9. Blood Pressure Monitoring Flashcards

1
Q

hypotension problems

A

causes decreased tissue organ perfusion
- stroke, MI, renal failure
postoperative delerium

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2
Q

causes of hypotension (8)

A

vasodilation
- anesthetic induced
hypovolemia
pt positioning
- head up (reverse trend, beach chair)
vagal response
chronic steroid pts
decreased cardiac contractility/EF
- decr CO
too large BP cuff
lateral decubitus

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3
Q

hypovolemia causes

A

dehydration/NPO status
blood loss
bowel prep
(reqs 1000-1200mL to replace fluid loss)

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4
Q

hypotension treatments (6)

A

IV fluids and/or blood products
- volume replacement takes time
vasoconstrictors
- treats anesthetic induced vasodilation
lighten anesthetic
change pts position
- trendelenberg
ionotropes
- improve contractility
stress dose steroids

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5
Q

most common cause of hypotension during surgery

A

anesthetic induced hypotension

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6
Q

is there any reason to believe low BP isn’t just vasodilation from the anesthetic?

A

reverse trendelenburg?
high blood loss?
too large BP cuff?
lateral decibutus position?
poor EF?
vagal response after incision?

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7
Q

vasoconstrictors primarily act on

A

peripheral arterioles

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8
Q

vasoconstrictors mechanism

A

decr blood flow in peripherals
incr blood flood to vital organs

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9
Q

hypertension problems

A

LV pumps against greater resistance

incr strain on heart = more O2 consumption

incr strain on cerebral vasculature
–intracerebral hemorrhage and stroke

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10
Q

hypertension etiologies

A

chronic:
- aging
- poor lifestyle (diet, sedentaty, etc)
Acute:
- pain
- light anesthesia

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11
Q

hypertension treatments

A

increase depth of anesthesia
narcotics (works if pt is in pain)
vasodilators

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12
Q

blood flow/perfusion and blood pressure

A

blood flow is proportional to blood pressure

incr BP: incr perfusion
decr BP: decr perfusion

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13
Q

autoregulation of blood flow

A

ability for an organ to maintain constant blood flow over a wide range of blood pressures
brain
heart
kidneys

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14
Q

cerebral autoregulation range

A

MAP: 60-160mmHg

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15
Q

renal autoregulation range

A

MAP: 80-180mmHg

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16
Q

coronary autoregulation range

A

MAP: 50-120 mmHg

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17
Q

if pt is hypotensive, cerebral blood vessels will

A

vasodilate

increases cerebral perfusion

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18
Q

if pt is hypertensive, cerebral blood vessels will

A

vasoconstrict

prevents too much blood flow going to the brain
prevents increase in ICP

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19
Q

cerebral autoregulation curve: Right Shift

A

chronically hypertensive pts
takes higher than normal BP to keep blood flow to the brain constant
lower autoreg level is higher than normal

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20
Q

renal glomerular filtration rate ceases below what level

A

MAP 40-50mmHg

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21
Q

what threshold should we keep pt’s BP within during surgery?

A

20-30% of baseline (preop) MAP value

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22
Q

systolic BP during anesthesia

A

> 90mmHg

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23
Q

diastolic BP during anesthesia

A

> 50mmHg

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24
Q

MAP during anesthesia

A

> 65mmHg

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25
Q

pulse pressure during anesthesia

A

> 35mmHg

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26
Q

“controlled hypotension”

A

surgeon request
decreases bleeding at surgical site

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27
Q

caution during “controlled hypotension” requests

A

sick/chronically hypertensive pts
beach chair position

communicate concerns w/surgeon

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28
Q

If BP falls below autoregulatory range

A

autoregulation organs receive blood flow, just not as much

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29
Q

If BP rises above autoreg range

A

autoreg organs receive more blood flow than they should
BF is proportional to blood pressure

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30
Q

autoregulation ability impairement

A

ischemia
hypercarbia
acidosis
stroke
high end tidal concentration of volatile agent
(>2 MAC)

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31
Q

auscultation is aka

A

sphygmomanometry

32
Q

korotkoff sounds disappear (first time)

A

when artery is completely compressed
no blood flow through compressed artery

33
Q

korotkoff sounds appear

A

when artery is partially compressed
blood flow is turbulent in partial compress state

34
Q

korotkoff sounds disappear (2nd time)

A

when artery is completely open
blood flow is laminar

35
Q

systolic BP manual measurement

A

appearance of korotkoff sound

36
Q

diastolic BP manual measurement

A

disappearance of korotkoff sound

37
Q

NIBP cuff uses

A

oscillometry

38
Q

oscillometry

A

arterial pulses cause oscillations of varying amplitudes in the cuff as it is inflated and deflated

39
Q

BP cuff above systolic

A

pulse amplitude is low
cannot be felt

40
Q

BP cuff at systolic

A

pulse amplitude increases
can be felt

41
Q

BP cuff at mean arterial pressure

A

pulse amplitude at maximum
pulse maximally felt

42
Q

BP cuff at diastolic pressure (and below)

A

pulse amplitude decreases
cannot be felt

43
Q

NIBP cuff determines

A

systolic
diastolic
MAP

separate readings

44
Q

oscillometry is accurate w/

A

regular rhythms

45
Q

oscillometry is inaccurate w/

A

irregular rhythms

46
Q

NIBP cuff sizing: width

A

20-50% greater than extremity diameter

47
Q

BP cuff too large

A

underestimates BP

has to squeeze harder to flatten artery

48
Q

BP cuff too small or loosely placed

A

overestimation of BP

has to inflate to higher pressure to compress artery

49
Q

systolic leg BP

A

10-20mmHg greater than arm BP

50
Q

diastolic leg BP

A

equal (or lower) to BP in arm

51
Q

MAP in leg

A

higher in leg than arm

52
Q

NIBP cuff accuracy

A

only accurate with adequate distal perfusion

53
Q

causes of innacurate BP readings

A

kinked blood pressure tubing
leaning on cuff
defective cuff/cable
limited blood flow to extremity

54
Q

diagnose false BP readings

A

move monitoring site

55
Q

signs low BP is more likely

A

low EtCO2
lack of SpO2 waveform
clinical causes of hypotension
- induction
- large blood loss

56
Q

when to be suspicious of false High BP reading

A

really high diastolic
very narrow pulse pressure

57
Q

NIBP cuff should not be placed

A

on operative arm
side of mastectomy or lymph node removal
- lymphedema risk
arm w/AV fistular or AV graft

58
Q

dialysis

A

excess waster and fluid removed from blood in pts w/renal failure

59
Q

2 types of dialysis

A

hemodyalysis (HD)
peritoneal dialysis (PD)

60
Q

hemodialysis (HD)

A

vein/artery access (fistula, graft, central line)
machine draws blood
machine purified blood
machine returns blood to vein

61
Q

AV fistula

A

artificial connection between artery and vein
larger vain so pt can tolerate dialysis
vein swells bc under higher (arterial) pressure

MAC anesthesia for surgery

62
Q

AV graft

A

artificial tube that connects artery to vein
mature faster than fistulas
higher infection rate/clot risk

63
Q

central line dialysis

A

subclavian vein access
short term solution
12 or 14F

64
Q

peritoneal dialysis

A

solution infused into peritoneal cavity
waster products diffuse across peritoneum into solution
solution w/waste is drained

65
Q

renal failure pt management

A

anemic
restrict fluids
- 500mL bag w/microdrip
cautious of serum [K+] increase
- sux contraindicated
- LR not contraindicated

66
Q

higher measuring site BP impact

A

lower BP reading

67
Q

lower measuring site BP impact

A

higher BP reading

68
Q

lateral decibitus BP

A

dependent arm (lower): BP overestimated
independent arm (upper): BP underestimated

69
Q

sitting/reverse trendelenberg BP reading

A

BP in arm will be higher than BP in brain

BP in brain will be lower than the monitor BP reading

70
Q

phlebostatic axis

A

4th intercostal space
along mid axillary line
external location of right atrium

71
Q

only place in a standing pt where blood pressure readings are not affected by gravity

A

phlebostatic axis

72
Q

what valve aligns with the phlebostatic axis?

A

tricuspid

73
Q

where should blood pressure readings be taken

A

at the level of the heart

74
Q

sitting position BP reading

A

BP in brain is lower than BP in cuff

75
Q

brain BP estimation

A

distance from middle of cuff to the external auditory meatus (ear)

every 1 cm above cuff, MAP decreases by 0.77mmHg