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Testing preload responsiveness by the tidal volume challenge assessed by the photoplethysmographic perfusion index.
- Source :
- Critical Care; 9/16/2024, Vol. 28 Issue 1, p1-9, 9p
- Publication Year :
- 2024
-
Abstract
- Background: To detect preload responsiveness in patients ventilated with a tidal volume (Vt) at 6 mL/kg of predicted body weight (PBW), the Vt-challenge consists in increasing Vt from 6 to 8 mL/kg PBW and measuring the increase in pulse pressure variation (PPV). However, this requires an arterial catheter. The perfusion index (PI), which reflects the amplitude of the photoplethysmographic signal, may reflect stroke volume and its respiratory variation (pleth variability index, PVI) may estimate PPV. We assessed whether Vt-challenge-induced changes in PI or PVI could be as reliable as changes in PPV for detecting preload responsiveness defined by a PLR-induced increase in cardiac index (CI) ≥ 10%. Methods: In critically ill patients ventilated with Vt = 6 mL/kg PBW and no spontaneous breathing, haemodynamic (PICCO<subscript>2</subscript> system) and photoplethysmographic (Masimo-SET technique, sensor placed on the finger or the forehead) data were recorded during a Vt-challenge and a PLR test. Results: Among 63 screened patients, 21 (33%) were excluded because of an unstable PI signal and/or atrial fibrillation and 42 were included. During the Vt-challenge in the 16 preload responders, CI decreased by 4.8 ± 2.8% (percent change), PPV increased by 4.4 ± 1.9% (absolute change), PI<subscript>finger</subscript> decreased by 14.5 ± 10.7% (percent change), PVI<subscript>finger</subscript> increased by 1.9 ± 2.6% (absolute change), PI<subscript>forehead</subscript> decreased by 18.7 ± 10.9 (percent change) and PVI<subscript>forehead</subscript> increased by 1.0 ± 2.5 (absolute change). All these changes were larger than in preload non-responders. The area under the ROC curve (AUROC) for detecting preload responsiveness was 0.97 ± 0.02 for the Vt-challenge-induced changes in CI (percent change), 0.95 ± 0.04 for the Vt-challenge-induced changes in PPV (absolute change), 0.98 ± 0.02 for Vt-challenge-induced changes in PI<subscript>forehead</subscript> (percent change) and 0.85 ± 0.05 for Vt-challenge-induced changes in PI<subscript>finger</subscript> (percent change) (p = 0.04 vs. PI<subscript>forehead</subscript>). The AUROC for the Vt-challenge-induced changes in PVI<subscript>forehead</subscript> and PVI<subscript>finger</subscript> was significantly larger than 0.50, but smaller than the AUROC for the Vt-challenge-induced changes in PPV. Conclusions: In patients under mechanical ventilation with no spontaneous breathing and/or atrial fibrillation, changes in PI detected during Vt-challenge reliably detected preload responsiveness. The reliability was better when PI was measured on the forehead than on the fingertip. Changes in PVI during the Vt-challenge also detected preload responsiveness, but with lower accuracy. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 13648535
- Volume :
- 28
- Issue :
- 1
- Database :
- Complementary Index
- Journal :
- Critical Care
- Publication Type :
- Academic Journal
- Accession number :
- 179669329
- Full Text :
- https://doi.org/10.1186/s13054-024-05085-w