Monitoring Flashcards
standard monitors
VOTC:
ventilation, oxygenation, temperature, circulation
cardiac surgery monitors in addition to standard
invasive BP, CVP, TEE, UOP, ABGs, neuromonitoring
Preload
- tension on LV wall after diastole
- LVEDP indirectly
- increased preload=increased SV
- determined by intravascular volume (determined by total body sodium-controlled by aldosterone), venous tone, and ventricular compliance
Contractility
- -hearts ability to generate force
- chemical event from intracellular calcium
afterload
- Tension on LV when aortic valve opens
- indirectly measured by SVR
- increased SVR=increased afterload and decreased SV
Arterial pressure monitoring
-ideal location
which artery?
US?
ideal location is acending aorta
-most common: radial (ulnar nerve supplies 90% of flow)
*US as rescue tecnique
reasons for arterial line
- major surgery with blood loss or fluid shifts
- CP bypass
- Aortic surgery
- need ABGs
- shock
- recent MI
- permissive hypotension
- hypotehtermic procedures
- trauma
- inotropic support
arterial line contraindications
- local infections
- coagulopathy
- vasooclusive disease (raynauds)
- harvesting sites
arterial line complications
- infection (most common with femoral)
- hematoma
- spasm
- thrombosis (long catheters for a long time)
- ischemia
Arterial line waveform
- systolic bp=peak
- diastolic=trough
- pulse pressure= peak-trough
- contractility= upstroke
- stroke volume= area under curve
- closure of aortic valve=dicrotic notch
CVP why to do it
- major surgery with fluid shifts and blood loss
- massive trauma
- ionotropic support
- electrolyte or metabolic conditions requiring frequent sampling
- TPN
- high risk air embolism
CVP contraindications
- SVC syndrome
- coagulopathy (relative)
- new pacer/aicd
- surgical site access
CVP waveforms
a wave=contraction of RA
c wave= closure of tricuspid (RV contraction)
v wave= passive filling of RA, ventricular systole
x decent-atrial diastole
y decent= opening of tricuspid
CVP waveforms and cardiac cycle
A wave= RA contraction (just after P wave)
C wave= RV contraction (bulging of tricuspid into RA) (Just after QRS)
x decent= RA relaxation (ST segment)
V wave= passive filling of RA (just after T wave-ventricular repolarization)
Y descent= RA empties through open tricuspid (after t wave)
Normal CVP
elevations due to?
1-10 mean=5 elevations due to: RV disease pulm HTn pulmonic stenosis TV disease (TR= tall v waves) tamponade restrictive cardiomyopathies hypervolemia
CVP insertion sites
- IJ- short, straight course
just under medial border of SCM (carotid is deeper and more medial)
*use ultrasound - EJ- valves, more difficult
3.SC- increased risk of pneumothorax, tamponade, aortic injury - basilic/cephalic- migrates with arm movement
- femoral- easiest (no US) higher infection rates
CVP complications
- infection
- hemorrhage (lungs deflated when inserting)
- VAE
- thrombosis
- nerve injury
- thoracic duct puncture
PA catheter indications,
measures directly and indirectly
*obtain hemodynamic parameters and check O2 delivery and demand
DIRECTLY:
CVP/RAP, RVP, PAP, PAOP, CO, mixed SvO2
INDIRECTLY:
SVR, PVR, CI, SVI, LVSWI, RVSWI, DO2, VO2
PA catheter contraindications
- severe tricuspid or pulmonic disease
- RA or RV mass
- tetralogy of fallot
- arrythmias
- LBBB
- new pacer wires (6 weeks)
- severe coagulopathy
PA catheter complications
- complete heart block
- endobronical hemorrhage
- pulm infarct
- catheter knotting
- valve damage
- thrombocytopenia
- thrombus
PA catheter indications
- pulmonary HTN
- cardiogenic shock
- mixed shock
- tamponade
- transplant
- mechanical complication of stemi (RV infarct, papillary muscle rupture, septal rupture)
*innapropriate (use non invasive): high risk surgery, septic shcok, heart failure, ARDS
PVR and SVR
-PVR= estimate of RV afterload. elevated in pulm htn
normal= 150-250
SVR= estimate of LV afterload. increased in LV wall stress
determinant of O2 consumption
normal=900-1400
distance to the junction of vena cava and ra from: subclavian RIJ LIJ femoral right median basilic left median basilic
subclavian: 10cm RIJ: 15cm LIJ: 20cm femoral: 40cm right median basilic: 40cm Left median basilic: 50cm
distance from RIJ to distal structures: Cavoatrial junction RA RV PA wedge
cavoatrial junction: 15 RA: 25-35 RV: 35-45 PA: 45-55 wedge: 50-60
Goal placement of PAC and details about zone
west lung zone III. bulk of pulmonary blood flow is in this region. provides most accurate estimate of LVEDP
zone III: arterial pressure >venous pressure>alveolus pressure
- *it is the DEPENDENT region of lungs
- base when sitting
- towards back when supine
- towards chest when prone
- towards dependent lung in lateral
*tip in zone I or II –> variations in PAOP, lost a and v waves, PAOP>PADP
Normal pressures: RA RV PA Wedge LA LVEDP
RA: 5 RV: 25/5 PA: 25/10 (quarter over dime) Wedge: 10 LA: 8 LVEDP: 8
PAOP waveforms
- a wave: LA systole
- c wave: LV systole- upward displacement of mitral valve into LA
- V wave: passive LA filling
distortion of CVP and PAOP waveforms
- no a waves
- giant a waves
- large v waves
- no a waves: a fib, ventricular pacing
- large a waves: junctional rhythms, complete heart block, diastolic dysfunction, tricuspid or mitral stenosis (atrium tries to contract against closed valve- tricuspid or mitral)
- large v waves- tricuspid or mitral regurg, acute increase in volume
increased CVP causes
- RV failure (back pooling)
- TS or TR
- cardiac tamponade (restricted ventricular emptying)
- constrictive pericarditis (restricted ventricular emptying)
- volume overload
- pulm HTN (backing up)
- LV failure
Elevated RV pressures
systolic and diastolic
-systolic: pulmonary issue causing RV to pump into stenotic vessel pulmonary HTN (high RA- >25 and high PA) Pulmonary stenosis (high RA, normal PA) PE
-diastolic: RV issues causing limited filling cardiomyopathy RV ischemia cardiac constriction tamponade RV failure
monitoring limitations
- CVP does not approximate PADP with change in RV compliance or tricuspid disease
- PADP does not approximate PAOP with pulm HTN, MR or AR, lung zone II or III, tachycardia, ARDS, RBBB
- PAOP does not approximate LAP with PEEP, lung zone II or III, mediastinal fibrosis, RBBB
- LAP does not approximate LVEDP with PEEP, mitral valve disease, change in LV compliance, pulm disease
- LVEDP does not approximate LVEDV with PEEP, change in LV compliance (ischemia)
pressures in LV failure
high CVP, high PADP, high PAOP
blood backing up through pulmonary circuit
pressures in RV failure
TS or TR
high CVP, normal or low PADP, normal or low PAOP
blood backing up systemically. unable to eject into pulmonary circuit
pressures in PE
high CVP, high PADP, normal or low PAOP
pressures in pulmonary HTN
high CVP, high PADP, normal PAOP
pressures in tamponade
high CVP, high PADP, high PAOP
pressures in LV ischemia or MR
normal CVP, high PADP, high PAOP
blood backing up into pulmonary circuit
pressures in ARDS
low CVP, high PADP, normal PAOP
pulse ox
- based on beer lambert law. 2 waves of light
- red light- preferentially absorbed by deoxyhemoglobin (higher in venous)
- near infrared light-preferentially absorbed by oxyhemoglobin (higher in arterial)
- need pulsatile flow
- at <60mmhg pao2 steep decline in SpO2
SVO2
normal= 65-75%
decreases when decreased O2 delivery or increased O2 consumption
ECGs
- 3rd degree block
- AV dissociation
- bundle branch blocks
- digitalis
- electrolytes (Ca, K)
- hypothermia
- pericarditits
- tamponade
- pneumo
- PE
- subarachnoid hemorrhage
- WPW
- 3rd degree: atria/ventricles beat independent, NO p wave conducted through
- AV dissociation: atria and ventricles beat independent, p wave IS conducted through
- bundle branch blocks: complete=QRS>.12, incomplete = QRS .10-.12
- digitalis: ST segment sloping
- hypercalcemia: increased PR, decreased QT
- hypocalcemia: increased QT
- hyperkalemia: increased QT, peak t wave
- hypokalemia: u wave
- hypothermia: bradycardia, prolonged PR and QT
- pericarditis: diffuse ST and T wave changes
- tamponade: low voltage p wave
- pneumo: right axis deviation, decreased QRS amplitude, inverted T waves in V1-V6
- PE: Q waves in III and AVl
- subarachnoid: t wave inversion, prominant U waves, bradycardia
- WPW: short PR interval, wide QRS * avoid digoxin (increases conduction through bundle of kent)
ischemia on ECG
- earliest sign
- depolarization order
- earliest deterction intraop is from TEE (see diastolic dysfunction first)
- earliest sign on ECG is iso-symmetrical t-waves in 2 leads
- J point elevation 0.1 or hihger in any lead (except V2, V3) required for STEMI in 2 or more contiguous
- ventricular depolarization goes endocardium to epicardium (in to out)
- ST elevation correlates with offending vessel. can have depression in recipricol leads
- typically see ST elevation, t wave increase, presence of Q waves
inferior MI (second most sensitive)
II, III, aVF
RCA
Posterior
recipricol changes in V1-V4 (dont monitor posterior)
R waves, ST and T depression
Left cirfumflex
Lateral (most sensitive)
I, aVL, V5, V6
left circumflex
anterior
V3, V4
LAD
septal
V1-V4
LAD
EEG
laws
postsynaptic APs of cortical neurons
- EEG amplitude and frequency are inversely related
- simultaneous decrase indicates hypothermia, ischemia, anoxia, or excessive hypnosis
- simultaneous increase indicates seizure or artifact
eeg waves
beta- awake
alpha-moderate sedation
-theta-general anesthesia
-delta-deep anesthesia
BIS
40-60=general anesthesia
transcranial doppler
US waves transmitted through temporal bone
jugular bulb oximetry
measures cerebral venous sat through catheter
55-70%=normal
global measurement (cant detect focal ischemia)
cerebral oximetry
- noninvasive. uses infrared light
- non pulsatile (use for CPB)
- normal = <20% of baseline
coagulation in bypass
CPB produces massive inflammatory response-activates clotting cascade use heparin
heparin
binds to antithrombin III and increases efficacy. (non functional if low endogenous antithrombin III). inhibits factor x –> inhibits prothrombin–> thrombin
protamine reversal
1mg protamine reverses 100 units of heparin
protamine can cause anaphylaxis- hypotension, right HF, pulm edema, platelet inhibition
ACT
normal=80-120
CPB= 300-400
aPTT
intrinsic and final
normal 28-32
PT
extrinsic and final
normal 12-14
guide coumadin
heparin resistance
due to competitive antagonism, need to increase dose
HIT
autoimmune reaction. platelet consumption forming clots but still bleeding. usually 5-14 days after heparin
TEG
looks at integrity of platelets and clotting cascade to evaluate clot strength and ability to maintain hemostasis through breakdown
TEG parts R time K time alpha angle MA lysis at 30 min
- R time (5-10 minutes) time to start forming clot. problem with coagulation factors. tx with FFP
- K time (1-3 minutes) time until clot reaches a fixed strength. problem with fibrinogen. tx with cryo
- alpha angle (53-72 degrees) speed of fibrin accumulation. problem with fibrinogen. tx with cryo
- MA (50-70mm) highest verticle amplitude of TEG. platelets
- lysis at 30 min (0-8%) if higher-problem with fibrinolysis. tx with TXA
