Modes of Oxygen Delivery¶
Blake Funke
| System | L/min | % O2 | Comments |
|---|---|---|---|
| Blow by (ex: Trach collar) | 21-100% | ||
| Nasal cannula | 1-8 | 25 – 45% | |
| Large bore nasal cannula | Up to 15 | Up to 65% | Can be identified by larger bore tubing (often green) and nose piece. Colloquially referred to as HFNC at VUMC, but true HFNC = optiflow |
| Venturi mask | 4 to 15 | 24 – 50% | Actual FiO2 is dependent on pt effort |
| Non-rebreather | 10 to 15 | 65-95% | Often used as a bridge to higher level of O2 therapy |
| HFNC: Optiflow, AirVo, Vapotherm | Up to 60 | 30-100% | Delivers 0.5-1 cm/H2O of PEEP per 10L of flow |
** Use of all of the above modes of O2 requires a spontaneously breathing pt
Non-invasive positive pressure ventilation:¶
- CPAP
- Indications: obstructive sleep apnea, tracheomalacia
- Settings: CPAP, FiO2
- BiPAP
- Indications: hypercapnic respiratory failure (RF), hypoxic RF, pulmonary edema, obstructive sleep apnea, obesity hypoventilation syndrome, RF 2/2 neuromuscular disease
- Settings: IPAP, EPAP, FiO2, RR (sometimes)
| Mode | You set | Not set | Comments |
|---|---|---|---|
| Pressure support (PS) | PEEP PS above PEEP FiO2 |
TV RR Inspiratory flow |
Similar to Bipap. Frequently used for vent weaning / SBT. Requires spontaneously breathing pt |
| Volume Control (AC/VC) | PEEP RR TV Inspiratory flow FiO2 |
Inspiratory pressure | Mandates a minute ventilation; limits volutrauma (i.e. can guarantee low tidal volume ventilation) **Primary mode used in MICU (mode used in major ARDS trials) |
| SIMV (Synchronized Intermittent Mandatory Ventilation) | PEEP RR TV PS above PEEP FiO2 |
Pt gets VC breath for set rate, but if tries to breath over this will get PS breath; VC and PS breaths are synchronized when able | |
| Pressure Control (AC/PC) | RR Inspiratory Pressure PEEP Inspiratory Time (or I:E ratio) FiO2 |
TV | Minimizes barotrauma (i.e. sets a max inspiratory pressure) → does not guarantee a specific minute ventilation (must monitor PCO2 with blood gases) Does not have natural ventilator alarms for protection – need to increase low minute ventilation alarm threshold |
| PRVC (Pressure Regulated Volume Control) | PEEP RR TV Inspiratory flow Pressure max FiO2 |
Adaptive pressure control (NOT actually a volume control mode); tries to limit both barotrauma and volutrauma but if in conflict, minute ventilation will drop (i.e. need to monitor PCO2 with blood gases like any other PC mode) Con: More the pt works, the less the ventilator does |
|
| APRV / Bilevel | PEEP (PLow) Pressure High Time Low Time High FiO2 |
TV | Long periods of inspiratory holds and very brief expirations (i.e. releases), for refractory hypoxemia. Often difficult to ventilate pts on this mode |