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Background: Fluid boluses are used in hemodynamically unstable patients with presumed hypovolemia, to improve tissue perfusion, in the perioperative period. Now less invasive methods, such as pulse pressure variation (PPV) and stroke volume variation (SVV) are increasingly being used. We investigated correlation between carotid and brachial artery velocity time integral (VTI) and compared both with PPV and SVV. Methods: We recruited 27 patients undergoing supra-major abdominal surgeries. When indicated (hypotension or increased lactate), a fluid bolus was given after measuring carotid and brachial artery VTI, PPV, and SVV. The change in SV was noted and patients were categorized as responders if the SV increased by >15%. We performed Bland Altman Agreement and calculated best sensitivity and specificity for the parameters. Results: Patients were found to be fluid responders on 29 instances. The correlation between PPV, SVV, carotid and brachial artery VTI was poor and the limits of agreement between them were wide. The Area under Curve (AUC) for PPV was 0.69, for SVV was 0.63, while those of Carotid and Brachial artery VTI (TAP and flow) were (0.53 and 0.54 for carotid) and (0.51 and 0.56 for brachial) respectively. Conclusion: We found poor agreement and weak correlation between both VTi (TAP and flow) measured at carotid and brachial arteries, suggesting that the readings at brachial vessel cannot be used interchangeably with those at carotid artery. The PPV and SVV were better than these parameters for predicting fluid responsiveness; however, their predictive ability (AUROC), sensitivity and specificity were much lower than previously reported. Further studies in this area are therefore required (CTRI Reg No: CTRI/2017/08/009243). [ABSTRACT FROM AUTHOR]

Background: Tidal volume challenge pulse pressure variation (TVC-PPV) is considered one of the recent reliable dynamic indices of fluid responsiveness (FR); also, passive leg raising (PLR)-induced changes in cardiac output (CO) detected by echocardiography are considered a reliable reversible self-fluid challenge test; many patients share eligibility for both tests. Objectives: The study aimed to compare the sensitivity and specificity of both tests for the prediction of FR in mechanically ventilated patients with hemodynamic instability. Methods: We studied 46 patients. Hemodynamic parameters including PPV and CO (detected by velocity time integral (VTI) using echocardiography) recorded at tidal volume (VT) of 6 mL/kg/ideal body weight (IBW) in semi-recumbent position then recorded again after one-minute increase in TV from 6 to 8 mL/kg/IBW then recorded with PLR at TV of 6 mL/kg/IBW and finally with actual volume expansion in semi-recumbent position by 4 ml/kg bolus of crystalloid solution to define actual responders with increase of cardiac output of 15% or more. Results: Sixteen patients were responders, and thirty patients were nonresponders; responders had significant increase in PPV with TVC 6 to 8 ml/kg/IBW with best cutoff value of 3.5 with a sensitivity of 93.8% and a specificity of 93.9%. PLR test-induced changes in CO had a sensitivity of 93.9% and a specificity of 86.7% with statistically best cutoff value of 6.5% increase in CO, but sensitivity was 75% at cutoff value of 10% increase in CO. Other parameters like PPV, PPV changes with PLR test, and PPV changes with fluid expansion were less sensitive indicators. Conclusion: FR in patients with hemodynamic instability and mechanically ventilated with low tidal volume strategy can be efficiently predicted when PPV increases more than 3.5 with tidal volume challenge and when PLR induces 6.5% increase in CO monitored through VTI method by Doppler echocardiography, and both tests are equally reliable. [ABSTRACT FROM AUTHOR]

Introduction: This study was conducted to assess fluid responsiveness in critically ill patients to avoid various complications of fluid overload. Material and methods: This study was done in an ICU of a tertiary care hospital after approval from the institute ethical committee over 18 months. A total of 54 consenting adult patients were included in the study. Patients were hemodynamically unstable requiring mechanical ventilation, had acute circulatory failure, or those with at least one clinical sign of inadequate tissue perfusion. All patients were ventilated using tidal volume of 6--8 mL/kg, RR--12--15/minutes, positive end expiratory pressure (PEEP)--5 cm of water, and plateau pressure was kept below 30 cm water. They were sedated throughout the study. The arterial line and the central venous catheter were placed and connected to Vigileo-FloTrac transducer (Edward Lifesciences). Patients were classified into responder and nonresponder groups on the basis of the cardiac index (CI) after fluid challenge of 10 mL/kg of normal saline over 30 minutes. Pulse pressure variation (PPV), stroke volume variation (SVV), and systolic pressure variation (SPV) were assessed and compared at baseline, 30 minutes, and 60 minutes. Results: In our study we found that PPV and SVV were significantly lower among responders than nonresponders at 30 minutes and insignificant at 60 minutes. Stroke volume variation was 10.28 ± 1.76 in the responder compared to 12.28 ± 4.42 (p = 0.02) at 30 minutes and PPV was 15.28 ± 6.94 in responders while it was 20.03 ± 4.35 in nonresponders (p = 0.01). We found SPV was insignificant at all time periods among both groups. Conclusion: We can conclude that initial assessment for fluid responsiveness in critically ill mechanically ventilated patients should be based on PPV and SVV to prevent complications of fluid overload and their consequences. [ABSTRACT FROM AUTHOR]

The last decades have been characterized by a continuous evolution of hemodynamic monitoring techniques from intermittent toward continuous and real-time measurements and from an invasive towards a less invasive approach. The latter approach uses ultrasounds and pulse contour analysis techniques that have been developed over the last 15 years. During the same period, the concept of prediction of fluid responsiveness has also been developed and dynamic indices such as pulse pressure variation, stroke volume variation, and the real-time response of cardiac output to passive leg raising or to end-expiration occlusion, can be easily obtained and displayed with the minimally invasive techniques. In this article, we review the main hemodynamic monitoring devices currently available with their respective advantages and drawbacks. We also present the current viewpoint on how to choose a hemodynamic monitoring device in the most severely ill patients and especially in patients with circulatory shock. [ABSTRACT FROM AUTHOR]