Stroke Volume Variation Research Articles

Assessing volume responsiveness using right ventricular dynamic indicators of preload

PurposeDynamic indicators of preload currently only do reflect preload requirements of the left ventricle. To date, no dynamic indicators of right ventricular preload have been established. The aim of this study was to calculate dynamic indicators of right ventricular preload and assess their ability to predict ventricular volume responsiveness.Materials and methodsThe study was designed as experimental trial in 20 anaesthetized pigs. Micro-tip catheters and ultrasonic flow probes were used as experimental reference to enable measurement of right ventricular stroke volume and pulse pressure. Hypovolemia was induced (withdrawal of blood 20 ml/kg) and thereafter three volume-loading steps were performed. ROC analysis was performed to assess the ability of dynamic right ventricular parameters to predict volume response.ResultsROC analysis revealed an area under the curve (AUC) of 0.82 (CI 95% 0.73–0.89; p < 0.001) for right ventricular stroke volume variation (SVVRV), an AUC of 0.72 (CI 95% 0.53–0.85; p = 0.02) for pulmonary artery pulse pressure variation (PPVPA) and an AUC of 0.66 (CI 95% 0.51–0.79; p = 0.04) for pulmonary artery systolic pressure variation (SPVPA).ConclusionsIn our experimental animal setting, calculating dynamic indicators of right ventricular preload is possible and appears promising in predicting volume responsiveness.

The Effect of Intraoperative Fluid Management According to Stroke Volume Variation on Postoperative Bowel Function Recovery in Colorectal Cancer Surgery.

Stroke volume variation (SVV) has been used to predict fluid responsiveness; however, it remains unclear whether goal-directed fluid therapy using SVV contributes to bowel function recovery in abdominal surgery. This prospective randomized controlled trial aimed to compare bowel movement recovery in patients undergoing colon resection surgery between groups using traditional or SVV-based methods for intravenous fluid management. We collected data between March 2015 and July 2017. Bowel function recovery was analyzed based on the gas-passing time, sips of water time, and soft diet (SD) time. Finally, we analyzed data from 60 patients. There was no significant between-group difference in the patients’ characteristics. Compared with the control group (n = 30), the SVV group (n = 30) had a significantly higher colloid volume and lower crystalloid volume. Moreover, the gas-passing time (77.8 vs. 85.3 h, p = 0.034) and SD time (67.6 vs. 85.1 h, p < 0.001) were significantly faster in the SVV group than in the control group. Compared with the control group, the SVV group showed significantly lower scores of pain on a numeric rating scale and morphine equivalent doses during post-anesthetic care, at 24 postoperative hours, and at 48 postoperative hours. Our findings suggested that, compared with the control group, the SVV group showed a faster postoperative SD time, reduced acute postoperative pain intensity, and lower rescue analgesics. Therefore, SVV-based optimal fluid management is expected to potentially contribute to postoperative bowel function recovery in patients undergoing colon resection surgery.

Individualized positive end-expiratory pressure in patients undergoing thoracoscopic lobectomy: a randomized controlled trial

Background and objectivesWith the intensive study of lung protective ventilation strategies, people begin to advocate the individualized application of positive end-expiratory pressure (PEEP). This study investigated the optimal PEEP in patients during one-lung ventilation (OLV) and its effects on pulmonary mechanics and oxygenation. MethodsFifty-eight patients who underwent elective thoracoscopic lobectomy were randomly divided into two groups. Both groups received an alveolar recruitment maneuver (ARM) after OLV. Patients in Group A received optimal PEEP followed by PEEP decremental titration, while Group B received standard 5 cmH2O PEEP until the end of OLV. Relevant indexes of respiratory mechanics, pulmonary oxygenation and hemodynamics were recorded after entering the operating room (T0), 10 minutes after intubation (T1), pre-ARM (T2), 20 minutes after the application of optimal PEEP (T3), at the end of OLV (T4) and at the end of surgery (T5). Postoperative outcomes were also assessed. ResultsThe optimal PEEP obtained in Group A was 8.8 ± 2.4 cmH2O, which positively correlated with BMI and forced vital capacity (FVC). Group A had a higher CPAT than Group B at T3, T4, T5 (p < 0.05) and a smaller ΔP than Group B at T3, T4 (p < 0.01). At T4, PaO2 was significantly higher in Group A (p < 0.01). At T3, stroke volume variation was higher in Group A (p < 0.01). Postoperative outcomes did not differ between the two groups. ConclusionsOur findings suggest that the individualized PEEP can increase lung compliance, reduce driving pressure, and improve pulmonary oxygenation in patients undergoing thoracoscopic lobectomy, with little effect on hemodynamics.

Characterization of the Insular Role in Cardiac Function through Intracranial Electrical Stimulation of the Human Insula

The link between brain function and cardiovascular dynamics is an important issue yet to be elucidated completely. The insula is a neocortical brain area that is thought to have a cardiac chronotropic regulatory function, but its role in cardiac contractility is unknown. We aimed to analyze the variability in heart rate and cardiac contractility after functional activation of different insular regions through direct electrical stimulation (E-stim) in humans. This was an observational, prospective study, including patients admitted for stereo-electroencephalographic recording because of refractory epilepsy, in whom the insular cortex was implanted. Patients with anatomical or electrophysiological insular abnormalities and those in whom E-stim produced subjective symptoms were excluded. Variations in heart rate (HR), stroke volume (SV), and cardiac output (CO) were analyzed during insular E-stim and compared with control E-stim of non-eloquent brain regions and sham stimulations. Ten patients were included, 5 implanted in the right insula (52 E-stim) and 5 in the left (37 E-stim). Demographic and clinical characteristics of both groups were similar. E-stim of both right and left insulas induced a significant decrease of the CO and HR, and an increase of the SV. E-stim of control electrodes and sham stimulations were not associated with variations in cardiac function. Blood pressure and respiratory rate remained unaltered. Our results suggest a direct chronotropic and inotropic cardiac depressor function of the right and left insulas. The evidence of an insular direct cardiac regulatory function might open a path in the prevention or treatment of heart failure, arrhythmias, and sudden unexpected death in epilepsy. ANN NEUROL 2021;89:1172-1180.

Collapsibility of caval vessels and right ventricular afterload: decoupling of stroke volume variation from preload during mechanical ventilation.

Collapsibility of caval vessels and stroke volume and pulse pressure variations (SVV, PPV) are used as indicators of volume responsiveness. Their behavior under increasing airway pressures and changing right ventricular afterload is incompletely understood. If the phenomena of SVV and PPV augmentation are manifestations of decreasing preload, they should be accompanied by decreasing transmural right atrial pressures. Eight healthy pigs equipped with ultrasonic flow probes on the pulmonary artery were exposed to positive end-expiratory pressure of 5 and 10 cmH2O and three volume states (Euvolemia, defined as SVV < 10%, Bleeding, and Retransfusion). SVV and PPV were calculated for the right and PPV for the left side of the circulation at increasing inspiratory airway pressures (15, 20, and 25 cmH2O). Right ventricular afterload was assessed by surrogate flow profile parameters. Transmural pressures in the right atrium and the inferior and superior caval vessels (IVC and SVC) were determined. Increasing airway pressure led to increases in ultrasonic surrogate parameters of right ventricular afterload, increasing transmural pressures in the right atrium and SVC, and a drop in transmural IVC pressure. SVV and PPV increased with increasing airway pressure, despite the increase in right atrial transmural pressure. Right ventricular stroke volume variation correlated with indicators of right ventricular afterload. This behavior was observed in both PEEP levels and all volume states. Stroke volume variation may reflect changes in right ventricular afterload rather than changes in preload.NEW & NOTEWORTHY Stroke volume variation and pulse pressure variation are used as indicators of preload or volume responsiveness of the heart. Our study shows that these variations are influenced by changes in right ventricular afterload and may therefore reflect right ventricular failure rather than pure volume responsiveness. A zone of collapse detaches the superior vena cava and its diameter variation from the right atrium.

A pilot study of short-term hemodynamic effects of negative pressure ventilation in chronic obstructive pulmonary disease assessed using electrical cardiometry.

BackgroundPulmonary rehabilitation combined with negative pressure ventilation (NPV) demonstrated benefits in patients with chronic obstructive pulmonary disease (COPD). The effect of NPV remains unknown. This study aims to clarify the short‐term response of the hemodynamic outcome of NPV in patients with COPD undergoing pulmonary rehabilitation program by electrical cardiometry.MethodsThis is an observational retrospective study of COPD patients who had been treated in a pulmonary rehabilitation unit with NPV between January 2018 and December 2019 that were enrolled to analyze the hemodynamic outcomes.ResultsThirty patients with COPD that were undergoing a pulmonary rehabilitation program and were regularly receiving NPV were enrolled. Cardiac output (p < .001) and heart rate (p < .001) showed a significant decrease after NPV. Stroke volume did not demonstrate significant change (p = .15). There was a significant decrease in thoracic fluid content (p = .016) and a significant increase in stroke volume variation (p = .038) systemic vascular resistance (p < .001) and left ventricular ejection time (p < .001). Other hemodynamic parameters were all comparable before and after NPV.ConclusionsNegative pressure ventilation demonstrated an impact on hemodynamics in patients with chronic obstructive pulmonary disease undergoing pulmonary rehabilitation. Electrical cardiometry is a feasible method of determining the hemodynamic effects of negative pressure ventilation. Thoracic fluid content significantly decreased immediately after the NPV.

Impact of goal-directed hemodynamic management on the incidence of acute kidney injury in patients undergoing partial nephrectomy: a pilot randomized controlled trial

BackgroundThe incidence of acute kidney injury (AKI) remains high after partial nephrectomy. Ischemia-reperfusion injury produced by renal hilum clamping during surgery might have contributed to the development of AKI. In this study we tested the hypothesis that goal-directed fluid and blood pressure management may reduce AKI in patients following partial nephrectomy.MethodsThis was a pilot randomized controlled trial. Adult patients who were scheduled to undergo partial nephrectomy were randomized into two groups. In the intervention group, goal-directed hemodynamic management was performed from renal hilum clamping until end of surgery; the target was to maintain stroke volume variation < 6%, cardiac index 3.0–4.0 L/min/m2 and mean arterial pressure > 95 mmHg with crystalloid fluids and infusion of dobutamine and/or norepinephrine. In the control group, hemodynamic management was performed according to routine practice. The primary outcome was the incidence of AKI within the first 3 postoperative days.ResultsFrom June 2016 to January 2017, 144 patients were enrolled and randomized (intervention group, n = 72; control group, n = 72). AKI developed in 12.5% of patients in the intervention group and in 20.8% of patients in the control group; the relative reduction of AKI was 39.9% in the intervention group but the difference was not statistically significant (relative risk 0.60, 95% confidence interval [CI] 0.28–1.28; P = 0.180). No significant differences were found regarding AKI classification, change of estimated glomerular filtration rate over time, incidence of postoperative 30-day complications, postoperative length of hospital stay, as well as 30-day and 6-month mortality between the two groups.ConclusionFor patients undergoing partial nephrectomy, goal-directed circulatory management during surgery reduced postoperative AKI by about 40%, although not significantly so. The trial was underpowered. Large sample size randomized trials are needed to confirm our results.Trial registrationClinicaltrials.gov identifier: NCT02803372. Date of registration: June 6, 2016.

Effect of fluid strategy on stroke volume, cardiac output, and fluid responsiveness in adult patients undergoing major abdominal surgery: a sub-study of the Restrictive versus Liberal Fluid Therapy in Major Abdominal Surgery (RELIEF) trial

BackgroundWe designed a prospective sub-study of the larger Restrictive versus Liberal Fluid Therapy in Major Abdominal Surgery (RELIEF) trial to measure differences in stroke volume and other haemodynamic parameters at the end of the intraoperative fluid protocols. The haemodynamic effects of the two fluid regimens may increase our understanding of the observed perioperative outcomes. MethodsStroke volume and cardiac output were measured with both an oesophageal Doppler ultrasound monitor and arterial pressure waveform analysis. Stroke volume variation, pulse pressure variation, and plethysmographic variability index were also obtained. A passive leg raise manoeuvre was performed to identify fluid responsiveness. ResultsAnalysis of 105 patients showed that the primary outcome, Doppler monitor-derived stroke volume index, was higher in the liberal group: restrictive 38.5 (28.6–48.8) vs liberal 44.0 (34.9–61.9) ml m−2; P=0.043. Similarly, there was a higher cardiac index in the liberal group: 2.96 (2.32–4.05) vs 2.42 (1.94–3.26) L min−1 m−2; P=0.015. Arterial-pressure-based stroke volume and cardiac index did not differ, nor was there a significant difference in stroke volume variation, pulse pressure variation, or plethysmographic variability index. The passive leg raise manoeuvre showed fluid responsiveness in 40% of restrictive and 30% of liberal protocol patients (not significant). ConclusionsThe liberal fluid group from the RELIEF trial had significantly higher Doppler ultrasound monitor-derived stroke volume and cardiac output compared with the restrictive fluid group at the end of the intraoperative period. Measures of fluid responsiveness did not differ significantly between groups. Clinical trial registrationACTRN12615000125527.

Intraoperative Assessment of Fluid Responsiveness in Normotensive Dogs under Isoflurane Anaesthesia.

The aim of this study was to evaluate the incidence of fluid responsiveness (FR) to a fluid challenge (FC) in normotensive dogs under anaesthesia. The accuracy of pulse pressure variation (PPV), systolic pressure variation (SPV), stroke volume variation (SVV), and plethysmographic variability index (PVI) for predicting FR was also evaluated. Dogs were anaesthetised with methadone, propofol, and inhaled isoflurane in oxygen, under volume-controlled mechanical ventilation. FC was performed by the administration of 5 mL/kg of Ringer’s lactate within 5 min. Cardiac index (CI; L/min/m2), PPV, (%), SVV (%), SPV (%), and PVI (%) were registered before and after FC. Data were analysed with ANOVA and ROC tests (p < 0.05). Fluid responsiveness was defined as 15% increase in CI. Eighty dogs completed the study. Fifty (62.5%) were responders and 30 (37.5%) were nonresponders. The PPV, PVI, SPV, and SVV cut-off values (AUC, p) for discriminating responders from nonresponders were PPV >13.8% (0.979, <0.001), PVI >14% (0.956, <0.001), SPV >4.1% (0.793, <0.001), and SVV >14.7% (0.729, <0.001), respectively. Up to 62.5% of normotensive dogs under inhalant anaesthesia may be fluid responders. PPV and PVI have better diagnostic accuracy to predict FR, compared to SPV and SVV.

Goal-directed Therapy and Postcystectomy Ileus: Comment.

We read with interest the recently published study by Arslan-Carlon et al. in Anesthesiology.1 This primary objective of this randomized, controlled trial (N = 283) was to determine whether a goal-directed fluid therapy approach would result in a lower incidence of postoperative ileus compared with a standard fluid therapy approach in patients undergoing open radical cystectomy. All patients had an arterial line coupled to an advanced hemodynamic monitoring device (EV-1000, Edwards Lifesciences, USA) to monitor advanced hemodynamic variables before, during, and immediately after surgery. No statistically significant difference in this primary outcome was found between the two groups. Interestingly, however, the authors identified a relative negative impact of goal-directed fluid therapy on acute kidney injury (AKI) incidence (secondary outcome) with more patients in the goal-directed fluid therapy group who experienced AKI (56% vs. 40%, P = 0.005). We do appreciate the statistical insignificance noted after taking into account Bonferroni adjustments (P = 0.170) because this is rarely done. We congratulate the authors for having performed such a rigorous study. We have, however, two main comments for any interested readers.First, although many clinicians throughout the world may use a similar hemodynamic algorithm that calls for fluid, vasopressor, or inotrope administration if stroke volume variation is greater than 12%, mean arterial pressure (MAP) less than 60 mmHg, or cardiac index less than 2.5 l · min–1 · m–2, there have been at least two large randomized, controlled trials demonstrating that targeting a higher arterial pressure during surgery is associated with less postoperative AKI. The first, from Futier et al.,2 reported a lower incidence of organ dysfunction in the group of patients with a targeted systolic arterial pressure closer to the patient’s baseline value compared with the control group. The second, from Wu et al.,3 demonstrated that targeting a MAP level between 80 and 95 mmHg in chronically hypertensive patients reduces postoperative AKI compared with two other MAP levels (65 to 79 and 96 to 110 mmHg). Additionally, French national guidelines recommend maintenance of a MAP target greater than 70 mmHg to prevent AKI in patients with chronic hypertension (which is the case in more than 60% of the current study population).4 As a result, the MAP level targeted in the current hemodynamic algorithm may have been too low and could be responsible for the higher incidence of AKI.Second, because both groups were monitored with an advanced hemodynamic monitor, we would have greatly appreciated summaries of advanced hemodynamic variables to better understand the results. It would be useful if the authors could provide mean MAP, stroke volume, cardiac index, and stroke volume variation during the case and also the percentage of procedure time the patients were hypotensive as defined using their algorithm of MAP less than 60 mmHg and the percentage of procedure time with a stroke volume variation greater than 12%. It is quite evident that clinicians’ compliance with the application of hemodynamic protocols remains poor, ranging between 62% and 87%, even within ideal study conditions.5,6 Compliance of less than 50% to protocols is reported in daily practice across different medical specialties, but at least 80% adherence is required to observe improved clinical outcomes.7–9 As a result, having hemodynamic data would allow readers to assess protocol compliance and determine whether advanced hemodynamic variables were well optimized throughout the perioperative period.Dr. Joosten has been a consultant for Edwards Lifesciences (Irvine, California), Aguettant Laboratoire (Lyon, France), and Fresenius Kabi GmbH (Bad Homburg, Germany). Dr. Legrand has received consulting fees from Novartis (Bale, Switzerland), lecture fees from Baxter (Lessines, Belgium) and Fresenius Kabi GmbH, and research support from Sphingotec (Hennigsdorf, Germany). The other authors declare no competing interests.

Pulse Pressure Variation is a Valuable Marker for Predicting Fluid Responsiveness in Brain-Dead Donors

PurposeHemodynamic management in brain-dead donors (BDDs) is challenging due to hemodynamic instabilities. We compared functional parameters with traditional parameters for hemodynamic monitoring in BDDs. Materials and methodsSeventeen BDDs with a positive balance of >500 mL for 8 hours were included. Functional hemodynamic monitoring, including pulse pressure variation (PPV), stroke volume variation (SVV), cardiac output, and systemic vascular resistance index (SVRI) was performed in the setting of tidal volume of 6 mL/kg to 8 mL/kg and minimal positive end-expiratory pressure of 5 cm to 8 cm H2O. Responders were defined by a cardiac output increase of >15% after fluid therapy. ResultsAmong the 17 BDDs (mean age, 46.80±13.91 years), 15 were male. Seven responders out of 17 (41.1%) had a significantly higher PPV (22.8±8.4 vs 13.4±5.9%, P = .038) and serum albumin level (3.2±0.6 vs 2.6±0.5 g/L, P = .040) at baseline than nonresponders. However, other hemodynamic markers such as SVV and SVRI were similar between groups. Traditional markers of volume status, such as heart rate, central venous pressure, hemoglobin, and serum uric acid level were also similar between the 2 groups. Hemodynamic markers including PPV, SVV, and SVRI were significantly reduced in responders. ConclusionsPPV was the most valuable hemodynamic marker for predicting volume responsiveness in BDDs.

Echocardiographic measure of dynamic arterial elastance predict pressure response during norepinephrine weaning: an observational study

The purpose of this study was to determine whether dynamic elastance EAdyn derived from echocardiographic measurements of stroke volume variations can predict the success of a one-step decrease of norepinephrine dose. In this prospective single-center study, 39 patients with vasoplegic syndrome treated with norepinephrine and for whom the attending physician had decided to decrease norepinephrine dose and monitored by thermodilution were analyzed. EAdyn is the ratio of pulse pressure variation to stroke volume variation and was calculated from echocardiography stroke volume variations and from transpulmonary thermodilution. Pulse pressure variation was obtained from invasive arterial monitoring. Responders were defined by a decrease in mean arterial pressure (MAP) > 10% following norepinephrine decrease. The median decrease in norepinephrine was of 0.04 [0.03–0.05] µg kg−1 min−1. Twelve patients (31%) were classified as pressure responders with a median decrease in MAP of 13% [12–15%]. EAdyn was lower in pressure responders (0.40 [0.24–0.57] vs 0.95 [0.77–1.09], p < 0.01). EAdyn was able to discriminate between pressure responders and non-responders with an area under the curve of 0.86 (CI95% [0.71 to1.0], p < 0.05). The optimal cut-off was 0.8. EAdyn calculated from the echocardiographic estimation of the stroke volume variation and the invasive arterial pulse pressure variation can be used to discriminate pressure response to norepinephrine weaning. Agreement between EAdyn calculated from echocardiography and thermodilution was poor. Echocardiographic EAdyn might be used at bedside to optimize hemodynamic treatment.

278 Assessing effects of lateral tilt on cardiac output using a Non-invasive technique

Aortocaval compression (ACC), or supine hypotension syndrome, may lead to adverse fetal outcomes secondary to changes in maternal hemodynamics. Lateral tilt has been advocated to address ACC. We aim to determine the maternal position with the least effect on maternal hemodynamics. Term pregnant women scheduled for induction of labor were first placed in semi-recumbent (baseline), followed by supine, 15o and 30 o left lateral tilt (LLT), each for 20 minutes period, after which hemodynamic parameters were measuring using non-invasive cardiac output monitor NICOM. Friedman ANOVA with Dunn’s test multiple comparison test were used for analysis. P<0.05 was considered statistically significant. Forty subjects were included (Table). Cardiac index (CI) significantly increased in the supine position compared with baseline (median [range]: 3.8 [2.8-5.2] vs 4.2 [2.9-5.9] L/min/m2). CI also increased in 15o and 30 o left lateral tilt but did not reach statistical significance (Figure). Compared with baseline, stroke volume index (SVI) significantly increased (baseline: 43.7 [31.0-65.0]; supine: 49.5 [34.0-77.0]; 15o LLT: 49.8 [34.0-70.0] and 30o LLT: 49.9 [32.0-66.0] ml/m2; P<0.05 for all; Figure) while maternal heart rate significantly decreased in all 3 positions (baseline: 88 [70-106], supine: 85[63-99], 15o LLT: 81 [61-98] and 30o LLT: 80.0 [61-96] bpm; P<0.05 for all). Stroke volume variation (SVV) significantly decreased in all 3 positions (baseline: 12.9 [8.0-18.0], supine: 11.6 [7.0-17.0], 15o LLT: 11.6 [6.0-20.0] and 30o LLT 11.5 [7.0-20.0] %; P<0.05 for all). Subgroup analysis for BMI above or below 30 Kg/m2 showed similar results. Compared to semi-recumbent position, supine followed by left tilt position led to improvements in maternal hemodynamic parameters. The improvement in SVV, a measure of hypovolemia, indicates an increase in venous return and upper-right shift in the Frank-Starling curve. It is best to avoid semi-recumbent position in term pregnancies.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

A Multicenter, Open-Label, Randomized Controlled Trial of a Conservative Fluid Management Strategy Compared With Usual Care in Participants After Cardiac Surgery: The Fluids After Bypass Study.

There is little evidence to guide fluid administration to patients admitted to the ICU following cardiac surgery. This study aimed to determine if a protocolized strategy known to reduce fluid administration when compared with usual care reduced ICU length of stay following cardiac surgery. Prospective, multicenter, parallel-group, randomized clinical trial. Five cardiac surgical centers in New Zealand conducted from November 2016 to December 2018 with final follow-up completed in July 2019. Seven-hundred fifteen patients undergoing cardiac surgery; 358 intervention and 357 usual care. Randomization to protocol-guided strategy utilizing stroke volume variation to guide administration of bolus fluid or usual care fluid administration until desedation or up to 24 hours. Primary outcome was length of stay in ICU. Organ dysfunction, mortality, process of care measures, patient-reported quality of life, and disability-free survival were collected up to day 180. Overall 666 of 715 (93.1%) received at least one fluid bolus. Patients in the intervention group received less bolus fluid (median [interquartile range], 1,000 mL [250-2,000 mL] vs 1,500 mL [500-2,500 mL]; p < 0.0001) and had a lower overall fluid balance (median [interquartile range], 319 mL [-284 to 1,274 mL] vs 673 mL [38-1,641 mL]; p < 0.0001) in the intervention period. There was no difference in ICU length of stay between the two groups (27.9 hr [21.8-53.5 hr] vs 25.6 hr [21.9-64.6 hr]; p = 0.95). There were no differences seen in development of organ dysfunction, quality of life, or disability-free survival at any time points. Hospital mortality was higher in the intervention group (4% vs 1.4%; p = 0.04). A protocol-guided strategy utilizing stroke volume variation to guide administration of bolus fluid when compared with usual care until desedation or up to 24 hours reduced the amount of fluid administered but did not reduce the length of stay in ICU.

Hemodynamic Changes via the Lung Recruitment Maneuver Can Predict Fluid Responsiveness in Stroke Volume and Arterial Pressure During One-Lung Ventilation.

We aimed to evaluate the ability of lung recruitment maneuver-induced hemodynamic changes to predict fluid responsiveness in patients undergoing lung-protective ventilation during one-lung ventilation (OLV). Thirty patients undergoing thoracic surgery with OLV (tidal volume: 6 mL/kg of ideal body weight and positive end-expiratory pressure: 5 cm H2O) were enrolled. The study protocol began 30 minutes after starting OLV. Simultaneous recordings were performed for hemodynamic variables of heart rate, mean arterial pressure (MAP), stroke volume (SV), pulse pressure variation (PPV), and stroke volume variation (SVV) were recorded at 4 time points: before recruitment maneuver (continuous airway pressure: 30 cm H2O for 30 seconds), at the end of recruitment maneuver, and before and after volume loading (250 mL over 10 minutes). Patients were recognized as fluid responders if the increase in SV or MAP was >10%. Receiver operating characteristic curves for percent decrease in SV and MAP by recruitment maneuver (ΔSVRM and ΔMAPRM, respectively) were generated to evaluate the ability to discriminate fluid responders from nonresponders. The gray-zone approach was applied for ΔSVRM and ΔMAPRM. Of 30 patients, there were 17 SV-responders (57%) and 12 blood pressure (BP)-responders (40%). Area under the curve (AUC) for ΔSVRM to discriminate SV-responders from nonresponders was 0.84 (95% confidence interval [CI], 0.67-0.95; P < .001). The best threshold for ΔSVRM to discriminate the SV-responders was -23.7% (95% CI, -41.2 to -17.8; sensitivity, 76.5% [95% CI, 50.1-93.2]; specificity, 84.6% [95% CI, 54.6-98.1]). For BP-responders, AUC for ΔMAPRM was 0.80 (95% CI, 0.61-0.92, P < .001). The best threshold for ΔMAPRM was -17.3% (95% CI, -23.9 to -5.1; sensitivity, 75.0% [95% CI, 42.8-94.5]; specificity, 77.8% [95% CI, 52.4-93.6]). With the gray-zone approach, the inconclusive range of ΔSVRM for SV-responders was -40.1% to -13.8% including 13 (43%) patients, and that of ΔMAPRM was -23.9% to -5.1%, which included 16 (53%) patients. ΔSVRM and ΔMAPRM could predict hemodynamic responses after volume expansion during OLV.

Comparison of the Efficacy of Different Arterial Waveform-derived Variables (Pulse Pressure Variation, Stroke Volume Variation, Systolic Pressure Variation) for Fluid Responsiveness in Hemodynamically Unstable Mechanically Ventilated Critically Ill Patients.

IntroductionThis study was conducted to assess fluid responsiveness in critically ill patients to avoid various complications of fluid overload.Material and methodsThis 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.ResultsIn 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.ConclusionWe 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.How to cite this articleKumar N, Malviya D, Nath SS, Rastogi S, Upadhyay V. Comparison of the Efficacy of Different Arterial Waveform-derived Variables (Pulse Pressure Variation, Stroke Volume Variation, Systolic Pressure Variation) for Fluid Responsiveness in Hemodynamically Unstable Mechanically Ventilated Critically Ill Patients. Indian J Crit Care Med 2021;25(1):48–53.

Dynamic arterial elastance measured with pressure recording analytical method, and mean arterial pressure responsiveness in hypotensive preload dependent patients undergoing cardiac surgery: A prospective cohort study.

Organ perfusion is a factor of cardiac output and perfusion pressure. Recent evidence shows that dynamic arterial elastance is a reliable index of the interaction between the left ventricle and the arterial system and, in turn, of left ventricular mechanical efficiency. A practical approach to the assessment of dynamic arterial elastance at the bedside is the ratio between pulse pressure variation and stroke volume variation, which might predict the effect of a fluid challenge on the arterial pressure in patients undergoing cardiac surgery. To evaluate the ability of dynamic arterial elastance, measured by the pressure recording analytical method (PRAM), to predict the response of mean arterial pressure (MAP) to a fluid challenge. Prospective observational study. Cardiac surgery patients in a university hospital. Preload-dependent (pulse pressure variation ≥13%), hypotensive (MAP ≤65 mmHg) patients, without right ventricular dysfunction, at the end of cardiac surgery. A 250 ml fluid challenge infused over 3 min. A receiver-operating characteristic curve was generated to test the ability of the baseline (before fluid challenge) dynamic arterial elastance (primary endpoint) and all other haemodynamic variables (secondary endpoint) to predict MAP responsiveness (≥10% increase in MAP) after a fluid challenge. Of 270 patients undergoing cardiac surgery, 97 (35.9%) were preload-dependent, hypotensive and received a fluid challenge. Of these 97 patients, 50 (51%) were MAP responders (≥10% increase in MAP) and 47 (48%) were MAP nonresponders (<10% increase in MAP). Baseline dynamic arterial elastance (mean ± SD) had an area under the curve of 0.64 ± 0.06 [95% confidence interval (CI), 0.53 to 0.73; P = 0.017]. A dynamic arterial elastance at least 1.07 with a grey zone ranging between 0.9 and 1.5 had 86% sensitivity (95% CI, 73 to 94) and 45% specificity (95% CI, 30 to 60) in predicting MAP increase. In a hypotensive preload-dependent cardiac surgery cohort without right ventricular dysfunction, dynamic arterial elastance measured by PRAM can predict pressure response for values greater than 1.5 or less than 0.9.

A comparative study of pulse pressure variation, stroke volume variation and central venous pressure in patients undergoing kidney transplantation.

Optimal intraoperative fluid management guided by central venous pressure (CVP), a traditional intravascular volume status indicator, has improved transplanted graft function during kidney transplantation (KT). Pulse pressure variation (PPV) and stroke volume variation (SVV) - dynamic preload indexes - are robust predictors of fluid responsiveness. This study aimed to compare the accuracy of PPV and CVP against SVV in predicting fluid responsiveness in terms of cost-effectiveness after a standardised empiric volume challenge in KT patients. 36 patients undergoing living-donor KT were analysed. PPV, SVV, CVP and cardiac index (CI) were measured before and after fluid loading with a hydroxyethyl starch solution (7 mL/kg of ideal body weight). Patients were classified as responders (n = 12) or non-responders (n = 24) to fluid loading when CI increases were ≥10% or <10%, respectively. The ability of PPV, SVV and CVP to predict fluid responsiveness was assessed using receiver operating characteristic (ROC) curves. SVV and CVP measured before fluid loading were correlated with changes in CI caused by fluid expansion (ρ = 0.33, P = 0.049 and ρ = -0.37, P = 0.026) in contrast to PPV (ρ = 0.14, P = 0.429). The ROC analysis showed that SVV and CVP predicted response to volume loading (area under the ROC curve = 0.781 and 0.727, respectively; P < 0.05). Under the conditions of our study, SVV and CVP exhibited similar performance in predicting fluid responsiveness and could inform fluid management during KT as compared with PPV.

Goal Directed Fluid Therapy based on Stroke Volume Variation and Oxygen Delivery Index using Electrical Cardiometry in patients undergoing Scoliosis Surgery

ABSTRACT Background: The primary outcome was to evaluate whether goal-directed fluid therapy (GDFT) protocol, established on stroke volume variation (SVV) and oxygen delivery index (DO2I) using electrical cardiometry (EC) monitor, would be effective in reducing perioperative packed red blood cells (RBCs) transfusion, whereas the secondary outcome was to compare the effects of GDFT with liberal fluid therapy (LFT) as regards total amount of fluids transfused, perioperative complications, and postoperative length of ICU and total hospital stay. Settings and Design: This study was a prospective randomized controlled clinical trial. Methods: The study was carried out on 48 patients scheduled for scoliosis surgery. Twenty-four patients, whose intraoperative fluid administration was managed with the GDFT protocol, were compared with 24 patients who received a liberal intraoperative fluid therapy. The proposal and raw data were registered on PACTR as PACTR202007901764021. Results: Patients in group II received less units of packed RBCs (P < 0.001) and a lower volume of intraoperative crystalloids (P < 0.001). They had significantly lower serum lactate levels 2 h after induction (P = 0.033), at the end of surgery (P = 0.001) and 2 h postoperatively (P < 0.001) with shorter ICU stay (P < 0.001), total hospital length of stay (P < 0.001), and faster return of bowel function (P = 0.005). Conclusion:: Application of a GDFT protocol, established o SVV and DO2I using EC monitor in patients undergoing scoliosis surgery, can lead to reduced packed RBCs transfusions, reduced total crystalloid volume infusions, less postoperative pulmonary complications, shorter ICU, and total hospital stay with faster return of gastrointestinal function. Abbreviations: GDFT: goal-directed fluid therapy; SVV: stroke volume variation; DO2I: oxygen delivery index; EC: electrical cardiometry; LFT: liberal fluid therapy; CI: cardiac index; RBCs: red blood cells; CO: cardiac output; IVC: inferior vena cava; CVP: central venous pressure; MAP: mean arterial pressure; CaO2: arterial oxygen content; UOP: urine output; ASA: American Society of Anesthesiologist; BMI: body mass index; ROC: receiver operating characteristic; AUC: area under the curve; FFP: fresh frozen plasma

The influence of positive end-expiratory pressure (PEEP) in predicting fluid responsiveness in patients undergoing one-lung ventilation.

Background: Dynamic preload parameters such as pulse pressure variation (PPV) and stroke volume variation (SVV) have widely been used as accurate predictors for fluid responsiveness in patients under mechanical ventilation. To circumvent the limitation of decreased cyclic change of intrathoracic pressure, we performed an intermittent PEEP challenge test to evaluate whether PPV or SVV can predict fluid responsiveness during one-lung ventilation (OLV).Methods: Forty patients undergoing OLV were analyzed. Baseline hemodynamic variables including PPV and SVV and respiratory variables were recorded after chest opening in lateral position under OLV (T1). Five minutes after application of PEEP 10 cmH2O, the parameters were recorded (T2). Thereafter, PEEP was withdrawn to 0 cmH2O for 5 minutes (T3), and fluid loading was performed with balanced crystalloid solution 6 mL/kg of ideal body weight for 5 minutes. Five minutes after completion of fluid loading, all variables were recorded (T4). The patient was classified as fluid responder if SV increased ≥10% after fluid loading and as non-responder if SV increased <10%.Results: Prediction of fluid responsiveness was evaluated with area under the receiver operating characteristic (ROC) curve (AUC). Change in stroke volume variation (ΔSVV) showed AUC of 0.9 (P < 0.001), 95% CI = 0.82-0.99, sensitivity = 88%, specificity = 82% for discrimination of fluid responsiveness. Change in pulse pressure variation (ΔPPV) showed AUC of 0.88 (P < 0.001), 95% CI = 0.78-0.97, sensitivity = 83%, specificity = 72% in predictability of fluid responsiveness. Cardiac index and stroke volume were well maintained after PEEP challenge in non-responders while they increased in responders.Conclusions: ΔPPV and ΔSVV induced by PEEP challenge are reliable parameters to predict fluid responsiveness as well as very good predictors of fluid unresponsiveness during OLV.