Abstract
Objective: To test the efficacy and ease of use of
an oxygen-powered resuscitator/inhalator to provide ventilatory
support in the prehospital setting. The bag valve device is
the current standard of care. This study uses the hypothesis
that the Oxylator is as effective as this current standard.
Method: We conducted a prospective randomized clinical
trial of the prehospital population requiring airway management.
We used a hospital-based paramedic service providing 911 emergency
care in an urban setting. All paramedics received 3 hours of
training prior to use of the device.
Results: Twenty-one patients were entered into the
study group and thirteen into the control group. Initial pulse
oximeter readings Initial
pulse oximeter readings in the study group ranged from 59%
to 99% with a mean of 86%. The highest oximeter reading ranged
from 84-100% with a mean of 98%. In the control group initial
pulse oximeter readings ranged from 64-95% with a mean of
84%. The highest readings were from 84-100% with a mean of
96%. This was not statistically significant.
in the study group ranged from 59% to 99% with a mean of 86%.
The highest oximeter reading ranged from 84-100% with a mean
of 98%. In the control group initial pulse
oximeter readings
Initial pulse
oximeter readings in the study group ranged from 59% to 99%
with a mean of 86%. The highest oximeter reading ranged from
84-100% with a mean of 98%. In the control group initial pulse oximeter readings ranged from 64-95% with a mean of 84%.
The highest readings were from 84-100% with a mean of 96%. This
was not statistically significant.
ranged from 64-95% with a mean of 84%. The highest readings
were from 84-100% with a mean of 96%. This was not statistically
significant. Using a numerical
scale of 1-5 to determine ease of use, cleaning and assembly
of the OxylatorUsing a numerical scale of 1-5 to determine ease of use, cleaning and assembly of the Oxylator, "very easy", was reported in
71.4%, 76.2%, and 80.9% respectively.
, "very easy", was reported in 71.4%, 76.2%, and 80.9%
respectively.
Conclusion: The Oxylator® EM-100 was found to be
a useful tool in the prehospital setting. No adverse outcomes
were described and pulse oximeter readings similar to those
obtained using conventional methods were recorded. Paramedics
and patients made favorable comments regarding its use. Further
studies will be needed but the Oxylator® EM-100 may prove
to be very useful in the prehospital.
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Introduction
The current standard of care for providing ventilatory support
in the pre-hospital setting is the bag valve. The purpose of
this study is to compare the efficacy of the Oxylator® EM-100
(CPR Medical Devices Inc Ontario, Canada) as an alternative
to this current standard. This device is used in place of the
bag- valve in conjunction with either a facial mask or an endotracheal
tube. The Oxylator is an oxygen-powered resuscitator/inhalator
and requires an oxygen source of 40 liters/minute at 50 psi
to function.
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Method
A prospective randomized trail was conducted in the prehospital
setting by hospital based paramedics providing 911 emergency
care in an urban environment. The population studied included
adults (>18 years age) requiring airway management whose
needs would normally be met by use of a bag-valve mask or bag-valve
endotracheal intubation.
The following exclusion criteria were used:
| • |
Children less than 18 years |
| • |
Asthmatics with active bronchospasm |
| • |
Patients in full cardiac arrest
(apneic and pulseless) |
The study protocol was submitted to and met with IRB (Institutional
Review Board) approval prior to its initiation.
All paramedics involved in the study attended a mandatory three-hour
training session consisting of both a didactic lecture and hands
on teaching prior to use of the device. During this training,
the data collection sheet was reviewed and all participants
were familiarized with the consent form for patients enrolled
in the study.
The device, for purposes of the study, was only used during
patient transport, which was defined as the time the patient
spent in the ambulance itself. Randomization was based on the
day of the week, starting at 00.01 of the day in question. The
Oxylator (study group) was enrolled on Monday, Wednesday, Friday
and Sunday and control (bag valve) patients were entered on
the alternate days. Verbal consent was obtained from either
the patient or a relative by reading from a prepared handout
and a copy of this was then given to them.
All participants were encouraged to contact the study physicians
if they had any questions concerning the study and their involvement.
Patients were freely allowed to refuse to participate and in
such cases the bag- valve mask was used. Patient treatment was
not delayed or altered in any way while consent was obtained.
On arrival in the ambulance, an initial pulse oximeter reading
was obtained using Model 340-pulse oximeter (Palco Laboratories).
On study days the Oxylator was the used in conjunction with
either a facial mask or an endotracheal tube depending on the
patients airway requirement. Should intubation of the patient
be required, use of the Oxylator was discontinued until the
airway was secured and the study then recommenced.
At all times a bag-valve mask was kept by the patient’s
side and was to be used at the paramedics discretion should
they encounter any problems with utilizing the Oxylator for
ventilatory support or should the patients pulse oximeter reading
fall below 90% saturation or 5% from baseline. Pulse oximeter
readings were then recorded at 3-minute intervals. Initial Oxylator
ventilation was carried out in manual mode with a peak pressure
of 25 cmH2O or 35 cmH2O for intubated patients. The peak pressure
is then adjusted to allow an inspiratory time of 2 seconds.
If this is not reached at a maximum pressure of 50-cm H2 O,
use of the Oxylator is abandoned. Once an inspiratory phase
of 2 seconds is reached the Oxylator may be switched to automatic
mode.
At all times attention is directed to maintaining an open airway
and to providing adequate ventilation. Monitoring of the patient's
status will continue as per paramedic protocol.
On completion of patient interaction, the paramedic completes
a data collection sheet indicating patients name, age, gender,
indication for ventilatory support, pulse oximeter readings,
Oxylator pressures, transport time and completes an numerical
scale to objectively describe the ease of use, ease of cleaning
and ease of assembly of the device.
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Results
Twenty-one patients were enrolled in the study group. These
were patients whose ventilatory requirements would normally
have been met by use of the bag valve. 66% of this group were
male and 34% female with a mean age of 58.4 years.
The control group consisted of thirteen patients and 61.5% were
male and 38.4% female. The mean age for this group was 67.3
years.
The indications for use of the Oxylator® EM-100 were varied.
Three patients (14%) required ventilatory assistance following
drug ingestion, six (28.5%) were suffering from pulmonary edema,
nine (42.8%) had unspecified respiratory failure, one (4.7%)
had a seizure disorder, and one (4.7%) had respiratory depression
due to carbon monoxide exposure.
Thirteen (61.9%) patients were intubated, 4 (19%) had been previousely
trached, and 4 (19%) patients used the Oxylator® EM-100
in conjunction with a facial mask.
In the control group 2 (15.3%) patients were determined to have
pulmonary edema, 6 (46%) had non-specific respiratory failure,
1 (7%) patient was comatose, and 1 (7%) had stridor following
and atttempt to hang himself.
Nine (69%) of the patients were intubated and 4 (30.7%) required
use of a facial mask.
Mode of use: In 15 patients (71.4%) the oxylator was
used in automatic mode with 2-4 cmH2O and in no case
was use of the device discontinued for mechanical or personnel
reasons.
Pulse
oximeter readings:
In the study group the initial pulse
oximeter mean reading was 82% with a range of 59-99%. The highest
mean reading was 95% with a range of 84-100% and the lowest
level mean reading was 81.4% with a range of 59-94%. The control groups initial pulse oximeter reading was 81.6%
with a range of 64-93%. The highest pulse oximeter reading mean
was 92.9% with a range of 84-100% and the lowest mean was 79.5%
with a range of 60-90%.
In the study group the initial pulse oximeter mean reading was
82% with a range of 59-99%. The highest mean reading was 95%
with a range of 84-100% and the lowest level mean reading was
81.4% with a range of 59-94%. For
a plot of pulse oximeter readings, click here.
In
the study group the initial pulse oximeter mean reading was
82% with a range of 59-99%. The highest mean reading was 95%
with a range of 84-100% and the lowest level mean reading
was 81.4% with a range of 59-94%. The control groups initial
pulse oximeter reading was 81.6% with a range of 64-93%. The
highest pulse oximeter reading mean was 92.9% with a range
of 84-100% and the lowest mean was 79.5% with a range of 60-90%.
The control groups initial pulse oximeter reading was 81.6%
with a range of 64-93%. The highest pulse oximeter reading mean
was 92.9% with a range of 84-100% and the lowest mean was 79.5%
with a range of 60-90%.
Ease
of use, cleaning, and assembly:
Using a numerical scale
of 1-5 to determine ease of use, cleaning and assembly of the
Oxylator, "very easy", was reported in 71.4%, 76.2%,
and 80.9% respectively.
Using a numerical scale of 1-5 to determine ease of use, cleaning
and assembly of the Oxylator, "very easy", was reported
in 71.4%, 76.2%, and 80.9% respectively. For
a bar graph of the ease of use, cleaning, and assembly of the
Oxylator® EM-100, click here.
Using
a numerical scale of 1-5 to determine ease of use, cleaning
and assembly of the Oxylator, "very easy", was reported
in 71.4%, 76.2%, and 80.9% respectively.
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Discussion
The Oxylator® EM-100 is a hand held oxygen powered resuscitator,
which meets American Heart Association (AHA), ASTM, and ISO
standards for ventilatory/resuscitation devices and has FDA
approval. The AHA recommends the following parameters for adult
ventilation in order to lessen the risk of gastric insufflation,
a frequency of 10-12 breaths/ minute, tidal volume of 0.8-1.2
liters/minute, inspiratory time of 1.5-2 seconds and inspiratory
flow of 30-40 liters/minute. These parameters have been met
by the Oxylator in both bench and live field-testing. Adjustable
pressure limits from 25-50 cmH2O may be set to allow
an inspiratory phase of 2 seconds to be achieved during use
of the device. In automatic mode the Oxylator has a baseline
PEEP of 2-4 cmH2O. In patients who have some respiratory
effort the Oxylator may be used in inhalation mode allowing
pressurized oxygen to be mixed with ambient air.
This study shows the device to be as efficient as the current
standard of care and it offers several safety features over
the bag valve.
| • |
The sensing chamber on the inspiratory
cycle may not be triggered until passive exhalation has
occurred, preventing the occurrence of stacked breaths. |
| • |
The orifice-controlled input reduces
the incoming gas flow to 40 liters/minute lessening the
risk of gastric insufflation. |
| • |
An anti-asphyxia device allows the
patient to breathe ambient air if the gas supply is exhausted. |
| • |
The device will not function and
a visual and auditory alarm will sound if airway patency
is not established. |
During use of the bag-valve mask the flow rate is not controlled
consistently, the airway pressure maybe difficult to control,
and there may be a tendency to hyperventilate which may lead
to gastric insufflation. There is no built-in alarm to warn
the user that airway patency has been lost and it requires the
user to watch for adequate chest excursions with inflation.
The Oxylator is not a portable ventilator but its use will free
up one hand, which may then be used to ensure a superior air
seal with a facial mask or do another task when an endotracheal
tube is used.
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Conclusion
Although the number of patients enrolled in this study are small,
the results are encouraging that the Oxylator® EM-100 is
at least as effective as a bag-valve mask device in providing
ventilatory support in the prehospital setting. In addition,
it has a number of inherent safety features, which may prove
to be very useful for first responders or basic EMTs (Emergency
Care Technicians) who provide initial basic airway management
in the field.
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