- Email: [email protected]
Standard Anesthetic Technique for Middle Ear Surgical Procedures: A Comparison of Desflurane and Sevoflurane
Otolaryngology–Head and Neck Surgery (2005) 133, 269-274
Standard Anesthetic Technique for Middle Ear Surgical Procedures: A Comparison of Desflurane and Sevoflurane W. Scott Jellish, MD, PhD, Kevin Owen, MD, Steven Edelstein, MD, Elaine Fluder, RN, MSN, and John P. Leonetti, MD, Maywood, Illinois OBJECTIVE: This study was designed to compare desflurane and sevoflurane anesthesia for middle ear microsurgery. STUDY DESIGN: One hundred healthy adults undergoing middle ear surgery were assigned to receive either desflurane or sevoflurane as their anesthetic. Intraoperative hemodynamics and BIS numbers were recorded. Hemodynamics, pain, nausea/vomiting, discharge readiness, and other parameters were compared postoperatively and 24 hours later. RESULTS: No intraoperative differences were noted except in BIS scores which trended lower with desflurane. PACU blood pressures were higher after desflurane but pain scores, nausea/ vomiting, rescue anti-emetics, recovery scores, and discharge times were similar. A significant difference was noted in anesthetic costs (desflurane ⬎ sevoflurane), and in patients with the lowest BIS scores associated with more nausea/vomiting. CONCLUSIONS: Both anesthetics may be used for ototic surgery but propofol anesthesia should still be considered in patients with a history of emetic sequelae. SIGNIFICANCE: Short-acting inhalational anesthetics produce excellent operating conditions and reduce costs for otologic surgery. © 2005 American Academy of Otolaryngology–Head and Neck Surgery Foundation, Inc. All rights reserved.
M
iddle ear surgical procedures require an anesthetic technique that produces a motionless, bloodless surgical field and minimal postoperative nausea and vomiting (PONV). In addition, the need for intraoperative monitoring of the facial nerve during surgery requires that the patient remain unparalyzed during the most stimulating portions of From the Departments of Anesthesiology (Drs Jellish, Owen, and Edelstein and Ms Fluder) and Otolaryngology (Dr Leonetti), Loyola University Medical Center. Presented at the Annual Meeting of the American Academy of Otolaryngology–Head and Neck Surgery, New York, NY, September 19-22, 2004.
the surgery. Therefore, the anesthesiologist must use an anesthetic technique that provides a sufficiently deep level of anesthesia with minimal intraoperative movement, rapid emergence, and decreased postsurgical morbidity. Previously, our group evaluated a propofol-based anesthetic technique and compared this to a standard inhalational anesthetic for middle ear surgery and concluded that the propofol technique produced acceptable perioperative conditions and reduced the incidence of PONV.1 Remifentanil-based anesthesia with low-dose propofol was also compared to a propofol-based technique and was found to provide better hemodynamic control, less movement, and faster emergence, yet with the same anti-emetic effect.2 However, the costs associated with these intravenous (IV) techniques are much higher and total propofol techniques may increase time to emergence and extubations.3 Desflurane is a volatile anesthetic agent with a low solubility that allows for rapid induction and fast emergence from anesthesia. Sevoflurane, another volatile anesthetic, also has a low solubility, making it a good agent for rapid induction and fast emergence from anesthesia. In addition, this anesthetic produces much less airway irritability and may produce less coughing, breath holding, and postoperative complications. Studies comparing desflurane and sevoflurane have shown that desflurane leads to a more rapid emergence and shorter time to extubation with faster cognitive and psychomotor recovery, but a greater incidence of postoperative sore throat and a higher incidence of postoperative agitation and excitement.4-7 However, there Reprint requests: W. Scott Jellish, MD, PhD, Department of Anesthesiology, Loyola University Medical Center, 2160 S. First Avenue, Maywood, IL 60153. E-mail address: [email protected].
0194-5998/$30.00 © 2005 American Academy of Otolaryngology–Head and Neck Surgery Foundation, Inc. All rights reserved. doi:10.1016/j.otohns.2005.04.011
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has been conflicting data in regard to the incidence of postoperative morbidity after using these two anesthetics.8-9 No prior study has compared the efficacy, postoperative morbidities, and intraoperative variables of these two inhalation agents for middle ear surgeries. This study compares the perioperative effect of these two agents in patients undergoing middle ear surgical procedures and attempts to determine if one agent is superior to the other in the incidence of postoperative morbidities, recovery parameters, and cost effectiveness.
METHODS After Institutional Review Board approval, 100 healthy adult patients (ages 18-65) undergoing elective middle ear surgery were consented and enrolled into the study. These surgeries included stapedectomies, mastoidectomies, ossiculoplasties, endolymphatic sac decompressions, and tympanoplasties. Patients were excluded from the study if they had medical conditions known to increase the incidence of nausea and vomiting, with delayed gastric emptying (diabetes, chronic cholecystitis, neuropathy, neuromuscular disease), pregnancy, or obesity (body mass index ⬎ 30). Bispectral index (BIS) was used to titrate each patient to a similar anesthetic depth denoted by a BIS number of approximately 40. This level of hypnosis is associated with a lower incidence of movement and implicit recall as compared to standard anesthetic titration techniques.10 The patients were equally divided and randomly assigned into one of two groups. Group 1 patients received an anesthetic composed of propofol 2 mg/kg IV for induction of anesthesia, followed by maintenance anesthesia using desflurane 6%–9% end-tidal (ET) at fresh gas flows of 2 to 3 liters/minute in a 50% air/oxygen mixture. Patients in Group 2, again, received propofol 2 mg/kg IV for induction, followed by sevoflurane 2%–3% ET at similar fresh gas flows. Both groups received midazolam 2 mg IV prior to initiation of anesthesia. After induction, both groups received fentanyl 2 mcg/kg IV, and atracurium 0.5 mg/kg IV to facilitate intubation. Neither group received additional muscle relaxant or neuromuscular reversal drugs. The patients had an orogastric tube placed to decompress the stomach prior to the start of the surgery. During the preinduction period, EEG gel surface adhesive electrodes were placed in a fronto-occipital montage pattern over the cortex. BIS monitoring began 1 minute prior to induction of anesthesia with the patient quietly resting on the operating table to establish a baseline. BIS monitoring continued throughout the remainder of the surgery and was discontinued after emergence from anesthesia and prior to the patient’s being brought to the postanesthesia care unit (PACU). Hemodynamic responses to laryngoscopy and intubation were recorded, as was the response to surgical incision and
mastoid bone drilling. Intraoperative hypotension and hypertension were designated as a decrease or increase in mean arterial pressure (MAP) of greater than 20% of baseline. Bradycardia and tachycardia were established as a decrease or increase in heart rate (HR), respectively, of greater than 20% of baseline. If bradycardia or hypotension occurred, the inhaled anesthetic (ie, desflurane or sevoflurane) was decreased by 25%. This decrease in the inhaled anesthetic was repeated and if hemodynamic parameters did not return to baseline, ephedrine 5 mg IV was administered every 3 minutes until a heart rate and blood pressure response was noted. If tachycardia or hypertension occurred, anesthetic levels were increased. This increase in the inhaled anesthetic was repeated if hemodynamic parameters did not return to normal. If the desired response was not achieved, esmolol 10-20 mg IV was given. The BIS value was recorded after each adjustment of the inhaled anesthetic in response to hemodynamic irregularities. BIS scores and hemodynamic parameters were recorded at the time of first incision, with mastoid drilling, and with any movement. If movement did occur, the BIS value was recorded and additional anesthetics were administered as stipulated above for a response to hypertension and tachycardia. At last suture placement (time 0), the anesthetic was discontinued and the orogastric tube was suctioned and removed. When appropriate, the patient was extubated. Time to eye opening and extubation were recorded, as well as duration of surgery and total anesthesia time. Immediate postoperative variables recorded included total PACU time, time until discharge readiness, incidence of nausea, retching and vomiting, severity scores for nausea and pain, and the incidence of rescue medications given for nausea and pain. Nausea and pain were assessed every 5 minutes in the PACU using a verbal analog scale (VAS), with 1 representing no pain or nausea and 10 representing severe symptoms. Stewart Recovery Scores11 were used to assess emergence from anesthesia in the PACU. Stewart recovery variables (consciousness, airway, movement) were evaluated at specific time intervals (on admission to PACU; at 5, 15, 30, 45, and 60 minutes; and on discharge from PACU). Anti-emetic rescue medication was given for nausea scores of 5 or greater, or if the patient had one or more episodes of emesis or retching within a 30 minute period. Ondansetron 4 mg IV was given initially and repeated in 10 minutes if needed. If nausea was still severe or if emesis continued, Tigan 200 mg was given rectally. Patients with pain scores of 5 or greater were given fentanyl 25 mcg IV, and this dose was repeated every 10 minutes until a score of less than 4 was achieved. Mild pain (less than 3) was treated with acetaminophen. After discharge from PACU, the incidence of vomiting and retching and severity of nausea (assessed by the same visual analog scale) were recorded. The time until first oral intake of liquid and solids, first voiding, and ability to walk without dizziness were also recorded. In addition, data re-
Jellish et al
Standard Anesthetic Technique for Middle Ear . . .
ing 2 analysis and paired sample t test as appropriate. A P value ⬍ 0.05 was considered statistically significant.
Table 1 Patient demographics
Male Female Age (y) Height (cm) Weight (kg) Day number of menstrual cycle Smoker History of PONV History of motion sickness
271
Sevoflurane group (n ⫽ 50)
Desflurane group (n ⫽ 50)
22 (44) 28 (56) 41.2 ⫾ 1.7 170.2 ⫾ 1.4 76.9 ⫾ 2.7 16.1 ⫾ 1.9
30 (60) 20 (40) 44.6 ⫾ 1.8 172.3 ⫾ 1.6 79.7 ⫾ 2.4 12.4 ⫾ 1.8
14 (28) 14 (28) 14 (28)
13 (26) 12 (24) 7 (14)
PONV, Postoperative nausea and vomiting.Values represented as mean ⫾ SEM. Values in parenthesis represent % of total. No significant differences noted.
garding the incidence of sore throat or hoarseness during the first 24 hours after discharge was also obtained. Cost analysis of anesthetics was done utilizing the formula PFTMC/2412d, published by Dion.12 The cost in dollars per case was calculated by employing the formula, where P ⫽ percent of vapor concentration, F ⫽ fresh gas flows in liters per minute, T ⫽ duration of anesthetic in minutes, M ⫽ molecular weight of the anesthetic gas (sevoflurane ⫽ 200.05 and desflurane ⫽ 168), C ⫽ cost of anesthetic in dollars per milliliter (sevoflurane ⫽ $0.38/mL and desflurane ⫽ $0.75 at our institution), and d ⫽ density of anesthetic gas in grams per milliliter.
Statistical Analysis Based on prior studies involving gynecological patient populations undergoing surgeries with similar incidences of PONV as middle ear procedures, the incidence of PONV with desflurane and sevoflurane was 80% and 50% respectively.13 Utilizing an a priori power analysis, a patient population of 100 (50 per study group) was appropriate for detection of a difference of 30% in PONV between desflurane and sevoflurane with a power of 0.9 and an ␣ ⫽ 0.05. Demographic variables were compared between groups us-
RESULTS Patient demographics are presented in Table 1. There were no statistically significant differences in gender, age, height, weight, smoking history, day number of menstrual cycle, or prior history of PONV or motion sickness. Total anesthetic and surgical times and times to eye opening and extubation were also similar (Table 2). No significant differences were observed in either HR or MAP during the intraoperative period. On average, intraoperative BIS scores were lower in the desflurane group compared to those receiving sevoflurane (Table 3). PACU heart rates were similar between groups while PACU MAPs were higher in patients receiving desflurane (Table 4). Emergence from anesthesia, as measured by Stewart scores, was similar in both groups. There were no significant differences between groups with respect to nausea and vomiting frequencies, pain scores, recovery scores, discharge readiness, and discharge times. Twenty-four-hour follow-up data is shown in Table 5. There were no differences noted between groups in overall incidence of nausea and vomiting, dizziness, sore throat, and hoarseness. Overall satisfaction scores (with the anesthetic technique) also showed no significant difference between the two groups. Finally, anesthetic cost (in US dollars per case) was found to be significantly higher in the desflurane group versus the sevoflurane group (15.40 ⫾ 1.45 vs 20.00 ⫾ 1.72, P ⫽ 0.043).
DISCUSSION Previous studies have demonstrated that total intravenous anesthesia (TIVA) using propofol/fentanyl or propofol/ remifentanil for otologic surgical procedures offers ideal intraoperative conditions and rapid emergence from anesthesia with reduced PONV.1,2 However, these anesthetic techniques are expensive and, if the procedure is prolonged, may be cost prohibitive. Newer short-acting inhalational anesthetics using sevoflurane or desflurane are less expen-
Table 2 Intraoperative data
Total anesthetic time (minutes) Total surgical time (minutes) Time to eye opening (minutes) Time to extubation (minutes) Incidence of movement under anesthesia
Sevoflurane group (n ⫽ 50)
Desflurane group (n ⫽ 50)
87.7 ⫾ 5.1 60.5 ⫾ 4.2 7.7 ⫾ 0.5 8.5 ⫾ 0.6 9 (18)
83.3 ⫾ 3.8 57.5 ⫾ 3.5 9.5 ⫾ 0.8 10.0 ⫾ 0.8 6 (12)
Values expressed as means ⫾ SEM. No significant differences noted.
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Table 3 Intraoperative BIS data
Baseline bispectral index (BIS) score Post-intubation BIS score 1 minute 5 minutes Post-incision BIS score 1 minute 5 minutes Post–bone drilling BIS score 1 minute 5 minutes BIS score at movement BIS score at last suture BIS score at extubation Average OR BIS numbers BIS numbers with PONV
Sevoflurane group (n ⫽ 50)
Desflurane group (n ⫽ 50)
95.2 ⫾ 0.6
95.3 ⫾ 0.5
37.7 ⫾ 1.5 43.0 ⫾ 1.5
40.0 ⫾ 1.8 39.6 ⫾ 1.4*
41.9 ⫾ 1.2 41.6 ⫾ 1.1
39.2 ⫾ 1.1 39.3 ⫾ 1.0
42.5 41.5 44.4 52.6 90.1 41.4 35.3
⫾ ⫾ ⫾ ⫾ ⫾ ⫾ ⫾
1.2 1.03 3.8 2.0 1.1 6.4 1.4
39.9 40.3 45.2 46.9 91.4 39.6 31.3
⫾ ⫾ ⫾ ⫾ ⫾ ⫾ ⫾
1.1* 1.2 6.5 2.3 1.1 5.6 1.1*
OR, Operating room; PONV, Postoperative nausea and vomiting.Values expressed as means ⫾ SEM. *Significance was defined as P ⬍ 0.05.
sive, simpler to utilize and offer similar intraoperative conditions as the TIVA techniques. This study demonstrates that both inhalational anesthetics produce similar intraoperative conditions and hemodynamics. Emergence from anesthesia was also similar with the two anesthetic techniques. This finding is different from other studies, which have
noted a faster emergence from anesthesia with desflurane.5,14,15 However, these studies examined prolonged exposure to these inhalational anesthetics (2-8 hrs). Total anesthetic times for the procedures in this study were under 90 minutes. Prolonged exposure to sevoflurane may produce accumulation of effect since the 90% decrement time
Table 4 Postanesthesia Care Unit (PACU) data Sevoflurane group (n ⫽ 50) PACU HR At admission to PACU At 30 minutes At 45 minutes At 60 minutes At discharge from PACU PACU MAP At admission to PACU At 30 minutes At 45 minutes At 60 minutes At discharge from PACU Vomiting frequency in PACU (%) Nausea frequency in PACU (%) Frequency of PONV rescue medication (%) PACU pain scores At admission to PACU At 30 minutes At 45 minutes At 60 minutes At discharge from PACU Discharge ready time from PACU Discharge time from PACU (minutes) Values expressed as means ⫾ SEM. *Significant difference was defined as P ⬍ 0.05.
85.32 76.16 73.90 73.19 71.27
⫾ ⫾ ⫾ ⫾ ⫾
2.1 2.1 1.8 2.0 2.0
95.72 ⫾ 1.6 94.76 ⫾ 1.7 93.73 ⫾ 1.7 94.03 ⫾ 1.7 93.89 ⫾ 1.5 8 (16) 23 (46) 22 (44) 2.3 3.1 3.2 3.5 3.4 17.4 80.4
⫾ ⫾ ⫾ ⫾ ⫾ ⫾ ⫾
0.5 0.4 0.4 0.3 0.3 3.0 5.0
Desflurane group (n ⫽ 50) 84.80 78.74 76.32 73.67 71.78
⫾ ⫾ ⫾ ⫾ ⫾
1.7 1.8 1.7 1.6 1.5
98.32 ⫾ 1.8 99.71 ⫾ 1.6* 100.70 ⫾ 1.6* 98.78 ⫾ 1.7 98.56 ⫾ 2.0* 7 (14) 25 (50) 21 (42) 1.9 2.7 3.0 2.9 2.6 20.8 81.3
⫾ ⫾ ⫾ ⫾ ⫾ ⫾ ⫾
0.4 0.4 0.3 0.3 0.3 3.3 4.3
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Standard Anesthetic Technique for Middle Ear . . .
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Table 5 24-Hour follow-up data Sevoflurane group (n ⫽ 50) Time to first void Time to first PO liquid Time to first PO solid Incidence of vomiting (%) Incidence of nausea (%) Incidence of dizziness (%) Incidence of sore throat (%) Incidence of hoarseness (%) Overall satisfaction score (1 ⫽ very dissatisfied, 10 ⫽ very satisfied)
209.9 135.4 697.4 21 30 23 28 9 8.50
⫾ 19.1 ⫾ 15.9 ⫾ 76.6 (42) (60) (46) (56) (18) ⫾ 0.3
Desflurane group (n ⫽ 50) 222.7 127.1 758.9 20 30 16 21 8 8.22
⫾ 28.0 ⫾ 13.2 ⫾ 79.3 (40) (60) (32) (42) (16) ⫾ 0.3
Values in parenthesis presented as a percent of total. No significant differences noted.
for sevoflurane increases significantly with anesthetics of greater than 120 minutes, while it remains the same for desflurane despite length of exposure.6 Short procedures would produce less of an effect on emergence from sevoflurane compared to longer procedures. Thus no difference in emergence was noted in the present study between patients who received sevoflurane and patients receiving desflurane. Intraoperative BIS data demonstrated that maintenance of a stable surgical field required patients receiving desflurane be titrated to a deeper level of anesthesia than patients who received sevoflurane. This is in agreement with other studies that have shown that patients receiving desflurane require a higher minimum alveolar concentration to prevent reaction to an irritating stimulus.16,17 Deep levels of intraoperative anesthesia with desflurane may also increase emergence times, which may explain our findings of similar emergence with desflurane and sevoflurane even though desflurane has a lower blood solubility, usually producing a more rapid emergence. Postoperative variables were again similar after both anesthetics. No differences in heart rates were noted. Patients receiving desflurane, however, had higher MAPs compared to those receiving sevoflurane. These higher pressures cannot be explained by differences in emergence since Stewart recovery scores were similar. In addition, pain was also similar and actually slightly less in the desflurane group. Higher PACU MAPs after desflurane anesthesia may be due to a greater incidence of emergence delirium noted in these patients.7 Several studies have reported less emesis or nausea with sevoflurane compared to desflurane.9,13,14 Most investigators have blamed the increased pungency and airway irritation of desflurane for the increased emesis. However, our study failed to demonstrate any difference in PONV between the two different anesthetic agents. Other studies have also failed to detect any difference in nausea and vomiting when comparing these inhalational anesthetics.5,18 It is probable that neither has any anti-emetic properties comparable to propofol. In fact, one recent study by Apfel et al19 demonstrated that a dose-response relationship exists
between inhalational agents and PONV, not observed with propofol. This PONV occurred in the early postoperative period (1-2 hours after surgery) and was not related to the use of N2O or opioids, other confounding factors linked with PONV.19 Differences in PONV noted between sevoflurane and desflurane in other studies may have occurred because of differences in patient populations (some used pediatric patients) or types of surgical populations studied (laparoscopic gynecological, knee arthroscopy, etc.).5,8,9 Further support for PONV being associated with exposure to inhalational anesthesia is noted from an examination of BIS values in patients who had PONV. Their BIS values were lower, on average, throughout surgery compared with patients who had no PONV.20 This observation has also been noted in the present study, where patients who had PONV had lower BIS values compared to patients without these symptoms. It suggests that maintaining patients on a deeper plane of anesthesia with inhalational agents increases their risk for PONV in the early PACU period. Finally, cost analysis of the two inhalational anesthetic techniques demonstrated that desflurane was approximately $5 more per anesthetic then sevoflurane. This differs from the results reported by Boldt et al,3 who found no differences in cost between isoflurane, desflurane, or sevoflurane anesthesia. In that study fresh gas flow rates did not differ between groups (similar to our study), but their method of calculating anesthetic costs was derived from weighing the vaporizors to determine gas usage versus using our calculation method. Our fresh gas flow rates of 2 to 3 liters/ minute may be higher than those typically used for desflurane anesthesia and may have adversely affected costs. However, the $15 to $20 per anesthesia is much less than the $69 per anesthetic noted for total intravenous anesthesia using propofol/reminfentanil.2 In conclusion, we found no true clinical differences between either desflurane or sevoflurane for middle ear otologic procedures. Both have a better emergence profile than isoflurane but produce no difference in hemodynamic variables, pain, PONV, or patient satisfaction. The slight cost
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preferences for sevoflurane may be artificial because of the fresh gas flows used for this study. We believe that either inhalational anesthetic may be used for otologic surgical procedures in patients who have no true emetogenic history, providing a significant cost advantage over TIVA. However, in patients with a history of previous PONV or motion sickness, a TIVA technique with propofol is the only anesthetic technique proven to reduce PONV after middle ear otologic surgery.1
REFERENCES 1. Jellish WS, Leonetti JP, Murdoch JR, et al. Propofol-based anesthesia as compared with standard anesthetic techniques for middle ear surgery. J Clin Anesth 1995;7:292– 6. 2. Jellish WS, Leonetti JP, Avramov A, et al. Remifentanil-based anesthesia versus a propofol technique for otologic surgical procedures. Otolaryngol Head Neck Surg 2000;122:222–7. 3. Boldt J, Jaun N, Kumle B, et al. Economic considerations of the use of new anesthetics: a comparison of propofol, sevoflurane, desflurane, and isoflurane. Anesth Anal 1998;86:504 –9. 4. Nathanson MH, Fredman B, Smith I, et al. Sevoflurane versus desflurane for outpatient anesthesia: a comparison of maintenance and recovery profiles. Anesth Anal 1995;81:1186 –90. 5. Naidu-Sjosvard K, Sjoberg F, Gupta A. Anaesthesia for videoarthroscopy of the knee: a comparison between desflurane and sevoflurane. Acta Anaesthesiol Scand 1998;42:464 –71. 6. Larsen B, Seitz A, Larsen R. Recovery of cognitive function after remifentanil-propofol anesthesia: a comparison with desflurane and sevoflurane anesthesia. Anesth Anal 2000;90:168 –74. 7. Welborn LG, Hannallah RS, Norden JM, et al. Comparison of emergence and recovery characteristics of sevoflurane, desflurane, and halothane in pediatric ambulatory patients. Anesth Anal 1996;83:917– 20.
8. Song D, Joshi GP, White PF. Fast-track eligibility after ambulatory anesthesia: a comparison of desflurane, sevoflurane, and propofol. Anesth Anal 1998;86:267–73. 9. Karlsen KL, Persson E, Wennberg E, et al. Anaesthesia, recovery and postoperative nausea and vomiting after breast surgery. A comparison between desflurane, sevoflurane and isoflurane anaesthesia. Acta Anaesthesiol Scand 2000;44:489 –93. 10. Rosow C, Manberg PJ. Bispectral index monitoring. Anesth Clin North America 2001;19:947– 66. 11. Stewart DJ. A simplified scoring system for the post-operative recovery room. Canadian Anaesth Soc J 1975;22:111–3. 12. Dion P. The cost of anaesthetic vapours. Can J Anaesth 1992;39:633. 13. Eriksson H, Korttila K. Recovery profile after desflurane with or without ondansetron compared with propofol in patients undergoing outpatient gynecological laparoscopy. Anesth Anal 1996;82:533– 8. 14. Heavner JE, Kage AD, Lin BK, et al. Recovery of elderly patients from two or more hours of desflurane or sevoflurane anesthesia. Br J Anaesth 2003;91:502– 6. 15. Eger E, Bowland T, Ionescu P, et al. Recovery and kinetic characteristics of desflurane and sevoflurane in volunteers after 8h exposure, including kinetics of degradation products. Anesthesiology 1997;87: 517–26. 16. Klock PA, Czeslick EG, Klafta JM, et al. The effect of sevoflurane and desflurane on upper airway reactivity. Anesthesiology 2001;94:963–7. 17. Vanacker B, Van Geldre L. A randomized study of the efficacy and recovery of remifentanil-based and alfentanil anaesthesia with desflurane or sevoflurane for gynecological surgery. Acta Anaesthesiol Belgica 2002;53:21– 6. 18. Song D, Whitten CW, White PF, et al. Antiemetic activity of propofol after sevoflurane and desflurane anesthesia for outpatient laparoscopic cholecystectomy. Anesthesiology 1998;89:838 – 43. 19. Apfel CC, Kianke P, Katz MH, et al. Volatile anaesthetics may be the main cause of early but not delayed postoperative vomiting: a randomized controlled trial of factorial design. Br J Anaesth 2002;88: 659 – 68. 20. Nelskyla KA, Yli-Hankala AM, Puro PH, et al. Sevoflurane titration using bispectral index decreases postoperative vomiting in phase II recovery after ambulatory surgery. Anesth Anal 2001;92:1165–9.
Standard Anesthetic Technique for Middle Ear Surgical Procedures: A Comparison of Desflurane and Sevoflurane W. Scott Jellish, MD, PhD, Kevin Owen, MD, Steven Edelstein, MD, Elaine Fluder, RN, MSN, and John P. Leonetti, MD, Maywood, Illinois OBJECTIVE: This study was designed to compare desflurane and sevoflurane anesthesia for middle ear microsurgery. STUDY DESIGN: One hundred healthy adults undergoing middle ear surgery were assigned to receive either desflurane or sevoflurane as their anesthetic. Intraoperative hemodynamics and BIS numbers were recorded. Hemodynamics, pain, nausea/vomiting, discharge readiness, and other parameters were compared postoperatively and 24 hours later. RESULTS: No intraoperative differences were noted except in BIS scores which trended lower with desflurane. PACU blood pressures were higher after desflurane but pain scores, nausea/ vomiting, rescue anti-emetics, recovery scores, and discharge times were similar. A significant difference was noted in anesthetic costs (desflurane ⬎ sevoflurane), and in patients with the lowest BIS scores associated with more nausea/vomiting. CONCLUSIONS: Both anesthetics may be used for ototic surgery but propofol anesthesia should still be considered in patients with a history of emetic sequelae. SIGNIFICANCE: Short-acting inhalational anesthetics produce excellent operating conditions and reduce costs for otologic surgery. © 2005 American Academy of Otolaryngology–Head and Neck Surgery Foundation, Inc. All rights reserved.
M
iddle ear surgical procedures require an anesthetic technique that produces a motionless, bloodless surgical field and minimal postoperative nausea and vomiting (PONV). In addition, the need for intraoperative monitoring of the facial nerve during surgery requires that the patient remain unparalyzed during the most stimulating portions of From the Departments of Anesthesiology (Drs Jellish, Owen, and Edelstein and Ms Fluder) and Otolaryngology (Dr Leonetti), Loyola University Medical Center. Presented at the Annual Meeting of the American Academy of Otolaryngology–Head and Neck Surgery, New York, NY, September 19-22, 2004.
the surgery. Therefore, the anesthesiologist must use an anesthetic technique that provides a sufficiently deep level of anesthesia with minimal intraoperative movement, rapid emergence, and decreased postsurgical morbidity. Previously, our group evaluated a propofol-based anesthetic technique and compared this to a standard inhalational anesthetic for middle ear surgery and concluded that the propofol technique produced acceptable perioperative conditions and reduced the incidence of PONV.1 Remifentanil-based anesthesia with low-dose propofol was also compared to a propofol-based technique and was found to provide better hemodynamic control, less movement, and faster emergence, yet with the same anti-emetic effect.2 However, the costs associated with these intravenous (IV) techniques are much higher and total propofol techniques may increase time to emergence and extubations.3 Desflurane is a volatile anesthetic agent with a low solubility that allows for rapid induction and fast emergence from anesthesia. Sevoflurane, another volatile anesthetic, also has a low solubility, making it a good agent for rapid induction and fast emergence from anesthesia. In addition, this anesthetic produces much less airway irritability and may produce less coughing, breath holding, and postoperative complications. Studies comparing desflurane and sevoflurane have shown that desflurane leads to a more rapid emergence and shorter time to extubation with faster cognitive and psychomotor recovery, but a greater incidence of postoperative sore throat and a higher incidence of postoperative agitation and excitement.4-7 However, there Reprint requests: W. Scott Jellish, MD, PhD, Department of Anesthesiology, Loyola University Medical Center, 2160 S. First Avenue, Maywood, IL 60153. E-mail address: [email protected].
0194-5998/$30.00 © 2005 American Academy of Otolaryngology–Head and Neck Surgery Foundation, Inc. All rights reserved. doi:10.1016/j.otohns.2005.04.011
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has been conflicting data in regard to the incidence of postoperative morbidity after using these two anesthetics.8-9 No prior study has compared the efficacy, postoperative morbidities, and intraoperative variables of these two inhalation agents for middle ear surgeries. This study compares the perioperative effect of these two agents in patients undergoing middle ear surgical procedures and attempts to determine if one agent is superior to the other in the incidence of postoperative morbidities, recovery parameters, and cost effectiveness.
METHODS After Institutional Review Board approval, 100 healthy adult patients (ages 18-65) undergoing elective middle ear surgery were consented and enrolled into the study. These surgeries included stapedectomies, mastoidectomies, ossiculoplasties, endolymphatic sac decompressions, and tympanoplasties. Patients were excluded from the study if they had medical conditions known to increase the incidence of nausea and vomiting, with delayed gastric emptying (diabetes, chronic cholecystitis, neuropathy, neuromuscular disease), pregnancy, or obesity (body mass index ⬎ 30). Bispectral index (BIS) was used to titrate each patient to a similar anesthetic depth denoted by a BIS number of approximately 40. This level of hypnosis is associated with a lower incidence of movement and implicit recall as compared to standard anesthetic titration techniques.10 The patients were equally divided and randomly assigned into one of two groups. Group 1 patients received an anesthetic composed of propofol 2 mg/kg IV for induction of anesthesia, followed by maintenance anesthesia using desflurane 6%–9% end-tidal (ET) at fresh gas flows of 2 to 3 liters/minute in a 50% air/oxygen mixture. Patients in Group 2, again, received propofol 2 mg/kg IV for induction, followed by sevoflurane 2%–3% ET at similar fresh gas flows. Both groups received midazolam 2 mg IV prior to initiation of anesthesia. After induction, both groups received fentanyl 2 mcg/kg IV, and atracurium 0.5 mg/kg IV to facilitate intubation. Neither group received additional muscle relaxant or neuromuscular reversal drugs. The patients had an orogastric tube placed to decompress the stomach prior to the start of the surgery. During the preinduction period, EEG gel surface adhesive electrodes were placed in a fronto-occipital montage pattern over the cortex. BIS monitoring began 1 minute prior to induction of anesthesia with the patient quietly resting on the operating table to establish a baseline. BIS monitoring continued throughout the remainder of the surgery and was discontinued after emergence from anesthesia and prior to the patient’s being brought to the postanesthesia care unit (PACU). Hemodynamic responses to laryngoscopy and intubation were recorded, as was the response to surgical incision and
mastoid bone drilling. Intraoperative hypotension and hypertension were designated as a decrease or increase in mean arterial pressure (MAP) of greater than 20% of baseline. Bradycardia and tachycardia were established as a decrease or increase in heart rate (HR), respectively, of greater than 20% of baseline. If bradycardia or hypotension occurred, the inhaled anesthetic (ie, desflurane or sevoflurane) was decreased by 25%. This decrease in the inhaled anesthetic was repeated and if hemodynamic parameters did not return to baseline, ephedrine 5 mg IV was administered every 3 minutes until a heart rate and blood pressure response was noted. If tachycardia or hypertension occurred, anesthetic levels were increased. This increase in the inhaled anesthetic was repeated if hemodynamic parameters did not return to normal. If the desired response was not achieved, esmolol 10-20 mg IV was given. The BIS value was recorded after each adjustment of the inhaled anesthetic in response to hemodynamic irregularities. BIS scores and hemodynamic parameters were recorded at the time of first incision, with mastoid drilling, and with any movement. If movement did occur, the BIS value was recorded and additional anesthetics were administered as stipulated above for a response to hypertension and tachycardia. At last suture placement (time 0), the anesthetic was discontinued and the orogastric tube was suctioned and removed. When appropriate, the patient was extubated. Time to eye opening and extubation were recorded, as well as duration of surgery and total anesthesia time. Immediate postoperative variables recorded included total PACU time, time until discharge readiness, incidence of nausea, retching and vomiting, severity scores for nausea and pain, and the incidence of rescue medications given for nausea and pain. Nausea and pain were assessed every 5 minutes in the PACU using a verbal analog scale (VAS), with 1 representing no pain or nausea and 10 representing severe symptoms. Stewart Recovery Scores11 were used to assess emergence from anesthesia in the PACU. Stewart recovery variables (consciousness, airway, movement) were evaluated at specific time intervals (on admission to PACU; at 5, 15, 30, 45, and 60 minutes; and on discharge from PACU). Anti-emetic rescue medication was given for nausea scores of 5 or greater, or if the patient had one or more episodes of emesis or retching within a 30 minute period. Ondansetron 4 mg IV was given initially and repeated in 10 minutes if needed. If nausea was still severe or if emesis continued, Tigan 200 mg was given rectally. Patients with pain scores of 5 or greater were given fentanyl 25 mcg IV, and this dose was repeated every 10 minutes until a score of less than 4 was achieved. Mild pain (less than 3) was treated with acetaminophen. After discharge from PACU, the incidence of vomiting and retching and severity of nausea (assessed by the same visual analog scale) were recorded. The time until first oral intake of liquid and solids, first voiding, and ability to walk without dizziness were also recorded. In addition, data re-
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Standard Anesthetic Technique for Middle Ear . . .
ing 2 analysis and paired sample t test as appropriate. A P value ⬍ 0.05 was considered statistically significant.
Table 1 Patient demographics
Male Female Age (y) Height (cm) Weight (kg) Day number of menstrual cycle Smoker History of PONV History of motion sickness
271
Sevoflurane group (n ⫽ 50)
Desflurane group (n ⫽ 50)
22 (44) 28 (56) 41.2 ⫾ 1.7 170.2 ⫾ 1.4 76.9 ⫾ 2.7 16.1 ⫾ 1.9
30 (60) 20 (40) 44.6 ⫾ 1.8 172.3 ⫾ 1.6 79.7 ⫾ 2.4 12.4 ⫾ 1.8
14 (28) 14 (28) 14 (28)
13 (26) 12 (24) 7 (14)
PONV, Postoperative nausea and vomiting.Values represented as mean ⫾ SEM. Values in parenthesis represent % of total. No significant differences noted.
garding the incidence of sore throat or hoarseness during the first 24 hours after discharge was also obtained. Cost analysis of anesthetics was done utilizing the formula PFTMC/2412d, published by Dion.12 The cost in dollars per case was calculated by employing the formula, where P ⫽ percent of vapor concentration, F ⫽ fresh gas flows in liters per minute, T ⫽ duration of anesthetic in minutes, M ⫽ molecular weight of the anesthetic gas (sevoflurane ⫽ 200.05 and desflurane ⫽ 168), C ⫽ cost of anesthetic in dollars per milliliter (sevoflurane ⫽ $0.38/mL and desflurane ⫽ $0.75 at our institution), and d ⫽ density of anesthetic gas in grams per milliliter.
Statistical Analysis Based on prior studies involving gynecological patient populations undergoing surgeries with similar incidences of PONV as middle ear procedures, the incidence of PONV with desflurane and sevoflurane was 80% and 50% respectively.13 Utilizing an a priori power analysis, a patient population of 100 (50 per study group) was appropriate for detection of a difference of 30% in PONV between desflurane and sevoflurane with a power of 0.9 and an ␣ ⫽ 0.05. Demographic variables were compared between groups us-
RESULTS Patient demographics are presented in Table 1. There were no statistically significant differences in gender, age, height, weight, smoking history, day number of menstrual cycle, or prior history of PONV or motion sickness. Total anesthetic and surgical times and times to eye opening and extubation were also similar (Table 2). No significant differences were observed in either HR or MAP during the intraoperative period. On average, intraoperative BIS scores were lower in the desflurane group compared to those receiving sevoflurane (Table 3). PACU heart rates were similar between groups while PACU MAPs were higher in patients receiving desflurane (Table 4). Emergence from anesthesia, as measured by Stewart scores, was similar in both groups. There were no significant differences between groups with respect to nausea and vomiting frequencies, pain scores, recovery scores, discharge readiness, and discharge times. Twenty-four-hour follow-up data is shown in Table 5. There were no differences noted between groups in overall incidence of nausea and vomiting, dizziness, sore throat, and hoarseness. Overall satisfaction scores (with the anesthetic technique) also showed no significant difference between the two groups. Finally, anesthetic cost (in US dollars per case) was found to be significantly higher in the desflurane group versus the sevoflurane group (15.40 ⫾ 1.45 vs 20.00 ⫾ 1.72, P ⫽ 0.043).
DISCUSSION Previous studies have demonstrated that total intravenous anesthesia (TIVA) using propofol/fentanyl or propofol/ remifentanil for otologic surgical procedures offers ideal intraoperative conditions and rapid emergence from anesthesia with reduced PONV.1,2 However, these anesthetic techniques are expensive and, if the procedure is prolonged, may be cost prohibitive. Newer short-acting inhalational anesthetics using sevoflurane or desflurane are less expen-
Table 2 Intraoperative data
Total anesthetic time (minutes) Total surgical time (minutes) Time to eye opening (minutes) Time to extubation (minutes) Incidence of movement under anesthesia
Sevoflurane group (n ⫽ 50)
Desflurane group (n ⫽ 50)
87.7 ⫾ 5.1 60.5 ⫾ 4.2 7.7 ⫾ 0.5 8.5 ⫾ 0.6 9 (18)
83.3 ⫾ 3.8 57.5 ⫾ 3.5 9.5 ⫾ 0.8 10.0 ⫾ 0.8 6 (12)
Values expressed as means ⫾ SEM. No significant differences noted.
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Table 3 Intraoperative BIS data
Baseline bispectral index (BIS) score Post-intubation BIS score 1 minute 5 minutes Post-incision BIS score 1 minute 5 minutes Post–bone drilling BIS score 1 minute 5 minutes BIS score at movement BIS score at last suture BIS score at extubation Average OR BIS numbers BIS numbers with PONV
Sevoflurane group (n ⫽ 50)
Desflurane group (n ⫽ 50)
95.2 ⫾ 0.6
95.3 ⫾ 0.5
37.7 ⫾ 1.5 43.0 ⫾ 1.5
40.0 ⫾ 1.8 39.6 ⫾ 1.4*
41.9 ⫾ 1.2 41.6 ⫾ 1.1
39.2 ⫾ 1.1 39.3 ⫾ 1.0
42.5 41.5 44.4 52.6 90.1 41.4 35.3
⫾ ⫾ ⫾ ⫾ ⫾ ⫾ ⫾
1.2 1.03 3.8 2.0 1.1 6.4 1.4
39.9 40.3 45.2 46.9 91.4 39.6 31.3
⫾ ⫾ ⫾ ⫾ ⫾ ⫾ ⫾
1.1* 1.2 6.5 2.3 1.1 5.6 1.1*
OR, Operating room; PONV, Postoperative nausea and vomiting.Values expressed as means ⫾ SEM. *Significance was defined as P ⬍ 0.05.
sive, simpler to utilize and offer similar intraoperative conditions as the TIVA techniques. This study demonstrates that both inhalational anesthetics produce similar intraoperative conditions and hemodynamics. Emergence from anesthesia was also similar with the two anesthetic techniques. This finding is different from other studies, which have
noted a faster emergence from anesthesia with desflurane.5,14,15 However, these studies examined prolonged exposure to these inhalational anesthetics (2-8 hrs). Total anesthetic times for the procedures in this study were under 90 minutes. Prolonged exposure to sevoflurane may produce accumulation of effect since the 90% decrement time
Table 4 Postanesthesia Care Unit (PACU) data Sevoflurane group (n ⫽ 50) PACU HR At admission to PACU At 30 minutes At 45 minutes At 60 minutes At discharge from PACU PACU MAP At admission to PACU At 30 minutes At 45 minutes At 60 minutes At discharge from PACU Vomiting frequency in PACU (%) Nausea frequency in PACU (%) Frequency of PONV rescue medication (%) PACU pain scores At admission to PACU At 30 minutes At 45 minutes At 60 minutes At discharge from PACU Discharge ready time from PACU Discharge time from PACU (minutes) Values expressed as means ⫾ SEM. *Significant difference was defined as P ⬍ 0.05.
85.32 76.16 73.90 73.19 71.27
⫾ ⫾ ⫾ ⫾ ⫾
2.1 2.1 1.8 2.0 2.0
95.72 ⫾ 1.6 94.76 ⫾ 1.7 93.73 ⫾ 1.7 94.03 ⫾ 1.7 93.89 ⫾ 1.5 8 (16) 23 (46) 22 (44) 2.3 3.1 3.2 3.5 3.4 17.4 80.4
⫾ ⫾ ⫾ ⫾ ⫾ ⫾ ⫾
0.5 0.4 0.4 0.3 0.3 3.0 5.0
Desflurane group (n ⫽ 50) 84.80 78.74 76.32 73.67 71.78
⫾ ⫾ ⫾ ⫾ ⫾
1.7 1.8 1.7 1.6 1.5
98.32 ⫾ 1.8 99.71 ⫾ 1.6* 100.70 ⫾ 1.6* 98.78 ⫾ 1.7 98.56 ⫾ 2.0* 7 (14) 25 (50) 21 (42) 1.9 2.7 3.0 2.9 2.6 20.8 81.3
⫾ ⫾ ⫾ ⫾ ⫾ ⫾ ⫾
0.4 0.4 0.3 0.3 0.3 3.3 4.3
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Table 5 24-Hour follow-up data Sevoflurane group (n ⫽ 50) Time to first void Time to first PO liquid Time to first PO solid Incidence of vomiting (%) Incidence of nausea (%) Incidence of dizziness (%) Incidence of sore throat (%) Incidence of hoarseness (%) Overall satisfaction score (1 ⫽ very dissatisfied, 10 ⫽ very satisfied)
209.9 135.4 697.4 21 30 23 28 9 8.50
⫾ 19.1 ⫾ 15.9 ⫾ 76.6 (42) (60) (46) (56) (18) ⫾ 0.3
Desflurane group (n ⫽ 50) 222.7 127.1 758.9 20 30 16 21 8 8.22
⫾ 28.0 ⫾ 13.2 ⫾ 79.3 (40) (60) (32) (42) (16) ⫾ 0.3
Values in parenthesis presented as a percent of total. No significant differences noted.
for sevoflurane increases significantly with anesthetics of greater than 120 minutes, while it remains the same for desflurane despite length of exposure.6 Short procedures would produce less of an effect on emergence from sevoflurane compared to longer procedures. Thus no difference in emergence was noted in the present study between patients who received sevoflurane and patients receiving desflurane. Intraoperative BIS data demonstrated that maintenance of a stable surgical field required patients receiving desflurane be titrated to a deeper level of anesthesia than patients who received sevoflurane. This is in agreement with other studies that have shown that patients receiving desflurane require a higher minimum alveolar concentration to prevent reaction to an irritating stimulus.16,17 Deep levels of intraoperative anesthesia with desflurane may also increase emergence times, which may explain our findings of similar emergence with desflurane and sevoflurane even though desflurane has a lower blood solubility, usually producing a more rapid emergence. Postoperative variables were again similar after both anesthetics. No differences in heart rates were noted. Patients receiving desflurane, however, had higher MAPs compared to those receiving sevoflurane. These higher pressures cannot be explained by differences in emergence since Stewart recovery scores were similar. In addition, pain was also similar and actually slightly less in the desflurane group. Higher PACU MAPs after desflurane anesthesia may be due to a greater incidence of emergence delirium noted in these patients.7 Several studies have reported less emesis or nausea with sevoflurane compared to desflurane.9,13,14 Most investigators have blamed the increased pungency and airway irritation of desflurane for the increased emesis. However, our study failed to demonstrate any difference in PONV between the two different anesthetic agents. Other studies have also failed to detect any difference in nausea and vomiting when comparing these inhalational anesthetics.5,18 It is probable that neither has any anti-emetic properties comparable to propofol. In fact, one recent study by Apfel et al19 demonstrated that a dose-response relationship exists
between inhalational agents and PONV, not observed with propofol. This PONV occurred in the early postoperative period (1-2 hours after surgery) and was not related to the use of N2O or opioids, other confounding factors linked with PONV.19 Differences in PONV noted between sevoflurane and desflurane in other studies may have occurred because of differences in patient populations (some used pediatric patients) or types of surgical populations studied (laparoscopic gynecological, knee arthroscopy, etc.).5,8,9 Further support for PONV being associated with exposure to inhalational anesthesia is noted from an examination of BIS values in patients who had PONV. Their BIS values were lower, on average, throughout surgery compared with patients who had no PONV.20 This observation has also been noted in the present study, where patients who had PONV had lower BIS values compared to patients without these symptoms. It suggests that maintaining patients on a deeper plane of anesthesia with inhalational agents increases their risk for PONV in the early PACU period. Finally, cost analysis of the two inhalational anesthetic techniques demonstrated that desflurane was approximately $5 more per anesthetic then sevoflurane. This differs from the results reported by Boldt et al,3 who found no differences in cost between isoflurane, desflurane, or sevoflurane anesthesia. In that study fresh gas flow rates did not differ between groups (similar to our study), but their method of calculating anesthetic costs was derived from weighing the vaporizors to determine gas usage versus using our calculation method. Our fresh gas flow rates of 2 to 3 liters/ minute may be higher than those typically used for desflurane anesthesia and may have adversely affected costs. However, the $15 to $20 per anesthesia is much less than the $69 per anesthetic noted for total intravenous anesthesia using propofol/reminfentanil.2 In conclusion, we found no true clinical differences between either desflurane or sevoflurane for middle ear otologic procedures. Both have a better emergence profile than isoflurane but produce no difference in hemodynamic variables, pain, PONV, or patient satisfaction. The slight cost
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preferences for sevoflurane may be artificial because of the fresh gas flows used for this study. We believe that either inhalational anesthetic may be used for otologic surgical procedures in patients who have no true emetogenic history, providing a significant cost advantage over TIVA. However, in patients with a history of previous PONV or motion sickness, a TIVA technique with propofol is the only anesthetic technique proven to reduce PONV after middle ear otologic surgery.1
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