Extracorporeal Membrane Oxygenation

 

EXTRACORPOREAL MEMBRANE OXYGENATION TREATMENT

Extracorporeal Membrane Oxygenation Treatment and Outcomes within Varying Age Groups

Michelle R. Boswell

Southwest Baptist University

Abstract

Extracorporeal membrane oxygenation is a complex heart and lung machine that creates a man-made circulatory system to keep patients alive. There are many different medical diagnoses that can be treated with ECMO. ECMO can be used in premature neonates, pediatric patients, and adults up to sixty years of age. This paper will discuss the success rate of ECMO within varying age groups. Literature was used to come to these conclusions. The most success has been shown in pediatric patients. Adult patients have a lower success rate and therefore ECMO is a last resort treatment for them. ECMO has great risks associated with it. Many patients who are put on ECMO would otherwise have a very high chance of mortality. Some long term effects have been associated with ECMO treatment and the disease processes that the patients were being treated for. One study in Oslo, Norway showed that pediatric patients have the highest rate of survival after ECMO treatment (Wagner, Risnes, Abdelnoor, Karlsen, & Svennevig, 2008).  The outcome of the study was as follows: 50% of the neonatal patients in the study were discharged from the hospital, 71% of pediatric patients, and 40% of the adult patients.

Extracorporeal Membrane Oxygenation Treatment and Outcomes within Varying Age Groups

                                Extracorporeal membrane oxygenation (ECMO) is a method used to treat cardiac or respiratory failure when other methods are unsuccessful.  ECMO has been used for many years in intensive care units with neonatal and pediatric patients, but it has just recently started to be used more with adult patients (Gay, Ankney, Cochran, & Highland, 2005).   There are two different types of ECMO circuits, veno-venous and veno-arterial.  In both types, venous blood is drained through a large cannula into the ECMO machine itself and then returned to the patient (Gay, et al., 2008). In veno-venous it is returned to a vein and in veno-arterial ECMO, it is returned to the patient through an artery. Veno-venous is more often used with the adult patient (Gay, et al., 2008). Veno-venous ECMO is also called pulmonary ECMO because it assists the lungs with oxygenation. Veno-arterial ECMO is also called cardiac ECMO and used with cardiac patients since it pumps back to the body through an artery, it is also assisting the cardiac system (Wagner, et al., 2008). The 2008 study that Wagner and his colleagues performed showed that the length of time a patient is on ECMO can vary, and has not been shown to correlate with mortality rate.

Disease Process

                There are several different reasons a patient would be treated with ECMO. Some of the diagnoses for neonatal patients on ECMO include: persistent pulmonary hypertension of the neonate, meconium aspiration syndrome, sepsis or sepsis with pneumonia, congenital diaphragmatic hernia, congenital heart disease, and respiratory distress syndrome (Hamutcu, Nield, Garg, Keens, & Platzker, 2004).  Some diagnoses of the adult patient on ECMO are the same as the neonate. They may also include:  post lung transplantation, acute respiratory distress syndrome post-trauma, post cardiotomy failure, or post myocardial infarction (Wagner et al., 2008).  ECMO can also be used to keep a patient alive while trying to stabilize them during a code situation (Gonski, 2004). When ECMO is used, it reduces the amount of high oxygen concentrations as well as high peak inspiratory pressures that are associated with ventilator use (Gay, et al., 2005). This gives the lungs time to heal, because the ECMO machine is doing the work of the lungs by oxygenating the blood while reducing carbon dioxide levels in the blood.

Use of ECMO

                Some criterion has been established to decide when ECMO should be used to treat an adult patient. Gay, et al. found that these criteria include age, different ratios of pulmonary performance, and what quality of life patients are expected to have after the treatment (2005). Patients who have irreversible neurological damage, chronic systemic disease, or who are immunocompromised are not considered for ECMO (Gay, et al., 2005). Their quality of life is not expected to be high if they do survive, and their life expectancy is already severely decreased before treatment.

                What is the mortality rate with the use of ECMO? One study done in 2008 in Oslo, Norway tried to predict the outcomes of patients treated with ECMO (e.g. Wagner, et al.). They included various factors like age, gender, and other types of treatment that had been utilized prior to ECMO treatment. The outcome of the study was as follows: 50% of the neonatal patients in the study were discharged from the hospital, 71% of pediatric patients, and 40% of the adult patients (Wagner et al., 2008). The point of this study was that it is hard to predict the outcome of the patient placed on ECMO. For obvious reasons, adults have a lower success rate than other groups of patients. Adults just have a larger volume of blood to be taken out and re-circulated. Also, adults have hearts that have worked longer than neonatal or pediatric patients’ hearts. There were two factors found to correlate with mortality rate in this study, however. All three patients in the study who had intra-aortic balloon pumps prior to ECMO did not survive (Wagner, et al., 2008). These patients probably had less healthy valves than most of the other patients in the study. Also, in comparing patients who lived versus those who did not survive, serum creatinine levels were much lower in the surviving patients (Wagner, et al., 2008).  The report was conclusive in proving that age is a factor in ECMO treatment. For adult patients, ECMO is a last resort of treatment modality.

Complications

ECMO is not without risks. There can be complications that lead to mortality. Patients must take an anticoagulant during therapy and have their hemoglobin, hematocrit, and clotting time levels monitored (Gay, et al., 2005). Heparin therapy can lead to thrombocytopenia, as well as disseminated intravascular coagulation (Gay, et al., 2005). Also, the cannulas used for treatment are so large, that if one were to come out accidentally, it would be easy for a patient to hemorrhage.  Pulses distal to the insertion site of the cannula must be monitored for proficient circulation (Gay, et al., 2005). Patients on ECMO are also at risk for renal failure, so their intake and output must be monitored very carefully. If the patient’s kidneys do start to fail, a special filter attachment can be put on the ECMO machine to do dialysis as well (Gay, et al., 2005).

Research Studies

                One study done in 2004 in Los Angeles shows the sequelae, or long term effects of ECMO treatment (Hamutcu, et al.). Fifty children between the ages of ten and twelve were studied for pulmonary deficits related to their ECMO treatment as a neonate (Hamutcu, et al., 2004).  This group of children was compared to a control group of twenty-seven healthy children of the same ages. Different exercise regimens were performed by each group of children and their pulmonary functioning was measured. The children who had had ECMO treatment showed lung hyperinflation and airway obstruction at rest, decreased aerobic fitness, and lower arterial oxygen saturation (Hamutcu, et al., 2004).  Having a pulmonary issue severe enough to be treated with ECMO as a neonate, it is no surprise that these children are experiencing long term pulmonary effects. The question is, was it the ECMO treatment that caused these sequelae, or the disease for which the patient had to be placed on ECMO treatment? Whichever it may be, these children are living, and that is the most significant factor.

                ECMO is a treatment modality for which modern medicine is to thank. Neonatal patients to adult patients have benefitted from ECMO treatment. Pediatric patients have shown the highest success rate. It has been a treatment to rely on when other things, such as oscillating ventilators and nitric oxide are unsuccessful (Gonski, 2004).  Long term effects have been discovered after use of ECMO. The risks of ECMO can be fatal, but not having it as a treatment option could also be fatal for many patients as well. Although it is not the answer for every patient, it has saved numerous lives.

References

Gay, S., Ankney, N., Cochran, J., & Highland, K. (2005, July). Critical care challenges in the                    adult ECMO patient. Dimensions of Critical Care Nursing, 24(4), 157-164. Retrieved    July 13, 2009, from CINAHL Plus with Full Text database.

Gonski, Anna. (2004). A cutting edge technology grows up. Dream: The magazine of possibilities,   Children’s Hospital Boston. Retrieved July18, 2009 from http://www.childrenshospital.org/dream/DreamWin04/ecmo.html.

Hamutcu, R., Nield, T., Garg, M., Keens, T., & Platzker, A. (2004, November). Long-term pulmonary         sequelae in children who were treated with extracorporeal membrane oxygenation for neonatal   respiratory failure. Pediatrics, 114(5 Part 1), 1292-1296. Retrieved July 13, 2009, from CINAHL    Plus with Full Text database.

Wagner, K., Risnes, I., Abdelnoor, M., Karlsen, H., & Svennevig, J. (2008, March). Is it possible to             predict outcome in pulmonary ECMO? Analysis of pre-operative risk factors. Perfusion, 23(2),       95-99. Retrieved July 13, 2009, from CINAHL Plus with Full Text database.

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~ by nursemichelle on January 14, 2011.