Comparison of Changes in PPV Using a Tidal Volume Challenge with a Passive Leg Raising Test to Predict Fluid Responsiveness in Patients Ventilated Using Low Tidal Volume

Abstract

A bstract Background Tidal volume challenge pulse pressure variation (TVC-PPV) is considered one of the recent reliable dynamic indices of fluid responsiveness (FR); also, passive leg raising (PLR)-induced changes in cardiac output (CO) detected by echocardiography are considered a reliable reversible self-fluid challenge test; many patients share eligibility for both tests. Objectives The study aimed to compare the sensitivity and specificity of both tests for the prediction of FR in mechanically ventilated patients with hemodynamic instability. Methods We studied 46 patients. Hemodynamic parameters including PPV and CO (detected by velocity time integral (VTI) using echocardiography) recorded at tidal volume (VT) of 6 mL/kg/ideal body weight (IBW) in semi-recumbent position then recorded again after one-minute increase in TV from 6 to 8 mL/kg/IBW then recorded with PLR at TV of 6 mL/kg/IBW and finally with actual volume expansion in semi-recumbent position by 4 ml/kg bolus of crystalloid solution to define actual responders with increase of cardiac output of 15% or more. Results Sixteen patients were responders, and thirty patients were nonresponders; responders had significant increase in PPV with TVC 6 to 8 ml/kg/IBW with best cutoff value of 3.5 with a sensitivity of 93.8% and a specificity of 93.9%. PLR test-induced changes in CO had a sensitivity of 93.9% and a specificity of 86.7% with statistically best cutoff value of 6.5% increase in CO, but sensitivity was 75% at cutoff value of 10% increase in CO. Other parameters like PPV, PPV changes with PLR test, and PPV changes with fluid expansion were less sensitive indicators. Conclusion FR in patients with hemodynamic instability and mechanically ventilated with low tidal volume strategy can be efficiently predicted when PPV increases more than 3.5 with tidal volume challenge and when PLR induces 6.5% increase in CO monitored through VTI method by Doppler echocardiography, and both tests are equally reliable. How to cite this article Elsayed AI, Selim KAW, Zaghla HE, Mowafy HE, Fakher MA. Comparison of Changes in PPV Using a Tidal Volume Challenge with a Passive Leg Raising Test to Predict Fluid Responsiveness in Patients Ventilated Using Low Tidal Volume. Indian J Crit Care Med 2021;25(6):685–690.

Does tidal volume challenge improve the feasibility of pulse pressure variation in patients mechanically ventilated at low tidal volumes? A systematic review and meta-analysis

“…The black diamond squares represent percentage change of pulse pressure variation (△PPV%). The cutoff values of △PPV are as follows: (1) Myatra 2017 [ 14 ], 3.5%; (2) Jun 2019 [ 16 ], 1%; (3) Elsayed 2021 [ 19 ], 3.5%; (4) Taccheri 2021 [ 20 ], 1%; Hamzaoui2021 [ 21 ]; (5) Shi 2022 [ 22 ], 3.5%; (6) Xu 2022 [ 23 ], 2%. The cutoff values of △PPV% are as follows: (1) Myatra 2017 [ 14 ], 48%; (2)Yonis 2017 [ 15 ], 29%; (3) Jun 2019 [ 16 ], 25%; (4) Messina 2019 [ 17 ], 13.3%; (5) Messina 2020 [ 18 ], 12%; (6) Taccheri 2021 [ 20 ], 20%; …”

Prediction of fluid responsiveness. What’s new?

“…The Vt challenge has been validated by far fewer studies than the PLR test, for example, although its reliability has been confirmed in a recent meta-analysis [ 54 ]. Moreover, the diagnostic thresholds differ slightly between the few available studies (Table 2 ), which in addition expressed the change in PPV either as an absolute value [ 30 , 52 , 65 ]} or as a percent change [ 56 , 66 , 67 ], or both [ 29 ].…”