Tuesday, March 18, 2008

Diagnostic Tests made EZ

I remember trying to answer questions about the care of patients before, during and after certain diagnositic tests, and having no clue, mainly because I didn't really know what the test really was. So I am posting some pictures with a common point or two related to that test, that the NCLEX and the USMLE frequently asks. Hope you find this makes it a bit EZer to grasp.

Bronchoscopy (BAL)

  • Definitive diagnosis of TB

  • Lidocaine used intraoperatively to numb gag and cough receptors so assure patient has gag reflex back before feeding or giving fluids

Chest Xray

  • Xray can be used for multiple diseases, and can be focused on chest, abdomen, cervical spine, extremeties, etc

  • Portable xrays are frequently used for many respiratory complaints so prepare to see this ordered when you pass the boards and become an RN

  • In any female inquire if there is any possibility they are pregnant, as xray is contraindicated if so

  • Remove jewelry as will show up on xray and cover possible results


  • In this procedure, a needle is inserted into the pleural space (membrane surrounding lungs) to draw out fluid

  • May be a one time withdrawal, or may leave a drain in place

  • Used for Pleural Effusions, Empyema, etc.

  • Patient often placed on affected side, to allow good lung freedom to breathe

  • Cardiocentesis, is similar procedure used for fluid around heart (Tamponade)

Pulmonary Angiography

  • Definitive test used as gold standard diagnosis of Pulmonary Embolism

  • Contrast material is inserted via a catheter, directly into lung vasculature (often entered through Femoral vein) and the flow of contrast is seen under fluoroscopy

  • Expensive and time to test is often greater than desired, so CT or VQ scan often replace for PE

  • Contrast material is used, so caution for allergies or kidney failure. As a general rule patients should receive more than normal fluids for 24 hours after contrast to help flush it ouf of system.

Arterial Blood Gas

  • ABGs are often requested when acute respiratory or metabolic issues are occuring

  • You may be on a unit very soon that will require you to perform this task

  • Remember to do an Allen Test first (occlude radial/ulnar arteries, and release one then the other observing return of blood flow to hand in between)

  • Do not suggest if your plan of care would not change with result possibilities

  • When analyzing ABGs, look at pH first! High is alkalosis, low is acidosis. Then simply see if bicarb or CO2 has changed to determine what type is present (bicarb is metabolic, CO2 is respiratory)

Circular CT

  • The most common type of test used for diagnosing Pulmonary Embolism, as well as a host of other diseases. This test produces picture slices through the body, like you were sliced in half.

  • Contrast is usually used for circular CT, and can be seen in picture above as white material. Large circle on bottom of picture is the Aorta, and the smaller circles to the right are pulmonary arteries. Notice the dark circle in middle that resembles a donut? That is an embolus in the lung (PE)

  • Remember all issues with contrast (allergies, kidney failure, patient on Metformin?)

  • See pic below for what a circular CT looks like

MRI (magnetic resonance imaging)

  • Similar results to a CT, but much prettier pictures. Due to the improved clarity are becoming gold standard for many diseases

  • But test can take hours to perform, so not the best choice for rapidly deteriorating conditions.

  • Since the test uses magnets, the patient can not have metallic heart valves or cochlear implants

  • Contrast may also be used

  • See below for image obtained by MRI, noticing the various slices we are able to obtain and use

CT (computerized tomagraphy)

  • While the picture may not be as clear as an MRI, these images are actually better at seeing fluids, such as blood, and thus are usually first line for possible hemorrhagic strokes and other diseases

  • Notice in picture above, to the right, contrast has been used which allows certain areas to become much brighter. In these pictures, the large tumor on the right is enhanced by contrast.

  • All of the issues of contrast must be considered however

  • See below for pic of CT,,,again

Lumbar Puncture

LP Indications
• Diagnosis of Meningitis
• Diagnosis of Subarachnoid bleed
• Diagnosis of Multiple Sclerosis
• Diagnosis of Malignancy
• Introduction of contrast or anesthetics

  • LPs are taken with patient in fetal position (on side, legs drawn up, head on chest)
  • Be on the alert for severe headache post procedure from drawing too much CSF out

  • In this procedure, an LP is performed, and dye is injected under fluoroscopy.
  • Xrays are then taken to measure flow of CSF and look for constrictions
  • Dye may be oil or water based
  • If an oil-based dye was used, the patient is kept flat in bed for approximately 8 hours
  • If a water-soluble dye was used, bed rest is maintained, with the head of the bed elevated 30 degrees for 6 to 8 hours
OK...hope that helped a bit with getting a picture of certain diagnostics you will run across commonly in the hospital or on the NCLEX. Good luck!


Imaginethat savingtheworld said...

Thank you

a.lieu said...

Thank you!!

Anonymous said...

This was a great help. Thanks for taking the time out to make this!!