2022-05-09-vents.md (1453B)
1 # vents 2 3 Alex Dragnich 4 5 6 ## overall 7 8 Art Wheeler (paraphrased) - the best mode of ventilation is the mode you know best. 9 10 11 ## knobs 12 13 Many! 14 - FiO2 15 - rate(t) 16 - Pi 17 - PEEP 18 - I:E ratio 19 - TV (Vt) 20 - etc. 21 22 but really: 23 - FiO2 24 - triggers 25 - Q (flow) 26 - C (cycle) 27 28 and cannot perfectly control pressure and volume at the same time, 29 though modes like PRVC attempt to strike an automated balance. 30 31 oxygenation: FiO2 (directly) and PEEP (via mean airway pressure) 32 33 ventilation: R(t), Vt, Pi 34 35 36 ## APRV 37 38 Type of inverse ratio ventilation, 39 based on time constants of collapse/expiration. 40 41 e.g. expire ~75% of TV in a time constant. 42 43 44 ## SIMV 45 46 supported intermittent mechanical ventilation. 47 48 Background of VC at a certain rate, 49 allowed to take supported breaths in between. 50 51 ~CMV w BiPAP 52 53 54 ## AC 55 56 assist control. 57 58 volume control, people are allowed to take breaths and then volume is delivered 59 60 set: Vt, PEEP, R(t), FiO2 61 62 measure: peak inspiratory pressures, plateau pressures, MV, driving pressure (plateau minus PEEP) 63 64 triggers: P or Q (e.g. neuromuscular, may not be able to generate much flow so set pressure trigger, COPD often the opposite) 65 66 cycle: time 67 68 69 ## PC 70 71 set: P(high), P(low), Pi, R(t) 72 73 measure: Vt, V 74 75 triggers: P or Q 76 77 cycle: time 78 79 set a MV alarm (ideally, set at what has been maintaining ventilation for that pt) 80 81 82 ## PRVC 83 84 set target volume, generates pressures, adjusts based on calculation of last three breaths 85 86 is actually pressure control mode