blood pressure monitoring

Question 1

what is blood pressure

Answer 1

the force that the flow of blood puts on the wall of the vessels

Question 2

what is blood pressure measured in?

Answer 2

mmHg

Question 3

when was blood pressure first performed

Answer 3

1733 - horse jugular

Question 4

what are the 3 numbers of arterial BP

Answer 4

top - SAP - Systolic Arterial Pressure
bottom - DAP - Diastolic A. P
overall number - MAP - Mean A. P.

Question 5

what is systolic arterial pressure

Answer 5

pressure against the arteries - generated when the left ventricle is fully contracted

Question 6

what is diastolic arterial pressure

Answer 6

minimum pressure maintained between contractions - pressure measured when the left ventricle relaxes or at rest

Question 7

what is mean arterial pressure

Answer 7

equates to overall pressure throughout the cardiac cycle

Question 8

what is the formula to calculate MAP

Answer 8

= (SAP-DAP)/3 + DAP

Question 9

when considering perfusion pressure on an organ was is more important of the 3 measurements

Answer 9

MAP

Question 10

what is the formula for BP

Answer 10

Cardiac Output (CO) x Systemic Vascular Resistance (how much resistance/elasticity the blood vessels are)(SVR)

Question 11

what is the formula for cardiac output

Answer 11

Heart rate x Stroke Volume (volume in the circulation)

Question 12

what are the 2 mechanisms that control the response to changes in BP

Answer 12

short-duration and long-duration systems

Question 13

what is the short- duration system for blood pressure regulation

Answer 13

Mediated through changes in HR and SVR (regulated blood pressure minute by minute)

Question 14

what is the long duration system for blood pressure regulation

Answer 14

Acts primary via changes in blood volume and ↑ SV

Question 15

where are the main areas to find baroreceptors

Answer 15

o Left Atrium
o Aortic arch
o Carotid sinus

Question 16

what happens in the rapid-responding short duration system

Answer 16

• increase parasympathetic stimulation of the heart
  o Decrease HR
• decrease sympathetic stimulation of the heart
  o Decrease HR and SV
• decrease sympathetic stimulation of the vasomotor center
  o vasodilation of the blood vessels

Question 17

what is the renin-angiotensin-aldosterone system

Answer 17

hormone system that regulates BP and fluid balance

Triggered by baroreceptors and by direct effects of hypotension on the kidneys

Question 18

what can activate the RAAS (renin-angiotensin-aldosterone system)

Answer 18

o Profound vasoconstriction
o Water and sodium retention
o ↑ thirst
o Net result = expansion of blood volume to maintain BP

Question 19

what patients might we do for BP measurement

Answer 19

	All hospitalized patients – baseline data
	Geriatric patients
	Patients receiving cardiac meds
	ICU patients
	Peri and post-op monitoring
	Trauma
	Renal failure
	Hypertension/hypotension

Question 20

what is direct BP measurement

Answer 20

 Arterial catheterization (dorsopedal or femoral artery)
 Connected to a pressure transducer →convert mechanical fluctuations in the fluid into an electrical signal
 Continuous measurement of BP

Question 21

what is indirect BP measurement

Answer 21

 Less expensive, less time consuming and less technically demanding
 Detect blood flow under or past a pressurized cuff
 2 most popular systems:
o Doppler Sphygmomanometric method
o Oscillometric System

Question 22

what is the doppler system

Answer 22

 “Korotkoff” sounds are inaudible in veterinary patients
 Piezoelectric crystal on a peripheral artery to determine flow throughout that artery
 A BP cuff is placed proximal to the probe and connected to a syphgmomanometer
 Inflate cuff until artery is fully occluded → loss of sound
 Reduce cuff pressure slowly until the sound returns → SAP in dogs and ~ MAP in cats

Question 23

why might you not hear anything for the doppler system

Answer 23

	Weakly/absent audible signals:
o	Insufficient coupling gel
o	Hair interference
o	Crystal placement
o	Hypothermia
o	Vasoconstriction
	Inability to determine DAP and MAP(dogs)

Question 24

what is the Oscillometric System

Answer 24

 Detects oscillation produced by changes in artery wall diameter during blood flow
 Inflating the cuff collapses the artery
 As the cuff is deflated, Amplitude of oscillation:
o Increases at SAP
o Reaches a maximum at MAP
o Decreases at DAP

Question 25

where is the site for cuff placements

Answer 25

o Forelimbs and Hindlimbs, proximal to carpus/tarsus

o Tail

Question 26

what happens if the cuff is too big

Answer 26

o False low BP

o Wide cuff spreads pressure over a larger area, delaying return of the distal pulse

Question 27

what happens if the cuff is too small

Answer 27

o Falsely high BP

o Insufficient pressure and allow early return of the pulse

Question 28

what is the correct cuff width for dogs and cats

Answer 28

o 40% of limb circumference for dogs

o 30% of limb circumference for cats

Question 29

what is the BP range for dogs (SAP?DAP?MAP?)

Answer 29

o SAP: 90-140
o DAP: 50-80
o MAP: 60-100

Question 30

what is the BP range for cats (SAP?DAP?MAP?)

Answer 30

o SAP: 80-140
o DAP: 55-75
o MAP: 60-100

Question 31

what is the in general BP range

Answer 31

o SAP of 120
o DAP of 80
o MAP of 90

Question 32

what is the central venous pressure

Answer 32

 Hydrostatic pressure in the intrathoraxic vena cava – approx = right ventricular pressure
 Changes in blood volume → pressure changes in vena cava
 Estimate right ventricular end-diastolic volume capacity
 Estimate the cardiac function

Question 33

what are the indications of central venous pressure

Answer 33

◦ Monitoring fluid therapy for hypovolemic patients

◦ At risk of volume overload

Question 34

if you have a low CVP what does it mean

Answer 34

less than 0 cmH2O

◦ Hypovolemia (↓ SV), vasodilation

Question 35

when do you not want to place a central line in an animal

Answer 35

 Coagulopathies
 Thromboembolic disease - Hyperadrenocorticism (cushing disease – prone to developing micro clots), Immune-mediated disease
 Intracranial disease - Head trauma, Seizures

Question 36

if you have a high CVP what does it mean

Answer 36

(Greater than 10cmH2O)
◦ Volume over load
◦ Right-sided heart failure
◦ Significant pleural effusion,
◦ Pericardial effusion (acculmation of fluid in the pericardial sac)
◦ Cardiac tamponade (a result of pericardial effusion)

Question 37

what is the normal range for central venous pressure

Answer 37

◦ 0-10cmH2O TRENDS