Univariable, multilevel linear regression analyses of scaling exponent alpha and sample entropy of body temperature.

<p>Univariable, multilevel linear regression analyses of scaling exponent alpha and sample entropy of body temperature.</p

Scaling exponent alpha (T_alpha) over postnatal age.

<p>T_alpha decreased from a mean (SD) of 1.67 (0.18) on day one of life to 1.46 (0.22) on day five of life (p<0.001).</p

Sensitivity analysis related to amount and fragmentation of data.

<p>Sensitivity analysis related to amount and fragmentation of data.</p

Flow of patients and measurements through the phases of the study.

<p>Flow of patients and measurements through the phases of the study.</p

Scaling exponent alpha (T_alpha) over respiratory support.

<p>T_alpha grouped by the level of respiratory support present during a temperature measurement. Multilevel linear regression analysis demonstrated a significant positive association between T_alpha and stepwise increase of respiratory support from none to continuous positive airway pressure (CPAP), and from CPAP to endotracheal ventilation (p < 0.001, R² = 0.29).</p

Anthropometric data of the study infants.

<p>Data is given as mean+/−SD (range).</p>1<p>Body mass index, calculated as weight divided by length.</p>2<p>Data on maternal smoking during pregnancy was available only in 399 out of the 424 infants.</p

Receiver-operator characteristic (ROC) curves comparing <i>t</i>_PTEF/<i>t</i>_E (dark gray symbols with black outline), respiratory rate (black symbols), FRC per weight (light gray symbols without outline) and LCI (white symbols) between groups.

<p>a) ROC curve comparing the ability of above mentioned lung function parameters to discriminate between healthy infants (term-born and preterm) and BPD infants using data of 221 healthy and 103 preterm infants. The resulting area under the curve is 0.58 for FRC_ao, 0.52 for LCI, 0.67 for respiratory rate and 0.76 for <i>t</i>_PTEF/<i>t</i>_E. b) ROC curve comparing the ability of above mentioned lung function parameters to discriminate between 179 term-born and 43 preterm healthy infants; BPD infants were not considered for this analysis. The resulting area under the curve is 0.43 for FRC_ao, 0.50 for LCI, 0.60 for respiratory rate and 0.64 for <i>t</i>_PTEF/<i>t</i>_E.</p

Box plots of the respective lung function values by subject groups.

<p>Subjects were grouped according to post-conceptional age at birth (term-born and preterm) and according to disease state based on ATS definition of BPD (healthy preterm, mild, moderate and severe BPD) <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0004635#pone.0004635-Jobe1" target="_blank">[6]</a>. The boxes indicate the median and the 25^th and 75^th percentile, the whiskers the upper and lower adjacent values. Outside values are shown as separate dots. Box plots are shown for lung clearance index (LCI).</p

Box plots of the respective lung function values by subject groups.

<p>Subjects were grouped according to post-conceptional age at birth (term-born and preterm) and according to disease state based on ATS definition of BPD (healthy preterm, mild, moderate and severe BPD) <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0004635#pone.0004635-Jobe1" target="_blank">[6]</a>. The boxes indicate the median and the 25^th and 75^th percentile, the whiskers the upper and lower adjacent values. Outside values are shown as separate dots. Box plots are shown for <i>t</i>_PTEF/<i>t</i>_E. The p-value for trend obtained by regression analysis was <0.001.</p

Figure 5

<p>a) Tidal volume versus weight for term and preterm infants. The black line indicates the regression line with a coefficient of correlation of 0.31 for the term-born infants and a coefficient of correlation of 0.65 for the preterm infants and the respective R² values given in the figure. b) Variability in lung volume determined by weight depending on disease severity. The graph shows 1−R² value of the regression model between weight and FRC. The R² value indicates how much of the variability in lung volume can be explained by the weight, and thus the 1−R² is a measure of how much infants are able to change their lung volumes given their body size.</p