Shin WJ, Choi JM, Kong YG, Song JG, Kim YK, Hwang GS. Spectral analysis of respiratory-related hemodynamic variables in simulated hypovolemia: a study in healthy volunteers with spontaneous breathing using a paced breathing activity.
Korean J Anesthesiol 2010;
58:542-9. [PMID:
20589179 PMCID:
PMC2892588 DOI:
10.4097/kjae.2010.58.6.542]
[Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Revised: 03/10/2010] [Accepted: 03/29/2010] [Indexed: 11/23/2022] Open
Abstract
Background
A dynamic preload index such as stroke volume variation (SVV) is not as reliable in spontaneous breathing (SB) patients as in mechanically ventilated patients. This study examined the hypothesis that spectral analysis of hemodynamic variables during paced breathing (PB) activity may be a feasible index of volume changes and fluid responsiveness, despite insufficient respiratory changes in the preload index during SB activity.
Methods
Blood pressure and stroke volume (SV) were measured in 16 subjects undergoing PB (15 breaths/min), using a Finometer device and the Modelflow method. Respiratory systolic pressure variation (SPV) and SVV were measured and respiratory frequency (RF, 0.2-0.3 Hz) of power spectra of SPV (SPVRF) and SVV (SVVRF) were computed using fast Fourier transformation. Progressive hypovolemia was simulated with lower body negative pressure (LBNP). Volume challenges were produced by infusion of normal saline and subsequent release of LBNP to baseline. Fluid responsiveness, defined as a >20% increase in SV, was assessed by the area under the curve (AUC) of receiver operating characteristic curves.
Results
Graded hypovolemia caused a significant increase in SPVRF and a decrease in SVVRF. During volume expansion, SPVRF decreased and SVVRF rose significantly. Fluid responsiveness was better predicted with SVVRF (AUC 0.75) than with SPVRF, SPV, or SVV. SVVRF before volume challenge was significantly correlated with volume expansion-induced changes in SV (r = -0.64).
Conclusions
These results suggest that RF spectral analysis of dynamic preload variables may enable the detection of volume change and fluid responsiveness in SB hypovolemic patients performing PB activity.
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