Discharge Criteria and Complications After Ambulatory Surgery

Abstract

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 up to 3 days postoperatively, when testing can reveal cognitive defects in GA patients that are not present in patients who received local anesthetic infiltration [34]. There have been no trials comparing regional blocks with the new, less soluble volatile anesthetics, which have more rapid recovery profiles. Patients who have had a peripheral nerve block need not be detained until full return of sensation if discharge criteria have been achieved. It is acceptable to send a patient home with an anesthetized limb properly protected, with careful written and verbal instructions, and with a 24-h contact telephone number [35]. Spinal anesthesia is a simple and reliable technique that has been widely used for ambulatory anesthesia [36]. Because of its short action, lidocaine has been commonly used for ambulatory procedures. However, there has been concern over possible neurotoxic effects of the 5% hyperbaric solution of lidocaine, with numerous reports of transient radicular irritation (TRI) after its use in spinal anesthesia [37,38]. Recently, even the 2% solution has been associated with an increased incidence of TRI [39]. Investigators have therefore been experimenting with more dilute isobaric solutions of lidocaine. One study has indicated that 40 mg of lidocaine (as a 1% solution) provided reliable anesthesia for outpatient knee arthroscopies, with a mean discharge time of 178 min [40]. Smaller doses provided inadequate anesthesia, whereas larger doses led to longer recovery times. With the continuing controversy over the use of lidocaine for spinal anesthesia, other avenues are being explored to achieve reliable spinal anesthesia with rapid recovery and minimal adverse effects. Ben-David et al. [41] demonstrated that small doses of dilute bupivacaine (7.5 mg/0.25%) provide reliable anesthesia for knee arthroscopies, with a mean time to discharge of 202 min. Vaghadia et al. [42] showed that a combination of 25 mg of lidocaine and 25 [micro sign]g of fentanyl produces sufficient anesthesia for brief laparoscopic procedures, with patients meeting discharge criteria at 122 min. One factor limiting the popularity of outpatient spinal anesthesia among anesthesiologists is postdural puncture headache (PDPH) [43-46]. It seems that 25-gauge pencil-point needles produce an incidence of PDPH <1%, and the headaches that occurred were mild and self-limited [43]. Fine needles (29 gauge) must be used to achieve similarly low headache rates with Quincke point needles. However, the use of fine needles greatly increases the technical difficulty of dural puncture and leads to a higher failure rate [47]. Before allowing patients to ambulate after spinal anesthesia, it is important to ensure that the motor, sensory, and sympathetic blocks have regressed. Suitable criteria to judge when this has occurred include normal perianal (S4-5) sensation, plantar flexion of the foot, and proprioception in the big toe [48]. The major advantages of spinal anesthesia are the same as those of other forms of regional anesthesia. Wound pain after spinal anesthesia can be less intense and shorter lived than that after GA [49]. Malignant Hyperthermia In the past, overnight hospitalization of patients with suspected or confirmed malignant hyperthermia (MH) was common practice. A large, retrospective review of 285 children with suspected or proven MH susceptibility was conducted at Toronto's Hospital for Sick Children [50]. There were no MH reactions in these patients, all of whom had been given trigger-free anesthetics. The authors concluded that same-day discharge is safe for patients with suspected or biopsy-proven MH after uncomplicated ambulatory surgery. Complications of Ambulatory Anesthesia The overall safety record of modern ambulatory anesthesia is impressive [51-53], with major morbidity and mortality being extremely rare [54]. A major study of 38,958 patients after ambulatory surgery found that the risk of dying in the 30 days after surgery was 1:11,273. The incidence of myocardial infarction, stroke, and pulmonary emboli was extremely low, lower than would be expected among a similar age group who had not undergone ambulatory surgery [54]. However, minor sequlae are relatively common and may lead to delays in discharge, unanticipated admission, and returns to the hospital. The unanticipated postoperative admission rate from the ASU is an important outcome measurement; in most centers, it averages 1% [55]. In practice, the most common causes for admission are surgical factors, particularly In the 30 days after ambulatory surgery, of patients will contact a or the services complications the most common of which is surgical pain is also an important factor at this One found that of patients had to contact their or the hospital because of inadequate and 1% with the ambulatory surgical experience because of inadequate analgesia after discharge pain is the most commonly of ambulatory anesthesia (Figure with up 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 postoperatively, pain at and were the postoperative and of patients from dizziness, and Reprinted from Chung F. Recovery pattern and home readiness after ambulatory surgery. Anesth Analg large, study observed patients to identify factors for postoperative pain and urological procedures were related to pain, as was the of anesthesia, with patients who underwent longer procedures more It was also confirmed that patients with pain stayed significantly longer in the PACU and ASU. pain can be an important of and pain can nausea These that close should be to analgesia in ambulatory surgical patients in the early postoperative period. ambulatory procedures, such as shoulder may require given for surgery does not delay discharge, nor does it the incidence of nausea and vomiting, compared with similar doses in the fentanyl can be used in the PACU and seems to produce a lower incidence of However, the of analgesia in the ASU is not as and oral must be given early The addition of local anesthetics or can improve postoperative an earlier discharge. analgesia intraoperative local anesthesia, and has been to as either or analgesia The combined can lead to significantly shorter discharge lower pain and a lower incidence of nausea and vomiting, compared with traditional anesthetic techniques In light of these recent a can be made for analgesia as the technique of for ambulatory surgery. and is of ambulatory anesthesia that may lead to discharge and unanticipated However, its incidence seems to be as a result of newer and anesthetic techniques is not only to the it can delay discharge It has been that nausea can the patient for an ambulatory treatment by approximately The incidence of may not be apparent in the as it may not until patients are discharged and more at home. to of patients experience at home after discharge, many of whom not experience symptoms in the PACU can be to the rate of with its rapid recovery is the most commonly used anesthetic for ambulatory procedures and its use is associated with less nausea and vomiting than other It has been suggested that propofol has a distinct However, three trials have to demonstrate the effects of propofol The of in to is studies have to a reduction in the incidence of nausea and vomiting when is from the anesthetic However, of trials on the have all a reduction in the incidence of when was One of these studies found a significantly higher incidence of when was a that may the of it from ambulatory anesthetic The muscle to have on recovery in their but the use of may be associated with an increased incidence of when used as a because of its effects The rapid recovery of and to be from the anesthetic the incidence of The have a action and one effective of the incidence of is to their use Because the incidence of is relatively low and many of the available have routine cannot be However, of patients at high risk of can be and are indicated for these outpatients include those with a history of or undergoing procedures, and children undergoing surgery. The has and it is an effective if given at the end of surgery However, two trials have demonstrated that it is no more effective than mg has been to be more than 10 mg in are being investigated One study has demonstrated that is more effective than in Another has that which has effective in is more effective than in in ambulatory patients who have undergone laparoscopic surgery One factor that has been in the of is after by personnel and it has also been suggested that may the incidence of However, one group investigated this and found that with a had no on the incidence of in the it may have even increased after discharge Complications complications, such as dizziness, and have been after ambulatory surgery (Figure These have not been investigated as extensively as pain and but they may, in be or at perioperative The relatively simple measure of giving patients 2 of can the incidence of dizziness, and for up to h dizziness, and may also delay patients from normal The and of postoperative symptoms was in ambulatory patients Patients who more postoperative symptoms had lower functional when assessed on a pain was associated with the decrease in postoperative functional but dizziness, and were also It is apparent that these symptoms have received relatively although they can have a on patients' ability to their normal and The and safety of an ambulatory surgery on patients' and Patients verbal or them for many years, written have been Given the of it was that these would their way into patient have been to patients Although those who the that they found it their knowledge the perioperative was not than those who had not it Although these may some for the for the written must still be the effects of and patients have been advised drinking for h after With the of patients may be able to drink safely after ambulatory surgery. it is to patients not to after anesthesia because residual psychomotor impairment driving that patients should not for h after an anesthetic of h and should not for h after an anesthetic of h [1]. However, these are based on studies using and with the of this must be to provide patients with The of the of in the ambulatory surgery setting is the patient. In outpatients have been with their experience of ambulatory anesthesia and surgery In a recent study, patients completed a and only were with the overall Although only with anesthesia, this was a of with ambulatory surgery The most common for inadequate between the patient and the staff. with anesthesia was also related to the number of postoperative symptoms Ambulatory anesthesia is a major part of the must ensure that the number of ambulatory patients are discharged into the home Removing drinking and voiding from discharge criteria may to speed discharge. ambulatory patients and bypassing the PACU may more efficient, but with patients being and discharged so we have a responsibility to be of such as pain, and that occur at home after discharge. These can delay a patient's return to full function and leave a of ambulatory surgery.