Early experience of a new extracorporeal carbon dioxide removal device for acute hypercapnic respiratory failure

BACKGROUND

Recent advances in the technology of extracorporeal respiratory assist systems have led to a renewed interest in extracorporeal carbon dioxide removal (ECCOR). The Hemolung is a new, low-flow, venovenous, minimally invasive, partial ECCOR device that has recently been introduced to clinical practice to aid in avoiding invasive ventilation or to facilitate lung-protective ventilation.

OBJECTIVE

We report our early experience on use, efficacy and safety of the Hemolung in three Australian intensive care units.

METHODS

Retrospective review of all patients with acute or acute-on-chronic respiratory failure (due to chronic obstructive pulmonary disease [COPD] with severe hypercapnic respiratory failure when non-invasive ventilation failed; acute respiratory distress syndrome; COPD; or asthma when lung-protective ventilation was not feasible due to hypercapnia) for whom the Hemolung was used.

RESULTS

Fifteen patients were treated with ECCOR. In four out of five patients, the aim of avoiding intubation was achieved. In the remaining 10 patients, the strategy of instituting lung-protective ventilation was successful. The median duration for ECCOR was 5 days (interquartile range, 3-7 days). The pH and PCO₂ improved significantly within 6 hours of instituting ECCOR, in conjunction with a significant reduction in minute ventilation. The CO₂ clearance was 90-100 mL/min. A total of 93% of patients survived to weaning from ECCOR, 73% survived to ICU discharge and 67% survived to hospital discharge.

CONCLUSION

Our data shows that ECCOR was safe and effective in this cohort. Further experience is vital to identify the patients who may benefit most from this promising therapy.

Anesthetic management of a myotonic dystrophy patient with paraganglionoma

Myotonic dystrophy (DM), though rare, can significantly complicate anesthesia due to muscular and extra-muscular involvement. When this condition is compounded by a pheochromocytoma, anesthetizing such patients becomes extra challenging. We present a case report of a 61-year-old lady with congenital DM, with the whole gamut of associated features, was diagnosed with a noradrenaline secreting paraganglionoma following investigation of refractory hypertension. We anesthetized her for an open resection of the lesion. The conduct of anesthesia and recovery of this patient is described. Our experience suggests that anesthetizing these patients though challenging can be safely managed with relaxant general anesthesia and epidural analgesia with meticulous care pre, intra and post-surgical intervention.

The Outcome and Predictors of Mortality in Patients Therapeutically Cooled Postcardiac Arrest

PURPOSE

To review the outcomes of patients postcardiac arrest admitted to a metropolitan intensive care unit (ICU) where therapeutic hypothermia is practiced.

MATERIALS AND METHODS

Patients admitted from 2004 to 2012 were reviewed. The management protocol included cooling to 33°C for 24 hours. The primary outcome assessed was hospital mortality. Secondary outcome measures included mortality in patients admitted to ICU after in-hospital cardiac arrest (IHCA) when compared to those with out-of-hospital cardiac arrest (OHCA) and to review initial cardiac rhythm as an indicator of mortality.

RESULTS

A total of 330 patients were included. The overall hospital mortality was 58.1%. Hospital mortality was significantly higher in patients who had OHCA when compared to IHCA (62.5% vs 51%; P = .04). Patients who had asystole and pulseless electrical activity (PEA) had a higher mortality when compared to ventricular tachycardia/ventricular fibrillation (VT/VF) arrest (81.7% vs 67.8% vs 41.9%, respectively; P < .01).

CONCLUSION

Patients admitted to ICU postcardiac arrest after therapeutic cooling have a high mortality. An initial rhythm of VT/VF confers a mortality benefit when compared to asystole and PEA.

The limitations in implementing and operating a rapid response system

Despite the widespread introduction of rapid response systems (RRS)/medical emergency teams (MET), there is still controversy regarding how effective they are. While there are some observational studies showing improved outcomes with RRS, there are no data from randomised controlled trials to support the effectiveness. Nevertheless, the MET system has become a standard of care in many healthcare organisations. In this review, we present an overview of the limitations in implementing and operating a RRS in modern healthcare.

Low-flow veno-venous extracorporeal carbon dioxide removal in the management of severe status asthmatics: a case report

Status asthmaticus is a life-threatening condition that requires intensive care management. Most of these patients have severe hypercapnic acidosis that requires lung protective mechanical ventilation. A small proportion of these patients do not respond to conventional lung protective mechanical ventilation or pharmacotherapy. Such patients have an increased mortality and morbidity. Successful use of extracorporeal membrane oxygenation (ECMO) is reported in such patients. However, the use of ECMO is invasive with its associated morbidity and is limited to specialised centres. In this report, we report the use of a novel, minimally invasive, low-flow extracorporeal carbon dioxide removal device in management of severe hypercapnic acidosis in a patient with life threatening status asthmaticus.

Cognitive function, quality of life and mental health in survivors of our-of-hospital cardiac arrest: a review

There is growing interest in the long-term outcomes of patients surviving out-of-hospital cardiac arrest (OHCA). This paper aims to summarise the available literature on the long-term cognitive, health-related quality of life (QoL) and mental health outcomes of survivors of OHCA. Between 30% and 50% of survivors of OHCA experience cognitive deficits for up to several years post-discharge. Deficits of attention, declarative memory, executive function, visuospatial abilities and verbal fluency are commonly reported. Survivors of OHCA appear to report high rates of mental illness, with up to 61% experiencing anxiety, 45% experiencing depression and 27% experiencing post-traumatic stress. Fatigue appears to be a commonly reported long-term outcome for survivors of OHCA. Investigations of long-term QoL for these patients have produced mixed findings. Carers of survivors of OHCA report high rates of depression, anxiety and post-traumatic stress, with insufficient social and financial support. The heterogeneous range of instruments used to assess cognitive function and QoL prevent any clear conclusions being drawn from the available literature. The potential biases inherent in this patient population and the interaction between QoL, cognitive performance and mental health warrant further investigation, as does the role of post-discharge support services in improving long-term patient outcomes.

Atrial Fibrillation and Mortality in Critically Ill Patients: A Retrospective Study

BACKGROUND

Although atrial fibrillation is common in critically ill patients, no large studies on its impact on patient mortality in general intensive care units have been done.

OBJECTIVE

To evaluate the association between atrial fibrillation and hospital mortality in critically ill patients.

METHODS

In a retrospective cohort study, critically ill patients who had atrial fibrillation during a 2-year period were compared with patients who did not. The primary outcome was death during the hospital stay. Secondary outcomes were duration of mechanical ventilation and lengths of stay in the intensive care unit and hospital.

RESULTS

Among a total of 2018 first-time admissions to the intensive care unit during the study period, 421 patients (20.9%) had atrial fibrillation. Patients with atrial fibrillation had higher mortality, significantly longer duration of mechanical ventilation, and longer stays in the intensive care unit and in the hospital than did patients without this cardiac arrhythmia. However, multiple logistic regression analysis indicated that atrial fibrillation was not independently associated with a higher risk for death.

CONCLUSION

Atrial fibrillation may not be independently associated with hospital mortality.

Is cooling still cool?

Therapeutic hypothermia (TH), where patients are cooled to between 32°C and 36°C for a period of 12-24 hours and then gradually rewarmed, may reduce the risk of ischemic injury to cerebral tissue following a period of insufficient blood flow. This strategy of TH could improve mortality and neurological function in patients who have experienced out-of-hospital cardiac arrest (OOHCA). The necessity of TH in OOHCA was challenged in late 2013 by a fascinating and potentially practice changing publication, which found that targeting a temperature of 36°C had similar outcomes to cooling patients to 33°C. This article reviews the current literature and summarizes the uncertainties and questions raised when considering cooling of patients at risk of hypoxic brain injury. Irrespective of whether TH or targeted temperature management is deployed in patients at risk of hypoxic brain injury, it would seem that avoiding hyperpyrexia is important and that a more rigorous approach to neurological evaluation is mandated.

Management of severe hypercapnia post cardiac arrest with extracorporeal carbon dioxide removal

Normocapnia is recommended in intensive care management of patients after out-of-hospital cardiac arrest. While normocapnia is usually achievable, it may be therapeutically challenging, particularly in patients with airflow obstruction. Conventional mechanical ventilation may not be adequate to provide optimal ventilation in such patients. One of the recent advances in critical care management of hypercapnia is the advent of newer, low-flow extracorporeal carbon dioxide clearance devices. These are simpler and less invasive than conventional extracorporeal devices. We report the first case of using a novel, extracorporeal carbon dioxide removal device in Australia on a patient with out-of-hospital cardiac arrest where mechanical ventilation failed to achieve normocapnia.

Fatal skin and soft tissue infection of multidrug resistant Acinetobacter baumannii: A case report

INTRODUCTION

Acinetobacter baumannii is usually associated with respiratory tract, urinary tract and bloodstream infections. Recent reports suggest that it is increasingly causing skin and soft tissue infections. It is also evolving as a multidrug resistant organism that can be difficult to treat. We present a fatal case of multidrug resistant A. baumannii soft tissue infection and review of relevant literature.

PRESENTATION OF CASE

A 41 year old morbidly obese man, with history of alcoholic liver disease presented with left superficial pre-tibial abrasions and cellulitis caused by multidrug resistant (MDR) A. baumannii. In spite of early antibiotic administration he developed extensive myositis and fat necrosis requiring extensive and multiple surgical debridements. He deteriorated despite appropriate antibiotic therapy and multiple surgical interventions with development of multi-organ failure and died.

DISCUSSION

Managing Acinetobacter infections remains difficult due to the array of resistance and the pathogens ability to develop new and ongoing resistance. The early diagnosis of necrotizing soft tissue infection may be challenging, but the key to successful management of patients with necrotizing soft tissue infection are early recognition and complete surgical debridement.

CONCLUSION

A. baumannii is emerging as an important cause of severe, life-threatening soft tissue infections. Multidrug resistant A. baumannii soft tissue infections may carry a high mortality in spite of early and aggressive treatment. Clinicians need to consider appropriate early empirical antibiotic coverage or the use of combination therapy to include MDR A. baumannii as a cause of skin and soft tissue infections.

To ventilate, oscillate, or cannulate?

Ventilatory management of acute respiratory distress syndrome has evolved significantly in the last few decades. The aims have shifted from optimal gas transfer without concern for iatrogenic risks to adequate gas transfer while minimizing lung injury. This change in focus, along with improved ventilator and multiorgan system management, has resulted in a significant improvement in patient outcomes. Despite this, a number of patients develop hypoxemic respiratory failure refractory to lung-protective ventilation (LPV). The intensivist then faces the dilemma of either persisting with LPV using adjuncts (neuromuscular blocking agents, prone positioning, recruitment maneuvers, inhaled nitric oxide, inhaled prostacyclin, steroids, and surfactant) or making a transition to rescue therapies such as high-frequency oscillatory ventilation (HFOV) and/or extracorporeal membrane oxygenation (ECMO) when both these modalities are at their disposal. The lack of quality evidence and potential harm reported in recent studies question the use of HFOV as a routine rescue option. Based on current literature, the role for venovenous (VV) ECMO is probably sequential as a salvage therapy to ensure ultraprotective ventilation in selected young patients with potentially reversible respiratory failure who fail LPV despite neuromuscular paralysis and prone ventilation. Given the risk profile and the economic impact, future research should identify the patients who benefit most from VV ECMO. These choices may be further influenced by the emerging novel extracorporeal carbon dioxide removal devices that can compliment LPV. Given the heterogeneity of acute respiratory distress syndrome, each of these modalities may play a role in an individual patient. Future studies comparing LPV, HFOV, and VV ECMO should not only focus on defining the patients who benefit most from each of these therapies but also consider long-term functional outcomes.

Futility of medical treatment in current medical practice

Intensive care provides support for acute reversible organ failure and most patients who receive intensive care recover from their illness. In some patients organ failure may become irreversible and in these patients further treatment or organ support may be considered futile. Emerging technologies and expertise can enable the medical profession to prolong life / death indefinitely without curing or controlling the underlying disease process. Introduction of ultramodern organ supports such as extracorporeal life-support systems, ventricular assist devices and organ transplantation surgeries have introduced some degree of ambiguity in defining futility of care. Furthermore medico legal implications of futility of care introduce further complexities in defining and instituting futile treatments. In this review we discuss the evolution of the concept of futility of care, review the various meanings of the term "futility of care", explore the complexities of management when care is considered futile, offer suggestions as to how such patients and their families could be managed. We also review the legal framework when consensus is not achieved.

Carbon dioxide clearance in critical care

Lung protective ventilation limiting tidal volumes and airway pressures were proven to reduce mortality in patients with acute severe respiratory failure. Hypercapnia and hypercapnic acidosis is often noted with lung protective ventilation. While the protective effects of lung protective ventilation are well recognised, the role of hypercapnia and hypercapnic acidosis remains debatable. Some clinicians argue that hypercapnia and hypercapnic acidosis protect the lungs and may be associated with improved outcomes. To the contrary, some clinicians do not tolerate hypercapnic acidosis and use various techniques including extracorporeal carbon dioxide elimination to treat hypercapnia and acidosis. This review aims at defining the effects of hypercapnia and hypercapnic acidosis with a focus on the pros and cons of clearing carbon dioxide and the modalities that may enhance carbon dioxide clearance.

Stress hyperglycemia may not be harmful in critically ill patients with sepsis

BACKGROUND

Stress hyperglycemia (SH) is commonly seen in critically ill patients. It has been shown to be associated with adverse outcomes in some groups of patients. The effects of SH on critically ill patients with sepsis have not been well studied. We aimed to evaluate the effects of SH in critically ill patients with sepsis.

METHODS

In this retrospective study, patients with sepsis admitted to intensive care unit (ICU) over a 5-year period were included.

RESULTS

Of 297 patients, 204 (68.7%) had SH during the study period. The mean blood glucose level in patients with SH was 8.7 mmol/L compared with 5.9 mmol/L in those without SH (P < .05). There were no statistically significant differences in age; sex; sepsis severity; cardiovascular, respiratory, and renal comorbidities; requirement of mechanical ventilation; inotropes; and Acute Physiology, Age, and Chronic Health Evaluation III and Simplified Acute Physiology 2 scores on ICU admission. Intensive care unit mortality was significantly lower in patients who had SH. The median duration of ICU and hospital length of stay was longer in patients with SH. On logistic regression analysis, the presence of SH was associated with reduced ICU mortality. Subgroup analysis revealed SH to be protective in patients with septic shock.

CONCLUSION

Stress hyperglycemia may not be harmful in critically ill patients with sepsis. Patients with SH had lower ICU mortality.

Effectiveness of extracorporeal membrane oxygenation when conventional ventilation fails: valuable option or vague remedy?

The mortality and morbidity of patients with severe acute respiratory distress syndrome (ARDS) remains high despite the advances in intensive care practice. The low-tidal-volume ventilation strategy (ARDS net protocol) has been shown to be effective in improving survival. Unfortunately, however, some patients have such severe ARDS that they cannot be managed with the ARDS net strategy. In these patients, rescue therapies such as high-frequency ventilation, prone ventilation, nitric oxide, and extracorporeal membrane oxygenation (ECMO) are considered. The CESAR trial has shown that an ECMO-based protocol improved survival without severe disability as compared with conventional ventilation. The recent increased incidence of severe respiratory failure due to H1N1 influenza pandemic has led to an increased use of ECMO. Although several reports showed ECMO use to be encouraging, some scepticism remains. In this article, we reviewed the usefulness of ECMO in patients with severe ARDS in the light of current evidence.

Cardiac troponin I does not independently predict mortality in critically ill patients with severe sepsis

OBJECTIVE

Patients with sepsis often have elevated cardiac troponin I even in the absence of coronary artery disease. The prognostic value of cardiac troponins in critically ill patients with sepsis remains debatable. Our objective was to evaluate the prognostic value of cardiac troponin I in critically ill patients with severe sepsis.

METHODS

In this retrospective study, we included patients with severe sepsis who had troponin assayed within 12 h of admission to intensive care over a 6 year period. Patients who had myocardial infarction at intensive care admission in the setting of sepsis were excluded. Included patients were classified into two groups based on their serum troponin I levels: low troponin group (troponin ≤ 0.1 µg/L) and elevated troponin group (troponin > 0.1 µg/L). The primary outcome of interest was hospital mortality. The secondary outcome measures included intensive care mortality, intensive care and hospital length of stay.

RESULTS

A total of 382 patients were admitted to intensive care with sepsis. Of these, 293 patients were included in analyses. There was a statistically significant difference in hospital (15% vs 36.1%; P < 0.01) and intensive care (11% vs 25%; P < 0.01) mortality, but not in intensive care and hospital duration of stay. Logistic regression analysis revealed temperature, simplified acute physiology score II and serum lactate to be independent predictors of hospital mortality. Cardiac troponin I was not an independent predictor of hospital mortality.

CONCLUSION

Critically ill patients with severe sepsis who had elevated troponin had increased hospital and intensive care mortality. However, cardiac troponin I did not independently predict hospital mortality.

Hypothermia predicts mortality in critically ill elderly patients with sepsis

BACKGROUND

Advanced age is one of the factors that increase mortality in intensive care. Sepsis and multi-organ failure are likely to further increase mortality in elderly patients.We compared the characteristics and outcomes of septic elderly patients (> 65 years) with younger patients (≤ 65 years) and identified factors during the first 24 hours of presentation that could predict mortality in elderly patients.

METHODS

This study was conducted in a Level III intensive care unit with a case mix of medical and surgical patients excluding cardiac and neurosurgical patients.We performed a retrospective review of all septic patients admitted to our ICU between July 2004 and May 2007. In addition to demographics and co-morbidities, physiological and laboratory variables were analysed to identify early predictors of mortality in elderly patients with sepsis.

RESULTS

Of 175 patients admitted with sepsis, 108 were older than 65 years. Elderly patients differed from younger patients with regard to sex, temperature (37.2°C VS 37.8°C p < 0.01), heart rate, systolic blood pressure, pH, HCO3, potassium, urea, creatinine, APACHE III and SAPS II. The ICU and hospital mortality was significantly higher in elderly patients (10.6% Vs 23.14% (p = 0.04) and 19.4 Vs 35.1 (p = 0.02) respectively). Elderly patients who died in hospital had a significant difference in pH, HCO3, mean blood pressure, potassium, albumin, organs failed, lactate, APACHE III and SAPS II compared to the elderly patients who survived while the mean age and co-morbidities were comparable. Logistic regression analysis identified temperature (OR [per degree centigrade decrease] 0.51; 95% CI 0.306- 0.854; p = 0.010) and SAPS II (OR [per point increase]: 1.12; 95% CI 1.016-1.235; p = 0.02) during the first 24 hours of admission to independently predict increased hospital mortality in elderly patients.

CONCLUSIONS

The mortality in elderly patients with sepsis is higher than the younger patients. Temperature (hypothermia) and SAPS II scores during the first 24 hours of presentation independently predict hospital mortality.

High-flow nasal oxygen vs high-flow face mask: a randomized crossover trial in extubated patients

PURPOSE

Oxygen delivery after extubation is critical to maintain adequate oxygenation and to avoid reintubation. The delivery of oxygen in such situations is usually by high-flow face mask (HFFM). Yet, this may be uncomfortable for some patients. A recent advance in oxygen delivery technology is high-flow nasal prongs (HFNP). There are no randomized trials comparing these 2 modes.

METHODS

Patients were randomized to either protocol A (n = 25; HFFM followed by HFNP) or protocol B (n = 25; HFNP followed by HFFM) after a stabilization period of 30 minutes after extubation. The primary objective was to compare the efficacy of HFNP to HFFM in maintaining gas exchange as measured by arterial blood gas. Secondary objective was to compare the relative effects on heart rate, blood pressure, respiratory rate, comfort, and tolerance.

RESULTS

Patients in both protocols were comparable in terms of age, demographic, and physiologic variables including arterial blood gas, blood pressure, heart rate, respiratory rate, Glasgow Coma Score, sedation, and Acute Physiology and Chronic Health Evaluation (APACHE) III scores. There was no significant difference in gas exchange, respiratory rate, or hemodynamics. There was a significant difference (P = .01) in tolerance, with nasal prongs being well tolerated. There was a trend (P = .09) toward better patient comfort with HFNP.

CONCLUSIONS

High-flow nasal prongs are as effective as HFFM in delivering oxygen to extubated patients who require high-flow oxygen. The tolerance of HFNP was significantly better than in HFFM.

Randomised controlled trial and parallel economic evaluation of conventional ventilatory support versus extracorporeal membrane oxygenation for severe adult respiratory failure (CESAR)

OBJECTIVES

To determine the comparative effectiveness and cost-effectiveness of conventional ventilatory support versus extracorporeal membrane oxygenation (ECMO) for severe adult respiratory failure.

DESIGN

A multicentre, randomised controlled trial with two arms.

SETTING

The ECMO centre at Glenfield Hospital, Leicester, and approved conventional treatment centres and referring hospitals throughout the UK.

PARTICIPANTS

Patients aged 18-65 years with severe, but potentially reversible, respiratory failure, defined as a Murray lung injury score > or = 3.0, or uncompensated hypercapnoea with a pH < 7.20 despite optimal conventional treatment.

INTERVENTIONS

Participants were randomised to conventional management (CM) or to consideration of ECMO.

MAIN OUTCOME MEASURES

The primary outcome measure was death or severe disability at 6 months. Secondary outcomes included a range of hospital indices: duration of ventilation, use of high frequency/oscillation/jet ventilation, use of nitric oxide, prone positioning, use of steroids, length of intensive care unit stay, and length of hospital stay - and (for ECMO patients only) mode (venovenous/veno-arterial), duration of ECMO, blood flow and sweep flow.

RESULTS

A total of 180 patients (90 in each arm) were randomised from 68 centres. Three patients in the conventional arm did not give permission to be followed up. Of the 90 patients randomised to the ECMO arm, 68 received that treatment. ECMO was not given to three patients who died prior to transfer, two who died in transit, 16 who improved with conventional treatment given by the ECMO team and one who required amputation and could not therefore be heparinised. Ninety patients entered the CM (control) arm, three patients later withdrew and refused follow-up (meaning that they were alive), leaving 87 patients for whom primary outcome measures were available. CM consisted of any treatment deemed appropriate by the patient's intensivist with the exception of extracorporeal gas exchange. No CM patients received ECMO, although one received a form of experimental extracorporeal arteriovenous carbon dioxide removal support (a clear protocol violation). Fewer patients in the ECMO arm than in the CM arm had died or were severely disabled 6 months after randomisation, [33/90 (36.7%) versus 46/87 (52.9%) respectively]. This equated to one extra survivor for every six patients treated. Only one patient (in the CM arm) was known to be severely disabled at 6 months. Patients allocated to ECMO incurred average total costs of 73,979 pounds compared with 33,435 pounds for those undergoing CM (UK prices, 2005). A lifetime model predicted the cost per quality-adjusted life-year (QALY) of ECMO to be 19,252 pounds (95% confidence interval 7622 pounds to 59,200 pounds) at a discount rate of 3.5%. Lifetime QALYs gained were 10.75 for the ECMO group compared with 7.31 for the conventional group. Costs to patients and their relatives, including out of pocket and time costs, were higher for patients allocated to ECMO.

CONCLUSIONS

Compared with CM, transferring adult patients with severe but potentially reversible respiratory failure to a single centre specialising in the treatment of severe respiratory failure for consideration of ECMO significantly increased survival without severe disability. Use of ECMO in this way is likely to be cost-effective when compared with other technologies currently competing for health resources.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN47279827.

End of life management of adult patients in an Australian metropolitan intensive care unit: A retrospective observational study

BACKGROUND

Death in the intensive care unit is often predictable. End of life management is often discussed and initiated when futility of care appears evident. Respect for patients wishes, dignity in death, and family involvement in the decision-making process is optimal. This goal may often be elusive.

PURPOSE

Our purpose was to review the end of life processes and family involvement within our Unit.

METHODS

We conducted a chart audit of all deaths in our 10 bed Unit over a 12-month period, reviewing patient demographics, diagnosis on admission, patient acuity, expectation of death and not-for-resuscitation status. Discussions with the family, treatments withheld and withdrawn and extubation practices were documented. The presence of family or next-of-kin at the time of death, the time to death after withdrawal of therapy and family concerns were recorded.

RESULTS

There were 70 patients with a mean age of 69 years. Death was expected in 60 patients (86%) and not-for-resuscitation was documented in 58 cases (85%). Family discussions were held in 63 cases (90%) and treatment was withdrawn in 34 deaths (49%). After withdrawal of therapies, 31 patients (44%) died within 6h. Ventilatory support was withdrawn in 24 cases (36%). Family members were present at the time of death in 46 cases (66%). Family concerns were documented about the end of life care in only 1 case (1.4%).

CONCLUSION

Our data suggests that death in our Unit was often predictable and that end of life management was a consultative process.

Efficacy and economic assessment of conventional ventilatory support versus extracorporeal membrane oxygenation for severe adult respiratory failure (CESAR): a multicentre randomised controlled trial

BACKGROUND

Severe acute respiratory failure in adults causes high mortality despite improvements in ventilation techniques and other treatments (eg, steroids, prone positioning, bronchoscopy, and inhaled nitric oxide). We aimed to delineate the safety, clinical efficacy, and cost-effectiveness of extracorporeal membrane oxygenation (ECMO) compared with conventional ventilation support.

METHODS

In this UK-based multicentre trial, we used an independent central randomisation service to randomly assign 180 adults in a 1:1 ratio to receive continued conventional management or referral to consideration for treatment by ECMO. Eligible patients were aged 18-65 years and had severe (Murray score >3.0 or pH <7.20) but potentially reversible respiratory failure. Exclusion criteria were: high pressure (>30 cm H(2)O of peak inspiratory pressure) or high FiO(2) (>0.8) ventilation for more than 7 days; intracranial bleeding; any other contraindication to limited heparinisation; or any contraindication to continuation of active treatment. The primary outcome was death or severe disability at 6 months after randomisation or before discharge from hospital. Primary analysis was by intention to treat. Only researchers who did the 6-month follow-up were masked to treatment assignment. Data about resource use and economic outcomes (quality-adjusted life-years) were collected. Studies of the key cost generating events were undertaken, and we did analyses of cost-utility at 6 months after randomisation and modelled lifetime cost-utility. This study is registered, number ISRCTN47279827.

FINDINGS

766 patients were screened; 180 were enrolled and randomly allocated to consideration for treatment by ECMO (n=90 patients) or to receive conventional management (n=90). 68 (75%) patients actually received ECMO; 63% (57/90) of patients allocated to consideration for treatment by ECMO survived to 6 months without disability compared with 47% (41/87) of those allocated to conventional management (relative risk 0.69; 95% CI 0.05-0.97, p=0.03). Referral to consideration for treatment by ECMO led to a gain of 0.03 quality-adjusted life-years (QALYs) at 6-month follow-up [corrected]. A lifetime model predicted the cost per QALY of ECMO to be pound19 252 (95% CI 7622-59 200) at a discount rate of 3.5%.

INTERPRETATION

We recommend transferring of adult patients with severe but potentially reversible respiratory failure, whose Murray score exceeds 3.0 or who have a pH of less than 7.20 on optimum conventional management, to a centre with an ECMO-based management protocol to significantly improve survival without severe disability. This strategy is also likely to be cost effective in settings with similar services to those in the UK.

FUNDING

UK NHS Health Technology Assessment, English National Specialist Commissioning Advisory Group, Scottish Department of Health, and Welsh Department of Health.

Fatal thrombosis with activated factor VII in a paediatric patient on extracorporeal membrane oxygenation

Bleeding remains a potential complication for patients requiring extracorporeal life support systems. Recombinant activated factor VII (rFVIIa) is one of the drugs used in controlling bleeding. Its use is generally found to be safe. We report a paediatric patient who developed fatal thrombosis with the use of rFVIIa whilst on extracorporeal membrane oxygenation and discuss the possible factors that lead to fatal thrombosis.

Predictors of outcome of ruptured aortic aneurysms in a metropolitan hospital

The mortality in patients presenting with ruptured abdominal aortic aneurysm remains high. In this study we aimed to assess the outcome and factors predicting the mortality in patients admitted to a teaching hospital with the diagnosis of ruptured abdominal aortic aneurysm. During the study period (July 2001 to July 2007) all patients admitted with a diagnosis of a ruptured abdominal aortic aneurysm were included. There was a total of 62 patients with a mean age of 76 years. The hospital mortality was 32.3% (20 patients). Twelve patients (19.4%) were discharged home, 25 patients (40.3%) were discharged to rehabilitation and five patients (8%) were discharged to other hospitals for further care. There was a significant difference between survivors and non-survivors in age, loss of consciousness at presentation and duration of hospital stay. Logistic regression analysis of these variables suggests the presence of chronic obstructive pulmonary disease (P=0.04, odds ratio 6.7, 95% confidence interval 1.1 to 41.3) and age (P=0.02, odds ratio 1.2, 95% confidence intervals 1.0 to 1.3) to be independently associated with mortality. These results compare favourably with published Australian as well as the international data.

Methods of data collection and analysis for the economic evaluation alongside a national, multi-centre trial in the UK: conventional ventilation or ECMO for Severe Adult Respiratory Failure (CESAR)

BACKGROUND

Extracorporeal Membrane Oxygenation (ECMO) is a technology used in treatment of patients with severe but potentially reversible respiratory failure. A multi-centre randomised controlled trial (CESAR) was funded in the UK to compare care including ECMO with conventional intensive care management. The protocol and funding for the CESAR trial included plans for economic data collection and analysis. Given the high cost of treatment, ECMO is considered an expensive technology for many funding systems. However, conventional treatment for severe respiratory failure is also one of the more costly forms of care in any health system.

METHODS/DESIGN

The objectives of the economic evaluation are to compare the costs of a policy of referral for ECMO with those of conventional treatment; to assess cost-effectiveness and the cost-utility at 6 months follow-up; and to assess the cost-utility over a predicted lifetime. Resources used by patients in the trial are identified. Resource use data are collected from clinical report forms and through follow up interviews with patients. Unit costs of hospital intensive care resources are based on parallel research on cost functions in UK NHS intensive care units. Other unit costs are based on published NHS tariffs. Cost effectiveness analysis uses the outcome: survival without severe disability. Cost utility analysis is based on quality adjusted life years gained based on the Euroqol EQ-5D at 6 months. Sensitivity analysis is planned to vary assumptions about transport costs and method of costing intensive care. Uncertainty will also be expressed in analysis of individual patient data. Probabilities of cost effectiveness given different funding thresholds will be estimated.

DISCUSSION

In our view it is important to record our methods in detail and present them before publication of the results of the trial so that a record of detail not normally found in the final trial reports can be made available in the public domain.

TRIAL REGISTRATIONS

The CESAR trial registration number is ISRCTN47279827.