Volume Responsiveness In Patients Research Articles

Influencing factors and countermeasures of pulse pressure variation in predicting volume responsiveness in patients with acute respiratory distress syndrome

脉压变异率（PPV）作为心肺交互的产物，是预测容量反应性的动态指标，但PPV预测急性呼吸窘迫综合征患者容量反应性受到诸多因素影响，如小潮气量通气、自主呼吸、腹内高压，此时可通过改变PPV阈值、潮气量挑战、叹息试验等方法提高其预测准确性；当PPV预测容量反应性准确性受到呼吸系统顺应性降低或右心功能不全影响时，则需要通过被动抬腿试验和呼气末阻断试验才能准确预测容量反应性。.

The diagnostic accuracy of inferior vena cava respiratory variation in predicting volume responsiveness in patients under different breathing status following abdominal surgery

BackgroundThe validation of inferior vena cava (IVC) respiratory variation for predicting volume responsiveness is still under debate, especially in spontaneously breathing patients. The present study aims to verify the effectiveness and accuracy of IVC variability for volume assessment in the patients after abdominal surgery under artificially or spontaneously breathing.MethodsA total of fifty-six patients after abdominal surgeries in the anesthesia intensive care unit ward were included. All patients received ultrasonographic examination before and after the fluid challenge of 5 ml/kg crystalloid within 15 min. The same measurements were performed when the patients were extubated. The IVC diameter, blood flow velocity–time integral of the left ventricular outflow tract, and cardiac output (CO) were recorded. Responders were defined as an increment in CO of 15% or more from baseline.ResultsThere were 33 (58.9%) mechanically ventilated patients and 22 (39.3%) spontaneously breathing patients responding to fluid resuscitation, respectively. The area under the curve was 0.80 (95% CI: 0.68–0.90) for the IVC dimeter variation (cIVC1) in mechanically ventilated patients, 0.87 (95% CI: 0.75–0.94) for the collapsibility of IVC (cIVC2), and 0.85 (95% CI: 0.73–0.93) for the minimum IVC diameter (IVCmin) in spontaneously breathing patients. The optimal cutoff value was 15.32% for cIVC1, 30.25% for cIVC2, and 1.14 cm for IVCmin. Furthermore, the gray zone for cIVC2 was 30.72 to 38.32% and included 23.2% of spontaneously breathing patients, while 17.01 to 25.93% for cIVC1 comprising 44.6% of mechanically ventilated patients. Multivariable logistic regression analysis indicated that cIVC was an independent predictor of volume assessment for patients after surgery irrespective of breathing modes.ConclusionIVC respiratory variation is validated in predicting patients' volume responsiveness after abdominal surgery irrespective of the respiratory modes. However, cIVC or IVCmin in spontaneously breathing patients was superior to cIVC in mechanically ventilated patients in terms of clinical utility, with few subjects in the gray zone for the volume responsiveness appraisal.Trial registrationChiCTR-INR-17013093. Initial registration date was 24/10/2017.

End-tidal carbon dioxide partial pressure to assess the value of passive leg-raising test in predicting volume responsiveness in patients with septic shock

To investigate the value of partial pressure of end-tidal carbon dioxide (PETCO2) combined with passive leg raising test (PLR) in predicting volume responsiveness in patients with septic shock. A total of 43 patients with septic shock admitted to the second department of critical care medicine, People's Hospital of Xinjiang Uygur Autonomous Region from December 2019 to June 2021 were selected as the research subjects. PETCO2, cardiac index (CI), stroke volume variation (SVV), mean arterial pressure (MAP) and other hemodynamic indexes were monitored before and after PLR and volume stress test (VE). Subjects were grouped according to the CI variation rate (ΔCI) after VE test. Patients with ΔCI ≥ 15% were the responding group, and patients with ΔCI < 15% were the non-responding group. The receiver operator characteristic curve (ROC curve) was drawn to analyze the evaluation value of the change in PETCO2 after PLR on the evaluation value of fluid responsiveness. Among the 43 patients, 22 cases were in the responding group, accounting for 51.2%; 21 cases were in the non-responding group, accounting for 48.8%. After the PLR test, the change values of MAP, SVV, CI and PETCO2 in the responding group were higher than those in the non-responding group, and the differences were statistically significant [MAP (mmHg): 3.8±2.1 vs. 1.4±2.0, SVV (%): -5.3±2.5 vs. 2.7±2.0, CI (mL×s-1×m-2): 0.48±0.13 vs. 0.14±0.18, PETCO2 (mmHg): 3.4±1.8 vs. 1.1±1.0, all P < 0.05, 1 mmHg ≈ 0.133 kPa]. After the VE test, the changes of HR, MAP, SVV, CI and PETCO2 in the responding group were higher than those in the non-responding group [HR (times/min): -8.3±2.8 vs. -2.3±3.7, MAP (mmHg): 3.8±2.4 vs. 1.2±1.7, SVV (%): -6.3±3.1 vs. -3.3±2.0, CI (mL×s-1×m-2): 0.51±0.14 vs. 0.16±0.12, PETCO2 (mmHg): 3.3±1.2 vs. 1.3±1.1, all P < 0.05]. The area under the ROC curve (AUC) of the change in PETCO2 before and after the PLR test (ΔPETCO2 PLR) for evaluating fluid responsiveness was 0.881. When the critical value was 5.9%, the sensitivity was 76.7%, the specificity was 89.5%, and the correct index was 0.68; the AUC for SVV baseline assessment of fluid responsiveness was 0.835, and when the cut-off value was 12.8%, the sensitivity was 84.6%, the specificity was 80.0%, and the correct index was 0.65. The predictive value of ΔPETCO2 was not lower than the SVV baseline. After the PLR test, the change of PETCO2 can be used as a non-invasive, simple, safe and reliable indicator for predicting the volume responsiveness of patients with septic shock.

Application value of bedside ultrasound for assessing volume responsiveness in patients with septic shock

Background/Aim. Septic shock is a serious complication that can occur as consequence of infection. As the effective circulating blood volume is of vital importance in these cases, it is very important to keep track of this parameter constantly. The aim of this study was to explore the application value of bedside ultrasound for assessing volume responsiveness in patients with septic shock. Methods. A total of 102 patients with septic shock were selected. The volume load (VL) test was performed, and based on the results of the test, the patients were divided into the response group that had an increase in stroke volume (?SV ) ? 15% and non-response group (?SV &lt; 15%). Hemodynamic parameters were compared before and after the test. The correlation between ?SV and each hemodynamic index was explored by Pearson?s analysis. The receiver operating characteristic (ROC) curve was plotted. Results. There were 54 patients in response group and 48 patients in non-response group. Before VL test, retro-hepatic inferior vena cava (IVC) distensibility index (?IVC1), respiratory variation in IVC index (?IVC2), respiratory variation in aortic blood flow peak velocity index (?VpeakAO), respiratory variation in brachial artery blood flow peak velocity index (?VpeakBA) and respiratory variation in common femoral artery blood flow peak velocity index (?VpeakCFA) were all higher in response group than those in non-response group (p &lt; 0.05), while heart rate (HR), mean arterial pressure (MAP) and central venous pressure (CVP) were similar (p &gt; 0.05). After VL test, response group had significantly decreased HR, ?IVC1, ?IVC2, ?VpeakAO, ?VpeakBA and ?VpeakCFA, and increased MAP and CVP (p &lt; 0.05), while non-response group had significantly decreased CVP (p &lt; 0.05) and no significant changes in other indices. ?IVC1, ?IVC2, ?VpeakAO, ?VpeakBA and ?VpeakCFA significantly correlated with ?SV ( r= 0.589, r = 0.647, r = 0.697, r = 0.621, r = 0.766, p &lt; 0.05), but there was no correlation between CVP and ?SV (r = -0.345, p &gt; 0.05). The areas under the curves of ?IVC1, ?IVC2, ?VpeakAO, ?VpeakBA and ?VpeakCFA for predicting volume responsiveness were 0.839, 0.858, 0.878, 0.916 and 0.921, respectively, which were significantly larger than that of CVP (0.691), indicating higher sensitivity and specificity. Conclusion. Bedside ultrasound monitoring of ?IVC, ?VpeakAO, ?VpeakBA and ?VpeakCFA can better assess the volume responsiveness in patients with septic shock.

Clinical value of point of care ultrasound on cardiac output and volume responsiveness in patients with septic shock

To assess the value of point of care ultrasound on cardiac output (CO) and volume responsiveness in patients with septic shock. Twenty-four mechanical ventilation patients with septic shock who needed pulse-indicated continuous cardiac output (PiCCO) monitoring in the department of critical care medicine of Zhengzhou University People's Hospital, Henan Provincial People's Hospital from November 25, 2020 to April 30, 2021 were selected as the subjects, the patient's basic information and laboratory test results were recorded. PiCCO was used as standard to monitor CO and stroke volume variability (SVV) at 0, 2, 6, 12, 24 and 48 hours. At the same time, point of care transthoracic echocardiography (TTE) was used to measure velocity time integral (VTI) and inferior vena cava diameter (dIVC), the CO, VTI variation rate (ΔVTI) and dIVC variation rate (ΔdIVC) were calculated. Then, using the value monitored by PiCCO as the standard, the consistency and correlation analysis were carried out between point of care ultrasound with PiCCO. Twenty-two out of 24 patients obtained satisfactory ultrasound Doppler images, the heart rate (HR), mean arterial pressure (MAP) and body temperature of the enrolled patients were consistent with the pathophysiological characteristics of septic shock. With the extension of treatment time, HR and CO both gradually decreased, and MAP gradually increased, reaching a peak or trough at 48 hours after admission. The difference were statistically significant compared with the time of admission [HR (bpm): 90.36±15.35 vs. 116.82±19.82, MAP (mmHg, 1 mmHg = 0.133 kPa): 87.82±11.06 vs. 58.82±9.85, CO (L/min): 4.80±0.56 vs. 6.78±1.31, all P < 0.05]. The CO obtained by PiCCO and point of care ultrasound had good agreement [5.36 (4.78, 6.33) L/min and 5.21 (4.88, 6.35) L/min, respectively], the average difference value at each time point was (-0.02±0.69) L/min, the 95% agreement limit range was -1.35-1.34, and there was a high degree of correlation (rs = 0.800, P < 0.001); The SVV by PiCCO and the ΔdIVC by point of care ultrasound were in good agreement [18.00% (14.00%, 24.00%) and 21.00% (14.00%, 25.75%), respectively], the average difference value at the time point was (-3.16±6.89)%, the 95% agreement limit range was -16.89-10.54, and there was a moderate correlation (rs = 0.702, P < 0.001); The SVV by PiCCO and the ΔVTI by point of care ultrasound were in good agreement [18.00% (14.00%, 24.00%) and 16.00% (11.25%, 20.75%), respectively], the average difference value at each time point was (13.03±14.75)%, and the 95% agreement limit range was 1.72-27.78, and there was a high correlation (rs = 0.918, P < 0.001). Point of care ultrasound can accurately assess CO and volume responsiveness of patients with septic shock, and the ΔVTI is better than the ΔdIVC in assessing volume responsiveness.

Accuracy assessment of noninvasive cardiac output monitoring in the hemodynamic monitoring in critically ill patients.

The consistency of cardiac output (CO) measured by noninvasive cardiac output monitoring (NICOM), pulse index continuous cardiac output (PiCCO), and ultrasound in the hemodynamic monitoring of critically ill patients was studied. Using the NICOM built-in passive leg raising (PLR) test, stroke volume index variation (∆SVI) was calculated and was used to predict volume responsiveness in patients with circulatory shock (excluding cardiogenic shock). Critically ill patients requiring hemodynamic monitoring were admitted during the study period. The CO of each included patient under hemodynamic monitoring was measured by NICOM plus PiCCO or ultrasound, and the consistency of the measured COs was analyzed. By the NICOM built-in PLR test, ∆SVI was calculated and was used to predict volume responsiveness. The CO of 58 patients was measured by NICOM and ultrasound, and the COs measured by these two methods were consistent. The CO of 40 patients was measured by NICOM and PiCCO, and the COs measured by these two methods were consistent. The volume responsiveness of all 98 patients was assessed by the NICOM built-in PLR test. A total of 60 patients had ∆SVI >10%, so they underwent the fluid challenge. Among them, 43 patients were positive by both the NICOM built-in PLR and fluid challenge. When using ∆SVI to predict volume responsiveness in patients with circulatory shock (excluding cardiogenic shock), the area under the receiver operating characteristic curve was 0.754 (95% confidence interval, 0.626-0.856), and the cut-off value was 18% (sensitivity: 88.37%, specificity: 52.94%), indicating that ∆SVI has value in predicting the volume responsiveness of patients with noncardiogenic circulatory shock. NICOM had good consistency with ultrasound and PiCCO in the hemodynamic monitoring of critically ill patients and can be for hemodynamic monitoring and evaluation in critically ill patients. The ∆SVI obtained by the NICOM built-in PLR test has certain clinical value in predicting the volume responsiveness of patients with circulatory shock (excluding cardiac shock) and provides a method for evaluating the volume responsiveness of critically ill patients.

Passive leg raising combined with echocardiography could evaluate volume responsiveness in patients with septic shock

To assess the value of passive leg raising (PLR) combined with echocardiography in predicting volume responsiveness in patients with septic shock. Thirty septic shock patients with spontaneous respiration admitted to intensive care unit (ICU) of Tianjin First Center Hospital from July 2016 to August 2018 were enrolled. PLR and volume expansion (VE) were performed successively. The hemodynamic parameters including left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV), stroke volume (SV) and left ventricular ejection fraction (LVEF) before PLR (baseline level), after PLR, immediately after VE were examined by echocardiography, and the central venous pressure (CVP) was monitored. The patients with increase in SV after VE (ΔSV) ≥ 15% were served as reaction group, while ΔSV < 15% were served as non-reaction group. The changes in LVEDV, LVESV, SV, LVEF and CVP at baseline level, after PLR and after VE were compared between the two groups. Pearson correlation method was used to analyze the correlation between ΔSV, increase in LVEF (ΔLVEF) after PLR and ΔSV, and ΔLVEF after VE. Receiver operating characteristic (ROC) curve was plotted to evaluate the predictive value of ΔSV and ΔLVEF after PLR for volume responsiveness. PLR and VE were successfully performed in 30 patients, of which 23 patients (76.7%) were enrolled in the reaction group, and 7 patients (23.3%) in the non-reaction group. Compared with baseline levels, LVEDV, SV, and LVEF in the reaction group were significantly increased after PLR [LVEDV (mL): 83.5±9.6 vs. 77.1±6.2, SV (mL): 48.5±5.6 vs. 43.2±4.9, LVEF: 0.58±0.04 vs. 0.56±0.06, all P < 0.05], and CVP was significantly increased after VE [cmH2O (1 cmH2O = 0.098 kPa): 7.4±3.3 vs. 4.6±0.7, P < 0.01], however, there was no significant change in LVESV. In the non-reaction group, SV and LVEF were significantly increased after PLR as compared with those at baseline levels [SV (mL): 42.7±3.7 vs. 40.6±3.1, LVEF: 0.52±0.05 vs. 0.50±0.05, both P < 0.05], while LVEDV and CVP were significantly increased after VE as compared with those at baseline levels [LVEDV (mL): 84.4±4.1 vs. 80.6±5.9, CVP (cmH2O): 10.6±3.5 vs. 7.6±0.5, both P < 0.05], however, there was no significant change in LVESV. Pearson correlation analysis showed that ΔSV and ΔLVEF after PLR were positively correlated with ΔSV and ΔLVEF after VE (r1 = 0.86, r2 = 0.65, both P < 0.01). ROC curve analysis showed that the area under ROC curve (AUC) of PLR-induced ΔSV and ΔLVEF for predicting volume responsiveness was 0.85 and 0.66 respectively. When the cut-off value of ΔSV after PLR was 10.6%, the sensitivity was 78.2%, the specificity was 82.3%; when the cut-off value of ΔLVEF after PLR was 3.6%, the sensitivity was 78.2%, and the specificity was 73.2%. ΔSV and ΔLVEF measured by PLR combined with echocardiography can be used to evaluate the volume responsiveness in patients with septic shock and can guide fluid therapy.

Machine learning for the prediction of volume responsiveness in patients with oliguric acute kidney injury in critical care

Background and objectivesExcess fluid balance in acute kidney injury (AKI) may be harmful, and conversely, some patients may respond to fluid challenges. This study aimed to develop a prediction model that can be used to differentiate between volume-responsive (VR) and volume-unresponsive (VU) AKI.MethodsAKI patients with urine output < 0.5 ml/kg/h for the first 6 h after ICU admission and fluid intake > 5 l in the following 6 h in the US-based critical care database (Medical Information Mart for Intensive Care (MIMIC-III)) were considered. Patients who received diuretics and renal replacement on day 1 were excluded. Two predictive models, using either machine learning extreme gradient boosting (XGBoost) or logistic regression, were developed to predict urine output > 0.65 ml/kg/h during 18 h succeeding the initial 6 h for assessing oliguria. Established models were assessed by using out-of-sample validation. The whole sample was split into training and testing samples by the ratio of 3:1.Main resultsOf the 6682 patients included in the analysis, 2456 (36.8%) patients were volume responsive with an increase in urine output after receiving > 5 l fluid. Urinary creatinine, blood urea nitrogen (BUN), age, and albumin were the important predictors of VR. The machine learning XGBoost model outperformed the traditional logistic regression model in differentiating between the VR and VU groups (AU-ROC, 0.860; 95% CI, 0.842 to 0.878 vs. 0.728; 95% CI 0.703 to 0.753, respectively).ConclusionsThe XGBoost model was able to differentiate between patients who would and would not respond to fluid intake in urine output better than a traditional logistic regression model. This result suggests that machine learning techniques have the potential to improve the development and validation of predictive modeling in critical care research.

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.

A prospective clinical study of pleth variability index in prediction of volume responsiveness in patients with septic shock

To evaluate the role of pleth variability index ( PVI ) by passive leg raising ( PLR ) test in volume responsiveness and volume status prediction in patients with septic shock. A prospective randomized controlled trial ( RCT ) was conducted. Eighty-seven patients suffering from septic shock undergoing mechanical ventilation in Department of Critical Care Medicine of Subei People's Hospital from June 2012 to September 2014 were enrolled. The hemodynamic changes before and after PLR were monitored by pulse indicated continuous cardiac output ( PiCCO ) and PVI monitoring. Responsive group: positive fluid response was defined as an increase in cardiac index ( CI )≥10% after PLR. Unresponsive group: negative fluid response was defined as an increase in CI<10% after PLR. The hemodynamic parameters, including heart rate ( HR ), mean arterial pressure ( MAP ), central venous pressure ( CVP ), stroke volume variation ( SVV ), CI and PVI, and the changes in cardiac parameters (ΔHR, ΔMAP, ΔCVP, ΔSVV, ΔCI, and ΔPVI ) before and after PLR were determined. The relations between hemodynamic parameters and their changes with ΔCI were analyzed by the Pearson analysis. The role of the parameters for volume responsiveness prediction was evaluated by receiver operating characteristic ( ROC ) curves. 145 PLRs in 87 patients with septic shock were conducted, with 67 in responsive group and 78 in unresponsive group. There were no statistically significant differences in HR, MAP, CVP and CI before PLR between the responsive and unresponsive groups. SVV and PVI in responsive group were significantly higher than those in the unresponsive group [ SVV: ( 16.9±3.1 )% vs. ( 8.4±2.2 ) %, t = 9.078, P = 0.031; PVI: ( 20.6±4.3 )% vs. ( 11.1±3.2 )%, t = 19.189, P = 0.022 ]. There were no statistically significant differences in HR, MAP, CVP, SVV, and PVI after PLR between the responsive group and unresponsive group. CI in the responsive group was significantly higher than that in the unresponsive group ( mL×s(-1)×m(-2): 78.3±6.7 vs. 60.0±8.3, t = 2.902, P = 0.025 ). There were no statistically significant differences in ΔHR, ΔMAP, ΔCVP between responsive group and unresponsive group. ΔSVV, ΔCI and ΔPVI in responsive group were significantly higher than those in the unresponsive group [ ΔSVV: ( 4.6±1.5 )% vs. ( 1.8±0.9 )%, t = 11.187, P = 0.022; ΔCI ( mL×s(-1)×m(-2) ): 18.3±1.7 vs. 1.7±0.5, t = 3.696, P = 0.014; ΔPVI: ( 6.4±1.1 )% vs. ( 1.3±0.2 )%, t = 19.563, P = 0.013 ]. No significant correlation between HR, MAP or CVP before PLR and ΔCI was found. SVV ( r = 0.850, P = 0.015 ) and PVI ( r = 0.867, P = 0.001 ) before PLR were correlated with ΔCI. It was shown by ROC curve that the area under ROC curve ( AUC ) for SVV fluid responsiveness prediction was 0.948, and cut-off of SVV was 12.4%, the sensitivity was 85.4%, and specificity was 86.6%. The AUC for PVI fluid responsiveness prediction was 0.957, and cut-off was 14.8%, the sensitivity was 87.5%, and specificity was 84.8%. It was higher than other hemodynamic parameters ( HR, MAP, CVP ). PVI and SVV can better predict fluid responsiveness in mechanically ventilating patients with septic shock after PLR. PVI as a new continuous, noninvasive and functional hemodynamic parameter has the same accuracy as SVV.

Predication of volume responsiveness by brachial artery velocity change during passive leg raising

To evaluate whether or not brachial artery peak velocity (Vpeak-BA) induced by passive leg raising (PLR) may predict volume responsiveness. We prospectively studied 29 patients enrolled into our intensive care unit (ICU) with spontaneous breathing during mechanical ventilation. Through echocardiography we compared the changes of brachial artery peak velocity induced by passive leg raising (ΔVBA-PLR) and the changes of left ventricle outflow tract velocity-time integral after volume expansion (ΔVTI-VE). Also the sensitivity and specificity of ΔVpeak-BA were determined in predicting volume responsiveness. Among them, 15 responded to volume expansion and the rest 14 did not. ΔVBA-PLR and ΔVTI-VE were mutually correlated (R(2) = 0.378, P = 0.011). The sensitivity and specificity of ΔVpeak-BA ≥ 16% to predict volume responsiveness were 73% and 87% respectively. Brachial artery peak velocity induced by passive leg raising is a reliable indicator of predicting volume responsiveness in patients with spontaneous breathing.

Prediction of fluid responsiveness in patients admitted to the medical intensive care unit

PurposeAccurate prediction of fluid responsiveness is of importance in the treatment of patients admitted to the intensive care unit (ICU). We investigated whether physical examination, central venous pressure (CVP), central venous oxygen saturation (ScvO2), passive leg raising (PLR) test, and transpulmonary thermodilution (TPTD)–derived parameters can predict volume responsiveness in patients admitted to the ICU. Materials and MethodsIn this prospective study, structured clinical examination, measurement of CVP and ScvO2, a PLR test, and TPTD measurements were performed in 31 patients. A fluid challenge test was performed in 24 patients (fluid responsiveness was defined as a cardiac index [CI] increase of ≥15%). ResultsPhysical examination, CVP, ScvO2, the PLR test, and the TPTD-derived volumetric preload parameter global end-diastolic volume index showed poor prognostic capabilities regarding prediction of fluid responsiveness. Twenty-nine percent of patients were fluid responsive. There was a statistically significant correlation between the fluid challenge–induced increase in CI and changes in global end-diastolic volume index (r = 0.666, P < .001). In only 17% of patients, CI did not increase after fluid loading. ConclusionsPrediction of fluid responsiveness is difficult using physical examination, CVP, ScvO2, PLR maneuver, or TPTD-derived variables in critically ill patients. A volume challenge test should be considered for the assessment of fluid responsiveness in critically ill patients admitted to the ICU.

312 Emergency Physician Accuracy in Estimating Volume Responsive Shock Using the “CURVES” Questionnaire

Excess fluid administration and inadequate or delayed fluid resuscitation carry increased morbidity and mortality. Intensive care unit studies have shown that approximately 50% of patients given fluid boluses were truly volume responsive when compared to dynamic changes in cardiac output or stroke volume. In ED patients with undifferentiated shock, emergency physician accuracy in estimating volume responsiveness when compared to dynamic changes in cardiac output or stroke volume is unknown. To assess emergency physician accuracy in estimating volume responsiveness in patients with shock. This is a pilot study analyzing patients from a prospective randomized controlled trial of fluid optimization in the ED (“EFFORT”-ED Flow-directed Fluid Optimization Resuscitation Trial; ClinicalTrials.gov ID: NCT01128413). The study is IRB approved with informed consent. Enrollment began in August, 2010 and continues at an urban, academic tertiary care medical center with 90,000 ED visits/year. Inclusion criteria are adults (≥ 18 years) with either of the following: hypotension (SBP ≤90 or mean arterial pressure ≤65) despite 20ml/kg fluids; vasopressor use; or lactate ≥ 2.5 mmol/L. Patients are randomized to receive IV fluids via 1 of 2 arms: 1) routine care per clinician discretion 2) fluid optimization with 500ml normal saline boluses if the cardiac index or stroke volume index increases ≥ 15% with passive leg raise testing (PLRT). Patients are monitored until ED departure or a maximum of 6 hours using continuous noninvasive cardiac output monitoring (Cheetah NICOM®). During this time, passive leg raise testing is performed immediately before and after each fluid bolus or at 30-minute intervals if on a locked or maintenance fluid rate. With each passive leg raise testing, a CURVES (CardiovascUlar Response and Volume Estimation in Shock) questionnaire is administered separately to attending and resident physicians caring for the patients. Clinicians are blinded to the results of the passive leg raise testing and NICOM® monitoring. The CURVES questionnaire is a newly developed 5-item survey for this study which queries clinicians for the patient's potential shock etiology and estimations of volume responsiveness at that point in time (ie, responsive or unresponsive to further fluid administration), intravascular volume status, and cardiac index. With each questionnaire, clinicians are given the current vital signs, total volume administered, urine output, and the option for bedside re-examination, lab review, or the use of any other modality used in their routine care (ie, ultrasound, CVP, Scv02). Descriptive statistical analysis was performed using Microsoft® Excel. 11/11 per protocol patients were analyzed. The median age was 58 years (range 20-90) with 27% female. A total of 79 passive leg raise testings and 118 CURVES were acquired. 50/79 (63.3%) passive leg raise testing demonstrated volume responsiveness changes in cardiac index or stroke volume index. Attending emergency physician accuracy in estimating volume responsiveness was 68% with a sensitivity of 89% and specificity of 32%. Resident accuracy was 41% with a sensitivity of 45% and specificity of 35%. This pilot study suggests that emergency physician accuracy in estimating volume responsiveness in the setting of shock is poor when compared to passive leg raise testing changes in cardiac index or stroke volume. Routine clinical estimations of volume responsiveness not guided by dynamic changes in cardiac index or stroke volume index may lead to inadequate or excess fluid administration. The impact of ED fluid administration guided by dynamic changes in cardiac index or stroke volume index on morbidity and mortality is unknown.

Passive leg raising predicts volume responsiveness in patients with severe sepsis and septic shock

To evaluate the role of passive leg raising (PLR) test in predicting volume responsiveness in severe sepsis and septic shock patients. Thirty severe sepsis and septic shock patients in intensive care unit (ICU) of Peking University Shenzhen Hospital were prospectively observed from February 2009 to January 2010. The hemodynamics including stroke volume (SV), cardiac output (CO) and systemic vascular resistance (SVR) were measured non invasively by ultrasonic cardiac output monitor (USCOM) device in the supine position, during PLR and after volume expansion (VE), and invasive arterial blood pressure and central venous pressure (CVP) were monitored consecutively. Responders were defined by the appearance of an increase in SV (ΔSV) ≥ 15% after VE. The role of PLR for predicting volume responsiveness was evaluated by receiver operating characteristic (ROC) curves. The CVP (cm H(2)O, 1 cm H(2)O=0.098 kPa) during PLR was increased compared with that at supine position in both responder group ( n =15) and non responder group ( n =15, 13.6 ± 6.6 vs. 12.1 ± 6.0, 11.9 ± 5.5 vs. 10.8 ± 5.2 , both P <0.01). ΔSV was higher in responder group than in non responder group during PLR [(16.6 ± 5.5)% vs. (3.8 ± 8.2)%, P=0.000].ΔSV during PLR was highly correlated to ΔSV after VE (r =0.681 , P =0.000).The area under the ROC curve (AUC) for PLR predicting volume responsiveness was 0.944 ± 0.039 ( P =0.000). The ΔSV>11% during PLR was found to predict volume responsiveness with a sensitivity of 86.7%, specificity of 93.3%, positive predictive value of 92.9% and negative predictive value of 87.5%. PLR can be used generally to predict volume responsiveness accurately in severe sepsis and septic shock patients, and it can be used to direct clinical practice.

Accuracy of stroke volume variation as a predictor of volume responsiveness in patients with raised intra-abdominal pressure

Dynamic predictors of fluid responsiveness such as stroke volume variation (SVV) are gaining popularity. Intra-abdominal hypertension (IAH) affects heart-lung interactions and may invalidate SVV as a preload indicator, as indeed suggested in a recent animal study [1]. We studied SVV in liver patients, who have a high incidence of raised intra-abdominal pressure (IAP).

The role of stroke volume variation in predicting the volume responsiveness of patients with severe sepsis and septic shock

Objective To assess the role of stroke volume variation (SVV) in predicting the volume responsiveness of mechanically ventilated patients with severe sepsis and septic shock. Method A total of 28 mechanically ventilated patients with severe sepsis and septic shock were admitted from January 2009 to March 2010. Every patient was treated with volume loading test. Cardiac index (CI), stroke volume index (SVI), systemic vascular resistance (SVR) and SVV were measured non-invasively by Ultrasonic Cardiac Output Monitor (USCOM) device.Patients with an increase in CI ＞ 12% and ＜ 12% after volume loading test were classified as responders and nonresponders, respectively. The comparisons between these two sorts of patients were assessed by using two sample Student' s t -test, and comparisons between changes before and after volume loading test were assessed by using a paired Student's t -test. The roles of SVV, central venous pressure (CVP) and the changes of CVP (△CVP) after fluid administration in predicting volume responsiveness were evaluated by receiver operating characteristic (ROC) curves. Results Before volume loading test, the SVV was higher in responders in comparison with non-responders [(18.2 ± 4.7)% vs. (12.7 ± 4.2)%, P = 0.003] and the CVP was not significantly different between two groups [(10.2±4.0) cmH2O vs. (10.8±4.8) cmH2O, P ＞0.05]. After volume loading test,the CVP was lower in responders [(2.9 ± 3.1 ) cmH2O vs. (5.3 ± 2.7) cmH2O, P = 0.003]. The areas under the ROC curves (AUC) were 0.836 (95% CI:0.680 ～ 0.992,P = 0.003),0.549 (95% CI:0.329 ～ 0.768,P = 0.662)and 0.762 (95% CI:0.570 ～ 0.953,P = 0.019)for SVV, CVP and △CVP, respectively. The 15.5% of SVV value had the 84.6% of sensitivity and 80% of specificity for prediction of volume responsiveness. Conclusions SVV can serve as a valid indicator of predicting volume responsiveness in mechanically ventilated patients with severe sepsis and septic shock and it is more reliable than conventional indicators such as CVP and/△CVP. Key words: Stroke volume variation; Severe sepsis and septic shock; Volume responsiveness; Central venous pressure; Volume challenge; Hemodynamic; Mechanical ventilation; Cardiac index

Pulse pressure variation and volume responsiveness during acutely increased pulmonary artery pressure: an experimental study

IntroductionWe found that pulse pressure variation (PPV) did not predict volume responsiveness in patients with increased pulmonary artery pressure. This study tests the hypothesis that PPV does not predict fluid responsiveness during an endotoxin-induced acute increase in pulmonary artery pressure and right ventricular loading.MethodsPigs were subjected to endotoxemia (0.4 μg/kg/hour lipopolysaccharide), followed by volume expansion, subsequent hemorrhage (20% of estimated blood volume), retransfusion, and additional stepwise volume loading until cardiac output did not increase further (n = 5). A separate control group (n = 7) was subjected to bleeding, retransfusion, and volume expansion without endotoxemia. Systemic hemodynamics were measured at baseline and after each intervention, and PPV was calculated offline. Prediction of fluid-challenge-induced stroke volume increase by PPV was analyzed using receiver operating characteristic (ROC) curves.ResultsSixty-eight volume challenges were performed in endotoxemic animals (22 before and 46 after hemorrhage), and 51 volume challenges in the controls. Endotoxin infusion resulted in an acute increase in pulmonary artery and central venous pressure and a decrease in stroke volume (all P < 0.05). In endotoxemia, 68% of volume challenges before hemorrhage increased the stroke volume by > 10%, but PPV did not predict fluid responsiveness (area under the ROC curve = 0.604, P = 0.461). After hemorrhage in endotoxemia, stroke volume increased in 48% and the predictive value of PPV improved (area under the ROC curve for PPV = 0.699, P = 0.021). In controls after hemorrhage, stroke volume increased in 67% of volume challenges and PPV was a predictor of fluid responsiveness (area under the ROC curve = 0.790, P = 0.001).ConclusionsFluid responsiveness cannot be predicted with PPV during acute pulmonary hypertension in porcine endotoxemia. Even following severe hemorrhage during endotoxemia, the predictive value of PPV is marginal.

Haemodynamic effects of plasma-expansion with hyperoncotic albumin in cirrhotic patients with renal failure: a prospective interventional study

BackgroundPatients with advanced cirrhosis of the liver typically display circulatory disturbance. Haemodynamic management may be critical for avoiding and treating functional renal failure in such patients. This study investigated the effects of plasma expansion with hyperoncotic albumin solution and the role of static haemodynamic parameters in predicting volume responsiveness in patients with advanced cirrhosis.MethodsPatients with advanced cirrhosis (Child B and C) of the liver receiving albumin substitution because of renal compromise were studied using trans-pulmonary thermodilution. Paired measurements before and after two infusions of 200 ml of 20% albumin per patient were recorded and standard haemodynamic parameters such as central venous pressure (CVP), mean arterial pressure (MAP), systemic vascular resistance index (SVRI), cardiac index (CI) and derived variables were assessed, including global end-diastolic blood volume index (GEDVI), a parameter that reflects central blood volumeResults100 measurements in 50 patients (33 m/17 w; age 56 years (± 8); Child-Pugh-score 12 (± 2), serum creatinine 256 μmol (± 150) were analyzed. Baseline values suggested decreased central blood volumes GEDVI = 675 ml/m2 (± 138) despite CVP within the normal range (11 mmHg (± 5). After infusion, GEDVI, CI and CVP increased (682 ml/m2 (± 128) vs. 744 ml/m2 (± 171), p < 0.001; 4.3 L/min/m2 (± 1.1) vs. 4.7 L/min/m2 (± 1.1), p < 0.001; 12 mmHg (± 6) vs. 14 mmHg (± 6), p < 0.001 respectively) and systemic vascular resistance decreased (1760 dyn s/cm5/m2 (± 1144) vs. 1490 dyn s/cm5/m2 (± 837); p < 0.001). Changes in GEDVI, but not CVP, correlated with changes in CI (r2 = 0.51; p < 0.001). To assess the value of static haemodynamic parameters at baseline in predicting an increase in CI of 10%, receiver-operating-characteristic curves were constructed. The areas under the curve were 0.766 (p < 0.001) for SVRI, 0.723 (p < 0.001) for CI, 0.652 (p = 0.010) for CVP and 0.616 (p = 0.050) for GEDVI.ConclusionIn a substantial proportion of patients with advanced cirrhosis, plasma expansion results in an increase in central blood volume. GEDVI but not CVP behaves as an indicator of cardiac preload, whereas high baseline SVRI is predictive of fluid responsiveness.

Prediction of volume responsiveness in critically ill patients with spontaneous breathing activity

Predicting volume responsiveness in patients with spontaneous breathing activity is a difficult challenge in the emergency room as well as in the intensive care unit because heart-lung interactions indices cannot be reliably used as they can be in mechanically ventilated patients fully adapted to their ventilator. The aim of this review is to summarize the different tools that have been proposed to predict the hemodynamic response to fluid infusion in the presence of spontaneous breathing activity. Clinical studies recently demonstrated that neither indicators of cardiac preload (filling pressures and end-diastolic ventricular dimensions) nor arterial pulse pressure respiratory variation was an accurate predictor of volume responsiveness in patients with spontaneous breathing activity with or without mechanical support. In contrast, performing a passive leg-raising test has been proved as valuable for this purpose. The passive leg-raising test is the only method that has been repeatedly shown to be reliable for predicting volume responsiveness in patients who experience spontaneous breathing. The appropriate utilization of this test requires a real-time assessment of its effects on systemic blood flow.

Radial Artery Pulse Pressure Variation Correlates With Brachial Artery Peak Velocity Variation in Ventilated Subjects When Measured by Internal Medicine Residents Using Hand-Carried Ultrasound Devices

Rapid prediction of the effect of volume expansion is crucial in unstable patients receiving mechanical ventilation. Both radial artery pulse pressure variation (DeltaPP) and change of aortic blood flow peak velocity are accurate predictors but may be impractical point-of-care tools. We sought to determine whether respiratory changes in the brachial artery blood flow velocity (DeltaVpeak-BA) as measured by internal medicine residents using a hand-carried ultrasound (HCU) device could provide an accurate corollary to DeltaPP in patients receiving mechanical ventilation. Thirty patients passively receiving volume-control ventilation with preexisting radial artery catheters were enrolled. The brachial artery Doppler signal was recorded and analyzed by blinded internal medicine residents using a HCU device. Simultaneous radial artery pulse wave and central venous pressure recordings (when available) were analyzed by a blinded critical care physician. A Doppler signal was obtained in all 30 subjects. The DeltaVpeak-BA correlated well with DeltaPP (r = 0.84) with excellent agreement (weighted kappa, 0.82) and limited intraobserver variability (2.8 +/- 2.8%) [mean +/- SD]. A DeltaVpeak-BA cutoff of 16% was highly predictive of DeltaPP > or = 13% (sensitivity, 91%; specificity, 95%). A poor correlation existed between the CVP and both DeltaVpeak-BA (r = - 0.21) and DeltaPP (r = - 0.16). The HCU Doppler assessment of the DeltaVpeak-BA as performed by internal medicine residents is a rapid, noninvasive bedside correlate to DeltaPP, and a DeltaVpeak-BA cutoff of 16% may prove useful as a point-of-care tool for the prediction of volume responsiveness in patients receiving mechanical ventilation.