Basic Hemodynamic Monitoring Flashcards
Hemodynamic monitoring
Measures chamber pressures with the use of special monitoring catheters and equipment
Mean arterial pressure (MAP)
average pressure at which blood moves through the arteries
How well patient is perfusing tissues & organs
NR: 70-100 mm Hg
Minimum of 60 mm Hg
Calculate MAP
SBP + 2(DBP)/3
OR
(SBP-DBP)/3 + DBP
Cardiac output
Cardiac output = (stroke volume)(heart rate)
Average stroke volume
70-80 mL/beat
Average HR
70 BPM
Average cardiac output
3.5-8 L/min
Three factors of stroke volume
Preload
Contractility
Afterload
Range for stroke volume
60-130 mL/beat
Diastole
Relaxation phase; all four chambers relax, allowing ventricles to fill in preparation for contraction
Systole
Contraction phase; atria contract (atrial systole) and then ventricles contract (ventricular systole) which allows ventricles to fill completely before ejection of blood from chambers
Preload
Amount of blood in each ventricle before blood is ejected;
End diastolic volume;
Determined by how much blood is returned to heart
Afterload
Resistance needed to overcome pressure of semilunar valves; inverse relationship with SV
Direct relationship with mean systolic pressure
High Afterload = high BP
Contractility
Squeeze of ventricles to be able to push out blood
Heart muscle not as effective with age
Pulse oxygen saturation (SpO2)
Oxygen saturation detected by the pulse oximeter estimating the percentage of oxygen molecules bound to hemoglobin molecules
Hgb has high affinity for O & carries ~97% of all O2 (4 receptor sites)
PO2
From arterial blood; give indication of how much O2 is dissolved in blood (NR: 80-100)
More accurate than SpO2
SpO2
Pulse ox reading; percentage of oxygenated Hgb in blood
Signs of low O2
Cap refill >2s, cold hands, groggy, low urine output, mottling (late sign, near death)
Stroke Volume
Amount of blood pushed out from ventricles per beat
How does increased stroke volume affect afterload?
Decreased Afterload (not enough to perfuse tissue)
How does decreased stroke volume affect afterload?
Increased afterload (not enough velocity, heart too weak)
What happens with decreased Contractility?
Poor blood flow
CHF
patient drowning in blood
What occurs with decreased preload?
Decreased perfusion, patient coding
What occurs with increased preload?
Increase in BP
Compliance
How stiff, distended heart is (affects Contractility)
Low compliance = decreased heart function
ex. MI, myopathy
What occurs with too much resistance?
Decreased opening of valves (not enough blood ejected)
Hypertension = “body builder”; increased resistance Hypotension = “baby”; decreased resistance
What is NR for cardiac output? Average?
3500 - 8000 mL/min
Average = 5500 mL/min
What occurs if MAP remains elevated?
Heart will enlarge & grow thicker
Heart becomes weak & can lead to shorter lifespan
Atheroma
Fatty deposits build up on inside of arteries increasing risk of blood clots, MI, stroke
Other hemodynamic assess.
Capillary refill
Urine output (volume to heart is concern)
Skin temp. (Decreased temp. = decreased circulation, volume issue)
LOC
Modeling
Blue tinge to skin, close to end of life
