Laryxmask Supreme * or endotracheal tube in adults with cardiac arrest in prehospital care: a Randmised Controlled Trial

Airwaymanagement and ventilation are regarded as a fundamental and essential
component in the care for the critically ill patient or trauma victims in
prehospital care. National and international guidelines from the Dutch
Reanimation Council and the European Resuscitation Council describe
endotracheaal intubation (ETI) as a primary condition for a safe airway and
optimal oxygenation and ventilation. In these guidelines endotracheaal
intubation (ETI) is considered as the *golden standard* for an adequate
airwaymanagement and ventilation for the ambulance care in the Netherlands.
Prehospital resuscitation often takes place under far from ideal conditions.
There is frequently talk of uncontrolled, stressful and sometimes chaotic
conditions that put pressure on the advantages of ETI. Victims are in positions
where they are difficult to access or have injuries of the face and are rarely
fasted. Factors that asks a great deal in expertise of the paramedic in bag
valve ventilation and intubation skills.
Several international publications in recent years show that ambulance
proffessionals may not reach the level that is required to perform an adequate
support of airway and ventilation. The low success rates of pre-hospital care
providers indicate inadequate initial training and achieve inadequate recurrent
training. To keep these skills at the desired level at least 12 intubations per
annum are required while in our organization an average of 5 per annum is
reached. The cost to keep the employees at the desired level is very high;
minimal one day of training per annum. Complications with endotracheaal
intubations by paramedics are reported in the literature are mostly on
unrecognized oesophageal intubations, too high cuff pressures, unrecognized
main stem bronchial intubation and prolonged and multiple attempts.
The main message that emerges from international publications is a growing
burden of proof is described that ETI by paramedics is not the ideal method for
airwaymanagement and even may be detrimental to the outcome of the patient. In
the Dutch ambulance care there are - still - no studies being done on efficacy
and safety of ETI.
The alternative to ETI in the prehospital seems to present itself with
supraglottic airway devices (SAD). In the clinical setting SAD*s have shown
their value as reliable, safe and effective device for some time.
Internationally, there is an increasing use of SAD's as an alternative to
endotracheaal intubation in prehospital airwaymanagement. Research shows that
placing a SAD by prehospital care providers has a much shorter learning curve
and less training is necessary to maintain it. This allows the current training
costs at least be halved.
The difference between supraglotic or endotracheaal airway management is the
position of the tube and cuff. With proper endotracheaal intubation, the
trachea is closed just below the vocal cords and the tip of the tube is just
above the carina so that both lungs are ventilated. In supraglottic airway
devices, the laryngopharynx is closed by a balloon with an opening to the
larynx (laryngeal mask) or in combination with closure of the esophagus
(Combitube / laryngeal tube).

The LMA is since 1990 clinically a widely accepted and respected airway device
that is easy to make and very patient-friendly (less reflexes / tightness
glottis). Because this is applicable in fasted patients, it was not outside the
clinic. With the advent of the LMA Supreme* it is possible to place a stomach
tube via an additional opening in order to improve the chances of regurgitation
leveling.

The purpose of this study is to demonstrate the added value of usingLMA
Supreme* in the ambulance care in the Netherlands with CPR indigent patients.
The hypothesis is that the value of using theLMA Supreme* is to be found in the
safety and speed of placing the device and the positive learning curve for the
paramedic.

The study is a randomized comparative trial (RCT = randomized controlled trial)
between two methods to create a safe airway and effective ventilation for
patients with a cardiac arrest.
In the region of North and East Gelderland all resuscitations in adults will be
performed using ETI or LMA Supreme* for a period of 5 months (starting
mid-February 2011). The number of patients to be included is 200 (100-100). The
power calculation can be adjusted if the outcome of the pilot study clearly
shows differences compared to other clinical trials.
Due to practical constraints we have decided not to collect data by an
independent researcher during resuscitations but use objective data. This will
be collected through the registration of vital signs (monitor Life Pack 12 and
Corpuls) and a measure method what will make it possible to read the
intubation time and number of attempts from a printed strip. To avoid
disturbing the process of acute care we choose to have the ambulance nurse fill
in an evaluation form (subjective data). If the patient is transferred to the
clinic the receiving physician will also be asked to fill in an evaluation
form.

Randomization
In all ambulance vehicles the emergency cases will be equipped with both
devices. Randomization using numbered envelopes will be done beforehand to
decide which device will be placed. A total of 200 envelopes will be
distributed on the vehicles inside the region North-East Gelderland. All
relevant forms are also placed in this case. If it not possible to create a
safe airway and effective airway management with the pre-identified aiway
device than it is possible to use a alternative method (bailout).

The method
For this study, the paramedic are asked to make a printout of the monitor
(LP12) of cardiac resuscitations complemented by a registration form with trip
number, employee number, patient data, ROSC yes or no and destination of the
hospital. To determine the intubation time it is necessary that the LP12 and
Corpuls Monitor will be updated with a configuration of the curve endtidal-CO2
in combination with paddles. The paramedics will be asked to start end tidal -
CO2 record mode when ventilating by bagvalvemask (by placing capnometers
between filter and ambu balloon and activate the printer to the monitor). After
correct placement of airway device (to be checked by auscultation and
registration CO2), the printer can be stopped. The installation time of the
device can now be read as well as the number of attempts. To change these
working methods correctly it is necessary to carry out instructions to the
paramedics during work meetings and regular training days.
Immediately after resuscitation, the ambulance nurse is asked to fill out a
brief questionnaire to record their experience and subjective data.
The patient*s data (name / birth date) are necessary to link the data from the
digital ambulance form. The staff number is needed to question the paramedic
for any gaps or ambiguities. To obtain a complete overview of all
resuscitations in the study area the data from the digital patient
documentation system will be requested from the quality administrator.
The procedure during the two phases (pilot / RTC) is according to the National
Ambulance Protocol 7.1 except the following points:
a. Prior to placing the device the AVP will give 2 breaths with the bag
valvemask.
b. Registration of CO2 will take place as soon as the AVP is ready to insert
the airway device until the device is placed in the right position (this is
controlled by auscultation the stomachdimple and 4 lung fields and CO2
detection).
c. In half of the research group a LMA Supreme* will be placed
d. If more than three attempts are needed a bailout will be placed (EIT or LMA
Supreme* / alternative: bag valvemask)
e. After placing the airway device thorax compressions - ventilations will be
continued (simultaneously)
These points are mentioned in the guidelines 2011 of the American Heart
Association (AHA) and the European Resuscitation Council (ERC).

Direct therapeutic effects and risks:
Benefit:
By using an airway device which can be easily placed within the LMA Supreme*
group, the expectation is that there will be a beneficial effect on the
resuscitation procedure. By positioning directly above the larynx complications
such as bleeding or damage are less likely to be expected.
Risks:
The risk of aspiration during the resuscitation procedure, both at ETI asLMA
Supreme*, will be reduced by the placement of a nasogastric tube.
By making both techniques available as a bailout patient*s safety will improve
above the current procedure (only bag valvemask as an alternative). The review
organization will be asked for dispensation of ensuring subjects as required
according by the WMO.