Ventilation Specifics: Normal Lungs / Lung Injury (Pneumonia/ARDS)
Ventilation is frequently commenced in the Emergency Centre following intubation. The following suggested principles for specific medical conditions are based on the pathophysiology of the condition and settings should be tailored to each patient individually.
Two large groups of patients will be ventilated in the EC, the patient with obstructive lung disease (COPD / Asthma) and patients with lung injury or patients susceptible to lung injury (Pneumonia / ARDS.) For each of these groups basic ventilator principles are suggested.
Normal Lungs
| Mode: | Assist Control (A/C) or SIMV |
| Tidal volume (Vt) | 6 ml/kg (predicted body weight.) Range 6-10 ml/kg |
| Inspiratory Flow Rate (IFR) | 50-70 litre per minute |
| Rate (RR) | 12-14 (10-20 bpm) |
| Insp. Pressure | 10-30 cmH2O (titrate to Vt in pressure cycled ventilation) |
| PEEP | 3-5 cmH2O |
| FiO2 | 1.0 (100%) wean to below 0.6 (60%) asap |
| Pressure Limits | Plateau airway pressure (Pplat) of < 30 cm H20 |
Lung injury (Pneumonia / ARDS)
Lung protective ventilation strategies have been shown to be superior in these patients – ARDSNET 2000. Strategy is to reopen alveoli (recruitment) and keep alveoli distended but not over-distended using high PEEP and low tidal volume (Vt.)
| Mode: | Assist Control (A/C) |
| Tidal volume (Vt) | 6-8ml/kg (predicted body weight.) ARDS aim for 6 ml/kg |
| Inspiratory Flow Rate (IFR) | 60-80 litre per minute |
| Rate (RR) | 18 (16 – 24; titrate acc to PaCO2 and allow permissive hyper-capnoeatitrated to pH 7.20) |
| FiO2/PEEP | 1.0 (100%) wean to below 0.6 (60%) asap. PEEP 8 – 15 cmH2O (titrate to paO2 > 7.2 or SaO2 88 -92%) Titrate PEEP and FiO2 to achieve goal. (ARDSNET tables available for guidance in this regard) |
| Pressure Limits | Plateau airway pressure (Pplat) of < 30 cm H20 If Pplat > 30 cmH2O decrease Vt by 1 ml/kg (min 4ml/kg) If Pplat < 25 cmH2O & Vt < 6 ml/kg increase Vt by 1ml/kg till Pplat > 25 cmH20 or Vt 6 ml/kg |
Use sedation and analgesia to optimise patient comfort and improve patient ventilator synchrony.