Finger cuff versus invasive and noninvasive arterial pressure measurement in pregnant patients with obesity.

BACKGROUND: Pregnant patients with obesity may have compromised noninvasive blood pressure (NIBP) measurement. We assessed the accuracy and trending ability of the ClearSight™ finger cuff (FC) with invasive arterial monitoring (INV) and arm NIBP, in obese patients having cesarean delivery. METHODS: Participants were aged ≥18 years, ≥34 weeks gestation, and body mass index (BMI) ≥ 40 kg m-2. FC, INV, and NIBP measurements were obtained across 5-min intervals. The primary outcome was agreement of FC measurements with those of the reference standard INV, using modified Bland-Altman plots. Secondary outcomes included comparisons between FC and NIBP and NIBP versus INV, with four-quadrant plots performed to report discordance rates and evaluate trending ability. RESULTS: Twenty-three participants had a median (IQR) BMI of 45 kg m-2 (44-48). When comparing FC and INV the mean bias (SD, 95% limits of agreement) for systolic blood pressure (SBP) was 16 mmHg (17, -17.3 to 49.3 mmHg), for diastolic blood pressure (DBP) -0.2 mmHg (10.5, -20.7 to 20.3), and for mean arterial pressure (MAP) 5.2 mmHg (11.1, -16.6 to 27.0 mmHg). Discordance occurred in 54 (26%) pairs for SBP, 41 (23%) for DBP, and 41 (21.7%) for MAP. Error grid analysis showed 92.1% of SBP readings in Zone A (no-risk zone). When comparing NIBP and INV, the mean bias (95% limits of agreement) for SBP was 13.0 mmHg (16.7, -19.7 to 29.3), for DBP 5.9 mmHg (11.9, -17.4 to 42.0), and for MAP 8.2 mmHg (11.9, -15.2 to 31.6). Discordance occurred in SBP (84 of 209, 40.2%), DBP (74 of 187, 39.6%), and MAP (63 of 191, 33.0%). CONCLUSIONS: The FC and NIBP techniques were not adequately in agreement with INV. Trending capability was better for FC than NIBP. Clinically important differences may occur in the setting of the perfusion-dependent fetus.

Comparison of the ClearSight™ finger cuff monitor versus invasive arterial blood pressure measurement in elective cardiac surgery patients: a prospective observational study.

PURPOSE: To determine the acceptability of the ClearSight™ system (Edwards Lifesciences Corp., Irvine, CA, USA) for continuous blood pressure monitoring during elective cardiac surgery compared with arterial catheterization. METHODS: We enrolled 30 patients undergoing elective cardiac surgery in a prospective observational study. Blood pressure measurements were recorded every 10 sec intraoperatively. We determined agreement based on the Association for the Advancement of Medical Instrumentation (AAMI) recommendations. Statistical analysis included fixed bias (difference of measurements between methods), percentage error (accuracy between ClearSight measurement and expected measurement from arterial line), and interchangeability (ability to substitute ClearSight monitor without effecting overall outcome of analysis). We used a paired samples t test to compare the time required for placing each monitor. RESULTS: We found fixed bias in the differences between the ClearSight monitor and invasive arterial blood pressure measurement in systolic blood pressure (SBP; mean difference, 8.7; P < 0.001) and diastolic blood pressure (DBP; mean difference, -2.2; P < 0.001), but not in mean arterial pressure (MAP; mean difference, -0.5; P < 0.001). Bland-Altman plots showed that the means of the limits of agreement were greater than 5 mm Hg for SBP, DBP, and MAP. The percentage errors for SBP, DBP, and MAP were lower than the cutoff we calculated from the invasive arterial blood pressure measurements. Average interchangeability rates were 38% for SBP, 50% for DBP, and 50% for MAP. Placement of the ClearSight finger cuff was significantly faster compared with arterial catheterization (mean [standard deviation], 1.7 [0.6] min vs 5.6 [4.1] min; P < 0.001). CONCLUSIONS: In this prospective observational study, we did not find the ClearSight system to be an acceptable substitute for invasive arterial blood pressure measurement in elective cardiac surgery patients according to AAMI guidelines. Nevertheless, based on statistical standards, there is evidence to suggest otherwise. STUDY REGISTRATION: ClinicalTrials.gov ( NCT05825937 ); first submitted 11 April 2023.

RéSUMé: OBJECTIF: Notre objectif était de déterminer l'acceptabilité du système ClearSight™ (Edwards Lifesciences Corp., Irvine, CA, USA) pour la surveillance continue de la tension artérielle pendant une chirurgie cardiaque non urgente par rapport au cathétérisme artériel. MéTHODE: Nous avons recruté 30 patient·es bénéficiant d'une chirurgie cardiaque non urgente pour une étude observationnelle prospective. Les mesures de la tension artérielle ont été enregistrées toutes les 10 sec en période peropératoire. Nous avons déterminé l'accord sur la base des recommandations de l'Association for the Advancement of Medical Instrumentation (AAMI). L'analyse statistique comprenait le biais fixe (différence de mesures entre les méthodes), le pourcentage d'erreur (précision entre la mesure ClearSight et la mesure attendue à partir de la ligne artérielle), et l'interchangeabilité (capacité de remplacer la mesure invasive par le moniteur ClearSight sans affecter le résultat global de l'analyse). Nous avons utilisé des échantillons t appariés pour comparer le temps nécessaire à la mise en place de chaque moniteur. RéSULTATS: Nous avons constaté un biais fixe dans les différences entre le moniteur ClearSight et la mesure invasive de la tension artérielle dans la tension artérielle systolique (TAS; différence moyenne, 8,7; P < 0,001) et la tension artérielle diastolique (TAD; différence moyenne, −2,2; P < 0,001), mais pas dans la tension artérielle moyenne (TAM; différence moyenne, −0,5; P < 0,001). Les graphiques de Bland-Altman ont montré que les moyennes des limites d'accord étaient supérieures à 5 mm Hg pour la TAS, la TAD et la TAM. Les pourcentages d'erreurs pour la TAS, la TAD et la TAM étaient inférieurs au seuil que nous avons calculé à partir des mesures invasives de la tension artérielle. Les taux d'interchangeabilité moyens étaient de 38 % pour la TAS, de 50 % pour la TAD et de 50 % pour la TAM. La mise en place du moniteur digital ClearSight a été significativement plus rapide que celle du cathétérisme artériel (moyenne [écart type], 1,7 [0,6] min vs 5,6 [4,1] min; P < 0,001). CONCLUSION: Dans cette étude observationnelle prospective, nous n'avons pas trouvé que le système ClearSight était un substitut acceptable à la mesure invasive de la tension artérielle chez les patient·es de chirurgie cardiaque non urgente, selon les directives de l'AAMI. Néanmoins, sur la base des normes statistiques, il existe des données probantes suggérant le contraire. ENREGISTREMENT DE L'éTUDE: ClinicalTrials.gov ( NCT05825937 ); première soumission le 11 avril 2023.

Continuous Noninvasive Blood Pressure Measurement With "ClearSight" Compared to Standard Intermittent Blood Pressure Measurement in Patients With Peripheral Arterial Disease. Are Potential Differences Influenced by Phenylephrine or Dobutamine?

OBJECTIVES: To investigate the agreement between continuous noninvasive blood pressure measurement with the ClearSight system (cNIBP-CS) and standard intermittent noninvasive blood pressure measurement (iNIBP) in patients with peripheral arterial disease (PAD). Additionally, the influence of vasoactive medication on potential measurement differences was assessed. DESIGN: A secondary analysis of a randomized controlled trial. SETTING: At a university hospital. PARTICIPANTS: Thirty-four patients with PAD undergoing percutaneous transluminal angioplasty of the lower limbs. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Continuous noninvasive blood pressures were measured with the "ClearSight" system and compared to standard iNIBPs. Bland-Altman analysis revealed a mean bias of 13 mmHg (±15) between cNIBP-CS and iNIBP, with 95% limits of agreement (LOA) ranging from -17 to 42 mmHg. When comparing both medication groups, a similar mean bias was found for phenylephrine and dobutamine (12 mmHg [±13] and 13 mmHg [±13], respectively). CONCLUSION: In this study, in patients with PAD, cNIBP-CS showed an underestimation of blood pressure compared to iNIBP in phenylephrine- and dobutamine-treated patients. Compared to previous studies, a larger bias and wider 95% LOA were found.

Current Commonly Used Dynamic Parameters and Monitoring Systems for Perioperative Goal-Directed Fluid Therapy: A Review.

Goal-directed fluid therapy (GDFT) is usually recommended in patients undergoing major surgery and is essential in enhanced recovery after surgery (ERAS) protocols. This fluid regimen is usually guided by dynamic hemodynamic parameters and aims to optimize patients' cardiac output to maximize oxygen delivery to their vital organs. While many studies have shown that GDFT benefits patients perioperatively and can decrease postoperative complications, there is no consensus on which dynamic hemodynamic parameters to guide GDFT with. Furthermore, there are many commercialized hemodynamic monitoring systems to measure these dynamic hemodynamic parameters, and each has its pros and cons. This review will discuss and review the commonly used GDFT dynamic hemodynamic parameters and hemodynamic monitoring systems.

ClearSight™ finger cuff versus invasive arterial pressure measurement in patients with body mass index above 45 kg/m2.

BACKGROUND: Measuring blood pressure in patients with obesity is challenging. The ClearSight™ finger cuff (FC) uses the vascular unloading technique to provide continuous non-invasive blood pressure measurements. We aimed to test the agreement of the FC with invasive radial arterial monitoring (INV) in patients with obesity. METHODS: Participants had a body mass index (BMI) ≥45 kg/m2 and underwent laparoscopic bariatric surgery. FC and INV measurements were obtained simultaneously every 5 min on each patient, following induction of anesthesia. Agreement over time was assessed using modified Bland-Altman plots and error grid analysis permitted clinical interpretation of the results. Four-quadrant plots allowed assessment of concordance in blood pressure changes. RESULTS: The 30 participants had a median (IQR) BMI of 50.2 kg/m2 (IQR 48.3-55.3). The observed bias (SD, 95% limits of agreement) for systolic blood pressure (SBP) was 14.3 mmHg (14.1, -13.4 - 42.0), 5.2 mmHg (10.9, -16.0 - 26.5) for mean arterial pressure (MAP) and 2.6 mmHg (10.8, -18.6 - 23.8) for diastolic blood pressure (DBP). Error grid analysis showed that the proportion of readings in risk zones A-E were 90.8, 6.5, 2.7, 0 and 0% for SBP and 91.4, 4.3, 4.3, 0 and 0% for MAP, respectively. Discordance occurred in ≤8% of pairs for consecutive change in SBP, MAP and DBP. CONCLUSIONS: The vascular unloading technique was not adequately in agreement with radial arterial monitoring. Evaluation in a larger sample is required before recommending this technique for intraoperative monitoring of patients with BMI ≥45 kg/m2.

Effect of Systemic Vascular Resistance on the Reliability of Noninvasive Hemodynamic Monitoring in Cardiac Surgery.

OBJECTIVE: To assess the effect of systemic vascular resistance (SVR) on the reliability of the ClearSight system (Edwards Lifesciences, Irvine, CA) for measuring blood pressure (BP) and cardiac output (CO). DESIGN: Observational study. SETTING: University hospital. PARTICIPANTS: Twenty-five patients undergoing cardiac surgery. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: BP, measured using ClearSight and an arterial line, and CO, measured using ClearSight and a pulmonary artery catheter, were recorded before (T1) and two minutes after phenylephrine or ephedrine administration. Bland-Altman analysis was used to compare BP and CO measurements at T1. A polar plot was used to assess trending abilities. Patients were divided into the following three groups according to the SVR index (SVRI) at T1: low (<1,200 dyne s/cm5/m2), normal (1,200-25,00 dyne s/cm5/m2), and high (>2,500 dyne s/cm5/m2). The bias in BP and CO was -4.8 ± 8.9 mmHg and 0.10 ± 0.81 L/min, respectively, which was correlated significantly with SVRI (p < 0.05). The percentage error in CO was 40.6%, which was lower in the normal SVRI group (33.3%) than the low and high groups (46.3% and 47.7%, respectively). The angular concordance rate was 96.3% and 95.4% for BP and 87.0% and 92.5% for CO after phenylephrine and ephedrine administration, respectively. There was a low tracking ability for CO changes after phenylephrine administration in the low-SVRI group (angular concordance rate 33.3%). CONCLUSION: The ClearSight system showed an acceptable accuracy in measuring BP and tracking BP changes in various SVR states; however, the accuracy of CO measurement and its trending ability in various SVR states was poor.

Non-invasive measurement of pulse pressure variation using a finger-cuff method in obese patients having laparoscopic bariatric surgery.

Pulse pressure variation (PPV) is a dynamic cardiac preload variable used to predict fluid responsiveness. PPV can be measured non-invasively using innovative finger-cuff systems allowing for continuous arterial pressure waveform recording, e.g., the Nexfin system [BMEYE B.V., Amsterdam, The Netherlands; now Clearsight (Edwards Lifesciences, Irvine, CA, USA)] (PPVFinger). However, the agreement between PPVFinger and PPV derived from an arterial catheter (PPVART) in obese patients having laparoscopic bariatric surgery is unknown. We compared PPVFinger and PPVART at 6 time points in 60 obese patients having laparoscopic bariatric surgery in a secondary analysis of a prospective method comparison study. We used Bland-Altman analysis to assess absolute agreement between PPVFinger and PPVART. The predictive agreement for fluid responsiveness between PPVFinger and PPVART was evaluated across three PPV categories (PPV < 9%, PPV 9-13%, PPV > 13%) as concordance rate of paired measurements and Cohen's kappa. The overall mean of the differences between PPVFinger and PPVART was 0.5 ± 4.6% (95%-LoA - 8.6 to 9.6%) and the overall predictive agreement was 72.4% with a Cohen's kappa of 0.53. The mean of the differences was - 0.7 ± 3.8% (95%-LoA - 8.1 to 6.7%) without pneumoperitoneum in horizontal position and 1.1 ± 4.8% (95%-LoA - 8.4 to 10.5%) during pneumoperitoneum in reverse-Trendelenburg position. The absolute agreement and predictive agreement between PPVFinger and PPVART are moderate in obese patients having laparoscopic bariatric surgery.

Accuracy and Trending Ability of Blood Pressure and Cardiac Index Measured by ClearSight System in Patients With Reduced Ejection Fraction.

OBJECTIVES: To investigate the accuracy and trending ability of ClearSight (Edwards Lifesciences, Irvine, CA) in patients with reduced ejection fraction (<55%) undergoing off-pump coronary artery bypass graft (CABG) surgery by comparing the ClearSight-derived cardiac index (CICS) with the cardiac index measured with thermodilution using a pulmonary artery catheter. In addition, the accuracy and trending ability of ClearSight for blood pressure measurement was investigated by comparing the mean arterial pressure (MAP) derived by ClearSight (MAPcs) with invasive intra-arterial pressure. DESIGN: Prospective clinical study. DESIGN: Cardiac surgery operating room in a single cardiovascular center. PARTICIPANTS: The study comprised 20 patients who underwent elective CABG surgery. INTERVENTIONS: MAP and cardiac index were measured simultaneously at 6 time points intraoperatively. Trending ability was investigated at the following 2 points: (1) before and after placing the patient in the Trendelenburg position and (2) before and after atrial pacing with a targeted heart rate increase of 20%. MEASUREMENTS AND MAIN RESULTS: Bland-Altman analysis showed that the percentage error between CICS and the cardiac index measured with thermodilution was 40.2% and the percentage error between MAPcs and MAP was 24.6%. Four-quadrant plot analysis showed that the tracking ability of CICS with the Trendelenburg position and atrial pacing was below the good trending ability cutoff (92%). However, the concordance rate of the 4-quadrant plot analysis showed a good trending ability for MAPcs. The polar plot analysis showed the same trend. CONCLUSIONS: CICS was not sufficiently accurate in patients with reduced ejection fraction undergoing off-pump CABG surgery. However, ClearSight was clinically acceptable for MAP regarding its accuracy and trending ability in patients with reduced ejection fraction.

Comparison between hemodynamic effects of propofol and thiopental during general anesthesia induction with remifentanil infusion: a double-blind, age-stratified, randomized study.

PURPOSE: Propofol is commonly used with remifentanil for induction of general anesthesia (GA); however, it often leads to hypotension. Intraoperative hypotension is associated with postoperative adverse events. By contrast, thiopental has less negative inotropic effects on hemodynamics compared to propofol, which could be suitable to prevent hypotension during GA induction. In the present age-stratified, randomized, assessor-blinded study, using the ClearSight® system, we compared the hemodynamic effects of propofol and thiopental during GA induction under remifentanil infusion in non-cardiac surgery. METHODS: Patients were divided into young (20-40 year), middle (41-70 year), and elderly (> 70 year) groups (n = 20, each group). General anesthesia was induced with remifentanil 0.3 µg/kg/min, followed by propofol (2.0, 1.5, and 1.2 mg/kg) or thiopental (5.0, 4.0, and 3.0 mg/kg) in the young, middle, and elderly groups, respectively. The primary outcome was the difference in the decrease in mean arterial blood pressure between patients receiving propofol and thiopental in each age group. The secondary outcomes included other hemodynamic parameters and minimal bispectral index values measured up to 10 min after tracheal intubation. RESULTS: The decrease in mean arterial blood pressure was greater in patients receiving propofol than those receiving thiopental (- 45.4 vs - 26.6 mmHg and - 45.7 vs - 28.9 mmHg, P = 0.003 and 0.007, respectively), whereas no significant difference was observed in the young age group (P = 0.96). CONCLUSIONS: Thiopental is a more suitable agent than propofol for avoiding hypotension during GA induction under remifentanil infusion in the middle and elderly patients.

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

PURPOSE: The ClearSight™ device monitors continuous pressure and cardiac output via pulse contour analysis. ClearSight™, however, may not be reliable in patients with reduced peripheral perfusion caused by high peripheral resistance. This study aimed to elucidate the accuracy and trending ability of ClearSight™ in patients undergoing abdominal aortic aneurysm (AAA) surgery by comparing the ClearSightTM-derived cardiac index (CICS) with that measured using three-dimensional echocardiography (CI3D). METHODS: The study included 20 patients who underwent elective AAA surgery. CICS and CI3D were measured simultaneously at eight time points during the surgery. Trending ability was investigated after aortic clamping and unclamping. We used CI3D as the reference method. RESULTS: Bland-Altman analysis showed a wide limit of agreement between CICS and CI3D (percentage error 41.3%). Subgroup analysis showed a lower percentage error (33.2%) in patients with CI ≥ 2.5 L/min/m2. The cubic splines related to the CI3D and CI discrepancy were negatively sloped, indicating that CI3D had significant influence on the CI discrepancy (p < 0.001). Four-quadrant plot analysis showed that the tracking ability of ClearSight™ after aortic clamping and declamping were clinically unacceptable (81.3% and 78.6%, respectively). Also, the polar plot analysis showed that the concordance rate of ClearSight™ after aortic clamping and declamping were clinically unacceptable (58.3% and 66.7%, respectively). CONCLUSIONS: ClearSight™ was not sufficiently accurate in patients undergoing AAA surgery. The tracking ability of ClearSight™ after aortic clamping was below the acceptable limit.

Impact of non-invasive continuous blood pressure monitoring on maternal hypotension during cesarean delivery: a randomized-controlled study.

PURPOSE: This study aimed to investigate the efficacy of the ClearSight™ system (Edwards Lifesciences, Irvine, CA) for reducing the incidence of hypotension compared with the traditional oscillometric blood pressure monitoring in cesarean delivery under spinal anesthesia. METHODS: Forty patients undergoing cesarean delivery under spinal anesthesia were enrolled. The patients were randomly divided into two groups (Control and ClearSight groups). All patients received spinal anesthesia using 0.5% hyperbaric bupivacaine (11.5 mg) and fentanyl (10 µg). Blood pressure was managed with the same protocol using the ClearSight™ system (ClearSight group) and oscillometric blood pressure monitoring (Control group). Furthermore, we compared the accuracy of the ClearSight™ system with the traditional oscillometric monitoring for blood pressure measurement using Bland-Altman, four-quadrant plot, and polar plot analyses. RESULTS: The incidence of hypotension was significantly lower in the ClearSight group from induction to delivery (45% vs. 0%, p < 0.001) and to the end of surgery (50% vs. 20%, p = 0.049). Intraoperative nausea occurred more frequently in the Control group (45% vs. 10%, p = 0.012). The ClearSight™ system demonstrated acceptable accuracy with a bias of - 4.3 ± 11.7 mmHg throughout the procedure. Four-quadrant analysis revealed an excellent trending ability of the ClearSight™ system with a concordance rate of approximately 95%. In the polar plot analysis, the angular bias and concordance rate were - 13.5° ± 19.0° and 76.9%, respectively. CONCLUSIONS: The accuracy and trending ability of the ClearSight™ system for blood pressure measurement was clinically acceptable in cesarean delivery under spinal anesthesia, leading to reductions in maternal hypotension and nausea.

Risk factors for poor performance in finger cuff non-invasive monitoring of arterial pressure: A prospective multicenter study.

BACKGROUND: Compared to the invasive technique, non-invasive monitoring of arterial pressure favors easier and faster implementation while potentially sacrificing some reliability. This may be particularly true for the Clearsight™ system (Edwards Lifesciences), which enables continuous monitoring. We evaluated the risk factors for its poor performance. METHODS: Patients with an arterial catheter and stable mean arterial pressure (MAP) over a 5-min period were included. Six pairs of invasive and Clearsight measurements of MAP were collected and the bias between the two techniques was calculated. Poor performance of the Clearsight™ system was defined as either a failure to measure and display MAP or displaying an erroneous MAP (individual bias > 5 mmHg). Fingertip perfusion was assessed using the plethysmographic perfusion index (PI) and the capillary refill time (CRT). RESULTS: Among 152 ICU patients (MAP of 81 ± 14 mmHg, norepinephrine in 78 [51%]), 78 (51%) experienced a poor performance of the Clearsight™ system: failure to display MAP in 19 (13%) patients, and erroneous value displayed in 59 (44%). In multivariate analysis, PI ≤ 0.85% (adjusted odds ratio [aOR] = 2.94 [95% confidence interval (95%CI):1.34;6.45]), CRT > 4 s (aOR = 5.28 [95%CI 1.39;20.05]), and the presence of hand edema (aOR = 2.06 [95%CI 1.01;4.21]) were associated with a higher likelihood of poor performance. Cardiac arrhythmia (aOR = 1.39 [95%CI 0.64;3.02]) and other tested variables were not associated with poor performance. CONCLUSIONS: Half of the included patients exhibited poor Clearsight™ system performance. Our results caution against using finger cuff arterial pressure monitoring in patients with low PI (≤0.85%), protracted CRT (>4 s), or hand edema. REGISTRATION: ClinicalTrials.gov, NCT04269382, Dr. G. Muller, February 13, 2020. https://classic. CLINICALTRIALS: gov/ct2/show/NCT04269382.

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.

Detecting Volemic, Cardiac, and Autonomic Responses From Hypervolemia to Normovolemia via Non-Invasive ClearSight Hemodynamic Monitoring During Hemodialysis: An Observational Investigation.

Background: Unstable hemodynamics are not uncommon during hemodialysis (HD), which involves a rapid volume depletion, taking the patient from hypervolemia toward euvolemia. Since uremic patients commonly have cardiovascular comorbidities, hemodynamic changes during HD may reflect interactions among the volemic, cardiac, and autonomic responses to gradual volume depletion during ultrafiltration. Accurate identification of inappropriate responses helps with precisely managing intradialytic hypotension. Recently, the non-invasive ClearSight was reported to be able to detect causes of intraoperative hypotension. In this prospective observational study, we aimed to determine whether ClearSight could be used to detect patterns in stroke volemic, cardiac, and vasoreactive responses during HD. Methods: ClearSight was used to monitor chronic stable patients receiving maintenance HD. Data of mean arterial blood pressure (MAP), heart rate (HR), stroke volume index (SVI), cardiac index (CI), and calculated systemic vascular resistance index (SVRI) were obtained and analyzed to examine patterns in volemic, cardiac, and vasoreactive changes from T0 (before HD) until T8 in 30-min intervals (total 4 h). Results: A total of 56 patients with a mean age of 60.5 years were recruited, of which 40 of them were men. The average ultrafiltration volume at T8 was 2.1 ± 0.8 L. The changes in MAP and HR from T0 to T8 were non-significant. SVI at T7 was significantly lower than that at T1, T2, and T3. CI at T4 to T8 was significantly lower than that at T0. SVRI was significantly higher at T3 to T8 than at T0. Pearson's correlation coefficients between SVI and CI and between SVRI and MAP were positive at all time points. The correlation coefficients between SVRI and SVI and between CI and SVRI were significant and negative for all time points. Conclusion: ClearSight was able to detect patterns in hypervolemia during HD and was well tolerated for 4 h. CI decreased significantly after T4, with slightly decreased SVI. Ultrafiltration volume was not correlated with changes in SVI or CI. The vascular tone increased significantly, and this counteracted the reduced cardiac output after T4. With simultaneous monitoring on SVI, CI, and SVRI during HD, therefore, hypotension could be detected and managed by reducing the filtration rate or administering inotrope or vasopressors. Trial Registration: clinicaltrials.gov, ID: NCT03901794.

Clinical agreement of a novel algorithm to estimate radial artery blood pressure from the non-invasive finger blood pressure.

STUDY OBJECTIVE: A new algorithm was developed that transforms the non-invasive finger blood pressure (BP) into a radial artery BP (B̂PRad), whereas the original algorithm estimated brachial BP (B̂PBra). In this study we determined whether this new algorithm shows better agreement with invasive radial BP than the original one and whether in the operating room this algorithm can be used safely. DESIGN, SETTING AND PATIENTS: This observational study was conducted on thirty-three non-cardiac surgery patients. INTERVENTION AND MEASUREMENTS: Invasive radial and non-invasive finger BP were measured, of the latter B̂PRad and B̂PBra were transformed. Agreement of systolic, mean, and diastolic arterial BP (SAP, MAP, and DAP, respectively) was assessed traditionally with Bland-Altman and trend analysis and clinically safety was quantified with error grid analyses. A bias (precision) of 5 (8) mmHg or less was considered adequate. MAIN RESULTS: Thirty-three patients were included with an average of 676 (314) 20 s segments. For both comparisons, bias (precision) of MAP was within specified criteria, whereas for SAP, precision was higher than 8 mmHg. B̂PRad showed a better agreement than B̂PBra with BPRad for DAP values (bias (precision): 0.7 (6.0) and - 6.4 (4.3) mmHg, respectively). B̂PRad and B̂PBra both showed good concordance in following changes in BPRad (for all parameters overall degree was <7°). There were slightly more measurement pairs of MAP within the no-risk zone for B̂PRad than for B̂PBra (96 vs 77%, respectively). CONCLUSIONS: In this cohort of non-cardiac surgery patients, we found good agreement between BPRad and B̂PRad. Compared to B̂PBra, B̂PRad shows better agreement although clinical implications are small. This trial was registered with ClinicalTrials.gov (https://clinicaltrials.gov/ct2/show/NCT03795831).

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

BACKGROUND: The ClearSight system measures blood pressure non-invasively and determines cardiac output by analyzing the continuous pressure waveform. We performed a multi-center clinical study in China to test the equivalence of cardiac output measured with the ClearSight system (CSCO) and cardiac output measured with the pulmonary artery catheter bolus thermodilution (TDCO) method. METHODS: We included adult patients undergoing cardiac surgery in three Chinese hospitals and measured TDCO and CSCO simultaneously after induction of anesthesia. Hemodynamic stability was required during measurement of TDCO and CSCO. At least four TDCO determinations were performed. The corresponding CSCO was determined as the average over a 30-s period following the injection of each bolus. A data pair for the comparison included the average of three or four accepted TDCO values and the average of the matching CSCO values. Main outcomes included Bland-Altman analysis of bias and standard deviation (SD) and the percentage error (PE). RESULTS: One hundred twenty-five subjects were enrolled, and 122 TDCO and CSCO data pairs were available for analysis. Ninety-five (75.4%) data pairs were collected in hemodynamically stable conditions, mean (SD) CSCO was 4.21 (0.78) l/min, and mean TDCO was 3.90 (0.67) l/min. Bias was 0.32 (0.51) l/min, and PE was 25.2%. Analyzing all 122 data pairs resulted in a mean CSCO of 4.19 (0.82) l/min and a mean TDCO of 3.83 (0.71) l/min. Resulting bias was 0.36 (0.53) l/min, and PE was 26.4%. CONCLUSIONS: CSCO and TDCO agreed with a low systematic bias. Besides, mean PE was well below the pre-defined 30%. Hemodynamic stability only had a small impact on the analysis. We conclude that CSCO is equivalent to TDCO in cardiac surgery patients. The trial was retrospectively registered in ClinicalTrials.gov, identifier NCT03807622 ; January 17, 2019.

The ClearSight System for Postoperative Arterial Blood Pressure Monitoring After Carotid Endarterectomy: A Validation Study.

BACKGROUND: The majority of postoperative events in patients undergoing carotid endarterectomy (CEA) are of hemodynamic origin, requiring preventive strict postoperative arterial blood pressure (BP) control. This study aimed to assess whether BP monitoring with noninvasive beat-to-beat ClearSight finger BP (BPCS) can replace invasive beat-to-beat radial artery BP (BPRAD) in the postoperative phase. METHODS: This study was a single-center clinical validation study using a prespecified study protocol. In 48 patients with symptomatic carotid artery stenosis, BPCS and BPRAD were monitored ipsilateral in a simultaneous manner during a 6-hour period on the recovery unit following CEA. Primary endpoints were accuracy and precision of BP derived by ClearSight (Edward Lifesciences, Irvine, CA) vs. the reference standard (Arbocath 20 G, Hospira, Lake Forest, IL) to investigate if BPCS is a reliable noninvasive alternative for BP monitoring postoperatively in CEA patients. Validation was guided by the standard set by the Association for Advancement of Medical Instrumentation (AAMI), considering a BP-monitor adequate when bias (precision) is <5 (8) mm Hg. Secondary endpoint was percentage under- and overtreatment, defined as exceedance of individual postoperative systolic BP threshold by BPRAD or BPCS in contrast to BPCS or BPRAD, respectively. RESULTS: The bias (precision) of BPCS compared to BPRAD was -10 (13.6), 8 (7.2) and 4 (7.8) mm Hg for systolic, diastolic and mean arterial pressure (MAP), respectively. Based on BPCS, undertreatment was 5.6% and overtreatment was 2.4%; however, percentages of undertreatment quadrupled for lower systolic BP thresholds. CONCLUSIONS: Noninvasive MAP, but not systolic and diastolic BP, was similar to invasive BPRAD during postoperative observation following CEA, based on AAMI criteria. However, as systolic BP is currently leading in postoperative monitoring to adjust BP therapy on, BPCS is not a reliable alternative for BPRAD.

The Use of Non-Invasive Continuous Blood Pressure Measuring (ClearSight®) during Central Neuraxial Anaesthesia for Caesarean Section-A Retrospective Validation Study.

The close monitoring of blood pressure during a caesarean section performed under central neuraxial anaesthesia should be the standard of safe anaesthesia. As classical oscillometric and invasive blood pressure measuring have intrinsic disadvantages, we investigated a novel, non-invasive technique for continuous blood pressure measuring. Methods: In this monocentric, retrospective data analysis, the reliability of continuous non-invasive blood pressure measuring using ClearSight® (Edwards Lifesciences Corporation) is validated in 31 women undergoing central neuraxial anaesthesia for caesarean section. In addition, patients and professionals evaluated ClearSight® through questioning. Results: 139 measurements from 11 patients were included in the final analysis. Employing Bland-Altman analyses, we identified a bias of -10.8 mmHg for systolic, of -0.45 mmHg for diastolic and of +0.68 mmHg for mean arterial blood pressure measurements. Pooling all paired measurements resulted in a Pearson correlation coefficient of 0.7 for systolic, of 0.67 for diastolic and of 0.75 for mean arterial blood pressure. Compensating the interindividual differences in linear regressions of the paired measurements provided improved correlation coefficients of 0.73 for systolic, of 0.9 for diastolic and of 0.89 for mean arterial blood pressure measurements. Discussion: Diastolic and mean arterial blood pressure are within an acceptable range of deviation from the reference method, according to the Association for the Advancement of Medical Instrumentation (AAMI) in the patient collective under study. Both patients and professionals prefer ClearSight® to oscillometric blood pressure measurement in regard of comfort and handling.