Four-quadrant Plot Research Articles

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

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. 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. 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%). 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.

Effect of hyperbilirubinemia on the accuracy of continuous non-invasive hemoglobin measurements in liver transplantation recipients

This study evaluated the effect of hyperbilirubinemia on the accuracy of continuous non-invasive hemoglobin (SpHb) measurements in liver transplantation recipients. Overall, 1465 SpHb and laboratory hemoglobin (Hb) measurement pairs (n = 296 patients) were analyzed. Patients were grouped into normal (< 1.2 mg/dL), mild-to-moderate (1.2–3.0 mg/dL), and severe (> 3.0 mg/dL) hyperbilirubinemia groups based on the preoperative serum total bilirubin levels. Bland–Altman analysis showed a bias of 0.20 (95% limit of agreement, LoA: − 2.59 to 3.00) g/dL, 0.98 (95% LoA: − 1.38 to 3.35) g/dL, and 1.23 (95% LoA: − 1.16 to 3.63) g/dL for the normal, mild-to-moderate, and severe groups, respectively. The four-quadrant plot showed reliable trending ability in all groups (concordance rate > 92%). The rates of possible missed transfusion (SpHb > 7.0 g/dL for Hb < 7.0 g/dL) were higher in the hyperbilirubinemia groups (2%, 7%, and 12% for the normal, mild-to-moderate, and severe group, respectively. all P < 0.001). The possible over-transfusion rate was less than 1% in all groups. In conclusion, the use of SpHb in liver transplantation recipients with preoperative hyperbilirubinemia requires caution due to the positive bias and high risk of missed transfusion. However, the reliable trending ability indicated its potential use in clinical settings.

Reliability of Bioreactance and Pulse-Power Analysis in Measuring Cardiac Index During Open Abdominal Aortic Surgery

To investigate the accuracy, precision, and trending ability of noninvasive bioreactance-based Starling SV and the mini invasive pulse-power device LiDCOrapid as compared to thermodilution cardiac output (TDCO) as measured by pulmonary artery catheter when assessing cardiac index (CIx) in the setting of elective open abdominal aortic (AA) surgery. A prospective method-comparison study. Oulu University Hospital, Finland. Forty patients undergoing elective open abdominal aortic surgery. Intraoperative CI measurements were obtained simultaneously with TDCO and the study monitors, resulting in 627 measurement pairs with Starling SV and 497 with LiDCOrapid. The Bland-Altman method was used to investigate the agreement among the devices, and four-quadrant plots with error grids were used to assess trending ability. The agreement between TDCO and Starling SV was associated with a bias of 0.18 L/min/m2 (95% confidence interval [CI] = 0.13 to 0.23), wide limits of agreement (LOA = -1.12 to 1.47 L/min/m2), and a percentage error (PE) of 63.7 (95% CI = 52.4-71.0). The agreement between TDCO and LiDCOrapid was associated with a bias of -0.15 L/min/m2 (95% CI = -0.21 to -0.09), wide LOA (-1.56 to 1.37), and a PE of 68.7 (95% CI = 54.9-79.6). The trending ability of neither device was sufficient. The CI measurements achieved with Starling SV and LiDCOrapid were not interchangeable with TDCO, and the ability to track changes in CI was poor. These results do not support the use of either study device in monitoring CI during open AA surgery.

Automatic assessment of left ventricular function for hemodynamic monitoring using artificial intelligence and transesophageal echocardiography.

We have developed a method to automatically assess LV function by measuring mitral annular plane systolic excursion (MAPSE) using artificial intelligence and transesophageal echocardiography (autoMAPSE). Our aim was to evaluate autoMAPSE as an automatic tool for rapid and quantitative assessment of LV function in critical care patients. In this retrospective study, we studied 40 critical care patients immediately after cardiac surgery. First, we recorded a set of echocardiographic data, consisting of three consecutive beats of midesophageal two- and four-chamber views. We then altered the patient's hemodynamics by positioning them in anti-Trendelenburg and repeated the recordings. We measured MAPSE manually and used autoMAPSE in all available heartbeats and in four LV walls. To assess the agreement with manual measurements, we used a modified Bland-Altman analysis. To assess the precision of each method, we calculated the least significant change (LSC). Finally, to assess trending ability, we calculated the concordance rates using a four-quadrant plot. We found thatautoMAPSE measured MAPSE in almost every set of two- and four-chamber views (feasibility 95%). It took less than a second to measure and average MAPSE over three heartbeats. AutoMAPSE had a low bias (0.4mm) and acceptable limits of agreement (-3.7 to 4.5mm). AutoMAPSE was more precise than manual measurements if it averaged more heartbeats. AutoMAPSE had acceptable trending ability (concordance rate 81%) during hemodynamic alterations. In conclusion, autoMAPSE is feasible as an automatic tool for rapid and quantitative assessment of LV function, indicating its potential for hemodynamicmonitoring.

Design of Smart Underwear Nursing Service System to Assist Elderly Walking based on Kano Model

This study was to design an intelligent underwear nursing service system that can assist the elderly in walking according to their original demand for intelligent underwear fall prevention. The research proposed an intelligent underwear nursing service system that integrates the App through the Kano model, which was analyzed with the help of the Four-Quadrant Scatter Model Plot model diagram. Monitoring Service Interaction Subsystem, Monitoring Sports, and Health Management of the intelligent nursing service system. This result indicated that the demand satisfaction rating that the smart underwear nursing service system assists elderly walking was scientific, effective, and fulfilled the needs of elderly users.

Comparison of parameter types for the calibration of noninvasive continuous cardiac output monitoring of patients undergoing lumbar spinal surgery in the prone position.

Cardiac output (CO) decreases on reversing the patient's position to the prone position. Estimated continuous cardiac output (esCCO) systems can noninvasively and continuously monitor CO calibrated by patient information or transesophageal echocardiogram (TEE). To compare the accuracy, precision, and trending ability of two calibration methods of CO estimation in patients in prone position. The CO estimates calibrated by TEE (esT) and patient information (esP) of 26 participants were included. CO was collected at four time points. The accuracy and precision of agreement were evaluated using the Bland-Altman method. A four-quadrant plot was used for trending ability analysis. The bias between esP and TEE and between esT and TEE was 0.2594 L/min (95% limits of agreement (LoA): -1.8374 L/min to 2.3562 L/min) and 0.0337 L/min (95% LoA: -0.7381 L/min to 0.8055 L/min), respectively. A strong correlation was found between ΔesP and ΔTEE (p< 0.001, CCC = 0.700) and between ΔesT and ΔTEE (p< 0.001, CCC = 0.794). The concordance rates between ΔesP and ΔTEE and between ΔesT and ΔTEE were 91.9% and 97.1%, respectively. Despite limited accuracy and precision, esP showed acceptable trending ability. The trending ability of esCCO calibrated by the reference TEE value was comparable with that of TEE.

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

BackgroundBased 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).MethodsThis 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.ResultsFrom 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.ConclusionsDuring LDLT, CI and SVR demonstrated poor interchangeability, while SAP and MAP exhibited acceptable interchangeability between ClearSight™ and FAC.

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

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). 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. 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. 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.

Right Case, Right Time: Which Procedures Best Differentiate General Surgery Trainees’ Operative Performance?

Assessing surgical trainee operative performance is time- and resource-intensive. To maximize the utility of each assessment, it is important to understand which assessment activities provide the most information about a trainee's performance. The objective of this study is to identify the procedures that best differentiate performance for each general surgery postgraduate year (PGY)-level, leading to recommendations for targeted assessment. The Society for Improving Medical Professional Learning (SIMPL) operative performance ratings were modeled using a multilevel Rasch model which identified the highest and lowest performing trainees for each PGY-level. For each procedure within each PGY-level, a procedural performance discrimination index was calculated by subtracting the proportion of "practice-ready" ratings of the lowest performing trainees from the proportion of "practice-ready" ratings of the highest performing trainees. Four-quadrant plots were created using the median procedure volume and median discrimination index for each PGY-level. All procedures within the upper right quadrant were considered "highly differentiating, high volume" procedures. This study was conducted across 70 general surgical residency programs who are members of the SIMPL collaborative. A total of 54,790 operative performance evaluations of categorical general surgery trainees were collected between 2015 and 2021. Trainees who had at least 1 procedure in common were included. Procedures with less than 25 evaluations per training year were excluded. The total number of evaluations per procedure ranged from 25 to 2,131. Discrimination values were generated for 51 (PGY1), 54 (PGY2), 92 (PGY3), 105 (PGY4), and 103 (PGY5) procedures. Using the above criteria, a total of 12 (PGY1), 15 (PGY2), 22 (PGY3), 21 (PGY4), and 28 (PGY5) procedures were identified as highly differentiating, high volume procedures. Our study draws on national data to identify procedures which are most useful in differentiating trainee operative performance at each PGY-level. This list of procedures can be used to guide targeted assessment and improve assessment efficiency.

Evaluation of the accuracy of oscillometric non-invasive blood pressure measurement at the ankle in children during general anesthesia.

This study aimed to evaluate the accuracy of oscillometric blood pressure measurement at the ankle in children using invasive blood pressure as reference standard. This prospective observational study included children undergoing noncardiac surgery. Paired radial invasive and ankle non-invasive blood pressure measurements were obtained. Delta blood pressure was calculated as the difference between two consecutive readings. The primary outcome was the mean bias and agreement between the two methods using the Bland-Altman analysis. The ISO standard was fulfilled if the mean bias between the two methods was ≤ 5 ± 8 mmHg. Other outcomes included the trending ability of ankle blood pressure using the four-quadrant plot and the accuracy of ankle measurement to detect hypotension using area under receiver operating characteristic curve (AUC) analysis. We analyzed 683 paired readings from 86 children. The mean bias between the two methods for systolic, diastolic, and mean blood pressure (SBP, DBP, MAP) was - 7.2 ± 10.7, 4.5 ± 12.8, and - 1.8 ± 8.2 mmHg, respectively. The concordance rate of ankle blood pressure was 72%, 71%, and 77% for delta SBP, DBP and MAP, respectively. The AUC (95% confidence interval) for ankle MAP ability to detect hypotension was 0.91 (0.89-0.93) with negative predictive value of 100% at cut-off value ≤ 70 mmHg, We concluded that in pediatric population undergoing noncardiac surgery, ankle blood pressure was not interchangeable with the corresponding invasive readings with the ankle MAP having the least bias compared to SBP and DBP. An ankle MAP > 70 mmHg can exclude hypotension with negative predictive value of 100%.

Reliability of bioreactance and pulse power analysis in measuring cardiac index during cytoreductive abdominal surgery with hyperthermic intraperitoneal chemotherapy (HIPEC)

PurposeVarious malignancies with peritoneal carcinomatosis are treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC). The hemodynamic instability resulting from fluid balance alterations during the procedure necessitates reliable hemodynamic monitoring. The aim of the study was to compare the accuracy, precision and trending ability of two less invasive hemodynamic monitors, bioreactance-based Starling SV and pulse power device LiDCOrapid with bolus thermodilution technique with pulmonary artery catheter in the setting of cytoreductive surgery with HIPEC.MethodsThirty-one patients scheduled for cytoreductive surgery were recruited. Twenty-three of them proceeded to HIPEC and were included to the study. Altogether 439 and 430 intraoperative bolus thermodilution injections were compared to simultaneous cardiac index readings obtained with Starling SV and LiDCOrapid, respectively. Bland-Altman method, four-quadrant plots and error grids were used to assess the agreement of the devices.ResultsComparing Starling SV with bolus thermodilution, the bias was acceptable (0.13 l min− 1 m− 2, 95% CI 0.05 to 0.20), but the limits of agreement were wide (− 1.55 to 1.71 l min− 1 m− 2) and the percentage error was high (60.0%). Comparing LiDCOrapid with bolus thermodilution, the bias was acceptable (− 0.26 l min− 1 m− 2, 95% CI − 0.34 to − 0.18), but the limits of agreement were wide (− 1.99 to 1.39 l min− 1 m− 2) and the percentage error was high (57.1%). Trending ability was inadequate with both devices.ConclusionStarling SV and LiDCOrapid were not interchangeable with bolus thermodilution technique limiting their usefulness in the setting of cytoreductive surgery with HIPEC.

Study of the accuracy of a radial arterial pressure waveform cardiac output measurement device after cardiac surgery

BackgroundLess invasive monitoring, such as radial arterial pulse contour analysis (ProAQT® sensor), represents an alternative when hemodynamic monitoring is necessary to guide postoperative management and invasive monitoring is not technically feasible. The aim of the study is to evaluate the accuracy of the ProAQT® sensor cardiac output measurements in comparison with Pulmonary Artery Catheter (PAC) during the postoperative course of patients who underwent cardiac surgery with cardiopulmonary bypass.Case presentationProspective observational study in a Surgical Intensive Care Unit of a tertiary university hospital. Ten patients with a mean age of 73.5 years were included. The main comorbidities were hypertension, diabetes, dyslipidemia and the preoperative left ejection fraction was 43.8 ± 14.5%. Regarding the type of surgery, six patients underwent valve surgery, two underwent coronary artery bypass grafting and two underwent aortic surgery. The cardiac index measured simultaneously by the ProAQT® sensor was compared with the PAC. The parameters were evaluated at predefined time points during the early postoperative courses (6 h, 12 h, 24 h, 48 h and 72 h). The degree of agreement with the cardiac index between the PAC and the ProAQT® sensor along the time points was measured using the concordance correlation coefficient, Bland–Altman analysis, and four-quadrant plot. Sixty-three pairs of measurements were analyzed. We showed that measurements of cardiac index were slightly higher with PAC (β ̂ = − 0.146, p-value = 0.094). The concordance correlation coefficient for the additive model of cardiac index was 0.64 (95% Confidence Interval: 0.36, 0.82), indicating a high concordance between both sensors. Bland-Altmann analysis showed a mean bias of 0.45 L·min−1·m−2, limits of agreement from − 1.65 to 2.3 L·min−1·m−2, and percentage of error was 82.5%. Four-quadrant plot of changes in cardiac index showed a good concordance rate (75%), which increases after applying the exclusion zone (87%).ConclusionsIn patients undergoing cardiac surgery, the ProAQT® sensor may be useful to monitor cardiac index during the postoperative period, especially when more invasive monitoring is not possible.

RELIABILITY OF BIOREACTANCE AND PULSE POWER ANALYSIS IN MEASURING CARDIAC INDEX DURING OPEN ABDOMINAL AORTIC SURGERY

<h3>Objective</h3> Pulmonary artery catheter (PAC) is considered as the gold standard for measuring cardiac output, but less invasive monitors have recently been developed. We compared the accuracy, precision and trending ability of non-invasive bioreactance-based Starling SV and mini-invasive pulse power device LiDCOrapid to bolus thermodilution technique with pulmonary artery catheter (TDCO) when measuring cardiac index (CI) in the setting of open abdominal aortic surgery. <h3>Design and Methods</h3> Forty-one patients undergoing open abdominal aortic surgery were monitored with Starling SV, LiDCOrapid and TDCO during surgery, resulting in 627 simultaneous CI measurements. We used the Bland-Altman method and percentage error to investigate the agreement between the devices and four-quadrant plots with error grids to assess the trending ability. <h3>Results</h3> The agreement between TDCO and Starling SV was associated with a bias of 0.18 L/min/m2 (95% confidence interval, 95% CI 0.13 to 0.23), wide limits of agreement (LOA, -1.12 to 1.47 L/min/m2) and a percentage error (PE) of 63.7 (95% CI 52.4-71.0). (Figure 1a) The agreement between TDCO and LiDCOrapid was associated with a bias of -0.15 L/min/m2 (95% CI -0.21 to -0.09), wide LOA (-1.56 to 1.37) and PE of 68.7 (95% CI 54.9-79.6). (Figure 1b) Trending abilities were not acceptable, since with Starling SV only 33.6% and with LiDCOrapid only 41.2 % of the measurements changed in the same direction to the same extent as with TDCO. <h3>Conclusions</h3> CI measurements with Starling SV and LiDCOrapid were not interchangeable with TDCO, and their ability to track changes in CI was poor. These results do not support their use in monitoring CI reliably during open abdominal aortic surgery.

Evaluation of transpulmonary ultrasound dilution cardiac output in piglets: accuracy, precision and trending ability with room temperature injectate

ObjectiveTranspulmonary ultrasound dilution (TPUD) is a minimally invasive technique to measure cardiac output (CO) using a 1 mL kg–1 isotonic 37 °C saline injectate indicator. The objective was to evaluate the performance of TPUD using a room temperature saline injectate. Study designProspective experimental trial. AnimalsA total of seven anesthetized male Yorkshire piglets. MethodsPiglets aged 1 month and weighing 7.7–9.0 kg were anesthetized with detomidine–ketamine–hydromorphone–isoflurane and a pulmonary artery flow probe (PAFP) placed via a median sternotomy. The thoracic cavity remained open during measurement of CO by PAFP and TPUD. The TPUD indicators of 1 mL kg–1 0.9% saline at 37 °C and 20 °C were compared during infusions of phenylephrine and dobutamine, blood withdrawal and replacement. Bias, limits of agreement (LoAs) and percentage error (PE) between each iteration of PAFP and TPUD were measured with Bland–Altman plots. Trending ability via concordance, angular bias and radial LoA were compared. ResultsBland–Altman plots showed negligible bias with varying LoAs. PEs of 22% and 38% were found for 37 °C and 20 °C saline injectates, respectively. In the four-quadrant plots, the concordance rate was 94% and 100% for measurements obtained with 37 °C and 20 °C saline injectates, respectively. Angular bias for both were < ±5 °, with radial LoA < ±7 °. ConclusionsTPUD was accurate when using 1 mL kg–1 of isotonic saline at 37 °C in a range of CO within 0.2–0.8 L minute–1, and it reliably tracked positive and negative changes in CO. Room temperature (20 °C) indicator was less accurate but equally able to track direction of changes in CO. Clinical relevanceThe use of room temperature injectates allows an easy, readily available clinical application of TPUD CO monitoring while preserving the trending ability of the monitor.

A new noninvasive finger sensor (NICCI system) for continuous blood pressure and pulse pressure variation monitoring: A method comparison study in patients having neurosurgery.

The NICCI system (Getinge, Gothenburg, Sweden) is a new noninvasive haemodynamic monitoring system using a finger sensor. We aimed to investigate the performance of the NICCI system to measure blood pressure and pulse pressure variation compared with intra-arterial measurements. A prospective method comparison study. University Medical Center Hamburg-Eppendorf, Hamburg, Germany. Forty-seven neurosurgery patients. We performed a method comparison study in 47 neurosurgery patients to compare NICCI blood pressure measurements (BP NICCI ) with intra-arterial blood pressure measurements (BP ART ) (Bland-Altman analysis, four-quadrant plot, error grid analysis) and NICCI pulse pressure variation measurements (PPV NICCI ) with pulse pressure variation calculated manually from the intra-arterial blood pressure waveform (PPV ART ) (Bland-Altman analysis, predictive agreement, Cohen's kappa). The mean of the differences ± standard deviation (95% limits of agreement) between BP NICCI and BP ART was 11 ± 10 mmHg (-8 to 30 mmHg) for mean blood pressure (MBP), 3 ± 12 mmHg (-21 to 26 mmHg) for systolic blood pressure (SBP) and 12 ± 10 mmHg (-8 to 31 mmHg) for diastolic blood pressure (DBP). In error grid analysis, 54% of BP NICCI and BP ART MBP measurement pairs were classified as 'no risk', 43% as 'low risk', 3% as 'moderate risk' and 0% as 'significant risk' or 'dangerous risk'. The mean of the differences between PPV NICCI and PPV ART was 1 ± 3% (-4 to 6%). The predictive agreement between PPV NICCI and PPV ART was 80% and Cohen's kappa was 0.55. The absolute agreement between BP NICCI and BP ART was not clinically acceptable. We recommend not using the current version of the NICCI system for blood pressure monitoring during surgery. The absolute agreement between PPV NICCI and PPV ART was clinically acceptable with moderate predictive agreement regarding pulse pressure variation categories. The NICCI system needs to be further developed and re-evaluated when an improved version is available. The study was registered in the German Clinical Trials Register (DRKS00023188) on 2 October 2020.

Femoral Pulse Pressure Variation Is Not Interchangeable with Radial Pulse Pressure Variation during Living Donor Liver Transplantation.

The radial artery is commonly used as the site measuring pulse pressure variation (PPV) during surgery. Accurate measurement of circulating blood volume and timely interventions to maintain optimal circulating blood volume is important to deliver sufficient oxygen to tissues and organs. It has not rather than never studied in patients undergoing liver transplantation whether PPV measured at peripheral sites, such as the radial artery, do represent central PPV for evaluating blood volume. In this retrospective study, 51 liver transplant recipients were enrolled. The two PPVs had been automatically recorded every minute in electrical medical records. A total 1878 pairs of the two PPVs were collected. The interchangeability of PPV measured at the radial and the femoral artery was analyzed by using the Bland–Altman plot, four-quadrant plot, Cohen’s kappa (k), and receiver operating curve. The bias and limits of agreement of the two PPVs were −1.3% and −8.8% to 6.2%, respectively. The percentage error was 75%. The concordance rate was 65%. The Kappa of PPV-radial determining whether PPV-femoral was >13% or ≤13% was 0.64. We found that PPV-radial is not interchangeable with PPV-femoral during liver transplantation. Additionally, PPV-radial failed to reliably track changes of PPV-femoral. Lastly, the clinical decision regarding blood volume status (depletion or not) is significantly different between the two PPVs. Therefore, PPV-femoral may help maintain blood volume circulating to major organs including the newly transplanted liver graft for liver transplant recipients.

Accuracy and trending ability of finger plethysmographic cardiac output monitoring in late pregnancy.

Individuals in late pregnancy are at risk of significant hemodynamic variations, especially during Cesarean delivery. Although non-invasive monitoring might enable the early detection of variations in cardiac output (CO), clinical validation is lacking. In a prospective, single-centerstudy, we measured CO simultaneously with finger plethysmography and transthoracic echocardiography in 100 third-trimester pregnant individuals in the supine and left lateral decubitus (LLD) positions. A Bland-Altman analysis revealed a mean (standard deviation) bias of 1.36 (1.04) L·min-1 in the supine position (95% limits of agreement, -0.68 to 3.4 L·min-1; percent error, 26.6%), indicating overestimation by finger plethysmography. The intra-class correlation coefficient was 0.43 (95% confidence interval [CI], 0.33 to 0.51). Regarding the changes in CO induced by the supine-to-LLD transition, the concordance rate in a four-quadrant plot was 98.3% (95% CI, 91.1 to 99.9%). Our study showed a poor reliability of finger plethysmography for static measurement of CO. Nevertheless, finger plethysmography had a reasonably high concordance rate for the detection of CO changes secondary to positional changes in late-pregnant individuals. STUDY REGISTRATION DATE: www. gov (NCT03735043); registered 8 November 2018.

Perioperative Continuous Noninvasive Cardiac Output Monitoring in Cardiac Surgery Patients by a Novel Capnodynamic Method

To test the clinical performance of a novel continuous noninvasive cardiac output (CO) monitoring based on expired carbon dioxide kinetics in cardiac surgery patients. A prospective feasibility pragmatic clinical study. A single-center, large community hospital. Thirty-two patients undergoing cardiac surgery were studied during the intraoperative (before cardiopulmonary bypass) and postoperative (in the intensive care unit before extubation) periods. CO was measured simultaneously by the continuous capnodynamic method and by transpulmonary thermodilution during changes in the patient's hemodynamic and/or respiratory conditions. The current recommended comparative statistics for CO measurement methods were analyzed, including bias, precision, and percentage error obtained from Bland-Altman analysis, and concordance between methods obtained from the four-quadrant plot analysis to evaluate the trending ability. Bias ± limits of agreement and percentage error were -0.6 (-1.9 to +0.8; 95% CI of 3.73-5.25) L/min and 31% (n=147 measurements) for the intraoperative period, -0.8 (-2.4 to +0.9; 95% CI of 3.03-5.21) L/min and 41% (n=66) for the postoperative period, and -0.6 (-2.1 to +0.8; 95% CI of 3.74-5.00) L/min and 34% (n=213) for the pooled data. The trending analysis obtained a concordance of 82% (n=65) for the intraoperative and 71% (n=24) for the early postoperative periods. Aggregation of both data sets gave a concordance of 79% (n=89). The continuous capnodynamic method was reliable and in good agreement with the reference method, and had an accuracy and trending ability good enough tomake it a possible future alternative for hemodynamic monitoring in the studied population of elective adult cardiac surgery patients.

Continuous measurement of arterial oxygenation in mechanically ventilated horses.

The possibility of accurately and continuously measuring arterial oxygen partial pressure (PaO2 ) in horses may facilitate the management of hypoxaemia during general anaesthesia. The aim of this study was to evaluate the ability of a novel fibreoptic sensor to measure PaO2 (PaO2Sensor ) continuously and in real time in horses undergoing ventilatory manoeuvres during general anaesthesia. In vivo experimental study. Six adult healthy horses were anaesthetised and mechanically ventilated in dorsal recumbency. A fibreoptic sensor was placed in one of the facial arteries through a catheter to continuously measure and record PaO2Sensor . After an alveolar recruitment manoeuvre, a decremental positive end-expiratory pressure (PEEP) titration using 20-minute steps of 5cmH2 O from 20 to 0cmH2 O was performed. An arterial blood sample was collected at 15minutes of ventilation at each PEEP level for PaO2 measurement using an automated blood gas machine (PaO2Ref ). The agreement between PaO2Sensor and PaO2Ref was assessed by Pearson's correlation, Bland-Altman plot and four-quadrant plot analysis. In the last minute of ventilation at each PEEP level, a slow tidal inflation/deflation manoeuvre was performed. The mean relative bias between PaO2Sensor and PaO2Ref was 4% with limits of agreement between -17% and 29%. The correlation coefficient between PaO2Sensor and PaO2Ref was 0.98 (P<.001). The PaO2Sensor and PaO2Ref concordance rate for changes was 95%. Measurements of PaO2Sensor during the slow inflation/deflation manoeuvre at PEEP 15 and 10cmH2 O were not possible because of significant noise on the PaO2 signal generated by a small blood clot. Small sample size. The tested fibreoptic probe was able to accurately and continuously measure PaO2Sensor in anaesthetised horses undergoing ventilatory manoeuvres. A heparinised system in the catheter used by the fibreoptic sensor should be used to avoid blood clots and artefacts in the PaO2 measurements.

Reliability of Bioreactance and Pulse-Power Analysis in Measuring Cardiac Index in Patients Undergoing Cardiac Surgery With Cardiopulmonary Bypass

Less-invasive and continuous cardiac output monitors recently have been developed to monitor patient hemodynamics. The aim of this study was to compare the accuracy, precision, and trending ability of noninvasive bioreactance-based Starling SV and miniinvasive pulse-power device LiDCOrapid to bolus thermodilution technique with a pulmonary artery catheter (TDCO) when measuring cardiac index in the setting of cardiac surgery with cardiopulmonary bypass (CPB). A prospective method-comparison study. Oulu University Hospital, Finland. Twenty patients undergoing cardiac surgery with CPB. Cardiac index measurements were obtained simultaneously with TDCO intraoperatively and postoperatively, resulting in 498 measurements with Starling SV and 444 with LiDCOrapid. The authors used the Bland-Altman method to investigate the agreement between the devices and four-quadrant plots with error grids to assess the trending ability. The agreement between TDCO and Starling SV was qualified with a bias of 0.43 L/min/m2 (95% confidence interval [CI], 0.37-0.50), wide limits of agreement (LOA, -1.07 to 1.94 L/min/m2), and a percentage error (PE) of 66.3%. The agreement between TDCO and LiDCOrapid was qualified, with a bias of 0.22 L/min/m2 (95% CI 0.16-0.27), wide LOA (-0.93 to 1.43), and a PE of 53.2%. With both devices, trending ability was insufficient. The reliability of bioreactance-based Starling SV and pulse-power analyzer LiDCOrapid was not interchangeable with TDCO, thus limiting their usefulness in cardiac surgery with CPB.