 Good morning, I'd like to thank Debbie and the conference planning committee for inviting me to speak today I wish I could be there in person, but I'm happy to participate in this virtual environment My talk today will be on Clamplis cardioplegia Technique that we utilize at Cincinnati Children's Hospital. I have no disclosures I'll be talking about the development of a Clamplis cardioplegia protocol and the use of this technique on six patients between 2016 and 2019. The one thing that all of these patients had in common is that they were all very complex patients who were unable to be cross-clamped with conventional technique The inability to use a cross-clamp, especially if you realize it during the dissection process of a nine-time redo, presents a unique and difficult situation We founded our institution We need to utilize various methods of delivery as well as a rest solution in order to optimize the surgical repair for our patient Clamplis or systemic cardioplegia may not be the most elegant form of cardioplegia in your toolbox But it's great to have when the aortic cannot be cross-clamped or the risks of doing so outweigh the benefits I think you'll all agree that our patients have evolved along with our surgical techniques They're presenting to the cardiaco are sicker than ever before The patients in our practice at Cincinnati Children's Hospital over the last year and a half have been some of the most complex patients I've seen in the 36 years I've been in perfusion Cross-clamping the aorta is not a benign process It can lead to immediate or late aortic dissection or rupture as indicated in the literature Although the documented incidence is relatively low We all know that when it happens it can be catastrophic And the law of the lever states that the tissue near the hinge of the cross clamp is under more stress Than the tissue that's distal to the hinge and this unequal pressure distribution Is what occurs that injures the native aorta or the neo aortas In 2016 a patient presented to our institution whose pathology made it impossible to apply a standard cross-clamp and cardioplegia technique It was necessary to arrest the heart and perform D-pipal thermic circulatory arrest without cross-clamping the aorta The clampless cardioplegia technique had never been attempted at our institution But our lead surgeon had used it at another facility This process has become affectionately referred to at our institution as san quentin cardioplegia And in order to utilize this new technique our team developed a task force to develop a process That included a team of pharmacists cardiac surgeons and perfusionists We created a pharmacy order set and an algorithm for calculating the dose the induction dose of systemic cardioplegia The induction dose is simply 0.02 mil equivalents of kcl times the patient's total circulating volume Which as we all know is circulating blood volume plus the prime volume in the pump That will equate to a serum potassium level of 20 mil equivalents per liter And when you add the patient's existing serum potassium level to this you approximate the 26 mil equivalent per liter concentration that most cardioplegic solutions have today And the final concentration of solution is prepared in one mil equivalent per ml doses and put into 60 ml syringes The epic order set was created and it was created so that you could not pull up the order set by typing in common terms like cardioplegia Or potassium chloride you could only access it by typing clampless cardioplegia And this was a safety mechanism put in place to prevent it from accidentally being ordered for a patient and Prevented a lethal dose of cardioplegia to be given The order can only be placed by an attending cardiac surgeon who has to include the patient circulating blood volume information The prime volume and the requested dose of potassium chloride A verbal order can be placed in emergencies and when the order comes in to pharmacy They verify the dosage and a backup dosage is prepared along with every induction dose in the event that we need to give an additional amount of cardioplegia during the case The dose cannot be picked up But cannot be delivered anywhere in the hospital. It can only be picked up by a perfusion since we are Really aware of what the solution is and how lethal it can be if not given to a patient on bypass The dose is verified again between the primary and backup perfusions in the operating room The primary dose is kept on the pump and the backup dose is stored in the perfusion cart Out of the way, so it won't be accidentally picked up and used on another patient accidentally So the delivery process is typically we will cool the patient to the desired temperature a lot of times It's 18 degrees all ultra filtration is discontinued immediately after Administering the dose in order to not decrease the systemic concentration of potassium chloride And the full dose of systemic cardioplegia is given into the pump manifold After the heart arrest and the kcl as well distributed Deep hypothermic circulatory arrest is usually initiated So I have a set of two slides for each patient that i'm going to present And I want to describe what information is on each slide as i'll have to run through the information fairly quickly in order to meet the Time requirements for this talk The first slide which is this one Describes the patient diagnosis the prior surgical history and the clampless surgical procedure The second slide in each series outlines the cardioplegia dose The fluctuation in potassium concentrations and the dilutional ultra filtration volumes that we Remove to manipulate the final serum potassium concentration As well as the bypass on off and muff time So this is our first patient It was a fourth time redo on a three month old 3.9 kilogram female Who had an original diagnosis of hypoplastic left heart with aortic and mitral atresia Prior surgeries included a norwood with a santo shunt and due to worsening sinosis the santo shunt was revised nine days After the initial norwood and then there was an emergent conversion to a bt shunt with continuing hypoxia and desaturations Which led us to schedule the clampless procedure six days later Which was a revision of a bt shunt to a central shunt And the reason for the clampless procedure on this case was that the surgeon had to sew the proximal end of the central shunt To the ascending neo aorta and there physically wasn't enough room to do that and place a cross clamp So for this procedure, we gave 10 mil equivalents of kcl administered through the manifold to the patient After reaching 18 degrees and this resulted in immediate arrest followed by 18 minutes of depipothermic circulatory arrest Now in this second slide, you'll see that in the upper right hand corner will be the bypass times Circular rest times integrates ruble times the green bars on the left will show cardioplegia Concentrations the fluctuation serum potassium and the dilution ultrafiltration volumes that we removed during the course of bypass on the graph itself the blue columns represent the potassium concentrations and it's graduated to the left vertical axis and the Fluctuation fluctuations in ultrafiltration that were removed is this gold line, which is graduated against the right Vertical access the prior to arrest on this patient the potassium was 2.5 millimoles per liter The blood gas was drawn after Circular rest that showed the potassium increase to 6.5 millimoles per liter Which was a 2.6 increase from the baseline value We utilized dilution ultrafiltration routinely during the entire course of bypass on all of our patients and the routine wash solution that we utilize Is plasma light a with 20 mil equivalents of bicarb and 200 milligrams of calcium chloride added per liter In extreme cases of hyperkalemia and hypernatremia. We utilize normal saline or half normal saline to control those electrolyte levels Duff was started on this patient after the Circulatory arrest period during the rewarming phase We removed 2100 ml of total effluent which was six and a quarter times the patient circulating blood volume during two hours of bypass That resulted in a potassium value of 3.9 millimoles per liter after modified ultrafiltration And the cardioplegia administer during the case will be Visualized by a drop down arrow from the top Our second patient was the first patient after the clampless policy was in place. The patient was a 28 year old 70 kilogram female This patient was also the fourth patient in this series Her original diagnosis was a type 1 trunkus Prior surgeries included eight sternotomies Three neo aortic valve replacements five RV to pa heterographed and oligraft conduit replacements and a trans catheter rpa span The reason for the clampless procedure Was the patient presented with a pulsatile mass and the super sternal notch Due to a large pseudo aneurysm that originated from the distal anastomosis of the previous ascending aortic cortex graft The location of the pseudo aneurysm made it impossible to cross plant the aorta So this was a ninth time reduced sternotomy for resection of the ascending aortic pseudo aneurysm The patient was cooled to 18 degrees and administered 110 mili equivalent of spasm chloride, which caused a full arrest within one minute This was followed by three periods of circa rest and two periods of anigrate cerebral perfusion over the next two hours on bypass An additional half dose of del nido cardioplegia, which is indicated by the yellow area The yellow arrow The half dose was 10 mls per kilo of del nido was administered 122 minutes after the clampless dose The serum potassium rose from 3.8 to greater than 14 millimoles per liter and the post muff Potassium was 4.1 the total potassium delivered on this patient was 125 mil equivalents And we removed almost eight liters of fluid through delusional ultrafiltration Which was almost two times the patient circulating blood volume during 4.2 hours on bypass Patient number three was a nine kilogram one year old male with two prior sternotomy His original diagnosis was a dorv with a v transposition sub pulmonary dsd and an interrupted aortic arch Prior surgeries were a repair an arterial switch repair a dorv with aortic arch repair and direct anastomosis of the interrupted aortic arch This was done at an outside hospital that Resulted in a very short aorta with the coronaries implanted very high on the aortic root And this was a reason for utilizing a clampless cardioplegia solution on this patient because there was no room to apply a clamp The clampless procedure was a third time reduced sternotomy tubular extension of the ascending aorta LPA and mpa plasty rbot work and a bsd enclosure We cooled this patient to 18 degrees At the heart arrested within seconds after the clampless dose with 20 mil equivalents And that was followed by three periods of hypothermic circulatory rest in one period of anagrade cerebral perfusion So on this patient, uh, there were osteal doses of del nido cardioplegia Given after the clampless dose of 25 mls per per kilo total And this was given 66 minutes after the clampless induction followed by 10 mls per kilo a half dose of anagrade del nido two hours later Serum potassium rose from 4.1 to 9.5 And the post muff k was 4.4 with the final serum potassium in the or being 3.3 Prior to transport to the icu the total potassium delivered on this patient was 26 mil equivalents And we removed four liters of effluent, which was five and a quarter times the patient circulating blood volume during five hours on bypass patient number four Was a 69 year old 29 69 kilogram 29 year old female with nine prior sternotomies The original diagnosis was a type one trunkus and the patient was also our second patient in this series The reason for the clampless procedures the patient had endocarditis with vegetations on our aortic valve And there was no clear indication of how far they extended up into the ascending aorta So the surgeon did not want to clamp the aorta and risk embolizing the patient Um, it was a tenth time reduced sternotomy Bental procedure Exposition of handcock RV to pa conduit and reconstruction RPA intravascular scent removal and an rca coronary arterial plastic We cooled this patient to 18 degrees and administered the clampless dose of 110 mil equivalents of kcl causing a full arrest However, there was return of a minor h rel activity within two minutes So then additional half dose which was 60 mil equivalent Was given causing complete and sustained arrest and this was followed by nine periods of depipothermic circulatory arrest So as you can tell from this graph, this was a crazy case for us Uh, the patient received a total of 2.5 doses of clampless cardioplegia Which equaled a total of 280 mil equivalents of kcl There were three osteal and two anograde doses of del nido cardioplegia For a total of an additional 80 mil equivalents of potassium chloride for a grand total of 360 mil equivalents Of potassium chloride given to the patient over almost eight hours of bypass The serum potassium rose from 3.6 to 9.0 after the first one and a half doses of clampless And the highest serum potassium was 11.4 after the second full clampless dose and the first anograde dose of del nido cardioplegia The post muff potassium was 6.9 and the last serum potassium in the operating room prior to transport to the icu was 5.7 millimoles per liter For the delusional ultrafiltration data, we removed a whopping 16 and a half liters of effluent from this case Which equaled four times the patient circulating blood volume And to give you an idea of what the wash solution was that we used on this particular patient because the amount of passing was so excessive The 16 and a half liters included nine liters of normal saline 3.3 liters of half normal saline 5.2 liters of plasma life over a 7.8 hour pump run Patient number five was a frequent flyer with our program and went on to have an abo incompatible transplant Three months later. It was a 6.6 kilogram four-month-old patient with three prior sternotomies The original diagnosis was a complex single ventricle DILV with a d transposition co-arctation of the aorta and the patient also had a hyper coagulable state Prior surgeries included a norwood procedure with a dt shunt The patient had several thrombotic shunt occlusions and e cpr recovery with an av echmo run and multiple spence bt shunt There was an eventual bidirectional blend done with a subsequent cervical av fistula created in response to continued hypoxia In the patient after the bidirectional gland had been completed The reason for the clampless procedure was the surgeon could not clamp the neoreaorta and the clampless cardioplegia was ordered By a verbal order from the surgeon while dissecting 40 minutes prior to initiating bypass So it was really important in this particular Patient that we were able to place a verbal order because we were not planning on doing it at the start of the case The surgical procedure was the third time reduced sternotomy for a failed glen physiology a take down bidirectional gland rpa and sbc reconstruction and the implantation of a right modified bt shunt We cooled this patient to 30 degrees and 16 mill equivalents of kcl was used to arrest the heart There was no additional cardioplegia given besides the clampless dose the serum potassium rose from 2.7 to 14 The post muff serum potassium was 5.4 And the final serum potassium in the o r prior to transport to the icu was 4.9 millimoles per liter Ultra filtration we removed four times the circulating blood volume during three and a half hours on bypass And finally our last patient patient number six was an 80 year old 80 kilogram excuse me 52 year old patient Female patient with five prior sternotomies the original diagnosis was tetralogy of flow And her prior surgeries included a palliation with a waterson shunt at two months of age Which ended up being the main reason she required a clampless procedure This palliation made the order spiff and immobile and it could not be dissected and freed up circumferentially To accommodate a cross clamp The patient had a complete TET repair at four years of age three additional RVOT repairs at 7 10 and 41 years of age and at 51 years of age She had a melody valve placed which six months later nearly completely occluded With vegetations from endocarditis putting her into acute right heart failure with sepsis and hypoxia So her clampless procedure was an emergent six-time reduced sternotomy She was placed on femoral bypass prior to the sternotomy to decompress the heart Cooled the patient to 18 degrees and administered 108 mil equivalents of pacl There was an immediate arrest followed by 31 minutes of depipothermic circulatory arrest The serum potassium on this patient increased two and a quarter times from 4.1 to 9.0 The post-month serum potassium was 5.2 And the final serum potassium in the OR was 4.3 prior to transport From a dilution ultrafiltration standpoint, excuse me We removed 7.7 liters of effluent which was 1.75 times her circulating blood volume during five hours and 41 minutes of bypass So in summary the average increase in serum potassium with our clampless cardioplegia process was 3.1 times the patient's baseline value in the operating room All serum potassium values were within normal ranges at the end of modified ultrafiltration Except for one outlier the 6.9 value This was a patient that received an excessive 360 mil equivalents of kcl during bypass And even this patient's value was within normal ranges prior to leaving the operating room for transport to the icu And none of the patients showed any significant potassium rebound The increase is 24 hours post-op from the baseline values in the operating room So in summary, there are a wide variety of cardioplegia formulations and strategies that are available with really no optimal formula That's well defined for every surgeon in every surgical situation We feel at Cincinnati Children's Hospital that you need to integrate various methods of cardioplegia Delivery as well as different myocardial preservation solutions in order to optimize the surgical repair for our patients This series of patients showed no cardiac functional change by post-op echo and there were no perioperative complications to report The use of this technique has allowed us to successfully operate On patients at our facility that would have been considered inoperable with other more conventional techniques. Thank you very much