An Anaesthetist from a provincial hospital has a 20 year old man with suspected fat embolism syndrome following an isolated femoral fracture that was repaired earlier that day. The patient has become increasingly hypoxic and difficult to ventilate, but transfer to a metropolitan centre has been delayed for 12 hours due to bad weather.
His arterial blood gases on SIMV mode of ventilation are as follows: FiO2 1.0, pH 7.21, PaO2 65 mmHg (8.6 kPa), PaCO2 72 mmHg (9.3 kPa), HCO3 28 mmol/L. He has a four quadrant infiltrate on his chest X-Ray.
Outline the advice that you would give to help your colleague manage this patient’s ventilation.
• Confirm Diagnosis
- ARDS criteria: CXR, PF ratio, Etiology, no overload
• exclude other etiologies - where is the ETT (not RMB), no pneumothorax, aspiration etc.
• What ventilator is he using, are you familiar with it’s modes (such as pressure control, volume control)
• Ventilatory strategy –pressure and volume limitation to minimise barotrauma)
• PEEP increments to effect, ensuring Plateau Pressure < 30 cm H20
• Heavy sedation and paralysis to minimize O2 consumption and CO2 generation to GCS 3 and no spontaneous ventilation
• Targets for ventilation SpO2 > 90-95 and PO2 > 60
• permissive hypercapnia as long as pH > 7.1
• prone position probably not appropriate (if staff not experienced)
• recruitment manoeuvres
-CVP only to ~PEEP+2 as maximum
- consider frusemide if CVP PEEP +5
-use inotrope to maintain MAP > 60 - suggest noradrenaline
-Transfuse only for Hb approaching 7
• Reassure him and make yourself available for advice 24/7 (Mention of NO, liquid ventilation, surfactant, TGI – no role in this setting)
This is a pretty realistic scenario; as if you were on call and managing a patient over the phone, giving advice to your registrar.
The patient is acidotic, hypoxic and hypercapneic.
What do you do?..
Initial ventilator strategy:
Additional ventilator manoeuvres to improve oxygenation:
Non-ventilator adjunctive therapies for ARDS:
Ventilator strategies to manage refractory hypoxia
Non-ventilator adjuncts to manage refractory hypoxia
Note how useless it would have been to digress into specifics of management for fat embolism syndrome.