Context Previous studies have correlated poor neurological outcomes with hypotension. Treatment of hypotension in very low birthweight (VLBW) infants is common, and most often is based solely on the blood pressure measurement. Whether treatment improves cerebral oxygenation is unclear.
Objective To determine if treatment of hypotension in VLBW neonates results in an increase in cerebral oxygenation.
Patients and methods In this single centre observational study, neonates <30 weeks and <1500 grams, blood pressure and regional cerebral oximetry (rCSO2) with near infrared spectroscopy were continuously monitored and digitally recorded. If patients were treated for hypotension during the first 3 days of life, effects of treatment on blood pressure and regional cerebral saturation were determined.
Results Twenty-eight of 50 patients were treated by the medical team for hypotension, of which 22 had accurate data recorded for analysis. Both normal saline 10 ml/kg, and dopamine 2.5–5 mcg/kg per min significantly increased blood pressure, (saline 26.8±3.5 to 28.8±4.2 mm Hg, p<0.005; dopamine 27.6±1.9 to 29.5±3.2 mm Hg, p<0.02). Pre-treatment values of rCSO2 were similar to published normative values and treatment with either normal saline or dopamine had no effect on rCSO2.
Conclusion These results suggest that treating hypotension in VLBW neonates based solely on a blood pressure measurement of less than 30 mm Hg, while increasing blood pressure, may not increase cerebral oxygenation, possibly because many of these patients are in the autoregulatory zone for cerebral blood flow.
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Funding Dr Garner was supported by a grant from the American Heart Association.
Competing interests Dr Burchfield obtained equipment used in the study from Somanetics, Inc, a company that has subsequently been purchased by Covidian, Inc. Neither Somanetics, Inc nor Covidian, Inc had a role in the design, data analysis or manuscript preparation of the submitted research.
Ethics approval University of Florida IRB.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement Minute-by-minute recordings of physiological variables for the first 3 days of life, in database format.