Special Report

Extracorporeal Life Support Registry Report 2004

STEVEN A. CONRAD,* PETER T. RYCUS,† AND HEIDI DALTON‡

In this article, data from the annual international Extracorpo-real Life Support Organization (ELSO) Registry Reportsthrough July 2004 are presented. Nearly 29,000 patients havereceived extracorporeal life support (ECLS). Of the patients,66% (more than 19,000) were neonatal respiratory failure,with a 77% overall survival to discharge or transfer. Thenumber of neonatal respiratory cases reported to the Registryhas decreased from a peak of 1,500 patients in 1992 and hasleveled off at approximately 800 cases per year. The numberof pediatric respiratory cases has remained at approximately200 cases per year since 1993, with a 56% survival to dis-charge or transfer. Adult respiratory failure continues to bethe smallest age group treated with extracorporeal membraneoxygenation (ECMO), with less than 100 cases per year.Survival to discharge, however, is comparable with pediatricrespiratory failure (53%). Support continues to increasefor cardiac failure across all age groups, with survival todischarge rates of 38%, 43%, and 33% for neonatal, pediat-ric, and adults, respectively. Survival in pediatric and adultrespiratory failure cases supported with ECLS has remainedfairly consistent over the past 5 years. ASAIO Journal 2005;51:4–10.

The Extracorporeal Life Support Organization (ELSO) wasformed in 1989, as a group of centers who were actively usingextracorporeal life support (ECLS) in the management of car-diopulmonary failure. Among the functions of ELSO are en-hancing communication, developing guidelines for ECLS, andmaintaining a registry of ECLS cases. This year, ELSO cele-brates its 15th anniversary, with more than 100 participatingdomestic and international centers who actively report data tothe registry.

Maintaining a registry of ECLS cases is one of the majorfunctions of ELSO. Originally, the ELSO Registry was imple-mented as four databases structured as flat files, correspondingto neonatal, pediatric, cardiac, and adult categories. Mostfields were recorded as free text entries, making queries diffi-cult and inconsistent. With the growth of the Registry, thelimitations of this format were recognized, and the databasewas reengineered as a single relational database with the use

of coded entries from standardized classification systems suchas International Classification of Diseases (ICD-9) and CurrentProcedural Terminology (CPT). The database, including dataentry forms and reports, was first implemented in MicrosoftAccess (Microsoft Corporation, Redmond, WA). An electronicdata entry mechanism was created to replace paper formsusing Microsoft Word forms submitted by electronic mail thatcould be imported directly into the database. With continuedgrowth, the database content was migrated to Microsoft SQLServer, and a web based data entry system was created. Acardiac addendum was implemented to supplement the stan-dard Case Report Form for cardiac support cases to capturecase details not adequately handled by the existing codingsystems.

Methods

The ECLS Registry is among the most important functions ofELSO. Data reported to ELSO include basic patient descriptiveinformation, perinatal information (for neonates), preECLSphysiologic data, ECLS equipment and implementation data,complications (mechanical and patient), and outcome infor-mation. To obtain more specific data on cardiac failure pa-tients, an addendum to track more specific information wascreated in 2001.

All cases submitted to the Registry through June 2004 areincluded in this analysis. The Registry captures the vast major-ity of all ECLS cases performed in the United States becausemost active centers in the United States report their cases. Italso captures cases from a number of international centers andthus represents a broad cross-section of ECLS cases.

The Registry categorizes cases as neonatal, pediatric, andadult. Neonatal cases are those aged 30 days or younger at thetime of initiation of ECLS. Pediatric cases include those over 30days and younger than 18 years, and adults are those 18 yearsof age and above.

Support categories are recorded as pulmonary, cardiac, orextracorporeal cardiopulmonary resuscitation (ECPR). Pulmo-nary cases are defined as those in which the primary indicationfor support is hypoxemic or hypercapnic acute respiratoryfailure, even if some degree of concomitant cardiac dysfunc-tion exists. Cardiac cases, likewise, include those where theprimary reason for support is cardiac dysfunction. This cate-gory includes patients with primary cardiomyopathies, post-operative cardiac surgical cases (congenital and noncongeni-tal), and similar etiologies including bridge to transplant.Respiratory failure is frequently coexistent. ECPR captures sit-uations of rapid deployment support in cases of established orimpending cardiopulmonary arrest.1 Criteria for initiation ofECLS vary slightly from center to center but follow published

From the *Louisiana State University Health Sciences Center,Shreveport, Louisiana; the †Extracorporeal Life Support Organization,Ann Arbor, Michigan; and the ‡Children’s National Medical Center,Washington, DC.

Submitted for consideration October 2004; accepted for publicationin revised form November 2004.

Reprint Requests: Dr. Steven A. Conrad, LSU Health Sciences Center,1501 Kings Highway, P.O. Box 33932, Shreveport, LA 71130-3932.

DOI: 10.1097/01.MAT.0000151922.67540.E9

ASAIO Journal 2005

4

selection guidelines.2 All patients have acute, potentially re-versible cardiopulmonary failure in which conventional sup-port has been inadequate. Conventional support includes pres-sure limited ventilation, high frequency ventilation, inhalednitric oxide, surfactant administration, prone positioning, fluidmanagement, and optimization of circulatory function withpharmacologic support as appropriate for age and type oforgan dysfunction.

The modes of support defined in the Registry are variationsof either venoarterial (partial to total cardiopulmonary bypass)or venovenous (prepulmonary oxygenation). Recently, a hy-brid mode has been described that combines venoarterial andvenovenous support. The support modes are described in Ta-ble 1.

Complications related to or attributed to ECLS are defined asmechanical (those that involve the ECLS circuit components,including cannulae) or patient related. In general, a complica-tion is recorded if it requires active management such asequipment change, a change in therapy, or results in organdysfunction. The complications recorded are predefined byELSO and are standardized across centers.

Data were extracted from the Registry using StructuredQuery Language (SQL) queries. Statistical procedures usedincluded descriptive statistics and data categorization. Presen-tation graphs were created with S-Plus (Insightful Corporation,Seattle, WA).

Results

All cases entered into the Registry as of June 20, 2004, andprovided in the July 2004 ELSO International Summary arelisted by age and support category in Table 2. The majority(66%) of patients are neonatal, with an overall survival of 77%.Both the number of annual cases and overall survival rates inneonatal ECMO have shown a decline over recent years.These changes likely reflect the availability of other alternativetherapies for neonatal respiratory failure support such as highfrequency ventilation, inhaled nitric oxide, and surfactant ad-ministration. Patients responding to these less invasive thera-pies do not require ECMO. Those neonatal ECMO patientswho fail multiple therapies before ECMO support may be“sicker” than those treated in the past, and this may influenceoverall outcome. Although this seems a logical explanation,this premise has not been confirmed. Pediatric, cardiac, andadult cases have shown a marginal increase in the proportionof patients treated (Figure 1). Overall survival in pediatric,cardiac, and adult categories did not change substantially from1995 to 1998.3,4 Compared with 19945 data, however, animproved survival is noted in adults (47% vs. 36%), and slightimprovement is noted in pediatric patients (53% vs. 50%).

Neonatal

The number of neonatal respiratory support cases (up to 30days of age) reported showed a decreasing trend that existedfrom 1992–1998 and then has remained steady at approxi-mately 800 cases per year (Figure 2). The probable reasons forthis are several and include improved results with overallperinatal and neonatal care and the use of nitric oxide, surfac-tant, and high frequency oscillation.6 Data on survival withthese therapies are not reported to the Registry, and thusoverall outcome between these patients and those who receiveECMO is not available. Note that the 2004 Figure is underrep-resentative because of delays in reporting when assessing long-term follow up.

The proportion of cases with congenital diaphragmatic her-

Table 2. Total Numbers of ECLS Cases Reported by the ELSORegistry International Summary, July 2004

Total Cases

Survive to Dischargeor Transfer

Number %

NeonatalRespiratory 19,061 14,681 77Cardiac 2,215 841 38ECPR 151 65 43

PediatricRespiratory 2,762 1,536 56Cardiac 2,936 1,256 43ECPR 282 111 39

AdultRespiratory 972 515 53Cardiac 474 156 33ECPR 132 50 38

Total 28,985 19,211 66

ECLS, extracorporeal life support.

Table 3. Extracorporeal Life Support for Neonatal RespiratoryFailure (July 2004)

TotalCases

No.Surviving

%Surviving

Neonatal cases by diagnosisCDH 4,491 2,367 53MAS 6,560 6,160 94PPHN/PFC 2,914 2,287 78Infant RDS 1,380 1,161 84Sepsis 2,384 1,794 75Other 1,567 1,003 64

Neonatal mode of ECLSVA 13,301 9,882 74VV 276 220 80VVDL 3,537 3,053 86VA(�V) 1,159 868 75VV 3 VA 544 360 66VVDL�V 410 346 84

CDH, congenital diaphragmatic hernia; MAS, meconium aspira-tion syndrome; PPHN/PFC, persistent fetal circulation; RDS, respi-ratory distress syndrome; VA, venoarterial; VV, venovenous; VVDL,venovenous double lumen; ECLS, extracorporeal life support.

Table 1. Definitions of Support Modes Used in the ELSORegistry

Description

VA VenoarterialVA�V Venoarterial with retrograde venous drainageV V Venovenous, two or more cannulaeV VDL Venovenous, single double lumen cannulaV VDL�V V VDL with retrograde venous drainageV V-�VA Initial VV with conversion to VAV VA Hybrid venovenous and venoarterial support

5ELSO REGISTRY REPORT 2004

Figure 2. Neonatal respiratoryECLS cases reported to the ELSORegistry as of July 2004. The bargraph represents the number ofcases reported on an annual ba-sis, whereas the line graph repre-sents the cumulative cases re-ported as of the end of each year.A steady decrease in the numberof cases reported annually hasbeen occurring since 1992. TheFigure for 2004 is lower than ex-pected because of delays in thereporting of cases. ECLS, extra-corporeal life support.

Figure 3. Neonatal respiratoryECLS cases reported to the ELSORegistry as of July 2004. The bargraph represents the percentageof cases by diagnosis reported onan annual basis. ECLS, extracor-poreal life support; RDS, respira-tory distress syndrome; PPHN/PFC, persistent fetal circulation;MAS, meconium aspiration syn-drome; CDH, congenital dia-phragmatic hernia.

Figure 1. ECLS cases reportedto the ELSO Registry as of July2004. The bar graph representsthe number of cases reported onan annual basis, whereas the linegraph represents the cumulativecases reported as of the end ofeach year. A steady decrease inthe number of cases reported an-nually has been occurring since1992. ECLS, extracorporeal lifesupport.

6 CONRAD, RYCUS, AND DALTON

nia (CDH) has been increasing, whereas the proportion withrespiratory distress syndrome, meconium aspiration syndrome(MAS), and sepsis has been decreasing (Figure 3).

The diagnoses and modes of support are summarized inTable 3. The most common mode of support in neonatalrespiratory failure remains venoarterial (VA), but the numbermanaged with venovenous access using a double lumen cath-eter (VVDL) remains significant at more than 20% of cases. Thesurvival rate with the VVDL catheter is higher than that re-ported with VA support, but whether this reflects a differencein severity of illness between patients or is a result of the modeof support is unknown.

Pediatric

The number of pediatric patients (from 30 days up to 18years of age) supported for respiratory failure on an annualbasis since inception of the Registry is given in Figure 4. Thenumber of annual cases reported continued to rise until 1994,when cases leveled off at approximately 200 patients per year

(Figure 4). Survival remains relatively stable at greater than50%. Diagnosis does not appear to have a major impact uponsurvival in this group (Table 4). The most common mode ofsupport remains venoarterial, but venovenous is becomingmore frequent, accounting for approximately one third of pe-diatric respiratory cases in the past year. Perhaps the mostintriguing factor regarding pediatric ECMO is the expansion topatient groups who would have been excluded from ECMOsupport in years past. Today, successful treatment with ECMOhas been described in patients with trauma, immunosuppres-sion, and underlying bleeding disorders (hemophilia), as wellas in patients with established multiple organ systems failure.

Adult

The application of ECLS to adult respiratory failure rapidlygrew until 1996 and has remained fairly consistent at approx-imately 100 cases per year (Figure 5). Adults remain poten-tially the most underserved group in terms of ECMO support.Overall survival is remaining relatively stable at approximately50% but is quite variable and dependent upon the diagnosis(Table 5). The best outcomes appear to be with viral pneumo-nia, aspiration pneumonia, and non-ARDS respiratory failure.The lingering effects of several adult trials of ECMO, whichshowed no benefit from ECMO, have left many clinicians withlittle interest in pursuing ECMO support for patients failing con-

Figure 4. Pediatric respiratoryECLS cases reported to the ELSORegistry as of July 2004. The bargraph represents the number ofcases reported on an annual ba-sis, whereas the line graph repre-sents the cumulative cases re-ported as of the end of each year.The number of annual cases re-ported continues to grow but maybe reaching a plateau. The Figurefor 2004 is lower than expectedbecause of delays in the reportingof cases. ECLS, extracorporeallife support.

Table 4. Extracorporeal Life Support for Pediatric RespiratoryFailure (July 2004)

TotalCases

No.Surviving

%Surviving

Pediatric cases by diagnosisBacterial pneumonia 290 157 54Viral pneumonia 728 457 63Aspiration pneumonia 168 110 65ARDS 348 188 54ARF, non-ARDS 605 286 47Other 671 359 54

Pediatric mode of ECLSVA 1,663 851 51VV 510 328 64VVDL 283 200 71VA(�V) 89 42 47VV 3 VA 163 74 45VVDL�V 44 32 73

ARF, acute respiratory failure; ARDS, acute respiratory distresssyndrome; ECLS, extracorporeal life support; VA, venoarterial; VV,venovenous; VVDL, venovenous double lumen.

Table 5. Extracorporeal Life Support for Adult RespiratoryFailure (July 2004)

TotalCases

No.Surviving

%Surviving

Adult cases by diagnosisBacterial pneumonia 186 97 52Viral pneumonia 87 54 62Aspiration pneumonia 32 18 56ARDS, postop/trauma 132 68 52ARDS, not postop/trauma 196 100 51ARF, non-ARDS 55 35 64Other 317 154 49

ARDS, acute respiratory distress syndrome; ARF, acute respira-tory failure.

7ELSO REGISTRY REPORT 2004

ventional care. A current era trial of ECMO in adult patients isunderway in the United Kingdom, with results expected withinthe next year. The lack of available adult ECMO centers is anotherfactor in the lack of adult ECMO representation. A newly fundedNIH grant to develop and implement large, double lumen, singlecannulae for adult ECMO support may provide an easier route forcannulation in adult patients. Whether these events will lead toan increase in the use of ECMO in the adult patient is unknownat this time. Expansion of many previously exclusively neonatal orpediatric ECMO programs to the adult patient is underway insome ECMO centers.

Cardiac

Cardiac support cases are summarized in Figures 6–9. Thenumber of cases reported annually has been increasing, asECMO support remains the primary modality for infants andsmall pediatric patients with intractable cardiac failure. Thefigure for 2004 underrepresents the number of cases performedbecause of delays in reporting. Overall survival for neonatalcardiac cases has been declining slightly, likely as a result ofECMO being applied to more and more complex cardiacdiseases such as hypoplastic left heart patients. The vast ma-jority of patients are treated after repair of congenital heartdisease (Table 6). The majority of cardiac cases are neonatal(0–30 days), followed by older age groups. As in previousyears, venoarterial support was used for almost all of the casesreported. As research into alternative cardiac support devicesfor neonates and pediatric patients continues, ECMO may seea further decline in support, but it remains the main modalityfor infants and children with cardiac disease at this time.

Complications

As pointed out by Bartlett,3 a valuable role of the Registry isto permit benchmarking of individual centers’ performance.ELSO distributes to each center the experience of that center inconjunction with the total Registry experience for comparison.The Registry provides information not only on data such asoutcome but also on complications, including those for respi-

ratory support (Table 7) and cardiac support (Table 8). Thetables report the incidence of the complications in percentageof total for that group and the survival in percentage in patientsexperiencing those complications. The complication list is asubset of all of the complications reported, which here areorganized into mechanical complications related to the sup-port circuit, and to patient complications. Hemorrhage (gas-

Table 6. Extracorporeal Life Support for Cardiac Failure(July 2004)

Total Runs No. Survived % Survived

0–30 daysCongenital Defect 2,006 719 36

Cardiac Arrest 24 5 21Cardiogenic

Shock22 11 50

Cardiomyopathy 72 48 67Myocarditis 27 11 41Other 168 74 44

31 days and �1 yearCongenital Defect 1,318 548 42

Cardiac Arrest 25 6 24Cardiogenic

Shock11 4 36

Cardiomyopathy 61 28 46Myocarditis 33 18 55Other 155 65 42

1 year and �16 yearsCongenital Defect 740 297 40

Cardiac Arrest 49 19 39Cardiogenic

Shock34 11 32

Cardiomyopathy 200 108 54Myocarditis 96 60 63Other 260 113 43

�16 yearsCongenital Defect 42 12 29

Cardiac Arrest 43 9 21Cardiogenic

Shock74 34 46

Cardiomyopathy 73 25 34Myocarditis 14 9 64Other 297 92 31

Figure 5. Adult respiratoryECLS cases reported to the ELSORegistry as of July 2004. The bargraph represents the number ofcases reported on an annual ba-sis, whereas the line graph repre-sents the cumulative cases re-ported as of the end of each year.The number of annual cases re-ported grew rapidly until 1996and might have leveled off. TheFigure for 2004 is lower than ex-pected because of delays in thereporting of cases. ECLS, extra-corporeal life support.

8 CONRAD, RYCUS, AND DALTON

Figure 6. Cardiac supportECLS cases reported to the ELSORegistry as of July 2004 in theneonatal age group. The bargraph represents the number ofcases reported on an annual ba-sis, whereas the line graph repre-sents the cumulative cases re-ported as of the end of each year.The number of annual cases re-ported continues to grow but maybe approaching a plateau. TheFigure for 2004 is lower than ex-pected because of delays in thereporting of cases. ECLS, extra-corporeal life support.

Figure 7. Cardiac supportECLS cases reported to the ELSORegistry as of July 2004 in thepediatric group younger than 1year. The bar graph representsthe number of cases reported onan annual basis, whereas the linegraph represents the cumulativecases reported as of the end ofeach year. The number of annualcases reported continues to growbut may be approaching a pla-teau. The Figure for 2004 is lowerthan expected because of delaysin the reporting of cases. ECLS,extracorporeal life support.

Figure 8. Cardiac supportECLS cases reported to the ELSORegistry as of July 2004 in thepediatric age group up to age 16.The bar graph represents thenumber of cases reported on anannual basis, whereas the linegraph represents the cumulativecases reported as of the end ofeach year. The number of annualcases reported continues to growbut may be approaching a pla-teau. The Figure for 2004 is lowerthan expected because of delaysin the reporting of cases. ECLS,extracorporeal life support.

9ELSO REGISTRY REPORT 2004

trointestinal, cannula site, and surgical site) remains an atten-dant problem and appears to be associated with a pooreroutcome. Neurologic complications are less frequent but arealso associated with poorer outcome.

Discussion

The application of ECLS in the neonatal population is de-creasing, presumably because of improvements and innova-tions in management of neonatal respiratory failure. In con-trast, the application in pediatric and adult respiratory failurerose significantly and now has steadied off, whereas the num-ber of cardiac applications appears to be stabilizing. Survivalin each of the categories has not significantly changed over thepast 2 years.

The ELSO Registry is a comprehensive database of extracor-poreal support data in the neonatal, pediatric, and adult pop-ulations and remains a comprehensive and valuable resourceto the ECLS community. With the reengineering currently un-derway, the Registry will have the capability of more rapid and

error free data entry via electronic submission, access fromdomestic and international centers via the Internet for timelyreporting of data, and automation in verification of data.

References

1. Younger JG, Schreiner RJ, Swaniker F, Hirschl RB, Chapman RA,Bartlett RH: Extracorporeal resuscitation of cardiac arrest. AcadEmerg Med 6: 700–707, 1999.

2. Zwischenberger JB, Steinhorn RH, Bartlett RH: ECMO: Extracorpo-real Cardiopulmonary Support in Critical Care, 2nd ed. AnnArbor, MI: Extracorporeal Life Support Organization; 2001.

3. Bartlett RH: Extracorporeal Life Support Registry Report 1995.ASAIO J 43: 104–107, 1997.

4. Conrad SA, Rycus PT: Extracorporeal life support 1997. ASAIO J 44:848–852, 1998.

5. Tracy TF Jr, DeLosh T, Bartlett RH: Extracorporeal Life SupportOrganization 1994. ASAIO J 40: 1017–1019, 1994.

6. Roy BJ, Rycus P, Conrad SA, Clark RH: The changing demographicsof neonatal extracorporeal membrane oxygenation patients re-ported to the Extracorporeal Life Support Organization (ELSO)Registry. Pediatrics 106: 1334–1338, 2000.

Table 8. Mechanical and Patient Related Complications forthe Cardiac Population

0–30days

31 daysand

�1 year

1 yearand

�16 years�16years

MechanicalOxygenator failure 7.2 (23) 7.2 (28) 9.1 (37) 16.4 (27)Tubing rupture 0.7 (31) 1.1 (24) 2.0 (30) 0.9 (20)Pump malfunction 1.3 (32) 1.9 (26) 2.2 (42) 1.8 (36)Cannula problems 6.7 (33) 5.9 (35) 6.4 (31) 6.8 (32)

Patient relatedGI hemorrhage 0.9 (5) 1.8 (14) 2.8 (23) 2.4 (15)Cannula site bleeding 6.8 (27) 6.7 (23) 10.7 (44) 12.9 (30)Surgical site bleeding 31.0 (29) 33.9 (36) 31.3 (42) 31.9 (27)Hemolysis 10.8 (24) 9.9 (33) 8.5 (35) 8.1 (34)Brain death 1.3 (0) 5.1 (0) 9.5 (0) 7.9 (0)Seizures: clinicallydetermined

9.7 (29) 11.0 (24) 6.8 (21) 4.8 (12)

GI, gastrointestinal.

Figure 9. Cardiac supportECLS cases reported to the ELSORegistry as of July 2004 in the agegroup 16 years and older. The bargraph represents the number ofcases reported on an annual ba-sis, whereas the line graph repre-sents the cumulative cases re-ported as of the end of each year.The number of annual cases re-ported continues to grow but maybe approaching a plateau. TheFigure for 2004 is lower than ex-pected because of delays in thereporting of cases. ECLS, extra-corporeal life support.

Table 7. Mechanical and Patient Related Complications forRespiratory Population

Neonatal Pediatric Adult

MechanicalOxygenator failure 5.7 (55) 13.8 (44) 18.2 (43)Tubing rupture 0.7 (74) 3.8 (47) 4.0 (30)Pump malfunction 1.8 (68) 3.1 (47) 4.1 (37)Cannula problems 11.1 (70) 14.2 (48) 10.7 (42)

Patient relatedGI hemorrhage 1.7 (46) 4.0 (25) 4.3 (26)Cannula site bleeding 6.1 (68) 9.2 (60) 11.5 (47)Surgical site bleeding 6.1 (46) 16.0 (47) 22.4 (35)Hemolysis 12.2 (68) 8.8 (42) 5.3 (28)Brain death 1.0 (0) 6.0 (0) 3.8 (0)Seizures: clinically

determined10.9 (62) 7.3 (35) 2.0 (45)

Table entries are in percentage reported (% survival). GI, gastro-intestinal.

10 CONRAD, RYCUS, AND DALTON