Changes In Central Venous Pressure Research Articles

Dynamic Narrowing of the Diaphragmatic Vena Cava in Ovis aries.

Dorset sheep (Ovis aries) are common models in translational cardiovascular research due to physiologic and anatomic similarities to humans. While employing ovine subjects to study single-ventricle physiology, we repeatedly observed position-based changes in central venous pressure (CVP) which could not be explained by hydrostatic (gravitational) effects. Inferior vena cava (IVC) narrowing or compression has been demonstrated in numerous species, and we hypothesised that this phenomenon might explain our observations in O. aries. This study aimed to characterise position-dependent morphology of the IVC in O. aries using catheter-based hemodynamic and dimensional measurements, three-dimensional MRI reconstruction and histological analysis. Baseline measurements revealed a significant reduction in IVC dimensions at the level of the diaphragm (dVC) compared to the abdominal vena cava (aVC) and thoracic vena cava (tVC). We also observed a transdiaphragmatic pressure gradient along the IVC, with higher pressures in the aVC compared to the tVC. We found that variation of position and fluid status altered IVC haemodynamics. Histological data showed variable muscularity along the length of the IVC, with greater smooth muscle content in the aVC than the tVC. These findings will improve understanding of baseline ovine physiology, help refine experimental protocols and facilitate the translation of findings to the clinic.

Estimating the change in pleural pressure using the change in central venous pressure in various clinical scenarios: a pig model study

BackgroundWe have previously reported a simple correction method for estimating pleural pressure (Ppl) using central venous pressure (CVP). However, it remains unclear whether this method is applicable to patients with varying levels of intravascular volumes and/or chest wall compliance. This study aimed to investigate the accuracy of our method under different conditions of intravascular volume and chest wall compliance.ResultsTen anesthetized and paralyzed pigs (43.2 ± 1.8 kg) were mechanically ventilated and subjected to lung injury by saline lung lavage. Each pig was subjected to three different intravascular volumes and two different intraabdominal pressures. For each condition, the changes in the esophageal pressure (ΔPes) and the estimated ΔPpl using ΔCVP (cΔCVP-derived ΔPpl) were compared to the directly measured change in pleural pressure (Δd-Ppl), which was the gold standard estimate in this study. The cΔCVP-derived ΔPpl was calculated as κ × ΔCVP, where “κ” was the ratio of the change in airway pressure to the change in CVP during the occlusion test. The means and standard deviations of the Δd-Ppl, ΔPes, and cΔCVP-derived ΔPpl for all pigs under all conditions were 7.6 ± 4.5, 7.2 ± 3.6, and 8.0 ± 4.8 cmH2O, respectively. The repeated measures correlations showed that both the ΔPes and cΔCVP-derived ΔPpl showed a strong correlation with the Δd-Ppl (ΔPes: r = 0.95, p < 0.0001; cΔCVP-derived ΔPpl: r = 0.97, p < 0.0001, respectively). In the Bland–Altman analysis to test the performance of the cΔCVP-derived ΔPpl to predict the Δd-Ppl, the ΔPes and cΔCVP-derived ΔPpl showed almost the same bias and precision (ΔPes: 0.5 and 1.7 cmH2O; cΔCVP-derived ΔPpl: − 0.3 and 1.9 cmH2O, respectively). No significant difference was found in the bias and precision depending on the intravascular volume and intraabdominal pressure in both comparisons between the ΔPes and Δd-Ppl, and cΔCVP-derived ΔPpl and Δd-Ppl.ConclusionsThe CVP method can estimate the ΔPpl with reasonable accuracy, similar to Pes measurement. The accuracy was not affected by the intravascular volume or chest wall compliance.

Assessment of venous pressure by compression sonography of the internal jugular vein during 3days 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 (18-55years, 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 3days 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)=3.0mmHg) or end-expiration CVP (CVPEE ; r=0.19; R2 =0.04; P=0.121; SEE=3.0mmHg). 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 (3.6mmHg; SD=4.0; CV=85%; P<0.0001) and CVPEE (3.6mmHg; 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.

Real-world safety and effectiveness of inhaled nitric oxide therapy for pulmonary hypertension during the perioperative period of cardiac surgery: a post-marketing study of 2817 patients in Japan

ObjectiveTo evaluate the real-world safety and effectiveness of inhaled nitric oxide (INOflo® for Inhalation 800 ppm) for perioperative pulmonary hypertension associated with cardiac surgery in Japan.MethodsThis was a prospective, non-interventional, all-case, post-marketing study of pediatric and adult patients who received perioperative INOflo with cardiac surgery from November 2015–December 2020. Safety and effectiveness were monitored from INOflo initiation to 48 h after treatment completion or withdrawal. Safety outcomes included adverse drug reactions, blood methemoglobin concentrations, and inspired nitrogen dioxide concentrations over time. Effectiveness outcomes included changes in central venous pressure among pediatrics, mean pulmonary arterial pressure among adults, and the partial pressure of arterial oxygen/fraction of inspired oxygen ratio (PaO2/FiO2) in both populations.ResultsThe safety analysis population included 2,817 Japanese patients registered from 253 clinical sites (pediatrics, n = 1375; adults, n = 1442). INOflo was generally well tolerated; 15 and 20 adverse drug reactions were reported in 14 pediatrics (1.0%) and 18 adults (1.2%), respectively. No clinically significant elevations in blood methemoglobin and inspired nitrogen dioxide concentrations were observed. INOflo treatment was associated with significant reductions in both central venous pressure among pediatrics and mean pulmonary arterial pressure among adults, and significant improvements in PaO2/FiO2 among pediatrics and adults with PaO2/FiO2 ≤ 200 at baseline.ConclusionsPerioperative INOflo treatment was a safe and effective strategy to improve hemodynamics and oxygenation in patients with pulmonary hypertension during cardiac surgery. These data support the use of INOflo for this indication in Japanese clinical practice.

Effect of Exogenous Albumin Replacement on Plasma Colloid Osmotic Pressure in Severe Preeclampsia: A Case-control Study

Background: In preeclampsia, hypoalbuminemia reduces plasma colloid osmotic pressure (PCOP) and favors capillary leakage. Replacement with exogenous albumin is a therapeutic alternative.&#x0D; Objective: to determine the effect of exogenous albumin replacement on PCOP in patients with severe preeclampsia (SP).&#x0D; Methods: A case-control study was carried out in 76 pregnant patients with SP from the Intensive Care Unit (ICU). The case group (n=38) received 0.9% saline solution 1000 ml every 8 hours and 25% albumin 50 ml every 8 hours and the control group (n=38) only received 0.9% saline solution 1000 ml every 8 hours. Plasma albumin concentrations, PCOP, hemodynamic and laboratory data from admission (baseline measurement) vs discharge from the ICU (final measurement) of both groups were compared.&#x0D; Statistical Analysis: the data was analyzed with descriptive statistics, paired Student's t-test and Pearson's correlation coefficient with the statistical program SPSS® version 20. The p value &lt;0.05 was significant.&#x0D; Results: A significant decrease in plasma albumin was found (case group 2.72±0.44 vs 2.45±0.48 g/dL, p=0.0141; control group 3.06±0.33 vs 2.58±0.29 g/dL, p=0.0431). PCOP was also significantly reduced (case group 18.44±2.92 vs 16.82±2.70 mmHg, p=0.0210; control group 20.38±2.28 vs 17.46±1.96 mmHg, p=0.0763). The group of cases showed an increase in uresis (p=0.0326), but without changes in central venous pressure (p=0.3246) and serum creatinine (p=0.9515). With this evidence the recommendation is that its use in patients with preeclampsia should be reserved for the experience of the medical team.&#x0D; Conclusion: Exogenous albumin replacement therapy did not correct the PCOP values or the blood albumin concentration.

Liver Fibrosis Markers Represent Central Venous Pressure in Post-pubertal Patients With Congenital Heart Disease.

Background Central venous pressure (CVP) is one of the most important hemodynamic parameters in patients with congenital heart disease (CHD). In adults, it is well-known that liver fibrosis markers reflect CVP, but this is notwell-understood in children. We investigated the liver fibrosis markers in pediatric CHD patients and their ability to predict CVP. Methods We studied 160 patients who underwent cardiac catheterization in our hospital between January 2017 and December 2020. The levels of the fibrotic markers, including type IV collagen 7s, procollagen type III peptide, and hyaluronic acid, were measured. Results Procollagen type III peptide was markedly elevated in infants younger than one year of age. From one to 15 years of age, it was slightly lower than in the infant group, with a peak at around 10 years of age. In the age group of 16 years and older, most of its values were generally high. Type IV collagen 7s and hyaluronic acid levels were high in infants, with no significant differences at later ages. Procollagen type III peptide and hyaluronic acid showed no significant correlation with CVP in any of the age groups, whereas type IV collagen 7s significantly correlated with CVP in the age group above one yearold. Conclusions We found that elevated liver fibrosis markers, particularly type IV collagen 7s, correlated with central venous pressure in CHD patients older than one year. Measurement of liver fibrosis markers may allow the early detection of changes in CVP and liver function in patients with CHD.

A Novel Spectral Index for Tracking Preload Change from a Wireless, Wearable Doppler Ultrasound.

A wireless, wearable Doppler ultrasound offers a new paradigm for linking physiology to resuscitation medicine. To this end, the image analysis of simultaneously-acquired venous and arterial Doppler spectrograms attained by wearable ultrasound represents a new source of hemodynamic data. Previous investigators have reported a direct relationship between the central venous pressure (CVP) and the ratio of the internal jugular-to-common carotid artery diameters. Because Doppler power is directly related to the number of red cell scatterers within a vessel, we hypothesized that (1) the ratio of internal jugular-to-carotid artery Doppler power (V/APOWER) would be a surrogate for the ratio of the vascular areas of these two vessels and (2) the V/APOWER would track the anticipated CVP change during simulated hemorrhage and resuscitation. To illustrate this proof-of-principle, we compared the change in V/APOWER obtained via a wireless, wearable Doppler ultrasound to B-mode ultrasound images during a head-down tilt. Additionally, we elucidated the change in the V/APOWER during simulated hemorrhage and transfusion via lower body negative pressure (LBNP) and release. With these Interesting Images, we show that the Doppler V/APOWER ratio qualitatively tracks anticipated changes in CVP (e.g., cardiac preload) which is promising for both diagnosis and management of hemodynamic unrest.

Value of Central Venous Pressure Monitoring in the Patients with Sepsis-Associated Acute Kidney Injury.

Although the measurement of central venous pressure (CVP) is a common clinical tool, the role of CVP monitoring in the outcome of sepsis is controversial because threshold values of CVP are uncertain, and there are only limited data on short-term survival of patients with septic acute kidney injury (AKI). This retrospective cohort study was based on the Medical Information Mart for Intensive Care IV (MIMIC-IV) database (source of the training dataset). Multivariate regression analysis was performed to clarify the relation between CVP measurement and clinical outcomes, and a univariate regression model after propensity score matching was utilized to validate our findings. A mortality prediction model for septic AKI and a risk stratification scoring approach were developed, and the emergency intensive care unit (eICU) database was used for external validation. Of the 9170 patients in the training set, 2446 (26.7%) underwent CVP measurement. No significant association was found between CVP monitoring and 28-day mortality among patients with septic AKI (odds ratio = 0.479; 95% confidence interval 0.213-1.076, P = 0.075), even after adjustments (propensity score matching; P = 0.178). Length of ICU stay and hospital stay was markedly reduced in patients undergoing CVP measurement within 3 hours (median 6.2 and 10.9 days, respectively, P < 0.001). The addition of the mean perfusion pressure initial, CVP, and the magnitude of the CVP change within 48 hours to the model significantly increased model discrimination (area under the receiver operating characteristic curve: 0.867 and 0.780, respectively, P < 0.001). These findings suggest that CVP measurement alone has little effect on the outcome of septic AKI. Nonetheless, initial CVP levels and the dynamic changes in CVP within the first 48 hours after ICU admission and the mean perfusion pressure initial can improve the accuracy of outcome prediction models.

Effect of positive end-expiratory pressure on central venous pressure in the closed and open thorax

Objective. The magnitude and mechanism of the rise of central venous pressure (CVP) after positive end-expiratory pressure (PEEP) among patients with cardiac disease is poorly understood. Therefore, the study aimed to compare the magnitude of change in CVP after PEEP in patients with TR (tricuspid regurgitation), high CVP, and high PCWP (pulmonary capillary wedge pressure) and in those with no TR, low CVP, and low PCWP. Additionally, we hypothesized that PEEP in the open thorax would also lead to a rise in CVP. Approach. This prospective, quasi-experimental study was conducted in patients undergoing cardiac surgery. Three consecutive readings of variables were obtained at 1 min intervals after PEEP (5 and 10 cm H2O) application in the closed and open thorax. Patients were stratified a priori into low CVP (<10 cm H2O) and high CVP (≥10 cm H2O), no TR and TR, and low PCWP (<15 mm Hg) and high PCWP (≥15 mm Hg) in the closed and open thorax. Main Results. Sixty-two patients were eligible for final analysis. The mean difference (MD) in ΔCVP (CVP10 cm H2O of PEEP—CVP zero end-expiratory pressure) was 2.33 ± 1.13 (95% CI, 2.04–2.62, P = 0.000) and 1.02 ± 0.77 (95% CI, 0.82–1.22, P = 0.000) in the closed and open thorax, respectively. The increase in CVP was higher among patients who had a lower CVP (2.64 ± 0.9 mm Hg versus 1.45 ± 1.17 mm Hg; p=0.000), in patients without TR (2.64 ± 0.97 mm Hg versus 2.14 ± 1.2 mm Hg, p=0.09) and in patients with a lower PCWP (2.4 ± 0.9 mm Hg versus 2.3 ± 1.4 mm Hg, p=0.67) at 10 cm H2O PEEP in the closed thorax. Significance. The rise in CVP was higher among patients without TR, low CVP, and low PCWP. Zero intrathoracic pressure in the open thorax did not abolish the effect of PEEP on CVP rise altogether.

Bedside ultrasound to assess acute central venous pressure change during treatment of decompensated heart failure.

Accurate volume status assessment is crucial for the treatment of acute decompensated heart failure (ADHF). Volume status assessment by physical exam is often inaccurate, necessitating invasive measurement with right heart catheterization (RHC), which carries safety, pragmatic (scheduling, holding anticoagulants, etc.), and financial burdens. Therefore, a reliable, non-invasive, cost-effective alternative is desired. Previously, we developed an ultrasound (US) based technique to measure internal jugular vein (IJV) compliance during RHC which was used for single time point central venous pressure (CVP) predictions. We now aim to apply this technique to track acute changes in CVP during diuresis for ADHF in patients with an in-dwelling pulmonary artery catheter (PAC). We used an observational, prospective study design and recruited 15 patients from the cardiac critical unit (CCU) being treated for ADHF (systolic or diastolic) with intravenous (IV) diuretics with/without inotropic agents who underwent Swan- Ganz catheter/PAC insertion for continuous CVP monitoring. 13 of 15 patients received milrinone infusions. US images of the IJV were obtained at end-expiration and during the strain phase of Valsalva at multiple 2-3 hours intervals. Change in IJV cross-sectional area (CSA) (ImageJ) was used as a measure of IJV compliance. Patients unable to perform the Valsalva maneuver were excluded. Calculated percentage change (%Δ) in CSA of IJV was plotted against CVP. An inverse relationship was observed between CVP and %Δ in CSA of IJV. The data was fit with a polynomial regression curve (R2=0.36, root mean square error=3.19). Fivefold cross-validation showed a stable model for predicting CVP based on CSA (R2=0.31, root mean square error=3.18). Serial portable US assessment of IJV compliance can act as a surrogate measure of CVP and, therefore, can provide reliable information on acute hemodynamic changes in ADHF.

P218 POTENTIAL ROLE OF NITROGLYCERIN FOR DIURETIC RESISTANCE IN ACUTE DECOMPENSATED HEART FAILURE: A PROOF OF CONCEPT STUDY

Abstract Background Congestion is a major determinant of end–organ dysfunction and diuretic resistance in acute decompensated heart failure (ADHF). Vasodilator therapy with nitroglycerin may help treat misdistribution of blood volume, reduce intra–abdominal pressure and improve end–organ function by recruiting capacitance veins. We assessed the role of intravenous nitroglycerin on top of maximal medical therapy to overcome diuretic resistance in ADHF patients. Methods This is a monocentric prospective study including patients with ADHF, systolic dysfunction (left ventricular ejection fraction [LVEF]&amp;lt;35%), persistent moderate–to–severe congestion and oliguria (&amp;lt;0.5 ml/Kg/h) despite high dose intravenous furosemide (&amp;gt;250 mg/die) plus a second diuretic (metolazone and/or acetazolamide). Exclusion criteria were systolic blood pressure &amp;lt; 90mmHg and eGFR &amp;lt; 20 ml/min/1.73m2. Intravenous nitroglycerin was added and uptitrated to the maximum tolerated dose while keeping the other treatments unchanged for at least 24 hours. The primary endpoint was change in urine output at 24 hours (T1) and 72 hours (T3) after nitroglycerin initiation compared to baseline (T0). Secondary endpoints were changes in central venous pressure (CVP), creatinine and total bilirubin. Results We enrolled 17 consecutive patients between March 2020 and October 2021. Mean age was 63±14 years, mean LVEF 31±15%, mean tricuspid annular plane systolic excursion 14.5±4 mm and mean eGFR 41.7±27.3 ml/min/1.73m2. 13 (76%) patients showed a cold profile; among them, 9 (69%) were on dobutamine, 5 (38%) on adrenaline and 3 (23%) on dopamine. At study enrolment all patients were receiving high dose intravenous furosemide (535±395mg/die), 8 (47%) sodium nitroprusside (0.3±0.5y/Kg/min), 9 (53%) metolazone (5mg/die) and 8 (47%) acetazolamide (250 mg/die). Urine output was significantly higher both at T1 and T3 compared to T0 (192±140ml/h vs 50±34ml/h, p &amp;lt; 0.001, and 153±87ml/h vs 50±34ml/h, p &amp;lt; 0.001, respectively; p for overall comparison&amp;lt;0.001). Also, a significant reduction of CVP was found at T1 and T3 compared to T0 (14±6mmHg vs 19±3mmHg, p = 0.025, and 12±5mmHg vs 19±3mmHg, p = 0.022, respectively; p for overall comparison=0.039). No significant changes of creatinine and total bilirubin were reported. Conclusions In this cohort of ADHF patients with diuretic resistance, adding nitroglycerin on top of maximal treatment yielded a potential benefit by significantly increasing hourly urine output whilst reducing CVP.

The utility of congenital cardiac status to predict endoscopic third ventriculostomy and ventriculoperitoneal shunt failure in hydrocephalic infants.

The effect of congenital cardiac status on endoscopic third ventriculostomy (ETV) and ventriculoperitoneal shunt (VPS) failure in hydrocephalic infants is unknown. Because cardiac status in infants can impact central venous pressure (CVP), it is possible that congenital heart disease (CHD) and congenital cardiac anomalies may render these cerebrospinal fluid diversion interventions more susceptible to failure. Correspondingly, the aim of this study was to determine how CHD and congenital cardiac anomalies may impact the failure of these initial interventions. A retrospective review of the Nationwide Inpatient Sample (NIS) database was conducted. Infants (aged < 1 year) with known congenital cardiac status managed with either ETV or VPS were included. Quantitative data were compared using either parametric or nonparametric methods, and failure rates were modeled using univariable and multivariable regression analyses. A total of 18,763 infants treated with ETV or VPS for hydrocephalus were identified in our search, with ETV used to treat 7657 (41%) patients and VPS used to treat 11,106 (59%). There were 6722 (36%) patients who presented with CHD at admission, and a total of 25 unique congenital cardiac anomalies were detected across the cohort. Overall, the most common anomaly was patent ductus arteriosus (PDA) in 4990 (27%) patients, followed by atrial septal defect (ASD) in 2437 (13%) patients and pulmonary hypertension in 810 (4%) patients. With respect to initial intervention failure, 3869 (21%) patients required repeat surgical intervention during admission. This was significantly more common in the ETV group than the VPS group (36% vs 10%, p < 0.01). In both the ETV and VPS groups, CHD (p < 0.01), including all congenital cardiac anomalies, was an independent and significant predictor of failure. ASD (p < 0.01) and PDA (p < 0.01) both significantly predicted ETV failure, and PDA (p < 0.01) and pulmonary hypertension (p = 0.02) both significantly predicted VPS failure. These results indicate that congenital cardiac status predicts ETV and VPS failure in patients with infantile hydrocephalus. The authors hypothesized that this finding was primarily due to changes in CVP; however, this may not be completely universal across both interventions and all congenital cardiac anomalies. Future studies about optimization of congenital cardiac status with ETV and VPS are required to understand the practical significance of these findings.

Impact of Double-Machine Replacement Protocol at Start of Continuous Renal Replacement Therapy in Vasopressor-Dependent Patients: A Retrospective Cohort Study

Introduction: When starting continuous renal replacement therapy (CRRT), vasopressor-dependent patients are at risk of hemodynamic instability. Thus far, only a few studies have analyzed the impact of CRRT circuit replacement for vasopressor-dependent patients. Hence, we compared the effect of double-machine replacement protocol (DMRP) with single-machine replacement protocol (SMRP) for CRRT circuit replacement in vasopressor-dependent patients. Methods: The medical records of 96 vasopressor-dependent patients treated with CRRT in the general intensive care unit of the Shunde Hospital, Southern Medical University, between January 2017 and April 2018 were retrospectively analyzed. The major measures of the SMRP included returning the blood to the patient and sealing access catheter with heparin and starting a new CRRT machine with a slow blood pump, while DMRP involved simultaneous drawing and return of blood with two machines using a slow blood pump for circuit replacement. The primary outcome measures were changes in vasopressor dose and hemodynamic parameters, and the secondary outcome measure was the pause time difference between the two groups during the period. Results: A total of 53 patients were treated with SMRP and 43 patients with DMRP. Heart rate was higher in the SMRP group as compared to the DMRP group (p < 0.05). There were no significant changes in central venous pressure, mean arterial pressure, and vasopressor dose in either group (p > 0.05). The patients in the DMRP group had a significant reduction in CRRT pause time (5.62 ± 0.69 min in DMRP group vs. 37.01 ± 8.72 min in SMRP group, p < 0.01). The DMRP group needed a lower volume of circuit purging and priming fluid related to CRRT circuit replacement (0 mL in DMRP group vs. 463 mL in SMRP group). Conclusions: Implementation of the DMRP for CRRT circuit replacement had a slight hemodynamic effect on vasopressor-dependent patients. It also reduced the pause time and volume of circuit purging and priming fluid related to CRRT circuit replacement compared with SMRP.

Effects of continuous goal-directed analgesia on fluid resuscitation of massive burn patients during shock

Effects of continuous goal-directed analgesia on fluid resuscitation of massive burn patients during shock

Efficacy of Stroke Volume Variation-guided Fluid Management of Patients undergoing Off-pump Coronary Artery Bypass Grafting: An Observational Comparative Study between Open and Closed Chest

Introduction: Functional haemodynamic monitoring using dynamic parameter such as Stroke Volume Variation (SVV), based on pulse contour analysis, helps in predicting fluid responsiveness in off pump Coronary Artery Bypass Grafting (CABG) surgery. This allows adequate volume replacement to achieve optimal cardiac performance. Aim: To evaluate the efficacy of SVV in predicting volume responsiveness and effect on haemodynamic variable in patients undergoing off pump CABG in both closed and open chest. Materials and Methods: This single-centre, non randomised observational study was conducted at a tertiary medical college and hospital (LokmanyaTilak Municipal Medical College and General Hospital) Mumbai, Maharashtra, India, from December 2016 to December 2018. A total of 34 patients undergoing elective off pump CABG were included. Haemodynamic measurements Stroke Volume (SV), Cardiac Output (CO), Cardiac Index (CI), and SVV, were recorded with the transducer positioned at the level of midaxillary line. If the SVV was equal to or higher than 12, 100 mL fluid aliquot was given to patients. Endpoints for fluid aliquots was increase in CO by 15%, decrease in SVV of less than 12 or an increase Central Venous Pressure (CVP) upto 15 millimeter of mercury (mmHg). Number of times SVV above 12 during the procedure was recorded. SVV was considered as fluid responsive “if there was an increase in SV by 5%”. Statistical analysis was done using Student’s t-test (two tailed, dependent) on continuous parameters. The p-value &lt;0.05, was considered significant. Results: Out of 103 events of rise in SVV, 65 (63.1%) occurred when chest was open and 38 (36.9%) while chest was closed. The SVV-guided fluid response was 76.3% in closed chest and 75.4% in open chest and there was no significant difference. (p-value=0.91). There was a significant increase in SV (p-value&lt;0.01), CO (p-value=0.04), and significant decrease in SVV (p-value&lt;0.01) and heart rate (p-value&lt;0.01) after fluid loading in the responsive group when compared with non responsive group. There was no statistically significant difference between percentage change in SV, CO, CI, SBP, DBP, MAP and CVP between closed and open chest conditions after fluid replacement. Conclusion: SVV is not affected by open or closed chest conditions in mechanically ventilated patients undergoing CABG and can be used as a guide for fluid replacement. Weather open or closed chest conditions, few patients do not respond to fluid replacement when SVV are more than 12 by an increase in SV, cardiac output or CI, the cause of which remains to be determined.

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

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

Transient effects of carotid baroreflex stimulation via the neck chamber device on central venous pressure.

We examined in 11 young subjects (age 29.7±3.6 years, mean±SEM) whether carotid baroreceptor stimulation via the neck chamber device may affect central venous pressure (CVP), thus potentially involving other reflexogenic areas in the examined responses. Application of progressively greater neck chamber subatmospheric pressures caused a progressive lengthening in RR interval, which reached a peak at the maximal value of negative neck chamber pressure applied. This was accompanied by significant and progressively greater reduction in CVP values when the data were calculated considering the early changes occurring within the first 2 seconds of the stimulus. There was a weak correlation between the early changes in CVP and the RR interval responses when all stimuli were pooled together (r = 0.32, P < .05). The results of the present study suggest that the neck chamber technique employed to assess carotid baroreceptor‐heart rate sensitivity can transiently affect via the CVP reduction cardiopulmonary receptors activity, which may participate at the integrated reflex responses.

The use of point-of-care assessments and advanced hemodynamic monitoring in a patient with Eisenmenger syndrome for cesarean section: A case report.

IntroductionEisenmenger syndrome should be diagnosed before pregnancy and surgically corrected if possible. Cesarean section in a patient with Eisenmenger syndrome is high risk as morbidity and mortality are very high. Delivery in hospitals with intensive care units should be recommended. Use of point-of-care assessments and advanced monitors allow accurate management.Case presentationA primigravid with congestive heart failure from a patent ductus arteriosus in Eisenmenger syndrome, presented with threatened preterm labor and uncontrolled hypertension prompting cesarean delivery under epidural anesthesia. Pre-induction focused echocardiography revealed normal right ventricular function and severe pulmonary hypertension. Intraoperatively, hemodynamics became unstable. The decision to use fluids, vasopressor and inotrope was guided by analyses of arterial pulse contour, central venous pressure waveform and blood exams. Hemodynamics improved and a live baby was delivered. Postoperative course was unremarkable.DiscussionThe cause of hemodynamic instability must be accurately determined as inappropriate use of fluid or medication may be detrimental to a patient with Eisenmenger syndrome. In this case, advanced hemodynamic monitoring showed changes in central venous pressure, cardiac output and systemic vascular resistance which differentiated the causes of hypotension and desaturation. Point-of-care blood analysis showed acidosis and hypoxia which may have worsened the right-to-left shunt, contributing to the desaturation. Fluid and drug infusions to address identified problems were then guided by advanced monitors.ConclusionThe use of point-of-care assessments and advanced hemodynamic monitoring allowed accurate diagnoses and goal-directed therapies leading to improved patient safety and outcomes. The need for prolonged intensive care in this case was prevented.

Advanced respiratory monitoring in mechanically ventilated patients with coronavirus disease 2019-associated acute respiratory distress syndrome.

Purpose of reviewTo summarize the current knowledge about the application of advanced monitoring techniques in coronavirus disease 2019 (COVID-19).Recent findingsDue to the heterogeneity between patients, management of COVID-19 requires daily monitoring of and/or aeration and inspiratory effort. Electrical impedance tomography can be used to optimize positive end-expiratory pressure, monitor the response to changes in treatment or body position and assess pulmonary perfusion and ventilation/perfusion matching. Lung ultrasound is more readily available and can be used to measure and monitor recruitment, provide an indication of diaphragm function and pulmonary perfusion disturbances. Esophageal pressure measurements enable the calculation of the transpulmonary pressure and inspiratory effort in order to prevent excessive stress on the lung. While esophageal pressure measurements are the golden standard in determining inspiratory effort, alternatives like P0.1, negative pressure swing during a single airway occlusion and change in central venous pressure are more readily available and capable of diagnosing extreme inspiratory efforts.SummaryAlthough there is little data on the effectiveness of advanced monitoring techniques in COVID-19, regular monitoring should be a central part of the management of COVID-19-related acute respiratory distress syndrome (C-ARDS).

The effects of positive end-expiratory pressure on central venous pressure in patients with different chest wall elastic resistance

Objective: To investigate the role of chest wall elastic resistance in determining the effects of positive end-expiratory pressure (PEEP) on central venous pressure (CVP) in patients with mechanical ventilation (MV). Methods: In this prospective study, according to the median of ratio of chest wall elastic resistance to respiratory system elastic resistance (Ers), patients were divided into high chest wall elastic resistance group (Ecw/Ers≥0.24) and low chest wall elastic resistance group [elastance of chest wall (Ecw)/Ers<0.24]. PEEP was set at 5, 10, 15 cmH2O (1 cmH2O=0.098 kPa) respectively. Clinical data including CVP, heart rate (HR), blood pressure (BP) and respiratory mechanics were recorded. Results: Seventy patients receiving MV were included from November 2017 to December 2018. Clinical characteristics including age, BP, HR, baseline PEEP, the ratio of arterial oxygen partial pressure to fractional inspired oxygen (P/F) and comorbidities were comparable in two groups. However, patients with high Ecw/Ers ratio presented higher body mass index (BMI) than those with low Ecw/Ers ratio[ (25.4±3.2) kg/m2 vs. (23.4±3.2) kg/m2, P=0.011]. As PEEP increased from 5 cmH2O to 10 cmH2O, CVP in high Ecw/Ers group increased significantly compared with that in low Ecw/Ers group [1.75(1.00, 2.13) mmHg (1 mmHg=0.133kPa) vs. 1.50(0.50, 2.00)mmHg,P=0.038], which was the same as PEEP increased from 10 cmH2O to 15 cmH2O [2.00(1.50, 3.00)mmHg vs. 1.50(1.00, 2.00)mmHg,P=0.041] or PEEP increased from 5 cmH2O to 15 cmH2O [ 3.75(3.00,4.63)mmHg vs. 3.00(1.63, 4.00)mmHg, P=0.012]. When PEEP increased from 5 cmH2O to 10 cmH2O, 10 cmH2O to 15 cmH2O and 10 cmH2O to 15 cmH2O, there were significant correlations between Ecw/Ers and CVP elevation (r=0.29, P=0.016; r=0.31, P=0.011; r=0.31, P=0.01 respectively). Conclusions: In patients receiving mechanical ventilation, elevation of PEEP leads to a synchronous change of CVP, which is corelated with patients' chest wall elastic resistances.