Fluid responsiveness prediction using Vigileo FloTrac measured cardiac output changes during passive leg raise test

Internal jugular vein collapsibility does not predict fluid responsiveness in spontaneously breathing patients after cardiac surgery

PURPOSE

The objective of our study was to evaluate the diagnostic accuracy of internal jugular vein (IJV) collapsibility as a predictor of fluid responsiveness in spontaneously breathing patients after cardiac surgery.

METHODS

In this prospective observational study, spontaneously breathing patients were enrolled on the first postoperative day after coronary artery bypass grafting. Hemodynamic data coupled with simultaneous ultrasound assessment of the IJV were collected at baseline and after passive leg raising test (PLR). Continuous cardiac index (CI), stroke volume (SV), and stroke volume variation (SVV) were assessed with FloTracTM/EV1000™. Fluid responsiveness was defined as an increase in CI ≥ 10% after PLR. We compared the differences in measured variables between fluid responders and non-responders and tested the ability of ultrasonographic IJV indices to predict fluid responsiveness.

RESULTS

Fifty-four patients were included in the study. Seventeen (31.5%) were fluid responders. The responders demonstrated significantly lower inspiratory and expiratory diameters of the IJV at baseline, but IJV collapsibility was comparable (P = 0.7). Using the cut-off point of 20%, IJV collapsibility predicted fluid responsiveness with a sensitivity of 76.5% and specificity of 38.9%, ROC AUC 0.55.

CONCLUSION

In spontaneously breathing patients after surgical coronary revascularisation, collapsibility of the internal jugular vein did not predict fluid responsiveness.

Central Venous Waveform Analysis and Cardiac Output in a Porcine Model of Endotoxemic Hypotension and Resuscitation

BACKGROUND

Cardiac output (CO) is a valuable proxy for perfusion, and governs volume responsiveness during resuscitation from distributive shock. The underappreciated venous system has nuanced physiology that confers valuable hemodynamic information. In this investigation, deconvolution of the central venous waveform by the fast Fourier transformation (FFT) algorithm is performed to assess its ability to constitute a CO surrogate in a porcine model of endotoxemia-induced distributive hypotension and resuscitation.

STUDY DESIGN

Ten pigs were anesthetized, catheterized, and intubated. A lipopolysaccharides infusion protocol was used to precipitate low systemic vascular resistance hypotension. Four crystalloid boluses (10 cc/kg) were then given in succession, after which heart rate, mean arterial pressure, thermodilution-derived CO, central venous pressure (CVP), and the central venous waveform were collected, the last undergoing fast Fourier transformation analysis. The amplitude of the fundamental frequency of the central venous waveform's cardiac wave (f0-CVP) was obtained. Heart rate, mean arterial pressure, CVP, f0-CVP, and CO were plotted over the course of the boluses to determine whether f0-CVP tracked with CO better than the vital signs, or than CVP itself.

RESULTS

Distributive hypotension to a 25% mean arterial pressure decrement was achieved, with decreased systemic vascular resistance (mean 918 ± 227 [SD] dyne/s/cm-5 vs 685 ± 180 dyne/s/cm-5; p = 0.038). Full hemodynamic parameters characterizing this model were reported. Slopes of linear regression lines of heart rate, mean arterial pressure, CVP, f0-CVP, and CO were -2.8, 1.7, 1.8, 0.40, and 0.35, respectively, demonstrating that f0-CVP values closely track with CO over the 4-bolus range.

CONCLUSIONS

Fast Fourier transformation analysis of the central venous waveform may allow real-time assessment of CO during resuscitation from distributive hypotension, possibly offering a venous-based approach to clinical estimation of volume responsiveness.

Detecting Volemic, Cardiac, and Autonomic Responses From Hypervolemia to Normovolemia via Non-Invasive ClearSight Hemodynamic Monitoring During Hemodialysis: An Observational Investigation

Background: Unstable hemodynamics are not uncommon during hemodialysis (HD), which involves a rapid volume depletion, taking the patient from hypervolemia toward euvolemia. Since uremic patients commonly have cardiovascular comorbidities, hemodynamic changes during HD may reflect interactions among the volemic, cardiac, and autonomic responses to gradual volume depletion during ultrafiltration. Accurate identification of inappropriate responses helps with precisely managing intradialytic hypotension. Recently, the non-invasive ClearSight was reported to be able to detect causes of intraoperative hypotension. In this prospective observational study, we aimed to determine whether ClearSight could be used to detect patterns in stroke volemic, cardiac, and vasoreactive responses during HD. Methods: ClearSight was used to monitor chronic stable patients receiving maintenance HD. Data of mean arterial blood pressure (MAP), heart rate (HR), stroke volume index (SVI), cardiac index (CI), and calculated systemic vascular resistance index (SVRI) were obtained and analyzed to examine patterns in volemic, cardiac, and vasoreactive changes from T0 (before HD) until T8 in 30-min intervals (total 4 h). Results: A total of 56 patients with a mean age of 60.5 years were recruited, of which 40 of them were men. The average ultrafiltration volume at T8 was 2.1 ± 0.8 L. The changes in MAP and HR from T0 to T8 were non-significant. SVI at T7 was significantly lower than that at T1, T2, and T3. CI at T4 to T8 was significantly lower than that at T0. SVRI was significantly higher at T3 to T8 than at T0. Pearson's correlation coefficients between SVI and CI and between SVRI and MAP were positive at all time points. The correlation coefficients between SVRI and SVI and between CI and SVRI were significant and negative for all time points. Conclusion: ClearSight was able to detect patterns in hypervolemia during HD and was well tolerated for 4 h. CI decreased significantly after T4, with slightly decreased SVI. Ultrafiltration volume was not correlated with changes in SVI or CI. The vascular tone increased significantly, and this counteracted the reduced cardiac output after T4. With simultaneous monitoring on SVI, CI, and SVRI during HD, therefore, hypotension could be detected and managed by reducing the filtration rate or administering inotrope or vasopressors. Trial Registration: clinicaltrials.gov, ID: NCT03901794.

Contemporary Review of Hemodynamic Monitoring in the Critical Care Setting

Hemodynamic assessment remains the most valuable adjunct to physical examination and laboratory assessment in the diagnosis and management of shock. Through the years, multiple modalities to measure and trend hemodynamic indices have evolved with varying degrees of invasiveness. Pulmonary artery catheter (PAC) has long been considered the gold standard of hemodynamic assessment in critically ill patients and in recent years has been shown to improve clinical outcomes among patients in cardiogenic shock. The invasive nature of PAC is often cited as its major limitation and has encouraged development of less invasive technologies. In this review, the authors summarize the literature on the mechanism and validation of several minimally invasive and noninvasive modalities available in the contemporary intensive care unit. They also provide an update on the use of focused bedside echocardiography.

The use of point-of-care assessments and advanced hemodynamic monitoring in a patient with Eisenmenger syndrome for cesarean section: A case report

INTRODUCTION

Eisenmenger syndrome should be diagnosed before pregnancy and surgically corrected if possible. Cesarean section in a patient with Eisenmenger syndrome is high risk as morbidity and mortality are very high. Delivery in hospitals with intensive care units should be recommended. Use of point-of-care assessments and advanced monitors allow accurate management.

CASE PRESENTATION

A primigravid with congestive heart failure from a patent ductus arteriosus in Eisenmenger syndrome, presented with threatened preterm labor and uncontrolled hypertension prompting cesarean delivery under epidural anesthesia. Pre-induction focused echocardiography revealed normal right ventricular function and severe pulmonary hypertension. Intraoperatively, hemodynamics became unstable. The decision to use fluids, vasopressor and inotrope was guided by analyses of arterial pulse contour, central venous pressure waveform and blood exams. Hemodynamics improved and a live baby was delivered. Postoperative course was unremarkable.

DISCUSSION

The cause of hemodynamic instability must be accurately determined as inappropriate use of fluid or medication may be detrimental to a patient with Eisenmenger syndrome. In this case, advanced hemodynamic monitoring showed changes in central venous pressure, cardiac output and systemic vascular resistance which differentiated the causes of hypotension and desaturation. Point-of-care blood analysis showed acidosis and hypoxia which may have worsened the right-to-left shunt, contributing to the desaturation. Fluid and drug infusions to address identified problems were then guided by advanced monitors.

CONCLUSION

The use of point-of-care assessments and advanced hemodynamic monitoring allowed accurate diagnoses and goal-directed therapies leading to improved patient safety and outcomes. The need for prolonged intensive care in this case was prevented.

Changes in corrected carotid flow time induced by recruitment maneuver predict fluid responsiveness in patients undergoing general anesthesia

Non-invasive methods to assess patients' fluid responsiveness during lung-protective ventilation are needed. We hypothesized changes in the corrected carotid flow time induced by the recruitment maneuver predict fluid responsiveness under general anesthesia. Thirty patients undergoing general anesthesia in the supine position were prospectively enrolled. The study protocol was conducted when the patient was hemodynamically stable during surgery. Flow time was measured on Doppler images of the common carotid artery. Carotid flow time, heart rate, stroke volume, stroke volume variation, and pulse pressure variation were recorded before and after a recruitment maneuver at a continuous airway pressure of 30 cmH₂O for 30 s, and before and after volume expansion with 250 mL for 10 min. Patients were defined as fluid responders if the increase in stroke volume was > 10% after volume expansion. Twenty patients (67%) were fluid responders. All Doppler images for carotid flow time were obtained within 30 s. Changes in the corrected flow time accurately predicted fluid responsiveness (area under the curve: 0.82, 95% confidence interval [CI] 0.64-0.94, p = 0.002). The optimal threshold for changes in the corrected flow time was - 11.7% with a sensitivity of 95.0% (95% CI 75.1-99.9%) and a specificity of 80.0% (95% CI 44.4-97.5%). The gray-zone of changes in the corrected flow time was from - 25.1 to - 12.2% and included 12 patients (40%). Changes in the corrected carotid flow time were a useful, technically easy-to-perform, and non-invasive method to predict fluid responsiveness without a need for hemodynamic monitoring or arterial cannulation.

Ability of Carotid Corrected Flow Time to Predict Fluid Responsiveness in Patients Mechanically Ventilated Using Low Tidal Volume after Surgery

Predicting fluid responsiveness in patients under mechanical ventilation with low tidal volume (VT) is challenging. This study evaluated the ability of carotid corrected flow time (FTc) assessed by ultrasound for predicting the fluid responsiveness during low VT ventilation. Patients under postoperative mechanical ventilation and clinically diagnosed with hypovolemia were enrolled. Carotid FTc and pulse pressure variation (PPV) were measured at VT of 6 and 10 mL/kg predicted body weight (PBW). FTc was calculated using both Bazett’s (FTcB) and Wodey’s (FTcW) formulas. Fluid responsiveness was defined as a ≥15% increase in the stroke volume index assessed by FloTrac/Vigileo monitor after administration of 8 mL/kg of balanced crystalloid. Among 36 patients, 16 (44.4%) were fluid responders. The areas under the receiver operating characteristic curves (AUROCs) for the FTcB at VT of 6 and 10 mL/kg PBW were 0.897 (95% confidence interval [95% CI]: 0.750–0.973) and 0.895 (95% CI: 0.748–0.972), respectively. The AUROCs for the FTcW at VT of 6 and 10 mL/kg PBW were 0.875 (95% CI: 0.722–0.961) and 0.891 (95% CI: 0.744–0.970), respectively. However, PPV at VT of 6 mL/kg PBW (AUROC: 0.714, 95% CI: 0.539–0.852) showed significantly lower accuracy than that of PPV at VT of 10 mL/kg PBW (AUROC: 0.867, 95% CI: 0.712–0.957; p = 0.034). Carotid FTc can predict fluid responsiveness better than PPV during low VT ventilation. However, further studies using automated continuous monitoring system are needed before its clinical use.

The Effect of Changing Arterial Transducer Position on Stroke Volume Measurements Using FloTrac System Version 4.0: A Pilot Experimental Study

Supplemental Digital Content is available in the text.

Objectives:

We conducted a pilot study using an experimental study protocol to evaluate the measurement error of arterial pulse contour analysis-derived stroke volume due to improper transducer leveling during the passive leg raising test and the impact of such error on the determination of fluid responsiveness.

Design:

Prospective observational study.

Setting:

A medical-surgical ICU at a tertiary referral center in Kobe, Japan.

Patients:

Consecutive critically ill adult patients using the FloTrac system Version 4.0 (Edwards Lifesciences, Irvine, CA) for hemodynamic monitoring between September 1, 2018, and November 31, 2018.

Interventions:

None.

Measurements and Main Results:

Using 20 patients, we estimated the change in the zero-reference level of an arterial transducer during head-down tilting as the vertical distance between the zero-reference levels of the transducer in the 45° semi-recumbent and supine positions. Using the FloTrac system Version 4.0, we recorded the hemodynamic variables every 20 seconds for 180 seconds at each of the following three points: 1) baseline, 2) after the transducer was elevated by the predetermined distance, and 3) after the transducer had returned to baseline. With respect to the predetermined change in the transducer level, a mean value of 18 ± 3 cm resulted in an increase in stroke volume measurement (mean value, 11 mL/beat; 95% CI, 10–13). This value corresponded to 20% (95% CI, 18–23%) of the baseline value 20 seconds after changing the transducer level. A significant correlation was observed between the predetermined change in the transducer level and the increase in the measured stroke volume (r² = 0.58; p < 0.001).

CONCLUSIONS:

When using the FloTrac system Version 4.0, a rapid increase in stroke volume was observed after elevating the arterial transducer. Clinicians and researchers are advised that proper leveling of the arterial transducer is necessary in order to accurately assess the change in arterial pulse contour analysis-derived stroke volume during the passive leg raising test.

Fluid Responsiveness in the Critically Ill Patient

Accurate assessment of intravascular volume status in critically ill patients remains a very challenging task. Recent data have shown adverse outcomes in critically ill patients with either inadequate or overaggressive fluid therapy. Understanding the tools and techniques available for accurate volume assessment is imperative. This article discusses the concept of fluid responsiveness and reviews methods for assessing fluid responsiveness in critically ill patients.

Carotid Artery Flow Time Measured by Point-of-Care Ultrasound Correlates with Volume Changes in Pediatric Hemodialysis Patients

Carotid artery flow time corrected for heart rate (CFTc) correlates with intravascular volume changes in adults but has not been studied adequately in the pediatric population. We studied how fluid status changes correlate with CFTc in pediatric patients undergoing hemodialysis. This prospective observational study involved pediatric patients aged 5-18 y undergoing chronic hemodialysis at a tertiary care children's hospital in the United States. We measured CFTc by point-of-care ultrasound before and after each hemodialysis session, including passive leg raise. One hundred sixty-eight CFTc measurements were obtained from a total of 21 patient encounters. Post-dialysis CFTc decreased by 21.7 ms (95% confidence interval: 12.3-31.0) (p < 0.001). Pre- and post-dialysis ∆CFTc measurements were proportionally correlated with volume removed in dialysis adjusted for weight (mL/kg) (R² = 0.224, p = 0.03). There was no significant change in mean CFTc with passive leg raise before or after hemodialysis. In children on hemodialysis, changes in CFTc were moderately correlated with decrease in intravascular volume after hemodialysis.

Changes in Stroke Volume Variation Induced by Passive Leg Raising to Predict Fluid Responsiveness in Cardiac Surgical Patients With Protective Ventilation

OBJECTIVES

Stroke volume variation (SVV) has been used to predict fluid responsiveness. The authors hypothesized the changes in SVV induced by passive leg raising (PLR) might be an indicator of fluid responsiveness in patients with protective ventilation after cardiac surgery.

DESIGN

A prospective single-center observational study.

SETTING

A single cardiac surgery intensive care unit at a tertiary hospital.

PARTICIPANTS

A total of 123 patients undergoing cardiac surgery with hemodynamic instability. Tidal volume was set between 6 and 8 mL/kg of ideal body weight.

INTERVENTIONS

PLR maneuver, fluid challenge.

MEASUREMENTS AND MAIN RESULTS

SVV was continuously recorded using pulse contour analysis before and immediately after a PLR test and after fluid challenge (500 mL of colloid given over 30 min). Sixty-three (51.22%) patients responded to fluid challenge, in which PLR and fluid challenge significantly increased the SV and decreased the SVV. The decrease in SVV induced by PLR was correlated with the SV changes induced by fluid challenge. A 4% decrease in the SVV induced by PLR-discriminated responders to fluid challenge with an area under the curve of 0.90. The gray zone identified a range of SVV changes induced by PLR (between -3.94% and -2.91%) for which fluid responsiveness could not be predicted reliably. The gray zone included 15.45% of the patients. The SVV at baseline predicted fluid responsiveness with an area under the curve of 0.72.

CONCLUSIONS

Changes in the SVV induced by PLR predicted fluid responsiveness in cardiac surgical patients with protective ventilation.

Fluid Response Evaluation in Sepsis Hypotension and Shock: A Randomized Clinical Trial

BACKGROUND

Fluid and vasopressor management in septic shock remains controversial. In this randomized controlled trial, we evaluated the efficacy of dynamic measures (stroke volume change during passive leg raise) to guide resuscitation and improve patient outcome.

RESEARCH QUESTION

Will resuscitation that is guided by dynamic assessments of fluid responsiveness in patients with septic shock improve patient outcomes?

STUDY DESIGN AND METHODS

We conducted a prospective, multicenter, randomized clinical trial at 13 hospitals in the United States and United Kingdom. Patients presented to EDs with sepsis that was associated hypotension and anticipated ICU admission. Intervention arm patients were assessed for fluid responsiveness before clinically driven fluid bolus or increase in vasopressors occurred. The protocol included reassessment and therapy as indicated by the passive leg raise result. The control arm received usual care. The primary clinical outcome was positive fluid balance at 72 hours or ICU discharge, whichever occurred first.

RESULTS

In modified intent-to-treat analysis that included 83 intervention and 41 usual care eligible patients, fluid balance at 72 hours or ICU discharge was significantly lower (-1.37 L favoring the intervention arm; 0.65 ± 2.85 L intervention arm vs 2.02 ± 3.44 L usual care arm; P = .021. Fewer patients required renal replacement therapy (5.1% vs 17.5%; P = .04) or mechanical ventilation (17.7% vs 34.1%; P = .04) in the intervention arm compared with usual care. In the all-randomized intent-to-treat population (102 intervention, 48 usual care), there were no significant differences in safety signals.

INTERPRETATION

Physiologically informed fluid and vasopressor resuscitation with the use of the passive leg raise-induced stroke volume change to guide management of septic shock is safe and demonstrated lower net fluid balance and reductions in the risk of renal and respiratory failure. Dynamic assessments to guide fluid administration may improve outcomes for patients with septic shock compared with usual care.

CLINICAL TRIAL REGISTRATION

NCT02837731.

Inflammatory response and optimalisation of perioperative fluid administration during hyperthermic intraoperative intraperitoneal chemotherapy surgery

Background

Surgical cytoreduction and simultaneous hyperthermic intraoperative intraperitoneal chemotherapy (HIPEC) for peritoneal carcinomatosis has a high incidence of postoperative complications. Inadequate intraoperative volume therapy is a known risk factor for the development of postoperative complications. Another possible risk factor is the inflammatory response due to surgery and HIPEC. The aim of this observational pilot study was to monitor fluid intake in the first 24 hours peri- and postoperative by using a non-invasive cardiac output indicator. Furthermore, we measured circulating cytokines and evaluated the possible relation of these changes of inflammatory response with the non-invasive monitored fluid management.

Methods

Twenty-four patients undergoing cytoreductive surgery and HIPEC for peritoneal carcinomatosis were included. Patients were randomised into either a liberal fluid management group using intra-arterial blood pressure and central venous pressure measurement or a restrictive group by using intra-arterial blood pressure and central venous pressure measurement with FloTrac/Vigileo monitoring. Cytokines were measured with multiplex immunoassays.

Results

We found no difference in the amount of fluid administration in patients undergoing HIPEC surgery with FloTrac/Vigileo monitoring compared to standard care. Furthermore, there was no difference in mortality, ICU and hospital length of stay between both groups. A severe inflammatory response was seen in all patients after the HIPEC procedure with a rapid increase of interleukins and C-reactive protein (CRP). There was however no difference between our intervention and control group in the severity of this reaction. Finally, we found no relation between the severity of the inflammatory response and mortality, or a composite end-point of mortality and severe complications within 30 days postoperative.

Conclusions

FloTrac/Vigileo monitoring does not lead to a more restrictive fluid administration and does not influence short-term clinical course in patients undergoing HIPEC surgery. The procedure itself leads to a severe inflammatory response, which is not affected by the use of FloTrac/Vigileo. Our data do not support the use of FloTrac/Vigileo monitoring in patients undergoing HIPEC surgery concerning fluid restrictive management.

Euvolemia-A critical target in the management of acute kidney injury

It has been clearly established that critically ill patients with sepsis require prompt fluid resuscitation. The optimal amount of fluid and when to taper this resuscitation is less clear. There is a growing evidence that fluid overload leads to acute kidney injury, and increased morbidity and mortality. A clinician's best intentions in resuscitating a patient can lead to too much of a good thing. Currently, there are several bedside tools to aid in determining a patient's response to a fluid challenge as well as in the assessment of the current volume status. Guidelines are not available on the exact rate of fluid overload removal and what medicinal or mechanical modality is most favorable. We discuss our experience and an examination of the literature on the problems with fluid overload, and how a patient may benefit from forced fluid removal.

Internal jugular vein variability predicts fluid responsiveness in cardiac surgical patients with mechanical ventilation

BACKGROUND

To evaluate the efficacy of using internal jugular vein variability (IJVV) as an index of fluid responsiveness in mechanically ventilated patients after cardiac surgery.

METHODS

Seventy patients were assessed after cardiac surgery. Hemodynamic data coupled with ultrasound evaluation of IJVV and inferior vena cava variability (IVCV) were collected and calculated at baseline, after a passive leg raising (PLR) test and after a 500-ml fluid challenge. Patients were divided into volume responders (increase in stroke volume ≥ 15%) and non-responders (increase in stroke volume < 15%). We compared the differences in measured variables between responders and non-responders and tested the ability of the indices to predict fluid responsiveness.

RESULTS

Thirty-five (50%) patients were fluid responders. Responders presented higher IJVV, IVCV and stroke volume variation (SVV) compared with non-responders at baseline (P < 0.05). The relationship between IJVV and SVV was moderately correlated (r = 0.51, P < 0.01). The areas under the receiver operating characteristic (ROC) curves for predicting fluid responsiveness were 0.88 (CI 0.78-0.94) for IJVV compared with 0.83 (CI 0.72-0.91), 0.97 (CI 0.89-0.99), 0.91 (CI 0.82-0.97) for IVCV, SVV, and the increase in stroke volume in response to a PLR test, respectively.

CONCLUSIONS

Ultrasound-derived IJVV is an accurate, easily acquired noninvasive parameter of fluid responsiveness in mechanically ventilated postoperative cardiac surgery patients, with a performance similar to that of IVCV.

Passive leg raising test with minimally invasive monitoring: the way forward for guiding septic shock resuscitation?

Background

Swift and adequate fluid loading is a cornerstone of septic shock therapy. Yet, careful assessment of volume responsiveness and volume amount during the resuscitation process is a prerequisite. Both overzealous initial fluid administration and late fluid overload are harmful and may be associated with increased mortality.

Main body

Static (i.e., central venous or pulmonary artery occlusion) pressure readings are erroneous for monitoring fluid resuscitation and should be abandoned. Dynamic measurements (i.e., stroke volume and pulse pressure variation) better predict fluid responsiveness than static filling pressures but the conditions necessary for these parameters to correctly evaluate preload dependency are frequently not met. The passive leg raising maneuver as a means to alter biventricular preload in combination with real-time measurement of cardiac output changes is an easy-to-use, fast, relatively unbiased, and accurate bedside test to guide fluid management and to avoid fluid overload during early septic shock treatment. Moreover, PLR may also be particularly useful to assist various treatments that trigger fluid removal during the “de-resuscitation” phase of septic shock.

Conclusions

The passive leg raising maneuver in combination with real-time measurement of cardiac output changes is an easy-to-use, fast, relatively unbiased, and accurate bedside test to guide fluid management during septic shock.