Ability Of Pulse Pressure Variation Research Articles

Tidal volume challenge to predict preload responsiveness in patients with acute respiratory distress syndrome under prone position

BackgroundProne position is frequently used in patients with acute respiratory distress syndrome (ARDS), especially during the Coronavirus disease 2019 pandemic. Our study investigated the ability of pulse pressure variation (PPV) and its changes during a tidal volume challenge (TVC) to assess preload responsiveness in ARDS patients under prone position.MethodsThis was a prospective study conducted in a 25-bed intensive care unit at a university hospital. We included patients with ARDS under prone position, ventilated with 6 mL/kg tidal volume and monitored by a transpulmonary thermodilution device. We measured PPV and its changes during a TVC (ΔPPV TVC6–8) after increasing the tidal volume from 6 to 8 mL/kg for one minute. Changes in cardiac index (CI) during a Trendelenburg maneuver (ΔCITREND) and during end-expiratory occlusion (EEO) at 8 mL/kg tidal volume (ΔCI EEO8) were recorded. Preload responsiveness was defined by both ΔCITREND ≥ 8% and ΔCI EEO8 ≥ 5%. Preload unresponsiveness was defined by both ΔCITREND < 8% and ΔCI EEO8 < 5%.ResultsEighty-four sets of measurements were analyzed in 58 patients. Before prone positioning, the ratio of partial pressure of arterial oxygen to fraction of inspired oxygen was 104 ± 27 mmHg. At the inclusion time, patients were under prone position for 11 (2–14) hours. Norepinephrine was administered in 83% of cases with a dose of 0.25 (0.15–0.42) µg/kg/min. The positive end-expiratory pressure was 14 (11–16) cmH2O. The driving pressure was 12 (10–17) cmH2O, and the respiratory system compliance was 32 (22–40) mL/cmH2O. Preload responsiveness was detected in 42 cases. An absolute change in PPV ≥ 3.5% during a TVC assessed preload responsiveness with an area under the receiver operating characteristics (AUROC) curve of 0.94 ± 0.03 (sensitivity: 98%, specificity: 86%) better than that of baseline PPV (0.85 ± 0.05; p = 0.047). In the 56 cases where baseline PPV was inconclusive (≥ 4% and < 11%), ΔPPV TVC6–8 ≥ 3.5% still enabled to reliably assess preload responsiveness (AUROC: 0.91 ± 0.05, sensitivity: 97%, specificity: 81%; p < 0.01 vs. baseline PPV).ConclusionIn patients with ARDS under low tidal volume ventilation during prone position, the changes in PPV during a TVC can reliably assess preload responsiveness without the need for cardiac output measurements.Trial registration: ClinicalTrials.gov (NCT04457739). Registered 30 June 2020 —Retrospectively registered, https://clinicaltrials.gov/ct2/show/record/NCT04457739

The use of pulse pressure variation for predicting impairment of microcirculatory blood flow

Dynamic parameters of preload have been widely recommended to guide fluid therapy based on the principle of fluid responsiveness and with regard to cardiac output. An equally important aspect is however to also avoid volume-overload. This accounts particularly when capillary leakage is present and volume-overload will promote impairment of microcirculatory blood flow. The aim of this study was to evaluate, whether an impairment of intestinal microcirculation caused by volume-load potentially can be predicted using pulse pressure variation in an experimental model of ischemia/reperfusion injury. The study was designed as a prospective explorative large animal pilot study. The study was performed in 8 anesthetized domestic pigs (German landrace). Ischemia/reperfusion was induced during aortic surgery. 6 h after ischemia/reperfusion-injury measurements were performed during 4 consecutive volume-loading-steps, each consisting of 6 ml kg−1 bodyweight−1. Mean microcirculatory blood flow (mean Flux) of the ileum was measured using direct laser-speckle-contrast-imaging. Receiver operating characteristic analysis was performed to determine the ability of pulse pressure variation to predict a decrease in microcirculation. A reduction of ≥ 10% mean Flux was considered a relevant decrease. After ischemia–reperfusion, volume-loading-steps led to a significant increase of cardiac output as well as mean arterial pressure, while pulse pressure variation and mean Flux were significantly reduced (Pairwise comparison ischemia/reperfusion-injury vs. volume loading step no. 4): cardiac output (l min−1) 1.68 (1.02–2.35) versus 2.84 (2.15–3.53), p = 0.002, mean arterial pressure (mmHg) 29.89 (21.65–38.12) versus 52.34 (43.55–61.14), p < 0.001, pulse pressure variation (%) 24.84 (17.45–32.22) versus 9.59 (1.68–17.49), p = 0.004, mean Flux (p.u.) 414.95 (295.18–534.72) versus 327.21 (206.95–447.48), p = 0.006. Receiver operating characteristic analysis revealed an area under the curve of 0.88 (CI 95% 0.73–1.00; p value < 0.001) for pulse pressure variation for predicting a decrease of microcirculatory blood flow. The results of our study show that pulse pressure variation does have the potential to predict decreases of intestinal microcirculatory blood flow due to volume-load after ischemia/reperfusion-injury. This should encourage further translational research and might help to prevent microcirculatory impairment due to excessive fluid resuscitation and to guide fluid therapy in the future.

A comparative study of pulse pressure variation, stroke volume variation and central venous pressure in patients undergoing kidney transplantation.

Optimal intraoperative fluid management guided by central venous pressure (CVP), a traditional intravascular volume status indicator, has improved transplanted graft function during kidney transplantation (KT). Pulse pressure variation (PPV) and stroke volume variation (SVV) - dynamic preload indexes - are robust predictors of fluid responsiveness. This study aimed to compare the accuracy of PPV and CVP against SVV in predicting fluid responsiveness in terms of cost-effectiveness after a standardised empiric volume challenge in KT patients. 36 patients undergoing living-donor KT were analysed. PPV, SVV, CVP and cardiac index (CI) were measured before and after fluid loading with a hydroxyethyl starch solution (7 mL/kg of ideal body weight). Patients were classified as responders (n = 12) or non-responders (n = 24) to fluid loading when CI increases were ≥10% or <10%, respectively. The ability of PPV, SVV and CVP to predict fluid responsiveness was assessed using receiver operating characteristic (ROC) curves. SVV and CVP measured before fluid loading were correlated with changes in CI caused by fluid expansion (ρ = 0.33, P = 0.049 and ρ = -0.37, P = 0.026) in contrast to PPV (ρ = 0.14, P = 0.429). The ROC analysis showed that SVV and CVP predicted response to volume loading (area under the ROC curve = 0.781 and 0.727, respectively; P < 0.05). Under the conditions of our study, SVV and CVP exhibited similar performance in predicting fluid responsiveness and could inform fluid management during KT as compared with PPV.

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

BackgroundThis 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 methodsA 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.ResultsIn 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.ConclusionBoth PPV and PVI were able to predict fluid responsiveness; their predictive abilities were maintained in the prone position.

Pulse Pressure Variation Adjusted by Respiratory Changes in Pleural Pressure, Rather Than by Tidal Volume, Reliably Predicts Fluid Responsiveness in Patients With Acute Respiratory Distress Syndrome.

1) To evaluate the ability of pulse pressure variation adjusted by respiratory changes in pleural pressure to predict fluid responsiveness compared with pulse pressure variation alone. 2) To identify factors explaining the poor performance of pulse pressure variation in acute respiratory distress syndrome. Prospective study. Forty-bed university hospital general ICU. Ninety-six mechanically ventilated acute respiratory distress syndrome patients requiring fluid challenge. Fluid challenge, 500 mL saline over 20 minutes. Before fluid challenge, esophageal pressure was measured at the end-inspiratory and end-expiratory occlusions. Change in pleural pressure was calculated as the difference between esophageal pressure measured at end-inspiratory and end-expiratory occlusions. Hemodynamic measurements were obtained before and after the fluid challenge. Patients were ventilated with tidal volume 7.0 ± 0.8 mL/kg predicted body weight. The fluids increased cardiac output by greater than 15% in 52 patients (responders). Adjusting pulse pressure variation for changes in pleural pressure (area under the receiver operating characteristic curve, 0.94 [0.88-0.98]) and the ratio of chest wall elastance to total respiratory system elastance (area under the receiver operating characteristic curve, 0.93 [0.88-0.98]) predicted fluid responsiveness better than pulse pressure variation (area under the receiver operating characteristic curve, 0.78 [0.69-0.86]; all p < 0.01). The gray zone approach identified a range of pulse pressure variation/changes in pleural pressure values (1.94-2.1) in 3.1% of patients for whom fluid responsiveness could not be predicted reliably. On logistic regression analysis, two independent factors affected the correct classification of fluid responsiveness at a 12% pulse pressure variation cutoff: tidal volume (adjusted odds ratio 1.57/50 mL; 95% CI, 1.05-2.34; p = 0.027) and chest wall elastance/respiratory system elastance (adjusted odds ratio, 2.035/0.1 unit; 95% CI, 1.36-3.06; p = 0.001). In patients with chest wall elastance/respiratory system elastance above the median (0.28), pulse pressure variation area under the receiver operating characteristic curve was 0.94 (95% CI, 0.84-0.99) compared with 0.76 (95% CI, 0.61-0.87) otherwise (p = 0.02). In acute respiratory distress syndrome patients, pulse pressure variation adjusted by changes in pleural pressure is a reliable fluid responsiveness predictor despite the low tidal volume (< 8 mL/kg). The poor predictive ability of pulse pressure variation in acute respiratory distress syndrome patients is more related to low chest wall elastance/respiratory system elastance ratios than to a low tidal volume.

Stroke volume variation compared with pulse pressure variation and cardiac index changes for prediction of fluid responsiveness in mechanically ventilated patients

IntroductionAdequate volume resuscitation is very important for a favorable outcome of critically ill patients. Both over and under filling of intravascular volume could be deleterious. Static indices including central venous pressure, pulmonary capillary wedge pressure, left ventricular end-diastolic area, mean arterial pressure (MAP) and tachycardia are commonly used and are known to be of little value in discriminating responders from non-responders. On the other hand dynamic indices such as pulse pressure variation (PPV), inferior vena cava diameter, superior vena cava diameter, aortic blood flow, which are based on variation on the left ventricular stoke volume, have been shown to be more accurate predictors of fluid responsiveness in mechanically ventilated patients. In this study we are evaluating the ability of stroke volume variation (SVV) obtained by Vigileo–FloTrac device to predict fluid responsiveness in patients with acute circulatory failure under complete passive, volume controlled mechanical ventilation and correlating it to manually calculated PPV. Materials and methodsTwenty five patients aged above 18years, with acute circulatory failure and at least one sign of tissue hypoperfusion requiring fluid resuscitation and mechanical ventilation were included. Excluded are patients with cardiogenic shock, acute pulmonary edema, LVEF <50%, atrial fibrillation, frequent ectopics, significant aortic or mitral valve abnormalities or renal failure. Candidates were subjected to thorough clinical evaluation, lab investigation and ECG. Following sedation, muscle relaxation and maintenance of mean arterial pressure >65mmHg by norepinephrine, 500ml of Hes-steril were administered over 10min. Static and dynamic hemodynamic parameters were taken in supine position before and after fluid challenge. Patients who had an increase of cardiac index measured by trans-thoracic echocardiography ⩾15% of baseline measurement were considered responders. ResultsFourteen patients were fluid responders. Before fluid challenge SVV and PPV were significantly higher in responders than non-responders (p=0.0001 for each). SVV⩾8.15% predicted responders with a sensitivity of 100% and specificity 81.1% (AUC 0.906). PPV⩾10.2 also predicted responders with a sensitivity of 92.9% and specificity of 90.9% (AUC 0.974). The higher the SVV before fluid challenge the higher the percentage of increase of CI following fluid challenge (r=0.733, p=0.00). PPV showed the same correlation pattern with percentage increase of CI (r=0.798, p=0.00). ConclusionsBaseline stroke volume variation ⩾8.15% predicted fluid responsiveness in mechanically ventilated patients with acute circulatory failure. The study also confirmed the ability of pulse pressure variation to predict fluid responsiveness.

Pulse pressure variation is not a valid predictor of fluid responsiveness in patients with elevated left ventricular filling pressure

PurposeThe purpose of this study was to test the hypothesis that the predictive ability of pulse pressure variation (PPV) for fluid responsiveness would be altered in patients with elevated left ventricular (LV) filling pressure. Materials and methodsAccording to the preoperative echocardiographic assessment of the ratio of early transmitral flow velocity to early diastolic velocity of the mitral annulus (E/E′), patients undergoing surgical coronary revascularization were classified into normal (n = 34, E/E′ <8) and high (n = 34, E/E′ >15) LV filling pressure group. After anesthetic induction, PPV and hemodynamic data were measured before and after 6 mL/kg of colloid administration. Fluid responsiveness was defined as 12% or more increase in stroke volume index assessed by pulmonary artery catheter and tested by the area under the receiver operating characteristic curve (AUROC). ResultsThe AUROCs of PPV in the normal and high filling pressure group were 0.829 (95% confidence interval [CI], 0.661-0.963; P < .001) and 0.583 (95% CI, 0.402-0.749; P = .110), respectively. The AUROCs of cardiac filling pressures and right ventricular end-diastolic volume index did not show statistical significance in both groups. ConclusionsNone of the assessed preload indices including PPV were able to predict fluid responsiveness in patients with elevated LV filling pressure.

Validation of pulse pressure variation and corrected flow time as predictors of fluid responsiveness in patients in the prone position

The aim of this prospective trial was to investigate the ability of pulse pressure variation (PPV) and corrected flow time (FTc) to predict fluid responsiveness in the prone position. Forty-four patients undergoing lumbar spine surgery in the prone position on a Wilson frame were prospectively studied. PPV and FTc were measured before and after a colloid bolus (6 ml kg(-1)) both in the supine and in the prone positions. Fluid responsiveness was defined as an increase in the stroke volume index of ≥ 10% as measured by oesophageal Doppler. In the supine position, 26 patients were responders and the areas under the curve (AUC) of the receiver-operator characteristic (ROC) curves of PPV and FTc were 0.935 [95% confidence interval (CI): 0.870-0.999, P<0.001] and 0.822 (95% CI: 0.682-0.961, P<0.001), respectively. The optimal cut-off PPV and FTc values were 15% (sensitivity 73%, specificity 94%) and 358 ms (sensitivity 88%, specificity 78%), respectively. In the prone position, 34 patients were responders and the AUCs of PPV and FTc were 0.969 (95% CI: 0.912-1.000, P<0.001) and 0.846 (95% CI: 0.706-0.985, P=0.001), respectively. The optimal cut-off PPV and FTc values were 14% (sensitivity 97%, specificity 90%) and 331 ms (sensitivity 77%, specificity 90%), respectively. While the predictability of PPV was significantly higher than that of FTc in the prone position, both variables showed high predictability and remained as useful indices for guiding fluid therapy in prone patients with minimal alterations in their optimal cut-off values to predict fluid responsiveness. Clinical trial registration URL: http://www.clinicaltrials.gov/ct2/show/NCT01646359?term=NCT01646359&rank=1 and unique identification number NCT01646359.

Pulse pressure variation and stroke volume variation to predict fluid responsiveness in patients undergoing carotid endarterectomy

BackgroundDuring carotid endarterectomy (CEA), hemodynamic stability and adequate fluid management are crucial to prevent perioperative cerebral stroke, myocardial infarction and hyperperfusion syndrome. Both pulse pressure variation (PPV) and stroke volume variation (SVV), dynamic preload indices derived from the arterial waveform, are increasingly advocated as predictors of fluid responsiveness in mechanically ventilated patients. The aim of this study was to evaluate the accuracy of PPV and SVV for predicting fluid responsiveness in patients undergoing CEA.MethodsTwenty seven patients undergoing CEA were enrolled in this study. PPV, SVV and cardiac output (CO) were measured before and after fluid loading of 500 ml of hydroxyethyl starch solution. Fluid responsiveness was defined as an increase in CO ≥ 15%. The ability of PPV and SVV to predict fluid responsiveness was assessed using receiver operating characteristic (ROC) analysis.ResultsBoth PPV and SVV measured before fluid loading are associated with changes in CO caused by fluid expansion. The ROC analysis showed that PPV and SVV predicted response to volume loading (area under the ROC curve = 0.854 and 0.841, respectively, P < 0.05). A PPV ≥ 9.5% identified responders (Rs) with a sensitivity of 71.4% and a specificity of 90.9%, and a SVV ≥ 7.5% identified Rs with a sensitivity of 92.9% and a specificity of 63.6%.ConclusionsBoth PPV and SVV values before volume loading are associated with increased CO in response to volume expansion. Therefore, PPV and SVV are useful predictors of fluid responsiveness in patients undergoing CEA.

Passive leg-raising and end-expiratory occlusion tests perform better than pulse pressure variation in patients with low respiratory system compliance*

We tested whether the poor ability of pulse pressure variation to predict fluid responsiveness in cases of acute respiratory distress syndrome was related to low lung compliance. We also tested whether the changes in cardiac index induced by passive leg-raising and by an end-expiratory occlusion test were better than pulse pressure variation at predicting fluid responsiveness in acute respiratory distress syndrome patients. Prospective study. Medical intensive care unit. We included 54 patients with circulatory shock (63 ± 13 yrs; Simplified Acute Physiology Score II, 63 ± 24). Twenty-seven patients had acute respiratory distress syndrome (compliance of the respiratory system, 22 ± 3 mL/cm H2O). In nonacute respiratory distress syndrome patients, the compliance of the respiratory system was 45 ± 9 mL/cm H2O. We measured the response of cardiac index (transpulmonary thermodilution) to fluid administration (500 mL saline). Before fluid administration, we recorded pulse pressure variation and the changes in pulse contour analysis-derived cardiac index induced by passive leg-raising and end-expiratory occlusion. Fluid increased cardiac index ≥ 15% (44% ± 39%) in 30 "responders." Pulse pressure variation was significantly correlated with compliance of the respiratory system (r = .58), but not with tidal volume. The higher the compliance of the respiratory system, the better the prediction of fluid responsiveness by pulse pressure variation. A compliance of the respiratory system of 30 mL/cm H2O was the best cut-off for discriminating patients regarding the ability of pulse pressure variation to predict fluid responsiveness. If compliance of the respiratory system was >30 mL/cm H2O, then the area under the receiver-operating characteristics curve for predicting fluid responsiveness was not different for pulse pressure variation and the passive leg-raising and end-expiratory occlusion tests (0.98 ± 0.03, 0.91 ± 0.06, and 0.97 ± 0.03, respectively). By contrast, if compliance of the respiratory system was ≤ 30 mL/cm H2O, then the area under the receiver-operating characteristics curve was significantly lower for pulse pressure variation than for the passive leg-raising and end-expiratory occlusion tests (0.69 ± 0.10, 0.94 ± 0.05, and 0.93 ± 0.05, respectively). The ability of pulse pressure variation to predict fluid responsiveness was inversely related to compliance of the respiratory system. If compliance of the respiratory system was ≤ 30 mL/cm H2O, then pulse pressure variation became less accurate for predicting fluid responsiveness. However, the passive leg-raising and end-expiratory occlusion tests remained valuable in such cases.

Pulse Pressure Variation Predicts Fluid Responsiveness in Elderly Patients After Coronary Artery Bypass Graft Surgery

To assess the ability of pulse pressure variation to predict fluid responsiveness in mechanically ventilated elderly patients after coronary artery bypass graft surgery. A prospective, interventional study. An academic, tertiary referral hospital. Sixty patients >70 years old and mechanically ventilated after coronary artery bypass graft surgery. Intravascular volume expansion using 6% hydroxyethyl starch solution, 7 mL/kg over 20 minutes. Heart rate, arterial blood pressure, pulse pressure variation, central venous pressure, pulmonary artery occlusion pressure, and stroke volume index were measured immediately before and after volume expansion. Fluid responsiveness was defined as an increase in stroke volume index ≥ 15% after volume expansion. Forty-one patients were fluid responders and 19 patients were nonresponders. In contrast to central venous pressure or pulmonary artery occlusion pressure, pulse pressure variation was higher in the responders than in the nonresponders (22 ± 6% v 9.3 ± 3%, p = 0.001) and correlated with the percent changes in the stroke volume index after volume expansion (r = 0.47, p = 0.001). The area under the receiver operating characteristic curve for pulse pressure variation was 0.85 (95% confidence interval 0.75-0.94). The threshold value of 11.5% allowed the discrimination between responders and nonresponders with a sensitivity of 80% and a specificity of 74%. Pulse pressure variation is a reliable predictor of fluid responsiveness in mechanically ventilated elderly patients after coronary artery bypass graft surgery.

Pulse pressure variation as a predictor of fluid responsiveness during one-lung ventilation for lung surgery using thoracotomy: randomised controlled study

Pulse pressure variation (PPV) is increasingly advocated as a predictor of fluid responsiveness in patients receiving mechanical ventilation. However, the ability of PPV has never been studied during one-lung ventilation (OLV). Therefore, we evaluated the value of PPV to predict fluid responsiveness in patients receiving conventional and protective OLV using receiver operating characteristic (ROC) analysis, respectively. Forty-nine patients undergoing lung surgery requiring OLV were enrolled in this study. Patients were randomised either to group P [patients receiving protective OLV with tidal volume 6 ml kg, inspired oxygen fraction (FIO2) of 0.5 and positive end-expiratory pressure (PEEP) of 5 cmH2O) or group C (patients receiving conventional OLV with tidal volume of 10 ml kg, FIO2 of 1.0 and no PEEP). Following OLV, PPV and cardiac output were measured before and 12 min after fluid loading (7 ml kg hydroxyethyl starch 6%). Patients whose cardiac indices increased by at least 15% to fluid loading were defined as the responders. The areas under ROC curve for PPV were 0.857 (P = 0.006) in group P and 0.524 (P = 0.839) in group C, respectively. The optimal threshold value given by ROC analysis for PPV was 5.8% in group P. PPV could predict fluid responsiveness only during protective OLV, but not conventional OLV. PPV would be helpful for fluid management in patients receiving protective OLV for lung surgery using thoracotomy.

The value of pulse pressure and stroke volume variation as predictors of fluid responsiveness during open chest surgery

We investigated the ability of pulse pressure variation and stroke volume variation to predict fluid responsiveness during mechanical ventilation in patients undergoing open chest surgery by comparing their respective correlations with cardiac output changes induced by leg elevation. Serial leg elevation manoeuvres were performed before and after sternotomy in 15 patients scheduled for elective off-pump coronary bypass surgery. Under closed chest conditions, both pulse pressure variation and stroke volume variation correlated well with the induced cardiac output changes (r = 0.856, p = 0.002 and r = 0.897, p = 0.0012, respectively). These correlations were lost for both parameters following sternotomy. Our data show that pulse pressure variation and stroke volume variation are valid predictors of fluid responsiveness under closed chest conditions but that this property no longer holds when the chest is open.