Comparison of non-invasive vs invasive blood pressure measurement in neonates undergoing therapeutic hypothermia for hypoxic ischemic encephalopathy.

Abstract

To evaluate the accuracy of blood pressure (BP) measured non-invasively (NIBP) compared with invasive arterial BP (IABP) measured by umbilical arterial catheter in neonates undergoing therapeutic hypothermia (TH) for hypoxic ischemic encephalopathy (HIE). We conducted a retrospective study of neonates with gestational age (GA)⩾35 weeks with HIE who received TH. Paired NIBP and IABP measurements were obtained during TH and during normothermia. We collected 897 paired measurements from 40 infants, which included 623 pairs during TH and 274 pairs during normothermia. The mean±s.d. differences in BP measured by NIBP compared with IABP in mmHg were -0.2±8.8 (P=0.505) for systolic BP (SBP), -4.5±8.3 (P<0.001) for diastolic BP (DBP) and -5.1±7.5 (P<0.001) for mean BP (MBP) during TH; and -1.3±9.2 (P=0.016) for SBP, -7.5±7.8 (P<0.001) for DBP and -7.3±6.8 (P<0.001) for MBP during normothermia. Overall 466/623 (74.8%), 324/623 (52.0%) and 363/623 (58.3%) of NIBP measurements of SBP, DBP and MBP, respectively, were clinically acceptable (defined as difference ⩽15% of IABP reading) during TH; and 202/274 (73.7%), 118/274 (43.1%) and 148/274 (54.0%), were clinically acceptable during normothermia. In term or near-term neonates with HIE, NIBP measurements are a robust method to determine SBP; however, DBP and MBP are underestimated. Determination of hypotension using the MBP measured non-invasively should be interpreted with caution.