Treatment of presumed hypotension in very low birthweight neonates: effects on regional cerebral oxygenation.
BACKGROUND
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.


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.


CONCLUSIONS
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.
Department of Pediatrics, University of Arizona, Tucson, Arizona, USA.
Rachel S
RS
Garner
David J
DJ
Burchfield
D001794:Blood Pressure / Q000502:physiology; D001921:Brain / Q000378:metabolism; D002245:Carbon Dioxide / Q000097:blood; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D006801:Humans; D007022:Hypotension / Q000503:physiopathology / Q000628:therapy*; D007231:Infant, Newborn; D007234:Infant, Premature; D007235:Infant, Premature, Diseases / Q000503:physiopathology / Q000628:therapy*; D019102:Infant, Very Low Birth Weight; D008297:Male; D010100:Oxygen / Q000097:blood; D010313:Partial Pressure; D016896:Treatment Outcome
D002245:Carbon Dioxide; D010100:Oxygen