Normothermic Cardiopulmonary Bypass Research Articles

Can Cerebral Oximetry Near-Infrared Spectroscopy Strategy in Hypothermic Cardiopulmonary Bypass in Congenital Cardiac Surgery be Considered an Advanced Nursing Practice?

Background: The importance of cerebral perfusion during congenital cardiac surgery, especially after hypothermic cardiopulmonary bypass (CPB) strategy, has remained a debate. In this study, we evaluated the effect of mild hypothermic CPB strategy on cerebral oximetry near-infrared spectroscopy in congenital heart defects surgery. Methods: In a randomized prospective study, the pediatrics aged two months and six years with RACHS categories I-Ⅱ for congenital heart defects surgery were randomly divided into normothermic and mild hypothermic CPB groups. The NIRS was measured in all patients via the INVOS ™ cerebral oximetry system. The perfusion and anesthesia strategies during the study were followed as standard methods. A p-value below 0.05 is considered to be a significant level. Results: Regarding cerebral oximetry, the results showed no significant difference between normothermic and mild hypothermic CPB groups. Conclusion: It can be concluded that optimizing cerebral oxygen saturation monitoring during congenital cardiac surgery can improve patient outcomes as a protective strategy.

Normothermic cardiopulmonary bypass and beating heart surgery for renal cell cancer with tumor thrombus extension into inferior vena cava and right atrium: a less invasive strategy.

Management of renal cell carcinoma (RCC) with inferior vena cava (IVC) extension is one of the greatest challenges in urology. The gold standard treatment includes extracorporeal circulation and deep hypothermic circulatory arrest (DHCA). However, this surgical treatment has an impact on survival and prognosis. We aim to present a less invasive surgical approach for the treatment of level III and IV IVC thrombi in RCC. We identified all patients undergoing radical nephrectomy and thrombectomy at our Institution between 2016 and 2020. Patients with level IV thrombi were treated with a combined thoracic and abdominal procedure: beating heart surgery with normothermic cardiopulmonary bypass (CPB) was used for thrombus retrieval. Level III thrombi were approached exclusively through an abdominal access. We identified 12 patients treated with radical nephrectomy and thrombectomy among 243 patients undergoing radical nephrectomy for RCC. Mean age was 69.3 years, most patients were in T3c clinical stage, without lymph-node involvement (75%) and no metastases (66.7%); 58.3% of patients had Mayo III thrombus classification. Median intensive care unit stay was 2 days and total in-hospital stay 10.5 days. In-hospital mortality was 0%, with a 66.6% survival rate at 2 years. Beating heart surgery with normothermic CPB can be considered a less invasive method for radical resection of Mayo level IV IVC thrombi. This surgical approach is safe and feasible, with good in-hospital and short-term outcomes.

Early outcomes of experience warm surgery in children undergoing complete repair of tetralogy of Fallot in developing countries

ObjectivesWhile significant evidence supports the benefits of normothermic cardiopulmonary bypass (NCPB) over hypothermic techniques, many institutions in developing countries, including ours, continue to employ hypothermic methods. This study aimed to assess the early postoperative outcomes of normothermic cardiopulmonary bypass (NCPB) for complete surgical repair via the Tetralogy of Fallot (TOF) within our national context.MethodsWe conducted this study in the Pediatric Cardiac Intensive Care Unit (PCICU) at the University Children’s Hospital. One hundred patients who underwent complete TOF repair were enrolled and categorized into two groups: the normothermic group (n = 50, temperature 35–37 °C) and the moderate hypothermic group (n = 50, temperature 28–32 °C). We evaluated mortality, morbidity, and postoperative complications in the PCICU as outcome measures.ResultsThe demographic characteristics were similar between the two groups. However, the cardiopulmonary bypass (CPB) time and aortic cross-clamp (ACC) time were notably longer in the hypothermic group. The study recorded seven deaths, yielding an overall mortality rate of 7%. No significant differences were observed between the two groups concerning mortality, morbidity, or postoperative complications in the PCICU.ConclusionsOur findings suggest that normothermic procedures, while not demonstrably effective, are safe for pediatric cardiac surgery. Further research is warranted to substantiate and endorse the adoption of this technique.

Use of the composite Y-shaped veno-venous bypass graft in coronary surgery

Introduction. This study was performed to assess the functional status of Y­shaped veno­venous bypass grafts in cases of lacking both arterial and venous material, as well as in patients with ascending aorta abnormalities, in order to perform the most adequate myocardial revascularisation. Material. The retrospective study performed in Scientific and Practical Center of Interventional Cardioangiology included 43 patients, who underwent surgery between 2017 and 2022. The main inclusion criterion for the study was coronary artery bypass grafting (CABG) with the use of Y­shaped venous conduits. The control bypass angiography was performed in average in 33 ± 8 months. All interventions were performed under normothermic cardiopulmonary bypass (CPB), and the average number of conduits per patient was 3.4. Results. Satisfactory functional status of the Y­shaped venous bypass grafts in the long­term (33 ± 8 months) period was observed in 86.1% of cases. At that, no cases of cerebrovascular accident were reported in the postoperative period, as well as no sternal infections in patients with insulin­dependent diabetes mellitus, and only one patient out of 20 patients with severe lower limb ischaemia had wound infection of the lower extremity (5%). Conclusions. Y­shaped veno­venous bypass grafts demonstrated quite acceptable long­term functional results in patients with ascending aorta abnormalities or conduit deficiency and they can be used to achieve the most adequate myocardial revascularisation. Keywords: CABG, Y­shaped bypass graft, venous conduit, aortic atheromatosis

Normothermic frozen elephant trunk without circulatory arrest

We describe our technique for total aortic arch replacement with stenting of the descending thoracic aorta allowing normothermic cardiopulmonary bypass and avoiding hypothermic circulatory arrest.

Temperature management of intraoperative cardiopulmonary bypass in valve replacement surgery: a retrospective analysis of the impact on postoperative organ function.

This study aimed to systematically analyze the effects of cardiopulmonary bypass (CPB) at different temperatures on the function of different organs in patients after heart valve replacement and to investigate its safety and feasibility. The data of 275 heart valve replacement surgery patients who underwent static suction compound anesthesia under CPB between February 2018 and October 2019 were retrospectively analyzed and divided into normothermic CPB anesthesia group (group 0), shallow hypothermic CPB anesthesia group (group 1), medium hypothermic CPB anesthesia group (group 2), and deep hypothermic CPB anesthesia group (group 3) according to the different intraoperative CPB temperatures. The basic preoperative conditions, cardiac resuscitation, number of defibrillations, postoperative ICU stay, postoperative hospital stay, and postoperative evaluation of different organ functions, such as heart, lung, and kidney functions, were analyzed and studied in each group. The comparison of preoperative and postoperative pulmonary artery pressure and left ventricular internal diameter (LVD) was statistically significant in each group (p < 0.05), and the postoperative pulmonary function pressure was statistically significant in group 0 compared with groups 1 and 2 (p < 0.05). The preoperative glomerular filtration rate (eGFR) and the eGFR on the first postoperative day were statistically significant in all the groups (p < 0.05), and the eGFR on the first postoperative day in groups 1 and 2 were statistically significant (p < 0.05). The control of appropriate temperature during CPB was associated with the recovery of organ function in patients after valve replacement. Intravenous compound general anesthesia with superficial hypothermic CPB might be more beneficial in recovering cardiac, pulmonary, and renal functions.

Organ damage evaluation in a temperature-controlled circulatory arrest rat model

BackgroundDeep hypothermic circulatory arrest (DHCA) is commonly used in adult aortic surgery and pediatric complex congenital heart disease, and is associated with pathophysiological changes and postoperative complications. Here, a temperature-controlled circulatory arrest model in rats was established to study the suitable temperature of circulatory arrest by investigating the damage to body organs under different temperatures.MethodsThirty Sprague‒Dawley rats were randomly divided into 5 equal groups for DHCA experiments: I (15–20 °C), II (20–25 °C), III (25–30 °C), IV (normothermic cardiopulmonary bypass), and V (sham operation group). Blood gas analysis, homodynamic parameters, and intervals of cardiac recovery were measured at different time points in all groups. Morphological changes in intestinal tissue were observed under light and electron microscopes. Oxidative stress was measured by MPO activity, MDA, and SOD content. Tissue damage was confirmed by serum detection of ALT, AST, BUN, Cr, and LDH. To examine the inflammatory response, cytokines, including IL-1, IL-4, IL-10, IFN-γ, and TNF-α, were detected.ResultsThe extracorporeal circulation technique caused damage to the body; the degree of the damage caused by the circulatory arrest technique may be related to circulating temperature, with the least amount of damage occurring at 20–25 °C compared to 15–20 °C and 25–30 °C. Ischemia and hypoxia can cause intestinal tissue damage, which manifests primarily as a loss of the intestinal mucosal barrier. Ischemic intestinal damage caused by DHCA was not associated with inflammation.ConclusionThe study provides new insights into the pathophysiologic mechanisms of DHCA.

Enhanced recovery after minimally invasive heart valve surgery: Early and midterm outcomes

BackgroundAlthough the use of protocols for “enhanced recovery after surgery” (ERAS) have been associated with improved results in different surgical specialties, only a few data are available for ERAS in cardiac surgery. This study aimed to compare 30-day outcomes of patients undergoing ultra-fast-track minimally invasive valve surgery (UFT-MIVS) versus conventional MIVS (c-MIVS). MethodsThe key features of UFT-MIVS approach involves: 1) less invasive valve surgery techniques, 2) normothermic cardiopulmonary bypass management, 3) UFT-anesthesia with table extubation, 4) immediate rehabilitation therapy and patient-family contact. Five-hundred and seventy-six consecutive patients who underwent aortic or mitral MIVS were analyzed (2016–2020). Treatment selection bias (UFT-MIVS vs. c-MIVS) was addressed by the use of propensity score (PS) matching. After PS-matching 2 well-balanced groups of 152 patients each were created. ResultsIn the matched cohort, the overall 30-day mortality and stroke rates were 0.3% and 0.7%, respectively, with no difference between groups. UFT-MIVS resulted in lower rates of respiratory insufficiency and agitation/delirium compared with c-MIVS. Patients receiving UFT-MIVS were associated with significantly shorter intensive care unit length of stay and hospital stay. ConclusionsOur study confirms that MIVS is associated with excellent results in terms of early mortality and major postoperative complications rates. The implementation of UFT-MIVS protocol showed to be safe and was associated with improved clinical outcomes in regard to respiratory insufficiency, delirium and lengths of stay.

Reliability of different body temperature measurement sites during normothermic cardiac surgery.

Patients undergoing cardiac surgery can experience significant thermal changes during the perioperative period and, for that reason, it is essential to monitor temperatures with adequate accuracy and precision during cardiopulmonary bypass (CPB). The primary aim of the current study was to measure the discrepancies between temperatures at different body sites during normothermic or mild hypothermic CPB. 48 patients undergoing cardiac surgery participated in our study. Simultaneous temperatures were measured at nasopharynx, pulmonary artery, arterial outlet, venous inlet, forehead using a heat flux sensor, and urinary bladder at 5-min intervals throughout surgery. The Bland-Altman plot for repeated measures was used to assess concordance between methods. The duration of surgery was 360min (interquartile range (IQR) 300-412), while the median cross-clamp time was 135min (IQR 101-169). During the CPB time, the average difference between arterial outlet and nasopharyngeal temperature was -0.16°C (95% limits of agreement of ±0.93). The bias between arterial outlet and the venous inflow was 0.16°C and the 95% limits of agreement were -0.63 to 0.95°C. The Bland-Altman analysis showed an average difference between oxigenator arterial outlet and bladder probe of -0.62 (95% limits of agreement of ±1.3). The average difference between arterial outlet and Tcore™ temperatures was 0.08°C (95% limits of agreement of ±1.46). 25 patients (52.08%) presented nasopharyngeal temperatures higher than 37°C in the post-CPB period, but none of them exceeded 38°C. Perfusionists should be cautious when using the nasopharyngeal site as the only surrogate of brain temperature, even in normothermic cardiac surgery because the precision of measurements is not entirely adequate.

Safety of Normothermic Cardiopulmonary Bypass in Pediatric Cardiac Surgery: A System Review and Meta-Analysis.

Objectives: Hypothermic cardiopulmonary bypass (HCPB) has been used successfully in cardiac surgery for more than half a century, although adverse effects have been reported with its use. Many studies on temperature management during CPB published to date have shown that normothermic CPB (NCPB) provides more benefits to children undergoing cardiac surgery. The present meta-analysis investigated the effect of NCPB on clinical outcomes based on results of randomized controlled trials and observational studies on pediatric cardiac surgery.Methods: Databases such as PubMed, EMBASE, Cochrane Central Register of Controlled Trials, and Clinical Trials.gov were searched from inception to May 2021 to identify relevant studies published in English.Results: The present meta-analysis included 13 studies characterizing a total of 837 pediatric patients. The random effects model exhibited that the NCPB group had reduced revision for postoperative bleeding [odds ratio (OR): 0.11; 95% confidence interval (CI): 0.01–0.89; I2 = 0%, P = 0.04], serum lactate 2–4 h after CPB (mean difference: −0.60; 95% CI: −1.09 to −0.11; I2 = 82%, P = 0.02), serum creatinemia 24 h after CPB (mean difference: −2.73; 95% CI: −5.06 to −0.39; I2 = 83%, P = 0.02), serum creatinemia 48 h after CPB (mean difference: −2.08; 95% CI: −2.78 to −1.39; I2 = 0%, P < 0.05), CPB time (mean difference: −19.10, 95% CI: −32.03 to −6.18; I2 = 96%, P = 0.04), and major adverse events (OR: 0.37; 95% CI: 0.15–0.93; Z = 2.12, P = 0.03) after simple congenital surgery compared with the HCPB group.Conclusion: NCPB is as safe as HCPB in pediatric congenital heart surgery. Moreover, NCPB provides more advantages than HCPB in simple congenital heart surgery.

Strategies to Prevent Acute Kidney Injury after Pediatric Cardiac Surgery: A Network Meta-Analysis.

AKI is a common complication after pediatric cardiac surgery and has been associated with higher morbidity and mortality. We aimed to compare the efficacy of available pharmacologic and nonpharmacologic strategies to prevent AKI after pediatric cardiac surgery. PubMed/MEDLINE, Embase, Cochrane Controlled Trials Register, and reference lists of relevant articles were searched for randomized controlled trials from inception until August 2020. Random effects traditional pairwise, Bayesian network meta-analyses, and trial sequential analyses were performed. Twenty randomized controlled trials including 2339 patients and 11 preventive strategies met the eligibility criteria. No overall significant differences were observed compared with control for corticosteroids, fenoldopam, hydroxyethyl starch, or remote ischemic preconditioning in traditional pairwise meta-analysis. In contrast, trial sequential analysis suggested a 80% relative risk reduction with dexmedetomidine and evidence of <57% relative risk reduction with remote ischemic preconditioning. Nonetheless, the network meta-analysis was unable to demonstrate any significant differences among the examined treatments, including also acetaminophen, aminophylline, levosimendan, milrinone, and normothermic cardiopulmonary bypass. Surface under the cumulative ranking curve probabilities showed that milrinone (76%) was most likely to result in the lowest risk of AKI, followed by dexmedetomidine (70%), levosimendan (70%), aminophylline (59%), normothermic cardiopulmonary bypass (57%), and remote ischemic preconditioning (55%), although all showing important overlap. Current evidence from randomized controlled trials does not support the efficacy of most strategies to prevent AKI in the pediatric population, apart from limited evidence for dexmedetomidine and remote ischemic preconditioning.

Surgical Experience with Normothermic Cardiopulmonary Bypass- 3 Years of History: Retrospective Case Series of 50 Patients

Introduction: Numerous beneficial mechanisms have been linked to normothermic open cardiac surgical procedures. The objective of our research is the evaluation of the experience in the Hospital General de la Plaza de la Salud, after 50 cases, as a propitious moment to assume it as an option Pursues to nurture the debate with the evaluation of patients who underwent different open cardiac surgical procedures using normothermia. Materials and Methods: This is a prospective, case series study, which includes a sample of 50 patients who underwent normothermic open cardiac surgery requiring cardiopulmonary bypass from 2017 to 2021. Results: Of the sample, 30% (n=15) accounted for procedures involving aortic valve replacement on cardiopulmonary bypass, 42% (n=21) accounted for mitral valve replacement, and 28% (n=14) of case represented open coronary vessels interventions on cardiopulmonary bypass. The average age for such procedure was 49.6 years. An average of 83.5 minutes were spent on cardiopulmonary bypass. On average, patients underwent 64.8 minutes with clamped vessels. Average blood loss was quantified in milliliters for the three procedures and was reported for the 1st hour, 4th hour, and the 12th hour after procedure initiation as well as total quantified blood loss. The combined set of procedures represented a cumulative average of 272.3 mL of blood loss. Haemoglobin percent change for the cases included in the study were represented by an average change of -.002% for all procedures. On average, patients undergoing all procedures required 1.3 whole blood packets and 1.2 packets of fresh frozen plasma. Hospital stays, counted from the day of admission to the day of discharge, was another factor evaluated for the study. 8.2, 8.0 and 8.8 days represented the average hospital stay for patients undergoing aortic valve replacement, mitral valve replacement and coronary interventions respectively. Conclusion: Normothermia during cardiothoracic surgery that employed cardiopulmonary bypass is a safe and effective strategy.

Mild hypothermia versus normothermia in patients undergoing cardiac surgery

ObjectiveTemperature during cardiopulmonary bypass (CPB) for cardiac surgery has been controversial. The aim of the current study is to compare the outcomes for patients with mild hypothermia versus normothermic CPB temperatures. MethodsAll patients who underwent cardiac surgery with CPB and temperatures ≥32°C from 2011 to 2018 were included, which consisted of mild hypothermia (32°C-35°C) and normothermia (>35°C) cohorts. Propensity matching (1:1) was performed for risk adjustment. Primary outcomes included operative and long-term survival. Secondary outcomes included postoperative complications. ResultsA total of 6525 patients comprised 2 cohorts: mild hypothermia (32°C-35°C; n = 3148) versus normothermia (>35°C; n = 3377). Following adjustment for surgeon preference, there were 1601 propensity-matched patients who had similar baseline characteristics (standard mean difference, ≤0.10), including CPB time, crossclamp time, and intra-aortic balloon pump placement. Kaplan-Meier analysis showed no difference in long-term survival (82.6% vs 81.6%; P = .81). Over a median follow-up of 4.4 years, there were no differences in overall mortality (18.1% vs 18.1%; P = 1.1) or readmission (50.3% vs 48.3%; P = .2). Acute renal failure (3.7% vs 2.4%; P = .03) and intensive care unit hours (46.5 vs 45.1; P = .04) were significantly higher with hypothermia. There was no difference between cohorts for postoperative stroke (2.0% vs 2.0%; P = 1.0), reoperation (5.9% vs 6.0%; P = .9), or operative intra-aortic balloon pump placement (1.7% vs 1.8%; P = .9). ConclusionsPatients with mild hypothermia during CPB had increased postoperative renal failure and length of intensive care unit stay. Although there was no difference in long-term survival, mild hypothermia does not appear to offer patients appreciable benefits, compared with normothermia.

Effects of circulatory arrest and cardiopulmonary bypass on cerebral autoregulation in neonatal swine

BackgroundCerebral autoregulation mechanisms help maintain adequate cerebral blood flow (CBF) despite changes in cerebral perfusion pressure. Impairment of cerebral autoregulation, during and after cardiopulmonary bypass (CPB), may increase risk of neurologic injury in neonates undergoing surgery. In this study, alterations of cerebral autoregulation were assessed in a neonatal swine model probing four perfusion strategies.MethodsNeonatal swine (n = 25) were randomized to continuous deep hypothermic cardiopulmonary bypass (DH-CPB, n = 7), deep hypothermic circulatory arrest (DHCA, n = 7), selective cerebral perfusion (SCP, n = 7) at deep hypothermia, or normothermic cardiopulmonary bypass (control, n = 4). The correlation coefficient (LDx) between laser Doppler measurements of CBF and mean arterial blood pressure was computed at initiation and conclusion of CPB. Alterations in cerebral autoregulation were assessed by the change between initial and final LDx measurements.ResultsCerebral autoregulation became more impaired (LDx increased) in piglets that underwent DH-CPB (initial LDx: median 0.15, IQR [0.03, 0.26]; final: 0.45, [0.27, 0.74]; p = 0.02). LDx was not altered in those undergoing DHCA (p > 0.99) or SCP (p = 0.13). These differences were not explained by other risk factors.ConclusionsIn a validated swine model of cardiac surgery, DH-CPB had a significant effect on cerebral autoregulation, whereas DHCA and SCP did not.ImpactApproximately half of the patients who survive neonatal heart surgery with cardiopulmonary bypass (CPB) experience neurodevelopmental delays. This preclinical investigation takes steps to elucidate and isolate potential perioperative risk factors of neurologic injury, such as impairment of cerebral autoregulation, associated with cardiac surgical procedures involving CPB.We demonstrate a method to characterize cerebral autoregulation during CPB pump flow changes in a neonatal swine model of cardiac surgery.Cerebral autoregulation was not altered in piglets that underwent deep hypothermic circulatory arrest (DHCA) or selective cerebral perfusion (SCP), but it was altered in piglets that underwent deep hypothermic CBP.

J-shaped sternotomy in aortic valve repair and ascending aorta replacement. Short-term results

Objective: to evaluate the short-term outcomes of surgical treatment of aortic valve and ascending aorta defects performed through mini-sternotomy using normothermic cardiopulmonary bypass and hyperkalemic cardioplegia via Calafiori technique from May 8, 2019 to May 14, 2020. Materials and methods . The study enrolled 80 patients with isolated aortic valve disease and combined pathology of the aortic root and ascending aorta. It lasted from May 8, 2019 to May 14, 2020. The patients were divided into two groups: Group 1 included 30 patients in whom the upper median J-shaped sternotomy was applied as an access, while Group 2 consisted of 50 patients in whom standard median sternotomy was used as an access. The patients consisted of 43 (53.7%) males and 37 (46.3%) females; the average age was 55.1 ± 11.6 years. All patients were examined before surgery. It revealed no statistically significant differences between the two groups. Results. Group 2 had a 30-day mortality of 2% (n = 1) due to the development of acute heart failure against the background of heart rhythm disturbances. One patient in this group had a late mortality due to acute cerebrovascular accident occurring a month after discharge, which corresponded to 2% (n = 1). There were no deaths in Group 1. In Group 1, there were two conversions (6.7%) to longitudinal median sternotomy. In the first case, it was not possible to restore heart rhythm through repeated defibrillator discharges from mini-sternotomy access due to the presence of an adhesive process in the pericardial cavity. In the second case, ligation of the right internal thoracic artery was required after sternal wire sutures. Artificial ventilation (AV) lasted for 170.9 ± 70.2 minutes in Group 1 and 358.2 ± 169.5 minutes in Group 2. Cardiac activity was independently restored in 23 patients (77%) in Group 1, and in 12 (24%) in Group 2 (p &lt; 0.001). Intraoperative blood loss was 400 ± 150 mL and 850 ± 150 mL (p &lt; 0.05) in Group 1 and Group 2, respectively. In the early postoperative period, it was 200 ± 150 mL in Group 1 and 350 ± 150 mL in Group 2. The length of stay at the intensive care unit and the duration of intensive therapy did not exceed 1 day in both groups. In the early postoperative period, 4 patients in Group 1 (13%) and 27 patients in Group 2 (54%) needed inotropic support (p &lt; 0.001). The need for painkillers and non-steroidal anti-inflammatory drugs was within 3–4 days in Group 1 and 8–10 days in Group 2. In-hospital postoperative period varied from 10 to 16 days in both groups, depending on the severity of the initial condition, presence of concomitant diseases and the need to select an adequate anticoagulant dose. The patients were discharged in satisfactory condition under the supervision of a cardiologist at their homes. There were no inflammatory complications in the access area in both groups during their in-hospital stay. Among the complications in the mid-term postoperative period, two months after discharge, mediastinitis was observed in Group 2. The patient was re-hospitalized, after a course of antibiotic therapy which resolved the mediastinitis; sternal osteosynthesis was performed. Conclusion . Based on the study, it has been shown that this technique reduces the duration of mechanical ventilation, ensures early extubation, decreases blood loss, and, accordingly, ensures the use of replacement therapy, chest stability and a better cosmetic effect. It should be noted that there was no mortality and sternal complications in the patient group with a minimally invasive approach.

Minimum Alveolar Concentration of Sevoflurane as a Single Hypnotic Agent to Maintain BIS Below 50 in Patients During Normothermic Cardiopulmonary Bypass

Minimum alveolar concentration (MAC) of volatile anesthetic agents to maintain bispectral index (BIS) below 50 in 50% of patients was defined as MACBIS50. The primary objective of this study was to determine the minimum alveolar concentration of sevoflurane as a single hypnotic agent to maintain BIS below 50 in patients during normothermic cardiopulmonary bypass. Prospective and observational study. Dante Pazzanese Institute of Cardiology, Brazil. Eighteen consecutive patients scheduled for elective coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB) under general anesthesia, American Society of Anesthesiologists physical status classes III and IV, between the ages of 40 and 70, were included in the study. All patients underwent inhalation induction with facial mask using sevoflurane (Cristália) in 100% oxygen, pancuronium (Cristália) 0.1 mg/kg, and sufentanil (Cristália) 0.5 µg/kg intravenously (IV) administered. A single bolus dose of sufentanil, 1.0 µg/kg IV, was administered before surgical incision. MACBIS50 was calculated using the midpoint concentration of patients involving a crossover (BIS < or ≥50) according to Dixon's Up-and-Down method. The Up-and-Down sequence also was analyzed by probit test that enabled the authors to obtain the effective dose 50 (ED50) and effective dose 95 (ED95) of sevoflurane to maintain a BIS value <50, with a 95% confidence interval (95% CI) of the mean. A total of 15 patients were analyzed in this study. MACBIS50 of sevoflurane as a single hypnotic agent was 0.82% (95% CI 0.47-1.16) in patients aged 40 to 70 undergoing CABG during normothermic CPB. The ED50 and ED95 of sevoflurane to maintain a BIS value <50 for the same context were 0.73% (95% CI 0.45-1.00) and 1.39 (95% CI 0.42-2.37) by means of probit analysis, respectively. MACBIS50 of sevoflurane as a single hypnotic agent was 0.82% in patients undergoing CABG during normothermic CPB.

Does supply meet demand? A comparison of perfusion strategies on cerebral metabolism in a neonatal swine model

ObjectiveWe aimed to determine the effects of selective antegrade cerebral perfusion compared with other perfusion strategies on indices of cerebral blood flow, oxygenation, cellular stress, and mitochondrial function. MethodsOne-week-old piglets (n = 41) were assigned to 5 treatment groups. Thirty-eight were placed on cardiopulmonary bypass. Of these, 30 were cooled to 18°C and underwent deep hypothermic circulatory arrest (n = 10), underwent selective antegrade cerebral perfusion at 10 mL/kg/min (n = 10), or remained on continuous cardiopulmonary bypass (deep hypothermic cardiopulmonary bypass, n = 10) for 40 minutes. Other subjects remained on normothermic cardiopulmonary bypass (n = 8) or underwent sham surgery (n = 3). Novel, noninvasive optical measurements recorded cerebral blood flow, cerebral tissue oxyhemoglobin concentration, oxygen extraction fraction, total hemoglobin concentration, and cerebral metabolic rate of oxygen. Invasive measurements of cerebral microdialysis and cerebral blood flow were recorded. Cerebral mitochondrial respiration and reactive oxygen species generation were assessed after the piglets were killed. ResultsDuring hypothermia, deep hypothermic circulatory arrest piglets experienced increases in oxygen extraction fraction (P < .001), indicating inadequate matching of oxygen supply and demand. Deep hypothermic cardiopulmonary bypass had higher cerebral blood flow (P = .046), oxyhemoglobin concentration (P = .019), and total hemoglobin concentration (P = .070) than selective antegrade cerebral perfusion, indicating greater oxygen delivery. Deep hypothermic circulatory arrest demonstrated worse mitochondrial function (P < .05), increased reactive oxygen species generation (P < .01), and increased markers of cellular stress (P < .01). Reactive oxygen species generation was increased in deep hypothermic cardiopulmonary bypass compared with selective antegrade cerebral perfusion (P < .05), but without significant microdialysis evidence of cerebral cellular stress. ConclusionsSelective antegrade cerebral perfusion meets cerebral metabolic demand and mitigates cerebral mitochondrial reactive oxygen species generation. Excess oxygen delivery during deep hypothermia may have deleterious effects on cerebral mitochondria that may contribute to adverse neurologic outcomes. We describe noninvasive measurements that may help guide perfusion strategies.

Challenges in Perioperative Animal Care for Orthotopic Implantation of Tissue-Engineered Pulmonary Valves in the Ovine Model.

Development of valvular substitutes meeting the performance criteria for surgical correction of congenital heart malformations is a major research challenge. The sheep is probably the most widely used animal model in heart valves regenerative medicine. Although the standard cardiopulmonary bypass (CPB) technique and various anesthetic and surgical protocols are reported to be feasible and safe, they are associated with significant morbidity and mortality rates. The premise of this paper is that the surgical technique itself, especially the perioperative animal care and management protocol, is essential for successful outcomes and survival. Ten juvenile and adult female sheep aged 7.8-37.5months and weighing 32.0-58.0kg underwent orthotopic implantation of tissue-engineered pulmonary valve conduits on beating heart under normothermic CPB. The animals were followed-up for 6months before scheduled euthanasia. Based on our observations, we established a guide for perioperative care, follow-up, and treatment containing information regarding the appropriate clinical, biological, and ultrasound examinations and recommendations for feasible and safe anesthetic, surgical, and euthanasia protocols. Specific recommendations were also included for perioperative care of juvenile versus adult sheep. The described surgical technique was feasible, with a low mortality rate and minimal surgical complications. The proposed anesthetic protocol was safe and effective, ensuring both adequate sedation and analgesia as well as rapid recovery from anesthesia without significant complications. The established guide for postoperative care, follow-up and treatment in sheep after open-heart surgery may help other research teams working in the field of heart valves tissue regeneration.

Outcomes of Totally Endoscopic Beating-Heart Tricuspid Repair in Redo Cardiac Surgery

The role of endoscopic surgery in treating late severe tricuspid regurgitation after cardiac surgery has not been well investigated. The aim of this study was to evaluate the outcomes of a combination of a beating-heart, minimally invasive approach and a leaflet-augmentation technique in treating tricuspid regurgitation after cardiac surgery. This was a retrospective cohort study. From January 2015 to July 2018, patients undergoing reoperative tricuspid valve repair with a totally endoscopic approach were enrolled. Procedures were performed on beating hearts with normothermic cardiopulmonary bypass (CPB). A total of 43 adults (mean age 53.4±11.4 yr; 9 men) met the inclusion criteria. The interval between prior cardiac surgery and current tricuspid repair was 17.6±6.5 years. Ten (10) patients had previous tricuspid repair and concomitant previous cardiac surgery. In the current endoscopic approach, tricuspid repair techniques included 38 leaflet augmentations, 38 annular ring placements, five artificial chordae, one cleft closure, five commissure recreations, and eight papillary muscle relaxations. Mean CPB time, median ventilation time, and median hospital stay were 128.5±54.2 minutes, 20.5 hours (range, 6-436 hrs), and 7 days (range, 4-56 d), respectively. There were only three in-hospital deaths and no follow-up mortality. The regurgitant jet area was decreased from 21.5±12.1 cm2 preoperatively to 2.4±2.2 cm2 postoperatively (p<0.001). In patients with previous tricuspid repair, although the technique of valvuloplasty seems more complex, CPB time, procedure time and hospital stay were not longer than in patients who did not have previous tricuspid repair. Beating-heart, video-assisted, minimal access tricuspid repair after previous cardiac surgery is feasible, reproducible, and associated with low mortality, even in patients who have had previous tricuspid repair.

Lower limit of adequate oxygen delivery for the maintenance of aerobic metabolism during cardiopulmonary bypass in neonates

BackgroundThe objective of cardiopulmonary bypass (CPB) is to maintain an adequate balance between oxygen delivery (Ḋo2) and consumption. The critical Ḋo2 is that at which consumption becomes supply dependent. This study aimed to identify the critical Ḋo2 in neonates, who have higher metabolic rates than adults. MethodsIn a retrospective cohort of neonates, Ḋo2 was calculated from CPB parameters recorded during aortic cross-clamping. High lactate concentration measured after aortic unclamping (lactOFF) was used to identify anaerobic metabolism. Data were analysed using mixed linear and proportional odds regression models. The relationship between Ḋo2 and temperature was analysed in a subgroup of patients with lactOFF <2.5 mM, thought to have had balanced oxygen delivery and consumption. The estimated regression coefficient was further used to adjust hypothetical Ḋo2 thresholds, and Ḋo2 excursions below the threshold were quantified as magnitude–durations. The lowest threshold that provided magnitude–durations and linked with an increase in lactOFF was used as the lowest suitable (critical) Ḋo2 at 37°C. ResultsOverall, 22 896 time points were analysed in 180 neonates. In 40 patients with lactOFF <2.5 mM, Ḋo2 varied by 22.87 (0.70) ml min−1 m−2 °C−1. When varying the Ḋo2 threshold between 340 and 380 ml min−1 m−2, excursions below the threshold were linked with incremental lactOFF. A 100 ml m−2 excursion below the 340 ml min−1 m−2Ḋo2 threshold increased the risk of a 1 mM increment in lactOFF by 22% (odds ratio: 1.22; 95% confidence interval: 1.02–1.45). ConclusionsIt was found that 340 ml min−1 m−2 is likely to represent the lowest suitable Ḋo2 required in neonates to maintain aerobic metabolism during normothermic CPB.