Using Respiratory Variations of Plethysmographic Waveforms to Track Changes in Intravascular Volume during Hemodialysis.

摘要

Whereas dynamic indices have been shown to accurately predict volume status in mechanically ventilated patients, we still lack a reliable noninvasive means of intravascular volume status assessment in spontaneously breathing patients. The present study was undertaken to determine the impact of incentive spirometry (IS) on plethysmographic (PPG) waveforms in spontaneously breathing end stage renal disease (ESRD) patients. Furthermore, the impact of ultrafiltration on plethysmographic waveform variability in spontaneously breathing patients with and without incentive spirometry was analyzed.;With IRB approval, data were collected and analyzed for 44 hemodialysis cases. PPG waveforms were recorded at 100 Hz with a data acquisition system (S5 Collect) with patients first spontaneously breathing (SB) and then performing IS breathing. The waveforms were analyzed (spectrum, 4K, Hamming, Amplitude density) using Chart software (ADInstruments). Data were presented as mean +/- SD. The results were compared using the 2-tailed t-test, and P < 0.05 was considered statistically significant.;There was significant increase in the PPG DC with the use of IS, p value = 0.0000002. The average PPG DC at baseline was 1.06 +/- 0.82 with SB while average PPG DC with IS was 3.54 +/- 1.58, with percent change of 234% increase from baseline. Similarly, at the end of dialysis, a comparison between SB and IS showed a 203% change in the PPG DC value (1.92+/-1.03 with SB versus 5.819+/-2.84 with IS, p=0.000023). Whereas IS was consistently associated with a significant increase in PPG DC at the end of dialysis, SB was not associated with a significant increase in PPG DC at the end of dialysis when the ultrafiltrate rate exceeded 1000cc/hr.;Dynamic noninvasive hemodynamic evaluation has been shown to be more accurate than conventional hemodynamic static pressures; among the noninvasive methods is the PPG. This study showed a significant increase in PPG DC amplitude density during IS, and a significant increase in PPG DC during IS at the end of dialysis as compared to the beginning. This suggests that IS can be used as a tool to track changes in PPG DC variability in spontaneously breathing ESRD patients undergoing dialysis.