|
|
||||||||
Ann Thorac Surg 1999;68:672-677
© 1999 The Society of Thoracic Surgeons
a Department for Cardiovascular Surgery, University Hospital Vaudois, Lausanne, Switzerland
Address reprint requests to Dr von Segesser, Department for Cardiovascular Surgery, University Hospital Vaudois, CHUV, CH-1011 Lausanne, Switzerland
Presented at the Fourth International Conference on Circulatory Support Devices for Severe Cardiac Failure, Houston, TX, Oct 35, 1997.
Abstract
Background. Use of cardiopulmonary bypass for emergency resuscitation is not new. In fact, John Gibbon proposed this concept for the treatment of severe pulmonary embolism in 1937. Significant progress has been made since, and two main concepts for cardiac assist based on cardiopulmonary bypass have emerged: cardiopulmonary support (CPS) and extracorporeal membrane oxygenation (ECMO). The objective of this review is to summarize the state of the art in these two technologies.
Methods. Configuration of CPS is now fairly standard. A mobile cart with relatively large wheels allowing for easy transportation carries a centrifugal pump, a back-up battery with a charger, an oxygen cylinder, and a small heating system. Percutaneous cannulation, pump-driven venous return, rapid availability, and transportability are the main characteristics of a CPS system. Cardio-circulatory arrest is a major predictor of mortality despite the use of CPS. In contrast, CPS appears to be a powerful tool for patients in cardiogenic shock before cardio-circulatory arrest, requiring some type of therapeutic procedures, especially repair of anatomically correctable problems or bridging to other mechanical circulatory support systems such as ventricular assist devices. CPS is in general not suitable for long-term applications because of the small-bore cannulas, resulting in significant pressure gradients and eventually hemolysis.
Results. In contrast, ECMO can be designed for longer-term circulatory support. This requires large-bore cannulas and specifically designed oxygenators. The latter are either plasma leakage resistent (true membranes) or relatively thrombo-resistant (heparin coated). Both technologies require oxygenator changeovers although the main reason for this is different (clotting for the former, plasma leakage for the latter). Likewise, the tubing within a roller pump has to be displaced and centrifugal pump heads have to be replaced over time. ECMO is certainly the first choice for a circulatory support system in the neonatal and pediatric age groups, where the other assist systems are too bulky. ECMO is also indicated for patients improving on CPS. Septic conditions are, in general, considered as contraindications for ECMO.
Conclusions. Ease of availability and moderate cost of cardiopulmonary bypass-based cardiac support technologies have to be balanced against the significant immobilization of human resources, which is required to make them successful.
Use of cardiopulmonary bypass for emergency resuscitation is not new. As early as 1937, John Gibbon proposed this concept for the treatment of severe pulmonary embolism [1, 2]. After the introduction of cardiopulmonary bypass into clinical practice, various pioneers contributed to its application in various emergency situations [3, 4]. An important step for improved applicability of emergency cardiopulmonary bypass was the development of a portable system with significant reduction in complexity and overall size [5]. The reduction from the standard pump console with five pump heads to a small cart with a single pump, battery back-up, an oxygen source, and a small heater was certainly a key step towards simplification. The combination of such portable cardiopulmonary bypass systems with improved percutaneous cannulas [6] in conjunction with active venous drainage allowing for high blood flows with reasonable outer cannula diameter was another important step. Finally, the industrial production of standardized emergency cardiopulmonary support (CPS) systems allowed not only for their widespread application but also for further development, better definition of the indications, and improved outcome [7].
Cardiopulmonary support
Technique
Configuration of cardiopulmonary support systems is now fairly standard. A mobile cart with relatively large wheels allowing for easy transportation in hospital corridors and elevators carries a centrifugal pump, a back-up battery with a charger, an oxygen cylinder, and a small heating system. The disposable set for adults includes a
-inch venous line, quick prime lines, the centrifugal pump head, a low prime oxygenator/heat-exchanger structure, and the arterial line in combination with percutaneous cannulas. Percutaneous arterial cannulas typically measure 17 to 21 F, as compared with percutaneous venous cannulas ranging from 20 to 24 F. Adequate venous return is achieved by transcaval, intraatrial placement of the perforated tip of the percutaneous cannula, which is connected to the inlet of the centrifugal pump, which in turn feeds the blood through the oxygenator heat exchanger structure back to the patient. This setup using relatively small cannulas in combination with pump-driven venous return routinely allows CPS flows between 3 and 4 L/min.
Results
In the series of Reichmann and associates [8], patients with postcardiotomy deterioration, failed coronary angioplasty, trauma, myocardial infarction, pulmonary embolism, and other causes were included for CPS. Sixty-six percent of the patients (24 of 36) successfully cannulated underwent conversion to standard cardiopulmonary bypass for operative procedures or placement of ventricular assist devices. Fifty percent (18 of 36) of patients were successfully weaned and 17% (6 of 36 patients) were long-term survivors.
Hartz and colleagues [9] reported a series of 32 patients resuscitated by cardiopulmonary bypass for cardiac arrest or severe hemodynamic compromise. Overall survival was 22.5%, and only 1 patient (3.4%) of the 29 patients who had cardiac arrest survived and left the hospital.
The multiinstitutional experience reported by Hill and associates [10] summarizes the data of 187 patients from 17 institutions who underwent emergent cardiopulmonary support for cardiac arrest (125 of 187: 67%), cardiogenic shock (44 of 187: 24%), pulmonary insufficiency (9 of 187: 5%), profound hypothermia (7 of 187: 4%), and other causes (2 of 187: 1%). Weaning from bypass was successful in 57 of 187 patients (31%). Sixty-four patients were transferred (34%) to standard bypass or other modes of circulatory assist. Of the total population, 40 patients (21%) were alive greater than 30 days. In survivors, 77% (37 of 48) had major therapeutic interventions as compared with 50% (67 of 135) of nonsurvivors. The major complications related to bypass were technical perfusion problems (cannula) in 3%, poor venous drainage in 3%, bleeding in 1%, and technical perfusion problems (circuit) in 1%.
In contrast, the report of Shawl and colleagues [11] mentions application of CPS in 8 patients with cardiogenic shock from acute myocardial infarction. Seven patients had successful angioplasty and were hospital survivors. At our institution, we have used CPS for coronary angioplasty in 11 high-risk patients with a mean left ventricular ejection fraction of 22 ± 7% [12]. PTCA ± stenting was performed for the left main coronary artery in 5 patients and for other coronary arteries in the remaining 6. Partial cardiopulmonary bypass was initiated [13] with about half of cardiac output and adjusted thereafter to maintain adequate perfusion pressures. Hospital survival was 9 of 11 patients, resulting in a 1-year survival rate of 81%.
Indications
Considering the results given above, it is obvious that cardio-circulatory arrest before initiation of CPS is a major predictor of mortality. In contrast, cardiopulmonary support appears to be a powerful tool for patients in cardiogenic shock before cardio-circulatory arrest requiring some type of therapeutic procedures, especially repair of anatomically correctable problems or bridging to other mechanical circulatory support systems such as ventricular assist devices. Patients requiring coronary artery revascularization by angioplasty or surgery, as well as patients with mechanical complication after acute myocardial infarction (postinfarction ventricular septal defect (VSD), etc), belong to this group [7, 1114]. However, there are numerous other indications for CPS (Table 1). Accidental deep hypothermia is just one example for a correctable nonanatomic pathology with less favorable outcome overall, but more spectacular results in surviving individuals [1517]. Other indications are beating heart donor preservation for transplantation and donor core cooling for improved static organ preservation [18].
|
Another important issue is the reasonable duration of CPS in conjunction with percutaneous cannulas resulting in major pressure gradients. This situation produced, in our hands, major macroscopic hemolysis in some patients after percutaneous perfusion over several hours. Comparative experimental evaluation [19] of percutaneous cannulas (17 F arterial, 21 F venous at 4 L/min) versus large-bore arterial and venous connectors (28 F inner lumen) in our laboratories provided evidence for significantly higher hemolysis after 6 hours (plasma hemoglobin levels: 63.2 ± 03 µmol/L versus 26.3 ± 4.1 µmol/L; p < 0.01). Hence, we believe for long-term support, that there is sufficient evidence to justify conversion from percutaneous CPS to extracorporeal membrane oxygenation (ECMO) with bidirectional perfusion of the target vessels as well as other forms of mechanical circulatory support with large bore connections to the large vessels.
Extracorporeal membrane oxygenation
Extracorporeal membrane oxygenation (ECMO) for circulatory support evolved from the famous ECMO trial, which was primarily initiated for patients with severe respiratory failure [20]. Although patients with chronic heart failure or severely elevated capillary wedge pressure were primarily excluded from this trial, a number of reports on successful use of ECMO in patients with primary cardiac failure appeared in the literature [21, 22]. Ever since, the indications and the techniques used were improved.
ECMO for circulatory support requires, in general, relatively high flows in veno-arterial mode. Hence, compared with percutaneous CPS, larger cannulas requiring either bidirectional cannulation of peripheral vessels or more central cannulation sites are preferred. As ECMO is designed for longer-term use (weeks), the oxygenators used are either of the true membrane type (continuous silicone surface precluding plasma leakage), heparin surface coated [16] allowing for less anticoagulation, or both [23]. Plasma leakage is a major concern during ECMO with traditional hollow-fiber oxygenators built from microporous membranes. The recent development of new membranes made of polyolefin in which the micropores are blind at the blood contacting surface [24] is therefore very interesting.
Likewise, blood pumps with long-term performance are preferred. Many centers use roller pumps and systematically reposition the tubing segment within the pump at regular intervals so that the attrition of the tubing wall due to the rollers is distributed over a long distance. Other groups use centrifugal pumps and replace the pump heads at regular intervals because of the bearing problems that are related to stagnant blood flow and localized thermal buildup. Centrifugal pumps of more recent design using single-point saphire bearing and continuous washing of all rotor and housing surfaces [25] may help top overcome these problems in the future.
Results
The results of ECMO procedures reported to the Extracorporeal Life Support Organisation (ELSO) registry have been published by Bartlett in 1997 [26]. From the almost 14,000 procedures, 10,245 patients survived (10,245 of 13,974: 73%). In the subgroup who underwent ECMO for cardiac failure (1,650/13,974: 12%), the rate of survival was 41%. More recent information about ECMO for cardiac failure can be found in the international summery of July 1997 of the ELSO ECMO registry, which was made available by Bartlett (University of Michigan Medical Center, Ann Arbor, MI: for a total of 16,583 patients on file by July 1997, 12,016 (72%) survived. ECMO for cardiac support was performed in 2,051 patients with 856 survivors (42%). The majority of these patients were pediatric cardiac surgical cases. The primary diagnoses were cardiac surgery in 1,563 patients with 627 survivors (40%), cardiac transplantation in 114 patients with 46 survivors (40%), myocarditis in 57 patients with 29 survivors (51%), myocardiopathy in 95 patients with 49 survivors (52%), and miscellaneous in 222 patients with 105 survivors (47%). The details of the cardiac lesions are given in Table 2. Table 3 summarizes the cardiac criteria for going on ECMO. Cardiac arrest, failure to wean from cardiopulmonary bypass, and cardiac shock were the most frequent reasons. By definition, mode of access for cardiac support was almost exclusively veno-arterial. Table 4 summarizes the complications that were documented during ECMO for cardiac assist. The most frequent mechanical complication was oxygenator failure, which was reported for 6% of the cases. In contrast, all hemorrhagic complications accounted for about 45% of the patients. Considering the fact that embolic complications are also due to a misbalance between anticoagulation and device thromboresistance, it becomes obvious that there is still room for improved perfusion devices and artificial surfaces exposed to the bloodstream. Surface modification is just one approach that has to be mentioned here [23]. This technology has allowed for significant reduction of systemic heparinization during cardiopulmonary bypass over variable time frames [16, 23]. However, we have previously reported that use of protamine in conjunction with heparin surface-coated equipment should be avoided if the antithrombotic activity is to be preserved [27]. Extracorporeal deheparinization by immobilized cationic ligands may be more appropriate under such circumstances [28].
|
|
|
Septic conditions are in general considered as a contraindication for ECMO. Meyer and colleagues analyzed 655 patients of the ELSO registry who underwent ECMO for respiratory support [29]. Sepsis was present in 76 of 655 patients (12%) and absent in 579 of 655 patients (88%). Although survival was lower by univariate analysis in septic children (37% vs 52%: p < 0.02), sepsis was not an independent survival predictor by multivariate analysis (p = 0.12). The authors conclude, based on their series, that this therapy should not be withheld solely because of sepsis.
It should be mentioned here that a significant number of right heart failures before, during, or after cardiac surgical procedures can be substantially improved with inhaled nitric oxide, allowing for reduction of the pulmonary vascular resistance [30]. Likewise, this approach is also useful in conjunction with ECMO [31].
Outlook
Established alternatives to CPS and potential conversion to ECMO for cardiopulmonary resuscitation (CPR) are closed chest massage and intraaortic balloon pumping. However, there are also a number of other concepts under investigation. These include circumferential chest compression by the means of a pneumatic vest, as reported by Halperin and colleagues [32, 33]. Experimental evaluation provided evidence of significantly higher peak aortic pressure, higher coronary perfusion pressure, as well as improved return of spontaneous circulation. In our laboratories, we were also able to document, by the means of an intracoronary flow wire [34], higher intracoronary flow velocity for pneumatically driven vest CPR as compared with manual CPR.
A different approach was selected by Lowe and colleagues [35]. This group has further developed the Anstadt device, which comprises a pneumatic cup with vacuum positioning on the heart for pneumatic direct ventricular actuation. After the development of new synthetic materials and important experimental work, Lowe and colleagues successfully bridged a patient with cardiogenic shock refractory to other treatments to transplantation [35]. One has to admit that effective mechanical ventricular actuation without additional internal or external blood path and their problems is a highly appealing approach.
Finally, one has to mention the overwhelming development of minimally invasive open heart surgery that evolved recently from the CPS technology. Figure 1 gives an intraoperative video-assisted view of the direct closure of an ASD using percutaneous cannulas and pump-driven venous return (the CPS concept) during ventricular fibrillation initiated by an electric fibrillator. The mean pump flows obtained in a consecutive series of 10 patients (mean body weight 67 ± 7 kg; mean surface area 1.7 ± 0.2 m2) undergoing open heart minimally invasive procedures using pump-driven venous return are shown in Figure 2. For the given setup, this technology allowed achievement of a blood flow of just 2.3 L/m2 under normothermic conditions despite loading of the patient with circulating volume, which is somewhat below the target value of 2.4 L/m2. We attribute this finding to the fact that the openings of the percutaneous venous cannulas had to be placed within the caval veins and the latter snared for open right heart surgery. Therefore, pump-driven venous return, which is necessary to achieve adequate flow with small bore cannulas, can easily result in temporary collapse of the veins and consecutive obstruction of the cannula inlet holes. Volume loading can help to maintain a steady flow under such circumstances.
|
|
References
This article has been cited by other articles:
![]() |
L. K. von Segesser, G. Siniscalchi, K. Kang, O. Maunz, J. Horisberger, E. Ferrari, D. Delay, and P. Tozzi Temporary caval stenting improves venous drainage during cardiopulmonary bypass Interactive CardioVascular and Thoracic Surgery, December 1, 2008; 7(6): 1096 - 1100. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. K. von Segesser, E. Ferrari, D. Delay, O. Maunz, J. Horisberger, and P. Tozzi Routine use of self-expanding venous cannulas for cardiopulmonary bypass: benefits and pitfalls in 100 consecutive cases Eur. J. Cardiothorac. Surg., September 1, 2008; 34(3): 635 - 640. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. Lango, M. M. Kowalik, K. Klajbor, and J. Rogowski Circulatory support with right ventricular assist device and intra-aortic balloon counterpulsation in patient with right ventricle failure after pulmonary embolectomy Interactive CardioVascular and Thoracic Surgery, August 1, 2008; 7(4): 643 - 645. [Abstract] [Full Text] [PDF] |
||||
![]() |
S Abdel-Sayed, J Favre, J Horisberger, S Taub, D Hayoz, and L. von Segesser New bench test for venous cannula performance assessment Perfusion, November 1, 2007; 22(6): 411 - 416. [Abstract] [PDF] |
||||
![]() |
L. K. von Segesser Perfusion techniques during surgery of the thoracic and thoraco-abdominal aorta: the veno-arterial bypass MMCTS, June 19, 2007; 2007(0619): 2535. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Foltan, A. Philipp, and D. Birnbaum Extended use of ECC Perfusion, May 1, 2007; 22(3): 173 - 178. [PDF] |
||||
![]() |
S. Rubin, P. E. Falcoz, A. Poncet, and B. Baehrel Traumatic aorto-right atrial fistula and tricuspid valve rupture. Post-operative cardiac and respiratory support with extracorporeal membrane oxygenation Interactive CardioVascular and Thoracic Surgery, December 1, 2006; 5(6): 735 - 737. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. K. von Segesser Peripheral cannulation for cardiopulmonary bypass MMCTS, October 9, 2006; 2006(1009): 1610. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. K. von Segesser, P. Tozzi, E. Riccardo Ferrari, C. Huber, D. Delay, D. Jegger, and J. Horisberger Small access (30F) clinical central venous smart cannulation: is it adequate? Interactive CardioVascular and Thoracic Surgery, October 1, 2006; 5(5): 540 - 543. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. Sung, Y. T. Lee, P. W. Park, K.-H. Park, T.-G. Jun, J.-H. Yang, and Y.-K. Ha Improved Survival After Cardiac Arrest Using Emergent Autopriming Percutaneous Cardiopulmonary Support Ann. Thorac. Surg., August 1, 2006; 82(2): 651 - 656. [Abstract] [Full Text] [PDF] |
||||
![]() |
M L Field, B Al-Alao, N Mediratta, and A Sosnowski Open and closed chest extrathoracic cannulation for cardiopulmonary bypass and extracorporeal life support: methods, indications, and outcomes. Postgrad. Med. J., May 1, 2006; 82(967): 323 - 331. [Abstract] [Full Text] [PDF] |
||||
![]() |
F. Formica, F. Corti, L. Avalli, and G. Paolini ECMO support for the treatment of cardiogenic shock due to left ventricular free wall rupture Interactive CardioVascular and Thoracic Surgery, February 1, 2005; 4(1): 30 - 32. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. K von Segesser, P. Tozzi, I. Mallbiabrrena, D. Jegger, J. Horisberger, and A. Corno Miniaturization in cardiopulmonary bypass Perfusion, July 1, 2003; 18(4): 219 - 224. [Abstract] [PDF] |
||||
![]() |
X. M. Mueller, I. Mallabiabrena, G. Mucciolo, and L. K. von Segesser Optimized venous return with a self-expanding cannula: from computational fluid dynamics to clinical application Interactive CardioVascular and Thoracic Surgery, September 1, 2002; 1(1): 23 - 27. [Abstract] [Full Text] [PDF] |
||||
![]() |
P. Naughton and C. A. Bashour Mechanical Support After Cardiac Surgery Seminars in Cardiothoracic and Vascular Anesthesia, September 1, 2002; 6(3): 237 - 257. [Abstract] [PDF] |
||||
![]() |
M. Kurusz and J. B Zwischenberger Percutaneous cardiopulmonary bypass for cardiac emergencies Perfusion, July 1, 2002; 17(4): 269 - 277. [Abstract] [PDF] |
||||
![]() |
T. Inoue, H. Oka, and H. Oku Percutaneous cardiopulmonary support for the treatment of right ventricular thrombus Perfusion, January 1, 2002; 17(1): 73 - 75. [Abstract] [PDF] |
||||
![]() |
B. Kjaergaard, P. Tolboll, S. Lyduch, and S. Trautner A mobile system for the treatment of accidental hypothermia with extracorporeal circulation Perfusion, December 1, 2001; 16(6): 453 - 459. [Abstract] [PDF] |
||||
![]() |
J. R Pepper Surgery for heart failure: options and outcomes Perfusion, July 1, 2000; 15(4): 287 - 293. [PDF] |
||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| ANN THORAC SURG | ASIAN CARDIOVASC THORAC ANN | EUR J CARDIOTHORAC SURG |
| J THORAC CARDIOVASC SURG | ICVTS | ALL CTSNet JOURNALS |