Pulmonary Artery Thermodilution Research Articles

Evaluating haemodynamic changes: vericiguat in patients with heart failure with reduced ejection fraction.

Vericiguat has been used to treat patients with heart failure with reduced ejection fraction (HFrEF) who demonstrated worsening heart failure despite treatment with other guideline-directed medical therapies. The haemodynamic effects of vericiguat remain unclear. This study enrolled 12 patients (median age, 63 [quartiles 53.5, 70] years; 16.7%(N=2) women) with symptomatic HFrEF (New York Heart Association functional class II-IV) who demonstrated worsening heart failure despite treatment with the four foundational guideline-recommended therapies between March and December 2022, with follow-ups completed in June 2023. A balloon-tipped pulmonary artery thermodilution catheter was placed in the right internal jugular vein to perform right heart catheterisation (RHC) on day 1. Haemodynamic data were acquired before and after vericiguat intake (2.5mg) on days 2 and 3. The data on days 2 and 3 were averaged. RHC was repeated on day 105 (37, 168). Oral intake of vericiguat 2.5mg decreased mean pulmonary artery pressure (19.3 [14.3, 26.8] mmHg) and pulmonary artery wedge pressure (PAWP) (11 [7.5, 15] mmHg) before the intake to mean pulmonary artery pressure (17.5 [12.5, 24] mmHg) and PAWP (9.3 [6.8, 14] mmHg) at 30min after (both P<0.05). Reduction in PAWP was also found from 14.5 [9.5, 19.5] mmHg on day 1 to 9.5 [6.5, 12.5] mmHg on day 105 (37, 168) (P<0.05), when vericiguat was titrated to 2.5mg 25% (N=3), 5mg 50% (N=6), and 10mg 25% (N=3). The consistent reduction in PAWP underscores the well-tolerated nature of vericiguat and its potential to enhance cardiac performance in patients with HFrEF.

Performance of four cardiac output monitoring techniques vs. intermittent pulmonary artery thermodilution during a modified passive leg raise maneuver in isoflurane-anesthetized dogs.

This study investigated the performance among four cardiac output (CO) monitoring techniques in comparison with the reference method intermittent pulmonary artery thermodilution (iPATD) and their ability to diagnose fluid responsiveness (FR) during a modified passive leg raise (PLRM) maneuver in isoflurane-anesthetized dogs undergoing acute blood volume manipulations. The study also examined the simultaneous effect of performing the PLRM on dynamic variables such as stroke distance variation (SDV), peak velocity variation (PVV), and stroke volume variation (SVV). Prospective, nonrandomized, crossover design. Six healthy male Beagle dogs. The dogs were anesthetized with propofol and isoflurane and mechanically ventilated under neuromuscular blockade. After instrumentation, they underwent a series of sequential, nonrandomized steps: Step 1: baseline data collection; Step 2: removal of 33 mL kg-1 of circulating blood volume; Step 3: blood re-transfusion; and Step 4: infusion of 20 mL kg-1 colloid solution. Following a 10-min stabilization period after each step, CO measurements were recorded using esophageal Doppler (EDCO), transesophageal echocardiography (TEECO), arterial pressure waveform analysis (APWACO), and electrical cardiometry (ECCO). Additionally, SDV, PVV, and SVV were recorded. Intermittent pulmonary artery thermodilution (iPATDCO) measurements were also recorded before, during, and after the PLRM maneuver. A successful FR diagnosis made using a specific test indicated that CO increased by more than 15% during the PLRM maneuver. Statistical analysis was performed using one-way analysis of variance for repeated measures with post hoc Tukey test, linear regression, Lin's concordance correlation coefficient (ρc), and Bland-Altman analysis. Statistical significance was set at p < 0.05. All techniques detected a reduction in CO (p < 0.001) during hemorrhage and an increase in CO after blood re-transfusion and colloid infusion (p < 0.001) compared with baseline. During hemorrhage, CO increases with the PLRM maneuver were as follows: 33% for iPATD (p < 0.001), 19% for EC (p = 0.03), 7% for APWA (p = 0.97), 39% for TEE (p < 0.001), and 17% for ED (p = 0.02). Concurrently, decreases in SVV, SDV, and PVV values (p < 0.001) were also observed. The percentage error for TEE, ED, and EC was less than 30% but exceeded 55% for APWA. While TEECO and ECCO slightly underestimated iPATDCO values, EDCO and APWACO significantly overestimated iPATDCO values. TEE and EC exhibited good and acceptable agreement with iPATD. However, CO measurements using all four techniques and iPATD did not differ before, during, and after PLRM at baseline, blood re-transfusion, and colloid infusion. iPATD, EC, TEE, and ED effectively assessed FR in hypovolemic dogs during the PLRM maneuver, while the performance of APWA was unacceptable and not recommended. SVV, SDV, and PVV could be used to monitor CO changes during PLRM and acute blood volume manipulations, suggesting their potential clinical utility.

Agreement of cardiac output measurements by esophageal Doppler and transesophageal echocardiography with intermittent pulmonary artery thermodilution during pharmacologic manipulation of hemodynamics in anesthetized dogs.

To compare cardiac output (CO) measurements by transesophageal echocardiography (TEECO) and esophageal Doppler monitor (EDMCO) with pulmonary artery thermodilution (PATDCO) in anesthetized dogs subjected to pharmacological interventions. The effect of treatments on EDM-derived indexes was also investigated. 6 healthy male dogs (10.8 ± 0.7 kg). Dogs were anesthetized with propofol and isoflurane, mechanically ventilated, and monitored with invasive mean arterial pressure (MAP), end-tidal isoflurane concentration (ETISO), PATDCO, TEECO, EDMCO, and EDM-derived indexes. Four treatments were administered to all dogs by randomization. Baseline data were collected before each treatment: (1) dobutamine infusion; (2) esmolol infusion; (3) phenylephrine infusion; and (4) ETISO > 3%. Data were collected after 10-minute stabilization and after 30 minutes of washout between treatments. Statistical tests were pairwise t test, Bland-Altman analysis, Lin's concordance correlation (ρc), and polar plot analysis with P < .05 set as significance. The mean ± SD relative bias (limits of agreement) for TEECO was 0.35 ± 25.2% (-49.1% to 49.8%) and for EDMCO was -27.2 ± 22.5% (-71.4% to 17%) versus PATDCO. The percent error for TEECO and EDMCO was 27.6% and 44.1%, respectively. The ρc value was 0.82 for TEECO and 0.66 for EDMCO. TEECO and EDMCO showed good trending ability. EDM-derived indexes displayed significant changes specific to the drug administered (P < .001). For minimally invasive CO monitoring, TEE may provide more favorable performance than EDM in clinical settings; however, EDM-derived indexes yield valuable hemodynamic information that reliably follows trends in CO, thus supporting critical decision-making in canine patients.

Agreement between Electrical Cardiometry and Pulmonary Artery Thermodilution for Measuring Cardiac Output in Isoflurane-Anesthetized Dogs.

In animals, invasive pulmonary artery thermodilution (PATD) is a gold standard for cardiac output (CO) monitoring, but it is impractical in clinical settings. This study evaluates the agreement between PATD and noninvasive electrical cardiometry (EC) for measuring CO and analyzes the other EC-derived hemodynamic variables in six healthy anesthetized dogs subjected to four different hemodynamic events in a sequential order: (1) euvolemia (baseline); (2) hemorrhage (33% blood volume loss); (3) autologous blood transfusion; and (4) 20 mL/kg colloid bolus. The CO measurements obtained using PATD and EC are compared using Bland-Altman analysis, Lin's concordance correlation (LCC), and polar plot analysis. Values of p < 0.05 are considered significant. The EC measurements consistently underpredict the CO values as compared with PATD, and the LCC is 0.65. The EC's performance is better during hemorrhage, thus indicating its capability in detecting absolute hypovolemia in clinical settings. Even though the percentage error exhibited by EC is 49.4%, which is higher than the standard (<30%), EC displays a good trending ability. Additionally, the EC-derived variables display a significant correlation with the CO measured using PATD. Noninvasive EC may have a potential in monitoring trends in hemodynamics in clinical settings.

Volumetric evaluation of fluid responsiveness using a modified passive leg raise maneuver during experimental induction and correction of hypovolemia in anesthetized dogs

ObjectiveTo demonstrate if modified passive leg raise (PLRM) maneuver can be used for volumetric evaluation of fluid responsiveness (FR) by inducing cardiac output (CO) changes during experimental induction and correction of hypovolemia in healthy anesthetized dogs. The effects of PLRM on plethysmographic variability index (PVI) and pulse pressure variation (PPV) were also investigated. Study designProspective, crossover study. AnimalsA total of six healthy anesthetized Beagle dogs. MethodsDogs were anesthetized with propofol and isoflurane. They were mechanically ventilated under neuromuscular blockade, and normothermia was maintained. After instrumentation, all dogs were subjected to four stages: 1, baseline; 2, removal of 27 mL kg–1 circulating blood volume; 3, after blood re-transfusion; and 4, after 20 mL kg–1 hetastarch infusion over 20 minutes. A 10 minute stabilization period was allowed after induction of each stage and before data collection. At each stage, CO via pulmonary artery thermodilution, PVI, PPV and cardiopulmonary variables were measured before, during and after the PLRM maneuver. Stages were sequential, not randomized. Statistical analysis included repeated measures anova and Tukey’s post hoc test, considering p < 0.05 as significant. ResultsDuring stage 2, PLRM at a 30° angle significantly increased CO (mean ± standard deviation, 1.0 ± 0.1 to 1.3 ± 0.1 L minute–1; p < 0.001), with a simultaneous significant reduction in PVI (38 ± 4% to 21 ± 4%; p < 0.001) and PPV (27 ± 2% to 18 ± 2%; p < 0.001). The PLRM did not affect CO, PPV and PVI during stages 1, 3 and 4. Conclusions and clinical relevanceIn anesthetized dogs, PLRM at a 30° angle successfully detected FR during hypovolemia, and identified fluid nonresponsiveness during normovolemia and hypervolemia. Also, in hypovolemic dogs, significant decreases in PVI and PPV occurred in response to PLRM maneuver.

Esophageal Doppler-derived indices and arterial load variables provide useful hemodynamic information during assessment of fluid responsiveness in anesthetized dogs undergoing acute changes in blood volume.

To investigate the relationship between invasively measured stroke volume (SV) and (1) esophageal Doppler-derived indices such as stroke distance (StrokeD), flow time corrected (FTc), stroke distance variation (SDV), and peak velocity variation (PVV); and (2) arterial load (AL) variables during evaluation of fluid responsiveness (FR) in anesthetized dogs undergoing sudden hemodynamic shifts in blood volume. 6 healthy male dogs. Dogs were anesthetized with isoflurane, ventilated mechanically, and instrumented to undergo sequential, nonrandomized experimental stages. The dogs transitioned from normovolemia (NORMO-BL) to hypovolemia (30% blood loss; HYPO-30), followed by autologous blood transfusion, and then to hypervolemia (colloid bolus). During each stage, SV was quantified using pulmonary artery thermodilution and its relationship with StrokeD, FTc, SDV, and PVV; and AL variables such as effective arterial elastance (Ea), dynamic arterial elastance (Eadyn), and total arterial compliance (Ca) were established. As SV decreased significantly during HYPO-30 compared to NORMO-BL, there was a significant (P < .001) decrease in StrokeD, FTc, and Ca, with simultaneous increases in SDV, PVV, Ea, and Eadyn. Upon restoration of blood volume, these values stabilized closer to NORMO-BL. A significant (P < .001) correlation was observed between SV and StrokeD, FTc, Ea, Eadyn, and Ca. Minimally invasive StrokeD, FTc, SDV, and PVV act as SV surrogates and help assess FR during different blood volume stages in healthy dogs. During hypovolemia-induced hypotension, Ea, Eadyn, and Ca may be able to guide therapeutic decisions favoring improvement in blood pressure and SV.

Evaluation of four cardiac output measurement techniques during a modified passive leg raise maneuver in anesthetized dogs

Introduction: Modified passive leg raise maneuver (PLRM) is a successful volumetric predictor of fluid responsiveness in dogs during experimental induction and correction of hypovolemia using invasive pulmonary artery thermodilution (PACTD) for measuring cardiac output (CO). In this study, other CO methods, minimally-invasive esophageal Doppler (ESD), transesophageal echocardiography (TEE), arterial pressure waveform analysis (APW), noninvasive electrical velocimetry (EV), were investigated during PLRM in anesthetized dogs.

Cardiac output monitoring with pulmonary versus trans-cardiopulmonary thermodilution in left ventricular assist devices: Interchangeable methods?

Cardiac output (CO) measurement is mandatory in patients with left ventricular assist devices (LVADs). Thermodilution with pulmonary artery catheter (PAC) remains the clinical gold standard to measure CO in these patients, however it is associated with several complications. Therefore, the agreement between PAC and new, minimally invasive monitoring methods in LVAD needs to be further investigated. The aim of this study was to assess the accuracy and reliability of transpulmonary thermodilution with a PiCCO2 monitor compared with pulmonary artery thermodilution with PAC in a LVAD. Continuous-flow LVADs were implanted in six mini-pigs to assist the left ventricle. We studied two methods of measuring CO—intermittent transpulmonary thermodilution (COTPTD) by PiCCO2 and intermittent pulmonary artery thermodilution by CAP, standard technique (COPTD)—obtained in four consecutive moments of the study: before starting the LVAD (basal moment), and with the LVAD started in normovolemia, hypervolemia (fluid overloading) and hypovolemia (shock hemorrhage). A total of 72 paired measurements were analysed. At the basal moment, COTPTD and COPTD were closely correlated (r 2 = 0.89), with a mean bias of −0.085 ± 0.245 L/min and percentage error of 16%. After 15 min of partial support LVAD, COTPTD and COPTD were closely correlated (r 2 = 0.79), with a mean bias of −0.040 ± 0.417 L/min and percentage error of 26%. After inducing hypervolemia, COTPTD and COPTD were closely correlated (r 2 = 0.78), with a mean bias of −0.093 ± 0.339 L/min and percentage error of 13%. After inducing hypovolemia, COTPTD and COPTD were closely correlated (r 2 = 0.76), with a mean bias of −0.045 ± 0.281 L/min and percentage error of 28%. This study demonstrates a good agreement between transpulmonary thermodilution by PiCCO monitor and pulmonary thermodilution by PAC in the intermittent measurement of CO in a porcine model with a continuous-flow LVAD.

A new noninvasive finger sensor (NICCI system) for cardiac output monitoring: A method comparison study in patients after cardiac surgery.

The new noninvasive finger sensor system NICCI (Getinge; Gothenburg, Sweden) allows continuous cardiac output monitoring. We aimed to investigate its cardiac output measurement performance. To investigate the NICCI system's cardiac output measurement performance. Prospective method comparison study. University Medical Center Hamburg-Eppendorf, Hamburg, Germany. Fifty-one patients after cardiac surgery. We performed a method comparison study in 51 patients after cardiac surgery to compare NICCI cardiac output (CO NICCI ) and NICCI cardiac output calibrated to pulmonary artery thermodilution cardiac output measurement (CO NICCI-CAL ) with pulmonary artery thermodilution cardiac output (CO PAT ). As a secondary analysis we also compared CNAP cardiac output (CO CNAP ) and externally calibrated CNAP cardiac output (CO CNAP-CAL ) with CO PAT . We analysed 299 cardiac output measurement pairs. The mean of the differences (95% limits of agreement) between CO NICCI and CO PAT was 0.6 (-1.8 to 3.1) l min -1 with a percentage error of 48%. The mean of the differences between CO NICCI-CAL and CO PAT was -0.4 (-1.9 to 1.1) l min -1 with a percentage error of 29%. The mean of the differences between CO CNAP and CO PAT was 1.0 (-1.8 to 3.8) l min -1 with a percentage error of 53%. The mean of the differences between CO CNAP-CAL and CO PAT was -0.2 (-2.0 to 1.6) l min -1 with a percentage error of 35%. The agreement between CO NICCI and CO PAT is not clinically acceptable. The study was registered in the German Clinical Trial Register (DRKS00023189) after inclusion of the first patient on October 2, 2020.

Transpulmonary ultrasound dilution is an acceptable technique for cardiac output measurement in anesthetized pigs

To evaluate cardiac output (CO) measurements using transpulmonary ultrasound (TPUD) technology and compare results with those of the gold standard, pulmonary arterial catheter thermodilution (PACTD), in 6 healthy anesthetized pigs during acute hemodynamic changes caused by manipulation of the blood volume. 6 healthy male Landrace pigs. Over a period of 1 week, pigs were anesthetized with isoflurane, mechanically ventilated, and underwent instrumentation in dorsal recumbency. They were subjected to sequential experimental states during which the blood volume was manipulated so that the animals transitioned from normovolemia to hypovolemia (20% and 40% of blood volume depletion), back to normovolemia (autologous blood transfusion), and then to hypervolemia (following colloid bolus). During each volume state, CO measurements were compared between TPUD and PACTD. The mean ± SD relative bias between TPUD and PACTD was 7.71% ± 21.2% with limits of agreement -33.9% to 49.3%, indicating TPUD slightly underestimated CO values, compared with values obtained with PACTD. The mean ± SD of the bias between the 2 methods was 0.13 ± 0.5 L/min. Only 5 of 36 (13.9%) TPUD CO measurements had an absolute value of relative bias > 30%. The percentage error calculated for TPUD was 29.4%. Results suggested that TPUD measurements have acceptable agreement with PACTD measurements. Moreover, TPUD exhibits promising potential in being used interchangeably with PACTD for future hemodynamic research involving swine as species of interest.

Perioperative Hemodynamic Monitoring: An Overview of Current Methods.

Perioperative hemodynamic monitoring is an essential part of anesthetic care. In this review, we aim to give an overview of methods currently used in the clinical routine and experimental methods under development. The technical aspects of the mentioned methods are discussed briefly. This review includes methods to monitor blood pressures, for example, arterial pressure, mean systemic filling pressure and central venous pressure, and volumes, for example, global end-diastolic volume (GEDV) and extravascular lung water. In addition, monitoring blood flow (cardiac output) and fluid responsiveness (preload) will be discussed.

Evaluation of the ability of haemodynamic variables obtained with minimally invasive techniques to assess fluid responsiveness in endotoxaemic Beagles

ObjectiveTo examine the ability of different haemodynamic variables recorded by minimally invasive monitoring techniques to assess fluid responsiveness (FR) in endotoxaemic Beagles. Study designProspective terminal experimental study. AnimalsA group of six healthy, purpose-bred Beagle dogs (three intact females and males), age 5–9.8 years (range) and weighing 11.4–17.9 kg. MethodsEndotoxaemic shock was induced by injecting 1 mg kg–1Escherichia coli lipopolysaccharide (LPS) intravenously in six sevoflurane-anaesthetized mechanically ventilated Beagles for another project. After 10 minutes, three Ringer’s acetate boluses (10 mL kg–1) were administered each over 10 minutes with collection of haemodynamic data immediately before and after each bolus. Thereafter, arterial hypotension was treated with noradrenaline ± dexmedetomidine until arterial pressures increased to a target value. After a wash-out period of 20 minutes another three boluses of fluid were administered and measurements were repeated equally. For each fluid bolus, FR was considered positive when change (Δ) in stroke volume measured by pulmonary artery thermodilution was ≥15%. To test predictive accuracy for FR, we recorded heart rate, invasive arterial, right atrial and pulmonary capillary wedge pressures, pulse wave transit time with haemodynamic monitors, calculated pulse pressure, shock index and rate over pressure evaluation (ROPE) and measured stroke distance and corrected flow time (FTc) with oesophageal Doppler monitoring. ResultsA total of 35 measurements (19 positive and 16 negative responses) were evaluated. A FTc < 330 ms, Δ pulse pressure ≥20%, Δ shock index ≤–14% and ΔROPE ≤–17% were the most significant indicators of positive FR with an area under the receiver operating characteristics curve between 0.72 and 0.74. Conclusions and clinical relevanceIn endotoxaemic Beagles, none of the assessed haemodynamic variables could predict FR with high sensitivity and specificity.

Agreement between continuous and intermittent pulmonary artery thermodilution for cardiac output measurement in perioperative and intensive care medicine: a systematic review and meta-analysis

BackgroundPulmonary artery thermodilution is the clinical reference method for cardiac output monitoring. Because both continuous and intermittent pulmonary artery thermodilution are used in clinical practice it is important to know whether cardiac output measurements by the two methods are clinically interchangeable.MethodsWe performed a systematic review and meta-analysis of clinical studies comparing cardiac output measurements assessed using continuous and intermittent pulmonary artery thermodilution in adult surgical and critically ill patients. 54 studies with 1522 patients were included in the analysis.ResultsThe heterogeneity across the studies was high. The overall random effects model-derived pooled estimate of the mean of the differences was 0.08 (95%-confidence interval 0.01 to 0.16) L/min with pooled 95%-limits of agreement of − 1.68 to 1.85 L/min and a pooled percentage error of 29.7 (95%-confidence interval 20.5 to 38.9)%.ConclusionThe heterogeneity across clinical studies comparing continuous and intermittent pulmonary artery thermodilution in adult surgical and critically ill patients is high. The overall trueness/accuracy of continuous pulmonary artery thermodilution in comparison with intermittent pulmonary artery thermodilution is good (indicated by a pooled mean of the differences < 0.1 L/min). Pooled 95%-limits of agreement of − 1.68 to 1.85 L/min and a pooled percentage error of 29.7% suggest that continuous pulmonary artery thermodilution barely passes interchangeability criteria with intermittent pulmonary artery thermodilution.PROSPERO registration number CRD42020159730.

New Advances in Monitoring Cardiac Output in Circulatory Mechanical Assistance Devices. A Validation Study in a Porcine Model.

Cardiac output (CO) measurement by continuous pulmonary artery thermodilution (COCTD) has been studied in patients with pulsatile-flow LVADs (left ventricular assist devices), confirming the clinical utility. However, it has not been validated in patients with continuous-flow LVADs. Therefore, the aim of this study was to assess the validity of COCTD in continuous-flow LVADs. Continuous-flow LVADs were implanted in six miniature pigs for partial assistance of the left ventricle. Both methods of measuring CO—measurement by COCTD and intermittent pulmonary artery thermodilution, standard technique (COITD)—were used in four consecutive moments of the study: before starting the LVAD (basal moment), and with the LVAD started in normovolemia, hypervolemia (fluid overloading), and hypovolemia (shock hemorrhage). At the basal moment, COCTD and COITD were closely correlated (r2 = 0.97), with a mean bias of −0.13 ± 0.16 L/min and percentage error of 11%. After 15 min of partial support LVAD, COCTD and COITD were closely correlated (r2 = 0.91), with a mean bias of 0.31 ± 0.35 L/min and percentage error of 20%. After inducing hypervolemia, COCTD and COITD were closely correlated (r2 = 0.99), with a mean bias of 0.04 ± 0.07 L/min and percentage error of 5%. After inducing hypovolemia, COCTD and COITD were closely correlated (r2 = 0.74), with a mean bias of 0.08 ± 0.22 L/min and percentage error of 19%. This study shows that continuous pulmonary thermodilution could be an alternative method of monitoring CO in a porcine model with a continuous-flow LVAD.

Reliability of Pulse Contour Cardiac Output Analysis in a Piglet Model of Multi-step Intra-abdominal Hypertension

BackgroundPulse contour cardiac output (PCCO) analysis is a minimally invasive technique for continuous cardiac output (CO) measurement monitoring. PCCO requires calibration by transpulmonary thermodilution (TPTD). Studies showed good agreement between PCCO, TPTD CO and CO measured by pulmonary artery thermodilution (PATD) during stable hemodynamics. However, data are limited in patients with intra-abdominal hypertension (IAH). The objective is to compare the agreement between PCCO, TPTD CO, and PATD CO in a piglet model of multi-step IAH. Materials and methodsTen female domestic piglets were enrolled in this study. IAH was induced by stepwise carbon dioxide inflation into peritoneal cavity in anesthetized piglets. Following baseline registrations, intra-abdominal pressure (IAP) was increased and maintained at each IAP plateau of 10, 20, 30, and 40 mmHg for 15 min before CO measurements. CO was measured by PATD and simultaneously by 2 femoral artery PCCO catheters. One PCCO catheter was recalibrated by TPTD at each IAP plateau while the other was only calibrated at baseline. ResultsIn pooled data of different IAP stages, TPTD CO and recalibrated PCCO (R-PCCO) showed excellent correlation (r2 = 0.94 and 0.93) and small bias (−0.09 and −0.09 L/min), respectively, compared with PATD CO. However, PCCO without recalibration (NR-PCCO) were not accurate during IAH (r2 = 0.58, bias: +0.32 L/min). When IAP increased to 30 mmHg, NR-PCCO failed to agree with PATD CO (r2 = 0.47, bias: +0.52 L/min). On the contrary, a clinically accepted agreement between TPTD CO, R-PCCO, and PATD CO was observed at different IAP stages. ConclusionsTPTD CO and R-PCCO agreed with PATD CO in this piglet model of multi-step IAH. On the contrary, NR-PCCO failed to agree with PATD CO when IAP increased to 30 mmHg or more. PCCO analysis needs recalibration in this condition.

Cardiac output estimation by pulse wave analysis using the pressure recording analytical method and intermittent pulmonary artery thermodilution: A method comparison study after off-pump coronary artery bypass surgery.

Invasive pulse wave analysis is used in peri-operative settings to estimate cardiac output (CO). The 'pressure recording analytical method' (PRAM) implemented in the MostCareUp CO monitor is an invasive pulse wave analysis method using high-frequency sampling and analysis of the pulse wave to directly estimate the arterial impedance as a key variable of the proprietary CO estimation algorithm. To compare CO estimated by PRAM (PRAM-CO; test method) with CO measured by pulmonary artery thermodilution (PATD-CO; reference method). Prospective observational method comparison study. PRAM-CO and PATD-CO were assessed simultaneously at five time points with at least 20 min between measurements. Arterial pressure waveforms were carefully checked for damping artefacts and a proprietary electronic filter of the MostCareUp CO monitor was used to optimise waveform quality. ICU of a German university hospital from August 2018 until April 2019. We included adult patients admitted to the ICU after elective off-pump coronary artery bypass surgery who were monitored with a radial arterial catheter and a pulmonary artery catheter. Patients with severe heart valve insufficiency or persistent arrhythmia were excluded. PATD-CO and PRAM-CO were compared using Bland-Altman analysis accounting for repeated measurements, the percentage error and trending analysis (four-quadrant plot, concordance rate). We analysed 195 paired CO values of 41 patients. Mean PATD-CO and PRAM-CO were 4.99 ± 1.02 and 4.92 ± 1.05 l min, respectively. PATD-CO and PRAM-CO ranged from 3.04 to 8.74 and 2.79 to 8.01 l min, respectively. The mean of the differences between PATD-CO and PRAM-CO was -0.08 ± 0.74 l min with 95% limits of agreement of -1.55 to +1.40 l min. The percentage error was 29.8%. The concordance rate in four-quadrant plot analysis was 92%. Using the system's electronic waveform filter PRAM-CO shows good agreement and trending ability compared with PATD-CO in adults after off-pump coronary artery bypass surgery.

New noninvasive methodology to measure cardiac output in veno-venous extracorporeal membrane oxygenation patients.

Cardiac output (CO) measurement is vital in veno-venous extracorporeal membrane oxygenation patient population to evaluate oxygen delivery and to early identify right heart failure. Standard clinical methods like pulmonary artery thermodilution and transpulmonary thermodilution are known to be inaccurate in the veno-venous extracorporeal membrane oxygenation setting, especially at high levels of recirculation. The aim of the study was to develop a simple noninvasive method to measure CO in patients during veno-venous extracorporeal membrane oxygenation. A mathematical model was developed where CO was analyzed as a combination of two flows: oxygenated blood from extracorporeal membrane oxygenation and less oxygenated mixed venous blood. The system of two mass balance equations for oxygen saturations was introduced to calculate CO. The procedure included measurement of recirculation (ELSA Monitor Transonic Systems Inc. Ithaca, USA) and arterial saturation at two extracorporeal membrane oxygenation flows after temporary pump flow decrease. Mathematic modeling that utilized a crude Monte Carlo method was used to analyze theoretical errors in CO calculations from unknown behavior of venous saturation. The developed concept was retrospectively applied to clinical data archive of 17 adult patients on veno-venous extracorporeal membrane oxygenation that included 52 measurement sessions. Mathematical modeling suggests that proportion of results with error ⩽10% was between 86% and 100% if pre-oxygenated saturation was available and it was between 78% and 86% if pre-oxygenated saturation was not available. Application of two mass balance equation concept to clinical data suggests that as the decrease of the arterial saturation reaches 6% due to flow decrease, then CO calculations becomes highly reliable as 96% (2 standard deviations) of the results has a reproducibility within 6.4%. The mathematical model and clinical retrospective analysis demonstrates that the new methodology has the potential to accurately measure CO in veno-venous extracorporeal membrane oxygenation patients. The next step is validation in animal and clinical settings.

Transpulmonary thermodilution before and during veno-venous extra-corporeal membrane oxygenation ECMO: an observational study on a potential loss of indicator into the extra-corporeal circuit.

Haemodynamic monitoring before extra-corporeal membrane oxygenation (ECMO) might help to optimize the effectiveness of ECMO. However, there are concerns that pulmonary arterial and trans-pulmonary thermodilution (TPTD) might be confounded by a loss of indicator into the ECMO-circuit, resulting in an overestimation of volumetric parameters. Since there is a lack of data on indicator dilution techniques during ECMO, we compared TPTD-measurements before and during ECMO. TPTD-derived parameters before and after initiation of ECMO were compared in 14 intensive care unit-patients with veno-venous ECMO and TPTD-monitoring (PiCCO®). Eight patients had a jugular and six patients a femoral central venous catheter (CVC). Cardiac index, global end-diastolic volume index (GEDVI) and extra-vascular lung water index (EVLWI) before ECMO as well as the ECMO-flow were comparable in patients with jugular and femoral CVC. Pre-ECMO, cardiac index (CI) was not significantly different compared to values during ECMO (4.5 ± 1.7 vs. 4.4 ± 2.1 L/min/m2; p = 0.43). By contrast, GEDVI (791 ± 179 vs. 974 ± 384mL/m2; p = 0.04) and EVLWI (21 ± 9 vs. 28 ± 11mL/kg; p < 0.01) were higher during ECMO than before. Increases in GEDVI (36 ± 210 vs. 378 ± 247mL/m2; p = 0.02) and EVLWI (3 ± 2 vs. 11 ± 8mL/kg; p = 0.06) were substantially more pronounced in patients with femoral compared to jugular indicator injection. In multivariate analysis, femoral indicator injection was independently associated with larger increases in GEDVI (p < 0.01) and EVLWI (p = 0.04) during ECMO. However, CI and haemodynamic parameters not derived from TPTD, but from pulse contour analysis (systolic and diastolic arterial pressure, stroke volume variation and pulse pressure variation) were not affected by the start of ECMO. Our study demonstrates marked increases in GEDVI and EVLWI after the onset of ECMO. These increases were more pronounced for femoral compared to jugular indicator injection. CI and haemodynamic parameters not derived from TPTD were not affected by the extra-corporeal circuit.

Levosimendan or milrinone for right ventricular inotropic treatment?-A secondary analysis of a randomized trial.

The aim of the present study was to compare the effects of milrinone and levosimendan on right ventricular (RV) inotropy and lusitropy in patients after aortic valve replacement (AVR) for aortic stenosis, a procedure in which an abnormal postoperative RV function may be seen. In a prospective, blinded trial, 31 patients were randomized to receive either milrinone (0.4 and 0.8µg/kg/min, n=16) or levosimendan (0.1 and 0.2µg/kg/min, n=15) after AVR for aortic stenosis. RV performance, afterload (pulmonary arterial elastance), RV strain, systolic (SR-S) and early diastolic (SR-E) strain rate were measured by pulmonary artery thermodilution catheterization and transoesophageal two-dimensional speckle tracking echocardiography. To circumvent the indirect effects of inodilator-induced hemodynamic changes on RV systolic and diastolic deformation, pulmonary arterial elastance, central venous pressure and heart rate were maintained constant by atrial pacing, plasma volume expansion with colloids and phenylephrine-induced vasoconstriction during treatment with the inotropes. A dose-dependent increase in stroke volume index and cardiac index by approximately 20% were seen with both agents at the highest doses, with no difference between groups (P=.792 and 0.744, respectively). In both groups, RV strain and SR-S dose-dependently increased by 20% and 15%-19%, respectively, at the highest doses (P=.742 and 0.259, respectively) with no difference between groups. SR-E improved by both agents 20%-24% at the highest dose with no difference between groups (P=.714). The direct RV inotropic and lusitropic effects of levosimendan and milrinone were comparable at clinically relevant infusion rates.

Cardiac Effects of Hyperoxia During Resuscitation From Hemorrhagic Shock in Swine.

Hyperoxia (ventilation with FIO2 = 1.0) has vasoconstrictor properties, in particular in the coronary vascular bed, and, hence, may promote cardiac dysfunction. However, we previously showed that hyperoxia attenuated myocardial injury during resuscitation from hemorrhage in swine with coronary artery disease. Therefore, we tested the hypothesis whether hyperoxia would also mitigate myocardial injury and improve heart function in the absence of chronic cardiovascular comorbidity.After 3 h of hemorrhage (removal of 30% of the calculated blood volume and subsequent titration of mean arterial pressure to 40 mm Hg) 19 anesthetized, mechanically ventilated, and instrumented pigs received FIO2 = 0.3(control) or hyperoxia(FIO2 = 1.0) during the first 24 h. Before, at the end of and every 12 h after shock, hemodynamics, blood gases, metabolism, cytokines, and cardiac function (pulmonary artery thermodilution, left ventricular pressure-conductance catheterization) were recorded. At 48 h, cardiac tissue was harvested for western blotting, immunohistochemistry, and mitochondrial respiration.Except for higher left ventricular end-diastolic pressures at 24 h (hyperoxia 21 (17;24), control 17 (15;18) mm Hg; P = 0.046), hyperoxia affected neither left ventricular function cardiac injury (max. Troponin I at 12 h: hyperoxia:9 (6;23), control:17 (11;24) ng mL; P = 0.395), nor plasma cytokines (except for interleukin-1β: hyperoxia 10 (10;10) and 10 (10;10)/control 14 (10;22), 12 (10;15) pg mL, P = 0.023 and 0.021 at 12 and 24 h, respectively), oxidation and nitrosative stress, and mitochondrial respiration. However, hyperoxia decreased cardiac tissue three-nitrotyrosine formation (P < 0.001) and inducible nitric oxide synthase expression (P = 0.016). Ultimately, survival did not differ significantly either.In conclusion, in contrast to our previous study in swine with coronary artery disease, hyperoxia did not beneficially affect cardiac function or tissue injury in healthy swine, but was devoid of deleterious side effects.