A Comparison of Spinal, Epidural, and General Anesthesia for Outpatient Knee Arthroscopy

AMBULATORY ANESTHESIA SECTION EDITOR PAUL F. WHITE SOCIETY FOR AMBULATORY ANESTHESIA A Comparison of Spinal, Epidural, and General Anesthesia for Outpatient Knee Arthroscopy Michael F. Mulroy, MD, Kathleen L. Larkin, MD, Peter S. Hodgson, MD, James D. Helman, MD, Julia E. Pollock, MD, and Spencer S. Liu, MD Department of Anesthesiology, Virginia Mason Medical Center, Seattle Washington We compared general, epidural, and spinal anesthesia for outpatient knee arthroscopy (excluding anterior cruciate ligament repairs). Forty-eight patients (ASA physical status I III) were randomized to receive either propofol-nitrous oxide general anesthesia with a laryngeal mask airway with anesthetic depth titrated to a bispectral index level of 40 60, 15 20 ml of 3% 2-chloroprocaine epidural, or 75 mg of subarachnoid procaine with 20 g fentanyl. All patients were premedicated with 0.035 mg/kg midazolam and 1 g/kg fentanyl and received intraarticular bupivacaine and 15 30 mg of IV ketorolac during the procedure. Recovery times, operating room turnover times, and patient satisfaction were recorded by an observer using an objective scale for recovery assessment and a verbal rating scale for satisfaction. Statistical analysis was performed with analysis of variance and 2. Postanesthesia care unit discharge times for the general and epidural groups were similar (general 104 31 min, epidural 92 18 min), whereas the spinal group had a longer recovery time (146 52 min) (P 0.0003). Patient satisfaction was equally good in all three groups (P 0.34). Room turnover times did not differ among groups (P 0.16). There were no anesthetic failures or serious adverse events in any group. Pruritus was more frequent in the spinal group (7 of 16 required treatment) than in the general or epidural groups (no pruritus) (P 0.001). We conclude that epidural anesthesia with 2-chloroprocaine provides comparable recovery and discharge times to general anesthesia provided with propofol and nitrous oxide. Spinal anesthesia with procaine and fentanyl is an effective alternative and is associated with a longer discharge time and increased side effects. (Anesth Analg 2000;91:860 4) Outpatient arthroscopic knee surgery can be performed with general or regional anesthesia. Epidural anesthesia (1) and peripheral nerve block (2) have both provided more rapid discharge than general anesthesia in previous reports, whereas spinal anesthesia with bupivacaine (3) has also been shown to provide discharge times comparable to general anesthesia. Recent data, however, suggest that spinal and epidural anesthesia require longer discharge times than the newer shorter-acting general anesthetic drugs (propofol and sevoflurane) (4,5). Published reports have not compared optimal techniques in each category. We hypothesized that the ideal selection of local anesthetic drugs for either epidural or spinal anesthesia would provide recovery times comparable to those obtained with short-acting general anesthesia and result in equal patient satisfaction. We compared Accepted for publication May 17, 2000. Address correspondence and requests for reprints to Michael F. Mulroy, MD, Department of Anesthesiology, B2-AN, 1100 Ninth Ave., PO Box 900, Seattle, WA 98111. Address e-mail to anemfm @vmmc.org. discharge times, side effects, operating room (OR) efficiency, and patient satisfaction levels of three anesthetic techniques, each performed with an ideal drug, for outpatient arthroscopy in a prospective, randomized fashion. Methods After institutional review board approval, patients scheduled for elective outpatient unilateral knee arthroscopy, not including anterior cruciate ligament repair, were asked to participate in a prospective, randomized comparison of anesthetic techniques. All patients were between 21 and 60 yr of age, ASA physical status I III, and 110 kg. Patients were English speaking, available for follow-up phone interviews, and had no medical contraindication to any of the three anesthetic techniques (allergy, bleeding disorders, localized infection, neurologic disease). After informed consent, patients were randomized by sealed envelopes to receive either general, epidural, or spinal anesthesia. All patients were premedicated with a 2000 by the International Anesthesia Research Society 860 Anesth Analg 2000;91:860 4 0003-2999/00

ANESTH ANALG AMBULATORY ANESTHESIA MULROY ET AL. 861 2000;91:860 4 ANESTHESIA FOR KNEE ARTHROSCOPY maximum of IV 0.035 mg/kg midazolam and 1 g/kg fentanyl. General anesthesia was performed with 2 mg/kg IV propofol induction and 60% nitrous oxide by laryngeal mask airway with a continuous infusion of propofol titrated to maintain the bispectral index monitor reading between 40 and 60. The infusion was discontinued when the trocars were removed from the knee. Epidural anesthesia was performed in a standard fashion at the L2-3 or L3-4 interspace with the operative knee in the dependent position. Skin infiltration was performed with 1% lidocaine, and a test dose of 3 ml of 1.5% lidocaine with 15 g epinephrine was injected. If there was no evidence of IV or subarachnoid injection, 15 ml of 3% 2-chloroprocaine was injected in 5 ml increments, with an additional 5 ml added after 10 min, if the block height was below T-10 (level needed to provide anesthesia for thigh tourniquet discomfort). Spinal anesthesia was performed at the L2-3 or L3-4 interspace with a 25-gauge Whitacre needle with the operative knee dependent. After free flow of cerebrospinal fluid, 75 mg of procaine plus 10 20 g of fentanyl diluted with an equal volume of cerebrospinal fluid was injected, and the patient turned supine. Patients receiving spinal or epidural anesthesia who requested sedation were given an intraoperative infusion of propofol (25 50 g kg 1 min 1 ). All patients received 15 30 mg IV ketorolac. The surgeon injected 50 ml of 0.25% bupivacaine into the knee joint at the completion of the procedure. When the surgical procedure was performed by the same surgeon sequentially in the same OR, turnover time was measured. This was defined as the time interval from the departure of the previous patient from the OR until the completion of anesthesia preparation. All patients were transferred by stretcher to the Phase I postanesthesia care unit (PACU). When vital signs were stable for two measurements and block level (for regional block patients) was below T-8, they were transferred to the Phase II area. Discharge time was recorded as the time from admission to PACU until the patient met all discharge criteria from Phase II. These included mental alertness, stable vital signs, absence of nausea, control of pain, ability to ambulate, and (for regional techniques) voiding. Side effects measured were the incidence of hypotension (systolic blood pressure 100 mm Hg requiring treatment with ephedrine at the discretion of the anesthesiologist) or bradycardia (heart rate 60 requiring treatment with atropine at the discretion of the anesthesiologist) in either the OR or in the PACU, nausea or vomiting, pain severe enough to require IV narcotics in the PACU, or pruritus requiring treatment. Patient satisfaction (rated on a verbal scale of 5 very satisfied, 4 satisfied, 3 neutral, 2 dissatisfied, 1 very dissatisfied) and specific side effects were evaluated by follow-up phone call 24 h after the procedure. For data analysis, discharge time was considered the primary outcome variable, with a difference considered significant at the P 0.05 level. The secondary variable was the efficiency, as estimated by the room turnover time. These were compared by analysis of variance for the three groups and confirmed with Wilcoxon s nonparametric test. The frequency of side effects among the groups was compared by 2 analysis with Fisher s exact test. A power analysis indicated that a sample size of 16 patients per group was required to show a 45 min difference in discharge time among groups at the P 0.05 level with 80% power. This was based on a similar study of procaine spinal anesthesia for knee arthroscopy performed in the same outpatient unit with a standard deviation of 47 min for discharge time (6). Results Between March 25, 1999, and December 21, 1999, we recruited 192 patients to participate. One hundred forty-one patients refused randomization (95 requesting regional anesthesia and 46 preferring general anesthesia); 51 patients accepted randomization. There were no differences in age, weight, sex, ASA physical status, midazolam administration, or fentanyl administration among groups (Table 1). Three were excluded from analysis (one overnight admission, two protocol violations). All operations were performed by one of three surgeons. There were no major surgical or anesthetic complications. Anesthesia was satisfactory for incision in all three groups; one patient in the epidural group was given an intraoperative bolus of propofol at the request of the surgeon to provide greater muscle relaxation. Four of 16 epidurals were redosed during the case. Of 32 patients receiving regional anesthesia, 13 were given propofol infusions for sedation (9 epidural, 4 spinal). In the PACU, nine patients required IV narcotics for pain (five general, two epidural, two spinal). Antiemetics were necessary for three spinal patients. Sedation was reported as prolonging Phase I stay in one patient in the general group. Antipruritics were given to seven patients, all in the spinal group (P 0.001). Voiding was required for discharge after regional anesthesia. Time from injection to voiding was shorter in the epidural group versus the spinal group (144 22 vs 193 50 min, P 0.0013). The time in the PACU was also significantly shorter for general and epidural as compared with spinal (general, 104 31 min; epidural, 92 18 min; spinal, 146 52 min; P 0.0003 with Scheffé s adjusted P value of 0.008 for general versus spinal and 0.0006 for epidural versus spinal) (Table 2).

862 AMBULATORY ANESTHESIA MULROY ET AL. ANESTH ANALG ANESTHESIA FOR KNEE ARTHROSCOPY 2000;91:860 4 Table 1. Demographic Data General Epidural Spinal Age (yr) a 42 14 42 13 46 13 Weight (kg) a 83 15 79 14 82 16 Male (%) 56 69 63 ASA physical status 12/4/0 12/3/1 15/1/0 (I/II/III) Midazolam (mg) a 1.7 0.7 2.4 1.5 2.2 1.0 Fentanyl ( g) a 71.6 28.7 55.5 33.8 36.3 41.1 Operative time (min) a 32 17 27 11 31 11 a Average sd. In follow-up evaluation, 44 of 48 patients were satisfied with the care they received. (Table 2) Four patients complained of mild/moderate backache on follow-up phone call (3 epidural, 1 spinal). No patients had backache immediately after block resolution or back pain radiating to the legs (transient neurologic symptoms [TNS]) after discharge. One patient in the spinal group had a positional headache which did not require treatment. Minor side effects were infrequent (Table 2). A total of 42 patients said they would choose the same anesthetic again; three general anesthesia patients said they would not because they would want to watch the procedure. Discussion General and regional anesthesia techniques have been used for outpatient knee arthroscopy. To date, however, there has not been a direct comparison of the new general anesthetics to ideal regional anesthetic techniques. Parnass et al. (1) used isoflurane for general anesthesia, rather than the newer short-acting anesthetics. New general anesthetics including propofol, desflurane, and sevoflurane allow for faster emergence after general anesthesia than thiopental and isoflurane, and the potential for earlier discharge in the outpatient setting. Pavlin et al. (4) reported that general anesthesia with these drugs allowed an earlier discharge compared with spinal and epidural anesthesia in her practice (184 vs 202 minutes for men, 185 vs 213 minutes for women), but she did not specifically study knee arthroscopy, nor the use of short duration neuraxial regional anesthesia techniques. Luttropp et al. (5) reported that for knee arthroscopy, general anesthesia with either propofol or sevoflurane provides faster recovery than spinal anesthesia (116 and 141 vs 176 minutes), although with a higher frequency of postoperative nausea and vomiting with sevoflurane. Regional anesthesia has been used successfully for outpatient knee arthroscopy. Peripheral nerve block of the lumbar plexus block at the groin provides satisfactory anesthesia and rapid discharge (2,7), as is consistent with other comparisons of peripheral nerve blocks to general anesthesia (4). Peripheral nerve blocks, however, may take longer to perform, be less familiar to the practitioner, have a higher failure rate (7), and may have a slow onset of anesthesia (8). Neuraxial blocks are simpler to perform and are used more often in the outpatient setting. Epidural anesthesia allows the titration of short duration local anesthetics to provide potentially rapid discharge. Parnass et al. (1) demonstrated faster discharge with lidocaine epidural anesthesia than general anesthesia with isoflurane (159 vs 208 minutes). Dahl et al. (9) compared general anesthesia with propofol to spinal and epidural anesthesia, but did not report actual discharge times and used the longer-acting mepivacaine to provide epidural anesthesia. Epidural anesthesia with chloroprocaine provides faster resolution compared with lidocaine (127 vs 195 minutes) (10), and may be a superior choice. Although back pain has been reported with this drug, it appears to be related to the use of large doses (11), and may not be a problem when doses of 25 ml or less are used. Thus, epidural anesthesia with chloroprocaine may offer the current optimal clinical practice for knee arthroscopy. Spinal anesthesia is also advocated for outpatient surgery because of its reliability and simplicity, but suffers the limitation of a single injection technique. Larger doses may be required for adequate anesthesia, but may be associated with longer duration of action. Luttropp et al. s (5) relatively large dose of spinal anesthesia with 70 80 mg of lidocaine may account for longer discharge time compared with general anesthesia. Selection of an optimal drug and dose is problematic because of a dearth of comparative studies. Lidocaine has been the traditional short-acting spinal anesthetic. Small-dose (40 mg) subarachnoid lidocaine provides discharge times equivalent to epidural chloroprocaine (12), but with a 10% failure rate. Reports of TNS after use of lidocaine for lithotomy and arthroscopy procedures have led to a search for alternative spinal anesthetics (13). Ben-David et al. (14) found that 5 mg bupivacaine with 10 g of fentanyl avoided TNS and provided satisfactory anesthesia for knee surgery, but with discharge times comparable to reports of duration of spinal anesthesia with 50 mg lidocaine (15,16). Procaine has been regarded as a shorter-acting spinal anesthetic, and has been studied recently as an alternative to lidocaine. Hodgson and Liu (6) reported that subarachnoid 100 mg hyperbaric procaine is associated with less TNS, but a higher failure rate and longer discharge time than 50 mg lidocaine. Axelrod et al. (17) have reported shorter recovery times with doses of 60 and 80 mg procaine when fentanyl is added, but block heights below T-10 with the 60 mg dose. From these data, we estimated that a 75 mg dose of procaine with fentanyl might provide less risk of TNS and the best chance of a

ANESTH ANALG AMBULATORY ANESTHESIA MULROY ET AL. 863 2000;91:860 4 ANESTHESIA FOR KNEE ARTHROSCOPY Table 2. Results General Epidural Spinal Turnover time (min) a 24 6(n 8) 23 6(n 5) 28 9(n 3) Time to void b (min) a NA 80 16* 135 51* Time to discharge (min) a 104 31 92 18 146 52* Hypotension/bradycardia in the operating room d 2 2 2 Postanesthesia care unit IV Narcotics 5 2 2 Antiemetics 0 0 3* Antiemetics 0 0 3* Antipruritic 0 0 7* Follow-up Headache 1 3 3 c Pain control 1 1 1 Back/leg pain 0 2 1 Satisfaction scores: 5 (very satisfied) 12 12 8 4 (satisfied) 3 3 6 3 (neutral) 1 1 1 2 (dissatisfied) 0 1 a Average sd. b Time from postanesthetic care unit admission to void. c HR 60, systolic blood pressure 100 mm Hg requiring treatment. d One patient had a positional headache; none required treatment. *P 0.05. reliable block above T-10 with optimal discharge duration for outpatient spinal anesthetic. In our study of the three techniques, propofol/ nitrous oxide general anesthesia provided a duration of recovery similar to that after epidural anesthesia with 2-chloroprocaine. Spinal anesthesia required on average 42 to 54 minutes longer for recovery than the general or epidural group. The spinal group also had a higher incidence of side effects, specifically pruritus, which was attributed to the addition of the fentanyl to the procaine, as well as one occurrence of positional headache in the 16 patients. Room turnover times were not different among the groups, although the number of procedures performed sequentially in the same OR was small in our study, and does not allow significant conclusions. The level of patient satisfaction was equally high among all three groups. No patients in the epidural group had lower back pain after chloroprocaine, nor were there any symptoms of TNS in the spinal group. No patients had urinary retention in the PACU. Omitting the requirement for voiding would have reduced the discharge times for both the epidural and spinal group, but further study is needed to substantiate the safety of such a practice (18). It appears that the use of either propofol general anesthesia or chloroprocaine epidural anesthesia provide rapid discharge for outpatient knee arthroscopy. The choice between these two may be based on the patient s desire to be awake and alert during the surgical procedure. There are several potential limitations of our study. First, it was impossible to perform this study in a blinded fashion because of the nature of the anesthetics. Outcome data points (discharge times), however, were collected by an observer every 15 minutes using objective PACU recovery criteria. Room turnover times were likewise an objective time measure. A second problem was a limited number of comparisons in room turnover times. In our outpatient surgical center, surgeons often do not follow themselves in the same room. Nevertheless, for the limited number of observations, there was no difference in the turnover times among groups. Epidural anesthesia in our setting is performed in an induction area outside the OR, while the OR itself is being prepared for the next case. Subsequent transfer of the patient to the OR allows additional time for onset of anesthesia. Longer turnover times may be found if such an area is not available. Although our study may provide a valid comparison of ideal general and epidural anesthesia techniques, we may not have identified the ideal local anesthetic or dose for outpatient spinal anesthesia. The shortest previously reported duration is with 40 mg of lidocaine (12), but this dose was associated with a 10% failure rate and lidocaine has been associated with symptoms of TNS. Bupivacaine has been recommended as an alternative, but its duration is equivalent to 50 mg lidocaine anesthesia. We chose a relatively small dose of procaine with fentanyl to reduce the probability of TNS and shorten discharge, but still found discharge times comparable to 50 mg lidocaine, with a high side effect profile that included nausea, pruritus, and positional headache. Further study is needed to determine whether there is a

864 AMBULATORY ANESTHESIA MULROY ET AL. ANESTH ANALG ANESTHESIA FOR KNEE ARTHROSCOPY 2000;91:860 4 drug or dose regimen that would provide an equivalent duration and side effect profile to epidural chloroprocaine. We had a relatively low recruitment to our study (51 of 192), which might suggest a bias of the participants. However, we found that those who did consent to randomization appeared to be least prejudiced as to the relative advantages of the techniques. The patients with strong convictions about the choice of anesthetic did not participate in the study. On the other hand, this patient prejudice that we encountered could be a significant factor in the choice of anesthetic. The majority of our patients who refused randomization (95 of 141) preferred being awake, observing the arthroscopic procedure on the video screen. In an outpatient population, this preference for alertness may serve as a primary criteria for the choice of anesthetic technique, based on our data of equivalent side effects and recovery times. In conclusion, we performed a prospective, randomized comparison of general, epidural and spinal anesthesia for outpatient knee arthroscopy. Epidural anesthesia with chloroprocaine and general anesthesia with propofol-nitrous oxide provided equally effective intraoperative conditions and PACU discharge times in our outpatient center. Spinal anesthesia with 75 mg of procaine with fentanyl in this setting was associated with an average of 42 to 54 minutes longer discharge times than the other two techniques, and a higher incidence of side effects. Further study will be needed to identify an appropriate spinal anesthetic that would produce discharge times equivalent to the results obtained with general or epidural anesthesia in this setting. Either general or epidural anesthesia provide satisfactory anesthesia for outpatient knee arthroscopy and the choice of anesthetic technique may be primarily dependent on the patient s desire to be alert and participatory during the surgical procedure. The authors wish to thank Deanna Boltz, RN, for help in collection of data, and David Kerr for statistical analysis. 2. Patel NJ, Flashburg MH, Paskin S, Grossman R. Regional anesthetic technique compared to general anesthesia for outpatient knee arthroscopy. Anesth Analg 1986;65:185 7. 3. Ben-David B, Levin H, Solomon E, et al. Spinal bupivacaine in ambulatory surgery: The effect of saline dilution. Anesth Analg 1996;83:716 20. 4. Pavlin DJ, Rapp SE, Polissar NL, et al. Factors affecting discharge time in adult outpatients. Anesth Analg 1998;87:816 26. 5. Luttropp HH, Orlanders K, Ikonomidou E. Spinal, sevoflurane, or propofol anesthesia for outpatient knee arthroscopy [abstract]. Anesthesiology 1998;89:A41. 6. Hodgson PS, Liu SS, Batra MS, et al. Procaine compared to lidocaine for incidence of TNS. Reg Anesth Pain Med 2000;25: 218 22. 7. Goranson BD, Lang S, Cassidy JD, et al. A comparison of three regional anaesthesia techniques for outpatient knee arthroscopy. Can J Anaesth 1997;44:371 6. 8. Casati A, Fanelli G, Borghi B, Torri G. Ropivacaine or 2% mepivacaine for lower limb peripheral nerve blocks. Anesthesiology 1999;90:1047 52. 9. Dahl V, Gierloff C, Omland E, Raeder JC. Spinal, epidural or propofol anaesthesia for outpatient knee arthroscopy? Acta Anaesthesiol Scand 1997;41:1341 5. 10. Kopacz D, Mulroy MF. Chloroprocaine and lidocaine decrease hospital stay and admission rate after outpatient epidural anesthesia. Reg Anesth 1990;15:19 25. 11. Stevens RA, Urmey WF, Urquarht BL, Kao TC. Back pain after epidural anesthesia with chloroprocaine. Anesthesiology 1993; 78:492 7. 12. Urmey WF, Stanton J, Peterson M, Sharrock NE. Combined spinal-epidural anesthesia for outpatient surgery: doseresponse characteristics of intrathecal isobaric lidocaine using a 27-gauge Whitacre spinal needle. Anesthesiology 1995;83: 528 34. 13. Freedman JM, Li DK, Drasner K. Transient neurologic symptoms after spinal anesthesia. Anesthesiology. 1998;89:633 641. 14. Ben-David B, Solomon E, Levin H, et al. Intrathecal fentanyl with small-dose dilute bupivacaine: better anesthesia without prolonging recovery. Anesth Analg. 1997;85:560 5. 15. Chiu AA, Liu S, Carpenter RL, et al. The effects of epinephrine on lidocaine spinal anesthesia: a crossover study. Anesth Analg 1995;80:735 9. 16. Liu S, Chiu AA, Carpenter RL, et al. Fentanyl prolongs lidocaine spinal anesthesia without prolonging recovery. Anesth Analg 1995;80:730 4. 17. Axelrod EH, Alexander GD, Brown M, Schork MA. Procainespinal anesthesis: a pilot study of the incidence of transient neurologic symptoms. J Clin Anesth. 1998;10:404 9. 18. Pavlin DJ, Pavlin KG, Gunn HC. Voiding in patients managed with or without ultrasound monitoring of bladder volume after outpatient surgery. Anesth Analg 1999;89:90 7. References 1. Parnass SM, McCarthy RJ, Bach BR, et al. Beneficial impact of epidural anesthesia on recovery after outpatient arthroscopy. Arthroscopy 1993;9:91 5.