Clinical evaluation of the on-line Sensicath blood gas monitoring system

Blood gas analysis is an integral part of the management of open heart surgery and post-surgical intensive care patients. This study was conducted to compare the results of on-line blood gas analysis using the new Sensicath (SC) optical sensor technology against standard blood gas assay.

Comparative blood gas analysis was performed on 45 postoperative cardiovascular surgical patients and 5 patients during cardiopulmonary bypass. Simultaneous samples were obtained. One sample was sent to the central hospital laboratory for measurement using a Radiometer ABL 500 blood gas analyzer and the second sample was drawn past the optical sensor. Comparisons between the two methods for pH, pO2 and pCO2 were analyzed using linear regression and the method of Bland and Altman for the intensive care unit samples (N = 451) while the T test was used to compare data points obtained during cardiopulmonary bypass (N = 57). Bias, accuracy and precision were also calculated.

The regression lines (r2) for pH, pO2, and pCO2 and were 0.69, 0.94, and 0.68 with slopes of 1.000, 0.0957, and 1.052 respectively for postoperative surgical patients. During cardiopulmonary bypass, the T test did not show any significant difference between the Sensicath and the reference values for the arterial and venous pH, pO2 and pCO2.

In summary, this study found the Sensicath to be an accurate, useful tool which permits immediate blood gas analysis without blood exposure and constitutes an advance in the field of intensive care monitoring.