Hemodynamic Monitoring Flashcards
Systole
Contraction
* Ventricles eject blood into the aorta and pulmonary artery
Diastole
Ventricular relaxation and filling
* When blood return blood to the heart in preparation for the next ventricular contraction
Four properties of the myocardial cell
- Automaticity (Chronotropic)
- Conductivity (Dromotropic)
- Contractility (Inotropic)
- Excitability (Bathmotropic)
Chronotropy
- Chrono=time
- The rate of contractions
- Positive chronotropic drugs increase HR
- Negative chronotropic drugs decrease HR
Chronotropic effects of Beta blockers
Negative chronotropic
effects of Calcium channel blockers
Negative chronotropic
Negative inotropic
* Calcium increases the strength of contractions, so by blocking calcium you decrease the strength of those contractions
All beta blockers end in what
lol
All calcium channel blockers end in
Pine/ zem
(Amlodipine/ Cardizem)
Amiodarone chronotropic effects
Negative chronotropic effects
(Also turns you blue)
Inotropes
Affect the contractility of the heart
* Positive increase the contractility, used to pump more blood with fewer heart. beats
* Negative decrease the contractility: and to decrease the HR
Why do we give positive inotropes
- CHF
- Cardiomyopathy
- Recent MI
- Cardiogenic shock
Why do we give negative inotropes
- Weaken the contractions of the heart and slows the HR
- HTN
- Chronic heart failure
- Arrhythmias
- Chest pain
Also used in MI patients to decrease the burden on the heart
Dromotropy
Affects the conduction speed at the AV node, increasing/decreasing rate which electrical impulses move through the heart
* Positive increases conduction velocity
* Negative decreases velocity (Vagal stimulation)
Contractility
Force which the heart is able to contract
* Essential property of all muscles this is what allows the heart to act as a pump
Frank starling laws
Essentially the heart is a rubber band, the more you’re able to stretch the muscle (More full), the more powerful the contraction
* Increasing preload increases contractility
Digoxin, effects on the heart
- Lowers HR (Negative chronotropic effects)
- Increases contractility (Positive inotropic effects)
Cardiac Output (CO)
Amount of blood pumped by the heart in one minute (L/min)
Preload
- Stretch of the ventricle, due to be filled with blood at the end of diastole
- LVEDP
diseases with increased preload
- HF
- Valve diseases
- Increasing O2 demand
Meds that decrease preload
- Ace inhibitor
- Arbs
- Diuretics
- Nitrates
- calcium channel blockers (CCB)
LVEDP
Left ventricle end diastolic pressure
Stretch of the ventricle at the end of diastole, known as preload
Afterload
- The pressure which the heart must work against to be able to eject its blood during systole
- Increased afterload makes the heart work harder decreasing CO
Conditions that increase afterload
Aortic stenosis and elevated BP
Stroke volume
- Volume of blood pumped by LV during one contraction
- Normal is 50-100
Venous return
- Blood needs to come back to the heart in order to pump it
- Volume of blood from the veins that returns to the atria each min
- Venous has a huge impact on cardiac
Systemic vascular resistance
Total peripheral resistance, and the force which is exerted onto the blood by the vasculature of the body
Pulmonary vascular resistance
Resistance against blood flow from the pulmonary artery to left atrium
Cardiac output
SV * HR
Goal of hemodynamic monitoring
* Maintain adequate tissue perfusion
- identify the presence and nature of shock
- Guide response to resuscitation
- Eval volume state
- measure cardiac contractility
- and systemic vascular resistance
You need sufficient CO to keep BP and supply O2 rich blood to the brain and organs