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Background: The present trial was designed to assess whether individualized strategies of fluid administration using a noninvasive plethysmographic variability index could reduce the postoperative hospital length of stay and morbidity after intermediate-risk surgery., Methods: This was a multicenter, randomized, nonblinded parallel-group clinical trial conducted in five hospitals. Adult patients in sinus rhythm having elective orthopedic surgery (knee or hip arthroplasty) under general anesthesia were enrolled. Individualized hemodynamic management aimed to achieve a plethysmographic variability index under 13%, and the standard management strategy aimed to maintain a mean arterial pressure above 65 mmHg during general anesthesia. The primary outcome was the postoperative hospital length of stay decided by surgeons blinded to the group allocation of the patient., Results: In total, 447 patients were randomized, and 438 were included in the analysis. The mean hospital length of stay ± SD was 6 ± 3 days for the plethysmographic variability index group and 6 ± 3 days for the control group (adjusted difference, 0.0 days; 95% CI, -0.6 to 0.5; P = 0.860); the theoretical postoperative hospital length of stay was 4 ± 2 days for the plethysmographic variability index group and 4 ± 1 days for the control group (P = 0.238). In the plethysmographic variability index and control groups, serious postoperative cardiac complications occurred in 3 of 217 (1%) and 2 of 224 (1%) patients (P = 0.681), acute postoperative renal failure occurred in 9 (4%) and 8 (4%) patients (P = 0.808), the troponin Ic concentration was more than 0.06 μg/l within 5 days postoperatively for 6 (3%) and 5 (2%) patients (P = 0.768), and the postoperative arterial lactate measurements were 1.44 ± 1.01 and 1.43 ± 0.95 mmol/l (P = 0.974), respectively., Conclusions: Among intermediate-risk patients having orthopedic surgery with general anesthesia, fluid administration guided by the plethysmographic variability index did not shorten the duration of hospitalization or reduce complications.

Background: Intraoperative use of hydroxyethyl starch (HES) may increase the risk of postoperative acute kidney injury (AKI). Data from large populations are lacking. We aimed to assess whether intraoperative administration of 6% HES 130/0.4 is associated with AKI in non-cardiac surgery., Methods: This retrospective study used the electronic records concerning elective abdominal, urologic, thoracic and peripheral vascular surgeries from 2010 to 2015. HES and non-HES patients were compared using a propensity score matching. Postoperative AKI, defined by stage 3 of the Kidney Disease Improving Global Outcomes (KDIGO) score, was the primary outcome. Because the use of HES markedly decreased in 2013, additional analyses, restricted to the 2010-2012 period, were also performed., Results: In total, 23,045, and 11,691 patients were included in the whole, and restricted periods, respectively. The reduction in HES use was not accompanied by any change in the incidence of AKI. Unadjusted association between HES and KDIGO 3 AKI was significant (OR [95% CI] of 2.13 [1.67, 2.71]). For the whole period, 6460 patients were matched. Odd ratios for KDIGO 3 and all-stage AKI when using HES (10.3±4.7mL.kg -1 ) were 1.20 (95% CI [0.74, 1.95]), and 1.21 (95% CI [0.95, 1.54]), respectively. There was no association with the initiation of renal replacement therapy or in-hospital mortality either. Similar results were found for the restricted period., Conclusion: The intraoperative use of moderate doses of 6% HES 130/0.4 was not associated with increased risk of AKI. No conclusion can be drawn for higher doses of HES., (Copyright © 2020 Société française d'anesthésie et de réanimation (Sfar). Published by Elsevier Masson SAS. All rights reserved.)

Background: Dynamic indices, such as pulse pressure variation (PPV), are inaccurate predictors of fluid responsiveness in mechanically ventilated patients with low tidal volume. This study aimed to test whether changes in continuous cardiac index (CCI), PPV, and stroke volume variation (SVV) after a mini-fluid challenge (100 ml of fluid during 1 min) could predict fluid responsiveness in these patients., Methods: We prospectively studied 49 critically ill, deeply sedated, and mechanically ventilated patients (tidal volume <8 ml kg(-1) of ideal body weight) without cardiac arrhythmias, in whom a fluid challenge was indicated because of circulatory failure. The CCI, SVV (PiCCO™; Pulsion), and PPV (MP70™; Philips) were measured before and after 100 ml of colloid infusion during 1 min, and then after the additional infusion of 400 ml during 14 min. Responders were defined as subjects with a ≥15% increase in cardiac index (transpulmonary thermodilution) after the full (500 ml) fluid challenge. Areas under the receiver operating characteristic curves (AUCs) and the grey zones were determined for changes in CCI (ΔCCI100), SVV (ΔSVV100), and PPV (ΔPPV100) after 100 ml fluid challenge., Results: Twenty-two subjects were responders. The ΔCCI100 predicted fluid responsiveness with an AUC of 0.78. The grey zone was large and included 67% of subjects. The ΔSVV100 and ΔPPV100 predicted fluid responsiveness with AUCs of 0.91 and 0.92, respectively. Grey zones were small, including ≤12% of subjects for both indices., Conclusions: The ΔSVV100 and ΔPPV100 predict fluid responsiveness accurately and better than ΔCCI100 (PiCCO™; Pulsion) in patients with circulatory failure and ventilated with low volumes., (© The Author 2015. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Background: Respiratory arterial pulse pressure variations (PPV) are the best predictors of fluid responsiveness in mechanically ventilated patients during general anesthesia. However, previous studies were performed in a small number of patients and determined a single cutoff point to make clinical discrimination. The authors sought to test the predictive value of PPV in a large, multicenter study and to express it using a gray zone approach., Methods: The authors studied 413 patients during general anesthesia and mechanical ventilation in four centers. PPV, central venous pressure, and cardiac output were recorded before and after volume expansion (VE). Response to VE was defined as more than 15% increase in cardiac output after VE. The following approaches were used to determine the gray zones: resampled and two-graph receiver operator characteristic curves. The impact of changes in the benefit-risk balance of VE on the gray zone was also evaluated., Results: The authors observed 209 responders (51%) and 204 nonresponders (49%) to VE. The area under receiver operating characteristic curve was 0.89 (95% CI: 0.86-0.92) for PPV, compared with 0.57 (95% CI: 0.54-0.59) for central venous pressure (P < 10). The gray zone approach identified a range of PPV values (between 9% and 13%) for which fluid responsiveness could not be predicted reliably. These PPV values were seen in 98 (24%) patients. Changes in the cost ratio of VE moderately affected the gray zone limits., Conclusion: Despite a strong predictive value, PPV may be inconclusive (between 9% and 13%) in approximately 25% of patients during general anesthesia.

Dynamic variables of fluid responsiveness are useful guides for fluid management in patients under controlled positive pressure ventilation. In the previous issue of Critical Care, Jacques and colleagues show that these variables remain reliable predictors of fluid responsiveness in a porcine model of intra-abdominal hypertension, but threshold values are higher than during normal intra-abdominal pressure. Their threshold values, however, cannot be applied to clinical practice. This study suggests that intra-abdominal pressure must be measured in critically ill patients, and 'supranormal' values of dynamic variables should be analyzed with caution. The 'fluid responsive part' of an increased dynamic variable in such patients may be estimated by measuring its change during a fluid challenge.

Introduction: Dynamic predictors of fluid responsiveness have made automated management of fluid resuscitation more practical. We present initial simulation data for a novel closed-loop fluid-management algorithm (LIR, Learning Intravenous Resuscitator)., Methods: The performance of the closed-loop algorithm was tested in three phases by using a patient simulator including a pulse-pressure variation output. In the first phase, LIR was tested in three different hemorrhage scenarios and compared with no management. In the second phase, we compared LIR with 20 practicing anesthesiologists for the management of a simulated hemorrhage scenario. In the third phase, LIR was tested under conditions of noise and artifact in the dynamic predictor., Results: In the first phase, we observed a significant difference between the unmanaged and the LIR groups in moderate to large hemorrhages in heart rate (76 ± 8 versus 141 ± 29 beats/min), mean arterial pressure (91 ± 6 versus 59 ± 26 mm Hg), and cardiac output (CO; (6.4 ± 0.9 versus 3.2 ± 1.8 L/min) (P < 0.005 for all comparisons). In the second phase, LIR intervened significantly earlier than the practitioners (16.0 ± 1.3 minutes versus 21.5 ± 5.6 minutes; P < 0.05) and gave more total fluid (2,675 ± 244 ml versus 1,968 ± 644 ml; P < 0.05). The mean CO was higher in the LIR group than in the practitioner group (5.9 ± 0.2 versus 5.2 ± 0.6 L/min; P < 0.05). Finally, in the third phase, despite the addition of noise to the pulse-pressure variation value, no significant difference was found across conditions in mean, final, or minimum CO., Conclusion: These data demonstrate that LIR is an effective volumetric resuscitator in simulated hemorrhage scenarios and improved physician management of the simulated hemorrhages.

Background: The aim of this study was to evaluate potential predictors of fluid responsiveness obtained during major hepatic surgery. The predictors studied were invasive monitoring of intravascular pressures (radial and pulmonary artery catheter), including direct measurement of respiratory variation in arterial pulse pressure (PPVart), transoesophageal echocardiography (TOE), and non-invasive estimates of PPVart from the infrared photoplethysmography waveform from the Finapres (PPVfina) and the pulse oximetry waveform (PPVsat)., Methods: We conducted a prospective study of 54 fluid challenges (250 ml colloid) given for haemodynamic instability in eight patients undergoing hepatic resection. Fluid responsiveness was defined as an increase in stroke volume index (SVI) >or=10%. The following variables were recorded before each fluid challenge: right atrial pressure (RAP), pulmonary artery occlusion pressure (PAOP), PPVart, PPVfina, PPVsat, and the TOE-derived variables left ventricular end-diastolic area index (LVEDAI), early/late (E/A) diastolic filling wave ratio, deceleration time of the E wave (MDT) of mitral flow and the systolic fraction of the pulmonary venous flow (SF)., Results: Only PPVfina, PPVart (both P<0.001), PPVsat (P=0.02), LVEDAI and MDT (both P=0.04) were different in responder vs non-responder fluid challenges. The areas under the receiver operating characteristic (ROC) curves were 0.81 (PPVfina), 0.79 (PPVart), 0.70 (LVEDAI), 0.68 (PPVsat and MDT), 0.63 (RAP), 0.62 (E/A), 0.55 (PAOP) and 0.42 (SF). The areas under the ROC curves for RAP, E/A, PAOP and SF were significantly less than that for PPVfina (P<0.05 in each case). Only PPVart (r=0.59, P=0.0001) and PPVfina (r=0.56, P=0.0001) correlated with the fluid challenge-induced changes in SVI., Conclusions: PPVart and PPVfina predict fluid responsiveness during major hepatic surgery. This suggests that intraoperative monitoring of fluid responsiveness may be implemented simply and non-invasively.

Purpose: To date, no monitoring has proved its usefulness for both interpretation and treatment of arterial hypotension following pheochromocytoma resection. In this prospective observational study, we measured the negative component (Deltadown) of the respiratory systolic pressure variation in order to assess its ability to guide fluid therapy in 13 patients undergoing pheochromocytoma surgery., Methods: The arterial pressure waveform was recorded via a 20-g radial artery catheter. Deltadown was measured during abdominal exploration (baseline), after fluid loading, before and following tumour resection, and during treatment of arterial hypotension., Results: At baseline, Deltadown ranged between 1 and 15 mmHg (median: 3 mmHg). Volume loading (500 mL colloid over 20 min) performed during abdominal exploration significantly reduced Deltadown (P = 0.001) and resulted in Deltadown values

Background: Monitoring left ventricular preload is critical to achieve adequate fluid resuscitation in patients with hypotension and sepsis. This prospective study tested the correlation of the pulmonary artery occlusion pressure, the left ventricular end-diastolic area index measured by transesophageal echocardiography, the arterial systolic pressure variation (the difference between maximal and minimal systolic blood pressure values during one mechanical breath), and its delta down (dDown) component (= apneic - minimum systolic blood pressure) with the response of cardiac output to volume expansion during sepsis., Methods: Preload parameters were measured at baseline and during graded volume expansion (increments of 500 ml) in 15 patients with sepsis-induced hypotension who required mechanical ventilation. Each volume-loading step (VLS) was classified as a responder (increase in stroke volume index > or = 15%) or a nonresponder. Successive VLSs were performed until a nonresponder VLS was obtained., Results: Thirty-five VLSs (21 responders) were performed. Fluid loading caused an overall significant increase in pulmonary artery occlusion pressure and end-diastolic area index, and a significant decrease in systolic pressure variation and delta down (P < 0.01). There was a significant difference between responder and nonresponder VLSs in end-diastolic area index, systolic pressure variation, and dDown, but not in pulmonary artery occlusion pressure. Receiver-operator curve analysis showed that dDown was a more accurate indicator of the response of stroke volume index to volume loading than end-diastolic area index and pulmonary artery occlusion pressure. A dDown component of more than 5 mmHg indicated that the stroke volume index would increase in response to a subsequent fluid challenge (positive and negative predictive values: 95% and 93%, respectively)., Conclusion: The dDown component of the systolic pressure variation is a sensitive indicator of the response of cardiac output to volume infusion in patient with sepsis-induced hypotension who require mechanical ventilation.