Evaluation of respiratory inductive plethysmography: accuracy for analysis of respiratory waveforms.
OBJECTIVE
To assess the accuracy of respiratory inductive plethysmography (RIP) waveforms to those obtained with whole body plethysmograph (BP) as this device gives a plethysmographic signal and a pneumotachograph (PNT).


METHODS
Randomized controlled trial.


METHODS
Physiologic laboratory in a university hospital.


METHODS
Eleven subjects from the laboratory staff.


METHODS
This study was achieved during four consecutive periods in subjects breathing spontaneously and through different added resistive loads. Using the least square method calibration, two RIP waveforms, VRIP.BP(t) and VRIP.PNT(t), were simultaneously calculated with coefficients obtained from BP and from PNT volume waveforms, respectively VBP(t) and VPNT(t). For each recording, to compare volume waveforms, we calculated their differences in term of distances, DRIP-BP and DRIP-PNT, between the normalized RIP volume signal (respectively, VRIP.BP[t] and VRIP.PNT[t]) and its normalized reference (respectively, VBP[t] and VPNT[t]). We also calculated the distance DPNT-BP between the two normalized references VBP(t) and VPNT(t).


RESULTS
No significant effect of load or time on the distance occurred. Including all the recordings, the mean distance DRIP-BP (3.4+/-1.1%) appears significantly lower than both the mean distance DRIP-PNT (4.5+/-1.3%; p<0.04) and the mean distance DPNT-BP (4.6+/-0.9%; p<0.008). For each period or load level, DRIP-BP appears to be lower than DRIP-PNT and DPNT-BP.


CONCLUSIONS
The RIP seems reasonably accurate for analysis of respiratory waveform while subjects subsequently breathe against resistive loads.
Carry
P Y
PY
Faculté de Médecine de Grenoble, PRETA-TIMC/IMAG, La Tronche, France.
Baconnier
P
P
Eberhard
A
A
Cotte
P
P
Benchetrit
G
G
D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010991:Plethysmography / Q000379:methods / Q000592:standards*; D010993:Plethysmography, Whole Body; D012119:Respiration / Q000502:physiology*; D012129:Respiratory Function Tests / Q000592:standards