Preoxygenation and Prevention of Desaturation
November 8, 2011 by Brian
Filed under All Updates, EMS, ICU, Resus
This paper is an excellent review article citing the cogent relevant evidence for optimal preoxygenation prior to RSI in the critically ill patient. The evidence has been interpreted with pertinent recommendations by two of the world’s heavy hitters in emergency medicine – Scott Weingart and Rich Levitan. If you can get a full text copy of the paper, laminate Figure 3 (‘Sequence of Preoxygenation and Prevention of Desaturation‘) and stick it to the wall in your resus bay!
The points covered include:
- Why preoxygenate? Preoxygenation extends the duration of safe apnoea and should be considered mandatory, even in the crashing patient.
- Standard non-rebreather facemasks set to the highest flow rate of oxygen possible should be used.
- Allow 8 vital capacity breaths for co-operative patients or 3 minutes for everyone else.
- Increasing mean airway pressure by CPAP/NIV or PEEP valves improves preoxygenation. However caution should be used in hypovolaemic shocked patients (decreased venous return) and should be reserved for patients who cannot preoxygenate >93-95% with high FiO2.
- 20-degree head up or reverse Trendelenburg (in suspected trauma) improves pre oxygenation.
- Apnoeic diffusion oxygenation can extend safe duration of apnoea after the RSI. Set nasal cannulae at 15L/min and leave on during intubation attempts. Ensure upper airway patency (ear to sternal notch and jaw thrust).
- Active ventilation during onset of muscle relaxation should be assessed on a case by case basis and reserved for patients at high risk of desaturation (6-8 breaths per minute slowly, TV 6-7ml/kg).
- If there is a high risk of desaturation rocuronium (1.2 mg/kg) may provide a longer duration of safe apnoea than suxamethonium with similar onset time.
Preoxygenation and Prevention of Desaturation During Emergency Airway Management
Ann Emerg Med. 2011 Nov 1. [Epub ahead of print]
Patients requiring emergency airway management are at great risk of hypoxemic hypoxia because of primary lung pathology, high metabolic demands, anemia, insufficient respiratory drive, and inability to protect their airway against aspiration. Tracheal intubation is often required before the complete information needed to assess the risk of periprocedural hypoxia is acquired, such as an arterial blood gas level, hemoglobin value, or even a chest radiograph. This article reviews preoxygenation and peri-intubation oxygenation techniques to minimize the risk of critical hypoxia and introduces a risk-stratification approach to emergency tracheal intubation. Techniques reviewed include positioning, preoxygenation and denitrogenation, positive end expiratory pressure devices, and passive apneic oxygenation.
Thanks so much for the shout-out and the excellent summary!
Cliff and Scott
nice work as always both of you!
My service is replacing vecuronium with rocuronium but still keeping sux for now.
There seems to be increasing literature supporting the notion of just using rocuronium for emergency RSI. The advice in this paper is that it may provide better safe apnoea time than sux with as good onset time and tubing conditions
Do both of you see that rocuronium will replace sux, in ED and prehospital work and that there will not even be a requirement to carry sugammadex…the theory being that in emergency airway management , if they need an airway , the option of waking them up is invalid?
Yes I do think all those things are the case, although one does encounter resistance to giving up sux (just as there is to giving up cricoid pressure). I don’t think the longer apnoea time with roc has yet been demonstrated in critical care so we are extrapolating elective anaesthesia data. As for sugammadex, I also agree with you – more on that here http://resusme.em.extrememember.com/?p=3892
Cliff