Patient Care Flashcards
CT examinations of trunk order of oral contrast
Should be ordered before barium contrast studies or after sufficient time to allow for bowel clearance
Patient instructions prior to examination
Particularly during contrast studies, pt should be instructed to empty bladder to reduce possibility of discomfort
Informed Consent
- “Informed” is when procedure, risks, benefits, and alternatives are clearly explained in language pt fully comprehends
- Any questions must be adequately answered by qualified personnel
- Pt or legal representative must sign consent form (parent or legal guardian signs for minor)
Implied consent
When a patient is in need of immediate medical services but is unconscious or is physically unable to consent to treatment, services are rendered with the assumption the pt would consent if able
Immobilization
- Cushions, straps, and other safety devices that may be carefully used to help the patient hold still during data acquisition
- Breath-hold, which is particularly useful during chest and abdomen imaging
Levels of patient consciousness
- ALERT: have the ability to fully respond to all stimuli, including answering questions
- LETHARGIC: appears drowsy but can be aroused
- OBTUNDED: in a more depressed level of consciousness and may not easily be aroused from a state of confusion
- STUPOR: a state of near unresponsiveness (semicomatose)
- COMA: pt is completely unresponsive to stimuli
Vital signs
Temperature, pulse, blood pressure, and respirations
Normal body temperature
97.7 to 99.5 F (36.5 to 37.5 C)
Normal pulse rate
ADULTS 60-100 bpm
CHILDREN 70-120 bpm
Normal blood pressure
120/80 mm Hg (systolic/diastolic)
Systolic blood pressure
Indicates the pressure within arteries during cardiac contraction
Diastolic blood pressure
Is measured during the relaxation of the heart
Normal respiration rate
ADULTS 12-20 breaths per min
CHILDREN 20-30 breaths per min
Blood oxygen levels
95-100%, measured by pulse oximeter
Cardiac cycle
Series of blood flow-related events that occur from the beginning of one heartbeat to that of the next. Divided into three stages:
1. Atrial systole
2. Ventricular systole
3. Complete cardiac diastole
Heart rate
Frequency of cardiac cycle
Diastole
In relation to cardiac cycle, refers to relaxation of heart muscle
Systole
In relation to cardiac cycle, refers to contraction of heart muscle
Atrial systole
- Contraction of the left and right atria
- Corresponds to the onset of the P wave
Ventricular systole
- Contraction of the left and right ventricles
- Beginning of the QRS complex
Complete cardiac diastole
- Period of relaxation after heart contraction
- Consists of ventricular diastole and atrial diastole
- Corresponds to the T wave
Cardiac CT
-Typically acquired during diastolic phase
-pts with slower heart rates have longer diastolic phases and therefore produce better cardiac exams (65 bpm is optimal)
Beta-adrenergic (beta-blockers)
May be used to reduce pt heart rate
Sublingual nitroglycerin
May be administered before MSCT study to cause dilation of coronary vessels
Hypoxemia
Condition whereby the pt suffers from low concentration of oxygen in the blood
Hypoxia
-Insufficient oxygenation of tissue at the cellular level
-can lead to general physiologic concerns, including headache, dizziness, and nausea
-can lead to more serious complications, such as ataxia, tachycardia, and pulmonary hypertension
-left untreated, can result in cyanosis, low blood pressure, and death
Ataxia
Loss of muscular coordination
Pulmonary hypertension
Increased blood pressure in pulmonary vasculature
Options for oxygen delivery
- Nasal cannula: 1-5 LPM (liters per min)
- Oxygen mask: >6 LPM
Nonrebreathing mask
Includes an attached reservoir that fills with oxygen and provides higher percentage of delivery. Includes a one-way valve that prevents pt exhaling into reservoir
Blood urea nitrogen (BUN)
indicate renal function
7 to 25 mg/dL
Creatinine
0.5 to 1.5 mg/dL
BUN/creatinine ratio
6:1 to 22:1
Glomerular filtration rate (GFR)
Approximation of creatinine clearance or the rate by which creatinine is filtered from the blood stream
> 90 to 120 mL/min
Prothrombin time (PT)
Measure of blood coagulation
approx. 12 to 15 sec
international normalized ratio (INR)
- calculated to standardize PT results due to the inherent differences in tissue factor used to measure PT
-INR compares patient’s PT with a control sample for a more accurate result
0.8 to 1.2
Partial thromboplastin time (PTT)
used to detect abnormalities in blood clotting
platelet count of 140,000 to 440,000 per mm^3 of blood
d-dimer
measures the presence of elevated amounts of d-dimer in the bloodstream, which may indicate recently degraded blood clots
liver function test (LFT)
measures the levels of various enzymes and proteins in circulating blood, to screen for liver damage
anxiolytic medications
medications prescribed to reduce anxiety. Include benzodiazepines and selective serotonin reuptake inhibitors
benzodiazepines
diazepam (Valium)
alprazolam (Xanax)
clonazepam (Klonopin)
lorazepam (Ativan)
selective serotonin reuptake inhibitors (SSRIs)
paroxetine (Paxil)
sertraline (Zoloft)
fluoxetine (Prozac)
escitalopram (Lexapro)
iodinated contrast administration routes
- into bloodstream via IV
- directly into targeted vein or artery
- directly into intrathecal space (myelography)
- directly into joint space (arthrography)
- orally to visualize GI tract
Osmolality
-the agent’s propensity to cause fluid from outside the blood vessel to move into the bloodstream
-greatly affects contrast media’s potential for adverse effects in pt (nonionic, low-osmolar are less likely)
ionic contrast media
salts consisting of sodium and/or meglumine; when injected into bloodstream, each molecule (consisting of three iodine atoms) dissociates into two charged particles (ions)
nonionic contrast media
non-salt chemical compounds (consisting of three iodine atoms) that do not dissociate in solution
osmolality of contrast media
HIGH-OSMOLAR CONTRAST MEDIA (HOCM): ionic contrast media, e.g. ilthalamate meglumine (Conray) & diatrizoate sodium (Hypaque)
LOW-OSMOLAR CONTRAST MEDIA (LOCM): nonionic contrast media, e.g. iohexol (Omnipaque), iopamidol (Isovue), & ioversol (Optiray)
ISO-OSMOLAR CONTRAST MEDIA (IOCM): has same osmolality of blood, e.g. Iodixanol (Visipaque)
enteral contrast media
-administered orally and/or rectally to opacify GI tract
-routine transit time through GI tract is between 30 and 90 min
considerations for enteral contrast
-BARIUM SULFATE may not be used in suspected perforations
-BARIUM SULFATE contraindicated in pre-surgical pts (or other invasive procedures of abd/pel)
-BARIUM SULFATE can be harmful if aspirated
-WATER-SOLUBLE are usually more palatable and result in less GI distress
-WATER-SOLUBLE may be contraindicated in pts with iodine allergy
Typical contrast allergy premed regimen
combination of antihistamine like diphenhydramine HCl (Benadryl) and corticosteroid (prednisone or methylprednisone) taken at timed intervals as early as 12 to 24 hours before injection
breakthrough reaction to contrast
-repeat reaction in pt who has undergone pretreatment.
-pts are at greater risk of moderate or severe allergic reactions in subsequent contrast administration
contrast to pregnant and nursing mothers
-ok to inject pregnant pt, but care must be taken because risk of reaction in fetus is unknown
-ok to inject nursing mother, but pt is advised to pump and dump for 24 hours after injection
serum iodine concentration
-measure of the amount of iodine within the bloodstream
-adequate opacification for CT exams is 2 to 8 mg/mL
distal large bowel (including sigmoid colon and rectum) studies
administer contrast 4 to 6 hours before scan time or may be administered rectally
intrathecal
injection directly into the space surrounding spinal cord (e.g. myelogram)
intraarticular
injection directly into a joint space (e.g. arthrography)
advantages of power injection over hand injection
- consistent, reproducible flow rates
- precise volume/dosage control
- higher injection rates for optimal contrast enhancement
- automatic delays for proper enhancement patterns and multiphase imaging
reaction to contrast media
a severe, life-threatening reaction is most likely to occur within the first 20 min after administration
adverse recations
ALLERGIC-LIKE: similar to other allergic reactions to foods or medicines
PHYSIOLOGIC: cardiac arrhythmia, seizure, and pulmonary edema
mild reactions to contrast
ALLERGIC-LIKE: hives (urticaria), swelling (edema), nasal stuffiness/sneezing, itchy throat
PHYSIOLOGIC: nausea/vomiting, sensation of warmth/flushing, sweats/chills, anxiety, altered taste, mild hypertension, transient vasovagal reaction
Are non-life-threatening and typically require no treatment.
moderate reactions to contrast
ALLERGIC-LIKE: moderate-to-severe urticaria (hives), diffuse erythema, facial edema, tightening throat, wheezing
PHYSIOLOGIC: moderate-to-severe nausea/vomiting, vasovagal response requiring treatment, tachycardia from hypotension, chest pain
Treatment can include bronchodilator inhaler and/or oxygen (wheezing), Benadryl (hives), elevation of legs and IV fluids (hypotension)
severe reaction to contrast
ALLERGIC-LIKE: facial, laryngeal, and/or pulmonary edema; anaphylactic shock; severe erythema; profound hypotension; severe wheezing/bronchospasm
PHYSIOLOGIC: cardiac arrhythmia, seizure, severe hypertension, cardiopulmonary arrest, death
Potentially life-threatening and require immediate treatment.
