B-Lines for the assessment of extravascular lung water: Just focused or semi-quantitative?

BACKGROUND: B-lines as typical artefacts of lung ultrasound are considered as surrogate measurement for extravascular lung water. However, B-lines develop in the sub-pleural space and do not allow assessment of the whole lung. Here, we present data from the first observational multi-centre study focusing on the correlation between a B-lines score and extravascular lung water in critically ill patients suffering from a variety of diseases. PATIENTS AND METHODS: In 184 adult patients, 443 measurements were obtained. B-lines were counted and expressed in a score which was compared to extravascular lung water, measured by single-indicator transpulmonary thermodilution. Appropriate correlation coefficients were calculated and receiver operating characteristics (ROC-) curves were plotted. RESULTS: Overall, B-lines score was correlated with body weight-indexed extravascular lung water characterized by r = .59. The subgroup analysis revealed a correlation coefficient in patients without an infection of r = .44, in those with a pulmonary infection of r = .75 and in those with an abdominal infection of r = .23, respectively. Using ROC-analysis the sensitivity and specificity of B-lines for detecting an increased extravascular lung water (>10 mL/kg) was 63% and 79%, respectively. In patients with a P/F ratio <200 mm Hg, sensitivity and specificity to predict an increased extravascular lung water was 71% and 93%, respectively. CONCLUSIONS: Assessment of B-lines does not accurately reflect actual extravascular lung water. In presence of an impaired oxygenation, B-lines may reliably indicate increased extravascular lung water as cause of the oxygenation disorders.

Cost-effectiveness-analysis of ultrasound guidance for central venous catheterization compared with landmark method: a decision-analytic model.

BACKGROUND: Ultrasound guidance for central venous catheterization is a commonly used alternative to the conventional landmark method. Because from the German perspective, the cost-effectiveness of ultrasound guidance is unclear, this study examined the cost-effectiveness of ultrasound guidance versus the landmark method for adults undergoing a central venous catheterization. METHODS: A decision-tree based model was built to estimate the costs of averted catheter-related complications. Clinical data (e.g. arterial puncture, failed attempts) were obtained from a Cochrane review and a randomized controlled trial, whilst information about cost parameters were taken from a German hospital of maximum care. The analysis was conducted from the perspective of the German Statutory Health Insurance. Results were presented as incremental cost-effectiveness ratios. To assess the parameter uncertainty, several sensitivity analyses were performed (deterministic, probabilistic and with regard to the model structure). RESULTS: Our analysis revealed that ultrasound guidance resulted in fewer complications per person (0.04 versus 0.17 for the landmark method) and was less expensive (€51 versus €230 for the landmark method). Results were robust to changes in the model parameters and in the model structure. Whilst our model population reflected approximately 49% of adults undergoing a central venous catheterization cannulation per year, structural sensitivity analyses (e.g. extending the study cohort to patients at higher baseline risk of complications, pediatric patients, or using real-time/indirect catheterization) indicated the cost-effectiveness of ultrasound guidance for a broader spectrum of patients. The results should be interpreted by considering the assumptions (e.g. target population) and approximations (e.g. cost parameters) underpinning the model. CONCLUSIONS: Ultrasound guidance for central venous catheterization averts more catheter-related complications and may save the resources of the German Statutory Health Insurance compared with landmark method.

Percutaneous techniques versus surgical techniques for tracheostomy.

BACKGROUND: Tracheostomy formation is one of the most commonly performed surgical procedures in critically ill intensive care participants requiring long-term mechanical ventilation. Both surgical tracheostomies (STs) and percutaneous tracheostomies (PTs) are used in current surgical practice; but until now, the optimal method of performing tracheostomies in critically ill participants remains unclear. OBJECTIVES: We evaluated the effectiveness and safety of percutaneous techniques compared to surgical techniques commonly used for elective tracheostomy in critically ill participants (adults and children) to assess whether there was a difference in complication rates between the procedures. We also assessed whether the effect varied between different groups of participants or settings (intensive care unit (ICU), operating room), different levels of operator experience, different percutaneous techniques, or whether the percutaneous techniques were carried out with or without bronchoscopic guidance. SEARCH METHODS: We searched the following electronic databases: CENTRAL, MEDLINE, EMBASE, and CINAHL to 28 May 2015. We also searched reference lists of articles, 'grey literature', and dissertations. We handsearched intensive care and anaesthesia journals, abstracts, and proceedings of scientific meetings. We attempted to identify unpublished or ongoing studies by contacting manufacturers and experts in the field, and searching in trial registers. SELECTION CRITERIA: We included randomized and quasi-randomized controlled trials (quasi-RCTs) comparing percutaneous techniques (experimental intervention) with surgical techniques (control intervention) used for elective tracheostomy in critically ill participants (adults and children). DATA COLLECTION AND ANALYSIS: Three authors independently checked eligibility and extracted data on methodological quality, participant characteristics, intervention details, settings, and outcomes of interest using a standardized form. We then entered data into Review Manager 5, with a double-entry procedure. MAIN RESULTS: Of 785 identified citations, 20 trials from 1990 to 2011 enrolling 1652 participants fulfilled the inclusion criteria. We judged most of the trials to be at low or unclear risk of bias across the six domains, and we judged four studies to have elements of high risk of bias; we did not classify any studies at overall low risk of bias. The quality of evidence was low for five of the seven outcomes (very low N = 1, moderate N = 1) and there was heterogeneity among the studies. There was a variety of adult participants and the procedures were performed by a wide range of differently experienced operators in different situations.There was no evidence of a difference in the rate of the primary outcomes: mortality directly related to the procedure (Peto odds ratio (POR) 0.52, 95% confidence interval (CI) 0.10 to 2.60, I² = 44%, P = 0.42, 4 studies, 257 participants, low quality evidence); and serious, life-threatening adverse events - intraoperatively: risk ratio (RR) 0.93, 95% CI 0.57 to 1.53, I² = 27%, P = 0.78, 12 studies, 1211 participants, low quality evidence,and direct postoperatively: RR 0.72, 95% CI 0.41 to 1.25, I² = 24%, P = 0.24, 10 studies, 984 participants, low quality evidence.PTs significantly reduce the rate of the secondary outcome, wound infection/stomatitis by 76% (RR 0.24, 95% CI 0.15 to 0.37, I² = 0%, P < 0.00001, 12 studies, 936 participants, moderate quality evidence) and the rate of unfavourable scarring by 75% (RR 0.25, 95% CI 0.07 to 0.91, I² = 86%, P = 0.04, 6 studies, 789 participants, low quality evidence). There was no evidence of a difference in the rate of the secondary outcomes, major bleeding (RR 0.70, 95% CI 0.45 to 1.09, I² = 47%, P = 0.12, 10 studies, 984 participants, very low quality evidence) and tracheostomy tube occlusion/obstruction, accidental decannulation, difficult tube change (RR 1.36, 95% CI 0.65 to 2.82, I² = 22%, P = 0.42, 6 studies, 538 participants, low quality evidence). AUTHORS' CONCLUSIONS: When compared to STs, PTs significantly reduce the rate of wound infection/stomatitis (moderate quality evidence) and the rate of unfavourable scarring (low quality evidence due to imprecision and heterogeneity). In terms of mortality and the rate of serious adverse events, there was low quality evidence that non-significant positive effects exist for PTs. In terms of the rate of major bleeding, there was very low quality evidence that non-significant positive effects exist for PTs.However, because several groups of participants were excluded from the included studies, the number of participants in the included studies was limited, long-term outcomes were not evaluated, and data on participant-relevant outcomes were either sparse or not available for each study, the results of this meta-analysis are limited and cannot be applied to all critically ill adults.

Ultrasound guidance versus anatomical landmarks for internal jugular vein catheterization.

BACKGROUND: Central venous catheters (CVCs) can help with diagnosis and treatment of the critically ill. The catheter may be placed in a large vein in the neck (internal jugular vein), upper chest (subclavian vein) or groin (femoral vein). Whilst this is beneficial overall, inserting the catheter risks arterial puncture and other complications and should be performed with as few attempts as possible. Traditionally, anatomical 'landmarks' on the body surface were used to find the correct place in which to insert catheters, but ultrasound imaging is now available. A Doppler mode is sometimes used to supplement plain 'two-dimensional' ultrasound. OBJECTIVES: The primary objective of this review was to evaluate the effectiveness and safety of two-dimensional (imaging ultrasound (US) or ultrasound Doppler (USD)) guided puncture techniques for insertion of central venous catheters via the internal jugular vein in adults and children. We assessed whether there was a difference in complication rates between traditional landmark-guided and any ultrasound-guided central vein puncture.Our secondary objectives were to assess whether the effect differs between US and USD; whether the effect differs between ultrasound used throughout the puncture ('direct') and ultrasound used only to identify and mark the vein before the start of the puncture procedure (indirect'); and whether the effect differs between different groups of patients or between different levels of experience among those inserting the catheters. SEARCH METHODS: We searched the Central Register of Controlled Trials (CENTRAL) (2013, Issue 1), MEDLINE (1966 to 15 January 2013), EMBASE (1966 to 15 January 2013), the Cumulative Index to Nursing and Allied Health Literature (CINAHL) (1982 to 15 January 2013 ), reference lists of articles, 'grey literature' and dissertations. An additional handsearch focused on intensive care and anaesthesia journals and abstracts and proceedings of scientific meetings. We attempted to identify unpublished or ongoing studies by contacting companies and experts in the field, and we searched trial registers. We reran the search in August 2014. We will deal with identified studies of interest when we update the review. SELECTION CRITERIA: We included randomized and quasi-randomized controlled trials comparing two-dimensional ultrasound or Doppler ultrasound with an anatomical 'landmark' technique during insertion of internal jugular venous catheters in both adults and children. DATA COLLECTION AND ANALYSIS: Three review authors independently extracted data on methodological quality, participants, interventions and outcomes of interest using a standardized form. A priori, we aimed to perform subgroup analyses, when possible, for adults and children, and for experienced operators and inexperienced operators. MAIN RESULTS: Of 735 identified citations, 35 studies enrolling 5108 participants fulfilled the inclusion criteria. The quality of evidence was very low for most of the outcomes and was moderate at best for four of the outcomes. Most trials had an unclear risk of bias across the six domains, and heterogeneity among the studies was significant.Use of two-dimensional ultrasound reduced the rate of total complications overall by 71% (14 trials, 2406 participants, risk ratio (RR) 0.29, 95% confidence interval (CI) 0.17 to 0.52; P value < 0.0001, I² = 57%), and the number of participants with an inadvertent arterial puncture by 72% (22 trials, 4388 participants, RR 0.28, 95% CI 0.18 to 0.44; P value < 0.00001, I² = 35%). Overall success rates were modestly increased in all groups combined at 12% (23 trials, 4340 participants, RR 1.12, 95% CI 1.08 to 1.17; P value < 0.00001, I² = 85%), and similar benefit was noted across all subgroups. The number of attempts needed for successful cannulation was decreased overall (16 trials, 3302 participants, mean difference (MD) -1.19 attempts, 95% CI -1.45 to -0.92; P value < 0.00001, I² = 96%) and in all subgroups. Use of two-dimensional ultrasound increased the chance of success at the first attempt by 57% (18 trials, 2681 participants, RR 1.57, 95% CI 1.36 to 1.82; P value < 0.00001, I² = 82%) and reduced the chance of haematoma formation (overall reduction 73%, 13 trials, 3233 participants, RR 0.27, 95% CI 0.13 to 0.55; P value 0.0004, I² = 54%). Use of two-dimensional ultrasound decreased the time to successful cannulation by 30.52 seconds (MD -30.52 seconds, 95% CI -55.21 to -5.82; P value 0.02, I² = 97%). Additional data are available to support use of ultrasound during, not simply before, line insertion.Use of Doppler ultrasound increased the chance of success at the first attempt by 58% (four trials, 199 participants, RR 1.58, 95% CI 1.02 to 2.43; P value 0.04, I² = 57%). No evidence showed a difference for the total numbers of perioperative and postoperative complications/adverse events (three trials, 93 participants, RR 0.52, 95% CI 0.16 to 1.71; P value 0.28), the overall success rate (seven trials, 289 participants, RR 1.09, 95% CI 0.95 to 1.25; P value 0.20), the total number of attempts until success (two trials, 69 participants, MD -0.63, 95% CI -1.92 to 0.66; P value 0.34), the overall number of participants with an arterial puncture (six trials, 213 participants, RR 0.61, 95% CI 0.21 to 1.73; P value 0.35) and time to successful cannulation (five trials, 214 participants, each using a different definition for this outcome; MD 62.04 seconds, 95% CI -13.47 to 137.55; P value 0.11) when Doppler ultrasound was used. It was not possible to perform analyses for the other outcomes because they were reported in only one trial. AUTHORS' CONCLUSIONS: Based on available data, we conclude that two-dimensional ultrasound offers gains in safety and quality when compared with an anatomical landmark technique. Because of missing data, we did not compare effects with experienced versus inexperienced operators for all outcomes (arterial puncture, haematoma formation, other complications, success with attempt number one), and so the relative utility of ultrasound in these groups remains unclear and no data are available on use of this technique in patients at high risk of complications. The results for Doppler ultrasound techniques versus anatomical landmark techniques are also uncertain.

Ultrasound guidance versus anatomical landmarks for subclavian or femoral vein catheterization.

BACKGROUND: Central venous catheters can help with diagnosis and treatment of the critically ill. The catheter may be placed in a large vein in the neck (internal jugular vein), upper chest (subclavian vein) or groin (femoral vein). Whilst this is beneficial overall, inserting the catheter risks arterial puncture and other complications and should be performed in as few attempts as possible.In the past, anatomical 'landmarks' on the body surface were used to find the correct place to insert these catheters, but ultrasound imaging is now available. A Doppler mode is sometimes used to supplement plain 'two-dimensional' ultrasound. OBJECTIVES: The primary objective of this review was to evaluate the effectiveness and safety of two-dimensional ultrasound (US)- or Doppler ultrasound (USD)-guided puncture techniques for subclavian vein, axillary vein and femoral vein puncture during central venous catheter insertion in adults and children. We assessed whether there was a difference in complication rates between traditional landmark-guided and any ultrasound-guided central vein puncture.When possible, we also assessed the following secondary objectives: whether a possible difference could be verified with use of the US technique versus the USD technique; whether there was a difference between using ultrasound throughout the puncture ('direct') and using it only to identify and mark the vein before starting the puncture procedure ('indirect'); and whether these possible differences might be evident in different groups of patients or with different levels of experience among those inserting the catheters. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2013, Issue 1), MEDLINE (1966 to 15 January 2013), EMBASE (1966 to 15 January 2013), the Cumulative Index to Nursing and Allied Health Literature (CINAHL) (1982 to 15 January 2013), reference lists of articles, 'grey literature' and dissertations. An additional handsearch focused on intensive care and anaesthesia journals and abstracts and proceedings of scientific meetings. We attempted to identify unpublished or ongoing studies by contacting companies and experts in the field, and we searched trial registers. We reran the search in August 2014. We will deal with any studies of interest when we update the review. SELECTION CRITERIA: Randomized and quasi-randomized controlled trials comparing two-dimensional ultrasound or Doppler ultrasound versus an anatomical 'landmark' technique during insertion of subclavian or femoral venous catheters in both adults and children. DATA COLLECTION AND ANALYSIS: Three review authors independently extracted data on methodological quality, participants, interventions and outcomes of interest using a standardized form. We performed a priori subgroup analyses. MAIN RESULTS: Altogether 13 studies enrolling 2341 participants (and involving 2360 procedures) fulfilled the inclusion criteria. The quality of evidence was very low (subclavian vein N = 3) or low (subclavian vein N = 4, femoral vein N = 2) for most outcomes, moderate for one outcome (femoral vein) and high at best for two outcomes (subclavian vein N = 1, femoral vein N = 1). Most of the trials had unclear risk of bias across the six domains, and heterogeneity among the studies was significant.For the subclavian vein (nine studies, 2030 participants, 2049 procedures), two-dimensional ultrasound reduced the risk of inadvertent arterial puncture (three trials, 498 participants, risk ratio (RR) 0.21, 95% confidence interval (CI) 0.06 to 0.82; P value 0.02, I² = 0%) and haematoma formation (three trials, 498 participants, RR 0.26, 95% CI 0.09 to 0.76; P value 0.01, I² = 0%). No evidence was found of a difference in total or other complications (together, US, USD), overall (together, US, USD), number of attempts until success (US) or first-time (US) success rates or time taken to insert the catheter (US).For the femoral vein, fewer data were available for analysis (four studies, 311 participants, 311 procedures). No evidence was found of a difference in inadvertent arterial puncture or other complications. However, success on the first attempt was more likely with ultrasound (three trials, 224 participants, RR 1.73, 95% CI 1.34 to 2.22; P value < 0.0001, I² = 31%), and a small increase in the overall success rate was noted (RR 1.11, 95% CI 1.00 to 1.23; P value 0.06, I² = 50%). No data on mortality or participant-reported outcomes were provided. AUTHORS' CONCLUSIONS: On the basis of available data, we conclude that two-dimensional ultrasound offers small gains in safety and quality when compared with an anatomical landmark technique for subclavian (arterial puncture, haematoma formation) or femoral vein (success on the first attempt) cannulation for central vein catheterization. Data on insertion by inexperienced or experienced users, or on patients at high risk for complications, are lacking. The results for Doppler ultrasound techniques versus anatomical landmark techniques are uncertain.

LIFEBRIDGE: a portable, modular, rapidly available "plug-and-play" mechanical circulatory support system.

PURPOSE: We describe the LIFEBRIDGE, a portable, modular, rapidly available "plug-and-play" mechanical circulatory support system, and report its experimental safety evaluation. DESCRIPTION: The modular construction consists of a disposable patient module with cardiopulmonary bypass circuit, control module, and base module with power supply, embedded PC, and user interface. The system weighs about 20 kg, has a modular design, and has semi-automatic priming that allows action within 5 minutes, and a 7-step air elimination program that prevents air embolization. EVALUATION: In eight pigs (85 +/- 10 kg) we investigated this system using central (right atrium and ascending aorta) cannulation (n = 4) or peripheral (iliac) cannulation (n = 4). Pump flows were 5.7 +/- 0.2 L/min with central and 4.1 +/- 0.2 L/min with peripheral cannulation, yielding sufficient animal perfusion and gas exchange. Using an intraaortic 8-MHz Doppler device, we demonstrated that venous air boluses of up to 100 mL were effectively removed, thus avoiding air embolization. Changing heights between animals and LIFEBRIDGE did not affect its proper action. CONCLUSIONS: This initial evaluation demonstrates that the LIFEBRIDGE is rapidly available, provides adequate perfusion and gas exchange, and operates safely even under simulated transport conditions.