Method for measuring jugular venous pulse with a miniature gyroscope sensor patch.

The right internal jugular vein is connected to the right atrium of the heart via the superior vena cava, and consequently its pressure, known as the jugular venous pressure or the jugular venous pulse (JVP), is an important indicator of cardiac function. The JVP can be estimated visually from the neck but it is rather difficult and imprecise. In this article we propose a method to measure the JVP using a motion sensor patch attached to the neck. The JVP signal was extracted from the sensor's 3-axes gyroscope signal and aligned with simultaneously measured ECG and seismocardiogram signals.The method was tested on 20 healthy subjects. The timings of the characteristic JVP waves were compared with the ECG R peaks and seismocardiogram heart sounds S1 and S2. The JVP was reliably measured from 18 subjects with all three waves identified. The timings of the waves were also physiologically plausible when compared to the ECG R peak and the heart sounds. Importantly, the JVP was also found to modulate with respiration, further indicating that the measured signal was indeed the JVP and not the carotid pulse.The results show that the JVP can be measured with a wearable patch-like device registering the delicate motions of the right internal jugular vein. The method has potential to be developed into a clinical tool to measure cardiac health in diseases such as heart failure and chronic obstructive pulmonary disease (COPD).Clinical relevance-The developed method could enable an affordable measurement of clinically important cardiac parameter, jugular venous pulse, as a part of a routine examination.

Assessment of venous pressure by compression sonography of the internal jugular vein during 3 days of bed rest.

Compression sonography has been proposed as a method for non-invasive measurement of venous pressures during spaceflight, but initial reports of venous pressure measured by compression ultrasound conflict with prior reports of invasively measured central venous pressure (CVP). The aim of this study is to determine the agreement of compression sonography of the internal jugular vein (IJVP) with invasive measures of CVP over a range of pressures relevant to microgravity exposure. Ten healthy volunteers (18-55 years, five female) completed two 3-day sessions of supine bed rest to simulate microgravity. IJVP and CVP were measured in the seated position, and in the supine position throughout 3 days of bed rest. The range of CVP recorded was in line with previous reports of CVP during changes in posture on Earth and in microgravity. The correlation between IJVP and CVP was poor when measured during spontaneous breathing (r = 0.29; R2  = 0.09; P = 0.0002; standard error of the estimate (SEE) = 3.0 mmHg) or end-expiration CVP (CVPEE ; r = 0.19; R2  = 0.04; P = 0.121; SEE = 3.0 mmHg). There was a modest correlation between the change in CVP and the change in IJVP for both spontaneous ΔCVP (r = 0.49; R2  = 0.24; P < 0.0001) and ΔCVPEE (r = 0.58; R2  = 0.34; P < 0.0001). Bland-Altman analysis of IJVP revealed a large positive bias compared to spontaneous breathing CVP (3.6 mmHg; SD = 4.0; CV = 85%; P < 0.0001) and CVPEE (3.6 mmHg; SD = 4.2; CV = 84%; P < 0.0001). Assessment of absolute IJVP via compression sonography correlated poorly with direct measurements of CVP by invasive catheterization over a range of venous pressures that are physiologically relevant to spaceflight. However, compression sonography showed modest utility for tracking changes in venous pressure over time. NEW FINDINGS: What is the central question of this study? Compression sonography has been proposed as a novel method for non-invasive measurement of venous pressures during spaceflight. However, the accuracy has not yet been confirmed in the range of CVP experienced by astronauts during spaceflight. What is the main finding and its importance? Our data show that compression sonography of the internal jugular vein correlates poorly with direct measurement of central venous pressures in a range that is physiologically relevant to spaceflight. However, compression sonography showed modest utility for tracking changes in venous pressure over time.

[Discussion on the zero-calibration and the zero line in the measurement of central venous pressure and invasive arterial blood pressure].

OBJECTIVE: To figure out the timing of zeroing and the location of the zero line in the central venous pressure (CVP) monitoring and invasive arterial blood pressure (IBP) monitoring, and to provide scientific and accurate data for patients management. METHODS: The liquid vessel models were used to simulate the pressure measurement process of the continuous pressure monitoring system. Based on the theory of fluid mechanics and the knowledge of blood pressure physiology and cardiovascular anatomy, the composition and influencing factors of the pressure in the fluid-filled catheter system during the zeroing and placing the transducer in the zero line of CVP and IBP, were analyzed. RESULTS: The pressure in the liquid-filled catheter system was composed of atmospheric pressure, the pressure of pumping bag, the gravity of the water column (the vertical distance between the liquid level of Murphy's dropper and pressure transducer, ΔH), and the resistance of tube wall. This pressure value is set as a pressure of 0 mmHg (1 mmHg ≈ 0.133 kPa). In the process of pressure measurement, when the pressure transducer was placed at a horizontal position of 10 cm below the highest liquid level of the vessel, the pressure measured at different catheter tip positions was all 10 cmH2O (1 cmH2O ≈ 0.098 kPa); When the pressure transducer was placed at the horizontal position of the highest liquid level of the vessel, the measured pressure is 0 mmHg. CONCLUSIONS: Zeroing should repeatedly be performed only when one or more conditions (atmospheric pressure, pressure of pumping bag, gravity of ΔH water column and resistance of tube wall) are changed. In the measurement process, the pressure transducer should be placed at the zero line position at any time to eliminate the influence of hydrostatic pressure and to ensure the objective and accurate value.

Errors in pressure measurements due to changes in pressure transducer levels during adult cardiac surgery: a prospective observational study.

BACKGROUND: Blood pressure measurement is an essential element during intraoperative patient management. However, errors caused by changes in transducer levels can occur during surgery. METHODS: This single center, prospective, observational study enrolled 25 consecutive patients scheduled for elective cardiac surgery with invasive arterial and central venous pressure (CVP) monitoring. Hydrostatic pressures caused by level differences (leveling pressure) between a reference point (on the center of the left biceps brachii muscle) and the transducers (fixed on the right side of the operating table) for arterial and central lines were continuously measured using a leveling transducer. Adjusted pressures were calculated as measured pressure - leveling pressure. Hypotension (mean arterial pressure < 80, <70, and < 60 mmHg), and CVP (< 6, ≥6 and < 15, or ≥ 15 mmHg) and pulmonary artery pressure (PAP, mean > 20 mmHg) levels were determined using unadjusted and adjusted pressures. RESULTS: Twenty-two patients were included in the analysis. Leveling pressure ≥ 3 mmHg and ≥ 5 mmHg observed at 46.0 and 18.7% of pooled data points, respectively. Determinations of hypotension using unadjusted and adjusted pressures showed disagreements ranging from 3.3 to 9.4% depending on the cutoffs. Disagreements in defined levels of CVP and PAP were observed at 23.0 and 17.2% of the data points, respectively. CONCLUSIONS: The errors in pressure measurement due to changes in transducer level were not trivial and caused variable disagreements in the determination of MAP, CVP, and PAP levels. To prevent distortions in intraoperative hemodynamic management, strategies should be sought to minimize or adjust for these errors in clinical practice. TRIAL REGISTRATION: cris.nih.go.kr (KCT0006510).

Changes in the Inferior Vena Cava Are More Sensitive Than Venous Pressure During Fluid Removal: A Proof-of-Concept Study.

BACKGROUND: Congestion is central to the pathophysiology of heart failure (HF); thus, tracking congestion is crucial for the management of patients with HF. In this study we aimed to compare changes in inferior vena cava diameter (IVCD) with venous pressure following manipulation of volume status during ultrafiltration in patients with cardiac dysfunction. METHODS AND RESULTS: Patients with stable hemodialysis and with systolic or diastolic dysfunction were studied. Central venous pressure (CVP) and peripheral venous pressure (PVP) were measured before and after hemodialysis. IVCD and PVP were measured simultaneously just before dialysis, 3 times during dialysis and immediately after dialysis. Changes in IVCD and PVP were compared at each timepoint with ultrafiltration volumes. We analyzed 30 hemodialysis sessions from 20 patients. PVP was validated as a surrogate for CVP. Mean ultrafiltration volume was 2102 ± 667 mL. IVCD discriminated better ultrafiltration volumes ≤ 500 mL or ≤ 750 mL than PVP (AUC 0.80 vs 0.62, and 0.80 vs 0.56, respectively; both P< 0.01). IVCD appeared to track better ultrafiltration volume (P< 0.01) and hemoconcentration (P< 0.05) than PVP. Changes in IVCD were of greater magnitude than those of PVP (average change from predialysis: -58 ± 30% vs -28 ± 21%; P< 0.001). CONCLUSIONS: In patients undergoing ultrafiltration, changes in IVCD tracked changes in volume status better than venous pressure.

Design and Haemodynamic Analysis of a Novel Anchoring System for Central Venous Pressure Measurement.

BACKGROUND/OBJECTIVE: In recent years, treatment of heart failure patients has proved to benefit from implantation of pressure sensors in the pulmonary artery (PA). While longitudinal measurement of PA pressure profoundly improves a clinician's ability to manage HF, the full potential of central venous pressure as a clinical tool has yet to be unlocked. Central venous pressure serves as a surrogate for the right atrial pressure, and thus could potentially predict a wider range of heart failure conditions. However, it is unclear if current sensor anchoring methods, designed for the PA, are suitable to hold pressure sensors safely in the inferior vena cava. The purpose of this study was to design an anchoring system for accurate apposition in inferior vena cava and evaluate whether it is a potential site for central venous pressure measurement. MATERIALS AND METHODS: A location inferior to the renal veins was selected as an optimal site based on a CT scan analysis. Three anchor designs, a 10-strut anchor, and 5-struts with and without loops, were tested on a custom-made silicone bench model of Vena Cava targeting the infra-renal vena cava. The model was connected to a pulsatile pump system and a heated water bath that constituted an in-vitro simulation unit. Delivery of the inferior vena cava implant was accomplished using a preloaded introducer and a dilator as a push rod to deploy the device at the target area. The anchors were subjected to manual compression tests to evaluate their stability against dislodgement. Computational Fluid Dynamics (CFD) analysis was completed to characterize blood flow in the anchor's environment using pressure-based transient solver. Any potential recirculation zones or disturbances in the blood flow caused by the struts were identified. RESULTS: We demonstrated successful anchorage and deployment of the 10-strut anchor in the Vena Cava bench model. The 10-strut anchor remained stable during several compression attempts as compared with the other two 5-strut anchor designs. The 10-strut design provided the maximum number of contact points with the vessel in a circular layout and was less susceptible to movement or dislodgement during compression tests. Furthermore, the CFD simulation provided haemodynamic analysis of the optimum 10-strut anchor design. CONCLUSIONS: This study successfully demonstrated the design and deployment of an inferior vena cava anchoring system in a bench test model. The 10-strut anchor is an optimal design as compared with the two other 5-strut designs; however, substantial in-vivo experiments are required to validate the safety and accuracy of such implants. The CFD simulation enabled better understanding of the haemodynamic parameters and any disturbances in the blood flow due to the presence of the anchor. The ability to place a sensor technology in the vena cava could provide a simple and minimally invasive approach for heart failure patients.

The Physical Examination to Assess for Anemia and Hypovolemia.

Hypovolemia develops with the loss of extracellular fluid volume or blood. Rapidly identifying hypovolemia can be lifesaving. Indicators of hypovolemia on examination include supine or postural hypotension, increase in heart rate by 30 beats per minute or severe dizziness with standing, and a decrease in central venous pressure detected on visual inspection of the jugular venous pressure or ultrasound assessment of the inferior vena cava or internal jugular veins. Other findings with utility include a dry axilla and dry oral mucosa. With chronic anemia, hemodynamic changes detectable on examination may be minimal, as the body compensates by retaining extracellular volume.

IVC measurement for the noninvasive evaluation of central venous pressure.

Central venous pressure (CVP) is one of only a handful of variables that can be used to assess a patient's volume status to attempt to optimize stroke volume. The gold standard method for assessing CVP is though pulmonary artery catheterization, which is invasive and risks severe complications such as pneumothorax and cardiac conduction abnormalities. Current noninvasive methods for estimating CVP such as jugular venous pressure assessment are imperfect with wide inter-examiner variability. The inferior vena cava (IVC) is a highly compliant vessel that uniquely does not constrict in response to hypovolemia, making it an ideal, noninvasive surrogate for the estimation of CVP. A range of IVC indices including minimum and maximum IVC diameter and fraction of IVC collapse with inspiration (known as collapsibility index) have been studied with highly variable results that range from excellent to poor correlation between these values and CVP. Despite this inconsistency in findings, multiple schemes have been proposed to attempt to estimate CVP from IVC measurements, but when prospectively tested, none has been shown to be accurate. Since the most recent 2015 American Society of Echocardiography guidelines, multiple studies have identified unique ways of improving the accuracy of IVC measurement, which could translate into better CVP estimation. The goal of this review is to summarize the many, often conflicting studies that exist in this area, and provide recommendations for future studies based on our findings.

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

Introduction: 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. Methods: 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. Results: 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). Conclusion: 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.

Effect of Blood Flow Rate on the Accuracy of Central Venous Pressure Measurement during Continuous Renal Replacement Therapy.

BACKGROUND: The objective of this study was to study the influence of extracorporeal blood flow rate (BFR) on the accuracy of central venous pressure (CVP) measurement during continuous renal replacement therapy (CRRT). METHODS: Eligible patients were randomly divided into 3 groups based on the location of catheters used for their CRRT and CVP measurement. CVP levels measured at increased extracorporeal BFR (from 0 to 300 mL/min) in the normal and reverse positions of inlet and outlet lines connected to the CV catheter (CVC) in the course of the CRRT session were collected. RESULTS: CVP levels measured at different extracorporeal BFRs did not significantly differ between and among the 3 groups. Inversion of inlet and outlet lines connected to the catheters did not affect the accuracy of CVP measurement. BFR had a negative correlation with inflow/access pressure but a positive correlation with outflow/return pressure. Neither inflow pressure nor outflow pressure was correlated with CVP. CONCLUSIONS: Extracorporeal BFR has no influence on the accuracy of CVP measurement during CRRT with the net machine balance adjusted to zero regardless of the location of the catheter and the connection method between catheters and CRRT lines. Thus, CRRT does not need to be discontinued to obtain an accurate CVP measurement.

Is measurement of central venous pressure required to estimate systemic vascular resistance? A retrospective cohort study.

BACKGROUND: The clinical range of central venous pressure (CVP) (typically 5 to 15 mmHg) is much less than the range of mean arterial blood pressure (60 to 120 mmHg), suggesting that CVP may have little impact on estimation of systemic vascular resistance (SVR). The accuracy and feasibility of using an arbitrary CVP rather than actual CVP for the estimation of SVR during intraoperative period is not known. METHODS: Using vital records obtained from patients who underwent neurological and cardiac surgery, the present study retrospectively calculated SVR using fixed values of CVP (0, 5, 10, 15, and 20 mmHg) and randomly changing values of CVP (5 to 15 mmHg) and compared these calculated SVRs with actual SVR, calculated using actual CVP. Differences between actual SVR and SVRs based on fixed and random CVPs were quantified as root mean square error (RMSE) and mean absolute percentage error (MAPE). Bland-Altman analysis and four-quadrant plot analysis were performed. RESULTS: A total of 34 patients are included, including 18 who underwent neurosurgery and 16 who underwent cardiac surgery; 501,380 s (139.3 h) of data was analyzed. The SVR derived from a fixed CVP of 10 mmHg (SVRf10) showed the highest accuracy (RMSE: 115 and 104 [dynes/sec/cm- 5] and MAPE: 6.3 and 5.7% in neurological and cardiac surgery, respectively). The 95% limits of agreement between SVRf10 and actual SVR were - 208.5 (95% confidence interval [CI], - 306.3 to - 148.1) and 242.2 (95% CI, 181.8 to 340.0) dynes/sec/cm- 5 in neurosurgery and - 268.1 (95% CI, - 367.5 to - 207.7) and 163.2 (95% CI, 102.9 to 262.6) dynes/sec/cm- 5 in cardiac surgery. All the SVRs derived from the fixed CVPs (regardless of its absolute value) showed excellent trending ability (concordance rate > 0.99). CONCLUSIONS: SVR can be estimated from a fixed value of CVP without causing significant deviation or a loss of trending ability. However, caution is needed when using point estimates of SVR when the actual CVP is expected to be out of the typical clinical range. TRIAL REGISTRATION: This study was registered Clinical Research Information Service, a clinical trial registry in South Korea ( KCT0006187 ).

Venous Properties in a Fontan Patient with Successful Remission of Protein-Losing Enteropathy.

We present the case of a 1-year-old boy who developed protein-losing enteropathy (PLE) within 2 months of a fenestrated Fontan procedure. His fenestration rapidly closed despite bilateral pulmonary stenosis (BPS). Subsequent to PLE onset, both fenestration and the bilateral pulmonary artery were reconstructed, and the patient's PLE had been in remission, with additive use of medications, for more than 2 years. Notably, although fenestration closed again and central venous pressure (CVP) reduction was minimal, the surrogates of venous return resistance were markedly suppressed as shown by increased blood volume, reduced estimated mean circulatory filling pressure, and suppressed CVP augmentation against a contrast agent. Taken together, dynamic characteristics of venous stagnation, rather than the absolute value of CVP, were ameliorated by the pulmonary reconstruction and use of medications, suggesting a significant role of venous property in the physiology of PLE. In addition, simultaneous measures of CVP and ventricular end-diastolic pressure during the abdominal compression procedure suggested a limited therapeutic role of fenestration against PLE in this patient.

Four-quadrant visualization of systemic circulatory equilibrium: right ventricular failure after left ventricular assist device implantation.

Right ventricular failure (RVF) is a serious adverse event after left ventricular assist device (LVAD) implantation but difficult to be characterized. This study aimed to visualize the dynamic circulatory equilibrium of acute RVF after LVAD implantation using a new four-quadrant diagram constructed by 1) cardiac function with central venous pressure (CVP) and cardiac index (CI) axes, 2) arterial vascular resistance with CI and mean blood pressure (mBP) axes, 3) pressure-diuretic function with mBP and net urinary sodium output (net U-Na) axes, and 4) venous compliance with net U-Na and CVP axes. Twenty LVAD patients were stratified into two groups, group S (≤10 days) and group L (>10 days), according to duration of postoperative inotropic support. The preoperative equilibrium loops were small in both groups. In the early postoperative phase, the loop in group S became dramatically enlarged to the left and upward, indicating increased CVP and CI by LVAD support. In group L, however, augmentation of CI was smaller despite similarly increased CVP, and net U-Na was decreased despite increased mBP. In the late postoperative phase, the equilibrium loop in group L recovered as similar to that seen in group S. Thus, acute RVF, as shown in group L, was characterized by the shape of the loop constructed by marked increased CVP, a relatively small increase in CI, and concomitant impairment of pressure natriuresis. In conclusion, the novel four-quadrant presentation of systemic circulatory equilibrium provides clear visualization of RVF after LVAD implantation, thus serving as a useful guide for prompt and optimal management.NEW & NOTEWORTHY Systemic circulatory dynamics are regulated by various negative feedback systems, including cardiac, arterial, venous, and renal functions, as well as autonomic nervous systems. The present novel four-quadrant presentation of their functions allows clear visualization of dynamic organ-to-organ interactions that can lead to a new circulatory equilibrium after therapeutic intervention. This new system physiological framework can serve as a useful guide for prompt and optimal management of circulatory malfunction.

Estimation of change in pleural pressure in assisted and unassisted spontaneous breathing pediatric patients using fluctuation of central venous pressure: A preliminary study.

BACKGROUND: It is important to evaluate the size of respiratory effort to prevent patient self-inflicted lung injury and ventilator-induced diaphragmatic dysfunction. Esophageal pressure (Pes) measurement is the gold standard for estimating respiratory effort, but it is complicated by technical issues. We previously reported that a change in pleural pressure (ΔPpl) could be estimated without measuring Pes using change in CVP (ΔCVP) that has been adjusted with a simple correction among mechanically ventilated, paralyzed pediatric patients. This study aimed to determine whether our method can be used to estimate ΔPpl in assisted and unassisted spontaneous breathing patients during mechanical ventilation. METHODS: The study included hemodynamically stable children (aged <18 years) who were mechanically ventilated, had spontaneous breathing, and had a central venous catheter and esophageal balloon catheter in place. We measured the change in Pes (ΔPes), ΔCVP, and ΔPpl that was calculated using a corrected ΔCVP (cΔCVP-derived ΔPpl) under three pressure support levels (10, 5, and 0 cmH2O). The cΔCVP-derived ΔPpl value was calculated as follows: cΔCVP-derived ΔPpl = k × ΔCVP, where k was the ratio of the change in airway pressure (ΔPaw) to the ΔCVP during airway occlusion test. RESULTS: Of the 14 patients enrolled in the study, 6 were excluded because correct positioning of the esophageal balloon could not be confirmed, leaving eight patients for analysis (mean age, 4.8 months). Three variables that reflected ΔPpl (ΔPes, ΔCVP, and cΔCVP-derived ΔPpl) were measured and yielded the following results: -6.7 ± 4.8, - -2.6 ± 1.4, and - -7.3 ± 4.5 cmH2O, respectively. The repeated measures correlation between cΔCVP-derived ΔPpl and ΔPes showed that cΔCVP-derived ΔPpl had good correlation with ΔPes (r = 0.84, p< 0.0001). CONCLUSIONS: ΔPpl can be estimated reasonably accurately by ΔCVP using our method in assisted and unassisted spontaneous breathing children during mechanical ventilation.

Pressão arterial central e risco cardiovascular / Central blood pressure and cardiovascular risk

Pressão Central, como o nome indica, é uma medida hemodinâmica semelhante a pressão arterial convencional porém avaliada de forma indireta por equipamento especifico, que avalia estes parâmetros na saída do sangue na raiz da aorta. Esta medida tem uma maior confiabilidade pois prediz de forma mais acurada os riscos de adoecimento e morte cardiovascular. Isto ocorre, pois a a onda de pulso (OP) ao percorrer os trajetos arteriais sofrem ampliações e importantes modificações no seu contorno deformando o valor original. Embora seja mais precisa em valores, ainda não é usado de rotina na pratica clinica por razoes de custos dos seus equipamentos e provavelmente por exigir habilidades maiores que as medidas captadas pelo equipamentos de mensuração periférica

Central pressure, as the name implies, is a hemodynamic measure similar to conventional blood pressure, but indirectly assessed by specific equipment, which evaluates these parameters at the blood outlet at the root of the aorta. This measure has greater confidence because it more accurately predicts the risks of cardiovascular disease and death. This occurs because the pulse wave (OP) when traversing the arterial paths provides enlargements and modifications in its contour, deforming the original value. Although it is more precise in terms of values, it is not yet routinely used in clinical practice for reasons of the cost of its equipment and probably because it requires greater needs than measures captured by peripheral measurement equipment

Hemodynamic Management During Kidney Transplantation: A French Survey.

BACKGROUND: Hypovolemia or excess fluid load during kidney transplantation may have detrimental effects on the recipient and graft. The aim of our survey was to examine hemodynamic monitoring during kidney transplantation (KT) in French KT centers. BASIC PROCEDURES: The online survey covered the organization of anesthesia, the type of hemodynamic monitoring available in each center, the frequency of use of each hemodynamic parameter, and the hemodynamic algorithm used to manage fluid administration. MAIN FINDINGS: Twenty-four centers answered the survey (70% of all the 34 French KT centers) and reported performing 2029 KTs in 2016. Anesthesia for KT was performed either by a general team (n = 12, 48%) or less often, by a specific team during open hours (n = 7, 28%), a specific 24-hour/24-hour team (n = 5, 20%), or an emergency team (n = 1, 4%). The centers reported that up to 8 different hemodynamic monitoring techniques were available for KT. Central venous pressure (CVP) is the most frequently used hemodynamic parameter (1278 KT, 63%). Among the 17 centers using CVP monitoring, 9 had no specific algorithm and the other 8 centers used a different algorithm to manage fluids with CVP. The total fluids administered during KT varied from 1000 mL to 3500 mL. CONCLUSIONS: CVP was still the main hemodynamic parameter used in France during KT in 2016. Our results suggest that a large randomized controlled trial should be performed to specifically address the question of hemodynamic management during KT.

[Evaluation of infrahepatic inferior vena cava clamping in robot-assisted laparoscopic liver resection].

Objective: To evalutate the safety and efficacy of infrahepatic inferior vena cava clamping robot-assisted laparoscopic liver resection. Methods: All data about 24 patients with robotic liver resection at Hepatic Surgery Center,Tongji Hospital,Tongji Medical College,Huazhong University of Science and Technology between February 2015 and December 2017 were collected and analyzed. These patients were divided into two groups based on different methods to decrease central venous pressure. Eight patients(6 males and 2 females,aged 49 years(range:50 to 56 years)) were applied with infrahepatic inferior vena cava clamping,and the other 16 matched cases (15 males and 1 female,aged 53 years(range:38 to 69 years)) were categorized into lowering central venous pressure group. Intraoperative blood loss,blood transfusion,intraoperative hemodynamic parameters,postoperative complications,and renal function were compared by t-test,non-parametric test,χ2 test,or Fisher exact test. Results: There was significantly difference in the intraoperative blood loss between the infrahepatic vena cava clamping group and the lowering central venous group(200(220) ml (range:100 to 400 ml) vs. 750(800) ml (range:100 to 2 000 ml),Z=‒2.169,P=0.030). The clamping time of portal triad and infrahepatic inferior vena cava were 24 (18) minutes and 29 (20) minutes in the infrahepatic inferior vena cava clamping group, and portal triad clamping time was 23 (23) minutes in the low central venous group. There was no significant difference between the two groups (Z=‒0.323, P=0.747). There was no intraoperative blood transfusion in the infrahepatic inferior vena cava clamping group, and 5 cases in the low central venous group, with a transfusion volume of 1.5(1.5)U. The difference between the two groups was statistically significant (Z=‒3.353, P=0.001). However, the mean arterial pressure in the infrahepatic vena cava clamping group decreased from (88.6±4.9) mmHg to (67.4±3.8) mmHg(1 mmHg=0.133 kPa), which was lower than that of lowering central venous group (72.4±3.3) mmHg (t=2.315,P=0.003). And there were no significant differences related to postoperative complications rate or hepatic and renal function in both groups. Conclusion: The infrahepatic inferior vena cava technology is safe and feasible to decrease central venous pressure during robotic liver resections,which will not affect the recovery of hepatic and renal functions.

Relation of Peripheral Venous Pressure to Central Venous Pressure in Patients With Heart Failure, Heart Transplant, and Left Ventricular Assist Device.

Peripheral venous pressure (PVP) monitoring is a noninvasive method to assess volume status. We investigated the correlation between PVP and central venous pressure (CVP) in heart failure (HF), heart transplant (HTx), and left ventricular assist device (LVAD) patients undergoing right heart catheterization (RHC). A prospective, cross-sectional study examining PVP in 100 patients from October 2018 to January 2020 was conducted. The analysis included patients undergoing RHC admitted for HF, post-HTx monitoring, or LVAD hemodynamic testing. Sixty percent of patients had HF, 30% were HTx patients, and 10% were LVAD patients. The mean PVP was 9.4 ± 5.3 mm Hg, and the mean CVP was 9.2 ± 5.8 mm Hg. The PVP and CVP were found to be highly correlated (r = 0.93, p < 0.00001). High correlation was also noted when broken down by HF (r = 0.93, p < 0.00001), HTx (r = 0.93, p < 0.00001), and LVAD groups (r = 0.94, p < 0.00005). In conclusion, there is a high degree of correlation between PVP and CVP in HF, HTx, and LVAD patients. PVP measurements can be used as a rapid, reliable, noninvasive estimate of volume status in these patient populations.

Venous Waveform Analysis Correlates With Echocardiography in Detecting Hypovolemia in a Rat Hemorrhage Model.

BACKGROUND: Assessing intravascular hypovolemia due to hemorrhage remains a clinical challenge. Central venous pressure (CVP) remains a commonly used monitor in surgical and intensive care settings for evaluating blood loss, despite well-described pitfalls of static pressure measurements. The authors investigated an alternative to CVP, intravenous waveform analysis (IVA) as a method for detecting blood loss and examined its correlation with echocardiography. METHODS: Seven anesthetized, spontaneously breathing male Sprague Dawley rats with right internal jugular central venous and femoral arterial catheters underwent hemorrhage. Mean arterial pressure (MAP), heart rate, CVP, and IVA were assessed and recorded. Hemorrhage was performed until each rat had 25% estimated blood volume removed. IVA was obtained using fast Fourier transform and the amplitude of the fundamental frequency (f1) was measured. Transthoracic echocardiography was performed utilizing a parasternal short axis image of the left ventricle during hemorrhage. MAP, CVP, and IVA were compared with blood removed and correlated with left ventricular end diastolic area (LVEDA). RESULTS: All 7 rats underwent successful hemorrhage. MAP and f1 peak amplitude obtained by IVA showed significant changes with hemorrhage. MAP and f1 peak amplitude also significantly correlated with LVEDA during hemorrhage (R = 0.82 and 0.77, respectively). CVP did not significantly change with hemorrhage, and there was no significant correlation between CVP and LVEDA. CONCLUSIONS: In this study, f1 peak amplitude obtained by IVA was superior to CVP for detecting acute, massive hemorrhage. In addition, f1 peak amplitude correlated well with LVEDA on echocardiography. Translated clinically, IVA might provide a viable alternative to CVP for detecting hemorrhage.