Hi folks!
Mike and Chris sent me this nice up to date review article of critical care air transport. Its mainly North American focussed but covers the broad base of literature on the topic:
Wilcox S, Tollefsen W. Air Transport Of The Critically Ill Emergency Department Patient. EM Critical Care, Vol 2 Num 4, 2012 [Abstract]
Here is the usual LITFL Q&A format to for a quick review of this topic.
Questions
Q1. What is the most common work of air transport teams and helicopter ambulances in Australia and USA?
In one review, 80% of critical care transport team missions were interfacility transfers. Fixed wing and helicopter ambulances undertake the bulk of long distance interfacility transport work in Australia and USA.
Q2. What conditions benefit the most from air transport and critical care transport team management?
Trauma by far and away carries the best evidence for benefit with up to a 33% reduction in trauma related death for the more severely injured patient compared with ground transport. STEMI and air transport to a PCI capable hospital appears to be beneficial as opposed to immediate thrombolysis as long as its timely, although more ALS interventions are needed with air transport within first 24hrs of STEMI.
Q3. Unstable patients are prone to deterioration during air transport due to a number of environmental and physical reasons. What principles can be applied to adequately prepare the critical patient for air transport?
Take a systematic ABCDE approach and consider that interventions during flight are more difficult than on the ground. Stabilise the patient’s physiology as much as possible. All lines, tubes and drains must be secured for considerable movement. Adequate analgesia and/or sedation is crucial for patient comfort as they will be moved multiple times. A systematic clinical handover tool is the single most effective measure in all patient transport scenarios.
Q4. Which patients should not fly?
There are few absolute contraindications but clearly the maxim should be that air transport should provide a reasonable measure of benefit to the patient.
Cardiac arrest patients are unlikely to benefit from air transport but the growing use of mechanical automatic CPR devices may change this notion! Actively labouring pregnant women are considered a strong contraindication to flying but this is dependant upon the local health care facilities and staffing and effective tocolysis may allow air transport to occur without delivery. Agitated combative patients are considered a strong contraindication to flying and careful stabilisation, sedation and restraint need to be applied prior to taking such patients into the air.
Q5. Boyles law tells us that any volume of gas will expand with decrease in ambient pressure. Traditionally this has meant considering endotracheal tube cuffs being filled with saline as opposed to air. Why is this a retrieval medicine myth?
Endotracheal cuffs are designed to be inflated with air. They are tested prior to sale with air. Despite your best attempts, it is almost impossible to remove all the residual air in the cuff. When filled with saline, the residual air will expand and the cuff will grow in volume. Certainly it will not expand as much as if all air is used to fill the cuff. The smart thing to do is measure the cuff pressure regularly during air transport with a portable cuff manometer. It is impossible to do this accurately with a saline filled cuff.
About Minh Le Cong
Hi MInh
We have had a recent debate over the air vs. saline in the ETT cuff.
The official RFDS guidelines say “saline”, but as you mentioned, it seem smarter to monitor pressure and adjust the volume to keep it safe.
Do you have any evidence or reports to back this up?
Is this a regional oddity or common practice in your world?
Casey
retrieval mythbusters courtesy of my Kiwi buddies
http://onlinelibrary.wiley.com/doi/10.1046/j.1365-2044.2002.02464.x/full
we use a standard aneroid cuff manometer, record pressure preflight, during ascent and descent. you need to release air and reinflate etc.
It also allows measurement of LMA mask pressure to recommended levels for flying those annoying post arrest swine you have ventilated
the longer your flight the more reason there is to check your pressures. filling with saline is safer than filling with air if you cannot measure pressures in cuff. Best practice is to measure pressures in cuff.
ETT cuffs are not designed to fill with liquid. Yes it is done , partic in microlaser surgery of larynx where there is riak of fire, but I have yet to read or hear of the case report of microlaser surgery performed during aeromedical retrieval
We dont fill ETT cuffs in ICU, so why on earth start doing this before transporting these ventilated patients to ICU? Are we not aupposed to provide similar level of critical care during transport than that afforded in hospital?
sorry I meant to write We dont fill ETT cuffs with saline in ICU
Liquide is not compressible
And thus unchecked volumetric saline inflation is more likely to be implicated in unacceptably high cuff pressures. (Both, wet or dry cuff scenarioes points to the high importance of cuff pressure monitoring and adjustement.)
Once you accept the concept of cuff pressure monitoring and adjustement
The dry cuff approach is definitely more comfortable and safer to your patient.
You ever transported a patient with Combitube
Or Blakemore ! ! !
DON’T even think of using saline
Charles
Charles I hear ya. You can fly with me anytime!
There is one balloon tamponade catheter we carry that is designed to be filled with saline or water, not air..its called the Bakri balloon, designed for uterine balloon tamponade.
I have yet to use in anger on an aeromedical retrieval so it will be interesting to see how ensuring safe balloon pressure will be achieved going to altitude.
check out this excellent overview of uterine balloon tamponade
http://www.google.com.au/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CEoQFjAA&url=http%3A%2F%2Fwww.obgyn.net%2Feducational-tutorials%2FOB_uterine_vaginal_balloons_PPH-Hennawy%2FOB_uterine_vaginal_balloons_PPH.ppt&ei=J7UmUMSUNOyfiAeh8IHwCg&usg=AFQjCNE-wwLXtfLOIyB0AxjXwm5roZv-QQ
Minh, you talked about a systematic clinical handover tool- do you have one that is available to have a look at or any resources to help design one for our ED handovers,
Thank you
yep this one
https://www.mja.com.au/journal/2009/190/11/isobar-concept-and-handover-checklist-national-clinical-handover-initiative