Comparison between pulse oximetry and transthoracic impedance alarm traces during home monitoring

OBJECTIVE

To compare transthoracic impedance (TTI/ECG) and pulse oximetry alarm traces detected during home monitoring in infants at risk of apnoea, bradycardia and hypoxaemia.

STUDY DESIGN

A retrospective evaluation of the monitor downloads of 67 infants who had undergone either TTI/ECG or pulse oximetry home monitoring using a device which can detect both parameters.

METHODS

The patients were categorised as: apparent life-threatening events (n = 39), preterm infants (n = 21) and miscellaneous (n = 7). TTI/ECG and pulse oximetry alarm traces were scored as either true or false alarms. Classification criteria were based on visual analysis of the impedance and plethysmographic waveforms captured by the memory monitor every time alarm thresholds were violated.

RESULTS

5242 alarms occurred over 3452 days of monitoring: 4562 (87%) were false and 680 (13%) true. The mean duration of monitoring was 51 days (range 5-220 days). There were 2982 TTI/ECG false alarms (65% of the total) and 1580 pulse oximetry false alarms (35%) (p = 0.0042). Of the 680 true alarms, 507 (74%) were desaturations not attributable to central apnoea and 173 (26%) were true TTI/ECG alarms (p = 0.0013).

CONCLUSIONS

Comparison of pulse oximetry and TTI/ECG alarm traces shows that true events were mostly attributable to desaturations, while false alarms were mainly provoked by TTI/ECG. The total number of false alarms is lower than reported in other studies using TTI/ECG only, thus indicating that monitoring using both pulse oximetry and TTI/ECG is suitable for home use. When the combination of both techniques is not feasible or not required, we recommend the use of motion resistant pulse oximetry alone.

International Child Care Practices Study: infant sleeping environment

BACKGROUND

The International Child Care Practices Study (ICCPS) has collected descriptive data from 21 centres in 17 countries. In this report, data are presented on the infant sleeping environment with the main focus being sudden infant death syndrome (SIDS) risk factors (bedsharing and infant using a pillow) and protective factors (infant sharing a room with adult) that are not yet well established in the literature.

METHODS

Using a standardised protocol, parents of infants were surveyed at birth by interview and at 3 months of age mainly by postal questionnaire. Centres were grouped according to geographic location. Also indicated was the level of SIDS awareness in the community, i.e. whether any campaigns or messages to "reduce the risks of SIDS" were available at the time of the survey.

RESULTS

Birth interview data were available for 5488 individual families and 4656 (85%) returned questionnaires at 3 months. Rates of bedsharing varied considerably (2-88%) and it appeared to be more common in the samples with a lower awareness of SIDS, but not necessarily a high SIDS rate. Countries with higher rates of bedsharing appeared to have a greater proportion of infants bedsharing for a longer duration (>5 h). Rates of room sharing varied (58-100%) with some of the lowest rates noted in centres with a higher awareness of SIDS. Rates of pillow use ranged from 4% to 95%.

CONCLUSIONS

It is likely that methods of bedsharing differ cross-culturally, and although further details were sought on different bedsharing practices, it was not possible to build up a composite picture of "typical" bedsharing practices in these different communities. These data highlight interesting patterns in child care in these diverse populations. Although these results should not be used to imply that any particular child care practice either increases or decreases the risk of SIDS, these findings should help to inject caution into the process of developing SIDS prevention campaigns for non-Western cultures.