Toward better home respiratory monitoring: a comparison of impedance and inductance pneumography.

Various respiratory monitoring methods have been used as a part of home respiratory care, but none has been accepted as a universal method. Impedance pneumography is the most popular method at present and is used in the form of cardiorespiratory monitoring, but it has limitations for diagnosing obstructive airway problems and a high incidence of false alarms. We evaluated a new investigational method, inductance pneumography, in terms of the incidence of false alarms (waveform out of range), using infants recovering from general anesthesia. They were used for this study because they go through all the stages of sleep in a short period and their relatively long period of light sleep was advantageous in evaluating motion artifact interference. Waveforms went out of range 24.6 +/- 2.9% of the time with impedance pneumography and 15.9 +/- 4.5% with pulse oximeter, but 11.0 +/- 3.4% with inductance pneumography. These differences are statistically significant (P < 0.01). Electrocardiography electrodes for impedance pneumography dislodged briefly in one case but the Respiband dislodged in four cases and the Flex II probe dislodged in three cases, indicating the need for better fixation of sensors. It was found that inductance pneumography, in addition to being able to detect obstructive apnea, has a significantly lower incidence of false alarms. Further elaboration of this method is warranted for better home respiratory monitoring.