bluuebunny/crossref_metadata_2025 huggingface dataset:
Clinical Evaluation of Poly(2-methoxyethylacrylate) in Primary Coronary Artery Bypass Grafting
Authors: Vang See N. , Brady Chad P. , Christensen Kevin A. , Isler Jack R. , Allen Keith R.
Published: July 2023

In an attempt to make cardiopulmonary bypass (CPB) less traumatic for patients undergoing cardiac surgery, extracorporeal circuits (ECC) have been modified to achieve this goal. Poly(2-methoxyethylacrylate) (PMEA, X-coating™) is a new polymer coating used in the ECC. PMEA studies have shown excellent biocompatibility with the components of blood. In this evaluation, PMEA-coated ECC were compared with control (CTR) circuits with emphasis on hematological parameters, perioperative homologous blood product usage, and clinical outcomes. Patients undergoing elective coronary artery bypass grafting were randomized to either a PMEA group (n= 30) or a CTR group (n= 30). Extracorporeal circuit components in the PMEA group were coated except for the cardioplegia delivery device and cannulas. Patients in the CTR group had just the arterial line filter coated. The following hematological parameters were measured: platelet count (PLT), white blood cell count (WBC), red blood cell count (RBC), and hematocrit (Hct). Blood product usage was observed along with clinical outcomes for the following parameters: ventilation time, mediastinal tube output, intensive care unit (ICU) and hospital lengths of stay. The preoperative patient profiles were comparable between the two groups. The PMEA group had marginally higher CPB times (134 ± 31.9 vs. 118 ± 33.7 minutes) and cross clamp times (83.9 ± 21.3 vs. 73.7 ± 21.6 minutes), however no significant differences were reached. Platelet count, RBC, and Hct levels were also comparable between groups with no significant differences. However, there was a significant difference in WBC between groups (p= 0.041). Less platelets were administered both intraoperatively and 48 hours postoperatively in the PMEA group. The authors evaluated PMEA-coating by measuring clinical outcomes, such as ventilation time, ICU and hospital lengths of stay, and homologous blood utilization. PMEA patients trended towards less homologous blood transfusions, which helped save an average of $83.41 per patient. Further clinical studies are needed to evaluate the benefits of this new polymer coating.
Can Lean Body Mass Be Used to Reduce the Dose of Heparin and Protamine for Obese Patients Undergoing Cardiopulmonary Bypass?
Authors: Baker Mya S. , Skoyles Julian R. , Shajar Matt , Skinner Henry , Richens David , Mitchell Ian M.
Published: July 2023

Increasing numbers of obese patients are presenting for cardiac surgery. The convention for heparin dose dictates that a bolus of 300 IU heparin per kilogram of total body weight (TBW) is administered before CPB. During CPB, the activated clotting time (ACT) is maintained for longer than 480 seconds. At the end of the procedure, protamine is administered to neutralize heparin and achieve hemostasis. Both of these drugs can have serious side effects: heparin can induce thrombocytopenia, and protamine has been known to cause reactions in patients allergic to fish, vasectomized men, and some patients with insulin-dependent diabetes. The calculation of lean body mass (LBM) may be a more accurate method of determining drug doses as opposed to TBW and may avoid giving obese patients a relative overdose of heparin, which must subsequently be neutralized with protamine. LBM can be determined by different methods. This study used bio-electrical impedance analysis as a simple, quick, and accurate method of calculating LBM. A comparison was made between two groups of patients whose body mass index (BMI) was >27 kg/m2: Group 1,n_ 13, mean BMI _ 32, mean body fat _ 36% received the conventional dose of 300 IU/kg heparin for their TBW. Group 2,n_ 14, mean BMI _ 31, mean body fat _ 35% received a dose of 300 IU/kg heparin for their calculated LBM. ACT was conducted before and after heparin administration. Additional heparin was administered as required to achieve target ACT > 400 s. Mean ACT results and total heparin doses were analyzed using unpaired two tailedttests. Our results indicate that with care, a reduction of as much as 25% in the doses of heparin (p_0.0001) and protamine can be achieved for a substantial number of patients classified as overweight or obese.
General Anesthesia in Cardiac Surgery: A Review of Drugs and Practices
Authors: Alwardt Cory M. , Redford Daniel , Larson Douglas F.
Published: July 2023

General anesthesia is defined as complete anesthesia affecting the entire body with loss of consciousness, analgesia, amnesia, and muscle relaxation. There is a wide spectrum of agents able to partially or completely induce general anesthesia. Presently, there is not a single universally accepted technique for anesthetic management during cardiac surgery. Instead, the drugs and combinations of drugs used are derived from the pathophysiologic state of the patient and individual preference and experience of the anesthesiologist. According to the definition of general anesthesia, current practices consist of four main components: hypnosis, analgesia, amnesia, and muscle relaxation. Although many of the agents highlighted in this review are capable of producing more than one of these effects, it is logical that drugs producing these effects are given in combination to achieve the most beneficial effect. This review features a discussion of currently used anesthetic drugs and clinical practices of general anesthesia during cardiac surgery. The information in this particular review is derived from textbooks, current literature, and personal experience, and is designed as a general overview of anesthesia during cardiac surgery.
The Effect of Temperature and Aprotinin During Cardiopulmonary Bypass on Three Different Methods of Activated Clotting Time Measurement
Authors: Machin David , Devine Philip
Published: July 2023

The activated clotting time (ACT) is used frequently for monitoring blood anticoagulant response with heparin before, during, and after cardiopulmonary bypass (CPB). Many cardiac procedures involving CPB require reduction of the patient’s blood temperature and use of the serine protease inhibitor, aprotinin. Three different methods of ACT measurement were compared to show the effects of different CPB temperatures and the presence of aprotinin. A total of 42 patients were included in the study: 14 received CPB at 28°C, 14 received CPB at 32°C, and 14 normothermic (37°C) CPB. Within each temperature group, seven received aprotinin. The ACT in each group of patients was measured by a celite activator (C-ACT), a kaolin activator (K-ACT), and a celite, kaolin and glass activator (MAX-ACT). All three methods of ACT measurement showed significant increases (p< .05) in clotting times at hypothermic CPB compared with normothermic groups. During heparinization the C-ACT was significantly increased (p< .05) in the presence of aprotinin. Comparability between the 3 ACT measurement methods showed a very high correlation between C-ACT and K-ACT clotting times (R2= .8962), and slightly lower correlation between MAX-ACT and C-ACT (R2= .7780), and MAX-ACT and K-ACT (R2= .7827). All ACT measurements are affected by changes in blood temperature. The C-ACT measurement is prolonged with aprotinin, whereas the MAX-ACT and K-ACT method of measurement in the presence of aprotinin are not significantly altered. It appears that the MAX-ACT produces lower values and may necessitate additional heparin therapy for ACT target values considered safe during CPB. Further study is required from these additional findings.
Sensitivity of a Modified ACT Test to Levels of Bivalirudin Used During Cardiac Surgery
Authors: Zucker Marcia L. , Koster Andreas , Prats Jayne , LaDuca Frank M.
Published: July 2023

Assessment of anticoagulation status during cardiac surgery can be valuable for novel therapeutics, including direct thrombin inhibitors. The ecarin clotting time (ECT) has been reported to be sensitive for monitoring of bivalirudin in cardiac surgery but is not commercially available. The activated clotting time (ACT), commonly used for heparin monitoring, may display a lack of sensitivity to alternative anticoagulants when used in on-pump cardiac surgery. Both the ACT and ECT have been successfully used for monitoring bivalirudin anticoagulation in off-pump cardiac surgery. A new ACT, the ACTT, was developed to increase the linearity of the clotting time response to bivalirudin at higher concentrations. After Ethics Committee approval, a pilot study was performed to evaluate the feasibility of using bivalirudin for on-pump cardiac surgery and to evaluate dosing of bivalirudin in terms of the pharmacokinetic and safety profile in patients undergoing coronary artery bypass graft (CABG) surgery. Secondary objectives included an assessment of the anticoagulation profile and correlation of the response seen with various ACTs and the ECT with the plasma bivalirudin concentration in the patients’ blood. After informed consent, 10 sequential patients presenting for elective cardiac surgery requiring cardiopulmonary bypass received bivalirudin anticoagulation in lieu of heparin. Dosing was fixed (1.0 mg/kg bolus followed by a 2.5 mg/kg/h infusion) and not titrated on the basis of coagulation test results. At baseline and 15-minute intervals, blood samples were collected for ACT (ACTT, Celite, kaolin, ACT+), ECT, and bivalirudin plasma level measurements. Over the range of bivalirudin plasma concentrations in this study, all clot-based systems examined were prolonged according to concentration and showed good correlation with bivalirudin plasma levels. The ACTT and the ECT showed greater sensitivity to bivalirudin (∼28.5 sec/μg/ml bivalirudin) compared with the other ACTs evaluated (∼14 sec/μg/ml). This difference in sensitivity was also evident at low concentrations of bivalirudin (<10 μg/ml), with the ECT and ACTT showing slopes near 40, and the ACT slopes varying from 18 to 27 sec/μg/ml. The ACTT assay is sensitive to levels of bivalirudin and may offer a simple method for monitoring bivalirudin during cardiac surgery.
Use of the CDI Blood Parameter Monitoring System 500 for Continuous Blood Gas Measurement During Extracorporeal Membrane Oxygenation Simulation
Authors: Schreur Aaron , Niles Scott , Ploessl James
Published: July 2023

The Oximetrix III Opticath (Abbott Critical Care Systems) is used for continuous measurement of venous saturation in a variety of applications, including extracorporeal membrane oxygenation (ECMO), despite clinical reports that have presented data showing poor accuracy of these devices. The CDI Blood Parameter Monitoring System 500 (Terumo) is an inline blood gas monitoring tool commonly used during cardiopulmonary bypass procedures to continuously assess oxygen saturation, blood gases, potassium, and bicarbonate. The purpose of this experiment was to compare the Opticath and the CDI 500 in trending venous blood saturation during a simulation of ECMO. An ECMO simulation circuit consisting of a silicone rubber membrane oxygenator and a stainless steel heat exchanger was constructed, and a standard venous reservoir bag was used to represent the patient. The CDI and the Opticath were incorporated side by side into a shunt that originated just before the oxygenator and returned flow to the venous line. The circuit was primed with fresh porcine blood and conditioned with the addition of CO2to simulate typical venous blood under ECMO conditions. After an initial calibration procedure, samples were drawn and analyzed by an AVL Opti CCA (Roche/Osmetech) every 4–8 hours for a period of 7 days, with calibration of each device at sample intervals. The data were plotted, and a least squares regression line was calculated. The average error for venous saturation of the CDI and Opticath after 72 hours was 3.86 and 9.51 respectively. At 168 hours, error for the CDI was 8.37, and the Opticath had an error of 14.78. A correlation analysis of the CDI and AVL CCA analyzer yielded a correlation coefficient ofr= .88 at 72 hours andr= .84 at 168 hours. Correlation between the Opticath and the AVL CCA yielded a correlation coefficient ofr= .77 at 72 hours andr= .55 at 168 hours. Based on these findings, the CDI 500 is an effective tool for monitoring venous blood saturation under simulated conditions of ECMO.
Second Generation of Minimal Invasive Extracorporeal Circuit: Pilot Study Resting Heart System
Authors: Fayad George , Modine Thomas , Naja Ghassan , Larrue Benoit , Azzaoui Richard , Crépin Francis , Decoene Christophe , Benhamed Lots , Koussa Mohamed , Gourlay Terence , Warembourg Henry
Published: July 2023

Cardiopulmonary bypass (CPB) has evolved from a complex multifunctional system to the minimally invasive extra-corporeal circuit (MIEC). Concerns currently exist regarding the technically demanding nature of off-pump coronary artery bypass (OPCAB) procedures, the quality of anastomosis associated with it, and the difficulty in achieving “complete revascularization.” Recognizing these issues, the so-called mini-CPB concept has evolved in an effort to offer the perceived benefits of OPCAB with the technical advantages of CPB and at the same time minimize the adverse effects of full-scale CPB. The first generation of MIEC had an inherited risk of gas embolisms. Therefore, there was the introduction of the resting heart system (RHS), the main characteristic of which is the venous air removal device. The aim of this study was to describe our early experience, feasibility, and safety with this system to help others who are considering introducing this technique into their clinical practice. Using this system, we operated on 30 consecutive patients. Moderate hypothermia (33°C) CPB and cold intermittent antegrade cardioplegia was used. No technical incidents were encountered. One death from multiorgan failure occurred in a patient operated on for a thoraco-abdominal aneurysm. Our own short-term experience with the RHS has been very favorable, and we will continue to explore this development in CPB technology.
Clinical Evaluation of the ABL-77 for Point-of-Care Analysis in the Cardiovascular Operating Room
Authors: Prichard Jack S. , French John S. , Alvar Nestor
Published: July 2023

As a small portable instrument, which can be dedicated to the perfusionist, the Radiometer model ABL-77 point-of-care blood gas, electrolyte, and hematocrit analyzer has come to provide an alternative to in-line monitoring of such parameters. This is not to say that it can necessarily replace the utility of in-line monitoring. However, point of care instruments, such as the ABL-77, can provide faster results than a more remote lab. This study was done as part of an ongoing quality assurance program in conjunction with the main lab department to maintain accreditation. The hypothesis being tested is that during cardiopulmonary bypass (CPB) the ABL-77 is in agreement with alternative instruments used outside the cardiovascular operating room. With the appropriate institutional approval, a total of 20 blood samples were randomly gathered among five patients after initiation of CPB. This was done over a five-day period for pH, pCO2, pO2, potassium, sodium, and hematocrit determinations. Analysis results from the ABL-77 were compared to those made by three other bench top models. These included a Radiometer model ABL-720 analyzer, a Dale Dimension model RxL analyzer, and a Beckerman model LH 750 Coulter Counter. A statistically significant difference is demonstrated for all parameters when each of these instruments is compared to the ABL-77. However, the observed mean differences are only judged to be clinically significant in the case of hematocrit. The ABL-77 is found to demonstrate a negative bias with respect to the different methodologies used by the ABL-720 and the Coulter Counter. This bias may be due to the hemodilution of plasma with crystalloid solution during CPB. This causes error in hematocrit results as the methodology of many point of care instruments is based on the electrical conductivity of whole blood. This may be corrected by using a relationship determined from linear regression analysis. This error adjustment has been implemented as part of a concerted blood conservation effort. Otherwise, the ABL-77 has been found to be reliable and consistent for point of care blood analysis.
Effects of Conventional Ultrafiltration on Renal Performance During Adult Cardiopulmonary Bypass Procedures
Authors: Kuntz Rick A. , Holt David W. , Turner Scott , Stichka Lee , Thacker Bryan
Published: July 2023

Ultrafiltration has been used successfully in a variety of applications in the perioperative setting to assist in hemoconcentration and volume reduction. This study was designed to investigate the effects of aggressive conventional hemofiltration on bypass urine production, fluid balance, and renal performance in the 24 hours after bypass procedures in the adult population. A prospective, randomized study was designed to determine the effects of conventional ultrafiltration (CUF) during bypass while monitoring urine dynamics intraoperatively and in the 24-hour post-bypass period. Study group 1 (CUF,n= 49) was compared to control group 2 (non-CUF,n_ 47) by monitoring urine values, volume additions, and packed red cell (PRC) use throughout the procedure. The mean total CUF volume removed from group 1 was 5781 ± 2612. There were no differences in prebypass, total bypass, or total operating room (OR) urine between the two groups. The 24-hour urine totals were significantly higher in group 2 (2389 ± 895) than in group 1 (2035 ± 895). The ending bypass hematocrit was also lower in group 2 (26 ± 2.0) than in group 1 (30 ± 6.0). OR PRC additions were higher in group 2 (395 ± 699) than group 1 (204 ± 300). The non-CUF control group 2 experienced significantly greater ending fluid balance (3006 ± 868) compared with group 1 (744 ± 1271). No significant differences in pre- or postoperative creatinine values were observed. Aggressive CUF can be safely used during cardiopulmonary bypass in the adult population to reduce fluid accumulation and elevate bypass hematocrit without effecting bypass or intraoperative urine production.
Platelet-Rich Plasma and Platelet Gel: A Review
Authors: Everts Peter A.M. , Knape Johannes T.A. , Weibrich Gernot , Schönberger Jacques P.A.M. , Hoffmann Johannes , Overdevest Eddy P. , Box Henk A.M. , van Zundert André
Published: July 2023

Strategies to reduce blood loss and transfusion of allogeneic blood products during surgical procedures are important in modern times. The most important and well-known autologous techniques are preoperative autologous predonation, hemodilution, perioperative red cell salvage, postoperative wound blood autotransfusion, and pharmacologic modulation of the hemostatic process. At present, new developments in the preparation of preoperative autologous blood component therapy by whole blood platelet-rich plasma (PRP) and platelet-poor plasma (PPP) sequestration have evolved. This technique has been proven to reduce the number of allogeneic blood transfusions during open heart surgery and orthopedic operations. Moreover, platelet gel and fibrin sealant derived from PRP and PPP mixed with thrombin, respectively, can be exogenously applied to tissues to promote wound healing, bone growth, and tissue sealing. However, to our disappointment, not many well-designed scientific studies are available, and many anecdotic stories exist, whereas questions remain to be answered. We therefore decided to study perioperative blood management in more detail with emphasis on the application and production of autologous platelet gel and the use of fibrin sealant. This review addresses a large variety of aspects relevant to platelets, platelet-rich plasma, and the application of platelet gel. In addition, an overview of recent animal and human studies is presented.
In Vitro Evaluation of the Air Separation Ability of Four Cardiovascular Manufacturer Extracorporeal Circuit Designs
Authors: Dickinson Timothy A. , Riley Jeffrey B. , Crowley Jeffrey C. , Zabetakis Paul M.
Published: July 2023

Neurologic impairment is a common complication of adult cardiac surgery. Cerebral gaseous microemboli (GME) detected during cardiopulmonary bypass has been associated with cognitive impairment after adult cardiac surgery. Several previous studies have shown that components comprising the extra-corporeal circuit (ECC) can affect the ability of the ECC to eliminate air. The differences in the air separation ability of four manufacturer’s commonly used ECCs were studied. The air-separating ability of Cobe Cardiovascular, Gish Biomedical, Medtronic, and Terumo Cardiovascular Systems Corp. ECCs were studied in vitro under clinically relevant conditions. Bolus and continuous venous air were introduced and output GME patterns by size, time, and count were measured (using an embolus detection device) and statistically analyzed. Graphic representations depicting elapsed time, GME size, and bubble count helped to visually rank the air-handling performance of the ECCs. There are significant air-handling differences between the ECCs tested. Overall, the blinded results reveal that ECC A and ECC C removed significantly (p< 0.001) more suspended GME than ECC B and ECC D. In the 50-mL venous room-air bolus and the 100 mL/min pulsed air challenges, ECC B and ECC D allowed significantly more GME to pass (p< 0.001) compared with ECC A and ECC C. For example, in a 2-hour pump run ECC C would deliver 480 potential high-intensity transient signals (HITS) compared with the 9600 from the ECC B during venous room air entrainment at 100 mL/min. There are substantial and significant air-handling differences between the ECCs from the four different manufacturers. The results from this work allow for objective characterization of ECCs air-separating ability. This additional information provides an opportunity for clinicians to potentially minimize the risks of arterial air embolization and its associated deleterious neurologic effects, while allowing clinicians to make better-informed consumer decisions.
Australian and New Zealand Perfusion Survey: Equipment and Monitoring
Authors: Baker Robert A. , Willcox Timothy W.
Published: July 2023

The current practice of perfusion in Australia and New Zealand continues to adopt new techniques and procedures into clinical practice. Our aims were to report current practice in 2003 and to compare and contrast current practice with historic practice. A total of 62 centers (40 perfusion groups) performing procedures using cardiopulmonary bypass (CPB) were identified and were e-mailed a detailed electronic survey. The survey was comprised of an excel worksheet that contained 233 single answer questions (either dropdown lists, yes/no, true/false, or numeric) and 12 questions that allowed the respondent to provide a commentary. Respondents were instructed to answer all questions based on what represented the predominant practice of perfusion in their institutions during 2003. We report an 89% response rate representing a caseload of 20,688 adult cases. These data allowed us to profile the following. A standard adult CPB setup in 2003 consisted of a membrane oxygenator (100% of cases), a roller pump (70%) as the main arterial pump, although a centrifugal pump would be considered for selected procedures (30%), a circuit incorporating a hard-shell venous reservoir (86%), and a mixture of biocompatible and nonbiocompatible circuit components (66%). The circuit would include a pre-bypass filter (88%), an arterial line filter (94%), and would allow monitoring of the following: hard-shell venous reservoir low level (100%) with servo-regulation of the arterial pump (85%), microbubble alarm (94%) with servo-regulation of the arterial pump (79.5%), arterial line pressures (100%) with servo-regulation of the arterial pump (79%), inline venous O2saturation (100%), and inline hematocrit (58%). Perfusion practice in Australia and New Zealand has adopted changes over the last decade; however, some areas of practice show wide variation. This survey provides a baseline of contemporary practice for Australian and New Zealand perfusionists.
Quantitative and Qualitative Analysis of Platelet-Rich Plasma Collection Using the Haemonetics Cell Saver 5 in Open Heart Surgery
Authors: Fried David W. , Leo Joseph J. , Weber Frederick P. , Husain Mansoor , Cullen James
Published: July 2023

Many traditional autologous blood recovery systems (ABRSs) have undergone modifications to enable them to collect platelet-rich plasma (PRP). Because of the growing demand for autologous platelet gel (APG) in cardiac surgery, many open heart teams are faced with the choice of using their existing ABRS or purchasing a dedicated PRP device. This study was conducted to address the issues we had about our use of the Haemonetics Cell Saver 5 (CS5) to collect PRP during open heart surgery at our institution. PRP and platelet-poor plasma (PPP) were collected on 20 “first-time” elective open heart surgical patients. Baseline, PRP, and PPP platelet counts, as well as modified thrombelastograms (TEGs), were performed on all study patients. The mean baseline, PRP, and PPP platelet counts were 232,450, 1,348,850, and 18,100/mm3, respectively. We found a strong positive correlation (r= +0.7142) between the maximum amplitude (MA) of our modified PRP TEG and the platelet count of the PRP. Using the CS5, we achieved a mean platelet multiple of greater than six times baseline, which compares favorably with the multiple produced using dedicated PRP devices. These data support the conclusion that we achieved a high platelet multiple with the CS5, and our use of a modified TEG showed that platelet function of the collected PRP was preserved.
Platelet-Rich Plasma Combined With Skin Substitute for Chronic Wound Healing: A Case Report
Authors: Knox Rebecca L. , Hunt Allen R. , Collins John C. , DeSmet Marie , Barnes Sara
Published: July 2023

Contemporary management of chronic wounds focuses on improving natural healing and individualization of treatment. Incorporating multiple therapies has become increasingly common. Of interest are autologous growth factors, which are especially important in chronic wound healing and may contribute to tissue formation and epithelialization. Autologous platelet concentrate or platelet-rich plasma (PRP) is a concentration of at least five autologous growth factors and has been shown to accelerate wound healing and may have infection-fighting properties. Chronic wound healing is complicated by both decreased growth factor availability and infection, making PRP use valuable in these types of wounds. In this report, the use of PRP therapy alone and in combination with a bioengineered skin substitute as a platelet-rich tissue graft in a chronic, non-healing wound is detailed. Over 27 weeks, the patient received multiple therapies in attempts to heal a severe decubitus ulcer of the sacrum. The introduction of PRP therapy at Week 14 led to a 26% reduction in wound depth over 4 weeks. At Week 19, PRP therapy was combined with a powdered skin substitute to create a platelet-rich tissue graft. The combination brought dramatic results, eliminating wound tunneling and reducing the wound dimensions from 6.2 cm long × 6.7 cm wide × 2.7 cm deep to 5.0 cm long × 6.0 cm wide × 1.4 cm deep. The promising observations from this case report indicate that further study on the combining of PRP therapy and skin substitutes is necessary.
Perfusion Techniques for Pulmonary Thromboendarterectomy Under Deep Hypothermia Circulatory Arrest: A Case Series
Authors: Ji Bingyang , Liu Jinping , Wu Yongbo , Wang Guyan , Feng Zhengyi , Liu Mingzheng , Long Cun , Song Yunhu
Published: July 2023

Pulmonary thromboendarterectomy (PTE) is a complicated surgical procedure that is an effective treatment in reducing pulmonary artery pressure and pulmonary vascular resistance for chronic thromboembolic pulmonary hypertension. Chronic thromboembolic pulmonary hypertension usually results from incomplete lysis of a large organized thrombus in the main pulmonary artery and secondary branches, leading to pulmonary hypertension, right ventricular failure, and subsequent death because of heart failure. Between March 1997 and April 2005, 30 PTE operations were performed in Fuwai Hospital, Beijing, China. They were 24 men and 6 women, with an average age of 45.7 ± 11.4 years and average disease history of 48 ± 12.6 months. Twelve of them were in New York Heart Association (NYHA) class 4, and 18 were in class 3. Seventeen cases were found with deep venous thrombosis (DVT), and inferior vena cava filters were implanted before surgery. The mean systolic pulmonary pressure was 91.4 ± 22.4 mmHg, mean pressure of arterial oxygen (PaO2) was 56.2 ± 8.6 mmHg, mean cardiac index (CI) was 1.64 ± 0.47 L/min/m2, and mean saturation of arterial oxygen (SaO2) was 0.90 ± 0.05. All operations were performed using the PTE procedure under deep hypothermia and intermittent circulation arrest. Perfusion management consisted of myocardial, cerebral protection, lung protection, and deep hypothermia with multiple periods of circulatory arrest and reperfusion at hypothermia, ultrafiltration, and cell-saving techniques. One patient died of infective shock post-operatively. Four cases experienced complications of the central nervous system. The mean cardiopulmonary bypass time was 191.1 ± 34.4 minutes, the mean aortic clamping time was 95.1 ± 27.8 minutes, and mean circulation arrest time was 47.7 ± 12.9 minutes. Improvement of hemodynamic status occurred immediately after surgery. Mean pulmonary artery pressure decreased from 91.4 ± 22.4 to 48.3 ± 10.7 mmHg, and CI increased from 1.64 ± 0.47 to 2.58 ± 0.51 L/min/m2. PaO2 increased from 56.2 ± 8.6 to 88.9 ± 6.0 mmHg and SaO2 increased from 0.90 ± 0.05 to 0.97 ± 0.01. Twenty-six cases were followed for 36.8 months: 22 in NYHA class 1, 3 in class 2, and 1 in class 3. PTE is an effective treatment for chronic thromboembolic pulmonary hypertension. The key to success is to adopt synthesized measures to protect the vital organ under deep hypothermic circulatory arrest (DHCA) from ischemia and reperfusion injury. Appropriate patient selection, perioperative management, improved techniques, and experience can optimize outcome.
Heparin Sensitivity Test for Patients Requiring Cardiopulmonary Bypass
Authors: DeBois William J. , Liu Junli , Elmer Barbara , Ebrahimi Haleh , Voevidko Lilia , Lee Leonard Y. , Krieger Karl H. , Isom Wayne W. , Girardi Leonard N.
Published: July 2023

Anticoagulation for the open heart surgery patient undergoing cardiopulmonary bypass (CPB) is achieved with the use of heparin. The industry standard of activated clotting time (ACT) was used to measure the effect of heparin. The commonly acceptable target time of anticoagulation adequacy is 480 seconds or greater. Some patients, however, exhibit resistance to standard dosing of heparin and do not reach target anticoagulation time (480 seconds). Antithrombin III deficiency has been previously cited as the cause of heparin resistance. Early detection of heparin resistance (HR) may avoid both the delayed start of CPB and inadequate anticoagulation, if emergency bypass is required. An anticoagulation sensitivity test (AST) was developed by adding 12 units of porcine mucosa heparin to the ACT tube (International Technidyne, celite type). Before anticoagulation, 4 mL of blood was drawn from the patient arterial line. Following the manufacturer’s instructions, 2 mL of blood was added to each tube (ACT-baseline and ACT-AST). Three minutes after anticoagulation with 4 mg heparin/kg body weight, a second sample (ACT-CPB) was taken to determine anticoagulation adequacy. The ACT times of each sample were recorded for 300 procedures occurring during 2004 and were retrospectively reviewed. Heparin resistance occurred in ∼20% of the patients (n= 61). In 54 patients, heparin resistance was predicted by the ACT-AST. This was determined by the presence of an ACT-AST time and an ACT-CPB that were both <480 seconds. The positive predictive value was 90%, with a false positive rate of 3%. Heparin resistance occurs in patients undergoing CPB. We describe a simple and reliable test to avoid the delays of assessing anticoagulation for CPB (90% positive predictive value). Depending on program guidelines, patients can be given additional heparin or antithrombin III derivatives to aid in anticoagulation. An additional ACT must be performed and reach target times before CPB initiation. Testing of patient blood before the time of incision for sensitivity to heparin is a way to avoid a delay that can be critical in the care of the patient. Commercial tests are available, but efficacy data are limited, and they lead to added inventory expense. This method of titrating a diluted heparin additive, mixed with patient blood in a familiar ACT test, has proven to be an inexpensive and reliable test to predict patient’s sensitivity to heparin.
Transfusion and Bleeding in Coronary Artery Bypass Grafting: An On-Pump Versus Off-Pump Comparison
Authors: Potger Kieron C. , McMillan Darryl , Southwell Joanne , Connolly Terry , Smith Kate Kingsford , BNurs Mark Ambrose
Published: July 2023

Blood transfusion rates in coronary artery bypass grafting (CABG) surgery using cardiopulmonary bypass (CPB) are typically higher compared with off-pump CABG (OPCAB). However, few studies have specifically examined intraoperative hemodilution as a contributing factor. The aim of this retrospective review was to compare the effect of using CPB or OPCAB on red blood cell (RBC) transfusion and postoperative bleeding. The lowest intraoperative hematocrit (Hct) was used as marker of intraoperative hemodilution. We reviewed the perioperative data of all isolated CABG patients at a metropolitan hospital from January 2003 to June 2005. Stepwise regression analyses were performed to determine whether CPB was an independent predictor of RBC transfusion, reoperation for bleeding, or postoperative chest drainage. Of a total of 1043 patients, there were 433 CPB and 610 off-pump cases. CPB use was not significantly related to increased RBC transfusions (odds ratio [OR], 0.98; 95% confidence interval [CI], 0.63–1.52;p= .921) and was associated with a lower incidence of reoperations for bleeding (OR, 0.4; 95% CI, 0.2–0.8;p= .009). There was less chest drainage over the first 12 hours in patients undergoing CPB (p< .0001); however, total postoperative chest drainage was not significantly related to operative procedure (p= .122). The lowest documented intraoperative Hct was a significant factor in RBC transfusions (OR, 0.89;p< .0001), an increased reoperation rate for bleeding (OR, 0.9;p= .001) and more postoperative chest drainage (log10-transformed: at 12 hours, b = −0.009,p< .0001; total, b = −0.006,p< .0001). CPB is not an independent risk factor in the incidence of RBC transfusions and is not associated with increased postoperative bleeding for isolated CABG. However, intraoperative hemodilution is an independent risk factor, with a lower intraoperative Hct associated with more RBC transfusions, increased reoperations for bleeding, and increased postoperative chest drainage. Addressing intraoperative hemodilution is important in minimizing CPB-associated morbidities.
A Report of Perfusion Staffing Survey: Decision Factors That Influence Staffing of Perfusion Teams
Authors: Conliffe Jacqueline A. , Riley Jeffrey B. , Clutter Jill , Wolf Kay , Murtha Sean
Published: July 2023

Health care organizations are becoming increasingly aware of the issues surrounding safe staffing because it affects all of us: the patient, public, profession, policy makers, and employers. The conduct of perfusion has been researched, but environmental factors surrounding perfusion have not. The intent of this study was to identify the current perfusion staff to case ratio, the decision factors used to make staffing decisions, and the relative importance of the factors to staff requirements. A survey instrument was constructed. The questionnaire contained four sections: Hospital Information, Perfusionist Information, Staffing Information, and Additional Feedback. Questionnaires were electronically mailed to American Society of Extracorporeal Society (AmSECT) members who were registered on Perflist. Response rate was monitored, and a follow-up survey was sent. Unfortunately, respondents were not compared statistically with the population on like characteristics, because AmSECT does not currently have information regarding the characteristics of their PerfList members. The staff to perfusion case ratio for 2006 was 120 ± 46 (SD) cases. The top three factors used by perfusionists to determine the number of staff to hire were the number of heart cases, on-call requirements, and the number of operating rooms. The reported use and importance of the decision factors did not differ significantly when reported by chief perfusionists, clinical perfusionists, or those who reported being involved in staffing. On-call requirements were reported to be used significantly more by chief perfusionists and by high activity perfusion teams when determining the number of staff to hire. Small hospitals tended to use staff experience, medium-sized hospitals reported using the number of operating rooms more often, and larger hospitals used the number of hospitals covered to determine staff requirements. Staffing a perfusion team is a difficult task, and many factors need to be considered. This survey provided a description of the current managerial staffing environment and practice. Further research surrounding the application of these factors to staff scheduling is needed.
Human Factors and the Cardiac Surgical Team: A Role for Simulation
Authors: Merry Alan F.
Published: July 2023

Human factors play an important role in determining the outcome of cardiac surgery. The interaction of humans with their equipment, and with each other in teams, is critical to success. Simulation provides a means of teaching and assessing the technical and non-technical skills of clinicians and can facilitate research into interventions to improve safety. Simulation in anesthesia has taken much from aviation and provides a model that could be extended to perfusion. The cost of setting up a simulation center (or even of adding a perfusion simulator to an existing center) is relatively high, but the potential return on this investment is also substantial, particularly at a time when access to patients for teaching and research is becoming harder. Different degrees of complexity and fidelity in simulation lend themselves to different objectives, whether in teaching, assessment, or research. In the longer term, comprehensive simulations of cardiac surgical procedures involving all participants in meaningful simulated roles may be possible.
What Is Optimal Flow and How to Validate This
Authors: De Somer Filip
Published: July 2023

Since the introduction of cardiopulmonary bypass, clinicians have tried to define the optimal blood flow for a given patient. The difficulty in determining a correct blood flow lies in the fact that cardiac surgery is done in a very inhomogeneous population, from neonates to the octogenarian, and often under non-physiologic conditions (hypothermia, hemodilution, low flow, etc.). Although clinicians acknowledge that maintaining a minimum oxygen delivery is more meaningful than using a fixed flow rate based on the metabolic needs of awake resting volunteers, the latter is most used in clinical practice. This is explained by the fact that no values are available on critical oxygen delivery for adequate tissue oxygenation under a given clinical condition. This was an overview of the relevant literature. In most centers, perfusionists use in-line monitoring, such as venous saturation or venous blood gases, for estimation of adequacy of tissue perfusion. Unfortunately, these oxygen-derived parameters have a poor correlation with anaerobic energy supply. Measurement of intermittent whole blood lactate concentration is used to compensate for this poor relationship, but as it monitors the concentration at given time points, it precludes optimally timely intervention by the perfusionist. The physiologic buffering by bicarbonate of the acid generated by converting pyruvate into lactate will produce carbon dioxide. As a consequence, carbon dioxide-derived parameters do have a good correlation with inadequate tissue perfusion. In-line monitoring of carbon dioxide production gives real-time information on tissue perfusion. Use of a standard reference flow for each patient is a poor option, because it does not reflect the metabolic need of the patient. Oxygen-derived parameters, such as venous saturation or partial venous oxygen tension, are poor predictors of anaerobic metabolism. A combination of intermittent whole blood lactate measurement with carbon dioxide-derived parameters predicts anaerobic energy production and allows proactive intervention by the perfusionist.
Arterial Line Filters Ranked for Gaseous Micro-Emboli Separation Performance: An In Vitro Study
Authors: Riley Jeffrey B.
Published: July 2023

Arterial line filters (ALFs) are arguably the most important component in the cardiopulmonary bypass circuit to protect the patient from gaseous macro-and micro-emboli (GME) originating in the perfusion circuit. The GME separating ability of 10 ALFs was ranked according to seven performance criteria. Ten ALFs rated between 20 and 43 μm were evaluated for flow resistance, the count, size, and volume of GME passed after a 10-mL room air bolus, and the ability to separate a high-count, 10-to 200-μm flowing distribution of GME. The Luna Innovations EDAC™ emboli detector was used to size, count, and sort GME. Three test trials were conducted for 3 each of the 10 filters. Performance criteria were correlated by regression analysis, statistically compared using analysis of variance, or ranked using non-parametric tests. Significance was set at 0.05. Weighting all seven test parameters equally, the most effective ALFs were the Cobe 21 and Gish 25-μm filters. The Pall LG-6 ranked more efficient than the Medtronic 20 and Dideco 27-μm filters. The Cobe 43, Terumo 40, Medtronic 38, Terumo 37, and Gish 40-μm filters were less effective as a group compared with the other filters. For the 10 filters, blood flow resistance was not correlated to rated pore size. Generally, the smaller the pore rating, the higher the GME separation ability rank, except for the leuko-reduction filter, which performed more effectively than other large pore filters.
Factors That Influence the Ability to Perform Autologous Priming
Authors: Trowbridge Cody , Stammers Alfred , Klayman Myra , Brindisi Nicholas
Published: July 2023

The purpose of this study was to determine which factors impact the ability to perform autologous priming (AP) of the extracorporeal circuit. Second, the effects of differential AP on transfusion and volume requirements were evaluated. After institutional review board approval, demographic, operative, volumetric, and transfusion data were prospectively collected on 100 adult patients undergoing cardiopulmonary bypass (CPB). Two analyses were conducted: AP Taken and percent AP Given. For each analysis, three groups were created based on standard distribution. Group A included patients within less than mean – 1 SD (≤500 mL AP Taken or ≥90% AP Given back), group B included patients within mean ± 1 SD (501–1299 mL AP Taken or 11%–89% AP Given back), and group C included patients greater than mean + 1 SD (≥1300 mL AP Taken or ≤10% AP Given back). Weight, pre-CPB hematocrit, clinical severity, and pre-CPB volume balance did not differ between the groups. Significant differences existed in AP Taken and percent AP Given between individual perfusionists. More AP was given back with higher urine output (group A: 846 ± 700 mL, group B: 613 ± 414 mL, group C: 384 ± 272 mL;p= .004), more autotransfusion [group A: 0 (0,1300 mL), group B: 0 (0,500 mL), group C: 0 (0,250 mL);p= .008], and less AP Taken [group A: 800 (0,1300 mL), group B: 1000 (200,1600 mL), group C: 1000 (800,1600 mL);p= .001]. When more AP was taken, CPB hematocrit was higher (group A: 22.3% ± 4.8%, group B: 25.6% ± 4.7%, group C: 26.6% ± 4.3%;p= .032), and fewer patients received red blood cells (group A: 64.3%, group B: 28.3%, group C:14.3%;p= .017). Some perfusionists were able to remove more AP before CPB. When more AP was taken, CPB hematocrit was higher, fewer patients received a transfusion, and less AP was given back. More AP was also given back with higher urine output and higher blood loss to the autotransfusion device.
Argatroban in Short-Term Percutaneous Ventricular Assist Subsequent to Heparin-Induced Thrombocytopenia
Authors: Webb David P. , Warhoover Matthew T. , Eagle Susan S. , Greelish James P. , Zhao David X. , Byrne John G.
Published: July 2023

Heparin-induced thrombocytopenia paradoxically is a transient pro-thrombotic disorder triggered by heparin exposure. If not treated appropriately, it can be life threatening because of its related thromboembolic complications. In particular, it presents a unique challenge in patients needing extracorporeal life support, because anticoagulation is essential for safe management. This case report describes the safe, efficacious use of Argatroban during short-term support of a patient with a percutaneously inserted left ventricular assist TandemHeart device.
Evaluation of the Doppler Technique for Fat Emboli Detection in an Experimental Flow Model
Authors: Wikstrand Victoria , Linder Nadja , Engström Karl Gunnar
Published: July 2023

Pericardial suction blood (PSB) is known to be contaminated with fat droplets, which may cause embolic brain damage during cardiopulmonary bypass (CPB) This study aimed to investigate the possibility to detect fat emboli by a Doppler technique. An in vitro flow model was designed, with a main pump, a filter, a reservoir, and an injector. A Hatteland Doppler probe was attached to the circulation loop to monitor particle counts and their size distribution. Suspended soya oil or heat-extracted human wound fat was analyzed in the model. The concentrations of these fat emboli were calibrated to simulate clinical conditions with either a continuous return of PSB to the systemic circulation or when PSB was collected for rapid infusion at CPB weaning. For validation purpose, air and solid emboli were also analyzed. Digital image analysis was performed to characterize the nature of the tested emboli. With soya suspension, there was an apparent dose response between Doppler counts and the nominal fat concentration. This pattern was seen for computed Doppler output (p = .037) but not for Doppler raw counts (p = .434). No correlation was seen when human fat suspensions were tested. Conversely, the image analysis showed an obvious relationship between microscopy particle count and the nominal fat concentration (p < .001). However, the scatter plot between image analysis counting and Doppler recordings showed a random distribution (p = .873). It was evident that the Doppler heavily underestimated the true number of injected fat emboli. When the image analysis data were subdivided into diameter intervals, it was discovered that the few large-size droplets accounted for a majority of total fat volume compared with the numerous small-size particles (<10 μm). Our findings strongly suggest that the echogenecity of fat droplets is insufficient for detection by means of the tested Doppler method.