A comparison of ClearSight noninvasive cardiac output and pulmonary artery bolus thermodilution cardiac output in cardiac surgery patients

Fluid responsiveness and hypotension in patients undergoing propofol-based sedation for colonoscopy following bowel preparation: a prospective cohort study

PURPOSE

Fasting and bowel preparation may deplete intravascular volume in patients undergoing colonoscopy. Nevertheless, rigorous demonstration of volume depletion and assessment of clinical consequences is lacking. We designed this study to explore the relationship between intravascular volume status and intraprocedural hypotension and to compare transthoracic echocardiography (TTE) and the ClearSight™ (Edwards Lifesciences, Irvine, CA, USA) noninvasive cardiac output monitor to measure intravascular volume status.

METHODS

We recruited adult patients undergoing elective colonoscopy following bowel preparation at the Royal Melbourne Hospital. We assessed the volume status preprocedure by taking TTE and ClearSight measurements in patients in the semirecumbent position and following passive leg raising. Patients received propofol-based sedation, and significant intraprocedural hypotension was defined as a mean arterial pressure (MAP) < 60 mm Hg. The primary outcome was the occurrence of intravascular volume depletion as assessed by a positive result in a passive leg raise test on TTE (a 15% increase in the subaortic velocity time integral).

RESULTS

Ninety-nine patients completed the study. The primary outcome was recorded in 29 of the 90 patients with adequate TTE images (32%; 95% confidence interval, 23 to 43). There was inadequate agreement between average TTE and ClearSight measurements of stroke volume at baseline or after passive leg raising. More patients experienced significant intraprocedural hypotension in the fluid-responsive group (48%) than in the normovolemic group (21%).

CONCLUSION

Patients undergoing elective colonoscopy after bowel preparation were often fluid responsive. These patients were more likely to have significant intraprocedural hypotension than patients who were volume replete. Transthoracic echocardiography assessment of volume status cannot be readily replaced by ClearSight monitoring.

STUDY REGISTRATION

ANZCTR.org.au ( ACTRN12616000614493 ); first registered 11 May 2016.

Continuous Non-Invasive Hemodynamic Monitoring in Cirrhotic Patients-Friend or Foe?

Background and Objectives: Liver cirrhosis leads to significant hemodynamic changes, particularly portal hypertension and a hyperdynamic circulatory state. Traditional invasive methods for hemodynamic monitoring, while accurate, carry risks such as infection and hemorrhage in a patient predisposed to these conditions. This study evaluates the accuracy of non-invasive continuous hemodynamic monitoring compared to a minimally invasive method in patients with decompensated liver cirrhosis. Materials and Materials and Methods: The study enrolled 51 patients with decompensated liver cirrhosis requiring continuous hemodynamic monitoring in the ICU. Patients underwent simultaneous monitoring via the minimally invasive FloTrac system and continuous non-invasive ClearSight sensor over 24 h, with measurements registered at 6 h intervals. Hemodynamic parameters measured included cardiac output (CO), cardiac index (CI), stroke volume (SV), stroke volume variation (SVV), systemic vascular resistance (SVR), and mean arterial pressure (MAP). Results: Significant discrepancies were observed between the two monitoring methods for most parameters, particularly CO, CI, and MAP, at most time intervals. However, SVV measurements showed no significant differences, indicating similar efficacy in assessing fluid responsiveness between the devices. Conclusions: The ClearSight system, although a valuable non-invasive alternative, demonstrated lower accuracy compared to the FloTrac system for hemodynamic measurements in patients with decompensated liver cirrhosis. Its effectiveness in assessing fluid responsiveness, particularly by SVV, suggests it could play a role in the monitoring of these patients, especially when invasive techniques have increased risks.

Continuous non-invasive vs. invasive arterial blood pressure monitoring during neuroradiological procedure: a comparative, prospective, monocentric, observational study

BACKGROUND

In the perioperative setting, the most accurate way to continuously measure arterial blood pressure (ABP) is using an arterial catheter. Surrogate methods such as finger cuff have been developed to allow non-invasive measurements and are increasingly used, but need further evaluation. The aim of this study is to evaluate the accuracy and clinical concordance between two devices for the measurement of ABP during neuroradiological procedure.

METHODS

This is a prospective, monocentric, observational study. All consecutive patients undergoing a neuroradiological procedure were eligible. Patients who needed arterial catheter for blood pressure measurement were included. During neuroradiological procedure, ABP (systolic, mean and diatolic blood pressure) was measured with two different technologies: radial artery catheter and Nexfin. Bland-Altman and error grid analyses were performed to evaluate the accuracy and clinical concordance between devices.

RESULTS

From March 2022 to November 2022, we included 50 patients, mostly ASA 3 (60%) and required a cerebral embolization (94%) under general anaesthesia (96%). Error grid analysis showed that 99% of non-invasive ABP measures obtained with the Nexfin were located in the risk zone A or B. However, 65.7% of hypertension events and 41% of hypotensive events were respectively not detected by Nexfin. Compared to the artery catheter, a significant relationship was found for SAP (r2 = 0.78) and MAP (r2 = 0.80) with the Nexfin (p < 0.001). Bias and limits of agreement (LOA) were respectively 9.6 mmHg (- 15.6 to 34.8 mmHg) and - 0.8 mmHg (- 17.2 to 15.6 mmHg), for SAP and MAP.

CONCLUSIONS

Nexfin is not strictly interchangeable with artery catheter for ABP measuring. Further studies are needed to define its clinical use during neuroradiological procedure.

TRIAL REGISTRATION

Clinicaltrials.gov, registration number: NCT05283824.

Feasibility of continuous non-invasive delivery of oxygen monitoring in cardiac surgical patients: a proof-of-concept preliminary study

PURPOSE

Oxygen delivery (DO2) and its monitoring are highlighted to aid postoperative goal directed therapy (GDT) to improve perioperative outcomes such as acute kidney injury (AKI) after high-risk cardiac surgeries associated with multiple morbidities and mortality. However, DO2 monitoring is neither routine nor done postoperatively, and current methods are invasive and only produce intermittent DO2 trends. Hence, we proposed a novel algorithm that simultaneously integrates cardiac output (CO), hemoglobin (Hb) and oxygen saturation (SpO2) from the Edwards Life Sciences ClearSight System® and Masimo SET Pulse CO-Oximetry® to produce a continuous, real-time DO2 trend.

METHODS

Our algorithm was built systematically with 4 components - machine interface to draw data with PuTTY, data extraction with parsing, data synchronization, and real-time DO2 presentation using a graphic-user interface. Hb readings were validated.

RESULTS

Our algorithm was implemented successfully in 93% (n = 57 out of 61) of our recruited cardiac surgical patients. DO2 trends and AKI were studied.

CONCLUSION

We demonstrated a novel proof-of-concept and feasibility of continuous, real-time, non-invasive DO2 monitoring, with each patient serving as their own control. Our study also lays the foundation for future investigations aimed at identifying personalized critical DO2 thresholds and optimizing DO2 as an integral part of GDT to enhance outcomes in perioperative cardiac surgery.

Can Currently Available Non-invasive Continuous Blood Pressure Monitors Replace Invasive Measurement With an Arterial Catheter?

Deviations from normal blood pressure (BP) during general anesthesia have been clearly linked to several adverse outcomes. Measuring BP accurately is therefore critically important for producing excellent outcomes in health care. Normal BP does not necessarily guarantee adequate organ perfusion however and adverse events have occurred even when BP seemed adequate. Invasive blood pressure monitoring has recently evolved beyond merely measuring BP. Arterial line-derived pulse contour analysis is used now to assess both cardiac output and stroke volume variation as indices of adequate intravascular volume. Confirmation of acceptable cardiac output with data derived from invasive intra-arterial catheters has become very important when managing high-risk patients. Newer devices that measure BP continuously and non-invasively in the digital arteries via a finger cuff have also become available. Many clinicians contemplate now if these new devices are ready to replace invasive monitoring with an arterial catheter. Unlike non-invasive devices, intra-arterial catheters allow frequent blood sampling. This makes it possible to assess vital parameters like pH, hemoglobin concentration, ionized calcium, potassium, glucose, and arterial partial pressure of oxygen and carbon dioxide frequently. Non-invasive continuous BP measurement has been found to be unreliable in critically ill patients, the elderly, and patients with calcified arteries. Pulse contour-derived estimates of cardiac output and stroke volume variation have been validated better with data derived from arterial lines than that from the newer finger cuff monitors. Significant advances have been recently made with non-invasive continuous BP monitors. Invasive monitoring with an arterial line however remains the gold standard for measuring BP and assessing pulse contour analysis-derived hemodynamic variables in critically ill patients. In the future, non-invasive continuous BP monitors will likely replace intermittent oscillometers in the operating room and the postoperative period. They will however not eliminate the need for arterial catheterization in critically ill patients.

Patent landscape review of non-invasive medical sensors for continuous monitoring of blood pressure and their validation in critical care practice

Objectives

Continuous non-invasive monitoring of blood pressure is one of the main factors in ensuring the safety of the patient's condition in anesthesiology, intensive care, surgery, and other areas of medicine. The purpose of this work was to analyze the current patent situation and identify directions and trends in the application of non-invasive medical sensors for continuous blood pressure monitoring, with a focus on clinical experience in critical care and validation thereof.

Materials and methods

The research results reflect data collected up to September 30, 2022. Patent databases, Google Scholar, the Lens database, Pubmed, Scopus databases were used to search for patent and clinical information.

Results

An analysis of the patent landscape indicates a significant increase in interest in the development of non-invasive devices for continuous blood pressure monitoring and their implementation in medical practice, especially in the last 10 years. The key players in the intellectual property market are the following companies: Cnsystems Medizintechnik; Sotera Wireless INC; Tensys Medical INC; Healthstats Int Pte LTD; Edwards Lifesciences Corp, among others. Systematization of data from validation and clinical studies in critical care practice on patients with various pathological conditions and ages, including children and newborns, revealed that a number of non-invasive medical sensor technologies are quite accurate and comparable to the "gold standard" continuous invasive blood pressure monitoring. They are approved by the FDA for medical applications and certified according to ISO 81060-2, ISO 81060-3, and ISO/TS 81060-5. Unregistered and uncertified medical sensors require further clinical trials.

Conclusion

Non-invasive medical sensors for continuous blood pressure monitoring do not replace, but complement, existing methods of regular blood pressure measurement, and it is expected to see more of these technologies broadly implemented in the practice in the near future.