Reliability of non-invasive blood pressure monitoring in sick very low birth weight preterm infants

Background Accurate blood pressure (BP) measurement is crucial for assessing hemodynamic features in infants with very low birth weight (VLBW). Various methods are available to monitor BP, including both invasive arterial blood pressure (IBP) and non-invasive blood pressure (NIBP). IBP monitoring, although accurate, poses risks due to its invasive approach, while NIBP monitoring, despite being safer, may lack precision. Objective To evaluate the agreement between IBP and NIBP measurements and assess the reliability of NIBP in diagnosing hypotension among VLBW infants. Methods This study was conducted in the neonatal intensive care unit (NICU) of King Fahd Armed Forces Hospital, Jeddah, Saudi Arabia. VLBW infants (n = 40) with IBP measured via an umbilical arterial catheter (UAC) or peripheral arterial line (PAL) were included. Simultaneous NIBP measurements were taken using appropriately sized cuffs. Results Across 3260 paired measurements, NIBP showed a mean bias of −6 ± 10 mmHg compared to IBP, with 95% limits of agreement from −25.6 to 13.6 mmHg. NIBP overestimated systolic, diastolic, and mean arterial pressures (MAP) by 8.9 mmHg, 7.47 mmHg, and 6.76 mmHg, respectively (all p < 0.001). Overall, 58% of pairs exceeded ±15% of invasive MAP. Invasive hypotension prevalence was 4.3% (MAP < gestational age) and 21.7% (MAP <30 mmHg). Receiver operating characteristics analysis showed modest diagnostic accuracy of NIBP (area under the curve = 0.627 and 0.707), with specificity >90% but sensitivity only 26.6%. Conclusions NIBP overestimates blood pressure, and IBP is the gold standard method for accurate BP assessment in VLBW infants.