Transpulmonary Thermodilution Measurements Research Articles

Injection Site Matters: A Comparative Analysis of Transpulmonary Thermodilution via Simultaneous Femoral and Jugular Indicator Injections under Veno-Venous Extracorporeal Membrane Oxygenation Therapy.

Background: The use of veno-venous extracorporeal membrane oxygenation (vv-ECMO) in acute lung failure has witnessed a notable increase. The PiCCO system is frequently used for advanced hemodynamic monitoring in this cohort. Our study aimed to investigate whether the choice of indicator injection site (jugular vs. femoral) in patients undergoing vv-ECMO therapy affects transpulmonary thermodilution (TPTD) measurements using the PiCCO® device (Pulsion Medical Systems SE, Munich, Germany). Methods: In a retrospective single-center analysis, we compared thermodilution-derived hemodynamic parameters after simultaneous jugular and femoral injections in 28 measurements obtained in two patients with respiratory failure who were undergoing vv-ECMO therapy. Results: Elevated values of the extravascular lung water index (EVLWI), intrathoracic blood volume index (ITBVI) and global end-diastolic volume index (GEDVI) were observed following femoral indicator injection compared to jugular indicator injection (EVLWI: 29.3 ± 10.9 mL/kg vs. 18.3 ± 6.71 mL/kg, p = 0.0003; ITBVI: 2163 ± 631 mL/m2 vs. 806 ± 125 mL/m2, p < 0.0001; GEDVI: 1731 ± 505 mL/m2 vs. 687 ± 141 mL/m2, p < 0.0001). The discrepancy between femoral and jugular measurements exhibited a linear correlation with extracorporeal blood flow (ECBF). Conclusions: In a PiCCO®-derived hemodynamic assessment of patients on vv-ECMO, the femoral indicator injection, as opposed to the jugular injection, resulted in an overestimation of all index parameters. This discrepancy can be attributed to mean transit time (MTt) and downslope time-dependent (DSt) variations in GEDVI and cardiac function index and is correlated with ECBF.

A deep learning model enables accurate prediction and quantification of pulmonary edema from chest X-rays

BackgroundA quantitative assessment of pulmonary edema is important because the clinical severity can range from mild impairment to life threatening. A quantitative surrogate measure, although invasive, for pulmonary edema is the extravascular lung water index (EVLWI) extracted from the transpulmonary thermodilution (TPTD). Severity of edema from chest X-rays, to date is based on the subjective classification of radiologists. In this work, we use machine learning to quantitatively predict the severity of pulmonary edema from chest radiography.MethodsWe retrospectively included 471 X-rays from 431 patients who underwent chest radiography and TPTD measurement within 24 h at our intensive care unit. The EVLWI extracted from the TPTD was used as a quantitative measure for pulmonary edema. We used a deep learning approach and binned the data into two, three, four and five classes increasing the resolution of the EVLWI prediction from the X-rays.ResultsThe accuracy, area under the receiver operating characteristic curve (AUROC) and Mathews correlation coefficient (MCC) in the binary classification models (EVLWI < 15, ≥ 15) were 0.93 (accuracy), 0.98 (AUROC) and 0.86(MCC). In the three multiclass models, the accuracy ranged between 0.90 and 0.95, the AUROC between 0.97 and 0.99 and the MCC between 0.86 and 0.92.ConclusionDeep learning can quantify pulmonary edema as measured by EVLWI with high accuracy.

Transpulmonary thermodilution: A revised correction formula for global end-diastolic volume index derived after femoral indicator injection.

Transpulmonary thermodilution (TPTD) is usually performed by jugular indicator injection. In clinical practice, femoral venous access is often used instead, resulting in substantial overestimation of global end-diastolic volume index (GEDVI). A correction formula compensates for that. The objective of this study is to first evaluate the efficacy of the currently implemented correction function and then further improve this formula. The performance of the established correction formula was investigated in our prospectively collected dataset of 98 TPTD measurements from 38 patients with both, jugular and femoral venous access. Subsequently, a new correction formula was developed: cross validation revealed the favourite covariate combination and a general estimating equation provided the final version, which was tested in a retrospective validation on an external dataset. Investigating the current correction function revealed a considerable reduction of bias compared to no correction. Concerning the objective of formula development, the covariate combination of GEDVI obtained after femoral indicator injection, age and body surface area is even favoured, when compared to the parameters of the previously published correction formula, as a further reduction of mean absolute error (68 vs. 61 ml/m2), a better correlation (0.90 vs. 0.91) and an increased adjusted R2 (0.72 vs 0.78) is noticed in the cross validation results. Of particular clinical importance is, that more measurements were correctly assigned to the same GEDVI category (decreased / normal / increased) using the revised formula, compared with the gold standard of jugular indicator injection (72.4 vs. 74.5%). In a retrospective validation, the newly developed formula showed a greater reduction of bias (to 2 vs. 6 %) than the currently implemented formula. The currently implemented correction function partly compensates for GEDVI overestimation. Applying the new correction formula on GEDVI measured after femoral indicator administration enhances the informative value and reliability of this preload parameter.

Diagnostic value of transpulmonary thermodilution measurements for acute respiratory distress syndrome in a pig model of septic shock

BackgroundNo direct approach assessing pulmonary vascular permeability exists in the current therapeutic strategy for patients with acute respiratory distress syndrome (ARDS). Transpulmonary thermodilution measures hemodynamic parameters such as pulmonary vascular permeability index and extravascular lung water, enabling clinicians to assess ARDS severity. The aim of this study is to explore a precise transpulmonary thermodilution-based criteria for quantifying the severity of lung injury using a clinically relevant septic-ARDS pig model.MethodsThirteen female pigs (weight: 31 ± 2 kg) were intubated, mechanically ventilated under anesthesia, and either assigned to septic shock-induced ARDS or control group. To confirm the development of ARDS, we performed computed tomography (CT) imaging in randomly selected animals. The pulmonary vascular permeability index, extravascular lung water, and other hemodynamic parameters were consecutively measured during the development of septic lung injury. Lung status was categorized as normal (partial pressure of oxygen/fraction of inspired oxygen ≥ 400), or injured at different degrees: pre-ARDS (300–400), mild-to-moderate ARDS (100–300), or severe ARDS (< 100). We also measured serum inflammatory cytokines and high mobility group box 1 levels during the experiment to explore the relationship of the pulmonary vascular permeability index with these inflammatory markers.ResultsUsing CT image, we verified that animals subjected to ARDS presented an extent of consolidation in bilateral gravitationally dependent gradient that expands over time, with diffuse ground-glass opacification. Further, the post-mortem histopathological analysis for lung tissue identified the key features of diffuse alveolar damage in all animals subjected to ARDS. Both pulmonary vascular permeability index and extravascular lung water increased significantly, according to disease severity. Receiver operating characteristic analysis demonstrated that a cut-off value of 3.9 for the permeability index provided optimal sensitivity and specificity for predicting severe ARDS (area under the curve: 0.99, 95% confidence interval, 0.98–1.00; sensitivity = 100%, and specificity = 92.5%). The pulmonary vascular permeability index was superior in its diagnostic value than extravascular lung water. Furthermore, the pulmonary vascular permeability index was significantly associated with multiple parameters reflecting clinicopathological changes in animals with ARDS.ConclusionThe pulmonary vascular permeability index is an effective indicator to measure septic ARDS severity.

The Association Between Extravascular Lung Water and Critical Care Outcomes Following Bilateral Lung Transplantation.

Background.Primary graft dysfunction (PGD) is a form of acute respiratory failure that complicates 30% of bilateral lung transplants. Higher grades of PGD correlate with higher severity of respiratory failure and unfavorable outcomes. Immediate PGD determination posttransplant‚ however, is not always predictive of PGD over subsequent days or intensive care unit outcomes. We aimed to evaluate whether extravascular lung water index (ELWI) measured immediately post bilateral lung transplant was associated with higher severity of PGD at 72 h and duration of mechanical ventilation.Methods.We conducted a prospective, observational study of bilateral lung transplant patients admitted to the intensive care unit. ELWI measurements were performed at admission, 6, 12, 24, 36, 48, 60, and 72 h following transplant or until extubation. We evaluated the association between admission ELWI and 72-h PGD grade and duration of mechanical ventilation.Results.Across 56 patients enrolled, 268 transpulmonary thermodilution measurements were conducted. At admission, median ELWI increased with PGD grade (grade 1: 9 mL/kg [interquartile range (IQR), 8–11 mL/kg]‚ grade 2 [10 mL/kg (IQR, 8–12 mL/kg)]‚ and grade 3 [17 mL/kg (IQR, 14–19 mL/kg); P < 0.001]). Using multivariable Poisson regression analysis adjusting for confounders, admission ELWI elevation was associated with higher severity of PGD at 72 h (incidence rate ratio [IRR], 1.06; 95% confidence interval, 1.01-1.12) and duration of mechanical ventilation (IRR, 1.62; 95% confidence interval, 1.23-2.14). The combination of an ELWI of ≥13 mL/kg and partial pressure of oxygen/fraction of inspired oxygen ≤ 100 within 6 h of admission had high sensitivity (75%) and specificity (100%) for grade 3 PGD at 72 h (area under the curve, 0.95) and performed better than ELWI or partial pressure of oxygen/fraction of inspired oxygen alone.Conclusions.Our exploratory study demonstrates an association between admission ELWI and high grades of PGD at 72 h and longer duration of ventilation. These results provide the impetus to study whether goal-directed ELWI algorithms can improve transplant outcomes.

Cardiac output monitoring using transthoracic echocardiography in children after cardiac surgery-an observational study of feasibility and concordance with transpulmonary thermodilution

Abstract Background Transthoracic echocardiography (TTE) is commonly used after pediatric cardiac surgery to monitor cardiac function and adequacy of surgery; however it depends on the availability of good echo window and operator skill [1]. Transpulmonary thermodilution (TPTD) is feasible along with calibrated continuous cardiac output measurement in children but seldom used due to cost and the need for a specialized catheter [2]. We hypothesized that TTE would be as good as TPTD, but limited in feasibility following pediatric cardiac surgery. Hence, the concordance, agreement as well as feasibility and trending of cardiac output monitoring by TTE was compared against a reference TPTD method in real-world usage in children after congenital heart surgery. Methods This was a secondary analysis of data from a previously registered and conducted study in our unit. TPTD monitoring was instituted in children undergoing congenital heart disease repair on cardiopulmonary bypass with a 3F femoral arterial cannula and a central venous injectate temperature sensor. Cardiac output was also measured by transthoracic echocardiography by measurement of the left ventricular outflow tract (LVOT) diameter, LVOT velocity time integral (VTI) and the heart rate as previously described [3,4]. Measurements were taken after arrival in the ICU, and every 12 hours till after extubation. Correlation, Bland-Altman analysis and polar analysis was done for cardiac output measured by TPTD and TTE. Results TTE and TPTD measurements of cardiac output correlated well (Pearson's correlation coefficient 0.94; 95% CI 0.90–0.96) (Fig. 1A). Bland Altman analysis showed a mean bias of 0.15 l/min and upper and lower limits of agreement of 0.81 and −0.51 l/min respectively (Fig. 1B). Cardiac output measurement by TTE was possible in 72 instances while TPTD allowed measurement in all 113 instances. Hence, TTE was not feasible in 41 instances across 14 patients, including 19 instances in acyanotic and 22 instances in cyanotic patients. Polar analysis revealed acceptable trending. Conclusions TTE derived cardiac output demonstrated good correlation, minimal bias and narrow limits of agreement versus TPTD, and was feasible in most cases. This suggests TTE is an acceptable cardiac output measurement modality post pediatric cardiac surgery, as in adults [5]. TPTD-based continuous cardiac output monitoring might have a complementary role in pediatric cardiac critical care, particularly in high risk cases. Funding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): Institutional Special Research Grant from Postgraduate Institute of Medical Education and Research, Chandigarh, India. Figure 1

Are single-lumen 5Fr and triple-lumen 6Fr PICCs suitable for hemodynamic assessment by trans-pulmonary thermodilution? A pilot study

BackgroundSingle-lumen 4Fr or double-lumen 5Fr power injectable peripherally inserted central catheters (PICCs) are not accurate for trans-pulmonary thermodilution (TPTD), since they overestimate cardiac index and other TPTD-derived parameters when compared with centrally inserted central catheters (CICCs) because of the smaller size of their lumen. We hypothesize that PICCs with larger lumen size may be reliable for the cardiac index assessment using the TPTD.MethodsThis is a single-centre, prospective method–comparison study that included adult patients admitted in ICU who required a calibrated Pulse Contour hemodynamic monitoring system (VolumeView/EV1000™) for circulatory shock and had both PICC and CICC in place. We compared TPTD measurements via single-lumen 5Fr or triple-lumen 6Fr polyurethane power injectable PICCs with triple-lumen 7Fr CICC (reference standard). To rule out biases related to manual injection, measurements were repeated using an automated rapid injection system. We performed Bland–Altman analysis accounting for multiple observations per patient.ResultsA total of 320 measurements were performed in 15 patients. During the manual phase, the cardiac index measured with either single-lumen 5Fr or triple-lumen 6Fr PICCs were comparable with cardiac index measured with triple-lumen 7Fr CICC (3.2 ± 1.04 vs. 3.2 ± 1.06 L/min/m2, bias 2.2% and 3.3 ± 0.8 vs. 3.0 ± 0.7 L/min/m2, bias 8.5%, respectively). During the automated phase, triple-lumen 6Fr PICC slightly overestimated the cardiac index when compared to triple-lumen 7Fr CICC (CI 3.4 ± 0.7 vs. 3.0 ± 0.7 L/min/m2, bias 12.5%; p = 0.012). For both single-lumen 5Fr and triple-lumen 6Fr PICCs, percentage error vs. triple-lumen 7Fr CICC was below 20% (14.7% and 19% during the manual phase and 14.4% and 13.8% during the automated phase, respectively). Similar results were observed for TPTD-derived parameters.ConclusionsDuring hemodynamic monitoring with TPTD, both single-lumen 5Fr PICCs and triple-lumen 6Fr PICCs can be used for cold fluid bolus injection as an alternative to CICC (ClinicalTrials.gov NCT04241926).

Risk factors and the associated limit values for abnormal elevation of extravascular lung water in severely burned adults

BackgroundIncreased extravascular lung water (EVLW) correlates with pulmonary morbidity and mortality in critical illness. The extravascular lung water index (EVLWI), which reflects the degree of EVLW in an individual, increases in the fluid reabsorption stage rather than the initial resuscitation stage in severe burn cases. While many factors contribute to EVLWI variation, the risk factors contributing to its abnormal elevation in severe burns remain unclear. The aim of this study was to identify the risk factors and associated limit values for abnormal elevation of EVLWI during the fluid reabsorption stage in a cohort of severely burned adults. MethodThis prospective, single-center study included only adults with burn sizes≥50% of the total body surface area (TBSA) who were admitted within 24h after burn. Demographic data were collected, and transpulmonary thermodilution (TPTD) measurements and blood biochemistry tests were performed upon admission and up to day (PBD) 9. Risk factors for abnormal EVLWI were analyzed by logistic regression. Receiver operating characteristic (ROC) curves were constructed to determine the optimal cut-offs for each risk factor. ResultsSeventy-two patients were ultimately enrolled, with a mean age of 40.3 years and mean burn size of 69.4% TBSA. EVLWI began to abnormally increase (>7ml/kg) on day 3 and up to PBD 9, indicating that a supranormal EVLWI developed in the fluid reabsorption stage. Several relevant factors were considered, including patient age, burn size, intrathoracic blood volume index (ITBVI), pulmonary vascular permeability index (PVPI), cardiac index (CI), systemic vascular resistance index (SVRI), serum albumin, time of first excision and grafting, and number of operations and daily fluid administration. Among these factors, we found that only burn size and ITBVI were significantly correlated with EVLWI variation and were further identified as the independent risk factors for EVLWI abnormality. ROC analysis showed that the limits for predicting a supranormal EVLWI during the fluid reabsorption stage were 65.5% TBSA for burn size and 845ml/m2 for ITBVI. Patients with burn sizes or ITBVIs higher than the limit showed significantly longer mechanical ventilation time and substantially higher occurrences of acute respiratory distress syndrome (ARDS) and pneumonia within two weeks after burn. ConclusionsBurn size and ITBVI are the independent risk factors for EVLWI abnormality during the fluid reabsorption stage in severely burned adults. The limit values for predicting a supranormal EVLWI in those patients are 65.5% TBSA for burn size and 845ml/m2 for ITBVI.

Sustained low efficiency dialysis should not be interrupted for performing transpulmonary thermodilution measurements

BackgroundTreatment of multiple organ failure frequently requires enhanced hemodynamic monitoring. When renal replacement is indicated, it remains unclear whether transpulmonary thermodilution (TPTD) measurements are influenced by renal replacement therapy (RRT) and whether RRT should be paused for TPTD measurements. Our aim was therefore to investigate the effect of pausing RRT on TPTD results in two dialysis catheter locations.Materials and methodsIn total, 62 TPTD measurements in 24 patients (APACHE: 32 ± 7 [mean ± standard deviation (SD)]) were performed using the PiCCO™ system (Pulsion, Germany). Patients were treated with sustained low efficiency dialysis (SLED; Genius™ system, Fresenius, Germany) as RRT. Measurements were taken during ongoing hemodialysis (HD, HDO), during paused HD (HDP) and immediately after termination of HD and blood restitution (HDT). Dialysis catheters were placed either in the superior vena cava (SVC, 19 times) or in the inferior vena cava (IVC, 5 times). Statistical analysis was performed to assess the effects of the measurement setting, SLED (blood flow rate) and the catheter location, on cardiac index (CI), global end-diastolic volume index (GEDVI) and extravascular lung water index (EVLWI) as measured by TPTD. Multilevel models were used for the analysis due to the triplicate measurements and due to 12 out of 19 SVC and 2 out of 5 IVC patients having more than one TPTD measured.ResultsCI and GEDVI were significantly higher at time point HDP compared to both HDO and HDT. In contrast, values for EVLWI were lower at HDP when compared to HDO and HDT. These findings were independent of the site of dialysis catheter insertion and blood flow rate.ConclusionsPiCCO™ measurements assessed at paused SLED significantly deviate from ongoing and terminated SLED. Therefore, the dialysis system should not be paused for measurements. TPTD measurements in patients with PiCCO monitoring seem sufficiently reliable during ongoing SLED as well as after its termination. An effect of dialysis catheter location (SVC vs IVC) and blood flow rate on PiCCO™ measurements could not be shown.

Quantitative computed tomography in comparison with transpulmonary thermodilution for the estimation of pulmonary fluid status: a clinical study in critically ill patients.

Extravascular lung water (index) (EVLW(I)) can be estimated using transpulmonary thermodilution (TPTD). Computed tomography (CT) with quantitative analysis of lung tissue density has been proposed to quantify pulmonary edema. We compared variables of pulmonary fluid status assessed using quantitative CT and TPTD in critically ill patients. In 21 intensive care unit patients, we performed TPTD measurements directly before and after chest CT. Based on the density data of segmented CT images we calculated the tissue volume (TV), tissue volume index (TVI), and the mean weighted index of voxel aqueous density (VMWaq). CT-derived TV, TVI, and VMWaq did not predict TPTD-derived EVLWI values ≥ 14mL/kg. There was a significant moderate positive correlation between VMWaq and mean EVLWI (EVLWI before and after CT) (r = 0.45, p = 0.042) and EVLWI after CT (r = 0.49, p = 0.025) but not EVLWI before CT (r = 0.38, p = 0.086). There was no significant correlation between TV and EVLW before CT, EVLW after CT, or mean EVLW. There was no significant correlation between TVI and EVLWI before CT, EVLWI after CT, or mean EVLWI. CT-derived variables did not predict elevated TPTD-derived EVLWI values. In unselected critically ill patients, variables of pulmonary fluid status assessed using quantitative CT cannot be used to predict EVLWI.

Noninvasive oscillometric cardiac output determination in the intensive care unit \u2013 comparison with invasive transpulmonary thermodilution

Assessment of the cardiac output (CO) is usually performed with invasive techniques requiring specialized equipment in the intensive care unit (ICU). With TEL-O-GRAPH (TG), CO can be derived from the oscillometrically obtained brachial pulse wave during the measurement of brachial blood pressure. CO and stroke volume (SV) determinations with TG were compared with transpulmonary thermodilution measurements with the PICCO system (PICCO) in 38 haemodynamically unstable ICU patients with a total of 84 comparison measurements performed. SV (33.3 ± 9.0 ml/m2 vs. 44.3 ± 14.4 ml/m2, p < 0.001) and CO (2.7 ± 0.5 l/min/m2 vs. 3.8 ± 1.2 l/min/m2, p < 0.001) were underestimated significantly with TG and oscillometric brachial systolic blood pressure (BP) was significantly lower and diastolic BP significantly higher than invasive femoral artery pressure. A linear correlation was found between CO dimension and CO underestimation with TG. Correct tracking of CO changes with a fluid challenge was possible in 69.5% of measurements. Oscillometric noninvasive CO is possible in the ICU, but accuracy and precision of this new method are lacking. Implementation of a correction factor accounting for the linear increase in CO underestimation observed with increasing CO could improve CO assessment with TG in haemodynamically unstable patients.

Evaluation of Reperfusion Pulmonary Edema by Extravascular Lung Water Measurements After Pulmonary Endarterectomy.

Reperfusion pulmonary edema is a specific complication of pulmonary endarterectomy for chronic thromboembolic pulmonary hypertension. Extravascular lung water measurement may be valuable for diagnosing reperfusion pulmonary edema. The primary objective of this study was to describe and assess the clinical significance of extravascular lung water variations after pulmonary endarterectomy. Prospective observational study. Nineteen-bed cardiothoracic ICU. Consecutive patients who were hemodynamically stable after pulmonary endarterectomy were divided into two groups based on whether their preoperative pulmonary vascular resistance indicated severe or nonsevere chronic thromboembolic pulmonary hypertension (> 900 or ≤ 900 dynes·s/cm, respectively). Hemodynamic variables obtained by right heart catheterization and transpulmonary thermodilution measurements were recorded 1 hour, 1 day, and 2 days after pulmonary endarterectomy. Extravascular lung water was indexed to predicted body weight (EVLWPBW). We studied 31 patients. Overall, 26 patients (84%) experienced reperfusion pulmonary edema during the first 72 hours after pulmonary endarterectomy. EVLWPBW significantly increased between the first hour after pulmonary endarterectomy and day 2 (10.2 ± 2.6 vs 11.4 ± 3.6; p = 0.03). EVLWPBW measured at the first hour after pulmonary endarterectomy is closely associated with reperfusion pulmonary edema occurrence in the next 48 hours (area under the receiver-operating characteristics curve = 0.88 ± 0.07). EVLWPBW correlated with duration of mechanical ventilation (ρ = 0.59; p < 0.0001) and ICU stay (ρ = 0.52; p < 0.0001). Patients with severe chronic thromboembolic pulmonary hypertension (n = 15) had higher EVLWPBW values at day 2 compared with those without (n = 16) (13.2 ± 3.6 vs 9.7 ± 2.7 mL/kg; p = 0.004). Cardiac output was measured simultaneously by pulmonary artery catheter and aortic transpulmonary thermodilution on 92 occasions; agreement was good, with a bias of 0.50 ± 0.95 L/min (95% CI, -1.36-2.36). Accurate extravascular lung water measurements were obtained after pulmonary endarterectomy. Extravascular lung water may prove valuable for diagnosing reperfusion pulmonary edema after pulmonary endarterectomy and had prognostic value. Extravascular lung water values were significantly higher in patients with severe compared with nonsevere chronic thromboembolic pulmonary hypertension.

Applicability of stroke volume variation in patients of a general intensive care unit: a longitudinal observational study.

Sinus rhythm (SR) and controlled mechanical ventilation (CV) are mandatory for the applicability of respiratory changes of the arterial curve such as stroke volume variation (SVV) to predict fluid-responsiveness. Furthermore, several secondary limitations including tidal volumes <8mL/kg and SVV-values within the "gray zone" of 9-13% impair prediction of fluid-responsiveness by SVV. Therefore, we investigated the prevalence of these four conditions in general ICU-patients. This longitudinal observational study analyzed a prospectively maintained haemodynamic database including 4801 transpulmonary thermodilution and pulse contour analysis measurements of 278 patients (APACHE-II 21.0±7.4). The main underlying diseases were cirrhosis (32%), sepsis (28%), and ARDS (17%). The prevalence of SR and CV was only 19.4% (54/278) in the first measurements (primary endpoint), 18.8% (902/4801) in all measurements and 26.5% (9/34) in measurements with MAP<65mmHg and CI<2.5 L/min/m2 and vasopressor therapy. In 69.1% (192/278) of the first measurements and in 65.9% (3165/4801) of all measurements the patients had SR but did not have CV. In 1.8% (5/278) of the first measurements and in 2.5% (119/4801) of all measurements the patients had CV but lacked SR. In 9.7% (27/278) of the first measurements and in 12.8% (615/4801) of all measurements the patients did neither have SR nor CV. Only 20 of 278 (7.2%) of the first measurements and 8.2% of all measurements fulfilled both major criteria (CV, SR) and both minor criteria for the applicability of SVV. The applicability of SVV in ICU-patients is limited due to the absence of mandatory criteria during the majority of measurements.

Transpulmonary thermodilution (PiCCO) measurements in children without cardiopulmonary dysfunction: large interindividual variation and conflicting reference values.

The PiCCO system, based on transpulmonary thermodilution, is one of the few tools available for continuous hemodynamic monitoring in children. However, published data for some of the derived variables reveal indexed values that seem questionable. The aim of this study was to collect data from hemodynamically normal children and compare these to existing reference values. Furthermore, we sought to explore if indexing some of the variables differently could improve the clinical application of the obtained values. This is a prospective observational study in a tertiary university hospital including 31 children without cardiopulmonary disease scheduled for major neurosurgery. Measurements were performed after induction of general anesthesia. Median age was 8 months. PiCCO-derived median Cardiac Index (CI) was 3.8 l · min(-1) · m(-2) (range 2.6-6.6), reference range 3.0-5.0, median Global End-Diastolic Volume Index (GEDVI) was 366 ml · m(-2) (range 269-685), reference range 680-800, whereas median Extravascular Lung Water Index (EVLWI) was 12 ml · kg(-1) (range 7-31), reference range 3-7. All measured variables had a high interindividual variation, especially in children weighing less than 15 kg. Values obtained by the PiCCO system in children have a wide range, and should therefore be interpreted with caution. Current reference values published for GEDVI and EVLWI are not applicable in children; the former is too high and the latter too low, and should not guide clinical practice. Indexing by other physiological indices may reduce this problem. Using current variables, we find GEDVI 280-590 ml · m(-2) and ELWI 7-27 ml · kg(-1) to be typical ranges for children.

N-terminal-pro-brain natriuretic peptide elevations in the course of septic and non-septic shock reflect systolic left ventricular dysfunction assessed by transpulmonary thermodilution

BackgroundThe cardiac correlates, if any, of N-terminal probrain natriuretic peptide (NT-proBNP) levels in septic and non-septic shock patients remain controversial. MethodsIn the 38 septic and 22 non-septic shock patients in the transpulmonary thermodilution arm of a previous 2-center randomized controlled trial comparing pulmonary artery catheterization with transpulmonary thermodilution, serial (daily for 3days) and paired measurements (n=145) were obtained of NT-proBNP and transpulmonary dilution variables as global ejection fraction (GEF), left ventricular preload-recruitable stroke work (PRSW) and diastolic compliance. ResultsElevated NT-proBNP inversely related to low GEF and PRSW in pooled data (r=−0.45, P<0.001). The 72h course of NT-proBNP was inversely associated with PRSW, independent of age, gender, creatinine, norepinephrine treatment and diastolic compliance, without differences between septic and non-septic shock. Over the 72h study period, NT-proBNP levels were higher in 28day non-survivors than survivors, independent of type of shock and disease severity. ConclusionsIn septic and non-septic shock, NT-proBNP elevations reflect systolic left ventricular dysfunction and are associated with a poor outcome. They may help recognition of cardiac dysfunction in shock and its management when invasive hemodynamic monitoring is not yet instituted.

Impact of misplaced subclavian vein catheter into jugular vein on transpulmonary thermodilution measurement variables.

The subclavian vein (SCV) is usually used to inject the indicator of cold saline for a transpulmonary thermodilution (TPTD) measurement. The SCV catheter being misplaced into the internal jugular (IJV) vein is a common occurrence. The present study explores the influence of a misplaced SCV catheter on TPTD variables. Thirteen severe acute pancreatitis (SAP) patients with malposition of the SCV catheter were enrolled in this study. TPTD variables including cardiac index (CI), global end-diastolic volume index (GEDVI), intrathoracic blood volume index (ITBVI), and extravascular lung water index (EVLWI) were obtained after injection of cold saline via the misplaced SCV catheter. Then, the misplaced SCV catheter was removed and IJV access was constructed for a further set of TPTD variables. Comparisons were made between the TPTD results measured through the IJV and misplaced SCV accesses. A total of 104 measurements were made from TPTD curves after injection of cold saline via the IJV and misplaced SCV accesses. Bland-Altman analysis demonstrated an overestimation of +111.40 ml/m(2) (limits of agreement: 6.13 and 216.70 ml/m(2)) for GEDVI and ITBVI after a misplaced SCV injection. There were no significant influences on CI and EVLWI. The biases of +0.17 L/(min·m(2)) for CI and +0.17 ml/kg for EVLWI were revealed by Bland-Altman analysis. The malposition of an SCV catheter does influence the accuracy of TPTD variables, especially GEDVI and ITBVI. The position of the SCV catheter should be confirmed by chest X-ray in order to make good use of the TPTD measurements.

The effects of advanced monitoring on hemodynamic management in critically ill patients: a pre and post questionnaire study

In critically ill patients, many decisions depend on accurate assessment of the hemodynamic status. We evaluated the accuracy of physicians' conventional hemodynamic assessment and the impact that additional advanced monitoring had on therapeutic decisions. Physicians from seven European countries filled in a questionnaire in patients in whom advanced hemodynamic monitoring using transpulmonary thermodilution (PiCCO system; Pulsion Medical Systems SE, Feldkirchen, Germany) was going to be initialized as part of routine care. The collected information included the currently proposed therapeutic intervention(s) and a prediction of the expected transpulmonary thermodilution-derived variables. After transpulmonary thermodilution measurements, physicians recorded any changes that were eventually made in the original therapeutic plan. A total of 315 questionnaires pertaining to 206 patients were completed. The mean difference (±standard deviation; 95% limits of agreement) between estimated and measured hemodynamic variables was -1.54 (±2.16; -5.77 to 2.69) L/min for the cardiac output (CO), -74 (±235; -536 to 387) mL/m(2) for the global end-diastolic volume index (GEDVI), and -0.5 (±5.2; -10.6 to 9.7) mL/kg for the extravascular lung water index (EVLWI). The percentage error for the CO, GEDVI, and EVLWI was 66, 64, and 95%, respectively. In 54% of cases physicians underestimated the actual CO by more than 20%. The information provided by the additional advanced monitoring led 33, 22, 22, and 13% of physicians to change their decisions about fluids, inotropes, vasoconstrictors, and diuretics, respectively. The limited clinical ability of physicians to correctly assess the hemodynamic status, and the significant impact that more physiological information has on major therapeutic decisions, support the use of advanced hemodynamic monitoring in critically ill patients.

The influence of continuous venovenous hemofiltration on parameter measurement by the transpulmonary thermodilution technique

To evaluate the influence of continuous venovenous hemofiltration (CVVH) on measurement of transpulmonary thermodilution parameters. A prospective observational study was conducted. Fifty-six patients who received CVVH and hemodynamic monitoring at the same time admitted to the Department of Critical Care Medicine of Tianjin Third Central Hospital from July 2012 to July 2014 were enrolled. In all the patients, the dialysis catheter was inserted through the femoral vein, and transpulmonary thermodilution measurements were performed by pulse indicator continuous cardiac output (PiCCO) monitoring technology at the same time. Mean arterial pressure (MAP), central blood temperature, cardiac index (CI), global end-diastolic volume index (GEDVI), intrathoracic blood volume index (ITBVI) and extravascular lung water index (EVLWI) were measured before CVVH, immediately after CVVH, and 30 minutes after CVVH, respectively. Results In the 56 patients, there were 36 males and 20 females, (66 ± 16) years of old, height of (172 ± 6) cm, body weight of (68 ± 10) kg. The acute physiology and chronic health evaluation II (APACHE II) scores was 26 ± 6. After CVVH, the central blood temperature was gradually decreased, and blood temperature at 30 minutes after CVVH was significantly lower than that before CVVH (degrees C : 37.17 ± 1.06 vs. 37.57 ± 1.26, P < 0.01). There were no significant changes in MAP and EVLWI before and after CVVH the MAP was (89 ±20), (86 ± 16), (90 ± 17) mmHg ( 1 mmHg = 0.133 kPa) at three time points respectively, and EVLWI was (9.4 ± 3.2, (9.3 ± 3.0), (9.4 ± 2.9) mL/kg, respectively. After CVVH, CI, GEDVI and ITBVI showed a gradual downward tendency. Compared with those before CVVH, the decline of CI, GEDVI, and ITBVI immediately after CVVH was not statistically significant [CI (mL x s (-1) x m(-2): 62.18 ± 24.34 vs 63.85 ± 21.84, GEDVI (mL/m2): 705 ± 103 vs 727 ± 100, ITBVI (mL/m2): 881 ± 129 vs 908 ± 125, all P > 0.05]. CI, GEDVI, ITBVI at 30 minutes after CVVH were significantly decreased [CI mL x s(-1) x m(-2)): 57.84 ± 20.50 vs 63.85 ± 21.84, GEDVI (mL/m2): 681 ± 106 vs. 727 ± 100, ITBVI (mL/m2): 851 ± 133 vs. 908 ± 125, all P < 0.05]. CVVH was associated with a decline of 6.01 mL x s(-1) x m(-2) at 30 minutes after CVVH [95% confidence interval (95% CI)) = -10.67 to -1.50, P = 0.011]. The declines of GEEDVI and ITBVI were observed with 46 mL/m2 (95% CI = -81 to - 11, P = 0.014), 57 mL/m2 (95% CI = -101 to -13, P = 0.014) respectively 30 minutes after CVVH. CVVH had no significant effect on the transpulmonary thermodilution measurement of CI, GEDVI, ITBVI and EVLWI. Thirty minutes after the start of CVVH, CI, GEDVI was decreased significantly, but had no effect on EVLWI.

Influence of different infracardial positions of central venous catheters in hemodynamic monitoring using the transpulmonal thermodilution method.

Hemodynamic measurements are often conducted by the transpulmonary thermodilution (TPTD)-based PiCCO(®)-system. This requires a central-venous (CVC) and a thermistor-tipped arterial catheter, usually placed in the femoral artery. In certain clinical situations, CVC devices have to be placed in the inferior vena cava. However, little is known about the influence of different CVC positions (i.e. ipsi- vs. contra-lateral to the arterial catheter) on the accuracy of the TPTD measurement results. In this prospective observational study surgical intensive care unit patients who had been inserted with CVCs either into the superior (CVCVCS) or the inferior vena cava (CVCinf) in addition to an arterial PiCCO(®)-catheter, were enrolled. Patients were then divided into two groups: Group I was provided with a CVC in the contralateral (CVCcontra) and Group II in the ipsilateral (CVCipsi) inferior vena cava. Thermodilution via injection of ice-cold saline was then performed via CVCsup and CVCinf. Bland-Altman analysis for cardiac index (CI), extra-vascular lung water index (EVLWI) and global end-diastolic volume index (GEDVI) were employed. Additional correction formulas for femorally assed parameters were determined. In a total of 28 patients, bias (limits of agreement) for measurements of CI in CVCcontra was found to be +0.2 (-0.4; +0.9)and +0.3 (-0.4; +1.0) L/min/m(2) in CVCipsi. GEDVI showed a bias of +274.8 (-47.3; +596.9) mL/m(2) in CVCcontra and +274.7 (-100.7; +650.1) mL/m(2) in CVCipsi. The mean EVLWI were 9.4±4.3mL/kg for EVLWIVCS and 10.7±5.2mL/kg for EVLWIinf. The LoA yielded at -3.4 and +6.1mL/kg with a bias of +1.3mL/kg. Percentage errors revealed clinically acceptable limits for CI and GEDVI, but not for EVLWI. Using TPTD via an infracardial central vein, measurements of CI showed high accuracy and precision while GEDVI measurements were precise with a lower accuracy, irrespective of the position of the infracardial CVC.

Influence of echinocandin administration on hemodynamic parameters in medical intensive care unit patients: a single center prospective study.

Fungal infections present a constant risk to critically ill and immunocompromised patients. Therefore, treatment guidelines recommend echinocandins as first-line antifungals in critically ill patients to improve patient outcomes. Echinocandins are usually well tolerated; nevertheless, rare adverse events can occur. There are reports of temporary deterioration of hemodynamic parameters during loading doses, especially in critically ill patients. The objective of this study is to analyze the hemodynamic changes during administration of the echinocandin antifungals, caspofungin and anidulafungin, in medical intensive care unit patients. A prospective study in medical ICU patients receiving echinocandins was monitored using single-indicator transpulmonary thermodilution (TPTD). TPTD measurements were performed immediately before, directly after, and 4 h after echinocandins on two following days. Mean arterial pressure and also diastolic blood pressure showed significant changes (p < 0.042 and p < 0.007) after echinocandin application in the measurement immediately after application, but not after 4 h. Basic hemodynamic parameters as well as the TPTD-derived cardiac function parameters did not significantly change after echinocandin application at all. In patients with the need for norepinephrine therapy, the vasopressor dose was not statistically significantly altered. To conclude, administration of echinocandins in this observed study population is safe, even in severely critically ill patients if application rules of these agents are followed. However, adverse effects could be observed and practitioners should be cognizant of these effects. These observations can be optimized by high-level assessments, such as the pulse contour cardiac output monitoring, and clinicians should continue to be vigilant with cardiac monitoring of patients receiving echinocandin antifungals.