Vol.2-Ch.6 "PT Monitoring Tech" Flashcards
Describe the two main type of systems that operate the hear.
A mechanical system (valves, cardiac muscle, blood flow) and An electrical system (controls rhythm of contraction)
“It is a mechanical pump the runs on electricity”
The heart really has 2 pumps, a _____ and a _____ pump.
Right (A and V) and a left (A and V)
What is the hearts natural “pacemaker” and where is it located?
The Sinoatrial Node (SA Node) and it is located in the right atrium
How does the SA node create an electrical impulse?
Through depolarization; which occurs when the electrolytes Sodium and Potassium cross cell membranes and cause a shift in cell polarity
When a cardiac cell depolarizes is the inside of the cell more positive or negatively charged?
Positive
What is the bundle of His?
The atrioventricular (AV) fibers in the ventricles
What connects the SA Node to the AV Node?
Intraatrial pathways
What is the name of the system that spreads the electrical current in the heart from an inferior to superior direction across the myocardium?
The Purkinje system
What are the 3 types of ECG Leads?
- Bipolar
- Augmented
- Precordial
What is the name for the placement cites of the 3 pibolar leads (actually usually 4) and where does the name come from?
Einthoven’s Triangle, named after the creator of the ECG.
(There are usually 4 pads though, one placed on each limb, although the right leg is usually considered a ground or extra since the legs give virtually the same reading)
How fast does the ECG graph paper move?
25 mm/sec
What are the 4 ECG components and 2 time intervals?
- P Wave = Atrial Depolarization
- QRS complex = Ventricular Depolarization
- T Wave = Ventricular Repolarization
- U Wave = Occurs occasionally; they follow the T wave and usually indicate an abnormality
- PR interval = beginning of P to beginning of QRS
- ST segment = distance from S to T
What are the 3 bipolar lead placement sites?
Also, which is the most commonly used and why?
- Positive on left arm ; negative on right arm
- Positive on left leg ; negative on right arm
- positive on left leg ; negative on left arm
The second is the most common because it is usually sufficient at identifying life threatening arrhythmias.
If you suspect a mycardial infarction, is a single lead enough? If not what should be used?
No, a 12 lead is the best tool for identifying cardiac ischemia (not enough blood perfusion) or infarction.
What is an artifact?
Deflections on the ECG produced by other factors other than the heart’s electrical system such as: muscle tremors, shivering, pt moving, machine malfunction, or most likely and commonly loose leads.
What arteries deliver blood to the heart?
Right and Left Coronary Arteries (The left is bigger and has 2 parts)
What are the 3 zones of myocardial damage?
- Ischemia - Myocardium is oxygen deprived
- Injury - Myocardium is damaged from prolonged ischemia
- Infarction - Death of myocardial tissue
What is the main limitation of a 4 or 12 lead?
They do not give any info on the mechanical system of the heart (aka it doesn’t tell you if it is actually pumping or has anything to pump)
What do the 12 leads consist of?
3 bipolar leads 3 unipolar (augmented) leads 6 precordial (chest) leads
What are the 3 unipolar leads?
- aVR (pos on right arm ; neg on left arm and left leg)
- aVL (pos on left arm ; neg on right arm and left leg)
- aVF (pos on left foot ; neg on left and right arm)
What % of the oxygen usually binds to the hemoglobin molecule?
97%
Hemoglobin are made up of how many protein chains?
4, usually 2 alpha and 2 beta
Each protein chain in a hemoglobin contain what structure? What is significant about the structure? and what does it indicate about hemoglobin?
Each chain has a Heme which is where the O2 binds to the hemoglobin; therefore each molecule of hemoglobin can bind with 4 molecules of O2
What is the name of the molecule when O2 is attached to a hemoglobin? What about one that is not attached?
Oxyhemoglobin has O2 attached ; deoxyhemoglobin has no O2 present
What does Pulse Oximetry monitor?
The O2 saturation of the hemoglobin
What are 2 other locations other than the fingertip for a Pulse oximetry sensor to go?
Ear lobe or toe
How does a Pulse Oximetry reading know your SpO2 (aka oxygen saturation %)?
By shining a light and measuring the difference between the visible dark blood (deoxy blood) and bright blood (oxy blood) and measures the difference between the amounts of oxyhemoglobin and deoxyhemoblobin. The provided measurement is the % of hemoglobin bound with oxygen
What is an normal SpO2 range for a PT breathing room air?
95-100%
What is the main thing that will inhibit an accurate pulse oximetry reading?
Anything or any condition that inhibits perfusion to the spot you are taking a reading from
How much nitrogen and oxygen is in our air?
79% nitrogen and 21% oxygen
What is End Tidal CO2 (ETCO2) and what does it reflect about the cells?
It is the amount of CO2 exhaled and reflects cellular metabolism, circulation, and ventilation.
Is CO2 a base or an acid?
An acid that must be constantly eliminated from the body to maintain PH balance (b/w 7.35 and 7.45)
What does Capnometry measure?
Capnometry measures the amount of ETCO2 (end tidal CO2)
What are the 2 basic types of ETCO2 monitoring systems?
Qualitative Colorimetric devices or quantitative electronic devices (infrared)
What is a Colorimetric device? What does it measure? How does it measure it?
A colorimetric device is basically a disposable plastic chamber with a piece of litmus paper enclosed in it; it measures the pH of the gas that is exhaled and can change from breath to breath from purple to yellow (originally used to verify an ET tube placement)
How do electronic ETCO2 devices detect CO2 in the exhaled breath?
By infrared tech
How many phases are there per cycle given on an electronic ETCO2 readout? and which phase has the actual ETCO2?
There are 4 phases; phase 3 records the highest level of of ETCO2
What is the difference between capnography and capnometry?
Capnometry = a number capnography = a waveform
What are the three basic applications for ETCO2 monitoring?
- Qualitative Colorimetric ETCO2
- Continuous Waveform Monitoring (w/ ETT)
- Continuous Waveform Monitoring (w/out ETT)
What is the number 1 cause of poisoning and how is the poison created?
Carbon Monoxide ; a byproduct of incomplete combustion of carbon containing compounds such as wood or petroleum products.
How much more likely is carbon monoxide to take a place on a hemoglobin chain than oxygen?
200 times
How long does a cell with carbon monoxide attached (carboxyhemoglobin) last in the body? How much shorter is it’s half life when PT is given 100% O2 therapy?
They typically last 4-6 hours before expelled but with O2 therapy it can be decreased to 80 minutes
What and how does pulse CO-Oximetry measure?
I measures the amount of carboxyhemoglobin using 8 different wavelengths of light shined into the nail bed
What state is the Heme (iron containing protein in a hemoglobin chain) when there is no O2 attached? What is it when it is attached? What are the names for the two charged states of the iron?
A heme w/ O2 is in a Ferrous (Fe2+) charged state
A heme w/out O2 is in a Ferric (Fe3+) charged state
What does the process called oxidation change in a hemoglobin? What is a hemoglobin cell that is oxidized called?
When oxygen binds to the iron in a Heme the charges changed from Fe2+ to Fe3+ through a process called oxidation ; a hemoglobin that has been oxidized is called a Methemoglobin
Can oxygen bind to a a Heme when the iron in it is at a Fe3+ charge? (post oxidation)
No
How do Ferric Heme groups (Fe3+) change back to Ferrous Heme groups (Fe2+)?
Through an enzyme called NADH-Dependant methemoglobin reductase (90-95% with this; 5-10% with a very similar enzyme)
What is methemoglobinemia? What are the 2 major causes?
Hypoxia caused by raised levels of methemoglobin ; usually caused by raised production of methemoglobin (usually via drugs) or by a lack of production of Enzymes to help revert the charge of hemoglobin
What can you measure with a multi-wavelength pulse CO-Oximetry device?
oxyhemoglobin (SpO2), carboxyhemoglobin (SpCO), and methemoglobin (SpMet)
What are the 3 types of endocrine cells in the islets of Langerhans and what hormone does each one secrete?
- Alpha cells (25% of the tissue) secrete glucagon
- Beta cells (60% of the tissue) secrete insulin
- Delta Cells (10% of the tissue) secrete somatostatin
Glucagon breaks down glycogen which is the stored form of glucose in the liver (helps raise blood sugar when low)
Somatostatin regulates/inhibits the secretion of glucagon and insulin
What is the normal blood glucose range?
80-140 mg/dL
over is hyperglycemic
under is hypoglycemic
What are the 4 most commonly tested electrolytes?
Sodium, Potassium, chloride, and bicarbonite
less tested are calcium, magnesium, and phosphate
Electrolytes with a positive charge are ____ and with a negative charge are _____.
Positive = cations (sodium, potassium, magnesium, phosphate)
Negative = anions (chloride, bicarbonate, phosphate)
How do you calculate the anion gap? What is it normally at?
Add the measured cations (pos) and subtract the measured anions (neg). It is normally at 12 to 14 mEq
What 2 devices off comprehensive blood analysis? (Point of care testing)
the i-STAT or the epoc Blood Analysis System
What does arterial blood gas (ABG) testing show?
Info on PT ventilation and perfusion status as well as over all acid-base balance status
(not usually pre-hospital care)
What is a normal ETCO2 reading?
35-45 mmHg
