Effect of intubation and mechanical ventilation on exhaled nitric oxide in preterm infants with and without bronchopulmonary dysplasia measured at a median postmenstrual age of 49 weeks

Table 2 Spearman rank order coefficients of eNO and V’ _NO with patient characteristics at birth and at day of measurements and lung function parameters

	eNO (ppb)		V’NO (nL/s)
	R _s	p-value	R _s	p-value
Patient data at day of birth
Gestational age (weeks)	-0.103	0.176	-0.058	0.447
Birth weight (g)	-0.105	0.167	-0.045	0.555
Birth weight Z-score	0.033	0.666	0.049	0.515
Patient data at day of measurement
Age (days)	0.031	0.682	0.264	<0.001
PMA (weeks)	-0.007	0.926	0.237	0.002
Body weight (g)	-0.033	0.655	0.210	0.006
Body length (cm)	0.002	0.985	0.250	0.001
Tidal breathing
V_T (mL/kg)	0.011	0.883	0.151	0.047
RR (1/min)	-0.216	0.004	-0.266	<0.001
V’_E (mL/min/kg)	-0.228	0.003	-0.170	0.025
t_ptef/t_e (%)	-0.110	0.148	-0.113	0.135
t_e (s)	0.274	<0.001	0.281	<0.001
PTIF (mL/s/kg)	-0.062	0.415	-0.083	0.272
PTEF (mL/s/kg)	-0.230	0.002	-0.163	0.032
MTIF (mL/s/kg)	-0.121	0.112	-0.107	0.158
MTEF (mL/s/kg)	-0.274	<0.001	-0.192	0.011
Respiratory mechanics
C_rs (mL/kPa/kg)	-0.027	0.725	0.058	0.450
R_rs (kPa/L/s)	0.078	0.318	-0.162	0.037
Blood gas analysis
paO₂ (mmHg)	-0.059	0.434	0.147	0.053
paCO₂ (mmHg)	0.158	0.037	-0.037	0.628

R_s, Spearman rank order correlation coefficient, statistically significant values after Bonferroni correction (p < 0.0025) are shown in boldface.
Abbreviations: PMA - postmenstrual age, V_T - tidal volume, RR - respiratory rate, V’_E- minute ventilation, t_ptef/t_e - ratio of time to peak tidal expiratory flow to expiratory time, t_e - expiratory time, PTIF - peak tidal inspiratory flow, PTEF - peak tidal expiratory flow, MTIF - mean tidal inspiratory flow, MTEF - mean tidal expiratory flow, C_rs - respiratory compliance, R_rs - respiratory resistance.

ISSN: 1756-0500