subgroup settings Flashcards
What are some specific patient subgroups
- COPD
- neuromuscular
- asthma
- closed head injury
- acute respiratory distress syndrome (ARDS)
- acute cardiogenic pulmonary edema (CHF)
What is the R and C in COPD?
increase resistance and compliance
What is the goals when ventilating COPD?
- reduce WOB
- increase pt-ventilator synchrony
- long and complex wean
which modes are suitable for COPD?
PC- CMV or DC-CMV
- descending flow waveform better match patient flow demand
- allow longer E time
VC-CMV
- need to match patient demand
- use decending ramp to avoid high pressure and maximizing distribution of ventilation
What is the tidal volume range for COPD?
5 - 8 ml/kg
What is a precaution for COPD patient?
monitor for Autopeep
How to reduce chance of autopeep?
- lower VE
- permissive hypercapnea
- bronchdilators
- optimal E time
What is the PaCo2 accept for these patient?
normal paCo2 : 50 - 60 mmhg
What is the normal PaO2 for these patient?
55 - 75 mmhg
Why not use PSV for COPD patient?
- patient is controlling the trigger and cycling meaning:
1. I time can be too short or long
2. can increase WOB and poor patient ventialtor synchrony
What is the deal with neuromuscular disease?]
patient have normal:
- ventilatory drive
- normal or near to normal lung function
- require mechanical venilation because of respiratory msucle weakness
What can respiratory muscle weakness lead to?
- limits patient ability to cough and clear secretion
- result: develop atelectasis and pneumonia , broncho-hyigene problem
What is the ideal setting for NM?
Vt: 7 - 8ml/kg
mode: VC-CMV, with higher flowrate
weaning: straight forward
What are the indication of ventilating Asthma patient?
- exhaustion
- ->RR decrease
- ->decrease ph, increase Paco2
- ->respiratory acidosis superimposed on metabolic acidosis - poor air entry
- ->bilateral wheezes
- ->air trapping increases - severe hypoxemia
- ->refractory hypoxemia - depression of hemidiaphrams
- ->air trapping - altered mental state
- -> decrease LOC - dysrthymias
- cardiac or resp arrest
What are the ventialtor settings for asthma?
Fio2: as needed as long as it keeps Pao2 above 60
permissive hypercapnea: allow but watch ph because there maybe underlying metabolic acidosis
I:E: allow for longer E time
Vt: 4 - 8 ml/kg
What is a closed head injury?
- brain injured but skull remains intact
- swelling of the brain leads to increase IP
What is the formula of CPP?
CPP = MAP - ICP
What happens to the CPP when there is a closed head injury?
due to increase in ICP, assuming no change in MAP, the CPP will decrease
What does brain do when the CPP drops?
it decreases the CVR to increase the flow of blood
what is the normal ICP?
less than 10 mmhg
What is iatrogenic hyperventilation?
deliberate lowering of
PaCO2
what is the effect of reducing PaCo2?
- result in cerebral vasconstriction, thus decreasingg ICP
Whhat is the relationship between ph and CVR?
increase ph will increase CVR, decreasing the ICP
What is another effect of increasing CVR
increase CVR decrease the blood flow reach to the brain–> decrease CPP
What is the current recommendation for close head injury?
- PaCO2 < 35 mmHg is not recommended during first 24 hours because CBF is already lessened
- It may be helpful for brief periods of time when ICP rises or until other measures can be instituted to decrease ICP
- In normal ICP settings, hyperventilation should not be used
- All attempts should be made to decrease Paw (low PEEP, moderate VT)
What are the ventilator settings for close head injury?
Mode:
- Full support is needed (VC, PC, DC CMV)
VT:
- 5-8 mL/kg and keep Pplat < 30mm
MV:
- to keep PaCO2 ~35mm,
- target 30 - 35 mmhg if necessary
Keep PaO2 70-100mmHg
What is the primary strategy when treating ARDS?
- Employ lung protective strategy
2. keep pplate <30mmhg withh adequate oxygenation
what are the settings for ARDS according to the guidlines?
VT: initially 8 ml/kg and titrate down from there, depending on Pplat
–> If 4 mL/Kg still causes high Pplat then allow for permissive hypercapnia (pH as low as 7.20)
RR: as high as possible without causing autopeep
Flow: higher flow to reduce I time
Why is Peep important for ARDS?
Prevents atelectrauma, improves shunt, improves compliance
What is the optimal peep for ARDS?
be just above the inflection point on the deflation limb of a PV curve after the lung is maximally recruited
What is the purpose of putting ARDS patient in a prone position?
improve V/Q, improve oxygenation
how to position patient if they have unilateral lung disease (alveolar consoldiation)?
put the good lung down
–>gets better ventilation and gravity dependent lung always get better blood flow
