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To determine if the use of closed-loop automated oxygen control (CLAC) reduced the incidence and duration of hypoxemic episodes (SpOInfants were studied on two consecutive days for 6 h each day. They were randomised to receive standard care (manual oxygen control) or standard care with a CLAC system (automated oxygen control) first.Sixteen infants with a median (IQR) gestational age of 37.4 (36.6-38.8) weeks were studied at a median (IQR) postmenstrual age of 38.8 (37.4-39.8) weeks. During the automated oxygen control period, infants spent less time in hypoxemia (SpOClosed-loop automated oxygen control in ventilated infants born at or near term was associated with a reduction in the incidence and duration of hypoxemic episodes with more time spent in the target oxygen range.

We hypothesised that extremely premature infants would have decreased muscle mass at term-corrected age compared to term-born infants and that the degree of reduced muscle mass acquisition would correlate with the duration of invasive mechanical ventilation. The MRI brain scans of infants admitted in the neonatal unit at King's College Hospital between 1 January 2010 and 1 June 2016 were retrospectively reviewed. The coronal cross-sectional area of the left deltoid muscle (DCSA) was measured in 17 infants born 28 weeks of gestation and in 20 infants born at term. The prematurely born infants had a median (IQR) gestation age of 25 weeks (24-27) and the term infants 40 weeks (38-41). The duration of invasive mechanical ventilation for the prematurely born infants was 39 days (14-62) and that for the term infants 4 days (2-5), p 0.001. DCSA was smaller in prematurely born infants (median 189, IQR 176-223 mmOur results suggest that prolonged mechanical ventilation in infants admitted in neonatal intensive care is associated with reduced skeletal muscle mass acquisition. What is Known: • Prolonged mechanical ventilation in adult intensive care patients has been associated with skeletal muscle dysfunction and atrophy. • The cross-sectional area of the deltoid muscle has been used to evaluate muscle atrophy in infants with a previous branchial plexus birth injury. What is New: • Premature infants studied at term exhibit lower cross-sectional area of the deltoid muscle than their term counterparts. • Prolonged mechanical ventilation could be associated with skeletal muscle impairment.

Background Pulmonary dead space (VD) is an index of ventilation inhomogeneity and one of the determinants of the magnitude of tidal volume to maintain optimal blood gases. Aims To identify the determinants of VD in ventilated newborns and to investigate differences in VD between prematurely born and term infants and those prematurely born infants who did or did not develop bronchopulmonary dysplasia (BPD). Methods Sixty-one mechanically ventilated infants (15 term, 46 preterm) were studied at a median age of 8 (IQR 2–31) days; 32 of the preterm infants developed BPD. VD was determined from the difference between arterial and end tidal carbon dioxide (CO2) using a low dead space CO2 detector using the Bohr/Enghoff equation and was related to body weight (VD/kg) at the time of study. The time to peak tidal expiratory flow/expiratory time (TPTEF/TE) was measured during spontaneous breathing using a fixed orifice pneumotachograph. Results VD/kg was related to gestational age (r = − 0.285, p = 0.001), birth weight (r = − 0.356, p < 0.001), weight (r = − 0.316, p < 0.001) and postmenstrual age (r = − 0.205, p = 0.020) at measurement, days of ventilation (r = 0.322, p < 0.001) and TPTEF/TE (r = − 0.397, p = 0.003). The median VD/kg was higher in prematurely born infants [2.3 (IQR: 1.7–3.0) ml/kg] compared to term infants [1.5 (1.3–2.1) ml/kg, (p = 0.003)] and in premature infants that developed BPD [2.6 (IQR 1.8–3.4) ml/kg] compared to those who did not [1.7 (IQR 1.1–1.9) ml/kg], (p < 0.001). Conclusions Numerous factors influence pulmonary dead space and thus an optimum tidal volume will differ according to the underlying demographics and respiratory status.

Background: Accurate prediction of extubation outcome could result in a significant reduction of respiratory morbidity in premature neonates. Objectives: To assess whether the respiratory muscle time constant of relaxation (τ) predicted extubation outcome in mechanically ventilated, premature infants. Methods: Forty-six mechanically ventilated infants with a median gestational age of 26 (interquartile range [IQR] 25-29) weeks were prospectively studied. τ was calculated from the reciprocal of the slope of the decline in airway pressure as a function of time. Measurements of τ were done during 5-10 min of a spontaneous breathing test (SBT) prior to extubation. During the first and last minute of the SBT, τ1 and τ2, respectively, were assessed, and the difference between them was calculated (Δτ). Results: The median τ2 was significantly higher in infants whose extubation failed (20.7 [IQR 12.9-34.7] s/cm H2O) than in infants whose extubation succeeded (8.2 [IQR 6.2-17.8] s/cm H2O, p = 0.002). The median Δτ was significantly higher in infants whose extubation failed (10.3 [IQR 4.4-23.9] s/cm H2O) than in infants whose extubation succeeded (-1.63 [IQR -5.7 to 0.3] s/cm H2O, p = 0.001). Extubation failure was associated with τ2 (p = 0.011) and Δτ (p = 0.010) after correcting for postmenstrual age, patent ductus arteriosus, and intraventricular haemorrhage. Receiver operator characteristic curve analysis demonstrated that Δτ predicted extubation failure with an area under the curve of 0.937. A Δτ of +1.02 s/cm H2O predicted extubation failure with 94% sensitivity and 83% specificity. Conclusions: The respiratory muscle time constant of relaxation during an SBT was significantly greater in infants whose extubation failed and could be used to predict extubation outcome in prematurely born infants.

AIM To assess the respiratory muscle time constant of relaxation (τ), an index of respiratory muscle function in ventilated newborns. METHODS Sixty-two infants (42 born prematurely) with a median gestational age of 29 [interquartile range (IQR) 26-37] weeks were prospectively studied. Measurement of τ was taken during spontaneous breathing on endotracheal continuous positive airway pressure prior to extubation, and τ was calculated from the reciprocal of the slope of the airway pressure decline versus time. Infants were classified as having had systemic or respiratory infection (positive microbiology) if they had any positive bacterial blood or respiratory culture prior to measurement. RESULTS Measurement of τ was taken at a median post-natal age of 6 (IQR 3-29) days. The median τ was higher in premature infants [17.4 (IQR 7.7-28.3) sec/cmH2 O] compared to term infants [6.8 (IQR 4.4-8.7) sec/cmH2 O, p