Despite the absence of clinical safety data, heated, humidified high-flow nasal cannula (HHFNC) therapy is increasingly being used as an alternative to positive-pressure ventilation in pediatrics. This use of HHFNC is “off label” because the US Food and Drug Administration’s approval for these devices was only for air humidification and not as a modality to provide positive distending pressure. For the first time we describe 3 cases who developed serious air leaks related to HHFNC therapy. The first child was a previously healthy 2-month-old male infant with respiratory syncytial virus bronchiolitis who developed a right pneumothorax on day 5 of his illness at 8 liters per minute (lpm). He subsequently required intubation and ventilation for 14 days. The second case involved an otherwise healthy 16-year-old boy with cerebral palsy who developed pneumomediastinum and died of its complications. He was receiving 20 lpm HHFNC therapy when he developed pneumomediastinum. The third case involved a 22-month-old, previously healthy boy who developed subdural hematoma secondary to abuse. He developed a right pneumothorax while receiving HHFNC at a flow of 6 lpm, requiring chest tube placement. These cases emphasize the need for extreme caution while using HHFNC for the off-label indication of providing positive distending pressure in children, especially at flows higher than the patient’s minute ventilation. A more detailed study to specifically look at the serious adverse events related to HHFNC is urgently needed.
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March 2013
Case Report|
March 01 2013
Serious Air Leak Syndrome Complicating High-Flow Nasal Cannula Therapy: A Report of 3 Cases
Satyanarayan Hegde, MD;
aDivision of Pediatric Pulmonary Medicine, Department of Pediatrics, University of Florida, Gainesville, Florida; and
Address correspondence to Satyanarayan (Satya) Hegde, MD, Department of Pediatrics, Division of Pediatric Pulmonary Medicine, University of Florida, PO Box 100296, 1600 SW Archer Rd, Ste D2-15, Gainesville, FL 32610. E-mail: hegdes@ufl.edu
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Parthak Prodhan, MBBS
Parthak Prodhan, MBBS
bDepartment of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas
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Address correspondence to Satyanarayan (Satya) Hegde, MD, Department of Pediatrics, Division of Pediatric Pulmonary Medicine, University of Florida, PO Box 100296, 1600 SW Archer Rd, Ste D2-15, Gainesville, FL 32610. E-mail: hegdes@ufl.edu
FINANCIAL DISCLOSURE: The authors have indicated they have no financial relationships relevant to this article to disclose.
Pediatrics (2013) 131 (3): e939–e944.
Article history
Accepted:
October 29 2012
Citation
Satyanarayan Hegde, Parthak Prodhan; Serious Air Leak Syndrome Complicating High-Flow Nasal Cannula Therapy: A Report of 3 Cases. Pediatrics March 2013; 131 (3): e939–e944. 10.1542/peds.2011-3767
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Comments
Serious Air Leak Syndrome Complicating High-Flow Nasal Cannula Therapy: A Report of 3 Cases
The report by Hegde and Prodham (Pediatrics 2013;131:e1-e6) regarding intra-thoracic air leak problems during heated humidified high flow nasal cannula (HHHFNC) raises several concerns. I concur wholeheartedly with their statement that off-label use of HHHFNC for "providing positive distending pressure" in children necessitates caution. I also agree detailed studies to evaluate risks associated with HHHFNC in children are needed. However, I have issues with the authors and the journal in publishing this report. First, the report describes only 3 patients with possible air leak associated complication. What is the denominator for HHHFNC use in this center? What are their rates for associated air leak with other modes of advanced non-invasive respiratory support? The authors suggest an urgent need for detailed evaluation of adverse events associated with HHHFNC, yet did not attempt to more aggressively assess this within their own center. Air leaks are not uncommon events in infants with respiratory disease on non-invasive support; why didn't the reviewers demand additional information to put this report in proper context? Second, the authors do not describe the approach to HHHFNC application. Were NC prongs tightly fitted to the nares; did they adhere to the recommended 50-80% ratio for NC to nares diameter? The importance of the NC:nares ratio, to allow free egress of the flow from the system and to minimize generation of inadvertent pressure, is well delineated by the recent study of Sivieri who showed limited and decreasing pressure delivery at ratios < 0.80.1 They correctly note the bench studies of Chang show extremely high pressures generated within the HHHFNC delivery system under conditions of complete airway occlusion.2 However, they neglect to state this study also measured extremely high pressures within delivery systems using conventional NC (18 cm H2O at 3 lpm) and CPAP (41 cm H2O at 8 lpm) under the same conditions. Again, this information should have been requested by reviewers.
An important question regarding HHHFNC relates to the mechanisms of action. These may be more related to the benefits of proper warmth and humidification, and to the insufflation effect on gas washout from nasopharyngeal dead space, than to any mild to modest positive pressure effect.3 Though there is limited data from trials in adults or pediatric patients, there are now three completed RCT trials comparing HHHFNC to CPAP in NICU patients (B. Manley's trial results only available as presented at Hot Topics, December 2012).4,5 These trials included 867 infants from 24-40 weeks gestation and focused much attention on adverse event rates. Independently and collectively these studies reported no differences in efficacy or in adverse event rates. Specifically, air leak events were extremely uncommon in both groups of infants with a slightly higher, but insignificant, rate occurring among CPAP infants. Many questions remain regarding HHHFNC use in children and continued investigations are in order. Incorrect application of any therapy may be dangerous. Available data support the safe and effective use of HHHFNC in the NICU. Providers using HHHFNC in pediatric and adult populations should undertake similar RCT's.
1. Sivieri EM, Gerdes JS, Abbasi S. Effect of HFNC flow rate, cannula size, and nares diameter on generated airway pressures: An in vitro study. Pediatr Pulmonol; 2012 Jul 23, ePub. 2. Chang GY, Cox CA, Shaffer TH. Nasal cannula, CPAP, and high-flow nasal cannula: Effect of flow on temperature, humidity, pressure, and resistance. Biomed Instrum Techn 2011; 45:69-74. 3. Dysart K, Miller TL, Wolfson MR, Shaffer TH. Research in high flow therapy: Mechanisms of action. Respir Med 2009; 103:1400-1405. 4. Collins CL, Holberton JR, Barfield C, Davis PG. A randomized controlled trial to compare heated humidified high-flow nasal cannulae with nasal continuous positive airway pressure post-extubation in premature infants. J Pediatr; 2012 Dec 19, ePub. 5. Yoder BA, Stoddard RA, Li M, King J, Dirnberger DR, Abbasi S. Heated humidified high flow nasal cannula versus nasal CPAP for respiratory support in neonates. Pediatrics, in press, 2013.
Conflict of Interest:
None declared