Chapter 37
Outpatient Anesthesia
The concept of outpatient anesthesia is not unique to the past three decades. It was introduced in dentists’ offices with the administration of nitrous oxide. Physicians’ offices were next to offer this type of service for superficial procedures that required at most the administration of local anesthesia. In 1909, Nicoll1 first reported on 8988 outpatient surgical procedures performed at the Glasgow Royal Hospital for Sick Children. In 1916 in Sioux City, Iowa, Waters2 opened the first freestanding unit designed for outpatient surgery.
The evolution of and demand for outpatient care have not slowed since first described by these pioneers. Surgical innovation, new anesthetic drugs and techniques, and changes in insurance carrier demands have increased the type and number of procedures performed at ambulatory care centers or traditional hospital operating rooms. Within the United States, outpatient procedures at freestanding centers increased nearly 300% between 1996 and 2006. An estimated 35 million outpatient surgical procedures were performed in 2006. The most common ambulatory procedures included myringotomy and tonsillectomy for patients under 15 years of age, large intestine endoscopy and therapeutic injection for patients aged 15 to 44 years, and intraocular lens extraction for patients 75 years or older. Currently, more than 62% of all elective procedures are performed on an outpatient basis.3 In addition, difficult procedures performed even on patients with complex medical conditions are more routinely being performed on an outpatient basis. It is the responsibility of the attending anesthesia provider to ensure that these complex medical conditions are managed optimally before, during, and after the procedure.
It is expected that the patient will enter the outpatient surgical care facility, undergo the procedure, and then be released without needing an overnight stay. Outpatient surgery, in addition to office-based and free-standing ambulatory surgery centers, includes the “23-hour observation” patient, who may be admitted to the inpatient or overnight facility yet is discharged before staying in the hospital 24 hours. Surgical procedures requiring the expertise of an anesthesia provider in the office setting are becoming increasingly popular. Office-based surgery can be performed more efficiently and at lower cost than surgery performed in the hospital.4 Presently, 12 million operations annually, representing about 10% of all outpatient procedures, are performed in an office-based setting.5 Optimal anesthesia and surgical techniques for office-based surgery are similar to ambulatory procedures performed at traditional ambulatory surgical centers. Although office-based surgery can be performed safely, it is not without risk. Current issues of discussion include patient and procedure selection, recovery, complication management, perioperative management, and facility requirements.6 Office-based anesthesia practice standards and guidelines have been developed by the American Association of Nurse Anesthetists (AANA),7 the American Society of Anesthesiologists (ASA),8 and the Joint Commission.9
Features of Outpatient Surgery
Financial
An advantage of ambulatory surgical settings has been the economic benefit for consumers, third-party payers, and medical facilities. Patients may benefit not only from reduced medical cost but also from minimized costs of outside child care and from resumption of normal living activities at an earlier time. Third-party payers concerned about cost containment are increasingly identifying procedures that may be performed only in the outpatient setting. Cost savings exceeding 50% have been reported for selected surgeries (e.g., laparoscopic cholecystectomy) performed on an outpatient basis.10 Ambulatory centers, secondary to their design, facility layout, and patient selection, tend to operate more efficiently than hospital-based operating theaters in regard to surgical volume.
Medical
One medical advantage of ambulatory surgery is the increased availability of hospital beds for patients requiring hospital admission. For patients who are susceptible to infection (e.g., children, immunosuppressed patients, cancer patients, and transplant recipients), minimizing time and contact in the inpatient hospital setting may decrease the risk of nosocomial infections.11
Patient Satisfaction
Patients report greater satisfaction with outpatient procedures because of shorter waiting times and lower costs.12,13 Delays secondary to lack of available beds, as seen with inpatient facilities, are less likely to occur.
Social
Children benefit from outpatient surgery because it minimizes separation from parents and causes less disruption in a child’s feeding schedule. The continued presence of and care offered by the parents are especially beneficial for children with mental or physical impairments.14 Geriatric patients show better cognitive and physical capacity when separation from familiar surroundings and family is minimized. The elderly are better able to maintain their normal living routines (e.g., diet, medication, and sleep pattern). Postoperative confusion is decreased in geriatric patients undergoing outpatient procedures because they receive less medication and are returned to a familiar environment sooner than their inpatient counterparts.15
Disadvantages
The outpatient setting may have several disadvantages:
• The degree of patient privacy is less than that in the inpatient setting.
• The patient must make multiple trips to the physician’s office or the ambulatory setting for evaluation and screening.
• Adequate home care must be ensured once the patient is discharged from the facility after surgery.
• Compliance and efficacy related to preoperative and postoperative instructions may not be as good as when the patient is admitted to the hospital before surgery.
• Because of the emphasis on efficiency, children have less time to adapt to the surgical setting than they would as inpatients.
• Observation time and monitoring for the occurrence of adverse events are decreased in the outpatient setting.
• Management of complications can be problematic at a free-standing or office-based facility secondary to a lack of resources.
Demographic Considerations
Patients of any age can receive outpatient anesthesia; age should not be a limiting factor when determining appropriateness for ambulatory procedures. Approximately 6% of outpatients are younger than 15 years, and more than 14% are at least 75 years of age.3 More than 60% of all anesthesia administered for pediatric surgery is performed on an outpatient basis.14
Surgical Time
Earlier guidelines recommended limiting the amount of time of an outpatient surgery to less than 1.5 to 2 hours.16 The reasoning was that the longer surgery lasts, the more likely patients will experience severe pain or vomiting.17,18 Surgical time exceeding 2 hours was also thought to be a strong predictor for delayed discharge and unplanned hospital admission postoperatively.19 However, other factors such as the skill of the surgeon, the type of surgery performed, the patient’s condition, and the anesthetic technique used must be considered. Arbitrarily limiting the length of surgery to less than 2 hours is no longer considered necessary; procedures exceeding 4 hours are routinely performed without complications in ambulatory centers.
Suitable Procedures
The list of procedures suitable for the ambulatory setting is constantly evolving. Endoscopy of the large and small intestine is the most common type of outpatient procedure, and ophthalmologic surgery is the second most common.3 The outpatient surgical procedure should not involve extensive blood loss or physiologic shifts of considerable fluid volumes because these processes necessitate protracted patient observation and hydration. In the past, the potential for blood transfusion implied the need for the procedure to be conducted at an inpatient facility. Now the increasing popularity of autologous blood donation for possible future transfusion has facilitated the application of transfusion during or after the outpatient surgery when needed.20
The list of surgical procedures deemed acceptable for outpatient surgery is ever expanding; routinely included are surgeries such as laparoscopic cholecystectomy,21 lumbar laminectomy,22 cervical laminectomy and fusion,23 thyroidectomy,24 hysterectomy,25 and tonsillectomy.26 The norm regarding suitable outpatient procedures continues to be challenged, with the addition of more potentially higher-risk procedures, that is, craniotomy for tumor,27–29 adrenalectomy,30 and gastric bypass surgery.31 Facilities with a 23-hour observation area designed for extended patient assessment is often the desired location for procedures such as outpatient tonsillectomy and higher-risk procedures.
Patient Selection
• The anticipated surgical procedure for the patient. The proposed surgery should have an insignificant incidence of intraoperative and postoperative problems and should not require intense postoperative patient management.
• The physical and psychosocial health of the patient. The patient is ideally in his or her usual good health, or if ill, the condition should be well controlled. A reduction in postoperative complications has been shown if the patient’s medical condition is stable for at least 3 months before surgery.32 The patient and family should be receptive to the outpatient philosophy and the perioperative adaptations that will be required of them.
• The surgeon’s skills and cooperation. Early referral to the anesthesia department for patients of questionable appropriateness helps streamline the outpatient process and minimize delays on the day of surgery.
Selection Criteria
The patient with a history of substance abuse should be evaluated before the day of surgery. Counseling for such patients includes the warning that preoperative substance abuse will lead to cancellation of the surgery. A distinction between long-term and acute substance abuse must be made. A urinary drug screen should be performed in patients suspected of substance abuse. The patient with signs of acute substance intoxication is an inappropriate ambulatory surgery candidate because of the increased likelihood of impaired autonomic and cardiovascular responses. The surgery should be rescheduled after the patient is detoxified and treated. Patient management strategies should emphasize methods of minimizing postoperative pain, because substance abusers are typically intolerant to pain. Regional or local anesthetic techniques, if their use is suitable to the surgeon and appropriate for the type of operation being performed, may be used if the patient wishes to abstain from sedatives and opioids. Postoperatively, pain may be minimized by the use of local wound infiltration, regional techniques, and the prophylactic use of nonsteroidal analgesics. Placing a catheter in the wound and instilling local anesthesia, either continuously or intermittently, has been shown to prolong pain relief and improve patient satisfaction and should be considered for this patient population.33
Age
Patient age by itself should not be the deciding factor for outpatient suitability. Meridy34 retrospectively examined the charts of patients ranging in age from 9 months to 92 years and noted that most perioperative complications occurred in the 20- to 49-year age group. Patients older than 85 years, who required multiple hospitalizations within 6 months of the surgery, have been shown to have an increased risk of unanticipated hospitalization and death after outpatient surgery.35 Although multiple medications and preexisting comorbidities are more likely in the elderly, there is a paucity of data supporting increased adverse outcome in these high-risk elderly patients.36
Premature Infant
• Not have fully developed gag reflexes (and thus be more prone to aspiration of liquid or solid food)
• Have immature temperature control and be susceptible to the effects of hypothermia, which could contribute to postoperative apnea
• Demonstrate immature brainstem functioning, which predisposes the infant to pathologic respiratory conditions
The infant with a hemoglobin value less than the predicted normal value for that age will require additional evaluation before surgery. Hemoglobin values in the premature infant may drop to between 7 and 8 g/100 mL, 1 to 3 months after birth.37 The presence of anemia (hematocrit less than 30%) may increase the incidence of apnea in the newborn.38 Some investigators have recommended delaying elective surgery until the hematocrit is increased to greater than 30% through supplementation of iron intake.39
In the perioperative period, the preterm infant is at greater risk for developing respiratory complications, including apnea, than is the full-term infant.38 The preterm infant is susceptible to short apnea (6 to 15 seconds), prolonged apnea (greater than 15 seconds), or periodic breathing (three or more periods of apnea of 3 to 15 seconds separated by less than 20 seconds of normal respiration). Short or prolonged apnea and periodic breathing predispose the infant to hypoxemia and bradycardia. An obstructive component that leads to quicker oxyhemoglobin desaturation appears to be part of postoperative apnea in these infants.40 These infants have developed prolonged apnea as late as 12 hours after surgery.38
The older the infant, the less likely that respiratory complications such as apnea will occur. In evaluating the suitability of a former preterm infant for outpatient surgery, conservative measures are best; inpatient status should be assigned if significant concerns exist. These patients benefit from the intensive monitoring available in the inpatient setting. Much discussion has been held as to the postgestational age (gestational age plus postnatal age) at which the former preterm infant may safely undergo outpatient anesthesia. Healthy former premature infants whose postgestational age is less than 50 to 60 weeks41,42 should be admitted to the hospital for extended monitoring. Postoperative apnea has been described even in the full-term infant.44 The ability to exactly predict the susceptibility of an infant to postoperative apnea is lacking.45 Patients should be evaluated individually for appropriateness for outpatient surgery, and consideration should be given to growth and development, feeding problems, upper respiratory tract infections (URTIs), apneic history, and disorders of metabolic, endocrine, neurologic, or cardiac systems. All infants with a history of prematurity should be closely observed for signs of apnea and bradycardia. If any of these signs are evidenced in the postanesthesia care unit, patients should be admitted and observed. An infant with a history of apnea or bradycardia must be apnea free and without monitoring for at least 6 months to be considered for outpatient surgery.43 Efforts should be made to schedule surgery for these patients as early in the day as possible to allow for extended observation time.
Beyond simply delaying surgery, attempts to minimize the likelihood of postoperative apnea in susceptible infants have been examined. Spinal anesthesia without sedation resulted in less prolonged apnea, oxyhemoglobin desaturation, and bradycardia than did general anesthesia or spinal anesthesia with ketamine sedation.39 However, apnea and delayed respiratory failure have been reported in children who have had spinal or caudal anesthesia.45 Infants treated with endotracheal intubation or mechanical ventilation (or both) for respiratory distress syndrome at birth have been shown to have abnormal arterial blood gas values and abnormal pulmonary function results as late as 1 year after treatment.46 Infants exhibiting signs of bronchopulmonary dysplasia should not be considered for outpatient surgery.47 Patients with a history of bronchopulmonary dysplasia are at risk for sudden infant death.48
Infants with a history of apneic events or who have siblings who developed sudden infant death syndrome (SIDS) are at risk for SIDS. The greatest at-risk age for the development of SIDS is between 1 month and 1 year of age.49 In infants who have lost a sibling to SIDS, the risk of dying from the same syndrome is four to five times that of the general population.50 Patients at risk for the development of SIDS should not be considered for outpatient surgical procedures until they are at least 6 months to 1 year old.51
Full-Term Infant
Healthy, full-term infants (older than 37 weeks’ gestational age at birth) can be considered for minor outpatient surgery. Full-term infants with histories of apneic episodes, failure to thrive, and feeding difficulties are not suitable candidates for outpatient surgery. Infants with a history of respiratory difficulties at birth are not suitable outpatient candidates unless they are free of respiratory symptoms at the time of surgery and at the time of hospital discharge.51 There are no formal practice guidelines from major anesthesia or pediatric organizations regarding outpatient surgery in infants. However, individual hospitals frequently establish a cutoff age of 50 to 56 weeks of postconceptual age in infants born before 37 weeks, and also consider factors such as anemia, prior apnea, and coexisting disease. Postoperative monitoring recommendations range from 12- to 24-hour admission for cardiorespiratory monitoring. Some facilities also restrict day surgery procedures for term infants to only those infants older than 44 to 46 weeks of postconceptual age, or the facilities require a longer observation period (e.g., 4 hours) in phase II recovery.52 Some evidence-based suggested guidelines are listed in Box 37-1.
Geriatric Patient
The decision of whether to perform ambulatory surgery on a geriatric patient (age 65 years or older) should be individualized and based on physiologic age rather than on chronologic age. Existing medical problems are a concern when considering the geriatric patient for outpatient surgery. There are more concomitant age-related diseases that should be optimally treated preoperatively in this group of patients. Patient age exceeding 85 years is a predictor of hospital admissions after outpatient surgery.35,53 Thoughtful preoperative planning for the elderly patient’s post-discharge care is paramount to ensure a safe and successful outpatient experience. The elderly population presenting for outpatient surgery has increased dramatically and will continue to increase as the population ages.54 Appropriate home care and transportation to and from the outpatient center with a responsible caregiver must be ensured.
Special Considerations
Convulsive Disorders
Surgery for patients with seizure disorders should be scheduled early in the day so patients can be observed for 4 to 8 hours after the operation before they are discharged. It is important to establish the patients’ ability to maintain their schedule for anticonvulsant medications. Patients with uncontrolled seizure activity are not deemed appropriate for outpatient surgery by most institutions.
Cystic Fibrosis
The extent of pulmonary involvement is the primary determinant of appropriateness for ambulatory surgery in patients with cystic fibrosis. Such patients should be evaluated several days before the proposed surgery; patients with symptomatic respiratory distress are better treated in an inpatient setting, where appropriate respiratory-care management and hydration can be administered.55 Protective airway measures should be instituted in the cystic fibrosis patient secondary to an increased risk of gastroesophageal reflux disease and pulmonary aspiration.56
Malignant Hyperthermia Susceptibility
Malignant hyperthermia susceptibility is impossible to predict because it occurs in phenotypically normal individuals.57 A malignant hyperthermia (MH)–susceptible patient is defined as having one or more of the following58–63:
2. Masseter muscle rigidity with previous anesthesia
3. A first-degree relative with history of an MH episode or positive muscle biopsy
4. Diseases with known mutations on chromosome 19; may include, but are not limited to, central core myopathy, King-Denborough syndrome, Native American myopathy, and hypokalemic periodic paralysis
Diseases not associated with MH susceptibility include mitochondrial myopathies, Noonan syndrome, osteogenesis imperfect, and neuroleptic malignant syndrome.57
The MH-susceptible patient who has received a trigger-free uneventful anesthetic does not require overnight hospitalization based exclusively on being MH susceptible. The ambulatory facility should have the requisite monitoring and resuscitation capabilities, including a minimum of 36 vials of dantrolene, for managing the MH patient.64 A point-of-care monitor (capable of measuring blood gases and electrolytes) and urinalysis with a dipstick (to detect myoglobinuria) are useful monitoring devices used in the free-standing ambulatory center.65 The patient should be scheduled as early in the day as possible to allow for extended patient observation for at least 1 hour in the postanesthesia care unit (PACU) plus an additional hour in phase 2 recovery, and the lack of symptoms of MH should be ensured before discharge is considered.66 A patient who exhibits marked rigidity of the jaw muscles should not be discharged. Overnight observation is required for temperature rise, myoglobinuria, elevated creatine kinase (CK) levels, or progression to an MH episode. Patients who experience milder increases in jaw tension should be observed for signs and symptoms of MH for at least 12 hours. If there is evidence of myoglobinuria (i.e., dark, cola-colored urine), elevated temperature and pulse rate, or abnormality of acid-base balance, the patient should be emergently transferred and admitted to the nearest full service facility and observed overnight.66,67 Written discharge instructions should include: (1) how to monitor the patient’s temperature at home, (2) how to recognize the signs and symptoms of MH, and (3) contact information if emergency medical advice is required.68
Morbid Obesity
The uncomplicated morbidly obese patient is an appropriate candidate for select outpatient surgery.69 The morbidly obese patient with significant preexisting cardiac, hepatic, pulmonary, or renal disease has to be evaluated on an individual basis and may best be managed as an inpatient. Late problems are more likely to occur when the body mass index (BMI) reaches 35 to 40 kg/m2; this was once considered to be the cutoff point for ambulatory surgery. With the introduction of select bariatric procedures into the outpatient setting, this exclusionary criterion has been reevaluated. A higher incidence of postoperative hypoxemia has been observed in patients with a BMI of 35 kg/m2 or higher.70 However, unanticipated hospital admission after ambulatory surgery was not increased in obese patients with an average BMI of 44 kg/m2.71 The laparoscopic adjustable gastric banding procedure has opened the door for bariatric surgery to be performed on an outpatient basis, because this procedure does not open the digestive tract.72–74 Initial reports of outpatient laparoscopic Roux-en-Y procedures are being investigated for safety and appropriateness.75 The ability to sufficiently manage postoperative pain and address postoperative ambulation should be discussed preoperatively by the surgeon and anesthesia provider. The morbidly obese patient is at risk for persistent hypoxemia in the PACU, which may necessitate overnight supplemental oxygen therapy.
Morbid obesity is associated with an increased risk of obstructive sleep apnea (OSA).76 Preoperative airway evaluation (e.g., Mallampati classification, nuchal girth, redundant pharyngeal tissue) is important. A high Mallampati airway classification, reduced thyromental distance, and restricted mandibular mobility were predictive of difficult endotracheal intubation, yet an increasing BMI was not associated with difficulty.77 An assessment of intubating conditions in the patient with OSA found a 22% incidence of difficult endotracheal intubation.78 The likelihood of a difficult airway has to be assessed preoperatively, and the ability to manage the difficult airway has to be ensured.
If continuous positive airway pressure (CPAP) is part of the patient’s management of OSA, the patient, undergoing general anesthesia, should be instructed to bring his or her CPAP machine into the surgery center for use in the immediate postoperative recovery phase. Intraoperative benzodiazepine79 and opioid usage, out of concern for worsening airway obstruction, should be minimized or avoided in these patients, and pain should be controlled with alternative techniques (e.g., nonopioid analgesics, regional anesthesia techniques, local wound infiltration with local anesthesia) when possible.80 Moderate to severe OSA patients requiring postoperative opioids should not undergo ambulatory surgery.81
No increase in unanticipated hospitalizations has been shown in OSA patients who are deemed eligible to undergo ambulatory surgery.82,83 The decision concerning whether to provide for the patient with OSA in the ambulatory setting should be contingent on certain criteria being met. The Society for Ambulatory Anesthesia has recently released a consensus statement on preoperative selection of adult patients with OSA scheduled for ambulatory surgery. Patients with a known diagnosis of OSA and optimized comorbid medical conditions can be considered for ambulatory surgery if they are able to use a continuous positive airway pressure device in the postoperative period. Patients with a presumed diagnosis of OSA, based on screening tools such as the STOP-Bang questionnaire, with optimized comorbid conditions can be considered for ambulatory surgery if postoperative pain can be managed predominantly with nonopioid analgesic techniques. On the other hand, OSA patients with nonoptimized comorbid medical conditions may not be good candidates for ambulatory surgery. All obese patients should be assessed with the STOP-Bang questionnaire as part of the preoperative evaluation (see Box 43-2). A score greater than 3 indicates a high suspicion for OSA. As noted above, unless the patient’s comorbid conditions are optimized and they are able to use CPAP after discharge and achieve postoperative pain relief without opiates, they are not candidates for outpatient surgery (Box 37-2).84 Strict adherence to preoperative eligibility requirements and home care protocols is essential.85 Consideration should be given to scheduling these patients early in the day to allow for prolonged observation of an additional 3 hours prior to discharge.86 Patients with obstructive sleep apnea may be considered for discharge home if they are without (1) signs of moderate to severe OSA, (2) recurring PACU respiratory issues, that is, apnea, bradypnea, oxyhemoglobin desaturation, and (3) potent postoperative opioids for analgesia.87
Sickle Cell Disease
The possibility of sickle cell hemoglobinopathy should be considered in every African American when obtaining the preoperative medical history. If individual or family history is suggestive of the disease, a Sickledex may be obtained in children 6 months of age and older to determine the presence of sickle-shaped red blood cells.88 The patient with sickle cell disease is at risk for crisis development if acidosis, dehydration, or hypoxia occur. These patients often present for cholecystectomy because cholelithiasis is a well-recognized complication of chronic hemolysis.89
The select patient diagnosed with sickle cell disease is an acceptable outpatient candidate, but this patient is not without risk.90 Sickling of the red blood cells may occur when the patient with sickle cell trait is subjected to hypoxia.91 If the patient with sickle cell anemia is to be cared for in the ambulatory setting, certain criteria must be satisfied:
1. The patient should have no major organ disease as a result of the sickle cell disease.
2. The patient should not have had a sickle cell crisis for at least 1 year.
3. The patient should be compliant with the prescribed medical care.
4. On discharge, the patient should be within 15 minutes’ travel time to a facility prepared to care for the patient.
5. The patient should receive close follow-up postoperative care.
Unacceptable Patient Conditions for Ambulatory Surgery
Certain situations make ambulatory surgery impractical. Each patient must be considered individually for acceptability as an outpatient surgical candidate. Patients believed to be at increased risk for outpatient surgery and to be unacceptable candidates for such surgery are those with any of the following32:
• Unstable ASA physical status classification III or IV (e.g., cardiac, renal, endocrine, pulmonary, hepatic, or cancer diagnoses)
• Active substance/alcohol abuse
• Psychosocial difficulties, that is, responsible caregiver not available to observe the patient the evening of surgery (see Box 37-3)
• Morbid obesity with significant comorbid conditions, that is, angina, asthma, OSA
• Previously unevaluated and poorly managed moderate to severe OSA
• Ex-premature infants younger than 60 weeks postconceptual age requiring general anesthesia with endotracheal intubation
• Current sepsis or infectious disease necessitating separate isolation facilities
• Anticipated postoperative pain not expected to be controlled with oral analgesics or local anesthesia techniques
Patient Evaluation and Preparation
To recognize anesthetic risks and determine the patient’s suitability for the planned procedure, preoperative evaluation is mandatory for all patients preparing to undergo outpatient anesthesia and surgery. Challenges for the outpatient team will be organizing and accomplishing all the necessary tests and evaluations while causing the least inconvenience to the patient and maintaining an expedient surgical process. The preoperative interview elicits pertinent patient information and clarifies risk factors that may affect surgery and outcome. Additionally, by obtaining a thorough current and past medical history—including a personal and family anesthetic history—the staff may determine what further patient workup is required before surgery. A formalized preanesthesia assessment clinic is the most comprehensive and cost-effective process for preoperative evaluation and preparation.92 Preoperative screening also allows the staff to communicate what will be expected of the patient in the perioperative phases.
Consultations, laboratory tests, and diagnostic procedures should be performed based on clinical findings rather than on a preestablished regimen of “standard” tests. Without any discoveries from the medical history and physical examination, the probability of observing a significant abnormality is negligible in diagnostic procedures, including electrocardiogram, chest radiograph, and laboratory tests. Abnormal test results obtained from routine testing potentially alter patient care only 0.22% to 0.56% of the time.93 Routine preoperative laboratory screening is neither cost-effective nor predictive of postoperative complications.94–96
Patient Orientation
The preoperative interview allows the staff to convey what is expected of the patient and what the patient can expect perioperatively. Providing instructions to the patient, verbally and in writing, results in improved patient compliance. An information packet given to the patient at the interview is beneficial. It should detail specific instructions and concerns related to the procedure (Box 37-4).
History and Physical
Such a review may be accomplished in a written format and would include a general review of the major systems, history of allergies, current medications, past and present medical problems, laboratory and diagnostic test results, and patient and family response to previous anesthetics. Prior anesthesia records should be examined for complications, response to anesthesia, and postoperative course. Patient evaluation should be conducted within 30 days of the scheduled surgery for medically stable patients and within 72 hours of the scheduled surgery for high-risk patients. The clinician should determine whether any changes might have occurred since the original history and physical examination were performed, and an update note should be made on the day of the procedure. A review of current vital signs, laboratory test results, diagnostic reports, and fasting status should be made.
Laboratory Evaluation
Each ambulatory center should have a consensus regarding the minimum testing requirement for surgery. These testing criteria depend on the proposed surgical procedure, the patient’s medication history, and the patient’s physical condition. Some states and regions have established minimum testing requirements. However, conducting a battery of preoperative laboratory tests without specific indications that they are needed has not been shown to reduce patient morbidity,94 is not cost effective, and may even place the patient at increased risk.95 Discriminating laboratory testing, based on findings from the history and physical examination and primarily designed to evaluate a patient’s comorbidities and surgical risk, seems to be indicated. Normal laboratory test and diagnostic procedure results are deemed current if the tests are performed within 6 months of surgery if the patient’s physical condition remains stable.96,97 Exceptions include serum potassium level determinations, which should be obtained within 7 days of surgery for patients receiving diuretics or digitalis, and blood glucose level determinations, which should be obtained on the same day of surgery for patients with diabetes controlled by medication. Physical conditions and systemic illnesses in which preoperative laboratory testing is appropriate are listed in Box 37-5.
BOX 37-5 Indications for Laboratory Testing
Platelet Count and Bleeding Time
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Obesity and Anesthesia Practice
Renal Anatomy, Physiology, Pathophysiology, and Anesthesia Management
Positioning for Anesthesia and Surgery
Musculoskeletal System Anatomy, Physiology, Pathophysiology, and Anesthesia Management
Regional Anesthesia: Upper and Lower Extremity Blocks
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