Setting the Vent & Problems. 2 Aspects Oxygenation Ventilation.
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Transcript of Setting the Vent & Problems. 2 Aspects Oxygenation Ventilation.
Setting the Vent & Problems
2 Aspects
• Oxygenation
• Ventilation
Initial Settings
• Set mandatory breaths – Pressure or Volume
• Set Assist & Trigger
• Set PEEP and FiO2
• Set Rate
• Set Inspiratory Time
• Set Alarms
• Mandatory Breaths– Pressure – Normal Lungs start about 20cmH2O then titrate to
desired tidal volume.– Volume – Based on IBW – Start at 8ml/kg
• Assist - If Mandatory breaths are Pressure controlled set as (Inspiratory Pressure – PEEP)
• Trigger - 2 (L/min)
• PEEP – Start at 5 if normal lungs, 10 if not
• Rate – 12 unless metabolic acidosis then 15-25
• Inspiratory Time – Go for I:E 1:2
What’s the problem…..?
Causes of High AWP
• Patient– Bronchospasm– Sputum Plug– Coughing
• Tube– Blocked– Bronchial Intubation– Biting
Hypoxaemia (Generally a PO2 of >8kPa is fine)
• Is this to do with the vent settings?
Things that are nothing to do with vent settings should be excluded
first.
• Tension Pneumothorax
• Collapse / Consolidation
• Cardiogenic / Non-Cardiogenic Pulmonary Oedema
Vent Settings
• Oxygenation is proportional to mean airway pressure so can be increased by:– Increasing the inspiratory pressure (keeping tidal
volume <10ml/kg or <7ml/kg if ARDS and plateau pressure <30cm H2O)
– Increasing PEEP– Increasing the inspiratory time (which ends up as
inverse ratio)
• Only if this doesn’t work should FiO2 be increased.
Respiratory Acidosis
• This should be treated to a pH of >7.25 by lowering the pCO2 towards normal.
• If there is also a metabolic acidosis a decision needs to be made on an individual patient basis.
• Hypercapnia is corrected by increasing rate or tidal volume.
Lung Protective Ventilation
• Ventilator induced damage to lungs causes the release of cytokines causing multi-organ failure.
• Possibly only an issue in ARDS
• ARDSnet trial (2000) – Ventilation at 12ml/kg (Pplat <50) vs 6ml/kg (Pplat <30) dropped mortality from approx 40 to 30% with lower Vt.
• ‘Permissive hypercapnia’ unles concerns such as a raised ICP.
Fighting the Ventilator
What does that mean?
Possible Causes
• Not enough sedation
• Not enough analgesia
• Airway obstruction
• Inappropriate vent settings
How would you assess and treat?
•Check vent settings – are you asking the patient to do something unreasonable?
•Check analgesia
•Check for tube blockage
•Assess respiratory system (is there a pneumothorax etc?)
•Would the patient be better spontaneously breathing (with assist)?
•Bolus of sedation
•Muscle relaxation is a last resort.
Ventilator Care Bundle
• Oral hygeine
• Supraglottic suction
• Cuff Pressure monitoring
• Stopping PPIs if no longer required
• Head elevation
• VTE prophylaxis
• Sedation holds (with a view to extubate)