Vomiting in Llamas During Capture and Chemical Immobilization
The llama (Lama glama) is a domesticated relative of the guanaco (Lama guanicoe) and one of the South American members of the camel family, Camelidae (order Artiodactyla). This group of animals includes dromedary camels, Bactrian camels, wild Bactrian camels, llamas, alpacas, vicuñas, and guanacos.1 Llamas are also known as lamoids or New World camelids, which are terms for the South American members of the camelid family (e.g., llamas, alpacas, vicunas, guanacos).
Like camels, lamoids originated in North America over 40 million years ago, with lamoids migrating to South America and camels migrating west via the Bering Strait and later becoming extinct in North America.2 Unlike camels, llamas and other lamoids do not have the iconic back humps.
Llamas and other lamoids have been so widely domesticated over the last 6,500—7,000 years that there are few if any occurring in the wild. Today, domesticated llama herds are found in the Andean highlands of Bolivia, Peru, Colombia, Ecuador, Chile, and Argentina. They are also farmed, primarily for their fleece, in a number of other countries.2,3 While most llamas are white in color, they may also be solid black or brown, or white with brown or black markings.
Llamas are slender-bodied, with long legs, long necks, short tails and large ears. The llama is the largest of the New World camelids. They average 45 inches in height at the shoulder; adult males weigh between 300 and 400 pounds, and adult females weigh between 230 and 350 pounds.3
In their South American range, llamas are used mostly as pack animals. A 250 pound llama is able to carry a load of 100—130 pounds for around 15 to 20 miles a day. Often however, a llama carrying too heavy a load will refuse to move. They may also lie on the ground and spit, hiss, or kick until the load is lessened. Apart from this, llamas are known for being gregarious and easy to handle. Llamas are also used for food, wool, hides, tallow for candles, and dried dung for fuel.2
For food, llamas graze mostly on grass, regurgitate their food and chew it as cud. Unlike cows however, they are pseudo ruminants with a three-chambered stomach (unlike true ruminants such as cows, which have four-chambered stomachs). Llamas can also survive on other plants, and require little water. This makes them particularly useful in dry, mountainous terrain. Llamas breed in the late summer and fall. Their gestation period is approximately 11 months, after which the female gives birth to one young.3
Vomiting and Anesthetic Aspiration Risks in Llamas
In both domestic and exotic animals, vomiting is one of the more common potential post-sedation and post-anesthesia complications. It is not uncommon for an animal to vomit once or twice after a surgical procedure. However, if the vomiting continues, it can be a sign of an emerging complication. A far more serious complication involves vomiting that occurs during a procedure, since this can pose grave risks due to anesthetic aspiration.
Anesthetic aspiration involves a llama vomiting food from its stomach during a surgical procedure, which subsequently infiltrates into the lungs. This can lead to aspiration pneumonia. Modern protocols for anesthesia and sedation in wildlife are generally safe, however, respiratory complications such as anesthesia-related aspiration and pneumonia can be fatal.4
Simple aspiration is the entry of liquid or solid material into the trachea and lungs. This can occur when patients without sufficient laryngeal protective reflexes (as a result of sedation or anesthetic agents) regurgitate gastric contents. “Pulmonary syndromes of differing severity can result, ranging from mild symptoms such as hypoxia to complete respiratory failure and acute respiratory distress syndrome (ARDS).”4 In some cases, cardiopulmonary collapse and death can occur. Related pulmonary syndromes can include acid-associated pneumonitis, particle-associated aspiration (airway obstruction) or bacterial infection. Which of these develops generally depends upon the composition and volume of the aspirate.
Acute intraoperative aspiration is aspiration during a surgical procedure, and this is a potentially fatal complication with significant associated morbidity. Llamas undergoing thoracic surgery are at increased risk for anesthesia-related aspiration. Awareness of the risk factors, predisposing conditions, precautions to decrease risk and immediate management options are imperative to reducing risk and optimizing outcomes associated with this complication.4
Mitigating Risks for Vomiting and Aspiration
The veterinary care of domestic and non-domestic hoofstock has become commonplace due to the integration of veterinary medicine in wildlife management programs, zoological collections, exotic animal ranching expansions and the private collection of wildlife species.5 As a result, research and wildlife veterinarians are required to amass the knowledge associated with safely anesthetizing and handling animals such as llamas.
The sedation and anesthesia of llamas requires the knowledge the pharmacology of the drugs being used, as well as the variation in dose response among these animals. A major challenge—and one which impacts potential complications such as anesthetic aspiration—is correlating the available pharmaceutical tools with the environment and conditions, as well as the procedures and events preceding, during, and following the anesthetic event.6 For example, detailed biological information on individual animals may be readily available on a farm or in a zoo setting, whereas this is often unavailable in the field, thereby complicating such things as calculating drug dosages.
The quality of sedation, anesthesia and analgesia achievable in llamas and other wildlife species has been made possible through the availability of new, receptor-specific and highly potent agonist-reversible pharmaceuticals and improved knowledge in the area of CNS receptors. Such developments have lowered the risk factors for many potential complications, such as vomiting and aspiration.
Llamas and Chemical Immobilization
Due to their widespread domestication, nearly all camelids are tractable, thus physical restraint and local anesthetic techniques are frequently used to provide immobility and analgesia. In llamas, general anesthesia techniques are similar to those for ruminants and horses.6,7 Regurgitation of compartment one (C1) of the stomach contents and postoperative nasal congestion and associated respiratory distress postextubation are potential hazards associated with anesthesia. In most cases, recovery from anesthesia is generally uneventful.7
Monitoring core body temperature is essential in llama anesthesia.6 Until the more recent use of formulated drugs (e.g., combinations of α2-agonists such as medetomidine, detomidine, xylazine and their reversal agents), opioids were the mainstay of llama anesthesia in wildlife and captive care.5
Preventing and Managing Anesthetic Vomiting in Llamas
Guidelines for the preparation of llamas for anesthesia and surgery include decreasing the size and pressure in C1 before anesthesia, withholding food for 12 to 18 hours in adults and withholding water for up to 12 hours. Withholding food or water in neonates is not recommended, as this increases the risk of dehydration and hypoglycemia. Llamas younger than one month of age rarely regurgitate during anesthesia. It is also recommended that camelids be orotracheally intubated for any procedure lasting more than 20 minutes.7
Positioning of the llama is important to reduce the likelihood of regurgitation. It is recommended that the animal’s head is kept elevated above the stomach if possible. The literature also advises against rolling an anesthetized llama dorsally unless an endotracheal tube has been placed. For the prevention of anesthetic aspiration, histamine (H2) antagonists such as cimetidine, famotidine, nizatidine, and ranitidine and proton pump inhibitors (PPIs) such as dexlansoprazole, esomeprazole, lansoprazole, omeprazole, pantoprazole, and rabeprazole have been shown to be effective in increasing the pH and reduce the volume of gastric contents.4 Prokinetics such as domperidone, metoclopramide, erythromycin and renzapride promote gastric emptying and may reduce the risk of aspiration.6
In the event of intraoperative aspiration in a sedated or anesthetized llama, the first step in successful management is the timely recognition of gastric content in the oropharynx or the airways.4 The animal’s head should be positioned with the mouth below the level of the torso. Stomach tubes can be placed in the esophagus to prevent aspiration. Orotracheal and endotracheal suctioning should be carried out (either before or after orotracheal intubation) depending on whether regurgitation continues and if the airway is visible.
The animal’s airway should be secured as rapidly as possible to prevent further contamination and to facilitate airway clearance.6 Flexible bronchoscopy is helpful in orotracheal and endotracheal suctioning, and having a flexible bronchoscope at the ready is a prudent measure. If particulate matter is present in the airway, rigid bronchoscopy may be needed.4-6
4Nason, K. Acute Intraoperative Pulmonary Aspiration. Thoracic surgery clinics vol. 25,3 (2015): 301-7.
5Lance, W. Exotic Hoof Stock Anesthesia and Analgesia: Best Practices. In: Proceedings, NAVC Conference 2008, pp. 1914-15.
6Kluger M.T., et. al. Crisis management during anaesthesia: regurgitation, vomiting, and aspiration. Quality & safety in health care. 2005;14(3): e4.
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