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 Table of Contents  
Year : 2023  |  Volume : 10  |  Issue : 3  |  Page : 101-106

How to choose between high-flow nasal cannula, continuous positive airway pressure, and bilevel positive airway pressure in children with acute respiratory illness

1 Department of Pediatric Critical Care, Rainbow Children's Hospital, Chennai, Tamil Nadu, India
2 Department of Pediatric Intensive Care, Manipal Hospital, Banglore, Karnataka, India
3 Paediatric Critical Care Unit, Sidra Medicine, Doha, Qatar

Date of Submission19-Apr-2023
Date of Decision03-May-2023
Date of Acceptance07-May-2023
Date of Web Publication19-May-2023

Correspondence Address:
Dr. Manu Sundaram
Paediatric Critical Care Unit, Sidra Medicine, Doha
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jpcc.jpcc_33_23

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In pediatric patients with acute respiratory illnesses, the widespread availability of heated humidified high-flow nasal cannula (HHHFNC) devices, ease of use, and increased compliance have increased their use in conditions such as pneumonia, acute respiratory failure, asthma, and acute respiratory distress syndrome. Due to the patient comfort and ease of use of HHHFNC, there are widely used. Similarly, the use of NIV is increasing due to the availability of better interfaces and non-invasive ventilators (NIV) for use in infants The conundrum has been regarding the generation of positive end-expiratory pressure in these open circuits of the HHHFNC devices versus the pressures delivered by the closed circuits in the NIV devices. This article reviewed the latest literature based on the clinical conditions and the rationale for selecting respiratory support in common acute respiratory illnesses.

Keywords: Bilevel positive airway pressure, continuous positive airway pressure, high-flow nasal cannula

How to cite this article:
Narayanan R K, Ashwath Ram R N, Sundaram M. How to choose between high-flow nasal cannula, continuous positive airway pressure, and bilevel positive airway pressure in children with acute respiratory illness. J Pediatr Crit Care 2023;10:101-6

How to cite this URL:
Narayanan R K, Ashwath Ram R N, Sundaram M. How to choose between high-flow nasal cannula, continuous positive airway pressure, and bilevel positive airway pressure in children with acute respiratory illness. J Pediatr Crit Care [serial online] 2023 [cited 2023 Jun 2];10:101-6. Available from: http://www.jpcc.org.in/text.asp?2023/10/3/101/377435

  Introduction Top

Although many patients have been managed on these devices, there is an increase in the incidence of delayed intubation from prolonged trials of HHHFNC.[1] Most of the high quality evidence was from the randomized controlled trials of HHHFNC in bronchiolitis. With better interfaces, noninvasive ventilation (NIV) has increased, but large randomized controlled trials are currently lacking.[2],[3],[4],[5] There is increasing usage of heated humidified high-flow nasal cannula (HHHFNC) and noninvasive ventilation (NIV) modalities such as continuous positive airway pressure (CPAP) and bilevel positive airway pressure (BiPAP) among children with acute respiratory failure in several pediatric intensive care units (PICU) in India.[6],[7] HHHFNC, NIV-CPAP, and BiPAP have been interchangeably used in various clinical conditions, including acute bronchiolitis, pneumonia, bronchial asthma, and pulmonary edema. Recently, HHHFNC has been used more among children with acute respiratory distress in Indian settings than NIV due to its convenience and ease of nursing care. In a multicenter observational study, Morris et al. observed that initiating NIV as unplanned respiratory support before invasive ventilation significantly reduced mortality, ventilation-free days, and length of PICU stay.[8] However, increased mortality was observed when the impact of preintubation noninvasive respiratory support (HHHFNC and NIV) was studied in children with pediatric respiratory distress syndrome. Hence, choosing the right patient and appropriate noninvasive respiratory support is essential to improve outcomes. This article discusses how to select the proper respiratory support in children with various pathological lung conditions with case-based discussions.

  Contraindications For Noninvasive Respiratory Support Top

One should avoid considering noninvasive respiratory support in children without contraindications. The neurology, airway, breathing, circulation (NABC) acronym provides a structured approach to check the different contraindications[9] [Table 1].
Table 1: Noninvasive ventilation contraindications

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  Case 1: Acute Pneumonia/Respiratory Failure/Acute Respiratory Distress Syndrome Top

A 6-month-old child presented with fever, cough for 3 days, and rapid breathing for 1 day. On examination, respiratory rate was 78/min, intercostal and subcostal retractions were present, bilateral crepitations on auscultation, and room air saturation 78% (on a nonrebreathing mask –95%). The chest X-ray (CXR) showed bilateral consolidation [Figure 1]. He was hemodynamically stable. The infant was shifted to PICU for respiratory support. What respiratory support would you offer?
Figure 1: The CXR showing bilateral consolidation. CXR: Chest X-ray

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Answer: NIV (BiPAP/S/T mode).


The infant has a parenchymal lung disease leading to type 1 respiratory failure. The probable pathological mechanism causing hypoxia is reduced compliance and functional residual capacity, increased dead space, shunt fraction, and extravascular lung water. This results in low PaO2 with usually typical PaCO2. In a patient with severe respiratory distress, recurrent alveoli collapse can result in atelectotrauma and subsequent pediatric self-inflicted lung injury (p-SILI).[10] Early initiation of bilevel ventilation and optimal positive end-expiratory pressure (PEEP) to achieve tidal volumes of 6–8 ml/kg reduced the risk of p-SILI. Chisti et al., in their landmark paper, have shown an increase in the mortality of patients on low-flow oxygen therapy compared to bubble CPAP.[11] In this patient with pneumonia, the success rate for NIV was 80%.[12]

In these same patients, if the FiO2 keeps increasing, this patient would be on the spectrum for pediatric acute respiratory distress syndrome (pARDS).[9] The success rates for NIV in pARDS are lower than 50%. Early intubation without an NIV trial should be considered in children with severe pARDS (P/F ratio <100; S/F ratio <150). NIV trial can be offered in moderate acute respiratory distress syndrome (ARDS) (P/F ratio <200, S/F ratio 150–235), where the response is judged as the reduction in heart rate, respiratory rate, work of breathing, and FiO2 after a trial of NIV for 2–6 h. Consider intubation and invasive ventilation in these patients with moderate to severe ARDS [Figure 2]. One should be very cautious to avoid overdistention of the lung, which may lead to p-SILI while using NIV.[13]
Figure 2: Choosing respiratory support in acute hypoxic respiratory failure[9]

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HHHFNC has little effect on lung recruitment. Although some benefits can be obtained by its impact on decreasing extra thoracic dead space and modest positive pharyngeal pressure of about 4 cm H2O during expiration, it does not recruit the lung and improve functional residual capacity.[14] It can be used to preoxygenate the child before invasive mechanical ventilation (as it can reliable deliver fixed FiO2). Nonetheless, the quality of oxygenation, higher comfort, and the results of the FLORALI trial in adults with acute hypoxic respiratory failure have raised the role of HHHFNC or the harmful effects of overdistention of the lungs due to NIV.[15] In the FIRST-ABC Step-Up randomized trial by Ramnarayan et al., which compared HHFNC and NIV as first-line respiratory support in acute hypoxic respiratory failure, HHHFNC was found noninferior to NIV when the time to liberation from respiratory support as outcome parameter was considered. However, 50% of the cohort consisted of acute bronchiolitis, and fewer (<10%) had pneumonia.[16] Hence, the utility of HHHFNC as an alternative to NIV-CPAP requires further studies. Till then, it is better to limit its use to mild ARDS with low work of breathing or low risk of p-SILI.

Studies have shown that the success rate for NIV is higher in patients with a neuromuscular condition who have respiratory failure. In type 2 respiratory failure, the success rate is 85%. This is typical for patients with various muscular dystrophies and myopathy to have respiratory failure and then require NIV for acute on chronic respiratory failure.

  Case 2: Acute Bronchiolitis Top

A 3-month-old infant with no significant perinatal history presented with fever, cold for 3 days, and breathing difficulty for 1 day. Examination revealed intercostal and subcostal retractions and bilateral wheeze with crepitation. Room air saturation was 88%. On nasal oxygen therapy, saturation improved to 95%; the infant was nebulized with 3% saline and adrenaline. Wheeze reduced, but distress persisted. The CXR showed bilateral hyperinflation with streaky opacities with segmental atelectasis [Figure 3]. What is the ideal respiratory support for this child?
Figure 3: Bilateral hyperinflation with multiple segmental atelectasis

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Answer: Heated, humidified high-flow nasal cannula is appropriate respiratory support for this child.


The high-flow nasal cannula (HFNC) has most often been evaluated in populations with acute viral bronchiolitis, with several studies comparing the efficacy and tolerance of HHHFNC with various CPAP systems. A recent meta-analysis (15 studies, 1127 patients) showed that the prophylactic use of HHHFNC did not reduce PICU admission in the study done by Milési et al. HFNC has a higher failure rate compared to nasal CPAP (nCPAP).[3] This crossover study demonstrated that patients who failed on HHHFNC responded to rescue therapy with CPAP and vice versa.

Assess the severity of distress and oxygenation in the child with acute bronchiolitis; if the infant has SpO2 <90% on nasal oxygen, S/F ratio <200 on HHHFNC, decreased air entry bilaterally, depressed sensorium, and severe retractions, then consider starting nCPAP/BiPAP. If the above findings are not observed, HHHFNC is the preferred respiratory support in moderate bronchiolitis (SpO2 >90% on nasal oxygen, mild-to-moderate respiratory distress, agitated and alert sensorium, and regular air entry). HHHFNC of up to 2 ml/kg/min and FiO2 of 50% can be initiated in pediatric wards, and it is safe in various studies. Apnea is the only contraindication to noninvasive respiratory support in bronchiolitis, which requires intubation and mechanical ventilation [Table 2].
Table 2: Preferred modes for noninvasive respiratory support

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If the patient has deterioration on the HHHFNC therapy and a collapse consolidation is noted on the CXR, then the patient would benefit from a CPAP as it delivers a measurable PEEP. Therefore, reserving HHHFNC use for moderate bronchiolitis and NIV/CPAP for severe bronchiolitis seems reasonable.

  Case 3: Bronchial Asthma Top

A 5-year-old child presented to the emergency room with acute onset breathing difficulty. He was drowsy with decreased bilateral air entry, wheeze on expiration, prolonged expiration, and room air SpO2-85% and 93% on venturi face mask oxygen (FiO2-60%). He was given nebulization with beta-agonists, intravenous steroids, and intravenous magnesium sulfate. The CXR had bilateral hyperinflation [Figure 4]. There was no response, and his SpO2 on 60% FiO2 decreased to 88%. Arterial blood gas revealed hypercapnic metabolic acidosis (pH – 7.23, pO2-62, pCO2-78, HCO3-26). What is the optimal initial respiratory support?
Figure 4: Bilateral hyperinflation in the CXR. CXR: Chest X-ray

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Answer: Noninvasive BiPAP.


The child has Type 2-hypercapnic respiratory failure caused due to hypoventilation resulting from lower airway obstruction. Asthma causes dynamic airway obstruction leading to air trapping and auto-PEEP. HHHFNC and NIV-CPAP can deliver fixed FiO2; however, it might not be helpful to overcome the auto-PEEP effectively and increase minute ventilation, thereby causing carbon dioxide washout. NIV-BiPAP helps overcome dynamic airway inflation to decrease respiratory muscle overload, increase minute ventilation, and improve gas exchange. The NIV acts as a bridge to support the work of breathing while the bronchodilator therapy is working, with continuous inhaled bronchodilators and steroids. The success rate for NIV in severe asthma has been quoted as about 80%.[12],[17],[18] de Miguel-Díez et al. observed that NIV decreased the length of PICU stay in children with acute asthma exacerbation.[19] Contraindications include an unconscious child with compromised airways and hemodynamic instability with imminent cardiorespiratory arrest (gasping respiration, cyanosis, and bradycardia).

HHHFNC has also been attempted in bronchial asthma and observed to be well tolerated. Heated and humidified gas flow reduces the burden on inspiratory muscle related to auto-PEEP and limits bronchoconstriction induced by cold, dry gas. In an observational study, the failure rate was higher with HHHFNC than with NIV.[20] The role of HHHFNC is limited to moderate asthma, and NIV is preferable in severe asthma.[20] Another caution that must be considered while using HHHFNC is the delivery of inhalational bronchodilator medications. The dose of bronchodilator delivered varies from 0.5% to 25% of the administered dose.[20] The highest dose delivery is observed when the flow is reduced, and the aerosol is delivered upstream of the humidifier with an ultrasonic nebulizer.[21],[22]

  Case 4: Cardiogenic Pulmonary Edema Top

An 8-month-old infant presented with a low-grade fever and cold for 3 days, irritability, and breathing difficulty for the past 6 h. On examination, there was tachycardia, tachypnea with retractions, bilateral crepitations on lung auscultation, gallop on cardiac auscultation and hepatomegaly, and room air saturation 88% (98% on a nonrebreathing mask), and the CXR showed cardiomegaly with pulmonary edema. His peripheries were cold, his blood pressure was at the 5th centile for age and height, and he had feeble peripheral pulses. He was started on epinephrine infusion at 0.05 μg/kg/min. How to choose the ideal respiratory support?

Answer: Noninvasive positive pressure ventilation (NIPPV).


The index child has cardiogenic pulmonary edema (CPE) due to myocarditis. This is a low cardiac output state with increased extravascular lung water and alveolar flooding. Respiratory distress in a baby with cardiac failure can worsen organ perfusion (as 50% of the cardiac output is used to fulfill the metabolic demands of the respiratory muscles). Increased negative pleural pressures generated due to respiratory distress can increase the afterload of the left ventricle, thereby leading to a further decrease in cardiac output.[23]

NIV (CPAP/BiPAP or NIPPV) is most helpful in lung parenchymal disease. It is useful in obstructive airway diseases (bronchiolitis) as it reduces the transmural pressure swing and maintains airway patency. Reducing transthoracic pressure swinging reduces left ventricular afterload and improves stroke volume. With decreasing work of breathing, the cardiac output is better distributed and reduces lactic acidosis. It can prevent intubation and mechanical ventilation complications, decrease the need for these interventions, and prevent extubation failure. For all children having heart disease with increased work breathing and lung parenchymal problems, we can start NIPPV considering altered lung mechanics as described above. The minimum recommended expiratory positive airway pressure (EPAP)/PEEP is 4–5 cm H2O. EPAP ≥5 cm is associated with an added benefit above FiO2. Consider NIPPV or NIV BiPAP if there is associated hypercarbia (pCO2 >50 cm H2O).

HHHFNC, compared to conventional oxygen therapy devices, is associated with better oxygenation (PaO2/FiO2 ratio), reducing the need for NIPPV but not intubation in postoperative cardiac children. For clinical practice, HFNC is better tolerated and seems feasible in most populations currently managed with NIV and CPAP. HHHFNC must be used early, in mild-to-moderate respiratory distress and minimal pulmonary opacity, normal perfusion, and P/F ratio >200. Since our index child has low cardiac output with impaired perfusion, HHHFNC is not ideal in the above setting.

In CPE, in conditions of fluid overload like nephrotic syndrome and oncology patients on hyperhydration regime, the success rate for NIV with diuretic therapy is around 95%.

  Conclusion Top

The Indications, contraindications, equipment, modes, analysis of failure/ success, and next steps (ICEMAN) acronym provides a structured approach to the initiation of NIV. The components are indications, contraindications, equipment, modes, analysis of failure/success, and next steps.

Choosing the proper respiratory support depends on the pathology behind the respiratory difficulty. Contraindications to noninvasive respiratory support should be identified before initiation. HHHFNC is better than low-flow oxygen therapy and noninferior to NIV-CPAP in children with mild-moderate respiratory disease. In severe respiratory distress, NIV-BiPAP/NIPPV should be initiated. Monitoring for the failure of NIV and early intubation is the key to the optimal outcome.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient (s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Kang BJ, Koh Y, Lim CM, Huh JW, Baek S, Han M, et al. Failure of high-flow nasal cannula therapy may delay intubation and increase mortality. Intensive Care Med 2015;41:623-32.  Back to cited text no. 1
Schibler A, Pham TM, Dunster KR, Foster K, Barlow A, Gibbons K, et al. Reduced intubation rates for infants after introduction of high-flow nasal prong oxygen delivery. Intensive Care Med 2011;37:847-52.  Back to cited text no. 2
Milési C, Essouri S, Pouyau R, Liet JM, Afanetti M, Portefaix A, et al. High flow nasal cannula (HFNC) versus nasal continuous positive airway pressure (nCPAP) for the initial respiratory management of acute viral bronchiolitis in young infants: A multicenter randomized controlled trial (TRAMONTANE study). Intensive Care Med 2017;43:209-16.  Back to cited text no. 3
Milési C, Pierre AF, Deho A, Pouyau R, Liet JM, Guillot C, et al. A multicenter randomized controlled trial of a 3-L/kg/min versus 2-L/kg/min high-flow nasal cannula flow rate in young infants with severe viral bronchiolitis (TRAMONTANE 2). Intensive Care Med 2018;44:1870-8.  Back to cited text no. 4
Franklin D, Babl FE, George S, Oakley E, Borland ML, Neutze J, et al. Effect of early high-flow nasal oxygen versus standard oxygen therapy on length of hospital stay in hospitalized children with acute hypoxemic respiratory failure: The PARIS-2 randomized clinical trial. JAMA 2023;329:224-34.  Back to cited text no. 5
Sadasivam K, Ramachandran B. A survey of humidified high-flow nasal cannula usage in Indian pediatric intensive care units. Indian J Crit Care Med 2020;24:996-8.  Back to cited text no. 6
Punn D, Gill KS, Bhargava S, Pooni PA. Clinical profile and outcome of children requiring noninvasive ventilation (NIV). Indian J Pediatr 2022;89:466-72.  Back to cited text no. 7
Morris JV, Ramnarayan P, Parslow RC, Fleming SJ. Outcomes for children receiving noninvasive ventilation as the first-line mode of mechanical ventilation at intensive care admission: A propensity score-matched cohort study. Crit Care Med 2017;45:1045-53.  Back to cited text no. 8
Villanueva AM, Orive JP, Cuscó MG, Blokpoel R, Òdena MP, Rimensberger P. Handbook of Paediatric and Neonatal Mechanical Ventilation. 2021, 2nd edition. e-book. ISBN: 978-84-124534-0-9.  Back to cited text no. 9
Carteaux G, Parfait M, Combet M, Haudebourg AF, Tuffet S, Mekontso Dessap A. Patient-self inflicted lung injury: A practical review. J Clin Med 2021;10:2738.  Back to cited text no. 10
Chisti MJ, Salam MA, Smith JH, Ahmed T, Pietroni MA, Shahunja KM, et al. Bubble continuous positive airway pressure for children with severe pneumonia and hypoxaemia in Bangladesh: An open, randomised controlled trial. Lancet 2015;386:1057-65.  Back to cited text no. 11
Mayordomo-Colunga J, Medina A, Rey C, Díaz JJ, Concha A, Los Arcos M, et al. Predictive factors of noninvasive ventilation failure in critically ill children: A prospective epidemiological study. Intensive Care Med 2009;35:527-36.  Back to cited text no. 12
Bellani G, Laffey JG, Pham T, Madotto F, Fan E, Brochard L, et al. Noninvasive ventilation of patients with acute respiratory distress syndrome. Insights from the LUNG SAFE study. Am J Respir Crit Care Med 2017;195:67-77.  Back to cited text no. 13
Milési C, Baleine J, Matecki S, Durand S, Combes C, Novais AR, et al. Is treatment with a high flow nasal cannula effective in acute viral bronchiolitis? A physiologic study. Intensive Care Med 2013;39:1088-94.  Back to cited text no. 14
Jentzer J, Dezfulian C, Emlet L. High-flow oxygen through nasal cannula in acute hypoxemic respiratory failure: The FLORALI study. F1000 Res 2016;5:41.  Back to cited text no. 15
Ramnarayan P, Richards-Belle A, Drikite L, Saull M, Orzechowska I, Darnell R, et al. Effect of high-flow nasal cannula therapy versus continuous positive airway pressure therapy on liberation from respiratory support in acutely ill children admitted to pediatric critical care units: A randomized clinical trial. JAMA 2022;328:162-72.  Back to cited text no. 16
Thill PJ, McGuire JK, Baden HP, Green TP, Checchia PA. Noninvasive positive-pressure ventilation in children with lower airway obstruction. Pediatr Crit Care Med 2004;5:337-42.  Back to cited text no. 17
Teague W. Noninvasive positive pressure ventilation (NPPV) in critically ill children with status asthmaticus. Am J Respir Crit Care Med 1998;157:542.  Back to cited text no. 18
de Miguel-Díez J, Jiménez-García R, Hernández-Barrera V, López de Andrés A, Villa-Asensi JR, Plaza V, et al. National trends in hospital admissions for asthma exacerbations among pediatric and young adult population in Spain (2002-2010). Respir Med 2014;108:983-91.  Back to cited text no. 19
Pilar J, Modesto I Alapont V, Lopez-Fernandez YM, Lopez-Macias O, Garcia-Urabayen D, Amores-Hernandez I. High-flow nasal cannula therapy versus non-invasive ventilation in children with severe acute asthma exacerbation: An observational cohort study. Med Intensiva 2017;41:418-24.  Back to cited text no. 20
Perry SA, Kesser KC, Geller DE, Selhorst DM, Rendle JK, Hertzog JH. Influences of cannula size and flow rate on aerosol drug delivery through the vapotherm humidified high-flow nasal cannula system. Pediatr Crit Care Med 2013;14:e250-6.  Back to cited text no. 21
Li J, Gong L, Ari A, Fink JB. Decrease the flow setting to improve trans-nasal pulmonary aerosol delivery via “high-flow nasal cannula” to infants and toddlers. Pediatr Pulmonol 2019;54:914-21.  Back to cited text no. 22
Gupta P, Kuperstock JE, Hashmi S, Arnolde V, Gossett JM, Prodhan P, et al. Efficacy and predictors of success of noninvasive ventilation for prevention of extubation failure in critically ill children with heart disease. Pediatr Cardiol 2013;34:964-77.  Back to cited text no. 23


  [Figure 1], [Figure 2], [Figure 3], [Figure 4]

  [Table 1], [Table 2]


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