Deep Hypothermic Cardiac Arrest Research Articles

Renal cell carcinoma with an “uncoiling” tumor thrombus: intraoperative shift from level III to level IV

BackgroundThe gold standard treatment for renal cell carcinoma (RCC) with tumor thrombus (TT) is complete surgical excision. The surgery is complex and challenging to the surgeon, especially with large tumor thrombus extending into the inferior vena cava (IVC) and right atrium. Traditionally, these difficult cases required the use of cardiopulmonary bypass (CPB) with or without deep hypothermic cardiac arrest, but in recent years, different surgical techniques derived from the field of liver transplantation have been used in efforts to avoid CPB.Case presentationWe present a case of RCC with TT level IIIc (extending above major hepatic veins) that “uncoiled” intraoperatively into the right atrium after division of the IVC ligament, transforming into a level IV TT. Despite the new TT extension, the surgery was successfully completed exclusively through an abdominal approach without CPB and while using intraoperative transesophageal echocardiography (TEE) monitoring and a cardiothoracic team standby.ConclusionsThis case highlights the need for a multidisciplinary approach and the utility of intraoperative continous TEE monitoring which helped to visualize the change of the TT venous extension, allowing the surgical teamto modify their surgical approach as needed avoiding a catastrophic event.

Ascending Aortic Pseudostenosis following the Classic Bentall Inclusion Technique

We present the case of a 52-year-old with a history of aortic valve replacement and replacement of the ascending aorta with the graft inclusion technique presenting with dizziness and collapse. Computed tomography and coronary angiography revealed pseudoaneurysm formation at the anastomotic site causing aortic pseudostenosis. Due to severe calcification of the graft inclusion surrounding the ascending aorta, we performed a redo ascending aortic replacement using a two-circuit cardiopulmonary bypass to avoid deep hypothermic cardiac arrest.

Management of Wilms’ Tumor with Cavoatrial Extension Using Deep Hypothermic Cardiac Arrest and Selective Antegrade Cerebral Perfusion

ABSTRACT Wilms’ tumor is one of the most common genitourinary malignancies in children. It may be associated with extension of the tumor in the inferior vena cava (IVC) (4%–8%) and right atrium (1%–3%) of cases. In such a scenario, management of cases is further challenging and involves a multidisciplinary approach with medical and surgical specialties, including pediatric cardiac surgery involvement. We present a case of successful management of Wilms’ tumor involving the IVC, right atrium, and hepatic veins where we achieved synchronous surgical resection of both renal and vascular extension. Case management involved anticipated complications involving temperature management, fluid balance, and hemodynamic fluctuation due to intermittent IVC compression, bleeding, arrhythmias, complications involving deep hypothermic cardiac arrest and selective antegrade cerebral perfusion and possibility of tumor embolism.

Management of Locally Advanced Renal Cell Carcinoma

Renal cell carcinoma (RCC) has a natural tendency to invade the venous system with formation of a venous tumor thrombus in the renal vein, which can extend proximally into the inferior vena cava (IVC) and in some cases into the right atrium. The presence of venous involvement significantly worsens prognosis. Despite recent advances in systemic therapies, surgery remains the most effective method of treatment and in the case of complete removal of all tumor, it provides satisfactory long-term survival and must be attempted whenever possible. Several surgical techniques have been proposed, but all are associated with a high rate of perioperative complications and mortality. Minimally invasive approaches are mainly applicable for less extended IVC thrombi, while open surgery remains the gold standard for this category of patients. Most IVC thrombi can be managed without use of circulatory support by using different methods of IVC control depending on the thrombus level. However, use of cardiac bypass with or without deep hypothermic cardiac arrest is indicated in some patients with bulky intraatrial tumor thombi. In select patients presenting with IVC tumor thrombus and synchronous distant metastases, cytoreductive nephrectomy with IVC tumor thrombectomy may be considered with or without neoadjuvant systemic therapy. Surgery for RCC with venous thrombus is complex and requires experienced multidisciplinary surgical, anesthesia, and critical care teams at high-volume centers to achieve the best outcomes.

Management Of Intra-luminal IVC Tumor Extending Into The Heart

Several intra-abdominal malignancies have been associated with intravascular tumor thrombus extending into the inferior vena cava (IVC). A level IV tumor extension, defined as a tumor extending up to the level of the right atrium, poses a significant management challenge. The objective of the study is to describe the technique of deep hypothermic cardiac arrest (DHCA) and cardiopulmonary bypass (CPB) in the management of such tumor extensions.

Functional recovery after accidental deep hypothermic cardiac arrest: Comparison of different cardiopulmonary bypass rewarming strategies.

Introduction: Using a porcine model of accidental immersion hypothermia and hypothermic cardiac arrest (HCA), the aim of the present study was to compare effects of different rewarming strategies on CPB on need for vascular fluid supply, level of cardiac restitution, and cerebral metabolism and pressures. Materials and Methods: Totally sixteen healthy, anesthetized castrated male pigs were immersion cooled to 20°C to induce HCA, maintained for 75 min and then randomized into two groups: 1) animals receiving CPB rewarming to 30°C followed by immersion rewarming to 36°C (CPB30, n = 8), or 2) animals receiving CPB rewarming to 36°C (CPB36, n = 8). Measurements of cerebral metabolism were collected using a microdialysis catheter. After rewarming to 36°C, surviving animals in both groups were further warmed by immersion to 38°C and observed for 2 h. Results: Survival rate at 2 h after rewarming was 5 out of 8 animals in the CPB30 group, and 8 out of 8 in the CPB36 group. All surviving animals displayed significant acute cardiac dysfunction irrespective of rewarming method. Differences between groups in CPB exposure time or rewarming rate created no differences in need for vascular volume supply, in variables of cerebral metabolism, or in cerebral pressures and blood flow. Conclusion: As 3 out of 8 animals did not survive weaning from CPB at 30°C, early weaning gave no advantages over weaning at 36°C. Further, in surviving animals, the results showed no differences between groups in the need for vascular volume replacement, nor any differences in cerebral blood flow or pressures. Most prominent, after weaning from CPB, was the existence of acute cardiac failure which was responsible for the inability to create an adequate perfusion irrespective of rewarming strategy.

Cooling to Hypothermic Circulatory Arrest by Immersion vs. Cardiopulmonary Bypass (CPB): Worse Outcome After Rewarming in Immersion Cooled Pigs.

IntroductionCooling by cardiopulmonary bypass (CPB) to deep hypothermic cardiac arrest (HCA) for cardiac surgical interventions, followed by CPB-rewarming is performed on a routine basis with relatively low mortality. In contrast, victims of deep accidental hypothermia rewarmed with CPB generally have a much worse prognosis. Thus, we have developed an intact pig model to compare effects on perfusion pressures and global oxygen delivery (DO2) during immersion cooling versus cooling by CPB. Further, we compared the effects of CPB-rewarming between groups, to restitute cardiovascular function, brain blood flow, and brain metabolism.Materials and MethodsTotal sixteen healthy, anesthetized juvenile (2–3 months) castrated male pigs were randomized in a prospective, open placebo-controlled experimental study to immersion cooling (IMMc, n = 8), or cooling by CPB (CPBc, n = 8). After 75 minutes of deep HCA in both groups, pigs were rewarmed by CPB. After weaning from CPB surviving animals were observed for 2 h before euthanasia.ResultsSurvival rates at 2 h after completed rewarming were 4 out of 8 in the IMMc group, and 8 out of 8 in the CPBc group. Compared with the CPBc-group, IMMc animals showed significant reduction in DO2, mean arterial pressure (MAP), cerebral perfusion pressure, and blood flow during cooling below 25°C as well as after weaning from CPB after rewarming. After rewarming, brain blood flow returned to control in CPBc animals only, and brain micro dialysate-data showed a significantly increase in the lactate/pyruvate ratio in IMMc vs. CPBc animals.ConclusionOur data indicate that, although global O2 consumption was independent of DO2, regional ischemic damage may have taken place during cooling in the brain of IMMc animals below 25°C. The need for prolonged extracorporeal membrane oxygenation (ECMO) should be considered in all victims of accidental hypothermic arrest that cannot be weaned from CPB immediately after rewarming.

Evaluation of Seizure Risk in Infants After Cardiopulmonary Bypass in the Absence of Deep Hypothermic Cardiac Arrest.

BackgroundGuidelines recommend evaluation for electrographic seizures in neonates and children at risk, including after cardiopulmonary bypass (CPB). Although initial research using screening electroencephalograms (EEGs) in infants after CPB found a 21% seizure incidence, more recent work reports seizure incidences ranging 3–12%. Deep hypothermic cardiac arrest was associated with increased seizure risk in prior reports but is uncommon at our institution and less widely used in contemporary practice. This study seeks to establish the incidence of seizures among infants following CPB in the absence of deep hypothermic cardiac arrest and to identify additional risk factors for seizures via a prediction model.MethodsA retrospective chart review was completed of all consecutive infants ≤ 3 months who received screening EEG following CPB at a single center within a 2-year period during 2017–2019. Clinical and laboratory data were collected from the perioperative period. A prediction model for seizure risk was fit using a random forest algorithm, and receiver operator characteristics were assessed to classify predictions. Fisher’s exact test and the logrank test were used to evaluate associations between clinical outcomes and EEG seizures.ResultsA total of 112 infants were included. Seizure incidence was 10.7%. Median time to first seizure was 28.1 h (interquartile range 18.9–32.2 h). The most important factors in predicting seizure risk from the random forest analysis included postoperative neuromuscular blockade, prematurity, delayed sternal closure, bypass time, and critical illness preoperatively. When variables captured during the EEG recording were included, abnormal postoperative neuroimaging and peak lactate were also highly predictive. Overall model accuracy was 90.2%; accounting for class imbalance, the model had excellent sensitivity and specificity (1.00 and 0.89, respectively).ConclusionsSeizure incidence was similar to recent estimates even in the absence of deep hypothermic cardiac arrest. By employing random forest analysis, we were able to identify novel risk factors for postoperative seizure in this population and generate a robust model of seizure risk. Further work to validate our model in an external population is needed.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12028-021-01313-1.

Altered metabolic and inflammatory transcriptomics after cardiac surgery in neonates with congenital heart disease

The study examines the whole blood transcriptome profile before and after cardiopulmonary bypass (CPB) in neonates with hypoplastic left heart syndrome (HLHS), a severe form of congenital heart disease, that can develop low cardiac output syndrome (LCOS). Whole blood mRNA transcriptome profiles of 13 neonates with HLHS before and after their first palliative surgery were analyzed to determine differentially expressed genes and pathways. The median age and weight at surgery were 4 days and 3.2 kg, respectively. Of the 13 patients, 8 developed LCOS. There was no significant difference between CPB, aortic cross clamp, deep hypothermic cardiac arrest times between patients that develop LCOS and those that do not. Upon comparing differential gene expression profiles between patients that develop LCOS and those that do not in pre-operative samples, 1 gene was up-regulated and 13 were down regulated. In the post-operative samples, 4 genes were up-regulated, and 4 genes were down regulated when patients that develop LCOS were compared to those that do not. When comparing post-operative samples to pre-operative samples in the patients that do not develop LCOS, 1484 genes were up-regulated, and 1388 genes were down regulated; while patients that developed LCOS had 2423 up-regulated genes, and 2414 down regulated genes for the same pre to post-operative comparison. Pathway analysis revealed differential regulation of inflammatory pathways (IL signaling, PDGF, NOTCH1, NGF, GPCR) and metabolic pathways (heme metabolism, oxidative phosphorylation, protein metabolism including amino acid and derivatives, fatty acid metabolism, TCA cycle and respiratory electron transport chain). By identifying altered transcriptome profiles related to inflammation and metabolism in neonates with HLHS who develop LCOS after CPB, this study opens for exploration novel pathways and potential therapeutic targets to improve outcomes in this high-risk population.

Continuous EEG for Seizure Detection in Neonates after Cardiac Bypass without Deep Hypothermic Cardiac Arrest (2386)

Continuous EEG for Seizure Detection in Neonates after Cardiac Bypass without Deep Hypothermic Cardiac Arrest (2386)

Selective lower body perfusion during aortic arch surgery in neonates and small children.

Introduction:Aortic arch reconstruction surgery represents a challenge for the medical personnel involved in treatment. Along the years, the perfusion strategies for aortic arch reconstruction have evolved from deep hypothermic cardiac arrest to antegrade cerebral perfusion with moderate hypothermia, and recently to a combined cerebral and lower body perfusion with moderate hypothermia. To achieve a lower body perfusion, several cannulation strategies have been described. In this study, we investigated the feasibility of utilizing an arterial sheath introduced in the femoral artery to achieve an effective lower body perfusion.Methods:We included patients who underwent an aortic arch reconstruction surgery with a lower body perfusion, from January 2017 to June 2019. To achieve a lower body perfusion, a three-way stopcock was connected to the arterial line, where one end was connected to the central cannulation for cerebral perfusion and the other to an arterial sheath that was introduced through the femoral artery. A total of 25 patients were included. Peri- and postoperative lactate and creatinine levels and signs of malperfusion were recorded.Results:During the reperfusion phase, after selective perfusion ended none of the patients showed a significant increase in lactate, creatinine, and liver enzyme levels. After 24 hours, there were no signs of an acute kidney injury, femoral vessel injury, or limb malperfusion.Conclusion:These findings show that a sufficient lower body perfusion through an arterial sheath placed in the femoral artery for aortic arch reconstruction can be achieved. This approach caused no complications related to the arterial sheath during the early postoperative period and is an easy way to maintain perfusion of systemic organs.

Abstract 103: Rewarming Speed Affects Cardiopulmonary and Neurological Functions After Deep Hypothermic Cardiac Arrest

Introduction: The optimal rewarming rate from accidental or induced deep hypothermia is still unknown. Fast extracorporeal rewarming by extracorporeal circulation has been associated with cardiac dysfunction, pulmonary edema and poor neurologic outcome. Hypothesis: This study investigates whether the speed of rewarming after deep hypothermic cardiac arrest has neurological and cardiopulmonary effects. Methods: Thirty male Sprague-Dawley adult rats (450-550g) were rapidly cooled (ice packs) until 15°C core body temperature. Deep hypothermic cardiac arrest was maintained for 60 min. Thereafter rats were randomised to receive slow (90 minutes) or fast (30 minutes) rewarming by cardiopulmonary bypass to a target temperature of 35°C. After 90 minutes of reperfusion all animals underwent hemodynamic assessment by biventricular pressure-volume analysis, brain MRI and heart, lungs and brain were collected. Results: Slow rewarming preserved cardiac systolic and diastolic functions, ventricular arterial coupling and endothelium dependent relaxation. Lung edema was attenuated after slow rewarming. Cardimyocytes pro-survival kinases ERK and Akt activation were significantly higher in the slow rewarming group. MRI demonstrated enhancement of cerebral blood flow and reduction of cerebral edema after slow rewarming. Neurologic inflammatory response measured by IL-6, ICAM-1, CCL5 and TNF-α expression was significantly decreased in the slow rewarming group. Oxidative stress assessed by malondialdehyde was significantly reduced after slow rewarming. Conclusion: Slow rewarming by extracorporeal circulation after deep hypothermic cardiac arrest might improve systolic and diastolic function, preserve ventricular-arterial coupling, attenuate cerebral perfusion impairment and reduce neuronal damage.

Extracorporeal rewarming from experimental hypothermia: Effects of hydroxyethyl starch versus saline priming on fluid balance and blood flow distribution.

What is the central question of this study? Mortality in accidental hypothermia patients rewarmed by extracorporeal circulation remains high. Knowledge concerning optimal fluid additions for extracorporeal rewarming is lacking, with no apparent consensus. Does colloid versus crystalloid priming have different effects on fluid balance and blood flow distribution during extracorporeal rewarming? What is the main finding and its importance? In our rat model of extracorporeal rewarming from hypothermic cardiac arrest, hydroxyethyl starch generates less tissue oedema and increases circulating blood volume and organ blood flow, compared with saline. The composition of fluid additions appears to be important during extracorporeal rewarming from hypothermia. Rewarming by extracorporeal circulation (ECC) is the recommended treatment for accidental hypothermia patients with cardiac instability. Hypothermia, along with initiation of ECC, introduces major changes in fluid homeostasis and blood flow. Scientific data to recommend best practice use of ECC for rewarming these patients is lacking, and no current guidelines exist concerning the choice of priming fluid for the extracorporeal circuit. The primary aim of this study was to compare the effects of different fluid protocols on fluid balance and blood flow distribution during rewarming from deep hypothermic cardiac arrest. Sixteen anaesthetized rats were cooled to deep hypothermic cardiac arrest and rewarmed by ECC. During cooling, rats were equally randomized into two groups: an extracorporeal circuit primed with saline or primed with hydroxyethyl starch (HES). Calculations of plasma volume (PV), circulating blood volume (CBV), organ blood flow, total tissue water content, global O2 delivery and consumption were made. During and after rewarming, the pump flow rate, mean arterial pressure, PV and CBV were significantly higher in HES-treated compared with saline-treated rats. After rewarming, the HES group had significantly increased global O2 delivery and blood flow to the brain and kidneys compared with the saline group. Rats in the saline group demonstrated a significantly higher total tissue water content in the kidneys, skeletal muscle and lung. Compared with crystalloid priming, the use of an iso-oncotic colloid prime generates less tissue oedema and increases PV, CBV and organ blood flow during ECC rewarming. The composition of fluid additions appears to be an important factor during ECC rewarming from hypothermia.

PD24-12 COMPARISON BETWEEN LIVER DEROTATION WITH PRINGLE MANOEUVRE AND CARDIOPULMONARY BYPASS WITH DEEP-HYPOTHERMIC CARDIAC ARREST FOR KIDNEY CANCER WITH MAYO III TUMOR THROMBUS: INTRA-, PERI- AND POSTOPERATIVE OUTCOMES

PD24-12 COMPARISON BETWEEN LIVER DEROTATION WITH PRINGLE MANOEUVRE AND CARDIOPULMONARY BYPASS WITH DEEP-HYPOTHERMIC CARDIAC ARREST FOR KIDNEY CANCER WITH MAYO III TUMOR THROMBUS: INTRA-, PERI- AND POSTOPERATIVE OUTCOMES

End-to-side anastomosis for interrupted aortic arch in neonates and infants

Objective: To review the early and mid-term results of end-to-side anastomosis technique for interrupted aortic arch in neonates and infants. Methods: Clinic data of 46 patients were diagnosed as interrupted aortic arch in Department of Cardiac Surgery, Guangzhou Women and Children's Medical Center between January 2010 and December 2016 were analyzed retrospectively. Twenty-six cases were neonates. The median age underwent surgery was 23 days (range: 2 days to 8 years). Anatomical subtypes included 36 cases of type A and 10 cases of type B. There was no type C case. The reconstruction of the aortic arch was completed by an extended end-to-side anastomosis technique between the descending aorta and the undersurface of the proximal aortic arch. In 42 patients, all with intracardiac anomalies, had concomitant complete repair of intracardiac anomalies through a median sternotomy. The remaining 4 patients, all without intracardiac anomalies, an end-to-side anastomosis was constructed through a left thoracotomy. During follow-up, aortic arch recurrent obstruction, left ventricular outflow tract obstruction (LVOTO) and tracheal stenosis were focused. Results: There were 3 surgical deaths, with amortality rate of 6.5%. The remaining 43 patients survived after surgery. In 39 of these patients, deep hypothermic cardiac arrest (DHCA) strategy was used for brain protection, and the mean time of DHCA was (16±3) minutes. Eight patients underwent delayed sternal closure. The mean mechanical ventilation time and ICU stay time were (3.4±1.6) days (range: 2 to 12 days) and (6.4±2.7) days (range: 3 to 16 days) respectively. In 16 patients, all with tracheal or bronchial stenosis before surgery, mechanical ventilation was successfully evacuated, and no new airway stenosis occurred. There was no residual pressure difference between upper and lower extremity arterial blood pressure at discharge. Echocardiography showed normal arterial blood flow velocity in aortic arch. At a mean follow-up of (36.2±18.9) months (range: 6 months to 7 years), there were two patients lost and one late date. Four patients developed a recurrent stenosis at the aortic arch, of which two were severe, and the other two were mild. In 2 patients, both with mild LVOTO before surgery, no significant increase in the degree of obstruction was found during the follow-up. Two patients developed new mild to moderate LVOTO without clinical symptoms, and continued to follow up. In all patients, the tracheal or bronchial stenosis were extenuated, and there was no new progressive airway stenosis by regular bronchoscopy. Conclusions: The end-to-side anastomosis technique for the reconstruction of the aortic arch achieved excellent early and mid-term results in neonates and infants suffered from interrupted aortic arch. Reducing the anastomotic tension by extensive mobilization is the key to prevent postoperative early complications and late recurrent arch obstruction.

Deep hypothermia therapy attenuates LPS-induced microglia neuroinflammation via the STAT3 pathway

Deep hypothermia therapy (HT) is a standard method for neuroprotection during complex pediatric cardiac surgery involving extracorporeal circulation and deep hypothermic cardiac arrest. The procedure, however, can provoke systemic inflammatory response syndrome (SIRS), one of the most severe side effects associated with pediatric cardiac surgery. To date, the cellular inflammatory mechanisms induced by deep HT remain to be elucidated. Therefore, we investigated the effects of deep HT (17°C) and rewarming on the inflammatory response in lipopolysaccharide (LPS) stimulated BV-2 murine microglia. Additionally, we also investigated the application of Stattic, a signal transducer and activator of transcription 3 (STAT3) activation inhibitor, as an alternative to physical cooling to attenuate the LPS-induced inflammatory response.Deep HT had no cytotoxic effect but attenuated microglia migration. IκBα degradation was delayed by deep HT resulting in the attenuation of pNF-κB p65 migration into the nucleus and significant decreases in pro-inflammatory IL-6, TNF-α, and MCP-1 expressions and secretions, as well as decreased anti-inflammatory IL-10 and SOCS3 expressions. Additionally, pStat3 was significantly down regulated under deep hypothermic conditions, also corresponding with the significant reduction in IL-6 and TNF-α expressions. Similar to the effects of HT, the application of Stattic under normothermic conditions resulted in significantly reduced IL-6 and TNF-α expressions. Moreover, attenuation of the inflammatory response resulted in decreased apoptosis in a direct co-culture of microglia and neurons.HT reduces the inflammatory response in LPS-stimulated BV-2 microglial cells, alluding to a possible mechanism of therapeutic hypothermia-induced neuroprotection. In the future, attenuating the phospho-STAT3 pathway may lead to the development of a neuroprotectant with greater clinical efficacy.

Relationship Between Transfusion of Blood Products and the Incidence of Thrombotic Complications in Neonates and Infants Undergoing Cardiac Surgery

The authors hypothesized that transfusion of blood products in neonates and infants undergoing high-risk cardiac surgery in the absence of intraoperative coagulation monitoring increases the risk of thrombotic complications. Prospective observational study. Neonates and infants undergoing cardiac surgery at a tertiary pediatric center. Neonates weighing >2.5 kg and infants ≤12 months of age undergoing elective cardiac surgery with cardiopulmonary bypass were included in this prospective observational study. None. Demographic data, surgical characteristics, transfusion data, and coagulation parameters (thromboelastography and thromboelastometry) were collected. Logistic regression analysis was performed to identify potential determinants of postoperative thrombotic complications. Among the 138 neonates and infants included in the study, 12 (9%) developed a postoperative thrombotic complication. Unadjusted logistic regression analysis confirmed that the number and volume of blood products transfused were associated significantly with the increased incidence of thrombotic complication (odds ratio: 2.78, 95% confidence interval: 1.30-5.94, p = 0.008). This association persisted after adjustment for patient's age, the need for deep hypothermic cardiac arrest, and bypass time (odds ratio: 2.23, 95% confidence interval: 1.02-4.87, p = 0.044). The number of blood products transfused was associated with a significant increase in parameters of clot amplitudes measured at cardiac intensive care unit admission, while no difference was reported when measured after the administration of protamine. This prospective observational study reports a significant association between transfusion of blood products in neonates and young infants undergoing cardiac surgery and an increased incidence of thrombotic complications in the absence of intraoperative coagulation monitoring.

Thoracoabdominal aortic replacement for Crawford extent II aneurysm after thoracic endovascular aortic repair

The surgical treatment of Crawford extent II aneurysms after thoracic endovascular aortic repair (TEVAR) remains challenging, because of the need to remove the failed endograft and the complexity of the aortic reconstruction. We retrospectively reviewed our experience with surgical management of Crawford extent II aneurysms after TEVAR using thoracoabdominal aortic replacement (TAAR). Eleven patients (10 males, 1 female) with Crawford extent II aneurysm after TEVAR were treated with TAAR between August 2012 and May 2015. The indications included: diameter >5.0 cm; persistent pain; size increase >0.5 cm/year; and no suitable landing zone for re-TEVAR. Five patients underwent surgery under deep hypothermic cardiac arrest, two under mild hypothermic cardiopulmonary bypass, and four under direct aortic cross-clamping under normothermia. Two patients had Marfan syndrome. There were no in-hospital deaths. Continuous renal replacement therapy was required in three patients. One patient needed re-intubation, and two patients had prolonged intubation (>72 h). One patient sustained paraplegia after surgery but recovered during follow-up. Cerebrospinal fluid drainage were used in four patients (3 immediately in the operation room, and 1 in the intensive care unit when the patient suffered paraplegia). One patient died during follow-up. TAAR represents a feasible option for the treatment of Crawford extent II aneurysms after TEVAR, with acceptable surgical risks and favorable results.

Cardiopulmonary responses during the cooling and the extracorporeal life support rewarming phases in a porcine model of accidental deep hypothermic cardiac arrest

BackgroundThis study aimed to assess cardiac and pulmonary pathophysiological responses during cooling and extracorporeal life support (ECLS) rewarming in a porcine model of deep hypothermic cardiac arrest (DHCA). In addition, we evaluated whether providing a lower flow rate of ECLS during the rewarming phase might attenuate cardiopulmonary injuries.MethodsTwenty pigs were cannulated for ECLS, cooled until DHCA occurred and subjected to 30 min of cardiac arrest. In order to assess the physiological impact of ECLS on cardiac output we measured flow in the pulmonary artery using Doppler echocardiography as well as a modified thermodilution technique using the Swan-Ganz catheter (injection site in the right ventricle). The animals were randomized into two groups during rewarming: a group with a low blood flow rate of 1.5 L/min (LF group) and a group with a normal flow rate of 3.0 L/min (NF group). The ECLS temperature was adjusted to 5 °C above the central core. Cardiac output, hemodynamics and pulmonary function parameters were evaluated.ResultsDuring the cooling phase, cardiac output, heart rhythm and blood pressure decreased continuously. Pulmonary artery pressure tended to increase at 32 °C compared to the initial value (20.2 ± 1.7 mmHg vs. 29.1 ± 5.6 mmHg, p = 0.09). During rewarming, arterial blood pressure was higher in the NF than in the LF group at 20° and 25 °C (p = 0.003 and 0.05, respectively). After rewarming to 35 °C, cardiac output was 3.9 ± 0.5 L/min in the NF group vs. 2.7 ± 0.5 L/min in LF group (p = 0.06). At the end of rewarming under ECLS cardiac output was inversely proportional to the ECLS flow rate. Moreover, the ECLS flow rate did not significantly change pulmonary vascular resistance.DiscussionUsing a newly developed experimental model of DHCA treated by ECLS, we assessed the cardiac and pulmonary pathophysiological response during the cooling phase and the ECLS rewarming phase. Despite lower metabolic need during hypothermia, a low ECLS blood flow rate during rewarming did not improved cardiopulmonary injuries after rewarming.ConclusionA low ECLS flow rate during the rewarming phase did not attenuate pulmonary lesions, increased blood lactate level and tended to decrease cardiac output after rewarming. A normal ECLS flow rate did not increase pulmonary vascular resistance compared to a low flow rate. This experimental model on pigs contributes a number of pathophysiological findings relevant to the rewarming strategy for patients who have undergone accidental DHCA.

Deep Hypothermic Cardiac Arrest Treated by Extracorporeal Life Support in a Porcine Model: Does the Rewarming Method Matter?

Extracorporeal life support (ECLS) is the reference rewarming technique of accidental deep hypothermic cardiac arrest (DHCA). This study was designed to examine the impact of different rewarming blood flow rates and temperature setting of ECLS on cardiopulmonary lesions after DHCA in a porcine model of accidental hypothermia. Twenty-four pigs were cannulated for ECLS, cooled until DHCA occurred, and subjected to 30 minutes of cardiac arrest. During the rewarming phase, we compared a low blood flow rate of 1.5 L/min versus a high flow rate of 3.0 L/min as well as two-temperature-setting rewarming strategies: a temperature during ECLS adjusted to 5°C above the central core temperature versus 38°C maintained throughout the rewarming phase. Cardiac output, hemodynamics and pulmonary function parameters were evaluated. Biologic markers of ischemia-reperfusion injuries were analyzed at baseline and at the end of the experiment. DHCA occurred at 21.2 ± 2°C. There was a trend for better cardiac output in groups with high blood flow (p = 0.053), with no interaction between ECLS flow and temperature (p = 0.63), a trend toward lower pulmonary vascular resistance (PVR; p = 0.075) and a significant decrease in arterial PVR in groups with high blood flow (p = 0.013) with no interaction (p = 0.47 and p = 0.60 for PVR and arterial PVR, respectively). Serum interleukin-6, tumor necrosis factor-α, receptor for advanced glycation end products (RAGE), and neuron-specific enolase were significantly increased between baseline and endpoint. The increase in the serum RAGE concentration was higher in the 38°C rewarming temperature groups compared to 5°C above adjusted temperature. There were no other significant differences in biomarkers. We developed a porcine model of DHCA treated by ECLS. Our data suggest that cardiac output tended to improve with a high-flow-rate rewarming strategy while a high-temperature delta between core temperature and ECLS increased the RAGE markers of lung injury.