Current criteria for surfactant administration assume that hypoxia is a direct marker of lung-volume de-recruitment. We first introduced an early, non-invasive assessment of lung mechanics by the ...Forced Oscillation Technique (FOT) and evaluated its role in predicting the need for surfactant therapy.
To evaluate whether lung reactance (Xrs) assessment by FOT within 2 h of birth identifies infants who would need surfactant within 24 h; to eventually determine Xrs performance and a cut-off value for early detection of infants requiring surfactant.
We conducted a prospective, observational, non-randomized study in our tertiary NICU in Milan. Eligible infants were born between 27
and 34
weeks' gestation, presenting respiratory distress after birth.
endotracheal intubation at birth, major malformations participation in other interventional trials, parental consent denied. We assessed Xrs during nasal CPAP at 5 cmH
O at 10 Hz within 2 h of life, recording flow and pressure tracing through a Fabian Ventilator for off-line analysis. Clinicians were blinded to FOT results.
We enrolled 61 infants, with a median IQR gestational age of 31.9 30.3; 32.9 weeks and birth weight 1490 1230; 1816 g; 2 infants were excluded from the analysis for set-up malfunctioning. 14/59 infants received surfactant within 24 h. Xrs predicted surfactant need with a cut-off - 33.4 cmH
O*s/L and AUC-ROC = 0.86 (0.76-0.96), with sensitivity 0.85 and specificity 0.83. An Xrs cut-off value of - 23.3 cmH
O*s/L identified infants needing surfactant or respiratory support > 28 days with AUC-ROC = 0.89 (0.81-0.97), sensitivity 0.86 and specificity 0.77. Interestingly, 12 infants with Xrs < - 23.3 cmH
O*s/L (i.e. de-recruited lungs) did not receive surfactant and subsequently required prolonged respiratory support.
Xrs assessed within 2 h of life predicts surfactant need and respiratory support duration in preterm infants. The possible role of Xrs in improving the individualization of respiratory management in preterm infants deserves further investigation.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Background
Oscillatory pressure (ΔP) measurement during high frequency oscillatory ventilation (HFOV) is technically challenging and influenced by all the components of the measurement system.
...Objectives
To evaluate the differences between the ΔP delivered at the inlet of the endotracheal tube and those displayed by commercial neonatal mechanical ventilators and monitoring devices and to characterize how the ventilator circuit and the flowmeter proximal to the patient affect these differences.
Methods
Six devices were evaluated while ventilating three mechanical analogues representing the newborn respiratory system in different disease states. ΔP measured at different points of the ventilator circuit were compared.
Results
ΔP accuracy is highly variable and decreases with increasing oscillation frequency and amplitude, independently of the mean airway pressure. At 15 Hz, a ΔP displayed by ventilators of 40 cmH2O resulted in a ΔP effectively delivered at the tracheal tube ranging from 22 to 49 cmH2O, depending on the ventilator model, the ventilator circuit, and the patient condition. At these settings, the errors exclusively due to the ventilator circuit and the presence of the flowmeter ranged from 6 to 9 cmH2O and from 1 to 6 cmH2O, respectively.
Conclusions
The ventilator model, the breathing circuit, the flowmeter, and the patient condition severely impacts ΔP measurement accuracy during HFOV, leading to highly variable performances. This prevents the possibility of using the ΔP required to normalize gas exchange as an indicator of patients’ condition, complicates comparison of ventilators performances, and adds a significant element of complexity in clinical management of HFOV.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Objective
Despite technical specifications of neonatal mechanical ventilators (MVs) guarantee clinically irrelevant discrepancies between the set and the delivered values of ventilation parameters, ...previous studies reported large deviations. Most studies characterized performances of a given model/brand by studying a single device, disregarding possible intramodel differences, and leaving the accuracy of the ventilation parameters effectively delivered in clinical settings unknown. The aim of this study was to evaluate the real‐life accuracy of pressure and volume parameters delivered by neonatal ventilators ready to be used on patients in neonatal intensive care units (NICUs).
Study Design
In vitro study.
Subjects Selection
Neonatal ventilators (n = 33 of 8 different models) available in four European NICUs.
Methodology
The MVs were connected to a test lung (resistance = 50 cmH2O*s/L, compliance = 0.35 mL/cmH2O) provided with pressure and flow sensors. MVs were tested over two different ventilation modes randomly: (a) pressure controlled (PC) with a peak inspiratory pressure (PIP) of 22 cmH2O, and (b) PC with volume targeted ventilation (VTV) with a tidal volume (VT) of 6 mL. In all tests, positive end‐expiratory pressure (PEEP) was set to 6 cmH2O, respiratory rate to 45 breaths/min, inspiratory time to 0.33 seconds, and oxygen fraction to 0.3.
Results
During PC the median (min‐max) values delivered were: PEEP = 5.84(4.95‐6.48) cmH2O, PIP = 21.63(20.04‐22.62) cmH2O. During VTV, VT was 5.94(4.63‐8.01) mL. VT was considerably variable, ranging from −22% to +33% of the set and displayed values. Differences in accuracy among devices of the same model were comparable to those found among different models.
Conclusions
Our findings suggest that loss of accuracy in ventilation variables is likely related to daily use of the devices rather than weakness in the design or manufacturing process, urging the improvement of maintenance and quality control procedures to preserve the performances of neonatal MVs during their entire lifespan.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
The evolution of the solid electrolyte interface (SEI) in carbon‐coated ZnFe2O4 (ZFO‐C) anodes is studied by soft X‐ray absorption spectroscopy (XAS). Experiments probe locally the SEI growth in the ...2–100 nm range, using both total electron (TEY) and total fluorescence (TFY) yield techniques. XAS analysis shows that the SEI grows preferentially around the ZFO‐C nanoparticles.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
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