The feasibility of noninvasive blood pressure monitoring in infants with a birth weight under 500 grams.

OBJECTIVE

To quantify agreement between oscillometric non-invasive blood pressure (NIBP) and invasive arterial blood pressure (IBP) in infants <500 g during the first postnatal week.

STUDY DESIGN

Retrospective cohort of infants with a birth weight <500 g admitted to a tertiary NICU (2011-2023). Paired IBP-NIBP readings obtained within 1 min were analyzed. Bland-Altman plots quantified bias and 95% limits of agreement for systolic (SBP), diastolic (DBP) and mean arterial pressure (MAP).

RESULTS

Thirty-six infants (median gestation of 26.2 weeks) contributed 337 paired measurements. Mean (±SD) IBP vs. NIBP were 47.3  ±  10.4 vs. 49.4  ±  9.3 mm Hg (SBP), 29.2  ±  7.0 vs. 28.3  ±  8.2 mm Hg (DBP) and 35.1  ±  7.7 vs. 35.2  ±  7.9 mm Hg (MAP). Mean bias was +2.1 ±  6.8 mm Hg (SBP), -0.9  ±  6.7 mm Hg (DBP) and +0.1 ± 5.4 mm Hg (MAP), satisfying AAMI/ESH/ISO criteria (≤5 mm Hg mean difference, ≤8 mm Hg SD). Bias remained <3 mm Hg without inotropes; MAP bias rose to +1.3 mm Hg with inotropic support.

CONCLUSION

Oscillometric NIBP compared to IBP provided acceptable agreement in hemodynamically stable neonates <500 g. Whereas, invasive arterial monitoring remains preferable in unstable neonates.