Zbl. Vet. Med. A, 32, 54-58 (1985) 0 1985 Verlag Paul Parey, Berlin und Hamburg ISSN 0721-0981 / Intercode: ZVRAAX

Department of Surge y and Radiology, College of Veterinary Sciences, H a y a n a Agricultural University, Hissar-125 004, India

Evaluation of Xylazine-Ketamine Anaesthesia in Buffaloes (Bubalus bubalis)

By A. P. SINGH, JIT SINGH, P. K. PESHIN, J. S. GAHLAWAT, PREM SINGH and J. M. NIGAM

Address of authors: Department of Surgery and Radiology, College of Veterinary Sciences, Haryana Agricultural University, Hissar-125004, India

With one figure and one table

(Received for publication March 27, 1984)

Introduction Intravenous administration of ketamine hydrochloride (2 mg/kg) in buffaloes pro-

duces analgesia of very short duration (approx. 5 minutes) with muscular rigidity (6) and so it cannot be used alone in this species for surgical procedures. Xylazine is noted for its analgesic and muscular relaxation properties and has been used successfully in combination with ketamine in other domestic animals (4, 11, 16). However, such a combination for anaesthesia in buffaloes has not been evaluated. The present study was undertaken with this objective.

Material and Methods Sixteen clinically healthy male buffalo calves (Bubalus bubalis) weighing 65-1 15 kg were used.

Eight animals were used for anaesthetic properties and biochemical changes and eight were used for haemodynamic and blood gas studies. After overnight fasting, animals were given xylazine intramus- cularly (0.22 mg/kg) followed 15 minutes later by ketamine hydrochloride intravenously (2 mg/kg).

For anaesthetic studies, observations were made on the duration of anaesthesia, degree of analgesia (by pinprick method), relaxation of abdominal muscles, duration of lateral recumbency and time taken to stand on their own. For measurement of blood biochemical constituents, heparinized venous samples were collected before administration of any drug (0 hour), 15 minutes after xylazine, 30 minutes after ketamine, at the time of complete recovery and 24 hours after complete recovery. Blood constituents determined included blood urea nitrogen (14), creatinine (3) and plasma concentra- tions of total proteins (biuret method), sodium and potassium (flame photometer), chloride (chloridemeter), calcium (17) and inorganic phosphorus (2).

For haemodynamic and blood gas studies, animals were comfortably controlled in lateral recumbency. The carotid artery and jugular vein were exteriorized under local infiltration analgesia and catheters were placed in position for measurements of cardiovascular dynamics. Standard methods were used (12). A multichannel recorder was used to record the electrocardiogram (ECG), elec- troencephalogram (EEG) and blood pressure. The central venous pressure was recorded with a water manometer. The pH, p C 0 , and pOz of arterial blood were measured with a blood gas analyzer (Radiometer-Copenhagen) at 37°C. The bicarbonate (HCO;) was derived from Siggaard-Andersen alignment nomograms using measured p H and pC0,. The haemodynamic and blood gas studies were done before administration of any drug, 15 minutes after xylazine administration and at 2, 5, 10, 15, 30, 45, 60 and 75 minutes after ketamine administration.

Statistical analysis of data was done with student’s ‘t’ test at 5 YO level of significance.

U. S. Copyright Clearance Center Code Statement: 07214981/85/3201-0054$02.50/0

Evaluation of Xylazine-Ketamine Anaesthesia in Buffaloes 55

Parameter with units

Heart ratelmin

Results Following anaesthesia, there was complete relaxation of the abdominal muscles for

45-60 minutes and the tail and anal sphinctor remained relaxed for 30-50 minutes. The swallowing reflex was abolished and remained so up to 30-45 minutes after ketamine administration as was the response to deep pinpricks. Animals remained in lateral recumbency for 58.8 f 6.8 minutes. They stood up unassisted but with slight incoordina- tion by 77.9 f 7.1 minutes. Complete recovery occurred by 97.2 f 7.5 minutes when the ,animals were able to walk back to their pens.

Immediately after ketamine administration there was a decrease in time and voltage function in the EEG but after 5 to 10 minutes the high voltage complex was seen which remained for 30-45 minutes. There was no significant change in rectal temperature. The decrease in respiratory rate was maximal at 75 minutes (11.1 f 2.5) after ketamine administration, compared with the zero hour value of 21.4 k 2.9. The changes in heart rate, blood pressure and central venous pressure are shown in Table 1. Xylazine caused bradycardia, hypotension and an increase in central venous pressure. The administration of

Time in minutes I 0 X15 K 5 K10 K15 K30 K45 K60 K75

70.6 52.7 70.7 59.4 62.3 58.0 62.5 52.7 54.4 28.35 $5.21 26.79 25.60 t8.79 26.2 t9.30 r5.04 r7.2

30 &5 M) 7s

TIME IN MINUTES I V L A Z t W E DASE V lLUE

Fig. 1. The effect of xylazine-ketamine anaesthesia on acid-base status of buffalo calves

M. A. P. I torr

C V P (cm H,O)

Table 1 The effects of xylazine-ketamine anaesthesia in buffaloes. Mean values with S. E.

108.3 72.5 91.1 85.8 84.5 79.50 80.5 83.9 89.1 '14.0 t9.69 t11.58 t15.85 28.25 t8.84 '-8.20 29.80 t6.30

9.2 14.8 12.2 17.6 16.9 17.4 20.4 18.8 18.9 23.35 24.98 23.91 24.12 23.84 22.77 22.73 22.78 23.42

X = minutes after xylazine administration K = minutes after ketamine administration

56 SINGH, JIT SINGH, PESHIN, GAHLAWAT, PREM SINGH and NIGAM

ketamine moderated the degree of bradycardia and hypotension. However, the changes in cardiovascular parameters following xylazine-ketamine anaesthesia were not statistically significant (p > 0.05) due to large individual variations. The ECG did not show any consistent conduction abnormality after xylazine administration except for transient third degree A-V block in one animal. The ECG changes following ketamine administration included transient A-V dissociation and/or occasional ectopic pacing. Primary T-wave changes were seen in three animals.

The changes in acid-base status are shown in Fig. 1. The fall in arterial p H and hypercarbia were significant (P < 0.05) at 5 and 10 minutes after ketamine administration. The changes in HCO; were non-significant. A mild degree of hypoxaemia was evident but was not statistically significant. There were no significant variations in blood urea nitrogen or in plasma concentration of creatinine, total proteins, calcium, inorganic phosphorus, sodium, potassium and chloride.

Discussion Xylazine when given alone to buffaloes produces moderate muscular relaxation and

recovery from anaesthesia is delayed (8, 9). The disadvantages of ketamine in buffaloes include muscular rigidity with hypertonicity and analgesia of only very short duration (6 ) . The xylazine-ketamine combination in the present study produced satisfactory anaesthesia for 3-5 minutes, with good muscular relaxation and the recovery time was much less than with xylazine alone.

Xylazine in buffaloes causes hypotension and bradycardia; these effects can be moderated by premedication with atropine (9). In contrast, ketamine causes increases in heart rate, arterial pressure and cardiac output (6). The exact mechanism of cardiovascular stimulation by ketamine is not known but explanations include desensitization of arterial baroreceptors (I, 16) and vagal block (13). In the present study the cardiovascular inhibitory actions of xylazine were considerably moderated by ketamine hydrochloride. The ECG changes subsequent to administration of ketamine suggest dominance of the sympathetic system on the heart but the influence of possibly released catecholamines cannot be excluded.

Blood gas analysis shows the development of mild respiratory acidosis, along with mild hypoxaemia. These observations show mild hypoventilation following xylazine- ketamine anaesthesia in buffaloes. Significant respiratory depression leading to hypoventi- lation has been reported with xylazine-ketamine anaesthesia in other species (4, 5, 11, 15). In the present study xylazine-ketamine anaesthesia did not alter blood urea nitrogen or plasma concentrations of creatinine, total proteins and electrolytes. This is in contrast to the changes seen in various electrolytes when these agents were used alone in buffaloes (7, 10). Our findings show that xylazine-ketamine anaesthesia can be safely used in buffaloes for short surgical procedures without any major untoward effect.

Summary The effects of a combination of xylazine HC1 and ketamine HC1 were evaluated in

sixteen buffalo calves (Bubalus bubalis) weighing 65-1 15 kg. Animals were given xylazine intramuscularly (0.22 mg/kg), followed 15 minutes later by ketamine intravenously (2 mg/ kg). This combination produced satisfactory anaesthesia of 3O-45 minutes duration with good muscular relaxation. The changes in cardiovascular dynamics were not significant. The cardioinhibitory actions of xylazine were moderated by ketamine. There was mild respiratory acidosis and hypoxaemia. The blood urea nitrogen and the plasma concentra- tions of creatinine, total proteins and electrolytes did not alter.

Acknowledgements We thank Mr. BHIM SINGH and Mr. SHANKAR DAS for help in the laboratory and Dr.

I. S. CHANDNA for providing necessary research facilities.

Evaluation of Xylazine-Ketamine Anaesthesia in Buffaloes 57

Zusammenfassung Uberprufung der Xylazin-Ketamin-Anasthesie bei Buffelkalbern

Bei 16 Buffelkalbern (Bubalus bubalis) mit einem Gewicht von 65 bis 115 kg wurde die Wirkung einer Kombination von Xylazin-HC1 und Ketamin-HC1 untersucht. Die Tiere erhielten Xylazin (0,22 mg/kg KGW) intramuskular und 15 min spater Ketamin (2 mg/kg KGW) intravenos verabreicht. Diese Kombination bewirkte eine zufriedenstel- lende Anasthesie von 30 bis 45 rnin Dauer mit einer guten Muskelrelaxation. Die Veranderungen der kardiovaskularen Dynamik waren nicht signifikant. Die herzdamp- fende Wirkung des Xylazins wurde durch Ketamin abgeschwacht. Es konnten eine leichte respiratorische Azidose und eine Hypoxamie beobachtet werden. Blutharnstoffstickstoff und Plasmakonzentrationen von Kreatinin, Gesamtprotein und Elektrolyten anderten sich nicht.

Risumi Evaluation d’une anesthisie ii la xylazine-kitamine chez des veaux de buffle O n a examint l’effet d’une combinaison de xylazine-HC1 et de kttamine-HCL chez

16 veaux de buffle (Bubalus bubalis) d’un poids de 65 h 115 kg. Les animaux ont requ de la xylazine (0,22 mg/kg de poids) par voie intramusculaire et de la kttamine, 15 min plus tard, par voie intraveineuse (2mg/kg de poids). Cette combinaison a donne une anesthtsie satisfaisante d’une durte de 30 i 45 min avec une bonne relaxation musculaire. Les changements de la dynamique cardiovasculaire ne furent pas significatifs. L’effet d’affai- blissement cardiaque de la xylazine fut attCnui par la kttamine. O n a pu observer une ltgkre acidose respiratoire et une hypoxhie. L’azote de l’urte sanguine et les concentra- tions plasmiques de la crtatinine, des prottines totales et des tlectrolytes n’ont pas k t t modifites.

Resumen La evaluaci6n de la anestesia con xilazina-quetamina en bufalos

Se estudi6 en 16 terneros de bifala (Bubalus bubalis), con un peso desde 65 hasta 115 kg, la acci6n de una combinacidn de C1H de xilazina y C1H de quetamina. A 10s animales se administr6 la xilazina (0,22 mg/kg peso corporal) por via intramuscular y 15 min mis tarde la quetamina (2 mg/kg peso corporal) por via endovenosa. Esta combinacidn caus6 una anestesia satisfactoria de 30 hasta 45 min de duraci6n con una relajacidn muscular buena. No eran significantes las modificaciones en la dinimica cardiovascular. La acci6n cardioinhibidora de la xilazina fue moderada por la quetamina. Se pudieron observar una acidosis respiratoria ligera e hipoxemia. No se alteraron ni el nitr6geno de la urea sanguinea, ni las concentraciones plasmiticas de creatinina, proteinas totales y electr6litos.

References 1. DOWDY, E. G., and K. KAYA, 1968: Studies on the mechanism of cardiovascular response to CI-

581. Anaesthesiology 29, 931. 2. FISKE, C. M., and Y. SUBBAROW, 1925: J. Biol. Chem. 66,375. (Cited by Oser, B. L. in Hawk‘s

Physiological Chemistry. 14th Edn. Tata McGraw-Hill Book Co. 1965. pp. 1112-1116, New Delhi.)

3. FOLIN, O., and H. Wu, 1919: J. Biol. Chem. 38, 81. (Cited by OSER, B.L. In Hawk‘s Physiological Chemistry. 14th Edn. Tata McGraw-Hill Book Co. 1965, pp. 104C-1043, New Delhi.)

4. KUMAR, A., J. C. THURMAN, and H. J. HARDENBROOK, 1976: Clinical studies on ketamine HCl and xylalzine HCl in domestic goats. Vet. Med. Sm. Anim. Clin. 71, 1707-1711.

5. MUIR, W. W., R. T. SKARDA, and D. W. MILNE, 1977: Evaluation of xylazine and ketamine hydrochloride for anaesthesia in horses. Am. J. Vet. Res. 38, 195-201.

58 SINGH, JIT SINGH, PESHIN, GAHLAWAT, PREM SINGH and NIGAM

6. PATHAK, S. C., J. M. NIGAM, P. K. PESHIN, and A. P. SINGH, 1982: Anaesthetic and haemodyna- mic effects of ketamine hydrochloride in buffalo calves (Bubalus bubafzs). Am. J. Vet. Res. 43,

7. PATHAK, S. C., J. M. NIGAM, P. K. PESHIN, and A. P. SINGH, 1982: Ketamine anaesthesia in buffalo calves: haematological and biochemical studies. Indian J. Anim. Sci. 52, 319-324.

8. PESHIN, P. K., A. KUMAR, and H. SINGH, 1978: Xylazine in buffaloes I. Cardiovascular, respira- tory and sedative effect. Pantnagar, J. Res. 3, 245-249.

9. PESHIN, P. K., and A. KUMAR, 1979: Physiologic and sedative effects of xylazine in buffaloes. Indian Vet. J. 57, 864-871.

10. PESHIN, P. K., and A. KUMAR, 1983: Haemocytological and biochemical effects of xylazine in buffaloes. Indian Vet. J. 60, 981-986.

11. RINGS, D. M., and W. W. MUIR, 1982: Cardiopulmonary effects of xylazine-ketamine in calves. Can. J. Comp. Med. 46, 386-389.

12. SINGH, JIT, P. K. PESHIN, A. P. SINGH, and J. M. NIGAM, 1983: Haemodynamics, acid-base and blood gas alterations after xylazine administration in calves. Indian J. Vet. Surg. 4, 10-15.

13. TRABER, D. L., and R. D. WILSON, 1969: Involvement of sympathetic nervous system in the pressor response to ketamine. Anaesth. Analg. (Cleve) 48, 248-252.

14. VARLEY, H., 1967: Practical Clinical Biochemistry. 4th edn. p. 158. W. Heinmann, London. 15. WATERMAN, A. E., 1983: Effect of combination of ketamine and xylazine on respiratory gas

16. WATERMAN, A., and A. LEVINGSTON, 1978: Some physiological effects of ketamine in sheep. Res.

17. WEBSTER, W. W., Jr., 1962: Am. J. Clin. Path. 37, 330 (Cited in Clinical Chemistry Manual,

3 75-383.

tensions and acidbase status in calves. Vet. Rec. 113, 517.

Vet. Sci. 25, 225-233.

Spectronic-20, Bausch and Lomb, Rochester, New York).