Wk Two - Perfusion & Blood Pressure & Homeostasis & VSS

Adequate Perfusion

WPD, 60-100bpm, >100mmHg systolic, Alert & Orientatetd

Borderline Perfusion

CPC, 50-100bpm, 80-100mmHg systolic, Alert & Orientatetd

Inadequate Perfusion

CPC, <50, >100bpm, 60-80mmHg systolic, Alert & Orientatetd OR ALTERED

Extremely Poor Perfusion

CPC, <50, >110bpm, <60mmHg systolic,Altered or Unconscious

No Perfusion

CPC, No pulse, ,No BP, Unconscious

Perfusion definition

Perfusion is the passage of fluid through the circulatory system to an organ or a tissue.

Function of perfusion

Provide tissues with an adequate oxygenated blood supply to meet their functional demands at that time and to effectively remove the associated metabolic waste products.

All the components for maintaining perfusion

• Heart: Pumping Force

• Arteries: Distribution (high pressure)

• Arterioles: Flow and Pressure Regulation (control conduits)

• Capillaries: Exchange fluid, nutrients, electrolytes, hormones, and other substances between the blood and the interstitial fluid

• Venules: Collection

• Veins: conduit of transport back to the heart and blood reservoir

Pressure equation

Pressure = Force/Area

Blood Pressure Def.

the pressure the circulating blood is exerting on the blood vessel walls

What artery is typically used to measure BP?

Brachial A

Mean Arterial Presure Equations

MAP = Diasoltic BP + (1/3 x Pulse Pressure)

OR

MAP = HR x SV x R

Pulse pressure equation

Systolic BP - Diastolic BP

Flow Equation

Change in Pressure/Resistance

Fancy flow equation

Q (Flow) = MAP/Resistance

What is ‘flow’ also known as?

Cardiac Output

Cardiac Output EquationS

CO = HR x SV

OR

CO = MAP/R

What is resistance & what is it effected by?

total peripheral resistance (TPR) - how much opposition to flow there is. It is affected by length, viscosity and radius.

How does length affect resistance?

Double the length - double the resistance. Linear, cannot be changed.

Viscosity def.

measure of a fluids resistance to flow.

How can we change vessel radius to increase blood flow?

Vasodialtors

What relationship does radius have to blood flow?

Parabolic

Stroke Volume Definition

The amount of blood pumped by the left ventricle of the heart in one contraction, measured in mls/beat

Stroke Volume Equation

SV = EDV - ESV

End diastolic volume def.

how much blood is in the ventricle at end of diastole (ie when fullest) = Preload

End systolic volume def. & what it relies on

how much blood in the ventricle at end of systole (ie when emptiest). relies on contractility and afterload

Afterload def.

the pressure the heart needs to work against in order to eject blood during systole

What is Homeostasis

describes any self-regulating process by which biological systems tend to maintain stability. Homeo = similar to, Stasis = standing still.

Hypotension/Hypoperfusion

Low blood pressure, the force of the blood pushing against the arterial ealls is too low. Slower blood flow, can decrease the delivery of O2 and nutrients to vital organs.

Normotension

the state of having normal blood pressure, characterized by values within the healthy range

Hypertension

when the pressure in your blood vessels is too high

BP equation (again?)

BP = HR x (EDV - ESV) x TPR

Neurohormonal factors

Substances that mediate the transmission of nerve impulses or influence physiological processes. (baroreceptors & chemoreceptors)

What affects SVR, HR, Intropy, Venous Compliance & Renal Na and H2O

Feedback Loop

A feedback loop is a biological occurence where in the outpit of a system amplifies the system (positive) or inhibits the system (negative).

Hypovolemia Loop

What is a baroreceptor?

They sense arterial stretch. Most important ones are in the cartoid sinus in the aortic arch.

Cartoid Sinus Massage

A procedure that stimulates baroreceptors in the carotid sinus to help lower heart rate and blood pressure. Gentle pressure to the cartoid sinus in circles.

Renin-Angiotensin-ALdosterone System

Adrenaline Presentation

1mg in 1mL or 1mg in 10mL

What does adrenaline do?

• Increases HR by increasing SA node firing

• Increases conduction velocity through the AV node

• Increases myocardial contractility

• Increases the irratablility of the ventricles

• Causes bronchodialation

• Causes peripheral vasoconstriction

Adrenaline indications, pres, & contras

(Cardiac Arrest, Shock, Bradycardia w poor perfusion, Anaphalaxis, Severe Asthma, and Croup)

CONTRAED IN HYPOVOLEMIC SHOCK WITH NO FLUID REPLACEMENT

Precs = Elderly/frail, patients with cardiovascular disease or with monoamine oxidase inhibitors, and patients on beta blockers.

Adrenaline Side Effects & onset/peaks

(Sinus Tachy, Supraventricular arrhythmias, Ventricular arrhythmias, hypertension, pupilliary dialation, may increase MI, anxiety/palpitations)

GTN Sheet

Saline Sheet

GTN onset & presentation