542 - NeoDoppler monitoring of cerebral blood flow during general anesthesia in infants

Poster Number: 542
Publication Number: 542.139

Sigrid Vik, St. Olavs University Hospital, Trondheim, Norway, Trondheim, Sor-Trondelag, Norway; Hans Torp, NTNU, Trondheim, Sor-Trondelag, Norway; Ragnhild Støen, Norwegian University of Scinence and Technology, Trondheim, Sor-Trondelag, Norway; Siri Ann Nyrnes, St. Olavs University Hospital/Norwegian University of Science and Technology, Trondheim, Sor-Trondelag, Norway

Background: General anesthesia is associated with neurocognitive deficits in young infants undergoing non-cardiac surgery. Cerebral hypoperfusion related to systemic hypotension and impaired autoregulation may lead to injuries in the immature brain.

Objective: We aimed to study cerebral blood flow velocities (CBFV) continuously during general anesthesia in infants undergoing non-cardiac surgery and relate variations in CBFV to simultaneously measured near-infrared spectroscopy (NIRS), blood pressure (BP) and heart rate (HR).

Design/Methods: CBFV was monitored with NeoDoppler via the anterior fontanel during induction and maintenance of general anesthesia before start of surgery, and during recovery. Simultaneous recordings of NIRS, BP and HR were obtained.

Results: Eighteen infants (13 boys) with median gestational age at birth 36.8 weeks (range 27.9-41.4) and median postmenstrual age at surgery 37.6 weeks (range 31.7-60) were included. Thirteen infants underwent major gastrointestinal surgery, and five infants underwent minor surgery. In 16 infants the trend curves showed a decrease in CBFV during induction of anesthesia compared with baseline (Fig 1). Intubation was followed by a short period with increased CBFV, before stabilizing at lower values and with less variations compared to baseline (Fig 1). End diastolic velocities (EDV) were significantly reduced compared to baseline values at the end of induction (mean 52%; range 15-99%) and remained reduced during anesthesia (mean 49%; range 15-95%) (Table 1 and Fig 2). During recovery, EDV returned to baseline values (Table 1 and Fig 2). Mean pulsatility index increased significantly to 157% (range 96-307) and 187% (range 100-254%) of baseline values during induction and maintenance of general anesthesia, respectively. Mean and diastolic arterial BP immediately before surgery was reduced to 79% (range 43-106%) and 80% (range 35-146%), respectively, of baseline values. NIRS and saturation values were high and remained stable during anesthesia (Table 1 and Fig 1).Conclusion(s): Continuous monitoring of CBFV during general anesthesia in infants showed significantly reduced EDV with a concomitant reduction in blood pressure. NeoDoppler may be a valuable tool to optimize cerebral perfusion during anesthesia and surgery in infants with an open fontanel.
Figure 1: Trend curve showing a characteristic pattern before, during and after anesthesia in one infant with duodenal atresia, gestational age 37 weeksCBFV=cerebral blood flow velocity, PSV= peak systolic velocity, TAV: time average velocity, EDV=end diastolic velocity, PSP=peak systolic pressure, MAP= mean arterial blood pressure, EDV= end diastolic velocity, Sp02= oxygen saturation, NIRS= near-infrared spectroscopy
Figure 2: Changes in Doppler waveforms before, during and after anesthesia