Noninvasive pulse pressure variation and stroke volume variation to predict fluid responsiveness at multiple thresholds: a prospective observational study.
BACKGROUND
Pulse pressure variation (PPV) and stroke volume variation (SVV) are dynamic preload variables that can be measured noninvasively to assess fluid responsiveness (FR) in anesthetized patients with mechanical ventilation. Few studies have examined the effectiveness of predicting FR according to the definition of FR, and assessment of inconclusive values of PPV and SVV around the cut-off value (the "grey zone") might improve individual FR prediction. We explored the ability of noninvasive volume clamp derived measurements of PPV and SVV to predict FR using the grey zone approach, and we assessed the influence of multiple thresholds on the predictive ability of the numerical definition of FR.


METHODS
Ninety patients undergoing general surgery were included in this prospective observational study and received a 500 mL fluid bolus as deemed clinically required by the attending anesthesiologist. A minimal relative increase in stroke volume index (↑SVI) was used to define FR with different thresholds from 10-25%. The PPV, SVV, and SVI were measured using the Nexfin® device that employs noninvasive volume clamp plethysmography.


RESULTS
The area under the receiver operator characteristic curve gradually increased for PPV / SVV with higher threshold values (from 0.818 / 0.760 at 10% ↑SVI to 0.928 / 0.944 at 25% ↑SVI). The grey zone limits of both PPV and SVV changed from 9-16% (PPV) and 5-13% (SVV) at the 10% ↑SVI threshold to 18-21% (PPV) and 14-16% (SVV) at the 25% ↑SVI threshold.


CONCLUSIONS
Noninvasive PPV and SVV measurements allow an acceptable FR prediction, although the reliability of both variables is dependent on the intended increase in SVI, which improves substantially with concomitant smaller grey zones at higher ↑SVI thresholds.
Department of Anesthesiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, PO BOX 30 001, 9700 RB, Groningen, The Netherlands. j.j.vos@umcg.nl.
Jaap Jan
JJ
Vos
Department of Anesthesiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, PO BOX 30 001, 9700 RB, Groningen, The Netherlands.
Marieke
M
Poterman
Department of Anesthesiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, PO BOX 30 001, 9700 RB, Groningen, The Netherlands.
Pieternel Papineau
PP
Salm
Department of Anesthesiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, PO BOX 30 001, 9700 RB, Groningen, The Netherlands.
Kai
K
Van Amsterdam
Department of Anesthesiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, PO BOX 30 001, 9700 RB, Groningen, The Netherlands.
Michel M R F
MM
Struys
Department of Anesthesiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, PO BOX 30 001, 9700 RB, Groningen, The Netherlands.
Thomas W L
TW
Scheeren
Department of Anesthesiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, PO BOX 30 001, 9700 RB, Groningen, The Netherlands.|Department of Anesthesiology and Intensive Care Medicine, Maria Middelares Hospital, Ghent, Belgium.
Alain F
AF
Kalmar
D000768:Anesthesia, General; D001794:Blood Pressure / Q000502:physiology*; D005260:Female; D005440:Fluid Therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012372:ROC Curve; D015203:Reproducibility of Results; D012121:Respiration, Artificial; D013318:Stroke Volume / Q000502:physiology*; D013514:Surgical Procedures, Operative