Dynamic Maneuvers and Their Diagnostic Value
Vt Challenge:
A transient increase in Vt from 6 mL/kg to 8 mL/kg for one minute, with a PPV increase ≥3.5%, suggests preload responsiveness.
Benefits include simplicity and minimal equipment requirements.
Threshold variability and false positives in ACP remain concerns.
End-Expiratory Occlusion Test:
A 15-second interruption of ventilation at end-expiration increases preload, and a rise in cardiac output ≥5% confirms preload responsiveness.
Requires precise cardiac output measurement and patient tolerance for respiratory pauses.
PEEP Test:
Lowering positive end-expiratory pressure (PEEP) from ≥10 cmH2O to 5 cmH2O with a CO increase ≥9% predicts preload responsiveness.
Risk of lung de-recruitment is a potential limitation.
Using the ventilator to predict fluid responsiveness | Intensive Care Medicine