This module discusses casualty monitoring Tactical Field Care (TFC) setting, emphasizing your role as a Combat Medic. Casualty monitoring takes place at a few points during the MARCH sequence and tactical trauma assessment, both through observations and formal assessments.
This module discusses casualty monitoring Tactical Field Care (TFC) setting, emphasizing your role as a Combat Medic.
All Service Member and Combat Lifesaver training educates non-medical personnel about a few monitoring techniques, like assessing peripheral pulses and respiratory rates, but as a Combat Medic, you will have additional knowledge and equipment that allows you to expand casualty monitoring during TFC and in preparation for transitioning casualty care to the next echelon of care.
There are two cognitive and five performance enabling learning objectives in this module.
First, we’ll cover the methods for assessing the casualty’s level of consciousness, pulses, and respiratory rate. Afterward, techniques for monitoring trends in vital signs using both manual assessments and electronic monitoring will be reviewed.
Finally, you will demonstrate assessments of the level of consciousness, pulses, respiratory rates, and then demonstrate the use of pulse oximetry, electronic vital sign monitors, and end-tidal CO2 measurements using colorimetric devices.
Casualty monitoring takes place at a few points during the MARCH sequence and tactical trauma assessment, both through observations and formal assessments.
The casualty’s level of consciousness is important from the onset of any assessment and should be informally assessed by the casualty’s response to and participation in their treatment plan, or formally assessed if the casualty is not alert; as it can impact clinical decisions at several different stages. Additionally, the respiratory rate may help determine whether a casualty is in respiratory distress during the “R” in MARCH, potentially informing the need for treatment. Likewise, during the “C” in MARCH, the presence of pulses and the heart rate are part of the determination of shock (along with level of consciousness) and influence decisions on fluid resuscitation.
Reassessment is a continuous process in casualty management, and monitoring should not be limited to specific steps in treatment algorithms but be part of the ongoing care for the casualty.
The AVPU method, or Alert, Verbally responsive, Pain responsive, or Unresponsive, provides responders the information they need to make decisions. There are more advanced measures of response, like the Glasgow Coma Scale or the Grady Coma Scale, but in TFC they seldom provide additional information to guide treatments, and the AVPU method is preferred.
Although a formal assessment may be necessary, sometimes the casualty’s response to the tactical trauma assessment and treatments provide their status without taking time to formally check each step. For example, if they are conversing with the responders and engaging in their care, they are alert. And no formal assessment is needed before documenting that in their medical record. Likewise, if they are unconscious and not reacting to wounds and treatments known to be painful, they are unresponsive. Time permitting, a formal assessment may be done, but if an important treatment might be delayed, it may not be necessary in those cases.
Formally assessing the level of consciousness is a relatively straightforward process. It involves three basic steps:
AVPU may be difficult to assess depending on the environment and the mission situation.
This video will highlight the procedure of assessing the level of consciousness of a casualty.
Assessing pulses is one of the most important tools available to determine a casualty’s status, and whether they are deteriorating or responding to treatments. Pulses may be difficult to assess depending on the environment and the mission situation. Pulses can be checked at multiple different sites, and Combat Medics should be proficient at finding pulses at each of them, as the tactical and clinical situation may dictate that one site is most appropriate for the situation. If not done earlier as part of massive hemorrhage control, pulses should be checked during the circulation assessment, or “C” of MARCH, preferably using the radial arteries, if possible.
The 5 pulse sites used in TFC are the carotids, the radials, the femoral, the dorsalis pedis, and the posterior tibial.
Estimating perfusion (or blood pressure) in a field setting often relies on determining palpable pulses. Published reports on blood pressure estimates from palpating radial pulses among the civilian trauma population are limited and lack consensus. One study reported that 83% of subjects with a palpable radial pulse had an SBP < 80 mmHg, whereas another study found that 100% of its subjects with a palpable radial pulse had an SBP > 80 mmHg. So, the presence or absence of radial pulses is used as a sign of hypotension for determining shock and recommending fluid resuscitation.
That said, a study published in 2020 from the DoD Trauma Registry indicated that although mean systolic blood pressure was associated with radial pulse quality, characterization of the radial pulse was not always a reliable indicator of hypotension. They recommended assessing the blood pressure if tactically feasible, as some casualties with hypotension still had radial pulses.
ТAlso, keep in mind that the pulse rate can help estimate a casualty’s status and provide information about changes in their status, regardless of their blood pressure. The heart rate will increase prior to the blood pressure dropping in the normal hypovolemic response.
Landmarks for each pulse site are well-described, but individual anatomy varies. It is important to practice assessing pulses on a variety of people as you go through your training, as this will help you develop techniques for discovering pulses in those casualties who have anatomical variants. Several of those techniques are described in the detailed skill instructions that accompany this module.
Remember to press firmly at the pulse site but also avoid causing harm to the casualty by pressing too hard. This is more of an issue with the carotid arteries, where you can cause lightheadedness with excessive pressure, checking femoral pulses in the presence of a suspected pelvic fracture, and when checking pulses on injured extremities.
This video will highlight how to assess radial pulses.
This video will highlight how to assess carotid pulses.
This video will highlight how to assess dorsalis pedis pulses.
This video will highlight how to assess posterior tibial pulses.
This video will highlight how to assess femoral pulses.
A thorough respiratory assessment consists of inspection, palpation, percussion, and auscultation, but in the field, the extraneous noises and tactical limitations make percussion and auscultation very difficult. As a result, inspection and palpation, looking at the respiratory rate and the respiratory effort, are the main tools the Combat Medic will be able to use.
In the modules on airway and respiration, the concept of look, listen, and feel was discussed – looking at the rise and fall of the chest as well as the effort to breath, listening for the sounds of breathing (or when possible, auscultating), and feeling the breath against your cheek or the rise of the chest.
When assessing the rate, it is important to remember that body armor, ambient noises, and other tactical or environmental factors can make it very hard to see, hear, or feel the casualty’s breaths, especially if their effort is reduced, and you may need to reposition yourself or the casualty. Also, be sure to measure for at least 15 seconds, as slower rates often provide misleading information if measured for short time periods.
In addition, assess the respiratory effort. As discussed in the respiration module, basic signs and symptoms of respiratory distress include tripod respirations, orthopnea, nasal flaring, and retractions or any abnormal breath sounds. These should also be documented along with the respiratory rate. Respirations may be difficult to assess depending on the environment and the mission situation.
The purpose of pulse oximetry is to measure the percent of total hemoglobin in peripheral arterial blood that is saturated with oxygen (SpO2). Pulse oximeters are now commonly included in the medical kits carried by Combat Medics and are a useful adjunct to physical examination skills during clinical assessments. Physical findings like cyanosis and pallor are very difficult to assess in low-light operations and hypoxemia can easily be missed.
Normal pulse oximetry, or pulse ox, values are in the high 90s, unless at altitude, in which case they may be significantly lower. For example, healthy person at 12,000 feet may have a pulse ox in the high 80s. This is an important point to remember during aeromedical evacuations when cabin altitudes may trigger a decrease in the pulse ox readings. Low saturation levels and trends to lower saturations can be indicative of respiratory compromise and should trigger further assessment to rule out life-threatening conditions.
There are several factors that can affect the pulse oximetry readings. Lowered readings can be caused by shock (where the poor perfusion affects the signal and causes a low reading) and cold temperatures (which cause peripheral vasoconstriction with a similar drop in perfusion). On the other hand, carboxyhemoglobin (seen in carbon monoxide poisoning) can cause a falsely elevated reading. And other conditions can interfere with the readings by altering the perceived intensity of the light signal, like very well-lit environments, nail polish, some skin pigmentations, and motion artifact.
Pulse ox monitoring should be initiated in casualties who are unconscious or who have injuries associated with impaired oxygenation (like blast injuries, chest contusion, and penetrating injuries of the chest). It should also be used to monitor casualties who have TBI, in order to ensure that their oxygen saturations remain above 90%, as hypoxemia will worsen their clinical outcomes.
Keep in mind that saturation levels may not signal impending shock, as good hemoglobin oxygen saturations may be seen in casualties shortly before they go into hypovolemic shock. Also, if a casualty has obvious signs of airway obstruction, tension pneumothorax, or hemorrhage, their treatment should not be delayed to establish pulse oximetry.
This video will highlight how to use a pulse oximeter.
As electronic monitoring devices have become lighter and smaller, they have been introduced further forward on the battlefield. They are commonly seen in Battle Aid Stations, and in evacuation platforms, but may also be found elsewhere in the tactical environment.
There isn’t a specific monitoring device that is universally utilized by all medics. The Patient Movement Items program has standardized an approach, but this applies to the field hospitals, fixed facilities, and the medical evacuation system, and does not mandate a certain monitor type be adopted for Tactical Field Care. That said, all monitors have a few basic capabilities that every Combat Medic should know about.
The first is their cardiac monitoring capability. This involves application of monitor leads directly on the casualty’s skin, with manufacturer guidelines identifying the electrode locations and device operation. Although the primary function of this in TFC is to evaluate the heart rate, if there are irregularities to the rhythm this might also indicate a need for further evaluation by an advanced provider.
Another feature is an integrated pulse oximeter. The application of the probe is the same as a portable pulse ox, usually using a finger, or perhaps a toe. And the functionality and limitations just discussed all apply, as well.
The automated blood pressure capability allows the responder to place a cuff on the casualty and set a timer for serial pressure measurements without having to manually assess the pressure each time. Of course, a new assessment can be initiated at any time through a simple request. The machine also stores the results of each pressure reading, in case the Combat Medic has been dedicated to other casualty care and was unable to document the findings after each cycle.
Some monitors will have additional capabilities for more advanced monitoring, like end-tidal carbon dioxide or temperature monitors; but these are not standardly used in the TFC setting, and often require more advanced training.
Although the monitors do run on batteries, the battery life is not always optimal for the situation. So, when possible, keep the monitor plugged into an electrical source during use and between uses.
Also, since every monitor is a little different than the next, make sure that you familiarize yourself with the monitors you are likely to encounter when deployed and use that type of monitor in your routine training at home station.
This video will highlight how to use an electronic monitor.
End-tidal carbon dioxide (CO2) colorimetric devices provide a qualitative measure of the CO2 being exhaled to help confirm that an advanced airway is properly positioned or that a casualty is being properly ventilated.
The colorimetric detector produces a color change as carbon dioxide flows through a litmus paper film in the airway circuit. These detectors are very simple, light, and portable devices that do not require power and are adaptable to the TFC environment.
Colorimetric end-tidal CO2 devices are relatively easy to use. When removed from its package, the paper color should match the color in the “check” area of the color chart that surrounds it. A tapered female end fits over the standard airway tube (endotracheal tube, tracheostomy tube, or extraglottic airway). The male end is the same standardized size as the airway to allow for attachment of a bag valve mask or other ventilation asset. When placed, the device is “in line” and the air will pass through it during both inhalation and exhalation. It may take a few breaths to clear the line of any CO2 build-up not related to ventilations, so don’t assess the color change until 6 breaths have occurred. Then, check the paper sensor color against the color chart that surrounds it. The absence of color change indicates an improperly placed airway, which should be repositioned and reassessed, while a color change indicates proper placement, after which it should be monitored to ensure nothing changes.
Of note, the detector paper in colorimetric units is particularly sensitive to fluids, and fluids such as vomitus, frothy secretions from a casualty with traumatic pulmonary injuries, sputum, or moisture can render CO2 detectors ineffective. Also, a false negative CO2 reading may occur in cases of cardiac arrest when there is no cardiopulmonary circulation to carry CO2 to the alveoli and ultimately to the detector. Replace colorimetric devices after two hours, unless using a pull-tab device that is good for 24 hours, as the litmus reaction may diminish and provide false readings.
Ensure that the manufacturer's guidelines are followed when reviewing the color-coded portion on the device.
Each set of vital signs and level of consciousness assessment provides a snapshot of the casualty’s status at the time they are taken. Often, that is enough information to help the responder make decisions on casualty care and when interventions are appropriate. But sometimes an isolated set of vital signs may look reasonable and not trigger any action, yet represent a change from baseline that could alter the treatment plan if the responding medic was aware of the change.
Examples of this would include an increasing heart rate over time when serial measurements are available. This is often indicative of persistent blood loss and would normally lead to a reassessment of all hemorrhage control measures and a search for sources of occult blood loss. The same could be said for a decreasing level of consciousness over time, which might represent worsening shock, or progressive damage from brain injuries.
Trends in vital signs provide insight into the casualty’s clinical course that helps the responder identify the need for interventions or assessments earlier than would happen with a single set of vital signs. Not all trends are signs of deterioration, though. With fluid resuscitation or other interventions, vital signs often trend towards normal when responding properly.
When caring for multiple casualties, it is very difficult to remember the vital signs of each casualty and the changes that occur over time. This is why it is so important to document all of these findings on the DD Form 1380 TCCC Casualty Card after each assessment.
Another time when trends in vital signs are very important is during the transition of casualty care from the Combat Medic to the medical evacuation team. This is the first time they have seen the casualty, and objectively demonstrating how they progressed (or regressed) during the TFC treatment phase helps the evacuation team know how to respond to in-transit changes.
Even if your casualty appears stable and is being evacuated routinely, continuously reassess their status and document their vital signs, looking for any trends that might change your treatment plan.
1 PDF Pulse Assessments Skills Card
2 PDF End-Tidal CO2 Colorimeter Skills Card
During this module, we went over the basics of monitoring casualties in the Tactical Field Care phase.
Assessing the level of consciousness, identifying pulses and determining the respiratory rate and effort, as well as using pulse oximetry were all reviewed. Additionally, the potential use of electronic monitoring was introduced. The importance of continuous reassessment and monitoring trends in vital signs were also considered.
Afterward, the procedures for assessing the AVPU status of a casualty, checking the various pulses, and measuring the respiratory rate were all demonstrated. Also, the use of electronics monitors and the application and assessment of pulse oximetry and end-tidal CO2 colorimeters were demonstrated.
To close out this module, check your learning with the questions below (answers under the image).
Answers
What does AVPU stand for?
The AVPU method, or Alert, Verbally responsive, Pain responsive, or Unresponsive, provides responders the information they need to make decisions.
Why do the TCCC Guidelines recommend checking a radial pulse?
The presence or absence of radial pulses is used as a sign of hypotension for determining shock and recommending fluid resuscitation.
What is the importance of following trends in vital signs?
Trends in vital signs provide insight into the casualty’s clinical course that help the responder identify the need for interventions or assessments earlier than would happen with a single set of vital signs.
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