Aims:The aim of this study was to investigate whether respiratory variations in carotid and aortic blood flows measured by Doppler ultrasonography could accurately predict fluid responsiveness in critically ill children.
Methods:This was a prospective single-center study including mechanically ventilated children who underwent fluid replacement at the discretion of the attending physician. Response to fluid load was defined by a stroke volume increase of more than 15%. Maximum and minimum values of velocity peaks were determined over one controlled respiratory cycle before and after volume expansion. Respiratory changes in velocity peak of the carotid (∆Vpeak_Ca) and aortic (∆Vpeak_Ao) blood flows were calculated as the difference between the maximum and minimum values divided by the mean of the two values and were expressed as a percentage.Results: A total of 30 patients were included, of which twelve (40%) were fluid responders and 18 (60%) non-responders. Before volume expansion, both ∆Vpeak_Ca and ∆Vpeak_Ao were higher in responders than in non-responders (17.1% vs 4.4%; p < .001 and 22.8% vs 6.4%; p < .001, respectively). ∆Vpeak_Ca could effectively predict fluid responsiveness (AUC 1.00, 95% CI 0.88-1.00), as well as ∆Vpeak_Ao (AUC 0.94, 95% CI 0.80-0.99). The best cutoff values were 10.6% for ∆Vpeak_Ca (sensitivity, specificity, positive predictive value and negative predictive value of 100%) and 18.2% for ∆Vpeak_Ao (sensitivity, 91.7%; specificity, 88.9%; positive predictive value, 84.6%; negative predictive value, 94.1%). Volume expansion-induced changes in stroke volume correlated with the ∆Vpeak_Ca and ∆Vpeak_Ao before volume expansion (ρ of 0.70 and 0.61, respectively; p < .001 for both).Conclusions: Analysis of respiratory changes in carotid and aortic blood flows are accurate methods for predicting fluid responsiveness in children under invasive mechanical ventilation.
ObjectiveRenal resistive index (RRI) and renal pulsatility index (RPI) are Doppler-based variables proposed to assess renal perfusion at the bedside in critically ill patients. This study aimed to assess the accuracy of such variables to predict acute kidney injury (AKI) in mechanically ventilated children.DesignProspective single-center observational studySettingPediatric intensive care unit of a quaternary care teaching hospital.Patients84 children under controlled ventilation (median age of 5.1 months and weight of 6.6 kg).InterventionsConsecutive children underwent renal Doppler ultrasound examination within 24 hours of invasive mechanical ventilation. Renal resistive index (RRI) and renal pulsatility index (RPI) were measured. The primary outcome was severe AKI (KDIGO stage 2 or 3) on day 3. Secondary outcomes included the persistence of severe AKI on day 5.ResultsOn day 3, 22 patients were classified as having AKI (any stage), of which 12 were severe. RRI could effectively predict severe AKI (area under the ROC curve [AUC] 0.94; 95% CI 0.86 – 0.98; p < 0.001) as well as RPI (AUC 0.86; 95% CI 0.76 – 0.92; p < 0.001). The AUC of the IRR was significantly greater than that obtained from the RPI (p = 0.023). The optimal cutoff for RRI was 0.85 (sensitivity, 91.7%; specificity, 84.7%; positive predictive value, 50.0%; and negative predictive value 98.4%). Similar results were obtained when the accuracy to predict AKI on day 5 was assessed. Significant correlations were observed between RRI and estimated glomerular filtration rate at enrollment (ρ = -0.495, p<0.001) and on day 3 (ρ = -0.467, p <0.001).ConclusionsRenal Doppler ultrasound may be a promising tool to predict AKI in critically ill children under invasive mechanical ventilation.
doi: medRxiv preprint NOTE: This preprint reports new research that has not been certified by peer review and should not be used to guide clinical practice.
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