Fluid responsiveness in critically ill patients

Effect of VTILVOT variation rate on the assessment of fluid responsiveness in septic shock patients

This study aimed to assess the predictive value of velocity time integral (VTI) of the left ventricular outflow tract (LVOT) on volume expansion test (VET) as an indicator of volume responsiveness in septic shock patients. Septic shock patients undergoing mechanical ventilation were recruited. The hemodynamic parameters before and after VE were monitored by pulse indicated continuous cardiac output (PiCCO) and echocardiography. Heart rate, cardiac index (CI), mean arterial pressure (MAP), central venous pressure, stroke volume variation (SVV), CI and variation of pulse pressure (PPV), and the changes in cardiac parameters (Dheart rate, Dmean arterial pressure, Dcentral venous pressure, DSVV, DCI, and DPPV) were determined. The relationships of hemodynamic parameters and their changes with DVTI were further evaluated with Pearson relation analysis. The value of these parameters in fluid responsiveness prediction was evaluated by using the receiver operating characteristic (ROC) curve analysis. Results showed that 44 VETs were performed in 44 septic shock patients with responsiveness in 24 patients and non-responsiveness in 20. The CI increased by ≥ 15% in responsive patients, but by<15% in non-responsive patients after VET. There were significant differences in the SVV and PPV after VET between responsive and non-responsive groups. DSVV, DPPV, and DCI were positively related to DVTI. The area under ROC curve (AUC) for SVV in fluid responsiveness prediction was 0.80, and the sensitivity and specificity of SVV were 66.5% and 95%, respectively, when the cut-off value was 24.8%. The AUC for PPV in fluid responsiveness prediction was 0.843, and the sensitivity and specificity of PPV were 83.3% and 75%, respectively, when the cut-off value was 25.8%. The AUC for DVTILVOT in fluid responsiveness prediction was 0.956, and the sensitivity and specificity were 87.5% and 95%, respectively, when the cut-off value was 15.9%. In conclusion, DVTILVOT is effective to predict fluid responsiveness after VET in mechanical ventilation patients with septic shock. It may serve as a new, noninvasive and functional hemodynamic parameter with the same accuracy to SVV.

Dynamic Tests to Predict Fluid Responsiveness After Off-Pump Coronary Artery Bypass Grafting

OBJECTIVE

To test the hypothesis that a positive end-expiratory pressure test and the mini-fluid challenge predict fluid responsiveness in patients after off-pump coronary artery bypass grafting.

DESIGN

Single-center pilot prospective observational study.

SETTING

City Hospital #1 of Arkhangelsk, Russian Federation.

PARTICIPANTS

Thirty-two adult patients after off-pump coronary artery surgery.

INTERVENTIONS

To assess fluid responsiveness, after arrival to the intensive care unit, all patients received a test with increase in positive end-expiratory pressure from 5 to 20 cmH₂O for 2 minutes, a mini-fluid challenge test with administration of crystalloids at 1.5 mL/kg during 2 minutes, and standard fluid challenge test using 7 mL/kg during 10 minutes.

MEASUREMENTS AND MAIN RESULTS

The patients with an increase in cardiac index by ≥15% after a standard fluid challenge test were defined as fluid responders. According to receiver operating characteristic analysis, a decrease in mean arterial pressure exceeding 5 mmHg in 120 seconds of the positive end-expiratory pressure test identified fluid responsiveness with an area under the curve of 0.73 (p = 0.03). The reduction in pulse pressure and stroke volume variations by more than 2% during mini-fluid challenge test predicted positive response to fluid load with an area under the curve of 0.77 and 0.75, respectively (p < 0.05).

CONCLUSION

Both the positive end-expiratory pressure test and the mini-fluid challenge test are feasible after off-pump coronary artery bypass grafting and can be used to predict fluid responsiveness in these patients.

Internal jugular vein variability predicts fluid responsiveness in cardiac surgical patients with mechanical ventilation

BACKGROUND

To evaluate the efficacy of using internal jugular vein variability (IJVV) as an index of fluid responsiveness in mechanically ventilated patients after cardiac surgery.

METHODS

Seventy patients were assessed after cardiac surgery. Hemodynamic data coupled with ultrasound evaluation of IJVV and inferior vena cava variability (IVCV) were collected and calculated at baseline, after a passive leg raising (PLR) test and after a 500-ml fluid challenge. Patients were divided into volume responders (increase in stroke volume ≥ 15%) and non-responders (increase in stroke volume < 15%). We compared the differences in measured variables between responders and non-responders and tested the ability of the indices to predict fluid responsiveness.

RESULTS

Thirty-five (50%) patients were fluid responders. Responders presented higher IJVV, IVCV and stroke volume variation (SVV) compared with non-responders at baseline (P < 0.05). The relationship between IJVV and SVV was moderately correlated (r = 0.51, P < 0.01). The areas under the receiver operating characteristic (ROC) curves for predicting fluid responsiveness were 0.88 (CI 0.78-0.94) for IJVV compared with 0.83 (CI 0.72-0.91), 0.97 (CI 0.89-0.99), 0.91 (CI 0.82-0.97) for IVCV, SVV, and the increase in stroke volume in response to a PLR test, respectively.

CONCLUSIONS

Ultrasound-derived IJVV is an accurate, easily acquired noninvasive parameter of fluid responsiveness in mechanically ventilated postoperative cardiac surgery patients, with a performance similar to that of IVCV.