In case the elephant does not cooperate voluntarily with the manipulations needed for the diagnosis or treatment the animal should be sedated (including herd mates if needed to reduce stress in the herd)
Standing sedation can be performed using xylazine or (preferred) detomidine in combination with butorphanol. Medetomidine works as good as detomidine, but is more expensive.
Young elephants need the higher dose range compared to older elephants.
Elephants that are excited can be premedicated with azaperone (Asian elephant 0.024-0.038 IM, African elephant 0.056-0.107 IM, IV).
Detomidine 0.01-0.022 mg/kg IM (can be reversed by atipamezole at 3-5 times the dose of detomidine)
Butorphanol 0.045-0.075 mg/kg given at same time as detomidine. Butorphanol can be reversed with naltrexone at 2.5-5 times the dose of butorphanol in emergency situations, but reversal is not essential and should preferably not be carried out if the calf is considered to be in pain.
Alternative option for sedation (if the above mentioned drugs are not available):
Xylazine: 0.04-0.08 mg/kg IM for adult Asian elephants and 0.08-0.1 mg/kg for African elephants.
Juvenile Asian elephants: 0.09–0.15 xylazine mg/kg IM) Jansson 2021)
If insufficient sedation is obtained by xylazine alone, an additional (low) dose of ketamine (0.03 – 0.06 mg/kg) can be given IM or IV.
Xylazine can be reversed with yohimbine (0.073-0.098 mg/kg slowly IV) or atipamezole (0.1 x xylazine dose IM or 30/70 IV/IM)
If a young calf needs to be sedated, it may be necessary to sedate the dam or other adult herd mates so they are not stressed during manipulations on a calf. This can be done by the administration of:
Butorphanol 0.006 mg/kg IM and detomidine 0.0026 mg/kg IM (In adult female Asian elephants, 20mg butorphanol and 10mg detomidine have been effective)
Sedation can be reversed as described above but is not necessary
Alternatively, xylazine (0.04–0.08 mg/kg) or other sedative agents (e.g. Azaperone at 0.024–0.038 mg/kg) can be used if detomidine is unavailable.
Laubscher LL et a. 2021 described a fixed drug combination of butorphanol, azaperone and medetomidine (BAM) for African elephants. The dose is given per cm shoulder height.
The composition of this anesthetic mixture is: 30 mg/ml butorphanol, 12 mg/ml azaperone, and 12 mg/ml medetomidine. The use of this combination can be recommended in captive, trained African elephants at a dose of 0.006 6 ± 0.001 ml/cm shoulder height.
When the elephant becomes sedated, the following signs can be observed:
Relaxation of the trunk; the tip of the trunk will touch the ground.
Relaxation of the penis and (less obvious) relaxation of the vulva.
It is important to cover the eyes with gauze pads (taped to the skin with Leucoplast or ducttape) and put cotton plugs in the ears. This will deepen the sedation and reduce the risk of sudden wakening.
One should always be prepared that the elephant may wake up. Safety procedures need to be discussed in advance with everyone involved in the procedure.
Summary agonist - antagonists
Xylazine is reversed by yohimbine: 0,05-0,13 mg/kg IV
,, ,, ,, ,, atipamezole: 0.1 x xylazine dose
Detomidine is reversed by: atipamezole: 3-5 times the detomidine dose IM or slow IV (30/70 IV/IM)
Butorphanol is reversed by naltrexone: 2.5-5 x butorphenol dose IV. Skip naltrexone if pain relieve is desirable. The naltrexone dosage provided by Laubscher LL et a. 2020 is much lower: 1 mg naltrexone per mg butorphanol.
Fowler M.E. and Mikota S.K. 2006. Chemical restraint and general anesthesia. In: Biology, medicine and surgery of elephants. Blackwell Publishing.Jansson T., Vijitha P.B., Edner A., and Fahlman A. 2021. Standing sedation with xylazine and reversal with yohimbine in juvenile Asian elephants (Elephas maximus). Journal of Zoo and Wildlife Medicine, 52(2) : 437-444.
Liesel L. Laubscher, Silke Pfitzer, Peter S. Rogers, Lisa L. Wolfe, Michael W. Miller, Aleksandr Semjonov, Jacobus P. Raath. 2021. Evaluating the use of a butorphanol-azaperone-medetomidine fixed-dose combination for standing sedation in African elephants (Loxodonta africana). J. of Zoo and Wildlife Medicine, 52(1):287-294 (2021)
Neiffer D.L. , Miller M.A., Weber M., Stetter M., Fontenot D.K., Robbins P.K., and Pye G.W. 2005. Standing sedation in African elephants (Loxodonta africana) using detomidine–butorphanol combinations. Journal of Zoo and Wildlife Medicine 36(2): 250–256, 2005.
E. Wiedner. 2015. Proboscidea. In: Fowler's Zoo and Wild animal Medicine 8.
General anesthesia is required in those cases where standing sedation alone or in combination with local anesthesia does not suffice for the intervention that needs to be done. We can devide the indications in:
Immobilization for painful procedures
Capture immobilization is mostly done in range countries. However, the escape of a captive elephant may also require capture immobilization. Elephants from this category have not been prepared for the immobilization. This means that they have been able to take food an water shortly prior to the immobilization. It aslo nmeasn that the circumstances have not (or insufficiently) been prepared for the procedure as compared to an immobilization under full captive conditions.
If possible, prepare a safe area for the people and elephant involved. Avoid an area with water and select a place that is reachable for heavy equipment. Provide shadow whenever possible. Make sure you can ccol the elephant with cold water when necessary. Heavy equipment to position the elephant in lateral recumbancy may be needed, as sternal recumbancy is highly associated with anesthetic death. If an elephant has gone down in sternal position and cannot be rolled over in lateral recumbancy, the anesthesia must be reversed immediately.
Whenever possible, provide a soft bedding, preferablyadeep sand layer covered by a deep layer of straw or matrasses. Straps or belts are required in case the elephant needs to be rolled over. It is important to thraw them under the elephant before the animal will go down. It helps if the elephant lays on sand and straw to get straps or a belt under the elephant's body with the help of a hooked steel wire.
To protect the tusks against fractures, a car tyre can be placed under the head just before the elephant goes down.
Trained elephant can be anesthetized when brought in sternal or lateral recumbency. Once the drugs have induced general anesthesia, the elephant should be rolled over into lateral recumbency.
Especially in trained elephants, ropes can be used to guide the elephant into lateral recumbency.
Trained captive African elephant brought under general anesthesia while guided by ropes. Courtesy: Osterhaus and Fagan.
Elephants should be fastened for 24-48 hours prior to anesthesia. Water should be withheld for 24 hours before the procedure.
Capture immobilization is mostly done in range countries. The escape of a captive elephant may also require capture immobilization. Elephants from this category have not been prepared for the immobilization. This means that they have been able to take food an water shortly prior to the immobilization. It aslo nmeasn that the circumstances have not or insufficiently been prepared for the procedure as compared to an immobilization under full captive conditions.
Preparation: if possible, prepare a safe area for the people and elephant involved. Avoid an area with water and select an area that is reachable for equipment. Provide shadow whenever possible. Make sure you ccool the elephant with old water when necessary. Heavy equipment to position the elephant in lateral recumbancy may be needed, as sternal recumbancy is highly associated with anesthetic death. If an elephant has gone down in sternal position and cannot be rolled over in lateral recumbancy, the anesthesia must be reversed immediately.
Whenever possible, provide a soft bedding, preferably sand covered by a deep layer of straw or matrasses. If straps are required in case the elephant needs to be rolled over, it is important to thraw them under the elephant just before the animal will go down. It helps if the elephants lays
on sand and straw to get straps or a belt under the elephant's body with the help of a hooked steel wire.
Drugs used for general anesthesia:
Captive elephants that are excited can be premedicated with azaperone (Asian elephant 0.024-0.038 IM, African elephant 0.056-0.107 IM, IV).
Fast acting immobilizing drugs that are used for capture immobilization:
Etorphine: 0.002-0.004 mg/kg IM (Asian elephant) and 0.0015-0.003 mg/kg IM (African elephant)
Carfentanil: 0.002-0.004 mg/kg (Asian elephant) and 0.0013-0.0024 mg/kg IM (African elephant)
These drugs can be antagonized with naltrexone 0.004 mg/kg IM (or 50/50 IV/IM)
If carfentanil and etorphine are not available, xyalzine (0.1 mg/kg) and ketamine (0.3-0.7 mg/kg) can be given together. The disadvantage is the large volume required for an adult elephant. For capture immobilization this combination is therefore not recommended.. At the end of the procedure xylazine can be reversed with atipamezole (0.1 x dose of xylazine IM or slowly IV) or yohimbine (0.05-0.13 mg/kg IV).
Once in lateral recumbancy, the elephant can be intubated and anesthesia can be maintained on isoflurane or halothane (1.5-3%).
Inhalation anesthesia and intubation:
Intubation in elephants is straightforward. A 30-50 mm diameter cuffed endotracheal tube can be inserted into the trachea. A rope around the lower jaw can be used to open the mouth. A gloved hand can reach the epiglottis and advance a lung tube (e.g. stocha tube for horses) into the trachea, while pushing the soft palate upward. Once in place, the endotracheal tube can be advanced into the trachea guided by the smaller tube.
A special portable pressure ventilater has been developed and described by William et al. Jeff Zuba made some modifications to this design, which is now commercially available (http://www.incaseofanesthesia.com/Home_Page.html).
Schematic overview of a portable pressure ventilation device for elephants.
"Zuba" ventilator used in an adult African elephant under field conditions
Captive African elephant intubated for gas anesthesia using a "Zuba" ventilator.
Under less favorable circumstances when a pressure ventilator is not available, intubation can be done in the trunk using 2 cuffed horse endotracheal tubes and 2 separate (portable) anesthetic machines. The advantages of this method are the easy intubation and the ample space in the oral cavity in the absence of the large tube. However the disadvantages are substantial:
Two tubes increase the airway resistence
Risk of regurgitation and aspiration of stomach contents
An elephant can breath through its mouth, which will bypass the inhalation of the anethetic gas
General anesthesia in a captive Asian elephant using trunk intubation (Rotterdam Zoo, 1989)
Pulse oximetry is a reliable tool for monitoring heart frequency and venous oxygen saturation. A capnagraph is recommended to monitor the respiration. If not available, one individual should be assigned just to monitor respiratory rate and depth. ECG and arterial blood gases are recommended. As hypotension is quite common in anesthetized elephants, blood pressure measurement is also recommended. Hypotension has been treated successfully with ephedrine and dobutamine.
Weak or debilitated animals may need help to get back on their feet during recovery. A deep sand layer is essential for the elephant to getting grip on the ground. A crane may be needed to lift the animal fromthe ground, using straps or belts applied around the body.
Fowler M.E. and Mikota S.K. 2006. Chemical restraint and general anesthesia. In: Biology, medicine and surgery of elephants. Blackwell Publishing.
E. Wiedner. 2015. Proboscidea. In: Fowler's Zoo and Wild animal Medicine 8.
Zuba J.R., Osterhaus J.E. 2012. Anesthetic complications and clinical intervention in opiod anesthetized captive elephants. In: Proceedings of the AAZV Conference, Oakland (1-6).
Epidural anesthesia in elephants is recommended when a vaginal vestibulotomy is performed in order to reduce tail movements of the elephant and provide additional analgesia in the perineal region.
Restrain the elephant as appropriate in a chute and sedated if necessary.
Disinfect the injection site.
Move the tail up and down to determine the position of the most mobile intercoccygeal space.
Inject local anaesthetic (2% Lidocaine) into the skin over the injection site.
Palpate the intercoccygeal space wearing a sterile glove and insert the needle (14 gauge, 3 inch) at approximately a 60 - 70 degree angle cranially.
The epidural space is about 6.5 cm below the skin surface.
Inject Lidocaine: 30 ml was sufficient to produce tail relaxation in a 3,000 kg elephant, and the elephant remained standing.