Nasopharyngeal oxygen therapy produces positive end-expiratory pressure ininfants

Citation
B. Frey et al., Nasopharyngeal oxygen therapy produces positive end-expiratory pressure ininfants, EUR J PED, 160(9), 2001, pp. 556-560
Citations number
18
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Pediatrics,"Medical Research General Topics
Journal title
EUROPEAN JOURNAL OF PEDIATRICS
ISSN journal
0340-6199 → ACNP
Volume
160
Issue
9
Year of publication
2001
Pages
556 - 560
Database
ISI
SICI code
0340-6199(200109)160:9<556:NOTPPE>2.0.ZU;2-4
Abstract
The World Health Organisation recommends nasopharyngeal catheters as a safe and efficient method of oxygen administration in infants. However, little is known about the mechanisms of the improvement in oxygenation. The aim of the present study was to determine whether nasopharyngeal oxygen therapy p roduces positive end-expiratory pressure (PEEP). Nine spontaneously breathi ng infants (median age 13 months, range 10 days to 20 months) after heart s urgery were investigated. All patients had normal pulmonary blood flow at t he time of the study (Qp:Qs = 1:1). Oxygen (oxygen fraction 1.0) was delive red by an 8 F catheter inserted into the nasopharynx (tip just visible belo w the soft palate). The pulmonary mechanics were analysed using a single co mpartment model of the respiratory system. Oesophageal. pressure (Pes) at e nd-expiration, dynamic lung compliance (C-L.) and resistance (R-L), minute ventilation, PaCO2 and PaO2 Were measured at baseline without a nasopharyng eal catheter or oxygen, and at oxygen flows of 0.5 l/min, 1.0 l/min and 2.0 l/min. All the flows generated significant increases in PEEP. Mean differe nce in PEEP (SD, paired t-test versus baseline): 1.6 cm, H2O (1.4, P=0.008) with 0.5 l/min of oxygen; 2.8 cm. H2O (2.7, P=0.014) with 1.0 l/min of oxy gen; and 4.0 cm H2O (2.9, P=0.004) with 2.0 l/min of oxygen. There was a si gnificant correlation between all the nasopharyngeal flows (in ml/kg per mi n) and the generated PEEP (P <0.001) and between the C-L values and the gen erated PEEP (P <0.05). There was no significant difference in PaCO2 and R-L . Minute ventilation was significantly less with nasopharyngeal oxygen than at baseline. As expected, PaO2 increased significantly with increasing oxy gen flows. Conclusion: Administration of oxygen through an 8 F nasopharynge al catheter at flow rates recommended by the World Health Organisation (0.5 l/min in newborns, 1.0 l/min in infants) produces moderate amounts of posi tive end-expiratory pressure. The levels achieved may contribute to:an impr ovement in oxygenation by altering the visco-elastic properties of the lung .