Pleth Variability Index Predicts Fluid Responsiveness in Mechanically Ventilated Adults During General Anesthesia for Noncardiac Surgery

Goal-directed fluid therapy guided by plethysmographic variability index versus conventional liberal fluid therapy in neonates undergoing abdominal surgery: A prospective randomized controlled trial

BACKGROUND

Intraoperative fluid therapy maintains normovolemia, normal tissue perfusion, normal metabolic function, normal electrolytes, and acid-base status. Plethysmographic variability index has been shown to predict fluid responsiveness but its role in guiding intraoperative fluid therapy is still elusive.

AIMS

The aim of the present study was to compare intraoperative goal-directed fluid therapy based on plethysmographic variability index with liberal fluid therapy in term neonates undergoing abdominal surgeries.

METHODS

A prospective randomized controlled study was conducted in a tertiary care centre, over a period of 18 months. A total of 30 neonates completed the study out of 132 neonates screened. Neonates with tracheoesophageal fistula, congenital diaphragmatic hernia, congenital heart disease, respiratory disorders, creatinine clearance <90 mL/min and who were hemodynamically unstable were excluded. Neonates were randomized to goal-directed fluid therapy group where the plethysmographic variability index was targeted at <18 or liberal fluid therapy group. Primary outcome was comparison of total amount of fluid infused intraoperatively in both the groups. Secondary outcomes included intraoperative and postoperative arterial blood gas parameters, biochemical parameters, use of vasopressors, number of fluid boluses, complications and duration of hospital stay.

RESULTS

There was no significant difference in total intraoperative fluid infused [90 (84-117.5 mL) in goal-directed fluid therapy and 105 (85.5-144.5 mL) in liberal fluid therapy group (p = .406)], median difference (95% CI) -15 (-49.1 to 19.1). There was a decrease in serum lactate levels in both groups from preoperative to postoperative 24 h. The amount of fluid infused before dopamine administration was significantly higher in liberal fluid therapy group (58 [50.25-65 mL]) compared to goal-directed fluid therapy group (36 [22-44 mL], p = .008), median difference (95% CI) -22 (-46 to 2). In postoperative period, the total amount of fluid intake over 24 h was comparable in two groups (222 [204-253 mL] in goal-directed fluid therapy group and 224 [179.5-289.5 mL] in liberal fluid therapy group, p = .917) median difference (95% CI) cutoff -2 (-65.3 to 61.2).

CONCLUSION

Intraoperative plethysmographic variability index-guided goal-directed fluid therapy was comparable to liberal fluid therapy in terms of total volume of fluid infused in neonates during perioperative period. More randomized controlled trials with higher sample size are required.

TRIAL REGISTRATION

Central Trial Registry of India (CTRI/2020/02/023561).

Predicting fluid responsiveness using esophagus Doppler monitoring and pulse oximetry derived pleth variability index; retrospective analysis of a hemodynamic study

BACKGROUND

Fluid therapy during major surgery can be managed by providing repeated bolus infusions until stroke volume no longer increases by ≥ 10%. However, the final bolus in an optimization round increases stroke volume by < 10% and is not necessary. We studied how different cut-off values for the hemodynamic indications given by esophagus Doppler monitoring, as well as augmentation by pulse oximetry, are associated with a higher or smaller chance that stroke volume increases by ≥ 10% (fluid responsiveness) before fluid is infused.

METHODS

An esophagus Doppler and a pulse oximeter that displayed the pleth variability index were used to monitor the effects of a bolus infusion in 108 patients undergoing goal-directed fluid therapy during major open abdominal surgery.

RESULTS

The analyzed data set comprised 266 bolus infusions. The overall incidence of fluid responsiveness was 44%, but this varied greatly depending on pre-infusion hemodynamics. The likelihood of being fluid-responsive was 30%-38% in the presence of stroke volume > 80 mL, corrected flow time > 360 ms, or pleth variability index < 10%. The likelihood was 21% if stroke volume had decreased by <8% since the previous optimization, which decreased to 0% if combined with stroke volume > 100 mL. By contrast, the likelihood of fluid responsiveness increased to 50%-55% when stroke volume ≤ 50 mL, corrected flow time ≤ 360 ms, or pleth variability index ≥ 10. A decrease in stroke volume by > 8% since the previous optimization was followed by a 58% likelihood of fluid responsiveness that, in combination with any of the other hemodynamic variables, increased to 66%-76%.

CONCLUSIONS

Single or combined hemodynamic variables provided by esophagus Doppler monitoring and pulse oximetry derived pleth variability index could help clinicians avoid unnecessary fluid bolus infusions.

Blood Pressure Goals in Critically Ill Patients

Blood pressure goals in the intensive care unit (ICU) have been extensively investigated in large datasets and have been associated with various harm thresholds at or greater than a mean pressure of 65 mm Hg. While it is difficult to perform interventional randomized trials of blood pressure in the ICU, important evidence does not support defense of a higher pressure, except in retrospective database analyses. Perfusion pressure may be a more important target than mean pressure, even more so in the vulnerable patient population. In the cardiac ICU, blood pressure targets are tailored to specific cardiac pathophysiology and patient characteristics. Generally, the goal is to maintain adequate blood pressure within a certain range to support cardiac function and to ensure end organ perfusion. Individualized targets demand the use of both invasive and noninvasive monitoring modalities and frequent titration of medications and/or mechanical circulatory support where necessary. In this review, we aim to identify appropriate blood pressure targets in the ICU, recognizing special patient populations and outlining the risk factors and predictors of end organ failure.

Comparison of two techniques of goal directed fluid therapy in elective neurosurgical patients - a randomized controlled study

BACKGROUND

Goal directed fluid therapy (GDFT) may be a rational approach to adopt in neurosurgical patients, in whom intravascular volume optimization is of utmost importance. Most of the parameters used to guide GDFT are derived invasively. We postulated that the total volume of intraoperative intravenous fluid administered during elective craniotomy for supratentorial brain tumours would be comparable between two groups receiving GDFT guided either by the non-invasively derived plethysmography variability index (PVI) or by stroke volume variation (SVV).

METHODS

60 ASA category 1, 2 and 3 patients between 18 and 70 years of age were randomized to receive intraoperative fluid guided either by SVV (SVV group; n = 31) or PVI (PVI group; n = 29). The total volume of fluid administered intraoperatively was recorded. Serum creatinine was measured before the surgery, at the end of the surgery, 24 h after surgery and on the fifth post-operative day. Arterial cannulation was performed before induction in all patients. Serum lactate was measured before induction, once in 2 h intraoperatively, at the end of the surgery and 24 h after the surgery. Brain relaxation score was assessed by the surgeon during dural opening and dural closure. Patients were followed up till discharge or death. The duration of mechanical ventilation and the duration of hospital stay was noted for all patients.

RESULTS

The volume of fluid given intraoperatively was significantly higher in the SVV group (p = 0.005). The two groups were comparable with respect to serum lactate and serum creatinine measured at pre-determined time intervals. Brain relaxation score was also comparable between the groups. SVV and PVI displayed moderate to strong correlation intraoperatively. The duration of mechanical ventilation and the length of the hospital stay were comparable between the two groups.

CONCLUSIONS

PVI and SVV are equally effective in guiding GDFT in adults undergoing elective craniotomy for supratentorial brain tumours.

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

BACKGROUND

We 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.

METHODS

Stroke 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.

RESULTS

Analysis 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).

CONCLUSIONS

The 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 REGISTRATION

ACTRN12615000125527.

Reliability of pleth variability index in predicting preload responsiveness of mechanically ventilated patients under various conditions: a systematic review and meta-analysis

Background

Goal-directed volume expansion is increasingly used for fluid management in mechanically ventilated patients. The Pleth Variability Index (PVI) has been shown to reliably predict preload responsiveness; however, a lot of research on PVI has been published recently, and update of the meta-analysis needs to be completed.

Methods

We searched PUBMED, EMBASE, Cochrane Library, Web of Science (updated to November 7, 2018) and the associated references. Relevant authors and researchers had been contacted for complete data.

Results

Twenty-five studies with 975 mechanically ventilated patients were included in this meta-analysis. The area under the curve (AUC) of receiver operating characteristics (ROC) to predict preload responsiveness was 0.82 (95% confidence interval (CI) 0.79–0.85). The pooled sensitivity was 0.77 (95% CI 0.67–0.85) and the pooled specificity was 0.77 (95% CI 0.71–0.82). The results of subgroup of patients without undergoing surgery (AUC =0.86, Youden index =0.65) and the results of subgroup of patients in ICU (AUC =0.89, Youden index =0.67) were reliable.

Conclusion

The reliability of the PVI is limited, but the PVI can play an important role in bedside monitoring for mechanically ventilated patients who are not undergoing surgery. Patients who are expanded with colloid may be more suitable for PVI.

Electronic supplementary material

The online version of this article (10.1186/s12871-019-0744-4) contains supplementary material, which is available to authorized users.

Pulse pressure variation and pleth variability index as predictors of fluid responsiveness in patients undergoing spinal surgery in the prone position

Background

This study investigated the ability of pulse pressure variation (PPV) and pleth variability index (PVI) to predict fluid responsiveness of patients undergoing spinal surgery in the prone position.

Patients and methods

A total of 53 patients undergoing posterior lumbar spinal fusion in the prone position on a Jackson table were studied. PPV, PVI, and hemodynamic and respiratory variables were measured both before and after the administration of 6 mL/kg colloid in both the supine and prone positions. Fluid responsiveness was defined as a 15% or greater increase in stroke volume index, as assessed by esophageal Doppler monitor after fluid loading.

Results

In the supine position, 40 patients were responders. The areas under the receiver operating characteristic (ROC) curves for PPV and PVI were 0.783 [95% CI 0.648–0.884, P<0.001] and 0.814 (95% CI 0.684–0.908, P<0.001), respectively. The optimal cut-off values of PPV and PVI were 10% (sensitivity 75%, specificity 62%) and 8% (sensitivity 78%, specificity 77%), respectively. In the prone position, 27 patients were responders. The areas under the ROC curves for PPV and PVI were 0.781 (95% CI 0.646–0.883, P<0.001) and 0.756 (95% CI 0.618–0.863, P<0.001), respectively. The optimal cut-off values of PPV and PVI were 7% (sensitivity 82%, specificity 62%) and 8% (sensitivity 67%, specificity 69%), respectively.

Conclusion

Both PPV and PVI were able to predict fluid responsiveness; their predictive abilities were maintained in the prone position.

Accuracy of pleth variability index compared with inferior vena cava diameter to predict fluid responsiveness in mechanically ventilated patients

In the intensive care unit (ICU), stable hemodynamics are very important. Hemodynamic intervention is often effective against multiple organ failure, such as in tissue hypoxia and shock. The administration of intravenous fluids is the first step in regulating tissue perfusion.The main objective of this study is to compare the performance between 2 methods namely pleth variability index (PVI) and IVC distensibily index (dIVC).In this study, the hemodynamic measurements were performed before and after passive leg raising (PLR). Measurements were obtained, including, PVI, dIVC, and cardiac index (CI). Both CI and dIVC measurements were evaluated by transesophageal probe and convex probe respectively. The dIVC measurements were taken using M-mode, 2 cm from junction between the right atrium and the inferior vena cava. The PVI was measured by Masimo Radical-7 monitor, Masimo.A total of 72 patients were included. The dIVC at a threshold value of >23.8% provided 80% sensitivity and 87.5% specificity to predict fluid responsiveness and was statistically significant (P < .001), with an AUC 0.928 (0.842-0.975). The PVI at a threshold value of >14% provided 95% sensitivity and 81.2% specificity to predict fluid responsiveness and was statistically significant (P < .001), with an AUC 0.939 (0.857-0.982).Both PVI and dIVC can be used as a noninvasive method that can be easily applied at the bedside in determining fluid responsiveness in all patients with mechanical ventilation in intensive care.

What is the impact of the fluid challenge technique on diagnosis of fluid responsiveness? A systematic review and meta-analysis

Background

The fluid challenge is considered the gold standard for diagnosis of fluid responsiveness. The objective of this study was to describe the fluid challenge techniques reported in fluid responsiveness studies and to assess the difference in the proportion of ‘responders,’ (PR) depending on the type of fluid, volume, duration of infusion and timing of assessment.

Methods

Searches of MEDLINE and Embase were performed for studies using the fluid challenge as a test of cardiac preload with a description of the technique, a reported definition of fluid responsiveness and PR. The primary outcome was the mean PR, depending on volume of fluid, type of fluids, rate of infusion and time of assessment.

Results

A total of 85 studies (3601 patients) were included in the analysis. The PR were 54.4% (95% CI 46.9–62.7) where <500 ml was administered, 57.2% (95% CI 52.9–61.0) where 500 ml was administered and 60.5% (95% CI 35.9–79.2) where >500 ml was administered (p = 0.71). The PR was not affected by type of fluid. The PR was similar among patients administered a fluid challenge for <15 minutes (59.2%, 95% CI 54.2–64.1) and for 15–30 minutes (57.7%, 95% CI 52.4–62.4, p = 1). Where the infusion time was ≥30 minutes, there was a lower PR of 49.9% (95% CI 45.6–54, p = 0.04). Response was assessed at the end of fluid challenge, between 1 and 10 minutes, and >10 minutes after the fluid challenge. The proportions of responders were 53.9%, 57.7% and 52.3%, respectively (p = 0.47).

Conclusions

The PR decreases with a long infusion time. A standard technique for fluid challenge is desirable.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-017-1796-9) contains supplementary material, which is available to authorized users.

Agreement between Pleth Variability Index and oesophageal Doppler to predict fluid responsiveness

BACKGROUND

Optimisation of stroke volume using oesophageal Doppler is an established technique to guide intraoperative fluid therapy. The method has practical limitations and therefore alternative indices of fluid responsiveness, such as ventilator-induced variation in the pulse oximetric signal (Pleth Variability Index (PVI)) could be considered. We hypothesised that both methods predict fluid responsiveness in a similar way.

METHODS

Seventy-five patients scheduled for open major abdominal surgery were randomised to fluid optimisation using fluid bolus algorithms based on either PVI (n = 35) or Doppler (n = 39). All patients were monitored with both methods; the non-guiding method was blind. Primary endpoint was the concordance between the methods to predict fluid responsiveness. We also analysed the ability of each method to predict a stroke volume increase ≥ 10% after a fluid bolus, as well as the accumulated intraoperative bolus fluid volume.

RESULTS

PVI indicated a need for fluid in one-third of the situations when Doppler did so, Cohen's kappa = 0.03. A fluid bolus indicated by the PVI algorithm increased stroke volume by ≥ 10% in half the situations. The same was found for the Doppler algorithm. The mean total bolus volume given was 878 ml when the fluid management was governed by PVI compared to 826 ml with Doppler (P = 0.71).

CONCLUSION

PVI- and Doppler-based stroke volume optimisations agreed poorly, which did not affect the amount of fluid administered. None of the algorithms showed a good ability to predict fluid responsiveness. Our results do not support the fluid responsiveness concept.

Accuracy of pleth variability index to predict fluid responsiveness in mechanically ventilated patients: a systematic review and meta-analysis

To systemically evaluate the accuracy of pleth variability index to predict fluid responsiveness in mechanically ventilated patients. A literature search of PUBMED, OVID, CBM, CNKI and Wanfang Data for clinical studies in which the accuracy of pleth variability index to predict fluid responsiveness was performed (last update 5 April 2015). Related journals were also searched manually. Two reviewers independently assessed trial quality according to the modified QUADAS items. Heterogeneous studies and meta-analysis were conducted by Meta-Disc 1.4 software. A subgroup analysis in the operating room (OR) and in intensive care unit (ICU) was also performed. Differences between subgroups were analyzed using the interaction test. A total of 18 studies involving 665 subjects were included. The pooled area under the receiver operating characteristic curve (AUC) to predict fluid responsiveness in mechanically ventilated patients was 0.88 [95 % confidence interval (CI) 0.84-0.91]. The pooled sensitivity and specificity were 0.73 (95 % CI 0.68-0.78) and 0.82 (95 % CI 0.77-0.86), respectively. No heterogeneity was found within studies nor between studies. And there was no significant heterogeneity within each subgroup. No statistical differences were found between OR subgroup and ICU subgroup in the AUC [0.89 (95 % CI 0.85-0.92) versus 0.90 (95 % CI 0.82-0.94); P = 0.97], and in the specificity [0.84 (95 % CI 0.75-0.86) vs. 0.84 (95 % CI 0.75-0.91); P = 1.00]. Sensitivity was higher in the OR subgroup than the ICU subgroup [0.84 (95 % CI 0.78-0.88) vs. 0.56 (95 % CI 0.47-0.64); P = 0.00004]. The pleth variability index has a reasonable ability to predict fluid responsiveness.