Format

Send to

Choose Destination
See comment in PubMed Commons below
Chest. 2001 Aug;120(2):384-9.

Home oximetry studies for diagnosis of sleep apnea/hypopnea syndrome: limitation of memory storage capabilities.

Author information

1
Department of Respiratory Medicine, Bristol Royal Infirmary, Bristol, England.

Abstract

BACKGROUND:

Memory oximeters enable diagnostic studies for sleep apnea hypopnea syndrome (SAHS) to be performed in the home. However, memory capabilities may be limited.

STUDY OBJECTIVES:

To compare a pulse oximeter used at home with an 8-h memory, storing data every 12 s, and in the laboratory, with on-line recording every 2 s.

DESIGN:

Prospective cohort study.

SETTING:

Patients' homes and a sleep laboratory.

PATIENTS:

One hundred patients with suspected SAHS.

MEASUREMENTS:

Home oximetry and a laboratory full polysomnography. The number of >/= 4% dips in pulse oximetric saturation (SpO(2)) was calculated for each study. Daytime sleepiness was assessed by the Epworth Sleepiness Scale (ESS) score.

RESULTS:

The mean dips per hour were 5.3/h (range, 0 to 53/h) for home studies and 13.4/h (range, 0 to 106/h) for laboratory studies; the relationship between home and laboratory studies was as follows: home = (0.4 x laboratory) - 0.01 +/- 11.2; r(2) = 0.64. Mean difference was 8.4/h (- 2.5 to + 77.9/h), which correlated with the mean of the measurements. At a cutoff point of 10/h, 52 studies were both negative and 13 studies were both positive. Nineteen home studies were false-negatives. Sensitivity was 0.41, and specificity was 1.0. In these 19 studies, 7 patients had an ESS score > 10 and 4 patients had an ESS score > 14. To confirm that differences were due to different sampling rates, 16 additional patients had on-line data and stored data collected simultaneously in the laboratory. Mean dips per hour were 3.2/h (range, 0.1 to 18.3/h) for the stored data and 8.34/h (0.2 to 22.8/h) for on-line data; the relationship being stored was as follows: 0.5 on-line - 1.17 +/- 2.6; r(2) = 0.69. Mean difference was 5.2/h (0.04 to 15.4 h), which correlated with the mean of the measurements.

CONCLUSION:

Home studies using a memory storage pulse oximeter may underestimate the number of hypoxic dips, probably due to sampling rates. Clinically significant hypoxic SAHS may therefore be missed.

PMID:
11502633
[Indexed for MEDLINE]
PubMed Commons home

PubMed Commons

0 comments

    Supplemental Content

    Full text links

    Icon for Elsevier Science
    Loading ...
    Support Center