Could Duplex carotid ultrasound be useful in the assessment of volume status and fluid responsiveness?

Predicting Fluid Responsiveness Using Carotid Ultrasound in Mechanically Ventilated Patients: A Systematic Review and Meta-Analysis of Diagnostic Test Accuracy Studies

BACKGROUND

A noninvasive and accurate method of determining fluid responsiveness in ventilated patients would help to mitigate unnecessary fluid administration. Although carotid ultrasound has been previously studied for this purpose, several studies have recently been published. We performed an updated systematic review and meta-analysis to evaluate the accuracy of carotid ultrasound as a tool to predict fluid responsiveness in ventilated patients.

METHODS

Studies eligible for review investigated the accuracy of carotid ultrasound parameters in predicting fluid responsiveness in ventilated patients, using sensitivity and specificity as markers of diagnostic accuracy (International Prospective Register of Systematic Reviews [PROSPERO] CRD42022380284). All included studies had to use an independent method of determining cardiac output and exclude spontaneously ventilated patients. Six bibliographic databases and 2 trial registries were searched. Medline, Embase, Emcare, APA PsycInfo, CINAHL, and the Cochrane Library were searched on November 4, 2022. Clinicaltrials.gov and Australian New Zealand Clinical Trials Registry were searched on February 24, 2023. Results were pooled, meta-analysis was conducted where possible, and hierarchical summary receiver operating characteristic models were used to compare carotid ultrasound parameters. Bias and evidence quality were assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) tool and the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) guidelines.

RESULTS

Thirteen prospective clinical studies were included (n = 648 patients), representing 677 deliveries of volume expansion, with 378 episodes of fluid responsiveness (58.3%). A meta-analysis of change in carotid Doppler peak velocity (∆CDPV) yielded a sensitivity of 0.79 (95% confidence interval [CI], 0.74-0.84) and a specificity of 0.85 (95% CI, 0.76-0.90). Risk of bias relating to recruitment methodology, the independence of index testing to reference standards and exclusionary clinical criteria were evaluated. Overall quality of evidence was low. Study design heterogeneity, including a lack of clear parameter cutoffs, limited the generalizability of our results.

CONCLUSIONS

In this meta-analysis, we found that existing literature supports the ability of carotid ultrasound to predict fluid responsiveness in mechanically ventilated adults. ∆CDPV may be an accurate carotid parameter in certain contexts. Further high-quality studies with more homogenous designs are needed to further validate this technology.

Evaluating corrected carotid flow time as a non-invasive parameter for trending cardiac output and stroke volume in cardiac surgery patients

PURPOSE

The corrected carotid flow time (ccFT) is derived from a pulsed-wave Doppler signal at the common carotid artery. Several equations are currently used to calculate ccFT. Its ability to assess the intravascular volume status non-invasively has recently been investigated. The purpose of this study was to evaluate the correlation and trending ability of ccFT with invasive cardiac output (CO) and stroke volume (SV) measurements.

METHODS

Eighteen cardiac surgery patients were included in this prospective observational study. ccFT measurements were obtained at three time points: after induction of anesthesia (T1), after a passive leg raise (T2), and post-bypass (T3). Simultaneously, CO and SV were measured by calibrated pulse contour analysis. Three different equations (Bazett, Chambers, and Wodey) were used to calculate ccFT. The correlation and percentage change in time (concordance) between ccFT and CO and between ccFT and SV were evaluated.

RESULTS

Mean ccFT values differed significantly for the three equations (p < 0.001). The correlation between ccFT and CO and between ccFT and SV was highest for Bazett's (ρ = 0.43, p < 0.0001) and Wodey's (ρ = 0.33, p < 0.0001) equations, respectively. Concordance between ΔccFT and ΔCO and between ΔccFT and ΔSV was highest for Bazett's (100%) and Wodey's (82%) equations, respectively. Subgroup analysis demonstrated that correlation and concordance between SV and ccFT improved when assessed within limited heart rate (HR) ranges.

CONCLUSION

The use of different ccFT equations leads to variable correlation and concordance rates between ccFT and CO/SV measurements. Bazett's equation acceptably tracked CO changes in time, while the trending capability of SV was poor.

Long-Term Functionality Prediction for First Time Ischemic Middle Cerebral Artery Stroke Patients Receiving Conventional Medical Treatment

BACKGROUND

Middle cerebral artery (MCA) ischemic stroke poses a major threat to human beings and prompts intravenous thrombolytic and/or thrombectomy management remains the gold standard treatment. However, not all MCA stroke patients fit in the inclusion and exclusion criteria that many patients only receive conventional medical therapy. We attempt to seek the baseline parameters that can effectively predict patients' long-term functionality, as well as hypothesizing that the carotid duplex derived resistance/pulsatility index might be capable of fulfilling this purpose.

METHODS

The 741 MCA ischemic stroke patients have been retrospectively recruited for the project. Under the initial screening, matching the inclusion and exclusion criteria, there are 471 participants to be enrolled in the study. The patients' basic information, along with outcome assessments, pre-admission Barthel index and NIHSS score, and pre- and post-treatment mRS are recorded. All statistical analyses were performed using R for Windows (version 3.6.3). The significance level was set at P < 0.05 for all analyses.

RESULTS

Of the 471 patients, 239 participants show a net mRS improvement, whereas the other 232 show deterioration. Hyperlipidaemia, chronic kidney disease, and dementia are related to long-term functionality improvement. The multivariate logistic regression analysis shows that right common carotid artery (CCA) resistance index (RI) and ischemic heart disease play a significant role in favourable outcome functionality. The ROC and Youden Index models are formulated, and it shows that Barthel Index and the NIHSS are most significant in the outcome measurement group (AUC: 0.675, 0.653; cut-off point: 57.5, 3.5, respectively). The right-side CCA RI is the solely important outcome predictor for the baseline carotid duplex study (AUC: 0.5; cut-off point: 0.785).

CONCLUSION

The favourable long-term functionality of MCA ischemic stroke patients receiving conventional medical treatment seems to correlate fairly with pre-admission NIHSS and Barthel index scores. Underlying hyperlipidaemia, chronic kidney disease, and dementia are conversely associated with favourable long-term capability. Moreover, the value of CCA RI appears to significantly alter the long-term outcomes in this group of patients.