Learning Points
The purpose of this month's Clinical Skills column is to provide safe and effective best practice guidance for the use of haemostatic agents, or haemostats, in the pre-hospital environment. The topic of haemostats will be discussed in relation to what they are, how they work, as well as the when, where and how to use them for best effect. Haemostats themselves are straightforward to use and apply—the more interesting aspect is understanding when to use them.
Haemostatic agents
The concept of blood clotting and its benefits in preventing blood loss is well understood. When a patient haemorrhages severely, they lose the medium to transport oxygen around the body; and without oxygen, our cells die (Martini, 2006). With this in mind, it is important to understand and appreciate the value of a substance that rapidly prevents blood loss by creating a swift clotting process.
To understand haemostats, Celox©-type agents will be used as examples within this article, as they are commonly used in UK pre-hospital practice (Celox Medical, 2018). A haemostat is a collective group of substances that creates a rapid clotting process which does not follow the normal clotting cascade.
Celox is a chitosan-based agent (Pozza, 2011)—a substance derived from the shells of some crustaceans through chemical processing. This is one of the key elements that gives the haemostat its ability to function. When combined with blood, the haemostat forms a gel that acts as an artificial clot and this occurs much faster than the normal physiological process. Because this process works differently to the body's normal clotting cascade, it can be used on patients who may have conditions or be on medications that normally prevent effective clotting (Klokkevold et al, 1999; Pozza, 2011).
Background
Uncontrolled haemorrhage is one of the most common causes of mortality in patients who have suffered some form of blast or blunt/penetrating injury (Eastridge, 2012; Valdez et al, 2016). A tourniquet device could be used if the uncontrollable haemorrhage occurs on a peripheral limb (Pozza, 2011; Bennett, 2017). However, other areas such as the torso can prove challenging when managing an uncontrollable haemorrhage. In most modern assessments of patients, catastrophic haemorrhage is now considered a higher priority than the airway (Association of Ambulance Chief Executives (AACE) and Joint Royal Colleges of Ambulance Liaison Committee (JRCALC), 2016). Thankfully, catastrophic haemorrhage can almost always be managed effectively and with minimal training when using haemostatics (Grotenhuis, 2016).
Haemostatic agents are substances that come in many forms, such as gauzes, granules, patches or even syringe-based forms. The definition of haemostatic is ‘retarding or stopping bleeding’ and this is exactly what haemostats do (Harper Collins, 2018).
Haemostats create clots rapidly on contact with blood. This forms a strong and effective tamponade of haemorrhage at the point of injury (Pozza, 2011). Haemostats have been battle-tested (quite literally) for over a decade, and have been developed and researched further to ensure that effective and safe forms are available for use (Bennett, 2017). Haemostats have become more commonly used and incorporated into the civilian sector successfully (Travers et al, 2016).
In the early days of haemostatic development and use, some side-effects were noted. One example was that when combined with blood, it created an exothermic or heat-generating reaction. This complicated some injuries by adding burns to the area, which created an added challenge. These forms of haemostats are no longer manufactured and this should no longer be a concern when making the decision to use a haemostat (Bennett, 2017).
Types of haemostats
Haemostats have been developed to assist in the management of many different types of injuries and subsequent major haemorrhages (Kheriabadi, 2010). The most commonly encountered forms will be discussed in this article.
The original form of haemostatic agent is the granular or powder form found in tear-open sachets, that are then poured into wounds or bags that are put directly into the wound (see Figure 1). Also in Figure 1 is a newer addition—a syringe type which holds the compound inside and is used for smaller deep-penetrating injuries. When these are combined with pressure, they form a clot. Another type is a gauze impregnated with a haemostatic agent; these are more commonly and widely used (Figure 2), though there are variations which work in a similar manner.
Decision-making
Haemostats are extremely useful adjuncts in the management of haemorrhage. As not all locations are accessible to tourniquet application, there is almost no limit to haemostats (Pozza, 2011). An example of this could be if a patient had suffered a penetrating injury to the groin, severing blood vessels. As direct pressure would be difficult in a location such as this, a haemostat could be the only effective adjunct a pre-hospital practitioner has.
Whereas tourniquet use is directly indicated for catastrophic haemorrhage, haemostatics can be safely used for a much larger variety of situations (Bennett, 2017). If the patient has a wound that is bleeding, technically a haemostat can be used to assist in management of the bleeding. This should be undertaken with logical and clinical discretion as it would be wasteful to use this on every cut and injury encountered. Rather, it should be used for wounds that are uncontrollable and/or difficult to manage.
During the decision-making process, the advantages and patient benefit grained from using haemostats should be explored to reach an appropriate decision on its use. As was briefly mentioned, haemostatic substances do not use the normal clotting cascade and it is therefore safe and effective for use in patients who have clotting disorders, or who are taking medications classed as anticoagulants, as well as in hypothermic patients (Klokkevold et al, 1999; Kheriabadi, 2010). There are many other abnormalities which could occur to alter the normal clotting process, as haemostats generally work around the normal clotting cascade. It is an effective adjunct when approaching a range of injures or patients with comorbidities (Klokkevold et al, 1999; Kheriabadi, 2010).
Approach and use
Once the decision to use a haemostatic has been made, there are different methods of application. Depending on the number of practitioners available, the approach can be performed as a two-person team or as an individual. When referring to a ‘two person’ or ‘team’, it designates that a person is already on scene but without a haemostat.
The generalised approach is to initially apply direct pressure on the wound, followed by a haemostatic dressing or pressure bandage. This would then be followed by a tourniquet (if indicated) (National Association of Emergency Medical Technicians (NAEMT), 2018). This is under ideal circumstances and with a second practitioner present.
If it is a single practitioner approach, the first attempt of management should be to apply the haemostat as soon as possible with pressure applied as well as securing dressings if required. Following this, a tourniquet could be applied if required (NAEMT, 2018). Pressure post-application of the haemostat is essential for effective haemorrhage control.
After the initial haemostat dressing, additional dressings can be haemostats or non-haemostats, as long as the function of pressure and dressing the wound is achieved.
Method of application
It is worth noting that some versions of haemostats can effectively clot within 1 minute of pressure. The remainder have the general recommendation for at least 3 minutes of direct pressure. To avoid confusion, advice in this guideline will remain as 3 minutes. If the specific type is for 1 minute, that would be adequate but if unsure, use a minimum of 3 minutes of effective direct pressure.
All of these patients should be monitored for rebleeding and transported rapidly where appropriate (National Institute for Health and Care Excellence (NICE), 2017).
Important points
It is worth noting the limitations of haemostatics. They are contraindicated in any ocular injury and not meant for consumption. Although chitosan is manufactured from shells, including prawn shells, it is refined thoroughly. According to Celox Medical, it does not have any risk that can cause an allergic reaction and is safe to use on patients with shellfish allergies.
A haemostat is an effective tool in the arsenal of emergency pre-hospital medicine and should not only be reserved for mass casualty scenarios. However, it must still be used with a full management plan to ensure the best possible outcome for a patient (Butler et al, 2007; Bennett, 2017).
For the effective use of any form of haemostat, training and familiarisation with the equipment should occur. This is not because the haemostats are difficult to use; but as they are not commonly employed, their effective usage may well be forgotten in the heat of the moment. Become familiar with the product you carry and remember the benefits and advantages of haemostats.