Adjustment of high flow nasal cannula rates using real-time work of breathing indices in premature infants with respiratory insufficiency

Work of Breathing: Physiology, Measurement, and Diagnostic Value in Childhood Pneumonia

In clinical practice, increased "work of breathing" (WOB) is used to rapidly identify the acutely ill child in need of immediate clinical care, and is commonly used to support a clinical diagnosis of pneumonia. However, this key clinical sign is poorly understood and inconsistently defined. This review discusses the physiology, measurement, and clinical assessment of WOB, highlighting its utility in the recognition of pneumonia in under-resourced settings, where access to diagnostic imaging may be limited.

The effects of flow settings during high-flow nasal cannula oxygen therapy for neonates and young children

BACKGROUND

During neonatal and paediatric high-flow nasal cannula therapy, optimising the flow setting is crucial for favourable physiological and clinical outcomes. However, considerable variability exists in clinical practice regarding initial flows and subsequent adjustments for these patients. Our review aimed to summarise the impact of various flows during high-flow nasal cannula treatment in neonates and children.

METHODS

Two investigators independently searched PubMed, Embase, Web of Science, Scopus and Cochrane for in vitro and in vivo studies published in English before 30 April 2023. Studies enrolling adults (≥18 years) or those using a single flow setting were excluded. Data extraction and risk of bias assessments were performed independently by two investigators. The study protocol was prospectively registered with PROSPERO (CRD42022345419).

RESULTS

38 406 studies were identified, with 44 included. In vitro studies explored flow settings' effects on airway pressures, humidity and carbon dioxide clearance; all were flow-dependent. Observational clinical studies consistently reported that higher flows led to increased pharyngeal pressure and potentially increased intrathoracic airway pressure (especially among neonates), improved oxygenation, and reduced respiratory rate and work of breathing up to a certain threshold. Three randomised controlled trials found no significant differences in treatment failure among different flow settings. Flow impacts exhibited significant heterogeneity among different patients.

CONCLUSION

Individualising flow settings in neonates and young children requires consideration of the patient's peak inspiratory flow, respiratory rate, heart rate, tolerance, work of breathing and lung aeration for optimal care.

Oxygen saturation and work of breathing indices in preterm infants with bronchopulmonary dysplasia compared to healthy preterm infants at discharge

BACKGROUND

Thoracoabdominal asynchrony (TAA) is commonly seen in preterm infants. Respiratory inductive plethysmography (RIP) is a noninvasive way to objectively assess work of breathing (WOB) indices. The impact of bronchopulmonary dysplasia (BPD) on TAA at discharge has not been established. The aim of this study is to compare WOB indices in premature infants with a diagnosis of BPD to premature infants without a diagnosis of BPD at discharge.

METHODS

A prospective, observational study of premature infants (<32 weeks gestation) at discharge during quiet breathing in the supine position. RIP noninvasively measured WOB indices. A high-resolution pulse oximeter collected oxygen saturation and heart rate data.

RESULTS

This study included thirty-one infants with BPD and thirty-four infants without BPD. Infants diagnosed with BPD had increased phase angle [BPD Φ = 73 . 90 (8.2) vs NoBPD Φ = 52.6 (8.2), p = 0.039]. Infants diagnosed with BPD had decreased saturations [BPD SpO2 = 96% (0.4) vs NoBPD Sp02 98% (0.3), p=<0.001], increased time with saturations less than 85% [BPD % =2.74 (0.7) vs NoBPD % =0.91 (0.4), p = .018], and increased time with saturations less than 80% [BPD % =1.57 (0.5) vs NoBPD % =0.52 (0.3), p = 0.045]. There was no difference in heart rate or breaths per minute for infants with BPD versus controls.

CONCLUSION

Premature infants with BPD demonstrated increased TAA and had lower saturations compared to infants without BPD at discharge despite being chronologically older and being discharged at an older corrected gestational age. The impact of BPD on breathing patterns persists at discharge and suggests these patients may have residual lung and/or respiratory muscle dysfunction.

The impact of kangaroo mother care on work of breathing and oxygen saturation in very low birth weight infants with respiratory insufficiency

BACKGROUND: Kangaroo mother care (KMC) is defined as prolonged skin to skin care between a mother and infant with the infant lying in prone position on mom’s chest. KMC decreases morbidity and mortality and promotes physiologic stability. The aim of this study is to measure work of breathing (WOB) during KMC in very low birth weight (VLBW) infants on non-invasive respiratory support. METHODS: A prospective observational pilot study was conducted comparing WOB indices during standard care (SC) and KMC. Respiratory inductive plethysmography (RIP) measured WOB indices non-invasively: phase angle and labored breathing index. VLBW infants who were stable on non-invasive respiratory support were randomized to receive RIP measurements during KMC or during SC first. Summary statistics and mixed linear models were used to compare WOB and vital signs. RESULTS: A total of 32 infants were consented for the study, data collection and analysis was completed on 28 infants. There were no significant differences in mean phase angle during KMC or SC (73.5±4.6 SE deg vs 66.8±3.9 SE deg, p = 0.25). No differences in WOB and vital signs were detected. Controlling for respiratory support or randomization/first location did not change the results. CONCLUSION: In this pilot cohort, infants demonstrated no differences in work of breathing indices or oxygen saturation during KMC or SC while receiving non-invasive respiratory support. KMC appears to be safe and well tolerated with no worsened WOB. Larger studies should be performed to confirm our findings.

Utilising pneuRIP device in determining the adequacy of respiratory support when weaning high-flow nasal cannula in paediatric patients with acute respiratory distress: A pilot study

AIM

Recognition of paediatric respiratory distress and timely intervention is critical, especially during the weaning phase of support in paediatric acute respiratory failure, as weaning too aggressively can lead to further setbacks in a patient's recovery. We aimed to determine if pulmonary function measurements obtained with the pneuRIP device, a noninvasive pulmonary function testing device that provides measurements of labored breathing index (LBI), phase angle and %rib cage (%RC) contribution to breathing, will provide predictive values to assess the adequacy of respiratory support while weaning from HFNC.

METHODS

We reviewed patients ages 0-18 years admitted to the PICU for respiratory distress due to respiratory infections receiving HFNC. Patients with history of chronic lung disease and chronic neuromuscular disease with baseline habnormal breathing patterns were excluded. Phase angle, LBI and %RC were obtained every hour and with every wean of HFNC. Nine patients were enroled.

RESULTS

Mean LBI range remained 1.27-1.68 when LBI was plotted as a function of the HFNC flow rate. Mean values of %RC contribution to breathing ranged 43.65-57.12 as a function of the HFNC flow rate. No significant deviations existed in either %RC (P = 0.16) or LBI (P = 0.16) during the weaning of HFNC. Mean phase angle for all subjects was 41.48°-74.12° for the duration of wean and showed significant deviation from baseline during the weaning process (p = 0.001).

CONCLUSIONS

Measurements of LBI and %RC on the pneuRIP device effectively demonstrated tolerance of weaning HFNC during the recovery phase of acute respiratory failure from a respiratory infection.