Noninvasive Continuous Arterial Blood Pressure Monitoring with Nexfin

Anesthesiology, 04/26/2012

Martina JR et al. – Arterial blood pressure can be measured noninvasively and continuously using physiologic pressure reconstruction. Changes in pressure can be followed and values are comparable to invasive monitoring.

Methods

  • Intra-arterial pressure (IAP) and noninvasive Nexfin arterial pressure (NAP) were measured in cardiothoracic surgery patients, because invasive pressures are available.
  • NAP-IAP differences were analyzed during 30min.
  • Tracking was quantified by within-subject precision (SD of individual NAP-IAP differences) and correlation coefficients.
  • The ranges of pressure change were quantified by within-subject variability (SD of individual averages of NAP and IAP).
  • Accuracy and precision were expressed as group average ±SD of the differences and considered acceptable when smaller than 5±8mmHg, the Association for the Advancement of Medical Instrumentation criteria.

Results

  • NAP and IAP were obtained in 50 (34-83 yr, 40 men) patients.
  • For systolic, diastolic, mean arterial, and pulse pressure, median (25-75 percentiles) correlation coefficients were 0.96 (0.91-0.98), 0.93 (0.87-0.96), 0.96 (0.90-0.97), and 0.94 (0.85-0.98), respectively.
  • Within-subject precisions were 4±2, 3±1, 3±2, and 3±2mmHg, and within-subject variations 13±6, 6±3, 9±4, and 7±4mmHg, indicating precision over a wide range of pressures.
  • Group average ±SD of the NAP-IAP differences were -1±7, 3±6, 2±6, and -3±4mmHg, meeting criteria.
  • Differences were not related to mean arterial pressure or heart rate.

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