Week 2 Hemodynamic Monitoring Flashcards
(167 cards)
1
Q
T of F: The distribution of ST depression type ischemia correlates exactly with the specific location of CAD.
A
False;
ST segment depression correlates poorly with location of demand.
2
Q
How does mechanical ventilation affect CVP?
A
Increases CVP about 3-5 mmHg
(Think of positive pressure and increased thoracic pressure)
3
Q
Describe the “a” wave of the CVP waveform.
A
- caused by atrial contraction
- (follows the P-wave on ECG)
- represents end diastole
- corresponds with “atrial kick” which causes filling of the right ventricle
4
Q
For the 5-lead ECG system, which lead is the preferred lead for special arrhythmia monitoring?
A
V1
5
Q
Normal cardiac output and stroke volume.
A
CO: 4.0-6.5 L/min (average: 5 L/min)
SV: 60 - 90 mL (average: 75 mL)
6
Q
The increase in left ventricular preload and decrease in left ventricular afterload (from positive pressure ventilation) produce what hemodynamic effects?
A
- increase in left ventricular stroke volume
- increase in cardiac output
- increase in systemic arterial pressure (in the absense of changes in peripheral resistance)
7
Q
What is CVP monitoring and what are normal values?
A
Central Venous Pressure
Gives estimation of right atrial pressure and RV preload
Normal: ~2-7 mmHg in a spontaneous breathing patient
8
Q
Describe ST segment depression and when are we likely to see it?
A
ST segment: flat or downslope of > or = to 1 mm
***This is a demand issue***
Demands of the patient are exceeding the cardiac output.
9
Q
Name a few other causes of ST depression besides myocardial ischemia.
A
- drugs (most notably digitalis)
- temperature changes
- hyperventilation
- position changes
10
Q
According to the AANA Standard 9: Monitoring and Alarms, when a physiological monitoring device is used…..
A
pitch and threshold alarms are turned on and audible.
11
Q
Name 4 major sources of artifact for pulse oximetry reading and describe how we can remedy them?
A
-
Ambient light (remedy by covering pulse ox)
- Cover the the sensor with an opaque shield
-
low perfusion (weak pulse, low AC to DC signal ratio)
- **Significantly erroneous reductions in SpO2 readings may be observed for systolic blood pressures lower than 80 mmHg**
- Whenever you have a lot of noise from low perfusion, it’s usually equal in the red and the infared signals and the ratio of the two is usually at a 1:1 ratio with that, you might see an SpO2 that reads 85% which is inaccurate obviously
-
venous blood pulsation (caused by patient motion, among other things)
- The pulse oximeter makes the assumption that whatever is pulsing must be arterial blood. In most cases, this is true, but in some situations (patient motion) there can be large venous pulsations that can produce erroneously low saturation values
- If the device averages its measurements over a longer period of time, then the effect of an intermittent artifact is usually less. HOWEVER, this longer averaging period also slows the response time to an acute change in SaO2, and it may result in “frozen” SpO2 values being displayed when the true saturation is changing
- The purpose of the delay is using the averaging time to compensate for the motion artifact, but what it means is you’ll see a decline in the patient before you see a drop in your SpO2 or an improvement in your patient before you see an increase in SpO2 back to normal
- additional light absorbers in the blood (IV dyes, dyshemoglobins)
**All these sources of artificats produce a low signal-to-noise ratio, resulting in either erroneous SpO2 values or no value at all**
12
Q
Describe ST segment elevation.
A
ST segment: elevation > or = 1 mm
***This is a supply issue***
Think endothelial plaque rupture and complete occlusion of a coronary artery
13
Q
For NIBP cuffs, bladder width should be approximately ___% of the circumference of the extremity. Bladder length should be sufficient to encircle at least ___% of the extremity. What else do we need to do to ensure proper fitting of NIBP cuff?
A
40; 80
Apply snuggly with bladder centered over the arter_y* and *_residual air removed
14
Q
Describe the “x” descent of the CVP waveform.
A
- systolic decrease in atrial pressure due to atrial relaxation
- atria are in diasole, tricuspid valve remains closed
- mid-systolic event
15
Q
Define overdamped waveform and list potential causes of an overdamped waveform.
A
Waveform shows diminished pulse pressure, flattened, low amplitude
Potential causes:
- loose connections
- air bubbles
- kinks
- blood clots
- arterial spasm
- narrow tubing
16
Q
Septal Ischemia: Which leads will show ST elevation and which coronary artery is likely affected?
A
Left descending coronary artery (per slide)
Left anterior descending (LAD)
Leads: V1, V2
17
Q
Describe oscillometry as a measurement of NIBP.
A
**Typically what is used in the OR**
Automated cuff - measure changes in oscillatory amplitude electronically, derives MAP, SBP, DBP by using algorithms.
- 1st oscillation correlates with SBP
- MAP = maximal degree of detectable pulsation
- Oscillations cease at DBP
- DBP most unreliable oscillometric measurement
- DBP is mathematically inferred from the SBP & MAP
- when BP is low, DBP becomes more unreliable
***In general, oscillometric pressures underestimate SBP and overestimate DBP → significantly underestimate pulse pressure calculation***
***During periods of hypertension, tend to underestimate***
***During periods of hypotension, tend to overestimate***
Errors in cuff measurement:
- too small/too large cuff
- stiff atherosclerotic arteries are restant to compression
- external compression by patient motion
- surgeon leaning on BP cuff
18
Q
Aortic regurgitation can show which types arterial waveform abnormalities?
A
Bisferians pulse (double peak)
wide pulse pressue
19
Q
List uses of TEE in the OR.
A
- unusual causes of acute hypotension
- pericardial tamponade
- pulmonary embolism
- aortic dissection
- myocardial ischemia
- valvular dysfunction
- valvular function
- wall motion abnormalities
20
Q
Name 3 methods of verification for intubation of the trachea or placement of other artificial airway device.
A
- auscultation
- chest rise/chest excursion
- confirmation of expired carbon dioxide/end tidal CO2
21
Q
Describe the components of an arterial pressure waveform.
A
Peak: ejection of blood from the left ventricle into the aorta during systole
Dicrotic notch: closure of the aortic valve
Followed by peripheral runoff during diastole
22
Q
What is pulse oximetry?
A
- Method of measuring hemoglobin oxygen saturation (SpO2)
23
Q
Why is there a delay of 120 - 180 milliseconds between the R wave (on EKG) and the upstroke of systole (on arterial waveform)?
A
Represents the delay between actual ventricular depolarization and the arrival of the signal to the pressure transducer.
OR (from slide, way more detailed)
Interval reflects totaly time required for depolarization of the ventricular myocardium, isovolumetric left ventricular contraction, opening of the aortic valve, left ventricular ejection, propagation of the aortic pressure wave, and finally, transmission of the singal to the pressure transducer.
24
Q
Describe a PA catheter, including french size, length, and lumens.
A
- 7 french (introducer is 8.5 french)
- 110 cm length marked at 10 cm intervals
- 4 lumens
- distal port - PAP
- second port - 30 cm more proximal - CVP
- third lumen - balloon
- fouth wire for temp thermistor
25
**Cardiac Tamponade** - CVP waveform
Dominant **x descent**
attenuated **y descent**
26
Describe proper placement of the tip of the CVC.
* tip within the SVC, just above the junction of the vena cava and the RA
* parallel to the vessel walls
* positioned below the inferior border of the clavicle
* above the level of 3rd rib at T4/T5 interspace, the carina, or takeoff of the right main bronchus
27
What is diastolic blood pressure?
trough pressure during diastolic ventricular relaxation
\*\*\*changes in _DBP_ reflect _coronary perfusion pressure_\*\*\*
28
Indications for central venous cannulation
* CVP monitoring
* PA catheterization and monitoring
* transvenous cardiac pacing
* temporary HD
* Drug administration
* concentrated vasoactive drugs
* hyperalimentation (i.e. TPN)
* chemotherapy
* prolonged antibiotic therapy (i.e. endocarditis)
* Rapid infusion of fluids (via large cannulas)
* trauma
* major surgery
* aspiration of air emboli
* inadequate peripheral IV access
* sampling site for repeated blood testing
29
List the 4 types of hemoglobin in adult blood.
* oxygenated hemoglobin
* deoxygenated hemoglobin
* carboxyhemoglobin (concentrations 1%-3%)
* methemoglobin (\<1%)
30
How do we meausure perfusion pressure (pressure difference) for the systemic circulation? Pulmonary circulation?
*_Systemic circulation_*: **MAP - CVP**
*_Pulmonary circulation_*: Mean pulmonary artery pressure (MPAP) minus the left atrial pressure (usually estimated by a pulmonary artery wedge pressure) (PAWP)
**MPAP - PAWP**
31
**Insertion of a PA Catheter**: distances from the R IJ to distal structures.
**_Structure_ _Distance inserted from skin (cm)_**
## Footnote
Vena cave and RA junction 15
Right atrium 15-25
Right ventricle 25-35
Pulmonary artery 35-45
Wedged in pulmonary capillary. 40-50
32
What is subendocardial ischemia and how does it present on ECG?
Ischemia confined to subendocardial area
Presents at **ST segment depression**
\*\*\*typically occurs during episodes of symptomati or asymptomatic (silent) stable angina pectoris\*\*\*
33
**Inferior wall ischemia**: Which leads will show ST elevation and which coronary artery is likely affected?
**RCA** - right coronary artery
**Leads**: II, III, aVF
34
Pulse Pressure
SBP - DBP
35
**Right ventricular ischemia** - CVP waveform
Tall **a and v waves**
steep **x and y descents**
M or W configuration
36
What is systolic blood pressure?
peak pressure generated during systolic ventricular contraction
\*\*changes in _SBP_ correlate with changes in _myocardial O2 requirements_\*\*
37
**Pulsus paradoxus** (exaggerated decrease in systolic blood pressure during spontaneous inspiration) may be indicative of?
cardiac tamponade
38
What is the normal electrical axis of the heart?
"The main vector of the QRS complex in the front plane serves to calculate the electrical axis of the heart."
**Normal**: between -30 and +90 degrees
39
**True of False**: The Allen Test has a poor predictive value of ischemic injuries following a line insertion.
**True;**
Ischemic injuries seen even in patients with normal Allen test
40
**True of False**: The continuous flush device of a transducer system provides a continuous, slow infusion of saline at about 1-3 ml/hr.
**True;**
The continuous, slow flush of 1-3 ml/hr prevents thrombus formation within the arterial catheter.
41
Describe doppler as a measurement of NIBP.
* based on shift in frequency of sound waves that is reflected by RBCs moving through an artery
* \*\*measures only SBP reliably\*\*
42
As the pressure wave travels from the central aorta to the periphery, how does the morphology of the arterial waveform change?
* arterial upstroke becomes steeper
* systolic peak increases
* dicrotic notch appears later
* diastolic wave becomes more prominent
* end-diastolic pressure decreases
43
What is the most common complication of placing a subclavian line?
Pneumothorax
## Footnote
(although, unintended arterial puncture may actually be more frequent)
44
Filtering capacity should be set to _________ mode.
diagnostic
45
Describe finger readings as a measurement of NIBP.
* \*\*subject to significant limitations\*\*
* **disadvantages**: finger arteries are prone to spasm with the potential for distal ischemia, hand position will influence pressure values
46
Extreme wrist dorsiflexion following establishment of an A line should be avoided to prevent injury to the _______ nerve.
median
47
Name scenarios you may obtain a falsely **high** BP.
* cuff to small
* cuff too loose
* extremity below level of heart
* arterial stiffness (atherosclerotic change) - HTN, PVD
48
List complications of transesophageal echocardiography.
* esophageal trauma
* dysrhythmias
* hoarseness
* dysphagia
49
How will the SpO2 read when you have a methemoglobinemia? Why?
SpO2 will approach and remain at ~85%
* MetHb absorbs a significant amount of light at **both** 660 and 940 nm.
* As a result, in its presence, the ratio of light absorption approaches unity. An R value of 1 represents the presence of *_equal concentrations of O2Hb and deO2Hb_* and corresponds to an **SpO2 of 85%.**
* In a patient with methemoglobinemia, the SpO2 is 80% to 85% irrespective of the SaO2.
50
Which precordial leads are the preferred leads for **ischemia monitoring**?
V3-V5
51
What is the preferred site for CVC insertion? Why?
Right Internal Jugular Vein (R IJ)
* predictable anatomical location
* palpable surface landmarks
* straight course to the SVC
* really accessible
* high success rate of placement, \>90%
52
Contraindications for placement of CVC.
* R atrial tumor
* contralateral pneumothorax
* infection at site
53
INFO CARD
Proper ECG Placement: 3 leads
54
If you plan to insert an a line, and you're concerned about your patient's stability during induction, when should you insert the art line?
PRIOR to induction.
55
**Lateral wall ischemia**: Which leads will show ST elevation and which coronary artery is likely affected?
**_Circumflex_ branch of LCA**
**Leads**: I, aVL, V5, V6
56
Pulmonary artery catheter complications
* arrhythmias
* V fib, RBBB, complete heart block
* catheter knotting
* balloon rupture
* thromboembolism; air embolism
* pneumothorax
* ***_PA rupture_***
* ***_most dangerous complication of insertion_***
* infection (endocarditis)
* damage to cardiac structures (valves, etc.)
57
Should we suspect ischemia in the OR, is obtaining a 12 lead ECG likely going to be our first line of assessment?
**No**, with draping and the sterile surgical field, we *can* obtain a 12 lead, but this may be difficult.
## Footnote
*\*\*More likely to drop a TEE probe and assess for wall motion abnormalities as well as work on _supply and demand_\*\**
58
Actions to remedy a damped waveform.
* pressure bag inflated to 300 mmHg
* reposition extremity or patient
* verify appropriate scale
* flush or aspirate line
* check or replace module or cable
59
5 (but actually 6) principle indicators for ECG ischemia detection:
1. ST segment elevation, \> or = 1 mm
2. T wave flattening or inversion
3. Development of Q waves
4. ST segment depression, flat or downslope \> or = 1 mm
5. Peaked T waves
6. Arrhythmias
60
Is the 3 lead ECG placement adequate as standard ECG monitoring in the OR?
NO, _usually adequate_ for tracking HR, detecting R waves for synchronized direct-current shock in cardioversion, and detecting ventricular fibrillation.
INADEQUATE for diagnosing more *complex arrhythmias* or for *ST segement monitoring*.
61
Summary of CVP Waveform.
**_Waveform Componenent Phase of Cardiac Cycle Mechanical Event_**
## Footnote
a wave end - diastole atrial contraction
c wave early systole isovolumetric contraction
x descent mid systole atrial relaxation
v wave late systole systolic filling of atrium
y descent. early diastole. early ventricular filling
62
**Anterior wall ischemia**: Which leads will show ST elevation and which coronary artery is likely affected?
**LCA - left coronary artery (per slide)**
**More specifically, LAD**
**Leads**: V3, V4
63
INFO CARD
Proper ECG Placement and Vectors
64
**Triscuspid stenosis** - CVP waveform
Tall **a wave**
attenuation of **y descent**
65
**Respiratory variation during spontaneous or positive pressure ventilation** - CVP waveform
measure pressures at **end - expiration**
66
SpO2 accuracy is really reduced at a level lower than \_\_\_\_\_\_?
70-75%
67
If you have a sudden drop in ETCO2, what should you do immediately?
Check for a pulse!
\*\*An acute drop in ETCO2 in the most accurate and the quickest method of assessing perfusion\*\*
68
Axis deviation more negative than -30 degrees.
Left axis deviation
69
According to the AANA Standard 9: Monitoring and Alarms, how often do we document blood pressure, heart rate, and respiration for all anesthetics?
**at least every 5 minutes**
\*\*Note: Dr. OG states vitals are often pulled over more frequently with the use of computer charting nowadays\*\*
70
How many views of the heart can we get using the 5-lead ECG system?
**7** views of the heart *(adds anterior view)*
_Leads_: I, II, III, aVR, aVL, aVF, V lead
71
When clinically significant changes in *body temperature* are intended, anticipated, or suspected, we monitor and facilitate what?
Monitor body temperature
\*\*Use active measures to facilitate normothermia\*\*
72
Name a common hemodynamic event in which we can commonly see **ST segment depression**, *_especially_* in patients with significant, but stable coronary artery disease (CAD)?
tachycardia
73
List complications of a line monitoring.
* nerve damage
* hemorrhage/hematoma
* infection
* thrombosis
* air embolus
* skin necrosis
* loss of digits
* vasospasm
* arterial aneurysm
* retained guide wire
* peripheral neuropathy
* misinterpretation of data
* misuse of equipment
74
Describe a few ways to maintain vigilance in a long case when vital signs look like train tracks?
Remain engaged with the surgery/status of surgery.
Continuously scan the room, monitors, patient, tubes/drains, and anesthesia machine.
75
How does positive pressure ventilation increase left ventricular preload and reduce left ventricular afterlaod?
Positive pressure ventilation increases lung volumes, displacing blood contained within the pulmonary venous resevoir into the left heart chambers → **increasing left ventricular preload.**
Simultaneously, the increase in intrathoracic pressure **reduces left ventricular afterload.**
76
What is the MAP? How do we calculate?
Time weighted average of arterial pressure during a pulse cycle
SBP + 2(DBP)/3
**OR**
DBP + 1/3 (SBP-DBP)
77
Which two leads are the most sensitive leads to detect exercise-induced ischemia?
**V4** and **V5** (90 to 100% sensitivity)
78
Cardiac blood flow review: just for funzys.
79
Why do we use two wavelengths of light, 660 and 940 nm, for pulse oximetry?
At **660 nm**, light absorption is greater by dexoxygenated hemoglobin than oxygenated hemoglobin.
At **940 nm**, light absorption is greater by oxygenated hemoglobin than by deoxygenated hemoglobin.
80
Gain should be set at standardization. **1 mV** signal produces...
**10 mm** calibration pulse.
_Therefore, a 1 mm ST segment change is accurately assessed_
81
The cornerstones of monitoring are in our physical assessment. Describe the 3 types of key physical assements and give examples of important uses in the OR.
**Inspection, palpation, auscultation**
* Observing chest rise and fall & ausculation of breath sounds pre-op, after intubation, and when ventilatory parameters change
* **_direct_** palpation of a pulse when a monitor value is questionable
* direct observation of a beating heart during cardiac surgery or palpation of the aorta by the surgeon
* inspecting the surgical field for blood loss
* noting real time changes on the surgical field (i.e. color change of blood)
* observing urine output
* inspection of mucous membranes, skin color, and turgor
* hydration, oxygenation, and perfusion
* evaluating JVD
* pupillary response
82
What is transmural ischemia?
**ENTIRE** wall thinkness is involved from the _occlusion_, *endocardium* to *epicardium*.
83
Describe common uses of precordial or esophageal stethoscopes.
Pediatric setting, especially when there will be airway manipulation and the tube could become kinked or dislodged.
Also, common in monitoring for venous air embolism in high risk cases (neuro anesthesia, exposing dural sinuses, per Dr. OG)
\*\*very sensitive monitor for bronchospasm, airway obstruction, changes in HR/rhythm, continual assessment of heart tones and breath sounds\*\*
84
Describe the **"v"** wave of the CVP waveform.
* ***ventricular** ejection*
* which drives venous filling of the atrium
* occurs in *_late systole_*
* tricuspid valve still closed
* occurs just after T wave on ECG
85
The 3 lead EKG is inadequate for diagnosing more complex arrhythmias for which a _***true* V1 lead is necesarry,**_ to distinguish between:
* RBBB vs LBBB
* VT
* SVT with aberrant venricular conduction
86
What is the purpose of electrocardiogram?
* detect arrhythmias
* monitor heart rate
* via both **EKG** (_heart rate_) and **pulse oximetry pleth** (_pulse rate_)
* heart rate on EKG monitoring is detected by R-R intervals, updated/calibrated every 5-15 seconds → can get a lot of inaccuracies on heart rate because of these calculations by monitor → further emphasizes importance of relating **pulse oximetry** _pulse rate_ to **EKG** _heart rate_.
* detect ischemia
* detect electrolyte changes
* monitor pacemaker function
\*\*Be mindful of all factors in the OR that could have electrical interference with our EKG monitoring\*\*
87
Name some underlying abnormalities that may hinder ST segment analysis.
* hypokalemia
* digitalis
* Wolff - Parkinson - White sydrome
* LVH
* acute pericarditis
88
Because of the disadvantages known to placing left IJ catheters, how should we confirm placement in these scenarios?
Obtain xray to confirm tip placement
89
Describe the relationship between *oxygen* and *hemoglobin* with a **left** shift of the oxyhemoglobin dissociation curve. What are some conditions that would cause a **left** shift?
With a **left shift**, hemoglobin is going to bind more tightly to oxygen and be less likely to release oxygen to the tissues.
**Conditons**
* alkalosis
* hypocarbia
* hypothermia
* decreased 2,3 BPG
* carboxyhemoglobin
* fetal hemoglobin
90
Indications for PAP monioring.
* LV dysfunction
* valvular disease
* pulmonary HTN
* CAD
* ARDS/resp failure
* shock/sepsis
* ARF
* surgical procedure: cardia, aortic, OB (rare)
91
Is a CVC alone sufficient for large, volume fluid resuscitation?
**No**, *large bore peripheral IVs* are more sufficient for rapid, large volume fluid resuscitation
CVC can be used as adjunct for other purposes obviously
92
What conditions are needed to measure PPV (pulse pressure variation) accurately?
* _mechanical ventilation_ with tidal volumes of 8-10 ml/kg
* PEEP \> or = 5 mmHg
* regular cardiac rhythm
* normal intraabdominal pressure
* closed chest
93
When neuromuscular blocking agents are administered, what do we monitor and assess?
neuromuscular response to assess depth of blockade and degree of recovery
94
How do we measure pulse oximetry?
* Spectroscopy
* probe is composed of a light emitter and a photodetector
* Measures transmission of light through a solution to the concentration of the solute in the solution
* Application of Beer - Lambert Law
* Provides an estimate of SaO2 by differentiating light absorption by arterial blood from light absorption by other components
95
Which conditions/scenarios may preclude accurate pressure monitoring from *affected* sites?
* atherosclerosis
* arterial dissection
* stenosis
* embolism
* unusual patient positions during surgery
* may produce regional arterial compression
* surgical retraction
* can compromise perfusion and monitoring to a localized area
96
What is the most imporatnt life-threatening vascular complication of central venous catheterization?
**Cardiac tamponade** resulting from perforation of the intrapericardial super vena cava, right atrium, or right ventricle
* \*\*Injury was the 2nd most common complication related to central catheters reported in the American Society of Anesthesiologists Closed Claims Project in 2004\*\*
* 81% mortality in these claims
* often had delayed pressentation (1-5 days!)
97
**Pericardial constriction** - CVP waveform
Tall **a and v waves**
Steep **x and y descents**
M or W configuration
98
Describe palpation as a measurement of NIBP.
* palpating the return of arterial pulse while an occluded cuff is deflated
* **advantages**: simple, inexpensive
* **disadvantages**: meausures only SBP, underestimates SBP
* \*\*likely use this as a quick method when someone is hypotenisve\*\*
99
Name some causes of _inaccurate_ pulse oximetry readings.
* malposition of probe
* dark nail polish
* different hemoglobin
* dyes
* electrical interference
* shivering
100
Name a few mechanisms in which we can improve accuracy and system dynamics of our transducer set up.
* minimize tube length
* limit stop cocks
* no air bubbles
* using non compliant stiff tubing
* calibration at level of heart (mid-axillary line/right atrium)
* calibration at meatus of ear/circle of Willis if concerned about cerebral perfusion as in sitting patient
101
INFO CARD
Square wave test
102
In the 5-electrode system, which two leads do we usually monitor and why?
**Lead II** - HR, and arrhythmia detection
**V5** - ischemia detection
103
A majority of modern patient monitoring systems do not simultaneously monitor all 12 ECG leads, how can we use our 5 lead system to benefit us, particularly in noncardiac surgery?
Intentionally select _chest leads_ to monitor for potential ischemia in particular leads if there is a known blockage or % blockage in a particular coronary artery.
104
Describe the relationship between *oxygen* and *hemoglobin* with a **right shift** of the oxyhemoglobin dissociation curve. What are some conditions that would cause a **right shift**?
With a **right shift**, hemoglobin is more likely to release oxygen to the tissues, so the tissues will be more oxygenated
**Conditions**
* acidosis
* hypercarbia
* hyperthermia
* increased 2,3 BPG
105
Complications of central venous catheters (CVC)
* More serious complications include:
* perforation into the pleural space of mediastinum
* hydrothorax
* hemothorax
* hydromediastinum
* hemomediastinum
106
List patient types that may be more vulnerable to complications of NIBP measurement and how can we mitigate these complications?
Patients with:
* peripheral neuropathies
* arterial or venous insufficiency
* severe coagulopathies
* recent use of thrombolytic therapy
\*Be mindful of **where** we place the BP cuff as well as **frequency** of inflation - someone who is stable probably does not need q1 or q3 min NIBP like they may have need for induction. Can switch back to q5min\*
107
Give a brief overview of the CVP waveform. How many phasic events? Peaks? Descents?
* 5 phasic events
* 3 peaks (a, c, v)
* 2 descents (x, y)
108
Complications of NIBP measurement.
* pain
* petechiae and ecchymoses
* limb edema
* venous stasis and thombophlebitis
* peripheral neuropathy
* compartment syndrome
109
What is your first duty as an anesthesia provider?
Vigilance
110
List insertion sites for CVCs
* left internal jugular vein
* right internal jugular vein
* subclavian veins
* external jugular veins (difficult to place)
* femoral veins
111
INFO CARD
Arterial Waveform Detail
112
1 square on the _horizontal axis_ of ECG recording = ? sec and ? mV
.04 sec
.1 mV
113
**Triscuspid regurgitation** - CVP waveform
tall systolic **c-v wave**
loss of **x descent**
114
Define Vigilance.
Sustained attention.
The ability of the observer to maintain their focus of attention and to remain alert to stimuli for prolonged periods of time.
115
Describe the disadvantages of placing a CVC or any catheters through the left side of the neck.
* the cupula (tip of the pleura) is higher on the left side than on the right → *theoretically, increased risk of pneumothorax*
* Thoracic duct may be injured as catheter enters the venous system at the junction of the left IJ and subslavian veins
* left IJ is often smaller
* more overlap with adjacent carotid
* has to traverse the inominate vein and enter the SVC perpendicular
* catheter tip may impinge on right, lateral wall of SVC, which can increase risk of vascular injury
116
In general, do we confirm placement of a CVC in the OR?
**No**
* we aspirate blood from all ports
* obtain XRAY after surgery
\*\*Likely will obtain XRAY in OR if catheter was placed on **left**\*\*
117
Which leads are the precordial leads?
V1-V6
118
Describe the **"y"** descent of the CVP waveform.
* diastolic decrease in atrial pressure
* due to flow across the open tricuspid valve into the ventricle
119
Where do we place precordial and esophageal stethoscopes?
**Precordial**: placed ON the chest surface (can be taped)
**Esophageal**: 28-30 cm INTO esophagus
120
Name 5 methods of **cardiac output monitoring** and note which one is the *most widely used clinical technique*.
* Thermodilution
* **\*\*Most common method\*\***
* can have some measurement errors based on rapid IV administration of fluid, shunts, and tricuspid regurgitation
* Continuous thermodilution
* Mixed venous oximetry
* Ultrasound
* Pulse Contour
121
Describe auscultation as a measurement of NIBP.
* Obtain using a sphygmomanometer, cuff, and stethoscope; Korotkoff sounds heard due to turbulent flow within an artery created by mechanical deformation from BP cuff
* **advantages:** permits estimation of SBP and DBP
* **disadvantages**: unreliable in patients with HTN - usually lower
122
Which electrode monitoring system is currently the standard for monitoring patients with suspected perioperative myocaridal ischemia?
5-electrode monitoring system
123
Name 5 different types of Non-Invasive Blood Pressure Management
* Palpation
* Doppler
* Auscultation
* Oscillometry
* Coninuous NIBP finter readings
124
Define underdamped waveform and list potential causes.
Systolic pressure overshoot and additional small, nonphysiologic pressure waves distort the waveform making it hard to discern the dicrotic notch.
Potential causes:
* catheter whip or artifact
* stiff non compliant tubing
* hypothermia
* tachycardia or dysrhythmia
125
Describe lead placment for 3-Lead ECG.
Electrodes: RA, LA, LL
Leads: I, II, III
3 views of heart (no anterior view)
126
Describe **pulsus parvus** and **pulsus tardus** and they're associated *condition*.
**pulsus parvus**: narrow pulse pressure
**pulsus tardus**: delayed upstroke
aortic stenosis
127
The overall complication risk for a *radial a line* is **low.** Which kinds of scenarios put patients at *_increased_* risk for complications?
* vasospastic arterial disease
* previous arterial injury
* thrombocytosis
* protracted shock
* high dose vasopressor administration
* prolonged cannulation
* infection
128
Systolic left ventricular failure will have an arterial waveform characteristic of?
**pulsus alternans**: alternating pulse pressure amplitude
129
When we have unreliable or inaccurate pulse oximetry readings (SpO2), what else can we use to obtain accurate SaO2 readings as well as measures of other hemoglobins?
Co-oximetry
## Footnote
**\*\*Co-oximetry is consdiered the gold standard for SaO2 measurements and is relied on when pulse oximetry readings are inaccurate or unobtainable\*\***
130
In a patient with an underlying ECG abnormality that makes ST segment analysis difficult, what is another modality for diagnosis of myocardial ischemia?
Transesophageal echocardiography (TEE)
131
Relate Ohm's law (V=IR) to blood pressure.
**V** (blood pressure) = **blood flow** (cardiac output) multiplied by **resistance** (systemic vascular resistance)
132
On the vertical axis of EKG recording, ? mm = ? mV.
10 mm = 1 mV
133
Explain in detail, why it is important to assess baseline ST segments and set ST segment alarms accordingly, *especially* in patients with _CAD_.
Many patients with CAD do not have perfectly isoelectric ST segments (**they're baseline is already off!**)
Tailoring the ST segment alarm paramters to the patient's baseline ST segment level is important becasuse if alarm parameters are set 1 - 2 mm around isoelectric (0 mV) line rather than at the patient's baseline ST segment level, false alarms will frequently occur.
i.e. A patient may alarm at 4 mm ST depression. While concerning, this makes a huge difference if they're baseline was already 3 mm depression vs. baseline 0 mm.
134
Indications for arterial cannulation for BP monitoring.
* continuous, real time blood pressure monitoring
* planned pharmacologic or mechanical cardiovascular manipulation
* repeated blood sampling
* failure of indirect arterial blood pressure measurement
* supplementary diagnostic information from the arterial waveform itself
* elective deliberate hypotension
* wide swings of intra-op BP
* risk of rapid changes in BP
* rapid fluid shifts
* titration of vasoactive drugs
* end organ disease
135
How will your SpO2 levels read when you have carboxyhemoglobinemia (carbon monoxide poisoining)? Why?
**Falsely high;**
Carboxyhemoglobin and oxygenated hemoglobin absorb light at the same frequency (660 nm). At 940 nm, COHb absorbs virtually no light. Thus, in a ptient with carbon monoxide poisoning, the SpO2 is falsely elevated.
However, patient will be *_hypoxic_* if you draw an ABG.
136
If you do infact have ST segment **elevation** related to coronary artery thrombosis, you are likely to see reciprocal ST segment **depression** in which leads?
contralateral leads
137
INFO Card
Standard Chest Lead Electrode Placement
138
In an arterial waveform, **spike and dome** (mid systolic obstruction) is associated with which type of condition?
HCM-hypertrophic cardiomyopathy
139
Why should we use diagnositc mode on our EKG filtering capacity?
Filtering out the low end of frequency bandwidth can distort ST segment.
"We see more 'noise,' but have a better diagnositic"
\*Other modes include *filter mode* and *monitor mode*\*
140
Relative contraindicaitons of PA cath insertion
* Wolff Parkinson White syndrome
* LBBB
141
Normal oxygen consumption (mL/min)
200 - 250 mL/min (*average*: 225 mL/min)
142
Name the 5 types of monitoring required according to the AANA Documenting Standards: Monitors.
* Electrocardiogram (EKG) (Cardiovascular)
* Blood Pressure (Cardiovascular)
* Temperature (Thermoregulation)
* Pulse Oximeter (Oxygenation)
* End-tidal CO2 (Ventilation)
143
INFO CARD
Table of Normal Values
144
**A fib** - CVP waveform abnormality
loss **a wave** (no atrial kick)
prominent **c wave**
145
Compared with central aortic pressure, peripheral arterial waveforms have:
* higher systolic pressure
* lower diastolic pressure
* wider pulse pressures
146
Why is the 3 lead EKG system inadequate for ST-segment monitoring?
Does not provide *multilead monitoring* or *_precordial leads_*, which are often most sensitive for detecting ischemia.
147
How does decreasing HR help to remedy ST segment depression related to tachycardia?
Increases time in diastole (ventricular relaxation/filling) → improves coronary perfusion pressures
148
Describe the **"c"** wave of the CVP waveform.
* atrial pressure decreases after the "a" wave as a result of atrial relaxation
* the **"c"** wave is due to isovolumetric contraction; *tricuspid valve **closes***, bulging back into the right atrium
* occurs in *_early systole_* (after the QRS on ECG)
149
Describe the **PCWP** (pulmonary capillary wedge pressure) waveform.
* **"a" wave**
* respresents *contraction of the left atrium*
* normall a small deflection UNLESS there is resistant in moving blood into the left ventricle (i.e _mitral stenosis_)
* **"c" wave"**
* due to a rapid rise in the left ventricular pressure in *early systole*, causing the *mitral valve to bulge backward into the left atrium,* so that the atrial pressure increases momentarily
* _(mitral valve bulges back with isovolumetric contration)_
* **"v" wave**
* produced when blood enters the left atrium during *late systole*
* **prominent "v" wave** reflects *mitral insufficiency* causing large amounts of blood to reflux into the left atrium during systole
* can have mitral regurge and have a lot of reflux into the left atrium
150
What is a pulmonary artery catheter and what data can we gather PAP monitoring?
* right sided heart catheter used for direct bedside assessment of:
* intracardiac pressures
* CVP, PAP, PCWP/PAWP
* estimate LV filling pressures
* Assess LV function
* CO
* Mixed venous oxygen saturation
* PVR and SVR
* Pacing options
151
List 2 uses of pulse oximetry and appropriate sites.
**Uses**
1. detection of hypoxemia
2. detection of perfusion
**Sites**
* fingers
* toes
* nose
* ear
* tongue
* cheek
152
Describe an arterial line.
Percutaneous arterial catheter transduced to convert the generated pressure into an electrical signal to provide a waveform.
* generates real - time beat to beat BP
* allows access for arterial blood samples
* measurement of CO/CI/SVR (based on algorithms)
153
Axis deviation higher than +90 degrees
Right axis deviation
154
Which two arterial waveforms more closely resemble aortic pressure than do waveforms from peripheral sites?
Axillary and femoral
155
How does transmural ischemia present on EKG and what are two primary causes?
_ST elevation_ *with* OR *without* positive (hyperacute) T waves.
Result of **acute coronary artery occlusion** by:
**(1)**: coronary thrombosis
**(2)**: vasospasm (Prinzmetal variant angina)
156
List the 5 electrodes for the 5 lead ECG system and the leads monitored.
Electrodes: RA, LA, LL, RL, chest lead
Leads: I, II, III, aVR, aVL, aVF, V lead
157
Name some ways that we can decrease O2 demand when we notice ST depression in the OR?
Decrease HR
Increase BP
Decrease catecholamines
158
For which cases do we monitor end tidal CO2?
ALL anesthesia cases including moderate sedation, deep sedation or general anesthesia.
159
Normal mixed venous oxygen saturation
70 - 80% (*average*: 75%)
160
What is the phlebostatic axis and what positions is it relevant for?
4th intercostal space, mid axillary line
relevant for supine and up to 60 degrees of head up tilt
161
Name scenarios where you may obtain falsely **low** BP.
* cuff too large
* extremity above level of heart
* poor tissue perfusion
* too quick deflation
162
When performing *transesophageal echocardiography,* what
**7 cardiac parameters** are observed?
* ventricular wall characteristics and motion
* valve structure and function
* estimation of end-diastolic and end-systolic pressures and volumes (EF)
* CO
* blood flow characteristics
* Intracardiac air (look for)
* Intracardiac massess (look for)
163
What is perfusion pressure?
Pressure difference across the circulation of _any organ_ → the pressure on the *upstream side* of that system **minus** the pressure on the *downstream side*
164
How do we typically define *intraoperative hypotension* for adults? Why?
MAP of 55-60 mmHg
MAPs \< ~50 mmHg and \< 60 mmHg for as short as 5 and 10 minutes, respectively, were associated with an increased 30 day postop mortaility rate.
165
What does the ST segment represent on ECG?
myocardial repolarization (relaxation)
## Footnote
**ECG component most sensitive to acute myocardial ischemia.**
166
Normal values for systemic vascular resistance and pulmonary vascular resistance.
**SVR**: 800-1600 (*average*: 1200 dynes-sec-cm-5)
**PVR**: 40-180 (*average*: 80 dynes-sec-cm-5)
167
**Atrioventricular dissociation** - CVP waveform
cannon **a wave**
