title: Umbilical catheters and arterial blood pressure monitoring.
abstract: The natural frequencies, damping coefficients, and accuracies of umbilical artery catheters were determined. The damping coefficients for the 3.5, 5.0, and 8.0 French catheters were 0.40 +/- 0.04 (mean +/- SD), 0.42 +/- 0.05, and 0.19 +/- 0.02, respectively. The natural frequencies were 24.2 +/- 3.2 Hz (mean +/- SD), 18.4 +/- 3.5 Hz, and 26.8 +/- 2.9 Hz, respectively. Measurements obtained with 3.5 and 8.0 French catheters were within 6% of the reference pressure at all pressures and rates tested. With the 5.0 French catheter, however, error greater than 10% from the reference pressure occurred when the rate was 200 pulses per minute or greater and the applied maximum pressure was 100 mm Hg or more.
mesh_terms: D001794:Blood Pressure; D001795:Blood Pressure Determination / Q000295:instrumentation*; D002404:Catheterization / Q000295:instrumentation*; D005069:Evaluation Studies as Topic; D006801:Humans; D008991:Monitoring, Physiologic / Q000295:instrumentation; D014469:Umbilical Arteries / Q000502:physiology*