16 Critical Care Flashcards
1
Q
What is the normal range for CO?
A
4-8 L/min
2
Q
What is the normal range for Cardiac Index?
A
2.5-4
3
Q
What is the normal range for systemic vascular resistance? and systemic vascular resistance index?
A
800-1400, 1500-2400
4
Q
What is the normal PCWP?
A
11 +- 4
5
Q
What is the normal CVP?
A
7 +- 2
6
Q
What is the normal pulmonary artery pressures?
A
20-30/6-15
7
Q
What is the normal mixed venous oxygen saturation SvO2?
A
75+-5
8
Q
What percentage of CO does the following organs get? kidney, brain, heart
A
25, 15, 5 respectively
9
Q
What is the formula for MAP?
A
CO x SVR
10
Q
What is the formula for ejection fraction?
A
stroke volume/EDV
11
Q
Cardiac output increases with HR up to 120-150 bpm, then starts to go down, why?
A
decreased diastolic filling time
12
Q
Atrial kick accounts for what % of LVEDV?
A
15-30%
13
Q
Automatic increase in contractility secondary to increase in afterload. What is this effect called? What about automatic increase in contractility secondary to increased HR?
A
Anrep effect
Bowditch effect
14
Q
What is the normal O2 delivery-to-consumption ratio? What increases to keep this ratio constant?
A
5:1, CO
15
Q
What is the normal SvO2?
A
75%
16
Q
What measurement can be thrown off by pulmonary htn, aortic regurg, mitral stenosis, mitral regurg, high PEEP, porr LV compliance?
A
Wedge
17
Q
What is the only way to measure pulmonary vascular resistance?
A
swan
18
Q
Which zone of the lung do you place a swan?
A
zone III (lower lung)
19
Q
Hemoptysis after flushing Swan. Name three interventions.
A
increase PEEP to tamponade the pulmonary artery bleed
mainstem intubate the nonaffected side,
try to place a Fogarty down the affected side,
may need thoracotomy and lobectomy
20
Q
Name two relative contraindications to a swan.
A
previous pneumonectomy, LBBB
21
Q
In this pulmonary artery wedge tracing, wedge pressure is measured at end expiration. Which point is for spontaneous breathing pts and which is for pts undergoing positive pressure ventilation?
A
A is for spontaneous, B is for vent
22
Q
What are the two primary determinants of myocardial O2 consumption -> can lead to myocardial ischemia?
A
increased ventricular wall tension and HR
23
Q
Why is LV blood 5 mmHg of PO2 lower than pulmonary capillaries?
A
unsaturated bronchial blood empties into pulmonary veins
24
Q
What is the normal alveolar-arterial gradient in a non ventilated pt?
A
10-15 mmHg
25
Where is blood with the lowest venous saturation located?
coronary venous blood (30%)
26
Cardiovascular collapse; characteristically unresponsive to fluids and pressors.
Acute adrenal insufficiency
27
hyperpigmentation, weakness, weight loss, GI sx, increased K, decreased Na, fever, hypotension.
chronic adrenal insufficiency
28
Steroid potency:
1x - cortisone, hydrocortisone
___ - prednisone, prednisolone, methylprednisolone
___ - dexamethasone
5x
| 30x
29
Neurogenic shock - loss of sympathetic tone. Usually have decreased HR, decreased BP, warm skin. Tx?
give volume 1st, then phenylephrine after resuscitation; give steroids for blunt spinal trauma with deficit
30
What is the initial alteration in hemorrhagic shock?
increased diastolic pressure
31
What is the tx for cardiac tamponade?
fluid resuscitation initially; need pericardial window or pericardiocentesis
32
What is the CO and SVRI in hemorrhagic shock (increased or decreased)? and septic shock?
CO is decreased, SVRI is increased in hemorrhagic shock
CO is increased, SVRI is decreased in septic shock
33
What is the triad of hyperventilation, confusion and respiratory alkalosis?
early sepsis triad
34
What is the insulin and glucose in early vs late gram-negative sepsis?
Early is decreased insulin and increased glucose due to impaired utilization
Late is increased insulin and increased glucose due to insulin resistance
35
When does hyperglycemia occur in sepsis?
just before pt becomes clinically septic
36
What is activated protein C (Xigris) used for and what is the mechanism?
used for sepsis; mechanism is fibrinolysis
37
What stain can be used to find fat in sputum in urine to help dx fat emboli?
sudan red
38
PA systolic pressures >40, decreased PO2 and PCO2, respiratory alkalosis, chest pain, cough, dyspnea, increased HR
PE
39
What is the tx for air emboli?
place pt head down and roll to left to keep air in RV and RA then aspirate air out with central line or PA catheter to RA/RV
40
When is IABP used? what is the contraindication? what does it improve?
cardiogenic shock, aortic regurgitation, improves coronary perfusion
41
Name the receptor:
vascular smooth muscle constriction; gluconeogenesis, glycogenolysis
Alpha 1
42
Name the receptor:
venous smooth muscle constriction
Alpha 2
43
Name the receptor:
mycocardial contraction and rate
Beta 1
44
Name the receptor:
relaxes bronchial smooth muscle, relaxes vascular smooth muscle; increases insulin, glucagon, rennin
Beta 2
45
Name the receptor:
relax renal and splanchnic smooth muscle
dopamine
46
Name the three receptors and associated effects for dopamine at low (0-5 ug/kg/min), medium (6-10), and high (>10) doses.
low - dopamine receptors (renal)
medium - beta-adrenergic (heart contractility)
high - alpha-adrenergic (vasoconstriction and increased BP)
47
What receptors and affects does dobutamine affect at low (5-15 ug/kg/min) and high (>15) doses.
low - beta-1 (increased contractility)
| high - beta 2 (vasodilation, increased HR)
48
Name the drug that is a phosphodiesterase inhibitor (Increases cAMP). Results in increased Ca flux and increased myocardial contractility. Also causes vascular smooth muscle relaxation and vasodilation.
Milrinone
49
What receptor does Phenylephrine affect?
alpha-1, vasoconstriction
50
What receptors does Norepinepherine affect at low and high doses?
Low - beta-1 (increased contractility)
| High - alpha-1 and alpha-2
51
What receptors does Epinephrine affect at low and high doses?
Low - beta 1 and beta 2 (increased contractility and vasodilation). Can decrease BP at low doses.
High - alpha-1 and alpha-2 (vasoconstriction). Increased cardiac ectopic pacer activity and myocardial O2 demand.
52
Name the drug that hits Beta-1 and beta-2 receptors, increasing HR and contractility, vasodilates. Side effects: extremely arrhythmogenic; increased heart metabolic demand (rarely used); may actually decrease BP.
Isoproterenol
53
Name the Vasopressin receptor:
vasoconstriction of vascular smooth muscle
V-1
54
Name the vasopressin receptor:
water reabsorption at collecting ducts
V-2 (intrarenal)
55
Name the vasopressin receptor:
mediate release of factor VIII and vWF
V-2 (extrarenal)
56
What is the concern with Nipride (arterial and venous dilator)?
Cyanide toxicity at doses ?3 ug/kg/min for 72 hrs; check thiocyanate levels and signs of metabolic acidosis
57
How does nitroglycerin decrease myocardial wall tension?
decreasing preload
58
What is the MOA of hydralazine?
alpha blocker
59
What is the formula for compliance? What does high compliance lungs mean?
change in volume/change in pressure.
easy to ventilate
60
Pts with ARDS, fibrotic lung disease, reperfusion injury, pulmonary edema all have reduce what?
pulmonary compliance
61
Which part of the lungs has the highest V/Q ratio? the lowest?
highest in upper, lowest in lower
62
On a ventilator what can be increased to improve oxygenation (alveoli recruitment) -> improves FRC
increased PEEP
63
On a ventilator what 2 things can be increased to decrease CO2?
increased rate or volume
64
Normal weaning parameters:
```
negative inspiratory force (NIF) > ___,
FiO2 ___
PCO2 93%
off pressors,
follows commands,
can protect airway
```
```
negative inspiratory force (NIF) > 20,
FiO2 60
PCO2 93%
off pressors,
follows commands,
can protect airway
```
65
Barotrauma on vent - high risk if plateus >___ and peaks >___ -> consider prophylactic ___
30,50, chest tubes
66
What does pressure support on a vent do?
decreases the work of breathing (inspiratory pressure is held constant until minimum volume is achieved)
67
Excessive PEEP complications include decreased RA filling, decreased CO, decreased renal blood flow and decreased urine output and increased ___
pulmonary vascular resistance
68
What 3 types of pts where high frequency ventilation is used?
kids, tacheoesophageal fistula, bronchopleural fistula
69
Why is inverse ratio ventilation used? (normal 1:2 I:E phase; go to 2:1)
helps reduce barotrauma
70
What is the formula for minute ventilation?
TV x RR
71
What class of lung disease is represented by decreased TLC, decreased RV, decreased FVC, FEV1 can be normal or increased?
restrictive lung disease
72
What class of lung disease is represented by increased total lung capacity, increased residual volume and decreased FEV1?
obstructive lung disease
73
What is the most common cause of ARDS?
sepsis
74
Acute Lung Injury is defined by acute onset, bilateral pulmonary infiltrates, PaO2/FiO2
PaO2/FiO2
75
What two cytokines mediate SIRS?
TNF-alpha and IL-1
76
What are the 4 SIRS criteria?
Temp >38 or 20 or Pco2 < 32
| WBC >12,000 or 90
77
SIRS -> Sepsis -> Septic Shock -> ___
MOD (Progressive but reversible dysfunction of 2 or more organs arising from an acute disruption of normal homeostasis)
78
What is the name of the syndrome of chemical pneumonitis from aspiration of gastric secretions.
Mendelson's
79
Most common cause of fever in the first 48 hours after operation?
atelectasis
80
What effect does the following have on the lungs?
bradykinin, PGEi, prostacyclin (PGI2), nitric oxide
pulmonary vasodilation
81
What effect does the following have on the lungs?
histamine, serotonin, TXA2, epinephrine, norepinephrine, hypoxia, acidosis
pulmonary vasoconstriction
82
What effect does alkalosis have on pulmonary vasculature? and acidosis?
alkalosis - pulmonary vasodilator
acidosis - pulmonary vasoconstrictor
83
What does nitroprusside, nitroglycerine, and nifedipine do to the pulmonary vasculature?
pulmonary shunting
84
What is the most common cause of postoperative renal failure?
hypotension
85
What percentage of nephrons need to be damaged before renal dysfunction occurs?
70%
86
What is the best test for azotemia?
FeNa
87
What are the three steps to treating Oliguria?
1st make sure pt is volume loaded (CVP 11-15 mmHg), 2nd try diuretic trial (Lasix or butanamide)
3rd dialysis if needed
88
Renin is released in response to decreased pressure sensed by ___ in kidney. Also in response to increased Na concentrations sensed by ___
juxtaglomerular apparatus, macula densa
89
What does renin do?
converts angiotensinogen to angiotensin I
90
What converts angiotensin I to angiotensin II?
angiotensin converting enzyme in the lung
91
What structure releases aldosterone in response to angiotensin II?
adrenal cortex
92
What specifically does aldosterone do to the kidney?
Acts on distal convoluted tubule ATPase to increase resorption of water and sodium and secretion of potassium.
93
What does atrial natriuretic peptide do to the kidney? to the blood vessels?
inhibits Na and water resorption at the collecting ducts
vasodilator
94
What specifically does ADH do to the kidney? the blood vessels?
Acts on the collecting ducts for water resorption
vasoconstrictor
95
How do NSAIDs cause renal damage?
Inhibit prostaglandin synthesis, resulting in renal arteriole vasoconstriction
96
How do aminoglycosides cause renal damage?
direct tubular injury and later renal vasoconstriction
97
Myoglobin causes direct renal tubular injury. What is the tx?
alkalinize urine
98
Contrast dyes cause direct tubular injury. What is the tx?
premedicate with N-acetylcysteine and volume
99
The following things preclude what diagnosis?
uremia, temp <70/40, desaturation with apnea test, drugs, metabolic derangements
brain death
100
How long must the following exist to declare brain death:
unresponsive to pain, absent caloric oculovestibular reflexes, absent oculocephalic reflex, positive apnea test, no corneal reflex, no gag reflex, fixed and dilated pupils.
6-12 hours
101
What two testing modalities can be used to prove absence of brain activity?
EEG - electrical silence
| MRA - will show no blood flow to brain
102
Apnea test – disconnected from ventilation; CO2 >___ mm Hg or increase in CO2 by ___ is a positive test for apnea. If arterial pressure drops to
60, 20
103
Can you still have deep tendon reflexes with brain death?
yes
104
What does carbon monoxide do to a pulse oximeter?
Can falsely increase reading
105
What does carbon monoxide do to hemoglobin?
binds hemoglobin directly creating carboxyhemoglobin
106
What is an abnormal carboxyhemoglobin level? and in smokers?
>10%, >20%
107
What is tx for carbon monoxide poisoning?
100% O2 on a ventilator; may need hyperbaric O2 if really high
108
Methemoglobinemia can occur from nitrites such as Hurricaine spray; nitrites bind Hgb. What is the O2 saturation? What is the tx?
85%, methylene blue
109
Critical illness polyneuropathy – motor > sensory neuropathy; occurs with ____; can lead to failure to wean from ventilation
sepsis
110
In endothelial cells, forms toxic oxygen radicals with reperfusion, involved in reperfusion injury. Also involved in the metabolism of purines and breakdown to uric acid
Xanthine oxidase
111
When do seizures occur with ETOH withdrawal?
48 hrs
112
ICU (or hospital) psychosis generally occurs after which postoperative day? What do you need to rule out?
3rd, metabolic and organic causes
