Calibration of respiratory inductive plethysmograph during natural breathing

摘要: We describe a single-posture method for deriving the proportionality constant (K) between rib cage (RC) and abdominal (AB) amplifiers of respiratory inductive plethysmograph (RIP). Qualitative diagnostic calibration (QDC) is based on equations isovolume maneuver (ISOCAL) carried out during 5-min period natural breathing without using mouthpiece or mask. In this situation, K approximates ratio standard deviations (SD) uncalibrated changes AB-to-RC volume deflections. Validity was evaluated by 1) analyzing RIP waveforms an 2) comparing tidal (VT) amplitude functional residual capacity (FRC) level measured spirometry (SP) with values. Comparisons VT(RIP) to VT(SP) were also obtained in variety postures (uninstructed) preferential RC AB voluntary VT FRC level. VT(RIP)-to-VT(SP) comparisons equal closer than published reports single posture, ISOCAL, multiple- linear-regression procedures. QDC supine posture SP that others showed better accuracy horizontal upright postures.