Ch. 11 Flashcards
Define respiratory failure.
the inability of the respiratory system to maintain an adequate amount of (1) oxygen (O2) exchange between the alveoli and the pulmonary capillaries, or (2) carbon dioxide (CO2) removal out of the lungs, or (3) a combination of both.
Identify the six major anatomic alterations of the lungs
and subsequent clinical scenarios that can lead to respiratory failure.
(1) atelectasis
(2) alveolar consolidation
(3) increased alveolar- capillary membrane thickness
(4) bronchospasm
(5) excessive bronchial secretions
(6) distal airway and alveolar weakening
Evaluate the two major classifications of respiratory
failure.
(1) hypoxemic (type I) respiratory failure, or (2) hypercapnic (type II) respiratory failure, or (3) a combination of both.
Describe hypoxemic respiratory failure (type I)
(oxygenation failure).
Hypoxemic respiratory failure (type I) is used to describe a patient whose primary problem is inadequate oxygenation. Patients with hypoxemic respiratory failure typically demon- strate hypoxemia—a low PaO2—and a normal, or low PaCO2 value.
Explain respiratory disorders associated with hypoxemic
respiratory failure.
Discuss the pathophysiologic mechanisms of hypoxemic
respiratory failure.
(1) alveolar hypoventilation,
Oxygenated blood
(2) pulmonary shunting, and
(3) ventilation-perfusion (V /Q ) mismatch.
Describe hypercapnic respiratory failure (type II)
(ventilatory failure).
when the primary problem is alveolar hypoventilation. Patients
with hypercapnic respiratory failure demonstrate an increased
PaCO2 and, without supplemental oxygen, a decreased PaO2.
Describe the pathophysiologic mechanisms of hypercapnic
respiratory failure.
- Alveolar hypoventilation
- Inc. dead space disease
- V/Q ratio mismatch
Explain respiratory disorders associated with hypercapnic
respiratory failure.
Differentiate the types of ventilatory failure.
(1) acute ventilatory failure (high PaCO2 and low pH), or (2) chronic ventilatory failure (high PaCO2 and normal pH).
Describe the major components of the mechanical
ventilation protocol.
Non invasive or invasive ventilation
What is pulmonary shunting?
the portion of the cardiac output that moves from the right side to the left side of the heart without being exposed to alveolar oxygen (PAO2)
What is alveolar hypoventilation?
an abnormal condition of the respiratory system that develops when the volume and distribution of alveolar ventilation is not adequate for the body’s metabolic needs. It is characterized by an increased PaCO2 level and, without supplemental oxygen, a decreased PaO2.
What is V/Q mismatch?
Under normal conditions, the overall alveolar ventilation is
about 4 L/min and pulmonary capillary blood flow is about
5 L/min, making the average overall ratio of ventilation to
blood flow about 4 : 5 or 0.8.
What is the formula for the VD/VT ratio?
What is the formula for the A-a gradient?
PAO2 = FIO2 (PB − PH2O) − PaCO2 x 1.25
What is the normal range for the A-a gradient?
7-15mmHg
What is another name for Hypercapnic Respiratory Failure?
Ventilatory failure
What is another name for Hypoxemic Respiratory Failure?
Oxygenation failure
What are the common causes of alveolar hypoventilation?
central nervous system depressants, head trauma, chronic obstructive pulmonary disease, obesity, sleep apnea, and neuromuscular disorders (e.g., myasthenia gravis or Guillain-Barré syn- drome).
What is the tx for alveolar hypoventilation?
Ventilate support
What are absolute shunts?
(also called true shunt) are commonly classified under two major categories: anatomic shunt and capillary shunt.
What is the normal anatomic shunt?
In the healthy lung, there is a normal anatomic shunt of about 3% of the cardiac output.
What are capillary shunts?
caused by (1) alveolar collapse or atelectasis, (2) alveolar fluid accumulation, or (3) alveolar con- solidation or pneumonia
