JEMS Clinical Review Feature
This clinical review feature article is presented in conjunction with the Department of Emergency Medicine Education at the University of Texas Southwestern Medical Center, Dallas.
>> Describe uses of standard prehospital monitors when assessing a patient who’s entrapped with little access.
>> List assessment findings that indicate potential injuries and review treatment options.
Crush syndrome: The result of pressure trauma to muscles that exerts prolonged continuous pressure causing tissue disintegration and the release of myoglobin.
Hyperkalemia: The condition of having too much potassium (K+) in the blood.
P wave: A component of the ECG that corresponds to atrial depolarization.
P-R interval: A measurement of two ECG components that indicate the length of time of conduction through the AV node and the intermodal pathways; QRS-components of the ECG that correspond to depolarization of the ventricle.
T wave: A component of the ECG that corresponds to vetricular repolarization.
Thermal imaging units: A device that creates a visual representation of temperature differences in a given area.
Patient assessment begins at the time of dispatch, and EMS providers routinely use advanced information received about the situation. While responding, they begin to think of what illness or injury the patient may have and think through their assessment priorities. When patients become trapped as a result of building collapses, cave-ins and other incidents that render the patient inaccessible, EMS crews face the additional challenges of gaining access and information by using equipment they initally have available to them.
Your crew has been dispatched to a house that was having its footings shored as a result of some earth slippage. The reporting party told the dispatch center he witnessed the house shift and then collapse onto the crawl space. It’s unknown if anyone was under the house during the collapse, but a workman’s truck was parked in the driveway. The first on-scene fire crew has identified several small void spaces in which a patient might be present and begin calling out to try to locate trapped individuals.
How else can you locate a potential patient under the floor? What other tools do you have that can be used until rescue units arrive? Many fire services carry thermal imaging units that can scan the area for body heat emissions. Some agencies also carry carbon dioxide (CO2) sensors that work well in detecting patients in small spaces. Cardiac monitor/defibrillators also have the ability to check for the presence of CO2, which is a strong indication that someone is breathing in the confined space.
In the event that multiple patients are trapped at the same incident, you may need to perform triage on patients you can’t see or touch. Gaining access to these patients could require a significant time commitment and specialized rescue resources that may not be readily available. So using thermal imaging and/or CO2 sensors to probe void spaces for signs of life can help you effectively utilize rescue resources.
Once you locate a trapped patient, begin your primary airway, breathing and circulation survey. Any patient who can speak or tap on command has an airway, is breathing and has some circulation. Even if you don’t have access to the patient, you can gather additional assessment information by asking the patient questions about their situation. Ask one question at a time and wait for a response. If the patient is only able to communicate by tapping or grunting, you need to ask “yes” or “no” questions.
Keep in mind that the scene may be very noisy, especially once rescue operations begin or if more than one rescue is being attempted. This can hamper your ability to hear your patient once you’ve made contact. With coordination between the other resources at the scene, you may need to establish brief “all quiet” periods during which all work and talking stops in order to communicate with and monitor your patient.
In the collapse of the shored-up house, a small access hole has been made, and you can now see the patient’s sternum. Officials fear the building is unstable and think further shoring needs to be done before cutting a larger access hole.
What can we learn from having access to their sternum? You can check for capillary refill, skin color, breath movement, and heart and breath sounds. You can also use your pulse oximeter to remotely monitor their oxygen saturation via a disposable sensor placed directly on the sternum. This allows the light wave to bounce off the patient’s sternum and measure their pulse oximetry.
With some disposable sensors, the space between the “transmit” and “receive” sensor may need to be filled by “tenting” the gap between the two so they’re closer together during application. This can be tried on any flat bone area, such as the forehead or tibia. But remember that the sensor won’t likely get a signal in patients with poor circulation.
This assessment information will assist you in figuring out what’s going on with the trapped patient. Watching their sternum move will give you a respiratory rate, and listening to the breath sounds may reveal pulmonary edema or wheezes.
If the pulse oximeter is able to get a reading, you’ll get a heart rate and be able to see the oxygen saturation, which provides a good indication of respiratory status. Capillary refill of less than two seconds is a good sign; longer than that can indicate hypothermia or hypovolemia. Pale skin color may also indicate hypothermia or hypovolemia.1,2 Cyanosis indicates significant hypoxia.
You’ve just assessed airway, breathing and circulation—all from a sternum. Then you gain access to a hand. What can you add to your assessment?
If the trapped patient is unable to speak, they can squeeze the provider’s finger once to indicate “yes” and twice for “no.” Asking the patient if they can feel the provider’s touch will also present neurologic findings. You should now move the pulse oximeter to the patient’s finger to obtain a better signal.
Attach an ECG electrode to the hand and sternum to get an early ECG tracing. You must have two points of contact, with the heart somewhere in between them, to get a monitor tracing. A hand and a foot, two hands or a shoulder and a hip are all combinations that will work. When using a four-lead cable set, you’ll often need to connect all four leads for the monitor to work, so it’s easiest to keep the arm leads and foot leads together.
Keep in mind that if more than one patient is trapped together, the hand and the sternum that you have access to may not belong to the same person. You could differentiate patients by comparing the hand heart rates to the sternum rates you obtain with the pulse oximeter. And, be aware that, if two entrapped patients have bare skin touching, you may detect two ECG rhythms superimposed on the strip.
When assessing the ECG, look for dysrhythmias that can be caused by acidosis, electrolyte imbalance or cardiac contusion. Flat P waves with a widening QRS and peaked T waves may indicate elevated potassium levels that are a result of crush syndrome.
Start an IV or intraosseous access to administer normal saline and draw a blood sample. Point-of-care testing only requires a 1 cc blood sample to run multiple tests. There are 1 cc heparinized syringes that will preserve your blood sample longer than a regular plastic syringe.3 Use the blood sample to check a glucose level. If you have point-of-care testing equipment, verify such chemistry levels as potassium. If potassium levels are high, you know you’re dealing with a crush syndrome patient who will need special care and preparation before extrication.
Most ALS crews carry medications to pre-treat a crush injury patient. Depending on the patient’s condition, treatment may include large IV fluid boluses, continuous nebulized albuterol, IV calcium chloride or calcium gluconate, as well as IV sodium bicarbonate. Work with your medical director to establish a treatment protocol for crush injuries.
If the test results show that the patient’s hemoglobin and hematocrit are low due to hypovolemia from bleeding, or you suspect it from your assessment, make arrangements to have blood ready for a transfusion or surgery. In a prolonged entrapment setting, a blood sample that shows elevated hemoglobin and hematocrit percentages is an indication of hemoconcentration due to dehydration and should prompt the administration of IV and/or oral hydration.4
Now, can you access the wrist or ankle? If so, apply a non-invasive blood-pressure (NIBP) cuff. You may need a pediatric-sized cuff.5 If you don’t have an NIBP, consider palpating the pressure. If you’re using a manual cuff and stethoscope to monitor blood pressures during a prolonged extrication, you can reach in and tape the stethoscope bell over the area where you can feel and hear a pulse. This will make taking serial blood pressures quicker because you won’t have to reposition the stethoscope each time.
You can now see the patient’s face.
Check pupils, assess airway and administer oxygen. If waveform capnography is available, a combination of nasal cannula and an end-tidal CO2 (EtCO2) filter line can be applied. This allows you to assess and monitor the patient’s respiratory rate and ventilatory status.
Although capnography is a direct measurement of lung ventilation, it also indirectly measures metabolism and circulation. For example, an increased metabolism will increase the production of CO2, thus increasing the EtCO2. A decrease in cardiac output will lower the delivery of CO2 to the lungs, thereby decreasing the EtCO2.
EtCO2 monitoring can also provide an early warning sign of shock. A patient with a sudden drop in cardiac output will show a drop in EtCO2 without a change in respiratory rate. This has implications for trauma patients, cardiac patients and any patient at risk for shock.
Waveform capnography is becoming the standard of care for endotracheal (ET) tube confirmation and may be your only clue that your tube is in the trachea if you only have access to the patient’s head. If the patient needs an advanced airway, consider using such supraglottic devices as the King LT airway, Combitube or laryngeal mask airway, because it might be difficult to align the airway for ET intubation in a confined space. Don’t forget that waveform capnography will also work to monitor placement of supraglottic devices.
In some confined space situations, the patient or a rescuer may be trapped and injured while suspended in a harness. For example, your patient may be a utility worker in an electrical vault or an industrial worker cleaning a tank interior. If the patient is suspended vertically in a head-up position and unable to move, they can quickly present with suspension trauma.
Suspension trauma, also known as orthostatic incompetence, can advance within minutes if a person is unable to get their legs above their hips or actively use their leg muscles.
The heart isn’t capable of pumping blood out of the lower extremities against gravity on its own. It requires the help of skeletal muscle contraction and valves in the veins of the lower extremities to move blood back out of the legs. Therefore, patients with suspension trauma usually present with light-headedness, near syncope, shortness of breath and tachycardia within five minutes of being immobile, and typically lose consciousness within 30 minutes. Because they’re still suspended in a head-up posture, the body isn’t able to correct the problem by falling to a horizontal position, as with typical syncope.
In addition to venous pooling in the legs, the pressure caused by the loops of the patient’s harness can contribute to the development of rhabdomyolysis and a crush injury.
It’s critical you recognize this potential and be prepared to pre-treat the patient before they’re completely released from the harness. It’s also important that a conscious patient who’s released from immobile suspension be kept in a seated position for approximately 30 minutes, if possible, to slow the equalization of static blood to the right ventricle.
As a rescuer, it’s critical that you’re aware of your own risk of suspension trauma when working in a harness. Keep yourself from becoming a patient by following the safety recommendations at jems.com/journal.
Providers should be resourceful in their patient assessment by using all the tools available. Patient monitoring in this challenging situation calls for creativity and a thorough understanding of all the tools at their disposal because non-traditional use of monitoring equipment may yield valuable information that can formulate treatment plans.6,7 Most importantly, remember that early, aggressive treatment of hyperkalemia is necessary for survival of “crush syndrome” patients. Look for ECG changes of peaked T waves, flattened or absent P waves, prolonged P-R interval, prolonged QRS a “sine-wave” pattern resembling slow ventricular tachycardia and other arrhythmias.
Much of the assessment of confined space patients can be conducted remotely and with limited patient access. Remember the tips presented here and all the patient assessment lessons you’ve learned throughout your career. Put them together into an innovative package when confronted with any hard-to-reach patient.6,7 JEMS
This article originally appeared in November 2010 JEMS as “Restricted Access: How to treat patients in confined spaces.”