hemodynamics Flashcards
AANA Standard 9: monitoring and alarms
- monitoring device pitch and threshold alarms on and audible
- BP, HR, RR q 5 min
- continuously monitor
1. oxygenation (pulse ox)
2. ventilation (end tidal)3
3. CV; HR, BP, circulation (EKG)
4. thermoregulation (temp)
5. neuromuscular when applicable
precordial/ esophageal stethoscope
- continuous assessment of heart and breath sounds
- more commonly used in cases with high risk of air embolism
Electrocardiogram (ECG)
- detects arrhythmias
- monitor HR
- detects ischemia
- detects electrolyte changes
- monitor pacemaker function
3 Lead ECG
- electrodes on RA, LA, LL
- not for complex arrhythmia, ST segment elevation or ischemia
5 Lead ECG
- RA, LA, LL, RL, chest
- dysrhythmias/ ischemia seen during anesthesia can be detected by a combination of monitoring leads II and V5.
ST depression
ischemic changes
ST elevation
full thickness ischemia or infarct
ECG for Ischemic Detection
- ST segment change
depression (flat or downslope)elevation >1mm - peaked, flattened or inverted T wave
- Development of Q waves
- Arrhythmias
ST segment
- myocardial repolarization
- ST elevation: ischemia likely r/t acute coronary artery occlusion
- ST depression: ischemia
- CAD pts might have baseline ST segment. abnormalities
- set alarms 1 mm above and below the baseline ST-segment level in patients at high risk for ischemia.
ST segment changes unrelated to ischemia
- drugs (digitalis)
- temp change
- position change
- hyperventilation
Hides ST segment changes
- hypokalemia
- digitalis
- LBBB
- Wolf-parkinson white syndrome
- acute pericarditis
- LVH with strain
QT interval
- highly HR dependent
- if prolonged can be associated with ventricular arrhythmias
R sided leads
- aVR
- V1
L sided leads
- I
- aVl
- V5
- V6
QRS complex
- Left ventricular activity
- normal QRS complex less than 120msec
Systolic BP
ventricular contraction
-changes in SBP correlate with changes in myocardial 02 requirement
Diastolic
ventricular relaxation
-changes in DBP reflect coronary percussion pressure
Ohms Law
BP = CO x SVR
intra op hypotension
MAP between 55-60 mmHG
percussion pressure
systemic = MAP-CVP
pulmonary circulation = Mean pulmonary artery pressure - L atrial pressure (pulmonary artery wedge pressure; PAWP)
noninvasive BP
- palpation: only measures systolic and its underestimated (palpate return of arterial pulse)
- doppler: only reliably measures SBP (sound waves that reflect RBCs moving through artery)
- auscultation: permits estimation of SBP and DBP, BP cuff unreliable in HPTN pts- usually lower (korotkoff sound from blood flow through artery and cuff)
- oscillometry: senses fluctuation/ oscillations in cuff pressure produced by arterial pulsations while cuff deflates (1st oscillation SBP, oscillations end DBP)
Cuff size
Width: 40% of arms circumference
Length: encircle 80% of extremity
- *too large: false low BP
- *too small: false high BP
False High BP
- cuff to small
- cuff too loose
- extremity below heart level
- arterial stiffness (HTN, PVD)
False Low BP
- cuff too big
- extremity above heart
- poor tissue perfusion
- too quick deflation
complications of NIBP
- pain
- petechiae/ ecchymoses
- limb edema
- venous stasis
- thrombophlebitis
- peripheral neuropathy
- compartment syndrome
indications for an A-line
- risk of rapid changes in BP
- deliberate hypotension
- wide swing in intra op BP
- rapid fluid shifts
- repeated blood sampling
- failure of indirect arterial blood pressure measurement
- titration of vasoactive drugs
- End organ disease
A-line
waveform: ejection of blood from the left ventricle to the aorta during systole; peripheral runoff during diastole
A-line sites
avoid extreme wrist dorsiflexion to prevent injury to the median nerve
- radial: most common
- brachial
- ulnar
- axillary
- femoral
less common: dorsalis pedis, posterior tibial, superficial temporal arteries
- axillary and femoral closest to aortic pressure
- peripheral artery waveforms have higher systolic and lower diastolic = wider pulse pressure
RADIAL
A- line complications
overall risk is low.. increased complication if pre-existing
- vasospastic arterial disease
- previous arterial injury
- thrombocytosis,
- protracted shock
- high-dose vasopressor administration
- prolonged cannulation
- infection
Allen Test
- radial and ulnar arteries are compressed
- patient makes a tight fist exsanguinating the palm
-patient then opens the hand (not hyperextending wrist) occlusion of arteries is released
the color of the open palm is observed.
**normal: color returns to palm in seconds
ulnar collateral flow severely reduced if it takes 6-10 seconds
A- line wave form
- area under the curve = MAP
- Peak = systolic pressure
- bottom point = diastolic pressure
phlebostatic axis
- 4th intercostal space alone mid axilla line
- relevant with aline zeroing/ transducing if pt is supine or HOB 60 degree
- if aline not leveled to phlebostatic axis pressures will be false
- high transducer- low BP
- low transducer - hight BP
**20 cm height difference = 15 mmhm difference in BP
Overdampened A-line
OVERLY dampened
- slurred upstroke
- absent dicrotic notch
- loss of fine detail.
** falsely narrowed pulse pressure (MAP still reasonably accurate)
Underdampened A-line
EXAGGERATED
- systolic pressure overshoot –
- may contain elements produced by the measurement system
square wave test
- quick flush of a-line
- waveform rises sharply, plateaus, and drops off sharply
- should only have 2 oscillations after flush
- over-dampened- 1 oscillation
- under-dampened- multiple
Trouble shooting dampened A-line
- Pressure bag inflated to 300 mmHg
- Reposition extremity or patient
- Verify appropriate scale
- Flush or aspirate line
- Check or replace module or cable
overall a-line complications
- Nerve Damage
- Hemorrhage/ Hematoma
- Infection
- Thrombosis 5. Air embolus
- Skin necrosis 7. Loss of digits
- Vasospasm
- Arterial aneurysm
- Retained guide wire
Pulse pressure variation (PPV)
(using aline wave form) difference between maximal (PPMax ) and minimal (PPMin ) pulse pressure values during a single mechanical respiratory cycle, divided by the average of these two values.
Highest BP 150/70 150-70= 80 (max)
Lowest BP 120/60 120-60= 60 (min)
80-60 = 20
20 divided by (80 + 60)/2 = .29 29%
<9% should receive volume >13% should not
Low BP and Sp02 reading
Significantly erroneous reductions in SpO2 readings may be observed for systolic blood pressures lower than 80 mm Hg.
Pulse oximetry
-Beer- Lambert law
Measures transmission of light through a solution to the concentration of the solute in the solution
-measuring hemoglobin oxygen saturation (Sp02)
Pulse ox use
-detect hypoxemia and perfusion
causes of inaccurate pulse ox reading
- venous pulsation/movement
- ambient light - poor perfusion
- additional light absorbers
- malpositon of probe
- dark nail polish
- different hemoglobin (fetal, carboxy, met)
- dyes (methylene blue)
- electrical interference
- shivering
oxyhemoglobin dissociation curve
Sa02 is a function of Pa02 (norm 80-100)
curve flattens out with Pa02 around 70 mmHG and Sa02 between 90-100%
- Pa02 over >70 mmHg has no change on Sa02, can’t tell if you have a large change in Pa02 value
- High Sa02, don’t kn ow exact Pa02 level (normoxic or hyperoxic)
Right shift of oxyhemoglobin dissociation curve
Rids oxygen easily
- acidosis
- hypeRcarbia (increased CO2)
- hypeRthermia ( increased temp)
- increased DPG (rides 02 easier with increased amount)
DPG
2,3-diphosphoglycerate
- made in the red blood cells
- controls the movement of oxygen from red blood cells to body tissues
Left shift of oxyhemoglobin dissociation curve
Latches/ keeps oxygen
- aLkaLosis
- hypocarbia
- hypothermia
- decreased DPG
- carboxyhemoglobin COHb
- fetal Hb
Sp02 accuracy
decreased accuracy at values under 70%
CVC indications
- CVP monitoring
- Pulmonary Artery catheterization and monitoring
- Transverse cardiac pacing
- Temporary hemodialysis
- Drug administration (vasoactive drugs, TPN, chemo, peripheral irritants, prolonged IV abx)
- Rapid infusion via large cannula (trauma, major surgery)
- Aspiration of air emboli
- Inadequate PIV access
- Sampling site for repeated blood testing
CVC insertion sites
**Right IJ (consistent/ predictable; short straight to superior vena cava)
- Left IJ ( >risk
- pneumo
- thoracic duct injury
- increased risk of vascular injury, enter superior vena cava perpendicularly
- subclavian (risk of pneumothorax and arterial puncture)
- external jugular (not common)
- femoral veins (greater risk of infection)
CVC placement
- tip within SVC, just above venae caves and RA
- parallel to vessel walls
- below inferior border of clavicle
- above the level of the 3rd rib, T4/T5 interspace, carina
CVC complications
- Vascular injury
(arterial, venous, cardiac tamponade, chylothorax, hemothorax) - Respiratory compromise
(airway compression from hematoma, pneumothorax) - Nerve injury
- Arrhythmias
- Thromboembolic
(venous thrombosis, pulmonary embolism, arterial thrombosis/ embolism, catheter/ guidewire embolism) - Infection
(insertion site, catheter, bloodstream, endocarditis) - Misinterpretation of data
- Misuse of equipment
CVP monitoring
- cvp pressure = RAP = RV preload
- normal spontaneous breathing person 2-7 mmHg
- Positive Pressure Ventilation increases reading 3-5 mmHg
CVP wave form
‘a’ atrial contraction “atrial kick” (end diastole)
‘c’ isovolumetric right ventricular contraction tricuspid valve closes (early systole)
‘x’ (mid systole) atrium relaxes
‘v’ ventricular ejection, venous filling of atrium (late systole)
‘y’ (early diastole) decreased atrial pressure r/t flow through open tricuspid valve to ventricles
Co-oximetry
blood test that measures the oxygen concentration of all 4 type of hub
**gold standard for Sa02 measurement
4 types of adult Hgb
- oxygenated hemoglobin (02Hb)
- deoxygenated hemoglobin (de02Hb)
- carboxyhemoglobin (COHb)
- methemoglobin (MetHb)
Indications for
Pulmonary Artery Pressure Monitoring
- Surgical cases (cardiac, aortic, OB)
- LV dysfunction
- Valvular disease
- CAD
- Pulmonary HPTN
- Shock/sepsis
- ARF
- ARDS/ resp failure
PA Cath complication
- PA rupture
- Arrhythmia (V-fib, RBBB, complete block)
- catheter knot
- balloon rupture
- air/ thromboebolism
- pneumothorax
- infection
- damage to cardiac structure
Dicrotic notch
ventricle pressure decreases below pressure in pulmonary/ aortic artery and blood flows back toward the heart
PA Cath Right atrium waveform
very similar to cvp wave
‘a’ increased pressure inbound R atrium r/t atrial contraction
‘c’ blood in ventricle, tricuspid valve closes, pressure in ventricle increases
‘x’ atrium relaxes
‘v’ ventricle contracts, ejects blood to semilunar valves, venous filling of atrium
‘y’ ventricle relaxes, decreased pressure, tricuspid valve opens and blood flows from atrium
PA Cath Right Ventricle waveform
waveform uses 1-6
- sharp rise in R. Ventricle pressure related to isovolumetric contraction, pressure continues to increase until it is greater than the PA pressure
- blood is ejected from ventricle to pulmonary artery
- sharp decrease in pressure once blood leaves
- ventricle pressure continues to decrease as the ventricle relaxes and pressure is now < R. atrium pressure
- tricuspid valve opens and blood passively flows from atrium to ventricle
- atrial contraction
PA Cath Pulmonary Artery Pressure
very similar to A-line
happens with T wave
normal PAP 15-30/ 5-15 mmHg
MPAP 9-20 mmHg
pulmonary artery systolic elevation of wave causes by R ventricle contraction and ejection of blood to the pulmonary valve
as the blood is ejected and the pressure in the Right ventricle drops below the pressure in the Pulmonary artery the pulmonary valve closes
This causes a momentary increase in pulmonary artery pressure PAP (DICROTIC NOTCH)
PCWP waveform
same as right atrium wave but waveform less distinct and delayed
supposed to depict L side of heart
‘a’ Left atrial contraction
‘c’ rise in Left ventricle pressure
‘v’ blood enters Left atrium during sytole
more prominent ‘v’ wave is mitral valve insufficiency and blood flowing back into the atrium
