Noninvasive Assessment of Cardiac Output in Advanced Heart Failure and Heart Transplant Candidates Using the Bioreactance Method.

OBJECTIVES: The aim of the present study was to assess the validity and trending ability of the bioreactance method in estimating cardiac output at rest and in response to stress in advanced heart failure patients and heart transplant candidates. DESIGN: This was a prospective single-center study. SETTING: This study was conducted at the heart transplant center at the Freeman Hospital, Newcastle upon Tyne, UK. PARTICIPANTS: Eighteen patients with advanced chronic heart failure due to reduced left ventricular ejection fraction (19 ± 7%), and peak oxygen consumption 12.3 ± 3.9 mL/kg/min. INTERVENTIONS: Participants underwent right heart catheterization using the Swan-Ganz catheter. MEASUREMENTS AND MAIN RESULTS: Cardiac output was measured simultaneously using thermodilution and bioreactance at rest and during active straight leg raise test to volitional exertion. There was no significant difference in cardiac index values obtained by the thermodilution and bioreactance methods (2.26 ± 0.59 v 2.38 ± 0.50 L/min, p > 0.05) at rest and peak straight leg raise test (2.92 ± 0.77 v 3.01 ± 0.66 L/min, p > 0.05). In response to active leg raise test, thermodilution cardiac output increased by 22% and bioreactance by 21%. There was also a strong relationship between cardiac outputs from both methods at rest (r = 0.88, p < 0.01) and peak straight leg raise test (r = 0.92, p < 0.01). Cartesian plot analysis showed good trending ability of bioreactance compared with thermodilution (concordance rate = 93%) CONCLUSIONS: `Cardiac output measured by the bioreactance method is comparable to that from the thermodilution method. Bioreactance method may be used in clinical practice to assess hemodynamics and improve management of advanced heart failure patients undergoing heart transplant assessment.

Non-invasive assessment of central venous pressure in heart failure: a systematic prospective comparison of echocardiography and Swan-Ganz catheter.

Assessing hemodynamics, especially central venous pressure (CVP), is essential in heart failure (HF). Right heart catheterization (RHC) is the gold-standard, but non-invasive methods are also needed. However, the role of 2-dimensional echocardiography (2DE) remains uncertain, and 3-dimensional echocardiography (3DE) is not always available. This study investigated standardized and breathing-corrected assessment of inferior vena cava (IVC) volume using echocardiography (2DE and 3DE) versus CVP determined invasively using RHC. Sixty consecutive HF patients were included (82% male, age 54 ± 11 years, New York Heart Association class 2.23 ± 0.8, ejection fraction 46 ± 18.4%, brain natriuretic peptide 696.93 ± 773.53 pg/mL). All patients underwent Swan-Ganz RHC followed by 2DE and 3DE, and IVC volume assessment. On 2DE, mean IVC size was 18.3 ± 5.5 mm and 13.8 ± 6 mm in the largest deflection and shortest distention, respectively. Mean CVP from RHC was 9.3 ± 5.3 mmHg. Neither 2DE nor 3DE showed acceptable correlation with invasively measured CVP; IVC volume acquisition showed optimal correlation with RHC CVP (0.64; 95% confidence interval 0.46-0.77), with better correlation when mitral valve early diastole E wave and right ventricular end-diastolic diameter were added. Using a CVP cut-point of 10 mmHg, receiver operating characteristic curve showed true positivity (specificity) of 0.90 and sensitivity of 62% for predicting CVP. A validation study confirmed these findings and verified the high predictive value of IVC volume assessment. Neither 2DE nor 3DE alone can reliably mirror CVP, but IVC volume acquisition using echocardiography allows non-invasive and adequate approximation of CVP. Correlation with invasively measured pressure was strongest when CVP is > 10 mmHg.

Trends in Utilization and Outcomes of Pulmonary Artery Catheterization in Heart Failure With and Without Cardiogenic Shock.

BACKGROUND: The pulmonary artery catheter (PAC) has been used in a wide range of critically ill patients. It is not indicated for routine care of heart failure (HF), but its role in cardiogenic shock (CS) has not been clarified. METHODS AND RESULTS: We conducted a retrospective cohort study with the use of the National Inpatient Sample and identified a total of 9,431,944 adult patients admitted from 2004 to 2014 with the primary diagnosis of HF (n = 8,516,528) or who developed CS (n = 915,416) during the index hospitalization. Overall, patients with PAC had increased hospital costs, length of stay, and mechanical circulatory support use. In patients with HF, PAC use was associated with higher mortality (9.9% vs 3.3%, OR 3.96; P < .001) but the excess of mortality declined over time. In those with CS, PAC was associated with lower mortality (35.1% vs 39.2%, OR 0.91; P < .001) and in-hospital cardiac arrest (14.9% vs 18.3%, OR 0.77; P < .001); this paradox persisted after propensity score matching. CONCLUSIONS: The use of PAC in CS has decreased from 2004 to 2014, although its use is now associated with improved outcomes, which may reflect better selection of patients or better use of the information to guide therapies. Our data provide reassurance that PAC use in this population is an appropriate strategy.

Noninvasive assessment of Cardiac Index using impedance cardiography during liver transplantation surgery: a comparison with pulmonary artery thermodilution.

BACKGROUND: Liver transplantation (LT) is a high-risk surgery associated with significant hemodynamic changes requiring advanced hemodynamic monitoring. Pulmonary Artery Catheter (PAC) is still considered as a gold-standard for Cardiac Index (CI) measurement during LT despite association with an increased risk of complications. Noninvasive impedance cardiography (ICG) could be an interesting alternative tool for CI monitoring. The aim of this study was to compare the precision and trending ability of ICG versus PAC methods during LT. METHODS: Patients undergoing LT were prospectively included. CI was measured with PAC and ICG at 4 time points (T1: before surgical incision, T2: during anhepatic phase, T3: after portal reperfusion, T4: during wound closure). Bias and percentage error (PE) between CI measured with PAC and ICG were analyzed with the Bland-Altman method for repeated measurements. Trending ability was studied with 4-quadrant and polar plots and correlation coefficient. RESULTS: We included 43 patients with 156 measures. Mean bias was -0.95 L.min-1.m-2, SD±1.07, limits of agreement -3.73 to 1.83 L.min-1.m-2 and PE 58%. There was a significant increase in bias during LT (P<0.001). Assessment of trending ability displayed a concordance rate of 72% on the 4-quadrant plot and a mean angular bias of -8.4° (SD±28°) and radial limits of agreement ±55° on the polar plot. CONCLUSIONS: CI measurements using ICG exhibited a low precision and a poor trending ability when compared to thermodilution method during LT. Consequently, ICG is not an adequate hemodynamic tool to monitor CI during LT.

National Trends in Use and Outcomes of Pulmonary Artery Catheters Among Medicare Beneficiaries, 1999-2013.

Importance: Recent studies have observed an increase in the rate of pulmonary artery catheter (PAC) use in heart failure admissions. Little is known about the national trends in other previously common indications for PAC placement, PAC use overall, or outcomes associated with PAC placement. Objective: To determine national trends in PAC use overall as well as across sociodemographic groups and key clinical conditions, including acute myocardial infarction, heart failure, and respiratory failure. Design, Setting, and Participants: Centers for Medicare and Medicaid Services inpatient claims data and International Classification of Diseases, Ninth Revision, Clinical Modification codes were used to conduct a serial cross-sectional cohort study between January 1, 1999, and December 31, 2013, identifying hospitalizations during which a PAC was placed. Data analysis was conducted from September 25, 2015, to April 10, 2017. Main Outcomes and Measures: Rate of use of a PAC per 1000 admissions, 30-day mortality, and length of stay. Results: Among the 68 374 904 unique Medicare beneficiaries in the study, there were 469 582 hospitalizations among 457 193 patients (204 232 women and 252 961 men; mean [SD] age, 76.3 [6.9] years) during which a PAC was placed. There was a 67.8% relative decrease in PAC use (6.28 per 1000 admissions in 1999 to 2.02 per 1000 admissions in 2013; P < .001), with 2 distinct trends: significant year-on-year decreases from 1999 to 2011, followed by stable use through 2013. There was variation in rates of PAC use across race/ethnicity, age, and sex, but use decreased across all subgroups. Although there were sustained decreases in PAC use for acute myocardial infarction (20.0 PACs placed per 1000 admissions in 1999 to 5.2 in 2013 [74.0% reduction]; P < .001 for trend) and respiratory failure (29.9 PACs placed per 1000 admission in 1999 to 2.3 in 2013 [92.3% reduction]; P < .001 for trend) during the study period, there was an initial decrease in PAC use in heart failure, with a nadir in 2009 followed by a subsequent increase (9.1 PACs placed per 1000 admissions in 1999 to 4.0 in 2009 to 5.8 in 2013). In-hospital mortality, 30-day mortality, and length of stay decreased during the study period. Conclusions and Relevance: In the wake of mounting evidence suggesting a lack of benefit to the routine use of PACs, there has been a de-adoption of PAC use overall and across sociodemographic groups but heterogeneity in patterns of use across clinical conditions. The clinical outcomes of patients with PACs have significantly improved. These findings raise important questions about the optimal use of PACs and the drivers of the observed trends.

Association Between Intensive Care Unit Utilization During Hospitalization and Costs, Use of Invasive Procedures, and Mortality.

IMPORTANCE: Maximizing the value of critical care services requires understanding the relationship between intensive care unit (ICU) utilization, clinical outcomes, and costs. OBJECTIVE: To examine whether hospitals had consistent patterns of ICU utilization across 4 common medical conditions and the association between higher use of the ICU and hospital costs, use of invasive procedures, and mortality. DESIGN, SETTING, AND PARTICIPANTS: Retrospective cohort study of 156 842 hospitalizations in 94 acute-care nonfederal hospitals for diabetic ketoacidosis (DKA), pulmonary embolism (PE), upper gastrointestinal bleeding (UGIB), and congestive heart failure (CHF) in Washington state and Maryland from 2010 to 2012. Hospitalizations for DKA, PE, UGIB, and CHF were identified from the presence of compatible International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes. Multilevel logistic regression models were used to determine the predicted hospital-level ICU utilization during hospitalizations for the 4 study conditions. For each condition, hospitals were ranked based on the predicted ICU utilization rate to examine the variability in ICU utilization across institutions. MAIN OUTCOMES AND MEASURES: The primary outcomes were associations between hospital-level ICU utilization rates and risk-adjusted hospital mortality, use of invasive procedures, and hospital costs. RESULTS: The 94 hospitals and 156 842 hospitalizations included in the study represented 4.7% of total hospitalizations in this study. ICU admission rates ranged from 16.3% to 81.2% for DKA, 5.0% to 44.2% for PE, 11.5% to 51.2% for UGIB, and 3.9% to 48.8% for CHF. Spearman rank coefficients between DKA, PE, UGIB, and CHF showed significant correlations in ICU utilization for these 4 medical conditions among hospitals (ρ ≥ 0.90 for all comparisons; P < .01 for all). For each condition, hospital-level ICU utilization rate was not associated with hospital mortality. Use of invasive procedures and costs of hospitalization were greater in institutions with higher ICU utilization for all 4 conditions. CONCLUSIONS AND RELEVANCE: For medical conditions where ICU care is frequently provided, but may not always be necessary, institutions that utilize ICUs more frequently are more likely to perform invasive procedures and have higher costs but have no improvement in hospital mortality. Hospitals had similar ICU utilization patterns across the 4 medical conditions, suggesting that systematic institutional factors may influence decisions to potentially overutilize ICU care. Interventions that seek to improve the value of critical care services will need to address these factors that lead clinicians to admit patients to higher levels of care when equivalent care can be delivered elsewhere in the hospital.

[The impact of closed system and 7 days intravascular administration set replacement on catheter related infections in a general intensive care unit: a before-after study]. / Efficacia della linea chiusa e sostituzione delle linee infusionali ogni 7 giorni sulle infezioni da catetere vascolare in una terapia intensiva polivalente: studio pre-post.

INTRODUCTION: The incidence of catheter related Bloodstream infections (BSI) is high in intensive care units (ICU). AIM: To evaluate the BSI rate in a population of patients admitted to a General ICU before and after the implementation of the 2011 CDC guidelines. METHODS: Retrospective observational study on patients admitted from January 2009 to December 2013. The infusion and monitoring lines were changed every 96 hours for the first 30 months, and every 7 days for the next 30. In all patients a closed infusion line with needle-free connectors pressure was used (Microclave). The following catheters were considered in the study: central venous catheter (CVC), arterial cannula (ART) and Swan Ganz catheter (SG). RESULTS: During the period with change every 96 hours 15 BSI were observed over 13395 catheters/days (C/D), 1.12 per 1000 C/D, while when lines where changed every 7 days 11 BSI were observed over 13120 C/D, 0.83 per 1000 C/D. A statistically significant reduction of BSI was observed in SG catheters (4.17 vs. no BSI p = 0.02), while the CVCS (1.12 vs 1.45 - p = 0.37) and ART (0.35 vs 0.36 - p = 0.61) infection rates remained unchanged. CONCLUSIONS: The replacement of infusion lines every 7 days in our sample did not increase the BSI, helping to reduce the costs.

Utilization of catheter-directed thrombolysis in pulmonary embolism and outcome difference between systemic thrombolysis and catheter-directed thrombolysis.

OBJECTIVE: The aim of the study was to assess the utilization of catheter-directed thrombolysis (CDT) and its comparative effectiveness against systemic thrombolysis in acute pulmonary embolism (PE). BACKGROUND: Contemporary real world data regarding utilization and outcomes comparing systemic thrombolysis with CDT for PE is sparse. METHODS: We queried the Nationwide Inpatient Sample from 2010 to 2012 using the ICD-9-CM diagnosis code 415.11, 415.13, and 415.19 for acute PE. We used propensity score analysis to compare outcomes between systemic thrombolysis and CDT. Primary outcome was in-hospital mortality. Secondary outcome was combined in-hospital mortality and intracranial hemorrhage (ICH). RESULTS: Out of 110,731 patients hospitalized with PE, we identified 1,521 patients treated with thrombolysis, of which 1,169 patients received systemic thrombolysis and 352 patients received CDT. After propensity-matched comparison, primary and secondary outcomes were significantly lower in the CDT group compared to systemic thrombolysis (21.81% vs. 13.36%, OR 0.55, 95% CI 0.36-0.85, P value = 0.007) and (22.89% vs. 13.36%, OR 0.52, 95% CI 0.34-0.80, P value = 0.003), respectively. The median length of stay [7 days, interquartile range (IQR) (5-9 days) vs. 7 days, IQR (5-10 days), P = 0.17] was not significant between the two groups. The CDT group had higher cost of hospitalization [$17,218, IQR ($12,272-$23,906) vs. $23,799, IQR ($17,892-$35,338), P < 0.001]. Multivariate analysis identified increasing age, saddle PE, cardiopulmonary arrest, and Medicaid insurance as independent predictors of in-hospital mortality. CONCLUSIONS: CDT was associated with lower in-hospital mortality and combined in-hospital mortality and ICH.

Use of pulmonary artery catheter in coronary artery bypass graft. Costs and long-term outcomes.

BACKGROUND: Pulmonary artery catheters (PAC) are used widely to monitor hemodynamics in patients undergoing coronary bypass graft (CABG) surgery. However, recent studies have raised concerns regarding both the effectiveness and safety of PAC. Therefore, our aim was to determine the effects of the use of PAC on the short- and long-term health and economic outcomes of patients undergoing CABG. METHODS: 1361 Chinese patients who consecutively underwent isolated, primary CABG at the Cardiovascular Institute of Fuwai Hospital from June 1, 2012 to December 31, 2012 were included in this study. Of all the patients, 453 received PAC during operation (PAC group) and 908 received no PAC therapy (control group). Short-term and long-term mortality and major complications were analyzed with multivariate regression analysis and propensity score matched-pair analysis was used to yield two well-matched groups for further comparison. RESULTS: The patients who were managed with PAC more often received intraoperative vasoactive drugs dopamine (70.9% vs. 45.5%; P<0.001) and epinephrine (7.7% vs. 2.6%; P<0.001). In addition, costs for initial hospitalization were higher for PAC patients ($14,535 vs. $13,873, respectively, p = 0.004). PAC use was neither associated with the perioperative mortality or major complications, nor was it associated with long-term mortality and major adverse cardiac and cerebrovascular events. In addition, comparison between two well-matched groups showed no significant differences either in baseline characteristics or in short-term and long-term outcomes. CONCLUSIONS: There is no clear indication of any benefit or harm in managing CABG patients with PAC. However, use of PAC in CABG is more expensive. That is, PAC use increased costs without benefit and thus appears unjustified for routine use in CABG surgery.

The global health and economic burden of hospitalizations for heart failure: lessons learned from hospitalized heart failure registries.

Heart failure is a global pandemic affecting an estimated 26 million people worldwide and resulting in more than 1 million hospitalizations annually in both the United States and Europe. Although the outcomes for ambulatory HF patients with a reduced ejection fraction (EF) have improved with the discovery of multiple evidence-based drug and device therapies, hospitalized heart failure (HHF) patients continue to experience unacceptably high post-discharge mortality and readmission rates that have not changed in the last 2 decades. In addition, the proportion of HHF patients classified as having a preserved EF continues to grow and may overtake HF with a reduced EF in the near future. However, the prognosis for HF with a preserved EF is similar and there are currently no available disease-modifying therapies. HHF registries have significantly improved our understanding of this clinical entity and remain an important source of data shaping both public policy and research efforts. The authors review global HHF registries to describe the patient characteristics, management, outcomes and their predictors, quality improvement initiatives, regional differences, and limitations of the available data. Moreover, based on the lessons learned, they also propose a roadmap for the design and conduct of future HHF registries.

The current state of fellowship training in pulmonary artery catheter placement and data interpretation: a national survey of pulmonary and critical care fellowship program directors.

PURPOSE: Given decreasing use of pulmonary artery (PA) catheterization, we sought to evaluate whether current pulmonary and critical care fellows have adequate opportunity to obtain proficiency in PA catheter placement and data interpretation. METHODS: All US pulmonary and critical care program directors were invited to participate in an anonymous online survey regarding current training opportunities in PA catheterization. RESULTS: The response rate was 51% (69/136). Eighty-three percent reported that the number of PA catheterizations performed by fellows within their program has decreased in the past decade. Fifty-four percent estimated that their fellows currently participate in less than 10 supervised procedures during fellowship. The most frequently identified barriers to training were procedure volume and reluctance to place PA catheters in the medical intensive care unit. Forty-three percent of respondents agreed that training in PA catheter placement is currently adequate within their program, and 55% agreed that training in data interpretation is adequate. Only 39% of respondents believe that PA catheter placement should continue to be an Accreditation Council for Graduate Medical Education training requirement. CONCLUSIONS: Many current pulmonary and critical care fellows do not have the opportunity to gain proficiency in PA catheterization. Fellowship training programs should consider alternate means of training fellows in PA catheter data interpretation, such as simulation.

Critical reappraisal of pulmonary artery catheterization and invasive hemodynamic assessment in acute heart failure.

Use of the pulmonary artery catheter (PAC) in the management of heart failure has declined precipitously despite guideline-supported indications, especially among patients hospitalized with acute heart failure (HF) syndromes. Here, the authors critically review the current role of the PAC and the management of patients with HF, and discuss the role of the PAC in the development of new therapies for HF. Pulmonary artery catheterization is a safe procedure when performed by experienced operators, and invasive hemodynamic evaluation with the PAC is recommended in select clinical settings. The PAC may have a unique role in identifying high-risk HF patients with persistent hemodynamic abnormalities during hospitalization. Early-phase trials of novel therapies to improve outcomes in patients with acute HF should include an assessment of hemodynamic effects utilizing the PAC. Once therapies that are effective in improving outcomes are available, the PAC might be a useful or necessary tool in the initiation and titration of such treatments and improved outcomes from PAC guided therapy may be demonstrated. Adequate training and experience are required to successfully use the PAC to minimize complications, ensure proper data collection and appropriate decision-making. Improved education and guidelines are required to ensure continued safe and appropriate contemporary use of the PAC.

Pulmonary artery catheters for adult patients in intensive care.

BACKGROUND: Since pulmonary artery balloon flotation catheterization was first introduced in 1970, by HJ Swan and W Ganz, it has been widely disseminated as a diagnostic tool without rigorous evaluation of its clinical utility and effectiveness in critically ill patients. A pulmonary artery catheter (PAC) is inserted through a central venous access into the right side of the heart and floated into the pulmonary artery. PAC is used to measure stroke volume, cardiac output, mixed venous oxygen saturation and intracardiac pressures with a variety of additional calculated variables to guide diagnosis and treatment. Complications of the procedure are mainly related to line insertion. Relatively uncommon complications include cardiac arrhythmias, pulmonary haemorrhage and infarct, and associated mortality from balloon tip rupture. OBJECTIVES: To provide an up-to-date assessment of the effectiveness of a PAC on mortality, length of stay (LOS) in intensive care unit (ICU) and hospital and cost of care in adult intensive care patients. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 12); MEDLINE (1954 to January 2012); EMBASE (1980 to January 2012); CINAHL (1982 to January 2012), and reference lists of articles. We contacted researchers in the field. We did a grey literature search for articles published until January 2012. SELECTION CRITERIA: We included all randomized controlled trials conducted in adults ICUs, comparing management with and without a PAC. DATA COLLECTION AND ANALYSIS: We screened the titles and abstracts and then the full text reports identified from our electronic search. Two authors (SR and MG) independently reviewed the titles, abstracts and then the full text reports for inclusion. We determined the final list of included studies by discussion among the group members (SR, ND, MG, AK and SC) with consensus agreement. We included all the studies that were in the original review. We assessed seven domains of potential risk of bias for the included studies. We examined the clinical, methodological and statistical heterogeneity and used random-effects model for meta-analysis. We calculated risk ratio for mortality across studies and mean days for LOS. MAIN RESULTS: We included 13 studies (5686 patients). We judged blinding of participants and personnel and blinding of outcome assessment to be at high risk in about 50% of the included studies and at low risk in 25% to 30% of the studies. Regardless of the high risk of performance bias these studies were included based on the low weight the studies had in the meta-analysis. We rated 75% of the studies as low risk for selection, attrition and reporting bias. All 13 studies reported some type of hospital mortality (28-day, 30-day, 60-day or ICU mortality). We considered studies of high-risk surgery patients (eight studies) and general intensive care patients (five studies) separately as subgroups for meta-analysis. The pooled risk ratio (RR) for mortality for the studies of general intensive care patients was 1.02 (95% confidence interval (CI) 0.96 to 1.09) and for the studies of high-risk surgery patients the RR was 0.98 (95% CI 0.74 to 1.29). Of the eight studies of high-risk surgery patients, five evaluated the effectiveness of pre-operative optimization but there was no difference in mortality when these studies were examined separately. PAC did not affect general ICU LOS (reported by four studies) or hospital LOS (reported by nine studies). Four studies, conducted in the United States (US), reported costs based on hospital charges billed, which on average were higher in the PAC groups. Two of these studies qualified for analysis and did not show a statistically significant hospital cost difference (mean difference USD 900, 95% CI -2620 to 4420, P = 0.62). AUTHORS' CONCLUSIONS: PAC is a diagnostic and haemodynamic monitoring tool but not a therapeutic intervention. Our review concluded that use of a PAC did not alter the mortality, general ICU or hospital LOS, or cost for adult patients in intensive care. The quality of evidence was high for mortality and LOS but low for cost analysis. Efficacy studies are needed to determine if there are optimal PAC-guided management protocols, which when applied to specific patient groups in ICUs could result in benefits such as shock reversal, improved organ function and less vasopressor use. Newer, less-invasive haemodynamic monitoring tools need to be validated against PAC prior to clinical use in critically ill patients.

Assessment of cardiovascular function by combining clinical data with a computational model of the cardiovascular system.

OBJECTIVE: A sufficient understanding of patients' cardiovascular status is necessary for doctors to make the best decisions with regard to the treatment of cardiovascular disease; however, it is often not available because of the limitation of clinical measurements. The objective of this study was to examine whether cardiovascular function can be assessed quantitatively and for specific patients by combining clinical data with a computational model of the cardiovascular system. METHODS: Seven consecutive patients undergoing off-pump coronary artery bypass grafting were enrolled in this study. The clinical data were collected both during the preoperative diagnosis and during the operation. Sensitivity analysis was performed to select the major model parameters most relevant to the measured data. The major model parameters were then estimated through a data-fitting procedure, enabling a patient-specific quantitative assessment of various aspects of cardiovascular function. RESULTS: The results revealed the prevalence of left ventricular diastolic dysfunction in the patients, although the severity of dysfunction exhibits significant interpatient variability (the estimated left ventricular passive elastance varies from 194% to 540% of its reference value). Moreover, 4 of the 7 patients studied had impaired left ventricular systolic function. CONCLUSIONS: The current study demonstrates the feasibility of assessing cardiovascular function quantitatively by combining clinical data with a cardiovascular model. In particular, the assessment utilizes the measurements already in use or available in clinical settings, enhancing the clinical potential of the proposed method.

A matching method for improving covariate balance in cost-effectiveness analyses.

In cost-effectiveness analyses (CEA) that use randomized controlled trials (RCTs), covariates of prognostic importance may be imbalanced and warrant adjustment. In CEA that use non-randomized studies (NRS), the selection on observables assumption must hold for regression and matching methods to be unbiased. Even in restricted circumstances when this assumption is plausible, a key concern is how to adjust for imbalances in observed confounders. If the propensity score is misspecified, the covariates in the matched sample will be imbalanced, which can lead to conditional bias. To address covariate imbalance in CEA based on RCTs and NRS, this paper considers Genetic Matching. This matching method uses a search algorithm to directly maximize covariate balance. We compare Genetic and propensity score matching in Monte Carlo simulations and two case studies, CEA of pulmonary artery catheterization, based on an RCT and an NRS. The simulations show that Genetic Matching reduces the conditional bias and root mean squared error compared with propensity score matching. Genetic Matching achieves better covariate balance than the unadjusted analyses of the RCT data. In the NRS, Genetic Matching improves on the balance obtained from propensity score matching and gives substantively different estimates of incremental cost-effectiveness. We conclude that Genetic Matching can improve balance on measured covariates in CEA that use RCTs and NRS, but with NRS, this will be insufficient to reduce bias; the selection on observables assumption must also hold.

Venous oximetry and the assessment of oxygen transport balance.

OBJECTIVE: To review the principles of venous oximetry; the physiology of oxygen transport balance; clinical studies on venous oximetry; and the assignment of a classification of recommendation and level of evidence. DATA SOURCE: A MEDLINE-based literature source. CONCLUSION: One of the tenets of critical care medicine is to provide a timely and accurate assessment of tissue oxygenation. In conjunction with other monitoring modalities, the routine deployment of central venous catheters readily enables the clinician to complete this task.

Lack of effectiveness of the pulmonary artery catheter in cardiac surgery.

BACKGROUND: The pulmonary artery catheter (PAC) continues to be used for monitoring of hemodynamics in patients undergoing coronary artery bypass graft (CABG) surgery despite concerns raised in other settings regarding both effectiveness and safety. Given the relative paucity of data regarding its use in CABG patients, and given entrenched practice patterns, we assessed the impact of PAC use on fatal and nonfatal CABG outcomes as practiced at a diverse set of medical centers. METHODS: Using a formal prospective observational study design, 5065 CABG patients from 70 centers were enrolled between November 1996 and June 2000 using a systemic sampling protocol. Propensity score matched-pair analysis was used to adjust for differences in likelihood of PAC insertion. The predefined composite endpoint was the occurrence of any of the following: death (any cause), cardiac dysfunction (myocardial infarction or congestive heart failure), cerebral dysfunction (stroke or encephalopathy), renal dysfunction (dysfunction or failure), or pulmonary dysfunction (acute respiratory distress syndrome). Secondary variables included treatment indices (inotrope use, fluid administration), duration of postoperative intubation, and intensive care unit length of stay. After categorization based on PAC and transesophageal echocardiography use (both, neither, PAC only, transesophageal echocardiography only), we performed the primary analysis contrasting PAC only and neither (total, 3321 patients), from which propensity paring yielded 1273 matched pairs. RESULTS: The primary endpoint occurred in 271 PAC patients versus 196 without PAC (21.3% vs.15.4%; adjusted odds ratio [AOR], 1.68; 95% confidence interval [CI], 1.24 to 2.26; P<0.001). The PAC group had an increased risk of all-cause mortality, 3.5% vs 1.7% (AOR, 2.08; 95% CI, 1.11 to 3.88; P=0.02) and an increased risk of cardiac (AOR, 1.58; 95% CI, 1.14 to 2.20; P=0.007), cerebral (AOR, 2.02; 95% CI, 1.08 to 3.77; P=0.03) and renal (AOR, 2.47; 95% CI, 1.68 to 3.62; P<0.001) morbid outcomes. PAC patients received inotropic drugs more frequently (57.8% vs 50.0%; P<0.001), had a larger positive IV fluid balance after surgery (3220 mL vs 3022 mL; P=0.003), and experienced longer time to tracheal extubation (15.40 hours [11.28/20.80] versus 13.18 hours [9.58/19.33], median plus Q1/Q3 interquartile range; P<0.0001). Use of PAC was also associated with prolonged intensive care unit stay (14.5% vs 10.1%; AOR, 1.55; 95% CI, 1.06 to 2.27; P=0.02). CONCLUSIONS: Use of a PAC during CABG surgery was associated with increased mortality and a higher risk of severe end-organ complications in this propensity-matched observational study. A randomized controlled trial with defined hemodynamic goals would be ideal to either confirm or refute our findings.

The effect of pulmonary artery catheter use on costs and long-term outcomes of acute lung injury.

BACKGROUND: The pulmonary artery catheter (PAC) remains widely used in acute lung injury (ALI) despite known complications and little evidence of improved short-term mortality. Concurrent with NHLBI ARDS Clinical Trials Network Fluid and Catheters Treatment Trial (FACTT), we conducted a prospectively-defined comparison of healthcare costs and long-term outcomes for care with a PAC vs. central venous catheter (CVC). We explored if use of the PAC in ALI is justified by a beneficial cost-effectiveness profile. METHODS: We obtained detailed bills for the initial hospitalization. We interviewed survivors using the Health Utilities Index Mark 2 questionnaire at 2, 6, 9 and 12 m to determine quality of life (QOL) and post-discharge resource use. Outcomes beyond 12 m were estimated from federal databases. Incremental costs and outcomes were generated using MonteCarlo simulation. RESULTS: Of 1001 subjects enrolled in FACTT, 774 (86%) were eligible for long-term follow-up and 655 (85%) consented. Hospital costs were similar for the PAC and CVC groups ($96.8k vs. $89.2k, p = 0.38). Post-discharge to 12 m costs were higher for PAC subjects ($61.1k vs. 45.4k, p = 0.03). One-year mortality and QOL among survivors were similar in PAC and CVC groups (mortality: 35.6% vs. 31.9%, p = 0.33; QOL [scale: 0-1]: 0.61 vs. 0.66, p = 0.49). MonteCarlo simulation showed PAC use had a 75.2% probability of being more expensive and less effective (mean cost increase of $14.4k and mean loss of 0.3 quality-adjusted life years (QALYs)) and a 94.2% probability of being higher than the $100k/QALY willingness-to-pay threshold. CONCLUSION: PAC use increased costs with no patient benefit and thus appears unjustified for routine use in ALI. TRIAL REGISTRATION: www.clinicaltrials.gov NCT00234767.

[Assessment of cardiac output and intrathoracic blood volume by means of transpulmonary thermodilution and ultrasound dilution: similarities and differences].

UNLABELLED: The aim of the study is to compare results of the assessment of cardiac output and intrathoracic blood volume by two methods--transpulmonary (TTD) and ultrasound (UTD) thermodilution. MATERIALS AND METHODS: The prospective study included 58 patients (sepsis, septic shock, acute respiratory distress syndrome, intracranial haemorrhages), which underwent femoral artery catheterization with "Pulsiocath" 5Fr catheter (PICCO technology). For the means of ultrasound the catheter was connected to the central venous catheter by an arteriovenous loop. Sensors on arterial and venous ends of the loop registered the time and the volume of the indicator, blood properties and the ultrasound curve. Cooled (0 to 8 C) 5% glucose solution was used as an indicator for TTD, while heated (up to 37C) 0.9% NaCl solution was used as an indicator for the ultrasound. The cardiac output (CO) was measured by TTD and UTD, the global end diastolic volume (GEDV) by TTD, its analogue total end diastolic volume (TEDV) by UTD, intrathoracic blood volume (ITBV) by TTD and central blood volume (CBV) by UTD. 218 pairs of measurements were conducted. Oscillations of CO (TTD) were 2.76-16.3 l/min (8.6 +/- 2.48 l/min) and of CO (UTD)--2.92-18.1 l/min (8.72 +/- 2.65 l/min). There was a strong correlation between CO (TTD) and CO (UTD). The systematic mistake was 0.12 l/min, percentage based mistake--20.9%. ITBV correlated with CBV. There was a big systematic mistake found, which measured as much as 323 ml, the percentage based mistake was 36.5%. The correlation between GEDV and TEDV was (r = 0.70, p < 0.01). The TTD ejection fraction (23.2 +/- 5.6%) was lower (p < 0.01), than by UTD (57.8 +/- 15.2%). RESULTS: Both methods demonstrate close values of CO. GEDV was higher than TEDV and physiological heart volume. The absolute values of GEDV and ITBV measured by TTD are higher than the actual ones, although they reflect the changes of blood volume and can be used as dynamic preload parameters.