Cardiac monitoring and cardiac drugs Flashcards
Indications for 5-lead EKG
-Diagnosis of dysrhythmias
-Diagnosis of ischemia
-Diagnosis of electrolyte disturbances
-Monitor effect of cardioplegia during aortic cross-clamp
What single lead is best to monitor the LV?
V5
Positioned along the anterior axillary line in the fifth intercostal space
90% of ischemic episodes will be detected by ECG if which 2 leads are viewed?
Lead II and V5
Subendocardial ischemia results in:
ST segment depression
transmural myocardial ischemia is detected as:
ST segment elevation
Coronary perfusion occurs when in the RV?
Systole and diastole
Coronary perfusion occurs when in the LV?
Diastole only
Mechanically the_________ is subjected to higher pressures than the_______
endocardium
epicardium
Arterial catheter indications:
-CT/CV surgery
-Major vascular
-Neurosurgery
-trauma
-Major abdominal
-solid organ transplant
-acid-base/electrolyte monitoring
-Dysrhythmias
-Marked obesity
-CPB
-LVAD
BP is measured at the level of the transducer which is where?
Level of Right atrium
On the arterial wave form, what does the area under the curve represent?
MAP
Dicrotic notch=
closure of aortic valve
Hypovolemia is suggested by a decrease in _____ ______ ____ with positive-pressure ventilation (pulsus paradoxus).
arterial systolic pressure
Respiratory variation of what 3 things can be used as goal-directed parameters to identify patients who will respond to fluid administration
arterial sBP
stroke volume (SV)
pulse pressure
Overdamped:
falsely underestimates systolic BP and overestimates diastolic BP
Underdamped:
falsely overestimates systolic BP and underestimates diastolic BP
How many oscillations during a square wave test will an optimally damped aline produce?
1-2
How many oscillations during a square wave test will a underdamped aline produce?
> 2
How many oscillations during a square wave test will an overdamped aline produce?
< 1.5
Factors for over dampened arterial waveform
Air within a catheter or transducer causes most pressure monitoring errors.
-Friction in the fluid pathway
-Bubbles in the tubing
-Clots in the tubing
-Vasospasm
-Long, narrow tubing (i.e. extensions added)
-Compliant tubing
make sure that pressure tubing is used if extension is required (do not use IV extension tubing)
Factors for under dampened arterial waveform
Catheter whip or artifact
Stiff non-compliant tubing
Hypothermia
Tachycardia or dysrhythmia
Factors for under dampened arterial waveform
Catheter whip or artifact
Stiff non-compliant tubing
Hypothermia
Tachycardia or dysrhythmia
Contraindications for a CVC
(a)Presence of significant carotid disease
(b)Recent cannulation of the IJ (with the concomitant risk of thrombosis)
(c)Contralateral diaphragmatic dysfunction
(d)Thyromegaly or prior neck surgery
What is the most common access route for CVC placement?
Internal Jugular (right)
What are the locations you can put a CVC?
The IJ veins,
subclavian (SC) veins,
femoral veins
Blood flowing away from an ultrasound transducer is
BLUE
Blood flowing toward an ultrasound transducer is
RED
Disadvantage of using the subclavian vein for CVC placement?
Subclavian vein cannulation carries the highest rate of pneumothorax of any approach.
What is a risk of left sided subclavian vein CVC placement?
the thoracic duct may be lacerated
What approach is recommended as the first option for a PAC placement?
Right IJ
Distance to the junction of the vena cava and RA from subclavian
10cm
Distance to the junction of the vena cava and RA from Right IJ
15cm
Distance to the junction of the vena cava and RA from Left IJ
20cm
Distance to the junction of the vena cava and RA from femoral vein
40cm
Distance to the junction of the vena cava and RA from right median basilic vein
40cm
Distance to the junction of the vena cava and RA from left median basilic vein
50cm
Tip of CVP catheter should be placed just above what?
junction of vena cava and RA
Tip of PA catheter should be placed where?
pulmonary artery
Distance from right IJ to Junction of vena cava and RA
15cm
Distance from right IJ to right atrium
15-25cm
Distance from right IJ to right ventricle
25-35cm
Distance from right IJ to pulmonary artery
35-45cm
Distance from right IJ to pulmonary artery wedge position
40-50cm
Complications while floating a PA/Swan
Dysrhythmias while obtaining access
Floating PA catheter:
-Pulmonary artery rupture
-Dysthymias
-RBBB –>complete HB (DO NOT float a PAC into a patient with LBBB, advancing to RV can cause RBBB leading to complete HB)
What does the central venous pressure (CVP) measure
right atrial pressure
What does the CVP act as a predictor of?
Pt preload and volume status
Normal CVP range
1-10
what is CVP a good indicator of?
- Intravascular volume
- Venous tone
- RV compliance
** not a good indicator of fluid status
A wave
Right atrial contraction
just after P wave (atrial depolarization)
C wave
Right ventricular contraction
Just after QRS (ventricular depolarization) (in line w S)
closure of the tricuspid valve
X descent
Right atrial relaxation
ST segment
X descent
Right atrial relaxation
ST segment
V wave
passive filling RA
Just after T wave begins ( ventricular repolarization)
(coincides with part of RV systole)
Y descent
RA empties through open TV
After T wave
Loss of a waves/only v waves:
Atrial fibrillation
Ventricular pacing in the setting ofasystole
A wave occurs when synchronized contraction of RA is lost
Giant/ “cannon” a waves:
Junctional rhythms
Complete AV block
PVCs
Ventricular pacing
Tricuspid or mitral stenosis
Diastolic dysfunction
Myocardial ischemia
Ventricular hypertrophy
atria contracts and empties against a high resistance (either @ valve or noncompliant ventricle)
Large V waves:
Tricuspid regurgitation
Acute increase in
intravascular volume
RV papillary muscle ischemia
tricuspid regurg allow a portion of the RV volume to pass through a closed but incompetent tricuspidvalve during RV systole. This increases pressure and volume in the right atria = large V wave (C +V waves may blend together)
High CVP value:
RV failure
Tricuspid stenosis OR regurgitation
Cardiac tamponade
Constrictive pericarditis
Pericarditis
Volume overload
Pulmonary HTN
PEEP
Transducer below phlebostatic axis
Low CVP value
Hypovolemia
ARDS
Transducer above phlebostatic axis
CVP should be zeroed at the:
phlebostatic axis (4th intercostal space mid anteroposterior level)
CVP should be measured at
end expiration
PAC normal systolic value
Systolic: 20-30 mmHg
PAC normal diastolic value
8-12 mmHg
where should the tip of the PAC be?
Zone 3 = continuous blood flow
-Provides most accurate estimate of LVEDP
Causes of high PA pressures
LV failure
Mitral stenosis or regurgitation
L-R shunt
ASD or VSD
Volume overload
Pulmonary HTN
Catheter “whip” catheter may be coiled or advanced too far
Causes of low PA pressures
Hypovolemia
May see with RV failure
May see with tricuspid regurgitation or stenosis
What is the pulmonary artery wedge pressure or PAOP measuring?
left ventricular end-diastolic pressure (LVEDP)
Why is a PAOP not commonly monitored?
due to increased risk of vessel rupture when wedging is performed incorrectly/catheter is not in the ideal position
Normal PAOP value
8-12 mmHg
Or 5-15
what else can you use to estimate a wedge pressure?
PAD
what else can you use to estimate a wedge pressure?
PAD
Causes of a high wedge pressure
LV failure
Mitral stenosis or regurgitation
Cardiac tamponade
Constrictive pericarditis
Volume overload
ischemia
Causes of a low wedge pressure
Hypovolemia
RV failure
Tricuspid regurgitation or
stenosis
Pulmonary embolism
normal CO
5-6 L/m
normal CO
5-6 L/m
How many injections should you do for accuracy of CO measurement via thermodilution method?
3
The area under the curve is _______ proportional to cardiac output
INVERSELY
Overestimates of CO using thermodilution
Low injectate volume
Injectate that is too warm
Thrombus on the thermistor of the PA catheter
Partially wedged PA catheter
Underestimates of CO using thermodilution
Excessive injectate volume
Injectate solutions that are too cold
Where do you need blood returning from to measure a SVO2 (mixed venous oxygen saturation)
SVC
IVC
coronary sinus
3 samples mix in pulmonary artery
Normal SVO2
mal SVO2 = 65-75%
SVO2 decrease caused by increased O2 consumption:
Stress
Pain
Thyroid storm
Shivering
Fever
Seizure
SVO2 decrease caused by decrease o2 delivery
↓ Pao2
↓ HBG
↓ C.O.
SVO2 increased d/t decreased o2 consumption
Hypothermia
Cyanide toxicity-(SNP, sepsis,
left to right shunt)
SVO2 increased d/t increased o2 delivery
↑ Pao2
↑ HBG
↑ C.O.
Indications for TEE
-Identify systolic wall motion abnormalities (SWMA) and vascular aneurysms
-calculation of EF
-ventricular preload
-measurement of blood flow within the heart and across the valves
TEE probe is placed in the esophagus to a depth of?
approx. 35-40 cm from teeth
Posterior structures are displayed at_____ and anterior structures ______of the screen
top of screen
at the bottom
Best single view for routine monitoring SWMA
Short axis at midpapillary level
TEE is the gold standard for assessing what?
myocardial function
What does SOAP stand for?
Suction, oxygen (and other gases), airway equipment, pharmacy
other monitors:
cerebral oximetry
BIS monitor
TEE
Istat
Pts with HTN will display an exaggerated response to:
induction agents (more HoTN) and laryngoscopy (more extreme HTN)
Administering _______ or _______can decrease the hyperdynamic sympathetic response to laryngoscopy
beta blockers
arterial dilators (nitro)
Why would you use lidocaine IV prior to intubation?
Blunt laryngeal reflex with intubation
Predictors of hypotension during induction:
are age >50
ASA 3-4
baseline MAP <70
coadmin of high doses of fentanyl
metabolism for etomidate
ester hydrolysis
What does etomidate act as to increase the BP?
Alpha 2B adrenoceptor agonist
what does etomidate inhibit?
11b hydroxylase–> leads to adrenocortical suppression bc it’s essential in the body’s production of corticosteroids and mineralcorticoids
The effects of a single etomidate dose can last for how many hours?
72 hours
etomidate can cause increases in morbidity and mortality in patients who are:
on prior corticosteroid therapy and/or patients in a septic state
When is etomidate contraindicated?
Known sensitivity
Adrenal suppression
acute porphyrias
What is acute intermittent porphyria?
metabolic disorder caused by deficiencies in the enzymes that produce heme (building block of hemoglobin)
Most common symptoms of acute intermittent porphyria?
abdominal pain
N/V
MOA of ketamine:
noncompetitive NMDA antagonist
inhibits glutamate;
depressant effect on thalamic nuclei —> this blocks afferent signals of pain perception to the thalamus and cortex
MOA of ketamine:
noncompetitive NMDA antagonist
inhibits glutamate;
depressant effect on thalamic nuclei —> this blocks afferent signals of pain perception to the thalamus and cortex
What does ketamine inhibit?
tumor necrosis factor alpha:
may be responsible for its anti-inflammatory and antihyperanalgesic effects
what is the active metabolite of ketamine? What is it’s active percentage?
Norketamine (20-30%)
what kind of waves does ketamine cause on EEG?
theta
How can you combat the increasing effect ketamine has on on CBF, CMRO2 and ICP?
administer GABA agonist
Primary effects of Precedex are
sedation
analgesia
anxiolysis
reduced post-op shivering and agitation
CV sympatholytic actions
What will happen if you bolus dexmedetomidine too fast?
HTN and tachycardia
*Mu effects
Respiratory depression
bradycardia
sedation
euphoria
miosis (pupillary constriction)
urinary retention
N/V
pruritus
*Delta effects
Respiratory depression
urinary retention
pruritus
Kappa effects
Possible respiratory depression
sedation
dysphoria (state of unease)
hallucinations
delirium
miosis
diuresis
anti-shivering
complications of vasopressin
GI ischemia
decreased cardiac output
digital necrosis
cardiac arrest at elevated doses
*Which med causes increased coronary artery perfusion due to increase in diastolic BP
norepinephrine
Which med is typically a first line pressor when needed in a cardiac case?
Norepinephrine
MOA for dobutamine
*Primarily a beta 1 agonist with some B2 effects
what is the indication for dobutamine
increase CO/CI esp when coming off pump
Milrinone MOA
*phosphodiesterase 3 inhibitor;
prevent the breakdown of cAMP
What does milrinone decrease?
preload AND afterload
What does Hemoptysis while floating a swan indicate?
PA RUPTURE
insertion site with the highest risk of injuring thoracic duct
Left IJ
(can happen w left subclavian)
what is the risk of inserting a swan in the subclavian?
pneumothroax
why is LBBB a contraindication for PA catheter
RBBB= complete heart block
CVP should be measured at:
4th ICS mid anteroposterior level (phlebostatic axis)