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*Department of Anaesthesia, Lapland Central Hospital, Rovaniemi, Finland;
Department of Anaesthesia and Intensive Care, University of Helsinki, Helsinki, Finland.
Address correspondence and reprint requests to Anna-Maija Korhonen, MD, HUCH, Department of Anaesthesia and Intensive Care Med, Meilahti Hospital, PO. Box 340, FIN-00029 HUS, Finland. Address e-mail to anna-maija.korhonen{at}hus.fi
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Abstract |
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IMPLICATIONS: Patients undergoing ambulatory knee arthroscopy recover equally fast when using either selective spinal anesthesia with hyperbaric bupivacaine or general anesthesia with desflurane. Spinal anesthesia is associated with decreased pain scores and less postoperative nausea and vomiting in the hospital.
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Introduction |
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The goal of this study was to assess whether SSA with small-dose hyperbaric bupivacaine provides an equal possibility of fast-tracking, a shorter stay in the postanesthesia care unit (PACU), and earlier discharge home compared with GA with desflurane.
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Methods |
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We used a sealed envelope technique with computer-generated numbers to randomize the patients prospectively into two groups: the SSA group and the GA group. The patients were given 600 mg of ibuprofen or 1000 mg of paracetamol PO preoperatively. An IV infusion was started before anesthesia and standard monitoring (electrocardiograph, noninvasive arterial blood pressure, and pulse oximetry) was used. Bradycardia <50 bpm was treated with glycopyrrolate and bradycardia <40 bpm was treated with atropine, and hypotension <90 mm Hg or systolic arterial blood pressure decreasing more than 50 mm Hg from the baseline were treated with etilefrine. Postoperative pain was evaluated with a visual analog scale (VAS) from 0 = no pain to 10 = the worst pain imaginable. Severe postoperative pain (VAS >7) was treated with fentanyl IV (up to 0.1 mg), moderate pain (3<VAS<8) with a combination of paracetamol and codeine (0.5 g of paracetamol and 30 mg of codeine x 1–2) PO, or if contraindicated, with tramadol (100 mg) IV/PO. If the pain relief was still insufficient, the patients received IV oxycodone (3–5 mg IV repeatedly until pain relief) and were admitted to the hospital. The Bispectral index (BIS) and the adductor pollicis train-of-four (TOF) ratio (by using kinemyographic measurement with Datex-Ohmeda MechanoSensor®; Datex-Ohmeda, Helsinki, Finland) were monitored in the GA group. The inspired and end-tidal concentrations of oxygen, CO2, desflurane, and N2O were also monitored.
SSA Group
The patients in the SSA group received 4 mg (0.8 mL) of hyperbaric bupivacaine injected through a 27-gauge cutting needle (Becton-Dickinson Yale Spinal; Becton-Dickinson, Franklin Lakes, NJ). A very low-flow (i.e., 0.4 mL/min) steady injection, at the lumbar 2/3 interspace with the bevel of the needle directed laterally towards the nerves involved, was used. The patient was maintained in a lateral decubitus position, the operative side dependent, for 10 min. Before the spinal injection, a level was used to ensure that the vertebral column was horizontal. Perioperatively, the patients were given midazolam up to 2 mg IV and/or alfentanil up to 0.5 mg IV when needed. If the dermatomes L1–5 were not blocked, the spinal anesthesia was considered to have failed. The sensory block to cold stimulus was tested by using thermal stimuli (acetone drop) (7,8). The motor block was assessed according to a modified Bromage scale (7,8). After the release of the tourniquet, and every 20 min thereafter, the sensory and motor block were evaluated until the transfer to the ambulatory surgery unit (ASU). The time in the PACU was recorded as the time from admission to the PACU until transfer to ASU. The PACU discharge was evaluated by using both the new fast-tracking scoring system by White and Song (9) and also by complete recovery of motor block, sensory block not above Th12, and the ability to sit up. The patient was fast-tracked to ASU if the latter criteria were fulfilled at the end of surgery and if the new fast-tracking criteria were also fulfilled.
GA Group
The risk for postoperative nausea and vomiting (PONV) was assessed before GA (10). The patients with more than two risk factors (female, nonsmoker, history of PONV, or motion sickness) were given prophylactic dexamethasone 5 mg IV after induction and 5-HT3 antagonist (ondansetron 4 mg) IV at the end of surgery. Rescue medication for PONV was provided by metoclopramide 10 mg IV for the patients with the prophylaxis and ondansetron 4 mg IV for the patients without prophylaxis. GA was induced with propofol 2–3 mg/kg and 0.1 mg fentanyl. To facilitate the tracheal intubation a dose of 0.4 mg/kg of rocuronium was administrated IV (11). The anesthesia was maintained with desflurane 2%–6% and 50% N2O in O2 titrated to keep the BIS index value between 50 and 60 towards the end of surgery. Additional fentanyl 0.05 mg IV was allowed when clinically indicated (SAP or heart rate more than 15% above the baseline values). All patients were mechanically ventilated to maintain an end-tidal CO2 concentration of 4.5–5.5kPa. A bolus dose of rocuronium (0.1 mg/kg IV) was administered if required (high peak inspiratory pressure values or coughing). A neuromuscular reversal drug was used if the TOF ratio was <0.8 (12) at the end of the operation. When the tourniquet was released, desflurane and N2O were discontinued. The patients were tracheally extubated when fully awake. The recovery status was assessed after extubation and every 20 min thereafter by using the new fast-track scoring system (9). A minimum score of 12 of 14 with no zero scores was required for the patient to be fast-tracked. Before transferring to ASU the patient had to be able to sit up, and those patients with vertigo or somnolence or those who wanted to lie down were kept in the PACU even if their fast-tracking score was 
12.
The anesthesia preparation time (APT) was recorded as the time from ensuring the posture of the vertebral column until the end of the 10 min required for the patient to maintain the lateral decubitus position in the SSA group. In the GA group, the APT was considered as the time from the beginning of injection of the induction drugs until connection of the patient to a respirator. Immediate recovery time from anesthesia was recorded as the time from release of the tourniquet until tracheal extubation and orientation. Together, the APT and the immediate recovery time were considered as the anesthesia-related time. Walking, voiding, and home-readiness were measured from the release of the tourniquet. Home-discharge criteria consisted of absence of nausea, vomiting and bleeding, minimal or no pain, and ambulating. Voiding was not required before home-readiness but the time to void was recorded if the patient had not yet left the hospital (for example, if no escort arrived). Postoperative pain, PONV, headache, and notable tiredness were recorded. Four to seven days after operation, a telephone interview was conducted to inquire about possible headache, backache, pain, postdischarge nausea or vomiting, dysuria, transient neurological symptoms (TNS), or postdural puncture headache. TNS was described as transient pain/dysesthesia in the back radiating to buttocks or legs on areas not related to the surgery. The patient’s satisfaction with the anesthesia was also assessed.
The sample size of 28 per treatment group was calculated to detect a 20% difference in the home-discharge time (140 min (4) in the GA group versus 110 min (7,8) in the SSA group) after surgery with 40% SD using an 
of 0.05 and a ß of 0.2. Because of possible dropouts, we decided to randomize 32 patients into both groups. The outcomes between the groups were statistically compared by calculating the P value for the null hypothesis of no difference using the 
2 test, Fisher’s exact test, and the Mann-Whitney U-test when appropriate. A P value <0.05 was considered significant. The SPSS for Windows (version 11.0.1) statistical package (SPSS Inc., Chicago, IL) was used.
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Results |
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8). At home, the pain was mild in both groups. In ASU, somnolence was significantly more frequent in the GA group.
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Bradycardia was treated in three versus eight patients (NS) and hypotension in zero versus seven patients (P = 0.011) after SSA and GA, respectively. Two of the patients who received medication for hypotension were elderly (ages 70 and 76 yr) and one belonged to ASA physical status III.
Ninety percent and 74% of the patients experienced the anesthesia to be superior to their expectations in the SSA and GA groups (NS), respectively. In the SSA group, one patient would choose GA instead of SSA in the future because of postdural puncture headache. In the GA group, six patients would like to have SSA instead of GA in the future. Four of them wished to be awake during the surgery and to be able to communicate with the surgeon and two of the patients would prefer SSA because of the side effects after GA.
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Discussion |
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Recovery from motor block is faster if intrathecal opioids are used in combination with small-dose local anesthetics (7). When we compared the SSA with a combination of 3 mg of bupivacaine + 10 µg of fen-tanyl with 4 mg of bupivacaine, we found a shorter PACU stay and a trend towards a better possibility of fast-tracking but equal time to home-readiness (171 versus 183 min, P = 0.172). As the reliability was equal (1 block versus 0 failed after B3F10 and B4) (7), we decided to use bupivacaine solely in the present study. In addition, even small doses of spinal opioids cause pruritus (7,13) and it seems that intrathecal opioids also cause dose-dependent PONV. In several studies, the 20–25 µg dose of intrathecal fentanyl has produced a 20%–30% incidence of PONV (14,15). Lennox et al. (3) found a 30% incidence of PONV in the SSA group with intrathecal lidocaine 10 mg mixed with sufentanil 10 µg compared with 0% in the GA group with desflurane. Neither in the present nor in our previous studies have any of the patients in the SSA group had PONV (7,8,13).
The time in PACU was relatively short in both groups. Although Jankowski et al. (2) fast tracked all patients after spinal anesthesia with 6 mg of bupivacaine and 15 µg fentanyl, we could fast-track only 12% of the patients in the SSA group. The different PACU bypass criteria between the studies might be an explanation. To fast track patients in the GA group, we estimated the White-Song fast-tracking criteria to be better for the GA patients as compared with the Aldrete scoring system (9). However, as the White-Song criteria were developed for patients undergoing ambulatory surgery with GA, we found them to be insufficient for patients undergoing SSA, and a complete recovery of motor block, the ability to sit up (without any symptoms), and sensory block not > Th12 was also required. Also, in the GA group, several patients with White-Song criteria 12 were admitted to the PACU instead of the ASU because, while they were sitting, they felt dizzy or somnolent. In the present study the PACU bypass criteria differed between the SSA and GA groups, a point that should be considered when interpreting the results of patients meeting fast-tracking criteria and time in PACU. In the future, when comparing GA and neuraxial anesthesia, PACU bypass criteria by Williams et al. (16) designed for both neuraxial and GA might be useful because they also include pain, PONV, shivering, and orthostasis.
The overall anesthesia-related time was 1.5 min longer in the SSA than in the GA group (Table 2). Although the difference was statistically significant, such a short time has only minor clinical relevance. In the SSA group, the anesthesia-related time consisted only of APT (17 min) because all the patients were awake and orientated at the time of tourniquet release. Similar preparation time was also found by Fanelli et al. (17) after unilateral spinal anesthesia. In the SSA group, a 17-min reduction in the OR time could have been achieved if an induction room had been used. However, this imposes other costs and requirements in terms of both physical plant and personnel. On the other hand, had we used the laryngeal mask airway (LMA) and spontaneous ventilation in the GA group, a reduction in anesthesia related time in the OR might also have been achieved in the GA group. In the present study, the patients could be tracheally extubated and were orientated 7.5 min after the release of the tourniquet in the GA group, whereas the time to orientation with desflurane LMA anesthesia was 3.4–4 min in the studies of Dolk et al. and Tang et al. (5,6). In the present study, the use of tracheal intubation and muscle relaxants instead of the LMA can be criticized and might have caused a bias in favor of SSA versus GA.
In the present study, time to home-readiness was similar in both groups. Equal home discharge times between SSA and GA groups were also noted in earlier studies (2,4). Although the patients in the study of Lennox et al. (3) could ambulate 3 min after surgery in the SSA group, as compared with 60 min in the GA group, the overall recovery times were equal, 112 min versus 101 min, in the SSA and GA groups, respectively.
In the hospital, postoperative pain VAS scores were significantly higher in the GA group compared with those in the SSA group, resulting in a need for more postoperative opioids. No difference in pain scores was noted at home. Jankowski et al. (2) also reported higher VAS scores (although mild pain) in GA than in spinal anesthesia patients. In their work, the local anesthetic used by the surgeon on both the arthroscopic portal site and intraarticular (IA) could explain the lower VAS scores. We did not have this procedure in our protocol because in our earlier studies, the patients with SSA had no problem with postoperative pain, either in the hospital or at home after knee arthroscopy. The use of IA morphine 5 mg might, nevertheless, have been beneficial in the GA group in decreasing the need for postoperative opioids (18) and the risk of PONV. Although 13 (41%) of the patients received PONV prophylaxis, six (19%) patients developed PONV in the GA group. Half of them had received the prophylaxis. The triple prophylaxis with the combination of dexamethasone, 5-HT3 antagonists, and droperidol could have been more effective in preventing PONV (19), but we wanted to avoid the use of droperidol in outpatients because of the possible QT prolongation (20) and the sedative effect. In the present study, TNS occurred in both groups. Although the exact mechanism remains unclear, the TNS is most frequent after lidocaine spinal anesthesia (10%–37%) compared with other local anesthetics and in patients undergoing knee arthroscopy (18%–22%) or surgery in the lithotomy position (30%–36%) (21). Interestingly, TNS also occurred after GA (6% of the patients), which could support the suggestion of the musculoskeletal origin of these symptoms and that patients undergoing knee arthroscopy are in risk of developing TNS.
In conclusion, patients undergoing ambulatory knee arthroscopy had equal likelihood of meeting fast-track criteria and discharge times after SSA with 4 mg of hyperbaric bupivacaine and after endotracheal GA with desflurane. However, those patients receiving SSA had lower pain scores and need of postoperative opioids, less PONV, and somnolence in the hospital.
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Acknowledgments |
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We are grateful for the help and support of Ms. Eija Ruoppa, RN, and the nurses at the Ambulatory Surgery Unit, to Ms. Marja-Liisa Putaansuu, RN, as well as to the personnel at the Anaesthesia Department of Lapland Central Hospital.
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S. S. Liu, W. M. Strodtbeck, J. M. Richman, and C. L. Wu A Comparison of Regional Versus General Anesthesia for Ambulatory Anesthesia: A Meta-Analysis of Randomized Controlled Trials Anesth. Analg., December 1, 2005; 101(6): 1634 - 1642. [Abstract] [Full Text] [PDF]
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