Test Flashcards
(23 cards)
How does increased intrathoracic pressure affect the brain?
Restricts blood flow from the brain back to the heart.
What factors affect cerebral perfusion pressure (CPP)?
MAP & ICP
CPP decreases if there is a decrease in MAP or an increase in ICP.
Explain how an increased ICP affects the brain.
Causes brain trauma and correlates with poor outcome.
What is cerebral autoregulation and what is the normal range?
The ability of the cerebral arterioles to constrict and dilate to maintain CPP. Normal range is 60-150 mmHg.
How does CO2 affect ICP and why is hyperventilation useful with closed head injury patients?
Decrease CO2 leads to increased CSF and vasoconstriction, which decreases ICP.
How does PPV affect urine output?
Decreases it by 30-50%.
What is the mechanism by which PPV decreases urine output?
Increases intrathoracic pressure causing decreased urinary output by increasing ADH and decreasing natriuretic hormone.
How does PPV affect the liver?
Decreases perfusion to liver causes decrease in CO and increase in serum bilirubin levels.
What does decreased Gl function lead to?
Gl bleeds, stress ulcers, and gastric distention.
How can decreased Gl function complications be minimized?
Use of prophylactic drugs if patient on a vent for > 48 hrs and NGT for gastric distention.
Define VALI and VILI.
VALI - Vent-associated lung injury due to high pressures; VILI - Vent-induced lung injury due to volutrauma, biotrauma, & atelectrauma.
What is the difference between barotrauma and volutrauma?
Barotrauma - excessive pressure (PIP); Volutrauma - excessive volumes (Vt).
Name the four types of barotrauma.
- Pneumothorax
- Pneumomediastinum
- Pneumopericardium
- Sub Q Emphysema
What is atelectrauma and how can it be corrected?
Recruitment and decruitment of alveoli. Can be corrected with open lung and decremental PEEP strategy.
Define biotrauma.
Biochemical injury or release of inflammatory mediators (cytokines).
How do you minimize auto-PEEP?
Decrease Itime, increase Etime, increase insp flow, increase PEEP.
What is oxygen toxicity?
Tissue damage with increased A/C permeability, associated with FiO2 > 60% for > 24-48 hrs.
How do you prevent VAP?
- Gentle suctioning
- Use MDI instead of SVN
- Keep HOB at 30-45*
- Avoid breaking vent circuit
- Drain tubing condensation
- Wean to extubate ASAP
What should you do if there is a ventilator malfunction?
Take the patient off the vent and use manual ventilation (Bag them).
Given a respiratory rate of 14 bpm and an I:E ratio of 1:3, what is the total cycle time?
4.28 seconds.
Given a respiratory rate of 14 bpm and an I:E ratio of 1:3, calculate the inspiratory time.
1.07 seconds.
Given a respiratory rate of 14 bpm and an I:E ratio of 1:3, calculate the expiratory time.
3.21 seconds.
Given a respiratory rate of 12 bpm and an I:E ratio of 1:5, what is the total cycle time?
5 seconds.
