Respiratory Failure and ARDS Flashcards
What are three causes of hypoxemia?
High altitude
Impaired diffusion
V/Q mismatch
In basic terms, what is hypercapnic respiratory failure?
Any process that impairs ventilation
What is the formula for minute ventilation?
V = V(t) x RR
Tidal volume
Frequency
What is the formula for alveolar ventilation?
V(a) = (V[t] - V[d]) x RR
What is the etiology of acute hypoxemic respiratory failure?
Any process that causes V/Q mismatch or limits diffusion to the point that P(a[O2]) is less than 55.
What four things can increase dead space?
Hypovolemia
Decreased cardiac output
Increased airway pressure
Pulmonary embolus
Chronicity of hypoxemic respiratory failure is based entirely on ________.
clinical history
In chronic respiratory acidosis, how much is bicarb supposed to rise for every 10 Torr increase in P(a[CO2])?
4
What two determinants of ventilator oxygenation do we need to know?
FiO2%
Positive end-expiratory pressure (PEEP)
What is the mortality of ARDS?
20% - 30%
At one year after ARDS, most people have __________.
noticeable limitation
How is ARDS treated?
Treat the underlying cause
Supportive care (ventilator management is the only thing that has been shown to increase survival)
Consider prone ventilation in patients with P(a[O2]):FiO2 less than 150
What did the ARMA trial show?
That ARDS patients receiving lower tidal volumes had lower mortality
What did the PROSEVA trial show?
That patients who were prone for part of the day had better outcomes
Only increase tidal volume in ____________.
patients who do not meet ARDS criteria
