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

Effects of phenylephrine on systemic and cerebral circulations in humans: a systematic review with mechanistic explanations

We conducted a systematic review of the literature reporting phenylephrine-induced changes in blood pressure, cardiac output, cerebral blood flow and cerebral tissue oxygen saturation as measured by near-infrared spectroscopy in humans. We used the proportion change of the group mean values reported by the original studies in our analysis. Phenylephrine elevates blood pressure whilst concurrently inducing a reduction in cardiac output. Furthermore, despite increasing cerebral blood flow, it decreases cerebral tissue oxygen saturation. The extent of phenylephrine's influence on cardiac output (r = -0.54 and p = 0.09 in awake humans; r = -0.55 and p = 0.007 in anaesthetised humans), cerebral blood flow (r = 0.65 and p = 0.002 in awake humans; r = 0.80 and p = 0.003 in anaesthetised humans) and cerebral tissue oxygen saturation (r = -0.72 and p = 0.03 in awake humans; r = -0.24 and p = 0.48 in anaesthetised humans) appears closely linked to the magnitude of phenylephrine-induced blood pressure changes. When comparing the effects of phenylephrine in awake and anaesthetised humans, we found no evidence of a significant difference in cardiac output, cerebral blood flow or cerebral tissue oxygen saturation. There was also no evidence of a significant difference in effect on systemic and cerebral circulations whether phenylephrine was given by bolus or infusion. We explore the underlying mechanisms driving the phenylephrine-induced cardiac output reduction, cerebral blood flow increase and cerebral tissue oxygen saturation decrease. Individualised treatment approaches, close monitoring and consideration of potential risks and benefits remain vital to the safe and effective use of phenylephrine in acute care.

Comparison of direct intra-arterial pressure and ClearSight finger cuff arterial pressure measurements in elderly patients undergoing transcatheter aortic valve replacement

OBJECTIVE

This study aimed to assess the agreement between direct intra-arterial pressure and ClearSight finger cuff arterial pressure measurements in elderly patients undergoing transcatheter aortic valve replacement (TAVR).

METHODS

A prospective observational study was conducted at Hitachi General Hospital, Japan, involving 30 patients aged 65 years and older who underwent TAVR under general anesthesia. Intra-arterial pressure and finger cuff arterial pressure measurements were recorded for 30 min after valve deployment. Bland-Altman analysis, four-quadrant plot analysis, and error grid analysis were used to assess the concordance between the two methods. Multiple regression analysis was performed to explore potential confounding factors affecting the agreement.

RESULTS

The bias and precision of ClearSight measurements were -4.88 ± 15.46 (mmHg) for SBP, 4.73 ± 8.95 (mmHg) for mean, and 9.53 ± 9.01 (mmHg) for DBP. The Bland-Altman analysis demonstrated acceptable agreement between intra-arterial pressure and finger cuff arterial pressure measurements. The four-quadrant plot analysis showed good trend-tracking ability, and the error grid analysis revealed that most of the observed values fell into the no-risk category. The mean BP match ratio and SBP match ratio were influenced by several factors such as age, BSA, ejection fraction, valve size, and gender.

CONCLUSION

The ClearSight finger cuff arterial pressure measurement showed good agreement with direct intra-arterial pressure in elderly patients undergoing TAVR. However, factors such as age, BSA, ejection fraction, valve size, and gender may influence the agreement between the two methods.

Comparison of invasive and non-invasive measurements of cardiac index and systemic vascular resistance in living-donor liver transplantation: a prospective, observational study

BACKGROUND

Based on the controversy surrounding pulmonary artery catheterization (PAC) in surgical patients, we investigated the interchangeability of cardiac index (CI) and systemic vascular resistance (SVR) measurements between ClearSight™ and PAC during living-donor liver transplantation (LDLT).

METHODS

This prospective study included consecutively selected LDLT patients. ClearSight™-based CI and SVR measurements were compared with those from PAC at seven LDLT-stage time points. ClearSight™-based systolic (SAP), mean (MAP), and diastolic (DAP) arterial pressures were also compared with those from femoral arterial catheterization (FAC). For the comparison and analysis of ClearSight™ and the reference method, Bland-Altman analysis was used to analyze accuracy while polar and four-quadrant plots were used to analyze the trending ability.

RESULTS

From 27 patients, 189 pairs of ClearSight™ and reference values were analyzed. The CI and SVR performance errors (PEs) exhibited poor accuracy between the two methods (51.52 and 51.73%, respectively) in the Bland-Altman analysis. CI and SVR also exhibited unacceptable trending abilities in both the polar and four-quadrant plot analyses. SAP, MAP, and DAP PEs between the two methods displayed favorable accuracy (24.28, 21.18, and 26.26%, respectively). SAP and MAP exhibited acceptable trending ability in the four-quadrant plot between the two methods, but not in the polar plot analyses.

CONCLUSIONS

During LDLT, CI and SVR demonstrated poor interchangeability, while SAP and MAP exhibited acceptable interchangeability between ClearSight™ and FAC.

Feasibility and Accuracy of Noninvasive Continuous Arterial Pressure Monitoring during Transcatheter Atrial Fibrillation Ablation

Introduction: Transcatheter atrial fibrillation (AF) ablation is still carried out with continuous invasive radial arterial blood pressure (IBP) monitoring in many centers. Continuous noninvasive blood pressure (CNBP) measurement using the volume-clamp method is a noninvasive alternative method used in ICU. No data on CNBP reliability are available in the electrophysiology lab during AF ablation, where rhythm variations are common. Background: The objective of the present study was to compare continuous noninvasive arterial pressure measured with the ClearSight device (Edwards Lifesciences, Irvine, CA, USA) with invasive radial artery pressure used as the reference method during AF ablation. Methods: We prospectively enrolled 55 consecutive patients (age 62 ± 11 years, 80% male) undergoing transcatheter AF ablation (62% paroxysmal, 38% persistent) at our center. Standard of care IBP monitoring via a radial cannula and a contralateral noninvasive finger volume-clamp CNBP measurement device were positioned simultaneously in all patients for the entire procedure. Bland-Altman analysis was used to analyze the agreement between the two techniques. Results: A total of 1219 paired measurements for systolic, diastolic, and mean arterial pressure were obtained in 55 subjects, with a mean (SD) of 22 (9) measurements per patient. The mean bias (SD) was −12.97 (13.89) mmHg for systolic pressure (level of agreement −14.24–40.20; correlation coefficient 0.84), −1.85 (8.52) mmHg for diastolic pressure (level of agreement −18.54–14.84; correlation coefficient 0.77) and 2.31 (8.75) mmHg for mean pressure (level of agreement −14.84–19.46; correlation coefficient 0.85). Conclusion: In patients undergoing AF ablation, CNBP monitoring with the ClearSight device showed acceptable agreement with IBP monitoring. Larger studies are needed to confirm the potential clinical implications of continuous noninvasive BP monitoring during AF ablation.

Non-invasive continuous blood pressure monitoring using the ClearSight system for pregnant women at high risks of post-partum hemorrhage: comparison with invasive blood pressure monitoring during cesarean section

Objective

This study aimed to investigate the accuracy and precision of continuous, non-invasive blood pressure obtained using the ClearSight system by comparing it with invasive arterial blood pressure, and to assess the hemodynamic changes using the ClearSight system in patients undergoing cesarean section.

Methods

Arterial pressure was measured invasively with an intra-arterial catheter and non-invasively using the ClearSight system during cesarean section in patients with placenta previa or placenta accreta. Blood pressure measurements obtained using these two means were then compared.

Results

Total 1,277 blood pressure measurement pairs were collected from 21 patients. Under Bland-Altman analysis, the ClearSight system demonstrated an acceptable accuracy with a bias and standard deviation of 8.8±13.4 mmHg for systolic blood pressure, -6.3±7.1 mmHg for diastolic blood pressure, and -2.7±8.0 mmHg for median blood pressure. Cardiac index levels were significantly elevated during fetal delivery and 5 minutes after placental removal, and systemic vascular resistance index levels were significantly decreased during fetal delivery and 40 minutes after placental removal.

Conclusion

In patients undergoing cesarean section, the ClearSight system showed excellent accuracy and precision compared to that of the currently used invasive monitoring system.

Diagnosis and Management of Patients With Myocardial Injury After Noncardiac Surgery: A Scientific Statement From the American Heart Association

Myocardial injury after noncardiac surgery is defined by elevated postoperative cardiac troponin concentrations that exceed the 99th percentile of the upper reference limit of the assay and are attributable to a presumed ischemic mechanism, with or without concomitant symptoms or signs. Myocardial injury after noncardiac surgery occurs in ≈20% of patients who have major inpatient surgery, and most are asymptomatic. Myocardial injury after noncardiac surgery is independently and strongly associated with both short-term and long-term mortality, even in the absence of clinical symptoms, electrocardiographic changes, or imaging evidence of myocardial ischemia consistent with myocardial infarction. Consequently, surveillance of myocardial injury after noncardiac surgery is warranted in patients at high risk for perioperative cardiovascular complications. This scientific statement provides diagnostic criteria and reviews the epidemiology, pathophysiology, and prognosis of myocardial injury after noncardiac surgery. This scientific statement also presents surveillance strategies and treatment approaches.

Noninvasive cardiac output measurement is inaccurate in patients with severe aortic valve stenosis undergoing transcatheter aortic valve implantation

Background

Noninvasive cardiac output (CO) measured using ClearSight™ eliminates the need for intra-arterial catheter insertion. The purpose of this study was to examine the accuracy of non-invasive CO measurement in patients with severe aortic stenosis (AS).

Methods

Twenty-eight patients undergoing elective transcatheter aortic valve implantation were prospectively enrolled in this study. The CO was simultaneously measured twice before and twice after valve deployment (total of four times) per patient, and the CO was compared between the ClearSight (CO_ClearSight) system and the pulmonary artery catheter (PAC) thermodilution (CO_TD) method as a reference. The Bland-Altman analysis was used to compare the percentage errors between the methods.

Results

A total of 112 paired data points were obtained. The percentage error between the CO_ClearSight and CO_TD was 43.1%. The paired datasets were divided into the following groups according to the systemic vascular resistance index (SVRI): low (< 1,200 dyne s/cm⁵/m²) and normal (1,200–2,500 dyne s/cm⁵/m²). The percentage errors were 44.9% and 49.4%, respectively. The discrepancy of CO between CO_ClearSight and CO_TD was not significantly correlated with SVRI (r = −0.06, P < 0.001). The polar plot analysis showed the trending ability of the CO_ClearSight after artificial valve deployment was 51.1% which below the acceptable cut-off (92%).

Conclusions

The accuracy and the trending ability of the ClearSight CO measurements were not acceptable in patients with severe AS. Therefore, the ClearSight system is not interchangeable with the PAC thermodilution for determining CO in this population.

Accuracy of noninvasive continuous arterial pressure monitoring using ClearSight during one-lung ventilation

Noninvasive continuous arterial pressure monitoring may be clinically useful in patients who require continuous blood pressure monitoring in situations where arterial catheter placement is limited. Many previous studies on the accuracy of the noninvasive continuous blood pressure monitoring method reported various results. However, there is no research on the effectiveness of noninvasive arterial pressure monitoring during one-lung ventilation. The purpose of this study was to compare arterial blood pressure obtained through invasive method and noninvasive method by using ClearSight during one-lung ventilation.In this retrospective observational study, a total of 26 patients undergoing one-lung ventilation for thoracic surgery at a single institution between March and July 2019 were recruited. All patients in this study were cannulated on their radial artery to measure continuously invasive blood pressures and applied ClearSight on the ipsilateral side of the cannulated arm. We compared and analyzed the agreement and trendability of blood pressure recorded with invasive and noninvasive methods during one-lung ventilation.Blood pressure and pulse rate showed a narrower limit of agreement with a percentage error value of around 30%. In addition, the tracking ability of each measurement could be determined by the concordance rate, all of which were below acceptable limits (92%).In noninvasive arterial blood pressure monitoring using ClearSight, mean blood pressure and pulse rate show acceptable agreement with the invasive method.

Continuous Non-Invasive Arterial Pressure Monitoring (ClearSight System) and Ankle Blood Pressure Measurements as Alternatives to Conventional Arm Blood Pressure

Measuring blood pressure (BP) via a pneumatic cuff placed around the arm has long been the standard method. However, in clinical situations where BP monitoring at the arm is difficult, the ankle is frequently used instead. We compared continuous non-invasive blood pressure (CNBP) measurements obtained at the finger, ankle BP and arm BP in patients undergoing breast cancer surgery. Arm BP, ankle BP (both obtained with a conventional pneumatic cuff) and CNBP measurements were obtained every 2.5 min during surgery. Correlation and Bland–Altman analyses were performed and differences among measurements were analyzed using a linear mixed model. A total of 245 sets of BP measurements were obtained from 10 patients. All systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean blood pressure (MBP) measurements of ankle BP and CNBP were positively correlated with the arm BP measurements (Spearman rho 0.688–0.836, p < 0.001 for each correlation). The difference between CNBP and arm SBP was significantly smaller (least squares mean (95% confidence interval): −6.03 (−11.40, −0.67)) compared to that between ankle and arm SBP (least squares mean (95% CI): −15.32 (−20.69, −9.96), p = 0.019). However, this significant difference was not observed in DBP and MBP (−1.23 vs. 1.75, p = 0.190 and −3.85 vs. −2.63, p = 0.604, respectively). Ankle SBP measurements showed larger differences from arm SBP measurements than did CNBP SBP measurements in patients undergoing breast cancer surgery. CNBP could serve as a useful alternative to ankle BP when standard arm BP measurements cannot be obtained.

Accuracy and Trending Ability of Cardiac Index Measured by the CNAP System in Patients Undergoing Abdominal Aortic Aneurysm Surgery

OBJECTIVES

The CNAP system is a noninvasive monitor that provides a continuous arterial pressure waveform using an inflatable finger cuff. The authors hypothesized that dramatic changes in systemic vascular resistance index during abdominal aortic aneurysm (AAA) surgery might affect the accuracy of noninvasive pulse contour monitors. The aim of this study was to evaluate the accuracy and trending ability of cardiac index derived by the CNAP system (CI_CN) in patients undergoing AAA surgery.

DESIGN

Prospective clinical study.

SETTING

Cardiac surgery operating room in a single cardiovascular center.

PARTICIPANTS

Twenty patients who underwent elective AAA surgery.

INTERVENTIONS

CI_CN and cardiac index measured using 3-dimensional images (CI_3D) were determined simultaneously at 8 points during the surgery. At aortic clamping and unclamping, the authors tested the trending ability of CI_CN using 4-quadrant plot analysis and polar plot analysis.

MEASUREMENTS AND MAIN RESULTS

The authors found a wide limit of agreement between CI_CN and CI_3D (percentage error: 85.0%). The cubic splines, which show the relationship between systemic vascular resistance index and percentage CI discrepancy [(CI_CN-CI_3D)/CI_3D], were sloped positively. Four-quadrant plot analysis showed poor trending ability for CI_CN at both aortic clamping and unclamping (concordance rate: 29.4% and 57.9%, respectively). In the polar plot analysis, the concordance rates at aortic clamping and unclamping were 15.0% and 35.0%, respectively.

CONCLUSIONS

CI_CN is not interchangeable with CI_3D in patients undergoing AAA surgery. The trending ability for CI_CN at aortic clamping and unclamping was below the acceptable limit. These inaccuracies might be secondary to the high systemic vascular resistance index during AAA surgery.

Anesthetic management of modified electroconvulsive therapy for a patient with coronary aneurysms: a case report

Background

Modified electroconvulsive therapy (m-ECT) is utilized worldwide as an effective treatment for drug-resistant psychiatric disorders. However, during m-ECT, treatment of hypotension and hypertension in response to rapid hemodynamic changes is required. We used noninvasive continuous blood pressure monitoring system for continuous hemodynamic measurement during m-ECT.

Case presentation

The patient was a 77-year-old man with depression complicated by coronary artery aneurysms (CAAs). We managed general anesthesia during m-ECT by using the ClearSight™ system (Edwards Lifesciences Corp, Irvine, CA, USA) for hemodynamic measurement. As a result, we performed a total of 10 m-ECTs. No rupture of CAAs or myocardial ischemia occurred and depressive symptoms improved.

Conclusion

We successfully managed the anesthesia in m-ECT for a depressed patient with CAAs without complications by using the ClearSight™ system, which was used for the effective management of circulatory fluctuations.