Chapter 16 - Critical Care Flashcards Preview

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Flashcards in Chapter 16 - Critical Care Deck (100)
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1
Q

How do you calculate MAP?

A

CO x SV

2
Q

How do you calculate CI?

A

CO/BSA

3
Q

How do you calculate SVRI?

A

SVR x BSA

4
Q

what percentage of CO does the brain, kidney, heart get?

A

Brain 15%
Kidney 25%
Heart 5%

5
Q

Preload is linearly related to what?

A

end diastolic volume and filling pressure

6
Q

What is afterload?

A

resistance against the ventricle contracting

7
Q

What is stroke volume determined by?

A

LVEDV, contractility and afterload

8
Q

How do you calculate ejection fraction?

A

stroke volume/end diastolic volume

9
Q

What is end systolic volume determined by?

A

contractility and afterload

10
Q

At what heart rated does CO start to decrease?

A

150- decreased diastolic filling time

11
Q

What % of LVEDV does atrial kick account for?

A

15-30%

12
Q

What is the Anrep effect?

A

automatic increase in contractility secondary to increased afterload

13
Q

What is the Bowditch effect?

A

automatic increase in contractility secondary to heart rate increase

14
Q

what is the radial diastolic and systolic pressure in relationship to aortic mean pressures?

A

diastolic slightly lower, systolic slightly higher

15
Q

How do you calculate O2 consumption (VO2)

A

CO x (CaO2 - Cvo2)

16
Q

What is the normal O2 delivery to consumption ratio?

A

5:1

17
Q

Is O2 consumption supply dependent?

A

No, does not change until levels of delivery are very low

18
Q

What causes a right shift in the O2 dissociation curve?

A
increased CO2
increased temperature
Increased ATP production
increased 2,3-DPG production
increased H+ (decreased pH)
19
Q

What is the normal p50 (O2 at which 50% of O2 receptors are saturated)?

A

27mmhg

20
Q

When does SvO2 go up?

A

shunting or decreased extraction

21
Q

When does SvO2 go down?

A

increased extraction, decreased delivery

22
Q

What can make wedge pressures inaccurate?

A
pulmonary htn
aortic regurg
mitral stenosis/regurg
high peep
poor LV compliance
23
Q

Where should a swan-ganz catheter be placed?

A

zone III (lower) lung

24
Q

What do you do with hemoptysis after flushing a swan-ganz catheter?

A

increase PEEP which will tamponade the pulmonary arter bleed, mainstem intubate non-affected side
can try to place fogarty balloon down the affected side- may need thoracotomy and lobectomy

25
Q

What are contraindications to swan?

A

previous pneumonectomy, left bundle branch block

26
Q

What is the only way to measure pulmonary vascular resistance?

A

swan

27
Q

What are the primary determinants of myocardial O2 consumption?

A

ventricular wall tension and HR

28
Q

what has a higher PO2- pulmonary capillaries or LV?

A

pulmonary capillaries- LV gets unsaturated bronchial blood

29
Q

what is the normal aa gradient?

A

10-15mmhg

30
Q

What blood has the lowest venous saturation?

A

coronary venous (30%)

31
Q

What are the signs of acute adrenal insufficiency?

A

cardiovascular collapse

unresponsive to fluids and pressors

32
Q

signs of chronic adrenal insufficiency?

A

hyperpigmentation, weakness, weight loss, GI sx
decreased K
increased Na
fever, hypotension

33
Q

what steroids are at 1x potency of endogenous?

A

cortisone, hydrocortisone

34
Q

What steroids are at 5x potency of endogenous?

A

prednisone
prednisolone
methylprednisolone

35
Q

What steroids are at 30x strength of endogenous steroids?

A

dexamethasone

36
Q

What do you get with neurogenic shock?

A
loss of sympathetic tone
decreased HR
decreased BP
warm skin
tx: volume then phenylephrine
steroids for blunt spinal trauma
37
Q

what is the initial alteration in hemorrhagic shock?

A

increased diastolic pressure

38
Q

what is beck’s triad?

A

hypotension, jugular venous distention, muffled heart sounds

39
Q

what does echo show in tamponade?

A

decreased RA filling pressures

40
Q

What is the early sepsis triad?

A

hyperventilation, confusion, respiratory alkalosis

41
Q

what do you get in early gram negative sepsis?

A

decreased insulin, increased glucose

impaired utilization

42
Q

What do you get in late gram negative sepsis?

A

increased insulin, increased glucose

secondary to insulin resistance

43
Q

what is the MOA of Xigris?

A

fibrinolysis (activated protein C)

44
Q

What are the signs of fat emboli? where do they usually come from?

A
petechia
hypoxia
confusion
sudan red may show fat in sputum and urine
lower extremity fx
45
Q

What will echo show in pulmonary thromboemboli?

A

RV strain

46
Q

When do you suspect PE?

A
PA systolic >40
decreased PO2 and PCO2
respiratory alkalosis
chest pain
cough
dyspnea, increased heart rate
47
Q

Air Emboli- what do you do?

A

place pt. head down and roll to left, aspirate air out with central line or PA catheter to RA/RV

48
Q

When does an intra-aortic balloon pump inflate, deflate?

A

Inflates on T-wave (diastole); deflates on P-wave or start of q wave (systole)

49
Q

What is a contraindication for an IABP?

A

Aortic regurgitation

50
Q

When is an IABP placed?

A

Cardiogenic shock after CABG, MI or in patients with refractory angina. Decreases afterload.
Improves systolic blood pressure which improves coronary perfusion

51
Q

Where are alpha-1 receptors

A

Vascular smooth muscle constriction; gluconeogenesis, glycogenolysis

52
Q

What do alpha-2 receptors do?

A

Venous smooth muscle constriction

53
Q

What do beta-1 receptors do?

A

Increase myocardial contraction and rate

54
Q

What do beta-2 receptors do?

A

Relaxes bronchial smooth muscle, relaxes vascular smooth muscle, increases insulin, glucagon, rennin

55
Q

What do dopamine receptors do?

A

Relax renal and splanchnic smooth muscle

56
Q

What is the rate of low dopamine administration and what does it affect?

A

05 µg per kilogram per minute acts on dopamine receptors -renal

57
Q

What is the medium dose for dopamine drip and what does it affect?

A

6 to 10 µg per kilogram per minute-beta-adrenergic acts on heart contractility

58
Q

What is the dose for high-dose dopamine and what does it affect?

A

Greater than 10 µg per kilogram per minute acts on alpha-adrenergic receptors causes vasoconstriction and increased blood pressure

59
Q

What is the initial drip rates for dobutamine and what does it do?

A

3 µg per kilogram per minute initially. 5 to 10 µg per kilogram per minute causes beta-1 activation increasing contractility. Greater than 15 µg per kilogram per minute causes alpha adrenergic activation -vasodilation and increased heart rate

60
Q

What does milrinone do?

A

Phosphodiesterase inhibitor increases cAMP
Results in increased calcium influx and increased myocardial contractility
Also causes vascular smooth muscle relaxation and vasodilation

61
Q

What does phenylephrine do?

A

Acts on alpha-1 receptors causes vasoconstriction

62
Q

What does norepinephrine do?

A

Low-dose causes beta-1 activation increasing contractility
High-dose causes alpha-1 and alpha-2 activation
Potent splanchnic vasoconstrictor

63
Q

What does epinephrine do?

A

Low-dose causes beta-1 and beta-2 activation causing increased contractility and vasodilation. Can decrease blood pressure at low doses
High-dose causes activation of alpha-1 and alpha-2 causing vasoconstriction. Increased cardiac ectopic pacer activity and myocardial O2 demand

64
Q

What does isoproterenol do?

A

Beta-1 and beta-2 activation, increases heart rate and contractility, vasodilates.
Side effects are extremely arrhythmogenic, increased heart metabolic demand, may actually lower blood pressure

65
Q

What does vasopressin do?

A

V1 receptors cause vasoconstriction of vascular smooth muscle
V2 receptors are intrarenal and cause water reabsorption at collecting ducts
V2 receptors are extrarenal and mediate release of factor VIII and von Willebrand factor

66
Q

What does nipride to do?

A

Arterial and venous dilator. Can cause cyanide toxicity. Check thiocyanate levels

67
Q

What does nitroglycerin do?

A

Predominantly veno dilation, modest effect on coronaries; decreased myocardial wall tension by decreasing preload

68
Q

What does hydralazine do?

A

Alpha blocker

69
Q

How do you measure lung compliance?

A

Change in volume divided by change in pressure.
High compliance means lungs easy to ventilate. Pulmonary compliance decreases in patients with ARDS, fibrotic lung disease, reperfusion injury, pulmonary edema.

70
Q

What does aging do to lungs?

A

Decreases FEV1 and vital capacity, increases functional residual capacity

71
Q

Where is the V/Q ratio highest?

A

Highest in upper lobes, lowest in lower lobes

72
Q

What does increasing peep do?

A

Improves oxygenation through alveoli recruitment. Improves FRC.

73
Q

How do you decrease CO2 on a ventilator?

A

Increase rate or volume

74
Q

What does pressure support do?

A

Decreases the work of breathing

75
Q

Why do you want to keep FI O2 below 60%?

A

Prevent 02 radical toxicity

76
Q

When do you have a risk of barotrauma?

A

Plateaus greater than 30 and peaks greater than 50

77
Q

What are the complications of hi Peep?

A
Decreased right atrial filling
Decreased cardiac output
Decreased renal bloodflow
Decreased urine output
Increased pulmonary vascular resistance
78
Q

When do you use high-frequency ventilation?

A

Kids; tracheoesophageal fistula, bronchopleural fistula

79
Q

What does inverse ratio ventilation do?

A

Helps reduce barotrauma

80
Q

What is total lung capacity?

A

Lung volume after maximal inspiration. TLC equals FVC plus RV

81
Q

What is forced vital capacity

A

Maximal exhalation after maximal inhalation

82
Q

What is residual volume

A

Lung volume after maximal expiration

83
Q

What is tidal volume?

A

Volume of air with normal inspiration and expiration

84
Q

What is functional residual capacity?

A

Long volume after normal exhalation. FRC equals ERV plus RV

Surgery, sepsis, trauma all decrease FTC

85
Q

What is expiratory reserve volume?

A

volume of air that can be forcefully expired after normal expiration

86
Q

What is inspiratory capacity

A

maximum air breathed in from FRC

87
Q

What is FEV1?

A

forced expiratory volume in 1 second after maximal inhalation

88
Q

What is minute ventilation?

A

TV x RR

89
Q

What does restrictive lung disease do to lung function tests?

A

decreased TLC
decreased RV
Decreased FVC
FEV1 can be normal or increased

90
Q

What does obstructive lung disease do to lung function tests?

A

increased TLC
increased RV
decreased FEV1
FVC can be normal or decreased

91
Q

What is dead space?

A

normally to the level of the bronciole (150mL)
increases with drop in cardiac output, PE, pulmonary HTN, ARDS, excessive PEEP
can lead to high CO2 buildup
-area of lung that is ventilated but not perfused

92
Q

What does COPD do to lung function?

A

increases work of breathing because of prolonged expiratory phase
work of breathing normally 2% of total body VO2

93
Q

what is ARDS and what does it do to lungs?

A
mediated by cellular inflammatory process
increased proteinaceous material
increased gradient
increased shunt
most common in sepsis
94
Q

Diagnosis of Acute lung injury?

A

acute onset
bilateral pulmonary infiltrates
paO2/FiO2 = 18 or no clinical evidence of LAH

95
Q

Diagnosis of ARDS

A

acute onset
bilateral pulmonary infiltrates
PaO2/FiO2 <200

96
Q

What is SIRS mediated by? Criteria?

A

TNF alpha and IL-1

temp >38 or 12 or 90

97
Q

Most potent stimulus for SIRS?

A

lipopolysacharide (Lipid A)

98
Q

Diagnosis of Sepsis?

A

SIRS with clinical evidence of infection

sepsis with organ disfunction

99
Q

Septic shock?

A

Sepsis and arterial hypotension despite adequate volume resuscitation

100
Q

Muti organ dysfunction?

A

progressive but reversible dysfunction of 2 or more organs