Acute and Chronic Respiratory Failure Flashcards
What is respiratory failure?
Lungs failing to adequately oxygenate arterial blood or prevents the retention of CO2
What is acute respiratory failure? (time, reversibility)
Abrupt onset of failure within hours to days
Can reverse or become chronic
What is chronic respiratory failure? (time, clinical course, reversibility)
Months to years
Can be insidious
Irreversible
What is the definition of acute on chronic respiratory failure?
- Increased baseline oxygen requirements
- Increased CO2 above baseline to drop pH below 7.3
A pH drop below what level characterizes acute on chronic respiratory failure?
7.3
What is the usual cause of acute respiratory failure secondary to a ventilatory failure?
Drug overdose
What is the usual cause of acute respiratory failure secondary to a oxygenation failure?
Pneumonia
What is the usual cause of chronic respiratory failure secondary to a ventilatory failure?
Neuromuscular disease
What is the usual cause of acute respiratory failure secondary to a oxygenation failure?
Pulmonary fibrosis
What is the failure value of PaO2?
Less than 60 mmHg
What is the failure value of PaCO2?
More than 50 mmHg
True or false: PaO2 varies by age
True
What is normal PaCO2?
40 mmHg
What is the equation for PaO2 to adjust for age?
100.1 - 0.32(age)
What is the most common cause of respiratory failure? Second?
Malignant neoplasm
COPD and related
What percent of patients with AECOPD with admission PaCO2 greater than 50 mmHg will die in the hospital? In 6 months
11% in hospital
33% in 6 months
What are the four classifications of respiratory failure?
- Hypoxemic respiratory failure
- Hypercapnic respiratory failure
- Perioperative
- Shock
What is hypoxemic respiratory failure d/t?
- R-L shunt
- V/Q mismatch
- Diffusion defect
What is the cause of hypercapnic respiratory failure?
- Pump failure
- Increased CO2 production
- Deadspace
Blood flow to the respiratory muscles increase by how much in shock? What is the consequence of this?
10x
What are the four major host causes of hypoxemia?
- Hypoventilation
- Diffusion impairment
- Shunt
- V/Q mismatch
What is the major environmental causes of hypoxemia?
Low FiO2
If there is not an increase in PaO2 with oxygenation, what type of pathology should you suspect?
Shunting
What is the usual BP change with tissue hypoxia?
HTN
What are the CV changes late in the course of hypoxia?
Bradycardia
Hypotension
What is the best diagnostic tool to assess the cause of respiratory failure?
H&P
What is the normal A-aa gradient?
Less than 10 mmHg
What is the equation for the age adjusted A-a gradient?
age/4 +4
What is PaO2/FiO2? Why it it useful?
Determines the severity of respiratory failure
What are the mild, moderate, and severe levels of PaO2/FiO2?
Mild 300-200
Moderat 200-100
Severe less than 100
What do B lines on an US indicate?
Pulmonary edema
What are the three interventions that should be obtained with all patients in respiratory failure?
- Oxygen
- IV access
- Vital sign monitoring
What are the four aspects of vital monitoring with patients in acute respiratory failure?
- SpO2
- HR
- BP
- EKG
What is the goal of advanced support for respiratory failure?
Provide adequate oxygen delivery to the tissues
What is the role of vasodilators in CHF?
Reduce workload of the heart
What is the goal Hb level for respiratory support?
More than 7 mg/dL, unless bleeding
What is the goal MAP for respiratory failure?
more than 65 mmHg
What is the amount of IVF that should be administered for advanced respiratory support?
30 ml/kg
What is the goal lactic acid level for advanced respiratory support?
less than 4.0
True or false: assessment and treatment occur simultaneously with respiratory distress?
True
What is ventilatory failure?
Hypercapnic respiratory failure–alveolar ventilation becomes inadequate in relation to CO2 production
Acute changes in PaCO2 developes rapidly enough to decreased pH to less than what level in hypercapnic respiratory failure?
7.3
What are the two major causes of hypercapnic respiratory failure?
- Ventilatory capability (pump failure)
- Ventilatory effort (drive failure)
What is the equation for PaCO2?
K(VCO2/VA) | VA = alveolar ventilation, VE = minute ventilation
VCO2 = CO2 output
What are the three major hypoventilation (drive) causes of hypercapnia?
- Neuromuscular
- Body habitus
- Drugs
What are the causes of increased CO2 production that can lead to hypercapnia?
- sepsis
- burns
- seizures
What are the three major components of the pump that can cause hypercapnia?
- Airway obstruction
- Respiratory muscle issue
- V/Q mismatch
An acute change in CO2 level of 10 decreases pH by how much?
0.08
A chronic change in CO2 level of 10 decreases pH by how much? Why is this different from acute?
0.03
Kidney compensation by increased bicarb
For every 10 rise of CO2 in acute respiratory acidosis, bicarb increases by how much?
1
For every 10 rise of CO2 in chronic respiratory acidosis, bicarb increases by how much?
3
For every 10 decrease of CO2 in acute respiratory acidosis, bicarb increases by how much?
2
For every 10 decrease of CO2 in chronic respiratory acidosis, bicarb decreases by how much?
5
What causes the CNX issues with hypercapnia?
Increased cerebral blood flow
What are the three major clinical manifestations of ventilatory pump failure?
- Dyspnea
- Respiratory distress
- CNX activation
What are the two major clinical manifestations of ventilatory drive failure?
Bradypnea
Apnea
GSC***
What is the lab that is needed for a diagnosis of respiratory distress?
ABG
True or false: intubation and mechanical ventilation aids in airway protection and secretion clearance
True
What are the causes of hypercapnia from oxygen administration? (3)
- Increased V/Q mismatch
- attenuated hypoxic ventilatory drive
- Haldane effect
What is the Haldane effect?
Oxygen released bound CO2 increases PaCO2.
Normal pH with elevated PaCO2 is suspicious for what?
Chronic respiratory failure
What is the treatment for chronic respiratory failure?
- Vaccination
- Oxygen therapy
- Mechanical ventilation
What are the three major vaccines that should be administered to patients with chronic respiratory failure?
- TDaP
- Flu
- Pneumococcal
What percent of middle aged smokers have a sustained cessation effort after 5 year f/u?
22%
What does oxygen administration not improve?
-lung function
Oxygen administration for chronic respiratory failure does not improve survival in what patients?
- Moderate hypoxemia (56-65 mmHg)
- Nocturnal hypoxemia
What qualifies someone for home oxygenation?
PaO2 less than 55 mmHg or SaO2 less than 88%
Patients with a PaO2 or 56-59 with what other factors qualify for home oxygen?
- P pulmonale
- pedal edema
- Secondary erythrocytosis
Is there a survival benefit with pulmonary rehab?
No
What does pulmonary rehab improve?
- Strength
- Weaning outcomes
- Functional status
What is the 5 year survival rate for a lung transplant?
50%
What are the two rate limiting steps for lung transplantation?
- Chronic rejection
- infection
What age do you need to be under to receive a lung transplant?
65
What are the chronic infections that are absolute contraindications for a lung transplant?
- HIV
- Hep C
- Hep B
What type of musculoskeletal disease is an absolute contraindication for a lung transplant?
Kyphoscoliosis
True or false: patients with major organ dysfunctions cannot receive lung transplants
true
True or false: osteoporosis is an absolute contraindication for a lung transplant
False– relative
True or false: BMI greater than 30 is an absolute contraindication for a lung transplant
False– relative
True or false: steroid use is a relative contraindication for a lung transplant
True
What are the PaO2 and PaCO2 findings with: hypoventilation?
Increased PaCO2
Decreased PaO2
What are the PaO2 and PaCO2 findings with: ILDs?
Pure decrease in PaO2 with no change in PaCO2
What are the PaO2 and PaCO2 findings with: ARDS?
Decrease in both PaO2 and PaCO2
What are the PaO2 and PaCO2 findings with: COPD
Increased PaCO2
Decreased PaO2
Similar to hypoventilation, but less severe