Chapter 1: Principles of Mechanical Ventilation
TRUE/FALSE 1. When a patient fails to ventilate or oxygenate adequately, the problem is caused by pathophysiological factors such as hyperventilation. ANS: F
PTS: 1
REF: Introduction
2. One of the most common causes of increased airway resistance is COPD. ANS: T
PTS: 1
REF: Airway Resistance
3. Airway resistance varies directly with the diameter of the airway or ET tube and inversely with the length. ANS: F
PTS: 1
REF: Airway Resistance
4. Low compliance measurements are usually related to conditions that increase the patient’s functional residual capacity and total lung capacity. ANS: F
PTS: 1
REF: Lung Compliance
5. When looking at the pressure-volume loop, a shift of the slope toward the pressure axis indicates a decrease in compliance. ANS: T
PTS: 1
REF: Lung Compliance
MULTIPLE CHOICE 1. One of the most frequent uses of mechanical ventilation is for the management of postoperative patients recovering from ____. a. apnea and impending respiratory arrest b. anesthesia and medications c. acute severe asthma and heart failure d. acute brain injury and flail chest ANS: B
PTS: 1
REF: Introduction
2. Normal airway resistance in healthy adults is between 0.5 to ____ cm H2O/L/sec. a. 1.5 c. 2.5 b. 2.0 d. 3.0 ANS: C
PTS: 1
REF: Airway Resistance
3. Based on Poiseuille’s Law, the work of breathing increases by factor of ____ when the radius (r) of the airway is reduced by half its original size. a. 8-fold c. 13-fold b. 10-fold d. 16-fold ANS: D
PTS: 1
REF: Airway Resistance
4. ____ occurs when the patient’s minute ventilation cannot keep up with CO2 production.
a. Ventilatory failure b. Refractory hypoxemia ANS: A
PTS: 1
c. Oxygenation failure d. Deadspace ventilation REF: Airway Resistance
5. Which of the following is calculated by C = DV/DP? a. oxygenation failure c. dynamic compliance b. static compliance d. lung compliance ANS: D
PTS: 1
REF: Lung Compliance
6. For critically-ill patients, the dynamic compliance is between 30 and ____ mL/cm H2O. a. 40 c. 60 b. 50 d. 70 ANS: A
PTS: 1
REF: Lung Compliance
7. For critically-ill patients, the static compliance is between 40 and ____ mL/cm H2O. a. 50 c. 70 b. 60 d. 80 ANS: B
PTS: 1
REF: Lung Compliance
8. Which of the following is defined as wasted ventilation, or a condition in which ventilation is in excess of perfusion? a. ventilatory failure c. refractory hypoxemia b. deadspace ventilation d. oxygenation failure ANS: B
PTS: 1
REF: Deadspace Ventilation
9. ____ occurs when the ventilated alveoli are not adequately perfused by pulmonary circulation. a. Alveolar deadspace c. Physiologic deadspace b. Anatomic deadspace d. Arterial deadspace ANS: A
PTS: 1
REF: Deadspace Ventilation
10. Hypercapnia, which involves an increase in ____, is the key feature of ventilatory failure. a. PCO2 c. FIO2 b. PIO2 d. PaCO2 ANS: D
PTS: 1
REF: Ventilatory Failure
11. Which of the following is the difference between tidal volume and deadspace volume? a. minute alveolar ventilation c. (V/Q) ratio b. alveolar volume d. physiologic deadspace ANS: B
PTS: 1
REF: Ventilatory Failure
12. The gas diffusion coefficient for carbon dioxide is ____ times greater than that for oxygen. a. 10 c. 17 b. 14 d. 19 ANS: D
PTS: 1
REF: Ventilatory Failure
13. The classic physiologic shunt equation ____. a. requires only an arterial blood sample b. requires an arterial blood sample and a mixed venous blood sample
c. requires only a venous blood sample d. does not require a blood sample ANS: B
PTS: 1
REF: Ventilatory Failure
14. ____ is reduced oxygen in the body organs and tissues. a. Hypoxemia c. Anemia b. Tachypnea d. Hypoxia ANS: D
PTS: 1
REF: Oxygenation Failure
15. Which of the following is a clinical example of a condition that may lead to ventilatory pump failure? a. emphysema c. pulmonary embolism b. hyperkalemia d. COPD ANS: B PTS: 1 REF: Clinical Conditions Leading To Mechanical Ventilation COMPLETION 1. Regardless of the diagnosis or disease state, patients who require mechanical ventilation generally have developed _______________, oxygenation failure, or both. ANS: ventilatory failure PTS: 1
REF: Introduction
2. In mechanical ventilation, the degree of airway resistance is primarily affected by the length, size, and patency of the airway, endotracheal tube, and _______________. ANS: ventilator circuit PTS: 1
REF: Airway Resistance
3. In a clinical setting, _______________ may result if the patient is unable to overcome the airway resistance by increasing the work of breathing. ANS: hypoventilation PTS: 1
REF: Airway Resistance
4. A(n) _______________ bowing of the P-V loop suggests an overall increase in airflow resistance. ANS: increased PTS: 1
REF: Airway Resistance
5. In a clinical setting, acute respiratory distress syndrome (ARDS) and _______________ are two causes of increased work of breathing. ANS: atelectasis PTS: 1
REF: Lung Compliance
SHORT ANSWER 1. When a patient fails to ventilate or oxygenate adequately the problem may be caused by one of six major pathophysiological factors. List these factors. ANS: 1. increased airway resistance 2. changes in lung compliance 3. hypoventilation 4. V/Q mismatch 5. intrapulmonary shunting 6. diffusion defect PTS: 1
REF: Introduction
2. Outline the method used to measure static and dynamic compliance. ANS: (1) Obtain corrected expired tidal volume. (2) Obtain plateau pressure by applying inspiratory hold or occluding the exhalation port at end-inspiration. (3) Obtain peak inspiratory pressure. (4) Obtain positive end-expiratory pressure (PEEP) level, if any. PTS: 1
REF: Lung Compliance
3. Assessment of compliance can be divided into static compliance and dynamic compliance measurements. Explain the relationship and clinical significance of these measurements. ANS: Static compliance is calculated by dividing the volume by the pressure (i.e., plateau pressure) measured when the flow is momentarily stopped . When airflow is absent, airway resistance becomes a non-factor. static compliance reflects the elastic resistance of the lung and chest wall. Dynamic compliance is calculated by dividing the volume by the pressure (i.e. peak inspiratory pressure) measured when airflow is present Since airflow is present, airway resistance becomes a factor in the measurement of dynamic compliance. Dynamic compliance therefore reflects the condition of airway resistance (nonelastic resistance) as well as the elastic properties of the lung and chest wall (elastic resistance). PTS: 1
REF: Lung Compliance
4. Define deadspace ventilation and describe the three different types of deadspace. ANS:
Deadspace ventilation is defined as wasted ventilation or a condition in which ventilation is in excess of perfusion. The conducting airways contribute to about 30% of deadspace ventilation. For a tidal volume of 500 mL, about 150 mL of this volume is wasted since it does not take part in gas exchange. This volume in the conducting airways is called anatomic deadspace and it can be estimated to be about 1 mL/lb of ideal body weight. Alveolar deadspace occurs when the ventilated alveoli are not adequately perfused by pulmonary circulation. Physiologic deadspace is the sum of anatomic and alveolar deadspace volumes. PTS: 1
REF: Deadspace Ventilation
5. What are the five mechanisms that lead to the development of ventilatory failure? ANS: The five mechanisms are: (1) hypoventilation, (2) persistent ventilation-perfusion (V/Q) mismatch, (3) persistent intrapulmonary shunting, (4) persistent diffusion defect, and (5) persistent reduction of inspired oxygen tension (PIO2) PTS: 1
REF: Ventilatory Failure
Chapter 2: Effects of Positive Pressure Ventilation
TRUE/FALSE 1. During spontaneous ventilation, the diaphragm and other respiratory muscles create gas flow by raising the pleural, alveolar, and airway pressures. ANS: F
PTS: 1
REF: Pulmonary Considerations
2. Positive pressure ventilation causes an increase in intrathoracic pressure and compression of the pulmonary blood vessels leading to an overall decrease in ventricular output, stroke volume, and pressure readings. ANS: T
PTS: 1
REF: Hemodynamic Considerations
3. Oliguria is defined as urine output < 400 mL in 24 hours (or <160 mL in 8 hours). ANS: T
PTS: 1
REF: Renal Considerations
4. The caloric cost of breathing for COPD patients is about 10 times that of normal individuals because of the increased work of breathing necessary to overcome the high airway resistance and V/Q abnormalities. ANS: T
PTS: 1
REF: Nutritional Considerations
5. Sustained hyperventilation of less than 24 hours causes respiratory alkalosis and increases cerebral blood flow and intracranial pressure. ANS: F
PTS: 1
REF: Neurologic Considerations
MULTIPLE CHOICE 1. Under normal conditions, the ____ and tidal volume are directly related in positive pressure ventilation. a. airflow resistance c. alveolar pressure b. pressure gradient d. airway pressure ANS: B
PTS: 1
REF: Pulmonary Considerations
2. Positive pressure ventilation increases ____ and decreases cardiac output. a. PIP c. mPaw b. PEEP d. PI ANS: C
PTS: 1
REF: Cardiovascular Considerations
3. A decreased venous return (or filling of ventricles) leads to a reduction in ____. a. intrathoracic pressure c. compression of pulmonary vessels b. stroke volume d. stroke volume and cardiac output ANS: D
PTS: 1
REF: Cardiovascular Considerations
4. During mechanical ventilation, ____ is not affected to a great extent because of the capability of the systemic venous circulation to compensate or regulate changing blood pressure and volume.
a. pulmonary capillary wedge pressure b. pulmonary artery pressure ANS: A
PTS: 1
c. stroke volume d. cardiac output REF: Hemodynamic Considerations
5. Which of the following is important for eliminating wastes, clearance of certain drugs, and regulating fluid, electrolyte, and acid-base balance? a. intestine c. kidneys b. lungs d. liver ANS: C
PTS: 1
REF: Renal Considerations
6. Which of the following is a drug that is eliminated by tubular secretion? a. digoxin c. furosemide b. vancomycin d. phenobarbital ANS: C
PTS: 1
REF: Renal Considerations
7. ____ dysfunction may be monitored by measuring the prothrombin time and bilirubin and albumin levels. a. Liver c. Cardiovascular b. Kidney d. Gastrointestinal ANS: A
PTS: 1
REF: Hepatic Considerations
8. Which of the following is an effect of PEEP and increased intra-abdominal pressure? a. decreased atelectasis b. decreased functional residual capacity c. increased compliance of ventricles d. increased cardiac output ANS: B
PTS: 1
REF: Abdominal Considerations
9. ____ is an example of a nonmechanical cause of muscle fatigue that may lead to ventilatory failure. a. Low chest wall compliance c. Malnutrition b. Low lung compliance d. High airway resistance ANS: C
PTS: 1
REF: Nutritional Considerations
10. Energy requirements for critically ill patients are normally computed by using the Harris-Benedict equation. This equation estimates the resting energy expenditure (REE) based on weight, height, age, and ____. a. additional metabolic needs c. stress factor b. gender d. degree of infection ANS: B
PTS: 1
REF: Nutritional Considerations
11. When TPN is used, it is essential to keep the amount of dextrose, a(n) ____, to a minimum as it can cause lipogenesis and increase O2 consumption and CO2 production. a. carbohydrate c. fat b. amino acid d. electrolyte ANS: A
PTS: 1
REF: Nutritional Considerations
12. Carbon dioxide acts as a vasodilator in ____ blood vessels. a. hepatic c. gastrointestinal
b. renal ANS: D
d. cerebral PTS: 1
REF: Neurologic Considerations
13. Which of the following is a neurologic change associated with hypoxemia? a. increased cerebral blood flow c. decreased mental and motor functions b. increased intracranial pressure d. impaired cerebral metabolism ANS: C
PTS: 1
REF: Neurologic Considerations
14. During positive pressure ventilation, pressures measured in the ____, left atrium, pulmonary artery, and right atrium are slightly higher than those measured during spontaneous ventilation. a. aorta c. pulmonary veins b. superior vena cava d. left ventricle ANS: A
PTS: 1
REF: Cardiovascular Considerations
15. Which of the following is a pathophysiologic change associated with short-term (<24 hours) hyperventilation? a. leftward shift of oxyhemoglobin curve b. reduced O2 release to tissues c. cerebral tissue hypoxia d. decreased cerebral blood flow ANS: D
PTS: 1
REF: Neurologic Considerations
COMPLETION 1. In _______________, the level of positive pressure is dependent on the mechanical tidal volume, as well as the patient’s compliance and airflow resistance. ANS: volume-controlled ventilation volume controlled ventilation PTS: 1
REF: Pulmonary Considerations
2. During pressure-controlled ventilation, the peak inspiratory pressure (PIP) is preset according to the estimated _______________ requirement of a patient. ANS: tidal volume PTS: 1
REF: Pulmonary Considerations
3. Mean airway pressure is a function of _______________, respiratory frequency, peak inspiratory pressure, and positive end-expiratory pressure. ANS: inspiratory time PTS: 1
REF: Cardiovascular Considerations
4. When _______________ is added to mechanical ventilation, the blood flow to the liver is noticeably reduced.