10 - resp failure Flashcards Preview

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Flashcards in 10 - resp failure Deck (17)
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1
Q

respiratory failure definition

A

potentially life-threatening deterioration in gas exchange function of resp. system –> impairment of oxygenation, inadequacy of CO2 excretion or a mixture of both

2
Q

oxygen/CO2 cascade

A

ventilation, altitude and FIO2 determine PAO2 (alveolar). V/Q matching and the shunt help determine PaO2 (arteriolar). SaO2 and Hb conc determine CaO2 –> O2 delivery –> tissue oxygenation

3
Q

diagnosis of respiratory failure

A

suspected on basis of history and physical exam: but arterial blood gas required to confirm diagnosis

4
Q

clinical features of resp failure are ____, and are related to ____?

A

nonspecific: often related to underlying cause of failure (and not resp failure itself), or due to end organ dysfunction

5
Q

clinical features of resp. failure

A

dyspnea, fatigue, headache, anxiety, confusion, tachypnea or bradypnea, altered mental status, cyanosis, accessory muscle use, indrawing, paradoxical abdominal breathing

6
Q

normal ABG values

A

PaO2 > 60 mmHg. PaCO2 = 40 mmHg. [H+] 20nM/L –> pH 7.4. [HCO3-] 24 mmol/L

7
Q

classification of respiratory failures

A

type 1 = impaired oxygenation. 2 = hypoventilation. 3 = mixed.

8
Q

what happens to VA, PAO2, PaCO2, PaO2 during hyperventilation

A

increased alveolar ventilation: as a result, alveolar oxygen increases, and so arteriolar oxygen increases too. arteriolar CO2 decreases

9
Q

what happens to VA, PAO2, PaCO2, PaO2 during hypoventilation

A

decreased ventilation: decreased PAO2, PaO2 and increased PaCO2

10
Q

what happens to VA, PAO2, PaCO2, PaO2 oxygen impairment

A

abnormal AaDO2: so decreased PaO2 (also decreased PaCO2). as a result, VA increases, and so does PAO2

11
Q

definition of hypoxemia

A

PaO2 < 60 mmHg and/or SaO2 < 90%

12
Q

mechanisms of hypoxemia: categorized into normal and abnormal lungs

A

normal: decreased FiO2 or barometric pressure, hypoventilation. abnormal: shunt, diffusion impairment, ventilation-perfusion mismatch

13
Q

hypercapnia definition and causes

A

PaCo2 > 40 mmHg with or without acidosis –> caused by increased CO2 production, increased deadspace ventilation, decreased minute ventilation

14
Q

CO2 production is increased by? only leads to hypercapnia when?

A

fever, sepsis, seizures, exercise, excessive carb loads in diet. only when there is co-existing cardiopulm. dysfunction

15
Q

deadspace ventilation occurs when? examples?

A

when areas of lung tissue are ventilated by not perfused: COPD, asthma, cystic fibrosis, pulmonary fibrosis, thoracic cage abnormalities, etc.

16
Q

minute ventilation refers to? what if it is inadequate?

A

volume of air entering and leaving the lungs per unit time (L/min). hypercapnic failure results if MV is inadequate to excrete the CO2 produced by the body

17
Q

reasons for decreased minute ventilation

A

CNS/resp center depression. spinal cord lesions. peripheral nerve dysfunction. disorders neuromuscular junction. resp muscle weakness. structural abnormalities of the chest/thoracic spine. upper airway, lung or pleural disease.