An evaluation of the clinical and cost-effectiveness of pulmonary artery catheters in patient management in intensive care: a systematic review and a randomised controlled trial

The effects of static and dynamic measurements using transpulmonary thermodilution devices on fluid therapy in septic shock: A systematic review

Transpulmonary thermodilution devices have been widely shown to be accurate in septic shock patients in assessing fluid responsiveness. We conducted a systematic review to assess the relationship between fluid therapy protocols guided by transpulmonary thermodilution devices on fluid balance and the amount of intravenous fluid used in septic shock. We searched MEDLINE, Embase and The Cochrane Library. Studies were eligible for inclusion if they were prospective, parallel trials that were conducted in an intensive care setting in patients with septic shock. The comparator group was either central venous pressure, early goal-directed therapy or pulmonary artery occlusion pressure. Studies assessing only the accuracy of fluid responsiveness prediction by transpulmonary thermodilution devices were excluded. Two reviewers independently performed the search, extracted data and assessed the bias of each study. In total 27 full-text articles were identified for eligibility; of these, nine studies were identified for inclusion in the systematic review. Three of these trials used dynamic parameters derived from transpulmonary thermodilution devices and six used primarily static parameters to guide fluid therapy. There was evidence for a significant reduction in positive fluid balance in four out of the nine studies. From the available studies, the results suggest the benefit of transpulmonary thermodilution monitoring in the septic shock population with regard to reducing positive fluid balance is seen when the devices are utilised for at least 72 hours. Both dynamic and static parameters derived from transpulmonary thermodilution devices appear to lead to a reduction in positive fluid balance in septic shock patients compared to measurements of central venous pressure and early goal-directed therapy.

Perforation of the left ventricle wall due to the insertion of a pulmonary artery catheter. A case report

Despite the widespread and frequent use in our setting of pulmonary artery catheters for haemodynamic management in critically ill patients, particularly after heart surgery, some experts continue to question the need for these devices. Clinicians need to weigh up the risks and benefits of pulmonary artery catheters placement and bear in mind the potential complications which, though rare, can be potentially fatal. We present a pulmonary artery catheters-related complication not hitherto described in the literature, involving perforation of the interventricular septum and left ventricular free wall caused by a kink in the pulmonary artery catheters that was not suspected, and only diagnosed by direct vision of the heart after pericardial opening. In the interest of patient safety, we must consider the impact of adverse events; improving our situational awareness and our understanding of the mechanisms behind such events can help reduce the likelihood of repetitions in the future.

Test-Retest Reliability of Non-Invasive Cardiac Output Measurement during Exercise in Healthy Volunteers in Daily Clinical Routine

Background

Thoracic bioreactance (TB), a noninvasive method for the measurement of cardiac output (CO), shows good test-retest reliability in healthy adults examined under research and resting conditions.

Objective

In this study, we evaluate the test-retest reliability of CO and cardiac power (CPO) output assessment during exercise assessed by TB in healthy adults under routine clinical conditions.

Methods

25 test persons performed a symptom-limited graded cycling test in an outpatient office on two different days separated by one week. Cardiorespiratory (power output, VO_2peak) and hemodynamic parameters (heart rate, stroke volume, CO, mean arterial pressure, CPO) were measured at rest and continuously under exercise using a spiroergometric system and bioreactance cardiograph (NICOM, Cheetah Medical).

Results

After 8 participants were excluded due to measurement errors (outliers), there was no systematic bias in all parameters under all conditions (effect size: 0.2-0.6). We found that all noninvasively measured CO showed acceptable test-retest-reliability (intraclass correlation coefficient: 0.59-0.98; typical error: 0.3-1.8). Moreover, peak CPO showed better reliability (intraclass correlation coefficient: 0.80-0.85; effect size: 0.9-1.1) then the TB CO, thanks only to the superior reliability of MAP (intraclass correlation coefficient: 0.59-0.98; effect size: 0.3-1.8).

Conclusion

Our findings preclude the clinical use of TB in healthy subject population when outliers are not identified.

Passive Self Resonant Skin Patch Sensor to Monitor Cardiac Intraventricular Stroke Volume Using Electromagnetic Properties of Blood

This paper focuses on the development of a passive, lightweight skin patch sensor that can measure fluid volume changes in the heart in a non-invasive, point-of-care setting. The wearable sensor is an electromagnetic, self-resonant sensor configured into a specific pattern to formulate its three passive elements (resistance, capacitance, and inductance). In an animal model, a bladder was inserted into the left ventricle (LV) of a bovine heart, and fluid was injected using a syringe to simulate stoke volume (SV). In a human study, to assess the dynamic fluid volume changes of the heart in real time, the sensor frequency response was obtained from a participant in a 30° head-up tilt (HUT), 10° HUT, supine, and 10° head-down tilt positions over time. In the animal model, an 80-mL fluid volume change in the LV resulted in a downward frequency shift of 80.16 kHz. In the human study, there was a patterned frequency shift over time which correlated with ventricular volume changes in the heart during the cardiac cycle. Statistical analysis showed a linear correlation \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} }{}${R} ^{2} = 0.98$ \end{document} and 0.87 between the frequency shifts and fluid volume changes in the LV of the bovine heart and human participant, respectively. In addition, the patch sensor detected heart rate in a continuous manner with a 0.179% relative error compared to electrocardiography. These results provide promising data regarding the ability of the patch sensor to be a potential technology for SV monitoring in a non-invasive, continuous, and non-clinical setting.

Miniaturized Echocardiography in the Cardiac Intensive Care Unit

Miniaturized transesophageal echocardiography has become more common in cardiac intensive care units. There are potential benefits to this mode of technology, many of which have been described in the literature. However, image acquisition and quality have been cited as being less optimal when compared to traditional transesophageal echocardiography. This review will discuss the current options available for miniaturized transesophageal echocardiography along with a literature review of this emerging assessment modality.

Design and Simulation of an Integrated Wireless Capacitive Sensors Array for Measuring Ventricular Pressure

This paper reports the novel design of a touch mode capacitive pressure sensor (TMCPS) system with a wireless approach for a full-range continuous monitoring of ventricular pressure. The system consists of two modules: an implantable set and an external reading device. The implantable set, restricted to a 2 × 2 cm² area, consists of a TMCPS array connected with a dual-layer coil, for making a reliable resonant circuit for communication with the external device. The capacitive array is modelled considering the small deflection regime for achieving a dynamic and full 5⁻300 mmHg pressure range. In this design, the two inductive-coupled modules are calculated considering proper electromagnetic alignment, based on two planar coils and considering the following: 13.56 MHz frequency to avoid tissue damage and three types of biological tissue as core (skin, fat and muscle). The system was validated with the Comsol Multiphysics and CoventorWare softwares; showing a 90% power transmission efficiency at a 3.5 cm distance between coils. The implantable module includes aluminum- and polyimide-based devices, which allows ergonomic, robust, reproducible, and technologically feasible integrated sensors. In addition, the module shows a simplified and low cost design approach based on PolyMEMS INAOE^® technology, featured by low-temperature processing.

A randomised controlled trial and cost-effectiveness analysis of high-frequency oscillatory ventilation against conventional artificial ventilation for adults with acute respiratory distress syndrome. The OSCAR (OSCillation in ARDS) study

BACKGROUND

Patients with the acute respiratory distress syndrome (ARDS) require artificial ventilation but this treatment may produce secondary lung damage. High-frequency oscillatory ventilation (HFOV) may reduce this damage.

OBJECTIVES

To determine the clinical benefit and cost-effectiveness of HFOV in patients with ARDS compared with standard mechanical ventilation.

DESIGN

A parallel, randomised, unblinded clinical trial.

SETTING

UK intensive care units.

PARTICIPANTS

Mechanically ventilated patients with a partial pressure of oxygen in arterial blood/fractional concentration of inspired oxygen (P : F) ratio of 26.7 kPa (200 mmHg) or less and an expected duration of ventilation of at least 2 days at recruitment.

INTERVENTIONS

Treatment arm HFOV using a Novalung R100(®) ventilator (Metran Co. Ltd, Saitama, Japan) ventilator until the start of weaning. Control arm Conventional mechanical ventilation using the devices available in the participating centres.

MAIN OUTCOME MEASURES

The primary clinical outcome was all-cause mortality at 30 days after randomisation. The primary health economic outcome was the cost per quality-adjusted life-year (QALY) gained.

RESULTS

One hundred and sixty-six of 398 patients (41.7%) randomised to the HFOV group and 163 of 397 patients (41.1%) randomised to the conventional mechanical ventilation group died within 30 days of randomisation (p = 0.85), for an absolute difference of 0.6% [95% confidence interval (CI) -6.1% to 7.5%]. After adjustment for study centre, sex, Acute Physiology and Chronic Health Evaluation II score, and the initial P : F ratio, the odds ratio for survival in the conventional ventilation group was 1.03 (95% CI 0.75 to 1.40; p = 0.87 logistic regression). Survival analysis showed no difference in the probability of survival up to 12 months after randomisation. The average QALY at 1 year in the HFOV group was 0.302 compared to 0.246. This gives an incremental cost-effectiveness ratio (ICER) for the cost to society per QALY of £88,790 and an ICER for the cost to the NHS per QALY of £ 78,260.

CONCLUSIONS

The use of HFOV had no effect on 30-day mortality in adult patients undergoing mechanical ventilation for ARDS and no economic advantage. We suggest that further research into avoiding ventilator-induced lung injury should concentrate on ventilatory strategies other than HFOV.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN10416500.

Noninvasive measurement of cardiac stroke volume using pulse wave velocity and aortic dimensions: a simulation study

Background

Concerns about the cost-effectiveness of invasive hemodynamic monitoring in critically ill patients using pulmonary artery catheters motivate a renewed search for effective noninvasive methods to measure stroke volume. This paper explores a new approach based on noninvasively measured pulse wave velocity, pulse contour, and ultrasonically determined aortic cross sectional area.

Methods

The Bramwell-Hill equation relating pulse wave velocity to aortic compliance is applied. At the time point on the noninvasively measured pulse contour, denoted t_h, when pulse amplitude has fallen midway between systolic and diastolic values, the portion of stroke volume remaining in the aorta, and in turn the entire stroke volume, can be estimated from the compliance and the pulse waveform. This approach is tested and refined using a numerical model of the systemic circulation including the effects of blood inertia, nonlinear compliance, aortic tapering, varying heart rate, and varying myocardial contractility, in which noninvasively estimated stroke volumes were compared with known stroke volumes in the model.

Results

The Bramwell-Hill approach correctly allows accurate calculation of known, constant aortic compliance in the numerical model. When nonlinear compliance is present the proposed noninvasive technique overestimates true aortic compliance when pulse pressure is large. However, a reasonable correction for nonlinearity can be derived and applied to restore accuracy for normal and for fast heart rates (correlation coefficient > 0.98).

Conclusions

Accurate estimates of cardiac stroke volume based on pulse wave velocity are theoretically possible and feasible. The precision of the method may be less than desired, owing to the dependence of the final result on the square of measured pulse wave velocity and the first power of ultrasonically measured aortic cross sectional area. However, classical formulas for propagation of random errors suggest that the method may still have sufficient precision for clinical applications. It remains as a challenge for experimentalists to explore further the potential of noninvasive measurement of stroke volume using pulse wave velocity. The technique is non-proprietary and open access in full detail, allowing future users to modify and refine the method as guided by practical experience.

Haemodynamic monitoring in the intensive care unit: results from a web-based Swiss survey

Background. The aim of this survey was to describe, in a situation of growing availability of monitoring devices and parameters, the practices in haemodynamic monitoring at the bedside. Methods. We conducted a Web-based survey in Swiss adult ICUs (2009-2010). The questionnaire explored the kind of monitoring used and how the fluid management was addressed. Results. Our survey included 71% of Swiss ICUs. Echocardiography (95%), pulmonary artery catheter (PAC: 85%), and transpulmonary thermodilution (TPTD) (82%) were the most commonly used. TPTD and PAC were frequently both available, although TPTD was the preferred technique. Echocardiography was widely available (95%) but seems to be rarely performed by intensivists themselves. Guidelines for the management of fluid infusion were available in 45% of ICUs. For the prediction of fluid responsiveness, intensivists rely preferentially on dynamic indices or echocardiographic parameters, but static parameters, such as central venous pressure or pulmonary artery occlusion pressure, were still used. Conclusions. In most Swiss ICUs, multiple haemodynamic monitoring devices are available, although TPTD is most commonly used. Despite the usefulness of echocardiography and its large availability, it is not widely performed by Swiss intensivists themselves. Regarding fluid management, several parameters are used without a clear consensus for the optimal method.

Cardiac complications associated with goal-directed therapy in high-risk surgical patients: a meta-analysis

Patients with limited cardiopulmonary reserve are at risk of mortality and morbidity after major surgery. Augmentation of oxygen delivery index (DO2I) with i.v. fluids and inotropes (goal-directed therapy, GDT) has been shown to reduce postoperative mortality and morbidity in high-risk patients. Concerns regarding cardiac complications associated with fluid challenges and inotropes may prevent clinicians from performing GDT in patients who need it most. We hypothesized that GDT is not associated with an increased risk of cardiac complications in high-risk, non-cardiac surgical patients. We performed a systematic search of Medline, Embase, and CENTRAL databases for randomized controlled trials (RCTs) of GDT in high-risk surgical patients. Studies including cardiac surgery, trauma, and paediatric surgery were excluded. We reviewed the rates of all cardiac complications, arrhythmias, myocardial ischaemia, and acute pulmonary oedema. Meta-analyses were performed using RevMan software. Data are presented as odds ratios (ORs), [95% confidence intervals (CIs)], and P-values. Twenty-two RCTs including 2129 patients reported cardiac complications. GDT was associated with a reduction in total cardiovascular (CVS) complications [OR=0.54, (0.38-0.76), P=0.0005] and arrhythmias [OR=0.54, (0.35-0.85), P=0.007]. GDT was not associated with an increase in acute pulmonary oedema [OR=0.69, (0.43-1.10), P=0.12] or myocardial ischaemia [OR=0.70, (0.38-1.28), P=0.25]. Subgroup analysis revealed the benefit is most pronounced in patients receiving fluid and inotrope therapy to achieve a supranormal DO2I, with the use of minimally invasive cardiac output monitors. Treatment of high-risk surgical patients GDT is not associated with an increased risk of cardiac complications; GDT with fluids and inotropes to optimize DO2I during early GDT reduces postoperative CVS complications.

Clinical review: Goal-directed therapy-what is the evidence in surgical patients? The effect on different risk groups

Patients with limited cardiac reserve are less likely to survive and develop more complications following major surgery. By augmenting oxygen delivery index (DO₂I) with a combination of intravenous fluids and inotropes (goal directed therapy (GDT)), postoperative mortality and morbidity of high-risk patients may be reduced. However, although most studies suggest that GDT may improve outcome in high-risk surgical patients, it is still not widely practiced. We set out to test the hypothesis that GDT results in greatest benefit in terms of mortality and morbidity in patients with the highest risk of mortality and have undertaken a systematic review of the current literature to see if this is correct. We performed a systematic search of Medline, Embase and CENTRAL databases for randomized controlled trials (RCTs) and reviews of GDT in surgical patients. To minimize heterogeneity we excluded studies involving cardiac, trauma, and paediatric surgery. Extremely high risk, high risk and intermediate risks of mortality were defined as >20%, 5 to 20% and <5% mortality rates in the control arms of the trials, respectively. Meta analyses were performed and Forest plots drawn using RevMan software. Data are presented as odd ratios (OR; 95% confidence intervals (CI), and P-values). A total of 32 RCTs including 2,808 patients were reviewed. All studies reported mortality. Five studies (including 300 patients) were excluded from assessment of complication rates as the number of patients with complications was not reported. The mortality benefit of GDT was confined to the extremely high-risk group (OR = 0.20, 95% CI 0.09 to 0.41; P < 0.0001). Complication rates were reduced in all subgroups (OR = 0.45, 95% CI 0.34 to 0.60; P < 0.00001). The morbidity benefit was greatest amongst patients in the extremely high-risk subgroup (OR = 0.27, 95% CI 0.15 to 0.51; P < 0.0001), followed by the intermediate risk subgroup (OR = 0.43, 95% CI 0.27 to 0.67; P = 0.0002), and the high-risk subgroup (OR 0.56, 95% CI 0.36 to 0.89; P = 0.01). Despite heterogeneity in trial quality and design, we found GDT to be beneficial in all high-risk patients undergoing major surgery. The mortality benefit of GDT was confined to the subgroup of patients at extremely high risk of death. The reduction of complication rates was seen across all subgroups of GDT patients.

Use of inotropes and vasopressor agents in critically ill patients

Inotropes and vasopressors are biologically and clinically important compounds that originate from different pharmacological groups and act at some of the most fundamental receptor and signal transduction systems in the body. More than 20 such agents are in common clinical use, yet few reviews of their pharmacology exist outside of physiology and pharmacology textbooks. Despite widespread use in critically ill patients, understanding of the clinical effects of these drugs in pathological states is poor. The purpose of this article is to describe the pharmacology and clinical applications of inotropic and vasopressor agents in critically ill patients.

Clinical validation of a new thermodilution system for the assessment of cardiac output and volumetric parameters

INTRODUCTION

Transpulmonary thermodilution is used to measure cardiac output (CO), global end-diastolic volume (GEDV) and extravascular lung water (EVLW). A system has been introduced (VolumeView/EV1000™ system, Edwards Lifesciences, Irvine CA, USA) that employs a novel algorithm for the mathematical analysis of the thermodilution curve. Our aim was to evaluate the agreement of this method with the established PiCCO™ method (Pulsion Medical Systems SE, Munich, Germany, clinicaltrials.gov identifier: NCT01405040) METHODS: Seventy-two critically ill patients with clinical indication for advanced hemodynamic monitoring were included in this prospective, multicenter, observational study. During a 72-hour observation period, 443 sets of thermodilution measurements were performed with the new system. These measurements were electronically recorded, converted into an analog resistance signal and then re-analyzed by a PiCCO2™ device (Pulsion Medical Systems SE).

RESULTS

For CO, GEDV, and EVLW, the systems showed a high correlation (r(2) = 0.981, 0.926 and 0.971, respectively), minimal bias (0.2 L/minute, 29.4 ml and 36.8 ml), and a low percentage error (9.7%, 11.5% and 12.2%). Changes in CO, GEDV and EVLW were tracked with a high concordance between the two systems, with a traditional concordance for CO, GEDV, and EVLW of 98.5%, 95.1%, and 97.7% and a polar plot concordance of 100%, 99.8% and 99.8% for CO, GEDV, and EVLW, respectively. Radial limits of agreement for CO, GEDV and EVLW were 0.31 ml/minute, 81 ml and 40 ml, respectively. The precision of GEDV measurements was significantly better using the VolumeView™ algorithm compared to the PiCCO™ algorithm (0.033 (0.03) versus 0.040 (0.03; median (interquartile range), P = 0.000049).

CONCLUSIONS

For CO, GEDV, and EVLW, the agreement of both the individual measurements as well as measurements of change showed the interchangeability of the two methods. For the VolumeView method, the higher precision may indicate a more robust GEDV algorithm.

TRIAL REGISTRATION

clinicaltrials.gov NCT01405040.

Optimizing cost-effectiveness in perioperative care for liver transplantation: a model for low- to medium-income countries

Although liver transplantation (LT) is a highly effective treatment, it has been considered too costly for publicly funded health systems in many countries with low to medium average incomes. However, with economic growth and improving results, some governments are reconsidering this position. Cost-effectiveness data for LT are limited, especially in perioperative care, and the techniques and costs vary widely between centers without overt differences in outcomes. Anesthesiologists working in new programs find it difficult to determine which modalities are essential, which are needed only in exceptional circumstances, and which may be omitted without effects on outcomes. We investigated key elements of preoperative evaluations, intraoperative management, and early postoperative care that might significantly affect costs in order to develop a best-value approach for new programs in resource-limited health systems. We identified all modalities of care commonly used in anesthesia and perioperative care for adult LT along with their costs. Those considered to be universally accepted as minimum requirements for safe care were excluded from the analysis, and so were those considered to be safe and low-cost, even when evidence of efficacy was lacking. The remaining items were, therefore, those with uncertain or context-restricted value and significant costs. A systematic review of the published evidence, practice surveys, and institutional guidelines was performed, and the evidence was graded and summarized. With respect to costs and benefits, each modality was then cited as strongly recommended, recommended or optional, or no recommendation was made because of insufficient evidence. Sixteen modalities, which included preoperative cardiovascular imaging, venovenous bypass, pulmonary artery catheterization, high-flow fluid warming devices, drug therapies for hemostasis, albumin, cell salvage, anesthetic drugs, personnel (staffing) requirements, and early extubation, were assessed. Only high-flow fluid warming was strongly recommended. The recommended modalities included preoperative echocardiography, cell salvage, tranexamic acid and early extubation. Six others were rated optional, and there was insufficient evidence for 5 modalities. We conclude that some costly techniques and treatments can be omitted without adverse effects on outcomes.

Esophageal Doppler monitoring during colorectal resection offers cost-effective improvement of hemodynamic control

OBJECTIVES

Hemodynamic control can improve the outcome of surgery. Esophageal Doppler monitoring measures blood flow by ultrasound waves. This work investigates the cost-effectiveness of this procedure during colorectal resection.

METHODS

Meta-analyses of randomized controlled trials of esophageal Doppler monitoring used in colorectal resection were conducted to help determine its cost-effectiveness. An analytical decision model was used to compare the cost-effectiveness of strategies involving conventional clinical assessment with or without the measurement of central venous pressure, with or without esophageal Doppler monitoring. Avoided mortality and avoided major complications were used as measures of clinical effectiveness.

RESULTS

In the meta-analyses comparing conventional clinical assessment plus central venous pressure monitoring with or without esophageal Doppler monitoring, statistically significant differences in total and major complications favoring the use of Doppler were found. No differences were seen in mortality. The use of esophageal Doppler monitoring was associated with lower costs, mainly due to fewer complications, shorter hospital stays and shorter surgery times.

CONCLUSIONS

Although the information regarding the clinical effectiveness of esophageal Doppler monitoring in colorectal resection is limited, strategies including this form of blood flow monitoring may be cost-effective. Further comparisons of Doppler monitoring against other hemodynamic monitoring systems should be undertaken.

Monitoring in pediatric cardiac critical care: a worldwide perspective

Our ability to directly monitor the mechanisms that govern cellular function, oxygen use, and survival is minimal. Therefore, in critically ill children, surrogate markers are used to try to detect evolving or established hypoxia. These surrogate markers are best used in combination and are complementary to clinical examination. Regardless of resource limitations, we propose that the availability of certain monitoring tools form a standard of care without which pediatric cardiac critical care cannot be safely or optimally provided. These tools include standard invasive hemodynamic monitoring with electrocardiography, lactate measurement, central venous oxygen saturation, and echocardiography. Ultimately, monitoring is only useful when the clinician observes a specific value or trend and has the expertise to act appropriately.

A systematic review of models to predict recruitment to multicentre clinical trials

Background

Less than one third of publicly funded trials managed to recruit according to their original plan often resulting in request for additional funding and/or time extensions. The aim was to identify models which might be useful to a major public funder of randomised controlled trials when estimating likely time requirements for recruiting trial participants. The requirements of a useful model were identified as usability, based on experience, able to reflect time trends, accounting for centre recruitment and contribution to a commissioning decision.

Methods

A systematic review of English language articles using MEDLINE and EMBASE. Search terms included: randomised controlled trial, patient, accrual, predict, enrol, models, statistical; Bayes Theorem; Decision Theory; Monte Carlo Method and Poisson. Only studies discussing prediction of recruitment to trials using a modelling approach were included. Information was extracted from articles by one author, and checked by a second, using a pre-defined form.

Results

Out of 326 identified abstracts, only 8 met all the inclusion criteria. Of these 8 studies examined, there are five major classes of model discussed: the unconditional model, the conditional model, the Poisson model, Bayesian models and Monte Carlo simulation of Markov models. None of these meet all the pre-identified needs of the funder.

Conclusions

To meet the needs of a number of research programmes, a new model is required as a matter of importance. Any model chosen should be validated against both retrospective and prospective data, to ensure the predictions it gives are superior to those currently used.

Focused transthoracic echocardiography

Caring for critically ill patients requires rapid and accurate diagnosis followed by prompt interventions. The physical examination remains an important part of the assessment of such patients, but it has been shown to have a low sensitivity and specificity in judging left ventricular function and intravascular volume. Invasive hemodynamic monitoring has similarly been shown to have significant limitations and has failed to demonstrate a mortality benefit in several recent studies. In some studies, it has been shown to be harmful. Focused transthoracic echocardiography (TTE) has emerged as a noninvasive and portable imaging technique that is capable of providing rapid and accurate information about the heart at the bedside. It can be used to complement the physical examination and result in marked improvement in diagnostic accuracy. Focused TTE can be used as a screening and monitoring tool. Studies have shown that clinicians can be trained to determine left ventricular function, detect pericardial effusions, predict intravenous fluid responsiveness, and identify important valvular defects in a relatively short period. This article describes the indications for focused TTE, provides evidence that clinicians can be rapidly taught the technique, reviews how the focused studies affect management, and discusses the advantages and limitations of this tool.

Choosing patient-tailored hemodynamic monitoring

This article is one of ten reviews selected from the Yearbook of Intensive Care and Emergency Medicine 2010 (Springer Verlag) and co-published as a series in Critical Care. Other articles in the series can be found online at http://ccforum.com/series/yearbook. Further information about the Yearbook of Intensive Care and Emergency Medicine is available from http://www.springer.com/series/2855.

[Preliminary clinical experience with PiCCO system in children with shock]

PURPOSE

To evaluate the PiCCO hemodynamics monitor in terms of clinical usefulness in children with shock.

METHODS

Prospective multicenter analytical study in children aged from one month to 18 years with shock admitted to five pediatric intensive care units. Measurements were made before and after three interventions: a) volume load; b) increases in vasoactive drugs; c) dosage changes of drugs that could lessen vascular resistance. Recorded parameters included thermodilution data, along with the usual hemodynamic parameters.

RESULTS

A total of 120 measurements were performed on 35 patients: mean age 36 (2.6-156) months, mean weight 15 (5.8-72) kg. Shock etiology was septic in 37% of cases, cardiogenic in 26%, hypovolemic in 20% and neurogenic in 17%. No procedure related complication was noticed. Twenty-two volume challenges in 17 patients were registered. Volume load induced a significant intrathoracic blood volume index (ITBI) increase from 501(235-763) to 584 (418-810) ml/m(2), cardiac index (CI) 4.04 (2.58-6.25) to 4.48 (2.86-8.71) lmin-1m(2), and mean blood pressure from 74 (53-99) to 87 (59-112) mmHg. CI changes correlated with ITBI increase (r = 0.678, p = 0.001). 13 interventions to increase vasomotor tone were associated with an increase in contractility of 18% in systemic vascular resistance index (SVRI).

CONCLUSIONS

Hemodynamic monitoring with the PiCCO system is feasible and seems safe in children with shock. PiCCO derived parameters could add clinically important information to assess preload state and its modifications with therapy.

Pro-Con Debate: We should not Measure Cardiac output in Critical Care

The measurement of cardiac output in critical care appears to be increasingly common. However, both the monitoring technologies and the therapeutic approaches they inform have often proved highly controversial. As the range of alternative technologies available continues to increase, it seems worthwhile to question whether this monitoring modality should be used at all. The aim of this pro-con debate is to review the key evidence and to explain the often quite widely differing interpretations placed upon it. The term cardiac output monitoring refers to technology, whose primary purpose is to monitor global blood flow. The principles of the various technologies have been reviewed elsewhere.1

Pulmonary artery catheters: state of the controversy

Since 1970, pulmonary artery catheters (PACs) have been used in clinical practice to monitor the hemodynamic status of critically ill and injured patients. This technology was introduced and commercialized without considerable testing to determine safety and efficacy. After years of common clinical use, investigators identified potential increases in mortality associated with PAC use. For the past decade, investigators have studied various patient populations to elucidate the safety and efficacy of the PAC. This article reviews the historical context of PAC use, findings from recent clinical trials intended to determine safety and efficacy, issues with reliability and validity of PAC use, and complications associated with PAC use. Data from recent clinical trials do not support routine use of PACs, and the authors suggest that PAC-guided therapy should be the focus of study in future trials.

Continuous central venous saturation monitoring in pediatrics: a case report

OBJECTIVE

To report the use of a new pediatric central venous catheter that offers continuous central venous saturation (ScVO2) monitoring in the critically ill child.

DESIGN

Case report.

SETTING

Pediatric intensive care unit in a tertiary care children's hospital.

PATIENT

A 3-month-old child, following cardiac surgery, with an isolated decrease in central venous saturations.

INTERVENTIONS

Diagnosis of pericardial effusion by echocardiography followed by surgical drainage.

MEASUREMENTS AND MAIN RESULTS

ScVO2 readings quickly returned to normal, and the remaining patient course was uneventful.

CONCLUSIONS

We report the first case of a newly modified central venous catheter (PediaSat Oximetry Catheter, Edwards Lifesciences LLC, Irvine, CA) for children and demonstrate its utility in a patient with impaired oxygen delivery when traditional markers remain stable. This catheter enabled the rapid diagnosis of cardiac compromise due to pericardial effusion, leading to early treatment. Traditional central catheter functions and insertion technique are maintained, making the catheter potentially useful in any critically ill child.

Comparison of a radiofrequency-based wireless pressure sensor to swan-ganz catheter and echocardiography for ambulatory assessment of pulmonary artery pressure in heart failure

OBJECTIVES

The goal of this work was to evaluate the accuracy of a new heart failure (HF) sensor (HFS) (Heart Failure Sensor, CardioMEMS Inc., Atlanta, Georgia) pulmonary artery pressure (PAP) monitoring compared with Swan-Ganz (SG) (Hospira, Inc., Lake Forest, Illinois) catheterization and echocardiography (ECHO) in ambulatory HF patients.

BACKGROUND

There is an increasing interest in the development of ambulatory monitoring devices aiming to adjust therapy and prevent hospitalizations in HF patients.

METHODS

Twelve patients with HF and New York Heart Association functional class II to IV were included in this study. The HFS was deployed into the pulmonary artery under angiography, allowing wireless PAP measurement. Two independent blind operators performed 3 HFS measurements at each visit, with simultaneous ECHO at 2, 14, 30, 60, and 90 days. Swan-Ganz catheterization was performed at 0 and 60 days. Linear regression was used as a measure of agreement. Variability between methods and interobserver variability were evaluated by Bland-Altman analysis.

RESULTS

Mean age was 63 +/- 14.6 years. Systolic PAP was 64 +/- 22 mm Hg and 58 +/- 22 mm Hg for HFS and SG, respectively (p < 0.01). Both methods showed a significant correlation (r2 = 0.96 baseline, r2 = 0.90 follow-up, p < 0.01), with a mean difference of 6.2 +/- 4.5 mm Hg. Diastolic PAP was 23 +/- 14 mm Hg and 28 +/- 16 mm Hg for HFS and SG, respectively (r2 = 0.88 baseline, r2 = 0.48 follow-up, p < 0.01), with a mean difference of -1.6 +/- 6.8 mm Hg. Systolic PAP was 60 +/- 20 mm Hg and 62 +/- 12 mm Hg for HFS and ECHO, respectively (r2 = 0.75, p < 0.01), with a mean difference of -2.6 +/- 11 mm Hg. There was no significant interobserver difference.

CONCLUSIONS

The HFS provides an accurate method for PAP assessment in the intermediate follow-up of HF patients.

Pilot study on the influence of liver blood flow and cardiac output on the clearance of propofol in critically ill patients

OBJECTIVE

To investigate the effect of cardiac output and liver blood flow on propofol concentrations in critically ill patients in the intensive care unit.

METHODS

Five medical/surgical critically ill patients were enrolled in this preliminary study. Liver blood flow was measured using sorbitol. The cardiac output was measured by bolus thermodilution. NONMEM ver. V was applied for propofol pharmacokinetic analysis.

RESULTS

The clearance of propofol was positively influenced by the liver blood flow (P < 0.005), whereas no significant correlation between cardiac output and propofol clearance was found. A correlation between liver blood flow and cardiac output or cardiac index could not be assumed in this patient group.

CONCLUSIONS

Liver blood flow is a more predictive indicator than cardiac output for propofol clearance in critically ill patients when the techniques of hepatic sorbitol clearance and bolus thermodilution, respectively, are used. Further study is needed to determine the role played by liver blood flow and cardiac output on the pharmacokinetics of highly extracted drugs in order to reduce the observed high interindividual variabilities in response in critically ill patients.

Health technology assessment in critical care

BACKGROUND

Heath technology assessments (HTAs) evaluate the benefits and costs of devices for monitoring and therapy (and their associated requirements for human resources) which contribute to the high expense associated with ICU admission.

DISCUSSION

Given the limited resources available for health care and increasing demands, funds spent inefficiently or unnecessarily on technologies in the ICU may threaten the sustainability of the health care system or prevent other potentially cost-effective devices from being introduced into clinical care. We discuss the factors impeding the conducting of HTAs in the ICU and suggest strategies for change.

CONCLUSIONS

Despite the need for HTAs of ICU devices only few have been conducted. They should be undertaken more frequently, and their results used to influence clinical practice and hospital and regional-level policy decisions.