Adapting and applying student-centered learning in a perfusion clinical rotation.

While the process of teaching student perfusionists has been in development since the 1950s, the publication of the processes to improve perfusion clinical education has been largely lacking. Publications regarding education from other allied health and medical fields have shown the value of student-centered learning. The use of reflective practice to move perfusion students from thinking about actions after cardiopulmonary bypass (CPB) to reflecting and reacting on actions during CPB is better encouraged by moving from a teacher-centered to a student-centered clinical model. Our institution's teaching process has developed into a multi-point procedure to make our students into reflective practicing clinicians. Student preceptor evaluations were reversed to allow the students to evaluate themselves first, with feedback from the preceptor given subsequently. Additionally, a biweekly student educational session, where the student chooses a topic and reviews current evidence-based practice, was instituted. The clinical program director serves as the moderator and clinical expert to facilitate problem-based learning during the sessions. Students were also given three skill/experience levels with goals to reach and move through during the rotation. These student levels were also helpful to our preceptors in knowing what each student's skill level was throughout their rotation. Overall, moving from a teacher-centered to a student-centered clinical rotation has helped make students familiar with reflective practice, self-evaluation, evidence-based practice, and problem-based learning. The incorporation of these processes will hopefully lead students to become lifelong reflective perfusionists.

Using a Modified CPD Blood Bag to Store Blood from either ECMO or RRT Circuit Blood in Pediatric Patients.

By adapting a citrate phosphate dextrose (CPD) whole blood storage bag, residual blood from a renal replacement therapy (RRT) circuit can be saved in pediatric patients, decreasing in donor exposure later. The techniques used for autologous preoperative blood storage are the basis of storing the RRT circuit blood. The CPD anticoagulant has a benefit of having a commonly used reversal agent for its anticoagulant properties, i.e., calcium. Also, unlike the traditional anticoagulants used in extracorporeal membrane oxygenation (ECMO), i.e., heparin, and direct thrombin inhibitors, i.e., bivalirudin, there is no increase in anticoagulation laboratory parameters after administration. The CPD volume in the bag is reduced but keeps the original ratio the same between CPD and blood. This is accomplished by removing all CPD from the bag, adding back only the exact amount of CPD needed for the smaller amount of blood being transferred from the circuit. The RRT circuit managed at our institution uses 23 mL of CPD for 165 mL of circuit blood when stored with this technique. This calculation assumes a normal patient calcium level. This technique has been used successfully multiple times in more than 30 pediatric patients without incident for 7 years at our center. The CPD bag can also be used to store the residual blood from ECMO circuits after removal of ECMO to allow the blood to be given back to the patient at a later time by keeping the same citrate-to-blood ratio.

Dermabond as a Novel Solution for Needle-Hole Repair in Arterial Cannula while on Extracorporeal Membrane Oxygenation Therapy.

The annual incidence of extracorporeal membrane oxygenation (ECMO) for adult patients is increasing. Indications may vary from acute lung injury, ECMO-assisted cardiopulmonary resuscitation, to cardiac failure with an inability to wean from cardiopulmonary bypass. Complications may happen to the ECMO circuit, including cannula leaks from holes, cracks, or other damage, during the support period. Here, we present a novel solution for repairing a bleeding structural leak in the side of an arterial cannula. Dermabond was used to seal a small leak in the cannula likely caused by an earlier accidental needle puncture. Dermabond was applied to the area of damage, then allowed to cure, and wrapped with Ioban for increased stability. The patient was weaned from ECMO 2 days later without any complications from the repair of the cannula. The cannula was unable to be exchanged because of the small thoracotomy used to gain access for cannulation, so a repair was attempted. Moving the cannula to the femoral vessel was ruled out because of continued hypoxia and fear of creating a mixing cloud. Although less invasive incisions are becoming more common in cardiac surgery, these incisions for ECMO may be problematic if issues related to cannulas arise.

A novel wall water system for cardiopulmonary bypass may reduce the risk of aerosolized infection.

OBJECTIVE: Oxygenators for cardiopulmonary bypass require water flow for their integral heat exchanger. Heater-cooler units are nearly universally used for this requirement. Heater-cooler units pose the risk of aerosolized infection. The Centers for Disease Control and Prevention recommended discontinuing use of Stöckert 3T heater-cooler units (LivaNova PLC, London, United Kingdom) in October 2016 because of this risk. We aimed to reduce the risk of aerosolized infection posed by heater-cooler units by eliminating those devices from our operating rooms. METHODS: The cardiac surgery division collaborated with in-house specialties to engineer a novel wall water system. The design called for service to 4 operating rooms with the actual water mixing valve in an operating room closet. Remote temperature control was mounted next to the heart-lung machine. Primary safety systems built into the water system include 5 µm filtration, pressure regulating and relief valves, flow quantifiers, limits to the hot and chilled input temperatures, and a novel bridge near the heart-lung machine that allows the perfusionist to test the system before patient use and to quickly disconnect the patient in case of system malfunction. In addition, all water line connections can be made with the tubing drained and never under pressure. RESULTS: This novel wall water system has successfully provided heat exchanger water flow on 625 patients undergoing congenital heart surgery requiring cardiopulmonary bypass during its first 9 months of use. CONCLUSIONS: Wall water systems are an option for oxygenator heat exchangers that allow for improved heat exchange performance while reducing the risk of heater-cooler unit-associated infection during cardiac surgery.

Novel Applications of Modified Ultrafiltration and Autologous Priming Techniques to Reduce Blood Product Exposure on ECMO.

Patients needing the assistance of extracorporeal membrane oxygenation (ECMO) are at risk of hemodilution and, in some instances, may require exposure to large amounts of allogeneic blood products. Patient outcomes can be improved by taking steps to reduce transfusions and hemodilution. Currently, modified ultrafiltration (MUF) is used across the world to reduce hemodilution after cardiopulmonary bypass (CPB). Another common technique during bypass initiation is autologous priming. By applying modified versions of these techniques, ECMO patients may potentially benefit. Usually, patients requiring immediate transition from CPB to ECMO are not stable enough to tolerate MUF. Through alterations of the CPB and ECMO circuit tubing, MUF can be performed once on ECMO. Another technique to potentially lower the transfusion requirements for ECMO patients is a complete circuit blood transfer during an ECMO circuit exchange. While selective component changes are preferred if possible, occasionally a complete circuit change must be done. To minimize hemodilution or prevent priming with blood products, the original ECMO circuit's blood can be transferred to the new ECMO circuit before connecting to the patient. Both of these techniques, in our opinion, helped to reduce the number of transfusions that our ECMO patients have seen during these critical time periods.

Using Daily Plasma-Free Hemoglobin Levels for Diagnosis of Critical Pump Thrombus in Patients Undergoing ECMO or VAD Support.

Patients supported with extracorporeal membrane oxygenation (ECMO) or short-term centrifugal ventricular assist devices (VADs) are at risk for potential elevation of plasma-free hemoglobin (pfHb) during treatment. The use of pfHb testing allows detection of subclinical events with avoidance of propagating injury. Among 146 patients undergoing ECMO and VAD from 2009 to 2014, five patients experienced rapid increases in pfHb levels over 100 mg/dL. These patients were supported with CardioHelp, Centrimag, or Pedimag centrifugal pumps. Revolutions per minute of the pump head and flow in the circuit in three of the patients did not change, to maintain patient flow during the period that pfHb level spiked. Two patients had unusual vibrations originating from the pump head during the pfHb spike. Four patients had pump head replacement. Following intervention, trending pfHb levels demonstrated a rapid decline over the next 12 hours, returning to baseline within 48 hours. Two of the three patients who survived to discharge also experienced acute kidney injury, which was attributed to pfHb elevations. The kidney injury resolved over time. The architecture of centrifugal pumps may have indirectly contributed to red blood cell damage due to thrombus, originally from the venous line or venous cannula, being snared in the pump fins or pump head.

Cupriavidus pauculus bacteremia in a child on extracorporeal membrane oxygenation.

We report a case of bacteremia secondary to Cupriavidus pauculus in a 15-month-old boy on extracorporeal membrane oxygenation (ECMO). The source of the organism was water in the thermoregulator reservoir. The child responded well to cefepime and ciprofloxacin, a delayed oxygenator change out and replacement of the thermoregulator reservoir with a unit that was cleaned and decontaminated with sodium hypochlorite. Isolation of Cupriavidus pauculus from a patient on ECMO support should raise suspicion of the reservoir as a source.

Cold agglutinins in patients undergoing cardiac surgery requiring cardiopulmonary bypass.

OBJECTIVES: Cold agglutinins (CA) are circulating autoantibodies present in most humans. They are active below normal body temperatures. Cold hemagglutinin disease involves the presence of CA sufficiently active at temperatures in the periphery to produce hemolysis or agglutination. Systemic hypothermia and cold cardioplegia may result in agglutination or hemolysis. We reviewed the experience of a large referral center in managing patients with CA and cold hemagglutinin disease undergoing cardiac surgery requiring cardiopulmonary bypass. METHODS: The electronic medical records from 2002 to 2010 were searched to identify patients with CA or cold hemagglutinin disease who underwent cardiac surgery requiring cardiopulmonary bypass. Information related to preoperative CA testing and treatment, surgery, cardiopulmonary bypass, postoperative complications, and mortality was recorded. RESULTS: Sixteen patients underwent 19 procedures requiring cardiopulmonary bypass. Six patients had cold hemagglutinin disease. The identification of CA was made intraoperatively in 3 patients. One patient underwent preoperative plasma exchange. Cold blood cardioplegia was used in 2 of 16 procedures using cardioplegia, with the remaining using warmer blood cardioplegia. The lowest recorded intraoperative core temperature was less than 34 °C in 1 case. CA-related postoperative hemolysis requiring transfusion was present in 1 patient, which was resolved with active warming. No patient had evidence of permanent myocardial dysfunction, had a neurologic event, required dialysis, or died within 30 days. CONCLUSIONS: All patients with CA/cold hemagglutinin disease at the Mayo Clinic College of Medicine safely underwent cardiac surgery without major adverse morbidity or mortality. Patients with CA but without evidence of cold hemagglutinin disease can safely undergo normothermic cardiopulmonary bypass at 37°C and warm cardioplegia without further testing. Patients with cold hemagglutinin disease should undergo laboratory testing including CA titers and thermal amplitude and hematology consultation before cardiac surgery.

Inhaled carbon monoxide attenuates myocardial inflammatory cytokine expression in a rat model of cardiopulmonary bypass.

Carbon monoxide (CO), a by-product of Heme metabolism, is a potent modulator of inflammation. Low dose inhaled CO has demonstrated reduced lung and kidney injury in animal models of cardiopulmonary bypass (CPB). We evaluated the impact of low dose inhaled CO on systemic, pulmonary, and myocardial inflammatory response to CPB in rats. Sixteen male Sprague-Dawley rats underwent CPB for 1 hour. The CO (n = 8) group received inhaled CO at 250 ppm for 3 hours before CPB. The Air (n = 8) group served as the control. Pulmonary mechanics were assessed pre and post CPB. The animals were recovered for 30 minutes post CPB and subsequently sacrificed. Pre CPB and post CPB serum Tumor Necrosis Factor-alpha (TNF-alpha) and Interleukin-10 (IL-10) were analyzed by enzyme-linked immunosorbent assay. Gene expression array and real time quantitative polymerase chain reaction (PCR) analysis was performed on the extracted heart tissue. Baseline characteristics were similar between the groups with the expected exception of carboxyhemoglobin levels (p < or = .001) and oxyhemoglobin saturation (p < or = .01) in Air versus CO treated groups, respectively. Serum TNF-alpha (363 +/- 278 vs. 287 +/- 195;p = .13) and IL-10 (237 +/- 26 vs. 302 +/- 137; p = Not Significant) in Air versus CO groups respectively were not statistically different after CPB, despite showing a trend of inflammatory attenuation. Gene expression array of the myocardial tissue suggested a pattern of inflammatory modulation, which was confirmed by real time quantitative PCR demonstrating IL-10 expression 3.13 times higher (p = .02) in the CO treated group compared to the Air group. These data demonstrate that pretreatment with CO at 250 ppm may have a modulatory effect on the inflammatory response to CPB without compromising hemodynamics or oxygen delivery. Further investigation in a survival model of CPB is warranted.

Is the "sterile cockpit" concept applicable to cardiovascular surgery critical intervals or critical events? The impact of protocol-driven communication during cardiopulmonary bypass.

OBJECTIVE: There is general enthusiasm for applying strategies from aviation directly to medical care; the application of the "sterile cockpit" rule to surgery has accordingly been suggested. An implicit prerequisite to the evidence-based transfer of such a concept to the clinical domain, however, is definition of periods of high mental workload analogous to takeoff and landing. We measured cognitive demands among operating room staff, mapped critical events, and evaluated protocol-driven communication. METHODS: With the National Aeronautics and Space Administration Task Load Index and semistructured focus groups, we identified common critical stages of cardiac surgical cases. Intraoperative communication was assessed before (n = 18) and after (n = 16) introduction of a structured communication protocol. RESULTS: Cognitive workload measures demonstrated high temporal diversity among caregivers in various roles. Eight critical events during cardiopulmonary bypass were then defined. A structured, unambiguous verbal communication protocol for these events was then implemented. Observations of 18 cases before implementation including 29.6 hours of cardiopulmonary bypass with 632 total communication exchanges (average 35.1 exchanges/case) were compared with observations of 16 cases after implementation including 23.9 hours of cardiopulmonary bypass with 748 exchanges (average 46.8 exchanges/case, P = .06). Frequency of communication breakdowns per case decreased significantly after implementation (11.5 vs 7.3 breakdowns/case, P = .008). CONCLUSIONS: Because of wide variations is cognitive workload among caregivers, effective communication can be structured around critical events rather than defined intervals analogous to the sterile cockpit, with reduction in communication breakdowns.