title: CNAP(®) does not reliably detect minimal or maximal arterial blood pressures during induction of anaesthesia and tracheal intubation.
abstract: BACKGROUND
  CNAP(®) provides continuous non-invasive arterial pressure (AP) monitoring. We assessed its ability to detect minimal and maximal APs during induction of general anaesthesia and tracheal intubation.
  
  
  METHODS
  Fifty-two patients undergoing surgery under general anaesthesia were enrolled. Invasive pressure monitoring was established at the radial artery, and CNAP monitoring using a finger sensor recording was begun before induction. Statistical analysis was conducted with the Bland-Altman method for comparison of repeated measures and intraclass correlation coefficient (ICC).
  
  
  RESULTS
  Patients' median age was 67 years [interquartile range (59-76)], median American Society of Anesthesiologists score was 3 [interquartile range (2-3)]. Bias was 5 and -7 mmHg for peak and nadir systolic AP (SAP), with upper and lower limits of agreement of (42:-32) and (27;-42), respectively. The corresponding ICC values were 0.74 [95% confidence interval (CI) = 0.57-0.84] and 0.60 (95% CI = 0.44-0.73). Time lags to reach these values were 7.5 s (95% CI = -10.0 to 60.0) for the highest SAP and 10 s (95% CI = -12.5 to 72.5) for the lowest SAP. Bias, lower and upper limits of agreement for diastolic, and mean AP were -14 (-36 to 9) and -12 (-37 to 13) for the nadir value and -7 (-29 to 15) and -2 (-28 to 25) for the peak value.
  
  
  CONCLUSIONS
  The CNAP monitor could detect acute change in AP within a reasonable time lag. Precision of its measurements is not satisfactory, and therefore, it could only serve as a clue to the occurrence of changes in AP.
authors.affiliation: Department of Anaesthesiology, Hôpital Foch, Suresnes, France; Department of Clinical Epidemiology and Biostatistics, INSERM U717, Université Paris 7 Diderot, Paris, France.
authors.forename: E
authors.initials: E
authors.lastname: Gayat
authors.forename: N
authors.initials: N
authors.lastname: Mongardon
authors.forename: O
authors.initials: O
authors.lastname: Tuil
authors.forename: K
authors.initials: K
authors.lastname: Sievert
authors.forename: T
authors.initials: T
authors.lastname: Chazot
authors.forename: N
authors.initials: N
authors.lastname: Liu
authors.forename: M
authors.initials: M
authors.lastname: Fischler
mesh_terms: D000368:Aged; D000768:Anesthesia, General; D062186:Arterial Pressure; D015924:Blood Pressure Monitors; D005260:Female; D006801:Humans; D007442:Intubation, Intratracheal; D008297:Male; D008875:Middle Aged