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Performance Evaluation of Two Respiratory Inductance Plethysmography Performance Evaluation of Two Respiratory Inductance Plethysmography (RIP) Devices for Measurement of Respiratory Effort During Sleep.(RIP) Devices for Measurement of Respiratory Effort During Sleep.

A.M Rossely, E. San Pedro, T.J Churchward, P.D RochfordA.M Rossely, E. San Pedro, T.J Churchward, P.D RochfordInstitute for Breathing and Sleep, Heidelberg, AustraliaInstitute for Breathing and Sleep, Heidelberg, Australia

Department of Respiratory and Sleep Medicine, Austin Hospital, Heidelberg, AustraliaDepartment of Respiratory and Sleep Medicine, Austin Hospital, Heidelberg, Australia

AimsAimsThe aim of this study was to compare the measurement performance of the Compumedics (Melbourne, Australia) and Protech (U.S.A) RIP devices during PSG with respect to-1. Signal reliability.2. Whether BMI impacts on measurement performance

MethodMethod • Twenty one patients referred for routine clinical PSG wore both the Protech and the Compumedics RIP bands throughout their overnight sleep studies.

• Thoracic and abdominal bands were applied according to the manufacturers instructions. The Protech and Compumedics bands were applied immediately adjacent to each other. We had previously established that this arrangement did not alter the performance of RIP bands due to the possibility of electrical interaction.

• Epochs of 10 minute duration were assigned to one of four categories of signal quality, as presented below in figures 1a-d.

• >50% of epoch was required for a categorisation

IntroductionIntroduction• Respiratory Inductance Plethysmography (RIP) is an accepted surrogate of breathing effort during overnight polysomnography1. • There are a number of RIP devices currently available, some with marked design differences such as whether the active inductive element in the band extends partially or completely around the circumference of the patient, the vertical height and coil pattern of the element. • We have anecdotally observed that RIP signals from different manufacturers appear to vary in their reliability and susceptibility to noise during PSG, and that unreliable signals are more common in the obese.•There is little published data evaluating current RIP devices.

ResultsResults

Conclusions• Overall, signal reliability was far more consistent for the Protech RIP device compared with the Compumedics RIP device.

• The Compumedics device was substantially less reliable in obese compared with normal weight patients.

• We speculate that the performance difference might be due to the partially circumferential design of the Compumedics device.

• An analysis of breath amplitude performance is underway.

Figure 1a. Optimal signals

Figure 1b. One or both bands noisy but interpretable

Figure 1c. One band noisy and not interpretable

Figure 1d. Both bands noisy and not interpretable

Figure 2. Clustered bar chart demonstrates the proportion of all epochs that wereassigned a particular signal quality category by device type. The Protech bands produced optimal signals across 99% of all epochs analysed, compared with only 60% for the Compumedics device.

Figure 3. A significant interaction between RIP device type and Body Mass Index (BMI)is presented (F (2,18) = 4.79, p <.05, partial n2 = .35). Separate one way ANOVA analyses revealed a significantly lower proportion of epochs with optimal signals for the Compumedics device between the normal/overweight BMI category and the obese and morbidly obese categories. In contrast, no significant differences were found for the Protech device.

References • Berry. R.B., Brooks, R., Gamaldo, C.E., et al (2012). The AASM manual for the scoring of sleep and associated events: Rules, terminology and technical specifications, version 2.0,. Darien, Illinois: American Academy of Sleep Medicine.