Continuous positive airway pressure titration in infants with severe upper airway obstruction or bronchopulmonary dysplasia

Khirani et al. Critical Care 2013, 17:R167 http://ccforum.com/content/17/4/R167 RESEARCH Open Access Continuous positive airway pressure titration in infants with severe upper airway obstruction or bronchopulmonary dysplasia Sonia Khirani1,2, Adriana Ramirez2,3, Sabrina Aloui2, Nicolas Leboulanger4,5,6, Arnaud Picard5,7 and Brigitte Fauroux2,5,6* Abstracta Introduction: Noninvasive continuous positive airway pressure (CPAP) is recognized as an effective treatment for severe airway obstruction in young children. The aim of the present study was to compare a clinical setting with a physiological setting of noninvasive CPAP in infants with nocturnal alveolar hypoventilation due to severe upper airway obstruction (UAO) or bronchopulmonary dysplasia (BPD). Methods: The breathing pattern and respiratory muscle output of all consecutive infants due to start CPAP in our noninvasive ventilation unit were retrospectively analysed. CPAP set on clinical noninvasive parameters (clinical CPAP) was compared to CPAP set on the normalization or the maximal reduction of the oesophageal pressure (Poes) and transdiaphragmatic pressure (Pdi) swings (physiological CPAP). Expiratory gastric pressure (Pgas) swing was measured. Results: The data of 12 infants (mean age 10 ± 8 mo) with UAO (n = 7) or BPD (n = 5) were gathered. The mean clinical CPAP (8 ± 2 cmH2O) was associated with a significant decrease in Poes and Pdi swings. Indeed, Poes swing decreased from 31 ± 15 cmH2O during spontaneous breathing to 21 ± 10 cmH2O during CPAP (P < 0.05). The mean physiological CPAP level was 2 ± 2 cmH2O higher than the mean clinical CPAP level and was associated with a significantly greater improvement in all indices of respiratory effort (Poes swing 11 ± 5 cm H2O; P < 0.05 compared to clinical CPAP). Expiratory abdominal activity was present during the clinical CPAP and decreased during physiological CPAP. Conclusions: A physiological setting of noninvasive CPAP, based on the recording of Poes and Pgas, is superior to a clinical setting, based on clinical noninvasive parameters. Expiratory abdominal activity was present during spontaneous breathing and decreased in the physiological CPAP setting. Keywords: Airway obstruction, Continuous positive airway pressure, Oesophageal pressure, Expiratory abdominal activity, Infant Introduction Noninvasive continuous positive airway pressure (CPAP) is recognized as an effective treatment for severe upper airway obstruction (UAO) in young children. Indeed, the maintenance of airway patency throughout the entire breathing cycle by means of CPAP has been shown to be * Correspondence: 2 AP-HP, Hôpital Armand Trousseau, Pediatric Pulmonary Department, Paris, France Full list of author information is available at the end of the article associated with an unloading of the respiratory muscles, an improvement of breathing pattern and gas exchange [1-6]. In adults and adolescents with obstructive sleep apnoea (OSA), the titration of CPAP is based on the polysomnographic disappearance of apnoea, hypopnoea, respiratory effort-related arousal and snoring, as recommended by the American Academy of Sleep Medicine (AASM) [7,8]. The diseases responsible for airway obstruction in infants differ from those of older children and adults with the predominance of anatomical abnormalities of the upper airways such as laryngomalacia or tracheomalacia, © 2013 Fauroux et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Khirani et al. Critical Care 2013, 17:R167 http://ccforum.com/content/17/4/R167 Pierre Robin syndrome or other maxillofacial malformations [3,6]. Some other diseases involving the lower respiratory tract, such as chronic lung diseases of prematurity, also called bronchopulmonary dysplasia (BPD), are associated with lung diseases and predominantly peripheral airway obstruction, which may be severe and cause intrinsic positive end-expiratory pressure (PEEPi). Because of these differences in pathophysiology and the lack of guidelines for this age group, the titration of CPAP in infants is generally based on clinical parameters such as the disappearance of the stridor and retractions, the decrease in respiratory and heart rates and the normalization of gas exchange [2,3]. To facilitate the acclimatization of the infant with CPAP, the initial level is usually set at 4 cmH2O, followed by a gradual increase of the CPAP level until the best clinical efficacy and comfort are obtained. Importantly, small changes in the CPAP level may have significant clinical consequences. Indeed, the minimal airway diameter is the most critical because, according to Poiseuille’s law, the resistance increases with an exponent 4 of the radius. This has been observed in infants with acute viral bronchiolitis, in whom a 2 cmH2O change of CPAP level was associated with a significant change in the work of breathing and breathing pattern [9]. In such a homogeneous group of infants, the optimal CPAP level, determined by monitoring the oesophageal (Poes) and gastric pressure (Pgas), was 7 cmH2O for all the patients; however, it is not known if this level is also appropriate for infants with UAO and BPD, in whom CPAP could counteract the PEEPi. The aim of the present study was to compare two settings of CPAP: a first setting based on noninvasive clinical parameters and a second setting based on the invasive recording of Poes and Pgas in a group of infants with severe UAO or BPD. Materials and methods Patients All the data of consecutive infants less than 24 months old with severe UAO or BPD evaluated for noninvasive CPAP in a noninvasive ventilation unit of a paediatric university hospital were retrospectively analysed. All the patients with UAO had a laryngotracheal endoscopy under general anaesthesia. The UAO persisted in all the UAO patients despite endoscopic resection of the aryepiglottic folds and antireflux treatment using proton pump inhibitors. All the UAO and BPD patients were hypoxaemic (pulse oximetry (SpO 2) less than 90% for more than 10 consecutive min and/or more than 10% of sleep time) and hypercapnic (transcutaneous carbon dioxide pressure (PtcCO2) above 50 mmHg for more than 10 consecutive min and/or more than 10% of sleep time) Page 2 of 9 during an overnight sleep study [6]. Exclusion criteria were severe mental retardation and important midfacial deformity precluding the tolerance of a nasal mask. The study was approved by the Institutional Review Board of the French learned society for respiratory medicine, Société de Pneumologie de Langue Française (CEPRO 2012-031), and all the parents gave informed consent for the CPAP evaluation of their children. CPAP equipment Because of the lack of adequate nasal interfaces for (...truncated)