ARTERIAL PULSE PRESSURE VARIATION PREDICTING FLUID RESPONSIVENESS IN CRITICALLY ILL PATIENTS: Retracted

Perioperative Fluid Therapy

Anesthesia can lead to pathophysiologic changes that dramatically alter the fluid balance of the body compartments and the intravascular space. Fluid administration can be monitored and evaluated using static and dynamic indexes. Guidelines for fluid rates during anesthesia begin with 3 mL/kg/h in cats and 5 mL/kg/h in dogs. If at all possible, patients should be stabilized and electrolyte disturbances should be corrected before general anesthesia.

Does stroke volume variation predict fluid responsiveness in children: A systematic review and meta-analysis

OBJECTIVE

Stroke volume variation (SVV) is a reliable predictor of fluid responsiveness in adult patients. However, the predictive value of SVV is uncertain in pediatric patients. We performed the first systematic meta-analysis to evaluate the diagnostic value of SVV in predicting fluid responsiveness in children.

METHODS

PUBMED, EMBASE, and Cochrane Central Register of Controlled Trials were searched up to December 2016. Original studies assessing the diagnostic accuracy of SVV in predicting fluid responsiveness in children were considered to be eligible. A random-effects model was used to calculate pooled values of sensitivity, specificity and diagnostic odds ratio with 95% CI. The summary receiver operating characteristic curve was estimated and area under the curve was calculated. Quality of the studies was assessed with the QUADAS-2 tool.

RESULTS

Six studies with a total of 279 fluid boluses in 224 children were included. The analysis demonstrated a pooled sensitivity of 0.68 (95% CI,0.59-0.76), pooled specificity of 0.65 (95% CI, 0.57-0.73), pooled diagnostic odds ratio of 8.24 (95% CI, 2.58-26.30), and the summary area under the summary receiver operating characteristic curve of 0.81. However, significant inter-study heterogeneity was found (p<0.05, I2 = 61.3%), likely due to small sample size and diverse study characteristics.

CONCLUSIONS

Current evidence suggests that SVV was of diagnostic value in predicting fluid responsiveness in children under mechanical ventilation. Given the high heterogeneity of published data, further studies are needed to confirm the diagnostic accuracy of SVV in predicting fluid responsiveness in pediatric patients.

Pulse pressure variation as a guide for volume expansion in dogs undergoing orthopedic surgery

OBJECTIVE

To investigate whether pulse pressure variation (PPV) can predict fluid responsiveness in healthy dogs during clinical surgery.

STUDY DESIGN

Prospective clinical study.

ANIMALS

Thirty-three isoflurane-anesthetized dogs with arterial hypotension during orthopedic surgery.

METHODS

Fluid challenge with lactated Ringer's solution (15 mL kg^-1 in 15 minutes) was administered in mechanically ventilated dogs (tidal volume 10 mL kg^-1) with hypotension [mean arterial pressure (MAP) < 65 mmHg]. The volume expansion was considered effective if cardiac output (CO; transesophageal Doppler) increased by ≥ 15%. Cardiopulmonary data were analyzed using two-way ANOVA, receiver operating characteristics (ROC) curves and Spearman coefficient; p < 0.05 was considered significant.

RESULTS

Effective volume expansion, mean ± standard deviation 42 ± 4% increase in CO (p < 0.0001) was observed in 76% of the dogs, resulting in a decrease in PPV (p < 0.0001) and increase in MAP (p < 0.0001), central venous pressure (CVP; p = 0.02) and ejection fraction (p < 0.0001) compared with before the fluid challenge. None of these changes occurred when volume expansion resulted in a nonsignificant CO increase of 4 ± 5%. No significant differences were observed in blood gas analysis between responsive and nonresponsive dogs. The increase in CO was correlated with the decrease in PPV (r = -0.65; p < 0.0001) but absolute values of CO and PPV were not correlated. The PPV performance (ROC curve area: 0.89 ± 0.06, p = 0.0011) was better than that of CVP (ROC curve area: 0.54 ± 0.12) and MAP (ROC curve area: 0.59 ± 0.13) to predict fluid responsiveness. The best cut-off for PPV to distinguish responders and nonresponders was 15% (50% sensitivity and 96% specificity).

CONCLUSIONS AND CLINICAL RELEVANCE

In mechanically ventilated, healthy, isoflurane-anesthetized dogs, PPV predicted fluid responsiveness to volume expansion, and MAP and CVP did not show such applicability.

Right internal jugular vein distensibility appears to be a surrogate marker for inferior vena cava vein distensibility for evaluating fluid responsiveness

Objective

To investigate whether the respiratory variation of the inferior vena cava diameter (∆DIVC) and right internal jugular vein diameter (∆DRIJ) are correlated in mechanically ventilated patients.

Methods

This study was a prospective clinical analysis in an intensive care unit at a university hospital. Thirty-nine mechanically ventilated patients with hemodynamic instability were included. ∆DIVC and ∆DRIJ were assessed by echography. Vein distensibility was calculated as the ratio of (A) Dmax - Dmin/Dmin and (B) Dmax - Dmin/ mean of Dmax - Dmin and expressed as a percentage.

Results

∆DIVC and ∆DRIJ were correlated by both methods: (A) r = 0.34, p = 0.04 and (B) r = 0.51, p = 0.001. Using 18% for ∆DIVC, indicating fluid responsiveness by method (A), 16 patients were responders and 35 measurements showed agreement (weighted Kappa = 0.80). The area under the ROC curve was 0.951 (95%CI 0.830 - 0.993; cutoff = 18.92). Using 12% for ∆DIVC, indicating fluid responsiveness by method (B), 14 patients were responders and 32 measurements showed agreement (weighted Kappa = 0.65). The area under the ROC curve was 0.903 (95%CI 0.765 - 0.973; cut-off value = 11.86).

Conclusion

The respiratory variation of the inferior vena cava and the right internal jugular veins are correlated and showed significant agreement. Evaluation of right internal jugular vein distensibility appears to be a surrogate marker for inferior vena cava vein distensibility for evaluating fluid responsiveness.

Changes in pulse pressure following fluid loading: a comparison between aortic root (non-invasive tonometry) and femoral artery (invasive recordings)

PURPOSE

To document the relationship between stroke volume (SV) and pulse pressure (PP) recorded at the femoral and aortic sites during volume expansion (VE) in patients in shock. We hypothesized that non-invasively estimated aortic PP would exhibit the same ability as PP recorded invasively at the femoral level to track SV changes.

METHODS

Included in this prospective study were 56 ICU patients needing VE. Femoral PP (indwelling catheter), aortic PP (tonometry) and cardiac output (thermodilution) were recorded before and after VE. Responders were defined as patients who showed an increase in SV of ≥15% after VE.

RESULTS

Of the 56 included patients in shock, 39 (age 57 ± 14 years, SAPS II 46 ± 18) completed the study. At both sites, PP increased after VE in responders (n=17, mean SV increase 30 ± 15%) but not in non-responders. In the overall population, there was a positive relationship between VE-induced changes in SV and in PP at the femoral (r=0.60, p<0.001) and aortic (r=0.52, p<0.001) sites. Increases in femoral PP of ≥9% indicated SV increases of ≥15% with 82% sensitivity and 95% specificity. Increases in aortic PP of ≥4.5% indicated SV increases of ≥15% with 76% sensitivity and 82% specificity. Areas under the ROC curves indicated that aortic PP was not different from femoral PP for tracking changes in SV.

CONCLUSION

The ability of non-invasively estimated aortic PP to track fluid response was the same as that of invasively recorded femoral PP. This may have implications for non-invasive haemodynamic monitoring.

Pleth variability index predicts fluid responsiveness in critically ill patients

OBJECTIVE

To investigate whether the pleth variability index, a noninvasive and continuous tool, can predict fluid responsiveness in mechanically ventilated patients with circulatory insufficiency.

DESIGN

Prospective study.

SETTING

Surgical intensive care unit of a university hospital.

PATIENTS

Forty mechanically ventilated patients with circulatory insufficiency in whom volume expansion was planned by attending physician. Exclusion criteria included spontaneous respiratory activity, cardiac arrhythmia, known intracardiac shunt, severe hypoxemia (Pao2/Fio2 <100 mm Hg), contraindication for passive leg raising, left ventricular ejection fraction of <50%, and hemodynamic instability during the procedure.

INTERVENTIONS

Fluid challenge with 500 mL of 130/0.4 hydroxyethyl-starch if respiratory variations in arterial pulse pressure were ≥ 13% or with passive leg raising if variations in arterial pulse pressure were <13%.

MEASUREMENTS AND MAIN RESULTS

Pleth variability index, variations in arterial pulse pressure, and cardiac output estimated by echocardiography were recorded before and after fluid challenge. Fluid responsiveness was defined as an increase in cardiac output of ≥ 15%. Twenty-one patients were responders and 19 were nonresponders. Mean ± sd pleth variability index (28% ± 13% vs. 11% ± 4%) and arterial pulse pressure variation (22% ± 11% vs. 5% ± 2%) values at baseline were significantly higher in responders than in nonresponders. The pleth variability index threshold value of 17% allowed discrimination between responders and nonresponders with a sensitivity of 95% (95% confidence interval, 74% to 100%) and a specificity of 91% (95% confidence interval, 70% to 99%). The pleth variability index at baseline correlated (r = .72, p < .0001) with the percentage change in cardiac output induced by fluid challenge, suggesting that a higher pleth variability index at baseline will correlate with a higher percentage change in cardiac output after volume expansion.

CONCLUSIONS

The pleth variability index can predict fluid responsiveness noninvasively in intensive care unit patients under mechanical ventilation.