Ventilator management for the Neuro ICU 

- Neuro patients are typically intubated for airway protection from decreasing mental status, and not for intrinsic heart or lung disease. Many neuro ICU patients have (relatively speaking) good cardiopulmonary function and reserve.
- The priorities of the neuro ICU are to optimize brain perfusion even at the cost of large insults to the other organ systems.
- Those with increased ICP are most threatened by hyponatremia and CO2 retention, and the goal will be to avoid these events - i.e. under no circumstances do we allow permissive hypercapnea in these patients, even though it may be beneficial to the lungs.
- NB about CO2 and ICPs: CO2 should not be allowed to drop any lower than 25-28, below that you start getting ischemia.
- NB#2: hypocapnea only works to lower ICP temporarily, it doesn't work forever.

Full support: A/C aka volume control 
- Vent delivers preset tidal volume for machine-initiated and patient-initiated respirations
- That's problematic because it can lead to the CO2 being blown too low - i.e. in those with central hyperventilation. Remember minute ventilation = RR * TV
- If you want to enforce the vent settings, you have to really sedate people - i.e. to prevent overbreathing
- Start settings: Rate 14 (titrate to goal PCO2), TV 450 (small = lung protective), FiO2 40% (100% at intubation, titrate down to 40 asap), PEEP 5 to overcome resistance of circuit.
- Titrate PEEP and FiO2 if the sats/PO2 sucks, titrate rate and TV if pCO2 sucks.
- Other disadvantage of full support vent - diaphragm atrophy, difficulty upon weaning.

Less support: SIMV +/- pressure support
- Delivers set TV for machine-initiated respirations, delivers either no support for patient-initiated respirations (SIMV only) or delivers pressure support for patient-initiated respirations (SIMV+PS)
- At most places that I've worked at, when someone talks about "SIMV" they are talking about SIMV+PS.
- Start settings: Rate 10, TV 450, 40% FiO2, PEEP 5, PS 5.

Least support: Pressure support 
- No rate, no TV, only FiO2, PEEP and PS
- All breaths are patient initiated.
- Settings: 40% FiO2, PEEP 5, PS 5