It's In The Bag: Tidal Volumes in Adult and Pediatric Bag Valve Masks

Abstract

Introduction:
A bag valve mask (BVM) is a life saving device used by all levels of health care professionals during resuscitative care. We focus most of our time optimizing the patient's position, firmly securing the mask, and frequency of ventilations. However, despite our best efforts to control these factors, we may still be precipitating harm to the patient. Multiple studies have shown the tidal volumes typically delivered by the adult BVM are often higher than recommended for lung-protective ventilation protocols. In this study we measure and compare the ventilation parameters delivered by the adult and pediatric BVM ventilators.

Methods:
A RespiTrainer Advance® adult mannequin was used to simulate a patient. Healthcare providers were directed to manually ventilate an intubated mannequin for two minutes using adult and pediatric sized BVMs. Tidal volume, minute ventilation, peak pressure, and respiration rate was recorded.

Results:
The adult BVM provided a mean tidal volume of 807.7mL versus the pediatric BVM providing 630.7mL, both of which exceeded the upper threshold of 560mL of tidal volume necessary for lung protective ventilation of an adult male with an ideal body weight of 70kg. The adult BVM exceeded this threshold by 44.2% versus the pediatric BVM's 12.6% with 93% of participants exceeding the maximum threshold with the adult BVM and 82.3% exceeding it with the pediatric BVM.

Conclusion:
The pediatric BVM in our study provided far more consistent and appropriate ventilation parameters for adult patients compared to an adult BVM, but still exceeded the upper limits of lung protective ventilation parameters. The results of this study highlight the potential dangers in using an adult BVM due to increased risk of pulmonary barotrauma. These higher tidal volumes can contribute to lung injury. This study confirms that smaller BVMs may provide safer ventilatory parameters. Future studies should focus on patient-centered outcomes with BVM.

Full text

UC Irvine
Western Journal of Emergency Medicine: Integrating Emergency
Care with Population Health
Title
It’s In The Bag: Tidal Volumes in Adult and Pediatric Bag Valve Masks
Permalink
https://escholarship.org/uc/item/37z118tt
Journal
Western Journal of Emergency Medicine: Integrating Emergency Care with Population
Health, 0(0)
ISSN
1936-900X
Authors
Dafilou, Benjamin
Schwester, Daniel
Ruhl, Nathan
et al.
Publication Date
2020-04-27
License
https://creativecommons.org/licenses/by/4.0/ 4.0
Peer reviewed
eScholarship.org Powered by the California Digital Library
University of California

Articles in Press 1 Western Journal of Emergency Medicine
Original research
It’s In The Bag: Tidal Volumes in Adult and Pediatric
Bag Valve Masks
Benjamin Dalou, BA*
Daniel Schwester, MICP*
Nathan Ruhl, PhD†
Andreia Marques-Baptista, MD*
Section Editor: Gabriel Wardi, MD
Submission history: Submitted November 4, 2019; Revision received March 19, 2020; Accepted March 11, 2020
Electronically published April 27, 2020
Full text available through open access at http://escholarship.org/uc/uciem_westjem
DOI: 10.5811/westjem.2020.3.45788
Capital Health Hospital System, Department of Emergency Medical Services, Trenton,
New Jersey
Rowan University, Department of Biological Sciences, Glassboro, New Jersey
*
†
Introduction: A bag valve mask (BVM) is a life saving device used by all levels of health care
professionals during resuscitative care. We focus most of our time optimizing the patient’s position, rmly
securing the mask, and frequency of ventilations. However, despite our best efforts to control these
factors, we may still be precipitating harm to the patient. Multiple studies have shown the tidal volumes
typically delivered by the adult BVM are often higher than recommended for lung-protective ventilation
protocols. In this study we measure and compare the ventilation parameters delivered by the adult and
pediatric BVM ventilators.
Methods: A RespiTrainer Advance® adult mannequin was used to simulate a patient. Healthcare
providers were directed to manually ventilate an intubated mannequin for two minutes using adult and
pediatric sized BVMs. Tidal volume, minute ventilation, peak pressure, and respiration rate was recorded.
Results: The adult BVM provided a mean tidal volume of 807.7mL versus the pediatric BVM providing
630.7mL, both of which exceeded the upper threshold of 560mL of tidal volume necessary for lung
protective ventilation of an adult male with an ideal body weight of 70kg. The adult BVM exceeded this
threshold by 44.2% versus the pediatric BVM’s 12.6% with 93% of participants exceeding the maximum
threshold with the adult BVM and 82.3% exceeding it with the pediatric BVM.
Conclusion: The pediatric BVM in our study provided far more consistent and appropriate ventilation
parameters for adult patients compared to an adult BVM, but still exceeded the upper limits of lung
protective ventilation parameters. The results of this study highlight the potential dangers in using an adult
BVM due to increased risk of pulmonary barotrauma. These higher tidal volumes can contribute to lung
injury. This study conrms that smaller BVMs may provide safer ventilatory parameters. Future studies
should focus on patient-centered outcomes with BVM. [West J Emerg Med. 2020;21(3)X–X.]
INTRODUCTION
High volumes delivered during positive pressure ventilation
can precipitate lung injury in a patient already suffering from an
underlying pulmonary pathology. Barotrauma refers to damage
sustained to the lung from rapid or excessive increases in
pressure. Volutrauma describes structural lung injury due to
over-distention of the alveoli that occurs when higher than
physiologic volumes are delivered. Barotrauma is dened as
trauma caused by rapid or extreme changes in pressure affecting
enclosed cavities within the body.1 Positive pressure ventilation
provided via bag valve masks (BVMs) may expose patients to
high airway pressures and volumes, potentiating similar alveolar
damage. Conditions such as interstitial emphysema,
pneumothorax, pneumomediastinum, subcutaneous emphysema,
and pneumoperitoneum are clinical presentations of barotrauma.2
The purpose of the study is to determine whether healthcare
providers are unintentionally delivering pressures and volumes
that could potentiate injury during manual ventilation using

Western Journal of Emergency Medicine 2 Articles in Press
Tidal Volumes in Adult and Pediatric BVMs Dalouetal.
Population Health Research Capsule
What do we already know about this issue?
Healthcare providers at all levels are generally
very ineffective at providing appropriate
ventilations with bag valve masks.
What was the research question?
Whether bag valve masks (BVM) provide
appropriate tidal volume for lung protective
ventilation.
What was the major nding of the study?
The tidal volumes provided by standard size
BVMs signicantly exceed safe thresholds for
lung protective ventilation.
How does this improve population health?
BVMs are used widely to resuscitate and
ventilate critically ill patients, and they may
actually be causing harm in practical use.
BVMs.
Stroke volumes of BVMs are dened by the manufacturer as
the projected delivered tidal volume by manually squeezing the
bag. To achieve lung-protective ventilation for intubated patients,
the average tidal volume should be between 5-8 milliliters per
kilogram (mL/kg) of ideal body weight.3,4,5.6 The reservoirs of
adult BVMs contain between 1500-2000 mL of air, depending on
manufacturer and model, with projected stroke volumes of
between 900-1000 mL.7,8,9 The volume of pediatric BVMs can
range anywhere between 500-1000 mL with stroke volumes of
450-650 mL,7,8,9 closer to the targeted tidal volume for adult
patients who are critically ill or in cardiac arrest.3 We assessed
adult and pediatric BVM ventilation in a simulated scenario,
comparing the mean tidal volume, peak pressure, and respiratory
rate for each.
METHODS
Study Setting
This study took place at Capital Health Hopewell Medical
Center, Capital Health Regional Medical Center, and the 2016
New Jersey Statewide Conference on Emergency Medical
Services (EMS). One hundred and thirty people participated in
this study: 1 patient care advocate, 1 licensed practical nurse, 4
respiratory therapists, 5 physician assistants, 11 critical care
technicians, 13 medical doctors, 25 paramedics, 28 emergency
medical technicians, and 42 registered nurses. All participants are
active health care providers working in the in-hospital or pre-
hospital setting. All data was collected between September and
October of 2016. Participants were selected out of convenience
and those willing to participate.
Study Design
Institutional Review Board approval was given for this
study. This study was conducted using the QuickLung
RespiTrainer Advance® set to the adult setting, which means
that the respiratory mechanics were set to a compliance of 50
milliliters per centimeter of water (mL/cm H2O) and a resistance
of 5 centimeters of water per liter per second (cmH2O/L/s).
These settings allowed for the RespiTrainer® to accurately
calculate tidal volumes (Vt), peak pressures (Ppeak), breath rates
(BR), and minute ventilations (MV). Ppeak was recorded by the
RespiTrainer Advance as the highest value of pressure during a
single positive pressure ventilation. MV is calculated by the
RespiTrainer Advance as the prorated average tidal volume per
minute from a sample of one breath. BR were calculated by the
RespiTrainer Advance in real time from the previous breath and
reported as the average of these measurements. Vt were
calculated by Vt = (Ppeak - Pmin) / (50 mL/cm H2O)
The RespiTrainer® was intubated with a standard size 7.5
millimeters (mm) endotracheal tube at 25 centimeters (cm) at the
lip. The endotracheal cuff was then inated with 10 mL of air.
The chest rise mechanism was not utilized during data collection
because, during a real cardiac arrest, clinicians providing
ventilations would not be able to see chest rise while
compressions were in progress in an intubated patient. An
AirFlow AF1140MB Adult BVM® and an AirFlow AF2140MB
Pediatric BVM® were used for this study. The range of tidal
volumes used for this study for an adult male patient with an ideal
body weight of 70 kg was 350-560 mL based off a lung
protective range of 5-8 mL/kg.10 The adult BVM, an AirFlow
AF1140MB, had a maximum capacity of 1900mL and the
pediatric BVM, an AirFlow AF2140MB, had a maximum
capacity of 1000mL.
A simulated cardiac arrest scenario was selected to encourage
providers to ventilate slowly and use lower volumes. This
standardized approach allowed observation of the true ventilatory
metrics delivered when using the two BVMs. Prior to data
collection, each participant was given the following instruction:
“You are in a cardiac arrest scenario. You have been directed to
provide ventilations to an adult intubated patient for two minutes
of cardio-pulmonary resuscitation (CPR) using an adult BVM;
and then another two minutes, using a pediatric BVM.” Each
participant was instructed that they were only responsible for
ventilations; they did not need to provide compressions,
medications, pause for pulse checks or any other CPR related
activity. The only demographic information collected for the
participants was their highest medical certication level.
Statistical Analysis
All data was analyzed using JMP 12.0. Sample size was not
sufcient to test for interactive effects between the different
metrics of BVM performance (tidal volume, peak pressure,

Articles in Press 3 Western Journal of Emergency Medicine
Dalou et al. Tidal Volumes in Adult and Pediatric BVMs
respiration rate and minute ventilation) and the different
certication types of study participants, so differences in adult
vs. pediatric BVM performance were analyzed using discrete
Wilcoxon signed-rank tests (paired differences). Wilcoxon
signed-rank tests were also used to compare tidal volume for
both adult and pediatric BVMs to an idealized upper-threshold
of 560 mL (upper threshold for an adult male with an ideal body
weight of 70 kg).3
RESULTS
The four metrics measured during this study were tidal
volume in mL, respiratory rate in breaths per minute (bpm), peak
pressure in cmH2O, and minute ventilation in liters (L). There
was a signicant difference between adult and pediatric BVM
performance (Table 1) as measured by tidal volume (p=<0.001),
peak pressure (p=<0.001), and minute ventilation (p=<0.001), but
not respiration rate (p=0.549).
The mean tidal volume measured using the adult BVM was
807.7 mL versus the pediatric BVM mean tidal volume of 630.7
mL. The mean peak pressure measured in the adult BVM was 17
cmH2O versus the mean peak pressure of the pediatric BVM of
13.4 cmH2O. The mean minute ventilation measured for the
adult BVM was 11.6 L versus 8.8 L for the pediatric BVM. The
mean respiration rate measured with the adult BVM was 14.2
bpm versus 13.9 bpm in the pediatric BVM group.
Tidal volume for both adult (p=<0.001) and pediatric
(p=<0.001) BVMs signicantly exceeded the threshold of 560
mL for an adult male with an ideal body weight of 70 kg, but the
difference was far greater for the adult BVM (Figure 1A; adult
mean tidal volume = 807.7 mL; pediatric mean tidal volume =
630.7 mL). The mean tidal volume delivered by the adult BVM
exceeded the upper threshold of 560 mL for an adult male with an
ideal body weight of 70 kg patient by 44.2%, versus the pediatric
BVM where the mean tidal volume exceeded the upper threshold
by 12.6%. The mean measured peak pressure for the adult BVM
was 26.9% higher than it was in the pediatric BVM. The mean
measured minute ventilation for the adult BVM was 31.8%
higher than it was in the pediatric BVM.
While both BVMs are capable of delivering appropriate tidal
volumes, 93% (n=121) of participants exceeded the upper
threshold for tidal volumes using the adult BVM and 82.3%
(n=107) exceeded the upper threshold for tidal volumes using the
pediatric BVM.
DISCUSSION
Studies have shown that ventilation using low tidal
volumes is associated with reduced morbidity and
mortality.4,5,6,11,12 Higher tidal volumes can lead to increased
organ dysfunction and inammation in intubated patients.5,6
Ideal conditions for intubated patients on mechanical ventilation
is a tidal volume of 5-8 mL/kg, or 350-560 mL in an adult male
with an ideal body weight of 70 kg.10 Most providers in our
study ventilated the simulator mannequin with over 800 mL of
tidal volume using the adult BVM (Figure 1A and Table 1),
which is over 200 mL higher than the upper threshold of most
recommended lung-protective ventilator settings.13 The pediatric
BVM provided slightly elevated, but more physiologically
appropriate, tidal volumes and peak pressures for adult patients.
Although our study was not conducted on patients, exceeding
the physiologically appropriate metrics could have a negative
impact on patient care due to the consequences of barotrauma
and volutrauma. Studies have consistently shown low volume
mechanical ventilation in the setting of acute lung injury results
in signicantly lower mortality.11,12
There was no signicant difference in breaths per minute
when using the BVMs. This is signicant because even in a
simulated environment under ideal conditions all providers
consistently ventilated above the recommended rate 8-10 bpm in
a cardiac arrest scenario.14 Ventilating at higher than
recommended rates potentiates the damage caused by the higher
volumes and pressures. As shown in Figure 1B, there was no
signicant difference in respiratory rate between the adult and
pediatric BVMs, which indicates that participants understood the
directions correctly and did not switch ventilatory rates when
switching BVMs.
This study adds to an emerging body of literature on the use
of smaller BVMs5 for achieving closer to ideal physiologic
parameters during manual ventilations of intubated patients.4,5,6
Siegler et al examined whether or not pediatric BVMs could
provide sufcient tidal volume to adult patients via several
different airway securing devices. Though they had a smaller
cohort, their results were similar to our own.
Adult Pediatric Wilcoxon Signed-Rank Test
BVM metric Mean SD Mean SD Difference SD P value
Tidal volume (mL) 807.7 160.3 630.7 84.9 177 111.9 <0.001
Respiration rate (RR) 14.2 6.7 13.9 6.6 0.3 3.2 0.549
Peak pressure (cm H2O) 17 3.8 13.4 2.4 3.6 2.3 <0.001
Minute ventilation (L) 11.6 6.1 8.8 4.7 2.7 2.9 <0.001
Table 1. Mean and standard deviation (SD) for adult and pediatric bag valve mask metrics and results from Wilcoxon Signed-Rank analysis.
BVM, bag valve mask; mL, milliliters; RR, respirations per minute; cm H2O, centimeters of water; L, liters.
Differences were calculated as Adult-Pediatric; positive values indicate adult metrics were higher.

Western Journal of Emergency Medicine 4 Articles in Press
Tidal Volumes in Adult and Pediatric BVMs Dalouetal.
Tidal volume (mL)
Adult Pediatric Adult Pediatric
Respiration rate (respirations/min)
Figure 1. Side-by-side boxplots of adult vs. pediatric for mean tidal volume (A) and mean respiration rate (B). The dashed line in A
represents the idealized upper threshold for an adult male with an ideal body weight of 70 kilograms (kg) at 8 milliliters (mL)/kg, or 560 mL.
BVM, bag valve mask; min, minutes.
BVM type BVM type
AB
LIMITATIONS
This study is limited to the accuracy of the Quick Lung
RespiTrainer Advance®. It is a very advanced simulator, but it
assumes standard pulmonary compliance and resistance
whereas human subjects vary widely and signicantly. This
study was conducted under a controlled environment that
differs from a true patient care situation.15 We did not
randomize the order in which we conducted ventilations with
the different BVM types, so it is possible that some amount of
variation between BVM types could be due to factors such as
fatigue, but the observation that respiratory rate did not
decline between treatments (Figure 1B) indicates that fatigue
was not a meaningful issue in this study. We were also limited
by the fact that this study does not include human patients and
therefore could not measure patient outcomes or
complications. The fact that the adult BVM was always used
rst may have inuenced subjects to provide more volume
with the pediatric BVM because the order was not
randomized. Also, the lack of chest wall movement because
this was a simulated cardiac arrest scenario may have caused
subjects to provide more volume than they normally would if
chest compressions were not being performed. Additionally,
although we were simulating a cardiac arrest scenario because
we did not use the chest rise function of the mannequin
participants may have overventilated the mannequin due to
not being able to see chest rise. This study was also limited
because it only did an analysis for an adult male patient with
an ideal body weight of 70 kg, this is signicantly higher than
a female adult patient.
CONCLUSION
The results of this study showed extreme tidal volumes
were delivered while using a standard size adult BVM. The
pediatric BVM in our study provided far more consistent and
appropriate ventilation compared to an adult BVM in a
simulated adult patient, though it still exceeded upper limits
for lung-protective ventilation. Additional data obtained from
clinical trials comparing a smaller or newly designed BVM to
standard BVM are needed; however, it seems prudent to
consider reducing the size or redesigning the standard adult
BVM to minimize the risk of barotrauma.
Address for Correspondence: Benjamin Dalou, BA, Capital
Health Hospital System, Department of Emergency Medical
Services, 433 Bellevue Avenue, Trenton, NJ 08618. Email:
bdalou@gmail.com.
Conicts of Interest: By the WestJEM article submission agreement,
all authors are required to disclose all afliations, funding sources
and nancial or management relationships that could be perceived
as potential sources of bias. No author has professional or nancial
relationships with any companies that are relevant to this study.
There are no conicts of interest or sources of funding to declare.
Copyright: © 2020 Dalou et al. This is an open access article
distributed in accordance with the terms of the Creative Commons
Attribution (CC BY 4.0) License. See: http://creativecommons.org/
licenses/by/4.0/

Articles in Press 5 Western Journal of Emergency Medicine
Dalou et al. Tidal Volumes in Adult and Pediatric BVMs
REFERENCES
1. Jr. WCS. Barotrauma. MedicineNet. Available at: https://www.
medicinenet.com/script/main/art.asp?articlekey=31722. Accessed
January 6, 2020.
2. US Naval Sea Systems Command. US Navy Diving Manual. 6th ed.
United States; 2006.
3. Siegler J, Kroll M, Wojcik S, et al. Can EMS Providers Provide
Appropriate Tidal Volumes in a Simulated Adult-sized Patient with a
Pediatric-sized Bag-Valve-Mask? Prehosp Emerg Care.
2016;21(1):74-8.
4. Gu W-J, Wang F, Liu J-C. Effect of lung-protective ventilation with
lower tidal volumes on clinical outcomes among patients undergoing
surgery: a meta-analysis of randomized controlled trials. CMAJ.
2015;187(3):101-9.
5. Lellouche F, Dionne S, Simard S, et al. High Tidal Volumes in
Mechanically Ventilated Patients Increase Organ Dysfunction after
Cardiac Surgery. Anesthesiology. 2012;116(5):1072-82.
6. Oliveira RPD, Hetzel M, Silva MDA, et al. Mechanical ventilation with
high tidal volume induces inammation in patients without lung
disease. Crit Care. 2010;14(2):R39.
7. Ventlab. Airow Manual Resuscitator. Airow Manual Resuscitator.
2017.
8. Ambu. Ambu Spur II. Ambu Spur II. 2017.
9. Intersurgical. Bag-Valve-Mask (BVM) manual resuscitation
systems. Bag-Valve-Mask (BVM) manual resuscitation systems. 2017.
10. Kilickaya O, Gajic O. Initial ventilator settings for critically ill
patients. Crit Care. 2013;17:123.
11. Ventilation with Lower Tidal Volumes as Compared with Traditional
Tidal Volumes for Acute Lung Injury and the Acute Respiratory
Distress Syndrome. N Engl J Med. 2000;342(18):1301-8.
12. Amato MBP, Barbas CSV, Medeiros DM, et al. Effect of a Protective-
Ventilation Strategy on Mortality in the Acute Respiratory Distress
Syndrome. N Engl J Med. 1998;338(6):347-54.
13. Brower RG, Matthay MA, Morris A, et al. Ventilation with Lower Tidal
Volumes as Compared with Traditional Tidal Volumes for Acute Lung
Injury and the Acute Respiratory Distress Syndrome. N Engl J Med.
2000;342(18):1301-8.
14. Link MS, Berkow LC, Kudenchuk PJ, et al. Part 7: Adult Advanced
Cardiovascular Life Support. Circulation. 2015;132(18):444-64.
15. Elling R, Politis J. An evaluation of emergency medical technicians
ability to use manual ventilation devices. Ann Emerg Med.
1983;12(12):765-8.