Experience with the Avalon® bicaval double-lumen veno-venous cannula for neonatal respiratory ECMO.

OBJECTIVE: We report a single centre experience of neonatal respiratory ECMO using the Avalon® double-lumen venous cannula and compare it with reports in the literature. RESULTS: Between 2008 and 2012, the Avalon® cannula was used in 72 neonates: median age at cannulation was 1.8 days (IQR 1.2-2.8 days) and bodyweight 3.4 Kg (3.0-3.7 Kg). Meconium aspiration syndrome (61.1%), persistent hypertension of the newborn (25%) and congenital diaphragmatic hernia (5.6%) were the most common diagnoses. Complications occurred in 19 patients (26.4%): cannula site bleeding in 6 (8.3%), the cannula perforating the right atrial wall and requiring emergency midline sternotomy in 5 (6.9%) and the cannula needing repositioning in 3 (4.2%). Overall survival at discharge or transfer to the referring hospital was 88.8%. Successful wean off ECMO occurred in 68 patients (94.4%) after a median of 90.5 hours (63.4-136.11). ECMO support was withdrawn in 4 patients (5.6%). CONCLUSIONS: The Avalon® dual-lumen veno-venous cannula can be used for respiratory ECMO in the neonatal population. However, as the incidence of right atrial perforation is not negligible, we suspended its used in this group of patients.

The need for thoracic surgery in adult patients receiving extracorporeal membrane oxygenation: a 16-year experience.

OBJECTIVES: Patients on extracorporeal membrane oxygenation (ECMO) are at risk from thoracic complications such as bleeding or pneumothorax, which may subsequently necessitate thoracic surgical intervention. We aimed to: 1) analyse the indication and nature of thoracic surgical intervention in these patients and 2) analyse the effect of a change in the ECMO circuit from roller pump to centrifugal pump on transfusion requirements pre and post thoracotomy. METHODS: We retrospectively reviewed a prospectively collected database of 569 adults put on ECMO between 1995 and 2011. Patients undergoing thoracotomy were identified and outcomes were statistically analysed. RESULTS: Forty thoracotomies were performed in 18 patients [61% male, median age 31 (14-56) years, one bilateral procedure]. The indications for ECMO included: pneumonia 14/18 (78%), trauma 2/18 (11%) and other 2/18 (11%). Median duration on ECMO was 13 (1-257) days and the time to initial thoracotomy was 10 (1-183) days. The indications for thoracotomy were: excessive bleeding post chest drain insertion (11/19, 58%), uncontrolled air leak (9/19, 47%) and pleural effusion (4/19, 21%). The primary operations were 12/19 (63%) evacuation of haemothorax, 3/19 (16%) lung repair, 2/19 (11%) diagnostic lung biopsy and 2/19 (11%) other. Ten patients needed a further 21 thoracotomies (3 lobectomies); average 2 (1-5) per patient. In total, 30/40 (75%) thoracotomies were performed for bleeding complication. The change from roller to centrifugal pump trended towards a reduction in mean transfusion requirements in these patients following thoracotomy (11.5 versus 4 units, p=0.14). The in-hospital mortality was 7/18 (39%) patients. There were no statistically significant predictors of poor outcome. CONCLUSIONS: The need for thoracotomy whilst on ECMO is 3.2% in this large series. Intervention may be complicated, thus, either ECMO specialists should have thoracic training or thoracic surgeons should be on-site. Potential mortality is high and, although not statistically significant, a difference in transfusion requirements was observed following the change of circuit.

Oseltamivir pharmacokinetics in critically ill adults receiving extracorporeal membrane oxygenation support.

Extracorporeal membrane oxygenation (ECMO) is known to affect pharmacokinetics and hence optimum dosing. The aim of this open label, prospective study was to investigate the pharmacokinetics of oseltamivir (prodrug) and oseltamivir carboxylate (active metabolite) during ECMO. Fourteen adult patients with suspected or confirmed H1N1 influenza were enrolled in the study. Oseltamivir 75 mg was enterally administered twice daily and blood samples for pharmacokinetic assessment were taken on day 1 and 5. A multi-compartmental model to describe the pharmacokinetics of oseltamivir and oseltamivir carboxylate was developed using a non-linear mixed effects modelling approach. The median (range) clearance of oseltamivir carboxylate was 15.8 (4.8-36.6) l/hour, lower than the reported mean value of 21.5 l/hour in healthy adults. The median (range) steady state volume of distribution of oseltamivir carboxylate was 179 (61-436) litres, much greater than healthy adults but similar to previous reports in critically ill patients. Substantial 'between subject' variability in systemic exposure to oseltamivir carboxylate was revealed; median (range) area under the curve and Cmax were 4346 (644-13660) ng/hour/ml and 509 (54-1277) ng/ml, respectively. Both area under the curve and Cmax were significantly correlated with serum creatinine (r2=0.37, P=0.02 and r2=0.29, P=0.02, respectively). Systemic exposure to oseltamivir carboxylate following the administration of enteral oseltamivir 75 mg twice daily in adult ECMO patients is comparable to those in ambulatory patients and far in excess of concentrations required to maximally inhibit neuraminidase activity of the H1N1 virus. Dosage adjustment for ECMO, per se, appears not to be necessary; however, doses should be reduced in patients with renal dysfunction.

Organization of extracorporeal membrane oxygenation for acute respiratory distress syndrome in the United Kingdom.

This article reviews the evolution of extracorporeal membrane oxygenation (ECMO) in the United Kingdom to treat patients with refractory acute respiratory distress. The UK centralized commissioning of public health care has delivered a coherent high-quality national adult ECMO service and defined the key factors in the designation as adult ECMO centre. This strategy seems adequate to provide for the needs of the population and avoid the danger of occasional practice by teams who do not undertake ECMO regularly.

Cet article présente une mise au point sur le développement au RoyaumeUni de l'extracorporeal membrane oxygenation (ECMO) pour le traitement du syndrome de détresse respiratoire aiguë. La commission centrale de santé publique du pays a soutenu une politique restrictive mais de qualité, en définissant des critères précis permettant à un centre de devenir centre expert d'ECMO. Il semble que cette stratégie ait porté ses fruits en répondant de façon adéquate aux besoins de la population et en évitant une pratique anarchique de l'ECMO dans des centres qui ne pourraient pas avoir une pratique régulière et suffisante de cette technique.

Management benefits and safety of computed tomography in patients undergoing extracorporeal membrane oxygenation therapy: experience of a single centre.

AIM: To evaluate the benefits and logistical safety of computed tomography (CT) imaging in patients undergoing extracorporeal membrane oxygenation (ECMO) therapy in a single institution. MATERIALS AND METHODS: Over a period of 25 months, 134 patients (80 neonates, 19 children, and 35 adults) underwent ECMO therapy at this institution. The imaging of these patients was reviewed to identify patients who had undergone CT imaging whilst on ECMO. Patient notes were retrospectively reviewed. CT findings and subsequent decisions were analysed to assess the benefit of CT imaging. Complications arising due to the logistics of performing the scan were analysed to assess the safety of performing CT in ECMO patients. RESULTS: Of 134 patients, 14 (10%) had a total of 15 CT examinations whilst undergoing ECMO therapy. Indications for CT included new neurology, increased respiratory demand, and increasing requirement for high ECMO flows. There were no major complications and two minor complications associated with the logistics of performing a CT examination on an ECMO patient. Significant findings resulted from 73.3% (11/15) of the CT examinations, and in all 15 examinations information was provided that was used in making further management decisions, including, in some cases, withdrawal of ECMO therapy. CONCLUSION: With an experienced team, CT imaging of patients on ECMO can be performed safely. CT provides valuable information for subsequent management of patients undergoing ECMO therapy.

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.

Pseudocalcification on chest CT scan.

Liquid ventilation with perfluorocarbons is used in severe respiratory failure that cannot be managed by conventional methods. Very little is known about the use of liquid ventilation in paediatric patients with respiratory failure and there are no reports describing the distribution and excretion of perfluorocarbons in paediatric patients with severe respiratory failure. The aim of this report is to highlight the prolonged retention of perfluorocarbons in a paediatric patient, mimicking pulmonary calcification and misleading the interpretation of the chest CT scan. A 10-year-old girl was admitted to our intensive care unit with severe respiratory failure due to miliary tuberculosis. Extracorporeal membrane oxygenation (ECMO) was used to support gas exchange and partial liquid ventilation (PLV) with perfluorodecalin was used to aid in oxygenation, lavage the lungs and clear thick secretions. The patient developed a pneumothorax (fluorothorax) on the next day and PLV was discontinued. Multiple bronchoalveolar lavages were performed to clear thick secretions. With no improvement in lung function over the next month a CT scan of the chest was performed. This revealed extensive pulmonary fibrosis and multiple high attenuation lesions suggestive of pulmonary calcification. To exclude perfluorodecalin as the cause for high attenuation lesions, a sample of perfluorodecalin was scanned to estimate the Hounsfield unit density, which was similar to the density of high attenuation lesions on chest CT scan. High-density opacification should be interpreted with caution, especially following liquid ventilation.

Extracorporeal membrane oxygenation and extracorporeal albumin dialysis in pediatric patients with sepsis and multi-organ dysfunction syndrome.

Extracorporeal membrane oxygenation (ECMO) is used in managing patients with potentially reversible cardio-respiratory failure refractory to conventional methods. Multiorgan dysfunction syndrome (MODS), usually due to sepsis, remains the main cause of mortality in such patients. We report a series of six pediatric patients with sepsis-induced MODS where extracorporeal albumin dialysis (EAD) was used while the patients were on ECMO. The age of the patients ranged between 1 month and 17 years. The mean pediatric index of mortality (PIM) score at admission was 67.5%. All these patients further deteriorated with MODS and EAD was used as rescue therapy. At institution of EAD, 4 patients had dysfunction of 4 organs and 2 patients had dysfunction of 5 organs. The number of EAD cycles ranged between 1 and 3. Three out of the 6 patients (50%) survived to discharge from the intensive care unit and two of the six patients (33%) survived to hospital discharge. According to our previous experience and published results, all these patients would have been expected to die. The present results suggest that EAD may prove to have a role in the treatment of pediatric patients with sepsis-induced MODS. Further research is required to identify the group of patients who would benefit most by EAD as well as understand the clearance of inflammatory mediators and other mechanisms involved with the use of EAD.

Identification of systems failures in successful paediatric cardiac surgery.

Patient safety will benefit from an approach to human error that examines systemic causes, rather than blames individuals. This study describes a direct observation methodology, based on a threat and error model, prospectively to identify types and sources of systems failures in paediatric cardiac surgery. Of substantive interest were the range, frequency and types of failures that could be identified and whether minor failures could accumulate to form more serious events, as has been the case in other industries. Check lists, notes and video recordings were employed to observe 24 successful operations. A total of 366 failures were recorded. Coordination and communication problems, equipment problems, a relaxed safety culture, patient-related problems and perfusion-related problems were most frequent, with a smaller number of skill, knowledge and decision-making failures. Longer and more risky operations were likely to generate a greater number of minor failures than shorter and lower risk operations, and in seven higher-risk cases frequently occurring minor failures accumulated to threaten the safety of the patient. Non-technical errors were more prevalent than technical errors and task threats were the most prevalent systemic source of error. Adverse events in surgery are likely to be associated with a number of recurring and prospectively identifiable errors. These may be co-incident and cumulative human errors predisposed by threats embedded in the system, rather than due to individual incompetence or negligence. Prospectively identifying and reducing these recurrent failures would lead to improved surgical standards and enhanced patient safety.

Traumatic lung injury treated by extracorporeal membrane oxygenation (ECMO).

BACKGROUND: Conventional mechanical ventilation is the mainstay of treatment for severe respiratory failure associated with trauma. However, when extensive lung injury is present, this technique may not be sufficient to prevent hypoxia, and furthermore, may exacerbate pulmonary damage by barotrauma. Extracorporeal membrane oxygenation (ECMO) has been used successfully in critically ill adult trauma patients and can offer an additional treatment modality. This study reports the use of ECMO in a cohort of adults referred with severe respiratory failure following trauma. METHODS: Retrospective analysis over an 8-year period of all 28 adult patients referred to a single tertiary unit for ECMO support. Survival relative to Injury severity score (ISS), lung injury score (Murray grade), duration of treatment and patient age was evaluated. RESULTS: Twenty of 28 patients who received ECMO with severe trauma related respiratory failure (mean PaO2/FiO2 of 62 mmHg) survived. Most patients had long bone fractures, blunt chest trauma, or combined injuries. Lung injury and injury severity scores, patient age, ECMO duration and oxygenation indices pre-ECMO (PaO2/FiO2) were similar in both the survivor and non-survivor groups. CONCLUSION: A high proportion of trauma patients treated with ECMO for severe lung injury survived. This outcome appears to compare favourably to conventional ventilation techniques and may have a role in patients who develop acute severe respiratory distress associated with trauma.

Postoperative extracorporeal membrane oxygenation for severe intraoperative SIRS 10 h after multiple trauma.

A 34-yr-old male suffered multiple trauma in a road traffic accident. He required right thoracotomy and laparotomy to control exanguinating haemorrhage, and received 93 u blood and blood products. Intraoperatively, he developed severe systemic inflammatory response syndrome (SIRS) with coagulopathy and respiratory failure. At the end of the procedure, the mean arterial pressure (MAP) was 40 mm Hg, arterial blood gas analysis showed a pH of 6.9, Pa(CO(2)) 12 kPa, and Pa(O(2)) 4.5 kPa, and his core temperature was 29 degrees C. There was established disseminated intravascular coagulation. The decision was made to stabilize the patient on veno-venous extracorporeal membrane oxygenation (ECMO) only 10 h after the accident, in spite of the high risk of haemorrhage. The patient was stabilized within 60 min and transferred to the intensive care unit. He was weaned off ECMO after 51 h. He had no haemorrhagic complications, spent 3 weeks in the intensive care unit, and has made a good recovery.

Post-pneumonectomy video-assisted thoracoscopic bullectomy using extra-corporeal membrane oxygenation.

We describe a case of a patient who, 14 years after a pneumonectomy, required surgery for a life-threatening air-leak following accidental intubation of an emphysematous bulla in his remaining lung. To facilitate treatment by video-assisted thoracoscopic surgery, veno-venous extra-corporeal membrane oxygenation was employed.

Spallation performance of extracorporeal membrane oxygenation tubing.

During the prolonged roller pump use of extracorporeal membrane oxygenation (ECMO), tubing wear generates spallation. The spallation performance of Tygon S-65-HL was measured and compared with a potential new ECMO tubing, LVA (Portex 800-500-575). Spallation was measured by on-line laser diode particle counting (HIAC) during simulated ECMO. The effects of differing levels of occlusion and pump speed were examined, as was the effect of spallation over time. The spallation produced by Tygon S-65-HL was less than that seen with LVA during 24 h of simulated ECMO (p < 0.001), and after 72 h had fallen almost to zero. Spallation with Tygon tubing increases with increasing pump speed and decreases over time. There appears to be only a weak correlation with occlusion, which is surprising. The spallation performance of Tygon S-65-HL was variable and under some conditions exceeded that of LVA. Overall, however, Tygon S-65-HL produced less spallation than LVA. Therefore, LVA cannot be recommended for clinical ECMO use.

Modifying a venovenous extracorporeal membrane oxygenation circuit to reduce recirculation.

Lung rest is the primary goal of venovenous extracorporeal membrane oxygenation for severe acute respiratory failure. To achieve this there has to be adequate extracorporeal flow. This can be achieved by a two-cannula technique in most cases. In some cases, extra flow is either not achievable or causes excessive recirculation. We report 8 patients in whom we achieved adequate blood and oxygen delivery using a three-cannula technique. Five patients survived (62.5%).

Tubing failure during prolonged roller pump use: a laboratory study.

Little is known about the mechanical forces acting on extracorporeal circuit tubing with prolonged roller pump use during extracorporeal membrane oxygenation (ECMO). We examined the time to tubing rupture of three different materials during actual roller pump use, mean and standard deviation (SD) (SD shown in parentheses): Tygon (control) 243.7 h (175.4); LVA 121 h (14.3); and SRT 6.6 h (2.1). Failure times for both LVA and SRT were significantly different from the control (paired t-test, p = 0.02 and p < 0.001, respectively). The minimum failure times for Tygon and LVA were 99 and 101 h, respectively. We then examined Tygon under conditions of pure compression, demonstrating that even after 3.67 million compression cycles at full occlusion crack formation did not occur. If the tubing was over-occluded, cracks appeared within 24 h. Scanning electron microscopy of Tygon, which has been used during clinical ECMO, and the failure pattern during destruction testing demonstrate that shear stress and compression coexist during clinical ECMO. Use of under-occlusive pump settings could improve tubing life.

A porcine model of prolonged closed chest venovenous extracorporeal membrane oxygenation.

The sheep has been the standard laboratory animal for extracorporeal membrane oxygenation (ECMO) research for many years and has proven to be an invaluable and reliable model. However the coagulation system of the sheep is significantly different from humans. These differences make it difficult to investigate the coagulative and inflammatory response to ECMO in sheep. The pig has a very similar coagulation system to humans and therefore makes a more appropriate model. We describe a porcine model of prolonged (48 hours) closed chest venovenous (VV) ECMO that we developed to investigate the inflammatory and coagulative response to different ECMO tubing materials. This model could be used to investigate any aspect of venovenous ECMO.

The inflammatory and coagulative response to prolonged extracorporeal membrane oxygenation.

Extracorporeal circulation is used therapeutically during renal dialysis, cardiopulmonary bypass (CPB), and extracorporeal membrane oxygenation (ECMO). All of these procedures result in activation of the body's natural defense mechanisms against "nonself" and foreign invasion. The prolonged duration of ECMO compared with other applications and the absence of hypothermia, hemodilution, ischemia/reperfusion, and protamine administration make the host response to ECMO subtly distinct. In this review, the host response to ECMO is discussed and contrasted to CPB. The use of aprotinin and other response modifiers is also considered.