A 25 year old woman is recovering from severe pneumonia and has been receiving ventilator support for 2 days. Current FiO2 is 0.6, and the PaO2 on this setting is 200 mm Hg. What change in FiO2 would achieve a target PaO2 of 80 mm Hg?
a. 0.75
b. 0.25
c. 0
B
CPAP can only be used with patients who have which of the following characteristics?
a. high PaCO2 levels
b. can breathe spontaneously
c. are hypovolemic
d. have central sleep apnea
B
Patients with COPD can benefit significantly from PEEP levels higher than 10 cm H2O.
a. true
b. false
B. (because of the blebs, their lungs are more likely to rupture)
A primary goal of PEEP therapy is to improve O2 transport.
a. true
b. false
A.
A PEEP study is being done on a patient. When the PEEP is increased from +10 to +15, cardiac output decreases from 4 lpm to 2 lpm. What would be the next most appropriate step?
a. decrease FiO2
b. increase PEEP to +20
c. decrease PEEP to +10
d. make no ch
C
The following table represents a PEEP study for a patient with ARDS. Which PEEP level represents the optimum one for the patient?
A B C D
PEEP 5 8 12 15
PvO2 35 37 39 34
C(a-v)O2 3.7 3.6 3.8 4.1
CO 7.6 7.5 7.6 6.3
O2 transport 875 865 950 825
C
During mechanical ventilation with SIMV, the PEEP level is set at +10 and PIP is 34. The PEEP is increased to +15 and PIP rises to 40. The rise in PIP indicates which of the following?
a. a normal occurrence when PEEP is
increased
b. a bronchospasm
c. the
A
PEEP therapy is commonly used in which of the following conditions?
I. ARDS
II. ALI
III. pneumonia on the R side
IV. CVA
a. I only
b. I and II
c. III and IV
d. I, II, and IV
B
A 38 year old man with ARDS is being mechanically ventilated. The results of an ABG analysis are pH 7.38, PaCO2 42, PaO2 55. The ventilator settings are FiO2 0.9, f 10, Vt 550, PEEP +5. Based on this information, which of the following is the best to chan
D
Recent research suggests the way to establish an optimum PEEP level in a patient with ARDS is to do which of the following?
a. perform a dynamic PV curve maneuver
b. progressively increase the PEEP until CO decreases
c. perform a recruitment-derecruitment
C
Assessment for optimum PEEP is being determined in a mechanically ventilated patient. PEEP is increased progressively from 5 to 10 to 15. Volume delivery remains constant at 450 ml. PaO2 increases progressively from 55 to 63 to 78. BP remains fairly const
B
Referring to the patient above, which of the following modes of ventilation could he be on?
I. VC/AC
II. PS
III. PC
IV. PRVC
a. I only
b. II and III
c. I and IV
d. I, III, and IV
e. II and IV
a. I only (Technically correct)
c. I and IV (PRVC only works if the increase in PEEP doesn't change compliance)
A 70 kg man with bilateral viral pneumonia is on SIMV. His set Vt is 575 ml; SIMV rate is 12/min with no spontaneous breaths; 40% O2; +5 PEEP; and the following ABG values: pH 7.48, PaCO2 30, PaO2 98. Which of the following is appropriate?
a. increase PEE
D
The first parameter to measure following the administration of PEEP is which of the following?
a. HR
b. BP
c. PAOP
d. PAP
B
A patient on CPAP of +10 has a respiratory rate of 36 with pH 7.23, PaCO2 54, PaO2 75 on an FiO2 of 0.5. The most appropriate action to take is to:
a. increase CPAP to +15
b. increase FiO2
c. begin mechanical ventilation
d. decrease CPAP to +5
C
A patient has a P2O2/FiO2 of 150 and severe sepsis. Compliance is reduced and chest radiograph reveals bilateral infiltrates. Which of the following statements are true about this patient?
I. the patient has ARDS
II. this type of patient will probably hav
D
The purpose of setting an adequate PEEP level in ARDS is to:
a. avoid overdistension of the lung
b. prevent alveolar collapse at end exhalation
c. increase perfusion of the lung
d. improve ventilation
B
A patient with ARDS has an ideal body weight of 53 kg. An acceptable Vt would be:
a. 250 ml
b. 320 ml
c. 530 ml
d. 630 ml
A or B (High or Low ends of recommended range)
During mechanical ventilation of patients with ARDS it is strongly recommended that plateau pressure (Pplat) not exceed what level?
a. 30
b. 40
c. 25
d. 50
A
The inflection point on the deflation curve (deflection point) using the PV loop for a patient with ARDS is 8 cm H2O. At what value would PEEP be set?
a. 6
b. 8
c. 12
d. cannot be determined from this information
C or D (technically the answer is 10, but 12 is the closest so either works.
Which of the following indicates that a patient is ready to be weaned from PEEP/CPAP?
I. PaO2 is 80 mm Hg on 30%
II. the patient is stable and has no active
infections
III. C is 37 ml/cm H2O
IV. PaO2/FiO2 ratio is 300
a. I only
b. I and III
c. II and IV
d
D
Which of the following methods can be used to produce inverse ratio ventilation (IRV) on a conventional volume ventilator?
I. long Ti
II. long Te
III. increase Vt
IV. increase pause time
a. I only
b. II and III
c. I and IV
d. II, III, and IV
C
Hypoxia is defined as:
A reduction in oxygen in the tissues.
Hypoxemia refers to:
A reduction in the partial pressure of oxygen in the blood.
Hypoxemia is present when PaO2 is _______ and SaO2 is _________.
PaO2 <80 mmHg
SaO2 < 95%
What are the four types of hypoxia?
1. Hypoxemic Hypoxia
2. Anemic Hypoxia
3. Circulatory Hypoxia
4. Histotoxic Hypoxia
What causes hypoxemic hypoxia (3)?
1. Lower than normal PaO2
2. Ascent to altitude
3. Hypoventilation
What causes anemic hypoxia (3)?
1. Anemia (lower than normal RBC count)
2. Abnormal hemoglobin
3. Carbon monoxide poisoning
What causes circulatory hypoxia (2)?
1. Reduced cardiac output
2. Decreased tissue perfusion
What causes histotoxic hypoxia (1)?
1. Cyanide poisoning
How is hypoxemic hypoxia treated (2)?
1. When it's caused by ascent to altitude, have the person breath an enriched oxygen mixture.
2. When it's caused by hypoventilation, increasing minute ventilation usually helps.
How is anemic hypoxia treated?
Administration of blood products.
How is circulatory hypoxia treated?
Fluid resuscitation and pharmacologic interventions (to normalize cardiac output; i.e., drugs that decrease vascular resistance or increase ventricular contractility).
How is histotoxic hypoxia treated?
Administering a cyanide antidote (such as hydroxocobalamin) and providing supportive care to maintain oxygenation and acid-base balance.
How does cyanide poisoning affect oxygenation?
It interferes with a person's ability to utilize oxygen to produce energy (cellular respiration) by uncoupling oxidative phosphorylation.
A patient with myasthenia gravis is placed on mechanical ventilation. The chest radiograph is normal. Breath sounds are clear. Initial ABG's on 25% FiO2 20 minutes after beginning ventilation are as follows: pH = 7.31; PaCO2 = 62 mmHg; bicarbonate = 31 mE
Tidal volume and respiratory rate will help with the low PH and high CO2. PEEP and F.I.O2 will help with the low oxygen levels.
What are the most common parameters used to assess the oxygenation status of patients (12)?
1. FiO2
2. PaO2
3. SpO2
4. CvO2
5. SvO2
6. PaO2/PAO2
7. PaO2/FiO2
8. Hgb
9. ABG's
10. Shunts
11. Cardiac Output
12. The presence of abnormal Hgb species
DO2 (Oxygen Delivery) provides information about:
Oxygen availability to the tissues.
Oxygen utilized by the tissues can be determined by measuring (4):
1. C(a-v)O2
2. VO2
3. Cardiac Output
4. SvO2
How soon should ABG's be measured in patients when changes are made to FiO2?
Within 15 minutes (though some clinicians choose to wait until after 30 minutes)
What is the formula for calculating desired FiO2?
FiO2(d) = [FiO2(k) x PaO2(d)]/PaO2(k)
What percentage of FiO2 should you aim to use on patients if possible? Why?
FiO2 <0.60 or 60%; This is to avoid complications associated with oxygen toxicity.
What level of PaO2 and CaO2 do you want to maintain while keeping FiO2 below 60%?
PaO2 between 60 and 90 mmHg.
CaO2 as close to normal (20 mL/dL) as possible.
Aside from tissue damage, breathing 100% oxygen for too long can lead to:
Absorption atelectasis and increased intrapulmonary shunting.
What target PaO2 and SpO2 are acceptable lower limits for most adult patients?
PaO2: 60 mmHg
SpO2: 90%
How does PAW affect PaO2
When PAW increases, PaO2 increases as well
What is PAW?
The average pressure above baseline during a total respiratory cycle.
What is the formula for PAW?
0.5[PIPx(I-time/TCT) or 0.5[(PIP-PEEP) x (I-time/TCT) + PEEP]
Factors that affect PAW during positive pressure ventilation (5):
1. PIP
2. Total PEEP (autopeep plus set peep)
3. I:E Ratio
4. RR
5. Inspiratory Flow Pattern
Why is PAW important in the oxygenation of ARDS patients?
Because PAW directly affects mean alveolar pressure (Palv) and alveolar recruitment, and therefore, oxygenation.
What is usually used to increase PAW?
PEEP
Which two types of ventilation can be used to increase PAW?
1. High Frequency Oscillatory Ventilation
2. Airway Pressure Release Ventilation
What other method to increase PAW is not routinely used anymore?
Inverse Ratio Ventilation
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