Extracorporeal Cardiopulmonary Bypass Research Articles

Intermittent hemodialysis as a rewarming strategy for severe hypothermia in patients without renal failure: a case report

This case report highlights the effective use of intermittent hemodialysis (IHD) in warming a 71-year-old female patient with severe hypothermia who presented with a rectal temperature of 25 °C and signs of hemodynamic instability. The patient, found unconscious after prolonged exposure to cold exacerbated by alcohol consumption, initially showed some improvement in core temperature through active external rewarming methods. However, soon, her temperature plateaued at 27 °C. Patient was deemed unsuitable for extracorporeal membrane oxygenation (ECMO) or cardiopulmonary bypass (CPB) due to her age, and urgent IHD was initiated. This approach resulted in a stable increase in core temperature at approximately 2.0 °C/hr, along with normalization of lactic acidosis, creatinine phosphokinase, and correction of electrolyte imbalances, culminating in her full recovery and discharge after seven days in the hospital.After reviewing this case alongside similar ones from before, this case report highlights the efficacy and safety of IHD as an efficient, readily available, and less invasive method for rewarming moderate to severe hypothermic patients who are hemodynamically unstable patients but do not have cardiac arrest or renal dysfunction. IHD is especially useful when less invasive cooling devices (Artic Sun/ CoolGard) are not available or more invasive extracorporeal life support options (ECMO/ CPB) are either not indicated or unavailable. IHD can also help improve concurrent electrolyte imbalances and/or toxin buildup. The report further emphasizes the necessity of monitoring for potential complications, such as post-dialysis hypophosphatemia and rebound hyperkalemia, following successful rewarming.

Surgical Technique of Donation after Circulatory Death using Normothermic Regional Perfusion

Heart transplantation (HT) is the gold standard treatment of end-stage heart disease. Waitlist mortality remains high due to a shortage of available donor organs. Donation after circulatory death (DCD) has shown potential to increase transplant volumes by 15-20%%. Resuscitation of the organs after circulatory death can be performed ex vivo using machine perfusion or in situ using either extracorporeal membrane oxygenation (ECMO) or cardiopulmonary bypass (CPB). Thoracoabdominal normothermic regional perfusion (TA-NRP) entails reperfusing the heart in-situ after circulatory death. It also involves total body reperfusion under physiological conditions, correction of metabolic abnormalities, and allows unloading of the left ventricle to facilitate myocardial recovery. After weaning off support, direct visual and hemodynamic assessment of heart function is possible. Safe and expeditious establishment of cardiopulmonary bypass after death is the key to success of this technique. Here, we review the history of donation after circulatory death, our protocol and surgical technique of establishing TA-NRP with cold static preservation, and briefly describe the outcomes after DCD heart transplantation.

Research Progress on Influence of Centrifugal Blood Pump on Blood Injury

Centrifugal blood pumps drive blood flow by regulating blood flow rate, and have been widely used in clinical applications, including extracorporeal membrane oxygenation (ECMO), cardiopulmonary bypass (CPB), and extracorporeal circulation carbon dioxide removal (ECCO2R). However, because different structures and different forms of centrifugal pumps have different requirements for blood extracorporeal circulation in clinical application scenarios, blood pumps face different application conditions in clinical use. In this study, the effects of different structures of centrifugal pumps and different working conditions on blood damage are summarized for reference by relevant institutions and R&D personnel.

Extracorporeal membrane oxygenation versus cardiopulmonary bypass during transcatheter aortic valve implantation: a meta-analysis of survival benefits.

Extracorporeal membrane oxygenation versus cardiopulmonary bypass during transcatheter aortic valve implantation: a meta-analysis of survival benefits.

Biochemical Changes in Cardiopulmonary Bypass in Cardiac Surgery: New Insights.

Patients undergoing coronary revascularization with extracorporeal circulation or cardiopulmonary bypass (CPB) may develop several biochemical changes in the microcirculation that lead to a systemic inflammatory response. Surgical incision, post-CPB reperfusion injury and blood contact with non-endothelial membranes can activate inflammatory signaling pathways that lead to the production and activation of inflammatory cells, with cytokine production and oxidative stress. This inflammatory storm can cause damage to vital organs, especially the heart, and thus lead to complications in the postoperative period. In addition to the organic pathophysiology during and after the period of exposure to extracorporeal circulation, this review addresses new perspectives for intraoperative treatment and management that may lead to a reduction in this inflammatory storm and thereby improve the prognosis and possibly reduce the mortality of these patients.

Impact of intraoperative therapeutic plasma exchange on bleeding in lung transplantation

Our program uses a desensitization protocol that includes intraoperative therapeutic plasma exchange (iTPE) for crossmatch positive lung transplants, which improves access to lung transplant for sensitized candidates while mitigating immunologic risk. Although we have reported excellent outcomes for sensitized patients with the use of this protocol, concern for peri-operative bleeding appears to have hindered broader adoption of it at other programs. We conducted a retrospective cohort study to quantify the impact of iTPE on peri-operative bleeding in lung transplantation. All first-time lung transplant recipients from 2014-2019 who received iTPE were compared to those who did not. Multivariable logistic regression was used to determine the association between iTPE and large volume peri-operative transfusion requirements (≥5 packed red blood cell units within 24 hours of transplant start), adjusted for disease type, transplant type, and extracorporeal membrane oxygenation or cardiopulmonary bypass use. The incidence of hemothorax (requiring re-operation within 7 days of lung transplant) and 30-day post-transplant mortality were compared between the two groups using Chi square test. 142 patients (16%) received iTPE and 755 patients (84%) did not. The mean number of peri-operative pRBC transfusions was 4.2 among patients who received iTPE and 2.9 among patients who did not. iTPE was associated with an increased odds of requiring large volume peri-operative transfusion (OR 1.9; 95% CI: 1.2-2.9, p-value=0.007), but was not associated with an increased incidence of hemothorax (5% in both groups, p=0.99) or 30-day post-transplant mortality (3.5% among patients who received iTPE vs. 2.1% among patients who did not, p=0.31). This study demonstrates that the use of iTPE in lung transplantation may increase peri-operative bleeding, but not to a degree that impacts important post-transplant outcomes.

Initial experience and outcomes with a hybrid extracorporeal membrane oxygenation and cardiopulmonary bypass circuit for lung transplantation

BackgroundThe utilization of extracorporeal life support (ECLS) for intraoperative support during lung transplantation has increased over the past decade. Although veno-arterial extracorporeal membrane oxygenation (VA-ECMO) has recently emerged as the preferred modality over cardiopulmonary bypass (CPB), many centers continue to use both forms of ECLS during lung transplantation. Our novel hybrid VA-ECMO/CPB circuit allows for seamless transition from VA-ECMO to CPB at a significant cost savings compared to a standalone VA-ECMO circuit. This study describes our initial experience and outcomes in the first 100 bilateral lung transplantations using this novel hybrid VA-ECMO/CPB circuit. MethodsMedical records from September 2017 to May 2021 of the first 100 consecutive patients undergoing bilateral lung transplantation with intraoperative hybrid VA-ECMO support were examined retrospectively. We excluded patients with single lung transplants, retransplantations, preoperative ECLS bridging, and veno-venous (VV) ECMO and those supported with CPB only. Perioperative recipient, anesthetic, perfusion variables, and outcomes were assessed. ResultsOf the 100 patients supported with VA-ECMO, 19 were converted intraoperatively to CPB. Right ventricular dysfunction was seen in 37% of patients, and the median mean pulmonary artery pressure was 28 mm Hg. No oxygenator clotting was observed with a median heparin dose of 13,000 units in the VA-ECMO group. Primary graft dysfunction grade 3 at 72 hours was observed in 10.1% of all patients and observed 1-year mortality was 4%. ConclusionsThe use of a hybrid VA-ECMO/CPB circuit in our institution allows for rapid conversion to CPB with acceptable outcomes across a diverse recipient group at a significantly reduced cost compared to standalone VA-ECMO circuits.

The effects of nitric oxide on coagulation and inflammation in ex vivo models of extracorporeal membrane oxygenation and cardiopulmonary bypass.

Extracorporeal life support (ECLS) has extensive applications in managing patients with acute cardiac and pulmonary failure. Two primary modalities of ECLS, cardiopulmonary bypass (CPB) and extracorporeal membrane oxygenation (ECMO), include several similarities in their composition, complications, and patient outcomes. Both CPB and ECMO pose a high risk of thrombus formation and platelet activation due to the large surface area of the devices and bleeding due to system anticoagulation. Therefore, novel methods of anticoagulation are needed to reduce the morbidity and mortality associated with extracorporeal support. Nitric oxide (NO) has potent antiplatelet properties and presents a promising alternative or addition to anticoagulation with heparin during extracorporeal support. We developed two ex vivo models of CPB and ECMO to investigate NO effects on anticoagulation and inflammation in these systems. Sole addition of NO as an anticoagulant was not successful in preventing thrombus formation in the ex vivo setups, therefore a combination of low-level heparin with NO was used. Antiplatelet effects were observed in the ex vivo ECMO model when NO was delivered at 80 ppm. Platelet count was preserved after 480 min when NO was delivered at 30 ppm. Combined delivery of NO and heparin did not improve haemocompatibility in either ex vivo model of CPB and ECMO. Anti-inflammatory effects of NO in ECMO systems have to be evaluated further.

BIO2: Microcirculation Perfusion is Impaired up to 24 Hours after Veno-arterial Extracorporeal Circulation.

Extracorporeal circulation (ECC) procedures, such as extracorporeal membrane oxygenation (ECMO) and cardiopulmonary bypass (CPB), are used to replace the function of the heart and lung, but they induce complications in the form of acute kidney failure, bleeding, heart arrhythmias or thromboembolic complications. This study aimed to quantify the changes in microvascular perfusion and oxygenation that occur after veno-arterial ECC (VA-ECC). Male Golden Syrian hamsters were instrumented with a dorsal window chamber to study their microcirculation and an exteriorized carotid artery catheter for blood pressure and blood gas measurements. After baseline (BL) measurements were taken, the hamster underwent surgery under isoflurane to insert a drainage catheter into the jugular vein. A heparin bolus (0.05 IU/g) was then provided, and the animal was connected to the VA-ECC circuit, which consists of a peristaltic pump and bubble trap. The VA-ECC circuit was primed with either lactated ringers (LR) or 5% human serum albumin in saline (HSA). Blood flow was ramped up over 15 minutes, maintained at 15% of the animal’s cardiac output for 60 minutes, then ramped down over 15 minutes. Sham animals underwent cannulation surgery and heparinization but were not connected to the VA-ECC circuit. The animals were surgically closed, placed on a heating pad, and allowed at least 30 minutes to wake up from the anesthetic plane before taking measurements at 1, 2, and 24 hours after VA-ECC. Results show that flow in arterioles and venules (Figure 1) at all post-ECC timepoints statistically decreased in LR and HSA groups compared to Sham. LR and HSA failed to recover flow in arterioles and venules back to BL levels post-ECC. Interestingly, venule perfusion statistically increased at 1 and 2 hrs in the HSA group compared to the LR group. Functional capillary density (FCD, Figure 2) showed a statistical reduction in capillary perfusion for both ECC groups, with the HSA group maintaining higher levels compared to the LR group. Microvascular hemoglobin (Hb) oxygen (O2) saturation (Figure 3), in venules was statistically reduced post-ECC for both LR and HSA compared to Sham and BL. The microvascular perfusion results, combined with the consistent drop in hematocrit (Hct) post-ECC suggest an imbalance in oncotic pressure that slowly rectifies after ECC. Via Starling’s law of filtration, the priming volume dilutes protein content within the blood, causing the intravascular oncotic pressure to drop, resulting in ultrafiltration at the capillary level. Additionally, the drop in venule Hb O2 saturation and the reduced microvascular perfusion suggest a reduced O2 delivery and potentially a repayment of an O2 debt post-ECC. This study shows that microvascular sequelae could potentially cause ischemic injury in ECC procedures, which can lead to organ damage and inflammation.Figure 1. Microcirculatory hemodynamics. Diameter, velocity, and volumetric blood flow are shown from top to bottom, while arterioles (Sham: n = 38, LR: n = 33; HSA: n = 33) and venules (Sham: n = 38, LR: n = 30, HSA: n = 33) are shown from the left to right columns. All values are normalized to baseline (BL, before ECC) measurements for each vessel. * P < 0.05, ** P < 0.01, *** P < 0.001, **** P < 0.0001 between groups at each timepoint. † P<0.05 compared to BL, within each group.Figure 2. Functional capillary density (FCD). * P < 0.05, ** P < 0.01, *** P < 0.001, **** P < 0.0001 between groups. † P<0.05 compared to baseline (BL). N = 6 for all groups.Figure 3. Microvascular Hemoglobin Oxygen Saturation Changes. The top row shows arterioles (Sham: n = 19, LR: n = 13, HSA: n = 16), while the bottom row shows venules (Sham: n = 21, LR: n = 19, HSA: n = 22). * P < 0.05, ** P < 0.01, *** P < 0.001, **** P < 0.0001 between groups. † P<0.05 compared to baseline (BL).

EDCB ET AA: A Mnemonic for Resuscitating Hypothermic Patients Under Extreme Conditions

EDCB ET AA: A Mnemonic for Resuscitating Hypothermic Patients Under Extreme Conditions

Prevalence and Impact of Preoperative Peripheral Arterial Disease on Outcomes Following Geriatric Lung Transplantation

<h3>Purpose</h3> Elderly patients represent the fast growing population among the end-stage lung disease patients who seek for lung transplantation (LTx); however, their comorbidities often preclude the candidacy for LTx. Peripheral arterial disease (PAD) is one of such outstanding concerns. In this study, we sought the association of preexisting PAD and outcomes after LTx. <h3>Methods</h3> Patients over 70 years old who received LTx at our institution between 2018 and 2020 were enrolled (n=130). Preoperative CT of the abdomen and pelvis was reviewed for all the patients. Vascular calcifications on CT were assessed from distal aorta through femoral arteries by using a semi-quantitative 5-point scale. Then we divided the patients into three groups: mild (1), moderate (2, 3) and severe (4, 5). Data were compared between the three groups. <h3>Results</h3> Thirty-four patients (26%) were in the mild group, 65 patients (50%) were in the moderate group and 31 patients (24%) were in the severe group. Prevalence of pulmonary emphysema and concomitant coronary artery disease was significantly higher in the moderate and severe groups. Regarding the selection of intraoperative mechanical circulatory support including central vs. peripheral, extracorporeal membrane oxygenation vs. cardiopulmonary bypass vs. off-pump, there was no difference among the groups. Postoperatively, the recipients in the severe group demonstrated significantly higher incidences of primary graft dysfunction grade 2-3. Of note, the hospital mortality in the moderate group was the worst (10.8%) followed by the severe (6.5%) and mild groups (2.9%). The 1-year survival for the mild, moderate and severe groups was 90.1%, 81.2% and 87.1%, respectively (Figure 1A), whereas conditional long-term survival appears to be comparable among the groups (Figure 1B). <h3>Conclusion</h3> Pretransplant PAD assessment appears to play an important role in identifying the high risk elderly patients for major vascular complications as well as survival outcomes after LTx.

Control of Blood Coagulation by Hemocompatible Material Surfaces-A Review.

Hemocompatibility of biomaterials in contact with the blood of patients is a prerequisite for the short- and long-term applications of medical devices such as cardiovascular stents, artificial heart valves, ventricular assist devices, catheters, blood linings and extracorporeal devices such as artificial kidneys (hemodialysis), extracorporeal membrane oxygenation (ECMO) and cardiopulmonary bypass. Although lower blood compatibility of materials and devices can be handled with systemic anticoagulation, its side effects, such as an increased bleeding risk, make materials that have a better hemocompatibility highly desirable, particularly in long-term applications. This review provides a short overview on the basic mechanisms of blood coagulation including plasmatic coagulation and blood platelets, as well as the activation of the complement system. Furthermore, a survey on concepts for tailoring the blood response of biomaterials to improve the hemocompatibility of medical devices is given which covers different approaches that either inhibit interaction of material surfaces with blood components completely or control the response of the coagulation system, blood platelets and leukocytes.

Extracorporeal life support and cardiopulmonary bypass for central airway surgery: A systematic review.

Major airway surgery can pose a complex problem to perioperative central airway management. Adjuncts to advanced ventilation strategies have included cardiopulmonary bypass, veno-arterial, or veno-venous extracorporeal life support. We performed a systematic review to assess the existing evidence utilizing these strategies. An electronic search was conducted to identify studies written in English reporting the use of extracorporeal life support (ECLS) during central airway surgery. Thirty-six articles consisting of 78 patients were selected and patient-level data were analyzed. Median patient age was 47 [IQR: 34-53] and 59.0% (46/78) were male. Indications for surgery included central airway or mediastinal cancer in 57.7% (45/78), lesion or injury in 15.4% (12/78), and stenosis in 12.8% (10/78). Support was initiated pre-operatively in 9.9% (7/71) and at the time of induction in 55.3% (42/76). It was most commonly used at the time of tracheal resection/repair [93.2% (68/73)], intubation of the tracheal stump [94.4% (68/72)], and re-anastomosis [94.2% (65/69)]; 13.7% (10/73) patients were supported post-operatively. The most commonly performed surgery was tracheal repair or resection in 70.3% (52/74). Median hospital stay was 12 [8, 25] days and in-hospital mortality was 7.9% (6/76). There was no significant difference in survival between the three groups (p=.54). Extracorporeal membrane oxygenation offers versatility in timing, surgical approach, and ECLS runtime that makes it a viable addition to the surgical armamentarium for treating complex central airway pathologies.

Left Heart Decompression on Extracorporeal Membrane Oxygenation Support and Cardiopulmonary Bypass.

Left Heart Decompression on Extracorporeal Membrane Oxygenation Support and Cardiopulmonary Bypass.

Outcomes of extracorporeal membrane oxygenation and cardiopulmonary bypass in children after drowning-related resuscitation.

Drowning is one of the leading causes of accidental deaths in children worldwide. However, the use of long-term extracorporeal life support (ECLS) in this setting is not widely established, and rewarming is often achieved by short-term cardiopulmonary bypass (CPB) treatment. Thus, we sought to add our experience with this means of support as a bridge-to-recovery or to-decision. This retrospective single-center study analyzes the outcome of 11 children (median 23 months, minimum-maximum 3 months-6.5 years) who experienced drowning and subsequent cardiopulmonary resuscitation (CPR) between 2005 and 2016 and who were supported by veno-arterial extracorporeal membrane oxygenation (ECMO), CPB, or first CPB then ECMO. All but one incident took place in sweet water. Submersion time ranged between 10 and 50 minutes (median 23 minutes), water temperature between 2°C and 28°C (median 14°C), and body core temperature upon arrival in the emergency department between 20°C and 34°C (median 25°C). Nine patients underwent ongoing CPR from the scene until ECMO or CPB initiation in the operating room. The duration of ECMO or CPB before successful weaning/therapy withdrawal ranged between 2 and 322 hours (median 19 hours). A total of four patients (36%) survived neurologically mildly or not affected after 4 years of follow-up. The data indicate that survival is likely related to a shorter submersion time and lower water temperature. Resuscitation of pediatric patients after drowning has a poor outcome. However, ECMO or CPB might promote recovery in selected cases or serve as a bridge-to-decision tool.

Quantifying the Reduction in Microcirculation Perfusion After Extracorporeal Circulation

Extracorporeal circulation (ECC) is utilized in patients in critical care undergoing procedures such as extracorporeal membrane oxygenation or cardiopulmonary bypass. While most of these procedures are used to take over function of critical organs and provide oxygen to the organism, there is a lack of quantitative models established microcirculatory changes resulting from volume redistribution and changes in vascular pressure during and post ECC. To address this problem, we have combined an intravital microscopy model using the hamster dorsal window model with a custom ECC setup. Briefly, the customized ECC setup drains blood from the left jugular vein and reinfusing into the right carotid artery using a peristaltic pump. The pump is primed with either lactate ringers (LR), polymerized human hemoglobin (PolyhHb, concentration of 10 g/dL), or polymerized human methemoglobin (PolyhMetHb). Flow rate is gradually increased up to 15% of the animal's cardiac output (CO), maintained for 90 minutes, and then gradually decreased. Systemic parameters of pressure (MAP), heart rate (HR), and blood chemistry are monitored during the study. Microcirculatory measures of diameter, velocity, and flow are taken in the dorsal window model. Microcirculatory distribution of oxygen saturation is assessed using hyperspectral imaging. All the aforementioned measurements were taken at baseline, 0 hours, 2 hours, and 24 hours post ECC. After the 24 hour time point, tissues, plasma and urine were taken to assess markers of inflammation, organ function and injury, and hemoglobin and iron toxicity. Preliminary results indicate that arterioles show a markedly decreased diameter and velocity, and consequently blood flow, and venules show an increase in diameters with a drastic decrease in blood velocity. We project that decreases in MAP and HR along with respiratory acidosis will rectify by the 24 hr time point. We project that the LR group will have the worst microcirculatory flow due to the lack of proteins and low viscosity, followed by the PolyhMethb due to its high viscosity, but no oxygen carrying capacity, and the PolyhHb having the best flow due to the high viscosity and the ability to capture and carry oxygen. We expect that these flow parameters and decreased distribution of oxygen in the microcirculation will increase post-ECC, but will still be statistically significant at the 24 hour as compared to the baseline measurements. ECC redistributes blood flow and changes pressure redistribution due to the ECC circuit and pump, which cause changes in myogenic, metabolic, and endothelial mechanisms in smaller vessels in the microcirculation, affecting blood volume to organs and tissues. These studies will further our understanding of ECC impacts on the microcirculation and increase the success rate of these procedures.

Pediatric Extracorporeal Cardiopulmonary Resuscitation ELSO Guidelines.

Pediatric Extracorporeal Cardiopulmonary Resuscitation ELSO Guidelines.

Establishment of a novel miniature veno-venous extracorporeal membrane oxygenation model in the rat.

Recently, veno-venous extracorporeal membrane oxygenation (V-V ECMO) has been commonly used in the world to support patients with severe respiratory failure. However, V-V ECMO is a new technology compared to veno-arterial extracorporeal membrane oxygenation and cardiopulmonary bypass, and there are few reports of basic research. Although continuing research is desired, clinical research that standardizes conditions such as patients' background characteristics is difficult. The purpose of this study was to establish a simple and stably maintainable miniature V-V ECMO model to study the mechanisms of the biological reactions in circulation during V-V ECMO. The V-V ECMO system consisted of an original miniature membrane oxygenator, polyvinyl chloride tubing line, and roller pump. The priming volume of this system was only 8mL. Polyethylene tubing was used to cannulate the right femoral vein as the venous return cannula for the V-V ECMO system. A 16-G cannula was passed through the right internal jugular vein and advanced into the right atrium as the conduit for venous uptake. The animals were divided into 2 groups: SHAM group and V-V ECMO group. V-V ECMO was initiated and maintained at 50-60mL/kg/min, and oxygen was added into the oxygenator during V-V ECMO at a concentration of 100% (pump flow:oxygen=1:10). Blood pressure was measured continuously, and blood cells were measured by blood collection. During V-V ECMO, the blood pressure and hemodilution rate were maintained around 80 mmHg and 20%, respectively. Hb was kept at >10g/dL, and V-V ECMO could be maintained without blood transfusion. It was possible to confirm oxygenation of and carbon dioxide removal from the blood. Likewise, the pH was adequately maintained. There were no problems with this miniature V-V ECMO system, and extracorporeal circulation progressed safely. In this study, a novel miniature V-V ECMO model was established in the rat. A miniature V-V ECMO model appears to be very useful for studying the mechanisms of the biological reactions during V-V ECMO and to perform basic studies of circulation assist devices.

Frequency of Thrombocytopenia and Heparin-Induced Thrombocytopenia in Patients Receiving Extracorporeal Membrane Oxygenation Compared With Cardiopulmonary Bypass and the Limited Sensitivity of Pretest Probability Score.

To ascertain: 1) the frequency of thrombocytopenia and heparin-induced thrombocytopenia; 2) positive predictive value of the Pretest Probability Score in identifying heparin-induced thrombocytopenia; and 3) clinical outcome of heparin-induced thrombocytopenia in adult patients receiving venovenous- or venoarterial-extracorporeal membrane oxygenation, compared with cardiopulmonary bypass. A single-center, retrospective, observational cohort study from January 2016 to April 2018. Tertiary referral center for cardiac and respiratory failure. Patients who received extracorporeal membrane oxygenation for more than 48 hours or had cardiopulmonary bypass during specified period. None. Clinical and laboratory data were collected retrospectively. Pretest Probability Score and heparin-induced thrombocytopenia testing results were collected prospectively. Mean age (± SD) of the extracorporeal membrane oxygenation and cardiopulmonary bypass cohorts was 45.4 (± 15.6) and 64.9 (± 13), respectively (p < 0.00001). Median duration of cardiopulmonary bypass was 4.6 hours (2-16.5 hr) compared with 170.4 hours (70-1,008 hr) on extracorporeal membrane oxygenation. Moderate and severe thrombocytopenia were more common in extracorporeal membrane oxygenation compared with cardiopulmonary bypass throughout (p < 0.0001). Thrombocytopenia increased in cardiopulmonary bypass patients on day 2 but was normal in 83% compared with 42.3% of extracorporeal membrane oxygenation patients at day 10. Patients on extracorporeal membrane oxygenation also followed a similar pattern of platelet recovery following cessation of extracorporeal membrane oxygenation. The frequency of heparin-induced thrombocytopenia in extracorporeal membrane oxygenation and cardiopulmonary bypass were 6.4% (19/298) and 0.6% (18/2,998), respectively (p < 0.0001). There was no difference in prevalence of heparin-induced thrombocytopenia in patients on venovenous-extracorporeal membrane oxygenation (8/156, 5.1%) versus venoarterial-extracorporeal membrane oxygenation (11/142, 7.7%) (p = 0.47). The positive predictive value of the Pretest Probability Score in identifying heparin-induced thrombocytopenia in patients post cardiopulmonary bypass and on extracorporeal membrane oxygenation was 56.25% (18/32) and 25% (15/60), respectively. Mortality was not different with (6/19, 31.6%) or without (89/279, 32.2%) heparin-induced thrombocytopenia in patients on extracorporeal membrane oxygenation (p = 0.79). Thrombocytopenia is already common at extracorporeal membrane oxygenation initiation. Heparin-induced thrombocytopenia is more frequent in both venovenous- and venoarterial-extracorporeal membrane oxygenation compared with cardiopulmonary bypass. Positive predictive value of Pretest Probability Score in identifying heparin-induced thrombocytopenia was lower in extracorporeal membrane oxygenation patients. Heparin-induced thrombocytopenia had no effect on mortality.

Comparing the Use of Extracorporeal Membrane Oxygenation and Cardiopulmonary Bypass in Lung Transplantation

The method of cardiorespiratory support used during lung transplantation (LTx) has been debated. This study serves to compare survival after LTx in patients who received support from either extracorporeal membrane oxygenation (ECMO) or cardiopulmonary bypass (CPB). We studied 565 LTx performed at a single institution between March 2012 and June 2019. Concomitant cardiac procedures were excluded. 118 underwent CPB, 49 underwent ECMO, and 398 were considered "off-pump", as they received neither support. Comparisons between groups were performed using Chi-squared or ANOVA test. All significant variables from univariate analysis were included in a Cox regression analysis. Survival was assessed by Kaplan-Meier curve and compared by log rank test. P-values <0.05 were considered statistically significant. There was marginal survival difference (p =0.057) between the CPB, ECMO, and "off-pump" groups when analyzed together. When compared to the "off-pump" group in a Cox regression analysis, CPB (RR. 1.52, 95% CI: 0.99-2.31, p=0.054) and ECMO (RR. 1.71, 95% CI: 0.96-3.04, p=0.070) had borderline significant negative impact on survival. When compared amongst the three support groups, analysis of variances and Chi-squared tests showed no differences in recipient sex (p=0.089), race (p=0.42), donor age (p=0.69), donor type (brain death or donation after cardiac death) (p=0.59) and induction (p=0.38). The "off-pump" group was significantly older (p<0.001), had lower lung allocation scores (p=0.001) and had significantly more male donors (p=0.0084). The CPB group had a significantly higher number of double lung transplants (p<0.001). When accounting for these variables individually, Cox regression analysis showed they had no significant impact on survival. This study demonstrates the borderline significance of CPB and ECMO impact on survival and warrants further exploration into the question of proper cardiorespiratory support in LTx.