Electrical activity of the diaphragm during nCPAP and high flow nasal cannula

Objective To investigate the relationship between applied flows of nasal high flow (NHF) and physiological outcomes and work of breathing (WOB), to identify an optimal delivery flow which results in reduced WOB in preterm infants. Design A prospective observational clinical study with randomly applied NHF rates. Patients and Setting Preterm infants within 72 hours of commencement of NHF respiratory support. Interventions Infants were initially placed on 8 L/min of NHF and flows of 2, 4, and 6 L/min were then applied in random order. Measurements and Results WOB was measured using transcutaneous electromyography and respiratory inductance plethysmography. Physiological variables were also recorded. Measurements taken 10 minutes after each flow change were compared with 8 L/min. Sixteen infants with a median gestational age of 28 (range 24‐31) weeks and postnatal age of 14 (2‐55) days were included in the study. The median flow rate before the study was 6 (4‐8) L/min and a fraction of inspired oxygen (FiO2) was 0.21 (0.21‐0.26). Changes in flow resulted in changes in activity in the front diaphragm (P = .027) and intercostals (P = .034). The electrical activity of the front diaphragm at 8 L/min was significantly lower than that at 2 L/min (P = .016). Respiratory rate was lowest at 6 L/min (P = .002) and SpO2/FiO2 was highest at 8 L/min (P < .04). Conclusion In preterm infants, changes in WOB resulting from randomly applied levels of NHF can be demonstrated by measuring the electrical activity of the diaphragm and intercostal muscles with transcutaneous electromyography. In combination with physiological measurements, the similarities in electrical activity between 4, 6, and 8 L/min suggest that these three flows may be equally as effective.

Section: Discussionmentioning

confidence: 90%

Section: Discussionmentioning

confidence: 99%

Nasal high flow in preterm infants: A dose‐finding study

Hough

Shearman

Jardine

et al. 2019

“…Several randomized crossover studies have attempted to investigate the effects of NCPAP and HFNC on physiological parameters. These studies revealed no differences in heart and respiratory rate, FiO 2 levels, oxygen saturation, work of breathing, thoraco‐abdominal asynchrony, or electrical activity of the diaphragm . However, the studies included more mature infants clinically stable on NCPAP for several days at the time of the measurements.…”

Section: Discussionmentioning

confidence: 99%

The effects of nasal continuous positive airway pressure and high flow nasal cannula on heart rate variability in extremely preterm infants after extubation: A randomized crossover trial

Latremouille

Shalish

Kanbar³

et al. 2019

Background NCPAP and High flow nasal cannula (HFNC) are common modes of non‐invasive respiratory support used after extubation. Heart rate variability (HRV) has been demonstrated as a marker of well‐being in neonates and differences in HRV were described in preterm infants receiving respiratory care. The objective was to investigate the effects of NCPAP and HFNC on HRV after extubation. Methods Randomized crossover trial in infants with birth weight (BW) ≤1250 g after undergoing their first elective extubation. ECG recordings were performed during 45 min while on HFNC and nasal continuous positive airway pressure (NCPAP). Time domain, non‐linear, and frequency domain parameters were calculated and compared during HFNC and NCPAP using paired nonparametric tests. A secondary analysis was performed in the subgroup of infants that were successfully extubated. Results Thirty infants with median [range] gestational age of 27 weeks [24.1‐29.3] and BW of 930 g [610‐1220] were studied at 5 days [1‐39] of age. No differences in HRV parameters were observed between HFNC and NCPAP. In the secondary analysis, infants successfully extubated (n = 27) had a significantly higher HRV during HFNC for some time domain parameters. For instance, the standard deviation of the RR intervals (SDRR) was more likely to be higher during HFNC compared to NCPAP (HFNC: 18/27 vs NCPAP: 9/27, P = 0.017) . Conclusion During the first hours after extubation, no differences in HRV were detected between HFNC and NCPAP in the overall cohort. However, a significantly higher HRV was noted during HFNC in the subgroup of infants successfully extubated.

“…dEMG measures the electrical activity of the frontal diaphragm with three surface electrodes. Previous research has shown that dEMG accurately measures HR and RR, compared with CI, and does provide information on respiratory effort in preterm infants …”

Section: Introductionmentioning

confidence: 99%

“…This information is essential before this technique can be implemented as a reliable cardiorespiratory monitor in preterm infants in the neonatal intensive care unit (NICU). If alternative electrode positions to measure dEMG would show similar reliability in vital signs, this could introduce numerous clinical applications, including apnea detection and classification, and more objective weaning of respiratory support based on electrical activity of respiratory muscles . The aim of this observational study was to describe the effect of changing the electrode positions on the registration of vital signs and respiratory effort parameters measured by dEMG in preterm infants.…”

Section: Introductionmentioning

confidence: 99%

Diaphragmatic electromyography in preterm infants: The influence of electrode positioning

Leuteren

Bekhuis

Waal

et al. 2019

Objective To determine the effect of changing electrode positions on vital signs and respiratory effort parameters measured with transcutaneous electromyography of the diaphragm (dEMG) in preterm infants. Methods In this observational study, simultaneous dEMG measurements were performed at the standard position and at one alternative electrode position (randomly assigned to lateral, superior, medial, inferior to the standard placement, or dorsal). The activity of the diaphragm was measured for 1 hour at both positions. Main outcome measures were the agreement in heart rate (HR), respiratory rate (RR), and percentage difference in dEMG parameters of respiratory effort (peak and tonic activity, amplitude, area under the curve, and frequency content) between the standard and alternative electrode positions. Results Thirty clinically stable preterm infants (gestational age 30.1 ± 3.0 weeks) with either no or noninvasive respiratory support were included. Agreement in HR was excellent at all positions (ICC > 0.95) while RR agreement showed more diversity (ICC range 0.40‐0.86). Mixed modeling of dEMG parameters revealed that medial and inferior placement measured the weakest signals (median 75.5% and 64.5% lower dEMG amplitude). Lateral electrode placement showed the highest similarity to standard positioning (median 23.5% lower amplitude). Conclusion Measuring HR showed high similarity at all positions. However, registration of RR and respiratory effort is clearly influenced by the electrode position. Electrodes in the same transversal plane as the diaphragm, and at sufficient distance from each other, provide the best agreement with the standard positioning.