Discharge Criteria and Complications After Ambulatory Surgery

Section Editor: Paul F. White. In recent years, the emphasis in providing surgical services has undergone remarkable change. Previously, patients undergoing surgical procedures remained in a hospital for many days after the operation. In 1994, 66% of all elective operations in the United States were performed on an outpatient basis [1]. More complex ambulatory procedures are being performed on sicker patients [2]. With the increased emphasis on early discharge after surgery and anesthesia, it is important to identify criteria that can be used to determine when patients can safely go home under the care of a friend or relative. In this article, we review current knowledge regarding the assessment of home-readiness after ambulatory surgery and discuss potential complications and appropriate treatment regimens. Defining Recovery Recovery is a continual process, the early stages of which overlap the end of intraoperative care. Patients cannot be considered fully recovered until they have returned to their preoperative physiological state. This entire process may last many days, but it can be conveniently divided into three distinct phases (Table 1) [3].Table 1: Stages of RecoveryEarly recovery (Phase I) lasts from discontinuation of anesthesia until patients have recovered their protective reflexes and motor function. Because they require close monitoring and supervision during this stage, it normally takes place in the high-dependency atmosphere of the postanesthesia care unit (PACU) with suitably trained nursing staff. In deciding when patients have recovered enough to allow their safe transfer to an ambulatory surgical unit (ASU), or Phase II recovery, the Aldrete scoring system may be used [4]. First described in 1970, and although not originally designed for ambulatory patients, it is still widely used in many PACU's in its original form. This system assigns a score of 0, 1, or 2 to activity, respiration, circulation, consciousness, and color, giving a maximal score of 10. A score of 9 indicates recovery sufficient for the patient to be transferred from the high-dependency PACU to the ASU. However, with the advent of pulse oximetry, a more reliable indicator of oxygenation than clinical observation, a modification of the Aldrete score has been suggested (Table 2) [5]. In this version, the need for room air O2 saturation is >92%. After patients were discharged, they underwent full recovery at home (Phase III recovery).Table 2: The Modified Aldrete Scoring System for Determining when Patients Are Ready for Discharge from the Postanesthesia Care UnitFast-Tracking With newer anesthetics and techniques that allow more rapid awakening, it has been suggested that early recovery may be completed in the operating room (OR). Patients are transferred directly to the ASU, bypassing the PACU [6,7]. In patients undergoing outpatient laparoscopic tubal ligation maintained with desflurane or sevoflurane, Aldrete scores of 10 were achieved significantly faster than in those maintained with propofol [6]. These investigators also demonstrated that 90% of the patients anesthetized with desflurane were fast-track-eligible on arrival in the PACU [6]. Apfelbaum et al. [8] evaluated bypassing PACU at five surgical sites. Anesthesiologists were instructed to assess all ambulatory surgical patients for recovery while still in the OR, using standardized discharge criteria typically used at the end of a PACU stay. The PACU bypass rate for patients who received general anesthesia (GA) varied from 13.9% to 42.1%. The cost of maintaining personnel constitutes the major expense in PACU time [6,9]. Therefore, because fast-tracking reduces PACU activity, the reduction in staffing requirements could result in potential cost-savings. Further research in this area is needed before implementing the fast-tracking concept safely and efficiently. Once patients have been transferred from the OR to the ASU, they should stay there until intermediate recovery is complete (i.e., coordinated, ambulating, and judged to be home-ready). For an ASU to be effective and efficient, it is important that patients not be detained unnecessarily once intermediate recovery is complete. However, premature discharge may lead not only to the possibility of patients suffering complications, but to readmission and medicolegal concerns. Although patients may have been discharged from the hospital, they cannot be considered fully recovered until they have returned to their preoperative physiological and functional state. Discharge Criteria It is the physician's responsibility to ensure that a patient is sufficiently recovered to leave the ASU under the appropriate care of a relative or other caregiver. Legal action may ensue if a patient who is discharged prematurely or inadequately supervised comes to harm as a result of residual psychomotor impairment [10]. However, "a written policy establishing specific discharge criteria is a sound basis for a legally sufficient discharge decision" [11]. Thus, the ASU nursing staff may discharge patients who meet specific written criteria. The key question is what criteria we should use to determine the home-readiness of a patient. Psychomotor Tests There have been many attempts to produce a simple reproducible test to assess a patient's recovery from anesthesia. Many of the psychomotor performance tests used in other fields and were adapted for evaluating the postanesthesia period. In 1969, a modified Gestalt test-the Trieger dot test-was proposed to measure recovery [12]. In this test, patients are asked to connect a series of dots to form a pattern. The number of dots missed in the line drawn represents the score. These scores improve as patients recover from anesthesia. The Trieger dot test is only one of a battery of psychomotor tests that measure recovery from anesthesia. The Maddox wing (a device to test extraocular muscle balance) [13], driving simulators [14], reaction time tests, and peg board tests [15] have all been used. The flicker fusion threshold [16], which measures the frequency at which the patient perceives a flashing light to be continuous, has been used. So also have perceptual speed tests [17] and the digit symbol substitution test [18]. Recently, a complex test assessing patients' balance by standing them on a dual forceplate has been suggested [19]. Despite the number and variety of tests in use, none has been specifically validated by follow-up studies providing adequate criteria to guide discharge in the ambulatory setting. Many are complex and time-consuming, and they may also require special equipment that is not readily available. Many of these tests also suffer from a major drawback: they assess recovery of one part of brain function only, rather than complete recovery of the patient. Patients may be able to complete paper and pencil tests, yet still be in pain or nauseated. Not surprisingly, these tests have not found their way into routine clinical practice. Most centers still rely on clinical criteria for practical discharge decisions. The more complex psychomotor tests, however, are still useful research tools, because they are sensitive to the degree of impaired psychomotor function [20]. Table 3 summarizes widely accepted clinical criteria for safe discharge from the hospital [1].Table 3: Guidelines for Safe Discharge After Ambulatory SurgeryA Clinical Scoring System Anesthesiologists experienced in outpatient anesthesia can use their knowledge and experience to decide when a patient has recovered sufficiently for discharge. However, if physicians are to delegate the process, then a well designed clinical scoring system will provide a reliable guide [21]. Using the Postanesthesia Discharge Scoring System (PADS) [22] (Table 4), most patients can be discharged within 2 h after surgery [23] (Figure 1). The PADS scoring system was developed by Chung et al. at the Toronto hospital, where it has been used extensively to determine when patients can be discharged home safely.Table 4: Postanesthesia Discharge Scoring System (PADS) for Determining Home-ReadinessFigure 1: Most patients had recovered from anesthesia and were discharged home within 1-2 h after surgery. Only 4% of patients were discharged home 3 h after surgery. Reprinted from Chung F. Recovery pattern and home readiness after ambulatory surgery. Anesth Analg 1995;80:896-902.An earlier version of PADS and the clinical criteria in Table 3 both require that patients have either taken oral fluids or passed urine before being allowed home. Much recent scrutiny of the ambulatory discharge process has centered on these two factors. Are drinking and voiding before discharge fundamental to patient safety, or do they merely delay the release of patients who are already adequately recovered? Is the Ability to Tolerate Oral Fluids Necessary? Although it is obviously unacceptable to discharge a patient who is actively vomiting, is it necessary to insist that those patients who feel unable to tolerate oral fluids demonstrate that they can do so before discharge? One study addressed this question [24]. Nine hundred eighty-nine children were randomly assigned to two treatment groups. One group of "mandatory drinkers" had to fulfill the traditional discharge criteria by demonstrating the ability to drink clear fluids without vomiting. The other group were "elective drinkers" and were allowed, but not required, to drink. The mandatory drinkers had a higher incidence of nausea in the ASU and stayed there longer. No patient in either group required readmission for persistent vomiting. Since completion of this study, the Children's Hospital of Philadelphia has discharged >6000 ambulatory surgery patients without requiring them to drink before discharge. Three children required admission for vomiting, and only one was readmitted for intractable vomiting and dehydration [24]. Another study involving 726 adult patients showed that there was no difference in the incidence of postoperative nausea and vomiting (PONV) between the drinking and nondrinking groups [25]. Eliminating drinking can slightly shorten the stay in the ASU without evidence of adverse effects. Therefore, medical staff and nurses should be taught that drinking may not be necessary before discharge for adult ambulatory surgical patients, and the discharge criterion could be modified accordingly. Is Voiding Necessary Before Discharge? Insisting that patients pass urine can lead to delays in discharge. There is evidence that outpatients not at high risk of urinary retention can be safely discharged before they have voided without urinary retention problems at home [26]. Risk factors for postoperative urinary retention include a history of postoperative urinary retention, spinal/epidural anesthesia, pelvic or urological surgery, and perioperative catheterization [26]. One study observed 1719 consecutive ambulatory patients, 30 of whom were identified as being ready for discharge, unable to void, and in a high-risk group for urinary retention. These patients were discharged from the ASU and were followed-up by a home healthcare nurse. Of these 30 patients, only 3 required catheterization at home, and all those who needed catheterization had undergone a rectal or inguinal procedure under spinal anesthesia [26]. This suggests that even patients at high risk of urinary retention can be discharged before they have voided, given appropriate follow-up, which can include catheterization by homecare nurses. The cost of providing homecare nurses may, however, outweigh any savings from discharging these patients early. Another study investigated the effects of adding 10 [micro sign]g of fentanyl to 5 mg of bupivacaine intrathecally for ambulatory knee arthroscopies and found that neither time to urination nor time to discharge were prolonged by the addition of fentanyl [27]. Given the relatively small sample size, additional studies are needed before a final recommendation can be made on whether ambulatory patients receiving intrathecal opiates can be discharged before voiding. These studies were all performed on adults, and it may not be possible to extrapolate these data to children. Removing the requirement to drink and void and separating the pain and nausea/vomiting scores have produced the current version of PADS [28] (Table 4). The PADS is based on five criteria: vital signs, ambulation, nausea/vomiting, pain, and surgical bleeding. Each of these items is assessed independently and assigned a numerical score of 0-2, with a maximal score of 10. Patients are judged fit for discharge when their score is >9. For surgical procedures in which voiding is not a discharge criterion, patients are advised to contact the responsible and available physician if they are unable to void within 6-8 h after discharge. Most patients can be discharged within 1-2 h after surgery [23]. Delays in discharge are related to persistent symptoms such as pain, nausea/vomiting, hypotension, dizziness, unsteady gait, syncope, and asthma. Delays can also occur when an escort is not immediately available [23]. Although 50,000 patients have been discharged safely from the Toronto Hospital using PADS, it has yet to be validated by other researchers. Discharge After Regional Anesthesia Patients undergoing regional anesthesia should expect the same standard of postoperative care as those who have undergone GA [29]. However, regional anesthesia does bring unique advantages and problems to the ambulatory setting [30]. For example, some authors have demonstrated significantly faster discharges after regional techniques [29]. One study comparing three-in-one femoral block with GA for knee arthroscopy found that the block patients could be discharged approximately 40 min earlier than the GA patients [31]. Interscalene block can provide good analgesia after shoulder arthroscopy and can also decrease the incidence of nausea and vomiting and of unexpected hospital admissions, compared with GA [32]. Even when combined with GA, a suprascapular block can improve recovery profiles and facilitate early discharge after arthroscopic shoulder surgery [33]. The benefits of avoiding GA may be apparent to 3 days when can in GA patients that are not in patients who received There have been no comparing regional with the which have more rapid recovery Patients who have had a block need not be detained until full of if discharge criteria have been It is to a patient home with an anesthetized with written and and with a contact number anesthesia is a simple and reliable that has been widely used for ambulatory anesthesia Because of its has been used for ambulatory However, there has been possible effects of the of with of after its use in spinal anesthesia Recently, even the has been with an increased incidence of have been with more of One study has that 40 mg of a reliable anesthesia for outpatient knee with a discharge time of min anesthesia, to recovery With the the use of for spinal anesthesia, other are being to reliable spinal anesthesia with rapid recovery and adverse effects. et al. demonstrated that small of bupivacaine provide reliable anesthesia for knee with a time to discharge of et al. showed that a of mg of and [micro sign]g of fentanyl sufficient anesthesia for laparoscopic with patients discharge criteria at One the of outpatient spinal anesthesia is It that produce an incidence of and the that were and be used to with However, the use of the of and to a higher rate Before patients to after spinal anesthesia, it is important to ensure that the and have criteria to when this has include of the and in the The major advantages of spinal anesthesia are the same as those of other of regional anesthesia. pain after spinal anesthesia can be and than that after GA In the of patients with or was practice. A review of children with or was at Hospital for There were no in these patients, all of whom had been given The authors that discharge is safe for patients with or after ambulatory surgery. of Ambulatory Anesthesia The of ambulatory anesthesia is with major and being A major study of patients after ambulatory surgery found that the risk of in the 30 days after surgery was The incidence of and was than be a group who had not undergone ambulatory surgery However, are relatively and may lead to delays in discharge, and to the The postoperative admission rate from the ASU is an important in most it In the most for admission are surgical In the 30 days after ambulatory surgery, of patients will contact a or the services complications the most of which is surgical pain is also an important at this One found that of patients had to contact their or the hospital because of and with the ambulatory surgical experience because of analgesia after discharge pain is the most of ambulatory anesthesia (Figure with to of patients pain h after and general surgery of pain in the ambulatory surgical patient is pain treatment can delay discharge and is However, the use of opiates can lead to postoperative nausea and vomiting 2: h pain at and were the postoperative and of patients from dizziness, and Reprinted from Chung F. Recovery pattern and home readiness after ambulatory surgery. 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