Continuous pulse oximetry in the general surgical ward: Nellcor N-200 versus Nellcor N-3000

New measurement principles in pulse oximetry have been introduced to decrea se the incidence of false movement alarms. Experimental studies have shown that the new Nellcor Symphony N-3000 may reduce the incidence of false alar ms when monitoring during different activities. We compared the Nellcor Sym phony N-3000 with the Nellcor N-200 pulse oximeter, when monitoring patient s in the general surgical ward. Twenty-two patients were monitored during u nrestricted ward activities for a total of 275 h with a N-3000 and a N-200 pulse oximeter simultaneously. Data were analysed for lack of concordance b etween the two pulse oximeters with respect to frequency of registered hypo xaemic episodes and thus the amount of time spent in the alarm state. The m edian number of desaturation episodes with the N-200 was 18 (range 0-511) c ompared with four (range 0-476) with the N-3000 (p < 0.0001). The median nu mber of drop-outs (loss of signal) was 13 (range 1-46) with the N-200 compa red with nine (2-41) with the N-3000 (p = 0.06). The N-200 registered satur ation values of 85% or below for 23% of the observation time compared with 6% of the observation time with the N-3000 pulse oximeter (p < 0.0001). The different working principles of the two generations of oximeters were refl ected in the present results derived from a clinical setting. The Nellcor S ymphony N-3000 may offer an advantage compared with the Nellcor N-200. beca use of the reduced frequency of alarms and total time in alarm when monitor ing patients in the general surgical ward.