- Email: [email protected]
Effect of Epidural Fat on Xylazine-induced Dorsolumbar Epidural Analgesia in Cattle
The Veterinary Journal 2003, 165, 330–332 doi:10.1016/S1090-0233(02)00247-2
Short Communication Effect of Epidural Fat on Xylazine-induced Dorsolumbar Epidural Analgesia in Cattle I. LEE, N. YAMAGISHI, K. OBOSHI and H. YAMADA Department of Clinical Veterinary Science, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido 080-8555, Japan
KEYWORDS: Dorsolumbar; epidural; fat; xylazine; cattle.
There are a number of factors that influence the spread of an anaesthetic solution in the epidural space and the duration of anaesthesia (Bromage, 1967; Skarda, 1996; Lee et al., 2001). In particular, intrinsic anatomic factors, such as the characteristics of epidural fat and veins, may affect the epidural spread of injected solution and consequently, epidural analgesia in cattle (Lee et al., 2001). Xylazine, which is an a2 -adrenergic receptor agonist, has been used in segmental dorsolumbar and caudal epidural anaesthesia in cattle (Skarda, 1996; Taguchi et al., 1998). The purpose of the present study was to investigate the effects of epidural fat and veins on sedative and analgesic effects of xylazine injected into the first interlumbar epidural space using a dorsal approach in standing cattle. Four two- to seven-year-old Holstein cattle (two cows and two steers), weighing 440 154 kg (mean SD), were used in this study. Following skin preparation and local anaesthesia, a 16-gauge, 120 mm Tuohy needle was inserted into the epidural space as previously reported (Lee et al., 2001). In experiment 1, all cattle received 5 mL of a solution containing 0.05 mg kg 1 xylazine in 0.9% saline. The solution was administered between the periosteum and epidural fat after entering the epidural space, at a rate of 0.5 mL s 1 with the needle bevel directed craCorrespondence to: I. Lee Department of Clinical Veterinary Science, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido 080-8555, Japan. Tel.: +81155-49-5379; Fax: +81-155-49-5379; E-mail: [email protected]
nially. At least two weeks later, experiment 2 was performed. After identification of the entrance to the epidural space, the epidural needle was slowly inserted 7–10 mm deeper to penetrate the epidural fat and the same dose of xylazine was injected between the epidural fat and spinal cord covered with dura mater, at the same rate as in experiment 1. Sedation, flank analgesia and ataxia were assessed as described by Taguchi et al. (1998). Descriptive statistics (mean SD) were used and a paired t test utilized to compare the time of onset and duration of sedation and analgesia (mean of left and right) of two experiments. A value of p < 0:05 was considered significant. The distance from the skin to the epidural space was 73 10 mm and the injection depth in the second experiment was 81 11 mm. Although the onset times of sedation of experiment 1 and 2 were similar, the duration of sedation in experiment 1 was significantly shorter than in experiment 2 (p < 0:01) (Table I). The degree of sedation in experiment 2 was greater than in experiment 1, but the increase was not statistically significant. The onset of analgesia of the flank in experiment 2 was significantly more rapid than in experiment 1, and the duration of analgesia was also significantly longer (p < 0:05) (Table I). There were differences between left and right flank analgesia in experiment 1, but not in experiment 2. All cattle in experiment 2 showed ataxia (onset 11:3 6:3, duration 222:5 127:4 min), but only two cattle in experiment 1 (mean of two cattle, onset 17.5, duration
1090-0233/03/$ - see front matter Ó 2003 Elsevier Science Ltd. All rights reserved.
EFFECT OF EPIDURAL FAT ON EPIDURAL ANALGESIA
331
Table I Sedation, analgesia of flank and number of spinal segments in analgesic area after epidural administration of xylazine Experiment
Sedation (min) Onset
1 2
7:5 2:9 6:3 2:5
Duration 110:0 30:3 215:0 38:1a
Analgesia of flank (min) Onset 15:6 3:1 7:5 2:9b
No. of SS
Duration 221:9 68:5 337:5 20:2b
3:4 0:3 8:8 1:9b
Mean SD; a p < 0:01; b p < 0:05; and no. of SS, number of spinal segments in analgesic area.
25.0 min). The mean number of spinal segments involved in the analgesic area of the left and right side in experiment 2 was significantly greater than in experiment 1 (p < 0:05) (Table I). The mean distance from the skin to the epidural space was 73 10 mm, which was relatively shallower than previously reported (8–12 cm) (Skarda, 1996). This difference could be related to the method of needle insertion (midline and contralateral approach). The injection depth of the second experiment was about 8 mm deeper than the entrance depth. The general pattern of epidural fat distribution of the cow resembles that of the cat (Lee et al., 2001). We confirmed that the thickness of the dorsal epidural fat was about 5–7 mm in the intervertebral portion and about 1–2 mm in the middle portion of the second lumbar vertebra by preliminary study. Because the Tuohy needle tip with a Huber point is relatively dull compared with a spinal needle, and the dura mater indents 2–6 mm during needle penetration and is relatively resistant to puncture (Zarzur & Goncalves, 1992), the needle was inserted 7–10 mm to penetrate the epidural fat after identifying the entrance to the epidural space. This method enabling us to selectively administer a solution above and/or below the epidural fat had been previously confirmed using 0.12% new methylene blue (NMB) solution. Sedation after dorsolumbar epidural administration of xylazine is common (Taguchi et al., 1998). This is due to the systemic effect of absorption as a solution injected into the dorsolumbar epidural space distributes along the longitudinal epidural veins providing ideal conditions for rapid vascular absorption (Lee et al., 2001). Although there was no difference in the time of onset, the duration of sedation was significantly longer and the degree of sedation was greater in experiment 2. It was considered that the amount of xylazine absorbed through the epidural veins was greater in experiment 2 than in experiment 1.
The onset of analgesia in the flanks was more rapid, and the duration was longer in experiment 2 than in experiment 1. There was no difference between left and right flank analgesia in experiment 2. It was considered that deeper administration of xylazine under the epidural fat induced rapid onset and longer duration of analgesia without variation of left and right sides. There could be many reasons for this phenomenon. First of all, injected solution into the epidural space by deeper administration may distribute between the epidural fat and dura mater. The solution may more easily make contact with the nerve roots or diffuse through the dura mater without interference of the epidural fat. If a solution was injected between the periosteum and epidural fat, xylazine must diffuse through the epidural fat to the nerves for the onset of analgesia. This could be one reason for rapid onset. Xylazine has relatively high lipophilicity than local anaesthetics, such as lidocaine, and may diffuse to the epidural fat during distribution and then rediffuse to the dura mater and epidural veins to maintain a balance of local concentration of xylazine in the epidural space. This might functionally lead to an increased ‘‘depot-like’’ activity of epidural fat (Meert et al., 1989; Tucker & Mather, 1998) and could be a reason for the longer duration of analgesia. Consequently, administration of xylazine between the epidural fat and dura mater could lead to rapid onset and longer duration of analgesia over a wide area than administration between the periosteum and epidural fat. We conclude that in the present study the epidural fat and veins influenced the spread and the pharmacokinetics of xylazine solution injected into the dorsolumbar epidural space in cattle. The faster onset and longer duration of analgesia with wide area could be obtained by deeper administration under the epidural fat. We believe this technique could be used clinically for flank laparotomy in the standing position in cattle.
332
THE VETERINARY JOURNAL, 165, 3
REFERENCES BROMAGE, P. R. (1967). Physiology and pharmacology of epidural analgesia. Anesthesiology 28, 592–622. LEE, I., SOEHARTONO, R. H., YAMAGISHI, N., TAGUCHI, K. & YAMADA, H. (2001). Distribution of new methylene blue injected into the dorsolumbar epidural space in cows. Veterinary Anaesthesia and Analgesia 28, 140–5. MEERT, T. F., NOORDUIN, H., VAN CRAENENDONCK, H., VERMOTE, P., BOERSMA, P. F. & JANSSEN, P. A. J. (1989). Effects of adrenaline, an a2 -adrenoceptor agonist, the volume of injection, and the global pain state of the animal on the activity of epidural sufentanil. Acta Anaesthesiologica Belgica 40, 247–61. SKARDA, R. T. (1996). Local and regional anesthetic techniques: Ruminants and swine. In: Lumb & JonesÕ Veterinary Anesthesia, eds. J. C. Thurmon, W. J. Tran-
quilli, & G. J. Benson, 3rd edn., pp. 479–514. Baltimore: Williams & Wilkins. TAGUCHI, K., YAMAGISHI, N. & YAMADA, H. (1998). Xylazineinduced thoracolumbar epidural analgesia in cows: Effects of diluent volume of xylazine and a combination of xylazine and lidocaine. Proceedings of the XXth World Buiatrics Congress, Sydney (Vol. 2) pp. 841–4. TUCKER, G. T. & MATHER, L. E. (1998). Properties, Absorption, and disposition of local anesthetic agents. In: Neural Blockage in Clinical Anesthesia and Management of Pain, eds. M. J. Cousins, & P. O. Bridenbaugh, 3rd edn., pp. 55–96. Philadelphia, USA: Lippincott-Raven. ZARZUR, E. & GONCALVES, J. J. (1992). The resistance of the human dura mater to needle penetration. Regional Anesthesia 17, 216–8. (Accepted for publication 21 August 2002)
Short Communication Effect of Epidural Fat on Xylazine-induced Dorsolumbar Epidural Analgesia in Cattle I. LEE, N. YAMAGISHI, K. OBOSHI and H. YAMADA Department of Clinical Veterinary Science, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido 080-8555, Japan
KEYWORDS: Dorsolumbar; epidural; fat; xylazine; cattle.
There are a number of factors that influence the spread of an anaesthetic solution in the epidural space and the duration of anaesthesia (Bromage, 1967; Skarda, 1996; Lee et al., 2001). In particular, intrinsic anatomic factors, such as the characteristics of epidural fat and veins, may affect the epidural spread of injected solution and consequently, epidural analgesia in cattle (Lee et al., 2001). Xylazine, which is an a2 -adrenergic receptor agonist, has been used in segmental dorsolumbar and caudal epidural anaesthesia in cattle (Skarda, 1996; Taguchi et al., 1998). The purpose of the present study was to investigate the effects of epidural fat and veins on sedative and analgesic effects of xylazine injected into the first interlumbar epidural space using a dorsal approach in standing cattle. Four two- to seven-year-old Holstein cattle (two cows and two steers), weighing 440 154 kg (mean SD), were used in this study. Following skin preparation and local anaesthesia, a 16-gauge, 120 mm Tuohy needle was inserted into the epidural space as previously reported (Lee et al., 2001). In experiment 1, all cattle received 5 mL of a solution containing 0.05 mg kg 1 xylazine in 0.9% saline. The solution was administered between the periosteum and epidural fat after entering the epidural space, at a rate of 0.5 mL s 1 with the needle bevel directed craCorrespondence to: I. Lee Department of Clinical Veterinary Science, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido 080-8555, Japan. Tel.: +81155-49-5379; Fax: +81-155-49-5379; E-mail: [email protected]
nially. At least two weeks later, experiment 2 was performed. After identification of the entrance to the epidural space, the epidural needle was slowly inserted 7–10 mm deeper to penetrate the epidural fat and the same dose of xylazine was injected between the epidural fat and spinal cord covered with dura mater, at the same rate as in experiment 1. Sedation, flank analgesia and ataxia were assessed as described by Taguchi et al. (1998). Descriptive statistics (mean SD) were used and a paired t test utilized to compare the time of onset and duration of sedation and analgesia (mean of left and right) of two experiments. A value of p < 0:05 was considered significant. The distance from the skin to the epidural space was 73 10 mm and the injection depth in the second experiment was 81 11 mm. Although the onset times of sedation of experiment 1 and 2 were similar, the duration of sedation in experiment 1 was significantly shorter than in experiment 2 (p < 0:01) (Table I). The degree of sedation in experiment 2 was greater than in experiment 1, but the increase was not statistically significant. The onset of analgesia of the flank in experiment 2 was significantly more rapid than in experiment 1, and the duration of analgesia was also significantly longer (p < 0:05) (Table I). There were differences between left and right flank analgesia in experiment 1, but not in experiment 2. All cattle in experiment 2 showed ataxia (onset 11:3 6:3, duration 222:5 127:4 min), but only two cattle in experiment 1 (mean of two cattle, onset 17.5, duration
1090-0233/03/$ - see front matter Ó 2003 Elsevier Science Ltd. All rights reserved.
EFFECT OF EPIDURAL FAT ON EPIDURAL ANALGESIA
331
Table I Sedation, analgesia of flank and number of spinal segments in analgesic area after epidural administration of xylazine Experiment
Sedation (min) Onset
1 2
7:5 2:9 6:3 2:5
Duration 110:0 30:3 215:0 38:1a
Analgesia of flank (min) Onset 15:6 3:1 7:5 2:9b
No. of SS
Duration 221:9 68:5 337:5 20:2b
3:4 0:3 8:8 1:9b
Mean SD; a p < 0:01; b p < 0:05; and no. of SS, number of spinal segments in analgesic area.
25.0 min). The mean number of spinal segments involved in the analgesic area of the left and right side in experiment 2 was significantly greater than in experiment 1 (p < 0:05) (Table I). The mean distance from the skin to the epidural space was 73 10 mm, which was relatively shallower than previously reported (8–12 cm) (Skarda, 1996). This difference could be related to the method of needle insertion (midline and contralateral approach). The injection depth of the second experiment was about 8 mm deeper than the entrance depth. The general pattern of epidural fat distribution of the cow resembles that of the cat (Lee et al., 2001). We confirmed that the thickness of the dorsal epidural fat was about 5–7 mm in the intervertebral portion and about 1–2 mm in the middle portion of the second lumbar vertebra by preliminary study. Because the Tuohy needle tip with a Huber point is relatively dull compared with a spinal needle, and the dura mater indents 2–6 mm during needle penetration and is relatively resistant to puncture (Zarzur & Goncalves, 1992), the needle was inserted 7–10 mm to penetrate the epidural fat after identifying the entrance to the epidural space. This method enabling us to selectively administer a solution above and/or below the epidural fat had been previously confirmed using 0.12% new methylene blue (NMB) solution. Sedation after dorsolumbar epidural administration of xylazine is common (Taguchi et al., 1998). This is due to the systemic effect of absorption as a solution injected into the dorsolumbar epidural space distributes along the longitudinal epidural veins providing ideal conditions for rapid vascular absorption (Lee et al., 2001). Although there was no difference in the time of onset, the duration of sedation was significantly longer and the degree of sedation was greater in experiment 2. It was considered that the amount of xylazine absorbed through the epidural veins was greater in experiment 2 than in experiment 1.
The onset of analgesia in the flanks was more rapid, and the duration was longer in experiment 2 than in experiment 1. There was no difference between left and right flank analgesia in experiment 2. It was considered that deeper administration of xylazine under the epidural fat induced rapid onset and longer duration of analgesia without variation of left and right sides. There could be many reasons for this phenomenon. First of all, injected solution into the epidural space by deeper administration may distribute between the epidural fat and dura mater. The solution may more easily make contact with the nerve roots or diffuse through the dura mater without interference of the epidural fat. If a solution was injected between the periosteum and epidural fat, xylazine must diffuse through the epidural fat to the nerves for the onset of analgesia. This could be one reason for rapid onset. Xylazine has relatively high lipophilicity than local anaesthetics, such as lidocaine, and may diffuse to the epidural fat during distribution and then rediffuse to the dura mater and epidural veins to maintain a balance of local concentration of xylazine in the epidural space. This might functionally lead to an increased ‘‘depot-like’’ activity of epidural fat (Meert et al., 1989; Tucker & Mather, 1998) and could be a reason for the longer duration of analgesia. Consequently, administration of xylazine between the epidural fat and dura mater could lead to rapid onset and longer duration of analgesia over a wide area than administration between the periosteum and epidural fat. We conclude that in the present study the epidural fat and veins influenced the spread and the pharmacokinetics of xylazine solution injected into the dorsolumbar epidural space in cattle. The faster onset and longer duration of analgesia with wide area could be obtained by deeper administration under the epidural fat. We believe this technique could be used clinically for flank laparotomy in the standing position in cattle.
332
THE VETERINARY JOURNAL, 165, 3
REFERENCES BROMAGE, P. R. (1967). Physiology and pharmacology of epidural analgesia. Anesthesiology 28, 592–622. LEE, I., SOEHARTONO, R. H., YAMAGISHI, N., TAGUCHI, K. & YAMADA, H. (2001). Distribution of new methylene blue injected into the dorsolumbar epidural space in cows. Veterinary Anaesthesia and Analgesia 28, 140–5. MEERT, T. F., NOORDUIN, H., VAN CRAENENDONCK, H., VERMOTE, P., BOERSMA, P. F. & JANSSEN, P. A. J. (1989). Effects of adrenaline, an a2 -adrenoceptor agonist, the volume of injection, and the global pain state of the animal on the activity of epidural sufentanil. Acta Anaesthesiologica Belgica 40, 247–61. SKARDA, R. T. (1996). Local and regional anesthetic techniques: Ruminants and swine. In: Lumb & JonesÕ Veterinary Anesthesia, eds. J. C. Thurmon, W. J. Tran-
quilli, & G. J. Benson, 3rd edn., pp. 479–514. Baltimore: Williams & Wilkins. TAGUCHI, K., YAMAGISHI, N. & YAMADA, H. (1998). Xylazineinduced thoracolumbar epidural analgesia in cows: Effects of diluent volume of xylazine and a combination of xylazine and lidocaine. Proceedings of the XXth World Buiatrics Congress, Sydney (Vol. 2) pp. 841–4. TUCKER, G. T. & MATHER, L. E. (1998). Properties, Absorption, and disposition of local anesthetic agents. In: Neural Blockage in Clinical Anesthesia and Management of Pain, eds. M. J. Cousins, & P. O. Bridenbaugh, 3rd edn., pp. 55–96. Philadelphia, USA: Lippincott-Raven. ZARZUR, E. & GONCALVES, J. J. (1992). The resistance of the human dura mater to needle penetration. Regional Anesthesia 17, 216–8. (Accepted for publication 21 August 2002)