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Anesth Analg 2004;99:1521-1527 © 2004 International Anesthesia Research Society doi: 10.1213/01.ANE.0000134684.25322.26
David S. WARNER Section Editor |
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Abstract |
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Surgical procedures on the vertebral column may result in spinal cord damage, leading to neurological deficits that demand immediate therapeutical intervention. We designed this study to determine which anesthetic regimen allows a rapid wake-up test during and after surgery to detect neurological deficits. Fifty-four patients were randomly allocated to the following groups: group PR (propofol/remifentanil): target-controlled infusion with propofol (plasma concentration, 2–4 µg/mL) and remifentanil 0.2–0.5 µg · kg–1 · min–1; group PS (propofol/sufentanil): propofol (2–4 µg/mL) and repetitive boluses of 0.1–0.2 µg/kg of sufentanil adjusted to patients requirements; and group DR (desflurane/remifentanil): desflurane/air 3.0–4.0 vol% combined with remifentanil 0.2–0.5 µg · kg–1 · min–1. Group PS required significantly longer times for the onset of breathing (8.9 ± 1.6 min), elevation of the head (17.0 ± 3.8 min), and motion of the feet (17.0 ± 7.4 min) than group PR (6.9 ± 2.6 min, 9.3 ± 2.2 min, and 9.4 ± 2.4 min, respectively) or group DR (5.4 ± 0.8 min, 6.1 ± 1.0 min, and 6.2 ± 1.0 min, respectively). The anesthetic regimen with desflurane and remifentanil allowed faster awakening during and after surgery that permitted immediate neurological examination after spinal surgery compared with propofol/remifentanil.
IMPLICATIONS: The balanced anesthetic regimen with desflurane and remifentanil allows a more rapid initial awakening during and after surgery combined with an immediate neurological examination of good quality during spinal surgery compared with propofol and remifentanil.
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Introduction |
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Paraplegia is a rare but feared complication in patients undergoing surgical procedures on the vertebral column. Neurological complications should be detected sufficiently early so they can be surgically revised. Two methods are often used to detect intraoperative compromise of spinal cord function, although both are not infallible (1). Neurophysiological methods include the application of motor-evoked potentials and somatosensory-evoked potentials (SSEPs) (2–4). Changes in wave patterns signal the possibility of damage to the spinal cord. However, this technique is used only to monitor signal conduction in the sensory columns of the spinal cord. These tracts are posteromedially concentrated and thus away from the anterior aspect of the spinal cord, where the vascular insult generally occurs. Moreover, as changes in the anterior horn cells may result in changes in SSEP, a spinal cord injury may be missed with this technique (5). Therefore, the intraoperative wake-up test is still considered to be the "gold standard" and consists of waking patients during and immediately after completion of spinal procedures (5,6). During this crude test of motor function, patients are asked to squeeze the anesthesiologist’s hands and to move their feet before anesthesia is continued.
To apply intraoperative wake-up tests, the anesthetic regimen needs to enable a rapid patient recovery and an immediate neurological examination. The development of propofol and remifentanil as short-acting injectable anesthetics using the concepts of target-controlled infusion and total IV anesthesia provide an opportunity to make an intraoperative wake-up test more reliable (7).
Remifentanil is a novel member of the 4-anilindo-piperidine opioid analgesics (8). The extrahepatic metabolism of remifentanil by nonspecific esterases results in an extremely rapid clearance and an ultra-short context-sensitive half-time of approximately 3.5 min (9–11). Propofol is cleared from the central compartment by hepatic metabolism and kidney excretion (12). Clearance rates suggest an additional extra hepatic route of elimination. If the patient’s prompt recovery after surgery is the priority, desflurane as a volatile anesthetic is an alternative to the injectable drugs. As a consequence of its low blood and tissue solubility, times of awakening are fast (13).
Despite the need for fast recovery as well as immediate neurological examination, no investigations have been made to demonstrate which anesthetic regimen is superior when intraoperative wake-up tests are performed. Therefore, we investigated three different anesthetic regimens (propofol/sufentanil versus propofol/remifentanil versus desflurane/remifentanil) in patients undergoing spinal surgery with respect to return of psychomotor and cognitive functions during and after surgery. Furthermore, we recorded the demand of postoperative analgesia using patient-controlled analgesia (PCA) and pain relief scores (PRS).
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Methods |
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After obtaining ethical committee approval and written informed consent, 54 adult ASA I–III patients scheduled for spinal surgery (dorsal-, ventral-, and dorso-ventral stabilization) were included in this study. Patients were excluded from the study if they had a history of increased intracranial pressure, severe cardiovascular disease or if myocardial infarction was experienced 12 mo before the proposed surgery, neurological diseases, suspicion of malignant hyperthermia, current pregnancy, patients who were unable to follow verbal commands, or age
18 and 
75 yr old. In this single-blinded prospective study, the patients were randomly allocated to one of three groups: (a) group PS (n = 18): sufentanil (Sufentanil®, Janssen, Neuss, Germany) and propofol (Disoprivan®, Astra Zeneca, Wedel, Germany); (b) group PR (n = 18): propofol and remifentanil (Ultiva®, Glaxo Wellcome, London, UK); and (c) Group DR (n = 18): desflurane (Suprane®, Baxter, Unterschleissheim, Germany)/air with remifentanil.
Each patient received premedication with midazolam (Dormicum®, Roche, Grenzach-Wyhlen, Germany) 0.1 mg/kg and clonidine (generic hospital preparation) 2 µg/kg orally 90 min before the induction of general anesthesia. In the operating room, standard monitoring equipment, including 12-lead electrocardiography, pulse oximetry, and noninvasive arterial blood pressure, was attached, and an IV cannula for fluid and drug administration was introduced. After administration of 100% O2, anesthesia was induced with a bolus of propofol (target-controlled plasma concentration, 4 µg/mL) (group PR, PS, and DR) and remifentanil (plasma concentration, 0.5 µg/kg) (group PR and DR) or sufentanil (bolus, 0.5–1.0 µg/kg) (group PS). An IV bolus of cisatracurium 0.1 mg/kg (Nimbex®, Glaxo Wellcome) was given to facilitate the endotracheal intubation. The lungs were ventilated with a fraction of inspired O2 (FIO2) of 0.35 to maintain the end-tidal CO2 concentration at 35–40 mm Hg.
After the induction of anesthesia, an arterial line was inserted in the radial artery for invasive measurement of arterial blood pressure. Perioperatively, it was aimed to maintain a mean arterial blood pressure (MAP) between 60 and 70 mm Hg to avoid increased bleeding from the surgical wound and to ensure a sufficient anesthetic depth. In cases of MAP values <60 mm Hg or bradycardia, cafedrin/theoadrenalin (Akrinor®, AWD-Pharma, Dresden, Germany) or atropine (Atropinsulfat®, Braun, Melsungen, Germany) was administered, respectively. A central venous catheter was inserted in the right jugular vein for continuous measurement of central venous pressure and administration of fluids and drugs. Furthermore, a urine catheter with temperature measurement was placed in all patients.
Maintenance of anesthesia was as follows: group PS: propofol (plasma concentration, 2–4 µg/mL) combined with repetitive boluses of 0.1–0.2 µg/kg of sufentanil adjusted to patient requirements until 60 min before the first wake-up test (indicated by the surgeon as early as possible but not later than the requested time frame) or the end of the operation; group PR: target-controlled infusion with propofol (plasma concentration 2–4 µg/mL) combined with remifentanil 0.2–0.5 µg · kg–1 · min–1; group DR: desflurane/air end-tidal 3.0–4.0 vol% using a fresh gas flow rate of 2 L/min combined with remifentanil 0.2–0.5 µg · kg–1 · min–1.
At the surgeons’ request for the intraoperative wake-up test, the infusion of propofol, or inhalation of desflurane, was stopped. The infusion rate of remifentanil was reduced to a plasma concentration of 0.05 µg · kg–1 · min–1, and this dosage was continued throughout the duration of the intraoperative wake-up test to avoid pain during this procedure. Patients were asked repeatedly during the wake-up test, at least every 30 s, to open their eyes and to move their hands and feet. The times elapsed from the interruption of anesthesia to initial emergence (e.g., muscle fasciculations or movements), the onset of breathing, first reaction, elevation of the head, and motions of feet were recorded in seconds with a stopwatch. After finishing the wake-up test, the maintenance of anesthesia was continued, as previously described.
Thirty minutes before the end of surgery, all patients received IV novaminsulfone (Novalgin®, Ratiopharm, Ulm, Germany) 15 mg/kg as a peripherally acting analgesic. On completion of surgery, anesthesia was discontinued, and the postoperative wake-up test was performed. The times from the discontinuation of anesthesia to the onset of breathing, first reaction, elevation of the head, tracheal extubation, and the orientation of the patient (questions included information about the patient’s name and birth date, actual date, and present location) were recorded.
After completion of surgery, all patients were transferred to the postanesthesia care unit where hemodynamic monitoring was continued for at least 4 h. For postoperative pain relief, patients received a PCA pump using the IV opioid piritramide (concentration, 1.5 mg/mL) (Dipidolor®, Janssen) and a bolus of 1.5 mg with a 5 min lockout interval for 24 h. Efficacy of postoperative analgesic treatment was estimated using visual PRS ranging from 0 = no relief from pain to 100 = total relief from pain for 24 h after surgery. Furthermore, the amount of analgesic medication was recorded for 24 h.
Patients were monitored for adverse effects throughout the treatment phase. The presence or absence of shivering was noted up to 2 h after surgery. Shivering was treated with single doses of 0.5 mg/kg of meperidine (Dolantin®, Marion Roussel, Bad Soden, Germany).
For statistical analysis, SPSS for Windows version 10 (SPSS, Chicago, IL) was used. Significance of data was examined by analysis of variance followed by a post hoc Bonferroni corrected t-test. The data are reported as mean ± SD, and results were considered significant if P values were <0.05.
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Results |
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There were no significant differences among the groups for sex distribution, body weight, the duration of surgery, and anesthesia (Table 1). Patients in group DR were significantly younger than in groups PS and PR.
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After the induction, MAP decreased in all groups to the same extent and then stabilized (Fig. 1). On average, the MAP values of patients from group DR (72 ± 14 mm Hg), PS (81 ± 13 mm Hg), and PR (75 ± 12 mm Hg) were comparable and did not show any significant differences throughout the study period. There were no differences among groups for heart rate during the study. The incidences of bradycardia and need for treatment with atropine were also similar.
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In each patient, only one wake-up test was performed intraoperatively. The time from the onset of anesthesia to the time of the wake-up tests were not different among groups. The analyses of the intraoperatively performed wake-up tests are shown in Figure 2. The initial emergence from anesthesia in group PS was numerically slower than in group PR and significantly slower in group DR. Subjects receiving propofol/sufentanil took longer for the onset of breathing, elevation of the head, and motion of the feet than subjects who received propofol/remifentanil or desflurane/remifentanil.
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P < 0.05 versus PS.A pattern similar to the wake-up test was observed after surgery (Fig. 3). Patients in group PS had longer times to the onset of the first reaction, elevation of the head, and motion of the feet compared with those in group PR. Patients in group DR had on average the shortest times in all measured categories. These results were statistically significant in comparison to groups PR and PS.
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The times to tracheal extubation and orientation after surgery are presented in Figure 4. Subjects in group DR had the shortest times to extubation and orientation with respect to personal information, date, and present location. Participants in group PS had the longest times for extubation and orientation, followed by group PR.
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After 24 h, the total dose of piritramide was similar among groups (PR, 75.4 ± 47.3 mg; PS, 68.8 ± 34.5 mg; and DR, 73.8 ± 36.3 mg). There was no significant difference at any point in time between the PRS of the different groups (Fig. 5). The scores tended to increase with time in all three groups.
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In the PS and PR groups, one patient developed postoperative shivering. The frequency of observed shivering in group DR was 5 of 18 participants. All patients with shivering were successfully treated with meperidine.
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Discussion |
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Paraplegia is one of the most feared complications of spinal surgery. Therefore, it is necessary to detect spinal injury as early as possible. Electrophysiological methods and intraoperative wake-up tests are used to monitor spinal cord function during surgery. Continuous intraoperative monitoring of SSEP is used widely in spinal surgery. However, this technique is used only to monitor signal conduction in the sensory columns of the spinal cord. These tracts are posteromedially concentrated and thus away from the anterior aspect of the spinal cord where the vascular insult generally occurs. Furthermore, anesthetics might influence the reliability, especially of motor-evoked potential monitoring.
The wake-up test, also known as Stagnara test (14), monitors voluntary motor function once the vertebrae have been distracted and instrumented. Advantages of the wake-up test are that it is simple to perform and does not require sophisticated equipment (15). The wake-up test has been considered the gold standard of spinal monitoring, but its weaknesses are that it misses the onset of injury or ischemia and does not identify isolated nerve injury or subtle changes. For these reasons, the wake-up test can be used in conjunction with electrophysiological methods (1). The combination of methods is especially beneficial for patients when electrophysiological monitoring shows deteriorating responses or when normal electrophysiological results must be confirmed.
The performance of wake-up tests requires an anesthetic regimen that provides for fast recovery and fast return of cognition to allow immediate examination. In this clinical trial, it could be demonstrated that recovery from anesthesia during the intraoperative wake-up was most rapid after administration of desflurane and remifentanil.
The rapid clearance of remifentanil by nonspecific esterases results in short and predictable drug duration and ultra-short context-sensitive half-time (16). In combination with desflurane, which is characterized by low blood and tissue solubility, times of awakening are fast and predictable (17). These results confirm observations from other studies, which indicate that remifentanil, in combination with volatile anesthetics, allows faster recovery than anesthesia that use a combination of remifentanil or other opioids and propofol for short-term and intermediate-term anesthesia (18–20). After long infusion times, which correspond with the interval to the postoperative wake-up test in this study, elimination of propofol and sufentanil is quite different. The effect of longer durations of anesthesia on emergence was observed after propofol/remifentanil and propofol/sufentanil administration. Propofol was thus the limiting drug in defining the time to recovery of cognition, even if used as target-controlled infusion. Because of its high lipid-solubility, long infusion rates of propofol lead to accumulation in fatty tissue and therefore to extended times of emergence (21), which is shown in the statistically significant difference of emergence between group PR and DR. This result is reflected in a study from Juvin et al. (22), who demonstrated that obese patients have longer times of awakening if propofol is administered in comparison to inhaled desflurane. Because of its low solubility, less desflurane needs to be released from the tissues and eliminated from the body at the end of prolonged anesthesia. Therefore, the duration of inhaled desflurane has little or no influence on recovery time (23). This notion also explains that the times for recovery are extended in the postoperative phase in comparison to the times for recovery in the intraoperative phase for patients in group PR but not for patients in group DR.
The extension for emergence in group PS in comparison to group PR was most likely caused by the repetitive boluses of sufentanil. This leads to an accumulation with prolonged times of awakening, whereas remifentanil still undergoes a rapid on/off mechanism because of its pharmacokinetics, even after long infusion intervals. These results are also reflected in the times obtained to final orientation as well as extubation. These effects have also been shown in two cases of patients undergoing surgery of the anterior cervical spine in which remifentanil provided rapidly titratable anesthesia and facilitated intraoperative wake-up tests (24).
Regardless of the aim to allow immediate neurological examination and to choose an adequate anesthetic regimen, it is crucial to ensure hemodynamic stability during surgery. Hypotensive anesthesia has been widely used in spinal surgery to reduce blood loss and to facilitate a bloodless wound. The beneficial effects of this anesthetic technique remain controversial (25,26). Although propofol and desflurane have depressant cardiovascular effects, none of the patients developed severe cardiac complications. Hypotension and bradycardia occurred with a similar frequency in all groups and were simply treated either with an increased infusion of cafedrin/theoadrenalin or a bolus of atropine, respectively.
Because it is possible that there may be a recall during the intraoperative wake-up test, all patients must be informed about this risk (27). However, none of the patients reported recall, which underlines the safety of the administration of these different drug schemes.
Administration of remifentanil can cause early postoperative pain because of the quick offset of its analgesic action (28). Thus, it is required that transitional analgesia is provided. To prevent early postoperative pain, all patients received novaminsulfone, a nonsteroidal antiphlogistic drug, 30 minutes before the end of surgery followed by the administration of a PCA pump with piritramide (29). The analyses of the demand of piritramide 24 hours after surgery showed that the demand for additional analgesics was similar in all groups.
The patients in group PS had slightly less but insignificant demand for piritramide after surgery, which may have been caused by the longer half-life of sufentanil. These findings show that the administration and combination of short-acting anesthetics such as remifentanil and desflurane, despite their pharmacokinetics, do not have any disadvantage in the postoperative phase in comparison to longer acting anesthetics.
The major limitation of this study is the equivalent depths of anesthesia as the starting point in the different groups. It was not feasible in this clinical trial to ensure (e.g., electroencephalogram) that patients’ recovery started from the same level of anesthesia. To minimize differences in measuring, as well as observer bias, all anesthetics were provided by the same experienced anesthesiologist using routinely applied clinical variables. The doses of the anesthetics required to achieve a state of surgical anesthesia were similar to other studies that judged the depths of anesthesia clinically or by electroencephalogram (30–32).
Fast emergence and immediate neurological evaluation are highly desirable if wake-up tests are performed. This clinical study provides evidence that remifentanil and desflurane-based anesthesia offer the most advantages to achieve this goal. Although both anesthetics undergo rapid elimination, expected disadvantages in the postoperative phase were not observed and were comparable to conventional anesthetic regimens. As a result of this trial and corresponding findings from other studies (33), we recommend the use of desflurane and remifentanil if rapid neurological examination is required.
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Footnotes |
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Presented, in part, at the Annual Meeting of the American Society of Anesthesiologists, San Diego, CA, 2001.
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References |
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TopAbstractIntroductionMethodsResultsDiscussionReferences |
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- Padberg AM, Wilson-Holden TJ, Lenke LW, et al. Somatosensory- and motor-evoked potential monitoring without a wake-up test during idiopathic scoliosis surgery: an accepted standard of care. Spine 1998; 23: 1392–400.[Web of Science][Medline]
- Owen JH, Bridwell KH, Grubb RL, et al. The clinical application of neurogenic motor evoked potentials to monitor spinal cord function during surgery. Spine 1991; 7: 385–90.
- Owen JH. Intraoperative stimulation of the spinal cord for prevention of spinal cord injury. Adv Neurol 1993; 63: 271–88.[Medline]
- Owen JH, Laschinger J, Bridwell KH, et al. Sensitivity and specificity of somatosensory and neurogenic-motor evoked potentials in animals and humans. Spine 1988; 13: 1111–8.[Medline]
- Hoppenfeld S, Gross A, Andrews G, Lonner B. The ankle clonus test for assessment of the integrity of the spinal cord during operations for scoliosis. J Bone Joint Surg 1997; 79: 208–12.
[Abstract/Free Full Text] - Ben-David B. Spinal cord monitoring. Orthop Clin North Am 1988; 19: 427–45.[Medline]
- Russell D, Wilkes MP, Hunter SC, et al. Manual compared with target-controlled infusion of propofol. Br J Anaesth 1995; 75: 562–6.
[Abstract/Free Full Text] - Scholz J, Steinfath M. Is remifentanil an ideal opioid for anesthesiologic management in the 21st century? Anasthesiol Intensivmed Notfallmed Schmerzther 1996; 31: 592–607.[Medline]
- Egan TD. Remifentanil pharmacokinetics and pharmacodynamics: a preliminary appraisal. Clin Pharmacokinet 1995; 29: 80–94.[Web of Science][Medline]
- Egan TD, Lemmens HJ, Fiset P, et al. The pharmacokinetics of the new short-acting opioid remifentanil (GI87084B) in healthy adult male volunteers. Anesthesiology 1993; 79: 881–92.[Web of Science][Medline]
- Hughes MA, Glass PS, Jacobs JR. Context-sensitive half-time in multicompartment pharmacokinetic models for intravenous anesthetic drugs. Anesthesiology 1992; 76: 334–41.[Web of Science][Medline]
- Trapani G, Altomare C, Liso G, et al. Propofol in anesthesia: mechanism of action, structure activity relationships, a drug delivery. Curr Med Chem 2000; 7: 249–71.[Web of Science][Medline]
- Scholz J, Tonner PH. Desflurane and sevoflurane: an interim balance. Anaesthesist 1997; 46: 816–25.[Medline]
- Vauzelle C, Stagnara P, Jouvinroux P. Functional monitoring of spinal cord activity during spinal surgery. Clin Orthop 1973; 93: 173–8.
- Chamberlain ME, Bradshaw EG. The ‘wake-up test’: a new approach using drug infusions. Anaesthesia 1985; 40: 780–2.[Medline]
- Egan TD, Minto CF, Hermann DJ, et al. Remifentanil versus alfentanil: comparative pharmacokinetics and pharmacodynamics in healthy adult male volunteers. Anesthesiology 1996; 84: 821–33.[Web of Science][Medline]
- Eger EI II, Gong D, Koblin DD, et al. The effect of anesthetic duration on kinetic and recovery characteristics of desflurane versus sevoflurane, and on the kinetic characteristics of compound A, in volunteers. Anesth Analg 1998; 86: 414–21.[Abstract]
- Larsen B, Seitz A, Larsen R. Recovery of cognitive function after remifentanil-propofol anesthesia: a comparison with desflurane and sevoflurane anesthesia. Anesth Analg 2000; 90: 168–74.
[Abstract/Free Full Text] - Wilhelm W, Huppert A, Brün K, et al. Remifentanil with propofol or isoflurane: comparison of recovery times after arthroscopic surgery. Anaesthesist 1997; 46: 335–8.[Web of Science][Medline]
- Grundmann U, Uth M, Eichner A, et al. Total intravenous anaesthesia with propofol and remifentanil in paediatric patients: a comparison with desflurane-nitrous oxide inhalation anaesthesia. Acta Anaesthesiol Scand 1998; 42: 845–50.[Web of Science][Medline]
- Apfelbaum JL, Lichtor JL, Lane BS, et al. Awakening, clinical recovery, and psychomotor effects after desflurane and propofol anesthesia. Anesth Analg 1996; 83: 721–5.[Abstract]
- Juvin P, Vadam C, Malek L, et al. Postoperative recovery after desflurane, propofol, or isoflurane anesthesia among morbidly obese patients: a prospective, randomized study. Anesth Analg 2000; 91: 714–9.
[Abstract/Free Full Text] - Eger EI II. Desflurane animal and human pharmacology: aspects of kinetics, safety, and MAC. Anesth Analg 1992; 75: 3–9.
- Kimball-Jones PL, Schell RM, Shook JP. The use of remifentanil infusion to allow intraoperative awakening for intentional fracturing of the anterior cervical spine. Anesth Analg 1999; 89: 1059–61.
[Free Full Text] - Lee TC, Buerkle H, Wang CJ, et al. Effect of isoflurane versus nicardipine on blood flow of lumbar paraspinal muscles during controlled hypotension for spinal surgery. Spine 2001; 26: 105–9.[Medline]
- Lawhon SM, Kahn A III, Crawford AH, et al. Controlled hypotensive anesthesia during spinal surgery: a retrospective study. Spine 1984; 9: 450–3.[Medline]
- McCann ME, Brustowicz RM, Bacsik J, et al. The bispectral index and explicit recall during the intraoperative wake-up test for scoliosis surgery. Anesth Analg 2002; 94: 1474–8.
[Abstract/Free Full Text] - Wilhelm W, Biedler A, Larsen R. Remifentanil. Anaesthesist 1997; 46: 992–7.[Medline]
- Wulf H. Pro: patient-controlled analgesia (PCA). Anasthesiol Intensivmed Notfallmed Schmerzther 1999; 34: 102–4.[Medline]
- Hogue CWJ, Bowdle TA, O’Lary et al. A multicenter evaluation of total intravenous anesthesia with remifentanil and propofol for elective inpatient surgery. Anesth Analg 1996; 83: 279–85.[Abstract]
- Nathanson MH, Fredman B, Smith I, et al. Sevoflurane versus desflurane for outpatient anesthesia: a comparison of maintenance and recovery profiles. Anesth Analg 1995; 81: 1186–90.[Abstract]
- Wilhelm W, Kuster M, Larsen B, et al. Desflurane and sevoflurane: a comparison of emergence times and haemodynamics during surgical procedures. Anaesthesist 1996; 45: 37–46.[Web of Science][Medline]
- Rodola F, D’Avolio R, Chierichini A, et al. Wake-up test during major spinal surgery under remifentanil balanced anaesthesia. Eur Rev Med Pharmacol Sci 2000; 4: 67–70.[Medline]
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