Líffræðifélag Íslands
Líffræðiráðstefnan 2015

Erindi/veggspjald / Talk/poster V40

Validation of a novel non-invasive method to assess respiratory effort

Serwatko M1,2., Agustsson J.S3., Torfason R1., Hoskuldsson S3., Karlsson Karl Æ2., Gislason, T1., Arnardottir E.S1.

1. Department of Respiratory Medicine and Sleep, Landspitali – The National University Hospital of Iceland, Reykjavik, Iceland 2. Reykjavik University, School of Science and Engineering, Reykjavik, Iceland 3. Nox Medical, Reykjavik, Iceland

Kynnir / Presenter: Serwatko, M.

Tengiliður / Corresponding author: Karlsson, K.Æ. (karlsson@ru.is)

The aim of the study is to assess a novel method of obtaining information on sleep respiratory effort using calibrated respiratory inductance plethysmography (cRIP) belts that thus far has required the highly invasive esophageal pressure (Pes) measurement. Thirty subjects were studied, undergoing nocturnal home polysomnography with simultaneous Pes measurement. Pes events were manually scored and defined as an abrupt change in the peak to peak (PP) value, when a crescendo pattern for >10 sec, from baseline (-10cmH2O), was present. Events in cRIP were found by calculating the respiratory power loss (PL). The PL is the power lost to paradoxical movements in the thorax and abdomen while an obstruction occurs. The PL can be quantified by comparing the power in the thorax and abdomen movements, to the power of the total respiratory movement, sum of the thorax and abdomen. The PL events were analyzed when Pes events were scored. Indices describing, separately, the Pes events and the PL events, based on the ratio of a scored event (i.e. pes event, apnea/hypopnea) and non-event (i.e. normal breathing), were assigned to each method, and the indices were subsequently compared. On average, the relative drop in the Pes index = 1.13 ± 0.25 and for PL index = 1.40 ± 0.45 during Pes events. Comparing the drop in Pes index during apneas/hypopneas the mean relative drop was 1.86 ± 0.65 and for PL index = 2.40 ± 0.69. The PL signal acts similarly to the Pes signal, with build-up and sharp changes at respiratory events. Peak to peak values for Pes and PL increase during respiratory events compared to normal breathing. Respiratory effort calculated from cRIP is a new, promising method but needs further validation, e.g. during REM periods with its concurrent loss in muscle tone.