Mini-fluid Challenge Research Articles

Decrease in pulse pressure and stroke volume variations after mini-fluid challenge accurately predicts fluid responsiveness

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

Mini-fluid challenge predicts fluid responsiveness during spontaneous breathing under spinal anaesthesia: An observational study.

The ability to predict fluid responsiveness in spontaneously breathing patients under spinal anaesthesia is desirable. The objective of this study was to test whether variations in stroke volume (SV) in response to a fixed mini-fluid challenge (ΔSV100) measured by thoracic impedance cardiography (ICG) can predict fluid responsiveness in spontaneously breathing patients under spinal anaesthesia. A prospective observational study. Anaesthesiology department in a university hospital. Seventy-three patients monitored by ICG during surgery under spinal anaesthesia. Patients received a 100 ml fluid challenge followed by volume expansion with 500 ml of crystalloid. Haemodynamic variables and bioimpedance indices [blood pressure, SV, cardiac output (CO)] were measured before and after fluid challenge and before and after volume expansion. Responders were defined as those with >15% increase in SV after volume expansion. SV increased by at least 15% in 27 (37%) of the 73 patients. ΔSV100 predicted fluid responsiveness with an area under the receiver operating characteristic (AUC) curve of 0.93 [95% confidence interval (95% CI) 0.8 to 0.97, P < 0.001]. The cut-off was 7% and a grey zone ranging between 3 and 8% was observed in up to 14% of patients. SV baseline was a poor predictor of fluid responsiveness [AUC of 0.69 (95% CI 0.57 to 0.79, P = 0.002)]. ΔSV100 greater than 7% accurately predicted fluid responsiveness during surgery with a grey zone ranging between 3 and 8%.

Changes in end-tidal CO2 could predict fluid responsiveness in the passive leg raising test but not in the mini-fluid challenge test: A prospective and observational study

ObjectiveThe objective is to explore the value of end-tidal carbon dioxide (ETCO2) in replacing cardiac index for evaluating fluid responsiveness during the passive leg raising (PLR) test and mini-fluid challenge (mini-FC). MethodsPatients experiencing septic shock and who were on mechanical ventilation in an intensive care unit were divided into responder and nonresponder groups according to whether their cardiac index increased by more than 10% after the FC. Before and after those tests, the changes in ETCO2, central venous pressure, heart rate, mean arterial pressure, pulse pressure, and cardiac output were recorded. ResultsOf the 48 patients in the study, 34 had fluid responsiveness according to the changes in cardiac output or stroke volume. The ΔCI and ΔETCO2 in the responder group were larger than the changes in the nonresponder group during the PLR test (1.1 ± 0.7 vs 0.2 ± 0.4 L/min per square meter, 3.0 ± 3.0 vs 0.5 ± 2.5 mm Hg; P < .05) but not during mini-FC. ΔETCO2 greater than or equal to 5% during the PLR test predicted fluid responsiveness with 93.4% specificity and 75.8% sensitivity in a receiver operating characteristic curve. The area under the curve was 0.849 (95% confidence interval, 0.739-0.930). ΔETCO2 greater than or equal to 3% during the mini-FC predicted fluid responsiveness with 93.4% specificity and 33.3% sensitivity in a receiver operating characteristic curve, and the area under the curve was 0.781 (95% confidence interval, 0.646-0.915). ConclusionsThe changes in ETCO2 may predict fluid responsiveness during the PLR test in patients with septic shock, but similar results were not found with the mini-FC.

Use of systolic pressure variation to predict the cardiovascular response to mini-fluid challenge in anaesthetised dogs

Systolic pressure variation (SPV), the maximum variation in systolic pressure values following a single positive pressure breath delivered by controlled mechanical ventilation (CMV), is highly correlated with volaemia in dogs. The aim of this study was to determine an SPV value that would indicate when fluid administration would be beneficial in clinical practice. Twenty-six client-owned dogs were anaesthetised, following which CMV with a peak inspiratory pressure (PIP) of 8 cmH2O was applied. After SPV measurement and recording of heart rate (HR) and blood pressure (BP), 3 mL/kg fluid were administered, then HR and BP were recorded again. Dogs exhibiting a 10% decrease in HR and/or an increase in BP were defined as responders, and their SPV pre-bolus was analysed retrospectively.SPV values > 4 mmHg or >4.5% predicted haemodynamic improvement in dogs with normal cardiovascular function, with a sensitivity of 90% and a specificity of 87%. The area under the curve receiver operating characteristic value for SPV was 0.931 mmHg (95% confidence interval, CI, 0.76–0.99 mmHg) and 0.944% (95% CI 0.78–0.99%). It is proposed that SPV values > 4.5% in dogs with a normal cardiovascular function, anaesthetised with isoflurane in oxygen and air, and on CMV (PIP 8 cmH2O), can be used to predict a cardiovascular response (>10% increase in mean arterial BP and/or >10% decrease in heart rate).

Evaluation of hydration status calculated from differences in venous and capillary plasma dilution during stepwise crystalloid infusions: A randomized crossover study in healthy volunteers

Background and objectiveA mini volume loading test (mVLT) was proposed for estimating hydration status and interstitial fluid accumulation during stepwise infusion of crystalloids. The method is based on both the transcapillary reflux model and the hypothesis that when subjects are dehydrated, venous plasma dilution induced by a fluid challenge is higher than in the capillaries, and that difference is diminished when the fluid challenge is given to more hydrated individuals. Our objective was to test that hypothesis by evaluating the veno-capillary dilution difference during mVLT in subjects with different hydration status. Materials and methodsIn a prospective randomized crossover study, three mini fluid challenges were given to 12 healthy volunteers on two occasions. The subjects were either dehydrated or hydrated before the experiments. ResultsIn dehydrated subjects only, capillary plasma dilution was significantly lower than venous (P=0.015, 0.005 and 0.006) after each mini fluid challenge. ConclusionsVeno-capillary dilution difference during mVLT depends on the hydration status. The mVLT method could possibly discriminate between the different states of hydration.

Closed-Loop Systems in Anesthesia

Closed-Loop Systems in Anesthesia

Mini-fluid challenge: how much fluid and what parameter to use?

The mini-fluid challenge is a widely used strategy to manage fluid loading in the ICU and OR. Although it might be a rational strategy, data on the mini-fluid challenge and its reliability are very limited. We investigated the value of changes in pulse contour cardiac output as a result of a mini-fluid challenge of 50 and 100 ml to predict fluid loading responsiveness.

Goal Directed Fluid Therapy Revised: Indirect Monitoring of Interstitial Fluid Accumulation During Mini Fluid Challenges with Crystalloids

Goal directed fluid therapy (GDT) implies administration of fluid boluses with the aim of optimizing cardiac performance. There is a major concern that maximization of cardiovascular performance can be achieved in expense of deterioration in body hydration processes. Also, these methods require semi invasive devices. However, monitoring of the whole body hydration status and interstitial fluid accumulation during fluid loading is not possible in everyday clinical practice. A new method, minimum Volume Loading Test (mVLT), uses evaluation of plasma dilution efficacy in small fluid boluses (2.5 - 5.0 ml kg -1 ) of isoosmotic crystalloid solutions followed by 5 min periods without fluids. The inva- sively measured arterial and venous hemoglobins, and simultaneous non-invasively measured hemoglobin (SpHb TM from Radical-7, Masimo inc., Irvine, USA) are used for estimation of plasma dilution which serves as an indication of plasma volume expansion. The objective of this paper was to discuss plasmadilution as a target parameter for goal directed therapy. Could plasma di- lution also indicate a degree of interstitial fluid accumulation?

Case Scenario

Case Scenario

“Let's Give Some Fluid and See What Happens”versus the “Mini-fluid Challenge”

“Let's Give Some Fluid and See What Happens”<i>versus</i> the “Mini-fluid Challenge”

Subject index

The emergency department (ED) is frequently the doorway to the intensive care unit (ICU) for a significant number of critically ill patients presenting to the hospital. Hemodynamic monitoring (HDM) which is a key component in the effective management of the critically ill patient presenting to the ED, is primarily concerned with assessing the performance of the cardiovascular system and determining the correct therapeutic intervention to optimise end-organ oxygen delivery. The spectrum of hemodynamic monitoring ranges from simple clinical assessment and routine bedside monitoring to point of care ultrasonography and various invasive monitoring devices. The clinician must be aware of the range of available techniques, methods, interventions and technological advances as well as possess a sound approach to basic hemodynamic monitoring prior to selecting the optimal modality. This article comprises an in depth discussion of an approach to hemodynamic monitoring techniques and principles as well as methods of predicting fluid responsiveness as it applies to the ED clinician. We review the role, applicability and validity of various methods and techniques that include; clinical assessment, passive leg raising, blood pressure, finger based monitoring devices, the mini-fluid challenge, the end-expiratory occlusion test, central venous pressure monitoring, the pulmonary artery catheter, ultrasonography, bioreactance and other modern invasive hemodynamic monitoring devices.

Mini-fluid Challenge as a Predictor of Fluid Response for Pneumoperitoneum Patient

Mini-fluid Challenge as a Predictor of Fluid Response for Pneumoperitoneum Patient