Jan 21, 11 02:06AM
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An interesting editorial published a couple of months ago in Anaesthesia by Neil Soni. It adds to the growing disquiet that our understanding of disease, and attempts to find effective remedies, are being hampered by the tendency to treat all organ failures equally. I agree that there seems little reason to believe that meningococal sepsis [...]
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Sign in nowchecked out bmjupdates.com. good website. for all those who are waiting to rubbish another study here is one for you
They compared standard care with (std care + cpap) for pts with severe respiratory distress in COMMUNITY.
71 pts in total, CPAP reduced intubation rate and mortality. Alright then- over to you now- go for it
Does anybody have access to Ann Emerg Med?
Thompson J. Out-of-hospital continuous positive airway pressure ventilation versus usual care in acute respiratory failure: a randomized controlled trial. Ann Emerg Med. 2008 Sep;52(3):232-41, 241.e1. Epub 2008 Apr 3
Link to pubmed abstract here
Milind
PS I’ve changed this to comment from an original post by Milind, as at present we can’t get to the original article, which makes critical appraisal of it tricky! Hope that’s OK. Thanks for highlighting it – cheers Ed (Dan)
I noticed that IVIG is recommended by the DOH for the treatment of MRSA PVL necrotising pneumonia (in this useful review). I guess the basis for this will be grade D or at best C evidence. So treatments remain in the guidelines on the basis of case series or uncontrolled trial evidence for specific rare sub types of conditions, but are rejected for broader condition definitions. This appears to me to be a double standard.
The above papers are making waves outside of the medical establishment (as they should), see this article from the Economist which discusses the legal position, and upcoming religious discussion over non-heart beating donation.
Although I wasn’t at the meeting (sorry to have missed it), I would add that determining adequate power for ROC curve generation is tricky. They presumably included all those who died in the negative outcome group as well James ?
This is a provacative paper that’s for sure. The mortality benefit probably reflects decreased barotrauma in the paralysed group — the rates of pneumothorax in the 2 arms was 11% for control and 4% for neuromuscular bloackade.
However there are alot of questions to answer:
- could increased analgesia/ sedation have reduced the rates of pneumothorax in the control group?
- how plausible is it that 2 days of paralysis would result in such marked survival benefits? What is the mechanism?
- although 90d survival was measured, muscle weakness was only assessed up to 28d – are there delayed cases of critical illness polynuropathy being missed?
- How was the adequacy of blockade assured in the absence of train-of-four testing?
- could the benefit be a property of cis- atracurium rather than neuromuscular blockade?
- is the blinding of this study suspect? If the NMB group is fully paralysed only the control group would trigger ventilations, thus breaking randomisation.
- How was ventilator dyssynchrony dealt with? This is not described in the paper – could this be killing patients?
- Was volume-control ventilation appropriate? The patients in this study were sick – PaO2:FiO2 of 100, compared with about 150 in the ARDSNet study where they got their ventilation protocol from. Patients were excluded if they had refractory hypoxemia in the ARDSnet study. The low-volume ventilation protocol may not suitable for these severely-effective patients. Although, similar rates of barotrauma were seen in the ARDSnet study.
- how does this apply to other ventilation modes like APRV that tend to be used in severe ARDS these days?
Cheers,
Chris Nickson
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Thanks for great comments Chris. I aggree the paper poses more questions than answers. It’s interesting that despite pneumothorax rates being different, plateaux pressures were equal in both groups. Are we using the wrong parameter when assessing the applied pressure?
Has this paper changed your practise? It has changed mine, starting paralysis now means an infusion (ideally 48hours) rather than bolts dose.
Hi Dan,
Interesting point on the plateau pressure – will be interesting to see if it’s borne out in other studies. Don’t have a great answer!
Don’t think this changes practice – in severe ARDS I wouldn’t be using volume-controlled ventilation – more likely to use APRV. Was using NMBs anyway if absolutely required – though not so much as an infusion, though its clearly an option if needed (not routine).
It seems to offer some reassurance that it is OK to use NMBs if needed, given the unchanged rates of polyneuropathy at 28d.
Cheers,
Chris
We commonly leave on pressure control, but inverse I:E ratios (which is therefore essentially APRV) or oscillate, so take you point that the trial may not be applicable.
The reason for moving to an infusion over a bolus is that the control arm in the trial were allowed open label bolus atricurium (which mirrors my previous practise) and did worse. We’ve stopped short of making a 48hour infusion routine, although we are considering it on the basis of this trial.
I wonder if ANZICS will do us the usual service of running a properly powered RCT and disproving the initial positive european study!
The link doesn’t seem to work…. bear in mind that I am on a trust PC!!
[...] Are our attempts to find effective remedies, being hampered by the tendency to treat all organ failures equally? This is just one of the question asked in an excellent post, looking at The Pinocchio Effect. [...]
Link should work now James, seems pubmed have yet to catch up and give this a full slot.
I know it’s been a while since the last post, it’s been a very busy few months! Hopefully will be able to post more frequently on Critical Insight over the next few months.
Dan, very thoughtful analysis. Death within 48hrs is pretty heavyweight endpoint. Clearly this was a very ill cohort. I do think is worrying that an intervention that would “normally” be expected to improve a physiological derangement doesnt necessarily help. The use of norepinephrine appears to have lasted longer than most, but many rapid interventions do seem to cause trouble…i hastened the demise of a few people with mechanical ventilation, correction of electrolyte and pH
This is a wonderful demonstration of the harm of volume controlled ventilation, and how paralysing patients allows you to use this mode fractionally more safely – the mortality and pneumothorax rates are horrifying and unacceptable, especially considering that the average P/F ratios and FiO2 and PO2 averages demonstrate generous (over) oxygenation, underPEEPing and really not very sick lungs, despite the high mortality rate!
The fascinating piece of information is the HEAVIER use of sedatives, and in particular Ketamine in the NMBA group!
Morale of this study – don’t use volume controlled ventilation strategies (note no mention of use of PRVC/VC+/Autoflow, which would be a lot better)
[...] can register and submit their own posts. The blog most recently featured the provocative topic of NMB in Early ARDS. Free Emergency Medicine TalksA great talk by Mervyn Singer called “Less is More in [...]
The Pinochio effect – trials on even well defined disease entities stratified for age and severity will become even more difficult when genetic polymorphism needs to be taken into account. Look at the paper by Lord darzi in this weeks NEJM if you’re intetrested