Week 1 - Basic Clinical Monitoring (Cardiovascular) Flashcards
Systematic approach of anesthesia consists of (Sweeping)
Inspection, auscultation, and palpitation
* I Ate Pizza
Most common required diagnostic tool for monitoring the heart
ECG/EKG
Which leads are best for watching for ST changes
V2 and V3
How do you determine ST elevation or depression?
If the ST segment is above or below isoelectric line (PR segment)
How many ECG leads should ideally be monitored during operations?
Generally 3 (or more)
Viewing two or less can result in myocardial ischemia
How many cm must a PAC travel to reach the RA via the Right IJ vein
15-25 cm
From here each additional 10 cm should bring you to the next structure. 15 Junction of SVC/RA, 15-25 RA, 25-35 RV, 35-45 PA, and 40-50 for PA wedge pressure.
What might cause resistance during PAC removal?
- Chordae tendineae entanglement needs CXR to rule this out.
A 12 lead ECG should be done for which patients?
those at risk for ischemic events
Which leads should be monitored for ST changes when a preoperative ECG was preformed?
Whichever leads showed ST changes
Which leads are ideal to observe during a case in which a patient has an unremarkable ECG reading?
V3, V4, V5, III, and aVF
Which lead should be monitored to observe narrow QRS readings
II
V3 lead detects _________ the earliest and most frequently
Ischemia
You advance a PAC 10 cm but don’t see a change in waveform, what could this mean?
Line coiling
Before withdrawing a PAC, what must you do?
Check balloon is fully deflated
What is a textbook PA pressure
25/10 (quarter over dime)
What do a, c, and v waves signify when a PAC is in the RA
a = RA contraction
c = Tricuspid valve closure
v = RA filling
Normal pressure waveform readings in the heart
What does the dicrotic notch represent in a PA pressure waveform?
Closure of the pulmonic valve.
Upstroke = Systole (RV ejection)
Downstroke = Diastole (RV filling), contains dicrotic notch.
How would you interpret a low RA and PA pressure?
Hypovolemia, transducer too high
What could be an explaination for a loss of “a” waves in a RA waveform tracing?
A-Fib or V pacing
When is the best time to determine the PA/PAOP pressures within a patient?
At end of expiration. Pleural pressure should = atmospheric pressure
What could be the causes of an elevated PA pressure?
Catheter whip, catheter coiling, dilated pulmonary artery, pulmonary HTN
What is a normal SVRI value
1760 - 2600 dynes/sec
represents LV after load, <1760 indicates dilation, >2600 indicates constriction
What does cardiac index represent?
Cardiac output taking into account the patients height and weight. Normal 2.8-3.6 L/per min
Adequacy of tissue perfusion, BP, oxygen deliver, and waste removal.
Which direction would you expect a lactate level to trend with a lowering cardiac index?
Elevating, above 2
By which method is a cardiac index most frequently attained?
Thermodilution –> Injectate is usually D5W or .9NS (similar densities) and should be room temp.
Increased CI value = low injectate volume or is too warm, thrombus on PAC, partially wedged PAC
Decreased CI value = too much injectate or is too cold
What is the goal of placement for a PAC?
West zone III of the lung
What is Wests zone III of the lung?
Where Pa > Pv > PA
Pa = arterial pressure
Pv = venous pressure
PA = alveolar pressure
What is SvO2
Mixed venous oxygen saturation
* Indirectly monitors O2 delivery. Normal values of 55-75%. Dependent on CO. Decreased values with decreased cardiac output besides sepsis and cyanide toxicity.
What is ScvO2
Central Venous Oxygen Saturation
* Regional indicator of O2 delivery in the head and upper body. Usually 2-3% lower than SvO2.
If lactate is greater than 2, how often should you draw levels
Q 2 hours
What would you suspect with high RA, PA, and PAOP pressures?
Cardiac tamponade, ventricular interdependence, transducer is too low.
or left heart failure (although RA/ CVP could be normal-high)
Why might you be seeing a overshooting arterial blood pressure waveform?
Too small of a catheter (Normal is 20 gauge), decreased arterial compliance, and pre-existing vascular disease
What is considered the gold standard of blood pressure monitoring?
Arterial blood pressure, most common artery used is the radial artery
Cons of an arterial BP catheter
More invasive than NIBP, infection, injury to nerves or veins around catheter, loss of limb due to poor collateral circulation
How often should blood pressure be recorded during an operation?
Q5 mins during maintenance, Q1 min during induction
Properly fitting BP cuffs should have bladder dimensions _________ of patients circumference of extremity
40%
Loose BP cuff below the heart/too small of a cuff would have a ______ reading
falsely elevated
What is a Transesophegeal Echo? (TEE)
Use of sound waves to define anatomic structures of the heart via probe placed in esophagus
Abnormal wall motion of the heart can be described as what three terms?
Hypokinesia = Contraction less vigorous than normal, wall thickening decreased
Akinesia = Absence of wall motion, indicative of MI
Dyskinesia = Paradoxical movements, hallmark sign of MI or ventricular aneurysm.
Causes of a dampened arterial pressure?
Flexed wrist, air bubbles in tubing, thrombus, catheter kinking.
Loss of the dicrotic notch with an underestimated BP
How do you calculate MAP?
SBP +(DBP x 2)/ 3
Diastolic phase is 2x as long as systolic
Sepsis, Cyanide toxicity, and hypothermia cause a ________ SvO2 reading
Elevated
SvO2 is dependent on _________
Cardiac output
What patient manifestations would cause a decreased Sv02?
Hyperthermia, shivering, seizures, and hemorrhage.
These things cause increased O2 demands, thus decreasing SvO2
What could be the cause of an unpredictable CO value via thermodilution?
R –> L or L –> R ventricular septal defect, tricuspid regurgitation
What are the disadvantages to CCO monitoring? (continuous cardiac output)
Can’t determine rapid changes. 3-6 minutes behind current CO. Also not accurate if CO is less than 2
What does PVRI represent and what are the normal values?
RV after load, 40-225
Difference of pressure across the pulmonary circuit
Pulmonary artery pressure minus PAOP/CI X 80
Precordial leads should be placed by __________ of the costae, not by gross visual examination
palpitation
Why should the PAC with an inflated ballon only remain in the RV for as little amount of time as possible?
To reduce the incidence of ventricular ectopy
What is RVEDP used for?
To estimate RVEDV, which is used to estimate RV preload, and less accurately LV preload
On a CVP pressure, the A wave follows after _________ depolarization, and the C and V waves follow after ___________ depolarization
atrial, ventricular (C wave starts at the QRS, whereas V starts at the beginning of the ST segment)
How can risks associated with placing a radial arterial line be minimized?
- Position the hand and wrist on an arm board
- Place a roll beneath the wrist
- Fingers and the thumb should be taped securely across the board
What needle gauge is used for an arterial line?
20 gauge (22 gauge is optional)
What is the technique to placing an arterial line?
Bevel up, at a 45 degree angle insert toward the palpable pulse (if a bone is encountered, withdraw slightly and move laterally and re advance). Once blood is seen, reduce the angle of the needle to 30 degrees, and advance slightly.
In regard to a TEE, what is the best angle to view SWMA (segmental wall motion abnormality) for myocardial ischemia?
Short axis at the mid papillary muscle level
