A Critical Review of Oxygen Flow Types and RCT: Bronchiolitis

This report presents a critical appraisal of a research paper by Kepreotes et al. (2017), utilizing the CASP tool to evaluate a randomized controlled trial (RCT) comparing high-flow warm humidified oxygen (HFWHO) and standard low-flow nasal cannula oxygen for treating moderate bronchiolitis in children. The analysis meticulously examines the validity of the trial's results, assessing randomization, patient accounting, blinding, and group similarity. It delves into the treatment effects, including the magnitude and precision of outcomes such as oxygen weaning time and treatment failure rates. Furthermore, the report considers the applicability of the results to local populations, evaluating the clinical importance of outcomes and the balance between benefits, harms, and costs. The study found no significant difference in median oxygen weaning time between the two oxygen delivery methods, although HFWHO showed promise as a rescue tool, prompting the need for further research to optimize its clinical application. The report is available on Desklib, a platform offering AI-based study tools for students.

Running head: A CRITICAL REVIEW OF DIFFERENT TYPES OF OXYGEN FLOWS
A CRITICAL REVIEW OF DIFFERENT TYPES OF OXYGEN FLOWS AND
RANDOMISED CONTROLLED TRIAL
Name of the Student:
Name of the University:
Author Note:

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Executive Summary
In this article a research, paper by Kepreotes et al., (2017) is being critically appraised using
the CASP tool and guidelines. The difference of effect between standard oxygen therapy and
HFWHO has been reviewed by randomised controlled trial. However, no significant
difference of median oxygen weaning off time was found between the two oxygen delivery
types. Although HFWHO proved to be a rescue tool for children who are in the brink of
being admitted to the ICU. Effectiveness of HFWHO as a rescue tool should be researched
further for better implications in near future.

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Table of Contents
1. Introduction............................................................................................................................3
2. Discussion..............................................................................................................................3
2.1. Section A: Are the results of the trial valid?...................................................................3
2.1.1. Did the trial address a clearly focused issue?...........................................................3
2.1.2. Was the assignment of patients to treatments randomised?.....................................3
2.1.3. Were all of the patients who entered the trial properly accounted for at its
conclusion?.........................................................................................................................4
2.1.4. Were patients, health workers and study personnel ‘blind’ to treatment?...............4
2.1.5. Were the groups similar at the start of the trial........................................................5
2.1.6. Aside from the experimental intervention, were the groups treated equally?..........5
2.2. Section B: What are the results?.....................................................................................5
2.2.1. How large was the treatment effect?........................................................................5
2.2.2. How precise was the estimate of the treatment effect?............................................6
2.3. Section C: Will the results help locally?.........................................................................6
2.3.1. Can the results be applied to the local population, or in your context?...................6
2.3.2. Were all clinically important outcomes considered?...............................................7
2.3.3. Are the benefits worth the harms and costs?............................................................7
3. Conclusion..............................................................................................................................7
References..................................................................................................................................8

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1. Introduction
Bronchiolitis is a very common illness found in the respiratory tracts. The bronchioles
and the parts of lungs are affected by the infection in adults and children (Yon et al., 2018).
Inflammation, swelling and excessive mucus production occurs in the bronchioles due to the
infection which require the supply of oxygen flow (Mayfield et al., 2014). In this article the
research paper named “High-flow warm humidified oxygen versus standard low-flow nasal
cannula oxygen for moderate bronchiolitis (HFWHO RCT): an open, phase 4, randomised
controlled trial” by Kepreotes et al., (2017) is being critically appraised using the CASP tool.
2. Discussion
2.1. Section A: Are the results of the trial valid?
2.1.1. Did the trial address a clearly focused issue?
Yes, the trial has addressed the issue clearly in the research.
The study focuses on the effectiveness of high flow warm humidified oxygen and low flow
nasal cannula oxygen flow for children aged less than two years old with moderate level of
bronchiolitis in this article. The effectiveness of the HFWHO and the standard oxygen flow
were compared based on their effectiveness and oxygen weaning off time in the children
under trial (Kepreotes et al., 2017).
2.1.2. Was the assignment of patients to treatments randomised?
Yes, the assignment and allocation of patients to two types of treatment was
conducted randomly.
Random allocation was done on 1:1 basis after attaining mutual consent from the medical
unit and emergency department of the hospital. 101 children were allocated in the standard
therapy arm and 101 children were intervened under HFWHO arm. It was done by using size

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four block. The children were segregated based on their age. One category was extremely
premature who were aged less than 28 weeks. The second one was categorised as premature
who were aged more than 28 weeks but less than 37 weeks. The third category was aged
more than 37 weeks. The three (Kepreotes et al., 2017).
2.1.3. Were all of the patients who entered the trial properly accounted for at its
conclusion?
Yes, all the participants in the trial were properly accounted for at its conclusion.
Some of the children under standard therapy and HFWHO sometimes experienced treatment
failure and adverse events. Though the events were few and far between and children under
HFWHO experienced lesser treatment failure. Bronchiolitis is a common phenomenon in
infants and aid of oxygen flow in the ICU is necessary in the critical situations (Øymar,
Skjerven & Mikalsen, 2014). When adverse incidents or treatment failure occurred, the
children were transferred to the ICU immediately (Ojha, Gridley & Dorling, 2013). All the
children who were under the randomised controlled trial were safe in the end, no child was
withdrawn from the study and no serious adverse event occurred (Kepreotes et al., 2017).
2.1.4. Were patients, health workers and study personnel ‘blind’ to treatment?
No the health workers and study personnel were not ‘blind’ to treatment, as masking
was not possible during allocation while patients were children aged less than two years so
understanding the clinical difference was not possible for them.
Allocation done by the lead investigator was properly sealed in envelops but at the time of
delivering treatment the concealing of treatment procedures was not possible (Kepreotes et
al., 2017). Difference in the two modes of oxygen delivery was easily distinguishable so the
stakeholders involved in the treatment were not ‘blind’ to the trial at all.

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2.1.5. Were the groups similar at the start of the trial
Yes, groups were similar when the trial began.
Total sample size of the study conducted was consisting of 202 children aged less than 2
years suffering from moderate level Bronchiolitis. They were randomly allocated by the lead
investigator in the ratio of 1:1. 101 children were allocated to the standard therapy arm while
rest of the 101 children were assigned to the experimental group under HFWHO (Kepreotes
et al., 2017). So the sample size was equal at the start of the trial.
2.1.6. Aside from the experimental intervention, were the groups treated equally?
Yes except for the intervention process, the two groups were treated equally.
The treatment of standard therapy and HFWHO had difference in the oxygen supply quantity
due to the intervention except that treatment procedure was similar for both the oxygen
delivery type (McCullough, 2017). Both of the oxygen supply arms started at maximum
therapy and continued for three hours. In the first hour nil by mouth nursing method was used
for all the children. Hearth rate and SpO2 were checked for all the participating children in
regular intervals (Jones et al., 2016). Nasal hygiene was taken care of. Nasopharyngeal
extract was collected before starting the oxygen supply of all the children. So except for the
difference in oxygen supply the two groups were treated equally (Kepreotes et al., 2017).
2.2. Section B: What are the results?
2.2.1. How large was the treatment effect?
There was no significant treatment effect, as the results from the oxygen delivery
procedures did not have substantial difference.

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Median time for Oxygen weaning off was 20 hours (95% CI 17-34) in HFWHO treatment
arm while it was 24 h (95% CI 18–28) in standard treatment arm (Kepreotes et al., 2017).
Based on this outcome in can be inferred that no significant treatment effect was reflected
(Frat et al., 2015). However HFWHO reduced the number of treatment failure and worked as
a rescue therapy for the children suffering from moderate bronchiolitis.
2.2.2. How precise was the estimate of the treatment effect?
The estimate of the treatment effect was precise as it was measured based on the
oxygen weaning off time and HFWHO was more effective than standard therapy in reducing
treatment failure.
Effect of HFWHO was statistically and clinically proved in terms of reducing the number of
treatment failure and delaying the time for clinical failure during the trial. Significance
threshold were adjusted to 0.005 during observation of these outcomes (Kepreotes et al.,
2017). Though there was no significant difference in the oxygen weaning time of HFWHO
and standard therapy.
2.3. Section C: Will the results help locally?
2.3.1. Can the results be applied to the local population, or in your context?
Yes, the results can be applied to the local population.
The result of the randomised controlled trial does not reflect any significant difference in the
oxygen weaning off time of HFWHO and standard therapy (Kepreotes et al., 2017). Though
usage of HFWHO prevented ICU admission of the children, reduced the number of treatment
failure and delayed the time (Beggs et al., 2014). So HFWHO can be used as a rescue therapy
for children who are suffering from moderate bronchiolitis. So HFWHO can be used to
reduce the clinical cost by curtailing the number of ICU admission.

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2.3.2. Were all clinically important outcomes considered?
Yes, all clinically important outcomes were considered.
The study considered all the clinically important outcomes as the participants in the study
were children aged less than two years. In both the treatment arms, safety of the children was
the priority and they were admitted to the ICU in case of any treatment failure or adverse
events (Kepreotes et al., 2017). No fatal adverse event occurred during the randomised
control trial.
2.3.3. Are the benefits worth the harms and costs?
Yes the benefits worth the harm and cost.
No harm was done to the children during the study period. After the study from the data
analysis, it was found that though there is no significant difference in the median oxygen
weaning off time between HFWHO and standard therapy (Kepreotes et al., 2017). Any
adverse events during the interventions were taken care of immediately. Although HFWHO
proved to be a rescue tool for the children with moderate bronchiolitis which reduces the rate
of ICU admission and the treatment failure (Parke & McGuinness, 2013).
3. Conclusion
From the study, it was proved that there was no relevant difference of oxygen
weaning off time between HFWHO and standard therapy though HFWHO reduces treatment
failure and adverse patient related outcomes. Further research should be conducted to find out
the role of HFWHO as a rescue tool and optimum clinical setting for this oxygen supply
method.

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References
Beggs, S., Wong, Z. H., Kaul, S., Ogden, K. J., & Walters, J. A. (2014). High‐flow nasal
cannula therapy for infants with bronchiolitis. Cochrane Database of Systematic
Reviews, (1).
Frat, J. P., Thille, A. W., Mercat, A., Girault, C., Ragot, S., Perbet, S., ... & Devaquet, J.
(2015). High-flow oxygen through nasal cannula in acute hypoxemic respiratory
failure. New England Journal of Medicine, 372(23), 2185-2196.
Jones, P. G., Kamona, S., Doran, O., Sawtell, F., & Wilsher, M. (2016). Randomized
controlled trial of humidified high-flow nasal oxygen for acute respiratory distress in
the emergency department: the HOT-ER study. Respiratory care, 61(3), 291-299.
Kepreotes, E., Whitehead, B., Attia, J., Oldmeadow, C., Collison, A., Searles, A., ... &
Mattes, J. (2017). High-flow warm humidified oxygen versus standard low-flow nasal
cannula oxygen for moderate bronchiolitis (HFWHO RCT): an open, phase 4,
randomised controlled trial. The Lancet, 389(10072), 930-939.
Mayfield, S., Bogossian, F., O'Malley, L., & Schibler, A. (2014). High‐flow nasal cannula
oxygen therapy for infants with bronchiolitis: pilot study. Journal of paediatrics and
child health, 50(5), 373-378.
McCullough, C. (2017). High-flow warm humidified oxygen versus standard low-flow nasal
cannula for moderate bronchiolitis (HFWHO RCT): an open, phase 4, randomized
controlled trial: Kepreotes E, Whitehead B, Attia J et al. Lancet 2017; 389: 930.
Journal of Emergency Medicine, 53(1), 157.
Ojha, S., Gridley, E., & Dorling, J. (2013). Use of heated humidified high‐flow nasal cannula
oxygen in neonates: a UK wide survey. Acta paediatrica, 102(3), 249-253.

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Øymar, K., Skjerven, H. O., & Mikalsen, I. B. (2014). Acute bronchiolitis in infants, a
review. Scandinavian journal of trauma, resuscitation and emergency medicine,
22(1), 23.
Parke, R. L., & McGuinness, S. P. (2013). Pressures delivered by nasal high flow oxygen
during all phases of the respiratory cycle. Respiratory care, 58(10), 1621-1624.
Yon, D. K., Min, C. Y., Ha, E. K., Jee, H. M., Jung, Y. H., Lee, K. S., ... & Han, M. Y.
(2018). Clinical characteristics and genetic variation in respiratory syncytial virus
isolated from infants hospitalized due to acute bronchiolitis in Korea during winter
season 2016–2017. Allergy, Asthma & Respiratory Disease, 6(2), 110-115.