Nasal Cannula, CPAP, and High-Flow Nasal Cannula: Effect of Flow on Temperature, Humidity, Pressure, and Resistance

Chang, Gordon Y.; Cox, Cynthia; Shaffer, Thomas H.

doi:10.2345/0899-8205-45.1.69

Cited by 46 publications

(38 citation statements)

References 7 publications

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“…Studies conducted on lung models (artificial lungs and animal models) have shown that pressure delivery was directly proportional to HFNC flow and inversely affected by the amount of leak at the nasal interface. 15,16 Studies in infants have shown that the amount of pressure delivered to the pharynx, and possibly to the lungs, is associated with higher flows and lower infant weight. 1,[3][4][5] These human studies have also documented significant interpatient variability in measured pressures.…”

Section: Discussionmentioning

confidence: 99%

Association Between High-Flow Nasal Cannula and End-Expiratory Esophageal Pressures in Premature Infants

Iyer

Mhanna

2015

Respir Care

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BACKGROUND: High-flow nasal cannula (HFNC) is commonly being used to provide noninvasive respiratory support in newborn infants. Continuous distending pressure generated by these devices in preterm infants has not been elucidated. The aim of this work was to determine the association between HFNC flow in L/min and end-expiratory esophageal pressure in cm H 2 O in premature infants. METHODS: In a prospective observational study, end-expiratory esophageal pressure measurements were conducted in clinically stable premature infants who required HFNC. The end-expiratory esophageal pressure generated by the HFNC was measured by a regular feeding tube overlying the lower esophagus and connected to a pressure transducer. Each infant had different end-expiratory esophageal pressure measurements at different high flows ranging from 2 to 8 L/min. RESULTS: Nineteen premature infants were studied. Their birthweight (mean ؎ SD) was 904 ؎ 574 g, and gestational age was 26.6 ؎ 3.1 weeks. Overall, 93 end-expiratory esophageal pressure measurements were conducted. At the time of the end-expiratory esophageal pressure measurements, infants were 1,458 ؎ 828 g and 7.2 ؎ 4.8 weeks old. At HFNC flows ranging from 2 to 8 L/min, the corresponding esophageal pressures ranged from 2 to 15 cm H 2 O. There was a statistically significant association between esophageal pressures and flows. In a linear regression model with the end-expiratory esophageal pressure as the dependent variable and HFNC flow as the independent variable, there was a significant correlation between the 2 variables: end-expiratory esophageal pressure (cm H 2 O) ‫؍‬ 1.18 ؋ HFNC (L/min) (r 2 ‫؍‬ 0.95, P < .001). CONCLUSIONS: HFNC-associated end-expiratory esophageal pressure is measurable in premature infants. There is a significant association between flows and generated esophageal pressures. There is also variability in the amount of end-expiratory esophageal pressure generated. These observations should be kept in mind when using high HFNC flows in preterm infants.

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Section: Discussionmentioning

confidence: 99%

Association Between High-Flow Nasal Cannula and End-Expiratory Esophageal Pressures in Premature Infants

Iyer

Mhanna

2015

Respir Care

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“…The commercially available HFNC systems are open systems with leaks at the nose and mouth. These systems effectively humidify delivered gas [11,12] and provide a means to blend oxygen with air. A range of nasal prong sizes is available.…”

Section: Introductionmentioning

confidence: 99%

High-Flow Nasal Cannulae for Respiratory Support of Preterm Infants: A Review of the Evidence

Manley¹,

Dold

Davis³

et al. 2012

Neonatology

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Background: High-flow nasal cannulae (HFNC) are gaining in popularity as a form of non-invasive respiratory support for preterm infants in neonatal intensive care units around the world. They are proposed as an alternative to nasal continuous positive airway pressure (NCPAP) in a variety of clinical situations, including post-extubation support, primary therapy from birth and ‘weaning’ from NCPAP. Objectives: To present and discuss the available evidence for the use of HFNC in the preterm population. Methods: An internet-based literature search for relevant, original research articles (both randomised studies and not) on the use of HFNC in preterm infants was undertaken. Results: A total of 19 studies were included in the review. Distending pressure generated by HFNC in preterm infants increases with increasing flow rate and decreasing infant size and varies according to the amount of leak around the prongs. HFNC may be as effective as NCPAP at improving respiratory parameters such as tidal volume and work of breathing in preterm infants, but probably only at flow rates >2 litres/min. The efficacy and safety of HFNC in preterm infants remain to be determined. Conclusions: There is growing evidence of the feasibility of HFNC as an alternative to other forms of non-invasive ventilation in preterm infants. However, there remains uncertainty about the efficacy and safety of HFNC in this population. Until the results of larger randomised trials are known, widespread use of HFNC to treat preterm infants cannot be recommended.

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“…2 Chang et al reported that there is a linear relationship between pressure and flow, and the HFNC pressures are higher compared to continuous positive airway pressure (CPAP). 3 As a result of increased pressure with the airway, the risk of serious adverse effect including pneumothorax and pneumomediastinum is likely increased during HFNC. 4 Vézina et al stated that HFNC at a flow of 10 L/min was successfully used on a child with severe tracheomalacia.…”

Section: Dear Editormentioning

confidence: 99%

Can high flow nasal cannula be used in a pediatric patient with tracheomalacia?

Hatipoğlu

Esquinas

Özcengiz

2017

Pediatric Pulmonology

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We read with interest the article "Home high-flow nasal cannula as a treatment for severe tracheomalacia: A pediatric case report" by Vézina et al 1 The authors have successfully implemented high-flow nasal cannula (HFNC) oxygen therapy in children with tracheomalacia. However, we want to draw attention to some points about HFNC during clinical practice.Firstly HFNC in children is considered to be a generally safe choice among respiratory support modalities. However, the optimal gas flow during HFNC is unclear in children. The flow rate is generally used at 2-8 L/min. 2 Chang et al reported that there is a linear relationship between pressure and flow, and the HFNC pressures are higher compared to continuous positive airway pressure (CPAP). 3 As a result of increased pressure with the airway, the risk of serious adverse effect including pneumothorax and pneumomediastinum is likely increased during HFNC. 4 Vézina et al stated that HFNC at a flow of 10 L/min was successfully used on a child with severe tracheomalacia. 1 In this context, we would like to underline that patients must be closely monitored while on HFNC treatment at high flow rates to avoid complications.Secondly the authors said that the child used a nasojejunal pathway because of severe gastroesophageal reflux. 1 In an in vitro study it was reported that for safe and effective use of HFNC, an appropriate nasal prong to nares ratio is required. 5 In our opinion, the use of nasojejunal pathway for nutrition may impair suitable nasal prong to nares ratio, and consequently, the effectiveness of HFNC may decrease during treatment.Lastly the diagnosis of the child was tracheomalacia plus bronchomalacia. Thus, respiratory impairment likely results from a combination of the dynamic properties of the extrathoracic and the intrathoracic airway. 6 Hypoxemia as well as hypercapnia may be seen in these patients. In a recently published study by Testa et al, HFNC did not effectively reduce increased carbon dioxide levels. 7 Therefore, patients with tracheomalacia should be assessed both for hypoxemia and hypercapnia during HFNC treatment. CONFLICT OF INTERESTThe authors declare no conflict of interest. ORCIDZ. Hatipoğlu

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Nasal Cannula, CPAP, and High-Flow Nasal Cannula: Effect of Flow on Temperature, Humidity, Pressure, and Resistance

Abstract: Gas delivered by HFNC was more humid than NC and CPAP. However, the higher pressure and resistance delivered by the HFNC system may have clinical relevance, such as increased work of breathing, and warrants further in vivo studies.

Cited by 46 publications

References 7 publications

Association Between High-Flow Nasal Cannula and End-Expiratory Esophageal Pressures in Premature Infants

Association Between High-Flow Nasal Cannula and End-Expiratory Esophageal Pressures in Premature Infants

High-Flow Nasal Cannulae for Respiratory Support of Preterm Infants: A Review of the Evidence

Can high flow nasal cannula be used in a pediatric patient with tracheomalacia?

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