The use of inotropes does not change the agreement of invasive vs. non-invasive blood pressure in preterm neonates
Purpose: Blood pressure constitutes an important parameter in the assessment of the cardiovascular status in preterm infants. Invasive arterial blood pressure (IBP) is considered the „gold-standard“, but non-invasive blood pressure (NIBP) is used frequently in preterm infants. The aim of this prospective study was to assess the degree of agreement of mean IBP and mean NIBP arterial blood pressure measurements in 3 subsets of preterm infants (>1500 grams; 1000–1500 grams, and <1000 grams) with regard to the use of inotropes (dopamine, noradrenaline, adrenaline). Methods: Prospective, simultaneous assessment of IBP and NIBP measurements in 50 preterm neonates at 6h, 12h, 18h, 24h after birth in a tertiary University center. Results: Mean gestational age was 26.7±2.2 (24–32) in group I (n=18), 29.6±2.0 (27–34) in group II (n=19), and 32.2±1.9 (30–36) weeks in group III (n=13) respectively; mean birth weight was 777±161 (495–995), 1251±154 (1010–1490), and 2010±332 (1590–2550) grams. Mean IBP and mean NIBP increased significantly during the first 24h of life in all 3 sub-groups (p<0.01); IBP and NIBP measurements were significantly correlated, and showed good agreement, irrespective of birth weight, gestational age, and the use of inotropes (table 1). When looking at the use of inotropes and the 3 subgroups, the following correlations were found: Group I: r(6h) =0.678, p=0.005; r(12h)=0.588, p=0.035; r(18h)=0.567, p=0.043; r(24h)=0.741, p=0.004; Group II: r(6h)=0.219, p=0.571; r(12h)=0.134, p=0.730; r(18h)=0.820, p=0.004; r(24h)=0.382, p=0.321; Group III: r(6h)=numbers too small for correlation studies; r(12h)=0.975, p=0.005; r(12h)=0.500, p=0.391; r4=0.949, p=0.051. Conclusions: The use of inotropes does not modify the degree of agreement between IBP and NIBP measurements in preterm infants.