Ear/~ Human Development, 13 (1986) 343-350 Elsevier 343 of papers presented Abstracts at the Neonatal Society Meeting February 20,1986 London, U.K. Acute effects of indomethacin on neonatal cerebral blood velocities. F.M. Cowan, Department of Paediatrics, Ullevll Hospital, Oslo, and Department of Physiology, University of Oslo, Norway. Indomethacin, an inhibitor of cycle-oxygenase activity, has been shown to reduce cerebral blood flow in human adults by 40-50% and more in the presence of hypercapnoea. The acute effects of this drug have not been studied in the neonate. I have measured cerebral arterial blood velocities in 3 preterm infants with patent ductus arteriosus, using pulsed Doppler ultrasound (with online auditory and visual feedback of the signal) continuously, before, during and for 13 min after the intravenous infusion of indomethacin (0.2 mg/kg). A 6 MHz probe was held over the anterior fontanelle and not moved once an optimal signal had been obtained from one intracerebral artery. In all three infants blood velocities (time averaged mean blood velocities obtained by fast Fourier transform computer analysis of the signal, assuming an angle of insonication of 45”) fell sharply by 758, 57% and 488, respectively. There followed a period of relative stability but by 3 min postinjection the velocities started to rise reaching 59%, 72% and 90% of preinjection levels by 10 min. Transcutaneous 0, and CO, levels and blood pressure did not alter significantly. This large and sudden fall in velocities found almost certainly reflects a significant fall in cerebral blood flow. There has been no evidence that indomethacin increases cerebral blood flow. These results need to be investigated further but they emphasize the importance of maintaining adequate oxygenation and cerebral perfusion pressure when using this drug. The effect of hypoxia and ischaemia on cerebral blood flow and brain energy metabolism in the lamb. P.L. Hope, R.F. Aldridge, E.B. Cady, A.C.M. Chu, D.T. Delpy, R.M. Gardiner and E.O.R. Reynolds, Departments of Paediatrics, and Medical Physics and Bioengineering, University College London, London WClE 655, U.K. Seven episodes of cerebral hypoxia-ischaemia were studied in 6 mechanically ventilated lambs under barbiturate anaesthesia. Brain glucose and oxygen consumption, and lactate accumula- tion, were calculated from arterio-cerebral venous differences, and cerebral blood flow was measured by a hydrogen clearance technique. Nuclear magnetic resonance spectroscopy (NMRS) was carried out at a field strength of 1.89 tesla using a radio frequency surface coil 0378-3782/86/$03.50 0 1986 Elsevier Science Publishers B.V. (Biomedical Division)

Acute effects of indomethacin on neonatal cerebral blood velocities : F.M. Cowan, Department of Paediatrics, Ullevål Hospital, Oslo, and Department of Physiology, University of Oslo,

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Page 1: Acute effects of indomethacin on neonatal cerebral blood velocities : F.M. Cowan, Department of Paediatrics, Ullevål Hospital, Oslo, and Department of Physiology, University of Oslo,

Ear/~ Human Development, 13 (1986) 343-350 Elsevier

343

of papers presented

Abstracts

at the Neonatal Society Meeting February 20,1986

London, U.K.

Acute effects of indomethacin on neonatal cerebral blood velocities. F.M. Cowan, Department of Paediatrics, Ullevll Hospital, Oslo, and Department of Physiology, University of Oslo, Norway.

Indomethacin, an inhibitor of cycle-oxygenase activity, has been shown to reduce cerebral blood flow in human adults by 40-50% and more in the presence of hypercapnoea. The acute effects of this drug have not been studied in the neonate. I have measured cerebral arterial blood velocities in 3 preterm infants with patent ductus arteriosus, using pulsed Doppler ultrasound (with online auditory and visual feedback of the signal) continuously, before, during and for 13 min after the intravenous infusion of indomethacin (0.2 mg/kg). A 6 MHz probe was held over the anterior fontanelle and not moved once an optimal signal had been obtained from one intracerebral artery. In all three infants blood velocities (time averaged mean blood velocities obtained by fast Fourier transform computer analysis of the signal, assuming an angle of insonication of 45”) fell sharply by 758, 57% and 488, respectively. There followed a period of relative stability but by 3 min postinjection the velocities started to rise reaching 59%, 72% and 90% of preinjection levels by 10 min. Transcutaneous 0, and CO, levels and blood pressure did not alter significantly. This large and sudden fall in velocities found almost certainly reflects a significant fall in cerebral blood flow. There has been no evidence that indomethacin increases cerebral blood flow. These results need to be investigated further but they emphasize the importance of maintaining adequate oxygenation and cerebral perfusion pressure when using this drug.

The effect of hypoxia and ischaemia on cerebral blood flow and brain energy metabolism in the lamb. P.L. Hope, R.F. Aldridge, E.B. Cady, A.C.M. Chu, D.T. Delpy, R.M. Gardiner and E.O.R. Reynolds, Departments of Paediatrics, and Medical Physics and Bioengineering, University College London, London WClE 655, U.K.

Seven episodes of cerebral hypoxia-ischaemia were studied in 6 mechanically ventilated lambs under barbiturate anaesthesia. Brain glucose and oxygen consumption, and lactate accumula- tion, were calculated from arterio-cerebral venous differences, and cerebral blood flow was measured by a hydrogen clearance technique. Nuclear magnetic resonance spectroscopy (NMRS) was carried out at a field strength of 1.89 tesla using a radio frequency surface coil

0378-3782/86/$03.50 0 1986 Elsevier Science Publishers B.V. (Biomedical Division)