Work of breathing indices in infants with respiratory insufficiency receiving high-flow nasal cannula and nasal continuous positive airway pressure.
OBJECTIVE
To compare work of breathing (WOB) indices between two nCPAP settings and two levels of HFNC in a crossover study.


METHODS
Infants with a CGA 28-40 weeks, baseline of HFNC 3-5 lpm or nCPAP 5-6 cmH2O and fraction of inspired oxygen ≤40% were eligible. WOB was analyzed using respiratory inductive plethysmography (RIP) for each of the four modalities: HFNC 3 and 5 lpm, nCPAP 5 and 6 cmH2O. N=20; Study weight 1516 g (±40 g).


RESULTS
Approximately 12,000 breaths were analyzed indicating a high degree of asynchronous breathing and elevated WOB indices at all four levels of support. Phase angle values (means) (P<0.01): HFNC 3 lpm (114.7°), HFNC 5 lpm (96.7°), nCPAP 5 cmH2O (87.2°), nCPAP 6 cmH2O (80.5°). The mean phase relation of total breath (PhRTB) (means) (P<0.01): HFNC 3 lpm (63.2%), HFNC 5 lpm (55.3%), nCPAP 5 cmH2O (49.3%), nCPAP 6 cmH2O (48.0%). The relative labored breathing index (LBI) (means) (P≤0.001): HFNC 3 lpm (1.39), HFNC 5 lpm (1.31), nCPAP 5 cmH2O (1.29), nCPAP 6 cmH2O (1.26). Eighty-two percent of the study subjects-respiratory mode combinations displayed clustering, in which a proportion of breaths either occurred predominantly out-of-phase (relative asynchrony) or in-phase (relative synchrony).


CONCLUSIONS
In this study, WOB indices were statistically different, yet clinically similar in that they were elevated with respect to normal values. These infants with mild-to-moderate respiratory insufficiency demonstrate a meaningful elevation in WOB indices and continue to require non-invasive respiratory support. Patient variability exists with regard to biphasic clustered breathing patterns and the level of supplemental fraction of inspired oxygen ≤40% alone does not provide guidance to the optimal matching of WOB indices and non-invasive respiratory support.
1] Department of Neonatology, St Christopher's Hospital for Children, Philadelphia, PA, USA [2] Department of Pediatrics, Drexel University College of Medicine, Philadelphia, PA, USA.
B E
BE
de Jongh
1] Department of Neonatology, Christiana Care Health System, Newark, DE, USA [2] Department of Pediatrics/Neonatology, Thomas Jefferson University, Philadelphia, PA, USA.
R
R
Locke
Department of Neonatology, Christiana Care Health System, Newark, DE, USA.
A
A
Mackley
Department of Neonatology, Christiana Care Health System, Newark, DE, USA.
J
J
Emberger
Department of Neonatology, Christiana Care Health System, Newark, DE, USA.
D
D
Bostick
1] Department of Neonatology, Christiana Care Health System, Newark, DE, USA [2] Department of Pediatrics/Neonatology, Thomas Jefferson University, Philadelphia, PA, USA.
J
J
Stefano
Nemours Research Lung Center, Alfred I duPont Children's Hospital, Wilmington, DE, USA.
E
E
Rodriguez
1] Department of Pediatrics/Neonatology, Thomas Jefferson University, Philadelphia, PA, USA [2] Nemours Research Lung Center, Alfred I duPont Children's Hospital, Wilmington, DE, USA.
T H
TH
Shaffer
D045422:Continuous Positive Airway Pressure; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D008297:Male; D010102:Oxygen Inhalation Therapy / Q000295:instrumentation / Q000379:methods*; D010991:Plethysmography; D012131:Respiratory Insufficiency / Q000503:physiopathology* / Q000628:therapy; D014939:Work of Breathing