Chemical Immobilization: Human Safety and Accidental Exposure

Chemical Immobilization: Human Safety and Accidental Exposure is one of the courses covering the principles of and techniques relating to chemical immobilization, pharmacology and drug delivery systems offered by the San Diego Zoo Wildlife Alliance (SDZWA). This education in capture and chemical immobilization is offered for those who are interested in or who are pursuing careers in veterinary medicine, wildlife management, biology, zoology, animal control or continuing education credit.

The agents used in chemical restraint of animals, whether domestic, managed, or wild, are potentially hazardous to humans. In recent years, some drugs required to safely immobilize a variety of species have been modified to increase their concentrations into smaller volumes, thus increasing the potency of each drop.

As we know, there is great public concern related to the abuse of opioid drugs in the human population. Some of the drugs used in the chemical immobilization of wildlife are opioids; while others belong to different classes of drugs, they are nevertheless potent and potentially dangerous when misused, mishandled, or accidentally ingested. Humans have died from accidental exposure to Xylazine, Etorphine, Ketamine and Tiletamine/Zolazepam (Telazol®), so the risks are real.

The information in this article has been adapted from the SDZWA course Chemical Immobilization: Human Safety and Accidental Exposure.

Routes of Exposure

Some of the ways in which accidental exposure to immobilizing drugs can occur include:

• Through broken skin
• Via the mucus membranes on the inside of the nose or mouth
• Via contact with the inside of the eyelids
• Breathed into the respiratory system

Some scenarios in which contact as described above could occur include:

• With the user’s hands otherwise full, they use their mouth or teeth to remove a needle cap
• A dart goes off as the user attempts to load it, spraying drugs into their eyes
• The port in a needle from a pressurized dart leaks, allowing drugs to drip into an abrasion on exposed skin
• A dart is accidentally fired into the user or another person
• A leaky dart passes through the mouthpiece of a blowpipe
• A glass bottle of powdered drugs is dropped and breaks; the powder aerosolizes and is breathed
• An unlabeled dart that contains minute quantities of drug inadvertently splashes from the sink into one’s mouth as they clean darts whilst they carry on a conversation
• A carelessly handled needle scratches one’s skin

In order to avoid these exposure scenarios, teams and organizations handling immobilizing drugs should implement general protocols for avoiding accidental exposure.

Protocols: Prevention and Response

There are specific safety protocols that should be followed for specific drugs and equipment. However, it’s important to establish baseline safety precautions and protocols that teams and organizations handling immobilizing drugs should follow no matter the substance or equipment being handled.

The list of protocols can be remembered using the acronym STAR:

• Safety Team
• Antagonists
• Response

Safety Team

Any person handling ultra-potent drugs or darts that contain(ed) them should be accompanied and monitored by a person who is trained in the following:

• Institutional emergency protocols
• Expired Air Resuscitation (EAR) and cardiopulmonary resuscitation (CPR)
• Administration of reversal agents by injection

Prior to immobilization, associated personnel should be made aware of the identity of the drugs involved and precautions to be taken if inadvertent exposure occurs.

Antagonists

Prior to manipulation of dangerous drug vials and their contents, it’s important to record on the name and amount of all drugs in use, including any available antagonists/reversal agents.

When working with any ultra-potent drug, whether it be narcotic or any other super-concentrated agent, the antagonists should be drawn in advance into syringes that are clearly labeled with drug name and dose at the appropriate dosage for the animal. Dire life-saving circumstances may necessitate the use of these antagonist “ready syringes.”

It should be noted that while some opioids (e.g., Carfentanil, Thianfentanil, Etorphine, Butorphanol) do have human-approved antidotes available, some other drugs do not.

Response

In order to establish protocols and lay out expectations and precautions for a procedure and possible emergencies, teams and organizations handling immobilizing drugs should initiate conversations with local physicians, restraint team members, and appropriate institutional representatives. Preparation and properly applied basic life support practices can lead to successful treatment in case of accidental drug exposure.

Three protocols should be established for the event of accidental exposure:

• Considerations for treatment in the field before medical assistance arrives
• Considerations for treatment by EMT personnel on-site and in transit to hospital
• Considerations for treatment by ER physicians upon hospital arrival and triage

To facilitate proper implementation of these protocols, printed, laminated versions should be kept in the team’s capture kit. Human medical response personnel will need to be alerted as to the identity/affiliation of the involved parties and what drugs they are working with as rapidly as possible.

Some strategies that have been used by teams and organizations handling immobilizing drugs include:

• Medic alert bracelet(s) or necklace(s) with name(s) of the drug(s)
• Writing the name of the drug(s) being used on one’s arm
• Wearing a pouch within one’s pocket or around one’s neck that contains the specific drug inserts
• Isolating the specific drug inserts in a transparent plastic bag or sleeve at the top of the accidental exposure kit

To further assist response and medical personnel, the drug inserts (which contain chemical descriptions of the drugs being used) can be included prominently in the team’s accidental exposure kit. These can be provided to health care personnel for background information in cases where they may be unfamiliar with these veterinary drugs.

Interested in learning more about safe capture? The San Diego Zoo now offers courses in safe capture techniques and best practices. Learn reliable, safe, and effective techniques for the species you work with and the scenarios you encounter!