Monitoring the Cardiovascular Patient Flashcards
What is one of the primary responsibilities of an anesthesiologist ?
Act as a guardian for the anesthetized patient ?
Review slide -4
What is the definition of monitoring ?
Continuous or repeated observation + vigilance in order to maintain homeostasis
List the 4 ASA standards of monitoring
I. Qualified personnel
II.Oxygenation: SaO2, FiO2
III. Ventilation: ETCO2, stethoscope, disconnect alam
IV. Circulation: BP, pulse, ECG
**Other monitors: Temp Peak airway pressure, Vt, ABG
What are modalities in the OR?
- Arterial Line
- Systolic Pressure Variation
- CVP
- PAC
- Cardiac Output
- Mixed Venous O2
What are the five indications for an arterial line?
1-Rapid moment to moment BP changes
2- Frequent blood sampling
3- Circulatory therapies: bypass, IABP, vasoactive drugs, deliberate hypotension
4- Failure of indirect BP: Burns, morbid obesity
5- Pulse Contour Analysis, SPV, SV
What steps do we need order to place a radial artery catheter?
Good collateral circulation
*Allen’s test
Uncommon, however what complications can we see with a radial artery line placement that are not?
- Vasospastic disease
- Prolonged shock
- High dose vasopressors
- Prolonged Cannulation
What are alternative arterial line sites ?
1-Brachial
—use a longer catheter to traverse elbow joint
–postop keep arm extended
–collateral circulation not as good as hand
2-Femoral
–use guide-wire technique
–puncture femoral artery below inguinal ligament ( easier to compress if required)
How do we calculate systolic pressure variation(SPV)?
Difference between maximal + minima values of systolic BP during PPV
-Normal ~ 5 mmHg due to decrease venous return
What SPV value do we use to predict hypovolemia?
SPV >15mmHg
or down > 15mmHg
What does PulseCO SPV + SV do for us as providers?
1-Predicts SV increase in response to volume are cardiac surgery and in the ICU
2- Similar estimates of preload v. echo during hemorrhage
3-Helpful in dx of hypovolemia after blast injury
4- Limitations: AI, arrythmias,
*Required mechanical ventilation
What are the seven indication of central venous line?
1-CVP monitoring
2- Advanced CV disease + major operation
3- Secure vascular access for drugs: TLC
4- Secure access for fluids:introducer sheath
5- Aspiration of entrained air: sitting craniotomies
6- Inadequate peripheral IV access
7- Pacer, Stanz Ganz
What are the steps for a central venous line placement in the right IJ?
A. IJ vein lies in grove between sternal and clavicular heads of sternocleidomastoid muscle
B. IJ vein is lateral + slightly anterior to carotid
C.Aseptic technique, head down
D. Insert needle towards ipsilateral nipple
E. Seldinger method: 22G finder, 18G needle, guidewire, scalpel blade, + catheter
F. Observe ECG, maintain control of guidewire
G. US guidance, CXR post insertion
What are the advantages to a RIJ central line placement?
- Consistent, predictable anatomic location
- Readily identifiable landmarks
- Short straight course to SVC
- Easy intro access for anesthesiologist at patients head
- High success rate , 90-99%
What are the alternate sites to central line placement?
- Subclavian
- -Easier to insert vs IJ if in C-spine precautions
- -Better patient comfort vs IJ
- -Risk pneumo- 2%
- External Jugular
- -easy to cannulate if visible, no risk of pneuno
- -20% cannot access central circulation
- Double Cannulation of the same RIJ
- Serious complications: vein avulsion, catheter entanglement, catheter fracture
What does CVP monitoring provide for us?
A-Reflects pressure at junction of vena cava+ RA B-CVP is driving force for filing RA + RV C- CVP provides estimate of --intravascular blood volume --RV preload D-Trending CVP is useful E. Measure at END- EXPIRATION F.Zero at mid axillary line
What do pulmonary catheters allow ?
- Allows for accurate bedside measurement of important clinical variables: CO, PAP, PCWP, CVP to estimate LV filling volume + guide fluid/ vasoactive drug therapy
- Discloses pertinent CV data that cannot be accurately predicted from standard signs symptoms
PA waveform pressures?
Slide 26
What are the indications for a PAC by the ASA task force?
- High risk patient with severe cardiopulmonary disease
- Intended surgery places patient at risk because of magnitude or event of operation
- Practice setting suitable for PAC monitoring: MD familiarity, ICU, nursing
- PAC education project
What are PAC outcomes?
- Early use of PAC to optimize volume status, and tissue perfusion may be beneficial
- PAC is ONLY a monitor, it cannot improve outcome if disease has progressed too far, or if intervention based on PAC is unsuccessful or detrimental
- Many confounding factors: learning’s bias, skill knowledge, usage patterns, medical v surgical illness
What are pulmonary artery complications?
- Minor 50% eg: arrhythmias
- Transient RBBB- 0.9-5%
- -external pacer if pre-existing LBBB
- Misinformation
- Serious 0.1-0.5% : knotting , pulmonary infarction, PA rupture ( e.g. over wedge) ,endocarditis, structural heart damage
- Death 0.016%
Problems Estimating LV Preload ?
Review Slide 31
Cardiac output is an important feature of PAC, what does it allow calculation of ?
-DO2
How do you obtain CO on a PAC?
Thermodilution: inject fixed volume, 10 ml ( of room temp or iced D5W ) into CVP port at end-expiration+ measure resulting change in blood temp at distal thermistor
