DOI: 10.7589/2013-03-049
Journal of Wildlife Diseases, 49(4), 2013, pp. 1037–1041 # Wildlife Disease Association 2013
Physiologic Evaluation of Medetomidine-Ketamine Anesthesia in Free-ranging Svalbard (Rangifer tarandus platyrhynchus) and Wild Norwegian Reindeer (Rangifer tarandus tarandus) Alina L. Evans,1,2,8 Marianne Lian,2 Carlos G. das Neves,1 Øystein Os,3 Roy Andersen,4 Ronny Aanes,5,6 Olav Strand,4 Morten Tryland,1 and Jon M. Arnemo2,7 1Section of Arctic Veterinary Medicine, Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science, NO-9292 Tromsø, Norway; 2 Department of Forestry and Wildlife Management, Faculty of Applied Ecology and Agricultural Sciences, Hedmark University College, Campus Evenstad, NO-2418 Elverum, Norway; 3Veterinærconsult AS, Wintherbakken 21, NO-3016 Drammen, Norway; 4Norwegian Institute for Nature Research, NO-7485 Trondheim, Norway; 5Norwegian Polar Institute, NO-9296, Tromsø, Norway; 6Direktoratet for Naturforvaltning, NO-7042 Trondheim, Norway; 7Department of Wildlife, Fish and Environmental Studies, Faculty of Forest Sciences, Swedish University of Agricultural Sciences, SE-901 83 Umea, Sweden; 8Corresponding author (email:
[email protected])
ABSTRACT: Previously published studies indicated that combinations of medetomidine and ketamine were effective for both Svalbard (Rangifer tarandus platyrhynchus) and wild Norwegian reindeer (Rangifer tarandus tarandus). Both previous studies indicated that reindeer were hypoxemic on the basis of pulse oximetry. We conducted a physiologic evaluation of these two protocols using arterial blood gases. Medetomidine (10 mg) and ketamine (200 mg) were administered by dart from the ground in Svalbard reindeer (October 2010) and from a helicopter for wild reindeer (March 2012). Of tested animals, all seven wild reindeer and five of seven Svalbard reindeer were hypoxemic before oxygen administration. Nasal oxygen insufflation (1 L/min for five Svalbard reindeer and one wild reindeer and 2 L/min for four wild reindeer) corrected hypoxemia in all cases evaluated. For reversal, all animals received 5 mg atipamezole per mg medetomidine intramuscularly. Key words: Atipamezole, immobilization, i-STAT, ketamine, medetomidine, Rangifer, reindeer.
During the past 20 yr, a large number of free-ranging, wild Norwegian reindeer (WR, Rangifer tarandus tarandus) have been captured by aerial darting. Although early captures were done with etorphine, a better quality of anesthesia was found with medetomidine-ketamine (Arnemo et al., 2011). Arnemo and Aanes (2009) did a similar study on medetomidine-ketamine anesthesia in Svalbard reindeer (SR, Rangifer tarandus platyrhynchus). Hyp-
oxemia (as indicated by pulse oximetry) following medetomidine-ketamine administration has also been reported for captive, semidomestic Norwegian reindeer, R. t. tarandus (Ryeng et al., 2001), WR (Arnemo et al., 2011), and SR (Arnemo and Aanes, 2009). Inadequate arterial oxygenation results in tissue hypoxia, which can cause cell damage to vital organs, including the brain, heart, kidneys, and liver (Caulkett et al., 1994; McDonell and Kerr, 2007). Hypoxemia, often defined as an hemoglobin oxygen saturation ,85%, is common during chemical capture of wildlife (Caulkett and Arnemo, 2007). Here, we follow up previous work (Arnemo and Aanes, 2009; Arnemo et al., 2011) by presenting more detailed clinical and physiologic effects of medetomidine-ketamine administered to free-ranging, wild Norwegian reindeer by dart syringe from a helicopter and Svalbard reindeer darted from the ground. We also evaluated intranasal insufflation of low-flow rates of oxygen for correction of arterial hypoxemia. The study was conducted during October 2010 in Adventdalen, Svalbard, Norway (78u189N, 16u339E) and during March 2012 in Hardangervidda, Telemark, Norway (59u599N, 7u449E) and Setesdal (59u249N, 7u309E). Sixteen adult SR (four male, eight female) and 10 adult female WR were captured. Capture of WR was
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approved by the Norwegian Animal Research Authority and the Norwegian Directorate for Nature Management, whereas capture of SR was approved by The Norwegian Animal Research Authority and The Governor of Svalbard. Capture of WR was done as described by Arnemo et al. (2011). They were immobilized with a combination of medetomidine (ZalopineH 10 mg/mL, Orion Corporation Animal Health, Espoo, Finland) and ketamine (KetavetH 100 mg/mL, Parke-Davis GmbH, Berlin, Germany). An initial dose of 10 mg medetomidine and 200 mg ketamine per animal was used. Animals that were not recumbent within 20 min of drug administration were redarted with an additional full dose. Once reindeer were recumbent, the helicopter landed, and the capture team waited at least 5 min before approaching. On Svalbard, reindeer were located using binoculars and approached on foot as described by Arnemo and Aanes (2009). An initial dose of 10 mg medetomidine and 200 mg ketamine per animal was used. Physiologic evaluation for both WR and SR was done as previously reported for moose (Evans et al., 2012). Recorded variables included time from sighting animal to successful darting (darting time) and time from darting to recumbency (induction time). All reindeer were maintained in sternal recumbency during immobilization. Heart rate (by auscultation of the heart), respiratory rate (counting breaths), and rectal temperature (digital thermometer) were measured immediately after capture. Animals were weighed with a portable scale. Immediately after capture and after 15 min of nasal oxygen insufflation, arterial blood samples were collected anaerobically from the auricular artery using self-filling arterial syringes with heparin (PICOTM 70, Radiometer Copenhagen, Brønshøj, Denmark) and analyzed immediately with an i-STATH 1 Portable Clinical Analyzer and i-STAT CG4+, 6+, and EC8+ cartridges (Abbott Laboratories, Abbott Park, Illinois,
USA). As previously reported (Evans et al., 2012), the i-STAT 1 analyzer was kept in an insulated box to keep it at optimum temperature (16–30 C), with warm water bottles used as needed. Wild reindeer were given 2 L/min of oxygen, except for one animal which received 1 L/min, and SR received 1 L/min. Measured variables included pH, hematocrit, partial pressure of arterial oxygen (PaO2) and carbon dioxide (PaCO2), and whole-blood concentrations of lactate, sodium (Na), potassium (K), chloride (Cl), urea, and glucose. In SR, lactate concentrations were measured with the Lactate Pro/LT-1710 (Arkray Factory Inc, KDK Corp., Japan). PaO2, PaCO2, and pH were corrected on the basis of rectal temperature. Calculated values included concentration of bicarbonate (HCO3), hemoglobin, oxygen hemoglobin saturation (SaO2%), and base excess (BE). Atipamezole (AntisedanH 5 mg/ml Orion Pharma Animal Health, Espoo, Finland) at 5 mg/1 mg medetomidine was used for reversal. Time from darting until time of administration of reversal drugs and time from reversal until standing were recorded. Hypoxemia was defined as mild (PaO258.0– 10.0 kPa), marked (PaO255.5–8.0 kPa), or severe (PaO2,5.5 kPa). Acidemia was defined as pH,7.35, and acidemia was considered marked if pH,7.20. Hypocapnia was defined as a PaCO2,4.5 kPa, and hypercapnia was defined as mild (PaCO256–8 kPa) or marked (PaCO2.8 kPa). The target PaO2 after oxygen supplementation was defined as 11–16 kPa. Variables were first tested for normality using Shapiro-Wilk test (P,0.05). Results for the first and second sample (both measured and calculated values) were compared using a paired t-test for normally distributed variables and the Wilcoxon signed-rank test for variables not distributed normally. Statistics were carried out using JMPH 9.0.2 (SAS Institute, Cary, North Carolina, USA). The ambient temperature ranged from 862 C (4–9 C) during WR captures, and 2364 C (29 C to +4 C) for SR captures.
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TABLE 1. Physiologic variables during chemical immobilization of adult, free-ranging, wild Norwegian reindeer (Rangifer tarandus tarandus) with medetomidine-ketamine, administered by dart syringe from a helicopter and remobilized with atipamezole intramuscularly in March 2012, Hardangervidda and Telemark, Norway.
Variablea
n
Before oxgyen mean6SD (min–max)
After oxygena mean6SD (min–max)
Pa
Induction (min) Weight (kg) T1 (C) P1 (beats/min) R1 (breaths/min) pH PaCO2 (mmHg) PaCO2 (kPa) PaO2 (mmHg) PaO2 (kPa) BE HCO3 (mmol/L) TCO2 (mmol/L) SaO2 (%) Lac (mmol/L) Na K (mmol/L) Glu Hct Hb
8 7 7 7 7 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5
1668 (1–31) 7467 (62–83) 40.160.5 (39.1–40.9) 4065 (32–50) 38621 (20–60) 7.3560.03 (7.29–7.38) 43.363.7 (38.5–47.1) 5.760.5 (5.1–6.3) 5767 (43–63) 7.660.9 (5.7–8.4) (22) 63 (28 to +3) 23.163.0 (17.7–27.0) 2463 (19–28) 8068 (63–86) 8.662.8 (3.3–11.0) 14061 (139–141) 3.560.1(3.3–3.6) 197638 (153–241) 42–4 (37–47) 14.4–1.2 (12.6–16.0)
N/A N/A 40.160.6 (39.2–40.9) 3766 (27–44) 33616 (20–60) 7.3560.04 (7.32–7.41) 52.165.6 (42.7–57.9) 6.960.8 (5.7–7.7) 121622 (89–147) 16.162.9 (11.9–19.6) 362 (1–7) 28.062.5 (25.8–31.8) 3062 (27–33) 9762 (94–99) 6.361.3 (4.2–7.7) N/A N/A N/A N/A N/A
N/A N/A NSD NSD NSDb NSD 0.0476 0.0476 0.0037 0.0037 0.0138 0.0177 0.0141 NSDb 0.0041 N/A N/A N/A N/A N/A
a
N/A 5 not applicable; NSD 5 no significant difference; min–max 5 minimum to maximum; T1 5 temperature; P1 5 pulse; R1 5 respiration; PaO2 5 partial pressure of arterial oxygen; PaCO2 5 partial pressure of carbon dioxide; BE 5 base excess; TCO2 5 total carbon dioxide; SaO2 5 oxygen hemoglobin saturation; Lac 5 lactate; Glu 5 glucose; Hct, hematocrit; Hb 5 hemoglobin.
One WR and one SR required a second dart, and these animals were excluded from analysis. Two SR required extra drugs, and these were given 100 and 250 mg ketamine intramuscularly. In a previous study (Arnemo and Aanes, 2009), no significant differences between males and females were found, so data were pooled for SR. All animals were completely immobilized with good muscle relaxation. Recoveries were calm, and animals stood up and walked away in a coordinated manner. After 6 mo, all WR were alive with functioning GPS collars, except for one collar that stopped working after 3 mo. SR were in an area frequented by hikers and tourists, and no reports of dead reindeer were received. Physiologic variables and arterial blood gas results are summarized in Tables 1 (WR) and 2 (SR). For WR, arterial samples were collected from seven ani-
mals immediately at capture and repeated after 1564 (10–23) min with intranasal oxygen insufflation. Six SR were sampled initially and again after 2168 (15–31) min with intranasal oxygen insufflation. In two SR, errors were received on the oxygen variables (PaO2 and SaO2): one on the presample and one on the postsample. These two animals were included in all analyses not involving PaO2 and SaO2. Wild reindeer had significantly higher body temperature than SR both before (P,0.0001) and after (P,0.0001) oxygen supplementation, although neither had a significant difference between the before and after sampling (Tables 1, 2). On initial sampling, all seven WR were hypoxemic, with three classified as mild and four as marked. Four were acidemic. One of seven reindeer was mildly hypercapnic. After oxygen treatment in five animals (four receiving 2L/min and one
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TABLE 2. Physiologic variables during chemical immobilization of Svalbard reindeer (Rangifer tarandus platyrhynchus) immobilized by ground darting with medetomidine-ketamine in October 2012, Adventdalen, Svalbard, Norway.
Variable
n
Before oxgyen mean6SD (min–max)
After oxygen mean6SD (min–max)a
Pa
Induction (min) Weight (kg) Temp (C) Pulse (beats/min) Respiration (breaths/min) pH PaCO2 (mmHg) PaCO2 (kPa) PaO2 (mmHg) PaO2 (kPa) BE HCO3 (mmol/L) TCO2 (mmol/L) SaO2 PO (%) SaO2 i-STAT (%) Lac (mmol/L) Na K (mmol/L) Glu Hct Hb
14 16 16 16 16 6 6 6 4 4 5 6 6 6 4 6 6 6 6 6 6
1668 (1–31) 75613 (53–102) 38.360.6 (37.6–39.9) 3366 (24–44) 1364 (6–20) 7.4260.05 (7.33–7.49) 49.867.5 (42.4–61.4) 6.661.0 (5.7–8.2) 67618 (41–87) 8.962.4 (5.5–11.6) 763 (3–11) 31.462.5 (27.3–34.5) 3363 (28–36) 8866 (77–96) 89633 (70–97) ‘‘Low’’b 13563 (131–140) 4.260.4 (3.7–4.9) 214618 (180–235) 3963 (35–43) 13.361.1 (11.9–14.6)
N/A N/A 38.160.6 (37.1–39.4) 40614 (20–62) 1463 (8–20) 7.4660.10 (7.38–7.65) 48.7610.9 (31.7–63.4) 6.561.5 (4.2–8.5) 152682 (97–295) 20.2610.9 (12.9–39.3) 1064 (5–15) 33.363.0 (29.4–37.7) 3563 (31–40) 9365 (83–99) 9961 (98–100) ‘‘Low’’b 13563 (130–139) 4.660.8 (3.8–6) 254631 (208–288) 3763 (33–41) 12.661.0 (11.2–13.9)
N/A N/A NSD NSD NSDc NSDc NSD NSD NSDc NSD 0.0050 0.0125 0.0335 NSD NSD N/A NSD 0.0441 0.0436 0.0171 0.0156
a
N/A 5 not applicable; NSD 5 no significant difference; min–max 5 minimum to maximum; PaO2 5 partial pressure of arterial oxygen; PaCO2 5 partial pressure of carbon dioxide; BE 5 base excess; Temp 5 temperature; TCO2 5 total carbon dioxide; SaO2 5 oxygen hemoglobin saturation; PO 5 pulse oximetry; Lac 5 lactate; Glu 5 glucose; Hct, hematocrit; Hb 5 hemoglobin.
b
With the lactate pro, lactate under 0.8 read as ‘‘low.’’ One animal in each group (before and after oxygen) received a value of 0.8, whereas all others were ‘‘low’’ or ,0.8).
c
Nonnormally distributed data, Wilcoxon signed-rank test used to compare means.
receiving 1L/min), no animals were hypoxemic, three were mildly acidemic, and four were mildly hypercapnic. Only two were within the target range for PaO2 (11.9 kPa for the one receiving 1 L/min and 14.9 kPa for one receiving 2 L/min). The other three were above the target (16.4, 17.7, and 19.6 kPa). In SR, on initial sampling, one animal had an erroneous PO2 reading (air bubble in sample), and four of the six remaining were hypoxemic, with two animals exhibiting marked hypoxemia. Only one animal was mildly acidemic (pH 7.34). Five of seven were hypercapnic, with marked hypercapnia in one animal. Six of the seven were sampled after oxygen supplementation, with one sample giving an erroneous PaO2 and SaO2 reading. None of the remaining five
were hypoxemic, with two being in the target range (12.9 and 13.9 kPa) and three being well above (16.3, 18.9, and 39.3 kPa). Four of six were hypercapnic, with marked hypercapnia in one animal (a different individual than before treatment). No animals were acidemic after treatment. The WR were visibly excited and stressed from helicopter darting, whereas the SR remained calm, and other members of the herd calmly walked away from the immobilized animal. All reindeer in our study were hypoxemic upon capture, and all that received supplemental oxygen had normal to high oxygen levels afterward. With an oxygen flow rate of 1 L/min in SR (n55) and 2 L/ min in WR (n54), animals were well within or above the target range, so it is
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likely that 0.5 L in SR and 1 L in WR would be sufficient; however, further studies are needed to confirm this. The significantly higher body temperature in the WR can be attributed to stress associated with helicopter chasing and running. The Svalbard reindeer were calm and not concerned by the darter’s presence and often walked only 10–20 m away when they noticed the presence of the researchers. The SR exhibited lower and the WR higher temperatures than found in captive semidomestic reindeer (mean 39.1 C, 95% CI, 38.9–39.3 C; Ryeng et al., 2001), likely indicating relative stress levels for captures in these three types of reindeer. Medetomidine-ketamine is an effective drug combination for immobilization of free-ranging adult wild Norwegian reindeer and Svalbard reindeer (Arnemo and Aanes, 2009; Arnemo et al., 2011). However, all animals exhibited mild to marked hypoxemia, likely caused by the relatively high doses of medetomidine presented here, readily corrected with intranasal oxygen supplementation. Therefore, oxygen supplementation is recommended for these subspecies when anesthetized with medetomidine-ketamine. We thank Marit Madderrom and Brage B. Hansen for contributing to the captures of Svalbard reindeer. This study was funded by the Norwegian Directorate for Nature Management, the Norwegian School of Veterinary Science, Hedmark University College Morris Animal Foundation, the Norwegian Polar Institute, and the Sval-
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bard Science Forum (Arctic Field grant RIS 3753). LITERATURE CITED Arnemo JM, Aanes R. 2009. Reversible immobilization of free-ranging svalbard reindeer (Rangifer tarandus platyrhynchus) with medetomidineketamine and atipamezole. J Wildl Dis 45:877– 880. Arnemo JM, Evans AL, Miller AL, Os Ø. 2011. Effective immobilizing doses of medetomidineketamine in free-ranging, wild Norwegian reindeer (Rangifer tarandus tarandus). J Wildl Dis 47:755–758. Caulkett NA, Arnemo JM. 2007. Chemical immobilization of free-ranging terrestrial mammals. In: Lumb & Jones’ Veterinary Anesthesia and Analgesia, 4th Ed., Tranquilli WJ, Thurmon JC and Grimm K (eds.). Blackwell Publications, Ames, Iowa, pp. 807–830. Caulkett NA, Cribb PH, Duke T. 1994. Cardiopulmonary effects of medetomidine-ketamine immobilization with atipamezole reversal and carfentanil-xylazine immobilization with naltrexone reversal: A comparative study in domestic sheep (Ovis ovis). J Zoo Wildl Med 25:376–389. Evans AL, Fahlman A, Ericsson G, Haga HA, Arnemo JM. 2012. Physiological evaluation of free-ranging moose (Alces alces) immobilized with etorphine-xylazine-acepromazine in northern Sweden. Acta Vet Scand 54:77. McDonell WN, Kerr CL. 2007. Respiratory system. In: Lumb & Jones’ Veterinary Anesthesia Analgesia, 4th Ed, Tranquilli WJ, Thurmon JC and Grimm KA (eds.). Blackwell Publishing, Ames, Iowa, 1096 pp. Ryeng KA, Larsen S, Ranheim B, Albertsen G, Arnemo JM. 2001. Clinical evaluation of established optimal immobilizing doses of medetomidine-ketamine in captive reindeer (Rangifer tarandus tarandus). Am J Vet Res 62:406–413.
Submitted for publication 2 March 2013. Accepted 3 May 2013.
