CV Monitoring Flashcards
Mean Arterial Pressure (MAP)
[systolic + 2(diastolic)]/3
Pulse Pressure
Systolic - Diastolic
ratio of changing height away from heart to correlation of pressure
10 cm H20 = 7.5 mmHg
Non-invasive BP techniques
- Palpation = only assess systolic BP
- Doppler = only systolic but with probe
- Auscultation = USELESS
- Oscillometry = preferred mode, with automated cuff
- Tonometry = probe senses pressure required to occlude artery
Oscillometry
Inflate past systolic –> pulsations are then transmitted at systolic as it deflates
- Maximum oscillations are the MAP and diastolic is calculated
Incorrect cuff readings
Small cuff = abnormally high BP
Large cuff = abnormally low BP
Arterial line sites
Radial = superficial, reliable, substantial collateral Ulnar = deeper, more tortuous Brachial = larger, more accurate pressure Femoral = more arterial disease and possible pseudoaneurysm, infection risk DP/PT = only in a pinch
Arterial line indications
- anticipated hypotension requiring vasoactives
- wide fluctuations in BP during case
- multiple lab draws
- anticipated bleeding
Complications of arterial lines
- hematoma
- bleeding
- vasospasm
- thrombi/emboli
- air bubble
- pseudoaneurysm
- necrosis of skin
- infection
- nerve damage
Factors that increase risk of complication of arterial line
- prolonged cannulation
- hyperlipidemia
- multiple attempts
- larger catheters
Hyperresonance of arterial waveform
artifact that is caused by reverberation of the pressure waves within the system
Piezoelectric effect
converts the mechanical strain of pulsation into electrical energy seen on the monitor
ECG
mandatory monitor, continuous from beginning to end
Leads of ECG
II = axis at 60 degress, parallel to atria (P waves)
- most sensitive for arrhythmias
V5 = most appropriate in the 5th intercostal space
- anterior and lateral wall ischemia
Indications for CVC
- monitor CVP
- Anticipate lots of fluid administration
- Anticipate or known pressor administration
Contraindications for CVC
- Tumor
- Clots
- Severe Tricuspid Regurgitation
Techniques of confirming venous placement of CVC
- transduce vessel
- blood color
- U/S
- pulsatility
- PaO2
Risks of CVC placement
- Infection (sterile technique)
- Hematoma
- Hydrothorax
- Pneumothorax
- Arterial Puncture (don’t dilate)
- Air embolus
- Cardiac Perforation
- Arrhythmia
- Hemothorax
- Tamponade
Optimal placement of CVC
at the tip of the SVC - RA junction
Pulmonary Artery Catheter
you can measure the CO and well as PA pressures with PA catheter
- can estimate LVEDP
Low SV and low LVEDP on PA Catheter
Hypovolemia
Low SV and High LVEDP on PA catheter
fluid overload
High SV and hypotension
vasoplegia
Contraindications to PA catheter
pre-existing LBBB
WPW
Inserting PA catheter
- Place into R atrium (15-20 cm) -> inflate balloon
- Sudden increase in systolic = R ventricle
- Sudden increase in diastolic = PA
- Equilibration of pressure = PA occlusion pressure
Complications of PA catheters
- CVC bacteremia
- Thrombogenesis
- PA rupture
- Valve Damage
- Endocarditis
- PA Infarct
- Hemorrhage
- Arrhythmia
Measuring Cardiac Output
Thermodilution = inject volume of cold saline
- change of temp at thermistor correlates to CO
- lots of temp change = low flow and CO
- no temp change = high flow and CO
Fick Principle for O2 consumption
CO = Vo2/ CaO2 - CvO2
