Acute Respiratory Failure I and II and Chronic Respiratory Failure

Question 1

Hypoexemic Respiratory Failure

Answer 1

– Hypoxemic (“Type 1”)

• PaO2 <60 mmHg

Question 2

Hypercapnic Respiratory Failure

Answer 2

-Hypercapnic (Ventilatory-”Type 2”)

• PaCO2 >50 mmHg

Question 3

Hypoxemic Respiratory Failure Causes

Answer 3

• Pneumonia
• Cardiogenic Pulmonary Edema
• Noncardiogenic Pulmonary Edema

– Acute Respiratory Distress Syndrome (ARDS)

• Others

Question 4

Causes of Hypoxemia

Answer 4

• Ventilation/Perfusion Abnormalities
• Shunt
• Hypoventilation
• Diffusion
• Decreased “FIO2 ” (PIO2)

Question 5

Hypercapnic Respiratory Failure Causes

Answer 5

• CNS depression
• Neuromuscular Disease
• Chest wall abnormalities
• Upper airway obstruction
• Obstructive lung disease

Question 6

Status Asthmaticus

Answer 6

• Inability to speak in phrases or full sentences
• Use of accessory muscles
• Pulsus paradoxus >25 mmHg
• Eucapnia or hypercapnia
• “Quiet” chest
• Altered mental status

Question 7

Answer 7

Variable Extrathoracic Obstruction

Question 8

Answer 8

Variable Intrathoracic Obstruction

Question 9

Causes of Pulmonary Edema

Answer 9

• Increased capillary hydrostatic pressure
• Increased capillary permeability
• Reduced lymph drainage
• Decreased interstitial pressure
• Decreased colloid osmotic pressure
• Uncertain etiology

– High altitude

– Neurogenic

– Heroin

Question 10

Capillary hydrostatic pressure favors movement […] of the capillary.

Answer 10

out

Question 11

Plasma colloid oncotic pressure favors movement […] the capillary.

Answer 11

in to

Question 12

Tissue hydrostatic pressure favors movement […] the capillary.

Answer 12

in to

*except in the lung where tissue hydrostatic pressure is probably negative

Question 13

Tissue colloid pressure favors movement […] the capillary.

Answer 13

out of

Question 14

Clinical Disorders Associated with the Development of ARDS - Direct Lung Injury

Answer 14

Direct Lung Injury

• Common Causes

– Pneumonia

– Aspiration of gastric contents

• Uncommon Causes

– Pulmonary contusion

– Fat emboli

– Near drowning

– Inhalational injury

Question 15

Clinical Disorders Associated with the Development of ARDS - Indirect Lung Injury

Answer 15

Indirect Lung Injury

• Common Causes

– Sepsis

– Severe trauma with shock

• Uncommon

– Acute pancreatitis

– Transfusion of blood products (TRALI)

Question 16

Answer 16

Acute ARDS ( diffuse alveolar damage)

Question 17

Answer 17

ARDS Fibroproliferative Stage

Question 18

Hypercapnia - decreased alveolar ventilation

Answer 18

• increased physiologic dead space
• decreased minute ventilation

Question 19

pulsus paradoxus

Answer 19

Pulsus paradoxus, also paradoxic pulse or paradoxical pulse, is an abnormally large decrease in stroke volume, systolic blood pressure and pulse wave amplitude during inspiration. The normal fall in pressure is less than 10 mmHg. When the drop is more than 10 mmHg, it is referred to as pulsus paradoxus.

Question 20

stridor

Answer 20

• on inspiration
• extrathoracic

Question 21

Respiratory Failure

Answer 21

The term respiratory failure is used clinically to denote failure of the respiratory system to deliver oxygen to the blood and to remove carbon dioxide.

Question 22

Respiratory Failure Diagnosis

Answer 22

• begins wih clo=inical suspicion
• confirmation based on ABG analysis
• cardiogenic
• develops in the context of a history of left ventricular dysfunction or valvular heart disease
• A history of previous cardiac disease, recent symptoms of chest pain, paroxysmal nocturnal dyspnea, and orthopnea suggest cardiogenic pulmonary edema

•noncardiogenic

• ARDS
• typical clinical contexts such as sepsis, trauma, aspiration, pneumonia, pancreatitis, drug toxicity, and multiple transfusions.

Question 23

Cardinal Symptom of Respiratory Failure

Answer 23

dyspnea

Question 24

Physical Exam Findings in Respiratory Failure

Answer 24

The signs and symptoms of acute respiratory failure reflect the underlying disease process and the associated hypoxemia or hypercapnia. Localized pulmonary findings reflecting the acute cause of hypoxemia, such as pneumonia, pulmonary edema, asthma, or COPD, may be readily apparent. In patients with ARDS, the manifestations may be remote from the thorax, such as abdominal pain or long-bone fracture.

Question 25

Lobar Pneumonia Physical Exam Findings

Answer 25

• dullness to percussion
• bronchial breath sounds
• crackles
• egophony.

Question 26

Status Asthmaticus and Severe Hypercapnic Respiratory Failure

Answer 26

• patients will be unable to speak in full sentences and will use accessory muscles due to difficulty breathing
• pulsus paradoxus >25 mmHg is associated with severe status asthmaticus.
• Neurological manifestations include restlessness, anxiety, confusion, seizures, or coma

Question 27

Asterixis

Answer 27

• a tremor of the hand when the wrist is extended, sometimes said to resemble a bird flapping its wings
• this motor disorder is characterized by an inability to maintain a position, which is demonstrated by jerking movements of the outstretched hands when bent upward at the wrist
• observed with severe hypercapnia

Question 28

Myoclonis and Seizures

Answer 28

•may be observed with severe hypoxemia

Question 29

Tachycardia and Various Arrythmias

Answer 29

•may result from hypoxemia and acidosis

Question 30

Cyanosis

Answer 30

• a bluish color of skin and mucous membranes, indicates hypoxemia
• visible cyanosis typically is present when the concentration of deoxygenated hemoglobin in the capillaries or tissues is at least 5 g/dL

Question 31

Polycythemia

Answer 31

• a disease state in which the hematocrit (the volume percentage of red blood cells in the blood) is elevated
• complication of long standing hypoxemia

Question 32

Pulmonary Hypertension - Cor Pulmonale

Answer 32

• frequently is present in chronic respiratory failure
• Alveolar hypoxia potentiated by hypercapnia causes pulmonary arteriolar constriction. If chronic, this is accompanied by hypertrophy and hyperplasia of the affected smooth muscles and narrowing of the pulmonary arterial bed. The increased pulmonary vascular resistance increases afterload of the right ventricle, which may induce right ventricular failure. This, in turn, causes enlargement of the liver and peripheral edema.
• The entire sequence is known as cor pulmonale. The definition of cor pulmonale includes the requirement that the pulmonary hypertension and right ventricular dysfunction must be due to diseases of the lung.
• Right heart disease due to left heart failure or congenital heart disease is NOT considered cor pulmonale

Question 33

Acute Respiratory Distress Syndrome

Answer 33

• an acute, diffuse, inflammatory form of lung injury that is associated with a variety of etiologies.
• Clinically, ARDS is acute respiratory failure characterized by the acute onset of bilateral alveolar opacities and hypoxemia.
• Approximately 10 to 15 percent of patients admitted to intensive care units have ARDS.
• Healthy lungs regulate the movement of fluid to maintain a small amount of interstitial fluid and dry alveoli, as described in the Starling equation. The injury to the lung markedly increases the alveolar capillary permeability causing excess fluid in both the interstitium and alveoli. Consequences include impaired gas exchange, decreased compliance, and increased pulmonary arterial pressure

Question 34

Diagnostic Criteria for ARDS

Answer 34

1. Respiratory symptoms must have begun within one week of a known clinical insult,or the patient must have new or worsening symptoms during the past week.
2. Bilateral opacities must be present on a chest radiograph or computed tomographic (CT) scan.
3. The patient’s respiratory failure must not be explained by cardiac failure or fluid overload.
4. A moderate to severe impairment of oxygenation must be present, as defined by the ratio of arterial oxygen tension to fraction of inspired oxygen (PaO2/FiO2). The severity of the hypoxemia defines the severity of the ARDS