Pulse oximetry in the air rescue service. 2: Methods of increasing the stability of pulse oximetry measurements--ECG-synchronized pulse oximetry and adhesive sensors

Abstract

Pulse oximetric monitoring in air rescue service (rescue helicopter) is primarily influenced by motion artifacts (especially those of a passive nature), by low perfusion and by the problem of probe dislocation. In a prospective study involving 162 unselected emergency patients treated by the medical team of the emergency helicopter service "Christoph 22" (Ulm), we studied the possibility of reducing these adverse factors by applying available state-of-the-art technology, such as ECG-synchronization and adhesive probes. By applying the thus modified methods of monitoring, the interference factor was reduced to S = 0.056, that is only 5.6% of measurement time was adversely effected. The increase in measurement stability resulted from the reduction in number of described artifacts (motion artifacts and low perfusion), as well as from the reduction in duration of interfered measurement time. ECG-synchronization very effectively influenced the passive motion artifacts. Their frequency was reduced by the factor 8.2, respectively 42. An effective reduction in number of probe dislocations can be achieved by applying adhesive probes. The high costs of such probes presently limits their application. Radiation can be eliminated by redesigning the probe. ECG-synchronization of pulse oximetric signal has proved to be a method to reduce the artifacts frequently experienced in air rescue and has considerably contributed to the increase of emergency patient safety.