Restraint, physical examination and venipuncture techniques in reptiles (Proceedings)
Most snakes can be easily captured directly out of the carrier or cage they are in. If the snake is aggressive, it may be necessary to use a towel along with leather gloves to safely capture it. In these cases, it is easiest to gently toss the towel over the snake and find the head.
Capture and restraint
Most snakes can be easily captured directly out of the carrier or cage they are in. If the snake is aggressive, it may be necessary to use a towel along with leather gloves to safely capture it. In these cases, it is easiest to gently toss the towel over the snake and find the head. Once the head has been isolated and restrained, the snake can be safely taken out of the enclosure. If the snake is extremely aggressive or if it is a venomous snake, a snake hook should be used to pin down the head of the snake long enough to safely grasp its head and body. Improper use of the snake hook can cause trauma to the patient; therefore, extreme caution should be taken.
Snakes are commonly brought into the clinic in pillowcases. It is important that the veterinarian or technician does not just open the pillowcase and quickly pull the snake out (especially if unfamiliar with the patient). It is important to first know what type of snake is in the pillowcase. To safely remove the snake from the pillowcase, first find the snake's head and gently grasp it from the outside of the pillowcase. Once the snake is restrained, the restrainer should put his or her free hand into the pillowcase and transfer the head to the "free hand." After this is accomplished, it should now be safe to take the entire snake out of the pillowcase.
It is important to gently hold the snake directly behind the head with one hand (so it cannot turn around and bite!) and support the body with the other hand. If the snake is large, more than one person may be needed to restrain it. A good rule of thumb is one person per 3 ft of snake.
Lizards can be challenging animals to both capture and restrain. Smaller lizards are generally easy to capture but can be difficult to restrain because they tend to wiggle and squirm while they are being held. Most small lizards can simply be picked up with both hands and taken out of the enclosure. This is also true of the larger lizard species as well. However, some of the larger lizards can be both difficult to capture and restrain, especially if they are aggressive. If the lizard is aggressive, a towel or blanket along with leather restraint gloves should be used. It is important to remember that lizards can scratch and bite when they are scared or nervous. Therefore, it is a good idea to wear long sleeves when possible and always keep track of where the head is. Long-necked lizards (i.e., monitors) can easily turn around and bite if their head is not properly restrained during capture. Keeping one hand on the neck, just behind the base of skull, will help prevent getting bitten. Many species of lizards have a natural predatory response to voluntarily "drop" or autotomize their tail in an attempt to escape predation. It is a good rule of thumb to never capture any species of lizard by their tail.
In general, lizards can be restrained by placing one hand around the neck and pectoral girdle region while the other hand can be used to support the body near the pelvis. Although it is sometimes impossible, try to avoid smashing down and damaging the dorsal spines of lizards such as iguanas when they are being restrained. It is also important to remember that not all lizards have durable and tough skin. Some lizards such as geckos have extremely delicate skin that can easily be damaged by capture and restraint (make sure only soft towels are used on geckos).
Although chelonians (i.e. turtles and tortoises) are usually the easiest to capture, they are the hardest to restrain. Unless working with extremely large tortoises, most chelonians can just be picked up with both hands and placed on the exam table. When examining large tortoises (i.e. several kilograms), it is easiest to set up an exam area within the animal's enclosure or on the floor in the clinic's exam area. Since there is such a great deal of variation in size and strength, restraint techniques may vary between small and large chelonians. Once the animal's body is under control, it is imperative that the head is properly restrained. Although this is relatively easy when the animal is sick, it can be difficult on strong healthy chelonians, especially large tortoises and box turtles.
There are several ways the restrainer can gain control of the animal's head. Many turtles and tortoises are very curious. If they are set down on the table or the ground, they may just start walking around to check things out. If this is the case, the technician can just walk up to them and grasp their head with one hand while restraining the body with the other hand. To keep control of the head, it is best to position your thumb on one side of the cranial portion of the neck and position the rest of your fingers (or just the index finger for smaller species) on the other side of the neck just behind the base of the skull. Healthy chelonians are strong so it may take a lot of constant but gentle force to keep the turtle or tortoise's head out of the shell. If the animal is extremely active, an additional person may be necessary to help restrain the limbs and body.
Another way to gain control of the head is by trying to coax the animal out of its shell. Many chelonians will extend their head out of the shell if food is offered to them or if they are placed in a container of shallow warm water. Once the head is extended, the same techniques mentioned above can be used to gain and keep control of the animal's head. If these techniques fail, it may be possible to slip a small blunt ear curette or spay hook under the horny portion of the upper beak, known as the rhinotheca. Once the probe has been placed, it can be gently pulled back to extend the neck to a position for the restrainer to grasp. It is important to note that this technique can be dangerous. The beak can be chipped or broken if the animal struggles or is in poor health. If a spay hook is the tool of choice, it may be a good idea to pad the hooked portion of the instrument. Padding can simply consist of tape or an elastic wrap cut to the appropriate size. It is important to note that caution should be taken when dealing with any aquatic turtle, especially snapping turtles. These species of turtles have a tendency to bite, and many of the larger turtles can cause serious bodily harm to the people working with them.
Box turtles can be the most challenging chelonians to properly restrain. Since box turtles have a hinge on their plastron, many species are able to completely tuck themselves into their shells. The easiest way to extend their head is to gently prop open the cranial portion of the carapace (upper shell) and the plastron (lower shell). Extreme care must be taken when trying to prop the shell open. It is suggested that a well-padded object be used when attempting this. This will help avoid traumatizing or fracturing the shell. Another way to extend a box turtle's head is to grasp one of the forelimbs, keeping the leg extended out of the shell until the head can be successfully pulled out and properly restrained. This method works well because once the leg is extended, the turtle will usually not close its' shell down on its' own leg. It is important to remember that any of these capture and restraint techniques can potentially cause a fair amount of stress to the turtle or tortoise. If initial attempts at capture and restraint are not successful, chemical restraint may be necessary for any reptile, especially large tortoises and box turtles.
The reptile physical examination
Performing a physical examination on reptiles is similar to performing a physical examination on most mammalian species. When working with any exotic species, all items needed for the physical examination should be ready and within reach. This will help decrease the time in hand and hopefully provide a less stressful experience for both the animal and the veterinary staff. It is a good rule of thumb to perform a visual pre-capture and restraint physical examination. This can give you a good idea of what the animal's attitude and mentation is before it has been potentially stressed by handling.
One of the easiest ways to perform a good physical examination is to start at the head and work your way down to the tail. This method will help ensure that nothing is overlooked. During your physical examination, the eyes, ears, and oral cavity should be thoroughly examined. The eyes should be bright, clean, and free of any discharge. A pen light and ophthalmoscope should be used to visually observe and examine the eyes. The sclera should be observed for any signs of redness or irritation. Any opacity should also be noted during the ophthalmologic examination. Lastly, a pupilary lens response (PLR) may also be noted. Since the eye consists of voluntary striated skeletal muscle, it is not uncommon for a PLR to be absent. The ears or tympanic membranes should be observed with a pen light during the physical examination. The ears or tympanum should be clean, clear, and free of any debris.
A thorough examination of the oral cavity is an important part of performing a complete physical examination. The oral cavity can be safely opened with either porous tape stirrups or a soft plastic instrument such as a spatula. Metal speculums can be used, but caution should be taken to avoid causing trauma to the mouth. The oral cavity should be moist, pink (sometimes mucus membranes in snakes are paler then one would expect – pale mucus membranes could be a sign of a medical problem, but many times this coloration is considered "normal") and free of any lesions. During the oral examination, the mouth should be observed for any signs of erythema, stomatitis, fractured teeth, and any evidence of plaques on the mucus membranes. As you move down the body, the thoracic and coelomic cavities should be palpated. Palpation of the extremities and tail should then follow. The same techniques used to palpate dogs and cats can be used to palpate most reptiles. It is important to note any abnormalities such as soft tissue swellings, space occupying masses such as urinary calculi, developing eggs, neoplasia, and any current or old injuries such as fractures, burn wounds, or other types of trauma.
In snakes, usually the heart, gallbladder, ribcage and either prey items or feces can be palpated. In lizards, it is sometimes difficult to palpate many of the organs. In some of the larger lizards, the kidneys can be palpated via a rectal examination. If you can palpate the kidneys without a rectal examination, there is usually a problem. The kidneys sit in the pelvic girdle and are almost impossible to palpate unless they are enlarged or mineralized. Turtles and tortoises usually present the biggest challenge when trying to perform a complete physical examination. The shell makes it difficult to palpate most of the organs. Depending of the size of the animal, one or two fingers may be placed in the inguinal area between the hind limbs and the shell. This will enable you to palpate the coelomic cavity for any abnormalities such as cystic calculi, foreign bodies, neoplasia, or potentially eggs. It is also important to make note of the shell quality and color (or skin quality and color in lizards and snakes). If the animal has a systemic infection or is septic, petechiae and ecchymosis can often be found on the shell, especially the plastron. Petechiae and ecchymosis are also seen in other reptiles when a systemic infection or septicemia is present. In snakes, petechiae and ecchymosis are often seen on the ventral aspect of the animal, while in some lizards such as iguanas; petechiae and ecchymosis are commonly seen on the dorsal spines along the animal's back.
During the physical exam, make sure to get an accurate heart rate and respiratory rate. A heart rate is most easily obtained by using a Doppler®,. Most of our reptile patients cannot be auscultated with a stethoscope so a Doppler® is an essential tool to have in your practice. In lizards, the Doppler® probe should generally be placed in the same area a stethoscope would be placed on a dog or cat. In a few species such as monitor lizards, the heart is found much more caudal then one would expect. You will need to place the probe on the very caudal aspect of the thoracic cavity. In snakes, the Doppler® probe will need to be placed on the ventral surface of the cranial 1/3 of the body. In chelonians, the Doppler®, probe is either placed into the thoracic inlet (on either the left or right side) or on the neck over the carotid artery. Both the heart and respiratory rates are obtained by simply counting the number of beats and breaths per minute.
Normal physiological values
Generally, normal physiological values in reptiles have an extremely large range. Many reptiles can have a heart rate that ranges from approximately 10 beats per minute to about 80+ beats per minute. Heart rates and respiratory rates can vary depending on ambient temperature, age, species, and health status. The respiratory rate may range from just a few breaths per minute to 20 or more breaths per minute depending on the previously mentioned factors. The body weight of your patients will also vary depending on age, sometimes sex, nutritional status, and the species you are working with. Patients can range from as little as a few grams to several kilograms. Body condition scoring is also performed on reptiles and follows the same guidelines that are used in mammalian medicine. The scale ranges from 1-9 with 1 being emaciated and 9 being grossly obese. Landmarks used to score a reptile's body may include palpability of the ribs and pectoral/pelvic girdles as well as the girth of the tail.
Lizard venipuncture sites
The cephalic, jugular, and ventral abdominal vessels can be used to obtain a blood sample from various species of lizards you may encounter in your clinic. However, these vessels are not commonly used for several reasons. The cephalic vein is usually extremely small and because this is a "blind stick," a surgical cut down may be necessary. The ventral abdominal vein is not generally used (especially in awake animals) due to the inability to both properly restrain the animal and control hemorrhage. Lastly, the jugular vein is not commonly used because in many species it is also a "blind stick" and may also require a surgical cut down to access the vessel. Lymphatic fluid contamination is also common when performing venipuncture from the jugular vein. Lymphatic fluid contamination can skew your blood values.
The most common vessel used for lizard venipuncture is the caudal tail vein, also called the ventral coccygeal vein. There are two different techniques commonly used to obtain blood from this vessel. These techniques include a lateral and ventral approach. To successfully obtain a blood sample from either approach, a 1" or 1 ½" 27 to 20 gauge needle attached to a 1ml or 3ml syringe should generally be used. The size of the needle and syringe will depend on the size lizard you are drawing blood from. Insulin syringes can be used on very small lizards, but remember to cut the needle off before putting the blood into the appropriate tubes. The small needle size can cause lysis of the blood cells if pushed through the needle (the same is true for 26 or 25 gauge needles). It is important that the tail is gently restrained during the blood draw. The left hand can be used to restrain the caudal portion of the tail, while the right hand can be used to perform the blood draw. If you are left handed, just obtain your blood sample from the other side of the tail using your left hand to draw blood and your right hand to gently restrain the tail.
For a lateral approach, the needle should be inserted into the tail (between two scales) at approximately a 90° angle. Slowly insert the needle into the tail, keeping slight negative pressure on the syringe until either blood enters the syringe or the needle touches the vertebrae. If the needle is touching the vertebrae, slowly back the needle off the bone (still keeping slight negative pressure on the syringe) and redirect the needle into the vessel. It is important to put only slight negative pressure on the syringe while obtaining the blood sample. Too much negative pressure may collapse the vessel.
The technique for the ventral midline approach is very similar to the lateral approach. The needle should be inserted on midline into the tail (between two scales) at approximately a 90° angle. The needle should be slowly inserted into the tail, keeping slight negative pressure on the syringe until either blood enters the syringe or the needle touches the vertebrae. The blood vessel is located just ventral to the vertebrae. If you touch the vertebrae first, slowly back off of the bone until your needle is seated within the vessel.
Lizards usually struggle when they are placed on their backs, making it difficult to draw blood from them. Therefore, it is important to keep the animal in sternal recumbency while obtaining the blood sample.
Chelonian venipuncture sites
The brachial plexus, subcarapacial venous sinus, and jugular vein are the major sites where blood can be obtained from a turtle or tortoise. The venipuncture site will depend on the size and species of the patient and the preference of the phlebotomist. If drawing blood from the jugular vein, the turtle/tortoise should be placed in lateral recumbency. The head and neck should be pulled away from the shell. The jugular vein can be found in the same plane as the eye and the tympanum. To obtain the sample, the phlebotomist will hold the head while the restrainer will keep the patient in lateral recumbency. A 27 to 20 gauge needle attached to a 1 to 3 cc syringe is generally used and will vary depending on the size of the patient. The subcarapacial venous sinus is generally used when jugular venipuncture is not an option. Depending on the size of the patient, a 1" to 1 ½" 27 to 20 gauge needle or a 2" spinal needle attached to a 1 to 3 cc syringe is used to obtain the blood sample. The needle is inserted upward at about a 60-degree angle just dorsal to the neck. Slight negative pressure should be applied on the syringe until either blood enters the syringe or bone is encountered. If bone is encountered, back away from the bone and redirect the needle. The brachial plexus, also called the ulnar venous plexus can only been used in most chelonians. Pull the front limb away from the body and palpate the tendon near the radiohumeral joint. Generally, a 22 to 20 gauge needle attached to a 1 to 3 cc syringe is inserted at a 90-degree angle to skin and angled towards the radiohumeral joint. The tail vein can also be used in chelonians. The same technique used in lizards can also be applied to chelonian species.
Snake venipuncture sites
The two venipuncture sites in snakes include the caudal tail vein and the heart. Drawing blood from the tail vein is best accomplished in large snakes as it can be difficult in small snakes due to the size of the vessel. The same method used to draw blood from the ventral midline approach in lizards is used in snakes as well. Obtaining a blood sample from the heart (also called cardiocentesis) is generally the quickest method which will yield a large amount of blood. A 27 to 22 gauge needle attached to a 1 or 3 cc syringe is used for blood collection (size of needles and syringes will depend on the size of the snake). To obtain a blood sample, the snake should first be placed in dorsal recumbency. The heart can then be located in the cranial 1/3 of the body. The heart can move both cranially and caudally so it is best to place your thumb and index finger on either side of the heart. Look for the caudal portion of the beating heart. The needle insertion site should be two scutes (scales) below that. To obtain blood, the needle should be inserted between two scutes at a 45-degree angle. It is important to not poke around searching for the heart. Insert the needle in one fluid motion. Place slight negative pressure on the syringe and let the beating of the heart slowly fill the syringe. The palatine vessels can be used in some instances, but this technique is not suggested as it is difficult to provide hemostasis, the vessels are very small, and the mouth is filled with bacteria.