Neuroprotection during cardiac surgery

Cardiac surgery continues to be associated with significant adverse cerebral outcomes, ranging from stroke to cognitive decline. The underlying mechanism of the associated cerebral injury is incompletely understood but is believed to be primarily caused by cerebral embolism and hypoperfusion, exacerbated by ischemia/reperfusion injury. Extensive research has been undertaken in an attempt to minimize the incidence of perioperative cerebral injury, and both pharmacological and nonpharmacological strategies have been investigated. Although many agents demonstrated promise in preclinical studies, there is currently insufficient evidence from clinical trials to recommend the routine administration of any pharmacological agents for neuroprotection during cardiac surgery. The nonpharmacological strategies that can be recommended on the basis of evidence include transesophageal echocardiography and epiaortic ultrasound-guided assessment of the atheromatous ascending aorta with appropriate modification of cannulation, clamping or anastomotic technique and optimal temperature management. Large-scale randomized controlled trials are still required to address further the issues of optimal pH management, glycemic control, blood pressure management and hematocrit during cardiopulmonary bypass. Past, present and future directions in the field of neuroprotection in cardiac surgery will be discussed.     

Brain function after resuscitation from cardiac arrest

PURPOSE OF REVIEW: In industrial countries the incidence of cardiac arrest is still increasing. Almost 80% of cardiac arrest survivors remains in coma for varying lengths of time and full cerebral recovery is still a rare event. After successful cardiopulmonary resuscitation, cerebral recirculation disturbances and complex metabolic postreflow derangements lead to death of vulnerable neurons with further deterioration of cerebral outcome. This article discusses recent research efforts on the pathophysiology of brain injury caused by cardiac arrest and reviews the beneficial effect of therapeutic hypothermia on neurologic outcome along with the recent approach to prognosticate long-term outcome by electrophysiologic techniques and molecular markers of brain injury. RECENT FINDINGS: Recent experimental studies have brought new insights to the pathophysiology of secondary postischemic anoxic encephalopathy demonstrating a time-dependent cerebral oxidative injury, increased neuronal expression, and activation of apoptosis-inducing death receptors and altered gene expression with long-term changes in the molecular phenotype of neurons. Recently, nuclear MR imaging and MR spectroscopic studies assessing cerebral circulatory recovery demonstrated the precise time course of cerebral reperfusion after cardiac arrest. Therapeutic hypothermia has been shown to improve brain function after resuscitation from cardiac arrest and has been introduced recently as beneficial therapy in ventricular fibrillation cardiac arrest. SUMMARY: Electrophysiologic techniques and molecular markers of brain injury allow the accurate assessment and prognostication of long-term outcome in cardiac arrest survivors. In particular, somatosensory evoked potentials have been identified as the method with the highest prognostic reliability. A recent systematic review of 18 studies analyzed the predictive ability of somatosensory evoked potentials performed early after onset of coma and found that absence of cortical somatosensory evoked potentials identify patients not returning from anoxic coma with a specificity of 100%.     

丙泊酚持续静脉输注治疗外伤性颅脑损伤患者手术后脑水肿疗效观察

目的探讨丙泊酚持续静脉输注治疗外伤性颅脑损伤患者手术后脑水肿的临床疗效。方法将2012年1月至2013年12月急诊入院的外伤性颅脑损伤患者68例随机分为对照组与观察组,每组各34例。两组患者均行急诊开颅手术治疗后,对照组给予术后常规脱水降低颅内压、止血、抗感染、营养神经及其他对症支持治疗;观察组在对照组治疗用药的基础上,于手术后第1天即开始接受丙泊酚持续静脉输注治疗。先给予丙泊酚1.5 mg·kg-1静推作为镇静诱导,再对患者进行持续静脉输注0.3~0.4 mg·kg-1·h-1,用药时间至少持续到手术后第3天。使用CT检查术后患者脑水肿的动态变化情况,并监测患者颅内压(ICP)变化,术后6个月随访,使用MMSE评分量表对两组患者进行评分。结果观察组患者手术后第3~4天及第7~8天脑水肿量较对照组有明显减少(P0.01);术后第1天、第4天、第7天、第10天观察组ICP均显著低于对照组(P0.01);术后6个月观察组患者MMSE评分较对照组有所增高,但差异无统计学意义(P0.05)。结论丙泊酚静脉持续输注可有效减轻外伤性颅脑损伤患者手术后脑水肿的程度,降低颅内压,从而提高外伤性颅脑损伤手术的疗效。     

Neurologic dysfunctions following cardiac surgery.

This article has discussed three major categories of neurologic injury following cardiac surgery. The primary pathophysiologic mechanisms for cerebral injury are thought to be related to reperfusion phenomena and neuronal cellular changes, hypoperfusion, and microemboli while on CPB. The type of symptoms the patient manifests range from fatal cerebral injury to more commonly seen episodes of mild, transient confusion. Preoperative, intraoperative, and postoperative risk factors are discussed. The critical care nurse's role in assessing early detection of changes, offering reassurance to both the family and patient, and providing continuity of care are summarized.     

Evaluation of the effect of one large dose of erythropoietin against cardiac and cerebral ischemic injury occurring during cardiac surgery with cardiopulmonary bypass: a randomized double-blind placebo-controlled pilot study

Cardiac surgery and cardiopulmonary bypass (CPB) induce ischemia–reperfusion and subsequent cellular injury with inflammatory reaction. Clinical and experimental studies suggest that recombinant human erythropoietin (EPO) independently of its erythropoietic effect may be used as a cytoprotective agent against ischemic injury. We tested the hypothesis that one large dose of EPO administered shortly before CPB prevents the elevation of cardiac and cerebral ischemic blood markers as well as the systemic inflammatory response induced by cardiac surgery with CBP through this randomized double‐blind placebo‐controlled pilot trial. Fifty patients scheduled for coronary artery bypass graft (CABG) surgery with CPB were randomly allocated to EPO or control groups. EPO (800 IU/kg intravenously) or placebo (saline) was administered before CPB. The primary end point was to study the effect of EPO administration on several blood markers of myocardial and cerebral ischemia in relation to CABG with CPB. In both groups, surgery increased plasma concentrations of cardiac (troponin T, NT‐proBNP, and creatine kinase MB) and cerebral (S100β protein) markers ischemic as well as the pro‐inflammatory marker interleukin‐6. Compared with the placebo, EPO administration before CPB did not prevent an increase of all these markers following CPB. In conclusion, one large dose of EPO, given shortly before CPB, did not protect against cardiac and cerebral ischemia and inflammatory response occurring during CABG surgery with CPB. Although the long‐term clinical implications remain unknown, the findings do not support use of EPO at this dose as a cytoprotective agent in patients undergoing cardiac surgery.     

实体器官移植患者接受心脏外科手术的围术期分析

目的评估实体器官移植患者接受心脏外科手术的安全性和预后。 方法回顾性收集2010年1月至2019年8月期间复旦大学附属中山医院收治的实体器官移植术后接受心脏外科手术患者的临床资料,包括年龄、性别、基础疾病、器官移植种类、器官移植至本次心脏外科手术时间、辅助检查、手术情况、围术期并发症、重症监护病房住院时间、总住院时间,并对存活患者进行随访。 结果共纳入14例实体器官移植患者,其中12例（85.7%）为肾移植,1例（7.1%）为肝移植,1例（7.1%）为心脏移植。患者平均年龄（57.5±6.0）岁,移植至本次心脏外科手术平均时间（11.4±5.5）年。平均重症监护病房住院时间（3.6±4.3）天,平均住医院时间（18.4±8.4）天。围术期并发症包括急性肾损伤2例（14.3%）,其中1例（7.1%）需要行连续性肾脏替代治;新发心房颤动1例（7.1%）;术后感染3例（21.4%）,均为肺部感染。30 d内死亡患者2例（14.3%）。存活患者随访3~124个月,平均（38.7±40.3）个月,随访期间无患者死亡,均未出现再住院治疗。 结论实体器官移植患者接受心脏外科手术具有良好的短期及长期预后。然而,围术期的感染风险、术后急性肾损伤的发生仍需密切关注。     

Minimally invasive valve surgery: different techniques and approaches

Less invasive approaches to cardiac surgical procedures are being developed in an effort to decrease patient morbidity and enhance postoperative recovery in comparison with conventional methods. Although full median sternotomy has been the standard surgical approach to the heart for more than 30 years, minimally invasive techniques using limited incisions are rapidly gaining acceptance. Potential advantages of a small skin incision include less trauma and tissue injury, leading to a less painful and quicker overall recovery, as well as shorter hospital stays for patients. Decreasing the size of the skin incision for minimally invasive valve surgery to significantly less than the cardiac size requires specific access to the valve to be repaired or replaced. Thus, various minimally invasive techniques and approaches have been described for aortic and mitral valve surgery. This article will review the different minimally invasive techniques and approaches, as well as early results and outcomes for aortic and mitral valve surgery.     

The recognition and prevention of border zone cerebral ischaemia during cardiac surgery.

Four patients who sustained bilateral occipital and parietal lobe ischaemia during cardiac surgery for coronary artery bypass are described. The features include cortical blindness, visual disorientation, disturbances of reading and constructional dyspraxia. The symptoms tended to improve over about six weeks and good visual acuity was regained in all instances. The likeliest cause is generalized cerebral hypotension. Ischaemic injury might be prevented by prior detection of extracranial arterial disease and by monitoring cerebral as well as cardiac activity during surgery.     

Telephone support in the early post-discharge period following elective cardiac surgery: does it reduce anxiety and depression levels?

Over the last decade, much has been published concerning the information needs of patients and their families on and after discharge from hospital. With ever-decreasing lengths of stay in hospital following cardiac surgery as a result of technological improvements and the relentless pressure for beds, the time available for nurses to attend to these needs has been reduced dramatically, thus presenting new challenges to nurses. This study examines the levels of anxiety and depression in 78 elective cardiac surgery patients on discharge and at five weeks after, but before their recall to the outpatient department. The study tests the hypothesis that telephone follow-up from the ward will reduce patients' anxiety and depression levels in the early post-discharge period. The findings indicated that patients found follow-up calls beneficial and helpful, but follow-up calls did not reduce anxiety and depression levels in the early post-discharge period.     

Successful resuscitation of an elderly patient following cardiac arrest: possible role of reduction of reactive oxygen

The presence of hyperoxia during reperfusion following brain ischemia has been shown in experimental animals to result in increased mortality and increased lipid peroxidation. Although no human studies have been reported, prolonged hyperoxia after resuscitation from cardiac arrest probably would result in increased cerebral injury. We report the case of an 88-year-old man who had a 5- to 6-minute cardiac arrest and then had decerebrate posturing during the post-resuscitation period, indicating that he had suffered a significant ischemic/anoxic insult. Early attention was paid to normalizing the arterial Po2 following resuscitation, which, according to experimental evidence, contributed to his eventual complete recovery of neurologic function, including mental state.     

Minimally invasive valve surgery: different techniques and approaches

Less invasive approaches to cardiac surgical procedures are being developed in an effort to decrease patient morbidity and enhance postoperative recovery in comparison with conventional methods. Although full median sternotomy has been the standard surgical approach to the heart for more than 30 years, minimally invasive techniques using limited incisions are rapidly gaining acceptance. Potential advantages of a small skin incision include less trauma and tissue injury, leading to a less painful and quicker overall recovery, as well as shorter hospital stays for patients. Decreasing the size of the skin incision for minimally invasive valve surgery to significantly less than the cardiac size requires specific access to the valve to be repaired or replaced. Thus, various minimally invasive techniques and approaches have been described for aortic and mitral valve surgery [111]. This article will review the different minimally invasive techniques and approaches, as well as early results and outcomes for aortic and mitral valve surgery.     

Blood cardioplegia filtration

The introduction of blood cardioplegia has been proven to limit ischaemia and reperfusion injury in cardiac surgery. But the presence of activated neutrophils in the capillary bed may cause further damage. Leukocyte filters have been shown to be very effective in reducing the leukocytes in blood cardioplegia to less than 10%. Leukocyte depletion of blood cardioplegia provides an excellent approach to minimizing myocardial injury, predominantly in high-risk cardiac surgery.     

The Recognition and Prevention of Border Zone Cerebral Ischaemia During Cardiac Surgery

Four patients who sustained bilateral occipital and parietallobe ischaemia during cardiac surgery for coronary artery bypassare described. The features include cortical blindness, visualdisorientation, disturbances of reading and constructional dyspraxia.The symptoms tended to improve over about six weeks and goodvisual acuity was regained in all instances. The likeliest causeis generalized cerebral hypotension. Ischaemic injury mightbe prevented by prior detection of extracranial arterial diseaseand by monitoring cerebral as well as cardiac activity duringsurgery.     

Echocardiographic evaluation of hemodynamics and myocardial function in children under 1 year of age following surgery under conditions of artificial blood circulation

Left and right ventricular myocardial contractility was assessed, using two-dimensional echocardiography in the earliest postoperative period after cardiopulmonary bypass surgery in 60 children under 1 year of age. It has been shown that a hemodynamically smooth postoperative period is characterized by a 36 to 40% decrease in left ventricular ejection fraction depending on the type of heart valve defect and the variant of its correction. Such a decrease in contractility required a slight inotropic support in the first 24 hours after the operation; in this case cardiac index exceeded 2.5 l.min-1.m-2 already in the first postoperative hours. By day 15 after the operation cardiac index and ventricular contractility are fully normalized, but for cases when correction is of hemodynamic and not of anatomic nature or is accompanied by myocardial injury.     

The postcardiac injury syndrome: case report and review of the literature

The postcardiac injury syndrome (PCIS) includes the postmyocardial infarction syndrome, the postcommissurotomy syndrome, and the postpericardiotomy syndrome. Dressler reported a series of patients who developed a pericarditis-like illness days to weeks after a myocardial infarction. Postcardiac injury syndrome also has been observed after cardiac surgery, percutaneous intervention, pacemaker implantation, and radiofrequency ablation. Postcardiac injury syndrome is characterized by pleuritic chest pain, low-grade fever, an abnormal chest x-ray, and the presence of exudative pericardial and/or pleural effusions. The pathophysiology of PCIS involves auto-antibodies that target antigens exposed after damage to cardiac tissue. The treatment of PCIS includes the use of nonsteroidal anti-inflammatory drugs and corticosteroids. Prophylactic use of corticosteroids before cardiac surgery has not been effective in preventing PCIS. The widespread use of reperfusion therapy and cardiac medications with anti-inflammatory properties may have reduced the incidence of PCIS. Although PCIS can follow a relapsing course, it does carry a favorable prognosis.     

Mild hypothermia alone or in combination with anesthetic post-conditioning reduces expression of inflammatory cytokines in the cerebral cortex of pigs after cardiopulmonary resuscitation

Introduction  

Hypothermia improves survival and neurological recovery after cardiac arrest. Pro-inflammatory cytokines have been implicated in focal cerebral ischemia/reperfusion injury. It is unknown whether cardiac arrest also triggers the release of cerebral inflammatory molecules, and whether therapeutic hypothermia alters this inflammatory response. This study sought to examine whether hypothermia or the combination of hypothermia with anesthetic post-conditioning with sevoflurane affect cerebral inflammatory response after cardiopulmonary resuscitation.     

Predictors of oral feeding difficulty in cardiac surgical infants

PURPOSE: The purpose of this study was to identify factors contributing to postoperative feeding difficulties in neonates following cardiac surgery. METHODS: A retrospective cohort study used chart audit of 101 consecutive infants who underwent cardiac surgery. Ten variables were analyzed as possible predictors of postoperative feeding difficulties including: diagnosis, demographics, details of surgery, and postoperative course. RESULTS: At hospital discharge, 72 (71.3%) infants were orally feeding and 29 (28.7%) were not. Overall mean hospital length of stay was 17.73 (+ 16.40 days). Multivariate logistic regression analysis revealed vocal chord injury (odds ratio 11.80), length of postoperative intubation (odds ratio 1.10 per day), and weight at surgery (odds ratio 0.34) as independent predictors of failure to feed orally at discharge from hospital. CONCLUSION: Risk factors for feeding difficulties in the postcardiac surgery infant are vocal chord injury, prolonged intubation, and low weight at surgery. Early identification of neonates at risk for feeding difficulties may lead to development of strategies to reduce morbidity, improve patient care, and provide better resource utilization.     

Preliminary study of the relationship between the cardiopulmonary arrest time and its consequences in trauma patients

The proposal of this research was to obtain parameters to start or maintain cardiopulmonary resuscitation (CPR) in victims of trauma. The duration of the cardiac arrest and the CPR of the survivors was described, as well as the cerebral performance and the mortality of these victims 24, 48 and 72 hours after these events had happened. With the results of this characterization the relation between duration of cardiac arrest time, CPR and mortality were described. Data for this report were collected in Hospital das Clínicas da Faculdade de Medicina da Universidade de S?o Paulo emergency department. A big amount of the victims (93.4%) presents severe trauma and main cause of death was brain injury. Survival at 72 hours after CPR was 10%. The assessment, during the 72 hour period, of the survivors from cardiac arrest of traumatic cause has shown bad cerebral performance of those victims in that period of time. The survivor after the first episode of CPR was strongly related to cardiac arrest time when compared with CPR time. The time of cardiac arrest < or = 4 minutes and CPR < or = 20 minutes was related to survival more than 72 hours.     

Pyruvate enhances neurological recovery following cardiopulmonary arrest and resuscitation

PURPOSE: Cerebral oxidative stress and metabolic dysfunction impede neurological recovery from cardiac arrest-resuscitation. Pyruvate, a potent antioxidant and energy-yielding fuel, has been shown to protect against oxidant- and ischemia-induced neuronal damage. This study tested whether acute pyruvate treatment during cardiopulmonary resuscitation can prevent neurological dysfunction and cerebral injury following cardiac arrest. METHODS: Anesthetized, open-chest mongrel dogs underwent 5 min cardiac arrest, 5 min open-chest cardiac compression (OCCC), defibrillation and 3-day recovery. Pyruvate (n=9) or NaCl volume control (n=8) were given (0.125 mmol kg(-1) min(-1) i.v.) throughout OCCC and the first 55 min recovery. Sham dogs (n=6) underwent surgery and recovery without cardiac arrest-resuscitation. RESULTS: Neurological deficit score (NDS), evaluated at 2-day recovery, was sharply increased in NaCl-treated dogs (10.3+/-3.5) versus shams (1.2+/-0.4), but pyruvate treatment mitigated neurological deficit (NDS=3.3+/-1.2; P<0.05 versus NaCl). Brain samples were taken for histological examination and evaluation of inflammation and cell death at 3-day recovery. Loss of pyramidal neurons in the hippocampal CA1 subregion was greater in the NaCl controls than in pyruvate-treated dogs (11.7+/-2.3% versus 4.3+/-1.2%; P<0.05). Cardiac arrest increased caspase-3 activity, matrix metalloproteinase activity, and DNA fragmentation in the CA1 subregion; pyruvate prevented caspase-3 activation and DNA fragmentation, and suppressed matrix metalloproteinase activity. CONCLUSION: Intravenous pyruvate therapy during cardiopulmonary resuscitation prevents initial oxidative stress and neuronal injury and enhances neurological recovery from cardiac arrest.