Eliminating Noise in a Cerebral Function Monitor Signal Group 14 Brian Snelling, JP Day, Colin Compas

Project Description Cerebral Functioning Monitor EEG Reading Affected Machine Leads EEG Reading Affected EMI ECG Physical Contact Equipment Proximity

Device Description Cerebral Function Monitor Continuously measures brain activity Normal reading Between 10-40 μV Impedance - Less than 20k ohms Detects Oxygen loss (HIE) Drug side effects Seizures Used approx. once per month

Solutions Move other equipment Remove ECG signal Shield Device Frequencies too high Proximity Remove ECG signal Ranges Overlap Shield Device CFM is Licensed and Approved Device Already has Shield Shield Leads Preliminary Testing Options

CFM Tracings EMI can lead a normal signal to resemble the abnormal signal which can lead to misdiagnosis of a baby’s cognitive function. Normal tracing characterized by central band in the 10-40µV range with a normal sleep wake cycle Abnormal tracing characterized by lower, narrow band of activity with spikes indicating burst suppression Normal tracing affected by EMI

Phantom Scans Phantom was a cantaloupe with a diameter of 14 in. and a weight of 2 lb. 4 oz. Phantom test 1 Phantom test 2

Distance Data Noise values measured (µV) for 3-D distances of Medfusion Syringe and Fusion Pump for the shown experimental design.

Initial Shield Initial shield was copper hot water heater tube. Eliminated all noise seen in unshielded wires. Now looking into acquiring medical grade copper shielding that can be used in the NICU.

Misdiagnosis Baby in need of treatment due to CNS injury due to hypoxia but the CFM reading is persistently over 10 µV and appears normal, disqualifying the baby for therapy Failure to prevent brain injury Baby with no brain activity but in whom interference generates a wave The baby is actually too severely injured to benefit from cooling yet because of a false signal would be cooled

Completed Work Isolated noise signal with melon Collected Data Used Medfusion Pump Eliminated Noise Signal Copper Tube Crude Device Contacted Ted Weiler Head of R & D Ruled out EMI causes Will review our data Generated 3D noise graph

Current Work Obtain medical grade copper mesh Contact Dr. Wikswo Characterize noise signal Use signal generator Work w/ Clinical Eng. Department Contact Olympic Medical Discuss lead shielding Obtain list of “problem” devices Dr. Walsh Olympic Medical Test other “problem” devices Record noise signals

Future Work Rerun noise test with medical grade copper mesh shield Use shield with signal generator to control output signal Insulate copper mesh shield Implement system in incubator Test in NICU setting Continue working w/ Olympic Medical

References Vries L, Hellstrom-Westas L. Role of cerebral function monitoring in the newborn. Archives of Disease in Childhood, 2007;27. Spitzer A. Neonatal Cerebral Function Monitoring. Neonatalogy Today, 2006;1:1-12. Gluckman P, Wyatt J, et al. Selective head cooling with mild systemic hypothermia after neonatal encephalopathy: multi-centre randomized trial. Lancet. 2005;365:663-70. al Naqeeb N, Edwards AD, Cowan FM, Azzopardi D. Assessment of neonatal encephalopathy by amplitude integrated electroencephalography. Pediatrics 1999; 103(6):1263–1271. Archbald F, Verma UL, Tejani NA, Handwerker SM. Cerebral function monitor in the neonate. II: Birth asphyxia. Dev Med Child Neurol 1984; 26(2):162–168. Greisen G. Tape-recorded EEG and the cerebral function monitor: amplitude-integrated, time-compressed EEG. J Perinat Med 1994; 22(6):541–546. Thornberg E, Thiringer K. Normal pattern of the cerebral function monitor trace in term and preterm neonates. Acta Paediatr Scand 1990; 79(1):20–25. Verma UL, Archbald F, Tejani NA, Handwerker SM. Cerebral function monitor in the neonate. I: Normal patterns. Dev Med Child Neurol 1984; 26(2):154–161.