439 - Does Elevated Midline Head Position in Periviable Lambs Alter Hemodynamic Response to Surfactant?

Poster Number: 439
Publication Number: 439.227

Andreina Mari, Jacobs School of Medicine and Biomedical Sciences at the University at Buffalo, Depew, NY, United States; Mausma Bawa, Jacobs School of Medicine and Biomedical Sciences at the University at Buffalo, Buffalo, NY, United States; Sylvia Gugino, SUNY at Buffalo, Buffalo, NY, United States; Justin Helman, Jacobs School of Medicine and Biomedical Sciences at the University at Buffalo, Bufalo, NY, United States; Nicole Bradley, Jacobs School of Medicine and Biomedical Sciences at the University at Buffalo, Buffalo, NY, United States; Carmon Koenigsknecht, Canon Stroke and Vascular Research Center, Buffalo, NY, United States; Arun Prasath, Jacobs School of Medicine and Biomedical Sciences at the University at Buffalo, Williamsville, NY, United States; Praveen Chandrasekharan, Jacobs School of Medicine and Biomedical Sciences at the University at Buffalo, Buffalo, NY, United States; Munmun Rawat, University at Buffalo, Buffalo, NY, United States; Jayasree Nair, Jacobs School of Medicine and Biomedical Sciences at the University at Buffalo, Buffalo, NY, United States

Background: Surfactant administration (Surf) may cause variable changes in cerebral hemodynamics such as an increase (Saliba,1994; Rabe,1991) or decrease in cerebral blood flow (Cowan, 1991) and pulmonary artery pressure (Hamdan,1995). Differences in timing/type of Surf and exposure to antenatal steroids also may be contributing factors (Katheria,2013). Lack of autoregulation in ELBW infants predisposes to swings in cerebral blood pressure (BP) which may contribute to intraventricular hemorrhage (IVH). Elevated head positioning (EMHP) after admission to the NICU may decrease severe IVH, improve oxygenation and survival (Kochan,2019). We hypothesized that EMHP during Surf in a periviable ovine model would decrease hemodynamic fluctuation and improve cerebral oxygen delivery (DO2).

Objective: 1.To evaluate the effect of 15° EMHP during Surf on BP, carotid (CBF) & pulmonary (PBF) blood flow and DO2 in a periviable ovine model.

Design/Methods: 120d gestation beta-mature lambs, were randomized into elevated (ELEV: 15° elevation) or standard group (FLAT). Lambs were resuscitated per NRP guidelines with delayed cord clamping and initial FiO2 of 0.3. 3ml/kg of intratracheal Surf was administered after 5 min. PBF, CBF, BP, HR, and pulse oximetry (SpO2) were monitored continuously using Biopac and Nonin systems. Blood gases were collected before and after Surf. Graphpad PRISM software was used for statistical analysis using appropriate tests.

Results: Baseline characteristics were similar (Table 1). There was no significant difference in CBF with Surf (Fig 1a). PBF was significantly higher in the ELEV group around Surf. Slight increase in PBF after Surf was seen in both groups (Fig 1b). BP (Fig 1c) was similar between groups. DO2 went up post Surf in both groups, but the response was similar in FLAT and ELEV (Fig 1d).Conclusion(s): In our model, EMHP during Surf improved PBF but had no significant effect on systemic hemodynamics. While reduced pulmonary vascular resistance and increased ductal left-to-right shunting after Surf may improve PBF and DO2 in both groups, we speculate that improved ventilation of the lungs and better Qp:Qs matching with ELEV contributes to significantly higher PBF. Further human studies of hemodynamics during Surf in ELEV are needed to assess benefits.
Table 1: Baseline Demographics
Figure 1: Hemodynamics and oxygen delivery during surfactant administrationBlue bar represents approximate period of surf administration. 1a) CBF b) PBF c) MBP and d) oxygen delivery in the two groups are represented.