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ketamine sedation in calves and its reversal with atipamezole
J. vet. Anaesth. Vol. 18 (1991)
Medetomidine/ketamine sedation in calves and its reversal with atipamezole M. Raekallio, M. Kivalo", H. Jalankat and 0.VainioS College of Veterinary Medicine, Department of Clinical Sciences, Hameentie 57, SF-00580 Helsinki; *College of Veterinary Medicine, Department of Anatomy and Embryology, SF-00580 Helsinki; +HelsinkiZoo and $Orion Corporation Farmos, R & D, Pharmaceuticals, SF-20101 Turku, Finland.
SUMMARY
atipamezole to reverse the sedation induced by medetomidine-ketamine.
Atipamezole was used to reverse the sedation induced in calves by medetomidine/ ketamine. Thirteen claves subjected to umbilical surgery received medetomidine 20 p g / k g bodyweight ( b w t ) and ketamine 0.5 mg/kg bwt intravenously (iv) from a mixture of the drugs in one syringe. Atipamezole was given at doses of 20 to 60 pg/kg iv and intramuscularly (im) to the calves at the end of the operation. Following the administration of medetomidine and ketamine, PaC02 increased whereas pH, P a 0 2 and heart rate decreased. Reversing the effects of medetomidine with atipamezole did not cause undesirable effects; recovery was rapid and smooth, most of the animals reached a standing position within 1 to 3 mins after the atipamezole injection.
MATERIALS AND METHODS Medetomidine (Domitor; Orion Corporation Farmos, Turku, Finland) (1 mg/ml) and ketamine (Ketalar; Parke-Davis S. A., Barcelona, Spain) (50 mg/ml) were mixed in a syringe and the mixture used to facilitate corrective surgery in 13 calves with umbilical problems (hernia and/or abscess). All were given medetomidine 20 pg/kg bodyweight (bwt) and ketamine 0.5 mg/kg bwt by intravenous (iv) injection. Calves weighed 45 to 111 kg (mean 65 kg). Three of the calves were operated on in lateral decubitus and 10 while supine. Mepivacaine (Carbocain; Astra, Sodertalje, Swede;)( 20 mg/ml) was used as a local anaesthetic subcutaneously at the incision site in the calves that were operated on in dorsal recumbency. Local anaesthetic was not used in calves operated on in lateral decubitus because the operation was short and the calves did not react to the procedure. The clinical signs during the induction period and anaesthesia were observed. When a calf developed spontaneous limb movements during the operation, half of the initial medetomidine-ketamine dose was administered iv.
INTRODUCTION An anaesthetic technique appropriate for cattle should be easy and safe to use. It should be possible to reverse its effects when the surgical procedure is finished or in an emergency. The purpose of the present study was to investigate the suitability of medetomidine/ ketamine combination sedation for umbilical surgery in calves and to evaluate the use of
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160 r
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0
Time (mins)
I
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1 15
1
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1
1 45
Time (rnins)
Fig 1: Heart and respiratory rates (mean f sd) of calves anaestketised with a rnedetornidine-ketarninecombination in dorsal ( I ) (n=9) and lateral (-> ) (n=3)recumbency. 45
J. vet. Anaesth. Vol. 18 (1991)
-
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7.40 -
6.0
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Heart, pulse and respiratory rate were recorded before and 1.2 f 2.0 mmol/litre 5 mins after injection in before the agents were administered and at 5, 10, 15 calves operated on in dorsal recumbency. The body and every 15 mins thereafter. The body temperature of temperature of the calves decreased significantly eight calves was measured before administration of during the anaesthetic from 39.3 f 0.3"C to 38.4 f 0.5"C. The calves started to have s p o n t a n e o u s limb medetomidine-ketamine a n d at the end of the operation (at least 43 mins after the first injection). movements 32.6 +_ 6.5 mins (range, 25 to 43 mins) after Blood samples were collected anaerobically by arterial administration of medetomidine and ketamine, and puncture from the femoral artery before the first they all received an additional 'top-up' dose of the injection and 5, 10,15 and every 15 mins thereafter. The combination of half of the initial dose. Two of the arterial blood samples were stored in melting ice until calves started spontaneous leg movements at 15 and 19 analysed with an ABL 300 auto-analyser (Radiometer, mins, respectively, after the first 'top-up' injection, and Copenhagen, Denmark). The holding period did not again at 29 and 35 mins, respectively, after the second. The f u r t h e r doses of the combination provided exceed 2 h. Atipamezole was administered at the end of the adequate immobilisation. In the others, clinically operation. One calf was injected iv with 20 pg/kg bwt satisfactory operating conditions persisted after the and two calves with 30 p g / k g bwt iv. Ten calves first 'top-up' until they were injected with atipamezole. Atipamezole was given at the end of the operation, received atipamezole 60 pg/kg bwt; the entire dose was given iv to five calves Pand half intramuscularly (im), 15 to 118 mins after the first medetomidine-ketamine half iv to the other five. The animals were observed injection (7 to 30 mins after the last addition). The continuously during the recovery period until they calves attained sternal recumbency 1.9 f 2.0 mins were standing. (range, 0.6 to 8.4 mins) after atipamezole injection and The data were analysed with 'Statgraphics' stood at the first attempt 2.9 f 2.9 mins (range 0.7 to statistical graphics program using paired and unpaired 10.1 mins) after administration of atipamezole. There Student's t tests. Minimum statistical significance was was no significant difference between calves given half of the dose im or iv and those given the full dose iv in taken as P<0.05. sternal recumbency time or standing time. RESULTS DISCUSSION The calves showed the first signs of sedation, sinking of the head and reduced awareness, 0.5 k 0.16 After administration of medetomidine and ketamine mins (mean f s d ; range, 0.3 to 1 mins) after iv to the calves, PaC02 increased and heart rate, Pa02 and administration of the combination of medetomidine pH decreased, as has been reported in calves during and ketamine. They lay down, usually first to sternal xylazine/ketamine narcosis (Blaze, Holland and Grant Ten minutes after the first recumbency, 0.6 f 0.13 mins after the injection (range, 1988). 0.4 to 0.8 mins, four missing values) and were deeply medetomidine/ ketamine injection all the calves were sedated in lateral recumbency after 1.7 f 0.57 mins acidotic. The lowest individual arterial pH measured in (range, 0.9 to 3.5 mins). this study was 7.22 which, however, was not lower Heart and respiratory rates, Pa02, PaC02 and pH than the lowest p H recorded by Blaze et a1 (1988). before and after administration of medetomidine are Fifteen minutes after the first injection Pa02 and PaC02 shown in Figures 1 and 2. There was a statistically were, in this study, at the same level a s in their significant decrease in the mean heart rate, arterial pH xylazine/ ketamine treated animals. and Pa02 and an increase in PaC02 within 5 mins of The combination of medetomidine and ketamine the injection. Respiratory rate increased in calves resulted in deep sedation lasting about 32 mins. The operated on in lateral recumbency, Base excess had a duration of xylazine/ketamine (0.2 mg/kg bwt im and slight tendency to decrease, being 2.6 f 3.1 mmol/litre 5 mg/kg bwt iv or 10 mg/kg bwt im, respectively) was 46
1. vet. Anaesth. Vol. 18 (1991) -
approximately 23 mins in calves older than 10 weeks of age (Waterman 1981). In our experience, the duration of the sedation and analgesia induced by medetomidine/ ketamine is not always long enough for students to perform umbilical herniotomy. In the present study, local analgesic solution was used only in the subcutaneous tissues to reduce the need for another dose of medetomidine/ ketamine while the skin was sutured, and only for calves operated on in dorsal recumbency. The calves did not react when the muscular layers or peritoneum were manipulated. The potency of medetomidine made it possible to reduce the dose of ketamine to 0.5 mg/kg bwt, which is only 10 per cent of the dose used in combination with xylazine (Waterman 1981; Blaze et al 1988). Due to the low dose of ketamine used, reversing the effects of medetomidine with atipamezole did not cause any undesirable effects. The recovery w a s r a p i d a n d
smooth after the atipamezole injection and the calves w e r e able t o w a l k t o t h e b a r n immediately after standing up. The combination of medetomidine and ketamine produced satisfactory restraint o r anaesthesia for umbilical surgery in calves, although some hypoxaemia and respiratory acidosis occurred. Muscle relaxation was good and no complications were encountered. Atipamezole was shown to be effective in reversing sedation induced by the combination of medetomidine and ketamine used in calves. REFERENCES
Blaze, C. A., Holland, R. E. and Grant, A. L. (1988) Gas exchange during xylazine-ketamine anesthesia in neonatal calves. Vet.Suvg. 17,155-159. Waterman, A. E. (1981) Preliminary observations on the use of a combination of xylazine and ketamine hydrochloride in calves. Vet.Rec. 109,464-467.
DO ANAESTHETISED HORSES HAVE UNFAVOURABLE ODDS? WE DON'T KNOW BUT WE SHOULD. Please participate in this confidential enquiry into perioperative equine fatalities. WHY? There is a risk with any general anaesthetic whether the patient be man or beast. The annual CEPOD surveys (Confidential Enquiry into Perioperative Deaths) in human surgery have quantified these risks and highlighted the predisposing causes of all deaths after any surgical procedure. This has saved lives. HOW? It is intended to carry out an accurate audit of all equine deaths within five days of any operative procedure in the U.K. in whatever veterinary establishment. Please help by agreeing to participate. You will then be sent two forms: Part One: A simple day-to-daydiary of all equine general anaesthetics. Part Two: The more detailed questionnaire into any post operative death within five days of surgery. This survey is totally confidential. Completed forms should be sent initially to the CEPOD office in the Royal College of Surgeons, London where the equivalent human forms are also processed. All identifiable features from the forms of both the veterinary establishment and equine patient will be destroyed subsequent to their data being evaluated. WHY SHOULD YOU? This survey is an ongoing project, fully endorsed by the A.V.A., and will report annually to give lifesaving feedback to those who are involved in equine surgery. It's success depends totally on your participation. The numbers of perioperative fatalities in any one clinic may be small but the picture over the whole country may tell a different story and highlight areas that need further research. We don't know but we should.
This survey is now underway and the organiser is interested in having more participants. Ifinterested please send your name and address to: Mark Johnston, Rossdale & Partners, Beaufort Cottage Stables, High Street, Newmarket, Suffolk CB8 8JS.
47
Medetomidine/ketamine sedation in calves and its reversal with atipamezole M. Raekallio, M. Kivalo", H. Jalankat and 0.VainioS College of Veterinary Medicine, Department of Clinical Sciences, Hameentie 57, SF-00580 Helsinki; *College of Veterinary Medicine, Department of Anatomy and Embryology, SF-00580 Helsinki; +HelsinkiZoo and $Orion Corporation Farmos, R & D, Pharmaceuticals, SF-20101 Turku, Finland.
SUMMARY
atipamezole to reverse the sedation induced by medetomidine-ketamine.
Atipamezole was used to reverse the sedation induced in calves by medetomidine/ ketamine. Thirteen claves subjected to umbilical surgery received medetomidine 20 p g / k g bodyweight ( b w t ) and ketamine 0.5 mg/kg bwt intravenously (iv) from a mixture of the drugs in one syringe. Atipamezole was given at doses of 20 to 60 pg/kg iv and intramuscularly (im) to the calves at the end of the operation. Following the administration of medetomidine and ketamine, PaC02 increased whereas pH, P a 0 2 and heart rate decreased. Reversing the effects of medetomidine with atipamezole did not cause undesirable effects; recovery was rapid and smooth, most of the animals reached a standing position within 1 to 3 mins after the atipamezole injection.
MATERIALS AND METHODS Medetomidine (Domitor; Orion Corporation Farmos, Turku, Finland) (1 mg/ml) and ketamine (Ketalar; Parke-Davis S. A., Barcelona, Spain) (50 mg/ml) were mixed in a syringe and the mixture used to facilitate corrective surgery in 13 calves with umbilical problems (hernia and/or abscess). All were given medetomidine 20 pg/kg bodyweight (bwt) and ketamine 0.5 mg/kg bwt by intravenous (iv) injection. Calves weighed 45 to 111 kg (mean 65 kg). Three of the calves were operated on in lateral decubitus and 10 while supine. Mepivacaine (Carbocain; Astra, Sodertalje, Swede;)( 20 mg/ml) was used as a local anaesthetic subcutaneously at the incision site in the calves that were operated on in dorsal recumbency. Local anaesthetic was not used in calves operated on in lateral decubitus because the operation was short and the calves did not react to the procedure. The clinical signs during the induction period and anaesthesia were observed. When a calf developed spontaneous limb movements during the operation, half of the initial medetomidine-ketamine dose was administered iv.
INTRODUCTION An anaesthetic technique appropriate for cattle should be easy and safe to use. It should be possible to reverse its effects when the surgical procedure is finished or in an emergency. The purpose of the present study was to investigate the suitability of medetomidine/ ketamine combination sedation for umbilical surgery in calves and to evaluate the use of
:I
80 r
160 r
20
:
0
:
l 40
r
m
a,
I
OL
O L
I
a,
P:
1
I
I
I
I
15
I 30
1
I
I
L
45
0
Time (mins)
I
1
1 15
1
1
I 30
I
1
1 45
Time (rnins)
Fig 1: Heart and respiratory rates (mean f sd) of calves anaestketised with a rnedetornidine-ketarninecombination in dorsal ( I ) (n=9) and lateral (-> ) (n=3)recumbency. 45
J. vet. Anaesth. Vol. 18 (1991)
-
10.0
-
7.45
8.0
-
7.40 -
6.0
I
h
m
cu
7.35 -
0
0,
I
4.0
-
2.0
-
Q
7.30 7.25
-
Heart, pulse and respiratory rate were recorded before and 1.2 f 2.0 mmol/litre 5 mins after injection in before the agents were administered and at 5, 10, 15 calves operated on in dorsal recumbency. The body and every 15 mins thereafter. The body temperature of temperature of the calves decreased significantly eight calves was measured before administration of during the anaesthetic from 39.3 f 0.3"C to 38.4 f 0.5"C. The calves started to have s p o n t a n e o u s limb medetomidine-ketamine a n d at the end of the operation (at least 43 mins after the first injection). movements 32.6 +_ 6.5 mins (range, 25 to 43 mins) after Blood samples were collected anaerobically by arterial administration of medetomidine and ketamine, and puncture from the femoral artery before the first they all received an additional 'top-up' dose of the injection and 5, 10,15 and every 15 mins thereafter. The combination of half of the initial dose. Two of the arterial blood samples were stored in melting ice until calves started spontaneous leg movements at 15 and 19 analysed with an ABL 300 auto-analyser (Radiometer, mins, respectively, after the first 'top-up' injection, and Copenhagen, Denmark). The holding period did not again at 29 and 35 mins, respectively, after the second. The f u r t h e r doses of the combination provided exceed 2 h. Atipamezole was administered at the end of the adequate immobilisation. In the others, clinically operation. One calf was injected iv with 20 pg/kg bwt satisfactory operating conditions persisted after the and two calves with 30 p g / k g bwt iv. Ten calves first 'top-up' until they were injected with atipamezole. Atipamezole was given at the end of the operation, received atipamezole 60 pg/kg bwt; the entire dose was given iv to five calves Pand half intramuscularly (im), 15 to 118 mins after the first medetomidine-ketamine half iv to the other five. The animals were observed injection (7 to 30 mins after the last addition). The continuously during the recovery period until they calves attained sternal recumbency 1.9 f 2.0 mins were standing. (range, 0.6 to 8.4 mins) after atipamezole injection and The data were analysed with 'Statgraphics' stood at the first attempt 2.9 f 2.9 mins (range 0.7 to statistical graphics program using paired and unpaired 10.1 mins) after administration of atipamezole. There Student's t tests. Minimum statistical significance was was no significant difference between calves given half of the dose im or iv and those given the full dose iv in taken as P<0.05. sternal recumbency time or standing time. RESULTS DISCUSSION The calves showed the first signs of sedation, sinking of the head and reduced awareness, 0.5 k 0.16 After administration of medetomidine and ketamine mins (mean f s d ; range, 0.3 to 1 mins) after iv to the calves, PaC02 increased and heart rate, Pa02 and administration of the combination of medetomidine pH decreased, as has been reported in calves during and ketamine. They lay down, usually first to sternal xylazine/ketamine narcosis (Blaze, Holland and Grant Ten minutes after the first recumbency, 0.6 f 0.13 mins after the injection (range, 1988). 0.4 to 0.8 mins, four missing values) and were deeply medetomidine/ ketamine injection all the calves were sedated in lateral recumbency after 1.7 f 0.57 mins acidotic. The lowest individual arterial pH measured in (range, 0.9 to 3.5 mins). this study was 7.22 which, however, was not lower Heart and respiratory rates, Pa02, PaC02 and pH than the lowest p H recorded by Blaze et a1 (1988). before and after administration of medetomidine are Fifteen minutes after the first injection Pa02 and PaC02 shown in Figures 1 and 2. There was a statistically were, in this study, at the same level a s in their significant decrease in the mean heart rate, arterial pH xylazine/ ketamine treated animals. and Pa02 and an increase in PaC02 within 5 mins of The combination of medetomidine and ketamine the injection. Respiratory rate increased in calves resulted in deep sedation lasting about 32 mins. The operated on in lateral recumbency, Base excess had a duration of xylazine/ketamine (0.2 mg/kg bwt im and slight tendency to decrease, being 2.6 f 3.1 mmol/litre 5 mg/kg bwt iv or 10 mg/kg bwt im, respectively) was 46
1. vet. Anaesth. Vol. 18 (1991) -
approximately 23 mins in calves older than 10 weeks of age (Waterman 1981). In our experience, the duration of the sedation and analgesia induced by medetomidine/ ketamine is not always long enough for students to perform umbilical herniotomy. In the present study, local analgesic solution was used only in the subcutaneous tissues to reduce the need for another dose of medetomidine/ ketamine while the skin was sutured, and only for calves operated on in dorsal recumbency. The calves did not react when the muscular layers or peritoneum were manipulated. The potency of medetomidine made it possible to reduce the dose of ketamine to 0.5 mg/kg bwt, which is only 10 per cent of the dose used in combination with xylazine (Waterman 1981; Blaze et al 1988). Due to the low dose of ketamine used, reversing the effects of medetomidine with atipamezole did not cause any undesirable effects. The recovery w a s r a p i d a n d
smooth after the atipamezole injection and the calves w e r e able t o w a l k t o t h e b a r n immediately after standing up. The combination of medetomidine and ketamine produced satisfactory restraint o r anaesthesia for umbilical surgery in calves, although some hypoxaemia and respiratory acidosis occurred. Muscle relaxation was good and no complications were encountered. Atipamezole was shown to be effective in reversing sedation induced by the combination of medetomidine and ketamine used in calves. REFERENCES
Blaze, C. A., Holland, R. E. and Grant, A. L. (1988) Gas exchange during xylazine-ketamine anesthesia in neonatal calves. Vet.Suvg. 17,155-159. Waterman, A. E. (1981) Preliminary observations on the use of a combination of xylazine and ketamine hydrochloride in calves. Vet.Rec. 109,464-467.
DO ANAESTHETISED HORSES HAVE UNFAVOURABLE ODDS? WE DON'T KNOW BUT WE SHOULD. Please participate in this confidential enquiry into perioperative equine fatalities. WHY? There is a risk with any general anaesthetic whether the patient be man or beast. The annual CEPOD surveys (Confidential Enquiry into Perioperative Deaths) in human surgery have quantified these risks and highlighted the predisposing causes of all deaths after any surgical procedure. This has saved lives. HOW? It is intended to carry out an accurate audit of all equine deaths within five days of any operative procedure in the U.K. in whatever veterinary establishment. Please help by agreeing to participate. You will then be sent two forms: Part One: A simple day-to-daydiary of all equine general anaesthetics. Part Two: The more detailed questionnaire into any post operative death within five days of surgery. This survey is totally confidential. Completed forms should be sent initially to the CEPOD office in the Royal College of Surgeons, London where the equivalent human forms are also processed. All identifiable features from the forms of both the veterinary establishment and equine patient will be destroyed subsequent to their data being evaluated. WHY SHOULD YOU? This survey is an ongoing project, fully endorsed by the A.V.A., and will report annually to give lifesaving feedback to those who are involved in equine surgery. It's success depends totally on your participation. The numbers of perioperative fatalities in any one clinic may be small but the picture over the whole country may tell a different story and highlight areas that need further research. We don't know but we should.
This survey is now underway and the organiser is interested in having more participants. Ifinterested please send your name and address to: Mark Johnston, Rossdale & Partners, Beaufort Cottage Stables, High Street, Newmarket, Suffolk CB8 8JS.
47