Change in Carotid Blood Flow and Carotid Corrected Flow Time Assessed by Novice Sonologists Fails to Determine Fluid Responsiveness in Spontaneously Breathing Intensive Care Unit Patients.
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SUBMITTER: Abbasi A
PROVIDER: S-EPMC7771259 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:In patients with acute circulatory failure, the primary goal of volume expansion is to increase cardiac output. However, this expected effect is inconstant, so that in many instances, fluid administration does not result in any haemodynamic benefit. In such cases, fluid could only exert some deleterious effects. It is now well demonstrated that excessive fluid administration is harmful, especially during acute respiratory distress syndrome and in sepsis or septic shock. This is the reason why some tests and indices have been developed in order to assess "fluid responsiveness" before deciding to perform volume expansion. While preload markers have been used for many years for this purpose, they have been repeatedly shown to be unreliable, which is mainly related to physiological issues. As alternatives, "dynamic" indices have been introduced. These indices are based upon the changes in cardiac output or stroke volume resulting from various changes in preload conditions, induced by heart-lung interactions, postural manoeuvres or by the infusion of small amounts of fluids. The haemodynamic effects and the reliability of these "dynamic" indices of fluid responsiveness are now well described. From their respective advantages and limitations, it is also possible to describe their clinical interest and the clinical setting in which they are applicable.
| S-EPMC7333112 | biostudies-literature
Project description:OBJECTIVES:Adequate assessment of fluid responsiveness in shock necessitates correct interpretation of hemodynamic changes induced by preload challenge. This study evaluates the accuracy of point-of-care Doppler ultrasound assessment of the change in carotid corrected flow time induced by a passive leg raise maneuver as a predictor of fluid responsiveness. Noninvasive cardiac output monitoring (NICOM, Cheetah Medical, Newton Center, MA) system based on a bioreactance method was used. DESIGN:Prospective, noninterventional study. SETTING:ICU at a large academic center. PATIENTS:Patients with new, undifferentiated shock, and vasopressor requirements despite fluid resuscitation were included. Patients with significant cardiac disease and conditions that precluded adequate passive leg raising were excluded. INTERVENTIONS:Carotid corrected flow time was measured via ultrasound before and after a passive leg raise maneuver. Predicted fluid responsiveness was defined as greater than 10% increase in stroke volume on noninvasive cardiac output monitoring following passive leg raise. Images and measurements were reanalyzed by a second, blinded physician. The accuracy of change in carotid corrected flow time to predict fluid responsiveness was evaluated using receiver operating characteristic analysis. MEASUREMENTS AND MAIN RESULTS:Seventy-seven subjects were enrolled with 54 (70.1%) classified as fluid responders by noninvasive cardiac output monitoring. The average change in carotid corrected flow time after passive leg raise for fluid responders was 14.1?±?18.7?ms versus -4.0?±?8?ms for nonresponders (p < 0.001). Receiver operating characteristic analysis demonstrated that change in carotid corrected flow time is an accurate predictor of fluid responsiveness status (area under the curve, 0.88; 95% CI, 0.80-0.96) and a 7?ms increase in carotid corrected flow time post passive leg raise was shown to have a 97% positive predictive value and 82% accuracy in detecting fluid responsiveness using noninvasive cardiac output monitoring as a reference standard. Mechanical ventilation, respiratory rate, and high positive end-expiratory pressure had no significant impact on test performance. Post hoc blinded evaluation of bedside acquired measurements demonstrated agreement between evaluators. CONCLUSIONS:Change in carotid corrected flow time can predict fluid responsiveness status after a passive leg raise maneuver. Using point-of-care ultrasound to assess change in carotid corrected flow time is an acceptable and reproducible method for noninvasive identification of fluid responsiveness in critically ill patients with undifferentiated shock.
| S-EPMC6774608 | biostudies-literature
Project description:BackgroundDynamic parameters used for predicting fluid responsiveness require special equipment and are minimally invasive. Therefore, recent interest in the use of carotid artery ultrasound parameters, such as carotid corrected flow time (FTc) and peak velocity variation (ΔVpeak) has grown. Therefore, we performed this systematic review and meta-analysis to assess the ability of carotid FTc and/or ΔVpeak to accurately predict fluid responsiveness.MethodsWe searched the PubMed and Embase databases for articles evaluating the diagnostic accuracy of carotid FTc or ΔVpeak for predicting fluid responsiveness. Two independent authors performed the search and selected studies published until May 2022. The studies were assessed for the inclusion and exclusion criteria using Rayyan (Rayyan Systems Inc., 2022).ResultsTen studies (n=438) that fulfilled the inclusion criteria were selected. Studies were divided into those assessing carotid FTc and those assessing carotid ΔVpeak. Five studies (six datasets) assessed FTc. The pooled sensitivity and specificity of carotid FTc were 0.76 and 0.88, respectively. The summary receiver operating characteristic (SROC) curve for carotid FTc had an area under the curve (AUC) of 0.9092, with a Q value of 0.8412. Seven studies calculated carotid ΔVpeak. The pooled sensitivity and specificity for ΔVpeak were 0.83 and 0.81, respectively. The SROC curve had an AUC of 0.8941 and a Q value of 0.8250.ConclusionsOur meta-analysis showed that both carotid FTc and ΔVpeak are useful for predicting fluid responsiveness in anesthesia and critical care settings with good specificity and sensitivity.
| S-EPMC10244609 | biostudies-literature
Project description:Predicting fluid responsiveness in patients under mechanical ventilation with low tidal volume (VT) is challenging. This study evaluated the ability of carotid corrected flow time (FTc) assessed by ultrasound for predicting the fluid responsiveness during low VT ventilation. Patients under postoperative mechanical ventilation and clinically diagnosed with hypovolemia were enrolled. Carotid FTc and pulse pressure variation (PPV) were measured at VT of 6 and 10 mL/kg predicted body weight (PBW). FTc was calculated using both Bazett's (FTcB) and Wodey's (FTcW) formulas. Fluid responsiveness was defined as a ≥15% increase in the stroke volume index assessed by FloTrac/Vigileo monitor after administration of 8 mL/kg of balanced crystalloid. Among 36 patients, 16 (44.4%) were fluid responders. The areas under the receiver operating characteristic curves (AUROCs) for the FTcB at VT of 6 and 10 mL/kg PBW were 0.897 (95% confidence interval [95% CI]: 0.750-0.973) and 0.895 (95% CI: 0.748-0.972), respectively. The AUROCs for the FTcW at VT of 6 and 10 mL/kg PBW were 0.875 (95% CI: 0.722-0.961) and 0.891 (95% CI: 0.744-0.970), respectively. However, PPV at VT of 6 mL/kg PBW (AUROC: 0.714, 95% CI: 0.539-0.852) showed significantly lower accuracy than that of PPV at VT of 10 mL/kg PBW (AUROC: 0.867, 95% CI: 0.712-0.957; p = 0.034). Carotid FTc can predict fluid responsiveness better than PPV during low VT ventilation. However, further studies using automated continuous monitoring system are needed before its clinical use.
| S-EPMC8234831 | biostudies-literature
Project description:Patients who increase stoke volume or cardiac index more than 10 or 15% after a fluid challenge are usually considered fluid responders. Assessment of fluid responsiveness prior to volume expansion is critical to avoid fluid overload, which has been associated with poor outcomes. Maneuvers to assess fluid responsiveness are well established in mechanically ventilated patients; however, few studies evaluated maneuvers to predict fluid responsiveness in spontaneously breathing patients. Our objective was to perform a systematic review of literature addressing the available methods to assess fluid responsiveness in spontaneously breathing patients. Studies were identified through electronic literature search of PubMed from 01/08/2009 to 01/08/2016 by two independent authors. No restrictions on language were adopted. Quality of included studies was evaluated with Quality Assessment of Diagnostic Accuracy Studies tool. Our search strategy identified 537 studies, and 9 studies were added through manual search. Of those, 15 studies (12 intensive care unit patients; 1 emergency department patients; 1 intensive care unit and emergency department patients; 1 operating room) were included in this analysis. In total, 649 spontaneously breathing patients were assessed for fluid responsiveness. Of those, 340 (52%) were deemed fluid responsive. Pulse pressure variation during the Valsalva maneuver (?PPV) of 52% (AUC ± SD: 0.98 ± 0.03) and passive leg raising-induced change in stroke volume (?SV-PLR) > 13% (AUC ± SD: 0.96 ± 0.03) showed the highest accuracy to predict fluid responsiveness in spontaneously breathing patients. Our systematic review indicates that regardless of the limitations of each maneuver, fluid responsiveness can be assessed in spontaneously breathing patients. Further well-designed studies, with adequate simple size and power, are necessary to confirm the real accuracy of the different methods used to assess fluid responsiveness in this population of patients.
| S-EPMC5807252 | biostudies-literature
Project description:ObjectivesInferior vena cava collapsibility (cIVC) measured by point-of-care ultrasound (POCUS) has been proposed as a noninvasive means of assessing fluid responsiveness. We aimed to prospectively evaluate the performance of a 25% cIVC cutoff value to detect fluid responsiveness among spontaneously breathing intensive care unit (ICU) patients when assessed with POCUS by novice versus expert physician sonologists.MethodsProspective observational study of spontaneously breathing ICU patients. Fluid responsiveness was defined as a >10% increase in cardiac index following a 500 mL fluid bolus, measured by bioreactance. Novice sonologist measured cIVC with POCUS. Their measurements were later compared to an expert physician sonologist who independently reviewed the POCUS images and assessed cIVCs.ResultsOf the 85 participants, 44 (52%) were fluid responders. A 25% cIVC cutoff value performed better when assessed by expert sonologists than novice physician sonologists (receiver-operator characteristic curve, ROC = 0.82 [0.74-0.88] vs ROC = 0.69 [0.60-0.77]).ConclusionsA 25% cIVC cutoff value measured by POCUS detects fluid responsiveness. However, the experience of the physician sonologist affects test performance and should be considered when interpreting and clinically using cIVC to direct intravenous fluid resuscitation.
| S-EPMC7153972 | biostudies-literature
Project description:BackgroundMethods to guide fluid therapy in spontaneously breathing patients are scarce. No studies have reported the accuracy of end-tidal CO2 (ET-CO2) to predict volume responsiveness in these patients. We sought to evaluate the ET-CO2 gradient (?ET-CO2) after a passive leg rise (PLR) maneuver to predict volume responsiveness in spontaneously breathing healthy adults.MethodsWe conducted a prospective study in healthy adult human volunteers. A PLR maneuver was performed and cardiac output (CO) was measured by transthoracic echocardiography. ET-CO2 was measured with non-invasive capnographs. Volume responsiveness was defined as an increase in cardiac output (CO) >?12% at 90 s after PLR.ResultsOf the 50 volunteers, 32% were classified as volume responders. In this group, the left ventricle outflow tract velocity time integral (VTILVOT) increased from 17.9?±?3.0 to 20.4?±?3.4 (p?=?0.0004), CO increased from 4.4?±?1.5 to 5.5?±?1.6 (p?=?0.0), and ET-CO2 rose from 32 ±?4.84 to 33 ±?5.07 (p?=?0.135). Within the entire population, PLR-induced percentage ?CO was not correlated with percentage ?ET-CO2 (R2?=?0.13; p?=?0.36). The area under the receiver operating curve for the ability of ET-CO2 to discriminate responders from non-responders was of 0.67?±?0.09 (95% CI 0.498-0.853). A ?ET-CO2???2 mmHg had a sensitivity of 50%, specificity of 97.06%, positive likelihood ratio of 17.00, negative likelihood ratio of 0.51, positive predictive value of 88.9%, and negative predictive value of 80.5% for the prediction of fluid responsiveness.Conclusions?ET-CO2 after a PLR has limited utility to discriminate responders from non-responders among healthy spontaneously breathing adults.
| S-EPMC6066588 | biostudies-literature
Project description:BackgroundWhether the respiratory changes of the inferior vena cava diameter during a deep standardized inspiration can reliably predict fluid responsiveness in spontaneously breathing patients with cardiac arrhythmia is unknown.MethodsThis prospective two-center study included nonventilated arrhythmic patients with infection-induced acute circulatory failure. Hemodynamic status was assessed at baseline and after a volume expansion of 500 mL 4% gelatin. The inferior vena cava diameters were measured with transthoracic echocardiography using the bi-dimensional mode on a subcostal long-axis view. Standardized respiratory cycles consisted of a deep inspiration with concomitant control of buccal pressures and passive exhalation. The collapsibility index of the inferior vena cava was calculated as [(expiratory-inspiratory)/expiratory] diameters.ResultsAmong the 55 patients included in the study, 29 (53%) were responders to volume expansion. The areas under the ROC curve for the collapsibility index and inspiratory diameter of the inferior vena cava were both of 0.93 [95% CI 0.86; 1]. A collapsibility index ??39% predicted fluid responsiveness with a sensitivity of 93% and a specificity of 88%. An inspiratory diameter?<?11 mm predicted fluid responsiveness with a sensitivity of 83% and a specificity of 88%. A correlation between the inspiratory effort and the inferior vena cava collapsibility was found in responders but was absent in nonresponder patients.ConclusionsIn spontaneously breathing patients with cardiac arrhythmias, the collapsibility index and inspiratory diameter of the inferior vena cava assessed during a deep inspiration may be noninvasive bedside tools to predict fluid responsiveness in acute circulatory failure related to infection. These results, obtained in a small and selected population, need to be confirmed in a larger-scale study before considering any clinical application.
| S-EPMC6072642 | biostudies-literature
Project description:The use of high-flow nasal oxygen is gaining popularity in apneic and spontaneously breathing adult patients during anesthesia. This prospective observational study evaluated the effect of high-flow nasal oxygen in maintaining adequate oxygenation and ventilation in spontaneously breathing pediatric patients with dynamic airway obstruction, undergoing tubeless airway surgery. Oxygenation was provided via an age-appropriate, high-flow nasal cannula at a flow rate of 2 L kg-1 min-1. Propofol and remifentanil were used to maintain anesthesia while preserving spontaneous respiration. We sought to determine the incidence and risk factors of rescue ventilation. Rescue ventilation with a face mask was performed when the pulse oximetry oxygen saturation was <90% or transcutaneous carbon dioxide was >80 mm Hg. In total, 27 patients were included in the final analysis. Median (interquartile range) of pulse oximetry and transcutaneous carbon dioxide were 100% (99%-100%) and 58.4 mm Hg (51.4-70.3 mm Hg), respectively. Altogether, 9 (33.3%) patients needed rescue ventilation during anesthesia. Of these, 7 patients (25.9%) developed oxygen desaturation (<90%) and 2 patients (7.4%) developed hypercarbia. Patients who required rescue ventilation were significantly younger (8.2 vs 28.8 months, P = .02) and required a longer anesthesia time (55.7 vs 41.0 minutes, P = .04) than those who did not. In conclusion, High-flow nasal oxygen is an alternative technique to maintain oxygenation in children undergoing airway surgeries. However, younger age and longer anesthesia time are significant risk factors leading to the requirement of rescue ventilation in these patients. Further studies with large sample size are required for clinical application of these techniques.
| S-EPMC9259177 | biostudies-literature
Project description:Oxygen extraction (OEF), oxidative metabolism (CMRO2), and blood flow (CBF) in the brain, as well as the coupling between CMRO2 and CBF due to cerebral autoregulation are fundamental to brain's health. We used a clinically feasible MRI protocol to assess impairments of these parameters in the perfusion territories of stenosed carotid arteries. Twenty-nine patients with unilateral high-grade carotid stenosis and thirty age-matched healthy controls underwent multi-modal MRI scans. Pseudo-continuous arterial spin labeling (pCASL) yielded absolute CBF, whereas multi-parametric quantitative blood oxygenation level dependent (mqBOLD) modeling allowed imaging of relative OEF and CMRO2. Both CBF and CMRO2 were significantly reduced in the stenosed territory compared to the contralateral side, while OEF was evenly distributed across both hemispheres similarly in patients and controls. The CMRO2-CBF coupling was significantly different between both hemispheres in patients, i.e. significant interhemispheric flow-metabolism uncoupling was observed in patients compared to controls. Given that CBF and CMRO2 are intimately linked to brain function in health and disease, the proposed easily applicable MRI protocol of pCASL and mqBOLD imaging might serve as a valuable tool for early diagnosis of potentially harmful cerebral hemodynamic and metabolic states with the final aim to select clinically asymptomatic patients who would benefit from carotid revascularization therapy.
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