Techniques inextracorporealcirculationFOURTH EDITION Edited by PHILIP H KAY MA DM FRCS Consultant Cardiothoracic Surgeon, Yorkshire Heart Centre, The General Inﬁrmary, Leeds, UK and CHRISTOPHER M MUNSCH ChM FRCS (C/Th) Consultant Cardiothoracic Surgeon, Yorkshire Heart Centre, The General Inﬁrmary, Leeds, UK A member of the Hodder Headline Group LONDON
Contents Contributors vii Foreword xi Preface to Fourth Edition – 50 years on xiii Preface to Third Edition xiv Preface to Second Edition xv Preface to First Edition xvi Acknowledgements xvii1 A brief history of bypass 1 Anil Kumar Mulpur and Christopher M Munsch2 Design and principles of the extracorporeal circuit 7 Medtronic, Inc., A Manufacturer of Technologies for Extracorporeal Circulation3 Physiology and pathophysiology of extracorporeal circulation 23 Jonathan AJ Hyde and Ralph E Delius4 Anaesthesia for cardiopulmonary bypass 57 Linda Nel and John WW Gothard5 Monitoring and safety in cardiopulmonary bypass 76 Jonathan M Johnson, Stephen Robins and Jonathan A J Hyde6 Priming ﬂuids for cardiopulmonary bypass 99 Piet W Boonstra and Y John Gu7 Filters in cardiopulmonary bypass 108 Farah NK Bhatti and Timothy L Hooper8 The inﬂammatory response to cardiopulmonary bypass 117 Saeed Ashraf9 Pulsatile cardiopulmonary bypass 133 Terry Gourlay and Kenneth M Taylor10 Cardiopulmonary bypass and the brain 148 G Burkhard Mackensen, Hilary P Grocott and Mark F Newman
vi Contents11 Cardiopulmonary bypass in children with congenital heart disease 177 Carin van Doorn and Martin Elliott12 Intraoperative myocardial protection 184 John WC Entwistle III and Andrew S Wechsler13 Blood conservation 210 Mike Cross14 Mechanical circulatory support 236 Stephen Westaby and Satoshi Saito15 Extracorporeal membrane oxygenation 254 Scott K Alpard, Dai H Chung and Joseph B Zwischenberger16 The extended use of the extracorporeal circuit 292 Philip H Kay, Anil Kumar Mulpur, Dumbor Ngaage, Samir Shah, Kieran Horgan, John Pollitt and Stephen D Hansbro17 Cardiopulmonary bypass during Port-access™ and robotic surgery 298 Alan P Kypson and W Randolph Chitwood Jr18 Cardiac surgery without cardiopulmonary bypass 315 Joseph P McGoldrick19A The development of clinical perfusion education and standards in the UK and Ireland 332 Michael Whitehorne19B Standards, guidelines and education in clinical perfusion: the European perspective 337 Ludwig K Von Segesser19C Perfusion education in the USA at the turn of the twentieth century 341 Alfred H Stammers Index 345
ContributorsScott K Alpard MD Mike CrossSurgical Research Fellow, Consultant Anaesthetist,Division of Cardiothoracic Surgery, Yorkshire Heart Centre,University of Texas Medical Branch, The General Inﬁrmary at Leeds,Galveston, TX, USA Leeds, UKSaeed Ashraf FRCS(CTh) MD Ralph E Delius MDConsultant Cardiothoracic Surgeon, Children’s Hospital of Michigan,Regional Cardiothoracic Centre, Detroit, MI, USThe Morriston Hospital, and Honorary Senior Lecturer,University of Swansea, Carin van DoornSwansea, UK Senior Lecturer in Cardiothoracic Surgery,Farah NK Bhatti University College London,Specialist Registrar in Cardiothoracic Surgery, and Honorary Consultant Cardiothoracic Surgeon,Wythenshawe Hospital, Cardiothoracic Unit,Manchester, UK Great Ormond Street Hospital for Children, London, UKPiet W BoonstraDepartment of Cardiothoracic Surgery, Martin ElliottUniversity Hospital, Consultant Cardiothoracic Surgeon,Groningen, The Netherlands Cardiothoracic Unit, Great Ormond Street Hospital for Children,Walt Carpenter London, UKDirector of Cardiopulmonary R&D,Medtronic Perfusion Systems, John WC Entwistle III MD PhDMinneapolis, MN, USA Assistant Professor of Cardiothoracic Surgery, Department of Cardiothoracic Surgery,W Randolph Chitwood Jr MD Drexel University College of Medicine,Senior Associate Vice Chancellor and Director, Philadelphia, PA, USANorth Carolina Cardiovascular Institute,Professor and Chairman,Professor of Surgery, John WW Gothard FRCAChief, Division of Cardiothoracic and Vascular Surgery, Consultant Anaesthetist,The Brody School of Medicine, Royal Brompton Hospital,East Carolina University, London, UKGreenville, NC, USA Terry Gourlay PhD BSc (Hons) CBiol MIBiol ILTHE FRSHDai H Chung MD British Heart Foundation Perfusion Specialist,Assistant Professor of Surgery, Department of Cardiothoracic Surgery,Chief, Section of Pediatric Surgery, NHLI,Department of Surgery, Imperial College Medical School,University of Texas Medical Branch, Hammersmith Hospital Campus,Galveston, TX, USA London, UK
viii ContributorsHilary P Grocott MD FRCPC G Burkhard Mackensen MDAssociate Professor, Assistant Professor,Department of Anesthesiology, Klinik für Anaesthesiologie,Duke Heart Center, Technische Universität München,Duke University Medical Center, Klinikum rechts der Isar,Durham, NC, USA München, Germany Joseph P McGoldrick MD FRCSY John Gu Consultant Cardiothoracic Surgeon,Department of Cardiothoracic Surgery, The Yorkshire Heart Centre,University Hospital, The General Inﬁrmary at Leeds,Groningen, The Netherlands Leeds, UKStephen D Hansbro Anil Kumar Mulpur MS MCh FRCS (Edin)Department of Clinical Perfusion, FRCS (Glasgow) FRCS C/Th (Edin) FETCSLeeds General Inﬁrmary, Consultant Cardiothoracic Surgeon,Leeds, UK Sri Sathya Sai Institute of Higher Medical Sciences, Whiteﬁeld, Bangalore, IndiaTimothy L Hooper Christopher M Munsch ChM FRCS (C/Th)Consultant Cardiac Surgeon, Consultant Cardiothoracic Surgeon,Wythenshawe Hospital, Department of Cardiothoracic Surgery,Manchester, UK The Yorkshire Heart Centre, The General Inﬁrmary,Kieran Horgan Leeds, UKDepartment of General Surgery,Leeds General Inﬁrmary, Linda Nel FRCALeeds, UK Consultant Anaesthetist, Southampton University Hospitals Trust,Jonathan AJ Hyde MD FRCS(CTh) Southampton, UKConsultant Cardiac Surgeon, Mark F Newman MDRoyal Sussex County Hospital, Professor and Chairman,Brighton, UK Department of Anesthesiology, Duke Heart Center,Jonathan M Johnson BSc ACP Duke University Medical Center,Chief Clinical Perfusionist, Durham, NC, USARoyal Sussex County Hospital,Brighton, UK Dumbor Ngaage Department of Cardiothoracic Surgery, Leeds General Inﬁrmary,Bruce Jones Leeds, UKCardiopulmonary Product Manager,Medtronic Perfusion Systems, John PollittMinneapolis, MN, USA Department of General Surgery, Leeds General Inﬁrmary,Philip H Kay MA DM FRCS Leeds, UKConsultant Cardiothoracic Surgeon, Stephen Robins PgDip AACPThe Yorkshire Heart Centre, Chief Clinical Perfusionist,The General Inﬁrmary, New Cross Hospital,Leeds, UK Wolverhampton, UKAlan P Kypson MD Satoshi Saito MD PhDAssistant Professor of Surgery, Senior Clinical Research Fellow,Division of Cardiothoracic Surgery, Department of Cardiothoracic Surgery,Brody School of Medicine, Oxford Heart Centre,East Carolina University, John Radcliffe Hospital,Greenville, NC, USA Oxford, UK
Contributors ixLudwig K Von Segesser Andrew S Wechsler MDService de Chirurgie Cardio-Vasculaire, Professor and Chairman,Centre Hospitalier Universitaire Vaudois (CHUV), Department of Cardiothoracic Surgery,Lausanne, Switzerland Drexel University College of Medicine, Philadelphia, PA, USASamir ShahDepartment of Cardiothoracic Surgery, Stuart WellandLeeds General Inﬁrmary, European Marketing Manager,Leeds, UK Medtronic Europe Sàrl, Tolochenaz, SwitzerlandAlfred H Stammers MSA CCPChief Perfusionist, Stephen Westaby PhD FETCS MSDepartment of Surgery, Consultant Cardiac Surgeon,Geisinger Medical Center, Department of Cardiothoracic Surgery,Danville, PA, USA Oxford Heart Centre, John Radcliffe Hospital,Editor, Journal of Extracorporeal Technology Oxford, UKJeanne Stanislawski Michael Whitehorne MSC ACP FCCPSCardiopulmonary Product Manager, Consultant Clinical Perfusion Scientist,Medtronic Perfusion Systems, Department of Cardiothoracic Surgery,Minneapolis, MN, USA King’s College Hospital,Wendy Svee London, UKCardiopulmonary Product Manager, Joseph B Zwischenberger MDMedtronic Perfusion Systems, Professor of Surgery, Medicine, and Radiology,Minneapolis, MN, USA Director, General Thoracic Surgery and ECMO Programs,Kenneth M Taylor Division of Cardiothoracic Surgery,Professor of Cardiac Surgery, University of Texas Medical Branch,Department of Cardiothoracic Surgery, Galveston, TX, USANHLI,Imperial College Medical School,Hammersmith Hospital Campus,London, UK
ForewordI am most grateful to the editors for their invitation to preference for medical revascularisation (percutaneouswrite the foreword for this – the fourth edition of transluminal coronary angioplasty, stents, the expandingTechniques of Extracorporeal Circulation. My ofﬁce book- range of percutaneous coronary interventions) at thecase currently contains the three previous editions, and expense of what we used to consider the unassailableif I am not considered presumptuous, I look forward to gold standard: conventional coronary artery bypass graftadding a copy of this fourth edition. surgery. John Gibbon received international acclaim for his For cardiopulmonary bypass and the perfusion pro-courage and determination on the 50th anniversary of fessionals, the challenge was different, but no less daunt-that historic open-heart operation in Philadelphia on ing: would off-pump coronary bypass render the use ofMay 5th 1953 when the heart–lung machine was used cardiopulmonary bypass in coronary surgery obsolete?successfully in a patient for the ﬁrst time. Fifty years does One might reasonably assume that now is not the time tonot seem to me to be that long, although when I was invest in cardiopulmonary bypass – far too risky! I begyounger (i.e. not over 50) my opinions were different. It to differ, however. I would suggest that now is preciselyis always fascinating to hear graphic personal accounts of the time for investment in cardiopulmonary bypass.those early days of cardiopulmonary bypass where the It should, however, be speciﬁcally targeted investment,challenges seemed almost insuperable. a balanced investment portfolio. Things are very different 50 years on. The technology First, the further continual reﬁnement of cardio-and the practice of cardiopulmonary bypass have been pulmonary bypass remains as great a challenge and anreﬁned to an exceptional degree. The beneﬁts to the car- opportunity now as it was in the 1950s. Developments indiac surgical patients and the cardiac team of surgeons, medicine in general (particularly including molecularanaesthetists, perfusionists and nursing staff have been science and genetics/genomics) offer great potential toincalculable. I was asked a few years ago to give a talk on increase our understanding of the fundamental patho-the topic: ‘Can cardiopulmonary bypass become more physiological mechanisms of cardiopulmonary bypasspatient friendly?’ I observed at the start of the talk that and consequently introduce more effective preventativecardiopulmonary bypass had been a great friend to cardiac and therapeutic strategies.surgical patients and to cardiac surgeons and their col- Second, we need to broaden our horizons as far asleagues, and that John Gibbon would be turning over in extracorporeal circulation is concerned. Its potential roleshis grave at the very thought of the topic I had been given. in other forms of surgery (both in cardiac and non- I was exaggerating of course, and Gibbon and his fellow cardiac) in local circulations and in systemic circulatorypioneers would be the very last to encourage complacency and respiratory support present a wealth of opportunities.regarding cardiopulmonary bypass. As it so happened, the Third and ﬁnally, to quote the UK Prime Minister Tonyfollowing year I was asked to speak to another question: ‘Is Blair (who interestingly was born on May 5th 1953 –cardiopulmonary bypass in 2001 as good as it gets?’ I trust Gibbon’s historic day) ‘... education, education, education’.you will already have worked out that I was somewhat We need to apply ourselves, both individually and in thenegative in my response to that proposition! medical and perfusion schools of the future. New science They say that things come along in threes – and it fell brings with it new terminologies – we need to learn theto me to address another cardiopulmonary bypass languages. Then we can communicate with the basic sci-related question in 2002. ‘Would you invest in cardiopul- entists, with molecular experts, with geneticists and whomonary bypass in 2002?’ was the title. I found this exer- knows who else!cise particularly interesting. By then, cardiac surgery and It may be a daunting prospect for us, but spare acardiopulmonary bypass were each facing major chal- thought also for the basic scientists – when have they everlenges to their future importance. For cardiac surgery, before been visited by an enthusiastic perfusionist orthe challenge – indeed the threat – was the increasing cardiac surgical trainee?
xii Foreword So these are the challenges, and the opportunities. honourable tradition of risk-takers. As one of the NorthThis textbook will help considerably. Philip Kay and American insurance corporations proclaims in its adver-Chris Munsch have brought into this book the right tising: ‘the only risk is not to take one’.subjects and the right authors. This book contains a lot of John Gibbon would profoundly agree with that.information, which can be a launch pad for new ideasand new questions. Professor Kenneth M Taylor MD FRCS Are there risks? Of course there are! We must never FRCSE FESC FETCS FSAforget, however, that in cardiac surgery we come from an BHF Professor of Cardiac Surgery
Preface to Fourth Edition — 50 years onIn May 1953 Edmund Hilary and Sherpa Tensing became surgery make the clinical perfusionist obsolete? Whateverthe ﬁrst men to stand on the summit of Mount Everest. happens there is no doubt that clinical perfusion will con-In that same month came John Gibbon’s moment of tri- tinue to evolve and develop. We believe that this fourthumph, with the ﬁrst successful use of mechanical car- edition of Techniques in Extracorporeal Circulationdiopulmonary bypass in a human patient. deserves a place on the bookshelves of all healthcare pro- The seed had been sown and it subsequently fell to fessionals working in the cardiac surgical operating room.other pioneers to develop the science of extracorporeal We suspect, in an era of electronic communication, thatcirculation. the bookshelf may well be the ﬁrst to become obsolete. Leeds was at the forefront of this exciting development Progress in surgery is often compared with moun-and, in 1957, Geoffrey Wooler used cardiopulmonary taineering and exploration (and contributors to thisbypass to repair a mitral valve. He then went on to edit the book have themselves used the analogy). A lot has hap-ﬁrst edition of Techniques in Extracorporeal Circulation, pened in both spheres in the past 50 years. With that inpublished in 1976. The change in authorship and content mind, we would like to follow in John Hunt’s illustriousof the subsequent three editions reﬂects the evolution of footsteps and, as he did in The Ascent of Everest, dedicatethe speciality over a generation of cardiac surgery. this book … ‘To those who made it possible’. Who, reading the ﬁrst edition, would have predictedthat the fourth edition, 27 years later, would contain chap- Philip Kay and Chris Munschters on robotic surgery and off-pump surgery? Will the Leedscombined threat of increasing angioplasty and off-pump 2003
Preface to Third EditionThe heart is a unique organ, simple in concept as a mus- The ﬁrst edition of this book, edited by Mr M. Ionescucle pump, but complex in design and function. Heart and Mr G. Wooller 16 years ago, laid a solid foundation forfailure, from whatever cause, remains the commonest the student of extracorporeal circulation. It was followedcause of death in the western world. by a second edition ﬁve years later and, after a further 11 It is now almost 100 years since von Reyn contravened years, by this edition. Yet progress in this ﬁeld is so fast thatthe dictates of Billroth, risked ‘loosing the esteme of many of the new developments in this book were not evenhis colleagues’ and successfully operated on the heart. contemplated in the ﬁnal ‘future developments’ chapter ofHowever, cardiac surgery proceeded at a slow pace until the second edition, and so I am sure will be the case for thethe development of the extracorporeal circuit. Thereafter fourth edition. Similarly, much progress has been madethe understanding of the complex anatomy, biochem- during the three years it has taken to produce this book.istry, pharmacology and physiology of the heart has Nevertheless, this edition, like the original, provides a ﬁrmenabled us to take great strides in the complex repair basis for doctors, nurses, perfusionists and physicians’work that is now so common place in the operating assistants alike, all students of the extracorporeal circula-room. Concomitantly, advances in rheology and material tion and its ever increasing number of applications.science have provided a wider safety margin and there- I hope that it will stimulate its readers to continuingfore expanded the number of patients able to beneﬁt the pioneering interface between the lone surgeon andfrom cardiac surgery. It is these advances that form the the increasingly complex machinery that surrounds him.basis of the third edition of Techniques in ExtracorporealCirculation. P.H. Kay
Preface to Second EditionThe preface to the ﬁrst edition of this book was preceded theoretical aspects of extracorporeal circulation but doesby Michelangelo’s humble remark ‘ancora imparo’. Even not necessarily provide ﬁnal answers.for the contents of this small book on techniques in In an effort to keep abreast of the many advancesextracorporeal circulation it proved its timeless veracity which have occurred, a number of additional topics haveas we ‘continue to learn’. been included in this present edition. Several new, out- The ﬁrst edition, however, despite many short-com- standing contributors have participated, whilst the greatings, has fulﬁlled its role. majority of those chapters which appeared in the ﬁrst During the past few years the energetic clinical and edition have been updated or augmented.research activities have led to many advances and have Despite the awareness of discontinuity and reitera-further broadened the concept of artiﬁcial circulation tion, this second edition of Techniques in Extracorporealand oxygenation so that an increasing number of sub- Circulation retains the structure of most modern booksspecialties are now attaining a certain contour. by being comprised of a series of individual chapters. In recent years, several areas of extracorporeal circula- I wish to express my enthusiasm for the privilege oftion have assumed increasing importance. The progress editing this text and gratefully acknowledge the out-made in the ﬁeld of ischaemic heart disease and the standing contributions of the authors who have joined inmajor impact of myocardial protection through cardio- this endeavour.plegia are only two of the most obvious examples. I should like to thank Miss Wendy Lawrence for theReﬁnements in the construction and performance of complex and seemingly endless secretarial work.bubble oxygenators and the introduction of disposable My sincere appreciation is extended to Messrsmembrane oxygenating systems have changed the tech- Butterworths for their unfailing attention to detail andniques of heart–lung bypass and broadened its scope. for the maintenance of the high standards for which they Many pioneers in these ﬁelds have discovered and redis- are known.covered noteworthy features of great clinical signiﬁcance. This second edition attempts to summarize the majortechnical problems and touches on some of the more Marian I. Ionescu
Preface to First Editionancora imparo single volume standard current techniques in extracorpor-Michelangelo Buonarotti eal circulation along with the more recent developments in this ﬁeld. This is an attempt to answer some of theExtracorporeal circulation with an artiﬁcial heart-lung innumerable practical problems associated with the rou-machine has established itself as the routine adjunct to tine use of artiﬁcial circulation and oxygenation and tointracardiac and vascular surgery. Since its introduction present some models of standardized techniques.in 1953, this method has been progressively improved by A major problem with such a book is to decide what todevelopment and simpliﬁcation of the equipment and by include and what to omit. We are aware that omissionsbetter understanding of the body response to the alter- have been made, but we have aimed to keep the subjectations induced by the use of artiﬁcial perfusions. matter strictly circumscribed in the interest of text size and The method, established in the experimental labora- readability. The esoteric has been omitted on purpose andtory, has been perfected by clinical use. For many poorly emphasis is placed on the current practical methodology.understood aspects the method has continued to be Advances in modern surgical and perfusion techniquesinvestigated in the laboratory, where answers and solu- have been developed to such a degree that an entirely newtions have been found for innumerable bewildering and spectrum of problems evolves with each new develop-knotty clinical problems. ment. Such rapid changes and improvements will certainly A superﬁcial look at today’s methods would give the call for another publication in the near future, and this isuninformed the general impression that no substantial another reason for limiting the size of this book.progress has been made in the past ten years. For example, Since this is a multi-authored book and the chaptersthe same principle of bubble oxygenation used at the begin- are designed to be read separately, some reiteration hasning of the open-heart surgery era is almost universally been inevitable, although an attempt was made to avoidemployed today. The same may be said for metallic pros- repetition.thetic valves with a ball or disc occluder mechanism. The Major attention has been focused on the cardio-vascularbest method for ‘myocardial preservation’ during open- system, the lung, the renal function and haematologicalheart surgery is yet to be established and the Montagues of changes. Clearly the brain, liver, gut, muscle masses andhypothermia still have to convince the Capulets of coronary reticuloendothelial system are of great importance in theperfusion of the veracity and superiority of their principle body response to extracorporeal circulation, but the meas-just as much as they had to ten years ago. urement of their function in the cardiovascular patient is On closer examination, one realizes that during the at the moment largely in the realm of the investigator.past ten years an enormous wealth of data and knowledge Although the principles and techniques described havehas been accumulated and the application of this know- become routine for practical purposes, they are by noledge has made clinical perfusions incomparably better means beyond challenge. As William Hazlitt put it ‘whenand safer. The results of cardiovascular surgery obtained a thing ceases to be a subject of controversy, it ceases to betoday, whether in the newborn or the elderly, for great a subject of interest’.arteries or coronary arteries, in routine cases or in emer- The Editors join the contributors in hoping that thisgencies, when compared with the results obtained only volume will be of interest to those active in the ﬁeld often years ago, are the best proof of progress and continu- cardiovascular surgery.ous improvement in extracorporeal circulation. We take great pleasure in expressing our thanks to During the past few years many new and exciting prin- Dr Frank Gerbode for kindly writing the Foreword ofciples and techniques based on extracorporeal circulation this work. We are grateful to Miss Nancy Evans for herhave been brought into clinical use. Deep hypothermia for continuous and enthusiastic help.heart surgery in the newborn, prolonged extracorporeal Completion of this book within a few months wasoxygenation-perfusion for pulmonary insufﬁciency and promised, but it has taken almost two years and weintra-aortic balloon pumping for circulatory assistance are appreciate the forbearance and continuous help of oursome of the major achievements of the past decade. publishers, Butterworth and Co. Ltd. The paucity of books devoted exclusively to extracor-poreal circulation has prompted us to bring together in a M.I. Ionescu
AcknowledgementsPhilip H Kay and Christopher M Munsch would like to We are also indebted to everyone at Hodder Arnold whothank the individual chapter authors for their skilful and worked so hard to make it happen.patient contributions to this beautifully crafted book.
1A brief history of bypassANIL KUMAR MULPUR AND CHRISTOPHER M MUNSCHIntroduction 1 Hypothermia 4The ﬁrst heart–lung machine 1 Heparin 4Oxygenation 2 Summary 5Pumping the blood 4 Further reading 5Haemodilution 4 References 5INTRODUCTION THE FIRST HEART–LUNG MACHINEThe history of cardiopulmonary bypass is, in many ways, The concept of cardiopulmonary bypass is rightlya miniature representation of the history of all surgery. credited to Dr John Heysham Gibbon Jr (1903–1973).The discoveries and the experiments, the longed-for Dr Gibbon came from a family of doctors and was work-triumphs and the all too frequent disasters, the blood ing with Dr Churchill at Harvard Medical School. In(especially the blood), the sweat and the tears of years of October 1930 a female patient, who had undergonesurgical endeavour are all mirrored in the evolution of a cholecystectomy two weeks before, collapsed due tocardiac surgery. In 1880 Billroth stated that ‘any surgeon pulmonary thrombo-embolism. Dr Churchill did under-who wishes to preserve the respect of his colleagues, take a pulmonary embolectomy on her, but in that erawould never attempt to suture the heart’. What was once there were no survivors of this procedure in the USA.considered hazardous, outrageous or even sacrilegious Dr Gibbon looked after this patient in her last stages.has now become routine and commonplace. There is no This led to the genesis of an idea that Dr Gibbon outlineddoubt that the bravery and determination of the pion- (Gibbon, 1970):eers (both doctors and patients) has seen bypass developrapidly. Most cardiac surgeons these days prefer their During that long night, helplessly watching the patientheart surgery to be, if not boring, then at least not too struggle for life as her blood became darker and veinsexciting. more distended, the idea naturally occurred to me that if Much has been written about the history of cardio- it were possible to remove continuously some of the bluepulmonary bypass and the development of cardiac sur- blood from the patient’s swollen veins, put oxygen intogery. The interested reader, particularly one with an eye that blood and allow carbon dioxide to escape from it,for the ﬂamboyant, is recommended to study Landmarks and then to inject continuously the now-red blood backin Cardiac Surgery (Westaby and Bosher, 1997). This into the patient’s arteries, we might have saved her life.chapter could never compete in such exalted company We would have bypassed the obstructing embolus andand, in fact, subsequent chapters in the current book performed part of the work of the patient’s heart andwill cover the historical background to speciﬁc areas of lungs outside the body.bypass in greater detail. Therefore, this introductorychapter will simply document some of the major mile- Dr Gibbon set out to devise a mechanical pump oxy-stones in the (relatively short) journey from impossible genator and, with his wife Mary Hopkinson, spent theto mundane. next 20 years in pursuit of his goal. The heart–lung
2 A brief history of bypassmachine Model I was built by International Business carbon dioxide removal. It seemed that what was actuallyMachines (IBM) laboratories in 1949, by which time needed was in fact a lung, either natural or artiﬁcial.Gibbon was able to keep small dogs on bypass with only10 per cent mortality, and by 1951 a machine for clinicaluse was built. In 1953, using Model II, an atrial septal defect The lungswas closed successfully on cardiopulmonary bypass, forthe ﬁrst time in history. In 1956, Campbell reported successful cardiac surgical However, this momentous occasion had much of procedures in humans on bypass, by use of dog lungsthe feel of a false dawn. Gibbon operated on four further (Campbell et al., 1956), and Mustard and co-workerspatients, all of whom died. He became disillusioned with reported the use of scrupulously washed monkey lungsthe technique and critical of his own surgical abilities, for oxygenation in human cardiac surgery in 1954. Theseand called a halt to the programme. experiments, although seemingly moderately successful, All was not lost though, and John Kirklin, using a were extremely complicated and soon abandonedmodiﬁed Model II, operated on eight patients with intra- (Mustard et al., 1954; Mustard and Thomson, 1957). Incardiac defects, with just four deaths, only one of which 1958 Drew used patients’ own lungs as the oxygenator,he attributed directly to complications of bypass. The with a combination of right and left heart bypass andimpetus had been regained and further progress in profound hypothermia (Drew and Anderson, 1959). Withmechanical cardiopulmonary bypass was stimulated. this technique, the time available for surgical repair was increased and more complex abnormalities could be addressed (Westaby and Bosher, 1997).OXYGENATIONThe historical development of oxygenators is summar- Cross-circulationized in Fig. 1.1. Many methods of oxygenating the bloodhave been investigated over the years. Early experiments Andreasen and Watson conducted some canine experi-involved actually injecting oxygen directly into the blood ments in Kent, England and published their resultsstream, whilst other equally inventive techniques of oxy- in 1952. If the superior vena caval entry into the heartgenation were attempted and soon abandoned. These was snared at the cavo-atrial junction, no dog survivedearly experiments focused purely on artiﬁcial oxygen- beyond 10 minutes. If the snare was distal to azygos vein,ation, without concerning themselves with the need for allowing azygos venous ﬂow into the right atrium, there Oxygenators Natural Artificial oxygenators oxygenators Heterologous Homologous oxygenators oxygenators Dog Monkey lungs lungs Controlled cross-circulation Bubble Film Membrane Figure 1.1 Development of oxygenators for oxygenator oxygenator oxygenator cardiopulmonary bypass.
Oxygenation 3was adequate ﬂow to prevent cerebral damage for up to sheet oxygenator, and improved the DeWall–Lillehei40 minutes. This ﬁnding challenged the existing notion bubble oxygenator further, which meant that the bub-that ﬂows equivalent to normal cardiac output were nec- ble oxygenator became available as a sterile sealed unit.essary to prevent damage to vital centres, and suggested This development played a signiﬁcant role in expandingthat in fact only eight to nine per cent of normal ﬂow was cardiac surgery beyond Minnesota (Gott et al., 1957a,b).needed (Andreasen and Watson, 1952). Naef (1990) wrote: Lillehei, at the University of Minnesota, recognizedthe signiﬁcance of these ﬁndings for cardiac surgery the home made helix reservoir bubble oxygenator of(Lillehei, 2000). After a series of careful experiments DeWall and Lillehei, ﬁrst used clinically on May 13, 1955,(Cohen and Lillehei, 1954), he introduced the technique went to conquer the world and helped many teams toof ‘controlled cross-circulation’. As the name suggests, embark on the correction of malformations inside thethe technique used an adult whose circulation was con- heart in a precise and unhurried manner. The road to open-nected to a child patient, the adult subject acting as the heart surgery had been opened.oxygenator. In Lillehei’s own words, ‘controlled’ refers tothe use of a pump to precisely control the balance of the DeWall went on to develop the bubble oxygenator fur-volume of blood ﬂowing into and out of the donor and ther and introduced the oxygenator and omnithermicthe patient. heat exchanger in a disposable and pre-sterilized poly- This was a daring and innovative idea. These oper- carbonate unit (DeWall et al., 1966). With the advent ofations carried a theoretical 200 per cent mortality. In fact, better technology, and safer operations under more con-there was no donor mortality in 45 operations. Of 45 trolled circumstances, surgeons were, for the ﬁrst time,patients, 28 survived and were discharged from hospital, appreciating the intricacies of pathologic anatomy inmany surviving for as long as 30 years (Lillehei et al., congenital and acquired heart disease, and leading to the1986). Controlled cross-circulation, however, was limited development of surgical techniques in the present form.in its use and could not fully support the circulation. Atthe same time, more conventional forms of extracorporealcirculation were being developed, and before long Lillihei Film oxygenatorshimself went on to develop a new pump oxygenator. Gibbon developed a ﬁlm oxygenator with a rapidly revolving vertical cylinder. The ﬁlm itself was a thin ﬁlmBubble oxygenators of blood on the metal plate, where the oxygenation took place. In the ﬁrst model, there was no reservoir. Gas ﬂowSimple measures to bubble oxygen into the blood met included a 95 per cent oxygen and ﬁve per cent carbonwith disastrous results because of air embolism. Clark and dioxide mixture at 5 L/min. The venous and arterial sidesco-workers had a breakthrough in 1950, when they started of the oxygenators had roller pumps and blood passedto use small glass beads or rods coated with DC Antifoam through tubing, which was immersed in a waterbathA, made by the Dow Corning Company in Michigan to maintain a constant temperature throughout the per-(Clark et al., 1950). This concept was further developed by fusion. Flows of up to 500 mL/min were generated withLillehei and DeWall, who used a spiral settling tube with a the initial model (Gibbon, 1937). Next, a wire mesh washelical system that largely eliminated bubbles. The initial introduced to produce a turbulent blood–gas interfacemodels were sterilized and re-used. Later on, disposable to improve oxygenation (Gibbon, 1954). This was fur-bubble oxygenators were developed. The ﬁrst clinical use ther improvised at the Mayo Clinic, with 14 wire meshesof the DeWall–Lillehei bubble oxygenator was on 13 May enclosed in a lucite case. Blood ﬂowed onto the screens1955, for a three-year-old child with a ventricular septal through a series of 0.6 micron slots. Gas ﬂow was 10 L ofdefect and pulmonary hypertension. By use of normo- oxygen, and the carbon dioxide ﬂow was varied depend-thermia, a Sigmamotor pump and ﬂows of 25–30 mL/kg, ing on the pH of the blood (Kirklin et al., 1955). However,Lillehei reported the ﬁrst success story with the bubble compared with the DeWall–Lillehei bubble oxygenator,oxygenator (Lillehei et al., 1956). the Mayo Clinic Gibbon ﬁlm oxygenator, although impres- Bubble oxygenators were later reﬁned to serve adult sive, was handcrafted and expensive, and difﬁcult to usepatients. The Rygg–Kyvsgaard bag (Rygg and Kyvsgaard, and maintain.1956) combined the bubbling and settling chambers Kay and Cross developed a rotating disk ﬁlm oxygena-with a reservoir, all in one plastic bag. Sponges made of tor in Cleveland, USA. Although this device did becomepolyethylene and coated with antifoam agent were used commercially available, it had serious drawbacks infor bubble removal. This model was manufactured in terms of ease of use, massive priming volumes, and difﬁ-Denmark. Up to 3 L/min ﬂows were possible. Gott and culty in cleaning and sterilizing (Cross et al., 1956; Kayco-workers developed a self-contained unitized plastic et al., 1956).
4 A brief history of bypassMembrane oxygenators priming of the cardiopulmonary bypass circuits. DeWall and Lillehei subsequently conﬁrmed the beneﬁts ofBy 1944, Kolff had reﬁned a cellophane membrane appar- haemodilution on cardiopulmonary bypass (DeWall andatus for dialysis as an artiﬁcial kidney. He later tried to Lillehei, 1962; DeWall et al., 1962; Lillehei, 1962). Despiteuse this as a membrane oxygenator, but found it to be abundant literature, the actual degree of acceptableinefﬁcient (Kolff and Berk, 1944; Kolff and Balzer, 1955). haemodilution remains controversial even today.However, Clowes and Neville developed a teﬂon mem-brane oxygenator for human usage in 1957. The mem- HYPOTHERMIAbrane area was 25 m2, but the oxygenator was bulky withproblems of sterilization and assembly (Clowes andNeville, 1957). Once silicone became available as a mem- Historically, it is interesting to note that hypothermiabrane with satisfactory permeability to both oxygen and usage in cardiac surgery precedes the development ofcarbon dioxide, Bramson and colleagues (Bramson et al., cardiopulmonary bypass. Following his earlier work on1965) reported a new disposable membrane oxygenator the treatment of frostbite, William Bigelow had alreadywith integral heat exchanger. This model had 14 cells, done extensive experimental work on dogs on the physio-each having a silicone rubber membrane across which logical effects of hypothermia (Bigelow et al., 1950). Hediffusion took place. Bodell et al. (1963) proposed the predicted the possible use of hypothermia in cardiacuse of tubular capillary membranes instead of ﬁlm, and surgery thus:this notion led to the hollow-ﬁbre membrane oxygen- The use of hypothermia as a form of anesthetic couldators. Not to be outdone, Lillehei was also associated with conceivably extend the scope of surgery in many newthe availability of the ﬁrst compact, disposable and directions. A state in which the body temperature is low-commercially manufactured membrane oxygenator for ered and the oxygen requirements of tissue are reduced toclinical use (Lande et al., 1967). a small fraction of normal would allow exclusion of organs from the circulation for prolonged periods. Such a technic might permit surgeons to operate upon the ‘bloodlessPUMPING THE BLOOD heart’ without recourse to extra corporal pumps, and perhaps allow transplantation of organs.A critical component of the heart bypass apparatus is These experiments soon led to the use of hypothermiasome form of efﬁcient atraumatic mechanical pump. A alone, with inﬂow occlusion but without cardiopul-variety of pumping devices was developed before the dou- monary bypass, for the treatment of atrial septal defects.ble roller pump became widely used. Dale and Schuster On 2 September, 1952 Dr F. John Lewis and his team(1928) developed a diaphragm pump with valved inlet closed an ostium secundum atrial septal defect in a ﬁve-and outlet ports, but a single pump could not generate year-old girl on inﬂow occlusion and moderate totalsufﬁcient ﬂow, so Jongbloed used six pumps of this type in body hypothermia.parallel to conduct cardiopulmonary bypass (Jongbloed, Gollan should be given the credit of working on1949). In Minnesota, Lillehei’s group initially used a mul- the concept of combining hypothermia and cardiopul-ticam activated sigmamotor pump. monary bypass, before either actually became clinically However, as early as 1934, DeBakey had modiﬁed a applicable (Gollan et al., 1955). Sealy, of Duke University,previously available Porter–Bradley roller pump for rapid North Carolina, USA, subsequently employed a combin-blood transfusion (DeBakey, 1934). This pump was applied ation of cardiopulmonary bypass and hypothermia forto cardiopulmonary bypass, and rapidly became – and the ﬁrst time in a clinical situation for closure of atrialremains – the most common type of pump in use for septal defect and this operation lasted for seven hoursclinical perfusion. and 15 minutes! By 1958, Sealy reported a series of 49 patients operated on by the combined technique (Sealy et al., 1958). As mentioned previously, Drew took theHAEMODILUTION temperature down to 12–15°C and pioneered the con- cept of circulatory arrest for cardiac surgery (Drew andTwo major problems were identiﬁed in patients after car- Anderson, 1959).diopulmonary bypass, namely ‘post-perfusion syndrome’and ‘homologous blood syndrome’. In the early daysthe oxygenators and the circuit were primed with donor HEPARINblood. Zuhdi et al. (1961a, 1961b), however, developedthe concept of haemodilution with ﬁve per cent dextrose It is almost impossible to imagine the conduct ofand thus began the usage of clear priming or crystalloid cardiopulmonary bypass without the use of heparin.
References 5The discovery of heparin is an interesting story (Jaques, REFERENCES1978), and in the history of medicine is quoted as a classi-cal example of ‘serendipity’. Horace Well coined this term Andreasen, A.T., Watson, F. 1952: Experimental cardiovascularin 1754; ‘The Three Princes of Serendip’, was the title of a surgery. British Journal of Surgery 39, 548–51.fairy tale in which the heroes were always making fortu- Bigelow, W.G., Lindsay, W.K., Greenwood, W.F. 1950: Hypothermia:nate discoveries (Concise OED, 2002). McLean was a med- its possible role in cardiac surgery. An investigation of factorsical student working with W. H. Howell in 1916, on the governing survival in dogs at low body temperatures. Annals ofnature of ether soluble procoagulants, and by chance dis- Surgery 132, 849–66.covered a phospholipid anti-coagulant. Some years later Bodell, B.R., Head, J.M., Head, L.R. 1963: A capillary membranea water-soluble mucopolysaccharide was identiﬁed by oxygenator. Journal of Thoracic and Cardiovascular Surgery 46,Howell, and this proved to be heparin (McLean, 1959). 639–50.Even today, except in very rare circumstances, where it Bramson, M.L., Osborn, J.J., Main, F.B. et al. 1965: A newcannot be used, because of genuine hypersensitivity or disposable membrane oxygenator with integral heat exchanger. Journal of Thoracic and Cardiovascular Surgery 50,heparin-induced thrombocytopenias, heparin and car- 391–400.diopulmonary bypass are inseparable. Campbell, G.S., Crisp, N.W., Brown, E.B. Jr. 1956: Total cardiac bypass in humans utilising a pump and heterologous lung oxygenator (dog lung). Surgery 40, 364–71.SUMMARY Clark, L.C., Gollan, F., Gupta, V.B. 1950: The oxygenation of blood by gas dispersion. Science III, 85–7. Clowes, G.H.S., Neville, W.E. 1957: Further development of a bloodThe history of cardiopulmonary bypass is a truly fascinat- oxygenator dependent upon the diffusion of gases throughing story. Against many difﬁculties, with a combination plastic membranes. Transactions of the American Society forof perseverance, intellect and skill, the early pioneers Artiﬁcial Internal Organs 3, 53–8.developed the art of cardiopulmonary bypass as we see Cohen, M., Lillehei, C.W. 1954: A quantitative study of the ‘azygosit today. A large range of congenital and acquired heart factor’ during vena caval occlusion in the dog. Surgery,diseases can be treated surgically with the aid of cardiopul- Gynecology and Obstetrics 98, 225–32.monary bypass. With advancing technology, cardiopul- Concise Oxford English Dictionary (Tenth edition). 2002: Oxford:monary bypass continues to develop. Advances such as Oxford University Press.heparin-bonded circuits, methods minimizing systemic Cross, F.S., Berne, R.M., Hirose, Y. et al. 1956: Description andinﬂammatory response, percutaneous applications of evaluation of a rotating disc type reservoir oxygenator.bypass, port access surgery, continued improvement in Surgical Forum 7, 274–8. Dale, H.H., Schuster, E.A. 1928: A double perfusion pump. Journaloxygenators and ventricular assist devices; all these and of Physiology 64, 356–64.others will change the picture of cardiopulmonary bypass DeBakey, M.E. 1934: A simple continuous ﬂow blood transfusionbeyond recognition, and the present day will then become instrument. New Orleans Med Surg J 87, 386–9.the history. DeWall, R., Lillehei, C.W. 1962: Simpliﬁed total body perfusion- reduced ﬂows, moderate hypothermia and hemodilution.Key early events in the development of Journal of the American Medical Association 179, 430–4. DeWall, R., Lillehei, C.W., Sellers, R. 1962: Hemodilution perfusionextracorporeal circulation for open heart surgery. New England Journal of Medicine 266, 1078–84.• 1916: McLean; discovery of heparin. DeWall, R.A., Bentley, D.J., Hirose, M. et al. 1966: A temperature• 1930: Gibbon; initial idea of cardiopulmonary bypass. controlling (omnithermic) disposable bubble oxygenator for• 1934: DeBakey; concept of roller pump for total body perfusion. Diseases of the Chest 49, 207–11. extracorporeal circulation. Drew, C., Anderson, I.M. 1959: Profound hypothermia in cardiac• 1950: Bigelow; profound hypothermia for open- surgery. Lancet April 11: 748–50. heart surgery. Gibbon, J.H. Jr. 1937: Artiﬁcial maintenance of circulation during• 1953: Gibbon; ﬁrst successful clinical use of experimental occlusion of pulmonary artery. Archives of Surgery 34, 1105–31. cardiopulmonary bypass. Gibbon, J.H. Jr. 1954: Application of mechanical heart and• 1954: Lillehei; use of controlled cross-circulation. lung apparatus to cardiac surgery. Minnesota Medicine 37, 171–80. Gibbon, J.H. Jr. 1970: The development of the heart–lungFURTHER READING apparatus. Rev Surg 27, 231–44. Gollan, F., Phillips, R., Grace, J.T. et al. 1955: Open left heart• General reading: Westaby, S., Bosher, C. 1997: Landmarks in surgery in dogs during hypothermic asystole with and without cardiac surgery. Oxford: ISIS Medical Media, 1997. A very extracorporeal circulation. Journal of Thoracic Surgery 30, well-written book on the history of cardiac surgery. 626–30.
6 A brief history of bypassGott, V.L., DeWall, R.A., Paneth, M. et al. 1957a: A self contained, Lillehei, C.W., DeWall, R.A., Read, R.C. et al. 1956: Direct vision disposable oxygenator of plastic sheet for intracardiac surgery. intracardiac surgery in man using a simple, disposable artiﬁcial Thorax 12, 1–9. oxygenator. Diseases of the Chest 29, 1–8.Gott, V.L., Sellers, R.D., DeWall, R.A. et al. 1957b: A disposable Lillehei, C.W., Varco, R.L., Cohen, M. et al. 1986: The ﬁrst open heart unitized plastic sheet oxygenator for open heart surgery. repairs of ventricular septal defect, atrioventricular communis, Diseases of the Chest 32, 615–25. and tetralogy of Fallot using extracorporeal circulation by crossJaques, L.B. 1978: Addendum: the discovery of heparin. Seminars in circulation: a 30 year follow up. Annals of Thoracic Surgery Thrombosis and Hemostasis 4, 350–3. 41, 4–21.Jongbloed, J. 1949: The mechanical heart/lung system. Surgery, McLean, J. 1959: The discovery of heparin. Circulation XIX, 75–78. Gynecology and Obstetrics 89, 684–91. Mustard, W.T., Thomson, J.A. 1957: Clinical experience with theKay, E.B., Zimmerman, H.A., Berne, R.M. et al. 1956: Certain clinical artiﬁcial heart–lung preparation. Journal of the Canadian aspects in the use of the pump oxygenator. Journal of the Medical Association 76, 265–9. American Medical Association 162, 639–41. Mustard, W.T., Chute, A.L., Keith, J.D. et al. 1954: A surgicalKirklin, J.W., Dushane, J.W., Patrick, R.T. et al. 1955: Intracardiac approach to transposition of the great vessels with surgery with the aid of a mechanical pump oxygenator system extracorporeal circuit. Surgery 36, 39–51. (Gibbon type): report of eight cases. Proceedings of Staff Naef, A.P. 1990: The story of thoracic surgery. Toronto: Hografe & Meetings of the Mayo Clinic 30, 201–7. Huber, 113–19.Kolff, W.J., Balzer, R. 1955: The artiﬁcial coil lung. Transactions Rygg, H., Kyvsgaard, E. 1956: A disposable polyethylene oxygenator of the American Society for Artiﬁcial Internal Organs 1, system applied in the heart/lung machine. Acta Chirurgica 39–42. Scandinavica 112, 433–7.Kolff, W.J., Berk, H.T.J. 1944: Artiﬁcial kidney: dialyser with a great Sealy, W.C., Brown, I.W., Young, W.G. 1958: A report on the use of area. Acta Medica Scandinavica 117, 121–34. both extracorporeal circulation and hypothermia for open-heartLande, A.J., Dos, S.J., Carlson, R.G. et al. 1967: A new membrane surgery. Annals of Surgery 147, 603–13. oxygenator–dialyser. Surgical Clinics of North America 47, Westaby, S., Bosher, C. 1997: Landmarks in cardiac surgery. Oxford: 1461–70. ISIS Medical Media.Lillehei, C.W. 1962: Hemodilution perfusion for open heart surgery. Zuhdi, N., McCollough, B., Carey, J. et al. 1961a: Hypothermic Use of low molecular weight dextran and ﬁve per cent dextrose. perfusion for open heart surgical procedures – report of the use Surgery 52, 30–31. of a heart–lung machine primed with ﬁve per cent dextrose inLillehei, C.W. 2000: Historical development of cardiopulmonary water inducing hemodilution. J Int Coll Surg 35, 319–26. bypass in Minnesota. In: G.P. Gravlee et al. (eds), Zuhdi, N., McCollough, B., Carey, J. et al. 1961b: Double helical Cardiopulmonary bypass: principles and practice reservoir heart–lung machine designed for hypothermic (second edition). Baltimore, MD: Lippincott Williams & perfusion primed with ﬁve per cent glucose in water inducing Wilkins, 3–21. hemodilution. Archives of Surgery 82, 320–5.
2Design and principles of the extracorporeal circuitMEDTRONIC, INC., A MANUFACTURER OF TECHNOLOGIES FOR EXTRACORPOREAL CIRCULATIONHistory of cardiopulmonary bypass 7 Heat exchangers 14Bubble oxygenators 8 Tubing 15Membrane oxygenators 8 Myocardial protection 15Components of the extracorporeal circuit 9 Biocompatibility 16Pumps 9 Adequacy of perfusion 21Venous reservoir 12 Acknowledgements 21Cardiotomy reservoirs 13 References 21 the extracorporeal circuit are adequately perfused KEY POINTS with oxygenated blood by continual monitoring of blood ﬂow rate, perfusion pressure, acid/base state, oxygen consumption, coagulation and renal • The essential components of the clinical function. extracorporeal circuit are a pump (artiﬁcial heart), an oxygenator (artiﬁcial lung), a reservoir and the tubing to connect these devices, although systems are now emerging without traditional reservoirs. HISTORY OF CARDIOPULMONARY BYPASS • Additional components include a heat exchanger, a system for myocardial protection, and gas and emboli ﬁlters. Secondary suction circuits may be The ﬁrst proposal for artiﬁcial circulation was put for- added for salvaging shed blood, and venting the ward by Le Gallois in 1812 when he perfused rabbit heart. brains through carotid arteries. Between 1848 and 1853 • The current generation of membrane oxygenators Brown Sequard showed that dark venous blood, when incorporating reservoirs and heat exchangers exposed to air and shaken, turned bright red. He further provide safety, efﬁcacy and ease of use. demonstrated the feasability of perfusing isolated brain • Centrifugal pumps are compact, durable, easy to specimens with this ‘arterialized’ blood. The ﬁrst bubble set up and cause minimal haemolysis compared oxygenator, utilizing the same principle of mixing venous with roller pumps. While their cost is certainly blood with air, was assembled by Shroder in 1882. And higher than a simple length of roller pump tubing, then, two years later, von Frey and Gruber created the ﬁrst it may be more than offset by savings in ventilatory membrane oxygenator, in which the direct blood–air and ICU time, as well as overall hospital stay. interface of the bubbler design was avoided. • A body of published evidence, as well as extensive In 1900, Howell and colleagues discovered the anti- clinical experience by surgeons and perfusionists, coagulant properties of heparin. Without the risk of cata- supports the value of heparin-based biosurfaces strophic clotting within the bypass circuit, it was now for thrombo-resistance and biocompatibility possible to expose the blood to extended periods of during extracorporeal circulation. extracorporeal circulation. • It is the responsibility of the perfusionist to The ﬁrst clinical application of extracorporeal circula- ensure that the organs of the body supported by tion was performed by Dr John Gibbon, Massachusetts
8 Design and principles of the extracorporeal circuit Table 2.1 Developmental history of oxygenators Non-membrane oxygenators 1937 Gibbon Blood ﬁlter – pulmonary embolus 1951 Dennis/Bjork Rotating screen and cardiopulmonary bypass rotating disk 1955 Lillehei/DeWall First bubble oxygenator with helix reservoir 1956 Kay/Cross Reﬁnd disk oxygenator for up to 4000 mL of venous blood 1956 Rygg/Kyvsgaard First disposable plastic bag oxygenator, Polystan (Rygg Bag) 1962 Cooley/Beall Proposed use of commercially available disposable bubble oxygenators (Travenol Bag) 1966 DeWall/Najafe/Roden First disposable hard shell oxygenator (polycarbonate) with built-in heat exchanger (Bentley Labs) Membrane oxygenators 1955 Kolff/Balzfer Oxygenated blood through polyethylene membrane (animals) 1956 Kolff First coiled polyethylene tube oxygenator 1958 Clowes First to test Teﬂon as membrane plate oxygenator 1968 Lande Methyl silicone folded plate membrane oxygenator (Lande/Edwards) 1969 Pierce Co-polymer of dimethyl siloxan and polycarbonate 1969 Pierce Pierce-GE 1971 Kolobow Silicone rubber reinforced by nylon mesh rolled or coiled (SciMed–Kolobow) 1972 Eiseman/Spencer Expanded (Teﬂon) membrane sheets (Travenol/TMO) 1975 Travenol Labs Polypropylene (expanded) plate or sheets (TMO) 1985 J& J Cardiopulmonary First hollowﬁbre polypropylene oxygenator (Maxima)General Hospital who, in 1953, successfully repaired an into the bubble chamber. The early Bentley model hasatrial septal defect in a young female. Despite subsequent the heat exchanger located within the arterial reservoir.setbacks, Dr C Walton Lillehei of the University of Bubble oxygenators are efﬁcient and easy to use. Unfor-Minnesota and several others persevered in further tunately, the nature of the foaming/defoaming processdeveloping the techniques and equipment, with Lillehei causes signiﬁcant haemolysis, which becomes clinicallyusing the ﬁrst bubble oxygenator in 1955. signiﬁcant after only a few hours. Bubble oxygenators also The bubble oxygenator, ﬁrst developed by Rygg, was present a higher risk of micro- and macro-air embolism:produced commercially by 1956. The years since have seen the defoaming process is imperfect, and inadvertentmyriad reﬁnements and improvements in oxygenator and emptying of the arterial reservoir can lead to massiveother component designs, which unlike the early systems amounts of air being pumped directly to the patient, atare now completely disposable. A brief history of the least when roller pumps are used. Further, because of thedevelopment of oxygenators is summarized in Table 2.1. bubbling process, it is not considered safe to blend oxy- gen with air (since nitrogen bubbles would be so much less soluble) making independent control of pO2 andBUBBLE OXYGENATORS pCO2 impossible. This would also necessitate the mixing of small amounts of carbon dioxide with the oxygen toBubble oxygenators were the ﬁrst design to be commer- prevent the pCO2 from falling too far. For these reasons,cially available in completely disposable form, and were bubblers are rarely used today. Several safe, efﬁcientin wide use throughout the world for more than 46 years. membrane oxygenators currently dominate the market.A ‘bubbler’ usually consists of an integrated design, incorp-orating the oxygenator, heat exchanger, arterial reservoir MEMBRANE OXYGENATORSand cardiotomy ﬁlter in one unit. The unit functions bypassing incoming venous blood over a perforated orporous sparger plate, through which oxygen is passed, Membrane oxygenators of various designs have beenturning the venous blood into a foam of variously sized used sporadically since the mid-1950s, but it was notbubbles. As oxygen diffuses across the bubble surfaces until 19 years ago that relatively low-prime volume, easy-into the blood, and conversely, as excess carbon dioxide to-use units became commercially available. In the mem-diffuses from the blood into the bubbles, the blood is brane oxygenator, the ventilating gas is separated from thearterialized. The blood is then passed through a silicone- blood by a semi-permeable membrane fabricated frombased defoaming medium, collects in an arterial reser- polypropylene, or in one case, silicone rubber. Unlike bub-voir section and is returned to the patient. The heat ble oxygenators, there is no direct contact between theexchanger in most bubble oxygenators was incorporated blood and ventilating gas. Gas exchange is accomplished