Should paramedics be intubating patients pre-hospital
Tony Smith
Outline
Should paramedics be intubating patients pre-hospital?
Tony Smith
Chairman Clinical Advisory Group, Medical Advisor, St John
Intensive Care Medicine Specialist, Auckland City Hospital
A controversial topic
• Airway care and intubation are increasingly controversial in the pre-hospital setting
– Increasing evidence that intubation either makes no difference to outcomes or may even make outcomes worse
– An area where feelings are strong and emotions can run high
– An area with some territorial conflict
• Controversy is also present in cardiac arrest
– Observational studies confirm no consistent survival benefit from intubation in cardiac arrest
– Several services have seen survival from cardiac arrest fall after widespread introduction of intubation
– Reason Is not entirely clear, likely to be multifactorial
• FAT
• Positive pressure in chest causes blood flow to fall during CPR
Should paramedics be intubating patients pre-hospital?
• Focus on intubation in the setting of trauma
• Review why we intubate patients pre-hospital
– Mostly based on theoretical grounds
• Review the evidence for pre-hospital intubation
– The evidence is not very supportive
• Review the evidence for pre-hospital RSI
– The evidence (what little we have) is not very supportive
• Describe our own experience with pre-hospital RSI in paramedic hands
• Finish with some conclusions
• Questions
Imagine a high speed crash…
Imagine a trauma patient…
• Road crash, occupant
• Trapped, 30 min from hospital by road
• Poor airway with trismus, poor breathing, Sats 92% on high flow oxygen
• How should we manage this patient’s airway?
What are our airway options?
• Oropharyngeal airway, nasopharyngeal airway, laryngeal mask airway
• Intubation without drugs
• Intubation with sedation alone
• Intubation with RSI by paramedic
• Intubation with RSI by doctor
• Cricothyroidotomy
• What is the evidence for
intubation?
The evidence
• Pubmed search using terms pre-hospital and intubation, limited to English and the last ten years
• 231 papers
The evidence
• Of these 231 papers only 79 looked at intubation by paramedics
• Of these 79 papers only 14 looked at outcomes
• Of these 14
– Only one paper was randomised
– Only two papers were prospective
– 9 showed raised mortality in the intubated group vs non-intubated
– 3 showed no difference in mortality
– 1 showed lowered mortality in the intubated group vs non-intubated
Why do we intubate trauma patients pre-hospital?
• Observational studies showed increased mortality and morbidity when patients with traumatic brain injury (TBI) were exposed to secondary injury
– Hypotension, hypoxia and hypercarbia
• Intubation promulgated as a good thing
– Control and protect the airway
– Control the breathing
– Allow 100% oxygen to be given
– Allow hypercarbia to be prevented
• Some trauma databases showed reduction in mortality in patients who were intubated pre-hospital
Paramedics took this on board
• Here was an intervention that should help patients
– It was also an exciting intervention and an advanced skill…
• Paramedics took this on board and tried hard to intubate as many patients as they could
• But there were problems
• Many trauma databases demonstrated extraordinarily high mortality rates (90-98%) in patients with severe traumatic brain injury who were able to be intubated without the aid of additional medicines
– Intubation doesn’t change this inherent mortality rate
– The ability to intubate was a marker of mortality
The problems with intubation
• Laryngoscopy and intubation requires patient to be very unconscious with blunted airway reflexes (typically GCS 3)
• Many patients with severe traumatic brain injury have a degree of trismus and relatively intact airway reflexes and these commonly prevent successful intubation
– As a result successful intubation rates in this setting are relatively low (5-30%)
Paramedics were damned if they did and damned if they didn’t
• We thought intubation was a good thing but …
– Those able to be intubated without additional medicines had an inherently high mortality rate that was unchanged by intubation
– Successful intubation rates in the
absence of medicines were very low
– Some services reported increased
success rates with the use of sedation
to blunt airway reflexes
• Perhaps the answer was to sedate
the patient..
Is sedation the answer?
• Sedation might allow airway reflexes to be overcome and thus allow patients (that weren’t so badly injured they were destined to die) to be intubated
• Some allowed sedation (often benzodiazepine plus opiate) to overcome airway reflexes in order to achieve intubation
– Most Australian and New Zealand services allowed this in the past
– There was still low success rate (50-60%) despite repeated doses
– There was a high incidence of hypotension (50%)
• Controversial
– Supporters claiming it was better than doing nothing
– Opponents claiming it was more likely to produce secondary injury that to prevent it
Disappeared in Australasia
• The practice largely disappeared in Australia and New Zealand several years ago
– Multiple trauma data-bases showed an increase in mortality in patients with TBI given sedation
– Mortality even higher if sedated and intubation attempt was unsuccessful
• Clear message: intubation
done badly is worse than
basic airway care done well
• Perhaps RSI was the answer..
• Perhaps the answer was to take complete control
• Some services introduced RSI in paramedic hands
• Usually some form of sedative combined with a rapid acting neuro-muscular blocker
– Commonly midazolam and suxamethonium
• Controversial
– Supporters claiming it was better than doing nothing at all
– Opponents claiming it was too dangerous in paramedic hands and that the risks were too high
RSI in paramedic hands
• Those services that introduced RSI in paramedic hands did so because
– Trauma bypass policies were increasing the time to definitive airway care in some patients
– RSI is the expected standard when the patient is in-hospital and so it should be the expected standard when the patient is pre-hospital
– There is nothing about RSI that demarcates it as a medical only intervention
– Given ideal intubating conditions (a sedated and paralysed patient) intubation success rates were reasonable (>95%) in experienced paramedic hands
– The potential risks of RSI were outweighed by the potential benefits to the patient
RSI – our experience
• We were one of the services that introduced RSI
– Selected (this was controversial) advanced paramedics
• One on one tuition and training with their medical advisor
• One on one de-briefing of all RSIs and potential RSIs
– They have to email and phone me afterward
• Criteria
– GCS less than ten
– Compromised airway
– More than fifteen minutes from hospital
– Note – not restricted to patients with TBI
• We use midazolam, suxamethonium and vecuronium
RSI – our procedure
• RSI procedure
– Pre-oxygenate
– Monitoring – pulseoximetry, waveform capnography, ECG, NIBP
– Midazolam (0-5 mg) and suxamethonium (100-150mg)
– Note – we do not use cricoid pressure but we do liberally use anterior tracheal pressure (modified BURP)
– Confirm ETT placement with capnography
– Ventilate to end tidal CO2 of 35-40 mmHg
– Vecuronium to keep the patient still
– Morphine and midazolam titrated to maintain sedation if required
– Failed intubation drill if unable to intubate
Our failed Intubation Drill
RSI – our experience so far
• We have performed just over 280 RSIs
– 96% success rate
– All failed intubations managed without cricothyroidotomy
– Still early days
• We are averaging just over one RSI per week
– 75% trauma
• We have a median of around 3 RSIs per year per officer
– I am not sure this number is high enough
• It has been very hard choosing who gets it and who doesn’t
– This has created some controversy in our service
Everyone wanted to be part of it
RSI – what we have learnt
• We have learnt some things
– Decision making skills are more important than intubation skills
– The subtleties of the procedure are very important
– It is much smoother with two advanced paramedics present
– One on one debrief is important (including potential RSIs)
– It is very easy to hyperventilate patients (even with capnography)
– It adds 10-15 minutes scene time
– It calms everyone down (including hospital staff)
– It has provided incentive to some who thought careers had peaked
• Things I remain uncertain of
– How many they need to do per year to maintain competency
– How to maintain the balance between maximising the number of paramedics who have the skill and maximising individual exposure
– Whether or not it actually helps the patient
But does it help the patient?
• The results of trials looking at interventions to reduce secondary injury have been universally disappointing
– Intubation
– Hypertonic saline fluid resuscitation
• There have many other interventions that we thought were beneficial that have turned out to be harmful when an appropriately powered trial was done
• A study published in 2003 caused supporters of RSI in paramedic hands to take a deep breath…
– Davis DP, Hoyt DB, Ochs M, et al. The effect of paramedic rapid sequence intubation on outcome in patients with severe traumatic brain injury. J Trauma, 2003, 54:444-53
– The San Diego RSI trial
The San Diego RSI trial
• A comparison of patient outcome data before and after RSI introduced
• 2 years after RSI introduced
– 209 patients intubated with RSI
– Very similar indications and procedure to our own
– Compared with 627 matched patients who had not been intubated prior to introduction of RSI
• Findings
– Mortality rose : 41.1% vs 30.3% (p<0.05)
– Good outcomes fell : 45.5% vs 57.9% (p<0.01)
• Publication resulted in heated discussion
– Opponents of RSI in paramedic hands calling for it to be withdrawn
The San Diego RSI trial
• The reasons for the rise in mortality and morbidity were unclear
– There was a lot of desaturation during laryngoscopy
– There was a lot of hyperventilation post intubation (this is extremely bad for the injured brain)
– There was a large number of paramedics performing a small number of RSIs and individual exposure was very low
– There was a high failed intubation rate (around 15%)
• Take home message: RSI done badly is worse than basic airway done well
RSI done badly is worse than basic airway care done well
• We looked at all of the issues
– We thought our own circumstances were quite different from San Diego
– We chose not to withdraw RSI in
paramedic hands
– We have to admit though, that we might
be doing harm without knowing it
– It is definitely time for a randomised trial
• Two interesting trials underway
– Victorian RSI trial
• I have some concerns with trial design
– New South Wales HIRT trial
• I have some concerns with trial design
In conclusion
• Despite our pre-conceived ideas, existing evidence does not support either intubation or RSI as good things to do
• This is very disturbing…
• The evidence does not support patients with TBI being intubated pre-hospital by paramedics
– Impossible to stop these patients being intubated (if it is easy to do), unless you take the skill away
– If it were a new skill being considered today we would not introduce it on the basis of the existing evidence
• Intubation using sedative drugs to overcome airway reflexes is dangerous and should be banned (some services still allow this)
In conclusion
• The limited evidence does not support RSI pre-hospital in paramedic hands
– The level of evidence is poor
• I think it is possible that RSI in paramedic hands is safe and feasible in selected, tightly controlled circumstances
– I don’t think it is safe and feasible in all paramedic hands
– It is a lot of work to ensure it is done well
– This means that it may not be feasible in the real world
• I cannot be completely confident it is safe
– I have to admit that it might not be
– If the Melbourne randomised trial shows RSI in paramedic hands makes outcomes worse, we will withdraw RSI
Questions?
|
Ministry
of Health
