Ventilator Strategies

Lung protective and obstructive vent strategies for the critical care transport environment.

Transcript

1. Ventilatory Management FFL Residency Program 2013
2. FFL Approach —  Use ABG to guide therapy, correlate with EtCO2 —  Bundle: HOB 30-deg, cuffed ETTs, volume based on IBW, —  Just two strategies of ventilation 1.  Lung Protective 2.  Obstructive
3. Ventilation is all about CO2, and is corrected with minute volume (RR x tidal volume) Oxygenation is all about O2, and is corrected with mean airway pressure (FiO2 and PEEP)
4. Acute Lung Injury & ARDS
6. 2 subsequent meta-analyses 10 randomized studies Lower tidal volume strategies confirmed repeatedly Save one life every 11 patients by using lower tidal volumes +
8. STRATEGY 1
9. TIDAL VOLUME: protection RESPIRATORY RATE: ventilation PEEP/FiO2: oxygenation
10. PEEP THE GOOD, THE BAD, AND THE UGLY
11. The good —  Improves V/Q match —  Decreases shunt —  Decreases atelectasis/recruits alveoli —  Supports and increases FRC —  Keeps terminal bronchioles open to prevent air trapping PEEP
12. THE BAD —  May decrease venous return —  May need more fluids PEEP
13. UGLY MYTHS —  PEEP causes a pneumothorax —  PEEP makes their head explode PEEP
14. Airway and Alveolar Pressures High airway pressures by themselves are not particularly harmful, unless it reflects high alveolar pressures —  Airway pressure = (flow x resistance) + (alveolar pressure) Detrimental effects of high alveolar pressures, that are incorrectly associated with high airway pressures: —  Barotrauma may result in acute lung injury (leading to ARDS) —  May cause pneumothorax, pneumomediastinum —  Excessive intrathoracic pressure causes hypotension
15. How do we estimate alveolar pressures? —  Inspiratory hold maneuver —  Flow is reduced to zero and airway/alveolar pressures equalize
16. Why do airway pressures matter then? —  High airway pressures (PIP) may result in inadequate ventilation. —  Gives us an indication of airway resistance (bronchospasm) Airway pressure = (flow x resistance) + (alveolar pressure) —  PIP <30 means alveolar pressure <30 —  Can decrease flow by slowing RR or extending I-time
17. PIP = Airway Resistance Pplat = Alveolar Pressure Goal: PPlat <30
18. The P/F Ratio —  PaO2 divided by FiO2 —  100 mmHg / 0.5 = 200 —  80 mmHg / 0.21 = 381 —  P/F Ratio <300 = ALI (Acute Lung Injury) —  P/F Ratio <200 = ARDS scorecard of oxygenation:
19. STRATEGY 2
21. ê RESPIRATORY RATE é EXHALATION TIME TOLERATE HYPERCAPNIA
22. Obstructive Strategy Summary —  Consider compensating for autoPEEP —  If sudden hypotension, disconnect circuit and allow exhale —  Sedate! Permissive hypocapnea is painful
23. If your patient is Crashing: —  Take the ventilator out of the equation: bag the patient to feel compliance first-hand —  Check the tube: displaced, obstructed, deflated —  Check the patient: pleural slide via ultrasound, needle decompression —  Check the ventilator —  If obstructive: disconnect circuit and allow patient to exhale. Use fluids to increase preload.