Central Venous Pressure Measurement Research Articles

Correlation analysis of central venous pressure and Intra-thoracic pressures in Acute Respiratory Distress Syndrome mechanical ventilated patients, a pilot Study

Abstract Background Positive end expiratory pressure can affect measurement of central venous pressure through increased intrathoracic pressure. However, when positive end expiratory pressure (PEEP) is applied, central venous pressure and pleural pressure often increases more than right atrial pressure, so that transmural right atrial pressure (true filling pressure) decreases. Aim of the study Primary end point was to recognizing correlation coefficient between mean CVP and intra- thoracic pressures on volume-controlled mode and spontaneous modes on same population of mechanically ventilated ARDS patients. The secondary end point is to compare the correlation coefficient R during both modes with parameters of ventilatory settings. Patient and Methods A cohort observational prospective study was done enrolling single group of patients with acute respiratory distress syndrome, who necessitate mechanical ventilation more than two days after connection to ventilators, the study was performed with demonstration of central venous pressure in cmH2O upon application of needed PEEP. Central venous catheter inserted for measuring CVP were processed in accordance with the standard guidelines. Results There were statistically significant differences between control and support group regarding the PEEP, Plateau pressure, mean CVP and mean airway pressure MAP. The data were higher in control than support group with p-value <0.001, 0.002 and 0.004, respectively. There was statistically significant positive correlation between R and CVP in the control group with p < 0.001 and r = 0.918. There was statistically significant positive correlation between R and ΔPIT in support group with p 0.001 and r = 0.926. The correlation between CVP and R among the control group was R = 0.028 + 0.032 * CVP with p-value <0.001, whereas the correlation between ΔPIT and R among the support group was R = 0.465 + 0.020 * ΔPIT with p-value = 0.022 Conclusion The relation between hemodynamics change of central venous pressures and intrathoracic pressure is new independent marker for evaluating ARDS mechanically ventilated patients. Values of R correlation are different in controlled mode relative to spontaneous mode during ARDS ventilated patients.

Correlation between Central Venous Pressure and Inferior Vena Cava Diameter for Fluid Assessment in Patients with Chronic Obstructive Pulmonary Disease

Abstract Background Chronic obstructive pulmonary disease (COPD) is now the third leading cause of death globally.3 Although COPD primarily affects the lungs, it is now also recognized as a complex multi-component disease characterized by chronic systemic inflammation that frequently coexists with other conditions known as co morbidities. Objective To determine the correlation between central venous pressure (CVP) and the IVC collapsibility index for estimating the fluid status in COPD patients. Patients and Methods After obtaining the approval of the Ain Shams University Ethical Committee and written informed consent, 20 patients aged 21 - 60 years of either sex, admitted in the ICU of Ain Shams teaching hospitals who have a functioning central venous catheter inserted for any clinical indication, were involved in this correlational study. CVP measurements were taken with the patient in the supine position from the zero point and the middle line. Results The current study showed that there was no statically significant correlation Between CVP (cmH2O) and Heart Rate (beat /min), MABP (mmHg), IVCd max (cm) and IVC CI % at Baseline, After PLR test, After Bolus fluid administration, After 3 hours and After 6 hours. Conclusion The measurement of the IVC diameter has a good correlation with CVP and useful for assessment of the volume status. The measurement of the IVC by ultrasonography may be an important additional evaluation of critically ill patients.

Ultrasound based estimate of central venous pressure: Are we any closer?

Central venous pressure (CVP) serves as a direct approximation of right atrial pressure and is influenced by factors like total blood volume, venous compliance, cardiac output, and orthostasis. Normal CVP falls within 8-12 mmHg but varies with volume status and venous compliance. Monitoring and managing disturbances in CVP are vital in patients with circulatory shock or fluid disturbances. Elevated CVP can lead to fluid accumulation in the interstitial space, impairing venous return and reducing cardiac preload. While pulmonary artery catheterization and central venous catheter obtained measurements are considered to be more accurate, they carry risk of complications and their usage has not shown clinical improvement. Ultrasound-based assessment of the internal jugular vein (IJV) offers real-time, non-invasive measurement of static and dynamic parameters for estimating CVP. IJV parameters, including diameter and ratio, has demonstrated good correlation with CVP. Despite significant advancements in non-invasive CVP measurement, a reliable tool is yet to be found. Present methods can offer reasonable guidance in assessing CVP, provided their limitations are acknowledged.

Association between early central venous pressure measurement and all-cause mortality in critically ill patients with heart failure: A cohort of 11,241 patients

BackgroundThe timing of central venous pressure (CVP) measurement may play a crucial role in heart failure management, yet no studies have explored this aspect. MethodsClinical information pertaining to patients in critical condition with a diagnosis of heart failure was retrieved from the MIMIC-IV database. The association between initial measurements of central venous pressure (CVP) and the incidence of mortality from all causes was analyzed using the Cox proportional hazards approach. Subgroup analysis and propensity score matching were conducted for sensitivity analyses. ResultsThis study included 11,241 participants (median age, 75 years; 44.70 % female). Utilizing restricted cubic spline and Kaplan–Meier survival analyses, it was determined that prognostic outcomes were better when CVP was measured within the initial 5-h window. Multivariate-adjusted 1-year (HR: 0.69; 95 % CI: 0.61–0.77), 90-day (HR: 0.70; 95 % CI: 0.62–0.80), and 30-day (HR: 0.67; 95 % CI: 0.57–0.78) all-cause mortalities were significantly lower in patients with early CVP measurement, which was proved robustly in subgroup analysis. Subsequent to the application of propensity score matching, a cohort of 1536 matched pairs was established, with the observed mortality rates continuing to be significantly lower among participants who underwent early CVP assessment. ConclusionsEarly CVP measurement (within 5 h) demonstrated an independent correlation with a decrease in both immediate and extended all-cause mortality rates among patients in critical condition suffering from heart failure.

Correlation of Internal Jugular Vein and Inferior Vena Cava Collapsibility Index with Direct Central Venous Pressure Measurement in Critically-ill Patients: An Observational Study

Correlation of Internal Jugular Vein and Inferior Vena Cava Collapsibility Index with Direct Central Venous Pressure Measurement in Critically-ill Patients: An Observational Study

Venous Congestion Assessed by Venous Excess Ultrasound (VExUS) and Acute Kidney Injury in Children with Right Ventricular Dysfunction.

Right ventricular dysfunction (RVD) is a complication following congenital cardiac surgery in children and can lead to systemic venous congestion, low cardiac output, and organ dysfunction. Venous congestion can be transmitted backwards and adversely affect encapsulated organs such as the kidneys. To investigate the association between systemic venous congestion, as estimated by Venous Excess Ultrasound (VExUS), and the occurrence of acute kidney injury (AKI) in children with RVD following congenital heart surgery. Secondary objectives included comparing changes in VExUS scores after initiating treatment for RVD and venous congestion. This was a prospective observational study in children with RVD. The VExUS study was performed on day 1, day 2, and day 3 and categorized as VExUS-1, VExUS-2, and VExUS-3. Among 43 patients with RVD and dilated inferior vena cava, 19/43 (44%), 10/43 (23%), and 12/43 (28%) were VExUS-2 and VExUS-3, respectively. There was an association between severe RVD and elevated pulmonary artery systolic pressures and a VExUS score >2. A significant association was observed between central venous pressure (CVP) measurements and VExUS. Among 31 patients with a high VExUS score >2, 18 (58%) had AKI. Additionally, improvement in CVP and fluid balance was associated with improving VExUS scores following targeted treatment for RVD. VExUS serves as a valuable bedside tool for diagnosing and grading venous congestion through ultrasound Doppler. An elevated VExUS score was associated with the occurrence of AKI, and among the components of VExUS, portal vein pulsatility may be useful as a predictor of AKI. Natraj R, Bhaskaran AK, Rola P, Haycock K, Siuba MTT, Ranjit S. Venous Congestion Assessed by Venous Excess Ultrasound (VExUS) and Acute Kidney Injury in Children with Right Ventricular Dysfunction. Indian J Crit Care Med 2024;28(5):447-452.

Correlation between echocardiographic estimation of right atrial pressure and invasive measurement of central venous pressure in postoperative pediatric patients with congenital heart disease: a prospective observational study

BackgroundRight atrial pressure plays a critical role as a hemodynamic parameter in diagnosing pulmonary hypertension and other cardiac diseases, as well as guiding the treatment and prognosis of various cardiac disorders. If there is no obstruction between the inferior or superior vena cava (SVC) as central veins and the right atrium, the pressures in these veins could be considered equal to the right atrial pressure. This study aimed to examine the correlation between echocardiographic methods for estimating right atrial pressure and invasive measurements of central venous pressure (CVPi) in infants and children with congenital heart disease during the 48 h after cardiac surgery and to establish regression equations for echocardiographic estimation of central venous pressure (CVPe).ResultsWe prospectively enrolled 43 infants and children, ranging in age from 6 months to 16 years, including 20 males and 23 females. We found a significant correlation between CVPi and the ratio of the maximal diameter of IVC to the maximal diameter of the descending aorta ratio (IVCmax/DAOmax) (r = 0.529, P < 0.001), SVCS/D velocity ratio (SVCS/D) (r = 0.462, P = 0.006), right atrial vertical diameter (RAVD) (r = 0.409, P = 0.01), area (r = 0.384, P = 0.014), and tricuspid valve A wave acceleration rate (TVAAR) (r = 0.315, P = 0.048). Multiple regression analysis yielded an equation for estimating central venous pressure using four parameters related to the IVC, SVC, tricuspid valve, and right atrium. The equation is as follows: estimated CVP = 4.36 + (2.35 × IVCmax/DAOmax) + (1.06 × SVCS/D) + (0.059 × RAVD) + (0.001 × TVAAR). This equation is strongly correlated with CVPi (Pearson r = 0.698, P = 0.002).ConclusionsThe estimation of central venous pressure through a multi-parametric equation that included the ratio of the maximal diameter of the inferior vena cava to the maximal diameter of the descending aorta, the ratio of S to D velocity of the superior vena cava, the vertical diameter of the right atrium, and the acceleration rate of the A wave of the tricuspid valve demonstrated a robust correlation with invasively measured central venous pressure. To assess the accuracy of predicted pressures by this equation, further investigations are required to apply this innovative multi-parametric formula to a prospective population of pediatric patients with congenital heart disease.

The effect of different bed head angles on the hemodynamic parameters of intensive care patients lying in the supine position: A quasi-experimental study.

The aim of this study was to research the effect of different bed head angles on the hemodynamic parameters of intensive care patients lying in the supine position. This study was a non-randomized and non-controlled, quasi-experimental repeated measures study. The study was conducted with 50 intensive care patients aged 18 and over in a general surgery intensive care unit in Turkey. With each patient in the supine position, the bed head was raised to an angle of 0°, 20°, 30°, and 45° without a pillow, and the hemodynamic parameters of central venous pressure, systolic and diastolic blood pressure, heart rate, breathing rate, and peripheral oxygen saturation were recorded after 0 and 10 min. It was found that the mean central venous pressure value measured at min 0 and 10 was higher when the intensive care patients' bed head angle was raised to 45° than when the bed head was at an angle of 0° or 20° (p < .05). It was found that the patients' other hemodynamic parameters were not affected by different bed head angles. It was concluded as a result of this research that in intensive care patients in the supine position, only central venous pressure was affected by bed head angle, and that central venous pressure measurement can be reliably made at a bed head angle of 30°.

Assessment of renal congestion in a rat model with congestive heart failure using superb microvascular imaging.

Renal congestion is a therapeutic target in congestive heart failure. However, its detailed evaluation in a clinical setting is challenging. This study sought to assess renal congestion impairment using superb microvascular imaging (SMI), a simple and accessible method. Dahl salt-sensitive rats, used as a model for congestive heart failure, underwent central venous pressure (CVP) measurements. Renal congestion was evaluated through measurements of renal medullary pressure (RMP) and assessment of renal perfusion using contrast-enhanced ultrasonography at both the early (control group) and heart failure phases (HF group). All rats were assessed with SMI. The region of interest (ROI) was set in interlobular vessels, interlobar vessels, and a combination of these areas. The area ratio was calculated from the color pixel count in the ROI divided by the total pixel count in the ROI. Intrarenal perfusion index (IRPI) was defined as (maximum area ratio-minimum area ratio) / maximum area ratio. There were no significant differences in renal function and left ventricular ejection fraction between the two groups. CVP, time-to-peak (TTP) in the medulla, and RMP were higher in the HF group than in the control group. In the HF group, IRPI, evaluated in the interlobular vessels, was significantly higher than in the control group. IRPI was positively correlated with TTP in the medulla (p = 0.028, R = 0.60) and RMP (p < 0.001, R = 0.84), indicating that IRPI reflected renal congestion. IRPI is a useful tool for assessing renal congestion in rats with congestive heart failure.

Advantages of using ultrasound diagnostic methods in the practice of an anesthesiologist on the example of neurosurgical interventions in the sitting position in pediatric patients with brain tumors

The purpose of the publication is to improve the results of treatment of children with brain tumors with the help of high-quality monitoring during neurosurgical operations with the localization of pathological formations that require the patient to be in a sitting position; encourage anesthesiologists to acquire the necessary additional skills in ultrasound diagnostics.For the description of the clinical case, the authors obtained the written informed consent of patients No. 1 and No. 2 to use the materials of his medical history in the article, in accordance with the Ethical Standards of Legal Regulation of Relations.Two clinical cases of anesthesiological management of patients with neurooncopathology (neoplasm of the left cerebellar peduncle with prolapse in the IV ventricle area and volume formation of the pineal area) operated on in the sitting position with standard monitoring (pulse oximetry, electrocardiography, non-invasive measurement of arterial blood pressure, thermometry, capnography, other gas analyzer), supplemented by invasive measurement of central venous pressure, bispectral index (BIS) monitoring, neurophysiological parameters, transesophageal echocardiography (the sensor is selected according to the patient's age). Clinical, laboratory, biochemical, ultrasound, endoscopic, x-ray methods, computer and magnetic resonance imaging were used to establish a diagnosis, determine the nature of complications, choose access and methods of surgical intervention, evaluate the effectiveness of treatment and diagnostics.The sitting position during surgery is the neurosurgeon’s choice because this position improves access to the tumor, reduces the volume of blood loss and intracranial pressure, but increases the risk of intraoperative complications, in particular, air embolism, which was diagnosed by echocardiography. The National Children’s Specialized Hospital «Okhmatdyt» has the necessary equipment (in particular, a neurosurgical chair) for performing neurosurgical interventions in a sitting position. During the surgical intervention, in one clinical case, an air embolism of the 2nd degree according to the Tubingen scale was recorded, without other changes according to the measurement of arterial and central venous pressure, BIS and neurophysiological monitoring. In the second case, an air embolism of the 1st degree was recorded. Both patients were extubated on the operating table at the end of the operation and were observed during the day in the intensive care unit. The early postoperative period was uneventful. According to the control magnetic resonance imaging, postoperative moderate pneumocephalus developed, which did not require repeated surgical intervention. During the operation, monitoring was carried out using pulse oximetry and electrocardiography.This article does not aim to review the specific indications for transesophageal echocardiography or a comprehensive description of all complications that can be visualized using this method during operative neurosurgical interventions. This article presents two cases that demonstrate the success of using this method by an anesthesiologist. According to the authors, it is advisable to introduce the use of ultrasound methods into the daily practice of an anesthesiologist.High-quality monitoring is important for early detection and prevention of complications. Thanks to the professionalism and expanded arsenal of practical skills of the team of doctors of the NCSH «Okhmatdit», in particular, anesthesiologists, in both cases, high-tech medical care was provided with a good prognosis for the future life of these patients.

Evaluating the Impact of a Teaching Program on Nurses' Performance during CVP Measurement in Intensive Care Units: A Quasi-Experimental Study

The intensive care unit (ICU) is a specialized area of hospitals dealing with the diagnosis, management, and follow-up of critically ill patients. Moreover, Critical Care Nurses (CCNs) should have strong analytical, interpersonal, and decision-making skills. Objectives: This study aimed to assess the effect of the teaching program on CCNs’ performance during the measurement of central venous pressure (CVP). Design: A quasi-experimental design was used. Methods: The study was conducted in the critical care units at Al-Assad University Hospital, Damascus from June to September 2020. All available registered nurses working in the previous ICUs were included. An observational checklist sheet was developed by the researcher after reviewing the related literature. Each nurse was observed once for each procedure during different shifts. The researcher developed and designed the teaching program based on the nurses’ needs according to their performance during the initial assessment. Results: The results showed that the performance of the nurses improved after the program. The best performance was for nurses in the age group between 20 and 24 years, nurses with a master’s degree, and nurses with less than five years of experience, while the level of knowledge and practice of the studied nurses was average and poor before the teaching program. Overall, this study found a statistically significant relationship before and after the implementation of the program. Conclusion: There has been an obvious improvement in nurses’ knowledge and performance after the teaching program. It is essential to help nurses expand their knowledge and practices to provide high-quality care and promote patient safety.

Development of a Direct Non-Puncture Device for Measuring Portal Venous Pressure during Liver Transplantation-A Swine Model.

Portal hypertension-related complications pose a significant risk for liver failure post-transplantation. Thus, accurate monitoring of intraoperative portal venous pressure (PVP) is crucial. However, current PVP monitoring techniques requiring direct percutaneous puncture carry the risk of graft damage. In this study, we present an innovative non-puncture PVP monitoring device (PVPMD) using a 3D-printed prototype. PVPMD design is inspired by the sphygmomanometer principle, and strategically encompasses the portal vein and enables precise PVP measurement through blood flow ultrasonography after temporary occlusion. By a series of mini-pig experiments, the prototype PVPMD demonstrated a strong correlation with invasive catheter measurements in the main trunk of the portal vein (rs = 0.923, p = 0.000). There was a significant repeatability and reproducibility between the prototype PVPMD- and invasive catheter-measured PVP. This indicates that the PVPMD holds immense potential for direct application in liver transplantation and surgery. Moreover, it has the potential to replace catheter-based central venous pressure (CVP) measurements, thereby mitigating catheter-related complications during many surgeries. In conclusion, our innovative device represents a significant advancement in PVP monitoring during liver transplantation, with comprehensive validation from principle exploration to successful animal experiments. We anticipate that this groundbreaking PVPMD will attract the attention of researchers and clinicians, propelling the noninvasive measurement of PVP or other venous/arterial pressures into a new era of clinical practice.

Are dynamic measurements of central venous pressure in Fontan circulation during exercise or volume loading superior to resting measurements?

Abstract Background: The main objective measure to assess the health of the Fontan circulation is the pressure measurement of the superior vena cava or pulmonary arteries. We reviewed the literature for benefits of measuring resting pressure in the Fontan circuit and explored whether dynamic measurement by volume loading or exercise has the potential to refine this diagnostic tool. Methods: PubMed was searched for articles showing a relationship between resting post-operative central venous pressure or pulmonary artery pressure and Fontan failure. Relationships between post-operative central venous pressure or pulmonary artery pressure and volume loading changes, such as during exercise or volume loading during cardiac catheterization, were also queried. Results: A total of 44 articles mentioned relationships between resting central venous pressure or pulmonary artery pressure and Fontan failure. Only 26 included an analysis between the variables and only seven of those articles found pressure to be predictive of Fontan failure. Ten articles examined the relationship between exercise or volume loading and outcomes and demonstrated a large individual variation of pressures under these dynamic conditions. Conclusions: Based on current literature, there is not a lot of strong evidence to show that elevated resting central venous pressure or pulmonary artery pressure is predictive of Fontan failure. Some individuals experience dramatic increases in central venous pressure or pulmonary artery pressure under increased loading conditions with exercise or bolus fluid infusion, while others experience increases closer to that of a healthy control population. Further studies are needed to examine whether more dynamic and continuous monitoring of systemic venous pressures might better predict outcomes in patients with Fontan circulation.

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.

Invasive Monitoring in the Intensive Care Unit

The purpose of monitoring of the patient in an intensive care unit (ICU) is to improve patient care, like bringing about a change in the treatment or transfer of the patient to a step-down unit. Monitoring also shows the extent of compliance with a formulated standard of care or the degree of deviation from the expected standard of care. The monitoring used for a patient admitted to an ICU can be invasive or noninvasive. Invasive monitoring in an ICU includes arterial blood pressure, transesophageal Doppler, central venous pressure (CVP) measurement, pulmonary artery catheterization, arterial blood gas (ABG) analysis and measurement of intracranial pressure (ICP) and intra-abdominal pressure (IAP). Monitoring of the physiologic parameters depends on the underlying illness of the patient and the availability of equipment in the ICU.

Impact of central venous pressure measurement on the prognosis of patients with septic shock: A retrospective analysis of the MIMIC- IV database

Objective: To assess the impact of measuring central venous pressure (CVP) on the prognosis of patients with septic shock. Methods: Septic shock patients with and without CVP measurements were identified in the Medical Information Mart for Intensive Care IV database. The primary outcome was 28-day mortality, and a multivariate logistic regression model was used to analyze the association between CVP measurement and 28-day mortality in patients with septic shock. The results were validated using logistic regression after propensity score matching. Secondary outcomes were in-hospital mortality, 1-year mortality, incidence of acute kidney injury within the first 7 days in the intensive care unit (ICU), and length of stay in the ICU. After propensity score matching, logistic regression analysis was conducted to analyze the correlation between CVP measurements and secondary outcomes in patients with septic shock. Results: A total of 2966 patients were included, including 1219 patients whose CVP was measured within 24h after admission to the ICU. CVP measurement was found to be not correlated with 28-day mortality (odds ratio=0.978, 95% Confidence Interval 0.798-1.200, P=0.835). Analyzing the cohort after propensity score matching, CVP measurement was found to be associated with prolonged ICU stay (4.9 vs. 3.2 days; P&lt;0.001). No statistical differences were found in the primary outcome and other secondary outcomes between those with CVP measurement and those not. Conclusion: CVP measurement is associated with prolonged ICU stay in patients with septic shock but not associated with mortality and incidence of acute kidney injury within 7 days.

Development and Validation of the CVP Score: A Cross-Sectional Study in Greece.

Although central venous pressure (CVP) is among the most frequent estimated hemodynamic parameters in the critically ill setting, extremely little is known on how intensive care unit (ICU) nurses use this index in their decision-making process. The purpose of the study was to develop a new questionnaire for accessing how ICU nurses use CVP measurements to address patients' hemodynamics investigating its validity and reliability. A cross-sectional study was conducted among 120 ICU nurses from four ICUs of Greece. Based on a comprehensive literature review and the evaluation by a panel of five experts, a new questionnaire, named "CVP Score", was created, having eight items. The construct validity and the reliability of the questionnaire were examined. Half of the study participants (51.7%) worked at a specialized ICU, and they had a mean [±Standard Deviation (SD)] ICU experience of 13(±7.1) years. The estimated construct validity of the newly developed tool was acceptable, while the internal consistency reliability as measured by Cronbach alpha was excellent (0.901). CVP Score had acceptable test-retest reliability (r = 0.996, p < 0.001) and split-half reliability (0.855). The CVP score is a valid and reliable instrument for measuring how critical care nurses use CVP measurements in their decision-making process.

Lowest peak central venous pressure correlates with highest invasive arterial blood pressure as a method for optimising AV delay in post-surgical temporary pacing

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): British Heart Foundation. Background Atrioventricular (AV) delay optimisation has been performed using a variety of methods, including doppler outflow and alternating blood pressure algorithms. Patients after cardiac surgery are usually invasively monitored with arterial and central venous pressure (CVP) lines. Purpose We aimed to see if the CVP line could be used to optimise AV delays in temporary pacing for situations where the arterial line is absent or non-functional. Methods 11 patients in sinus rhythm but with temporary pacemakers after cardiac surgery were studied. Each patient underwent alternating optimisation algorithms where they were subjected to 8 transitions between a reference AV delay of 120ms and a tested AV delay ranging from 40ms to 280 ms. Testing was terminated after the AV delay occurred when native conduction occurred i.e after they began AAI pacing. All patients were paced at 80 bpm. Arterial blood pressure (ABP) and CVP were recorded from radial arterial lines and central venous lines in the internal jugular vein during the transitions. The optimal point was defined as the AV delay generating the maximum systolic blood pressure. The CVP was measured in 3 ways: peak pressure, mean pressure, and area under the curve. Central venous pressure tracings were corrected for respiration using a "fit-a-curve" function. All analysis was performed in Python. Results Individual pressure readings. There was a negative correlation between individual ABP and Peak CVP pressure readings (R= -0.539, p=0&amp;lt;0.001). A representative example for a single patient is shown in Figure 1 and for all data in Figure 2. A similar relationship, albeit less strong, was seen between ABP and Mean CVP (R= -0.281, p=0.046). There was no significant relationship between ABP and CVP AUC (R = -0.281, p=0.130). Optimum pressure settings: There was a strong correlation between the optimum AV delay as defined by the highest ABP and the optimum AVD as defined by the lowest peak CVP (R = 0.672, p=0.03). There was no significant relationship between the optimum AVD delay as defined by peak ABP and the optimum AVD defined by either mean CVP nor CVP AUC (R=0.269, p=0.452 for both). Conclusions There is an inverse relationship between individual measurements of arterial blood pressure and both peak and mean central venous pressure. The optimal AVD as defined by the highest ABP correlates with the optimal AVD as defined by the lowest peak CVP measurement. However, this method does require correction for respiratory artefact.

Impact of central venous pressure during the first 24 h and its time-course on the lactate levels and clinical outcomes of patients who underwent coronary artery bypass grafting.

Previous studies have revealed that elevated mean central venous pressure (CVP) was associated with poor prognosis in specific patient groups. But no study explored the impact of mean CVP on prognosis of patients who underwent coronary artery bypass grafting surgery (CABG). The purpose of this study was to investigate the impacts of elevated CVP and its time-course on clinical outcomes of patients who underwent CABG and potential mechanisms. A retrospective cohort study was performed based on the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. We first identified the CVP during specific period with the most predictive value. Patients were categorized into the low-CVP and high-CVP group on the basis of the cut-off value. A propensity score matching was used to adjust covariates. The primary outcome was a 28-day mortality. The secondary outcomes were 1-year mortality and in-hospital mortality, the length of intensive care unit (ICU) stay and hospitalization, acute kidney injury incidence, use of vasopressors, duration of ventilation and oxygen index, and lactate levels and clearance. Patients in the high-CVP group were categorized into the "second day CVP ≤ 13.46 mmHg" group and the "second day CVP > 13.46 mmHg" group, respectively, and the clinical outcomes were the same as before. A total of 6,255 patients who underwent CABG were picked from the MIMIC-IV database, of which 5,641 CABG patients were monitored by CVP measurement during the first 2 days after ICU admission and 206,016 CVP records were extracted from the database. The mean CVP during the first 24 h was the most correlative and statistically significant for the 28-day mortality. The risk of the 28-day mortality was increased in the high-CVP group [OR 3.45 (95% CI: 1.77-6.70; p < 0.001)]. Patients with elevated CVP levels had worse secondary outcomes. The maximum of lactate levels and lactate clearance were also poor in the high-CVP group. For patients in the high-CVP group during the first 24 h, whose mean CVP during the second day lowered to less than the cut-off value, had better clinical outcomes. An elevated mean CVP during the first 24 h was correlated with poor outcomes in patients who underwent CABG. The potential mechanisms may be influencing the lactate levels and lactate clearance through the impact on afterload of tissue perfusion. Patients whose mean CVP during the second day dropped to less than the cut-off value had favorable prognosis.

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

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. 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. 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. 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.