Acute Resp Failure Flashcards
hypoxemic RF due to?
inadequate oxygen delivery
hypercapnic RF due to?
respiratory acidosis
name 5 causes of hypoxemic failure
decreased PIO2 (altitude, plane), decreased alveolar ventilation, VQ mismatch, R to L shunt, diffusion limitation
decreased alveolar ventilation has what effect on PACO2 and PAO2
increases PACO2, decreases PAO2
acute hypercapnea from drug overdose causes an increased PACO2, resulting in?
decreased PAO2
what effect does oxygen therapy have on dead space
no effects
the only physiological cause of oxygen diffusion limitation is?
exercise (due to fast blood flow and insufficient time for diffusion)
three ways to increase PaCO2 (hypercapnia)
increase VACO2, decrease minute ventilation, increase dead space
name two situations where you have an increased VACO2
fever, trauma
name two situations where you have an increased dead space
PE, emphysema
what are some common causes of decreased minute ventilation?
drug overdose (decreased resp drive), nerve conduction abnormalities, neuromusc dz, chest wall abnormalities, lung disease, upper airway obstruction
a high pCO2, low pH, and normal bicarb indicate?
acute failure (resp acidosis)
a high pCO2, close to normal pH, and high bicarb indicate?
compensated failure (chronic retention of CO2 such as in COPD)
a super high pCO2, low pH, and high bicarb
acute AND chronic failure
be careful giving oxygen to someone with high CO2 retention because?
they have changed their set point (carotid body receptors for O2) and oxygen therapy can cause them to stop breathing – give them a lower dose
late stage respiratory failure from muscle weakness can present with?
hypercapnea
signs of resp mm weakness
tachypnea, decreased vital capacity, decreased inspiratory force, ineffective cough
treat resp mm weakness with?
support ventilation
treatment for hypercapnic failure:
- underlying cause, 2. resp stimulants, 3. assist devices, 4. tracheal intubation & PP ventilation, 5. mechanical ventilation
name 2 current types of assist devices
nasal/face CPAP (cont positive airway pressure), BiPAP (pressure in and out)
4 ventilatory controls
- breath initiation/RR, 2. tidal vol/pressure, 3. patient reg’n, 4. PEEP (a little air to prevent collapse)
how does PEEP affect FRC?
it is increased
adverse effects of PEEP
barotrauma from increased intrathoracic pressure –> decreased venous return –> decreased cardiac output
low pH, low CO2, and low bicarb sign of?
metabolic acidosis!
