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In recent years, the importance of providing a fear- and stress-free experience during veterinary visits and hospitalizations has been recognized by most practitioners and their teams. Despite our best efforts, there are still those patients who react poorly to the traditional methods of sedation, such as intramuscular (IM) injections. Perhaps, these patients are too smart and have experienced an IM injection before, so they object to the pain associated with it or they are extremely resistant to being restrained for it. This article will discuss the concept of FAS (Fear, Anxiety, Stress) scoring and its usefulness in every day practice, as well as some newer techniques that can be utilized to allow sedation to be administered in the least offensive way possible.
FAS scoring has become more widely adopted in veterinary medicine as of late. The scale used by Fear Free Pets is a 0–5 scoring scale and evaluates different body language, postures, the presence or absence of vocalization, and other behavioral clues to provide an as objective as possible description of the level of stress each patient experiences during their time in the hospital (Figure 1). It can be a very useful way to communicate between members of a veterinary hospital’s team, or even from hospital to hospital when a referral may be necessary.
In addition to improving communication, it also increases the safety of both the staff and the patient. If the patient were to need general anesthesia, obtaining a low FAS score before the procedure will also improve the overall anesthetic experience, lowering catecholamine levels, providing a smoother intraoperative event and a better, smoother recovery. As FAS scores increase in patients, the need for pharmaceutical intervention also increases. A patient with an FAS score of 2 may just need prehospital sedation with gabapentin and trazodone, but a patient with an FAS score of 3 or greater would most likely require injectable sedative medications through the IM, IV, or Governing Vessel 20 (GV20) route.
Traditionally, the IM route of drug administration has been the most commonly utilized one for fearful, hyperactive, or aggressive patients. Common administration sites for IM injections include the epaxial, hamstring, or quadriceps muscles. Intramuscular injections are often associated with discomfort and pain, and many animals, both dogs and cats, object to them.
In recent years, the acupuncture site known as the Governing Vessel 20 (GV20) has become a more commonly used site to inject premedication, notably alpha 2- agonists or opioids. In both people and dogs, stimulation of the GV20 acupuncture site has been shown to induce sedation.5 The GV20 site is located at the dorsal midline of the skull and can be found at the intersection of imaginary lines extending up from the rostral ear base or by palpation just rostral to the end of the sagittal crest (Figure 2). The mechanism of action is thought to involve the locus coeruleus in the brainstem, which helps to promote sedation by decreasing norepinephrine release and promoting endogenous opioid and other neurotransmitter modulation.1
The injection of alpha-2 agonists, such as dexmedetomidine or Zenalpha, and/or opioids subcutaneously (SC) into the area is called pharmacopuncture, and the theory is that the sedation caused by these drugs and the receptors they act on potentiates the sedation provided by acupuncture itself. Several studies in dogs have found the level of sedation to be much heavier and longer acting when dexmedetomidine is injected SC into the GV20 site as compared to an IM site.1,2 Another study in dogs has found that a lower dose of hydromorphone was needed to provide the same level of analgesia when injected via the GV20 site compared to IM.3 Studies in cats are ongoing, but one that was recently published showed comparable sedation between GV20 and IM injections. This study also showed significantly better sedation with GV20 than interscapular SC injections in cats.6 There are no studies looking at the use of Zenalpha given via the GV20 route, but this drug has been used extensively at the author’s institution and subjectively provides more reliable sedation at lower doses than if it were given IM.
It seems counterintuitive to give an injection SC in the head of a nervous or aggressive dog, but it is surprisingly well tolerated at the author’s hospital without forceful physical restraint. Often times the patient can be distracted by placing a muzzle or holding something in front of them, such as a small amount of peanut butter, as the GV20 injection is performed. A butterfly catheter can also be utilized to allow the technician to remain a bit further away from the patient. Many dogs do not even seem to notice the injection with a small needle into the SC space at the GV20 point, and it seems to be much less painful than an IM injection.
Despite the GV20 technique being well tolerated in most, some dogs object to any manipulation of the head and in that case another technique can come in handy. The “walk and poke” technique is extremely useful in aggressive or extremely fearful dogs. This technique is very useful because it does not involve any physical restraint for the injection. If possible, an e-collar or muzzle is placed on the dog, and one team member simply walks them on a leash down a hallway while another team member follows behind, prepared to administer the sedative into the epaxial muscles. The team member performing the injection will administer the drug via a syringe attached to a microbore extension with a needle on the end of it (a 22-gauge needle is fine). The syringe should have one ml or so of air in it that can be injected to “flush” the drugs through the longer microbore extension line (Figure 3). The key is to walk the dog forward at a calm and moderate pace without looking back at the team member holding the syringe and to quickly poke the needle into the epaxial while walking and injecting the drugs. The needle will stay put in the epaxials as the dog walks and the injection is very quick. Most dogs do not know what the small poke was, and although they may look back, overall, they tolerate this technique very well.
Veterinary medicine has come a long way over the last few decades, and we are now very capable of providing a reassuring and fear-free experience for our patients with the use of prehospital sedation and different/novel injection techniques. The days of holding animals down or pinning them between a door and a wall to give injections are (or at least should be) long gone. All it takes is the willingness to try something new and the ability to get a little creative. And don’t forget, patience is a virtue, and your patients will thank you (as well as their humans).
