Syngo dynamics workstation

Csat and Rsat levels were measured using the INVOS 5100 NIRS monitor (Medtronic, Minneapolis, MN). As previously described by our group [9 (link), 11 (link)], neonatal sensors were routinely applied shortly after birth on the central forehead and on either the right or left posterior flank above the iliac crest and below the costal margin (T10-L2) [11 (link)]. Csat and Rsat were extracted from our NIRS database, which contains prospectively collected NIRS values recorded at 30 s intervals. Systemic saturation (SpO2) values at the beginning of the ECHO were collected from nursing flowsheets. ECHO scans were stored on the picture archiving and communication system (PACS). Time at the start of the ECHO was retrieved from the images stored on the Syngo Dynamics workstation (Siemens Medical Solutions, USA). The Csat and Rsat values in the hour before and after the start of the ECHO were averaged. Cerebral and renal fractional tissue oxygen extraction (cFTOE and rFTOE, respectively), calculated as (SpO2 – [Csat or Rsat])/SpO2, was similarly collected as a measure of oxygen extraction by the brain or kidneys [3 (link)]. Clinicians were not blinded to Csat and Rsat levels, but no management guidelines based on NIRS values were in place other than notification of a medical provider if Csats were sustained < 50%.

Echocardiographic data was obtained using a Phillips iE33 system with the S5-1 transthoracic probe (Koninklijke Philips NV, Amsterdam, The Netherlands) for short- and long-axis views and color flow mappings. Continuous-wave doppler was also recorded. Data analysis was performed using the iE33 on-board software and a Siemens Syngo Dynamics workstation (Siemens Medical Solutions USA, Inc., Ann Arbor, MI).