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OBJECTIVE: Persistent pulmonary hypertension of the newborn (PPHN) is a serious cardiorespiratory problem. PPHN is frequently associated with refractory hypoxia and hypotension, and optimal management has the potential to improve important clinical outcomes including mortality. The primary objective is to evaluate the efficacy and safety of rescue vasopressin (VP) therapy in the management of severe (refractory) hypoxia and refractory systemic hypotension in term neonates with severe PPHN. STUDY DESIGN: Neonates with refractory hypoxia and refractory hypotension due to severe PPHN needing VP were prospectively enrolled in the study. Refractory hypoxia was defined as oxygenation index (OI) ≥ 25 for at least 4 hours after the commencement of high-frequency oscillatory ventilation and nitric oxide at 20 ppm. Refractory hypotension was defined as mean blood pressure lesser than mean gestational age lasting for more than 15 minutes in spite of dopamine infusion at 10 µg/kg/min, adrenaline infusion at 0.3 µg/kg/min, and noradrenaline infusion at 0.1 µg/kg/min. RESULTS: Thirty-two neonates with PPHN were recruited. The baseline OI (mean ± standard deviation [SD]) before starting VP was 33.43 ± 16.54 which started decreasing significantly between 1 and 6 hours after the commencement of VP (p < 0.05). The mean blood pressure also increased concomitantly with a significant effect seen by 1 hour (p < 0.05). The vasoactive infusion score before the commencement of VP was mean 46.07 (SD = 25.72) and started decreasing after 12 to 24 hours of commencement of VP (p < 0.05). Lactate levels (mean ± SD) before starting VP were 7.8 ± 8.6 mmol/L and started decreasing between 6 and 12 hours (p < 0.05). Two neonates died due to refractory hypoxia and refractory hypotension (overall mortality 6.2%) CONCLUSION: Rescue VP therapy is a useful adjunct in the management of neonates with severe PPHN with refractory hypoxia and/or refractory hypotension. Improvement in oxygenation and hemodynamics with the use of VP results in reduced mortality. KEY POINTS: · Rescue vasopressin is a useful adjunct in the management of neonates with severe PPHN.. · Vasopressin helps reduce OI.. · Vasopressin reduces the vasoactive inotrope score..
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BACKGROUND: Accurate measurement of blood pressure (BP) is extremely important in the management of sick preterm newborns. The primary objective of this study was to compare non-invasive blood pressure measurement (NIBP) with invasive blood pressure measurement (IBP) using peripheral arterial cannulation (PAC) in preterm neonates < 37 weeks in the neonatal intensive care unit. METHODS: Preterm neonates needing PAC were prospectively enrolled in the study. NIBP measurements were taken in the same limb as that of peripheral arterial line. Initially IBP was recorded followed by NIBP within 1 min using the same monitor. These were called as paired measurements since they are taken within 1 min of each other. RESULTS: Seventy-three preterm infants with 1703 paired measurements were included in the final analysis (median gestational age 32 weeks, IQR 30-34 weeks, median birth weight 1540 g, IQR 1160-2100 g). In preterm infants not receiving vasoactive agents (n = 51, 1428 paired measurements, Bland-Altman analysis for agreement between invasive mean blood pressure (MBP) and non-invasive mean BP revealed a bias of -2.9123 mmHg (SD 7.8074). The 95% limits of agreement were from -18.2157 to 12.3893 mmHg. In preterm infants with hypotension, we detected a bias of -3.9176 mmHg (SD 5.1135) between invasive MBP and non-invasive MBP. The 95% limits of agreement were from -13.9401 to 6.1048 mmHg. In normotensive preterm infants receiving vasoactive agents, we detected a bias of -0.7629 mmHg (SD 8.0539) between invasive MBP and non-invasive MBP. The 95% limits of agreement were from -16.5485 to 15.02274 mmHg. CONCLUSIONS: There is poor level of agreement between IBP and NIBP measurements in sick preterm neonates, leading to overestimation or underestimation of blood pressure. The bias was less for mean BP measurements as compared with systolic BP measurements and also for normotensive neonates as compared with hypotensive neonates. Hence, NIBP may be used as a screening method in haemodynamically stable preterm infants, but infants who are haemodynamically unstable and need to be commenced on vasoactive agents should have IBP monitoring.