Investigation of real-world heparin resistance and anticoagulation management prior to cardiopulmonary bypass: report from a nationwide survey by the Japanese Association for Thoracic Surgery heparin resistance working group.

OBJECTIVE: Heparin resistance is often encountered during cardiopulmonary bypass. Heparin dose and activated clotting time target values for the initiation of cardiopulmonary bypass are not yet universally standardized; further no consensus exists on the management of heparin resistance. This study aimed to investigate the current real-world practice on heparin management and anticoagulant treatment for heparin resistance in Japan. METHODS: A questionnaire survey was conducted at medical institutions nationwide with which The Japanese Society of Extra-Corporeal Technology in Medicine members are affiliated, targeting surgical cases with cardiopulmonary bypass performed from January 2019 through December 2019. RESULTS: Among 69% (230/332) of the participating institutions, the criterion for heparin resistance was defined as "the target activated clotting time value not reached even with an additional dose of heparin administration". Cases of heparin resistance were reported in 89.8% (202/225) of the responded institutions. Of note, 75% (106/141) of the responded institutions reported heparin resistance associated with antithrombin activity ≥ 80%. Antithrombin concentrate was used in 38.4% (238/619 responses) or third dose of heparin in 37.8% (234/619 responses) for advanced heparin resistance treatment. Antithrombin concentrate was found to be effective in resolving heparin resistance in patients having normal, as well as lower antithrombin activity. CONCLUSION: Heparin resistance has occurred in many cardiovascular centers, even among patients with normal antithrombin activities. Interestingly, the administration of antithrombin concentrate resolved heparin resistance, regardless of the baseline antithrombin activity value.

Cell-Free and Concentrated Ascites Reinfusion Therapy during Hemodialysis for Intradialytic Hypotension and Intractable Ascites.

A 60-year-old woman with POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes) syndrome and intractable ascites presented with acute renal failure and received hemodialysis (HD) therapy. Due to frequent intradialytic hypotension, ultrafiltration with cell-free and concentrated ascites reinfusion therapy (CART) was performed to adequately manage the body fluid status and massive ascites. During HD with CART, her blood pressure was maintained compared with that during HD without CART, and an ultrafiltration volume of 3.7 L was achieved after HD with CART. In HD patients with intradialytic hypotension and massive ascites, the combination of CART and ultrafiltration during HD may be an effective therapeutic option for body-fluid management.

Modified central extracorporeal membrane oxygenation for distended left ventricle.

A 38-year-old man who was resuscitated from ventricular fibrillation was diagnosed with acute aortic dissection complicated by coronary malperfusion. He underwent total aortic arch replacement and coronary artery bypass grafting to the left anterior descending coronary artery. Due to low cardiac output syndrome from cardiac ischemia, central extracorporeal membrane oxygenator (ECMO) was established with aortic cannulation from the side branch of the implanted prosthetic graft and venous drainage from the femoral vein. Ventricular venting was added from the right upper pulmonary vein for the distended left ventricle. ECMO was weaned off on postoperative Day 4. The patient is back on his normal daily life for more than 1 year after the surgery.

Minimized perfusion circuit for acute type A aortic dissection surgery.

A minimized perfusion circuit (MPC) may reduce transfusion requirement and inflammatory response. Its use, however, has not been standardized for complicated cardiovascular surgery. We assessed outcomes of surgery for acute type A aortic dissection (ATAAD) performed with a MPC under circulatory arrest. The study involved 706 patients treated surgically for ATAAD (by hemiarch repair [n = 571] or total arch repair [n = 135]). Total arch repair was performed using selective antegrade cerebral perfusion. Our MPC, a semi-closed bypass system, incorporating a completely closed circuit and a level-sensing reservoir in the venous circuit, was used. Clinical variables, transfusion volume, and outcomes were investigated in patients who underwent hemiarch repair or total arch repair. The overall incidences of shock, organ ischemia, and coagulopathy (prothrombin time-international normalized ratio >1.5) were 26%, 35%, and 8%, respectively. Mean extracorporeal circulation (ECC) time was 149 minutes for the hemiarch repair group and 241 minutes for the total arch repair group, respectively. No patient required conversion to conventional ECC, and there were no complications related to the use of the MPC. The need for transfusion (98% vs. 91%, P = .017) and median transfusion volume (1970 vs. 1680 mL, P = .002) was increased in the total arch repair group. Neither in-hospital mortality (total arch; 12% vs. hemiarch; 7%, P = .11) nor 10-year survival (74.4% vs. 68.4%, P = .79) differed significantly. Outcomes of surgery for ATAAD performed with the MPC were acceptable. The possibility of transfusion and transfusion volume remains high during such surgery, despite the use of the MPC.

Utility Of An Automatic Limulus Amebocyte Lysate Kinetic Turbidimetric Test For Endotoxin Screening Of Dialysate Samples.

BACKGROUND: Endotoxin contamination of dialysate has serious adverse effects on patients undergoing hemodialysis. Therefore, endotoxin activity in dialysate is closely monitored. Limulus amebocyte lysate (LAL) has been used as a reagent to measure endotoxin activity. Here, we investigated the efficacy of an automatic LAL kinetic turbidimetric test (Toxinometer ET-mini) for screening endotoxin activity in dialysate. METHODS: In total, endotoxin activity was measured in 110 dialysate samples obtained from several sites within hemodialysis circuits between June 2012 and March 2018. The results were compared with those from a conventional chromogenic substrate LAL test conducted by a clinical examination laboratory. RESULTS: Both the automatic LAL test and the chromogenic substrate LAL test had a minimum detection level of 0.001 endotoxin units (EU)/mL. Endotoxin activity levels measured via the automatic LAL test showed a strongly positive correlation (concordance correlation coefficient: 0.9933; 95% CI: 0.9902-0.9954) and good agreement (mean difference: 0.00±0.01 EU/mL) with those obtained using the chromogenic substrate LAL test. CONCLUSION: The results suggest that the automatic LAL test may be useful for endotoxin activity screening in hemodialysis facilities.

[Cardiopulmonary Bypass System and Perfusion].

In addition to maintaining circulation and gas exchange, the heart-lung machine is responsible for ensuring a bloodless field, retrieve of blood, suppression of metabolism, blood dilution and concentration, and myocardial protection. The heart-lung machine has 2 kinds of circuits having different characteristics, that is an open circuit and a closed circuit. Either a roller pump or a centrifugal pump is used in the machine. Gas exchange is performed by using a membrane type oxygenator. Venting, suction, myocardial protection circuit are important items in the machine. Safety devices and troubleshooting are required for safety management of the heart-lung machine.

Use of an extracorporeal circulation perfusion simulator: evaluation of its accuracy and repeatability.

Medical simulators have mainly been used as educational tools. They have been used to train technicians and to educate potential users about safety. We combined software for hybrid-type extracorporeal circulation simulation (ECCSIM) with a CPB-Workshop console. We evaluated the performance of ECCSIM, including its accuracy and repeatability, during simulated ECC. We performed a detailed evaluation of the synchronization of the software with the console and the function of the built-in valves. An S-III heart­lung machine was used for the open circuit. It included a venous reservoir, an oxygenator (RX-25), and an arterial filter. The tubes for venous drainage and the arterial line were connected directly to the ports of the console. The ECCSIM recorded the liquid level of the reservoir continuously. The valve in the console controlled the pressure load of the arterial line. The software made any adjustments necessary to both arterial pressure load and the venous drainage flow volume. No external flowmeters were necessary during simulation. We found the CPB-Workshop to be convenient, reliable, and sufficiently exact. It can be used to validate procedures by monitoring the controls and responses by using a combination of qualitative measures.

Survey of blood pump diaphragm damage in the NIPRO-ventricular assist device.

We surveyed the incidence of blood pump diaphragm damage (rupture or crack) in the NIPRO-ventricular assist device (VAD). In the cases in which rupture or suspected blood pump crack was detected, we disassembled the pumps to visually check the condition of the diaphragm after replacement or use. Of 366 blood pumps surveyed, diaphragm damage was observed in 2.7 %. The duration of use of the blood pumps with diaphragm damage was significantly longer than that of pumps without damage. The incidence of diaphragm damage increased with longer duration of use. On the basis of these findings, blood pump diaphragm damage in the NIPRO-VAD may be associated with duration of use. However, some blood pumps were used for prolonged periods without diaphragm damage. All blood pumps with damage had a crack in the diaphragm on the air chamber side near the diaphragm-housing (D-H) junction. Cracks were not found in any specific part of the diaphragm. In blood pumps with diaphragm rupture, the crack had a through-hole reaching the blood-contacting surface. Although we were unable to identify the causes of the cracks, it is suggested that when a crack appears in the diaphragm it will gradually expand and eventually lead to rupture. If a crack is detected in a blood pump, we advocate replacing the pump before it grows. When the NIPRO-VAD is used, it is necessary to keep in mind that blood pump diaphragm damage may occur.

Development of a new control device for stabilizing blood level in reservoir during extracorporeal circulation.

We developed a simple device that stabilizes the blood level in the reservoir of the extracorporeal circulation open circuit system by measuring the hydrostatic pressure of the reservoir to control the flow rate of the arterial pump. When the flow rate of the venous return decreases, the rotation speed of the arterial pump is automatically slowed down. Consequently, the blood level in the reservoir is stabilized quickly between two arbitrarily set levels and never falls below the pre-set low level. We conducted a basic experiment to verify the operation of the device, using a mock circuit with water. Commercially available pumps and reservoir were used without modification. The results confirmed that the control method effectively regulates the reservoir liquid level and is highly reliable. The device possibly also functions as a safety device.

Distribution of certified perfusionists in core training institutions accredited by the Japanese Board of Cardiovascular Surgery in Japan.

In 2008, the 22nd qualifying examination for certified perfusionist was conducted on extracorporeal circulation techniques. A total of 647 people had passed the qualifying examination and become certified perfusionists by the end of 2008.

[The Japanese guidelines for cardiopulmonary bypass and recommendations concerning safety devices for cardiopulmonary bypass].

In March 2007, under the guidance of the Ministry of Health, Labour and Welfare, a committee released Japanese guidelines for cardiopulmonary bypass (CPB) with the purpose to standardize CPB hardware and software for patient's safety and education of medical personnel. In April 2007, the Japanese Society of Extra Corporeal Technology in Medicine (JaSECT) released recommendations concerning safety devices for cardiopulmonary bypass. An on-site training session for CPB troubles was held at the 38th annual meeting of Japanese Society for Cardiovascular Surgery in February 2008 as a measure to ensure safety of CPB. Young heart surgeons and perfusionists were taught the basic CPB operations, recovering procedures after an incident, and the use of safety devices. A questionnaire survey was conducted at the end of the training session. Eight heart surgeons and 7 perfusionists (3 certified and 4 without certification) participated in the session None of the 8 heart surgeons who participated had read the guidelines or made an effort to accomplish the recommendations. Of the 7 certified or uncertified perfusionists who participated, only one certified perfusionist made an effort to accomplish the recommendation. CPB accidents are rare, but as a medical team, tragedies such as death and life-threatening complication due to CPB accident should be prevented at all costs. We believe that the 1st step to prevent CPB incident is to read and understand the CPB guidelines thoroughly, and to accomplish the "required" items listed in the recommendations.

Quantitative evaluation of hand cranking a roller pump in a crisis management drill.

The heart-lung machines for open-heart surgery have improved over the past 50 years; they rarely break down and are almost always equipped with backup batteries. The hand-cranking procedure only becomes necessary when a pump breaks down during perfusion or after the batteries have run out. In this study, the performance of hand cranking a roller pump was quantitatively assessed by an objective method using the ECCSIM-Lite educational simulator system. A roller pump connected to an extracorporeal circuit with an oxygenator and with gravity venous drainage was used. A flow sensor unit consisting of electromagnetic sensors was used to measure arterial and venous flow rates, and a built-in pressure sensor was used to measure the water level in the reservoir. A preliminary study of continuous cranking by a team of six people was conducted as a surprise drill. This system was then used at a perfusion seminar. At the seminar, 1-min hand-cranking drills were conducted by volunteers according to a prepared scenario. The data were calculated on site and trend graphs of individual performances were given to the participants as a handout. Preliminary studies showed that each person's performance was different. Results from 1-min drills showed that good performance was not related to the number of clinical cases experienced, years of practice, or experience in hand cranking. Hand cranking to maintain the target flow rate could be achieved without practice; however, manipulating the venous return clamp requires practice. While the necessity of performing hand cranking during perfusion due to pump failure is rare, we believe that it is beneficial for perfusionists and patients to include hand-cranking practice in periodic extracorporeal circulation crisis management drills because a drill allows perfusionists to mentally rehearse the procedures should such a crisis occur.

Certified perfusionists in Japan.

This year, the 20th qualifying examination on the extracorporeal circulation technique for a certified perfusionist was conducted. A total of 569 certified perfusionists had qualified in Japan up to November 2006.