Mech Vent Flashcards
What are potential causes to hypercapneic respiratory failure?
1) Brain - drugs, CVA (ischemia), Bleed/Herniation, structural lesions, metabolic (liver/renal)
2) Spinal curve injury at C3, C4, C5
3) Phrenic nerve injury - GBS, Myasthenia gravis
4) Trachea problem (obstruction)
5) Chest wall problem - kyphosis
6) Pleural space - effusion, ptx
7) Small airway - asthma, COPD
8) Muscle - myositis
What is the approach to a hypoxemic patient?
1) Increase FiO2 to 1
2) Optomize PEEP
3) Switch to pressure control mode
4) Increase RR
5) Recruitment manoever
6) Prone patient
7) Increase Ti time (Reverse IE)
8) Ecmo
What are the 5 causes of hypoxemia?
1) Hypoventilation
2) V/Q mismatch
3) Right or left shunt
4) Diffusion abnormalities
5) Decreased FiO2
What are the goals of CCP Practice?
1) Preserve life
2) Prevent deterioration
3) Promote healing
What is myasthenia gravis?
Autoimmune disease that causes muscle weakness through destruction of nicotinic receptors.
Symptoms affect eyes (ptosis), face and swallowing.
What is Guillain-Barre syndrome?
Autoimmune disorder in which the antibodies cause weakness secondary to peripheral nerve demyelanation
What are 3 causes of myositis?
1) Trauma
2) Infection
3) Autoimmune
What are 5 reasons why we would want to mechanically ventilate someone?
1) Oxygenate
2) Ventilate
3) Protect airway
4) Clinical Course
5) Uncompensated shock
What is the formula for Venous Return?
(Mean systemic filling pressure - Pressure in Right Atrium) / Resistance
With respect to right heart failure, why was Rivers protocol killing people?
Fluid overload increased CVP (right atrial pressure) to the point that there was no passive venous return possible
Describe each of the west lung zones and some causes
Zone 1 -> V > Q (overdistended lungs)
Zone 2 -> V = Q (ideal)
Zone 3 -> V < Q (Infection, edema)
How does a fluid bolus help a COPD patient before intubating?
COPD patient has lots of west zone 1 due to hyperinflation and this reduces alveolar perfusion - fluid bolus would increase perfusion and try to match V/Q prior to intubation increasing oxygenation
What is the bathtub model of stressed and unstressed volume?
Stressed volume is volume above the drainpipe (flows by pressure increase drain). Stressed volume can be increased by adding fluid, or pressors increase stressed volume by shrinking the bathtub
What is ventilation proportional to?
RR and Vt/VtDS (fraction of deadspace)
Aside from increase PCO2, what is another risk of too low Vt?
Alveolar derecruitment
What is a good starting RR?
10-20, but evaluate the patient intrinsic RR first
What are the formulas for transpulmonary plat and transpulmonary peep?
What values do you want for transpulmonary plat and transpulmonary peep?
Transpulmonary Plat = Plat - Pleural Pressure (Pesophagus end inspiration)
Transpulmonary Peep = Peep - Pleural Pressure (Pesophagas end expiration)
Ideal Tplat = < 25
Ideal Tpeep = 0
What is the purpose of peep?
To keep the alveoli open at end expiration, increasing FRC and allowing for oxygenation. TOO much peak causes west zone 1s and decreased perfusion, too little peep cause alveolar collapse and reduced FRC
What is driving pressure, when is it used and what value would you want it be below?
Driving pressure is Plat - applied PEEP = It is studied in ARDS patients and should be less than 15. If you increase your PEEP and driving pressure decreases, then additional alveoli have been recruited
What does the difference between PIP and Plat represent?
Resistance in the airways (circuit right down the alveoli)
Why is it theorized that lower lung volumes protect ARDS lungs?
Not all lung units are available for gas exchange meaning higher volume will overdistend and damage those units that are ventilated
What type of compliance can you measure with inspiratory hold?
Static no flow state compliance
What happened if driving pressure decreases after increasing peep?
More recruitment of alveoli occurs which lower Pplat
What happened if you increase PEEP and SpO2 decreases? How can you correct this? In what disease state would you not do this though.
You overdistended alveoli causing West zone 1 and decreased perfusion. Correct by providing fluid to decrease west zone 1. Do not do this in heart failure
How does a patient die with dynamic hyperinflation?
Dynamic hyperinflation causes massive pulmonary pressure reducing venous return to the RA and the resultant drop in preload causing a drop in cardiac output
When do you need to use peep matching?
When a patient is unable to trigger the vent due to high autopeeps
