299 - Assessing the feasibility of a non-invasive continuous arterial blood pressure cuff in a high-risk neonatal population.

Poster Number: 299
Publication Number: 299.441

Brooke A. Krbec, Boston Children's Hospital, West Roxbury, MA, United States; Fan-Yu Yen, National Cheng Kung University, Tainan, Tainan, Taiwan (Republic of China); Taylor A. Vadset, Boston Children's Hospital, Brookline, MA, United States; Rachel Lippman, Boston Children's Hospital, Boston, MA, United States; Michael J. Woglom, Boston Children's Hospital, Boston, MA, United States; Patricia Ellen Grant, Boston Children's Hospital, Boston, MA, United States; Jason Sutin, Boston Children's Hospital, Boson, MA, United States; Pei-Yi Lin, Boston Children's Hospital, Boston, MA, United States

Background: Options for measuring continuous arterial blood pressure (ABP) are limited in the neonatal population and requires invasive catheterization that can lead to life-threatening complications. Due to the lack of non-invasive devices for ABP monitoring, arterial lines remain the gold standard.

Objective: Assess the feasibility of a non-invasive BP device, the Finapres® (FP) in a high-risk neonatal population to ultimately provide a safe, bedside alternative to invasive ABP monitoring.®

Design/Methods: Observational, prospective cohort study of 30 infants < 6 months PMA, >1kg with an a-line, admitted to the NICU at Boston Children’s Hospital. All infants were screened for contraindications to non-invasive cuff placement, and once enrolled had an appropriately sized FP cuff selected and placed around either the infant’s wrist or ankle. Cuff measurements were performed cyclically with insufflation of the cuff for 2-minutes followed by 2-4 minutes of rest for 8-10 cycles both with the physiocalibration (PSK) function turned off and on. Continuous beat-to-beat BP data, including systolic BP, diastolic BP and mean arterial BP were recorded from the a-line and from the FP. Trends of the FP waveforms from the first 10 study subjects were qualitatively compared to the a-line waveform and were analyzed.

Results: FP measurements with PSK disabled revealed progressive diminished waveforms throughout the insufflation cycle. A polynomial detrend function was utilized to correct for the both the downtrend in the baseline and the reduction in amplitude of the waveform over time. Overall, this corrected for the baseline, but did not adjust for the loss of amplitude. Measurements with PSK enabled demonstrated no loss in the quality of the waveform, however a 1-minute period following initial calibration as well as intermittent interruptions of the waveform from active PSK adjustments rendered unreliable data. Calibration periods were eliminated by building a model using thresholds where the lower trough of the waveform (representing diastolic) was smaller than the upper peak of the waveform (representing systolic). The magnitude difference and the difference in time duration between the peaks and troughs were calculated to eliminate unusable data. Other variables also affected the quality of the waveform data including: fit of the cuff, location of light sensors and patient perfusion.Conclusion(s): Comparison of the waveforms has demonstrated that the FP device may be a reliable alternative to invasive ABP monitoring, but adjustments to our validation study are necessary to demonstrate clinical utility.