Pulse Contour Analysis Research Articles

Local gastric RAAS inhibition improves gastric microvascular perfusion in dogs.

During circulatory shock, gastrointestinal microcirculation is impaired, especially via activation of the renin-angiotensin-aldosterone system. Therefore, inhibition of the renin-angiotensin-aldosterone system might be beneficial in maintaining splanchnic microcirculation. The aim of this study was to analyze whether locally applied losartan influences gastric mucosal perfusion (µflow, µvelo) and oxygenation (µHbO2) without systemic hemodynamic changes. In repetitive experiments six anesthetized dogs received 30 mg losartan topically on the oral and gastric mucosa during normovolemia and hemorrhage (-20% blood volume). Microcirculatory variables were measured with reflectance spectrometry, laser Doppler flowmetry and incident dark field imaging. Transpulmonary thermodilution and pulse contour analysis were used to measure systemic hemodynamic variables. Gastric barrier function was assessed via differential absorption of inert sugars. During normovolemia, losartan increased gastric µflow from 99 ± 6 aU to 147 ± 17 aU and µvelo from 17 ± 1 aU to 19 ± 1 aU. During hemorrhage, losartan did not improve µflow. µvelo decreased from 17 ± 1 aU to 14 ± 1 aU in the control group. Application of losartan did not significantly alter µvelo (16 ± 1 aU) compared to the control group and to baseline levels (17 ± 1 aU). No effects of topical losartan on macrohemodynamic variables or microcirculatory oxygenation were detected. Gastric microcirculatory perfusion is at least partly regulated by local angiotensin receptors. Topical application of losartan improves local perfusion via vasodilation without significant effects on systemic hemodynamics. During mild hemorrhage losartan had minor effects on regional perfusion, probably because of a pronounced upstream vasoconstriction.

Transpulmonary thermodilution techniques in the haemodynamically unstable patient.

Transpulmonary thermodilution (TPTD) devices invasively measure not only cardiac output but also several other haemodynamic variables estimating cardiac preload, cardiac preload, systolic function, the lung oedema and systolic function, the lung oedema and the pulmonary permeability. In light of the recent literature, we describe how different indices are measured, emphasize their clinical interest and list potential limits and side-effects of the technique. Estimation of cardiac output measurement with TPTD is now well established, at least when compared with the pulmonary artery catheter. The advantage of calibrating the pulse contour analysis, as it is allowed by TPTD indices, is clearly established over uncalibrated devices. The greatest advantage of TPTD is to measure extravascular lung water and pulmonary permeability, which may be useful to diagnose acute respiratory distress syndrome and manage fluid therapy in various critical diseases. It also allows a rapid detection of left ventricular systolic failure. The information it provides must be considered complementary to that provided by echocardiography. TPTD provides several indices that may help in making decisions during the therapeutic management of haemodynamically unstable patients. It should be used for the most critically ill patients, whose management requires a reliable, precise and holistic view of the cardiopulmonary condition.

Ability of a New Smartphone Pulse Pressure Variation and Cardiac Output Application to Predict Fluid Responsiveness in Patients Undergoing Cardiac Surgery.

Pulse pressure variation (PPV) can be used to predict fluid responsiveness in anesthetized patients receiving controlled mechanical ventilation but usually requires dedicated advanced monitoring. Capstesia (Galenic App, Vitoria-Gasteiz, Spain) is a novel smartphone application that calculates PPV and cardiac output (CO) from a picture of the invasive arterial pressure waveform obtained from any monitor screen. The primary objective was to compare the ability of PPV obtained using the Capstesia (PPVCAP) and PPV obtained using a pulse contour analysis monitor (PPVPC) to predict fluid responsiveness. A secondary objective was to assess the agreement and the trending of CO values obtained with the Capstesia (COCAP) against those obtained with the transpulmonary bolus thermodilution method (COTD). We studied 57 mechanically ventilated patients (tidal volume 8 mL/kg, positive end-expiratory pressure 5 mm Hg, respiratory rate adjusted to keep end tidal carbon dioxide [32-36] mm Hg) undergoing elective coronary artery bypass grafting. COTD, COCAP, PPVCAP, and PPVPC were measured before and after infusion of 5 mL/kg of a colloid solution. Fluid responsiveness was defined as an increase in COTD of >10% from baseline. The ability of PPVCAP and PPVPC to predict fluid responsiveness was analyzed using the area under the receiver-operating characteristic curve (AUROC), the agreement between COCAP and COTD using a Bland-Altman analysis and the trending ability of COCAP compared to COTD after volume expansion using a 4-quadrant plot analysis. Twenty-eight patients were studied before surgical incision and 29 after sternal closure. There was no significant difference in the ability of PPVCAP and PPVPC to predict fluid responsiveness (AUROC 0.74 [95% CI, 0.60-0.84] vs 0.68 [0.54-0.80]; P = .30). A PPVCAP >8.6% predicted fluid responsiveness with a sensitivity of 73% (95% CI, 0.54-0.92) and a specificity of 74% (95% CI, 0.55-0.90), whereas a PPVPC >9.5% predicted fluid responsiveness with a sensitivity of 62% (95% CI, 0.42-0.88) and a specificity of 74% (95% CI, 0.48-0.90). When measured before surgery, PPV predicted fluid responsiveness (AUROC PPVCAP = 0.818 [P = .0001]; PPVPC = 0.794 [P = .0007]) but not when measured after surgery (AUROC PPVCAP = 0.645 [P = .19]; PPVPC = 0.552 [P = .63]). A Bland-Altman analysis of COCAP and COTD showed a mean bias of 0.3 L/min (limits of agreement: -2.8 to 3.3 L/min) and a percentage error of 60%. The concordance rate, corresponding to the proportion of CO values that changed in the same direction with the 2 methods, was poor (71%, 95% CI, 66-77). In patients undergoing cardiac surgery, PPVCAP and PPVPC both weakly predict fluid responsiveness. However, COCAP is not a good substitute for COTD and cannot be used to assess fluid responsiveness.

Influence of changes in ventricular systolic function and loading conditions on pulse contour analysis-derived femoral dP/dtmax

BackgroundFemoral dP/dtmax (maximum rate of the arterial pressure increase during systole) measured by pulse contour analysis has been proposed as a surrogate of left ventricular (LV) dP/dtmax and as an estimator of LV systolic function. However, femoral dP/dtmax may be influenced by LV loading conditions. In this study, we evaluated the impact of variations of LV systolic function, preload and afterload on femoral dP/dtmax in critically ill patients with cardiovascular failure to ascertain its reliability as a marker of LV systolic function.ResultsWe performed a prospective observational study to evaluate changes in femoral dP/dtmax, thermodilution-derived variables (PiCCO2—Pulsion Medical Systems, Feldkirchen, Germany) and LV ejection fraction (LVEF) measured by transthoracic echocardiography during variations in dobutamine and norepinephrine doses and during volume expansion (VE) and passive leg raising (PLR). Correlations with arterial pulse and systolic pressure, effective arterial elastance, total arterial compliance and LVEF were also evaluated. In absolute values, femoral dP/dtmax deviated from baseline by 21% (201 ± 297 mmHg/s; p = 0.013) following variations in dobutamine dose (n = 17) and by 15% (177 ± 135 mmHg/s; p < 0.001) following norepinephrine dose changes (n = 29). Femoral dP/dtmax remained unchanged after VE and PLR (n = 24). Changes in femoral dP/dtmax were strongly correlated with changes in pulse pressure and systolic arterial pressure during dobutamine dose changes (R = 0.942 and 0.897, respectively), norepinephrine changes (R = 0.977 and 0.941, respectively) and VE or PLR (R = 0.924 and 0.897, respectively) (p < 0.05 in all cases). Changes in femoral dP/dtmax were correlated with changes in LVEF (R = 0.527) during dobutamine dose variations but also with effective arterial elastance and total arterial compliance in the norepinephrine group (R = 0.638 and R = − 0.689) (p < 0.05 in all cases).ConclusionsPulse contour analysis-derived femoral dP/dtmax was not only influenced by LV systolic function but also and prominently by LV afterload and arterial waveform characteristics in patients with acute cardiovascular failure. These results suggest that femoral dP/dtmax calculated by pulse contour analysis is an unreliable estimate of LV systolic function during changes in LV afterload and arterial load by norepinephrine and directly linked to arterial waveform determinants.

The age‐related reduction in cerebral blood flow affects vertebral artery more than internal carotid artery blood flow

Ageing reduces cerebral blood flow (CBF), while mean arterial pressure (MAP) becomes elevated. According to 'the selfish brain' hypothesis of hypertension, a reduction in vertebral artery blood flow (VA) leads to increased sympathetic activity and thus increases MAP. In twenty-two young (24±3years; mean±SD) and eleven elderly (70±5years) normotensive men, duplex ultrasound evaluated whether the age-related reduction in CBF affects VA more than internal carotid artery (ICA) blood flow. Pulse-contour analysis evaluated MAP while near-infrared spectroscopy determined frontal lobe oxygenation and transcranial Doppler middle cerebral artery mean blood velocity (MCA Vmean ). During supine rest, MAP (90±13 versus 78±9mmHg; P<0·001) was elevated in the older subjects while their frontal lobe oxygenation (68±7% versus 77±7%; P<0·001), MCA Vmean (49±9 versus 60±12cm s-1 ; P=0·016) and CBF (754±112 versus 900±144mlmin-1 ; P=0·004) were low reflected in VA (138±48 versus 219±50mlmin-1 ; P<0·001) rather than in ICA flow (616±96 versus 680±120mlmin-1 ; P=0·099). In conclusion, blood supply to the brain and its oxygenation are affected by ageing and the age-related decline in VA flow appears to be four times as large as that in ICA and could be important for the age-related increase in MAP.

Accuracy of the ClearSight™ system in patients undergoing abdominal aortic aneurysm surgery.

The ClearSight™ device monitors continuous pressure and cardiac output via pulse contour analysis. ClearSight™, however, may not be reliable in patients with reduced peripheral perfusion caused by high peripheral resistance. This study aimed to elucidate the accuracy and trending ability of ClearSight™ in patients undergoing abdominal aortic aneurysm (AAA) surgery by comparing the ClearSightTM-derived cardiac index (CICS) with that measured using three-dimensional echocardiography (CI3D). The study included 20 patients who underwent elective AAA surgery. CICS and CI3D were measured simultaneously at eight time points during the surgery. Trending ability was investigated after aortic clamping and unclamping. We used CI3D as the reference method. Bland-Altman analysis showed a wide limit of agreement between CICS and CI3D (percentage error 41.3%). Subgroup analysis showed a lower percentage error (33.2%) in patients with CI ≥ 2.5L/min/m2. The cubic splines related to the CI3D and CI discrepancy were negatively sloped, indicating that CI3D had significant influence on the CI discrepancy (p < 0.001). Four-quadrant plot analysis showed that the tracking ability of ClearSight™ after aortic clamping and declamping were clinically unacceptable (81.3% and 78.6%, respectively). Also, the polar plot analysis showed that the concordance rate of ClearSight™ after aortic clamping and declamping were clinically unacceptable (58.3% and 66.7%, respectively). ClearSight™ was not sufficiently accurate in patients undergoing AAA surgery. The tracking ability of ClearSight™ after aortic clamping was below the acceptable limit.

Comparison of beta2-adrenergic and hyperemia-induced arterial vasodilation assessed by digital pulse contour analysis

Introduction. The Reflection Index (RIDVP) derived from digital volume pulse (DVP) analysis has proved to be useful in the assessment of endothelium‑dependent vasodilation induced by albuterol. Little is known of the effect of shear‑stress‑induced vasorelaxation on RIDVP.Material and Methods. Thirty three healthy volunteers (22 females, 11 males, mean age 57 yrs) were recruited. Assessment of endothelium‑dependent vasorelaxation was performed by the analysis of digital volume pulse after albuterol challenge or locally‑induced hyperemia. Results. he hyperemia‑induced vasodilation led to a significant decrease of RIDVP in comparison with the values obtained at rest (∆RIHyper 69 ± 2 % vs 64 ± 2, p &lt; 0.0001). Similarly albuterol administration resulted in a significant drop in RIDVP (∆RIAlb 71 ± 2 % vs 67 ± 2 %, p &lt; 0.0001). There was no significant difference between ∆RIHyper and ∆RIAlb (5.2 ± 0.8 % vs 4.6 ± 1.0 %, p = 0.61). We observed a significant correlation between the small vessel reaction in response to albuterol or hyperemia (r = 0.52, p = 0.01).Conclusions. Our study demonstrated that hyperemia‑induced changes in the Reflexion Index derived from the digital volume pulse are similar to those observed after albuterol‑challenge and both are correlated.

Abstract P1-12-06: Endothelial dysfunction in breast cancer survivors on aromatase inhibitors (AIs) over time

Abstract Endothelial dysfunction in breast cancer survivors on aromatase inhibitors (AIs) over time Background: AIs reduce breast cancer-related mortality however they may increase cardiovascular (CV) risk. Our previously published cross-sectional study suggested women on AIs were more likely to have endothelial dysfunction when measured by EndoPAT ratio as compared to healthy postmenopausal women. Reductions in EndoPAT ratio (&amp;lt;1.67) and small artery elasticity (SAE) and increases in highly sensitive C-reactive protein (CRP) are associated with worsening endothelial dysfunction and increased cardiovascular events. We present data from a longitudinal pilot study looking at endothelial dysfunction over time in women on AIs. Methods: Fourteen women with locally advanced breast cancer prescribed an AI underwent vascular testing at baseline (pre-AI) and at 6 months. Subjects with tobacco use, hypertension or hyperlipidemia were excluded. Consented subjects underwent biomarker analysis and radial artery pulse wave analysis using the HDI/Pulse Wave CR-2000 CV Profiling System and pulse contour analysis using the Endo-PAT2000 system. Biomarkers were obtained using a fasting blood draw to evaluate the following lipids and inflammatory markers: serum ultrasensitive estradiol, serum glucose, total cholesterol (TC), low-density lipoprotein cholesterol (LDL), high-density lipoprotein cholesterol (HDL), and triglycerides (TG), CRP, plasminogen-activator 1 (PA1), and tissue-type plasminogen activator (tPA). Changes between baseline and follow-up using Wilcoxon signed-rank tests were analyzed. Results: Mean baseline age was 59 years and median body mass index was 26.5 kg/m2. Median systolic blood pressure and total cholesterol were 120/70 mm/Hg and 228 mg/dL, respectively. Baseline ultrasensitive estradiol levels were 7 pg/mL and hsCRP was 2.45 mg/dL. Prior to AI therapy, endoPAT ratio was 2.18 (1.19, 2.43). After six months, EndoPAT ratio declined to a median 1.12 (0.85, 1.86) (p=0.045). There were no statistically significant changes in serum glucose, TC, LDL, HDL, hsCRP, PA1 and tPA. HsCRP remained elevatedat median 2.98 mg/L. At six months, estradiol levels decreased to a median of 2 pg/mL (p=0.052), however, there appeared to be no linear association between changes in EndoPAT and estradiol (p=0.91). Conclusion: Breast cancer survivors on AIs have endothelial dysfunction, a predictor of adverse CV disease. These changes develop while on AIs. Underlying pathophysiology requires further evaluation. Cardiovascular markersMeasuresBaselineFollow-Up at 6 MonthsChangeP-valueBMI (kg/m2)26.5 (24.4, 31.6)27.1 (23.9, 32.9)0.5 (0.0, 1.3)0.056SBP (mmHg)120 (115, 124)123 (114, 127)-0.8 (-7.4, 3.6)0.91DBP (mmHg)70 (61, 73)69 (62, 71)0.0 (-3.0, 2.6)0.88Total Cholesterol (mg/dL)228 (202, 244)213 (210, 229)-1 (-18, 27)0.70HDL (mg/dL)64 (58, 69)73 (61, 77)2 (-3, 14)0.44LDL (mg/dL)143 (121, 159)129 (120, 142)6 (-11, 14)0.65Estradiol (pg/mL)7 (4, 15)2 (2, 3)-8 (-12, -3)0.05hsCRP (mg/dL)2.45 (1.14, 6.07)2.98 (0.90, 4.81)-8 (-12, -3)0.85EndoPAT Ratio2.18 (1.19, 2.43)1.12 (0.85, 1.86)-0.16 (-1.45, -0.02)0.0451.Summaries shown are median (1st quartile, 3rd quartile). Citation Format: Blaes AH, Petersen A, Beckwith H, Potter D, Florea N, Yee D, Vogel R, Duprez D. Endothelial dysfunction in breast cancer survivors on aromatase inhibitors (AIs) over time [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-12-06.

Esophageal Doppler Can Predict Fluid Responsiveness Through End-Expiratory and End-Inspiratory Occlusion Tests.

To assess whether, in patients under mechanical ventilation, fluid responsiveness is predicted by the effects of short respiratory holds on cardiac index estimated by esophageal Doppler. Prospective, monocentric study. Medical ICU. Twenty-eight adult patients with acute circulatory failure and a decision of the clinicians in charge to administer fluids. Before and after infusing 500 mL of saline, we measured cardiac index estimated by esophageal Doppler before and during the last 5 seconds of successive 15-second end-inspiratory occlusion and end-expiratory occlusion, separated by 1 minute. Patients in whom volume expansion increased cardiac index measured by transpulmonary thermodilution greater than or equal to 15% were defined as "fluid responders." Cardiac index measured by the Pulse Contour Cardiac Output device (from pulse contour analysis or transpulmonary thermodilution) was used as the reference. End-expiratory occlusion increased cardiac index estimated by esophageal Doppler more in responders than in nonresponders (8% ± 2% vs 3% ± 1%, respectively; p < 0.0001) and end-inspiratory occlusion decreased cardiac index estimated by esophageal Doppler more in responders than in nonresponders (-8% ± 5% vs -4% ± 2%, respectively; p = 0.0002). Fluid responsiveness was predicted by the end-expiratory occlusion induced percent change in cardiac index estimated by esophageal Doppler with an area under the receiver operating characteristic curve of 1.00 (95% CI, 0.88-1.00) and a threshold value of 4% increase in cardiac index estimated by esophageal Doppler. It was predicted by the sum of absolute values of percent changes in cardiac index estimated by esophageal Doppler during both occlusions with a similar area under the receiver operating characteristic curve (0.99 [0.86-1.00]) and with a threshold of 9% change in cardiac index estimated by esophageal Doppler, which is compatible with the esophageal Doppler precision. If the absolute sum of the percent change in cardiac index estimated by esophageal Doppler induced by two successive end-inspiratory occlusion and end-expiratory occlusion maneuvers is greater than 9%, it is likely that a 500 mL fluid infusion will increase cardiac output. This diagnostic threshold is higher than if only end-expiratory occlusion induced percent changes in cardiac index estimated by esophageal Doppler are taken into account.

Comparison of the diagnostic accuracy of dynamic and static preload indexes to predict fluid responsiveness in mechanically ventilated, isoflurane anesthetized dogs

ObjectiveTo compare the diagnostic accuracy of pulse pressure variation (PPV), stroke volume variation from pulse contour analysis (SVVPCA), plethysmographic variability index (PVI), central venous pressure (CVP) and global end-diastolic volume index measured by transpulmonary thermodilution (GEDVITPTD) to predict fluid responsiveness (FR) in dogs. Study designProspective study. AnimalsA group of 40 bitches (13.8–26.8 kg) undergoing ovariohysterectomy. MethodsAnesthesia was maintained with isoflurane under volume-controlled ventilation (tidal volume 12 mL kg–1; inspiratory pause during 40% of inspiratory time; inspiration:expiration ratio 1:1.5). Transpulmonary thermodilution cardiac output was recorded through a femoral artery catheter. FR was evaluated by a fluid challenge (lactated Ringer's, 20 mL kg–1 over 15 minutes) administered once (n = 21) or twice (n = 18) before surgery. Individuals were responders if stroke volume index measured by transpulmonary thermodilution increased >15% after the last fluid challenge. ResultsOf the 39 animals studied, 21 were responders and 18 were nonresponders. Area under the receiver operating characteristics curve (AUROC) was 0.976, 0.906, 0.868 and 0.821 for PPV, PVI, CVP and SVVPCA, respectively (p < 0.0001 from AUROC = 0.5). GEDVITPTD failed to predict FR (AUROC: 0.660, p = 0.078). Best cut-off thresholds discriminating responders and nonresponders, with respective zones of diagnostic uncertainty (gray zones) were: PPV >16% (15–16%), PVI >11% (10–13%), SVVPCA >10% (9–18%) and CVP ≤1 mmHg (0–3 mmHg). Percentage of animals within gray zone limits was 13% (PPV), 28% (PVI), 51% (SVVPCA) and 67% (CVP). Conclusions and clinical relevancePPV has better diagnostic accuracy to predict FR (conclusive results in nearly 90% of population) than other preload indexes in healthy dogs. When invasive blood pressure is unavailable, PVI will predict FR with reasonable accuracy (conclusive results in approximately 70% of the population). PPV and PVI values above gray zone limits (>16% and >13%, respectively) can reliably predict responders to volume expansion.

Associations of Cardiorespiratory Fitness and Adiposity With Arterial Stiffness and Arterial Dilatation Capacity in Response to a Bout of Exercise in Children.

Purpose: To investigate the associations of directly measured peak oxygen uptake ( ) and body fat percentage (BF%) with arterial stiffness and arterial dilatation capacity in children. Methods: Findings are based on 329 children (177 boys and 152 girls) aged 8-11 years. was assessed by a maximal cardiopulmonary exercise test on a cycle ergometer and scaled by lean body mass (LM). BF% and LM were measured by bioelectrical impedance. Stiffness index (measure of arterial stiffness) and change in reflection index (ΔRI, measure of arterial dilatation capacity) were assessed by pulse contour analysis. Data were analyzed by linear regression models. Results: was positively associated with ΔRI in boys adjusted for age and BF% (β = 0.169, P = .03). Further adjustments for systolic blood pressure, heart rate, and the study group had no effect on this association, but additional adjustment for clinical puberty attenuated it (β = 0.171, P = .07). BF% was inversely related to ΔRI in boys adjusted for age and (β = -0.171, P = .03). or BF% was not associated with ΔRI in girls or with stiffness index in either boys or girls. Conclusion: Increasing cardiorespiratory fitness and decreasing adiposity may improve arterial health in childhood, especially among boys.

Efficacy of Stroke Volume Variation, Cardiac Output and Cardiac Index as Predictors of Fluid Responsiveness using Minimally Invasive Vigileo Device in Intracranial Surgeries.

Introduction:Functional hemodynamic monitoring using dynamic parameters such as stroke volume variations (SVVs) based on pulse contour analysis is considered more accurate than central venous pressure and mean arterial pressure (MAP) in predicting fluid responsiveness. New device, i.e., Vigileo system, allows automatic and continuous monitoring of cardiac output (CO) based on pulse contour analysis and respiratory stroke volume.Aim:The study aims to test the above hypothesis using graded volume loading step (VLS) to assess the accuracy of SVV as a predictor of fluid responsiveness in patients undergoing intracranial surgery.Materials and Methods:After taking ethical committee approval and informed consent, 60 patients aged between 18 and 55 years belonging to the American Society of Anesthesiologists physical status Class I and II, of either sex, scheduled for brain surgery were included in the study. In this study, 5 min after intubation, with stable hemodynamics, patients received volume loading in successive steps (VLS) of 200 ml of lactated Ringer's solution until the stroke volume increased to <10%. Blood pressure (BP), heart rate (HR), stroke volume (SV), and SVV were measured before and after each VLS. Optimal preload augmentation required by each patient was measured by the number of VLS after which an increase in SV was <10%.Results:There was a significant decrease in the baseline BP and SV in responsive and nonresponsive groups for the first VLS, but there is no change in HR statistically. There was a significant change in SV after first VLS. Receiver operating characteristic analysis showed a larger area under the curve of 0.758 for SVV compared to other measured variables. The median number of VLS administered were 2 per patient equating to a mean ± SD requirement of 368 ± 176 ml of crystalloid per patient as the optimal preoperative infusion volume.Conclusion:SVV is a better predictor of preload responsiveness measured with third-generation Vigileo device when compared to BP and HR.

Postoperative Pain Assessment Model Based on Pulse Contour Characteristics Analysis.

This study aims to develop a new postoperative pain assessment model based on pulse contour analysis and to evaluate its effectiveness in postoperative pain assessment. We derived candidate features from photoplethysmography (PPG) and developed an assessment model based on multiple logistic regressions with a combination of features. This study also includes investigations into the optimal unit of analysis and number of features. For model development, PPGs obtained from 78 surgical patients with a six-min duration in pre- and post-operation conditions, including a training set of 56 pairs and a test set of 22 pairs, were used. We tested models with 5, 10, 20, 30, 40, 50, 60, 70, and 80 beats as an analysis unit, and with 1 to 8 of features for optimization, then determined 20 beats and three features to be the simplest optimal unit of analysis and number of features, respectively. The selected features were RMSSD-ACVonset/ACAbl, AV-Asys/Atotal, and SD-RS, where RMSSD-ACVonset/ACAbl is the root mean square of the successive difference of the ratio of pulse onset amplitude to the pulse onset-to-peak amplitude, AV-Asys/Atotal is the average value of a normalized systolic area of a pulse with a total pulse area, and SD-RS is the standard deviation of a rising slope of a pulse. The accuracy (AC) and the area under the curve (AUC) of the proposed model were 0.793 and 0.872 in the development set (N = 56), respectively, which were superior to those of SPI (AC: 0.643, AUC: 0.716) and ANI (AC: 0.633 AUC: 0.671). In the test set (N = 22), the AC and AUC of the proposed model were 0.712 and 0.808, respectively, which were superior to those of SPI (AC: 0.640, AUC: 0.709) and ANI (AC: 0.640, AUC: 0.680).

The utilization spectrum of cardiac output monitoring devices among anesthesiology programs across Veterans Health Administration in the United States.

Background:Electronic monitoring of physiologic variables has gained widespread support over the past decade for critical patients in the intensive care setting. Specifically, anesthesiologists have increased the emphasis and practice of hemodynamic control through monitoring cardiac output (CO). However, these physicians are presented with several options in terms of how they wish to study the trend of this physiologic parameter.Materials and Methods:A survey was distributed to 250 general and subspecialty-trained anesthesiologists. A series of questions were presented in terms of preference of patient monitoring methods requiring yes or no answers. Anesthesiologists were asked about subspecialty training, years since residency graduation, and preferences toward specific hemodynamic monitoring tools. Nonparametric statistical analysis and Chi-squared tests were used to analyze both normal and nonnormally distributed data.Results:CO monitoring devices were implemented by 106 out of 133 anesthesiologists, with 98 of these physicians utilizing CO monitoring for fluid and vasopressors response. Of the physicians implementing a monitoring device, 48 out of 107 physicians preferred pulmonary artery catheter, while pulse contour analysis was preferred by 17 anesthesiologists. An echocardiography unit was available to the department for 90 anesthesiologists, and 77 anesthesiologists were trained to use this technology for monitoring cardiac function.Conclusion:Many anesthesiologists have placed emphasis on the importance of CO monitoring within the intensive care setting. However, physicians are still faced with multiple options in terms of how they wish to specifically monitor this hemodynamic variable. Factors that influence such decisions include the time of physician's residency training along with patient and clinical case characteristics.

Goal-directed therapy during transthoracic oesophageal resection does not improve outcome: Randomised controlled trial.

Goal-directed therapy (GDT) is expected to be of highest benefit in high-risk surgery. Therefore, GDT is recommended during oesophageal resection, which carries a high risk of postoperative complications. The aim of this study was to confirm the hypothesis that GDT during oesophageal resection improves outcome compared with standard care. A randomised controlled study. Two Swedish university hospitals, between October 2011 and October 2015. Sixty-four patients scheduled for elective transthoracic oesophageal resection were randomised. Exclusion criteria included colonic interposition and significant aortic or mitral valve insufficiency. A three-step GDT protocol included stroke volume optimisation using colloid boluses as assessed by pulse-contour analysis, dobutamine infusion if cardiac index was below 2.5 l min m and norepinephrine infusion if mean arterial blood pressure was below 65 mmHg. The incidence of complications per patient at 5 and 30 days postoperatively as assessed using a predefined list. Fifty-nine patients were available for analysis. Patients in the intervention group received more colloid fluid (2190 ± 875 vs. 1596 ± 759 ml, P < 0.01) and dobutamine more frequently (27/30 vs. 9/29, P < 0.01). The median [interquartile range, IQR] incidence of complications per patient 5 days after surgery was 2 [0 to 3] in the intervention group and 1 [0 to 2] in the control group (P = 0.10), and after 30 days 4 [2 to 6] in the intervention group and 2 [1 to 4] in the control group (P = 0.10). Goal-directed therapy during oesophageal resection did not result in a reduction of the incidence of postoperative complications. Clinicaltrials.gov identifier: NCT01416077.

Noninvasive Administration of Inhaled Nitric Oxide and its Hemodynamic Effects in Patients With Acute Right Ventricular Dysfunction

The authors aimed to assess the hemodynamic effects and demonstrate the feasibility of inhaled nitric oxide (iNO) in hemodynamically unstable patients with acute right ventricular (RV) dysfunction and to explore the safety profile of this approach. Retrospective cohort study. Intensive care unit (ICU) of 2 tertiary care centers between January 2013 and 2017. All patients with RV dysfunction in whom iNO was initiated without invasive mechanical ventilation. Noninvasive administration of iNO. Eighteen patients received the intervention during the study period; 8 of these patients had a pulmonary artery catheter and 2 had a pulse contour analysis device. Median (interquartile range) iNO concentration was 20 (20-20) ppm, and therapy duration was 24 (12-46) hours. Most patients received iNO through nasal prongs (66.7%) or a high-flow nasal cannula (27.8%). Within 1 hour, iNO reduced pulmonary vascular resistance from 219.1 to 165.4 dyn•s/cm5 (n = 7; p < 0.001), mean pulmonary artery pressure from 28.4 to 25.3 mmHg (n = 8; p = 0.01), and central venous pressure from 17.5 to 13.1 mmHg (n = 16; p = 0.001). Indexed cardiac output increased from 2.0 to 2.6 L/min/m2 (n = 9; p = 0.004). ICU mortality was 27.78%, and median ICU length of stay was 7 (5-9) days. Two significant bleeding episodes requiring intervention and 1 acute kidney injury occurred during iNO therapy. No headache was reported. Noninvasively administered iNO was associated with favorable hemodynamic effects in ICU patients with acute RV dysfunction. These results suggest the safety and feasibility of this therapy for which further prospective study is warranted.

P2655Hemodynamic monitoring by pulse contour analysis during trans-catheter aortic valve implantation: a fast and easy method to optimize procedure results

P2655Hemodynamic monitoring by pulse contour analysis during trans-catheter aortic valve implantation: a fast and easy method to optimize procedure results

Hemodynamic monitoring by pulse contour analysis during trans-catheter aortic valve replacement: A fast and easy method to optimize procedure results.

Residual aortic regurgitation (AR) complicates a not negligible number of transcatheter aortic valve replacement (TAVR) procedures, and its entity is not always clear at intraprocedural angiographic and echocardiographic control. We applied a minimally invasive hemodynamic monitoring system (Pressure Recording Analytical Method, PRAM) in the setting of TAVR, with the aim of identifying parameters that may help in detection and quantification of residual AR. We performed hemodynamic monitoring with PRAM in 43 patients undergoing trans-femoral TAVR. Investigated parameters were systolic (Psys, mm Hg), diastolic (Pdia, mm Hg), mean (MAP, mm Hg) and dicrotic pressure (Pdic, mm Hg), cardiac output (CO, L/min), stroke volume (SV, mL), cardiac cycle efficiency (CCE, Units), dP/dtmax_rad (mm Hg/ms), MAP-Pdic (mm Hg). Procedural success was achieved in 86% of the patients; vascular complications occurred in 3 (6.9%), death in 2 (4.7%). Twenty (46.5%) patients had at least mild residual AR. CO, SV, CCE and dP/dtmax_rad changed significantly (p < 0.001) between baseline and end of procedure in the overall population, with more evident modifications in the subgroup without residual AR. MAP-Pdic variations were statistically significant only in the subgroup without AR (p = 0.05). TAVR determined an improvement in hemodynamic parameters such as CO, SV, CCE, dP/dtmax_rad. MAP-Pdic was able to discriminate patients with significant residual AR. Hemodynamic monitoring with PRAM system during TAVR is easy and fast to obtain and may help in clinical decision-making in controversial cases.

Pulse Contour Analysis for Prediction of Fluid Responsiveness in Preeclamptic Patients: A Case Series

Pulse Contour Analysis for Prediction of Fluid Responsiveness in Preeclamptic Patients: A Case Series

Practical impact of a decision support for goal-directed fluid therapy on protocol adherence: a clinical implementation study in patients undergoing major abdominal surgery.

The purpose of this study was to assess the effects of using a real time clinical decision-support system, "Assisted Fluid Management" (AFM), to guide goal-directed fluid therapy (GDFT) during major abdominal surgery. We compared a group of patients managed using the AFM system with a historical cohort of patients (control group) who had been managed using a manual GDFT strategy. Adherence to the protocol was defined as the relative intraoperative time spent with a stroke volume variation (SVV) < 13%. We hypothesised that patients in the AFM group would have more time during surgery with a SVV < 13% compared to the control group. All patients had a radial arterial line connected to a pulse contour analysis monitor and received a 2ml/kg/h maintenance crystalloid infusion. Additional 250ml crystalloid boluses were administered whenever measured SVV ≥ 13% in the control group, and when the software suggested a fluid bolus in the AFM group. We compared 46 AFM-guided patients to 38 controls. Patients in the AFM group spent significantly more time during surgery with a SVV < 13% compared to the control group (median 92% [82, 96] vs. 76% [54, 86]; P < 0.0005), and received less fluid overall (1775ml [1225, 2425] vs. 2350ml [1825, 3250]; P = 0.010). The incidence of postoperative complications was comparable in the two groups. Implementation of a decision support system for GDFT guidance resulted in a significantly longer period during surgery with a SVV < 13% with a reduced total amount of fluid administered. Trial registration: Clinical Trials.gov (NCT03141411).