Perfusion Flashcards
Normal Function of the Heart
Rhythmic cycle of contraction and relaxation
Systole
Contraction of the Ventricles:
LV-> Aorta (oxygenated)
RV->Pulmonary artery (unoxgenated)
Diastole
Relaxation of the ventricles
- atria contract
- blood moves into the ventricles
- blood fills coronary arteries
S1
tricuspid and mitral valves close – soft lubb sound – beginning of systole
-best heard with the diaphragm of stethoscope (hi-pitched)
S2
closure of aortic and pulmonic valves – sharp dupp sound – signals beginning of diastole
–best heard with the diaphragm of stethoscope (hi-pitched)
S3 and S4
Extra sounds best heard with bell since they are low pitched.
2 main factors influencing BP
Cardiac output and SVR
BP = CO x SVR
Cardiac Output (CO):
Amount of blood pumped each minute (4-8L/min at rest) stroke volume (SV) x heart rate (HR) = CO
Stroke Volume
the amount of blood pumped by the ventricle with each heartbeat
Pulse pressure
the difference between SBP and DBP. Normally about 1/3 of the SBP. Example – 120/80 PP = 40
MAP (mean arterial pressure)
average pressure within the arterial system felt by the organs in the body
(2XDBP + SBP)/3 = MAP: 60 and above OK
Conduction system is responsible for:
creating and transporting the electrical impulses of action potential. Entire process takes
Impulse Conduction
Sinoatrial Node (SA Node) → Atrioventricular Node (AV Node) → Bundle of His → Purkinje Fibers
Sinoatrial Node (SA Node)
Pacemaker of heart
Located in the wall of right atrium
Purkinje fibers
Bundle branches and purkinje fibers carry the impulse throughout the ventricles, causing them to contract
Characteristics of Normal Perfusion: Adults
– Skin temperature and color: warm skin and deep
pink mucus membranes
– Heart rate: 60-80 beats/min
– Blood pressure: 120/70
– What is mean arterial pressure? (MAP> 60)
– Pulse pressure: difference between SBP/DBP
– Women tend to have slightly lower BP than
men
– African American males have slightly higher BP
– BP varies throughout day, highest in afternoon
– Position change causes only slight variation
– Physical exertion causes minimal change in
diastolic BP, but systolic BP increases
– Older adult: progressive increase in SBP with
decrease or no change in DBP
Lifespan Considerations: Newborn and Infant
Skin temperature and color: cool with acrocyanosis at birth
HR 100-180 beats/min at birth
Then warm skin and deep pink mucus membranes
Heart rate:
100 – 150 beats/min
HR
Lifespan Considerations: Toddler and Preschooler
Pulse: 70 – 110 (80-120 up to 2 yrs)
BP: 90/50
Note any S/S indicative of heart disease:
- Poor weight gain
- Developmental delay
- Tachycardia
- Tachypnea
- CyanosisFactors Affecting Perfusion
- Activity and Exercise
- Obesity
- Ethnicity/Race
- Gender
- Body Position
- Smoking
- Medications
- Caffeine
- Alcohol
- Age
Risk Factors for Cardiovascular disease/Problems of Perfusion
Fixed
Major
Minor
Postural hypotension is
- considered a failure of the cardiovascular system or nervous system to react appropriately to sudden changes.
- Normally, when you stand up, some blood pools in your lower extremities. But your body normally compensates by sending messages to your heart to beat faster and to your blood vessels to constrict. This offsets the drop in blood pressure.
- Uncorrected, this would cause your blood pressure to fall.
- If this compensation does not happen, or happens too slowly, postural hypotension results.
How does Age affect Perfusion
Age
What would vavlular rigidity cause?
Systolic murmur (aortic or mitral)
