Background Multisite Near-infrared spectroscopy (NIRS) monitoring may help to detect circulatory failure in preterm infants. The aim of this study was to assess the correlation between multisite NIRS-measurements and routine haemodynamic measurements in preterm infants with clinical sepsis.

Methods Prospective exploratory cohort study in which preterm infants (GA²Leiden University Medical Centre, Leiden University, Leiden, Netherlands.

Background Heating and humidification of inspired gas is routine during neonatal non-invasive respiratory support, but little is known about the effects of different techniques on temperature and humidity in the upper airway.

Method Eight non-invasive respiratory support modes were applied to a neonatal manikin, in an incubator set to 34^oC with relative humidity (RH) 60% (approximate normal upper airway conditions). Continuous positive airway pressure (CPAP), high-flow nasal cannulae (HFNC), and low-flow nasal cannulae (LFNC) devices were tested. Except for unhumidified LFNC, set humidifier temperature was 37^oC. Typically used pressures and gas flows were assessed. Temperature and RH in the manikin’s oropharynx were measured every 5 min for 30 min, using a thermohygrometer. Each variation was repeated 3 times.

Results Steady state was reached by 10 min. Median values from 10–30 min are shown below.

Conclusions Achieved oropharyngeal temperature and RH varied between devices. RH of 0.8% occurred during LFNC using unconditioned ‘dry’ gas. Most devices achieved temperatures >34^oC and >80% RH. Bubble CPAP delivered by Hudson prongs resulted in an oropharyngeal temperature above body temperature, which could result in water condensation as gas cools in the airway.