Have no problem with scenario 2: this happens in real life round our
way. I still have some doubts about the speed of doing a reliable
12-lead in someone's home, or in the back of the bus. If there is kit
availbale in ambos that really can do a reliabel ECG in 2 minutes, then
fine. Better still, the crew let us know if they've got a CLINICALLY
suspicious MI in the back (they are very good at this and doen't slow
down their transport time at all), so we have everything ready as
described in 2 above, but WE do the 120-lead (our gadgets take seconds).
In transit, crew start treatment with aspirin, GTN, oxygen, line.
If paramedics waste time on scene performing a 12 lead ECG then I would
regard this as bad practice. If it can be integrated within normal patient
observations and treatment (IV access with analgesia, BP, O2 administration
while determining the reason for 999 call) then I am all for it. The best
place for a 12 lead is in the back of the ambulance en route to hospital.
If we enter the realms of thrombolysis in the community then he 12 lead
should be performed in the home (location) and thrombolysis administered at
that point in time. Then time delay in taken a 12 lead far outweighs the
time delay in transport to hospital and subsequent door to needle delay
Scenario 3 runs the risk of hypotension and reperfusion arrhythmias in
the back of the ambo en route. Crews CAN cope with this, but may have
to stop to stabilize / defib / tube etc. Is this a justified risk if
gain is ~10 minutes to needle? These sort of side-effects are common
enough that we have a policy that anyone started on lysis in A&E stays
in A&E until finished, rather than be transported 100 yards to CCU with
strep running. Maybe over-cautious, but I would be worried about the
potential problems occuring if lysing en route. If long way to A&E, then
scenario 3 justified.
I agree with the above. Thrombolysis wshould be administered prior to
Check the archives. Helpful Hewlett-Packard staff explained problem to
do with frequency response. In a nutshell: Ambulance monitors
traditionally set to best frequency response to look at rhythm
disturbance, which can give spurious ST elevation. Hospital 12-lead
machines set up to different frequency response which gives reliable ST
changes. I'm sure this is an easily-solved problem to do with set-up of
the kit on ambos. May already have been addressed (Mike Bjorky please
AHA recommends frequency response at 0.05 - 150Hrz. This has been accepted
as industry standard. Where there is conflict in prehospital ECGs are 1. The
12 lead is performed in 'monitor setting' of 0.5 - 40 to 100Hrz. This gives
false positive and false negative printouts. 2. Transiant ECG changes -
Prinz Metal Angina, coronary artery spasm or occlusion which self-terminates
and breaks up and go 'down stream'. The combination of these two account for
some (not all) of the differences seen between pre and hospital 12 lead
ECGs. It is incorrect to state that the prehospital 12 lead is the culprit
as most A&E and CCU units run at the same frequency responce and have
exactly the same software.
None of the prehospital 12 lead units in Sussex have been changed from
standard setup - this includes Marquette 1500 Responders, Lifepak 11,
Cardiofax, MRL and Zoll.