Many emergency medical services (EMS) providers know the signs and symptoms of stroke and how to treat stroke appropriately. However, by understanding how to manage stroke patients in the hospital, pre-hospital providers can help facilitate the overall management of the patient, similar to how obtaining a 12-lead ECG or lactate value can speed up overall patient care. By understanding which procedures are usually initiated in the emergency room, EMS providers can better prepare patients for the care they will receive when they arrive at the hospital. An example of this is the location of the IV and the size of the catheter.
No. 20 IV is usually the standard used by EMS for general adult medical patients, and some providers are taught to "use the smallest catheter possible"? 1 In the elderly, the aging process and long-term use of certain drugs due to the decline in muscle mass and thinning of the skin in the elderly. Usually larger IV gauges are used for fluid rehydration, mainly for trauma patients. The purpose of this article is to 1) allow EMS providers to better understand in-hospital stroke care, especially CT scans, and 2) suggest that large venous catheters and more proximal vein placement may also promote overall stroke patient care.
To briefly review, when the blood flow to the part of the brain is interrupted due to a ruptured or occluded blood vessel, the patient experiences a stroke, which can lead to a hemorrhagic or ischemic stroke. A hemorrhagic stroke occurs when a blood vessel ruptures and allows blood to seep into the brain. An ischemic stroke occurs when the blood vessels that carry blood to the brain are blocked or restricted by clots or severely narrowed arteries. Ischemic stroke accounts for about 87% of all strokes. 2 Accurate and timely assessment of these patients is very important, because patients with diseases other than stroke may have similar clinical manifestations, and the results of patients who actually suffer from stroke may depend on time to a large extent.
Outside the hospital, the Cincinnati Stroke Scale or Los Angeles Exercise Scale (LAMS) can be used to help assess potential stroke patients. If a stroke is suspected, pre-hospital care usually includes ABC, HOB positioning at 30 degrees, checking blood sugar, oxygen, venous access, heart monitoring, and receiving notification from the hospital, depending on the level of the provider. After arriving at the emergency department, one of the procedures usually ordered is imaging, which plays a key role in helping to rule out conditions with stroke-like manifestations. If a stroke is confirmed, the treatment depends on the type of stroke. A CT scan of the head is usually one of the first tests performed.
Because immediate stroke treatment can help reduce mortality and/or disability by restoring blood flow, and CT scans are relatively quick and easily available in most cases, it has become a common diagnostic test. For pre-hospital providers, a better understanding of hospital stroke management, including CT scans, can help identify steps that can facilitate emergency department patient care and speed up the overall management of stroke patients.
When the patient arrives in the emergency room and signs and symptoms suggesting a possible stroke appear, imaging is essential for making a correct diagnosis and immediate treatment. Usually, the first imaging test for such patients is a dry CT scan of the head. CT scans use X-rays, such as those commonly used to detect fractures. However, CT scanners use X-rays in a more advanced way to produce cross-sectional images that look like "slices"? Brain, or three-dimensional image. Providers may hear hospital staff refer to CT as dry or wet. These terms generally describe whether the patient will receive IV contrast.
In dry or non-enhanced scans, no contrast agent is injected into the patient. A dry scan is usually performed as soon as possible after reaching the ED, because CT scans are very useful for identifying hemorrhagic lesions and signs of ischemia in infarction. Dry head CT can determine whether the patient is suitable for tPA.
After the dry head is completed, or if the patient cannot receive tPA, CTA (computed tomography angiography) can be performed to determine whether mechanical thrombus removal is required. CTA is an example of a wet scan, which involves injecting a contrast agent into a blood vessel before the scan. It is in this case that pre-hospital care can help speed up treatment.
Is it most effective to use a device called a "power injector" for contrast delivery? It can be programmed to deliver a specific amount of contrast agent at a specific flow rate. For patients with ischemic stroke, CTA images can identify which blood vessels are blocked, and this information can help decide how to treat the patient. In a hemorrhagic stroke, CTA can show an aneurysm or other types of vascular problems that cause bleeding.
In some institutions, patients suspected of having an ischemic stroke may also undergo a third type of CT scan, called CT perfusion imaging or CTP. CTP involves a second injection of the same contrast agent as CTA. Unlike CTA, which creates pictures of the large arteries that carry blood to different areas of the brain, CTP measures blood flow through microscopic blood vessels that are small enough for the brain to extract oxygen and other nutrients from them. This information can be used to decide how to best treat patients with ischemic stroke.
CTA and CTP are performed using the same type of scanner used to generate traditional CT images, and various types of images are usually acquired together as part of the same examination. Patients receiving CTA or CTP usually experience a brief warmth or tingling sensation when injecting the contrast agent, but most people do not find this unpleasant sensation and will disappear after a few seconds. In addition, traditional dry head CT can be performed on any patient, but if they receive a contrast agent, consent is required. Some patients are allergic to the intravenous dyes required for CTA or CTP, and the patient must have adequately functioning kidneys.
There is a considerable amount of literature on fluid resuscitation, generally on trauma patients, usually mentioning the use of two large-caliber catheters. However, if pre-hospital providers can predict the in-hospital care of stroke patients, just as they can use injury mechanisms to predict injury patterns, the use of large-caliber IV may also be beneficial for stroke patients.
The venous CT contrast is as clear as water and has similar consistency. An electric syringe is usually used for injection, but it can also be injected manually. Usually, 75 ml to 150 ml of contrast agent is used depending on the patient's age, weight, and body area being scanned.
Peripheral intravenous injection of the upper and lower extremities is usually possible for dynamic injection, except for pediatric patients less than 10 kg. Forearm or hand veins are often used in EMS and can be used to inject contrast agents, but they are not the first choice of radiographers. Due to its small size, hand veins may not be suitable for large-caliber intravenous catheters suitable for high injection flow rate (4 mL/sec) and high iodine concentration contrast media. (The electric syringe contains 125 mL non-ionic contrast media [300 mg iodine per ml ] And 50 mL saline solution. 3 Injecting the contrast agent through a site farther than the anterior cubital vein may be done at a slower speed and increase the dispersion of the contrast agent. Compared with the anterior elbow vein injection, the forearm intravenous injection of contrast agent The enhancement speed is slower. The full vascular delineation of stroke patients requires a high contrast medium flow rate. Therefore, the use of a catheter that can inject iodine contrast medium at a high injection speed with a power supply requires a syringe for intravenous access. After the contrast medium is injected, it passes through the right heart, pulmonary circulation, The left heart reaches the central arterial system. Its circulation is clearly regulated by the cardiovascular system. The contrast is rapidly redistributed from the vascular space to the interstitial space of the organ. Since the iodinated contrast agent is composed of relatively small molecules that are highly diffused, the contrast agent Transmission is mainly determined by flow. Therefore, the delivery of the contrast agent through the circulatory system to the head is critical to the effectiveness of the contrast agent. When the contrast agent circulates in the body, it will be diluted by the blood and dispersed when it passes through the circulatory system. The greater the distance from the injection site, the stronger the dilution effect. For example, the blood in the cerebral circulation returns to the right heart and recirculates faster than the blood in the portal circulation.
The speed and volume of contrast injection will be affected by the size of the catheter used and the injection site. The first choice is not smaller than the No. 20 catheter placed in the anterior cubital vein, and the No. 18 catheter will further enhance the contrast injection. Many times, outside the hospital, larger intravenous catheters and anterior cubital veins are reserved for rehydration for trauma patients. However, the use of both is beneficial to the diagnosis and subsequent treatment of stroke patients.
By understanding and better understanding what care a stroke patient will receive in the emergency department, pre-hospital providers can adjust or customize their care to facilitate and speed up the global management of stroke patients and may affect their recovery and/or survival. Perhaps the best example is understanding the role of imaging in stroke management, what type of imaging the stroke patient will receive, and how the patient will prepare for it before arriving at the hospital.