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Comparison of Continuous Non-invasive Arterial Pressure (CNAP) With Invasive Arterial Pressure Monitoring

This study has been completed.
Information provided by (Responsible Party):
Robert Hanss, University of Schleswig-Holstein Identifier:
First received: October 28, 2009
Last updated: April 13, 2012
Last verified: April 2012

The purpose of this study was to compare the Continuous Non-invasive Arterial Pressure (CNAP) monitor with the gold standard of invasive arterial pressure monitoring during:

  1. induction and maintenance of general anaesthesia
  2. intensive care unit treatment of postoperative patients with an ASA 3 or 4 status

Blood Pressure

Study Type: Observational
Study Design: Observational Model: Case Control
Time Perspective: Prospective
Official Title: Accuracy of the CNAP™ Monitor (Continuous Non-invasive Arterial Pressure) Versus Invasive Radial Arterial Monitoring in Surgical Patients

Further study details as provided by Robert Hanss, University of Schleswig-Holstein:

Primary Outcome Measures:
  • Bias and percentage error of CNAP compared with invasive arterial pressure measurement [ Time Frame: 1.) Induction of general anaesthesia. 2.) Maintanance of general anaesthesia. 3.) Intensive Care Treatement after surgery ]

Enrollment: 195
Study Start Date: February 2009
Study Completion Date: January 2012
Primary Completion Date: May 2010 (Final data collection date for primary outcome measure)
Intensive Care treatement
ASA status 3 or 4 patients with invasive blood pressure measurement on the intensive care unit

Detailed Description:

The CNAP monitor continuously measures blood pressure using a finger cuff. It showed a good agreement to invasive blood pressure measurements during anaesthesia induction and maintenance during surgery. In critical ill patients cardiac arrhythmia is probably a confounding factor affecting accuracy and interchangeability of CNAP. As systolic arterial CNAP pressure in comparison to mean pressure shows no statistical interchangeability with invasive measurements, mean pressure should be considered when making therapy decisions.

A problem is the missing standard criterion for comparison of continuously devices with invasive pressure.


Ages Eligible for Study:   18 Years and older   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Sampling Method:   Probability Sample
Study Population
patients undergoing major surgery or intensive care unit treatement with the need for an invasive blood pressure measurement

Inclusion Criteria:

  • Age >18
  • BMI < 35 kg.m²
  • Patients capable of giving informed consent
  • patients undergoing elective surgical procedures in supine position under general anesthesia
  • perfusion of the examined arm evidenced by a positive Allen's test

Exclusion Criteria:

  • Patients not competent or unwilling to provide informed consent
  • Patients with history of neurological, neuromuscular seizure
  • Patients where IBP cannula, CNAP™ finger-cuff and CNAP™ upper arm cuff cannot be placed on the same arm
  Contacts and Locations
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Please refer to this study by its identifier: NCT01003665

Klinik für Anästhesiologie und Operative Intensivmedizin, Universitätsklinik Schleswig-Holstein, Campus Kiel
Kiel, Germany, 24106
Sponsors and Collaborators
University of Schleswig-Holstein
Study Chair: Markus Steinfath, Professor Klinik für Anästhesiologie und Operative Intensivmedizin, UKSH Kiel
Study Director: Robert Hanss, Professor Klinik für Anästhesiologie und Operative Intensivmedizin, UKSH Kiel