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Standards and guidelines for cardiopulmonary bypass have been established by various professional societies. They serve as an instrument to guide safe and effective patient care. We conducted a survey of practicing perfusionists in Kenya to learn about their background, education, current clinical practice and about their knowledge, and attitude regarding standards and guidelines. Two multiple-choice surveys were distributed to all known practicing perfusionist in Kenya using SurveyMonkey (San Mateo, CA). Multiple-choice questions related to professional background, training, annual procedure volume, staffing models, clinical practices, the use of safety devices, and the use of checklists were included in the questionnaires. The survey also inquired about familiarity with American and European perfusion practice standards and guidelines and opinions on establishing standards in Kenya. Responses were received from 12 perfusionists practicing at 10 centers. Professional backgrounds included anesthesia nursing, clinical officers, and critical care nursing. Sixty-seven percent (8/12) received formal training and 33% (4/12) trained primarily through clinical instruction. Of those that received formal training, 63% (5/8) received 1-2 years of training, 25% (2/8) <1 year but more than 6 months, and 12.5% (1/8) received 6 months of formal training. The median clinical experience was 5 years (range 1-22). The median annual case load was 54 (range 0-100). Use of safety devices was reported as follows: level sensor 75% (9/12), air bubble detector 17% (2/12), one-way vent valves 67% (8/12), continuous venous oxygen saturation monitoring 25% (3/12), and gas supply analyzers 33% (4/12). More than one-third of the respondents had no knowledge of the American and European perfusion practice standards, and nearly two-thirds were aware of or had read them. This survey provides contextual information about perfusion practice in Kenya in 2021. There was consensus among perfusionists to develop standards and practice guidelines for Kenya., (© Copyright 2022 AMSECT.)

New cardiopulmonary bypass device techniques emerge and are reported in the scientific literature. The extent to which they are actually adopted into clinical practice is not well known. Since 1989, we have periodically surveyed pediatric cardiac centers to ascertain practice patterns. In December 2016, a 186-question perfusion survey was distributed to pediatric cardiac surgery centers all over the world using a Web-based survey tool. Responses were received from 93 North American (NA) centers (the United States and Canada) and 67 non-NA (NNA) centers, representing 19,645 cumulative annual procedures in NA and 27,776 in NNA centers on patients <18 years. Wide variation in practice was evident across geographic regions. However, the most common pediatric circuit consisted of a hard-shell (open) venous reservoir, an arterial roller pump, and a hollow-fiber membrane oxygenator with a separate or integrated arterial filter. Compared with our previous surveys, there was increased utilization of all types of safety devices. The use of an electronic perfusion record was reported by 50% of NA centers and 31% of NNA centers. There was wide regional variation in cardioplegia delivery systems and cardioplegia solutions. Seventy-nine percent of the centers reported the use of some form of modified ultrafiltration. The survey demonstrated that there remains variation in perfusion practice for pediatric patients. Future surveys will be useful to evaluate the adoption of emerging perfusion practice guidelines., (© Copyright 2021 AMSECT.)

Modified ultrafiltration (MUF) is a novel application of ultrafiltration to remove excess water after cardiopulmonary bypass in pediatric patients that was first reported in 1991. It has gained widespread use as an important adjunct to fluid management in neonates, infants, and pediatric cardiac surgery patients. Now more than two decades after its original description, the exact mechanism of action and effects of this therapy are still a matter of discussion. The aim of this study was to determine the effects of MUF on plasma fentanyl levels using a two-phase in vitro and in vivo study. We designed an in vitro experimental model to simulate MUF that allowed measurement of plasma fentanyl levels while eliminating biologic variables. Plasma fentanyl levels were measured during five consecutive operations on neonates and infants undergoing repair of congenital heart defects. Increases in plasma fentanyl levels were found in vitro as well as in vivo. Fentanyl plasma levels more than doubled after MUF (increased by a factor of 2.22, from 12.4 to 27.5 ng/ml in vivo). The increase in plasma fentanyl levels needs to be taken into account when delivering anesthetic care and when analyzing the effect of MUF on outcome variables.

Introduction: A portion of patients undergoing cardiac surgery may develop focal and/or subtle brain injuries secondary to cardiac surgery. There is evidence that, in some cases, these injuries may be related to cardiopulmonary bypass (CPB). Embolism and hypoperfusion are the dominant mechanisms for focal neurologic injuries among coronary artery bypass graft (CABG) surgery patients. Recent studies suggest that these mechanisms may also produce the more prevalent subtle neurological deficits. The aim of our current work is to obtain a thorough understanding of the processes of care associated with the production of embolic activity, cerebral hypoperfusion, and hemodynamic aberrations that often occur during CPB., Methods: We developed a system for simultaneous recording of physiologic parameters, embolic activity in the CPB circuit and in the cerebral arteries, and near infrared regional cerebral oxyhemoglobin saturation (NIRS) during cardiac surgery. All data were synchronized with a video recording of the surgical procedure. Periods of embolic activity and NIRS were subsequently related to surgical and CPB processes of care through a systematic review of the patient's surgical case video., Results: To date, we have enrolled 47 patients undergoing coronary and/or valvular procedures. We have observed wide variation across patients in detected cerebral embolic counts, NIRS and physiologic parameters. We have identified increased embolic counts in the CPB circuit related to specific processes and events such as the method of venous drainage, the entrainment of air in the venous line, the injection of medications into the CPB circuit and blood sampling from the CPB circuit. A portion of detected changes in NIRS were related to periods of hypotension and positioning of the heart during the construction of distal coronary artery grafts on the posterior coronary artery vessels., Summary: Use of this model provides the surgical team with detailed information regarding the contribution of CPB to the creation of precursors of neurological injury. This system provides meaningful data to guide the surgical team in the redesign of the CPB system and associated techniques.

We present here a technique to replace a failed oxygenator by inserting a second oxygenator in parallel (PRONTO) within the cardiopulmonary bypass (CPB) circuit. Oxygenator failure is a potential hazard that may result in patient injury or death. Although failures are rare, safety surveys conducted over the last 25 years suggest that the incidence of oxygenator failures is on the rise. This emergency procedure may be easily applied to any standard CPB circuit with a few minor alterations. The technique is simple; it can be carried out rapidly. An important advantage of this technique is that it may be executed without interrupting blood flow to the patient, which may reduce the incidence of patient injury or death.

Low hematocrit (Hct < 20) during cardiopulmonary bypass (CPB) is associated with higher mortality and other adverse outcomes. More frequently, low Hct is encountered in patients with small body size and women patients. This prompted us to take an aggressive approach in our care of these patients, involving a strategy for predicting patients at risk of low Hct, with the aid of an electronic worksheet that accurately predicts CPB Hct, and two prevention strategies: use of a low-prime CPB circuit (LP) for all adult patients with a body surface area (BSA) < 1.7 m(2) and use of autologous circuit priming (AP), in addition to the low-circuit volume in some patients. The two cohorts of patients in whom these techniques were employed were compared to a group matched for body size where our standard adult circuit (STD) was used. There were 233 patients in the standard group, 139 in the LP group, and 68 in the LP/AP group. The CPB circuit prime volume was 1,710 ml for the STD group and 1,110 ml for the LP group. Use of autologous priming techniques further reduced the prime volume by 545 +/- 139 ml. The incidence of low Hct (<20%) during CPB was thus reduced from 70% to 15% (p = 0.001) when using both techniques together without increasing red blood cell (RBC) transfusions. These changes in perfusion management resulted in a reduction in the incidence of renal complications (STD = 9.4%, LP = 6.5% (ns) and LP/AP = 0%,

Devices and techniques used for pediatric cardiopulmonary bypass are ever changing. There are frequently reports in the literature about new techniques and new devices. Periodic surveys are helpful because they reveal the actual extent to which these techniques and devices are applied to clinical practice. Advances in research are bringing about a better understanding of the intricate aspects of CPB and the effects of CPB on pediatric patients. There appears to be a trend from widely divergent approaches to CPB for pediatric patients to more uniformity in practice. For example, the use of membrane oxygenation and arterial line filtration has become universal, and there is an increase in the use of all types of safety devices. Techniques reported in the medical literature at the beginning of the decade, such as, the use of modified ultrafiltration, the use of centrifugal cell washers to process packed red blood cells before adding them to the prime, and the use of the antifibrinolytic drug, aprotinin, have become part of practice at a large number of pediatric heart centers. Periodic surveys are useful, as they provide a measurement of current practice. They also provide a historical record of the advances in the field.

A revised circuit design for modified ultrafiltration is presented rendering the technique more convenient for use after cardiopulmonary bypass when blood cardioplegia is used. The procedure employs a hollow-fiber ultrafiltration device attached to the cardioplegia circuit. A bubble trap, heat exchanger, and a pressure monitor are incorporated as safety features. The technique has been used in 80 patients (30 pediatric and 50 adult) and has been associated with relevant increases in colloid osmotic pressure and hematocrit.

The development of a large animal preparation using 31P nuclear magnetic resonance (NMR) spectroscopy for the study of cerebral and myocardial metabolism during cardiopulmonary bypass (CPB) is reported. The effect of normothermic CPB on myocardial and cerebral metabolism was evaluated. Adolescent sheep were used which have low levels of 2,3-diphosphoglycerate, a compound which can interfere with the calculation of intracellular pH and inorganic phosphate content. CPB was performed using standard procedures modified for the presence of a high magnetic field and limited access to the animal. High quality 31P NMR data were obtained from the brains and hearts of these animals before and during normothermic CPB. These results demonstrate that the initiation of normothermic CPB does not change high energy phosphate levels or intracellular pH. In particular, the decreased myocardial oxygen demand associated with CPB is not associated with improvement in the levels of adenosine triphosphate or phosphocreatine. The measurements of energy metabolism and intracellular pH of the brain and heart during CPB were possible within the constraints of the NMR experiment without compromising the CPB procedure. Combining NMR and CPB techniques permits future studies of cerebral and myocardial metabolism, especially those relating to ischemia.