Shock & CV Flashcards
SNS reserve
Ability to ramp up activity levels. 5L/min-25L/min. Expressed as percentage above. 400%. 4 fold increase.
Elite athletes: 30-40L/min
High Pulmonary Venous Pressure
Prevents fluid reabsorption at the venular end of the capillary. Fluid in lungs
Severe Myocardial Infarct
- Initially inadequate cardiac output.
- Autonomic compensation
- Volume retention
- Not enough cardiac output to survive challenge.
Heart Failure
- Initially cardiac function inadequate for minimum CO.
- After digitalis, cardiac output above minimum required.
- Allow diuresis and decrease blood volume.
Swan
Gold standard for measuring cardiac output.
Indication dilution test
Faster the dilution the faster the CO
Fick Equation
Measures how much oxygen delivered vs. how much blood required to carry said oxygen.
DL/min(Deciliters/min)
CO(L/min)=O2 absorbed per minute by the lungs(mL/min)/Ateriovenous O2 difference(mL/L of blood)
SVO2
Saturation of Venous Hgb of Oxygen
Arterial Blood
20mL O2/dL
Venous Blood
15mL O2/dL
Normal O2 Absorption(Vo2)
250mL O2/min
Deciliter(DL)
1/10th of a liter
Coronary Circulation Oxygen Concentration
High oxygen extraction rate 20-15=5mL O2/dL
Pulse Pressure Variation
Affected by ventilation, predictor of fluid responsiveness. Can give 100-250mL bolus or passive leg raise.
SBP drop during inspiration
less than10mmHg. If empty, could drop more than 10.
Pulsus Paradoxus
Drop of more than 10mmHg
The more ischemic..
The more permeable
Steroid use in Shock
Help stabilize cell wall and reduce permeability
Shock Treatment
Pressor, Inotrope, steroid, fluids, colloids, positioning, oxygen
Carotid Bifurcation
3 important nerves
Medulla
Lower part of brain stem
CV System Reflexes
Epi/Norepi, SVR, Contractility, HR, Vasopressin, RAAS, ANF/ANP reduction, renal fluid retention, blood shifts(spleen), thirst, CNS ischemic response
CNS Ischemic Response
Strongest CV reflex in the body. Tells all blood vessel to constrict. Can increase BP to over 200 even in low blood volume states. Oscillations
Pcap
30-10mmHg
Pisf
-3mmHg
Conditions with no reserve
- Severe coronary thrombosis
- Severe valvular disease
- Normal reserve
- Athlete Reserve
- Mild valvular disease
- Moderate CAD, Diphtheria
- 400%
- 600%
- 300%
- 150%
Drug reserved for the end of Heart Failure
Digitalis
Parameters used to assess Shock
- CO
- SVR
- CVP
- Blood Gas-PH
- Swan
- Flow track
- Venous Blood gas
- Lactate
- Coags
Retrograde perfusion
Backwards blood flow toward the aortic valve as it closes, this in turn feeds the coronary arteries.
Impedance Changes
More blood flowing, lot of iron in Hgb, this will mess with electromagnetic field
Echocardiogram
Use to estimate Stroke volume then multiply by HR to estimate CO.
Lysosomes
In ischemia, they begin to dissolve parts of the endothelial cells which will create holes. This allows colloids to leave. Lose osmotic pressure. Decrease blood volume.
Medulla
Lower part of Brain stem. Major controller of CV system.
Contractility, SVR, HR
Spleen
Source of Hgb and RBCs
Oscillations
Baroreceptor mediated maintenance of BP.