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Background: CPAP is frequently used in prehospital and emergency settings. An air-flow output minimum of 60 L/min and a constant positive pressure are 2 important features for a successful CPAP device. Unlike hospital CPAP devices, which require electricity, CPAP devices for ambulance use need only an oxygen source to function. The aim of the study was to evaluate and compare on a bench model the performance of 3 orofacial mask devices (Ventumask, EasyVent, and Boussignac CPAP system) and 2 helmets (Ventukit and EVE Coulisse) used to apply CPAP in the prehospital setting. Methods: A static test evaluated air-flow output, positive pressure applied, and FIO2 delivered by each device. A dynamic test assessed airway pressure stability during simulated ventilation. Efficiency of devices was compared based on oxygen flow needed to generate a minimum air flow of 60 L/min at each CPAP setting. Results: The EasyVent and EVE Coulisse devices delivered significantly higher mean air-flow outputs compared with the Ventumask and Ventukit under all CPAP conditions tested. The Boussignac CPAP system never reached an air-flow output of 60 L/min. The EasyVent had significantly lower pressure excursion than the Ventumask at all CPAP levels, and the EVE Coulisse had lower pressure excursion than the Ventukit at 5, 15, and 20 cm H2O, whereas at 10 cm H2O, no significant difference was observed between the 2 devices. Estimated oxygen consumption was lower for the EasyVent and EVE Coulisse compared with the Ventumask and Ventukit. Conclusions: Air-flow output, pressure applied, FIO2 delivered, device oxygen consumption, and ability to maintain air flow at 60 L/min differed significantly among the CPAP devices tested. Only the EasyVent and EVE Coulisse achieved the required minimum level of air-flow output needed to ensure an effective therapy under all CPAP conditions.
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CPAP Devices for Emergency Prehospital Use: A Bench Study
Claudia Brusasco MD, Francesco Corradi MD PhD, Alessandra De Ferrari MD, Lorenzo Ball MD,
Robert M Kacmarek PhD RRT FAARC, and Paolo Pelosi MD
BACKGROUND: CPAP is frequently used in prehospital and emergency settings. An air-flow
output minimum of 60 L/min and a constant positive pressure are 2 important features for a
successful CPAP device. Unlike hospital CPAP devices, which require electricity, CPAP devices for
ambulance use need only an oxygen source to function. The aim of the study was to evaluate and
compare on a bench model the performance of 3 orofacial mask devices (Ventumask, EasyVent, and
Boussignac CPAP system) and 2 helmets (Ventukit and EVE Coulisse) used to apply CPAP in the
prehospital setting. METHODS: A static test evaluated air-flow output, positive pressure applied,
and F
IO
2
delivered by each device. A dynamic test assessed airway pressure stability during simu-
lated ventilation. Efficiency of devices was compared based on oxygen flow needed to generate a
minimum air flow of 60 L/min at each CPAP setting. RESULTS: The EasyVent and EVE Coulisse
devices delivered significantly higher mean air-flow outputs compared with the Ventumask and
Ventukit under all CPAP conditions tested. The Boussignac CPAP system never reached an air-flow
output of 60 L/min. The EasyVent had significantly lower pressure excursion than the Ventumask
at all CPAP levels, and the EVE Coulisse had lower pressure excursion than the Ventukit at 5, 15,
and 20 cm H
2
O, whereas at 10 cm H
2
O, no significant difference was observed between the 2
devices. Estimated oxygen consumption was lower for the EasyVent and EVE Coulisse compared
with the Ventumask and Ventukit. CONCLUSIONS: Air-flow output, pressure applied, F
IO
2
de-
livered, device oxygen consumption, and ability to maintain air flow at 60 L/min differed signifi-
cantly among the CPAP devices tested. Only the EasyVent and EVE Coulisse achieved the required
minimum level of air-flow output needed to ensure an effective therapy under all CPAP conditions.
Key words: noninvasive CPAP; emergency department; ambulance; cardiogenic pulmonary edema;
helmet CPAP; Boussignac; acute respiratory failure. [Respir Care 0;0(0):1–•. © 0 Daedalus Enterprises]
Introduction
Noninvasive ventilation (NIV) reduces the need for en-
dotracheal intubation, the occurrence of nosocomial infec-
tions, and both morbidity and mortality associated with
respiratory failure.
1-5
The benefits of NIV are greater if
started early, thus constituting the rationale for the increas-
ing use of NIV in prehospital and emergency department
settings.
6-8
Because of its ease of use and the small size of
commercially available devices, CPAP is the most com-
monly used NIV technique in these settings.
5,9
The bene-
fits of CPAP have been extensively described in the treat-
ment of acute cardiogenic pulmonary edema
10-12
and acute
Drs Brusasco, De Ferrari, Ball, and Pelosi are affiliated with the Dipar-
timento di Scienze Chirurgiche e Diagnostiche Integrate, Sezione Anes-
tesia e Rianimazione, Universita` degli Studi di Genova, Genova, Italy.
Drs De Ferrari, Ball, and Pelosi are also affiliated with the Istituto di
Ricovero e Cura a Carattere Scientifico (IRCCS) Azienda Ospedaliera
Universitaria San Martino-Istituto Scientifico Tumori, Genova, Italy. Dr
Corradi is affiliated with the SC Anestesia e Rianimazione, EO Os-
pedali Galliera, Genova, Italy. Dr Kacmarek is affiliated with the
Department of Anesthesiology and Critical Care and the Department
of Respiratory Care, Massachusetts General Hospital, Boston,
Massachusetts.
Dr Kacmarek has disclosed relationships with Covidien and Venner Med-
ical. The other authors has disclosed no conflicts of interest.
Correspondence: Claudia Brusasco MD, Dipartimento di Scienze Chiru-
rgiche e Diagnostiche Integrate, Sezione Anestesia e Rianimazione, Uni-
versita` degli Studi di Genova, Largo Rosanna Benzi 8, 16132 Genova,
Italy. E-mail: claudia.brusasco@gmail.com.
DOI: 10.4187/respcare.04134
RESPIRATORY CARE ●●VOL NO1
RESPIRATORY CARE Paper in Press. Published on September 29, 2015 as DOI: 10.4187/respcare.04134
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and proofread. However, this version may differ from the final published version in the online and print editions of RESPIRATORY CARE
respiratory failure
13-15
and include opening collapsed al-
veoli, preserving patency of already open-lung units, im-
proving gas exchange, reducing patient’s work of breath-
ing,
16
and increasing cardiac performance by a reduction
in venous return and left-ventricular afterload.
17-19
CPAP
can be delivered with masks or helmets.
For successful CPAP treatment, CPAP devices must
deliver sufficiently high air flow to maintain airway pres-
sure throughout the breathing cycle. Because conditions
such as tachypnea, high minute ventilation, or large tidal
volumes can increase inspiratory flows, air flow delivered
by CPAP devices should always be higher than the pa-
tient’s peak inspiratory flow to ensure positive airway pres-
sure during the entire breathing cycle. A minimum of 60
L/min is generally considered sufficient to guarantee a
constant CPAP level under most degrees of patient in-
spiratory demand,
20
although higher flows might be re-
quired in severe respiratory distress at high breathing
frequency, large tidal volumes, and high minute ventila-
tion.
20,21
Delivered F
IO
2
is dependent upon the amount of
air entrained during the operation of the device and the
patient’s inspiratory demand. If the device entrains a large
volume of room air, the maximum F
IO
2
will be limited. In
addition, the more that the patient’s inspiratory demand
exceeds the total air-flow output of the device, the lower
the F
IO
2
will be because additional room air must be en-
trained to meet the patient’s demand for inspiratory flow.
The aim of this study was to evaluate and compare the
intrinsic capabilities of 5 commercially available CPAP
devices in prehospital and emergency settings. The per-
formance of each device was evaluated in terms of effec-
tiveness (air-flow output, pressure, and F
IO
2
) and efficiency
(oxygen consumption by the device).
Methods
Devices
Five commercially available devices for delivery of non-
invasive CPAP in prehospital settings were studied (Fig.
1): 3 orofacial mask devices (Ventumask [StarMed, Mi-
randola, Italy], EasyVent [Dimar, Mirandola, Italy], and
Boussignac CPAP system [Vygon, E
´couen, France]) and 2
helmet-type devices (Ventukit [StarMed] and EVE Cou-
lisse [Dimar]). All of these devices require only an oxygen
source to generate CPAP, thus making them useful on
ambulances.
The Ventumask, EasyVent, Ventukit, and EVE Coulisse
devices use the Venturi effect to entrain room air and
generate a high gas output flow and an adjustable mechan-
ical CPAP valve to set the desired positive pressure. A
supplementary oxygen source located downstream from
the air-entrainment valve can be connected to increase
F
IO
2
. Tables provided by the manufacturers indicate, for
each level of CPAP, the oxygen flows needed to provide
a specific total air flow and F
IO
2
with a maximum use of 15
L/min oxygen.
The Boussignac CPAP system uses the virtual Boussig-
nac valve,consisting of a small cylinder with 4 micro-
channels: when receiving oxygen flow from a source, tur-
bulence is generated inside the cylinder itself, resulting in
a positive pressure. The performance of the Boussignac
CPAP system depends only on the delivered oxygen flow:
F
IO
2
and positive pressure cannot be set by the operator
because both are a result of the oxygen flow setting re-
quired to power the device and the amount of air the
patient inhales above that delivered by the device. This
device does not incorporate an air-entrainment Venturi
system.
The Ventukit and EVE Coulisse are 2 transparent, latex-
free, polyvinylchloride hoods joined by a metal ring to soft
polyvinylchloride collars to form helmets. These devices
have an internal gas volume of 17 L. Both helmets include
an air-entrainment system utilizing the Venturi effect and
an adjustable CPAP valve. The Ventukit helmet has a plug
to reduce the noise generated by the device at the exit
point of the flow generated by the air-entrainment Venturi
system exerting 6 cm H
2
O per 50 L/min resistance to gas
flow.
QUICK LOOK
Current knowledge
CPAP is frequently used in prehospital and emergency
settings. A minimum flow output of 60 L/min and a
constant positive pressure are 2 important features of a
successful CPAP device. CPAP devices for ambulances
typically need only an oxygen source to function. In-
spired oxygen can be altered by air entrainment, which
also increases total flow. Prehospital use of CPAP for
cardiogenic pulmonary edema is associated with im-
proved clinical outcomes.
What this paper contributes to our knowledge
In a bench study of 5 CPAP devices, there were con-
siderable differences in performance among the devices
tested. The EasyVent and EVE Coulisse achieved the
best overall performance in terms of effectiveness and
efficiency; the Ventumask and Ventukit presented more
limited air-flow outputs at lower positive pressures; and
the Boussignac CPAP system delivered low total air-
flow outputs, low positive pressures, and high non-
adjustable F
IO
2
. Clinicians and prehospital caregivers
should be aware of specific device performance char-
acteristics to optimize effective application of CPAP in
prehospital and emergency settings.
CPAP IN EMERGENCY SETTINGS
2RESPIRATORY CARE ●●VOL NO
RESPIRATORY CARE Paper in Press. Published on September 29, 2015 as DOI: 10.4187/respcare.04134
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Comparisons were performed between masks and be-
tween helmets because the devices from the same manu-
facturer (Ventumask/Ventukit and EasyVent/EVE Cou-
lisse) use the same air-entrainment system and the
difference between devices is the interfaces (mask or hel-
mets). Moreover, the choice to use a mask or a helmet is
strictly clinical, based on the patient’s adherence or ex-
pected duration of needed assistance.
Experimental Setting
Figure 2 shows the in vitro circuit used to evaluate the
performance of each device in terms of flow, generated
pressure, and delivered F
IO
2
. A flow meter (ICU-Lab,
KleisTEK, Bari, Italy) measuring air flow generated by the
CPAP device was positioned downstream from each CPAP
device’s air-entrainment valve, as well as a rapid-response
oxygen analyzer (MaxO
2
AE, Maxtec, Salt Lake City,
Utah) and a manometer.
The Ventumask, EasyVent, Ventukit, and EVE Coulisse
devices were evaluated without CPAP and at 4 levels of
CPAP (5, 10, 15, and 20 cm H
2
O) set with each device’s
adjustable valve. For each CPAP valve level, the devices
were tested at oxygen source flows of 5–15 L/min in 1
L/min increments, and generated pressure, air flow, and
F
IO
2
were measured. The Boussignac CPAP system was
evaluated for delivered air flow, F
IO
2
, and pressure starting
at 5 L/min oxygen up to 30 L/min, as recommended by the
manufacturer, in 1 L/min increments from 5 to 15 L/min
and then in 5 L/min steps to 30 L/min.
Each device was evaluated during simulated spontane-
ous breathing using a lung model. Airway pressure stabil-
ity throughout the breathing cycle, estimated by calculat-
ing the mean of the pressure excursion inside the device
chamber (maximum pressure-minimum
pressureexcursion pressure), was used as an indirect in-
dex of work of breathing. As shown in Figure 2, a pneu-
matic lung simulator (Dimar) generating a mildly tachy-
pneic sinusoidal flow pattern (tidal volume 500 mL,
inspiratory time 0.8 s, expiratory time 1.6 s, breathing
frequency 25 breaths/min) was directly connected to each
device. A pneumotachograph and pressure transducer (ICU-
Lab) were positioned between devices and the pneumatic
lung simulator, and each device was tested during 60 s of
uninterrupted simulated breathing. Air-entrainment devices
were evaluated by delivering increasing levels of oxygen
flow from 5 to 15 L/min in 1 L/min increments and then
from 15 to 30 L/min in 5 L/min increments and at 4
different CPAP levels (5, 10, 15, and 20 cm H
2
O), set with
each device’s adjustable CPAP valve. The Boussignac
CPAP system was tested by delivering an increasing flow
of oxygen from 5 to 30 L/min. For all devices, pressure
excursion was calculated as mean of the pressure excur-
sion over the 25 ventilatory cycles occurring during the
recording time.
In addition, device oxygen consumption or rather oxy-
gen inflow requirement was calculated from an oxygen
tank (volume of 7 L) fully charged at 200 bar for a total
1,400 L of oxygen. The oxygen flow needed to generate a
minimum air-flow output of 60 L/min was used to esti-
mate efficiency in total minutes of run time. All experi-
ments were carried out by the same researcher (CB).
Statistical Analysis
Data are expressed as mean SD. All statistical anal-
yses were performed using SPSS 21 (IBM, Armonk, New
York), and significance was considered to be P.05. All
data were analyzed by averaging measurements on 3 dif-
ferent devices of each evaluated model.
Gas Output Flow Generation Performances
The total gas output flow obtainable with the different
devices was compared by 2-way analysis of variance, with
input flow and device as factors. The relationship between
oxygen input flow and generated air-flow outputs of each
device was tested by linear regression analysis.
Fig. 1. The 5 tested devices. A: Boussignac CPAP system; B:
EasyVent; C: Ventumask; D: Ventukit; E: EVE Coulisse.
CPAP IN EMERGENCY SETTINGS
RESPIRATORY CARE ●●VOL NO3
RESPIRATORY CARE Paper in Press. Published on September 29, 2015 as DOI: 10.4187/respcare.04134
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and proofread. However, this version may differ from the final published version in the online and print editions of RESPIRATORY CARE
Static Test
Masks and helmets were analyzed separately. The gen-
erated flows and F
IO
2
of devices, at a fixed oxygen input
flow of 15 L/min, were compared by 2-way analysis of
variance, with CPAP level and device as factors. Differ-
ences between devices at a given CPAP level were tested
post hoc, and Pvalues of multiple comparisons were cor-
rected using the Bonferroni correction.
Dynamic Test
Masks and helmets were analyzed separately. Normality
of distributions was assessed by the D’Agostino-Pearson
omnibus test, and correlations were assessed by Pearson R
or Spearman’s rho, accordingly. Pressure excursions of
masks and helmets were compared by 2-way analysis of
variance, with CPAP level and device as factors. Differ-
ences between devices at a given CPAP level were tested
post hoc, and Pvalues of multiple comparisons were cor-
rected using the Bonferroni correction.
Results
Gas Output Flow Generation Performances
The gas output flow of each device without a CPAP
valve was linearly related to the oxygen input flow (Fig.
3), and the results of linear regression are reported in Table
1. The EasyVent (83 27 L/min) and EVE Coulisse
(78 28 L/min) produced a greater air-flow output than
the Ventumask (49 20 L/min), Boussignac CPAP sys-
tem (10 4 L/min), and Ventukit (45 10 L/min) at all
oxygen input flows (P.001 for comparisons between all
pairs of devices, except EasyVent vs EVE Coulisse at an
input flow of 14 L/min, P.99).
Fig. 2. Illustration of the in vitro circuit used to evaluate the performance of each device in terms of flow, generated pressure, and delivered
F
IO
2.
Fig. 3. Air-flow outputs generated by each device at different oxygen flows from 5 to 15 L/min in 1 L/min increments without any CPAP valve.
CPAP IN EMERGENCY SETTINGS
4RESPIRATORY CARE ●●VOL NO
RESPIRATORY CARE Paper in Press. Published on September 29, 2015 as DOI: 10.4187/respcare.04134
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and proofread. However, this version may differ from the final published version in the online and print editions of RESPIRATORY CARE
Static Test
Masks. Considering the architectural differences between
the Boussignac CPAP system and the other 4 devices (in
particular, the inability to preset a positive pressure and
F
IO
2
), an initial separate characterization was performed
(Fig. 4). The maximum positive pressure achieved with
the Boussignac CPAP system was 9 cm H
2
O at an oxygen
input flow of 30 L/min; therefore, no direct comparison
with other mask devices could be performed at CPAP
levels of 10, 15, and 20 cm H
2
O.
At a CPAP of 5 cm H
2
O, the EasyVent generated a
higher output flow than the Ventumask and Boussignac
(120, 75, and 15 L/min, respectively; P.001 for all
pairwise comparisons), with a lower F
IO
2
(31, 37, and 58%,
P.001 for all comparisons). At a CPAP of 10 cm H
2
O,
the EasyVent generated a higher output flow than the Ven-
tumask (118 vs 70 L/min, P.001), with a lower F
IO
2
(30% vs 40%, P.001). At a CPAP of 15 cm H
2
O, the
EasyVent generated a higher output flow than Ventumask
(100 vs 72 L/min, P.001), with a lower F
IO
2
(33% vs
42%, P.001). At a CPAP of 20 cm H
2
O, the EasyVent
generated a higher output flow than the Ventumask (90 vs
40 L/min, P.001), with a lower F
IO
2
(35% vs 55%, P
.001).
Helmets. At a CPAP of 5 cm H
2
O, the EVE Coulisse
generated a higher output flow than the Ventukit (120 vs
60 L/min, P.001), with a lower F
IO
2
(31% vs 41%, P
.001). At a CPAP of 10 cm H
2
O, the EVE Coulisse gen-
erated a higher output flow than the Ventukit (112 vs 46
L/min, P.001), with a lower F
IO
2
(30% vs 47%, P
.001). At a CPAP of 15 cm H
2
O, the EVE Coulisse gen-
erated a higher output flow than the Ventukit (95 vs 35
L/min, P.001), with a lower F
IO
2
(32% vs 54%, P
.001). At a CPAP of 20 cm H
2
O, the EVE Coulisse gen-
erated a higher output flow than the Ventukit (80 vs 20
L/min, P.001), with a lower F
IO
2
(34% vs 80%, P
.001).
A comparison of the overall efficiency of all devices
with the static test is illustrated in Figures 4 and 5. All
CPAP devices showed a reduction of air-flow output and
an increase in F
IO
2
as the CPAP level was increased.
Dynamic Test
Because the Boussignac CPAP system never reached a
minimum air-flow output of 60 L/min, it was considered
not to be comparable with the other devices and was not
included in the dynamic bench test. Normality assumption
for pressure excursion distribution was rejected for both
masks and helmets, with P.001. The dynamic bench
test showed a significant negative correlation between the
gas flow generated by the CPAP devices and the pressure
excursion inside the device for both masks (rho ⫽⫺0.86,
P.01) and helmets (rho ⫽⫺0.79, P.03). For both
air-entrainment masks and helmets, a steep decrease in
pressure excursion was observed when the delivered flow
reached the threshold of 60 L/min (Fig. 6). Absolute val-
ues of pressure excursion were lower in helmets due to
their high internal volume.
The EasyVent had significantly lower pressure excur-
sion than the Ventumask at all CPAP levels (P.001),
and the EVE Coulisse had lower pressure excursion than
the Ventukit at 5 cm H
2
O(P.001), 15 cm H
2
O(P
.02), and 20 cm H
2
O(P.001), whereas at 10 cm H
2
O,
no significant difference was observed between the 2 de-
vices (P.99). The results of the dynamic test are illus-
trated in Figure 7. The efficiency of devices in terms of
oxygen consumption needed to achieve the output flow
threshold of 60 L/min at a given CPAP level are reported
in Table 2.
Discussion
The major findings of this study are: (1) different de-
vices for noninvasive CPAP varied significantly in their
Table 1. Output Flow Generation Performance of Each Tested
Device
Device Slope (95% CI) Intercept (95% CI) r
2
Boussignac system 0.7–0.9 0.8–3.1 0.97
Ventumask 5.9–6.4 14.5 to 9.8 0.99
EasyVent 4.8–11.0 7.3–8.8 0.98
Ventukit 4.2–5.3 18.7 to 5.3 0.99
EVE Coulisse 7.9–9.0 11.8 to 0.5 0.99
Results of linear regression of output flow versus input flow are reported.
Fig. 4. Performances of the CPAP Boussignac system. The X axis
represents CPAP values. The left Y axis represents air-flow out-
puts, and the right Y axis represents F
IO
2generated at different
oxygen flows from 5 to 30 L/min. Point labels are input flows
(L/min). With the Boussignac CPAP system, output flows were
slightly lower than input flows, possibly due to oxygen leakage
through the virtual valve.
CPAP IN EMERGENCY SETTINGS
RESPIRATORY CARE ●●VOL NO5
RESPIRATORY CARE Paper in Press. Published on September 29, 2015 as DOI: 10.4187/respcare.04134
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ability to deliver high air flow and F
IO
2
and to minimize
pressure excursion. (2) The Boussignac CPAP system de-
livered lower total air flows and higher F
IO
2
than air-en-
trainment devices, with pressure and F
IO
2
not indepen-
dently adjustable. (3) Of the air-entrainment devices, the
EasyVent and EVE Coulisse were both more effective and
efficient than Ventumask and Ventukit.
In this study, 5 CPAP devices commercially available
for prehospital and emergency department use were eval-
uated: 3 facial masks and 2 helmets. All of these devices
are easily usable during ambulance transport because none
require electrical power, but only an oxygen source, mak-
ing them ideal devices for prehospital emergency settings.
Four of these devices use the jet air-entrainment principle
to entrain room air, increasing the total air flow delivered
to the patient, and adjustable CPAP valves to provide CPAP.
The Boussignac CPAP system does not entrain ambient
air: the virtual Boussignac valve is designed only to es-
tablish a positive pressure.
Over the past decade, the Boussignac CPAP system has
been used frequently in emergency settings because it is
extremely easy to apply and does not require presettings
by the operator other than oxygen flow, making it conve-
nient for use by paramedical personnel on ambulances.
22-24
We presume that the success of the Boussignac CPAP
system is a result of these characteristics and the fact that
it delivers a high F
IO
2
. However, it does not maintain suf-
ficient air flow to prevent entrainment of ambient air by
the patient, affecting both the effective positive pressure
applied and F
IO
2
delivered. The positive pressure gener-
ated by the virtual valve reached a maximum of 9 cm H
2
O
when driven by 30 L/min oxygen. Because the virtual
valve is in open communication with the external environ-
ment, the oxygen concentration is lowered by dilution by
ambient air inspiration, and a drop in airway pressure at
high minute ventilation has been observed.
25
Moreover,
with each breath, depending on the patient’s respiratory
pattern and strength, a negative pressure will be generated
during inspiration, and a reversal of flow through the vir-
tual valve will occur during expiration, thus altering the
positive pressure generated by the system and therefore
not establishing CPAP.
Of the mask-based devices, the EasyVent demonstrated
greater efficiency than the Ventumask at the same CPAP
and oxygen settings and generated greater air-flow outputs
and lower F
IO
2
. The EasyVent generated high air-flow out-
put even with a CPAP of 20 cm H
2
O, always remaining
60 L/min. Moreover, 6 L/min oxygen was sufficient to
generate an air-flow output of 60 L/min without CPAP but
maintained a very low F
IO
2
. The Ventumask generated
good air-flow outputs at a CPAP of 5–15 cm H
2
O, but
total air-flow output decreased to 25 L/min at a CPAP of
20 cm H
2
O, with a consequent increase in F
IO
2
(50%).
Moreover, 10 L/min oxygen was needed to generate a total
Fig. 5. Ventumask (A), Ventukit (B), EasyVent (C), and EVE Coulisse (D) air-flow outputs at different CPAP levels (5, 10, 15, and 20 cm H2O)
and an input flow of 15 L/min are shown, as well as F
IO
2.
CPAP IN EMERGENCY SETTINGS
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air-flow output of 60 L/min at zero CPAP. The differences
between these 2 devices in air-flow output may be due to
the technical construction of the 2 jet entrainment systems.
In fact, with the EasyVent, oxygen flow enters the system
in parallel with air flow entrained from the external envi-
ronment, generating laminar air flow, whereas with the
Ventumask, oxygen flow enters at an acute angle to the
ambient air flow and entrains less air, possibly due to
the generation of turbulence.
Of the helmet devices, the EasyVent and EVE Coulisse
were similar in effectiveness, and this result was expected
because they both incorporate the same jet entrainment
systems applied to 2 different interfaces (mask vs helmet).
The Ventukit incorporates the same jet entrainment system
as the Ventumask, but the total air-flow output differed
between these 2 devices. Inside the helmet at the air-flow
output point, the Ventukit includes a plug to reduce the
noise generated by the jet entrainment system. This plug
certainly reduces the noise inside the helmet, but adds a
resistance, measured by the authors as 6 cm H
2
O per 50
L/min, significantly reducing the effectiveness of air en-
trainment. Unfortunately, this reduction in air entrainment
limits the use of the Ventukit because the air-flow output
was 60 L/min only at a CPAP of 5 cm H
2
O, with an
oxygen consumption of 14 L/min. An air-flow output 60
L/min is important in helmets not only to reduce the pa-
tient’s work of breathing, as with masks, but also to avoid
CO
2
rebreathing.
26,27
The EVE Coulisse maintained a total
air-flow output well over 60 L/min with CPAP set from 5
to 20 cm H
2
O and consumed from only 8 L/min oxygen at
a CPAP of 5 cm H
2
O to 13 L/min oxygen at a CPAP of 20
cm H
2
O.
Our data also support the clinical relevance of an air-
flow threshold of 60 L/min, which is recommended in
CPAP guidelines.
20,21
We found increased pressure excur-
sion and negative pressure spikes during the inspiratory
phase whenever 60 L/min was not reached (see Fig. 6).
Comparisons between devices systematically showed sig-
nificantly larger pressure excursion for those devices that
did not reach the 60 L/min threshold. In helmets, low total
air flow also resulted in lower pressures during the inspira-
Fig. 6. Relation between pressure excursion and gas output flow in
air-entrainment devices. A steep decrease in the first was ob-
served above a threshold of 60 L/min.
Fig. 7. Pressure excursion (maximum pressure-minimum
pressureexcursion pressure) of Ventumask and Easy Vent (panel
A) and Ventukit and Eve Coulisse (panel B) during the dynamic
bench test. Input flow, pressure, obtained output flow, and F
IO
2are
reported. * Significantly lower than the other device compared at
the same pressure and input flow (P.001). The Boussignac
CPAP system was not included in this graph because its applied
CPAP cannot be adjusted, and it does entrain ambient air.
CPAP IN EMERGENCY SETTINGS
RESPIRATORY CARE ●●VOL NO7
RESPIRATORY CARE Paper in Press. Published on September 29, 2015 as DOI: 10.4187/respcare.04134
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and proofread. However, this version may differ from the final published version in the online and print editions of RESPIRATORY CARE
tory phase, although pressure remained positive because of
the buffering effect of the high internal capacitance of the
helmet. Nevertheless, a minimum air-flow output of 60
L/min when applying CPAP through helmets is necessary
to avoid the risk of CO
2
rebreathing due to a low washout
flow, in addition to minimizing work of breathing.
The effectiveness of CPAP via mask or helmet at iden-
tical air flow and pressure is comparable.
28
The choice of
device depends on other factors, such as operator experi-
ence, device availability, expected time of support, and
patient’s tolerance. Normally, the mask is more readily
available and easier to apply, thus making it suitable for
ambulance transport. In the emergency department or the
wards, however, the helmet allows greater patient comfort
and avoids risk of skin lesions. Despite these general con-
siderations, the use of helmets in prehospital settings is
feasible, efficient, and safe.
5,7
The efficiency of CPAP devices is an important topic
especially during prehospital use. In fact, in some coun-
tries, oxygen availability on ambulances is limited, and
transportation times can vary greatly. Furthermore, oxy-
gen sources in ambulances in some countries can generally
deliver only up to a maximum of 15 L/min. Therefore,
when higher oxygen flows are needed, as with the Bous-
signac CPAP system, it is necessary to use 2 tanks simul-
taneously to achieve a gas delivery of 30 L/min.
The use of prehospital CPAP has increased consider-
ably in recent years due to the growing evidence regarding
the importance of early treatment of pathologies such as
acute cardiogenic pulmonary edema
5,6
and acute hyper-
capnic respiratory failure.
6,9,29
However, the most recent
studies offer little agreement about the utility of CPAP in
improving a patient’s outcome.
30-32
This is, in our opinion,
due to the heterogeneity of the approaches used to provide
CPAP: many did not specify which CPAP device was
used,
9,33
or they used the Boussignac CPAP system.
23,24,34,35
In contrast, the studies using air-entrainment CPAP sys-
tems concluded that CPAP in prehospital setting is highly
effective.
8,36,37
Due to the variable performance highlighted
by this bench study, it is clear that results of clinical trials
may be at least partially dependent on the effectiveness of
the device used.
Our study has some limitations that need to be addressed.
First, the devices were tested only in an in vitro circuit. As
a result, we were able to accurately describe and compare
the effectiveness and efficiency of each device, but we
were not able to reproduce different clinical conditions.
Thus, our results cannot be directly extrapolated to the
clinical scenario, and larger studies on healthy volunteers
and subjects with various respiratory conditions are needed.
Second, the devices tested were all CPAP devices for am-
bulance and emergency settings and are commercially avail-
able in Europe. Some new CPAP devices with similar
characteristics have recently been developed in the United
States. Owing to the heterogeneity of our results obtained
with the devices tested in this study, it would be advisable
to test with similar methodology the new CPAP devices in
the United States but not yet available in Europe.
Conclusions
In summary, we found considerable differences in per-
formance among the 5 CPAP devices tested. The EasyVent
and EVE Coulisse achieved the best overall performance
in terms of effectiveness and efficiency; the Ventumask
and Ventukit presented more limited air-flow outputs at
lower positive pressures; and the Boussignac CPAP sys-
tem delivered low total air-flow outputs, low positive pres-
sures, and high non-adjustable F
IO
2
. Clinicians and prehos-
pital caregivers should be aware of specific device
performance characteristics to optimize effective applica-
tion of CPAP in prehospital and emergency settings.
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CPAP IN EMERGENCY SETTINGS
RESPIRATORY CARE ●●VOL NO9
RESPIRATORY CARE Paper in Press. Published on September 29, 2015 as DOI: 10.4187/respcare.04134
Copyright (C) 2015 Daedalus Enterprises ePub ahead of print papers have been peer-reviewed, accepted for publication, copy edited
and proofread. However, this version may differ from the final published version in the online and print editions of RESPIRATORY CARE
... This represents the practical lower limit of oxygen consumption since below this, treatment modalities tend to wean patients onto non-enriched CPAP (i.e., no supplementary oxygen is provided) (4). The overall flow rate of the enriched air supplied to the patient needs to exceed at least 20 L/min (to avoid hypercapnia and maintain a positive pressure during inspiration) (23) and in this treatment context is more typically expected to be 60 L/min (24). ...
... To inform the development process of the LeVe system, our target requirements were defined as delivery of CPAP at a mean pressure of 10 cm H 2 O (1,000 Pa). The flowrate required to maintain positive pressure is not set a priori, but determined to ensure that the pressure remains positive for all parts of the breathing cycle, nevertheless a typical guide value of 60 L/min provided an initial starting point for a suitable flow (24). Within this CPAP regime, the system should achieve a minimum 40% FiO 2 using an oxygen flow rate of 5 L/min (under normal conditions) supplied at the modest delivery pressures that can be achieved by oxygen concentrators (24); there is some variation across concentrator models, widely used oxygen concentrators such as the Phillips Everflow can be considered representative and have outlet pressures of ca. ...
... The flowrate required to maintain positive pressure is not set a priori, but determined to ensure that the pressure remains positive for all parts of the breathing cycle, nevertheless a typical guide value of 60 L/min provided an initial starting point for a suitable flow (24). Within this CPAP regime, the system should achieve a minimum 40% FiO 2 using an oxygen flow rate of 5 L/min (under normal conditions) supplied at the modest delivery pressures that can be achieved by oxygen concentrators (24); there is some variation across concentrator models, widely used oxygen concentrators such as the Phillips Everflow can be considered representative and have outlet pressures of ca. 38 kPa (387 cm H 2 O) (26). ...
Article
Full-text available
Background: The COVID-19 pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has placed a significant demand on healthcare providers (HCPs) to provide respiratory support for patients with moderate to severe symptoms. Continuous Positive Airway Pressure (CPAP) non-invasive ventilation can help patients with moderate symptoms to avoid the need for invasive ventilation in intensive care. However, existing CPAP systems can be complex (and thus expensive) or require high levels of oxygen, limiting their use in resource-stretched environments. Technical Development + Testing: The LeVe (“Light”) CPAP system was developed using principles of frugal innovation to produce a solution of low complexity and high resource efficiency. The LeVe system exploits the air flow dynamics of electric fan blowers which are inherently suited to delivery of positive pressure at appropriate flow rates for CPAP. Laboratory evaluation demonstrated that performance of the LeVe system was equivalent to other commercially available systems used to deliver CPAP, achieving a 10 cm H 2 O target pressure within 2.4% RMS error and 50–70% FiO 2 dependent with 10 L/min oxygen from a commercial concentrator. Pilot Evaluation: The LeVe CPAP system was tested to evaluate safety and acceptability in a group of ten healthy volunteers at Mengo Hospital in Kampala, Uganda. The study demonstrated that the system can be used safely without inducing hypoxia or hypercapnia and that its use was well-tolerated by users, with no adverse events reported. Conclusions: To provide respiratory support for the high patient numbers associated with the COVID-19 pandemic, healthcare providers require resource efficient solutions. We have shown that this can be achieved through frugal engineering of a CPAP ventilation system, in a system which is safe for use and well-tolerated in healthy volunteers. This approach may also benefit other respiratory conditions which often go unaddressed in Low and Middle Income Countries (LMICs) for want of context-appropriate technology designed for the limited oxygen resources available.
... To inform the development process of the LeVe system, our target requirements were defined as delivery of CPAP at a mean pressure of 10 cm H2O (1000 Pa). The flowrate required to maintain positive pressure is not set a priori, but determined to ensure the pressure remains positive for all parts of the breathing cycle, nevertheless a typical guide value of 60 L/min provided an initial starting point for a suitable flow [19]. Within this CPAP regime, the system should achieve a minimum 40% FiO2 using an oxygen flow rate of 5L/min (under standard conditions) and at modest delivery pressures [19]. ...
... The flowrate required to maintain positive pressure is not set a priori, but determined to ensure the pressure remains positive for all parts of the breathing cycle, nevertheless a typical guide value of 60 L/min provided an initial starting point for a suitable flow [19]. Within this CPAP regime, the system should achieve a minimum 40% FiO2 using an oxygen flow rate of 5L/min (under standard conditions) and at modest delivery pressures [19]. For context, widely used oxygen concentrators such as the Phillips Everflow have outlet pressures of ca. ...
Preprint
Full-text available
Background: The COVID-19 pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has placed a significant demand on healthcare providers (HCPs) to provide respiratory support for patients with moderate to severe symptoms. Continuous Positive Airway Pressure (CPAP) non-invasive ventilation can help patients with moderate symptoms to avoid the need for invasive ventilation in intensive care. However, existing CPAP systems can be complex (and thus expensive) or require high levels of oxygen, limiting their use in resource-stretched environments. Technical Development + Testing: The LeVe (Light) CPAP system was developed using principles of frugal innovation to produce a solution of low complexity and high resource efficiency. The LeVe system exploits the air flow dynamics of electric fan blowers which are inherently suited to delivery of positive pressure at appropriate flow rates for CPAP. Laboratory evaluation demonstrated that performance of the LeVe system was equivalent to other commercially available systems used to deliver CPAP. Pilot Evaluation: The LeVe CPAP system was tested to evaluate safety and acceptability in a group of ten healthy volunteers at Mengo Hospital in Kampala, Uganda. The study demonstrated that the system can be used safely without inducing hypoxia or hypercapnia and that its use was well tolerated by users, with no adverse events reported. Conclusions: CPAP ventilation systems provide an important treatment option for COVID-19 patients. To deliver this for the high patient numbers associated with the COVID-19 pandemic, healthcare providers require resource efficient solutions. We have shown that this can be achieved through frugal engineering of a CPAP ventilation system, in a system which is safe for use and well tolerated in healthy volunteers. This approach may also benefit other respiratory conditions which often go unaddressed in LMICs for want of context-appropriate technology.
... Last, the helmet with an integral Venturi flow driver (the VentuKit) used in this study delivers a flow under the reported experimental conditions. It delivers a flow of approximately 48 L/min, which is not enough to perform a CPAP "high flow" device [42]. Studies [43,44] have shown that the esophageal pressure delta is lower when the device is able to deliver a higher flow and consequently a more stable airway pressure. ...
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Rationale and objective Various forms of Non-invasive respiratory support (NRS) have been used during COVID-19, to treat Hypoxemic Acute Respiratory Failure (HARF), but it has been suggested that the occurrence of strenuous inspiratory efforts may cause Self Induced Lung Injury(P-SILI). The aim of this investigation was to record esophageal pressure, when starting NRS application, so as to better understand the potential risk of the patients in terms of P-SILI and ventilator induced lung injury (VILI). Methods and measurements 21 patients with early de-novo respiratory failure due to COVID-19, underwent three 30 min trials applied in random order: high-flow nasal cannula (HFNC), continuous positive airway pressure (CPAP), and non-invasive ventilation (NIV). After each trial, standard oxygen therapy was reinstituted using a Venturi mask (VM). 15 patients accepted a nasogastric tube placement. Esophageal Pressure (ΔPes) and dynamic transpulmonary driving pressure (ΔPLDyn), together with the breathing pattern using a bioelectrical impedance monitor were recorded. Arterial blood gases were collected in all patients. Main results No statistically significant differences in breathing pattern and PaCO2 were found. PaO2/FiO2 ratio improved significantly during NIV and CPAP vs VM. NIV was the only NRS to reduce significantly ΔPes vs. VM (-10,2 ±5 cmH20 vs -3,9 ±3,4). No differences were found in ΔPLDyn between NRS (10,2±5; 9,9±3,8; 7,6±4,3; 8,8±3,6 during VM, HFNC, CPAP and NIV respectively). Minute ventilation (Ve) was directly dependent on the patient's inspiratory effort, irrespective of the NRS applied. 14% of patients were intubated, none of them showing a reduction in ΔPes during NRS. Conclusions In the early phase of HARF due to COVID-19, the inspiratory effort may not be markedly elevated and the application of NIV and CPAP ameliorates oxygenation vs VM. NIV was superior in reducing ΔPes, maintaining ΔPLDyn within a range of potential safety.
... An alternative configuration involves the connection of the helmet with a mechanical ventilator to provide noninvasive positive pressure ventilation, typically with the pressure support mode (NPPV) by either a single port (B) connected to the circuit Y piece (condition associated with a higher risk of CO 2 rebreathing, see text) or two separate ports (C) pressure by passing through the expiratory valve and preventing CO 2 rebreathing. In regard to the first aspect, it is worth noting that H-CPAP requires lower fresh gas flows (in the range of 60 l/min) than face masks (flows up to 100 or 120 l/min) [6]. With a helmet, the airway pressure is also stable if the patient's peak inspiratory flow exceeds the fresh gas flow because of its high compliance (i.e. ...
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A helmet, comprising a transparent hood and a soft collar, surrounding the patient’s head can be used to deliver noninvasive ventilatory support, both as continuous positive airway pressure and noninvasive positive pressure ventilation (NPPV), the latter providing active support for inspiration. In this review, we summarize the technical aspects relevant to this device, particularly how to prevent CO 2 rebreathing and improve patient–ventilator synchrony during NPPV. Clinical studies describe the application of helmets in cardiogenic pulmonary oedema, pneumonia, COVID-19, postextubation and immune suppression. A section is dedicated to paediatric use. In summary, helmet therapy can be used safely and effectively to provide NIV during hypoxemic respiratory failure, improving oxygenation and possibly leading to better patient-centred outcomes than other interfaces.
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The aim of this article is to describe the importance of a multidisciplinary team dedicated to noninvasive ventilation training of the emergency department's staff. In our experience, the presence of a medical and nursing “noninvasive ventilation group” made it possible to quickly teach expertise on the management of noninvasive ventilation of COVID-19 patients among emergency department doctors and nurses. This allowed improving a standardized approach regarding the identification and ventilatory assistance of patients with SARS-CoV-2 pneumonia needing ventilatory support, the correct use of the devices, and quick identification and reduction of the complications associated with noninvasive ventilation. In this article, we would like to encourage the formation of similar working groups in all situations where this is not yet present.
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Venturi-based flow generators are commonly used for noninvasive continuous positive airway pressure (CPAP) of high-flow nasal oxygen (HFNO). The system is simple and allows to increase the total flow while decreasing the FiO2 starting from a single oxygen source. In this report we describe the characteristics and performance of a novel Venturi system (EasyVEE, Levate, BG, Italy), which allows to vary the size of the port through which ambient air is entrained, hence allowing a continuous modulation of FiO2. The system allowed to modify FiO2 continuously between 35% and 80% and, consequently, a 1.5- to 4.5-fold increase of the total flow rate. A minimal decrease in entrainment performance was observed for positive end-expiratory pressure levels above 12.5 cmH2O. EasyVEE system appears to be a simple, flexible, and reliable solution to generate continuous flow for noninvasive respiratory support interfaces.
Chapter
During the COVID-19 pandemic, helmet non-invasive ventilation was proposed to provide respiratory support for patients with the promise of reducing the need for invasive mechanical ventilation. Other potential advantages of the helmet interface include better patient tolerability and decreased risk of aerosolization. However, limited data are currently available to guide its clinical use. The objective of this article is to review the current evidence on helmet non-invasive ventilation, including the pathophysiological rationale, and clinical data from acute hypoxemic respiratory failure in general, and from COVID-19 in particular.
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Abstract Background. Previous studies have demonstrated decreased rates of intubation and mortality with prehospital use of continuous positive airway pressure (CPAP). We sought to validate these findings in a larger observational study. Methods. We conducted a before and after observational study of consecutive patients transported by emergency medical services (EMS) during the 12 months before and the 12 months following implementation of a prehospital CPAP protocol for acute respiratory distress. Included were all patients transported by EMS meeting preestablished criteria indicative of acute respiratory distress and CPAP use (patient's problem specified as cardiac, respiratory distress, respiratory disease, or congestive heart failure [CHF]; age ≥ 12 years; chest sounds documented as wheezes or rales; Glascow Coma Scale [GCS] ≥ 11; respiratory rate ≥ 24 breaths per minute; systolic blood pressure ≥ 90 mmHg; and oxygen saturation < 90%). Data were abstracted from ambulance call reports (ACRs) and hospital records. All cases in which "do not resuscitate" (DNR) was documented on the patient chart or ACR or whose in-hospital outcome (death or discharge) was unknown were excluded. Results. In all, 442 patients met the above criteria. The mean (SD) age was 73.0 (13.9) years, and 51.5% were women. In-hospital mortality rates did not differ for these patients: 17/228 (7.5%) in the before group and 17/214 (7.9%) in the after group (p = 0.85). In-hospital intubation rates were similar for both groups (12.7 vs. 14.5%, p = 0.59). An analysis of the subgroup that had a hospital diagnosis of chronic obstructive pulmonary disease (COPD), CHF, or pulmonary edema (n = 273) showed mortality was somewhat lower in the before group (3/138, 2.2%) than in the after group (8/135, 5.9%) (p = 0.13). In-hospital intubation rates were also similar for both groups in this subgroup analysis (11.6 vs. 9.6%, p = 0.61). Conclusion. In contrast to previous studies, we were unable to demonstrate a decrease in intubation or mortality related to the use of prehospital CPAP. Our findings may be specific to our EMS system but suggest that further large-scale, randomized, controlled trials may be warranted to firmly establish the benefit of prehospital CPAP. Key words: airway; continuous positive airway pressure; emergency medical services; paramedic.
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Background: This is an update of a systematic review previously published in 2008 about non-invasive positive pressure ventilation (NPPV). NPPV has been widely used to alleviate signs and symptoms of respiratory distress due to cardiogenic pulmonary oedema. NPPV prevents alveolar collapse and helps redistribute intra-alveolar fluid, improving pulmonary compliance and reducing the pressure of breathing. Objectives: To determine the effectiveness and safety of NPPV in the treatment of adult patients with cardiogenic pulmonary oedema in its acute stage. Search methods: We searched the following databases on 20 April 2011: CENTRAL and DARE, (The Cochrane Library, Issue 2 of 4, 2011); MEDLINE (Ovid, 1950 to April 2011); EMBASE (Ovid, 1980 to April 2011); CINAHL (1982 to April 2011); and LILACS (1982 to April 2011). We also reviewed reference lists of included studies and contacted experts and equipment manufacturers. We did not apply language restrictions. Selection criteria: We selected blinded or unblinded randomised or quasi-randomised clinical trials, reporting on adult patients with acute or acute-on-chronic cardiogenic pulmonary oedema and where NPPV (continuous positive airway pressure (CPAP) or bilevel NPPV) plus standard medical care was compared with standard medical care alone. Data collection and analysis: Two authors independently selected articles and abstracted data using a standardised data collection form. We evaluated study quality with emphasis on allocation concealment, sequence generation allocation, losses to follow-up, outcome assessors, selective outcome reporting and adherence to the intention-to-treat principle. Main results: We included 32 studies (2916 participants), of generally low or uncertain risk of bias. Compared with standard medical care, NPPV significantly reduced hospital mortality (RR 0.66, 95% CI 0.48 to 0.89) and endotracheal intubation (RR 0.52, 95% CI 0.36 to 0.75). We found no difference in hospital length of stay with NPPV; however, intensive care unit stay was reduced by 1 day (WMD -0.89 days, 95% CI -1.33 to -0.45). Compared with standard medical care, we did not observe significant increases in the incidence of acute myocardial infarction with NPPV during its application (RR 1.24, 95% CI 0.79 to 1.95) or after (RR 0.70, 95% CI 0.11 to 4.26). We identified fewer adverse events with NPPV use (in particular progressive respiratory distress and neurological failure (coma)) when compared with standard medical care. Authors' conclusions: NPPV in addition to standard medical care is an effective and safe intervention for the treatment of adult patients with acute cardiogenic pulmonary oedema. The evidence to date on the potential benefit of NPPV in reducing mortality is entirely derived from small-trials and further large-scale trials are needed.
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Background Early use of continuous positive airway pressure (CPAP) has been shown to be beneficial within the setting of acute cardiogenic pulmonary edema (ACPE). The Boussignac CPAP system (BCPAP) was therefore introduced into the protocols of emergency medical services (EMS) in a large urban region. This study evaluates the implementation, practical use and complications of this prehospital treatment. Methods This was a retrospective case series study. The study was carried out in a period shortly after the implementation of the BCPAP system on all EMS ambulances in the The Hague region. According to protocol, diagnosis of ACPE in the prehospital setting was left to the discretion of the EMS paramedics and the facial mask was applied immediately after the diagnosis had been made. Patients were selected through hospital registration and diagnostic criteria for ACPE. Only those patients showing evident clinical signs of ACPE were included. Patient characteristics, physiologic variables, clinical outcomes and complications were collected from EMS transport reports and hospital records. Results Between 1 June 2008 and 30 April 2009 a total of 180 patients were admitted for ACPE. Of these, 76 (42%) had evident clinical signs of ACPE upon presentation and were included. Three patients were transferred and in 14 cases data were missing. Out of the remaining 59 patients, 16 (27%) received BCPAP. In 43 (73%) cases the mask was not applied. For 7 out of 43 cases that were eligible for BCPAP treatment but did not receive the facial mask, an explanation was found in the EMS transport record. No complications were recorded pertaining to using the BCPAP system. Conclusions A significant portion of patients with clinical signs of acute cardiogenic pulmonary edema in the prehospital setting is not treated according to protocol using BCPAP. Based on the small group of patients that actually received BCPAP treatment, the facial mask seems feasible and effective for the treatment of acute cardiogenic pulmonary edema in the prehospital setting.
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Traditionally, Continuous Positive Airway Pressure (CPAP) and Bilevel Positive Airway Pressure (BiPAP) devices have been used to treat patients in acute respiratory failure. However they require an electric power source, are relatively large in size, and may be difficult to use in prehospital settings. The recently introduced Boussignac CPAP system is capable of delivering 10cm H2O of CPAP, is compact, portable and requires only an oxygen source. This paper reviews the efficacy of using Boussignac CPAP as a treatment for acute respiratory failure in both prehospital and hospital settings. All studies mainly focused on patients treated for cardiogenic pulmonary edema. In the prehospital setting, Boussigac CPAP significantly improved respiratory parameters and oxygenation from baseline values. In the emergency department setting, Boussignac CPAP was more effective than standard oxygen delivery and just as effective as BiPAP in improving patient oxygenation and respiration. In one study, implementing Boussignac CPAP reduced intubation rate and hospital stay. Most hospital staff found Boussignac CPAP easy to use and complication rates were low. Boussigac CPAP is a useful device in the treatment of patients with acute respiratory failure, especially in the prehospital setting.
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0.32 to 0.60]) but not incidence of new MI (RR, 1.07 [CI, 0.84 to 1.37]). The effect was more prominent in trials in which myocardial ischemia or infarction caused ACPE in higher proportions of patients (RR, 0.92 [CI, 0.76 to 1.10] when 10% of patients had ischemia or MI vs. 0.43 [CI, 0.17 to 1.07] when 50% had ischemia or MI). Bilevel ventilation reduced the need for intubation (RR, 0.54 [CI, 0.33 to 0.86]) but did not reduce mortality or new MI. No differences were detected between continuous positive airway pressure and bilevel ventilation on any clinical outcomes for which they were directly compared. Limitations: The quality of the evidence base was limited. Definitions, cause, and severity of ACPE differed among the trials, as did patient characteristics and clinical settings. Conclusion: Although a recent large trial contradicts results from previous studies, the evidence in aggregate still supports the use of NIV for patients with ACPE. Continuous positive airway pressure reduces mortality more in patients with ACPE secondary to acute myocardial ischemia or infarction. Primary Funding Source: None.
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Objective: To describe the prehospital use of a continuous positive airway pressure (CPAP) system for the treatment of presumed acute severe pulmonary edema (ASPE). Methods: The efficacy of prehospital CPAP treatment was analyzed in terms of changes in oxygen saturation, need for intubation or ventilatory support, and possible morbidity associated with the CPAP therapy. This was a retrospective cohort study conducted in the mobile intensive care unit of a university hospital. Participants included all consecutive patients with a clinical picture of ASPE treated by a mobile intensive care unit between January 1, 1998, and December 31, 1999. Results: 121 patients were included in this study. 116 patients received prehospital CPAP therapy. Two patients (1.7%) from the CPAP-treated patients were intubated in the field. A total of six patients required endotracheal intubation before hospital, and six other patients after that. After the beginning of CPAP treatment, there was statistically significant elevation in blood oxygen saturation (mean and standard deviation [SD] before CPAP 77% +/- 11% and after CPAP 90% +/- 7%) (p < 0.0001) as well as reductions in the respiratory rate (mean and SD before CPAP 34 +/- 8 breaths/min and after CPAP 28 +/- 8 breaths/min) (p < 0.0001), systolic blood pressure (mean and SD before CPAP 173 +/- 39 mm Hg and after CPAP 166 +/- 37 mm Hg) (p = 0.0002), and heart rate (mean and SD before CPAP 108 +/- 25 beats/min and after CPAP 100 +/- 20 beats/min) (p = 0.0017). The main reason for in-hospital death (8%) was myocardial infarction. No technical problems or complications occurred during CPAP treatment. Conclusions: Prehospital CPAP treatment in patients with ASPE improved oxygenation significantly and lowered respiratory rate, heart rate, and systolic blood pressure. Because of the retrospective nature of this study, the hemodynamic effects of nitroglycerine and morphine cannot be excluded. The mortality rate was low, which needs to be confirmed in a controlled, prospective study.
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Background: The use of continuous positive airway pressure (CPAP) assisted ventilation in the emergency department(ED) has been well described. Objectives: The purpose of this study was to measure the efficacy of adding pre-hospital CPAP to an urban emergency medical service (EMS) respiratory distress protocol on persons with respiratory distress. Methods: A historical cohort analysis of consecutive patients between 2005 and 2010. Groups were matched for severity of respiratory distress. Physiologic variables were the primary outcome obtained from first responders and upon triage in the ED. Additional outcomes included endotracheal intubation rate, hospital mortality, overall hospital length of stay(LOS), intensive care unit (ICU) admission, and ICU length of stay (ICU LOS). Results: There were 410 consecutive patients with predetermined criteria for severe respiratory distress, 235 historical controls matched with 175 post-implementation patients. Average age was 67 years, 54% being male. There were significant median differences in heart and respiratory rates favoring the historical cohort (p < 0.05). There were no significant differences in intubation rate, overall hospital LOS, ICU admission rate, ICU LOS, and hospital mortality (p > 0.05).Patients that were continued on noninvasive ventilatory assistance had a significantly improved rate of intubation and ICU LOS (p < 0.05). Conclusions: The addition of CPAP to our pre-hospital respiratory distress protocol did not improve physiologic variables.There were no differences in overall and ICU LOS between groups. Persons with apparent continued ventilatory assistance appeared to have improved rates of intubation and ICU LOS [corrected].