Lec 5 - Blood Pressure Monitoring

What are the three measurements of arterial BP?

Systolic arterial pressure (SAP), Diastolic arterial pressure (DAP), and Mean arterial pressure (MAP)

What is systolic arterial pressure (SAP)?

Pressure against the arteries generated when the left ventricle is fully contracted

What is diastolic arterial pressure (DAP)?

Minimum pressure maintained between contractions

When is diastolic arterial pressure (DAP) measured?

When the left ventricle relaxes

What is mean arterial pressure (MAP)?

Overall pressure throughout the cardiac cycle

Overall valve between the SAP & DAP, it is closer to DAP dub part that is y it’s a lil longer than Systolic

What is the formula for mean arterial pressure (MAP)?

MAP=(SAP-DAP)/3+DAP

Of the three arterial BP measurements, which is most important when considering perfusion pressure?

MAP (Mean arterial pressure)

Which two values are needed to calculate BP?

CO (Cardiac output) x SVR (Systemic vascular resistance)

Which two values are needed to calculate CO (Cardiac output)?

Heart rate x Stroke volume

Is the vol of blood every time the heart contracts and ejects

How would you define CO (Cardiac output)?

How much blood the heart pumps out per unit time

How would you define stroke volume?

Amount of blood pumped out per heartbeat

What are the two mechanisms that control the response to changes in BP?

Short-duration - mediated through changes in HR and SVR

Long-duration system- acts primary via changes in blood vol and increases SV

Which two primary factors are adjusted in the short-term regulation of blood pressure?

Heart Rate and Systemic Vascular Resistance (SVR)

Which two primary factors contribute to the long-duration response for blood pressure regulation?

Changes in blood volume and Increased stroke volume

What physiological responses would be seen in response to high BP from the rapid-responding short-duration system?

Vasodilation, bradycardia, decreased stroke volume, and decreased contractility

Which hormonal complex is involved in the long-duration blood pressure response system?

RAAS (Renin-Angiotensis-Aldosterone System)

What physiological responses would be seen as a result of the long-duration blood pressure response system?

Profound vasoconstriction, Water and sodium retention, Increased thirst = Expansion of blood volume

what do the Angiotensisn 1 & Angiotensisn 2 do?

Angiotensin 1

• Very potent vasoconstrictor helps w increasing BP

 

Angiotensin 2

•  once activated, releases Aldosterone (hormone) - cause things that will help BP. Ex. Increase Water retention = increases thirst

• Retention of sodium do not want it to escape the body

• Sodium follows water = more sodium = more water in the body

What are some indications for getting a BP measurement?

- All hospitalized Pt

- Geriatric Pt

- Pt getting cardiac meds

- ICU Pt

- Peri- and Post-op monitoring

- Trauma

- Renal failure

- Hyper/Hypotension

How can a direct BP measurement be taken?

Arterial catheterization

Which veins can be used to do an arterial catheterization?

Dorsopedal or femoral

What are the two most popular systems for indirect BP measurement?

Doppler Sphygmomanometric method or Oscillometric system (BP Cuff)

How does the Doppler system work?

Piezoelectric crystals are placed over a peripheral artery to determine flow throughout that artery

the Doppler system can measure what?

systolic pressure

True or False: You do NOT need to shave the area to use a Doppler system.

False

When using a Doppler system, is the BP cuff placed proximal or distal to the Doppler probe?

Proximal

What are some reasons the Doppler system may not be relaying audible signals from an artery?

Insufficient coupling gel, Hair interference, Crystal placement, Hypothermia, or Vasoconstriction

What are some sites where BP cuffs can be placed?

Forelimbs or hindlimbs (proximal to carpus/tarsus), or tail

True or False: When using a BP cuff, the cuff should be raised higher than the heart for an accurate reading.

False - it should be level with the heart

What kind of reading can you get when the BP cuff is too wide?

Falsely low BP

What kind of reading can you get when the BP cuff is too narrow?

Falsely high BP

How can you determine the correct BP cuff size for dogs?

40% of limb circumference

How can you determine the correct BP cuff size for cats?

30% of limb circumference

BP ranges in dogs

SAP 90 -140mmHg

DAP 50 -80mmHg

MAP 60-100mmHg

BP ranges in Cats

SAP 80-140 mmHg

DAP 55-75 mmHg

MAP 60-100 mmHg