- Email: [email protected]
Epidural fentanyl speeds the onset of sensory block during epidural lidocaine anesthesia
Epidural Fentanyl Speeds the Onset of Sensory Block During Epidural Lidocaine Anesthesia Chen-Hwan Cherng, M.D., D.M.Sc., Chih-Shung Wong, M.D., Ph.D., and Shung-Tai Ho, M.D. Background and Objectives: Shortening the onset time of sensory block is a practical goal to improve the quality of epidural anesthesia. The addition of fentanyl to a local anesthetic solution is widely used during epidural anesthesia. This randomized double-blind study examined the onset time of sensory block during epidural lidocaine anesthesia with and without added fentanyl to the epidural solution. Methods: Thirty-six young male patients undergoing knee arthroscopy were randomly allocated into 3 groups of 12 patients each: epidural fentanyl (EF, epidural administration of 17 mL of 2% lidocaine plus 100 g fentanyl and followed by intravenous (IV) injection of 2 mL of normal saline); IV fentanyl (IF, epidural administration of 17 mL of 2% lidocaine plus 2 mL of normal saline and followed by IV injection of 100 g of fentanyl); and control (C, epidural administration of 17 mL of 2% lidocaine plus 2 mL of normal saline and followed by IV injection of 2 mL of normal saline). The sensory block was assessed by pinprick method. The hemodynamic changes, postepidural shivering, and side effects of epidural fentanyl were also recorded. Results: There was no difference in the distribution of age, weight, and height among the 3 groups. The onset time of sensory block up to T10 dermatome was significantly more rapid in the EF group (8.3 ⫾ 3.7 minutes) than that of the IF group (13.1 ⫾ 4.2 minutes, P ⬍ .05) or C group (14.2 ⫾ 5.4 minutes, P ⬍ .05). The upper level of sensory block was also significantly higher in the EF group. Although the incidence of shivering was lower in the EF group, this did not reach statistical significance. Postepidural arterial blood pressures and heart rates were no different among the 3 groups. No nausea, vomiting, pruritus, respiratory depression, urinary retention, or hypotension were observed in any patients. Conclusion: Epidural injection of the mixture of 100 g fentanyl and 2% lidocaine solution accelerated the onset of sensory block during epidural lidocaine anesthesia without increased side effects. Reg Anesth Pain Med 2001;26:523-526. Key Words:
Epidural, Fentanyl, Lidocaine, Onset.
T
he speed of onset of epidural anesthesia is slower than spinal anesthesia. The addition of fentanyl to the local anesthetic solution is widely used in epidural anesthesia.1,2 Epidural fentanyl has been shown to shorten the onset time of anesthesia when used with epidural bupivacaine and mepivacaine.3,4 Other investigators have reported no change in the onset of anesthesia with the addition of fentanyl to epidural mepivacaine.5 There are no data for fentanyl’s impact on the latency of lidocaine epidural anesthesia. The purpose of this study is to examine the effect of epidural fentanyl on the From the Department of Anesthesiology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan. Accepted for publication July 9, 2001. Reprint requests: Chen-Hwan Cherng, M.D., D.M.Sc., 7F, No. 13, Lane 61, Won-Shou Road, Mu-Cha, 116, Taipei, Taiwan. E-mail: [email protected] © 2001 by the American Society of Regional Anesthesia and Pain Medicine. 1098-7339/01/2606-0013$35.00/0 doi:10.1053/rapm.2001.27852
onset time of sensory block during epidural lidocaine anesthesia.
Methods This was a randomized, double-blind, prospective study. After approval from the human research review committee of our institute, informed consent from each patient was obtained. Thirty-six young (⬃20 to 22 years old) male patients, American Society of Anesthesiologists (ASA) physical status I, scheduled for knee arthroscopy were included. The patients were randomly allocated into 3 groups: epidural fentanyl (EF), intravenous fentanyl (IF), and control (C) groups, with 12 patients in each group. The patients were monitored with electrocardiogram, arterial blood pressure, heart rate, and pulse oximetry during surgery. With patients in the left lateral decubitus position, epidural catheters were inserted at L3-4 interspace and advanced 5 cm into the space. A test dose of 3 mL of 2% lidocaine (ASTRA, So¨derta¨lje, Sweden) containing 1:200,000
Regional Anesthesia and Pain Medicine, Vol 26, No 6 (November–December), 2001: pp 523–526
523
524
Regional Anesthesia and Pain Medicine Vol. 26 No. 6 November–December 2001
Table 1. Demographic Data of the Three Groups
Age (yr) Weight (kg) Height (cm)
EF (n ⫽ 12)
IF (n ⫽ 12)
C (n ⫽ 12)
22.1 ⫾ 3.1 69.1 ⫾ 6.4 169.8 ⫾ 3.6
21.7 ⫾ 1.8 70.9 ⫾ 4.9 171.2 ⫾ 3.2
22.2 ⫾ 1.7 68.4 ⫾ 5.8 171.0 ⫾ 5.1
NOTE. Data ⫽ mean ⫾ SD.
epinephrine (freshly added) was administered to minimize development of intrathecal or intravenous (IV) injection. Three minutes later, the patients of group EF received the epidural administration of 17 mL of 2% lidocaine (containing 1:200,000 epinephrine) plus 100 g (2 mL) of fentanyl, followed by IV injection of 2 mL of normal saline. The patients of group IF received the epidural administration of 17 mL of 2% lidocaine (containing 1:200,000 epinephrine) plus 2 mL of normal saline, followed by an IV injection of 100 g (2 mL) of fentanyl. The patients of group C received the epidural administration of 17 mL of 2% lidocaine (containing 1:200,000 epinephrine) plus 2 mL of normal saline along with an IV injection of 2 mL of normal saline. The speed of epidural lidocaine administration was consistent in all groups, with a rate of 3 mL/10 s. The sensory block was assessed by pinprick method at 2.5-minute intervals for 30 minutes. Pinprick sensation was examined using a 21-gauge needle in a cephalad to caudal fashion along the left anterior axillary line by a blinded observer. The latency of block was defined as the time from epidural injection to the occurrence of sensory block at the T10 dermatome. The upper level of sensory block was also recorded. Arterial blood pressure and heart rate were measured every 2.5 minutes after epidural injection. Hypotension (systolic blood pressure ⬍ 100 mm Hg or a decrease of more than 30% from baseline) was treated with 5 mg of IV ephedrine as needed. Side effects such as nausea, vomiting, pruritus, respiratory depression, or shivering were recorded during surgery, and difficulty in micturition was also recorded postoperatively. The pH value of the 2 lidocaine solutions used in this study were determined by a pH meter. The results were expressed as mean ⫾ SD or median (range) for the level of sensory block. The pH of the local anesthetic solutions were analyzed by Student’s t-test. The difference of onset times was analyzed using analysis of variance (ANOVA) and the Student-Newman-Keuls test for posthoc comparison. The upper levels of sensory block were compared using the Kruskal-Wallis test and the Dunn’s multiple comparison procedure for posthoc comparison. The incidences of side effects among
groups were analyzed by chi-squared test. P ⬍ .05 was considered significant.
Results The three study groups were similar in age, weight, and height (Table 1). The pH of the 2 lidocaine solutions was no different: 6.61 ⫾ 0.02 (n ⫽ 3) in the 17 ml of 2% lidocaine containing 1:200,000 epinephrine plus 100 g (2 mL) of fentanyl, and 6.63 ⫾ 0.03 (n ⫽ 3) in the 17 ml of 2% lidocaine containing 1:200,000 epinephrine plus 2 mL of normal saline. The anesthetic characteristics of the 3 groups are shown in Table 2. The onset time of sensory block up to the T10 dermatome was significantly more rapid in the EF group than in the IF and C groups. The upper level of sensory block was significantly higher in the EF group than in the IF and C groups. The incidence of shivering in the EF group (3 of 12) was lower than that in the IF (5 of 12) and C groups (8 of 12); however, the difference was not significant. The changes of arterial blood pressure and heart rate were no different among the 3 groups. Nausea, vomiting, pruritus, and respiratory depression were not observed in any patients. No patient required urinary catheterization postoperatively.
Discussion The results of the present study show that addition of 100 g fentanyl to 2% epidural lidocaine solution accelerates the onset of the sensory block. The mechanisms by which fentanyl speeds the onset of sensory block are not clear. Alkalinization of the local anesthetic solutions is known to shorten the onset time of sensory block.6 The pH values of the 2 lidocaine solutions used in this study, fentanyl–lidocaine and normal saline–lidocaine solutions, were not different. Therefore, the pH changes did not account for this finding. A synergistic interaction between lidocaine and opioids with epidural administration has been reported.7 It appears that lidocaine and opioids exert their independent action via separate and distinct mechanisms. Lidocaine blocks impulses by inhibit-
Table 2. Anesthetic Characteristics of the Three Groups EF (n ⫽ 12)
IF (n ⫽ 12)
C (n ⫽ 12)
Onset time of sensory block 8.3 ⫾ 3.7* 13.1 ⫾ 4.2 14.2 ⫾ 5.4 to T10 dermatome (min) Upper level of sensory block T6 (3-10)* T8 (6-10) T8 (5-10) NOTE. Data ⫽ mean ⫾ SD or median (range). *P ⬍ .05 v IF and C groups.
Epidural Fentanyl and Lidocaine
ing sodium channels, while opioids act on the opioid receptors to produce an inhibitory effect on intracellular second messengers. In fact, lidocaine blocks the sodium channels, and also affects synaptic transmission. Kirota et al.8 reported that lidocaine dose-dependently inhibited the cyclic adenosine monophosphate formation in Chinese hamster ovary cells. Moreover, Li et al.9 showed that lidocaine inhibited both substance P binding and substance P– evoked increases in intracellular calcium. In contrast, opioids interact with opioid receptors either pre- or postsynaptically to exert an inhibitory effect on the neuronal transmission.10 In addition, opioids can also open potassium channels, which results in membrane hyperpolarization and decreased neuronal excitability.11 Therefore, the combination of local anesthetics and opioids may effectively inhibit multiple areas of neuronal excitability. Another possible mechanism of fentanyl accelerating the onset of epidural lidocaine is the local anesthetic effect of fentanyl. Meperidine has been reported as a sole agent for spinal anesthesia.12 Furthermore, unilateral analgesia after injection of fentanyl near the lumbosacral plexus was also reported,13 and a local anesthetic action of fentanyl was proposed. In electrophysiological studies, Gissen et al.14 found that perineural fentanyl and sufentanil inhibited the action potential of A and C fibers, and naloxone pretreatment did not prevent this inhibitory effect. Similarly, Power et al.15 showed that fentanyl blocked the nerve conduction of A and C fibers, and naloxone did not prevent this inhibitory effect. These results suggested that fentanyl may have some local anesthetic action that is not mediated via the opioid receptors. Compared with the C and IF groups, the upper level of sensory block was higher in the EF group. This finding was consistent with a previous report that epidural fentanyl enhanced the spread of sensory analgesia during bupivacaine epidural analgesia.16 A synergism of opioids and local anesthetics was proposed. The primary site of action of epidural fentanyl remains controversial; both spinal11,16 and supraspinal17 sites of action were proposed. Epidural fentanyl exerts its spinal effect on the dorsal horn of the spinal cord, where it binds to opioid receptors.18 Epidural fentanyl may also exert a supraspinal action by distribution from systemic absorption and by intrathecal cephalad spread. From the results of the present study, the IF group had no effect on either the onset time or the upper level of sensory block of lidocaine epidural anesthesia. This finding suggests that, in this study, fentanyl acted primarily at a spinal level. Shivering during epidural anesthesia has been reported,19 and epidural fentanyl has been used to
•
Cherng et al.
525
reduce shivering during epidural anesthesia.20 Our results showed that the frequency of shivering in the EF group was lower than that of the C and IF groups, though this difference was not statistically significant. In our study, side effects such as nausea, vomiting, pruritus, respiratory depression, urinary retention, and hypotension were not observed. It could be caused by the moderate doses of epidural medications used or by the young age of the patients in the study. It is known that side effects of intrathecal morphine, such as nausea/vomiting or difficulty with micturition, are less frequent in younger patients than in older patients.21 In conclusion, addition of 100 g fentanyl to 2% lidocaine (containing 1:200,000 epinephrine) shortened the onset time of sensory block during epidural anesthesia without increased side effects.
References 1. King MJ, Bowden MI, Cooper GM. Epidural fentanyl and 0.5% bupivacaine for elective caesarean section. Anaesthesia 1990;45:285-288. 2. Halonen PM, Paatero H, Hovorka J, Haasio J, Korttila K. Comparison of two fentanyl doses to improve epidural anaesthesia with 0.5% bupivacaine for caesarean section. Acta Anaesthesiol Scand 1993;37:774779. 3. Johnson C, Ransil BJ, Oriol N. Comparison of onset time between 0.5% bupivacaine and 3% 2-chloroprocaine with and without 75 g fentanyl. Reg Anesth 1991;16:228-231. 4. Kasaba T, Yoshikawa G, Seguchi T, Takasaki M. Epidural fentanyl improves the onset and spread of epidural mepivacaine anlagesia. Can J Anaesth 1996;43: 1211-1215. 5. Boidin MP, Sulimma H, Hamers SEES. Fentanyl in 2% mepivacaine compared with fentanyl in 0.5% bupivacaine: Two parallel controlled double blind studies. Acta Anaesthesiol Scand 1991;42:93-99. 6. DiFazio CA, Rowlingson JC. Additives to local anesthetic solution. In: Brown DL, ed. Regional Anesthesia and Analgesia. Philadelphia, PA: Saunders; 1996:232239. 7. Kaneko M, Saito Y, Kirhara Y, Collins JG, Kosaka Y. Synergistic antinociceptive interaction after epidural coadministration of morphine and lidocaine in rats. Anesthesiology 1994;80:137-150. 8. Kirota K, Appadu BL, Grandy DK, Devi LA, Lambert DG. Effect of lidocaine on cAMP formation with recombinant opioid receptors expressed in Chinese hamster ovary cells [abstr]. Anesthesiology 1998;89: A801. 9. Li YM, Wingrove DE, Too P, Margarita M, Stimson ER, Strichartz GR, Maggio JE. Local anesthetics inhibit sustance P binding and evoked increases in intracellular Ca2⫹. Anesthesiology 1995;82:166-173.
526
Regional Anesthesia and Pain Medicine Vol. 26 No. 6 November–December 2001
10. North RA, Williams JT. How do opiates inhibit neurotransmitter release? Trends Neurosci 1983;6:337-339. 11. McFadzean I. The ionic mechanisms underlying opioid actions. Neuropeptides 1988;11:173-180. 12. Famewo CE, Naguib M. Spinal analgesia with meperidine as the sole agent. Can J Anaesth 1985;32:533537. 13. Smith B, Pinnock C, Fischer B, Trotler T, Scott P. Unilateral analgesia following injection of fentanyl into the lumbosacral plexus. Lancet 1987;1:14971498. 14. Gissen AJ, Gugino LD, Datta S, Niller J, Covino BG. Effects of fentanyl and sufentanil on peripheral mammalian nerves. Anesth Analg 1987;66:12721276. 15. Power I, Hons BS, Brown DT, Wildsmith JAW. The effect of fentanyl, meperidine and diamorphine on nerve conduction in vitro. Reg Anesth 1991;16:204208. 16. Polley LS, Columb MO, Naughton NN, Wagner DS, Dorantes M, van de Ven CJM. Effect of intravenous
17.
18.
19.
20.
21.
versus epidural fentanyl on the minimum local analgesic concentration of epidural bupivacaine in labor. Anesthesiology 2000;93:122-128. Glass PS, Estok P, Ginsberg B, Goldberg JS, Sladen RN. Use of patient-controlled analgesia to compare the efficacy of epidural to intravenous fentanyl administration. Reg Anesth 1992;74:345-351. McQuay HJ. Epidural analgesics. In: Wall PD, Melzack R, eds. Texbook of Pain. 3rd ed. Edinburgh, Scotland: Churchill Livingstone, 1994:1025-1034. Morgan BM, Aulakh JM, Barker JP, Reginald PW, Goroszeniuk T, Trojanowski A. Anaesthetic morbidity following caesarean section under epidural or general anaesthesia. Lancet 1984; 1:328-330. Liu WHD, Luxton MC. The effect of prophylactic fentanyl on shivering in selective Caesarean section under epidural analgesia. Anaesthesia 1991;46:344348. Kalso E. Effects of intrathecal morphine, injected with bupivacaine, on pain after orthopaedic surgery. Br J Anaesth 1983;55:415-421.
Epidural, Fentanyl, Lidocaine, Onset.
T
he speed of onset of epidural anesthesia is slower than spinal anesthesia. The addition of fentanyl to the local anesthetic solution is widely used in epidural anesthesia.1,2 Epidural fentanyl has been shown to shorten the onset time of anesthesia when used with epidural bupivacaine and mepivacaine.3,4 Other investigators have reported no change in the onset of anesthesia with the addition of fentanyl to epidural mepivacaine.5 There are no data for fentanyl’s impact on the latency of lidocaine epidural anesthesia. The purpose of this study is to examine the effect of epidural fentanyl on the From the Department of Anesthesiology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan. Accepted for publication July 9, 2001. Reprint requests: Chen-Hwan Cherng, M.D., D.M.Sc., 7F, No. 13, Lane 61, Won-Shou Road, Mu-Cha, 116, Taipei, Taiwan. E-mail: [email protected] © 2001 by the American Society of Regional Anesthesia and Pain Medicine. 1098-7339/01/2606-0013$35.00/0 doi:10.1053/rapm.2001.27852
onset time of sensory block during epidural lidocaine anesthesia.
Methods This was a randomized, double-blind, prospective study. After approval from the human research review committee of our institute, informed consent from each patient was obtained. Thirty-six young (⬃20 to 22 years old) male patients, American Society of Anesthesiologists (ASA) physical status I, scheduled for knee arthroscopy were included. The patients were randomly allocated into 3 groups: epidural fentanyl (EF), intravenous fentanyl (IF), and control (C) groups, with 12 patients in each group. The patients were monitored with electrocardiogram, arterial blood pressure, heart rate, and pulse oximetry during surgery. With patients in the left lateral decubitus position, epidural catheters were inserted at L3-4 interspace and advanced 5 cm into the space. A test dose of 3 mL of 2% lidocaine (ASTRA, So¨derta¨lje, Sweden) containing 1:200,000
Regional Anesthesia and Pain Medicine, Vol 26, No 6 (November–December), 2001: pp 523–526
523
524
Regional Anesthesia and Pain Medicine Vol. 26 No. 6 November–December 2001
Table 1. Demographic Data of the Three Groups
Age (yr) Weight (kg) Height (cm)
EF (n ⫽ 12)
IF (n ⫽ 12)
C (n ⫽ 12)
22.1 ⫾ 3.1 69.1 ⫾ 6.4 169.8 ⫾ 3.6
21.7 ⫾ 1.8 70.9 ⫾ 4.9 171.2 ⫾ 3.2
22.2 ⫾ 1.7 68.4 ⫾ 5.8 171.0 ⫾ 5.1
NOTE. Data ⫽ mean ⫾ SD.
epinephrine (freshly added) was administered to minimize development of intrathecal or intravenous (IV) injection. Three minutes later, the patients of group EF received the epidural administration of 17 mL of 2% lidocaine (containing 1:200,000 epinephrine) plus 100 g (2 mL) of fentanyl, followed by IV injection of 2 mL of normal saline. The patients of group IF received the epidural administration of 17 mL of 2% lidocaine (containing 1:200,000 epinephrine) plus 2 mL of normal saline, followed by an IV injection of 100 g (2 mL) of fentanyl. The patients of group C received the epidural administration of 17 mL of 2% lidocaine (containing 1:200,000 epinephrine) plus 2 mL of normal saline along with an IV injection of 2 mL of normal saline. The speed of epidural lidocaine administration was consistent in all groups, with a rate of 3 mL/10 s. The sensory block was assessed by pinprick method at 2.5-minute intervals for 30 minutes. Pinprick sensation was examined using a 21-gauge needle in a cephalad to caudal fashion along the left anterior axillary line by a blinded observer. The latency of block was defined as the time from epidural injection to the occurrence of sensory block at the T10 dermatome. The upper level of sensory block was also recorded. Arterial blood pressure and heart rate were measured every 2.5 minutes after epidural injection. Hypotension (systolic blood pressure ⬍ 100 mm Hg or a decrease of more than 30% from baseline) was treated with 5 mg of IV ephedrine as needed. Side effects such as nausea, vomiting, pruritus, respiratory depression, or shivering were recorded during surgery, and difficulty in micturition was also recorded postoperatively. The pH value of the 2 lidocaine solutions used in this study were determined by a pH meter. The results were expressed as mean ⫾ SD or median (range) for the level of sensory block. The pH of the local anesthetic solutions were analyzed by Student’s t-test. The difference of onset times was analyzed using analysis of variance (ANOVA) and the Student-Newman-Keuls test for posthoc comparison. The upper levels of sensory block were compared using the Kruskal-Wallis test and the Dunn’s multiple comparison procedure for posthoc comparison. The incidences of side effects among
groups were analyzed by chi-squared test. P ⬍ .05 was considered significant.
Results The three study groups were similar in age, weight, and height (Table 1). The pH of the 2 lidocaine solutions was no different: 6.61 ⫾ 0.02 (n ⫽ 3) in the 17 ml of 2% lidocaine containing 1:200,000 epinephrine plus 100 g (2 mL) of fentanyl, and 6.63 ⫾ 0.03 (n ⫽ 3) in the 17 ml of 2% lidocaine containing 1:200,000 epinephrine plus 2 mL of normal saline. The anesthetic characteristics of the 3 groups are shown in Table 2. The onset time of sensory block up to the T10 dermatome was significantly more rapid in the EF group than in the IF and C groups. The upper level of sensory block was significantly higher in the EF group than in the IF and C groups. The incidence of shivering in the EF group (3 of 12) was lower than that in the IF (5 of 12) and C groups (8 of 12); however, the difference was not significant. The changes of arterial blood pressure and heart rate were no different among the 3 groups. Nausea, vomiting, pruritus, and respiratory depression were not observed in any patients. No patient required urinary catheterization postoperatively.
Discussion The results of the present study show that addition of 100 g fentanyl to 2% epidural lidocaine solution accelerates the onset of the sensory block. The mechanisms by which fentanyl speeds the onset of sensory block are not clear. Alkalinization of the local anesthetic solutions is known to shorten the onset time of sensory block.6 The pH values of the 2 lidocaine solutions used in this study, fentanyl–lidocaine and normal saline–lidocaine solutions, were not different. Therefore, the pH changes did not account for this finding. A synergistic interaction between lidocaine and opioids with epidural administration has been reported.7 It appears that lidocaine and opioids exert their independent action via separate and distinct mechanisms. Lidocaine blocks impulses by inhibit-
Table 2. Anesthetic Characteristics of the Three Groups EF (n ⫽ 12)
IF (n ⫽ 12)
C (n ⫽ 12)
Onset time of sensory block 8.3 ⫾ 3.7* 13.1 ⫾ 4.2 14.2 ⫾ 5.4 to T10 dermatome (min) Upper level of sensory block T6 (3-10)* T8 (6-10) T8 (5-10) NOTE. Data ⫽ mean ⫾ SD or median (range). *P ⬍ .05 v IF and C groups.
Epidural Fentanyl and Lidocaine
ing sodium channels, while opioids act on the opioid receptors to produce an inhibitory effect on intracellular second messengers. In fact, lidocaine blocks the sodium channels, and also affects synaptic transmission. Kirota et al.8 reported that lidocaine dose-dependently inhibited the cyclic adenosine monophosphate formation in Chinese hamster ovary cells. Moreover, Li et al.9 showed that lidocaine inhibited both substance P binding and substance P– evoked increases in intracellular calcium. In contrast, opioids interact with opioid receptors either pre- or postsynaptically to exert an inhibitory effect on the neuronal transmission.10 In addition, opioids can also open potassium channels, which results in membrane hyperpolarization and decreased neuronal excitability.11 Therefore, the combination of local anesthetics and opioids may effectively inhibit multiple areas of neuronal excitability. Another possible mechanism of fentanyl accelerating the onset of epidural lidocaine is the local anesthetic effect of fentanyl. Meperidine has been reported as a sole agent for spinal anesthesia.12 Furthermore, unilateral analgesia after injection of fentanyl near the lumbosacral plexus was also reported,13 and a local anesthetic action of fentanyl was proposed. In electrophysiological studies, Gissen et al.14 found that perineural fentanyl and sufentanil inhibited the action potential of A and C fibers, and naloxone pretreatment did not prevent this inhibitory effect. Similarly, Power et al.15 showed that fentanyl blocked the nerve conduction of A and C fibers, and naloxone did not prevent this inhibitory effect. These results suggested that fentanyl may have some local anesthetic action that is not mediated via the opioid receptors. Compared with the C and IF groups, the upper level of sensory block was higher in the EF group. This finding was consistent with a previous report that epidural fentanyl enhanced the spread of sensory analgesia during bupivacaine epidural analgesia.16 A synergism of opioids and local anesthetics was proposed. The primary site of action of epidural fentanyl remains controversial; both spinal11,16 and supraspinal17 sites of action were proposed. Epidural fentanyl exerts its spinal effect on the dorsal horn of the spinal cord, where it binds to opioid receptors.18 Epidural fentanyl may also exert a supraspinal action by distribution from systemic absorption and by intrathecal cephalad spread. From the results of the present study, the IF group had no effect on either the onset time or the upper level of sensory block of lidocaine epidural anesthesia. This finding suggests that, in this study, fentanyl acted primarily at a spinal level. Shivering during epidural anesthesia has been reported,19 and epidural fentanyl has been used to
•
Cherng et al.
525
reduce shivering during epidural anesthesia.20 Our results showed that the frequency of shivering in the EF group was lower than that of the C and IF groups, though this difference was not statistically significant. In our study, side effects such as nausea, vomiting, pruritus, respiratory depression, urinary retention, and hypotension were not observed. It could be caused by the moderate doses of epidural medications used or by the young age of the patients in the study. It is known that side effects of intrathecal morphine, such as nausea/vomiting or difficulty with micturition, are less frequent in younger patients than in older patients.21 In conclusion, addition of 100 g fentanyl to 2% lidocaine (containing 1:200,000 epinephrine) shortened the onset time of sensory block during epidural anesthesia without increased side effects.
References 1. King MJ, Bowden MI, Cooper GM. Epidural fentanyl and 0.5% bupivacaine for elective caesarean section. Anaesthesia 1990;45:285-288. 2. Halonen PM, Paatero H, Hovorka J, Haasio J, Korttila K. Comparison of two fentanyl doses to improve epidural anaesthesia with 0.5% bupivacaine for caesarean section. Acta Anaesthesiol Scand 1993;37:774779. 3. Johnson C, Ransil BJ, Oriol N. Comparison of onset time between 0.5% bupivacaine and 3% 2-chloroprocaine with and without 75 g fentanyl. Reg Anesth 1991;16:228-231. 4. Kasaba T, Yoshikawa G, Seguchi T, Takasaki M. Epidural fentanyl improves the onset and spread of epidural mepivacaine anlagesia. Can J Anaesth 1996;43: 1211-1215. 5. Boidin MP, Sulimma H, Hamers SEES. Fentanyl in 2% mepivacaine compared with fentanyl in 0.5% bupivacaine: Two parallel controlled double blind studies. Acta Anaesthesiol Scand 1991;42:93-99. 6. DiFazio CA, Rowlingson JC. Additives to local anesthetic solution. In: Brown DL, ed. Regional Anesthesia and Analgesia. Philadelphia, PA: Saunders; 1996:232239. 7. Kaneko M, Saito Y, Kirhara Y, Collins JG, Kosaka Y. Synergistic antinociceptive interaction after epidural coadministration of morphine and lidocaine in rats. Anesthesiology 1994;80:137-150. 8. Kirota K, Appadu BL, Grandy DK, Devi LA, Lambert DG. Effect of lidocaine on cAMP formation with recombinant opioid receptors expressed in Chinese hamster ovary cells [abstr]. Anesthesiology 1998;89: A801. 9. Li YM, Wingrove DE, Too P, Margarita M, Stimson ER, Strichartz GR, Maggio JE. Local anesthetics inhibit sustance P binding and evoked increases in intracellular Ca2⫹. Anesthesiology 1995;82:166-173.
526
Regional Anesthesia and Pain Medicine Vol. 26 No. 6 November–December 2001
10. North RA, Williams JT. How do opiates inhibit neurotransmitter release? Trends Neurosci 1983;6:337-339. 11. McFadzean I. The ionic mechanisms underlying opioid actions. Neuropeptides 1988;11:173-180. 12. Famewo CE, Naguib M. Spinal analgesia with meperidine as the sole agent. Can J Anaesth 1985;32:533537. 13. Smith B, Pinnock C, Fischer B, Trotler T, Scott P. Unilateral analgesia following injection of fentanyl into the lumbosacral plexus. Lancet 1987;1:14971498. 14. Gissen AJ, Gugino LD, Datta S, Niller J, Covino BG. Effects of fentanyl and sufentanil on peripheral mammalian nerves. Anesth Analg 1987;66:12721276. 15. Power I, Hons BS, Brown DT, Wildsmith JAW. The effect of fentanyl, meperidine and diamorphine on nerve conduction in vitro. Reg Anesth 1991;16:204208. 16. Polley LS, Columb MO, Naughton NN, Wagner DS, Dorantes M, van de Ven CJM. Effect of intravenous
17.
18.
19.
20.
21.
versus epidural fentanyl on the minimum local analgesic concentration of epidural bupivacaine in labor. Anesthesiology 2000;93:122-128. Glass PS, Estok P, Ginsberg B, Goldberg JS, Sladen RN. Use of patient-controlled analgesia to compare the efficacy of epidural to intravenous fentanyl administration. Reg Anesth 1992;74:345-351. McQuay HJ. Epidural analgesics. In: Wall PD, Melzack R, eds. Texbook of Pain. 3rd ed. Edinburgh, Scotland: Churchill Livingstone, 1994:1025-1034. Morgan BM, Aulakh JM, Barker JP, Reginald PW, Goroszeniuk T, Trojanowski A. Anaesthetic morbidity following caesarean section under epidural or general anaesthesia. Lancet 1984; 1:328-330. Liu WHD, Luxton MC. The effect of prophylactic fentanyl on shivering in selective Caesarean section under epidural analgesia. Anaesthesia 1991;46:344348. Kalso E. Effects of intrathecal morphine, injected with bupivacaine, on pain after orthopaedic surgery. Br J Anaesth 1983;55:415-421.