Medical News
Rabies One of the threats that tactical teams face is the presence of dogs and other wild and domesticated animals on the scene. The animals pose a risk to the team members and the tactical team medic needs to train team members how to prevent injury, as well as treat the team member that has been injured by an animal. The transmission of rabies by an animal to a human should be of paramount concern for the team and tactical medic. Rabies is a virus transmitted by an infected animal to another animal or human via saliva. It may also be transmitted via inhalation of the aerosolized virus in bat infested caves. There is no risk of blood borne transmission. Although all mammals can theoretically carry and transmit the virus, a few species are responsible for the majority of the cases reported to the CDC yearly. In the US and Puerto Rico in 1991, the rabies cases were distributed as follows - 44% raccoons, 30% skunks, 5% bats and 5% in foxes. In Canada, foxes account for greater than 40% of the cases while skunks account for 20% of the cases reported.
The rabies virus is transmitted via saliva into a wound by a bite, or less often, a lick. The virus can also be transmitted by inhalation in a bat infested cave, when the saliva is aerosolized and inhaled. It is then transmitted across the neuroepithelium of the nasal cavity.
The virus causes illness by traveling up the peripheral nervous system at approximately 3 mm/hr to the central nervous system (CNS). The usual incubation period is 2-16 weeks, al-though periods as short as 9 days and longer than one year have been reported. The closer the bite is to the CNS, the sooner the symptoms will occur. The symptoms usually start with nonspecific findings, which progress into more specific neurological signs and symptoms. Initial findings include fatigue, anxiety, agitation, nausea and vomiting. Local pain at the bite site is reported in 50% of the cases. More specific neurological findings include increasing agitation, seizures, alternating periods of aggressiveness and calm, and hallucinations. The classic "hydrophobia" reaction can be explained physiologically. As the disease progresses, the patient or animal suffers severe pharyngeal or respiratory muscle spasms when they attempt to drink water. Later on in the disease process, even the sight of water can trigger the spasms- thus the term "hydrophobia".
Preventive care includes screening team members' medical records and ensuring that their tetanus shots are up to date. All members should have a tetanus booster within the last five years, since most wounds sustained in the tactical environment are considered high risk for tetanus. In the event a team member is bitten or injured by an animal, wound care procedures should be undertaken as soon as possible. The wounds should be cleaned at the scene, if possible, with copious irrigation, prior to evacuation. The animal should be identified and captured, if doing so does not incur further risk to team members safety. If possible, the animal should be contained for the arrival of animal control authorities. The animal will be quarantined and examined. If the animal is destroyed, its carcass should be turned over to animal control for necropsy and rabies testing.
If the animal has been captured and quarantined, no further rabies treatment is needed, pending the results of the animals' examination. if the animal is deemed not to have rabies after a 10 day quarantine, then no further care is needed. If the animal is diagnosed with rabies, or was not captured, the team member needs medical evaluation and started on the rabies vaccine as soon as possible- but not later than 24 hours after the exposure. The vaccine is usually started by the health department, but the initial evaluation and treatment can be carried out in the Emergency Department of your local medical facility.
The rabies vaccine consists of two medications - the Human Rabies Immune Globulin (HRIG) and the Human Diploid Cell Vaccine (HDCV). The dosing schedule is depicted below:
If the medic is unsure of how to care for a potential animal bite or exposure, Emergency or Health Department personnel should be consulted. Rabies is almost always uniformly fatal once the patient exhibits symptoms. It is always better to treat the patient if there are any questions as to whether an exposure occurred or not.
The area of operation in the law enforcement tactical setting is normally defined by the terms "inner perimeter"and "outer perimeter". Although different meanings are ascribed to these terms in various regions of the country, the "inner perimeter" is generally a geographically-defined area in which subjects are contained, with entrance and egress controlled by the SWAT team. The "outer perimeter" is that larger area, encompassing the inner perimeter, which is controlled by the law enforcement agency and from which the public is excluded . These areas are frequently thought of as concentric circles with the tactical target lying in the center.
This concept of inner and outer perimeters is critical to the containment of an incident and has utility in planning and implementing tactical options. However, it does not have a good application to Tactical Emergency Medical Support (TEMS) decision making, despite its frequent use in that context.
There are three zones or echelons of medical decision-making in TEMS. In testimony to my lack of creativity, I have called them the "hot zone, the"warm zone" and the "cold zone". The hot zone is that area in which the EMT-T and/or the patient are subject to a direct and immediate threat. What constitutes a direct and immediate threat is subjectively determined and dependent on the specific mission circumstances. A subject with a gun and a clear line of fire would certainly constitute a direct and immediate threat. Exposure to an are where the subject might be located, but has not yet been seen, would be insufficient by itself to constitute a direct and immediate threat.
Assessment and treatment in the hot zone incurs enormous risk. Self care or auto-extraction (moving one's self to a safer area) may be possible. TEMS personnel may perform a re-mote assessment using Rapid and Remote Assessment Methodology (RAM) techniques. Usually, extraction, whether by self or others, is the only appropriate intervention in the hot zone. In some cases, extraction may need to be deferred because of extraordinarily high risk to the provider or low probability of a successful extraction. This is consistent with the widely accepted medical precept of doing the greatest good for the most number of people.
The cold zone is that area where no significant danger or threat can be reasonably anticipated for the provider or patient. This may be due to the interposition of distance, time, terrain features or firepower between the provider and the threat. TEMS decision-making in this circumstance is almost identical to everyday EMS decision-making, with the possible exception of increased awareness of forensic considerations. Injured per-sons in the cold zone may be evaluated and treated without risk.
The warm zone is that area in which TEMS decision-making is most dramatically affected. It is defined as that area in which there is a potential hostile threat, but the threat is not immediate or direct. Here, the threat is often poorly defined and highly dynamic. For example, the grounds immediately surrounding a house where the subject is believe to be contained would be considered a warm zone. If an armed subject were in the window, it would be a hot zone. If intelligence assets confirmed that the suspect had left the area, then it could be considered a cold zone. It is in the warm zone where the benefits of medical evaluation and treatment in situ must be carefully weighed against the risk of remaining in the warm zone and delaying extraction. It is here that the difficult and defining decisions of TEMS must be made. Should CPR be initiated? Should a backboard be applied? Should an endotracheal tube be inserted?
Multiple factors must be considered in only fractions of a second. Among these factors is the relative threat level. Not all threats are equal. Some are more severe than others for a variety of reasons including credibility, intelligence, type of weapon (if any), nature of injuries which could be inflicted and consequences of being wrong in your threat assessment. Some warm zones are simply warmer than others.
The potential benefit of any medical intervention must also be considered. Spinal immobilization is of comparatively little value in patients with penetrating neck wounds. CPR probably has no role in the warm zone, since the likelihood of successful outcome following cardiac arrest secondary to trauma is nearly zero. (The exceptions are arrest due to electrocution and toxic exposure, in which cases the supportive therapy of artificial ventilation can be therapeutic). On the other hand, hemorrhage control for an extremity wound might be lifesaving.
The "transit risk" is another one of the multiple factors which must be considered in TEMS decision-making. Transit risk consists of three components. The first is the amount of time it takes to move the casualty to a safer area. If it's a matter of a few seconds, then time is inconsequential. But, if it's a matter of minutes or tens of minutes, then some treatment in the warm zone, even considering the relative threat, might be prudent. Route of travel is the second component of transit risk. It may be necessary to travel through a hotter part of the warm zone, or even cross a hot zone, in order to extract the casualty to an area of greater safety. Under such circumstances, digging in and providing care may be more attractive than transporting immediately. Finally, the third component of transit risk is capability to deliver care during the move. While short transit times can make this component less important, the inability to deliver care during the extraction may require that certain stabilizing measures be performed before heading for safer haven. For example, if the airway is being maintained by jaw thrust and the four minute extraction will be performed using an improvised litter on the run, then taking the time and risk to insert a nasopharyngeal airway might be indicated, since it will not be possible to maintain a jaw thrust during transit.
Resist the temptation to think of the TEMS treatment zones as contiguous, concentric circles surrounding a crisis site. Indeed, the zones may be discontinuous. In the Texas Tower sniper incident, a germinal event for modern SWAT thinking, there were pockets of hot zone many blocks from the crisis site itself because the sniper had a clear line of fire from his high vantage point. On the other hand, due to the cover afforded by some neighboring buildings, there were pockets of cold zone close to the tower. The TEMS treatment zones may assume irregular shapes and may change rapidly during an incident.
The advantage of thinking in terms of hot, warm and cold treatment zones is that it provides a framework within which the EMT-T can prospectively and retrospectively analyze options under highly fluid conditions, when opportunities to gather a consensus and make collective judgements are minimal. It also simplifies a very complex problem by essentially eliminating the cold zone as a region where modified practice might be appropriate and reducing the complexity of decisions made in the hot zone.
In summary, TEMS decisions can be made in the context of three echelons; the hot zone, warm zone and cold zone. In the hot zone, there is a direct and immediate threat. Extraction is usually the only appropriate medical option. The warm zone is the area where a potential, but poorly defined and highly dynamic threat exists. Some warm zones may be hotter than others. In this zone, the benefits of medical intervention must be carefully weighed against the risks of operating in this zone. Modified scope and practice are most appropriate here. The cold zone is an area of relative safety and security where normal EMS practices can usually be applied. The Transit Risk must be evaluated when deciding to move from a hotter zone to a cooler zone. It consists of transit time, transit route and transit care or the capability to deliver essential care while transporting.