2021-10-01-micu-morning.md (1452B)
1 # Pre-intubation 2 3 Presented with O2 sat 81% to the ED, what's next? 4 5 ## NC 6 7 Max flow through standard NC ~6L/min. 8 9 ~3-4% increase in FiO2 per L, so 2L/min ~= 30% FiO2. 10 11 Minute ventilation ~5L/min if assume 10 breaths per minute, 12 ~500mL tidal volume, 13 but: 14 - those are averaged over one minute 15 - moment inspiration will exceed that flow rate, 16 - the seal isn't perfect, 17 18 we're typically putting O2 on dyspneic people, 19 so those assumptions typically do not hold. 20 21 ## Large-bore NC 22 23 Bigger tube, up to ~15L/min. Otherwise same as NC. 24 25 ## Venturi mask 26 27 Size of holes determines rough amount of entrainment. 28 29 ## NRB 30 31 One-way exhale valves, bag w 100% O2. 32 Still getting some entrainment, but overall higher O2 delivered. 33 34 ## HFNC 35 36 Optiflow, Airvo, etc. 37 38 Up to 60L, 100% FiO2. 39 Humidified air, 40 more complete seal on nose piece. 41 Less complications from dry air (massive epistaxis), 42 less entrainment (though depends on if their mouth is closed). 43 Also provides up to ~5L PEEP. 44 45 Blends 100% O2 and medical air to achieve the set FiO2. 46 47 [FLORALI trial](https://www.nejm.org/doi/full/10.1056/nejmoa1503326) 48 - intubation rate between HFNC and NIPPV was not different (primary outcome) 49 - ventilator free-days were different (higher in HFNC) 50 - 90d mortality rate better for HFNC than NIPPV 51 52 # NIPPV 53 54 Pressure increase (mean airway pressure), 55 more O2 exchange d/t greater partial pressures of delivered O2 56 over more time. 57 58 # Invasive ventilation 59 60 Next week...