Med-Surg - Nervous System, part 5: Nervous System Diagnostic Tests
by Cathy Parkes October 27, 2021 Updated: April 24, 2022 5 min read
Hi, I'm Cathy, with Level Up RN. In this video, I will be covering diagnostic tests associated with the nervous system. Specifically, I will be talking about a cerebral angiogram, and the EEG, intracranial monitoring in lumbar puncture, as well as an MRI. At the end of the video, I'm going to give you guys a little quiz to test your knowledge of some of the key facts I'll be covering in this video. So definitely stay tuned for that. And if you have our Level Up RN medical-surgical flashcards, definitely pull those out so you can follow along with me.
First up, we have a cerebral angiogram, which allows for visualization of the cerebral blood vessels to check for blockages or other abnormalities.
So during this procedure, a catheter is placed in the artery, usually at the femoral artery there at the groin, and is threaded up through the blood vessels to the brain.
So in terms of nursing care, pre-procedure, you want to make sure your patient has been NPO for four to six hours or per facility policy. You want to check for an allergy to contrast dye, which is definitely used in this procedure.
And you also want to assess for kidney function by assessing the patient's creatinine and the BUN levels. So if the patient has impaired kidney function, then this will impact their ability to excrete that contrast dye, which could be a problem for their kidneys.
In addition, you want to assess and mark the pulses distal to where the insertion site will be so that you can easily check those pulses after the procedure, after the patient has undergone their cerebral angiogram.
You want to first check the insertion site for bleeding.
You want to advise the patient to keep their leg straight.
And then you want to check for blood flowdistal to that insertion site. So you're going to check for pulses, capillary refill, temperature, as well as color.
And then you want to encourage your patient to increase their fluid intake to help excrete that contrast dye.
Next up, we have an electroencephalogram, or EEG. This is a test that is used to identify seizures or sleep disorders. It can also be used on patients who have altered mental status, such as encephalopathy.
During the procedure, electrodes are placed on the patient's scalp, and the electrical activity of the brain is recorded.
In terms of nursing care, prior to the procedure, you want to have a patient wash their hair because those electrodes are not going to stick well to a greasy scalp.
You also want to advise your patient to arrive sleep deprived because sleep deprivation will make it easier and more accurate to diagnose epilepsy. You should also advise your patient to avoid stimulants or sedative medications prior to the procedure.
In addition, NPO is not required for an EEG. So it is required for a cerebral angiogram, which we just talked about, because that procedure uses anesthesia. Anesthesia is not used with an EEG, so NPO is not required.
During the procedure, hyperventilation or strobe lighting may be used to increase the likelihood of seizure activity. So you'll want to give your patient a heads-up about that possibility prior to the procedure.
Next, we have ICP monitoring, or intracranial pressure monitoring.
This is a very invasive procedure where a device is inserted into the patient's cranial cavity to measure their ICP. It is done in the OR, and it carries a huge risk of infection.
Indications for this procedure include the patient being in a coma, which means their Glasgow Coma Scale Score will be under eight.
So normal ICP is between 10 and 15mmHg.
Signs and symptoms that a patient has increased ICP can initially include symptoms such as restlessness, irritability, and a headache. But as that ICP increases, it can cause decreased level of consciousness, pupil abnormalities, abnormal breathing patterns such as Cheyne Stokes and BOS respiration patterns. It can also cause abnormal posturing, such as the cerebrate or decorticate posturing.
The next diagnostic test that I want to cover is a lumbar puncture.
During this procedure, a cerebral spinal fluid sample is obtained from the patient's spinal canal, and it's analyzed. So this may be done if we suspect the patient has meningitis, a subarachnoid hemorrhage, or other neurological disorder.
So pre-procedure, we want to have the patient empty their bladder, and then we should position the patient on their side in a fetal position, or alternatively, we can have them sit up and kind of lean over a table. So either way, we want the patient's back to be arched.
After the procedure, we should have the patient lay flat for several hours and increase their fluid intake.
We also need to monitor for signs of a CSF leak, which can include a severe headache.
So, if necessary, the patient can get what's called an epidural blood patch. So this is where a sample of the patient's blood is injected into that epidural space, where it clots and kind of seals off the area and prevents that leak.
The last diagnostic test I want to cover in this video is an MRI, or magnetic resonance imaging.
So this is an imaging procedure that uses strong magnetic fields and radio waves to make images of internal structures of the body. It provides better soft-tissue contrast than a CAT scan.
So prior to the procedure, you want to assess your patient for a history of claustrophobia, and if needed, you may need to give them an anti-anxiety medication.
You should have them remove all their jewelry and you should assess for contraindications, which include metal implants. So definitely check for things such as artificial joints or a pacemaker. And then, finally, you need to give them some earplugs. We don't need to, but you should, because MRIs are very loud.
All right. You guys ready for your quiz? I actually had a hard time picking only three questions because there's a lot of important information on these flashcards that I just reviewed. But here we go. Question number one. NPO is required prior to an EEG. True or false? The answer is false. NPO is not required. Question number two. How should a patient be positioned for a lumbar puncture? Answer. They should either be positioned on their side in a fetal position or stretched over a table such that their back is arched. Question number three. Irritability is an early sign of increased intracranial pressure. True or false? The answer is true.
Okay. I hope this video has been super helpful. If so, be sure to like it and leave me a comment. Take care and good luck with studying.
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