Measures Of Fluid Responsiveness Research Articles

Fluid management in shock patients : New targets in the initial phase of shock

Early i.v. fluid administration is a cornerstone in modern therapy of shock, especially in septic shock. However, there is much uncertainty concerning the amount and rate of fluid and which goals and measures could guide fluid management. Administering the optimal fluid volume is important because fluid overload can lead to severe negative consequences like organ failure and worsening of patient's outcome. This review aims to describe the importance of fluid therapy and discuss possible strategies in fluid management as well as possible measurements and goals to guide such therapy. There is no single measurement to guide fluid management alone. It is important to assess fluid responsiveness, which together with multiple other parameters can be used to repeatedly assess optimal fluid management. However, it has also not been shown that assessing fluid responsiveness can improve outcome. After the initial resuscitation, further fluid administration should be determined by individual patient factors and measures of fluid responsiveness. Amore restrictive fluid management with early vasopressor administration seems to be increasingly used in modern fluid management. However many questions regarding optimal fluid management remain to be solved.

Correlation coefficient between plethysmographic variability index and Systolic Pressure Variation as an indicator for fluid responsiveness in hypotensive patients in the ICU/OT

BackgroundPrediction of fluid responsiveness in hypotensive patients is a challenge. The correlation between a novel noninvasive dynamic indicator, Pleth Variability Index (PVI ®), and a gold-standard Systolic Pressure Variation (SPV) as a measure of fluid responsiveness was assessed in the Intensive Care Unit (ICU) or Operation Theatre (OT) in a tertiary care hospital. MethodsA prospective experimental study was conducted over a span of one year on 100 mechanically ventilated patients with hypotension. Vital parameters along with SPV and PVI ® were recorded before and after a standard volume expansion protocol. A 10% SPV threshold was used to define fluid responders and nonresponders. ResultsPearson’s correlation graph at baseline showed positive correlation between PVI ® and SPV (r = 0.59, p-value = 0.001). Strength of correlation was comparatively less but still showed positive correlation at 15 (r = 0.39, p-value = 0.009) and 30 (r = 0.404, p-value = 0.004) minutes of fluid bolus. The Bland Altman analysis of baseline values of PVI ® and SPV showed good agreement with a mean bias of 9.05. Percentage change of PVI ® and SPV over 30 min showed a statistically significant positive correlation in the responder group (r = 0.53, p < 0.05). A threshold value of PVI ® more than 18% before volume expansion differentiated fluid responders and nonresponders with a sensitivity of 75% and specificity of 67%, with an area under Receiver Operating Characteristic (ROC) of 0.78. ConclusionA positive correlation exists between SPV and PVI ®, justifying the use of noninvasive PVI ® in a clinical setting of hypotension.

Carotid Doppler Measurement Variability in Functional Hemodynamic Monitoring: An Analysis of 17,822 Cardiac Cycles.

OBJECTIVES:Carotid Doppler ultrasound is used as a measure of fluid responsiveness, however, assessing change with statistical confidence requires an adequate beat sample size. The coefficient of variation helps quantify the number of cardiac cycles needed to adequately detect change during functional hemodynamic monitoring.DESIGN:Prospective, observational, human model of hemorrhage and resuscitation.SETTING:Human physiology laboratory at Mayo Clinic.SUBJECTS:Healthy volunteers.INTERVENTIONS:Lower body negative pressure.MEASUREMENTS AND MAIN RESULTS:We measured the coefficient of variation of the carotid artery velocity time integral and corrected flow time during significant cardiac preload changes. Seventeen-thousand eight-hundred twenty-two cardiac cycles were analyzed. The median coefficient of variation of the carotid velocity time integral was 8.7% at baseline and 11.9% during lowest-tolerated lower body negative pressure stage. These values were 3.6% and 4.6%, respectively, for the corrected flow time.CONCLUSIONS:The median coefficient of variation values measured in this large dataset indicates that at least 6 cardiac cycles should be averaged before and after an intervention when using the carotid artery as a functional hemodynamic measure.

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.

The predictive value of the Pleth Variability Index on fluid responsiveness in spontaneously breathing anaesthetized children-A prospective observational study.

BackgroundIn children, the preoperative hydration status is an important part of the overall clinical assessment. The assumed preoperative fluid deficit is often routinely replaced during induction without knowing the child's actual fluid status.AimWe investigated the predictive value of the Pleth Variability Index as a measure of fluid responsiveness in spontaneously breathing anesthetized children.MethodsPleth Variability Index, stroke volume and Cardiac Index, measured by electrovelocimetry, mean blood pressure, and heart rate were recorded during anesthesia induction in 50 pediatric patients <6 years. Baseline values were compared to values recorded after administration of 10 mL/kg of Ringer's lactate and during two passive leg raising tests (before and after fluid administration). Fluid responsiveness was defined as an increase of ≥10% in stroke volume.ResultsOnly in fluid responsive patients, Pleth Variability Index values were higher before fluid administration than thereafter (21.4 ± 5.9% vs 15.0 ± 9.4%, 95% CI of difference 1.1 to 11.8%, P = .02). Pleth Variability Index values at baseline were higher in fluid responders (21.4 ± 5.9%) than in fluid nonresponders (15.3 ± 7.7%), 95% CI of difference 1.6 to 10.6%, P = .009. The area under the receiver operating curve indicating fluid responsiveness was 0.781 (95% CI 0.623 to 0.896, P = .0002), with the highest sensitivity (82%) and specificity (70%) at a Pleth Variability Index of >15% (Positive predictive value 2.71 (95% CI: 1.4 to 5.2)). Only in fluid responders, the Pleth Variability Index decreased during passive leg raising, while stroke volume increased.ConclusionsThe Pleth Variability Index may be of additional value to predict fluid responsiveness in spontaneously breathing anesthetized children. A significant overlap in baseline Pleth Variability Index values between fluid responsive and nonfluid responsive patients does not allow a reliable recommendation as to a cut off value.

The role of internal jugular vein and inferior vena cava distensibility indices as parameters of fluid responsiveness in mechanically ventilated septic shock patients

Context The use of dynamic parameters for the assessment of fluid responsiveness in septic shock patients has increased in recent years. Aims In this study, we examined the ability of internal jugular vein distensibility index (ΔDIJV) and inferior vena cava distensibility index (ΔDIVC) to predict volume responsiveness in the management of mechanically ventilated septic shock patients. Settings and design Prospective interventional cohort study. Patients and methods This study enrolled 34 septic shock patients. Hemodynamic data coupled with echocardiographic assessment of cardiac index (ΔCI), ΔDIVC, and ΔDIJV were assessed before and after 7 ml/kg fluid challenge. Patients were considered as fluid responders if a rise in ΔCI more than or equal to 15% took place after volume expansion, and if ΔCI was less than 15%, the patients were considered nonresponders. Results The area under the curve of ΔDIVC was 0.940 with the best cut off value of less than or equal to 13.6% with sensitivity, specificity, positive predictive value, and negative predictive value of 94.74, 80.00, 85.7, and 92.3%, respectively. While the area under the curve for ΔDIJV was 0.900 with the best cutoff value of less than or equal to 11.6% with sensitivity, specificity, positive predictive value, and negative predictive value of 84.21, 80.00, 84.2, and 80.0%, respectively. Conclusions Ultrasonic evaluation of respirophasic changes of internal jugular vein is a simple, easy, and readily accessible bedside measure of fluid responsiveness in mechanically ventilated, sedated septic shock patients. ΔDIJV can predict fluid responsiveness with good sensitivity, specificity, and overall accuracy. Meanwhile, ΔDIVC is still more sensitive with better overall accuracy.

Assessment of fluid responsiveness by inferior vena cava diameter variation in post-pneumonectomy patients.

AimFirst, the inferior vena cava dilatation index (DIVC) was measured by ultrasound, and then the reliability of DIVC as an indicator to predict volume responsiveness in patients undergoing mechanical ventilation after pneumonectomy was evaluated.MethodsPulse indicator continuous cardiac output (Picco) as gold standard was performed to sedated mechanically ventilated post‐pneumonectomy patients in intensive care unit of Nanjing Thoracic Hospital from August 2014 to December 2016. Meanwhile, ultrasound measurement to inferior vena cava (IVC) diameter at the end inspiration (D max) and the end of expiration (D min) was performed. DIVC = (D max − D min)/D min. Above values were recorded at baseline and then after fluid resuscitation challenge (7 mL/kg hydroxyethyl starch). An increase in cardiac index of more than 15% was used as the standard for fluid responsiveness. Patients were divided into responsive group and non‐responsive group. A receiver operating characteristic (ROC) curve was then used to determine the sensitivity and specificity of DIVC in predicting fluid responsiveness after pneumonectomy.ResultsEighteen patients were enrolled. 10 patients were divided into responsive group and eight in non‐responsive group. DIVC in responsive group was significantly higher than in non‐responsive group (P < 0.01). By setting DIVC ≥ 15% as a measure of fluid responsiveness, sensitivity was 81.8% and specificity was 85.7%.ConclusionDIVC is a reliable indicator of capacity responsiveness in mechanically ventilated post‐pneumonectomy patients.

Abstract PR095

Background & Objectives: Dynamic indicators of fluid responsiveness have been established to be more accurate indicators of preload than static indicators such as Central Venous Pressure. Our aim was to assess the correlation between a non invasive dynamic indicator, Plethysmography Variability Index (PVI) and Systolic Pressure Variation (SPV) as a measure of fluid responsiveness. Materials & Methods: A prospective experimental study was conducted on 50 ICU patients over one year. After inclusion criteria were met in prospective subjects, vital parameters including blood pressure (systolic, diastolic and mean), heart rate, and Oxygen Saturation (SpO2) were recorded. Central venous pressure was also recorded if central line was present. Simultaneous measurement of SPV from an invasive arterial line trace and PVI using pulse-oximetry was carried out. A fluid challenge was administered with 20 ml/kg Ringer’s Lactate fluid over 10 min. Vital parameters, SPV and PVI were recorded every 5 min till 30 min after the fluid challenge. Results: Based on a cut of a baseline SPV of 10 %, the sample group was divided into two sub groups; Fluid Responders (32) and Non Responders (18). Baseline values of PVI were found to be significantly higher in the responder group (22.8±9.5) vs. the non responder group (14.7±5.5), (p < 0.001). Pearson correlation coefficient also showed positive correlation (r = 0.6, p=0.001) between baseline PVI and SPV values. Similar findings were observed even after 15 minutes and 30 minutes of fluid challenge (r=0.4). A threshold vale of PVI more than 18% before volume expansion differentiated fluid responders and non responders with a sensitivity of 75 % and specificity of 67 % with area under ROC of 0.78, which was in keeping with other similar studies.Conclusion: There exists a positive correlation between SPV and PVI, which justifies the use of PVI in a clinical setting of hypotension suspected to be due to hypovolemia, because of its non invasiveness and ease of use. Although more studies are required, especially in an ICU setting, before it becomes an established tool for the same.

Passive leg raising and compression stockings: a note of caution

In a recent editorial in Critical Care, Monnet and Teboul emphasize the value of passive leg raising (PLR) as a reliable bedside indicator of fluid responsiveness in critically ill patients [1]. This is because PLR induces changes in venous return, regardless of the mode of ventilation or the underlying cardiac arrhythmias. In their eloquently written editorial, they provide five practical rules for performing a PLR maneuver. The authors state that during PLR about 300 mL of blood is auto-transfused from the lower limbs and splanchnic circulation into the central compartment, resulting in an increased cardiac output. This maneuver has been validated in cohorts of patients with either hypovolaemic or septic shock [2, 3]. It is a prerequisite of the test that the volume of blood that is auto-transfused be sufficient to increase mean circulatory pressure which drives venous return [3]. We hypothesize that this may not be the situation in all patients and that, if there is no change in cardiac output, blood pressure, or right atrial pressure [4], an inadequate volume of blood will be returned to the right heart. This may be relevant in patients with elastic compression stockings, which are widely used to prevent venous thromboembolism in critically ill patients. The effectiveness of PLR as a measure of fluid responsiveness can be compromised by elastic compression stockings [5]. Consequently, we would recommend that elastic compression stockings be routinely removed prior to the PLR maneuver.

Reliable assessment of perfusion is the Holy Grail of intensive care.

Reliable assessment of perfusion is the Holy Grail of intensive care.

Fluid responsiveness is about stroke volume, and not pulse pressure Yogi: the power of Doppler fluid management and cardiovascular monitoring.

Fluid infusion is one of the most common critical care interventions, yet approximately 50 % of all fluid interventions are unnecessary and potentially harmful. An improved approach to identification of fluid responsiveness is of clinical importance. Currently fluid responsiveness is most frequently identified by blood pressure (BP) measurements or a surrogate. However fluid responsiveness is simply the increase in stroke volume (SV) associated with volume expansion, and may not be reflected in BP or BP surrogates. Guyton demonstrated that BP = CO x SVR, and it is know that baroreceptor mediated autonomic nervous system regulation of SV and SVR to preserve BP may mask significant and critical changes in haemodynamics. Dr Pinsky in his recent J Clin Monit Comput Editorial evaluated the relative merits of pulse pressure variability (PPV) methods, a variant on BP measurement, for assessment of fluid responsiveness and promoted the use of physiologic challenges to augment the applicability of PPV. However this guidance is only half right. This letter reminds clinicians of the physiologic limitations of PPV as a measure of fluid responsiveness, even when combined with physiologic challenges, and recommends the replacement of BP with SV measurements. The combination of accurate Doppler measurement of SV and physiologic challenges, as Dr Pinsky recommends, is a physiologically rational and effective approach to identification of fluid responsiveness with established evidence. The direct monitoring of SV and SV changes has the potential to improve a long standing critical care and anaesthetic conundrum; when to give fluid and when to stop.

Colloid Update

This update aims to provide an evidence based review of natural and synthetic colloids with a special emphasis on the various generations of the synthetic colloid hydroxyethyl starch. The effect of 1(st), 2(nd) and 3(rd) generation hetastarches on bleeding, coagulopathy, acute kidney injury and mortality will be discussed. The results of randomised controlled trials addressing morbidity and mortality outcomes of colloid versus crystalloid resuscitation in critically ill patients will be described. In addition, the rationale and evidence behind early goal directed fluid therapy (EGDFT) including a practical approach to assessment of dynamic measures of fluid responsiveness will be presented.

232: Sonodynamic Comparison of Systolic Blood Pressure to Aortic Velocity Time Integral Measurements as a Measure of Fluid Responsiveness In Non-Traumatic Symptomatic Hypotensive Emergency Department Patients

232: Sonodynamic Comparison of Systolic Blood Pressure to Aortic Velocity Time Integral Measurements as a Measure of Fluid Responsiveness In Non-Traumatic Symptomatic Hypotensive Emergency Department Patients

Targeted fluid administration for major surgery

Summary Targeted Fluid Adminstration (TFA) is a technique using less invasive cardiac output monitors to guide individualised intra-operative fluid therapy. Typically, the anaesthetist administers boluses of approximately 200–250 ml of colloid solution whilst measuring changes in stroke volume or another measure of fluid responsiveness, such as stroke volume variation. When the stroke volume measurements indicate that the cardiovascular system is no longer fluid responsive, the patient is assumed to be close to the upper flat phase of the Frank–Starling Curve. Research using TFA suggests that post-operative complications such as ileus and length of hospital stay are reduced when fluid therapy is managed in this way. Most of the positive evidence for TFA has been achieved using the oesophageal Doppler (CardioQ, Deltex Medical, Chichester UK), although other cardiac output monitors are available, there are few clinical outcome studies that justify their use in routine practice. Widespread adoption of TFA for patients undergoing major surgery will help achieve the goals of enhanced recovery.