units for ambulatory surgical patients is impacting on both hospitals and freestanding ambulatory surgical units. Such "recovery" units are appearing as an extension of a freestanding ambulatory unit, as an addition to the hospital near its emergency suite or its ambulatory surgical suite, or as a designated portion of an inpatient medical-surgical unit where central location is believed to be an advantage. Medicare regulations originally limited such units to 23 hours because that was considered an observation time and anything longer was converted to an inpatient stay. Currently the
367
AMBULATORY SURGERY. .. HOW FAR CAN WE GO?
Table 1. OUTPATIENT SURGICAL PROCEDURES BY DELIVERY SITE, 1988-1992
Hospital outpatient Surgery centers Physician office based Total outpatient surgery
1988
1990
1992'
9300 (78.5%) 1702 (14.4%) 848 (7.1%) 11,850
10,200 (72.1%) 2313 (16.3%) 1637 (11.6%) 14,150
11,500 (65.0%) 3900 (22.0%) 2300 (13.0%) 17,700
'Projections: Figures shown are in thousands. Courtesy of SMG Marketing Group Inc.
maximum time allowed for Medicare reimbursement at most facilities under state and local regulations is 23 hours and 59 minutes. Patients who need to stay longer must be admitted as hospital inpatients. Where such units have already been established, satisfaction and high praise for this concept have been almost universal. Those experienced with this type of care emphasize that just as ambulatory surgery has proved to be an identified layer of surgical care best provided without hospital admission, retaining certain ambulatory patients for up to 23 hours identifies still another layer of care between minimal stay and hospital admission. They are convinced that society is well served by having both levels of "ambulatory care" identified and permitted. They emphasize that patients, physicians, and staff are much more comfortable with retaining some patients this additional time as it allows for more patient education and holistic care and at the same time avoids the impression of "trying to get patients in and out as quickly as possible." Payers, recognizing that this avoids more expensive inpatient charges, are also pleased. As the work load in ambulatory units, wherever located, continues to grow because of the ever enlarging number of procedures that can be done in the ambulatory setting, many centers are extending their work hours to evenings and weekends. This is believed to benefit particularly those patients who are reluctant to miss work. In California, the legislature has authorized a demonstration project that permits 13 existing centers throughout the state to retain patients in a recovery care center for up to 72 hours. 4 This type of care is designed for otherwise healthy patients who have had elective surgery and require postoperative supervision but not all the services of an acute-care hospital. These recovery care centers treat patients in wellstaffed, hospital-like accommodations for 25% to 50% of the cost of hospital inpatient care. Understandably, both the freestanding ambulatory units and the hospitals are anxious to enter this field, and the demonstration project includes units at both types of sites. Early information from this study indicates that the charges for recovery center care range from $300 to $560 per day, as compared with the average hospital inpatient charge of $1350 per day. Ambulatory surgery has not escaped the trend to mobile health care facilities. Mobile operating rooms are now available in California, 11
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and available medical facilities include MRI, CT, mammography, and lithotripsy. Mobile operating rooms have been used in the former Soviet Union, Canada, and Israel, and they are said to be similar to the ones used by the US Armed Forces in the Persian Gulf area, except that the military mobile units are not on wheels and cannot be moved as quickly. The mobile operating room measures 46 x 8 ft and is of a semitrailer-type construction. The features include an operating room, preoperative patient preparation and holding area, postanesthesia recovery area, dressing facility with lockers and laboratory, and a hydraulic entrance lift. These units are designed to supplement hospital operating rooms, especially in smaller hospitals. Other proposed uses for the unit are as an outpatient surgical facility at medical office buildings, geriatric centers, corporate medical facilities, or even in conjunction with recovery care units. It is expected that such units will be attractive to and used especially by people in rural areas who do not normally have surgical access but can now have it brought directly to them.
NEW SURGICAL TECHNIQUES
The emergence of laparoscopic surgery by general surgeons and the extension of use of the laparoscope by gynecologists are a bonanza to ambulatory surgery. These procedures, sometimes referred to as "video surgery," which dramatically shorten the need for postoperative observation and care, have significantly reduced hospital stay and are rapidly moving into the realm of same-day surgery. This advance, coupled with the legalization in many states of a stay up to 23 hours in an ambulatory surgical unit, opens up the potential for wholesale shifting of operative procedures from the hospital to the ambulatory setting. This trend is now moving rapidly. Evidence indicates that the change, both in the increased number of procedures found suitable for ambulatory care and in the shift in the site in which care is delivered, is proceeding with greater comfort to the patient, less lost work-time, increased dollar savings, and no loss of safety.
Laparoscopic Cholecystectomy
As many as 20 million Americans have gallstones; about 500,000 of them undergo surgical removal of the gallbladder each year. Cholecystectomy remains the traditional treatment for symptomatic gallstone disease, but the site and manner in which cholecystectomy is performed continues to change. Conventional "open" operations involve general anesthesia, a large abdominal incision, 3 to 5 days of hospitalization, and 3 to 4 weeks of recovery.
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In contrast, laparoscopic cholecystectomy, a procedure in which the gallbladder is removed with a laparoscope and miniature instruments requiring only small incisions, offers patients less pain, shorter period of inactivity, and a recovery time of days rather than weeks. Generally, patients after laparoscopic cholecystectomy can be discharged when they are free of significant pain and nausea, can take food by mouth, and can maintain themselves at home. Whether this period of postoperative care and observation is done in a hospital or in an ambulatory surgical unit (with 4 to 23 hours of care) appears not to make a difference. Such patients normally return to work the following week. The safety of laparoscopic cholecystectomy was evaluated in a prospective cooperative study of 1518 patients, almost equally divided between those in academic hospitals and those in private hospitals. 18 In 4.7% of cases, the operation was converted to conventional open cholecystectomy, the most common reason for the change being the inability to identify the anatomy of the gallbladder as a result of inflammation. Only a small amount (5.1 %) of the patients had complications, quite comparable to the rates reported for conventional cholecystectomy. Overall, the most common complication was superficial infection at the site of insertion of the umbilical trocar. Only 0.5% of the patients suffered injuries to the common bile duct or the hepatic duct. The instance of bile-duct injury in the first 13 patients operated on by each surgeon was 2.2%, as compared with 0.1 % for subsequent patients. The existence of a "learning curve" as individual surgeons gain experience is indicated in much of the literature, suggesting that after 13 to 15 procedures the complications occur less often. The mean hospital stay for the entire group was 1.2 days (range, 6 hours to 30 days). The cost-effectiveness of laparoscopic cholecystectomy remains in doubt. Some studies7 indicate that the laparoscopic approach is less expensive, owing primarily to shorter hospitalization. Almost all studies suggest that the operating room time required for laparoscopic surgery is greater than for open cholecystectomy, owing in part to the training of established surgeons in the procedure as well as resident surgeons. In other reports, the cost for the laparoscopic approach is higher than for open cholecystectomy despite shorter hospitalization. This was attributed both to the higher operating room expenses, including longer duration of operation, and also the use of costly equipment needed for the procedure, such as disposable trocars and clip appliers. 17 It is generally believed that when the total costs of laparoscopic and open cholecystectomies are compared, including less financial loss by the patient owing to shorter absence from work, the economic advantage of the laparoscopic approach is apparent. Laparoscopic cholecystectomy is a major surgical procedure, and postoperative care at home is important. This can be provided by reliable family members or a home health nurse. 16 Older patients are more likely to require overnight stay to recover from the prolonged
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effects of anesthesia, especially if concurrent disease, urinary retention, or slow return of intestinal function is present. It appears safe to predict that in the near future 80% to 90% of cholecystectomies will be done with only a postoperative stay of from 4 to 23 hours. Consequently, this procedure will certainly become a major contributor to the increased work load of those providing ambulatory surgery. General surgeons, having learned laparoscopic surgery to perform laparoscopic cholecystectomies, are rapidly extending this skill throughout the abdomen. Laparoscopic hernia repairs, appendectomies, and colectomies are among the procedures now being done. Gynecologists, many with years of experience as laparoscopists, are rapidly extending their skill into pelvic surgery. These types of cases are also amenable to being performed in the ambulatory setting and will add to the large numbers of surgical procedures being shifted from the hospital to the ambulatory site. Laparoscopic hysterectomies are being done with frequency. Additionally, the laparoscope is being used for intra-abdominal and pelvic endometriosis, ectopic pregnancies, and resection of benign tumors, especially dermoid cysts, hydrosalpinges, and others. Many patients with menometrorrhagia who formerly would have been subjected to a hysterectomy are now being treated as ambulatory surgical patients, receiving the procedure of endometrial ablation. The ablation procedure is done using a YAG laser via an optic fiber within the uterine cavity. It has been estimated that between 30% and 40% of the 750,000 patients having a hysterectomy in the United States each year may be candidates for this procedure. Every subspecialty of surgery has types of cases amenable to correction in the ambulatory setting. According to Medicare data, the number of left cardiac catheterizations done in outpatient departments increased from 84 to 7180 and right/left cardiac catherizations from 20 to more than 5000 over the course of 2 years. Neurosurgeons are reporting successfully performed lumbar microdiscectomy in patients who have radicular leg pain refractive to conservative measures and objective focal root deficit with an abnormal CT scan or MRI corroborating the clinical diagnosis. The discharge criteria for these patients is the same for all other ambulatory patients. They are usually ready to leave the unit 3 hours after surgery and should be taken home by a responsible adult in a standard vehicle. 3 Urologists are now using the ambulatory setting for transcystoscopic urethroplasty. This applies the experiences of cardiologists in clearing coronary arteries by balloon angioplasty. In urethroplasty, a small balloon is passed into the prostate through the urinary tract, inflated for approximately 10 minutes, and then removed. A Foley catheter is left in place for 48 to 72 hours. 9 Restoration of previously divided vas deferens by microvasovasostomy can be done in the ambulatory setting. 12. 13 Many plastic and reconstruction surgeons perform liposuction in the same-day surgery environment. In such units there appears to be
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less risk of infection and better quality control than is provided in the surgeon's office. 14
IMPROVED ANESTHETIC AGENTS AND PRACTICES
Several recent advances in anesthesia have improved ambulatory surgery, making it both safer and more acceptable to patients.
Propofol
Propofol (Diprivan) has only recently been approved by the US Food and Drug Administration. It was first approved for use in England in 1986 and has since become widely used in outpatient surgery throughout Europe, with more than 7 million patients having received propofol since 1986. Propofol is a sedative-hypnotic agent, the first of a new class of anesthetic agents called alkylphenols. It is the first intravenous anesthetic agent that can be used for both induction and maintenance of general anesthesia. In Europe it has now replaced thiopental in up to half of all outpatient surgery cases. Although propofol is two to three times more expensive than thiopentat researchers believe that it is cost effective because it allows for an earlier discharge. 19 Although propofol is suitable for many procedures in both the inpatient and outpatient settings, several studies have addressed specifically its suitability in the latter setting. 5, 10 The drug offers improved speed and quality of recovery and also has significantly fewer postanesthetic side effects. Its superior recovery profile has resulted in earlier discharge of patients from the postanesthesia recovery room, allowing for more cost-efficient use of that area and its nursing staff. Propofol offers an alternative to barbiturates for maintenance of sedation during local or regional anesthesia in patients who have had a history of allergic reactions to those compounds. It is also useful in patients with acute intermittent porphyria and hereditary coproporphyria. Propofol has been compared to thiopentat one of the most widely used intravenous anesthetics in ambulatory surgery, and it is found to be approximately twice as potent as thiopental when used for induction of anesthesia. In contrast to thiopentat propofol is stable in solution and has a long shelf-life. Propofol does, however, have the disadvantage of producing a burning sensation when injected into a small vein of the hand or forearm, unlike thiopental. Both drugs produce rapid onset of sedation and hypnotic effects; both produce dose-related cardiorespiratory depression. Studies performed in comparing the two agents have demonstrated that propofol-treated patients spend a shorter time in recovery room, recover psychomotor activity more
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rapidly, have less nausea and vomiting, and return to productive activity earlier. 5, 10, 19, 20 Propofol should be used with caution in elderly, debilitated, and hypovolemic patients and those rated American Society of Anesthesiologists Class III or IV. Propofol is not recommended for use in pediatric patients, nursing mothers, or patients with increased intracranial pressure or impaired cerebral circulation. It is also not recommended in obstetrics, including cesarean-section deliveries. Drug interactions appear not to be a problem. Propofol has been used safely in conjunction with a variety of agents commonly used in anesthesia such as premedicants, muscle relaxants, analgesics, and inhalational and regional anesthetic agents. To date, no pharmacological incompatibilities with propofol have been reported.
Flumazenil
Another advance in ambulatory surgery anesthesia is with the use of flumazenil, which awakens patients from anesthesia easily and quickly. Flumazenil reverses the drowsiness that occurs after the use of midazolam, diazepam, and similar drugs commonly used in ambulatory surgery. Although midazolam has been used widely, patients have complained that it causes excessive drowsiness following surgery. This drowsiness contributes to discomfort during recovery and often substantially prolongs the discharge time. Flumazenil reverses the drowsiness, and the amount of reversal can be controlled so that patients recover feeling awake but calm.
Clear Liquids Before Surgery
Traditionally, surgeons have instructed patients to avoid food and liquid after midnight on the day before surgery. This is intended to reduce the risks of vomiting, regurgitation, and aspiration pneumonia. Ambulatory surgical patients sometimes do not comply with instructions for fasting, however. This traditional policy is also questionable because it does not recognize factors such as the scheduled time for surgery, the time the patient went to bed, and rates at which the stomach empties solids and liquids. Recent studies have focused on liquids such as clear fruit juice, carbonated beverages, tea, coffee and water. Liquids with suspension, such as juice with pulp, and liquids that may form solids in the stomach, such as milk, are excluded. Solid food and milk products delay the emptying time of gastric fluids from the stomach. It appears that 2 to 3 hours before surgery is a good cutoff point for clear liquids. There is a body of literature now that first studied adults and documents that clear liquids up to 2 hours before surgery does not affect the gastric fluid volume. 15
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REGULATIONS
Ambulatory surgery is also subject to governmental regulations as are the other components of the health care system. The focus of concern in ambulatory surgery has been the ownership of ambulatory surgical facilities. These have been either privately owned by physicians or hospital-supported. With the former group the issue becomes the propriety of physicians referring patients to facilities in which they have financial interest. It has been shown that ambulatory surgical centers save hundreds of millions of medical dollars per year. The Department of Health and Human Services Office of Inspector General has reported that for each cataract operation, Medicare pays 45% more to hospitals than it does to an ambulatory surgical center. These physician-owned centers have operated successfully without abuse and have saved considerable money for the Medicare and Medicaid programs. The Office of Inspector General has recommended that ambulatory surgical centers that are physician-owned not be reviewed as a conflict of interest. Consequently, government pressure has increased concerning physician referral of patients to facilities in which they have a financial interest, such as clinical laboratories and imaging centers, but such has not been true of ambulatory surgical centers. In early 1992 the Health Care Financing Administration! added nearly 900 procedures to the list of covered ambulatory surgery procedures. This extensive list opens the door for freestanding ambulatory surgical centers to receive a facility fee for additional procedures, giving them a strong competitive edge over hospital-based outpatient surgical units. This is primarily because the new payment mechanism changes from cost-based reimbursement in hospitals to a blend of the ambulatory surgical center rate and hospital cost. Although the full impact of this will perhaps not be felt for the next year, or until the end of the hospitals' fiscal year, it is believed by many experts that the blended reimbursement is almost certain not to cover the hospital cost. Because hospitals will be receiving less reimbursement for nearly 900 procedures, it is generally believed that hospitals will be hard pressed to perform them. This change in reimbursement likely will have an impact beyond Medicare, because many state Medicaid plans and private payers also use this list for reimbursement. The new list of covered procedures in ambulatory surgical centers speaks not only of reimbursement. It speaks loudly of the government's and the public's acceptance of much more complex surgical procedures being performed in ambulatory sites. Some randomly selected procedures now approved include partial mastectomy with axillary dissection, breast reconstruction with muscle or myocutaneous flap, repair of nonunion or malunion humerus with iliac or other autograft (including taking graft), amputation of the arm or leg, embolectomy or thrombectomy, total excision of carotid tumor or gland with sacrifice or preservation of facial nerve, combined anteroposterior colporrhaphy with
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enterocele repair, exenteration of the orbit with temporalis muscle transplant, radical mastoidectomy, and many others. THE FUTURE
The 1970s and 1980s have seen consistent expansion of ambulatory surgery. This is true whether this growth is measured by the number of facilities providing ambulatory surgery, the number of patients receiving such care, the percentage of surgical patients choosing the ambulatory site, or the number of procedures chosen by surgeons and approved by third-party payers to be done on an ambulatory basis. We have seen earlier that the four forces that drive this expansion, improved and better operated facilities, new surgical techniques, improved anesthetic agents and practices, and regulations influencing ambulatory surgery, are all strong and appear to be gaining momentum. Patients, physicians, and the public have all accepted this method of delivering surgical care as being very appropriate, cost-effective, and satisfactory. Much of the evolving technology makes and will continue to make surgery easier on the patient and requiring less postoperative care and observation, making it ideal for the ambulatory setting. This is especially true of "video surgery" in which more and more abdominal and thoracic procedures are being done with small incisions, scopes, instruments, and cameras. With many ambulatory units already keeping patients for 23 hours and others very likely extending this to a 2or 3-day stay, the great majority of this huge volume of work will be shifted to the ambulatory setting. The first half of the 1990s will be remembered as a period of economic austerity and the absolute need for restraint of ever-increasing health care costs. The economic benefit of performing this magnitude of surgical cases out-of-hospital is not only apparent to all but is being demanded by business, insurors (especially those offering managed health care coverage), and government (the largest purchaser of health care), as well as individual patients. Regulations, imposed both by government and other third-party payers, will continue to force more procedures out of hospitals into ambulatory sites. Even if increasing pressure against "self-referral" should force physician-owners of ambulatory surgical centers to divest of the ownership of such units, the facilities will continue to operate and expand. When all of these factors are considered, it is quite appropriate in 1993, just as in 1986, to again predict "that the growth of ambulatory surgery will increase phenomenally in the years ahead .... growth in the foreseeable future appears almost unlimited." References 1. Abbey F: Same-Day Surg 16:29-31, 35-53, 1992 2. Battaglia Cl: FA SA Update VIII: 4-5, 1991
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3. Cares HL, Steinberg RS, Robertson ET: Ambulatory microsurgery for ruptured lumbar discs: Report of ten cases. Neurosurgery 22:523-526, 1988 4. Carr JA 1II: Recovery care concept gains ASC, hospital interest. Same-Day Surg 14:123-124, 1990 5. Cork RC, Scipione P, Vonesh MJ, et al: Propofol infusion vs thiopentaliisoflurane for outpatient anesthesia. Anesthesiology 69(suppl):3A, 1988 6. Davis JE: Major Ambulatory Surgery. Baltimore, Williams & Wilkins, 1986 7. Duncan T: New gallbladder removal technique cuts costs. Same-Day Surg 14:24-25, 1990 8. Holt BB: Procedure reduces endometrial lining, helps some patients avoid hysterectomy. Same-Day Surg 12:107-109, 1988 9. Klein L: New prostate procedure offers outpatient alternative. Same-Day Surg 13:141144, 1989 10. Kortilla K, Faure E, Apfelbaum J, et al: Recovery from propofol vs. thiopental isoflurane in patients undergoing outpatient anesthesia. Anesthesiology 69(suppl):3A, 1988 11. Levine B: Mobile overrating rooms offered as outpatient-surgery alternative. SameDay Surg 15:43-44, 1991 12. Mamakos MS: Ambulatory microvasovasostomy program achieving 80% fertility rate. Same-Day Surg 12:153-154, 1988 13. Mamakos MS: Surgeon does vas reversals as same-day procedure. Same-Day Surg 13:134-136, 1989 14. Newman J, Rose FA, Cantrell RW: Liposuction provides SOS facilities with safe new procedure. Same-Day Surg 11:145-149, 1987 15. Schreiner MS, Triebwasser A, Keon TP: Ingestions of liquids compared with preoperative fasting in pediatric outpatients. Anesthesiology 72:593-597, 1990 16. Schultz LS: Caution urged with outpatient laparoscopic cholecystectomy. Same-Day Surg 15:13-15, 1991 17. Stoker ME, Vose L O'Mara P, et al: Laparoscopic cholecystectomy: A clinical and financial analysis of 280 operations. Arch Surg 127:589-595, 1992 18. The Southern Surgeons Club: A prospective analysis of 1,518 laparoscopic cholecystectomies. NEJM 324:1073-1078, 1991 19. White F: Propofol: Pharmacokinetics and pharmacodynamics. Sem Anesthes 7(suppl 1): 1988 20. Yung-Fong S, Freniere S, Tillette T, et al: Comparison of propofol and thiopental anesthesia in outpatient surgery: Speed of recovery. Anesthesiology 69(suppl):3A, 1988
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