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Anesth Pain Med. 2022 June; 12(3):e123205.
Published online 2022 August 15.
doi: 10.5812/aapm-123205.
Research Article
Evaluation of Ventilation with Nasal Versus Face Mask After General
Anesthesia Induction in Pediatric Patients
Omid Aghadavoudi 1, Dorsa Beheshtiparvar 2and Amir Shafa 3, *
1Department of Anesthesiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
2School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
3Anesthesiology Department, Isfahan University of Medical Sciences, Isfahan, Iran
*Corresponding author: Anesthesiology Department, Isfahan University of Medical Sciences, Isfahan, Iran. Email: shafa_amir@yahoo.com
Received 2022 February 07; Revised 2022 April 10; Accepted 2022 July 19.
Abstract
Background: Because of some difficulties during face mask ventilation in unconscious patients, such as upper airway obstruction
patients, we conducted this study to compare nasal and face mask ventilation during general anesthesia induction.
Methods: In this clinical trial study, 70 patients between 3 and 12 years old undergoing elective lower abdominal surgery with gen-
eral anesthesia were randomly divided into two groups. After administration of induction agents, one group was ventilated with
the face mask and 100% oxygenation in three minutes and the other with the nasal mask. The mean expiratory volume, airway pres-
sure, end-tidal CO2(EtCO2), blood oxygen saturation (SpO2), and hemodynamic factors were recorded and compared in the baseline,
two minutes after mask ventilation, and five minutes after intubation.
Results: The mean EtCO2in the second minute after ventilation was significantly higher in the nasal mask group than in the face
mask group (P = 0.04). However, in the fifth minute after intubation, there was no significant difference between the two groups (P
= 0.31). Other factors related to ventilation did not significantly differ between the two groups.
Conclusions: It can be concluded that nasal mask ventilation is as effective as facial mask ventilation. The nasal mask can replace
the face mask if there is difficult face mask ventilation or airway obstruction.
Keywords: Face Mask, Nasal Mask, Ventilation, General Anesthesia
1. Background
Effective mask ventilation is vital during general anes-
thesia; however, upper airway obstruction is a cause of dif-
ficult mask ventilation and a common clinical problem af-
ter anesthesia induction, especially in children (1-3). The
overall incidence of difficult mask ventilation is 1.4% dur-
ing general anesthesia in adults and 0.15% in cases of mask
ventilation (4). However, the rate of difficult mask venti-
lation in children is 6.6%, even in populations where diffi-
cult ventilation is expected with a mask (2). Children have
relatively larger heads, tongues, and adenoids, and adeno-
tonsillar hypertrophy is more common in preschool and
older children, which is a common cause of ear, nose, and
throat elective surgery and is the narrowest part of the air-
way at the level of the tonsils. These anatomical features
may make airway obstruction more likely in children dur-
ing anesthesia (5,6).
In one study, the incidence of difficult ventilation with
a mask was 5%, which was significantly associated with in-
tubation. In this study, factors such as having a beard,
obesity (BMI above 26), no teeth or lack of teeth, age over
55 years, and a history of snoring and difficult ventilation
were effective and predictive factors of difficult ventilation
(4). Meanwhile, when anesthesiologists use masks, one of
the common problems is the possibility of damage to the
eyes and nerves of the face, especially in people hospital-
ized with trauma to the face and eyes. In these people, it
is impossible to press the mask firmly and create a proper
seal; hence the proper ventilation is not done (7). Radio-
logical studies have shown that neck extension is the most
effective maneuver to keep the throat open. Applying force
from behind the temporomandibular joint to the front can
also be helpful. If these two maneuvers are not successful,
tools such as oropharyngeal airway and nasopharyngeal
airway should be used (8-10).
Face mask ventilation is a fundamental skill that re-
quires technical and accurate comment. Using a face mask
(on the nose and mouth simultaneously) with sponta-
neous breathing throughout the induction and mainte-
nance of anesthesia with inhalants is the simplest and least
invasive method of anesthesia for short surgery. It is ap-
Copyright © 2022, Author(s). This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License
(http://creativecommons.org/licenses/by-nc/4.0/) which permits copy and redistribute the material just in noncommercial usages, provided the original work is properly
cited.
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Aghadavoudi O et al.
propriate for all patients except those who vomit and re-
turn food. Face masks are also used for controlled venti-
lation before and after the endotracheal tube. Face masks
are designed to cover the patient’s mouth and nose. There
are two main points in using a mask: The complete seal-
ing between the face and the mask and the absence of gas
leakage, and the openness of the patient’s airways, which
should always be checked. The quality of the seal in spon-
taneous ventilation is determined by the filling and move-
ments of the mask storage bag. Gas leakage usually occurs
around the nose and cheeks. On the other hand, the symp-
toms of airway obstruction depend on the location and ex-
tent of the obstruction and whether positive pressure or
spontaneous breathing method is used. The most critical
sign of clinical airway obstruction is vocal breathing (snor-
ing occurs in supraglottic obstruction and tail stridor oc-
curs in gluteal obstruction), which is a classical sign of air-
way obstruction in spontaneous breathing (8).
A study of 17 patients over 18 years of age under gen-
eral anesthesia showed that nasal ventilation was more
effective than general ventilation in adults who expelled
more respiratory carbon dioxide from the lungs (11). In an-
other study performed on 73 patients with a mean age of
48 years (18 - 65 years) under general anesthesia, more cur-
rent volume was provided for patients under ventilation
with nasal anatomical masks than those with anatomical
facial masks. Therefore, nasal mask ventilation was more
efficient than face mask ventilation. Nasal mask ventila-
tion during anesthesia also provides more efficiency and
safety than anatomical mask ventilation in the natural po-
sition of the neck (12).
2. Objectives
Since gas leakage may occur around the nose and
cheeks in anatomical face mask ventilation while it is not
possible to press the mask firmly and create a proper seal,
especially in people hospitalized with trauma to the face
and eyes, and airway obstruction is more likely in children
due to their anatomical condition, it is assumed that there
will be fewer problems in nasal mask ventilation. In addi-
tion, since the positive pressure is not applied to the soft
tissue of the tongue and mouth in nasal mask ventilation,
the entire volume of the tail enters the larynx and airway
through a relatively hard-nosed route. Also, the pressure
gradient between the nasopharynx and oropharynx moves
the tongue and palate forward, resulting in less airway
obstruction during ventilation that is more pronounced
in patients with ventilation. Therefore, the present study
compared nasal mask ventilation with anatomical face
mask ventilation in the age group of 3 to 12 years.
3. Methods
This study is a single-blind randomized clinical trial.
The study population included all patients aged 3 to 12
years who were candidates for elective lower abdomi-
nal surgery under general anesthesia in Al-Zahra Hospital
from January 2020 to May 2021.
The sample was calculated as 35 patients in each group
with a confidence level of 95%, 80% test power, and the stan-
dard deviation of 4.5 and 0.2, based on the previous studies
(11) on the difference in mean volume of carbon dioxide per
breath equal to 5.
The inclusion criteria included all patients candidates
for elective lower abdominal surgery with general anesthe-
sia, age of 3 - 12 years, no obstruction in the nasal passage,
no airway obstruction (such as hypertrophy of the ade-
noids, tonsils, and tongue), any obvious deformity or frac-
ture of the face, and no acute or chronic lung disease. The
exclusion criteria included changing the anesthesia plan
from general to regional. In case ventilation was impossi-
ble, we used an oropharyngeal airway and an anatomical
face mask with neck extension.
After obtaining the code of ethics from the Medical
Ethics Committee of Isfahan University of Medical Sciences
(approved code: IR.MUI.REC.1395.3.424), clinical trial code
(NCT05018468), and consent of patients’ parents, inclu-
sion criteria for all patients were evaluated by an anes-
thesiologist and the necessary explanations were given to
the patients’ supervisors. They were given necessary in-
structions before the operation, and fluid therapy was sup-
plied during fasting and premedication. On the day of
surgery, after premedication with midazolam (0.05 mg
kg-1) and ketamine (0.5 mg kg-1 ) and placement on the oper-
ating room bed, patients underwent pre-oxygenation with
a mask near the face of O2100% for three minutes. Then,
anesthesia induction drugs, including thiopental sodium
5 mg kg-1, atracurium 0.5 mg kg-1 , and fentanyl 2 µg kg-1
were given to all patients. At this time, the patients were
randomly divided into two groups of 35 (Figure 1).
The first group was ventilated with an anatomical face
mask and 100% oxygen for three minutes. In the second
group, ventilation was performed through a nasal mask
and 100% oxygen for three minutes. In both groups, ven-
tilation was performed with the help of the anesthesia ma-
chine control mode with a volume of 8 cc kg-1 and a speed
of 12 - 20 breath/ min-1 . The mean expiratory flow volume,
mean volumes of SpO2and EtCO2, and mean volume of
maximum airway pressure in three consecutive breaths in
the second minute after ventilation initiation were mea-
sured in both groups (13). After endotracheal intubation
and fixation of the tube and its connection to the anes-
thesia machine, these parameters were measured again in
2 Anesth Pain Med. 2022; 12(3):e123205.
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Aghadavoudi O et al.
Assessed for eligibility (n = 75)
Excluded (n = 0)
- Not meeting inclusion criteria (n = 3)
- Declined to participate (n = 2)
- Other reasons (n = 0)
Enrollment
Randomized (n = 70)
Allocated to intervention group (n = 35)
(ventilated with facial mask and 100%
oxygenation in three minutes)
Received allocated intervention (n = 35)
Did not receive allocated intervention
(n = 0)
Allocated to intervention group (n = 35)
(ventilated with the nasal mask)
Received allocated Intervention (n = 35)
Did not receive allocated intervention
(n = 0)
Allocation
Follow-Up
Analysis
Lost to follow- up (n = 0)
Discontinued intervention
(n = 0)
Lost to follow-up (n = 0)
Discontinued intervention (n = 0)
Analyzed (n = 35)
- Excluded from analysis
(n = 0)
Analyzed (n = 35)
- Excluded from analysis
(n = 0)
Figure 1. Consort flowchart of patients
the fifth minute after endotracheal intubation. Hemody-
namic changes, including heart rate and systolic and dias-
tolic blood pressure, were also recorded and compared be-
tween both groups.
Finally, the collected data were entered into SPSS soft-
ware (ver. 25). Data were presented as means ±stan-
dard deviation (SD) or n (%). As the Kolmogorov-Smirnov
test showed that data distribution was normal, an inde-
pendent t-test was used to compare the mean of quantita-
tive variables between the two groups. Fisher’s exact test
was used to compare qualitative variables between the two
groups. The significance level in all analyses was consid-
ered less than 0.05.
4. Results
There were 32 (91.4%) boys and three (8.6%) girls with a
mean age of 4.5 ±2.2 years and a mean weight of 15.2 ±5.3
kg in the nasal mask group and 32 (91.4%) boys and three
(8.6%) girls with a mean age of 4.3 ±1.9 years and a mean
weight of 14.5 ±4.4 kg (P value > 0.05) in the face mask
group.
The mean expiratory tidal volume and maximal air-
way pressure in three consecutive breaths were not signif-
icantly different between the two groups at any time (P
value > 0.05). The mean EtCO2in the second minute af-
ter the start of ventilation was significantly higher in the
nasal mask group than in the face mask group (P value =
0.04), but there was no significant difference between the
two groups in the fifth minute after endotracheal intuba-
tion (P value = 0.31) (Table 1).
The mean SPO2and heart rate were not significantly
different between the two groups in any of the three times
(P value > 0.05). Mean systolic blood pressure, diastolic
blood pressure, and mean arterial blood pressure (MAP) at
baseline were not significantly different between the two
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Aghadavoudi O et al.
Table1. Comparison of Parameters Related to Quality of Ventilation Between Two Groups a
Variables Time Face Mask Group Nasal Mask Group P-Value
Expiratory flow volume (mL) Second minute after the start of ventilation 117.7 ±28.6 123.9 ±32.3 0.403
Fifth minute after endotracheal intubation 139.4 ±41.7 135.8 ±34.1 0.701
Maximum airway pressure (CmH2O) Second minute after the start of ventilation 12.5 ±1.9 13.02 ±2.1 0.228
Fifth minute after endotracheal intubation 15.4 ±2.04 16.2 ±2.2 0.123
EtCO2(mmHg) Second minute after the start of ventilation 29.5 ±4 31.4 ±3.5 0.041
Fifth minute after endotracheal intubation 37.2 ±2.8 38.2 ±4.9 0.312
aValues are expressed as mean ±SD.
groups (P value > 0.05) but were significantly lower in the
nasal mask group than in the face mask group at the sub-
sequent times (P value < 0.05) (Table 2).
Also, there was no significant difference between the
two groups in the frequency of SPO2drop (P value = 0.12)
and the impossibility of ventilation (P value = 0.50) during
masking (Table 3).
5. Discussion
In the present study, we compared ventilation quality
after general anesthesia induction in children aged 3 to 12
years using a face anatomical mask or nasal mask. Based
on the results, considering the first type error of 5% and
a significance level of 0.05, we measured EtCO2in the sec-
ond minute after the start of ventilation and systolic, dias-
tolic, and moderate blood pressure in the second minute
after the start of ventilation and the fifth minute after intu-
bation, showing a significant difference between the two
groups so that blood pressure variables were lower and
EtCO2was higher in the nasal mask group. Other vari-
ables such as heart rate, oxygen pressure, oxygen pressure
drop, mean expiratory volume, mean EtCO2, and mean air-
way pressure did not differ significantly between the two
groups of masking methods. However, the results notably
indicate that both methods significantly affected ventila-
tion and despite the difference in blood pressure param-
eters between the two groups, the difference between the
two methods in these parameters was in the normal range.
It should be noted that although EtCO2was higher in the
nasal mask group than in the other group, EtCO2in both
groups was within the normal range due to the 95% confi-
dence interval.
In other words, it can be said that EtCO2in the second
minute after initiating ventilation in the nasal mask group
was significantly better than that in the face mask group,
and in the fifth minute after endotracheal intubation, no
significant difference was found between the two groups.
Therefore, it may be better to ventilate the nasal airway in
children than in the face. In fact, it can be said that as the
nasal mask method is preferred in patients with difficult
mask ventilation, the nasal airway ventilation method can
be used in children (especially those with difficult mask
ventilation).
Nasal mask ventilation is commonly used in short-
term anesthesia, such as anesthesia in dental procedures
and continuous positive airway pressure (CPAP) in people
with obstructive sleep apnea to create positive airway pres-
sure (7,14). In the latter case, it significantly affects CPAP
due to the physical prevention of upper airway overlap
(11). Therefore, it is a reason for justifying nasal masks in
general anesthesia. When installing a nasal mask, increas-
ing the pressure in the nasal cavity and not increasing the
pressure in the oral cavity causes a pressure difference be-
tween the nasopharynx and the oral cavity, which helps
push back the soft palate and tongue and prevent the col-
lapse. However, when using a full face mask, an increase
in pressure is created in the oral cavity, and this pressure
difference is not achieved.
Several studies have compared the quality of ventila-
tion after general anesthesia induction with two methods
of mask ventilation. Some have reported the superiority
of the nasal mask over the face mask in terms of ventila-
tion parameters for CPAP ventilation. This discrepancy can
be explained by the difference in pressure and the positive
pressure that the nasal mask creates, preventing the col-
lapse and obstruction of the upper airway (15-17). It has also
been shown that a better compliance nasal mask is more
comfortable in CPAP and has less gas leakage (18).
In 2008, Liang et al. (11) examined ventilation with a
nasal mask compared to a combined nasal and oral mask.
In this study performed on 17 patients, the patients first un-
derwent ventilation with a combination mask and then a
nasal mask. According to the results, the nasal mask had
significantly more effective ventilation than the mouth-
nose mask, and less carbon dioxide pressure, more oxy-
gen pressure, and more expiratory tidal volume were ob-
tained. Although our study tried to prove the superiority of
4 Anesth Pain Med. 2022; 12(3):e123205.
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Aghadavoudi O et al.
Table2. Mean SPO2, Systolic and Diastolic Blood Pressure, Mean Arterial Blood Pressure (MAP), and Heart Rate at Different Times in the Two Groups a
Variables Time Face Mask Group Nasal Mask Group P-Value
SPO2(%)
Baseline 94.7 ±2.4 95.3 ±2.4 0.301
Second minute after the start of ventilation 97.7 ±1.8 97.2 ±3.1 0.368
Fifth minute after endotracheal intubation 98.3 ±1.7 98.2 ±1.9 0.692
Systolic blood pressure (mmHg)
Baseline 96.8 ±7.6 94.2 ±6.2 0.124
Second minute after the start of ventilation 95.3 ±8.5 89.6 ±6.4 0.002
Fifth minute after endotracheal intubation 95.6 ±7.9 90.4 ±6.7 0.005
Diastolic blood pressure (mmHg)
Baseline 44.3 ±6 43.3 ±4.8 0.419
Second minute after the start of ventilation 43.9 ±7.1 41 ±4.4 0.041
Fifth minute after endotracheal intubation 44.2 ±6.4 41.4 ±5.03 0.049
MAP (mmHg)
Baseline 61.8 ±6.04 60.3 ±4.9 0.244
Second minute after the start of ventilation 61 ±7.2 57.2 ±4.4 0.009
Fifth minute after endotracheal intubation 61.3 ±6.4 57.8 ±5.1 0.012
Heart rate (bpm)
Baseline 125.9 ±10.6 123.6 ±8.8 0.307
Second minute after the start of ventilation 135.5 ±12.2 130.5 ±9.5 0.062
Fifth minute after endotracheal intubation 127.3 ±10.1 126.3 ±5.7 0.662
aValues are expressed as mean ±SD.
Table 3. Frequency Distribution of SPO2Drop and Impossibility of Ventilation Dur-
ing Masking Time in Two Groups a
Variables Face Mask Group Nasal Mask Group P-Value
Drop SPO20 (0) 3 (8.6) 0.12
Impossibility of
ventilation
0 (0) 1 (2.9) 0.50
aValues are expressed as No. (%).
the nasal mask over the face anatomical mask, the reason
for the difference between the results of our study and the
above-mentioned study was the difference in the mask, the
difference in the method studied and recruiting individu-
als to control and the lack of replacement groups studied
in Liang et al.’s study (11). In other words, in Liang’s study, it
was better to put a nasal mask on one group and a mouth-
nose mask on the other group from the beginning.
One of the reasons for the difference between the re-
sults of the present study and other similar studies is
the lack of examination and matching for BMI in the two
groups. However, considering that the average weight of
the two groups of children was not different, this assump-
tion can be somewhat trusted. In addition, given that our
study compared the two methods in children, we can ex-
plain the difference in results with other similar studies.
There are two main points in using a mask: complete
sealing between the face and the mask with no gas leakage
and the openness of the patient’s airways, which should
always be checked. The quality of sealing in spontaneous
ventilation is determined by the filling and movements of
the mask storage bag. Gas leaks usually occur around the
nose and cheeks. It should be noted that there is no need to
seal when using a nasal mask. On the other hand, the symp-
toms of airway obstruction depend on the location and ex-
tent of the obstruction and whether the positive pressure
method is used or breathing is done spontaneously. The
most important clinical sign is airway obstruction. Snor-
ing occurs in the supraglottic occlusion, and the tail stri-
dor occurs in the gluteal occlusion, a classical sign of air-
way obstruction in spontaneous respiration (19,20).
One of the limitations of the present study is the lack of
examination and matching for body mass index in the two
groups, which makes it difficult to conclude. It is recom-
mended to conduct a comparative study of hemodynamic
changes in these two methods because it has been proven
that hypotension and the subsequent increase in heart
rate are the side effects of anesthetic induction drugs, es-
pecially thiopental and opioids (21,22). However, why
was there a significant difference between our two study
groups? Whether this difference was random or whether
the nasal mask caused a further drop in blood pressure is a
subject that should be considered in future studies.
5.1. Conclusions
Since the nasal mask does not create positive pressure
on the tongue and soft palate and the difficulty of the nasal
Anesth Pain Med. 2022; 12(3):e123205. 5
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Aghadavoudi O et al.
airway, a collapse does not occur with this method. Hence,
nasal masks can be used as an alternative in children due
to the anatomical features of the airways and the possibil-
ity of further airway obstruction, and in other people in
whom sealing is difficult, and the possibility of preparing
a face mask is low. The results of the present study showed
that in terms of ventilation parameters, both methods had
similar results and performance except for EtCO2, which
was significantly higher in the second minute after ventila-
tion in the nasal mask group than in the face mask group;
of course, both were in the normal range. Another differ-
ence between the two methods was people’s blood pres-
sure after ventilation; however, the blood pressure param-
eters were within the normal range.
Acknowledgments
This research was supported by the Medical Faculty Re-
search Council of Isfahan University of Medical Sciences.
Footnotes
Authors’ Contribution: O. A. and D. B.: Conceptual-
ization, data collection, investigation, writing the origi-
nal draft, review, and editing. A. SH.: Conceptualization,
methodology, project administration, supervision, writ-
ing the original draft, review, and editing. A. SH. and O.
A.: Conceptualization, methodology, writing, review, and
editing.
Clinical Trial Registration Code: NCT05018468, link:
clinicaltrials.gov/ct2/show/NCT05018468.
Conflict of Interests: The authors declare they have no
conflict of interest.
Data Reproducibility: The data that support the find-
ings of this study are available on request from the corre-
sponding author, A. SH. (Amir Shafa). The data are not pub-
licly available because they contain information that could
compromise the privacy of research participants.
Ethical Approval: The current study protocol was ap-
proved by the Ethics Committee of Isfahan University of
Medical Sciences (ethical code: IR.MUI.REC.1395.3.424).
Funding/Support: The authors received no specific fund-
ing for this work.
Informed Consent: Inform consent was obtained from
patients’ parents.
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