Extracorporeal membrane oxygenation in adults with severe respiratory failure: a multi-center database. Intensive Care Med. 2009;35:2105-2114. [PMID: 19768656 DOI: 10.1007/s00134-009-1661-7]

Lessons learned from airway pressure release ventilation

BACKGROUND

The aim of this article is to review a single institution's experience with airway pressure release ventilation (APRV) with respect to safety, complications, and efficacy at correcting hypercarbia and hypoxemia.

METHODS

Patients transitioned from either volume- or pressure-targeted ventilation to APRV in a university hospital surgical intensive care unit were retrospectively reviewed. Patients whose ventilator strategy started with APRV were excluded. Abstracted data included age, sex, diagnosis, ventilation parameters, indication for altering the ventilator strategy, laboratory values, and ventilator-associated complications. Data before and after transitioning to APRV were compared using a two-tailed unpaired t test or χ2 test as appropriate; significance assumed for p ≤ 0.05.

RESULTS

Patient mix (n = 38) was 43% trauma, 32% sepsis, 8% cardiac surgery, 12% vascular surgery, and 5% other. Transitioning to APRV was undertaken most often for hypoxemia (88%) and less frequently for hypercarbia (12%). The mean time to correct hypoxemia (SA(O2) >92%) was 7 minutes ± 4 minutes, while the mean time to correct P(CO2) (P(CO2) ≤40 mm Hg) was 42 minutes ± 7 minutes. The mean time to maximal CO2 clearance was 66 minutes ± 12 minutes. The mean minute ventilation decreased on APRV by 3.3 L/min ± 0.9 L/min but achieved superior CO2 clearance and oxygenation. The mean time to FIO2 ≤0.6 was 5.2 hours ± 0.9 hours. Four of the 38 patients developed a pneumothorax. Ninety-seven percent of patients on APRV who were transported out of the intensive care unit using bag-valve ventilation (with appropriate positive end-expiratory pressure valve settings) with P(high) ≥20 cm H2O developed hypoxemia within 5 minutes. Hundred percent of patients with a P(high) ≤20 cm H2O were safely hand ventilated during transport without developing hypoxemia.

CONCLUSIONS

APRV is a safe mode of ventilation for hypoxemic or hypercarbic respiratory failure. Improvements in PO2 and PCO2 are achieved at lower minute ventilations than with volume- or pressure-targeted modes.

LEVEL OF EVIDENCE

III.

Extracorporeal membrane oxygenation for 2009 influenza A(H1N1) severe respiratory failure in Japan

Purpose

To evaluate procedures and outcomes of extracorporeal membrane oxygenation (ECMO) therapy applied to 2009 influenza A(H1N1) severe respiratory failure patients in Japan.

Methods

This observational study used database information about adults who received ECMO therapy for H1N1-related severe respiratory failure from April 1, 2010 to March 31, 2011.

Results

Fourteen patients from 12 facilities were enrolled. Anti-influenza drugs were used in all cases. Before the start of ECMO, the lowest PaO₂/FiO₂ was median (interquartile) of 50 (40–55) mmHg, the highest peak inspiratory pressure was 30 (29–35) cmH₂O, and mechanical ventilation had been applied for at least 7 days in 5 patients. None of the facilities had extensive experience with ECMO for respiratory failure (6 facilities, no previous experience; 5 facilities, one or two cases annually). The blood drainage cannula was smaller than 20 Fr. in 10 patients (71.4 %). The duration of ECMO was 8.5 (4.0–10.8) days. The duration of each circuit was only 4.0 (3.2–5.3) days, and the ECMO circuit had to be renewed 19 times (10 cases). Thirteen patients (92.9 %) developed adverse events associated with ECMO, such as oxygenator failure, massive bleeding, and disseminated intravascular coagulation. The survival rate was 35.7 % (5 patients).

Conclusion

ECMO therapy for H1N1-related severe respiratory failure in Japan has very poor outcomes, and most patients developed adverse events. However, this result does not refute the effectiveness of ECMO. One possible cause of these poor outcomes is the lack of satisfactory equipment, therapeutic guidelines, and systems for patient transfer to central facilities.

Expanded resources through utilization of a primary care giver extracorporeal membrane oxygenation model

Extracorporeal membrane oxygenation (ECMO) is a long-term extracorporeal support for critically ill patients with life-threatening compromises in cardiac and/or respiratory function. The unpredictability of ECMO resources for a large pediatric and adult population prompted a need for the ability to respond to significant fluctuations in the volume of patients on ECMO. Through multidisciplinary collaboration, the Primary Care Giver (PCG) ECMO Staffing Model was developed to accommodate unpredictable fluctuations in ECMO activity and to maintain flexibility and fiscal responsibility in turbulent economic times. Advancements in extracorporeal technology supported the opportunity to develop a safe and extended staffing model for ECMO. Combining the use of a centrifugal pump system with specialized and experienced cardiovascular intensive care nurses and the ECMO specialist team provided a milieu for education and training to support the new staffing model. The PCG ECMO model provides a safe, flexible, and fiscally responsible staffing model for variable ECMO activity.

Extracorporeal life support: first year of experience implementing the technique in Slovenia

Extracorporeal life support (ELS) is emerging as a standard treatment option for acute respiratory and/or cardiac failure. In this article we describe our first year of experience with ELS activity in adult medical patients in our center. Veno-venous extracorporeal membrane oxygenation (VV ECMO) support was applied in cases of severe acute respiratory distress syndrome (ARDS) not responsive to conventional treatments. The use of veno-arterial (VA) ECMO support was reserved for cases of cardiac shock refractory to standard treatment and cardiac arrests not responding to conventional resuscitation. A total of 19 patients were treated with ELS during the first year of activity. Eight of these received VV ECMO for ARDS of various etiologies, with a survival rate of 63%. Eleven patients received VA ECMO support due to cardiac failure (2 post-resuscitation). Survival in this group was 45%. We report our results, including complications and organizational issues that we encountered, and describe protocol improvements developed over the short period of time since ELS treatment has been implemented in our center.

Nonconventional support of respiration

PURPOSE OF REVIEW

Several alternative treatments have been proposed to decrease mortality of patients with acute respiratory distress syndrome (ARDS). We will discuss most recent trials and meta-analysis studies on nonconventional ventilatory and pharmacological treatments of ARDS patients.

RECENT FINDINGS

Nonconventional ventilatory treatments such as prone positioning, high frequency oscillatory ventilation (HFOV), and extracorporeal membrane oxygenation (ECMO) aim to restore gas exchange while further decreasing ventilator induced lung injury. Though randomized trials failed to prove survival benefits with the use of prone positioning or HFOV, recent meta-analyses have shown, for both treatments, a decrease in mortality in the subpopulation of more severe ARDS patients. In a randomized controlled trial, referral of ARDS patients in a center with experience on ECMO was associated with an improved survival rate. Promising results come from new miniaturized extracorporeal techniques optimized for effective CO(2) removal from low blood flow. These techniques should allow early application of superprotective ventilator strategies. Pharmacological treatments such as neuromuscular blocking and intravenous β2 agonist may be effective in specific times and subsets of patients.

SUMMARY

Existing data suggest that some of the available nonconventional treatments may be effective in more severe ARDS patients. New techniques and drugs that should facilitate prevention or healing of lung injury are under investigation.

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.

Severe imported malaria in an intensive care unit: a review of 59 cases

BACKGROUND

In view of the close relationship of Portugal with African countries, particularly former Portuguese colonies, the diagnosis of malaria is not a rare thing. When a traveller returns ill from endemic areas, malaria should be the number one suspect. World Health Organization treatment guidelines recommend that adults with severe malaria should be admitted to an intensive care unit (ICU).

METHODS

Severe cases of malaria in patients admitted to an ICU were reviewed retrospectively (1990-2011) and identification of variables associated with in-ICU mortality performed. Malaria prediction score (MPS), malaria score for adults (MSA), simplified acute physiology score (SAPSII) and a score based on WHO's malaria severe criteria were applied. Statistical analysis was performed using StataV12.

RESULTS

Fifty nine patients were included in the study, all but three were adults; 47 (79,6%) were male; parasitaemia on admission, quantified in 48/59 (81.3%) patients, was equal or greater than 2% in 47 of them (97.9%); the most common complications were thrombocytopaenia in 54 (91.5%) patients, associated with disseminated intravascular coagulation (DIC) in seven (11.8%), renal failure in 31 (52.5%) patients, 18 of which (30.5%) oliguric, shock in 29 (49.1%) patients, liver dysfunction in 27 (45.7%) patients, acidaemia in 23 (38.9%) patients, cerebral dysfunction in 22 (37.2%) patients, 11 of whom with unrousable coma, pulmonary oedema/ARDS in 22 (37.2%) patients, hypoglycaemia in 18 (30.5%) patients; 29 (49.1%) patients presented five or more dysfunctions. The case fatality rate was 15.2%. Comparing the four scores, the SAPS II and the WHO score were the most sensitive to death prediction. In the univariate analysis, death was associated with the SAPS II score, cerebral malaria, acute renal and respiratory failure, DIC, spontaneous bleeding, acidosis and hypoglycaemia. Age, partial immunity to malaria, delay in malaria diagnosis and the level of parasitaemia were not associated with death in this cohort.

CONCLUSION

Severe malaria cases should be continued monitored in the ICUs. SAPS II and the WHO score are good predictors of mortality in malaria patients, but other specific scores deserve to be studied prospectively.

Trends in and perspectives on extracorporeal membrane oxygenation for severe adult respiratory failure

Various approaches such as ventilator management involving lung-protective ventilation, corticosteroids, prone positioning, and nitric oxide have failed to maintain sufficient lung oxygenation or appropriate ventilation competence in very severe acute respiratory distress syndrome (ARDS). Extracorporeal membrane oxygenation (ECMO) has been aggressively introduced for such patients, although in only a few institutions. The clinical usefulness of ECMO in a large-scale multicenter study (CESAR trial, 2009) and continued development/improvement of ECMO devices have facilitated performance of ECMO, with further increase in the number of institutions adopting ECMO therapy. Clinical usefulness of ECMO was documented in many cases of severe ARDS secondary to influenza A (H1N1) 2009 infection. ECMO requires establishment of an appropriate management system to minimize fatal complications (e.g., hemorrhage), which requires a multidisciplinary team. This, in combination with a new technique, interventional lung assist, will further extend the indications for ECMO. ECMO can be expected to gain importance as a respiratory support technique.

Superimposed high-frequency jet ventilation combined with continuous positive airway pressure/assisted spontaneous breathing improves oxygenation in patients with H1N1-associated ARDS

Background

Numerous cases of swine-origin 2009 H1N1 influenza A virus (H1N1)-associated acute respiratory distress syndrome (ARDS) bridged by extracorporeal membrane oxygenation (ECMO) therapy have been reported; however, complication rates are high. We present our experience with H1N1-associated ARDS and successful bridging of lung function using superimposed high-frequency jet ventilation (SHFJV) in combination with continuous positive airway pressure/assisted spontaneous breathing (CPAP/ASB).

Methods

We admitted five patients with H1N1 infection and ARDS to our intensive care unit. Although all patients required pure oxygen and controlled ventilation, oxygenation was insufficient. We applied SHFJV/CPAP/ASB to improve oxygenation.

Results

Initial PaO₂/FiO₂ ratio prior SHFJV was 58-79 mmHg. In all patients, successful oxygenation was achieved by SHFJV (PaO₂/FiO₂ ratio 105-306 mmHg within 24 h). Spontaneous breathing was set during first hours after admission. SHFJV could be stopped after 39, 40, 72, 100, or 240 h. Concomitant pulmonary herpes simplex virus (HSV) infection was observed in all patients. Two patients were successfully discharged. The other three patients relapsed and died within 7 weeks mainly due to combined HSV infection and in two cases reoccurring H1N1 infection.

Conclusions

SHFJV represents an alternative to bridge lung function successfully and improve oxygenation in the critically ill.

Use of extracorporeal life support in adults with severe acute respiratory failure

Extracorporeal membrane oxygenation (ECMO) is a recognized and accepted therapeutic option in the treatment of neonatal and pediatric respiratory failure. However, early studies in adults did not demonstrate a survival benefit associated with the utilization of ECMO for severe acute respiratory failure. Despite this historical lack of benefit, use of ECMO in adult patients has seen a recent resurgence. Local successes and a recently published randomized trial have both demonstrated promising results in an adult population with high baseline mortality and limited therapeutic options. This article will review the history of ECMO use for respiratory failure; investigate the driving forces behind the latest surge in interest in ECMO for adults with refractory severe acute respiratory failure; and describe potential applications of ECMO that will likely increase in the near future.

Extracorporeal membrane oxygenation in awake patients as bridge to lung transplantation

RATIONALE

The use of extracorporeal membrane oxygenation (ECMO) in patients who are awake and spontaneously breathing may represent a novel bridging strategy toward lung transplantation (LuTx).

OBJECTIVES

To evaluate the outcomes of patients treated with the "awake ECMO" concept as bridge to transplantation.

METHODS

We performed a retrospective, single-center, intention-to-treat analysis of consecutive LuTx candidates with terminal respiratory or cardiopulmonary failure receiving awake ECMO support. The outcomes were compared with a historical control group of patients treated with conventional mechanical ventilation (MV group) as bridge to transplant.

MEASUREMENTS AND MAIN RESULTS

Twenty-six patients (58% female; median age, 44 yr; range, 23-62) were included in the awake ECMO group and 34 patients (59% female; median age, 36 yr; range, 18-59) in the MV group. The duration of ECMO support or MV, respectively, was comparable in both groups (awake ECMO: median, 9 d; range, 1-45. MV: median, 15 d; range, 1-71; P = 0.25). Six (23%) of 26 patients in the awake ECMO group and 10 (29%) of 34 patients in the MV group died before a donor organ was available (P = 0.20). Survival at 6 months after LuTx was 80% in the awake ECMO group versus 50% in the MV group (P = 0.02). Patients in the awake ECMO group required shorter postoperative MV (P = 0.04) and showed a trend toward a shorter postoperative hospital stay (P = 0.06).

CONCLUSIONS

ECMO support in patients who are awake and nonintubated represents a promising bridging strategy, which should be further evaluated to determine its role in patients with end-stage lung disease awaiting LuTx.

Extracorporeal membrane oxygenation cannulation trends for pediatric respiratory failure and central nervous system injury

BACKGROUND

Guidelines regarding arterial cannula site and cannula site-specific risks of central nervous system (CNS) injury for pediatric patients requiring extracorporeal membrane oxygenation (ECMO) support are lacking. We reviewed cannulation trends for pediatric respiratory failure and evaluated CNS complication rates by cannulation site and mode of support.

METHODS

The Extracorporeal Life Support Organization (ELSO) registry was queried for all pediatric respiratory failure patients <18 years treated from 1993-2007. The primary outcome was radiographic evidence of CNS injury.

RESULTS

Venoarterial (VA) support was used in 62% of 2617 ECMO runs. The carotid artery was used in 93% of VA patients. Femoral artery use increased in patients >5 years of age and >20 kg. Venovenous (VV) ECMO was used in >50% of children >10 years. No significant difference was identified in CNS injury between carotid and femoral cannulation in any age group but the femoral group was small (4.4%). VA support was independently associated with increased odds of CNS injury compared to VV cannulation (OR, 1.6).

CONCLUSION

VA ECMO is the most common mode of support in pediatric respiratory failure patients. Although no significant difference in CNS injury was noted between carotid and femoral artery cannulation, the odds of injury were significantly higher than VV support.

Extracorporeal Membrane Oxygenation: Coming to an ICU near you

Extra-corporeal membrane oxygenation has come of age after publication of the CESAR trial and the experience of its use during the 2009 H1N1 influenza pandemic, showing its increasing benefit for the treatment of hypoxaemic respiratory failure and combined cardiovascular and respiratory failure, including post-cardiac arrest. The article reviews the evidence for this technology and its indications, modes, methods, complications and recent advances. The authors suggest that ECMO will be used increasingly, even in non-cardiac specialist centres.

Defining risk for infectious complications on extracorporeal life support

BACKGROUND/PURPOSE

Little is known about potentially modifiable risk factors associated with infectious complications (IC) acquired during extracorporeal life support (ECLS).

PATIENTS AND METHODS

The Extracorporeal Life Support Organization registry was accessed, and data on patient demographics, run characteristics, infections, and outcomes were collected. Patients who developed IC while on ECLS were compared to those that did not. Regression analysis was performed. Results are expressed as odds ratios, with P < .05 considered significant.

RESULTS

Infectious complications developed in 10.2% of 38,661 patients and was associated with increased odds of death. Risk factors for IC included increasing age, diagnosis, more remote decade, complications, presence of multiple complications, and ECLS mode. The risk of IC increased with the number of complications (P < .001). Patients with positive cultures before ECLS also had increased odds of IC (OR 2.12, 95% CI 1.92-2.34, P < .001). Those with IC were more likely to have cultures grow aggressive organisms (non-lactose fermenting gram negative rods, methicillin resistant Staphylococcus aureus, and fungi).

CONCLUSIONS

Strategies to reduce IC while on ECLS should be aimed at prevention of complications and treatment of pre-existing infections. Future studies should address whether broader spectrum antibiotic prophylaxis and/or empiric coverage for suspected sepsis is indicated in ECLS patients.

Extracorporeal membrane oxygenation for ARDS in adults

A 41-year-old woman presents with severe community-acquired pneumococcal pneumonia. Chest radiography reveals diffuse bilateral infiltrates, and hypoxemic respiratory failure develops despite appropriate antibiotic therapy. She is intubated and mechanical ventilation is initiated with a volume- and pressure-limited approach for the acute respiratory distress syndrome (ARDS). Over the ensuing 24 hours, her partial pressure of arterial oxygen (Pao2) decreases to 40 mm Hg, despite ventilatory support with a fraction of inspired oxygen (Fio2) of 1.0 and a positive end-expiratory pressure (PEEP) of 20 cm of water. She is placed in the prone position and a neuromuscular blocking agent is administered, without improvement in her Pao2. An intensive care specialist recommends the initiation of extracorporeal membrane oxygenation (ECMO).

Acquired von Willebrand syndrome in patients with extracorporeal life support (ECLS)

PURPOSE

Extracorporeal life support (ECLS) is used for patients with refractory heart failure with or without respiratory failure. This temporary support is provided by blood pumps which are connected to large vessels. Bleeding episodes are a typical complication in patients with ECLS. Recently, several studies illustrated that acquired von Willebrand syndrome (AVWS) can contribute to bleeding tendencies in patients with long-term ventricular assist devices (VAD). AVWS is characterized by loss of the high molecular weight (HMW) multimers of von Willebrand factor (VWF) as a result of high shear stress and leads to impaired binding of VWF to platelets and to subendothelial matrix. Since ECLS and VAD share several features, we investigated patients with ECLS for AVWS.

METHODS

We analyzed 32 patients with ECLS and 19 of them without support. To diagnose AVWS, ratios of ristocetin cofactor activity (VWF:RCo) and collagen binding capacity (VWF:CB) to VWF antigen (VWF:Ag) were employed in conjunction with multimeric analysis.

RESULTS

Reduced VWF:RCo/VWF:Ag ratios were identified in 28 ECLS patients. Furthermore, VWF:CB/VWF:Ag ratios were decreased in 31 patients. HMW multimers of VWF were missing in the same 31 patients. Thus, 31 of 32 ECLS patients presented with AVWS. Twenty-two of the 32 patients suffered from bleeding complications. Without support, AVWS was not detectable in any analyzed patient.

CONCLUSION

Our data indicate that AVWS is a typical disorder in patients with ECLS. We hypothesize that AVWS could contribute to aggravation of bleeding tendencies in ECLS patients.

The Italian ECMO network experience during the 2009 influenza A(H1N1) pandemic: preparation for severe respiratory emergency outbreaks

PURPOSE

In view of the expected 2009 influenza A(H1N1) pandemic, the Italian Health Authorities set up a national referral network of selected intensive care units (ICU) able to provide advanced respiratory care up to extracorporeal membrane oxygenation (ECMO) for patients with acute respiratory distress syndrome (ARDS). We describe the organization and results of the network, known as ECMOnet.

METHODS

The network consisted of 14 ICUs with ECMO capability and a national call center. The network was set up to centralize all severe patients to the ECMOnet centers assuring safe transfer. An ad hoc committee defined criteria for both patient transfer and ECMO institutions.

RESULTS

Between August 2009 and March 2010, 153 critically ill patients (53% referred from other hospitals) were admitted to the ECMOnet ICU with suspected H1N1. Sixty patients (48 of the referred patients, 49 with confirmed H1N1 diagnosis) received ECMO according to ECMOnet criteria. All referred patients were successfully transferred to the ECMOnet centers; 28 were transferred while on ECMO. Survival to hospital discharge in patients receiving ECMO was 68%. Survival of patients receiving ECMO within 7 days from the onset of mechanical ventilation was 77%. The length of mechanical ventilation prior to ECMO was an independent predictor of mortality.

CONCLUSIONS

A network organization based on preemptive patient centralization allowed a high survival rate and provided effective and safe referral of patients with severe H1N1-suspected ARDS.

Addition of acetylsalicylic acid to heparin for anticoagulation management during pumpless extracorporeal lung assist

Pump-driven extracorporeal membrane oxygenation (ECMO) or pumpless arterio-venous interventional lung assist (iLA) is associated with possible complications, mainly consisting of bleeding or thrombosis/clotting by cellular deposits on the membrane or extracorporeal circuit surfaces, which may reduce gas-exchange capacity. In this study, we report our experiences with the addition of low-dose acetylsalicylic acid (ASA 1.5 mg/kg body weight/d) to heparin for anticoagulation of a pumpless low-resistance gas-exchange membrane (Novalung GmbH, Talheim, Germany). We assessed changes in coagulation parameters and the demand for transfusion of blood components. Furthermore, we compared the function of the artificial membranes (oxygen transfer and capacity of CO2 removal) of the ASA group (n = 15) with that of a matched-pair control group treated with heparin alone. The mean duration of iLA treatment was 6.6 ± 3.7 days. The addition of ASA did not increase bleeding activity or the demand for transfusion. Relative changes of CO2 removal on day 3 expressed as a percentage in the ASA group were (mean value) -11.8% in comparison with control (-3.0%, p = 0.266), but the relative amount of oxygen transfer tended to be increased in the ASA group (+3.9%) and to be decreased in the control group (-14.7%, p = 0.214). PaO2/FiO2 ratio was significantly improved in the ASA group compared with the control group at day 5. The use of membranes per patient (membrane/patient ratio) tended to be decreased in patients treated with ASA (1.12 ± 0.34) in comparison with control (1.33 ± 0.62, p = 0.157). In the ASA group, one patient died due to multiple organ failure, whereas in the control group, five patients died. We conclude that supplementation of low-dose ASA during pumpless extracorporeal lung support is safe and might preserve the function of oxygen transfer.

Extracorporeal membrane oxygenation in the context of the 2009 H1N1 influenza A pandemic

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) incorporates surgical techniques as adjuncts in the management of refractory respiratory dysfunction. For many years, its primary application was for support of neonatal infants in cardiorespiratory failure. As the 2009 H1N1 influenza A pandemic developed, more reports came in of severe respiratory dysfunction and even death that seemed to be occurring preferentially in younger adults. Centers with the capability began to use ECMO to salvage these patients.

RESULTS

The H1N1 virus is a subtype of influenza A. The hemagglutinin receptor binding is similar to that of the seasonal influenza virus, but 2009 H1N1 also binds to α2,3-linked receptors, which are found in the conjunctivae, distal airways, and alveolar pneumocytes. Influenza viruses elude host immune responses through drift and shift in the hemagglutinin (HA) and neuraminidase (NA) proteins. The incubation period ranges from 1-7 days. The majority of patients present with fever and cough, but a broad spectrum of clinical syndromes has been reported, and laboratory testing remains the mainstay of diagnosis. Most patients recover within a week without treatment. The H1N1 virus remains largely sensitive to the NA inhibitors but is resistant to the matrix protein-2 inhibitors. Extracorporeal membrane oxygenation provides continuous pulmonary (and sometimes cardiac) support and minimizes ventilator-induced lung injury. The potential for life-threatening complications is high. In 2009, in the Conventional Ventilation or ECMO for Severe Adult Respiratory Failure (CESAR) randomized trial of ECMO, the overall survival rate was 63% in the ECMO group compared with 47% in the control group (p = 0.03). Similar studies have been reported from Australia and New Zealand, Canada, and France.

CONCLUSIONS

Supportive management is continued along with ECMO. Antiviral drugs and antimicrobial agents should be given as appropriate, as should nutritional support. Volume management should be used. Ventilator settings should be reduced as ECMO support allows, with a goal of reducing airway pressures, ventilator rate, and FiO(2). Complications of ECMO are common. Bleeding, the most common, can result in death, especially if it occurs intracranially.

[Severe cases of A(H1N1)v2009 infection in Réunion Island in 2009 and 2010]

Dans l’hémisphère sud, La Réunion est la sentinelle des infections survenant préférentiellement au cours de l’hiver austral, susceptibles de gagner quelques mois plus tard l’hémisphère nord, telle l’infection à A(H1N1)v2009. Nous rapportons les caractéristiques des patients admis en 2009 et 2010 dans notre service de réanimation principalement pour détresse respiratoire aiguë, à la suite d’une infection à A(H1N1)v2009. Les données démographiques, cliniques, biologiques, ainsi que les traitements et le devenir des patients admis pour infection virale à A(H1N1)v2009 exclusivement confirmée par RT-PCR ont été recueillis de façon prospective. Au cours des années 2009 et 2010, 25 patients ont répondu aux critères définis d’infection à A(H1N1)v2009. L’âge médian était de 40,4 (±17,4) ans. La plupart d’entre eux (22/25) présentaient des facteurs de comorbidité: pathologies chroniques, surpoids ou obésité, grossesse, trisomie. Les principaux motifs d’admission en réanimation ont été les pneumonies virales avec tableau de syndrome de détresse respiratoire aiguë. Le recours à la ventilation artificielle a été nécessaire chez 22 des 25 patients, avec recours à des méthodes sophistiquées et réservées à quelques centres au niveau national, telles que les techniques d’oxygénation extracorporelle (ECMO) ou ventilation à haute fréquence (HFO). Au cours des deux années, 12 décès (48 %) sont survenus essentiellement dans des tableaux de défaillance multiviscérale. Au cours des hivers et automnes australs 2009 et 2010 et pendant une période de plusieurs semaines, l’infection à A(H1N1) v2009 a entraîné une surcharge d’activité notable dans les services de réanimation de La Réunion. L’échec de la campagne de vaccination, notamment des personnes à risques, a eu pour conséquence la survenue de nouveaux cas graves en 2010, notamment parmi les personnes à risques. Le recueil de ces données peut aider à la planification et à l’anticipation de la prise en charge d’autres épidémies grippales.

Extra corporal membrane oxygenation in general thoracic surgery: a new single veno-venous cannulation

Extracorporeal membrane oxygenation (ECMO) is used in severe respiratory failure to maintain adequate gas exchange. So far, this technique has not been commonly used in general thoracic surgery. We present a case using ECMO for peri-operative airway management for pulmonary resection, using a novel single-site, internal jugular, veno-venous ECMO cannula.

Extracorporeal membrane oxygenation for severe ARDS in pregnant and postpartum women during the 2009 H1N1 pandemic

PURPOSE

To describe the technical challenges, efficacy, complications and maternal and infant outcomes associated with extracorporeal membrane oxygenation (ECMO) for severe adult respiratory distress syndrome (ARDS) in pregnant or postpartum patients during the 2009 H1N1 pandemic.

METHODS

Twelve critically ill pregnant and postpartum women were included in this retrospective observational study on the application of ECMO for the treatment of severe ARDS refractory to standard treatment. The study was conducted at seven tertiary hospitals in Australia and New Zealand.

RESULTS

Of the 12 patients treated with ECMO, 7 (58%) were pregnant and 5 (42%) were postpartum. Their median (interquartile range [IQR]) age was 29 (26-33) years, 6 (50%) were obese. Two patients were initially treated with veno-arterial (VA) ECMO. All others received veno-venous (VV) ECMO with one or two drainage cannulae. ECMO circuit-related complications were rare, circuit change was needed in only two cases and there was no sudden circuit failure. On the other hand, bleeding was common, leading to relatively large volumes of packed red blood cell transfusion (median [IQR] volume transfused was 3,499 [1,451-4,874] ml) and was the main cause of death (three cases). Eight (66%) patients survived to discharge and seven were ambulant, with normal oxygen saturations. The survival rate of infants whose mothers received ECMO was 71% and surviving infants were discharged home with no sequelae.

CONCLUSIONS

The use of ECMO for severe ARDS in pregnant and postpartum women was associated with a 66% survival rate. The most common cause of death was bleeding. Infants delivered of mothers who had received ECMO had a 71% survival rate and, like their mothers, had no permanent sequelae at hospital discharge.

Improving oxygenator performance using computational simulation and flow field-based parameters

Current goals in the development of oxygenators are to reduce extrinsic surface contact area, thrombus formation, hemolysis, and priming volume. To achieve these goals and provide a favorable concentration gradient for the gas exchange throughout the fiber bundle, this study attempts to find an optimized inlet and outlet port geometry to guide the flow of a hexagonal-shaped oxygenator currently under development. Parameters derived from numerical flow simulations allowed an automated quantitative evaluation of geometry changes of flow distribution plates. This led to a practical assessment of the quality of the flow. The results were validated qualitatively by comparison to flow visualization results. Two parameters were investigated, the first based on the velocity distribution and the second calculated from the residence time of massless particles representing erythrocytes. Both approaches showed significant potential to improve the flow pattern in the fiber bundle, based on one of the parameters of up to 66%. Computational fluid dynamics combined with a parameterization proved to be a powerful tool to quickly improve oxygenator designs.

Extracorporeal membrane oxygenation for pediatric respiratory failure: Survival and predictors of mortality

OBJECTIVE

The last multicentered analysis of extracorporeal membrane oxygenation in pediatric acute respiratory failure was completed in 1993. We reviewed recent international data to evaluate survival and predictors of mortality.

DESIGN

Retrospective case series review.

SETTING

The Extracorporeal Life Support Organization Registry, which includes data voluntarily submitted from over 115 centers worldwide, was queried. The work was completed at the Division of Pediatric Critical Care, Department of Pediatrics, Primary Children's Medical Center, University of Utah, Salt Lake City, UT.

SUBJECTS

Patients aged 1 month to 18 yrs supported with extracorporeal membrane oxygenation for acute respiratory failure from 1993 to 2007.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

There were 3,213 children studied. Overall survival remained relatively unchanged over time at 57%. Considerable variability in survival was found based on pulmonary diagnosis, ranging from 83% for status asthmaticus to 39% for pertussis. Comorbidities significantly decreased survival to 33% for those with renal failure (n = 329), 16% with liver failure (n = 51), and 5% with hematopoietic stem cell transplantation (n = 22). The proportion of patients with comorbidities increased from 19% during 1993 to 47% in 2007. Clinical factors associated with mortality included precannulation ventilatory support longer than 2 wks and lower precannulation blood pH.

CONCLUSIONS

Although the survival of pediatric patients with acute respiratory failure treated with extracorporeal membrane oxygenation has not changed, this treatment is currently offered to increasingly medically complex patients. Mechanical ventilation in excess of 2 wks before the initiation of extracorporeal membrane oxygenation is associated with decreased survival.

[Extracorporeal membrane oxygenation in acute respiratory distress syndrome after a liver transplant]

Extracorporeal membrane oxygenation (ECMO) is used in the treatment of severe respiratory failure that is potentially reversible. This mode of therapy reduces ventilator-associated lung injury. Although ECMO is costly and not free of complications, its early application by experienced multidisciplinary teams can improve survival. We report a case of acute respiratory distress syndrome in a patient who had received a liver transplant. Respiratory failure was unresponsive to conventional treatment and the patient required ECMO until recovery.

Retrieval of critically ill adults using extracorporeal membrane oxygenation: an Australian experience

PURPOSE

A retrieval program was developed in New South Wales (NSW), Australia to provide extracorporeal membrane oxygenation support (ECMO) for the safe transport of adults with severe, acute respiratory or cardiac failure. We describe the development and results of this program and the impact of the 2009 H1N1 epidemic on this service.

METHODS

An observational study of all patients who were retrieved on ECMO support in NSW, from March 1, 2007 to June 1, 2010, was carried out.

RESULTS

Forty adult patients were retrieved on ECMO support (median age 34 years). The indications for retrieval were respiratory in 38 patients (of whom 16 were confirmed or suspected H1N1 cases) and cardiac in 2 patients. Two other patients died after referral but before ECMO support could be established. Patients were transported by road (n = 26, 65%), medical retrieval jet (n = 10, 25%) and helicopter (n = 4, 10%). The median retrieval distance was 250 km (range 12-1,960 km). Thirty-four patients (85%) survived to hospital discharge. Survival for respiratory indications was 87% (33/38 patients) and 50% (1/2 patients) for cardiac indications. There were no deaths or major morbidity associated with these retrievals.

CONCLUSIONS

Patients with very severe respiratory failure, which was considered to preclude conventional ventilation for safe transfer to tertiary centres, were managed by an ECMO referral and retrieval program in NSW and had a high rate of survival. This program also enhanced the capacity of the state to respond to a surge in demand for ECMO support due to the H1N1 epidemic, although the role of ECMO in respiratory failure is not yet well defined.

Risk of circuit infection in septic patients on extracorporeal membrane oxygenation: a preliminary study

Extracorporeal membrane oxygenation (ECMO) is the ultimate treatment option to improve gas exchange and decrease the aggressiveness of mechanical ventilation in septic patients with uncontrolled severe lung failure. However, potential microbiological colonization of the artificial surfaces of membrane oxygenator (MO) remains a critical issue in patients with bacteremia. The current study investigates the risk of MO infection in 10 consecutive septic patients on long-term treatment with ECMO. The flushing fluids of all investigated MOs were sterile. After incubation with nutrient solution for 14 days in one MO Enterococci spp. were isolated. In the patient concerned, a diffuse, unaccountable bleeding diathesis had developed, which stopped after exchange of the MO. Analysis of clinical parameters showed that D dimers had increased and fibrinogen levels had decreased before exchange of this MO, but standard markers of infection had remained unremarkable. In conclusion, circuit infection may be a potential cause for unexplained clinical deterioration of patients on ECMO, which therefore should be considered as an indication for exchange of the device.

Extracorporeal membrane oxygenation for acute respiratory distress syndrome: is the configuration mode an important predictor for the outcome?

Extracorporeal membrane oxygenation (ECMO) is increasingly applied as rescue-therapy for patients with severe acute respiratory distress syndrome (ARDS). Here, we evaluate the effect of different configuration strategies (venovenous vs. venoarterial vs. veno-venoarterial) on the outcome. From 2006 to 2008, 30 patients received ECMO for severe ARDS. Patients were divided into three groups according to the configuration: veno-venous (vv; n = 11), venoarterial (va; n=8) or veno-venoarterial (vva; n = 11). Data were prospectively collected and endpoint was 30-day mortality. To identify independent risk factors, univariate analysis was performed for clinical parameters, such as age, body mass index, gender, configuration, low-pH, oxygenation index (pO(2)/FiO(2)) and underlying disease. Thirty-day mortality was 53% (n = 16) for all comers: 63% (n = 7) died in the vv-group, 75% (n = 6) in the va-group and 27% (n = 3) in the vva-group. Although univariate analysis could not rule out a significant predictor for the outcome, there was a trend visible to decreased mortality in the vva-group when compared to vv- and va-groups (27% vs. 63% vs. 75%; P = 0.057). ECMO provides a survival benefit in patients when considering a predicted mortality rate of 80% in ARDS. The configuration mode appears to impact the outcome as the veno-venoarterial appears to further improve the survival in this subset of patients.

Ventilatory and ECMO treatment of H1N1-induced severe respiratory failure: results of an Italian referral ECMO center

Background

Since the first outbreak of a respiratory illness caused by H1N1 virus in Mexico, several reports have described the need of intensive care or extracorporeal membrane oxygenation (ECMO) assistance in young and often healthy patients. Here we describe our experience in H1N1-induced ARDS using both ventilation strategy and ECMO assistance.

Methods

Following Italian Ministry of Health instructions, an Emergency Service was established at the Careggi Teaching Hospital (Florence, Italy) for the novel pandemic influenza. From Sept 09 to Jan 10, all patients admitted to our Intensive Care Unit (ICU) of the Emergency Department with ARDS due to H1N1 infection were studied. All ECMO treatments were veno-venous. H1N1 infection was confirmed by PCR assayed on pharyngeal swab, subglottic aspiration and bronchoalveolar lavage. Lung pathology was evaluated daily by lung ultrasound (LUS) examination.

Results

A total of 12 patients were studied: 7 underwent ECMO treatment, and 5 responded to protective mechanical ventilation. Two patients had co-infection by Legionella Pneumophila. One woman was pregnant. In our series, PCR from bronchoalveolar lavage had a 100% sensitivity compared to 75% from pharyngeal swab samples. The routine use of LUS limited the number of chest X-ray examinations and decreased transportation to radiology for CT-scan, increasing patient safety and avoiding the transitory disconnection from ventilator. No major complications occurred during ECMO treatments. In three cases, bleeding from vascular access sites due to heparin infusion required blood transfusions. Overall mortality rate was 8.3%.

Conclusions

In our experience, early ECMO assistance resulted safe and feasible, considering the life threatening condition, in H1N1-induced ARDS. Lung ultrasound is an effective mean for daily assessment of ARDS patients.

[Results of studies in critical care medicine in the year 2009 : update]

Critical care medicine plays an important role for the medical and economic success of hospitals. Knowledge and implementation of recent relevant studies are prerequisites for high quality intensive care medicine. The aim of the present manuscript is to present an overview of the most important publications in intensive care medicine in 2009 and comment on their clinical relevance. It has to be recognized that the cited studies are chosen according to the view of the authors. In 2009 many large randomized studies with high patient numbers were published. Main topics in 2009 were the therapy of lung failure, analgosedation and sepsis therapy. New trends are bedside echocardiography and telemedicine. Unfortunately, a magic bullet has not been identified last year. The focus is still on team education and guideline-assisted therapy.

Use of extracorporeal life support to support patients with acute respiratory distress syndrome due to H1N1/2009 influenza and other respiratory infections

A large proportion of critically ill H1N1/2009 patients with respiratory failure subsequently developed ARDS and, to date, about 400 patients receiving extracorporeal life support (ECLS) have been accounted for globally, with a reported survival rate from 63% to 79%. The survival rates of patients with ARDS due to non-H1N1/2009 infections are similar. There is no definite evidence to suggest that patient outcomes are changed by ECLS, but its use is associated with serious short-term complications. ECLS relies on an extracorporeal circuit, with extracorporeal membrane oxygenation (ECMO) and pumpless interventional lung assist (ILA) being the two major types employed in ARDS. Both have the potential to correct respiratory failure and related haemodynamic instability. There are only a very limited number of clinical trials to test either and, although ECLS has been used in treating H1N1/2009 patients with ARDS with some success, it should only be offered in the context of clinical trials and in experienced centres.

Extracorporeal membrane oxygenation in nonintubated patients as bridge to lung transplantation

We report on the use of veno-arterial extracorporeal membrane oxygenation (ECMO) as a bridging strategy to lung transplantation in awake and spontaneously breathing patients. All five patients described in this series presented with cardiopulmonary failure due to pulmonary hypertension with or without concomitant lung disease. ECMO insertion was performed under local anesthesia without sedation and resulted in immediate stabilization of hemodynamics and gas exchange as well as recovery from secondary organ dysfunction. Two patients later required endotracheal intubation because of bleeding complications and both of them eventually died. The other three patients remained awake on ECMO support for 18-35 days until the time of transplantation. These patients were able to breathe spontaneously, to eat and drink, and they received passive and active physiotherapy as well as psychological support. All of them made a full recovery after transplantation, which demonstrates the feasibility of using ECMO support in nonintubated patients with cardiopulmonary failure as a bridging strategy to lung transplantation.

Extracorporeal membrane oxygenation for severe influenza A (H1N1) acute respiratory distress syndrome: a prospective observational comparative study

PURPOSE

To compare characteristics, clinical evolution and outcome in adult patients with influenza A (H1N1) acute respiratory distress syndrome (ARDS) treated with or without extracorporeal membrane oxygenation (ECMO).

METHODS

A prospective observational study of patients treated in Marseille South Hospital from October 2009 to January 2010 for confirmed influenza A (H1N1)-related ARDS. Clinical features, pulmonary dysfunction and mortality were compared between patients treated with and without ECMO.

RESULTS

Of 18 patients admitted, 6 were treated with veno-venous and 3 with veno-arterial ECMO after median (interquartile, IQR) duration of mechanical ventilation of 10 (6-96) h. Six ECMO were initiated in a referral hospital by a mobile team, a median (IQR) of 3 (2-4) h after phone contact. Before ECMO, patients had severe respiratory failure with median (IQR) PaO₂ to FiO₂ ratio of 52 (50-60) mmHg and PaCO₂ of 85 (69-91) mmHg. Patients treated with or without ECMO had the same hospital mortality rate (56%, 5/9). Duration of ECMO therapy was 9 (4-14) days in survivors and 5 (2-25) days in non-survivors. Early improvement of PaO(2) to FiO₂ ratio was greater in ECMO survivors than non-survivors after ECMO initiation [295 (151-439) versus 131 (106-144) mmHg, p < 0.05]. Haemorrhagic complications occurred in four patients under ECMO, but none required surgical treatment.

CONCLUSIONS

ECMO may be an effective salvage treatment for patients with influenza A (H1N1)-related ARDS presenting rapid refractory respiratory failure, particularly when provided by a mobile team allowing early cannulation prior to transfer to a reference centre.