OUTPATIENT SURGERY Dr Abdollahi Another Name Ambulatory surgery

OUTPATIENT SURGERY Dr Abdollahi

Another Name Ambulatory surgery Day-case surgery Same-day surgery Come and go surgery

In the early 1900 s, an american anesthesiologist, Ralph Waters, opened an outpatient anesthesia clinic in Sioux City, lowa.

This facility, which provided care for dental and minor surgery cases, is generally regarded as the prototype for the modern freestanding ambulatory (and officebased) surgery center.

Interestingly, there was little , interest in ambulatory surgical care until the late 1960 s, when the first hospital-based ambulatory surgery units were developed.

Over the last 3 decades, outpatient surgery has grown at an exponential rate, progressing from the practice of performing simple procedures on healthy outpatients to encompassing a broad spectrum of patient care in freestanding ambulatory surgery centers. Formal development of ambulatory anesthesia as a subspecialty occurred with establishment of the Society for Ambulatory Anesthesia (SAMBA)in 1984 and the subsequent development of postgraduate subspecialty training programs.

By 1985, 7 million elective operations in the United States (over 30% of all elective surgical procedures) were performed on an ambulatory basis. Currently, more than 60%of all elective surgery is performed in the outpatient surgical setting, and it is expected that this number will increase to more than 70% in the near future.

The growth in ambulatory surgery would have not been possible without the development of improved anesthetic and surgical techniques. The availability of rapid, shorter -acting anesthetic, analgesic, and muscle relaxant drugs has clearly facilitated the recovery process and allowed more extensive procedures to be performed on an ambulatory basis, irrespective of preexisting medical Conditions.

Overnight admission An alternative to same- day surgical concept is a planned overnighte admission to the hospital after surgery. This approach (AM admit, 23 hour, short stay, come and stay ) is often classified as outpatient surgery and preserved many of its advantages.

Outpatient surgery allows a person to return home on the same day that a surgical procedure is performed.

Benefits of ambulatory surgery Patient preference, especially children and the elderly Lack of dependence on the availability of hospital beds Greater flexibility in scheduling operations Low morbidity and mortality Lower incidence of infection Lower incidence of respiratory complications Higher volume of patients (greater efficiency) Shorter surgical waiting lists Lower overall procedural costs Less preoperative testing and postoperative medication

FACILITY DESIGN AND SAFETY

Patient selection Characteristic of the patient type of operation psychosocial aspect of the patient Human and physical resource for pre & post op care Proximity to EMS Resource of skill set of both anesthesiologist and surgeon

Surgical procedures suitable for ambulatory surgery should be accompanied by minimal postoperative physiologic disturbances and an uncomplicated recovery. The primary predictors of prolonged stay or unanticipated admission after day-case surgery are related to the surgical procedure (e. g. , blood loss, pain, postoperative nausea and vomiting (PONV).

Operative procedures suitable for ambulatory surgery

Patients undergoing procedures that are likely to be associated with postoperative surgical complications or major fluid shifts should be admitted to the hospital overnight. Although autologous blood transfusions are used for more extensive outpatient plastic surgery (e. g. , reduction mammoplasty, liposuction), lengthy rocedures associated with excessive fluid shifts should be handled in an overnight (23 -hour) recovery facility. Similarly, operative procedures requiring prolonged immobilization and parenteral opioid analgesic therapy are more ideally suited to a 23 -hour stay. The availability of newer analgesic therapies (e. g. , continuous local anesthetic infusions) and ambulatory patient-controlled analgesia (e. g. , subcutaneous, intranasal, transcutaneous) may alter the latter recommendation in the future.

Duration of Surgery The duration of surgery in the ambulatory setting was originally limited to procedures lasting less than 90 minutes because investigators have found that the operating and anesthetic time is a strong predictor of postoperative complications (e. g. , pain, emesis)and delayed discharge, as well as unanticipated admission to the hospital after ambulatory surgery.

Patient Characteristics Most patients seen in ambulatory surgical facilities are classified as ASA physical status I or II. However, because of improved anesthesia and surgical care, increasing numbers of medically stable ASA physical status III (and even some IV) patients are able to undergo operations away from conventional medical centers.

American Society of Anesthesiologists (ASA) Classification of Physical Status I. A normal healthy patient -no discernible disease; animals entered for ovariohysterectomy, castration, declaw, cosmetic procedures II. A patient with mild systemic disease -skin tumor, fracture without shock, cruciate repair, uncomplicated hernia, cryptorchidectomy, localized infection, compensated cardiac disease III. A patient with severe systemic disease -fever, dehydration, anemia, cachexia, moderate hypovolemia IV. A patient with severe systemic disease that is a constant threat to life -uremia, toxemia, severe dehydration or hypovolemia, severe anemia, cardiac decompensation, emaciation, high fever V. A moribund patient not expected to survive 24 hrs. with or without surgery -extreme shock or dehydration, terminal malignancy or infection, severe trauma

Age is usually not a factor in the selection of the patient for outpatient surgery. Any infant with apnea in PACU or anemia regardless of age should be admitted to the hospital.

Contraindications in infant 1. premature infant with Hct <30% (apnea ) 2. history of RDS 3. History of sudden death in family

Susceptibility to Malignant Hyperthermia MH-susceptible patients can be successfully managed with non triggering anesthetics (e. g. , local anesthesia) in the outpatient setting.

Contraindications to Outpatient Surgery 1. Serious, potentially life-threatening diseases that are not optimally managed (e. g. , brittle diabetes, unstable angina, symptomatic asthma)

2. Morbid obesity complicated by symptomatic cardiovascular (e. g. , angina) or respiratory (e. g. , asthma) problems.

3. Multiple chronic centrally active drug therapies (e. g. , use of monoamine oxidase inhibitors such as pargyline and tranylcypromine) and active cocaine abuse because of the increased risk of intraoperative cardiovascular complications, including death.

4. Ex-premature infants less than 60 weeks' postconceptual age requiring general endotracheal anesthesia

5. Lack of a responsible adult at home to care for the patient on the evening after surgery.

PREOPERATIVE ASSESSMENT

Preoperative Preparation Nonpharmacologic Preparationsia

Pharmacologic Preparation

opioid Routine use of narcotic (opioid) analgesics for premedication is not recommended unless the patient is experiencing acute pain.

Prevention of Nausea and Vomiting

Butyrophenones Phenothiazines Gastrokinetic drugs (Metoclopramide and domperidone) Anticholinergics Dexamethasone, 4 to 8 mg intravenously, Nonpharmacologic Techniques Acupuncture and acupressure

Prevention of Aspiration Pneumonitis 1. H 2 Receptor Antagonists and Proton Pump Inhibitors 2. Antiacid 3. Gastrokinetic Agents (Metoclopramide) 4. NPO Guidelines

ANESTHETIC TECHNIQUES Quality, safety, efficiency, and the cost of drugs and equipment are all important considerations in choosing an anesthetic technique for outpatient surgery.

The ideal outpatient anesthetic should have a rapid and smooth onset of action, produce intraoperative amnesia and analgesia, provide good surgical conditions with a short recovery period, and have no adverse effects.

Outpatient surgery requires the same basic equipment as inpatient surgery for delivery of anesthetic drugs, monitoring, and resuscitation. Standard intraoperative monitoring equipment for outpatient operations should include an ECG, blood pressure cuff, pulse oximeter, and capnograph. If nondepolarizing muscle relaxants are used, a neuromuscular monitor should also be available. Increasingly, cerebral monitors are also being used to improve titration of anesthetic drugs and facilitate faster recovery.

The choice of anesthetic technique depends on both surgical and patient factors. For many ambulatory procedures, general anesthesia remains the most popular technique with both patients and surgeons.

Although central neuraxis blockade has traditionally been popular for peripheral extremity and lower abdominal procedures, its use in the ambulatory setting can delay discharge because of residual motor and sympathetic blockade.

Peripheral nerve blocks facilitate the recovery process by minimizing the need for postoperative opioid analgesics. Therefore, an increasing number of ambulatory cases are being performed with a combination of local anesthetic nerve blocks and intravenous sedation (so-called monitored anesthesia care [MAC]).

Despite a higher incidence of side effects, general anesthesia remains the most widely used anesthetic technique for managing ambulatory surgery.

General Anesthesia warming devices Tracheal intubation causes a high incidence of postoperative airwayrelated complaints, including sore throat, croup, and hoarseness

LMA The laryngeal mask airway (LMA) was first introduced in 1983 as an alternative to tracheal intubation or a facemask for airway management. When compared with anesthesia with a mask and oral airway, patients with an LMA had fewer desaturation episodes, fewer intraoperative airway manipulations, and fewer difficulties in maintaining an airway.

The incidence of postoperative sore throat after ambulatory surgery was 18% with an LMA versus 45% with a tracheal tube and 3% with a face mask.

The LMA frees the anesthesiologist's hands for record keeping, monitoring, and drug administration. Hand fatigue from maintaining the airway with a mask is also eliminated.

Although there is no ideal anesthetic drug or technique for outpatients, a vast array of pharmacologically active drugs, when combined in a rational manner and carefully titrated, can produce the desired anesthetic conditions with an acceptable recovery profile and reasonable cost.

An altenative to the LMA is the cuffed oropharyngeal airway device. Even though this device is easy to insert after induction without muscle relaxants, its ability to maintain an obstruction-free airway is less adequate than that of other curently used airway devices. Although the LMA device has been used in paralyzed patients undergoing laparoscopic surgery, most practitioners in North America still prefer tracheal intubation in these situations to minimize the ris. K of gastric distention and ensure adequate ventilation in the Trendelenbmg posinduction.

Anesthetic Drugs Induction of general anesthesia is typically accomplished with a rapidacting intravenous anesthetic. Propofol has virtually replaced the barbitmates for induction of anesthesia in the ambulatory setting because of its favorable recovery profile

The most popular technique for maintenance of anesthesia is a combination of a volatile anesthetic and nitrous oxide. The extremely low solubility of nitrous oxide and the newer volatile anesthetics (sevoflurane and desflurane) contributes to a more rapid onset and recovery from general anesthesia.

Although it has been suggested that the use of nitrous oxide is associated with PONY, controlled studies have questioned the clinical importance of nitrolls oxide in producing this side effect. When compared with a target-controlled infusion of propofol for maintenance of anesthesia, the use of desflurane or sevoflurane produced similar anesthetic conditions with shorter emergence times and at a lower drug cost.

Inhaled Anesthetics Volatile anesthetics are most commonly used for maintenance of ambulatory anesthesia. isoflurane was the most commonly used anesthetic for maintenance of ambulatory anesthesia before the introduction of the less soluble drugs sevoflurane and desflurane.

Barbiturates Thiopental (3 to 6 mg/kg) is the prototypical intravenous induction drug with a rapid onset and a relatively short duration of action as a result of redistribution of the drug. However, thiopental impairs fine motor skills for several hours after surgery and can produce a "hangover“ sensation.

Methohexital appears to be associated with shorter awakening times, but complete recovery of fine motor skills may still require 6 to 8 hours after an induction dose. when compared with thiopental, methohexital is associated with a higher incidence of pain on injection, involuntary muscle movement, and hiccoughing

Although propofol resulted in faster emergence from anesthesia and a lower incidence of PONV than methohexital, the barbiturate compared favorably with propofol when used for induction only in outpatient procedures lasting longer than 90 minutes. Unfortunately, methohexital is no longer widely available.

Benzodiazepines Although midazolam (0. 2 to 0. 4 mg/kg IV) has been used for induction of anesthesia in outpatients, its onset of action is slower and recovery is prolonged in comparison to the barbiturate compounds and propofol. When combined with nitrous oxide and a potent opioid analgesic, lower doses of midazolam (0. 1 to 0. 15 mg/kg) can be used to induce general anesthesia. If midazolam is used for induction and flumazenil, a specific benzodiazepine antagonist, is administered at the end of surgery, prompt recovery can be achieved after outpatient surgery. When compared with propofol, recovery after flumazenil antagonism of midazolam anesthesia offered no clinically significant advantages.

Etomidate (0. 2 to 0. 3 mg/kg) has also been used for induction and maintenance (1 to 3 mg/min) of general anesthesia during short outpatient procedures. Recovery tends to be faster than after thiopental and compares favorably with methohexital. Disadvantages of etomidate include pain on injection, a high incidence of PONV, myoclonic movements, and transient suppression of adrenal steroidogenesis. Given its side effect profile, the use of etomidate should be restricted to clinical situations in which its hemodynamic stability offers a distinctive advantage over the other available induction drugs (e. g. , elderly outpatients with clinically significant coronary artery or cerebrovascular disease).

ketamine Ketamine is a unique sedative-analgesic that can be used for both induction and maintenance of general anesthesia. However, ketamine compares unfavorably with both the barbiturates and propofol for minor gynecologic procedures because of its prominent psychomimetic effects and higher incidence of PONV during the early postoperative period. Use of the more potent S(+)-isomer of ketamine may decrease some of the adverse effects associated with the racemic mixture in the ambulatory setting. Premedication with a benzodiazepine (e. g. , midazolam, 0. 05 mg/kg IV) decreases the incidence of ketamine-induced emergence reactions. Small doses of ketamine (10 to 20 mg IV) have been used as an alternative to potent opioid analgesics during induction of anesthesia with propofol.

propofol Propofol is an intravenous anesthetic with an extremely high metabolic clearance rate Although propofol costs more than the barbiturate anesthetics do, the use of propofol may contribute to significant savings because of decreased recovery costs. When compared with methohexital, the use of propofol was associated with fewer perioperative side effects (e. g. , less hiccoughs, nausea, and vomiting) and faster overall recovery times. the faster intermediate recovery with propofol-based anesthetics may also yield significant savings in nursing costs (e. g. , less overtime). For example, a I 5 -minute reduction in the phase I recovery room stay could save 1000 nursing hours in a 4, 000 -case per year ambulatory surgical.

Midazolam remains the most commonly used anxiolytic premedication for pediatric outpatients. After receiving O. 5 mg/kg of midazolam orally, children can be easily separated from their parents within 30 minutes without prolonging the discharge time even after short surgical procedures. . .

rectal methohexital is administered (20 to 30 mg/kg) before volatile anesthesia, recovery times will be prolonged.

Rectal etomidate (6 mg/kg) or ketamine (5 to 10 mg/kg) can roduce a rapid onset of hypnosis without cardiorespiratory epression in children undergoing outpatient procedures. Although ketamine (2 to 4 mg/kg intramuscularly) can be an extremely useful drug for induction of anesthesia in an uncooperativ e or mentally retarded child, home readiness is delayed when larger doses of ketamine (>5 mg/kg) are combined with volatile anesthetics. In addition, psychomimetic reactions have been reported in children after ketamine administration

Volatile anesthetics are associated with a higher incidence of vomiting in the early recovery period than propofol based anesthetic techniques.

Opioid Analgesics Opioid compounds are frequently administered in the immediate preinduction period to suppress autonomic responses to tracheal intubation and during the maintenance period to treat acute autonomic responses to painful (noxious) stimuli.

The use of small doses of potent opioids (e. g. , fentanyl, 1 to 2 µg/kg, alfentanil, 15 to 30 µg/kg, sufentanil, 0. 15 to 0. 3µg/kg, or remifentanil, 0. 5 to 1µg/kg) can effectively attenuate the cardiostimulatory response to laryngoscopy and intubation, as well as the skin incision.

Remifentanil is an ultrashort-acting opioid analgesic with potency similar to that of fentanyl. It is rapidly metabolized by nonspecific tissue esterases, a process that allows for rapid systemic elimination, with a halflife of 8 to 10 minutes.

Morphine, hydromorphone, oxymorphone, and meperidine have all been used in outpatient anesthesia However, these opioid compounds are less popular than the more potent, rapid, and shorter-acting opioid analgesics (e. g. , fentanyl, sufentanil, alfentanil, and remifentanil).

morphine was associated with increased nausea and vomiting in the postdischarge period. Motion-induced emesis is a major concern when morphine and its more lipophobic congeners are used in the ambulatory setting.

Muscle Relaxants Many superficial outpatient surgical procedures do not require the use of neuromuscular relaxants. When remifentanil is used in combination with propofol for induction of anesthesia, tracheal intubation can be performed without any muscle relaxants.

Succinylcholine remains the most commonly used muscle relaxant to facilitate tracheal intubation in the ambulatory setting because it has a rapid onset and its short duration of action obviates the need for reversal drugs.

Use of the short- and intermediateacting nondepolarizing muscle relaxants (e. g. , cisatracurium, mivacurium) allows reversal of neuromuscular blockade even after brief surgical procedures.

Cost-effective technique involves the use of succinylcholine for tracheal intubation followed by small (4 to 8 mg) bolus doses of mivacurium during the maintenance period. This relaxant technique minimizes the need for muscle relaxant reversal drugs after short laparoscopic procedures.

Mivacurium may be advantageous for use during the maintenance period because reversal is seldom required if the drug is properly titrated

Antagonist (Reversal) Drugs antagonists may also produce unwanted side effects (e. g. , dizziness, headaches, PONV) that should be considered before routinely using these drugs. In addition, because their duration of action is often shorter than the agonist (e. g. , naloxone, flumazenil), a "rebound“ of the agonist effect may occur.

Pediatric Considerations In unruly, frightened, or mentally retarded children, preoperative sedation is required before taking the patient into the operating room. In general, sedative premedication is not offered to children younger than 12 months, but it is often used for toddlers or preschool-aged children.

Midazolam remains the most commonly used anxiolytic premedication for pediatric outpatients. After receiving O. 5 mg/kg of midazolam orally, children can be easily separated from their parents within 30 minutes without prolonging the discharge time even after short surgical procedures.

REGIONAL ANESTHESIA Regional anesthesia can offer many advantages for the ambulatory patient population.

Epidural and Spinal Techniques Spinal anesthesia is the simplest and most reliable regional anesthetic technique. However, the incidence of side effects is surprisingly high when used in the ambulatory setting. The most troublesome complications of outpatient spinal anesthesia are residual effects of the block on motor, sensory, and sympathetic nervous system function, which can contribute to delayed ambulation, dizziness, urinary retention, and impaired balance. In addition, post-dural puncture headache and backache remain problems after spinal anesthesia.

Epidural anesthesia is technically more difficult to perform, it has a slower onset of action, the potential for intravascular or intrathecal injection exists, and it is associated with a greater chance of an incomplete sensory block than spinal anesthesia.

Intravenous Regional Anesthesia For short superficial surgical procedures « 60 minutes) limited to a single extremity, the intravenous regional (Bier) block technique with 0. 5% lidocaine is a simple and reliable technique.

The addition of adjuvant (e. g. , ketorolac, 15 mg, clonidine, 1 µg/kg, dexmeditomidine, 0. 5 /µgkg) will improve the quality of postoperative analgesia.

Peripheral Nerve Block

Monitored Anesthesia Care The combination of local anesthesia with intravenous sedative and analgesic drugs is extremely popular in the ambulatory setting. It has been suggested that up to 50% of all outpatient procedures could be performed with a MAC technique and that the cost of perioperative care can be reduced by up to 80% in comparison to general anesthesia.

Many different sedative-hypnotic drugs have been used during MAC (including barbiturates, benzodiazepines ketamine, and propofol) with a wide variety of delivery systems (e. g. , intermittent boluses, variable-rate infusion, target-controlled infusion, patient-controlled sedation). The most commonly used sedation techniqueis a small dose of midazolam (1 to 2 mg) or propofol (0. 5 to I mg/kg), or both, followed by a propofol infusion at 25 to 100 µg/kg/min. Methohexital has also been used successfully during MAC as intermittent boluses (10 to 20 mg) or as a variable-rate infusion (1 to 3 mg/min).

Cerebral Monitoring ; Monitoring patient vital signs remains the most common method for determining the "depth of anesthesia" during surgery. Recent studies have suggested that the use of cerebral monitoring improves early recovery after general anesthesia in the ambulatory setting because of its ability to minimize both "overdosing" and "underdosing “ with both intravenous (e. g. , propofol) and inhaled anesthetic (e. g. , sevoflurane and desflurane) drugs during the maintenance period.

Optimal Anesthetic Techniques The optimal anesthetic technique in the ambulatory setting would provide for excellent operating conditions, rapid "fast-track" recovery without postoperative side effects or complications, and a high degree of patient satisfaction.

Fast-Tracking Concepts Bypassing the PACU has been termed "fasttracking" after ambulatory surgery. If careful titration of short-acting drugs permits safe transfer of patients directly from the operating room suite to a less labor intensive recovery area, some patients can be discharged home within 1 hour after surgery.

Multimodal Approaches to minimizing side Effects 1. Minimally invasive surgical approaches (e. g. , laparoscopic adrenalectomy and nephrectomy arthroscopic knee and shoulder reconstructions).

2 -For routine antiemetic prophylaxis, the most cost-effective combination consists of low dose droperidol (0. 5 to 1 mg) and dexamethasone (4 to 8 mg).

3 -The addition of low-dose ketamine (75 to 150 µg/kg) to a multi modal analgesic regimen improved postoperative analgesia and functional outcome after painful orthopedic surgery procedures. Acetazolamide (5 mg/kg IV) reduces referred pain after laparoscopic surgery with CO 2 insufflation.

4 - One of the keys to facilitating the recovery process is the routine use of local anesthetics as part of a multimodal regimen. After arthroscopic knee surgery, instillation of 30 m. L of O. 5% bupivacaine into the joint space reduces postoperative opiate requirements and permits earlier ambulation and discharge. The addition of morphine (1 to 2 mg), ketorolac (15 to 30 mg), clonidine (0. 1 to 0. 2 mg), and/or triamcinolone (10 to 20 mg) to the intra-articular local anesthetic solution can further reduce pain after arthroscopic surgery.

DISCHARGE CRITERIA Discharge after General Anesthesia and Monitored Anesthesia Care

The three stages of recovery after ambulatory surgery are the early, intermediate, and late recovery periods. The early and intermediate recovery stages occur in the ambulatory surgical facility, whereas late recovery refers to the resumption of normal daily activities and occurs after discharge home

Early recovery The time interval during which patients emerge from anesthesia, recover control of their protective reflexes, and resume early motor activity. During this phase of recovery, patients are cared for in the PACU, where their vital signs and oxygen saturation are carefully monitored and supplemental oxygen, analgesics, or anti emetics can be readily administered.

Intermediate recovery During the intermediate recovery period, patients are usually cared for in a reclining chair and progressively begin to ambulate, drink fluids, void, and prepare for discharge. Most ambulatory surgical facilities have a separate area for the intermediate recovery of outpatients to a homeready state

late recovery The late recovery period starts when the patient is discharged home and continues until functional recovery is achieved and the patient is able to resume normal activities of daily living. The anesthetics, analgesics, and anti emetics can also have an effect on the patient's recovery during the postdischarge period. However, the surgical procedure itself has the highest impact on the patient's full functional recovery.

Factors that predict a more prolonged stay in the day-surgery unit include female gender, advanced age, longer operations, large fluid or blood loss and opioid use, nondepolarizing muscle relaxants, postoperative pain and PONY, and spinal anesthesia.

Guidelines for safe discharge from an ambulatory surgical facility include stable vital signs, return to baseline orientation, ambulation without dizziness, minimal pain and PONY, and minimal bleeding at the surgical site.

post anesthetic discharge scoring (PADS) system (1) vital signs, including blood pressure, heart rate, respiratory rate, and temperature (2) ambulation and mental status (3) pain and PONY (4) surgical bleeding (5) fluid intake/output Patients who achieve a score of 9 or greater and have an adult escort are considered fit for discharge (or home ready).

. Discharge after regional Anesthesia With spinal or epidural anesthesia, it is generally accepted that motor and sensory function returns before sympathetic nerve function. Residual blockade of the sympathetic nerve supply to the bladder and urethra may cause urinary retention.

Before ambulation, these patients should have normal perianal (S 4 -5) sensation, the ability to plantar-reflex the foot, and proprioception of the big toe. Thus, discharge criteria after spinal and epidural anesthesia should include the return of normal sensation, muscle strength, and proprioception, as well as the return of sympathetic nervous function.

Controversies Related to Discharge Criteria well-hydrated outpatients can be safely discharged home without demonstrating an ability to tolerate oral fluids after surgery.

The requirement to void before discharge has also been challenged. The inability to void and urinary retention may be caused by pain (which inhibits normal bladder detrusor function) or by opioid analgesics, spinal or epidural anesthesia, administration of drugs with anticholinergic effects, and prolonged blockade of the autonomic innervation to the bladder. Patients may be discharged earlier if voiding is not a discharge requirement. Delaying discharge for voiding after spinal or epidural anesthesia with short-acting local anesthetics is unnecessary in low-risk patients (e. g. , age <70 years; no hernia, rectal, or urologic surgery; no history of voiding problems).

1. The majority of operations today are performed on an outpatient basis. 2. Although restrictions on the types of cases appropriate for ambulatory surgery have been reduced, hospital admissions after outpatient procedures should not be common. 3. Preoperative administration of the combination of midazolam and fentanyl can make patients sleepy up to 8 hours later. Preoperative sedation is not required for every patient. 4. Postoperative pain is less after regional anesthesia, although performing a block requires more time than does induction of general anesthesia and has a higher incidence of failure.

5. Even when thiopental is used only for induction, psychomotor impairment can be evident up to 5 hours after administration compared to only 1 hour after propofol. 6. Although some drugs have faster recovery time than others, actual discharge from an ambulatory center may depend more on administrative issues, such as obtaining the written discharge order from the surgeon or anesthesiologist. 7. Nausea probably is the most important factor contributing to a delay in discharge and an increase in admission after ambulatory surgery. Combination therapy probably is the most effective way to control postoperative nausea and vomiting. 8. Pain may be associated with nausea, and treatment of the pain frequently decreases nausea.

KEY POINTS 1. The continued growth in ambulatory surgery is related to expansion in minimally invasive surgical techniques and office-based procedures. 2. Preexisting medical conditions are rarely, if ever an exclusionary criterion for ambulatory surgery. 3. Routine laboratory testing is not recommended before ambulatory surgery. 4. The choice of anesthetic technique has a significant effect on postoperative side effects and discharge time. The use of local anesthesia with sedation, so-called monitored anesthesia care, is associated with the fewest side effects and the shortest time to discharge home. 5. The use of propofol for induction or maintenance of anesthesia (or both) is associated with a reduced incidence of postoperative nausea and vomiting

6. The use of desflurane or nitrous oxide (or both) in conjunction with antiemetic prophylaxis will facilitate the "fast-track" recovery process. 7. The use of potent opioid analgesics (e. g. , fentanyl, sufentanil) in combination with local anesthetics will decrease the time to discharge home after spinal anesthesia. 8. Multimodal ("balanced") analgesic and antiemetic regimens will allow most outpatients to be fasttracked after ambulatory surgery under general anesthesia. 9. Fast-tracking after ambulatory surgery is accomplished by taking the patient directly from the operating room to the day-surgery step-down unit ("bypassing the PACU")or simply discharging the patient home from the PACU("PACUbypassing"). 1 O. Outcomes after ambulatory (and office-based) surgery are no different than after inpatient (hospital-based) surgery procedures. Recent data suggest that for elderly patients, the surgical outcome may be improved.

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