Stroke Volume Variation Research Articles

Efficacy of Stroke Volume Variation-guided Fluid Management of Patients undergoing Off-pump Coronary Artery Bypass Grafting: An Observational Comparative Study between Open and Closed Chest

Introduction: Functional haemodynamic monitoring using dynamic parameter such as Stroke Volume Variation (SVV), based on pulse contour analysis, helps in predicting fluid responsiveness in off pump Coronary Artery Bypass Grafting (CABG) surgery. This allows adequate volume replacement to achieve optimal cardiac performance. Aim: To evaluate the efficacy of SVV in predicting volume responsiveness and effect on haemodynamic variable in patients undergoing off pump CABG in both closed and open chest. Materials and Methods: This single-centre, non randomised observational study was conducted at a tertiary medical college and hospital (LokmanyaTilak Municipal Medical College and General Hospital) Mumbai, Maharashtra, India, from December 2016 to December 2018. A total of 34 patients undergoing elective off pump CABG were included. Haemodynamic measurements Stroke Volume (SV), Cardiac Output (CO), Cardiac Index (CI), and SVV, were recorded with the transducer positioned at the level of midaxillary line. If the SVV was equal to or higher than 12, 100 mL fluid aliquot was given to patients. Endpoints for fluid aliquots was increase in CO by 15%, decrease in SVV of less than 12 or an increase Central Venous Pressure (CVP) upto 15 millimeter of mercury (mmHg). Number of times SVV above 12 during the procedure was recorded. SVV was considered as fluid responsive “if there was an increase in SV by 5%”. Statistical analysis was done using Student’s t-test (two tailed, dependent) on continuous parameters. The p-value <0.05, was considered significant. Results: Out of 103 events of rise in SVV, 65 (63.1%) occurred when chest was open and 38 (36.9%) while chest was closed. The SVV-guided fluid response was 76.3% in closed chest and 75.4% in open chest and there was no significant difference. (p-value=0.91). There was a significant increase in SV (p-value<0.01), CO (p-value=0.04), and significant decrease in SVV (p-value<0.01) and heart rate (p-value<0.01) after fluid loading in the responsive group when compared with non responsive group. There was no statistically significant difference between percentage change in SV, CO, CI, SBP, DBP, MAP and CVP between closed and open chest conditions after fluid replacement. Conclusion: SVV is not affected by open or closed chest conditions in mechanically ventilated patients undergoing CABG and can be used as a guide for fluid replacement. Weather open or closed chest conditions, few patients do not respond to fluid replacement when SVV are more than 12 by an increase in SV, cardiac output or CI, the cause of which remains to be determined.

Effect of Goal-Directed Intraoperative Fluid Therapy on Duration of Hospital Stay and Postoperative Complications in Patients Undergoing Excision of Large Supratentorial Tumors.

Optimal fluid management during neurosurgery is controversial. Evidences suggest that goal-directed fluid therapy (GDFT) can improve postoperative outcome. This study aimed to assess the intraoperative use of GDFT on the duration of hospital stay and postoperative complications in patients undergoing craniotomy for large supratentorial tumors. Forty patients of 18-65 years age undergoing large supratentorial tumor surgery were prospectively randomized into two groups. Control-group received fluid regimen based on routine hemodynamic monitoring, whereas patients belonging to GDFT group received fluid based on stroke volume variation (SVV)-guided therapy. A colloid bolus of 250 ml 6% hydroxyl ethyl starch was given, if the SVV was more than 12% in the GDFT group. Hemodynamic parameters, such as blood pressure and heart rate, and dynamic parameters, such as cardiac index, stroke volume index, and SVV, were recorded at different time intervals. The total amount of fluid required was significantly lower in GDFT (P = 0.003) group as compared to the Control group. Intraoperative complications were significantly lower in GDFT group (P = 0.005), but the incidence of tight brain was significantly higher in the control group. The duration of hospital stay (P = 0.07) and incidence of postoperative complications (P = 0.32) were lower in GDFT group. Neurological outcomes at-discharge were similar in both the groups. This study did not show any benefit of GDFT over conventional intraoperative fluid therapy in terms of incidence of postoperative complications, hospital and ICU stay, and Glasgow outcome scores at-discharge in patients undergoing craniotomy for excision of large supratentorial tumors. However, the use of GDFT leads to better perioperative fluid management and brain relaxation scores. CTRI/2016/10/007350.

Validation of stroke volume variation assessed by electrical cardiometry to predict fluid responsiveness in patients undergoing coronary artery bypass surgery after closure of the sternum: an observational study

Validation of stroke volume variation assessed by electrical cardiometry to predict fluid responsiveness in patients undergoing coronary artery bypass surgery after closure of the sternum: an observational study

Performance of non-invasive stroke volume variation during passive leg raising as a predictor of hypotension following induction of spinal anesthesia for elective cesarean delivery: a single cohort study

BackgroundSpinal anesthesia for cesarean delivery is accompanied by hypotension in up to 70% of cases. To date, there is no gold standard for predicting hypotension after spinal anesthesia for cesarean delivery. The Clearsight™ device is a non-invasive system that uses a digital cuff to calculate stroke volume. We hypothesized that stroke volume variation induced with passive leg raising before spinal anesthesia for elective cesarean delivery could predict the occurrence of hypotension. MethodsWe conducted a prospective observational study, including third trimester parturients undergoing elective cesarean delivery with spinal anesthesia. We analyzed the stroke volume variation performance for predicting hypotension. Stroke volume was collected in the semi-recumbent position (baseline) and during passive leg raising before spinal anesthesia. Systolic arterial blood pressure measurement was followed for 15 min after spinal anesthesia. Hypotension was defined as a ≥20% decrease from the baseline measurement. All parturients received appropriate hypotension prophylaxis. ResultsData from 42 parturients were analyzed. Hypotension occurred in 45%. The area-under-the curve for predicting hypotension using the stroke volume variation was 0.83 (95% CI 0.68 to 0.98; P=0.001). The best cut-off value for predicting hypotension was 7%, having a sensitivity of 87% (95% CI 0.70 to 0.99) and a specificity of 83% (95% CI 0.69 to 0.97). ConclusionIn our study of third trimester parturients undergoing cesarean delivery and receiving appropriate hypotension prophylaxis, a digital non-invasive monitoring device of stroke volume variation analysis was useful for predicting the occurrence of hypotension after spinal anesthesia.

Stroke Volume Variation-Guided Goal-Directed Fluid Therapy Did Not Significantly Reduce the Incidence of Early Postoperative Complications in Elderly Patients Undergoing Minimally Invasive Esophagectomy: A Randomized Controlled Trial

Study Objective: This study aimed to investigate whether stroke volume variation (SVV)-guided goal-directed therapy (GDT) can improve postoperative outcomes in elderly patients undergoing minimally invasive esophagectomy (MIE) compared with conventional care.Design: A prospective, randomized, controlled study.Setting: A single tertiary care center with a study period from November 2017 to December 2018.Patients: Patients over 65 years old who were scheduled for elective MIE.Interventions: The GDT protocol included a baseline fluid supplement of 7 ml/kg/h Ringer's lactate solution and SVV optimization using colloid boluses assessed by pulse-contour analysis (PiCCO™). When SVV exceeded 11%, colloid was infused at a rate of 50 ml per minute; if SVV returned below 9% for at least 2 minutes, then colloid was stopped.Measurements: The primary outcome was the incidence of postoperative complications before discharge, as assessed using a predefined list, including postoperative anastomotic leakage, postoperative hoarseness, postoperative pulmonary complications, chylothorax, myocardial injury, and all-cause mortality.Main Results: Sixty-five patients were included in the analysis. The incidence of postoperative complications between groups was similar (GDT 36.4% vs. control 37.5%, P = 0.92). The total fluid volume was not significantly different between the two groups (2,192 ± 469 vs. 2,201 ± 337 ml, P = 0.92). Compared with those in the control group (n = 32), patients in the GDT group (n = 33) received more colloids intraoperatively (874 ± 369 vs. 270 ± 67 ml, P <0.05) and less crystalloid fluid (1,318 ± 386 vs. 1,937 ± 334 ml, P <0.05).Conclusion: The colloid-based SVV optimization during GDT did not significantly reduce the incidence of early postoperative complications after minimally invasive esophagectomy in elderly patients.Clinical Trial Number and Registry URL: ChiCTR-INR-17013352; http://www.chictr.org.cn/showproj.aspx?proj=22883

Clinical value of point of care ultrasound on cardiac output and volume responsiveness in patients with septic shock

To assess the value of point of care ultrasound on cardiac output (CO) and volume responsiveness in patients with septic shock. Twenty-four mechanical ventilation patients with septic shock who needed pulse-indicated continuous cardiac output (PiCCO) monitoring in the department of critical care medicine of Zhengzhou University People's Hospital, Henan Provincial People's Hospital from November 25, 2020 to April 30, 2021 were selected as the subjects, the patient's basic information and laboratory test results were recorded. PiCCO was used as standard to monitor CO and stroke volume variability (SVV) at 0, 2, 6, 12, 24 and 48 hours. At the same time, point of care transthoracic echocardiography (TTE) was used to measure velocity time integral (VTI) and inferior vena cava diameter (dIVC), the CO, VTI variation rate (ΔVTI) and dIVC variation rate (ΔdIVC) were calculated. Then, using the value monitored by PiCCO as the standard, the consistency and correlation analysis were carried out between point of care ultrasound with PiCCO. Twenty-two out of 24 patients obtained satisfactory ultrasound Doppler images, the heart rate (HR), mean arterial pressure (MAP) and body temperature of the enrolled patients were consistent with the pathophysiological characteristics of septic shock. With the extension of treatment time, HR and CO both gradually decreased, and MAP gradually increased, reaching a peak or trough at 48 hours after admission. The difference were statistically significant compared with the time of admission [HR (bpm): 90.36±15.35 vs. 116.82±19.82, MAP (mmHg, 1 mmHg = 0.133 kPa): 87.82±11.06 vs. 58.82±9.85, CO (L/min): 4.80±0.56 vs. 6.78±1.31, all P < 0.05]. The CO obtained by PiCCO and point of care ultrasound had good agreement [5.36 (4.78, 6.33) L/min and 5.21 (4.88, 6.35) L/min, respectively], the average difference value at each time point was (-0.02±0.69) L/min, the 95% agreement limit range was -1.35-1.34, and there was a high degree of correlation (rs = 0.800, P < 0.001); The SVV by PiCCO and the ΔdIVC by point of care ultrasound were in good agreement [18.00% (14.00%, 24.00%) and 21.00% (14.00%, 25.75%), respectively], the average difference value at the time point was (-3.16±6.89)%, the 95% agreement limit range was -16.89-10.54, and there was a moderate correlation (rs = 0.702, P < 0.001); The SVV by PiCCO and the ΔVTI by point of care ultrasound were in good agreement [18.00% (14.00%, 24.00%) and 16.00% (11.25%, 20.75%), respectively], the average difference value at each time point was (13.03±14.75)%, and the 95% agreement limit range was 1.72-27.78, and there was a high correlation (rs = 0.918, P < 0.001). Point of care ultrasound can accurately assess CO and volume responsiveness of patients with septic shock, and the ΔVTI is better than the ΔdIVC in assessing volume responsiveness.

Changes in stroke volume induced by lung recruitment maneuver can predict fluid responsiveness during intraoperative lung-protective ventilation in prone position

BackgroundThe present study aimed to evaluate the reliability of hemodynamic changes induced by lung recruitment maneuver (LRM) in predicting stroke volume (SV) increase after fluid loading (FL) in prone position.MethodsThirty patients undergoing spine surgery in prone position were enrolled. Lung-protective ventilation (tidal volume, 6–7 mL/kg; positive end-expiratory pressure, 5 cmH2O) was provided to all patients. LRM (30 cmH2O for 30 s) was performed. Hemodynamic variables including mean arterial pressure (MAP), heart rate, SV, SV variation (SVV), and pulse pressure variation (PPV) were simultaneously recorded before, during, and at 5 min after LRM and after FL (250 mL in 10 min). Receiver operating characteristic curves were generated to evaluate the predictability of SVV, PPV, and SV decrease by LRM (ΔSVLRM) for SV responders (SV increase after FL > 10%). The gray zone approach was applied for ΔSVLRM.ResultsAreas under the curve (AUCs) for ΔSVLRM, SVV, and PPV to predict SV responders were 0.778 (95% confidence interval: 0.590–0.909), 0.563 (0.371–0.743), and 0.502 (0.315–0.689), respectively. The optimal threshold for ΔSVLRM was 30% (sensitivity, 92.3%; specificity, 70.6%). With the gray zone approach, the inconclusive values ranged 25 to 75% for ΔSVLRM (including 50% of enrolled patients).ConclusionIn prone position, LRM-induced SV decrease predicted SV increase after FL with higher reliability than traditional dynamic indices. On the other hand, considering the relatively large gray zone in this study, future research is needed to further improve the clinical significance.Trial registrationUMIN Clinical Trial Registry UMIN000027966. Registered 28th June 2017.

The effect of the volemic and cardiac status on brain oxygenation in patients with subarachnoid hemorrhage: a bi-center cohort study

BackgroundFluid management in patients after subarachnoid hemorrhage (SAH) aims at the optimization of cerebral blood flow and brain oxygenation. In this study, we investigated the effects of hemodynamic management on brain oxygenation by integrating advanced hemodynamic and invasive neuromonitoring.MethodsThis observational cohort bi-center study included data of consecutive poor-grade SAH patients who underwent pulse contour cardiac output (PiCCO) monitoring and invasive neuromonitoring. Fluid management was guided by the transpulmonary thermodilution system and aimed at euvolemia (cardiac index, CI ≥ 3.0 L/min/m2; global end-diastolic index, GEDI 680–800 mL/m2; stroke volume variation, SVV < 10%). Patients were managed using a brain tissue oxygenation (PbtO2) targeted protocol to prevent brain tissue hypoxia (BTH, PbtO2 < 20 mmHg). To assess the association between CI and PbtO2 and the effect of fluid challenges on CI and PbtO2, we used generalized estimating equations to account for repeated measurements.ResultsAmong a total of 60 included patients (median age 56 [IQRs 47–65] years), BTH occurred in 23% of the monitoring time during the first 10 days since admission. Overall, mean CI was within normal ranges (ranging from 3.1 ± 1.3 on day 0 to 4.1 ± 1.1 L/min/m2 on day 4). Higher CI levels were associated with higher PbtO2 levels (Wald = 14.2; p < 0.001). Neither daily fluid input nor fluid balance was associated with absolute PbtO2 levels (p = 0.94 and p = 0.85, respectively) or the occurrence of BTH (p = 0.68 and p = 0.71, respectively). PbtO2 levels were not significantly different in preload dependent patients compared to episodes of euvolemia. PbtO2 increased as a response to fluid boluses only if BTH was present at baseline (from 13 ± 6 to 16 ± 11 mmHg, OR = 13.3 [95% CI 2.6–67.4], p = 0.002), but not when all boluses were considered (p = 0.154).ConclusionsIn this study a moderate association between increased cardiac output and brain oxygenation was observed. Fluid challenges may improve PbtO2 only in the presence of baseline BTH. Individualized hemodynamic management requires advanced cardiac and brain monitoring in critically ill SAH patients.

Utilization and Efficacy of Resuscitation Endpoints in Trauma and Burn Patients: A Review Article.

Shock is a sequelae in trauma and burn patients that substantially increases the risk for morbidity and mortality. The use of resuscitation endpoints allows for improved management of these patients, with the potential to prevent further morbidity/mortality. We conducted a review of the current literature on the efficacy of hemodynamic, metabolic, and regional resuscitation endpoints for use in trauma and burn patients. Hemodynamic endpoints included mean arterial pressure (MAP), heart rate (HR), urinary output (UO), compensatory reserve index (CRI), intrathoracic blood volume, and stroke volume variation (SVV). Metabolic endpoints measure cellular responses to decreased oxygen delivery and include serum lactic acid (LA), base deficit (BD), bicarbonate, anion gap, apparent strong ion difference, and serum pH. Mean arterial pressure, HR, UO, and LA are the most established markers of trauma and burn resuscitation. The evidence suggests LA is a superior metabolic endpoint marker. Newer resuscitation endpoint technologies such as point-of-care ultrasound (PoCUS), thromboelastography (TEG), and rotational thromboelastometry (ROTEM) may improve patient outcomes; however, additional research is needed to establish the efficacy in trauma and burn patients. The endpoints discussed have situational strengths and weaknesses and no single universal resuscitation endpoint has yet emerged. This review may increase knowledge and aid in guideline development. We recommend clinicians continue to integrate multiple endpoints with emphasis on MAP, HR, UO, LA, and BD. Future investigation should aim to standardize endpoints for each clinical presentation. The search for universal and novel resuscitation parameters in trauma and burns should also continue.

Changes in stroke volume variation and cardiac index during open major bowel surgery.

Stroke volume variation (SVV) is a dynamic indicator of preload, which is a determinant of cardiac output. Aims: Aim of this study was to evaluate the relationship between changes in SVV and cardiac index (CI) in patients with normal left ventricular function undergoing major open abdominal surgery. Patients undergoing major open abdominal surgery were monitored continuously with FloTrac® to measure SVV and CI along with standard monitoring. Both SVV and CI were noted at baseline and every 10 min thereafter till the end of surgery and were observed for concurrence between the measurements. 1800 pairs of measurement of SVV and CI were obtained from 60 patients. Mean SVV and CI (of all patients) measured at different time points of measurement showed that as SVV increased with time, the CI dropped correspondingly. When individual readings of CI and SVV were plotted against each other, the scatter was found to be wide, reiterating the lack of agreement between the two parameters (R2 = 0.035). SVV >13% suggesting hypovolemia was found at 207 time points. Of these, 175 had a CI >2.5 L/min/m2 and only 32 patients had a CI <2.5 L/min/m2. SVV, a dynamic index of fluid responsiveness can be used to monitor patients expected to have large fluid shifts during major abdominal surgery. It is very specific and has a high negative predictive value. When SVV increases, CI is usually maintained. Since many factors affect SVV and CI, any increase in SVV >13%, must be correlated with other parameters before administration of the fluid challenge.

Dynamic variables predict fluid responsiveness in pre-school and school children undergoing neurosurgery: a prospective observational study.

BackgroundThe evidence that plethysmographic variability index (PVI), pulse pressure variation (PPV), FloTrac/Vigileo-derived stroke volume variation (SVV), and Eadyn (dynamic arterial elastance) predict fluid responsiveness in children is limited by conflicting results. We aim to evaluate their accuracy and reliability to predict fluid responsiveness after induction in children aged 4–9 years undergoing major neurosurgery.MethodsChildren aged 4–9 years undergoing intracranial epileptic foci excision were enrolled. After the induction of anesthesia, fluid loading with 10 mL/kg of Ringer’s solution over 10 min was administered before surgical incision. PVI, PPV, SVV, and Eadyn were measured before and within 5 min after fluid loading. Respiratory variation in aortic blood flow peak velocity (∆Vpeak) >15% at baseline, measured using transthoracic echocardiography, identified fluid “responders”. The abilities of dynamic variables to predict an increase in mean arterial pressure (MAP) of >10% following fluid loading were also assessed.ResultsFourteen (31.8%) of forty-four patients were responders defined by a baseline ∆Vpeak >15%. Before fluid loading, only the PVI value was significantly different between R and NR (P=0.017). Baseline PVI showed fair diagnostic accuracy for fluid responsiveness, with an area under the curve (AUROC) of 0.735 and the cutoff value of 13%. The R group showed a significantly greater absolute change in PPV and SVV after fluid loading from baseline compared with the NR group (P=0.021 and 0.040, respectively). The absolute change in the PPV and SVV values from baseline was greater in R than those in NR (P=0.021 and 0.040, respectively). Twenty (45.5%) showed a MAP increase of >10% following fluid loading and were defined as responders. Baseline ∆Vpeak and SVV showed fair predictive values for a MAP increase of >10% (AUROC =0.758 and 0.715, respectively).ConclusionsPVI at baseline showed fair reliability to predict fluid responsiveness after anesthesia induction in mechanically ventilated children aged 4–9 years undergoing neurosurgery. Baseline ∆Vpeak and SVV were fairly predictive for an increase in MAP following fluid loading.

Should we use diastolic function parameters to determine preload responsiveness in cardiac surgery? A pilot study

BackgroundLeft ventricular (LV) diastolic function (DF) may play an important role in predicting fluid responsiveness. However, few studies assessed the role of diastolic function in predicting fluid responsiveness. The aim of this pilot study was to assess whether parameters of right and left diastolic function assessed with transesophageal echocardiography, including the mitral E/e′ ratio, is associated with fluid responsiveness among patients undergoing elective bypass graft surgery. We also sought to compare other methods of fluid responsiveness assessment, including echocardiographic and hemodynamic parameters, pulse pressure variation, and stroke volume variation (SVV) (arterial pulse contour analysis, Flotrac/Vigileo system).ResultsWe prospectively studied seventy patients undergoing coronary artery bypass grafting (CABG) monitored with a radial arterial catheter, transesophageal echocardiography (TEE), and a pulmonary artery catheter (for cardiac output measurements), before and after the administration of 500 mL of crystalloid over 10 min after the anesthetic induction. Thirteen patients were excluded (total of 57 patients). Fluid responsiveness was defined as an increase in cardiac index of ≥ 15%. There were 21 responders (36.8%) and 36 non-responders (63.2%). No difference in baseline pulsed wave Doppler echocardiographic measurements of any components of the mitral, tricuspid, and pulmonary and hepatic venous flows were found between responders and non-responders. There was no difference in MV tissue Doppler measurements between responders and non-responders, including E/e′ ratio (8.7 ± 4.1 vs. 8.5 ± 2.8 in responders vs. non-responders, P = 0.85). SVV was the only independent variable to predict an increase in cardiac index by multivariate analysis (P = 0.0208, OR = 1.196, 95% CI (1.028-1.393)).ConclusionsIn this pilot study, we found that no parameters of right and left ventricular diastolic function were associated with fluid responsiveness in patients undergoing CABG. SVV was the most useful parameter to predict fluid responsiveness.Trial registrationClinicalTrials.gov, NCT 02714244. Registered 21 March 2016—retrospectively registered.

Ability of dynamic preload indices to predict fluid responsiveness in a high femoral-to-radial arterial pressure gradient: a retrospective study.

BackgroundDynamic preload indices may predict fluid responsiveness in end-stage liver disease. However, their usefulness in patients with altered vascular compliance is uncertain. This study is the first to evaluate whether dynamic indices can reliably predict fluid responsiveness in patients undergoing liver transplantation with a high femoral-to-radial arterial pressure gradient (PG).MethodsEighty liver transplant recipients were retrospectively categorized as having a normal (n = 56) or high (n = 24, difference in systolic pressure ≥ 10 mmHg and/or mean pressure ≥ 5 mmHg) femoral-to-radial arterial PG, measured immediately after radial and femoral arterial cannulation. The ability of dynamic preload indices (stroke volume variation, pulse pressure variation [PPV], pleth variability index) to predict fluid responsiveness was assessed before the surgery. Fluid replacement of 500 ml of crystalloid solution was performed over 15 min. Fluid responsiveness was defined as ≥ 15% increase in the stroke volume index. The area under the receiver-operating characteristic curve (AUC) indicated the prediction of fluid responsiveness.ResultsFourteen patients in the normal, and eight in the high PG group were fluid responders. The AUCs for PPV in the normal, high PG groups and total patients were 0.702 (95% confidence interval [CI] 0.553–0.851, P = 0.008), 0.633 (95% CI 0.384–0.881, P = 0.295) and 0.667 (95% CI 0.537–0.798, P = 0.012), respectively. No other index predicted fluid responsiveness.ConclusionPPV can be used as a dynamic index of fluid responsiveness in patients with end-stage liver disease but not in patients with altered vascular compliance.

Impact of conventional vs. goal-directed fluid therapy on urethral tissue perfusion in patients undergoing liver surgery: A pilot randomised controlled trial.

Although fluid administration is a key strategy to optimise haemodynamic status and tissue perfusion, optimal fluid administration during liver surgery remains controversial. To test the hypothesis that a goal-directed fluid therapy (GDFT) strategy, when compared with a conventional fluid strategy, would better optimise systemic blood flow and lead to improved urethral tissue perfusion (a new variable to assess peripheral blood flow), without increasing blood loss. Single-centre prospective randomised controlled superiority study. Erasme Hospital. Patients undergoing liver surgery. Forty patients were randomised into two groups: all received a basal crystalloid infusion (maximum 2 ml kg-1 h-1). In the conventional fluid group, the goal was to maintain central venous pressure (CVP) as low as possible during the dissection phase by giving minimal additional fluid, while in the posttransection phase, anaesthetists were free to compensate for any presumed fluid deficit. In the GDFT group, patients received in addition to the basal infusion, multiple minifluid challenges of crystalloid to maintain stroke volume (SV) variation less than 13%. Noradrenaline infusion was titrated to keep mean arterial pressure more than 65 mmHg in all patients. The mean intra-operative urethral perfusion index. The mean urethral perfusion index was significantly higher in the GDFT group than in the conventional fluid group (8.70 [5.72 to 13.10] vs. 6.05 [4.95 to 8.75], P = 0.046). SV index (ml m-2) and cardiac index (l min-1 m-2) were higher in the GDFT group (48 ± 9 vs. 33 ± 7 and 3.5 ± 0.7 vs. 2.4 ± 0.4, respectively; P < 0.001). Although CVP was higher in the GDFT group (9.3 ± 2.5 vs. 6.5 ± 2.9 mmHg; P = 0.003), intra-operative blood loss was not significantly different in the two groups. In patients undergoing liver surgery, a GDFT strategy resulted in a higher mean urethral perfusion index than did a conventional fluid strategy and did not increase blood loss despite higher CVP. NCT04092608.

Comparison of pulse pressure variation, stroke volume variation, and plethysmographic variability index in pediatric patients undergoing craniotomy

Objective To compare well-known preload dynamic parameters intraoperatively including stroke volume variation (SVV), pulse pressure variation (PPV), and plethysmographic variability index (PVI) in children who underwent craniotomy for epileptogenic lesion excision. Methods A total of 30 children aged 0 to 14 years undergoing craniotomy for intracranial epileptogenic lesion excision were enrolled. During surgery, we measured PPV, SVV (measured by the Flotrac/Vigileo device), and PVI (measured by the Masimo Radical-7 monitor) simultaneously and continuously. Preload dynamic parameter measurements were collected at predefined steps: after induction of anesthesia, during opening the skull, intraoperative electroencephalogram monitoring, excision of epileptogenic lesion, skull closure, at the end of the operation. After exclusion of outliers, agreement among SVV, PPV, and PVI was assessed using repeated measures of Bland-Altman approach. The 4-quadrant and polar plot techniques were used to assess the trending ability among the changes in the three parameters. Results The mean SVV, PPV, and PVI were 8%±2%, 10%±3%, and 15%±7%, respectively during surgery. We analyzed a total of 834 paired measurements (3 to 8 data sets for each phase per patient). Repeated measures Bland-Altman analysis identified a bias of -2.3 and 95% confidence intervals between -1.9 and -2.7 (95% limits of agreement between -6.0 and 1.5) between PPV and SVV, showing significant correlation at all periods. The bias between PPV and PVI was -5.0 with 95% limits of agreement between -20.5 and 10.5, and that between SVV and PVI was -7.5 with 95% limits of agreement between -22.7 and 7.8, both not showing significant correlation. Reflected by 4-quadrant plots, the con-cordance rates showing the trending ability between the changes in PPV and SVV, PPV and PVI, SVV and PVI were 88.6%, 50.4%, and 50.1%, respectively. The concordance rate between PPV and SVV was higher (92.7%) in children aged less than 3 years compared with those aged 3 and more than 3 years. The mean angular bias, radial limits of agreement, and angular concordance rate in the polar analysis were not clinically acceptable in the changes between arterial pressure waveform-based parameters and volume-based PVI (PPV vs. PVI: angular mean bias 8.4°, angular concordance rate 29.9%; SVV vs. PVI: angular mean bias 2.4°, angular concordance rate 29.1%). There was a high concordance between the two arterial pressure waveform-based parameters reflected by the polar plot (angular mean bias -0.22°, angular concordance rate 86.6%). Conclusion PPV can be viewed as a surrogate for SVV, especially in children aged less than 3 years. The agreement between arterial pressure waveform-based preload parameters (PPV and SVV) and PVI is poor and these two should not be considered interchangeable. Attempt to combine PVI and PPV for improving the anesthesiologist's ability to monitor cardiac preload in major pediatric surgery is warranted.

Effect of Goal-directed Fluid Therapy on the Shedding of the Glycocalyx Layer in Retroperitoneal Tumour Resection.

To evaluate the effects of different stroke volume variation (SVV) targets on endothelial glycocalyx (EG) shedding. Randomised controlled trial. Department of Anaesthesiology, Peking University International Hospital, Beijing, China, from February to June 2018. Patients undergoing elective retroperitoneal tumour resection were assigned to one of two groups. SVV 9% group (n=40), who received a more traditional (liberal) fluid therapy with SVV ≤9%; and the SVV 14% group (n=40), received restrictive fluid therapy with SVV ≤14%. Patients' serum concentrations of syndecan-1 (SDC-1), interleukin-6 (IL-6) and tumour necrosis factor-α (TNF-α) were measured at the time that patients entered the operating theatre; at 1- and 4-hours following initiation of the surgery; and at 24- and 72-hours post-surgery. Postoperative complications, and one-year survival rates were also noted. Perioperative serum SDC-1, IL-6 and TNF-α concentrations were significantly elevated in both groups, which were more pronounced in SVV 9% (p = 0.028, <0.001, and <0.001 respectively). A positive correlation was observed between SDC-1 and TNF-α, L-6, and infusion volume, respectively. Postoperative complications, including fever and blood transfusion, were more aggravated in SVV 9% than those in SVV 14% (80% vs. 59%, and 45% vs. 23.1%, both p <0.05). However, no significant difference in the one-year survival rate was observed. Using SVV 14% as a target for guiding fluid therapy in elective retroperitoneal tumour resection was associated with reduced perioperative glycocalyx shedding, ameliorated inflammatory response, and reduced postoperative complications. Key Words: Randomised controlled trial, Retroperitoneal neoplasms, Glycocalyx, Tumour necrosis factor-alpha, Interleukin-6, Fluid therapy, Stroke volume.

Perioperative goal-directed therapy in high-risk abdominal surgery. A multicenter randomized controlled superiority trial

Study objectiveThe potential of perioperative goal-directed therapy (PGDT) to improve outcome after high-risk abdominal surgery remains subject of debate. In particular, there is a need for large, multicenter trials focusing on relevant patient outcomes to confirm the evidence found in small, single center studies including minor complications in their composite endpoints. The present study therefore aims to investigate the effect of an arterial waveform analysis based PGDT algorithm on the incidence of major complications including mortality after high-risk abdominal surgery. DesignProspective randomized controlled multicenter trial. SettingOperating theatres and Post-Anesthesia/Intensive Care units (PACU/ICU) of four tertiary hospitals in The Netherlands. PatientsA total number of 482 patients undergoing elective, abdominal surgery that is considered high-risk due to the extent of the procedure and/or patient comorbidities. InterventionsHemodynamic therapy using an age-specific PGDT algorithm including cardiac index (CI) and stroke volume variation (SVV) measurements during a 24-h perioperative period starting at induction of anesthesia. MeasurementsThe average number of major complications (including mortality) within 30 days after surgery, the number of minor complications, hospital and PACU/ICU length of stay (LOS), amounts of fluids and vasoactive medications used. Complications were graded using the Accordion severity grading system. ResultsThe average number of major complications per patient was 0.79 (PGDT group) versus 0.69 (control group) (p = 0.195). There were no statistically significant differences in the number of minor complications, hospital LOS, PACU/ICU LOS, or grading of complications. Patients in the PGDT group received more fluids intraoperatively, more dobutamine intra- and postoperatively, while patients in the control group received more phenylephrine during the operation. ConclusionsPGDT based on a CI and SVV driven algorithm did not result in improved outcomes after high-risk abdominal surgery. Clinical trial registrationNetherlands Trial Registry: NTR3380.

The effect of fluid bolus administration on cerebral tissue oxygenation in post-cardiac arrest patients

PurposeFluid boluses (FB) are often used in post-cardiac arrest (CA) patients with haemodynamic instability. Although FB may improve cardiac output (CO) and mean arterial pressure (MAP), FB may also increase central venous pressure (CVP), reduce arterial PaO2, dilute haemoglobin and cause interstitial oedema. The aim of the present study was to investigate the net effect of FB administration on cerebral tissue oxygenation saturation (SctO2) in post-CA patients. MethodsPre-planned sub-study of the Neuroprotect post-CA trial (NCT02541591). Patients with anticipated fluid responsiveness based on stroke volume variation (SVV) or passive leg raising test were administered a FB of 500 ml plasma-lyte A (Baxter Healthcare) and underwent pre- and post-FB assessments of stroke volume, CO, MAP, CVP, haemoglobin, PaO2 and SctO2. Results52 patients (mean age 64 ± 12 years, 75% male) received a total of 115 FB. Although administration of a FB resulted in a significant increase of stroke volume (63 ± 22 vs 67 ± 23 mL, p = 0.001), CO (4,2 ± 1,6 vs 4,4 ± 1,7 L/min, p = 0.001) and MAP (74,8 ± 13,2 vs 79,2 ± 12,9 mmHg, p = 0.004), it did not improve SctO2 (68.54 ± 6.99 vs 68.70 ± 6.80%, p = 0.49). Fluid bolus administration also resulted in a significant increase of CVP (10,0 ± 4,5 vs 10,7 ± 4,9 mmHg, p = 0.02), but did not affect PaO2 (99 ± 31 vs 94 ± 31 mmHg, p = 0.15) or haemoglobin concentrations (12,9 ± 2,1 vs 12,8 ± 2,2 g/dL, p = 0.10). In a multivariate model, FB-induced changes in CO (beta 0,77; p = 0.004) and in CVP (beta −0,23; p = 0.02) but not in MAP (beta 0,02; p = 0.18) predicted post-FB ΔSctO2. ConclusionsDespite improvements in CO and MAP, FB administration did not improve SctO2 in post-cardiac arrest patients.

Effect of different levels of stroke volume variation on the endothelial glycocalyx of patients undergoing colorectal surgery: A randomized clinical trial.

What is the central question of this study? Massive infusion can destroy the endothelial glycocalyx. We compared the serum concentrations of endothelial glycocalyx components and atrial natriuretic peptide and the outcomes of patients with different levels of stroke volume variation (SVV). What is the main finding and its importance? With a decrease in SVV, the serum concentrations of endothelial glycocalyx components and atrial natriuretic peptide increased, whereas the oxygenation index decreased. When the intraoperative SVV was maintained at 7-10%, the patients had better postoperative recovery and shorter postoperative hospital stays. Therefore, it is advisable to maintain the SVV between 7 and 10%. Dynamic haemodynamic parameters, such as stroke volume variation (SVV), can be used for blood volume monitoring. However, studies have determined the SVV threshold but not the optimal level. The endothelial glycocalyx (EG) plays an important role in maintaining vascular permeability. Moreover, rapid and massive infusion can lead to the degradation, shedding and destruction of the EG. We aimed to explore the effects of different SVV values (11-14, 7-10 or 3-6%) on the EG in 54 patients who were scheduled for elective colorectal tumour surgery and to identify the optimal peri-operative fluid therapy strategy. The concentrations of EG degradation products (heparin sulphate, hyaluronic acid and syndecan-1) and atrial natriuretic peptide were higher when the SVV was maintained between 3 and 6% after fluid therapy compared with pre-infusion (P<0.05). Comparison of postoperative complications and hospitalization time among the three SVV levels was not statistically significant (P>0.05). The postoperative hospitalization time in patients with SVV of 7-10% was shorter than that in patients with SVV of 3-6%. Infusion of a large volume of fluid, with increasing EG degeneration and atrial natriuretic peptide concentrations, might be related to postoperative outcomes.

Ability of short-time low peep challenge to predict fluid responsiveness in mechanically ventilated patients in the intensive care.

Short-time low PEEP challenge (SLPC, application of additional 5 cmH2O PEEP to patients for 30 s) is a novel functional hemodynamic test presented in the literature. We hypothesized that SLPC could predict fluid responsiveness better than stroke volume variation (SVV) in mechanically ventilated intensive care patients. Heart rate, mean arterial pressure, stroke volume index (SVI) and SVV were recorded before SLPC, during SLPC and before and after 500 mL fluid loading. Patients whose SVI increased more than 15% after the fluid loading were defined as fluid responders. Reciever operating characteristics (ROC) curves were generated to evaluate the abilities of the methods to predict fluid responsiveness. Fifty-five patients completed the study. Twenty-five (46%) of them were responders. Decrease percentage in SVI during SLPC (SVIΔ%–SLPC) was 11.6 ± 5.2% and 4.3 ± 2.2% in responders and non-responders, respectively (p < 0.001). A good correlation was found between SVIΔ%–SLPC and percentage change in SVI after fluid loading (r = 0.728, P < 0.001). Areas under the ROC curves (ROC–AUC) of SVIΔ%–SLPC and SVV were 0.951 (95% CI 0.857–0.991) and 0.747 (95% CI 0.611–0.854), respectively. The ROC–AUC of SVIΔ%–SLPC was significantly higher than that of SVV (p = 0.0045). The best cut-off value of SVIΔ%–SLPC was 7.5% with 90% sensitivity and 96% specificity. The percentage change in SVI during SLPC predicts fluid responsiveness in intensive care patients who are ventilated with low tidal volumes; the sensitivity and specificity values are higher than those of SVV.