Surgical setup for cardiopulmonary bypass through central cannulation

The introduction of cardiopulmonary bypass was one of the most important clinical advances of 1952. In that year, John Gibbon performed the first successful cardiac surgery using cardiopulmonary bypass. The procedure has been described as “One of the most impressive evidences of the role of investigative surgery in the history of medicine in the persevering efforts of Dr. Gibbon for more than 20 years, which finally culminated in a practical heart-lung machine”, at the first John H. Gibbon, Jr. Lecture at the annual meeting of the American College of Surgeons. Due to on-going advancements in cardiopulmonary bypass, many patients with complex heart disease requiring surgical care undergo cardiac surgery while the other organs remain adequately oxygenated and perfused. This tutorial discusses the access, surgical technique, and initiation of cardiopulmonary bypass through central cannulation and describes the safeguards and pitfalls.

Weaning from cardiopulmonary bypass, decannulation, and closure

In 1952, John Gibbon performed the first successful cardiac procedure using cardiopulmonary bypass, which turned out to be one of the most important clinical advances of that year. Cardiopulmonary bypass has also been described as “One of the most impressive evidences of the role of investigative surgery in the history of medicine in the persevering efforts of Dr. Gibbon for more than 20 years, which finally culminated in a practical heart-lung machine,” at the first John H. Gibbon, Jr, Lecture at the annual meeting of the American College of Surgeons [1]. Due to the subsequent advancement of cardiopulmonary bypass, many patients with complex heart disease requiring surgical care undergo cardiac surgery while the other organs remain adequately oxygenated and perfused.

Cardioplegia Application with A Hand-Squeezed Cardioplegia Bag. Is It Safe?

Objectives: Cardioplegia solutions have a role not only in arresting the heart but also in protecting the myocardium from ischemia. While antegrade cardioplegia is given by the heart-lung machine in many centers, it is given by a hand-squeezed bag in very few centers. The pressure of cardioplegia given antegrade from the heart-lung machine is certain (60-90 mmHg). The pressure applied in the cardioplegia method, which is given antegrade with a hand-squeezed bag, is uncertain and variable. We compared the antegrade cardioplegia method applied with a hand-squeezed bag with the antegrade cardioplegia method applied with a roller pump from the heart-lung machine in terms of protecting the myocardium from ischemia. Methods: Seventy-six patients who did not have an acute myocardial infarction, had normal preoperative cardiac marker (troponin and CK-MB) values, did not undergo redo open heart surgery, had an ejection fraction of 50% and above, and underwent elective two or three-vessel isolated coronary artery bypass surgery were evaluated. While tepid (30-32°C) blood cardioplegia was administered antegrade to 33 patients (Group A) with a hand-squeezed bag, the other 34 patients (Group B) received tepid (30-32°C) antegrade blood cardioplegia from the heart-lung machine. The perioperative and postoperative data of the patients were recorded and compared. To evaluate myocardial damage, postoperative cardiac markers and echocardiography data were evaluated and compared at the fourth hour after the cross-clamp was removed in both groups. Results: When evaluated in terms of preoperative demographic data, preoperative mean EF values and intraoperative data, there was no statistical difference between both groups. When we evaluated in terms of myocardial protection, the mean TnT level was 4.31 ± 1.95 at the 4th hour in Group A and 3.91 ± 1.69 in Group B. Mean 4th hour CK-MB level was 40.84 ± 9.07 in Group A and 38.56 ± 8.07 in Group B. Mean change in EF (%) was -4.09 ± 4.41 in Group A and 3.53 ± 4.53 in Group B. In line with the current data when we evaluated in terms of myocardial protection, we found that there is no statistical difference between the two groups (P = 0.373; P = 0.158; P = 0.523). There was no statistical difference between both groups, in terms of postoperative arrhythmias. None of the patients died, and no patients required an intra-aortic balloon pump. Results: As a result of our study, cardioplegia administration with a certain constant pressure from the roller pump and hand-squeezed bag with uncertain pressure does not make a difference, in terms of myocardial protection. We think that the content and amount of cardioplegia and the preferred time for repeated cardioplegia applications are more important for the protection of the myocardium. Methods: 76 patients who did not have an acute myocardial infarction, had normal preoperative cardiac marker (troponin and CK-MB) values, did not undergo redo open heart surgery, had an ejection fraction of 50% and above, and underwent elective two or three-vessel isolated coronary artery bypass surgery were evaluated. While tepid(30-32 ° C) blood cardioplegia was administered antegrade to 33 patients(Group A) with a hand-squeezed bag, the other 34 patients(Group B) received tepid(30-32 °C) antegrade blood cardioplegia from the heart-lung machine. The perioperative and postoperative data of the patients were recorded and compared. To evaluate myocardial damage, postoperative cardiac markers and echocardiography data were evaluated and compared at the fourth hour after the cross-clamp was removed in both groups. Results: When evaluated in terms of preoperative demographic data, preoperative mean EF values and intraoperative data there was no statistical difference between both groups. When we evaluated in terms of myocardial protection, the mean TnT level was 4.31 ± 1.95 at the 4th hour in group A and 3.91 ± 1.69 in group B. Mean 4th hour CK-MB level was 40.84 ± 9.07 in group A and 38.56 ± 8.07 in group B. Mean change in EF (%) was -4.09 ± 4.41 in group A and 3.53 ± 4.53 in group B. In line with the current data when we evaluated in terms of myocardial protection; we found that there is no statistical difference between the two groups (p = 0.373; p = 0.158; p = 0.523). There was no statistical difference between both groups in terms of postoperative arrhythmia's. None of the patients died and none of the patients required an intra-aortic balloon pump.

Synthetic Material Abdominal Swabs Reduce Activation of Platelets and Leukocytes Compared to Cotton Materials

During surgical procedures, cotton abdominal swabs with their high absorptive capacity and malleability are used to retain organs and absorb blood or other body fluids. Such properties of the natural material cotton are advantageous for most operations, but in cardiopulmonary bypass (CPB) surgery, a high blood volume can accumulate in the thoracic cavity that is quickly retransfused via the heart–lung machine (HLM). This common practice is supposed to be safe due to the high anticoagulation. However, in vitro analyses showed that blood cells and plasma proteins were activated despite a high anticoagulation, which can propagate especially an inflammatory response in the patient. Thus, we investigated patients’ blood during CPB surgery for inflammatory and coagulation-associated activation after contact to the HLM and either cotton or synthetic abdominal swabs. Contact with cotton significantly increased thrombocyte and neutrophil activation measured as β-thromboglobulin and PMN-elastase secretion, respectively, compared to synthetic abdominal swabs. Both inflammatory cytokines, interleukin (IL) 1β and IL6, were also significantly increased in the cotton over the synthetic patient group, while SDF-1α was significantly lower in the synthetic group. Our data show for the first time that cotton materials can activate platelets and leukocytes despite a high anticoagulation and that this activation is lower with synthetic materials. This additional activation due to the material on top of the activation exerted by the tissue contact that blood is exposed to during CPB surgery can propagate further reactions in patients after surgery, which poses a risk for this already vulnerable patient group.

Coronary artery bypass grafting under sole Impella 5.0 support for patients with severely depressed left ventricular function

Selection of the ideal surgical procedure for coronary revascularization in patients with severe cardiac dysfunction at times may represent a challenge. In recent years, with the advent of surgical large microaxial pumps, e.g., Impella 5.0 (Abiomed Inc., Boston, USA), specific support and effective unloading of the left ventricle has become available. In the interventional field, good results have been achieved with smaller microaxial pumps in the setting of so-called protected percutaneous coronary intervention. In this study, we would like to share our early experience with surgical coronary revascularization under the sole support of Impella 5.0, omitting the use of heart–lung machine in three cases of severe cardiac dysfunction due to complex ischemic heart disease. Effective circulatory support intraoperatively and postoperatively speaks in favor of this technique in selected patients.

Central Aortic Cannula Disruption Following Left Atrial Myxoma Excision

Background Central aortic cannulation is used to give oxygenated blood to the patient through a heart-lung machine. Major surgical intraoperative bleeding during cardiac surgery is a dreaded complication, resulting in significant morbidity and mortality. Central Aortic cannula disruption during Cardiopulmonary bypass (CPB) is a rare complication which needs prompt management. Case Presentation We are reporting a case of central aortic cannula disruption during LA myxoma excision in which the Metal tip part of the cannula detached from its body, resulting in massive blood loss. Intraoperative blood salvage technique was used to maintain hemodynamics during surgery.Conclusion Aortic cannula disruption is a rare complication and can be lethal to the patient, if not managed timely. Before cannulation, proper visual inspection of all cannulae by team members is very important to eliminate this type of complication.

Fraction of expired oxygen: an additional safety approach to monitor oxygen delivery to the heart lung machine oxygenator

Background: Monitoring oxygen delivery to the oxygenator of a heart lung machine (HLM) is typically accomplished with an O2 analyzer connected to the gas inflow line. It is assumed when the FiO2 is greater than 21% that oxygen is being delivered to the oxygenator. However, this assumption is imperfect because the connection of the inflow line to the oxygenator is downstream from the O2 analyzer. FiO2 monitoring will not alert the perfusionist if the inflow line is not actually connected to the oxygenator. Measuring the fraction of expired oxygen (FEO2) is a more reliable way of monitoring O2 delivery. Methods: An O2 analyzer was placed on the scavenging line that is attached to the exhaust port of oxygenator (FEO2). Results: Whenever the FiO2 is greater than 21%, and the inflow line is properly connected, the FEO2 exiting the oxygenator is greater than 21%. The FEO2 falls to 21% when the inflow line is not functioning. Conclusion: Monitoring the FEO2 is a more reliable way to verify O2 delivery to an oxygenator. An alarm can be set on the FEO2 monitor to alert the perfusionist if the FEO2 falls below a predetermined threshold so any issue with O2 delivery will always be recognized.

Using a roller pump for establishing extra-corporal membrane oxygenation (ECMO) – technical considerations for times of crisis

Objective: The COVID-19 pandemic requires thinking about alternatives to establish ECMO when often-limited hardware resources are exhausted. Heart-lung-machines may potentially be used for ECMO but contain roller pumps as compared to centrifugal pumps in ECMO-circuits. We here tested roller pumps as rescue pump for ECMO-establishment. Methods: We set up in vitro circuits on roller pumps from C5 heart-lung-machine with 5 l/minutes flow. In two series, we placed either PVC or silicon tubing for an ECMO circuit into the roller pump. We assessed the mechanical stress on the tubing (aiming to run the pump for at least 1 week), measured the temperature increase generated by the friction and assessed flow characteristics and its measurement in simulated situations resembling tube kinking and suction. Results: The roller pumps led to expected and unexpected adverse events. PVC tubing burst between 36 and 78 hours, while silicon tubing lasted for at least 7 days. At 7 days, the silicone tubing showed significant signs of roller pump wear visible on the outside. The inside, however, was free of surface irregularities. Using these tubings in a roller pump led to a remarkable increase in circuit temperature (PVC: +12.0°C, silicone +2.9°C). Kinking or suction on the device caused the expected dramatic flow reduction (as assessed by direct measurement) while the roller pump display continued to show the preset flow. The roller pump is therefore not able to reliably determine the true flow rate. Conclusion: Roller pumps with silicone tubing but not PVC tubing may be used for running ECMO circuits. Silicone tubing may endure the roller pump shear forces for up to 1 week. Thus, repeated tubing repositioning may be a solution. Circuit heating and substantial limitations in flow detection should increase attention if clinical use in situations of crisis is considered.

Milestones in Understanding Pulmonary Circulation: From Antiquity to Heart-Lung Machine

Human pulmonary circulation is as full of mysteries and surprises as is the history of attempts to uncover and understand them. The Special Issue of Diagnostics, appearing after 2020 immobilized the world, give us an opportunity, space and momentum to remind to our medical community at least the main milestones which mark the progress that was made before our times. This review’s aim is to remind about pioneers and their ideas which now are considered as if they were always with us—which is not the case…