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Physical Restraint Techniques and Immobilization Equipment
ANALGESIA AND ANESTHESIA
1094-9194/ 01 $15.00
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PHYSICAL RESTRAINT TECHNIQUES AND IMMOBILIZATION EQUIPMENT Mitchell Bush, DVM
The safe and effective use of physical restraint is an art form that is perfected by continual learning. With the development of safer anesthetic protocols, the use of physical restraint is becoming a lost art but is still appropriate in many management and medical procedures. This article provides an overview of the equipment and techniques for physical restraint of nondomestic species that are seen and treated by practitioners. PHYSICAL RESTRAINT
The scope of this article does not allow an extensive review of physical restraint techniques for captive nondomestic species, a subject extensively reviewed elsewhere.4 Physical restraint by its nature affects the patient in various physical, physiologic, and psychological ways. The physical aspect relates to injuries incurred from the procedure that range from muscle strains to life-threatening trauma. The physiologic changes are grouped under the broad heading of Stress, which can be minor or life threatening. It is difficult to obtain a consensus on how stress and psychological changes can be monitored, but they do occur. The platinum standard for a successful restraint is to use the minimal amount needed to accomplish the procedure safely and properly with the well being of the patient being of paramount importance. Currently,
From the Conservation and Research Center, Smithsonian National Zoological Park, Front Royal, Virginia
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it is safer and more humane to anesthetize than to physically restrain patients for major manipulative procedures. Physical restraint can also be an important component to an anesthesia procedure, especially when the proper and timely use of physical restraint can preclude the use of additional anesthetic agents. Several factors contribute to a successful restraint procedure, including the type and temperament of the patient, the equipment, and the experience of the handler(s). The type of restraint procedure used depends on whether the patient is located in a clinic or is treated at the facility where it resides. In a clinic there is usually better control of the procedure because of access to appropriate equipment and trained staff. When a nondomestic patient is treated at its residence, the type of restraint procedure used is governed by the onsite facilities and staff. Before a physical restraint procedure is begun, an evaluation of the procedure and patient is necessary: 1. Can the planned procedure be done with physical restraint only? 2. Will the procedure cause patient pain? If so, general anesthesia should be used. 3. Can the procedure be performed safely for the animal and staff? 4. Are the appropriate facilities, equipment, and staff available? 5. What are the patient's defensive weapons and how are the handlers protected? 6. How can the animal's flight distance be minimized to facilitate safe capture?
Perhaps the hardest thing to do is to back off from a manipulative procedure, whether it involves physical restraint or anesthesia. Many procedures require extensive coordination to be performed successfully. · Unless one is conducting an emergency procedure, if things are not proceeding according to plan, or if there is a factor that can be changed to enhance success, the procedure should be stopped and rescheduled. BASIC RESTRAINT EQUIPMENT
If a practice sees, or hopes to see, nondomestic patients, it should obtain basic restraint equipment (Table 1). The equipment required depends on the type and size of the patients seen. The following discussion is about basic equipment and its function and is not complete. The size of the equipment is patient dependent, but most of the equipment discussed can be used on a wide range and size of species. Hoop nets are a basic tool used to capture and restrain a wide variety of species, from small birds to mammals weighing up to about 20 kg. Nets are constructed of mesh or a sack, depending on the species and user preference. Nets vary in sizes and types, but the basic functional net is deep enough so when the animal is captured the net can either be twisted or flipped on itself to properly control the animal prior to its removal from the net. Newer nets with plastic rims may not be
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Table 1. BASIC EQUIPMENT AND TECHNIQUES APPLICABLE FOR RESTRAINT OR IMMOBILIZATION OF VARIOUS NONDOMESTIC SPECIES Patient
Net
Snare
Small Mammal Medium Mammal Hoofstock Primates Birds Reptiles
+ +
+
Plastic Tube
Gloves or Towel
+
+ ±
±
+ + ±
±
+
±
+
+ ±
Shield
Remote Injection
+ + + +
±
±
+ + +
+
±
Squeeze Cage
±
+
+
rigid enough to prevent the escape of some larger animals that lift the plastic rim (especially primates). Confined animals can be netted if a slow, purposeful movement is made, allowing the net to be placed over a stationary animal. The proper use of the net for capturing a moving animal is to anticipate where the animal will go and place the net in its path so that it enters the open net. Attempt to swing the net at the animals has two results; first, the animal probably escapes, or second, it can be hit and possibly injured by the net's rim. As with all equipment, nets become damaged and develop holes where animals have chewed through the mesh. All nets, therefore, should be checked prior to use. Nets and other capture equipment can become contaminated and act as fomites; therefore, they should be properly sanitized between patients. Protective gloves are commonly used to protect the handler from claws, talons, and teeth during capture and restraint. The glove's thickness should be appropriate to the patient, but many of the larger carnivores are capable of biting through most gloves or crushing fingers without damaging the gloves. In certain situations, the glove, without the fingers inserted, is presented for the animal to grasp and hold while capture is made using the other hand. Problems with the heavier gloves are the handler loses dexterity and has a tendency to apply too much pressure during the procedure, which can compromise the patient's respiration or cause other trauma. Gloves are also fomites and are difficult to sanitize properly between patients. A heavy towel is a versatile capture and restraint tool providing a visual shield and some protection against teeth and claws. The towel can be used in combination with gloves, if preferred. The towel is used to distract the patient and limit its field of vision during capture. Preferably, it is dropped over the patient to contain it prior to capture. The towel has the benefits of covering the animal's head and giving it something to grasp, both of which help to calm some animals. Although towels are fomites, they can be washed and sanitized after each use. Clear plastic tubes are useful tools for restraint and short transport procedures in small mammals and reptiles (Fig. 1). Various tube diameters should be available, because the proper tube size is about 10% to 15% larger than the patient's diameter, to allow some movement but to prevent the animal from turning around. The ends of the tubes can be plugged with towels or appropriate material to adjust the length of the
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Figure 1. A clear plastic tube is used to restrain a Black Footed Ferret for closer examination, and can also be used as an anesthesia chamber. (Courtesy of Lisa Ware, Conservation and Research Center, Smithsonian National Zoological Park, Front Royal, Virginia.)
chamber. A tube with slits or holes allows some access to the animal. Plastic tubes are also excellent chambers for induction with inhalant anesthetics. These tubes can be easily cleaned between patients to prevent the spread of disease. Handheld shields are useful restraint devices that also protect the handler. In smaller mammals, a clear Plexiglas shield with a handle is used to compress the animal to the rear of a cage. A shield with holes allows injections to be given (Fig. 2). Clear shields are useful for capturing some reptiles. Larger shields or crowding boards are used with hoofstock and are usually opaque, to obliterate the human shape. These boards are equipped with handles and should have a viewing port so that the operator can see and respond to the animal (Fig. 3). The shield is used to move or shift the animal or to allow a protected approach to the animal for observation or injection by a pole syringe. Snares are used to gain control of the animal's head for capture. These devices have been called Rabies poles or catch poles and are available commercially or can be constructed. When catching most mammals, catch the neck and one foreleg to preclude excessive tracheal pressure as the snare is tightened or if the animal struggles. A major problem can occur when the animal is snared only by the neck and if it starts to roll the noose begins to twist and tighten around the neck. When this occurs, the quick release does not work and as the animal continues to roll, the tighter the noose becomes. Squeeze cages are indicated if a moderate volume of nondomestic species is seen because they facilitate observation and treatment. The basic squeeze cage contains a movable wall that compresses the patient
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Figure 2. A clear plastic shield is used to confine a patient for closer examination or possible injection through the holes in the plastic. (Courtesy of Lisa Ware.)
to the opposite wall of the cage (Fig. 4). The walls are bars so that observations and injections are possible on the restrained animal, but the spacing of the bars can allow some patients to strike out at handlers. These cages can vary in size for small mammals up to the size that will handle large carnivores (tiger or bear). These larger cages usually require some type of mechanical advantage for the operator to compress the animal. Animals can be housed in these cages during treatment periods or shifted into them for treatment.
METHODS AND EQUIPMENT FOR DRUG ADMINISTRATION
Drug injection is central to many medical procedures, including medication, vaccination, and anesthesia. The method of drug delivery depends on drug volume and viscosity, type of patient, access to the patient, available equipment, and ability of the operator.
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Figure 3. A plywood crowding board is used to move this female Eld's Deer. Note the plastic view area in the crowding board. (Courtesy of Lisa Ware.)
Figure 4. A squeeze cage for restraint of small- to medium-size animals. The hand crank on the front of the cage moves the rear wall forward.
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Intramuscular Injections
When rapid absorption is desired, inject into the muscle mass because of the plentiful blood supply. The major muscle masses of the shoulder or the legs are preferred. Injections given subcutaneously (SC) in the neck or over the back are usually less desirable if rapid adsorption is required, because of a reduced blood supply. The hand syringe is the method of choice because it allows accurate and complete drug delivery when the patient is restrained properly. The tendency is to give the injection rapidly, but, if possible, the delivery should be slow to minimize pain associated with rapid stretching of muscles and nerves from the fluid infusion. Semiremote intramuscular (IM) injections are given using a pole syringe (Figs. 5 and 6). The pole acts as an extension of the syringe's plunger. The length of this extension pole can vary from a foot or two up to several feet, but with increasing length, there is added weight, decreased mobility, and less accuracy. The syringe is covered with a sleeve to guard against needle breakage and to prevent syringe breakage where the needle attaches. Pole syringes are commercially available or can be constructed rather easily. A dark-colored pole syringe slightly decreases the chance of its being seen by the patient. The drug injection begins on impact, and contact with pressure must be maintained with the animal for the duration of the injection. For small volumes (1 mL3 mL) this is not a problem, but for larger volumes of 6 mL to 12 mL, the contact and pressure must be maintained for 1 to 2 seconds. Contact
Figure 5. Three pole syringes, which can be used for injections at a distance. The top pole is a 3 ml capacity syringe, which is empty. The middle 6 ml syringe pole has been loaded with 3.5 ml of drug. The bottom 12 ml syringe pole has a needle guard over the needle to prevent breakage of the needle and/or hub of the needle. Note piece of tape holding the needle guard in place. (Courtesy of Lisa Ware.)
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Figure 6. The use of a 3 ml pole syringe to inject a female Eld's Deer. (Courtesy of Lisa Ware.)
time can be decreased by using large-gauge needles (14- or 16-gauge), but these tend to lacerate the moving animal during an injection. Most patients soon learn to recognize the pole syringe and present a moving target. In these cases, an attempt first to confine the patient is made, the patient's movements are anticipated, and the pole follows the animal's direction during the injection thrust. The use of the dart gun at first seems to be the answer to all problems associated with remote delivery of drugs in uncooperative nondomestic species, but each darting system has certain disadvantages that should be understood. The use of any remote darting equipment requires the precaution and judgment mandatory when handling any firearm. The proper use of the projectile syringe requires marksmanship and practice, first on inert targets to understand the gun's sighting and how to minimize dart impact. Other variables to be considered with each shot include target distance and how to compensate by aiming or adjusting the propellant force of the delivery system. Second, the size and weight of the dart determines the propellant force necessary to hit the target. Wind currents particularly influence large darts that are . projected for long distances. For a historical review of remote delivery devices, the reader is referred elsewhere. 1 Historically, the explosive projectile darts for IM injections were the standard method for remote drug delivery to large mammals. The primary dangers of these systems when used improperly were high-energy body impact, causing extensive muscle damage, fracture, or body cavity penetration. The current delivery systems use less
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traumatic, lightweight plastic darts (Fig. 7). These darts have several basic components: 1. The needle's hole is on the side (not the end) and a moveable
sleeve covers it. 2. The syringe barrel (1 mL-10 mL) contains a moveable plunger anterior to a sealed compartment. 3. The dart contains a tailpiece to facilitate aerodynamic flight. The drug is placed in the syringe barrel in front of the movable plunger, and the needle is attached. The moveable sleeve covers the hole on the side of the needle. The chamber behind the moveable plunger is pressurized with air or liquid butane, placing a compressed force on the drug compartment. The dart is placed in a delivery device, which can be either a blowpipe (using lung pressure) or COrpressured injection devices. When the dart's needle penetrates the skin, the sleeve is pushed posteriorly, uncovering the hole and allowing the pressurized drug to be injected as the plunger is forced forward. Some patients do not even realize that an injection has occurred. The delivery range varies with the propelling system; using lungpower, a dart can be delivered accurately up to 10 to 15 meters; other systems using compressed air or a powdercharged rifle allow effective ranges of 40 to 60 meters. When butane is the pressurizing agent, cold temperatures can inhibit butane's expansion characteristics, preventing complete drug injection and thereby limiting the effectiveness of this delivery system.
B
Figure 7. A diagram of an air pressurized plastic dart. 1 = drug chamber; 2 = pressurization chamber; 3 = one-way valve. A, Pressurized dart in flight. B, Dart in final stage of injection. (From Bush, M: Remote drug delivery systems. J Zoo and Wildl Med 23:159-180, 1992; with permission.)
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CAPTURE AND CONTROL
Basically, physical restraint has two phases, first capture and then control of the patient. The actual physical capture has several stages, all of which can be assisted by planning, experience, and equipment. It is desirable to capture the animal from a small enclosure or crate, which allows the operator good vision and room to orchestrate the capture. The animal should be captured in a timely manner, with minimal excitement and trauma, using controlled, purposeful movements and limited noise. These ideal criteria are not always achievable goals, however. The control phase of the restraint procedure depends on the species and the procedure to be performed. Basic guidelines for this phase are that the restraint is firm with total control that is not excessive or traumatic, but this balance can be a difficult to achieve without extensive experience. In smaller patients, when heavy gloves or nets are used, care is taken to monitor any respiratory compromise. Covering the eyes helps calm some species during a restraint procedure. Talking, extraneous noise, and unnecessary patient movement should be avoided to limit stimulation of the patient. Nondomestic patients seen in practice situation which require manipulative procedures can be categorized as follows: 1. Small mammals (<5 kg) 2. Medium-sized mammals (5 kg-10 kg) 3. Small to medium hoofstock (:s:400 kg) 4. Primates 5. Birds 6. Reptiles Small Mammals
This section does not include the "pocket pets" (i.e., ferrets, hamsters, chinchilla, mice, or hedgehogs) which are restrained in a manner similar to domestic dogs and cats. Usually, these patients are accustomed to handling and pose no unique problems. On small nondomestic mammals of 5 kg or less, minor manipulative procedures previously were accomplished using physical restraint by means of gloves or nets. Physical restraint still can be the method of choice for minor short procedures that entail minimally painful stimuli (i.e., vaccinations, ear tagging, nail trims). Any extensive procedure or surgical manipulation requires general anesthesia. The use of clear plastic tubes offers a simple way to confine a small patient for better observation and control. The animal is directed from a nest box, net, crate, or from a hand capture into a tube about 10% to 15% larger than the patient's diameter. Initially, the tube can be covered with a towel to let the tube appear as a dark hiding place. The tube can be plugged with a towel at each end. Once the animal is in the tube, close observation is possible. The tube also can be used as an anesthetic chamber for induction with inhalant anesthetics.
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Plastic shields restrain and confine caged small mammals for closer observation or administration of injection. The shield restricts the patient's space by pushing it up against the wall of a cage. The shield should be clear and have a handle for the operator to use while applying pressure to the animal. The size of the shield should be slightly smaller than the dimensions of the cage it is used in. It is helpful to have several slits or holes in the shield to allow injections of medications or anesthetics. Many small mammals are presented in small kennels, and the challenge is to remove them from their crates and proceed with the restraint. There are several approaches to this situation. A net can be inserted and the animal netted prior to removal, but this can be a problem (e.g., the opening of the kennel is usually smaller than the size of the desired net). In some patients, a heavy towel is used to limit the animal's view while it is pressed against the far wall and grasped. It is usually difficult to get the animal transferred to a squeeze cage because the animal prefers to stay in the kennel. One could have the client build a movable wall in the back of the kennel that could be used to force the patient to the front of the cage into a squeeze cage, net, or plastic tube. As a last resort, a snare pole can be used to secure and remove the patient. Medium-sized Mammals
These animals are the upper limit that can be managed with nets or gloves; therefore, the use of a squeeze cage is recommended. A squeeze cage facilitates minor procedures on medium-sized to large mammals by allowing close visual examination, administration of medication, and injection of anesthetic by hand syringe. HOOFSTOCK
This diversified group of mammals varies markedly in temperament and physiology, which dictates the need for various handling strategies. This section discusses cervids and bovids up to 400 kg. Generally, loading and routine management movement of hoofstock can be accomplished without anesthesia. Adequate runways, chutes, and crates are required to facilitate animal separation, shifting, and confinement. Conditioning and the animal's familiarity with the facility allow nonstressful crating for shipment or for a medical procedure. 8 The greatest chance of success occurs if the following criteria are met: 1. The facility's restraint location is accessible to the animals by
runways from other enclosures. 2. The runways and gates allow movement and separation of animals by remote controls. 3. The floors provide sure footing, allow drainage, and can be readily sanitized.
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4. The walls are solid, smooth, and sufficiently tall to discourage the animal's attempt to climb or jump. 5. Observation ports are available to monitor the animal's position and condition during the procedure. 6. The design permits forcing the animal into a more confined area and eventually into a crate, squeeze chute, or trailer. Physical restraint of small hoofstock (<15 kg) is appropriate for minor procedures (i.e., bleeding, worming, medicating). The major risk is not the physical holding of the animal, but rather initial capture in the enclosure or cage. Nets are useful, but there is a chance of injury from improper use, which can entangle a leg. The rigid net hoop can also cause trauma. In addition to confinement in a standard cage or catchpen, 10 an animal can be confined into a corner with handheld wooden shields (crowding boards) or with a curtain of an opaque material (e.g., plastic sheeting). The use of crowding boards or a curtain protects the staff, obscures the outline of the human form, and decreases the flight distance, while reducing excitement. Actually grabbing an animal requires skill as well as knowledge of the animal's potential for injuring itself or the handler. The sharp hooves and powerful rear legs of small hoofstock are capable of cutting through clothes and skin. The sharp horns of small-sized antelope, and, in some species, teeth (i.e., muntjacs, Muntiacus sp.) can cause severe punctures or lacerations of the handler. Once caught, the animal's body is wrapped around the handler's hip, so that the powerful back muscles are misaligned, thereby minimizing effective kicking. Grasping the horns or antlers offers a good method of controlling the animal's head and movements. Caution is needed when handling cervids with developing antlers (in velvet) as they can abrade and fracture easily, with extensive bleeding and resultant malformation of the mature antler. Similar precautions are needed when grasping the horns of immature bovid because these are loosely attached and can be permanently damaged. Physical restraint of larger-sized hoofstock requires a shield, chute, or squeeze cage. Bovids usually tolerate more physical restraint and manipulation than do cervids. Some medium-sized antelope can be slowly crowded into a corner. They can then be made to lie down, allowing minor procedures to be performed. This judgment comes with knowing the animal and being able to read its reactions. For handling larger species of bovids or cervids, some modified commercial cattle chute with covered top and smooth, solid sides is one option for minimizing injuries during struggling. Once the animal is secured, side boards on the chute can be removed to gain access to the animal. The head catch of commercial chutes is dangerous because some animals tend to twist or spin once the head is secured, a potentially fatal maneuver. Physical restraint in excitable hoofstock can result in capture myopathy.7· 9 In many situations, anesthesia involves less risk to the patient and the handlers. In most facilities that routinely physically handle larger hoofstock, a drop-floor chute or a hydraulic squeeze chute is preferred. Both devices apply lateral compression and position the animal's feet
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off the ground to help preclude struggling. Having better access to the animal and the increased safety to animal and handler can offset the initial cost and result in significant cost savings from repeated use of anesthetic drugs. Primates
Primates increasingly are not being kept as pets and therefore are not being seen by practitioners. In rare circumstances when minor nonpainful manipulations are performed, physical restraint could be used for smaller primates (<2 kg). Primates are strong, fast, and can inflict severe bite wounds. To facilitate safe capture and restraint, nets and gloves are commonly used. The recent concerns about herpes B virus has all but stopped any physical restraint procedures on macaques (Macaca sp.) which are carriers of the virus. All procedures should be performed on macaques that have been anesthetized using dissociative anesthetics. Most other primates can harbor potential zoonotic diseases, and appropriate safeguards are recommended, in addition to owner counseling. A squeeze cage is indicated for procedures on medium-sized to large primates because it allows visual examination, administration of medication, and injection of anesthetic by hand syringe. AVIAN SPECIES
This group covers a wide range of species and sizes, ranging from small finches to ostriches. This section groups birds into five groups: (1) small caged birds, (2) psittacines, (3) raptors, (4) cranes, and (5) ratites. Small caged birds are many times the most difficult to capture and restrain physically because of the associated problems of stress. Capture is facilitated if the bird is alone in a small cage with subdued light. Small nets are placed in the expected flight path of the bird for capture. Once netted, the bird is carefully removed, taking care not to injure legs, wings, or toes. The head is supported between the thumb and forefinger with the body of the bird, with the wings folded, lightly encircled by the hand. Once secured in this position, the legs and wings can be extended carefully for examination or treatment. The bird is released so that it does not wildly fly off and hit the cage wall or ceiling. Psittacines, especially the larger parrots, are strong birds and can inflict severe wounds with their bills. The first goal is to control the head and beak with one hand, while the wings are wrapped to prevent flapping and injury. The legs are grasped with the other hand. Initial capture is usually done with a net or a very heavy towel placed over the bird's head. A clear plastic shield can be use to crowd a parrot to the back of a cage before the head is grasped. The larger parrots are not for the novice because they can produce severe bite wounds. The restrained bird is usually very vocal; this should be anticipated and the head covered to help calm the bird.
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When restraining raptors, take care to avoid the talons, which can inflict major painful wounds. The beak is also capable of creating a nasty wound. The initial capture usually is done with a net; the talons must be secured first, then the beak, before the bird is removed from the net carefully so as not to entangle it and cause injury. Placing a hood over the head to cover its eyes can help to calm the bird and facilitate the procedure; if the head must be examined, it is best to leave the bird hooded for a few minutes then remove the hood slowly for the exam. Heavy gloves and towels can be used as an alternative for a net for capturing raptors that are on the ground or in a cage. Ideally, the bird should be approached from above and behind, and the towel is used as a shield. The bird is then wrapped in the towel, taking care again to secure the talons and beak before proceeding with removing the bird from the towel. With some calmer raptors on a perch in a small cage, it is possible to use a newspaper to shield the bird's vision as one grasps both legs with a gloved hand. One must gain control of both legs with this procedure. This technique requires some practice and coordination and is best practiced on smaller raptors first, but once mastered, it is a rapid and less stressful method of capture. Cranes can be encountered as wild birds or from an aviculturist. They present some unique physical restraint challenges. Cranes are large birds with powerful wings and legs and a pointed bill, all which can be used as weapons. It is recommended that eye protection be used when handling them. The nails are capable of causing painful dirty wounds in addition to the pounding and bruising from their strong wings. The best capture method is usually to herd them into a comer and grasp the wings from behind, putting some downward pressure on the back to prevent the bird from kicking out with the legs and cutting the handler or themselves with their sharp nails. Once the crane is secured, the head is controlled and the bird is lifted with the body held under one arm, with its wings folded. The feet are held out in front of the handler and the head and neck extended behind. It is best not to fold the bird's legs when holding them, especially if the restraint is to be prolonged, because this can lead to muscle stiffness. If the bird is very aggressive, a second person is sometimes required to hold the head and neck. Hooding a crane is indicated to calm the bird. Both legs should be held together with a finger separating them to avoid their scraping against each other. Releasing the bird must be done with care to avoid injury. Again, one must watch for the bill while placing the bird's feet on the ground. Exert downward pressure on the legs so that the bird does not kick or rake itself as it is released. Ratites
Ostriches and emus have become popular in some areas and are raised as a commercial venture. Adult ratites are difficult to restrain physically because of their great strength and size. They are capable of causing major injury to themselves or handlers. Birds of 3 to 4 feet tall
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are the largest that can be restrained safely. The key is to approach the bird from behind to avoid being kicked. Restrain the bird by grasping the rudimentary wings to gain control. Once this is done, grasp both legs and assist the bird to lateral recumbency, with the legs held extended posteriorly. Hooding these birds is indicated to reduce stress. Larger ratites can be herded into confined areas by using a crowding board, but their kick can break such boards. Once the bird is in a confined area, closer examination is possible, and injections with a pole syringe can be done. REPTILES
Reptiles include a wide variety of species that require different handling strategies. Probably the most common reptile presented to the practitioner is a snake. (This discussion does not include the handling of venomous species.) Most snakes kept as pets are usually handled by the owner; this allows a fairly detailed physical examination and medication administration. When handling any snake, be aware that Salmonella spp. is a common bacteria found in most reptiles and poses a possible zoonotic problem. Even the calmest snake can bite, and they usually break off teeth, which can act as a foreign body in an infected wound. To transport snakes, a soft cotton bag is recommended. When the snake is to be captured, the bag can be collapsed on the snake and provides a shield and some padding when the handler pins and extracts the snake from the bag. Plastic tubes are also an excellent way to restrain and examine the snake. The diameter of the tube should be about 20% larger than the snake's diameter to prevent the animal from getting stuck, while preventing it from turning on itself. The snake can be enticed or placed in the tube. For some procedures, after the snake is partially in the tube, the snake and the tube are grasped together to secure both the snake and the tube. This leaves a portion of the snake exposed, and the snake also can be repositioned for exam or treatment of other areas. The tube can be used as an induction chamber for inhalant anesthesia. The classic method of catching and restraining snakes has been the use of a snake hook or tongs and when used by an experienced herpetologist-these are useful tools. When used inappropriately, they can cause injury to the snake. Two mistakes often made with a snake hook are applying too much pressure just behind the head when the snake is pinned (which can be minimized if a foam pad is placed under the snake's head prior to pinning it) and dangling a large snake by the hook, which applies too much point pressure to the animal's spine, which predisposes it to injury. Padded tongs are an acceptable method of capturing a snake so that it can be grasped behind the head, but again, care must be taken to avoid unnecessary pressure. The snake hook and tongs can be used to direct a snake into a tube or a bag for further restraint or capture. A plastic shield is useful to pin a snake to
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the bottom of a box to assist in the capture. After capture, the snake's head is grasped with the thumb and forefinger for control. When holding a snake, always support the body when lifting or carrying it, to prevent spinal injury. Many snakes will wrap around the holder 's arm, which supports the weight, but this method can be a problem in large constrictors, which should be handled only when enough experienced people are present (about one person per 1 meter of snakelength). When capturing and restraining lizards and monitors, the handler should be aware of the two defensive weapons they have: the mouth, which contains sharp teeth, and the tail, which can lash out and strike the handler, also potentially damaging the animal's tail. The object is to grasp the head and block the tail from flaying as it is grasped. Plastic shields are useful in controlling or pinning the animal prior to grasping. Following initial capture, the animals can be placed in a plastic tube for further examination, transport, or induction of gaseous anesthesia.
CROCODILIANS
Physical restraint is practical for animals up to 1 meter. The crocodilian' s weapons include the mouth and tail. Keeping the mouth securely closed is the best method of control. For the initial capture, a snare pole can be used to grab the mouth, keep it closed until the animal's mouth is better controlled with both hands or by taping the mouth shut. After the mouth is controlled, attention can be shifted to the tail, which can lash out and injure the handler. With the head and mouth secured by a snare pole, the pole is then aligned with the animal's body and the tail is grasped and stabilized against the pole.
References 1. Bush M: Remote drug delivery systems. J Zoo Wild! Med 23:159-180, 1992 2. Bush M, Custer R, Smeller JM et al: Physiologic measures of nonhuman primates during physical restraint and chem ical immobilization . J Am Vet Med Assoc 171:866-869, 1977 3. Chalmers GA, Barrett MW: Capture m yopathy. In H off GL, Davis JW (ed s): Noninfectious Diseases of Wildlife. Ames, Iowa State University Press, 1982, pp 84-94 4. Fowler ME: Restraint and H andling of Wild and Domestic Animals. Ames, Iowa State University Press, 1978 5. Harthoorn AM: The drug immobilization of large herbivores other than antelope. In E. Young (ed): The Capture and Care of Wild Animals. Cape Town, South Africa, Hum an and Rousseau , 1975, p 52 6. Harthoorn AM: Restraint of undomesticated anim als. J Am Vet Med Assoc 149:875880, 1966 7. Harthoorn AM, VanderWalt K: Physiological aspects of forced exercise in w ild ungulates with special reference to (so-called) overstraining disease, 1. Acid-base balance and PO levels in blesbok (Damaliscus dorcas phillipsi). J South Afr Wild! Mgmt Assoc 103:64-68, 1974 8. Harthoorn AM: The u se of corrals to capture and train wild ungulates prior to relocation. Vet Rec 104:349, 1979
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9. Hofmeyr JW, Louw-GN, de Preez JS: Incipient capture myopathy as revealed by blood chemistry of chased zebras. Madoqua 7:45-50, 1973 10. Jones DM Physical and chemical methods of capturing deer. Vet Rec 114:109-112, 1984 11. Wiesner H: Tranquilization by the blowgun rifle method. Kleintierpraxis 22:327-330, 1977
Address reprint requests to Mitchell Bush, DVM Conservation and Research Center Smithsonian Institution 1500 Remount Road Front Royal, VA 22630 e-mail: [email protected]
APPENDIX
Sources of Equipment Remote Injections Pole Syringe Zoolu Arms of Omaha 10315 Wright St. Omaha, NE 68124 (805) 397-4983
Dart Gun (Daniject) Wildlife Pharmaceuticals 1401 Duff Drive Ft. Collins, CO 80524 (303) 484-6267
Nets/Snares/Snake Hooks Fuhrman Diversified 2912 Bayport Blvd. Seabrook, TX 77586-1501 (281) 474-1388
Nets Memphis Net & Twine Con, Inc. 2481 Matthews Ave. P.O. Box 80331 Memphis, TN 38108 (901) 458-2656
Animal Care Equipment and Services, Inc. P.O. Box 3275 Crestline, CA 92325 (800) 338-ACES
Hoofstock Chutes Fauna Research, Inc. 8 Bard Ave. Red Hook, NY 12571 (914) 758-2549
Reptile Equipment Midwest Custom Products, Inc. 14505 S. Harris Rd. Greenwood, MO 64034 (816) 537-4444
Other Related Equipment Nasco 901 Janesville Ave. Fort Atkinson, WI 53538 (920) 568-5600
Squeeze Cages Bryan Research Equip. 400 Stone City Drive Bryan, TX 77801 (409) 778-3100
1094-9194/ 01 $15.00
+ .00
PHYSICAL RESTRAINT TECHNIQUES AND IMMOBILIZATION EQUIPMENT Mitchell Bush, DVM
The safe and effective use of physical restraint is an art form that is perfected by continual learning. With the development of safer anesthetic protocols, the use of physical restraint is becoming a lost art but is still appropriate in many management and medical procedures. This article provides an overview of the equipment and techniques for physical restraint of nondomestic species that are seen and treated by practitioners. PHYSICAL RESTRAINT
The scope of this article does not allow an extensive review of physical restraint techniques for captive nondomestic species, a subject extensively reviewed elsewhere.4 Physical restraint by its nature affects the patient in various physical, physiologic, and psychological ways. The physical aspect relates to injuries incurred from the procedure that range from muscle strains to life-threatening trauma. The physiologic changes are grouped under the broad heading of Stress, which can be minor or life threatening. It is difficult to obtain a consensus on how stress and psychological changes can be monitored, but they do occur. The platinum standard for a successful restraint is to use the minimal amount needed to accomplish the procedure safely and properly with the well being of the patient being of paramount importance. Currently,
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it is safer and more humane to anesthetize than to physically restrain patients for major manipulative procedures. Physical restraint can also be an important component to an anesthesia procedure, especially when the proper and timely use of physical restraint can preclude the use of additional anesthetic agents. Several factors contribute to a successful restraint procedure, including the type and temperament of the patient, the equipment, and the experience of the handler(s). The type of restraint procedure used depends on whether the patient is located in a clinic or is treated at the facility where it resides. In a clinic there is usually better control of the procedure because of access to appropriate equipment and trained staff. When a nondomestic patient is treated at its residence, the type of restraint procedure used is governed by the onsite facilities and staff. Before a physical restraint procedure is begun, an evaluation of the procedure and patient is necessary: 1. Can the planned procedure be done with physical restraint only? 2. Will the procedure cause patient pain? If so, general anesthesia should be used. 3. Can the procedure be performed safely for the animal and staff? 4. Are the appropriate facilities, equipment, and staff available? 5. What are the patient's defensive weapons and how are the handlers protected? 6. How can the animal's flight distance be minimized to facilitate safe capture?
Perhaps the hardest thing to do is to back off from a manipulative procedure, whether it involves physical restraint or anesthesia. Many procedures require extensive coordination to be performed successfully. · Unless one is conducting an emergency procedure, if things are not proceeding according to plan, or if there is a factor that can be changed to enhance success, the procedure should be stopped and rescheduled. BASIC RESTRAINT EQUIPMENT
If a practice sees, or hopes to see, nondomestic patients, it should obtain basic restraint equipment (Table 1). The equipment required depends on the type and size of the patients seen. The following discussion is about basic equipment and its function and is not complete. The size of the equipment is patient dependent, but most of the equipment discussed can be used on a wide range and size of species. Hoop nets are a basic tool used to capture and restrain a wide variety of species, from small birds to mammals weighing up to about 20 kg. Nets are constructed of mesh or a sack, depending on the species and user preference. Nets vary in sizes and types, but the basic functional net is deep enough so when the animal is captured the net can either be twisted or flipped on itself to properly control the animal prior to its removal from the net. Newer nets with plastic rims may not be
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Table 1. BASIC EQUIPMENT AND TECHNIQUES APPLICABLE FOR RESTRAINT OR IMMOBILIZATION OF VARIOUS NONDOMESTIC SPECIES Patient
Net
Snare
Small Mammal Medium Mammal Hoofstock Primates Birds Reptiles
+ +
+
Plastic Tube
Gloves or Towel
+
+ ±
±
+ + ±
±
+
±
+
+ ±
Shield
Remote Injection
+ + + +
±
±
+ + +
+
±
Squeeze Cage
±
+
+
rigid enough to prevent the escape of some larger animals that lift the plastic rim (especially primates). Confined animals can be netted if a slow, purposeful movement is made, allowing the net to be placed over a stationary animal. The proper use of the net for capturing a moving animal is to anticipate where the animal will go and place the net in its path so that it enters the open net. Attempt to swing the net at the animals has two results; first, the animal probably escapes, or second, it can be hit and possibly injured by the net's rim. As with all equipment, nets become damaged and develop holes where animals have chewed through the mesh. All nets, therefore, should be checked prior to use. Nets and other capture equipment can become contaminated and act as fomites; therefore, they should be properly sanitized between patients. Protective gloves are commonly used to protect the handler from claws, talons, and teeth during capture and restraint. The glove's thickness should be appropriate to the patient, but many of the larger carnivores are capable of biting through most gloves or crushing fingers without damaging the gloves. In certain situations, the glove, without the fingers inserted, is presented for the animal to grasp and hold while capture is made using the other hand. Problems with the heavier gloves are the handler loses dexterity and has a tendency to apply too much pressure during the procedure, which can compromise the patient's respiration or cause other trauma. Gloves are also fomites and are difficult to sanitize properly between patients. A heavy towel is a versatile capture and restraint tool providing a visual shield and some protection against teeth and claws. The towel can be used in combination with gloves, if preferred. The towel is used to distract the patient and limit its field of vision during capture. Preferably, it is dropped over the patient to contain it prior to capture. The towel has the benefits of covering the animal's head and giving it something to grasp, both of which help to calm some animals. Although towels are fomites, they can be washed and sanitized after each use. Clear plastic tubes are useful tools for restraint and short transport procedures in small mammals and reptiles (Fig. 1). Various tube diameters should be available, because the proper tube size is about 10% to 15% larger than the patient's diameter, to allow some movement but to prevent the animal from turning around. The ends of the tubes can be plugged with towels or appropriate material to adjust the length of the
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Figure 1. A clear plastic tube is used to restrain a Black Footed Ferret for closer examination, and can also be used as an anesthesia chamber. (Courtesy of Lisa Ware, Conservation and Research Center, Smithsonian National Zoological Park, Front Royal, Virginia.)
chamber. A tube with slits or holes allows some access to the animal. Plastic tubes are also excellent chambers for induction with inhalant anesthetics. These tubes can be easily cleaned between patients to prevent the spread of disease. Handheld shields are useful restraint devices that also protect the handler. In smaller mammals, a clear Plexiglas shield with a handle is used to compress the animal to the rear of a cage. A shield with holes allows injections to be given (Fig. 2). Clear shields are useful for capturing some reptiles. Larger shields or crowding boards are used with hoofstock and are usually opaque, to obliterate the human shape. These boards are equipped with handles and should have a viewing port so that the operator can see and respond to the animal (Fig. 3). The shield is used to move or shift the animal or to allow a protected approach to the animal for observation or injection by a pole syringe. Snares are used to gain control of the animal's head for capture. These devices have been called Rabies poles or catch poles and are available commercially or can be constructed. When catching most mammals, catch the neck and one foreleg to preclude excessive tracheal pressure as the snare is tightened or if the animal struggles. A major problem can occur when the animal is snared only by the neck and if it starts to roll the noose begins to twist and tighten around the neck. When this occurs, the quick release does not work and as the animal continues to roll, the tighter the noose becomes. Squeeze cages are indicated if a moderate volume of nondomestic species is seen because they facilitate observation and treatment. The basic squeeze cage contains a movable wall that compresses the patient
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Figure 2. A clear plastic shield is used to confine a patient for closer examination or possible injection through the holes in the plastic. (Courtesy of Lisa Ware.)
to the opposite wall of the cage (Fig. 4). The walls are bars so that observations and injections are possible on the restrained animal, but the spacing of the bars can allow some patients to strike out at handlers. These cages can vary in size for small mammals up to the size that will handle large carnivores (tiger or bear). These larger cages usually require some type of mechanical advantage for the operator to compress the animal. Animals can be housed in these cages during treatment periods or shifted into them for treatment.
METHODS AND EQUIPMENT FOR DRUG ADMINISTRATION
Drug injection is central to many medical procedures, including medication, vaccination, and anesthesia. The method of drug delivery depends on drug volume and viscosity, type of patient, access to the patient, available equipment, and ability of the operator.
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Figure 3. A plywood crowding board is used to move this female Eld's Deer. Note the plastic view area in the crowding board. (Courtesy of Lisa Ware.)
Figure 4. A squeeze cage for restraint of small- to medium-size animals. The hand crank on the front of the cage moves the rear wall forward.
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Intramuscular Injections
When rapid absorption is desired, inject into the muscle mass because of the plentiful blood supply. The major muscle masses of the shoulder or the legs are preferred. Injections given subcutaneously (SC) in the neck or over the back are usually less desirable if rapid adsorption is required, because of a reduced blood supply. The hand syringe is the method of choice because it allows accurate and complete drug delivery when the patient is restrained properly. The tendency is to give the injection rapidly, but, if possible, the delivery should be slow to minimize pain associated with rapid stretching of muscles and nerves from the fluid infusion. Semiremote intramuscular (IM) injections are given using a pole syringe (Figs. 5 and 6). The pole acts as an extension of the syringe's plunger. The length of this extension pole can vary from a foot or two up to several feet, but with increasing length, there is added weight, decreased mobility, and less accuracy. The syringe is covered with a sleeve to guard against needle breakage and to prevent syringe breakage where the needle attaches. Pole syringes are commercially available or can be constructed rather easily. A dark-colored pole syringe slightly decreases the chance of its being seen by the patient. The drug injection begins on impact, and contact with pressure must be maintained with the animal for the duration of the injection. For small volumes (1 mL3 mL) this is not a problem, but for larger volumes of 6 mL to 12 mL, the contact and pressure must be maintained for 1 to 2 seconds. Contact
Figure 5. Three pole syringes, which can be used for injections at a distance. The top pole is a 3 ml capacity syringe, which is empty. The middle 6 ml syringe pole has been loaded with 3.5 ml of drug. The bottom 12 ml syringe pole has a needle guard over the needle to prevent breakage of the needle and/or hub of the needle. Note piece of tape holding the needle guard in place. (Courtesy of Lisa Ware.)
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Figure 6. The use of a 3 ml pole syringe to inject a female Eld's Deer. (Courtesy of Lisa Ware.)
time can be decreased by using large-gauge needles (14- or 16-gauge), but these tend to lacerate the moving animal during an injection. Most patients soon learn to recognize the pole syringe and present a moving target. In these cases, an attempt first to confine the patient is made, the patient's movements are anticipated, and the pole follows the animal's direction during the injection thrust. The use of the dart gun at first seems to be the answer to all problems associated with remote delivery of drugs in uncooperative nondomestic species, but each darting system has certain disadvantages that should be understood. The use of any remote darting equipment requires the precaution and judgment mandatory when handling any firearm. The proper use of the projectile syringe requires marksmanship and practice, first on inert targets to understand the gun's sighting and how to minimize dart impact. Other variables to be considered with each shot include target distance and how to compensate by aiming or adjusting the propellant force of the delivery system. Second, the size and weight of the dart determines the propellant force necessary to hit the target. Wind currents particularly influence large darts that are . projected for long distances. For a historical review of remote delivery devices, the reader is referred elsewhere. 1 Historically, the explosive projectile darts for IM injections were the standard method for remote drug delivery to large mammals. The primary dangers of these systems when used improperly were high-energy body impact, causing extensive muscle damage, fracture, or body cavity penetration. The current delivery systems use less
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traumatic, lightweight plastic darts (Fig. 7). These darts have several basic components: 1. The needle's hole is on the side (not the end) and a moveable
sleeve covers it. 2. The syringe barrel (1 mL-10 mL) contains a moveable plunger anterior to a sealed compartment. 3. The dart contains a tailpiece to facilitate aerodynamic flight. The drug is placed in the syringe barrel in front of the movable plunger, and the needle is attached. The moveable sleeve covers the hole on the side of the needle. The chamber behind the moveable plunger is pressurized with air or liquid butane, placing a compressed force on the drug compartment. The dart is placed in a delivery device, which can be either a blowpipe (using lung pressure) or COrpressured injection devices. When the dart's needle penetrates the skin, the sleeve is pushed posteriorly, uncovering the hole and allowing the pressurized drug to be injected as the plunger is forced forward. Some patients do not even realize that an injection has occurred. The delivery range varies with the propelling system; using lungpower, a dart can be delivered accurately up to 10 to 15 meters; other systems using compressed air or a powdercharged rifle allow effective ranges of 40 to 60 meters. When butane is the pressurizing agent, cold temperatures can inhibit butane's expansion characteristics, preventing complete drug injection and thereby limiting the effectiveness of this delivery system.
B
Figure 7. A diagram of an air pressurized plastic dart. 1 = drug chamber; 2 = pressurization chamber; 3 = one-way valve. A, Pressurized dart in flight. B, Dart in final stage of injection. (From Bush, M: Remote drug delivery systems. J Zoo and Wildl Med 23:159-180, 1992; with permission.)
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CAPTURE AND CONTROL
Basically, physical restraint has two phases, first capture and then control of the patient. The actual physical capture has several stages, all of which can be assisted by planning, experience, and equipment. It is desirable to capture the animal from a small enclosure or crate, which allows the operator good vision and room to orchestrate the capture. The animal should be captured in a timely manner, with minimal excitement and trauma, using controlled, purposeful movements and limited noise. These ideal criteria are not always achievable goals, however. The control phase of the restraint procedure depends on the species and the procedure to be performed. Basic guidelines for this phase are that the restraint is firm with total control that is not excessive or traumatic, but this balance can be a difficult to achieve without extensive experience. In smaller patients, when heavy gloves or nets are used, care is taken to monitor any respiratory compromise. Covering the eyes helps calm some species during a restraint procedure. Talking, extraneous noise, and unnecessary patient movement should be avoided to limit stimulation of the patient. Nondomestic patients seen in practice situation which require manipulative procedures can be categorized as follows: 1. Small mammals (<5 kg) 2. Medium-sized mammals (5 kg-10 kg) 3. Small to medium hoofstock (:s:400 kg) 4. Primates 5. Birds 6. Reptiles Small Mammals
This section does not include the "pocket pets" (i.e., ferrets, hamsters, chinchilla, mice, or hedgehogs) which are restrained in a manner similar to domestic dogs and cats. Usually, these patients are accustomed to handling and pose no unique problems. On small nondomestic mammals of 5 kg or less, minor manipulative procedures previously were accomplished using physical restraint by means of gloves or nets. Physical restraint still can be the method of choice for minor short procedures that entail minimally painful stimuli (i.e., vaccinations, ear tagging, nail trims). Any extensive procedure or surgical manipulation requires general anesthesia. The use of clear plastic tubes offers a simple way to confine a small patient for better observation and control. The animal is directed from a nest box, net, crate, or from a hand capture into a tube about 10% to 15% larger than the patient's diameter. Initially, the tube can be covered with a towel to let the tube appear as a dark hiding place. The tube can be plugged with a towel at each end. Once the animal is in the tube, close observation is possible. The tube also can be used as an anesthetic chamber for induction with inhalant anesthetics.
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Plastic shields restrain and confine caged small mammals for closer observation or administration of injection. The shield restricts the patient's space by pushing it up against the wall of a cage. The shield should be clear and have a handle for the operator to use while applying pressure to the animal. The size of the shield should be slightly smaller than the dimensions of the cage it is used in. It is helpful to have several slits or holes in the shield to allow injections of medications or anesthetics. Many small mammals are presented in small kennels, and the challenge is to remove them from their crates and proceed with the restraint. There are several approaches to this situation. A net can be inserted and the animal netted prior to removal, but this can be a problem (e.g., the opening of the kennel is usually smaller than the size of the desired net). In some patients, a heavy towel is used to limit the animal's view while it is pressed against the far wall and grasped. It is usually difficult to get the animal transferred to a squeeze cage because the animal prefers to stay in the kennel. One could have the client build a movable wall in the back of the kennel that could be used to force the patient to the front of the cage into a squeeze cage, net, or plastic tube. As a last resort, a snare pole can be used to secure and remove the patient. Medium-sized Mammals
These animals are the upper limit that can be managed with nets or gloves; therefore, the use of a squeeze cage is recommended. A squeeze cage facilitates minor procedures on medium-sized to large mammals by allowing close visual examination, administration of medication, and injection of anesthetic by hand syringe. HOOFSTOCK
This diversified group of mammals varies markedly in temperament and physiology, which dictates the need for various handling strategies. This section discusses cervids and bovids up to 400 kg. Generally, loading and routine management movement of hoofstock can be accomplished without anesthesia. Adequate runways, chutes, and crates are required to facilitate animal separation, shifting, and confinement. Conditioning and the animal's familiarity with the facility allow nonstressful crating for shipment or for a medical procedure. 8 The greatest chance of success occurs if the following criteria are met: 1. The facility's restraint location is accessible to the animals by
runways from other enclosures. 2. The runways and gates allow movement and separation of animals by remote controls. 3. The floors provide sure footing, allow drainage, and can be readily sanitized.
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4. The walls are solid, smooth, and sufficiently tall to discourage the animal's attempt to climb or jump. 5. Observation ports are available to monitor the animal's position and condition during the procedure. 6. The design permits forcing the animal into a more confined area and eventually into a crate, squeeze chute, or trailer. Physical restraint of small hoofstock (<15 kg) is appropriate for minor procedures (i.e., bleeding, worming, medicating). The major risk is not the physical holding of the animal, but rather initial capture in the enclosure or cage. Nets are useful, but there is a chance of injury from improper use, which can entangle a leg. The rigid net hoop can also cause trauma. In addition to confinement in a standard cage or catchpen, 10 an animal can be confined into a corner with handheld wooden shields (crowding boards) or with a curtain of an opaque material (e.g., plastic sheeting). The use of crowding boards or a curtain protects the staff, obscures the outline of the human form, and decreases the flight distance, while reducing excitement. Actually grabbing an animal requires skill as well as knowledge of the animal's potential for injuring itself or the handler. The sharp hooves and powerful rear legs of small hoofstock are capable of cutting through clothes and skin. The sharp horns of small-sized antelope, and, in some species, teeth (i.e., muntjacs, Muntiacus sp.) can cause severe punctures or lacerations of the handler. Once caught, the animal's body is wrapped around the handler's hip, so that the powerful back muscles are misaligned, thereby minimizing effective kicking. Grasping the horns or antlers offers a good method of controlling the animal's head and movements. Caution is needed when handling cervids with developing antlers (in velvet) as they can abrade and fracture easily, with extensive bleeding and resultant malformation of the mature antler. Similar precautions are needed when grasping the horns of immature bovid because these are loosely attached and can be permanently damaged. Physical restraint of larger-sized hoofstock requires a shield, chute, or squeeze cage. Bovids usually tolerate more physical restraint and manipulation than do cervids. Some medium-sized antelope can be slowly crowded into a corner. They can then be made to lie down, allowing minor procedures to be performed. This judgment comes with knowing the animal and being able to read its reactions. For handling larger species of bovids or cervids, some modified commercial cattle chute with covered top and smooth, solid sides is one option for minimizing injuries during struggling. Once the animal is secured, side boards on the chute can be removed to gain access to the animal. The head catch of commercial chutes is dangerous because some animals tend to twist or spin once the head is secured, a potentially fatal maneuver. Physical restraint in excitable hoofstock can result in capture myopathy.7· 9 In many situations, anesthesia involves less risk to the patient and the handlers. In most facilities that routinely physically handle larger hoofstock, a drop-floor chute or a hydraulic squeeze chute is preferred. Both devices apply lateral compression and position the animal's feet
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off the ground to help preclude struggling. Having better access to the animal and the increased safety to animal and handler can offset the initial cost and result in significant cost savings from repeated use of anesthetic drugs. Primates
Primates increasingly are not being kept as pets and therefore are not being seen by practitioners. In rare circumstances when minor nonpainful manipulations are performed, physical restraint could be used for smaller primates (<2 kg). Primates are strong, fast, and can inflict severe bite wounds. To facilitate safe capture and restraint, nets and gloves are commonly used. The recent concerns about herpes B virus has all but stopped any physical restraint procedures on macaques (Macaca sp.) which are carriers of the virus. All procedures should be performed on macaques that have been anesthetized using dissociative anesthetics. Most other primates can harbor potential zoonotic diseases, and appropriate safeguards are recommended, in addition to owner counseling. A squeeze cage is indicated for procedures on medium-sized to large primates because it allows visual examination, administration of medication, and injection of anesthetic by hand syringe. AVIAN SPECIES
This group covers a wide range of species and sizes, ranging from small finches to ostriches. This section groups birds into five groups: (1) small caged birds, (2) psittacines, (3) raptors, (4) cranes, and (5) ratites. Small caged birds are many times the most difficult to capture and restrain physically because of the associated problems of stress. Capture is facilitated if the bird is alone in a small cage with subdued light. Small nets are placed in the expected flight path of the bird for capture. Once netted, the bird is carefully removed, taking care not to injure legs, wings, or toes. The head is supported between the thumb and forefinger with the body of the bird, with the wings folded, lightly encircled by the hand. Once secured in this position, the legs and wings can be extended carefully for examination or treatment. The bird is released so that it does not wildly fly off and hit the cage wall or ceiling. Psittacines, especially the larger parrots, are strong birds and can inflict severe wounds with their bills. The first goal is to control the head and beak with one hand, while the wings are wrapped to prevent flapping and injury. The legs are grasped with the other hand. Initial capture is usually done with a net or a very heavy towel placed over the bird's head. A clear plastic shield can be use to crowd a parrot to the back of a cage before the head is grasped. The larger parrots are not for the novice because they can produce severe bite wounds. The restrained bird is usually very vocal; this should be anticipated and the head covered to help calm the bird.
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When restraining raptors, take care to avoid the talons, which can inflict major painful wounds. The beak is also capable of creating a nasty wound. The initial capture usually is done with a net; the talons must be secured first, then the beak, before the bird is removed from the net carefully so as not to entangle it and cause injury. Placing a hood over the head to cover its eyes can help to calm the bird and facilitate the procedure; if the head must be examined, it is best to leave the bird hooded for a few minutes then remove the hood slowly for the exam. Heavy gloves and towels can be used as an alternative for a net for capturing raptors that are on the ground or in a cage. Ideally, the bird should be approached from above and behind, and the towel is used as a shield. The bird is then wrapped in the towel, taking care again to secure the talons and beak before proceeding with removing the bird from the towel. With some calmer raptors on a perch in a small cage, it is possible to use a newspaper to shield the bird's vision as one grasps both legs with a gloved hand. One must gain control of both legs with this procedure. This technique requires some practice and coordination and is best practiced on smaller raptors first, but once mastered, it is a rapid and less stressful method of capture. Cranes can be encountered as wild birds or from an aviculturist. They present some unique physical restraint challenges. Cranes are large birds with powerful wings and legs and a pointed bill, all which can be used as weapons. It is recommended that eye protection be used when handling them. The nails are capable of causing painful dirty wounds in addition to the pounding and bruising from their strong wings. The best capture method is usually to herd them into a comer and grasp the wings from behind, putting some downward pressure on the back to prevent the bird from kicking out with the legs and cutting the handler or themselves with their sharp nails. Once the crane is secured, the head is controlled and the bird is lifted with the body held under one arm, with its wings folded. The feet are held out in front of the handler and the head and neck extended behind. It is best not to fold the bird's legs when holding them, especially if the restraint is to be prolonged, because this can lead to muscle stiffness. If the bird is very aggressive, a second person is sometimes required to hold the head and neck. Hooding a crane is indicated to calm the bird. Both legs should be held together with a finger separating them to avoid their scraping against each other. Releasing the bird must be done with care to avoid injury. Again, one must watch for the bill while placing the bird's feet on the ground. Exert downward pressure on the legs so that the bird does not kick or rake itself as it is released. Ratites
Ostriches and emus have become popular in some areas and are raised as a commercial venture. Adult ratites are difficult to restrain physically because of their great strength and size. They are capable of causing major injury to themselves or handlers. Birds of 3 to 4 feet tall
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are the largest that can be restrained safely. The key is to approach the bird from behind to avoid being kicked. Restrain the bird by grasping the rudimentary wings to gain control. Once this is done, grasp both legs and assist the bird to lateral recumbency, with the legs held extended posteriorly. Hooding these birds is indicated to reduce stress. Larger ratites can be herded into confined areas by using a crowding board, but their kick can break such boards. Once the bird is in a confined area, closer examination is possible, and injections with a pole syringe can be done. REPTILES
Reptiles include a wide variety of species that require different handling strategies. Probably the most common reptile presented to the practitioner is a snake. (This discussion does not include the handling of venomous species.) Most snakes kept as pets are usually handled by the owner; this allows a fairly detailed physical examination and medication administration. When handling any snake, be aware that Salmonella spp. is a common bacteria found in most reptiles and poses a possible zoonotic problem. Even the calmest snake can bite, and they usually break off teeth, which can act as a foreign body in an infected wound. To transport snakes, a soft cotton bag is recommended. When the snake is to be captured, the bag can be collapsed on the snake and provides a shield and some padding when the handler pins and extracts the snake from the bag. Plastic tubes are also an excellent way to restrain and examine the snake. The diameter of the tube should be about 20% larger than the snake's diameter to prevent the animal from getting stuck, while preventing it from turning on itself. The snake can be enticed or placed in the tube. For some procedures, after the snake is partially in the tube, the snake and the tube are grasped together to secure both the snake and the tube. This leaves a portion of the snake exposed, and the snake also can be repositioned for exam or treatment of other areas. The tube can be used as an induction chamber for inhalant anesthesia. The classic method of catching and restraining snakes has been the use of a snake hook or tongs and when used by an experienced herpetologist-these are useful tools. When used inappropriately, they can cause injury to the snake. Two mistakes often made with a snake hook are applying too much pressure just behind the head when the snake is pinned (which can be minimized if a foam pad is placed under the snake's head prior to pinning it) and dangling a large snake by the hook, which applies too much point pressure to the animal's spine, which predisposes it to injury. Padded tongs are an acceptable method of capturing a snake so that it can be grasped behind the head, but again, care must be taken to avoid unnecessary pressure. The snake hook and tongs can be used to direct a snake into a tube or a bag for further restraint or capture. A plastic shield is useful to pin a snake to
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the bottom of a box to assist in the capture. After capture, the snake's head is grasped with the thumb and forefinger for control. When holding a snake, always support the body when lifting or carrying it, to prevent spinal injury. Many snakes will wrap around the holder 's arm, which supports the weight, but this method can be a problem in large constrictors, which should be handled only when enough experienced people are present (about one person per 1 meter of snakelength). When capturing and restraining lizards and monitors, the handler should be aware of the two defensive weapons they have: the mouth, which contains sharp teeth, and the tail, which can lash out and strike the handler, also potentially damaging the animal's tail. The object is to grasp the head and block the tail from flaying as it is grasped. Plastic shields are useful in controlling or pinning the animal prior to grasping. Following initial capture, the animals can be placed in a plastic tube for further examination, transport, or induction of gaseous anesthesia.
CROCODILIANS
Physical restraint is practical for animals up to 1 meter. The crocodilian' s weapons include the mouth and tail. Keeping the mouth securely closed is the best method of control. For the initial capture, a snare pole can be used to grab the mouth, keep it closed until the animal's mouth is better controlled with both hands or by taping the mouth shut. After the mouth is controlled, attention can be shifted to the tail, which can lash out and injure the handler. With the head and mouth secured by a snare pole, the pole is then aligned with the animal's body and the tail is grasped and stabilized against the pole.
References 1. Bush M: Remote drug delivery systems. J Zoo Wild! Med 23:159-180, 1992 2. Bush M, Custer R, Smeller JM et al: Physiologic measures of nonhuman primates during physical restraint and chem ical immobilization . J Am Vet Med Assoc 171:866-869, 1977 3. Chalmers GA, Barrett MW: Capture m yopathy. In H off GL, Davis JW (ed s): Noninfectious Diseases of Wildlife. Ames, Iowa State University Press, 1982, pp 84-94 4. Fowler ME: Restraint and H andling of Wild and Domestic Animals. Ames, Iowa State University Press, 1978 5. Harthoorn AM: The drug immobilization of large herbivores other than antelope. In E. Young (ed): The Capture and Care of Wild Animals. Cape Town, South Africa, Hum an and Rousseau , 1975, p 52 6. Harthoorn AM: Restraint of undomesticated anim als. J Am Vet Med Assoc 149:875880, 1966 7. Harthoorn AM, VanderWalt K: Physiological aspects of forced exercise in w ild ungulates with special reference to (so-called) overstraining disease, 1. Acid-base balance and PO levels in blesbok (Damaliscus dorcas phillipsi). J South Afr Wild! Mgmt Assoc 103:64-68, 1974 8. Harthoorn AM: The u se of corrals to capture and train wild ungulates prior to relocation. Vet Rec 104:349, 1979
PHYSICAL RESTRAINT TECHNIQUES AND IMMOBILIZATION EQUIPMENT
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9. Hofmeyr JW, Louw-GN, de Preez JS: Incipient capture myopathy as revealed by blood chemistry of chased zebras. Madoqua 7:45-50, 1973 10. Jones DM Physical and chemical methods of capturing deer. Vet Rec 114:109-112, 1984 11. Wiesner H: Tranquilization by the blowgun rifle method. Kleintierpraxis 22:327-330, 1977
Address reprint requests to Mitchell Bush, DVM Conservation and Research Center Smithsonian Institution 1500 Remount Road Front Royal, VA 22630 e-mail: [email protected]
APPENDIX
Sources of Equipment Remote Injections Pole Syringe Zoolu Arms of Omaha 10315 Wright St. Omaha, NE 68124 (805) 397-4983
Dart Gun (Daniject) Wildlife Pharmaceuticals 1401 Duff Drive Ft. Collins, CO 80524 (303) 484-6267
Nets/Snares/Snake Hooks Fuhrman Diversified 2912 Bayport Blvd. Seabrook, TX 77586-1501 (281) 474-1388
Nets Memphis Net & Twine Con, Inc. 2481 Matthews Ave. P.O. Box 80331 Memphis, TN 38108 (901) 458-2656
Animal Care Equipment and Services, Inc. P.O. Box 3275 Crestline, CA 92325 (800) 338-ACES
Hoofstock Chutes Fauna Research, Inc. 8 Bard Ave. Red Hook, NY 12571 (914) 758-2549
Reptile Equipment Midwest Custom Products, Inc. 14505 S. Harris Rd. Greenwood, MO 64034 (816) 537-4444
Other Related Equipment Nasco 901 Janesville Ave. Fort Atkinson, WI 53538 (920) 568-5600
Squeeze Cages Bryan Research Equip. 400 Stone City Drive Bryan, TX 77801 (409) 778-3100