Brain resuscitation by extracorporeal circulation after prolonged cardiac arrest in cats

Objective Brain reanimation after prolonged ischemia is limited by post-ischemic reperfusion deficits (no-reflow phenomenon). The present study was undertaken to establish whether after 30 min cardiac arrest extracorporeal circulation is able to restore brain reperfusion and to promote functional and metabolic recovery.Design Adult normothermic cats were submitted to 30 min cardiac arrest by KCl-induced cardioplegia. Resuscitation was carried out by extracorporeal circulation (ECC) until spontaneous heart function returned. The quality of brain recovery was assessed 3 h later by electrophysiological recording and by imaging of the regional distribution of brain energy metabolites.Results In 6 of 10 cats cardiac sinus rhythm returned after 32±15 min. In the other 4 cats cardiac function did not return or only intermittently returned during the 3 h observation period. Cerebral blood flow measured by laser Doppler flowmetry returned to 102%±40% of control immediately after the beginning of resuscitation but then gradually declined to 43%±32% after 3 h despite normotensive perfusion. In all cats pupils started to constrict within less than 5 min of recirculation but in 2 animals they secondarily dilated 1.5 and 2 h later, respectively. Spontaneous EEG activity reappeared in 4 of the 6 successfully resuscitated cats after 111±40 min but failed to recover in the others. Bioluminescent imaging of ATP after 3 h recirculation revealed near-complete depletion throughout the brain in all 4 cats without cardiac recovery. Of the 6 successfully resuscitated cats 5 exhibited patchy areas of low ATP, glucose and pH in 22%–92% of the cross sectional area of brain; in one cat recovery of energy metabolism and acid-base homoiostasis was homogenous without any focal deficits. The cross sectional area of ATP recovery correlated directly with CBF and hematocrit and inversely with the plasma lactate level.Conclusions This study demonstrates for the first time that ECC is able to restore electrophysiological and metabolic brain function after cardiac arrest of as long as 30 min, but recovery is heavily restricted by delayed postischemic disturbances of recirculation. Progress in cardiac resuscitation by ECC requires substantial improvement in the efficiency of cerebrovascular reperfusion.     

Accidental hypothermia with cardiac arrest: Complete recovery after prolonged resuscitation and rewarming by extracorporeal circulation

A 51-year-old male remained immersed in sea water (6°C) for 40 min. Brought ashore, the ECG showed asystole. Advanced life support was immediately commenced. On arrival in hospital his rectal temperature was 27°C, but continued to fall to 24°C. The ECG remained isoelectric. Cardiopulmonary resuscitation was continued until extracorporeal circulation was established 190 min after rescue. Upon rewarming ventricular fibrillation occurred which was converted to sinus rhythm with a bolus of lignocaine followed by D.C. conversion at 31.5°C. When rewarming was complete after 60 min, signs of severe heart failure became evident. Sternotomy and pericardiotomy were performed to exclude cardiac tamponade. After 60 min of re-perfusion the patient was be weaned from bypass supported by a high-dose vasopressor infusion and nitroglycerine. He was discharged after 13 days with no evidence of any permanent organ damage. Given the advantage of providing circulatory support, extracorporeal circulation may be useful when rewarming hypothermic victims with cardiac arrest.     

Comparison of conventional extracorporeal circulation and minimal extracorporeal circulation with respect to microbubbles and microembolic signals

The intention of minimal extracorporeal circulation (MECC) is to reduce priming volume and minimize contact of blood with polymers and air in a closed system. In contrast to conventional extracorporeal circulation (ECC), a venous reservoir is missing. Thus, air trapping is limited and avoidance of bubble embolism is a major concern. This study investigates microbubbles (MBB) number and size in the venous and arterial lines of ECC and MECC compared to the number of microembolic signals (MES) in the right and left middle cerebral artery (MCA). Twenty patients undergoing coronary surgery were operated either with conventional ECC (cardiotomy reservoir, Rotaflow pump, Quadrox oxygenator, Quart filter) or MECC (Quart filter, Rotaflow pump, Quadrox oxygenator). Number and size of MBB were monitored in the venous and arterial lines with an ultrasound Doppler system. MES in right and left MCAs were measured by transcranial Doppler (TCD) monitoring. Patients undergoing MECC had additional sealing of the venous cannula by a ligature at the site of its insertion into the right atrium. There were no significant differences between groups with respect to age, X-clamping, bypass time and number of distal anastomoses. The number of MES and MBB in the arterial line was comparable between the groups. On the venous side, MECC-perfusion shows a significantly lower number of MBB. This could be explained with the additional sealing of the venous cannula. Furthermore, our data indicate that the MBB-volume reaching the pump will also appear in the arterial outflow and into the patient's MCA. For this reason, the avoidance of air contamination is a major concern for surgeons, anaesthesiologists and perfusionists.     

体外循环心内直视术后急性肾功能不全患者的护理

笔总结体外循环术后发生急性肾功能不全的31例患的护理体会，认为体外循环术后并发急性肾功能不全最主要的原因是术后低心排和低血压，因此防止术后低心排和低血压的发生，能有效预防急性肾功能不全的发生，提高治愈率，一旦发生急性肾衰，宜早期透析治疗。     

Cardiac arrhythmias during coronary bypass surgery without extracorporeal circulation

Ventricular arrhythmias are recorded in most patients at coronary bypass surgery without extracorporeal circulation. The stages, such as the pulling of the sternal edges apart, the opening of the pericardium, the revision and dislocation of the heart, and revascularization of coronary arteries, are most dangerous due to the fact that they may lead to the development of arrhythmias. The major proarrhythmogenic factors at coronary bypass surgery without extracorporeal circulation are mechanical irritation of reflexogenic areas and myocardial ischemia, the mechanical factors playing the leading role in the development of ventricular arrhythmias.     

Use of open chest cardiopulmonary resuscitation after failure of standard closed chest CPR: illustrative cases.

Compared to standard closed chest CPR, open chest cardiac massage improves vital organ perfusion and survival in animal models of medical cardiac arrest. Yet its use is essentially limited to the treatment of traumatic arrest. Three cases of medical cardiac arrest are presented in which open chest compression was used after failure of external chest compression. These cases illustrate the range of potential outcomes and how this therapy can be optimally applied. Approaches we have used to prevent application of futile intensive therapy in patients unlikely to be neurologically intact survivors are described. Replacement of open chest CPR by closed chest CPR as the standard of care for the in-hospital cardiac arrest was not justified by experimental data. The circumstances of refractory cardiac arrest make it unlikely that well controlled human studies will be able to demonstrate the superiority of open chest CPR in selected patients. The decision to use this therapy will likely remain within the art of medicine.     

Oxygen requirement during cardiopulmonary resuscitation (CPR) to effect return of spontaneous circulation

BackgroundRecent scientific evidence has demonstrated the importance of good quality chest compressions without interruption to improve cardiac arrest resuscitation rates, and suggested that a de-emphasis on minute ventilation is needed. However, independent of ventilation, the role of oxygen and the optimal oxygen concentration during CPR is not known. Previous studies have shown that ventilation with high oxygen concentration after CPR is associated with worse neurologic outcome. We tested the hypothesis that initial ventilation during CPR without oxygen improves resuscitation success.MethodsSprague–Dawley rats were anesthetized with ketamine/xylazine (IP), intubated and ventilated with room air. A KCl bolus (0.04 mg/g) was given (IV) to induce asystolic cardiac arrest and ventilation was stopped. At 6 min, CPR was started with an automated chest compressor at a rate of 200–240/min and epinephrine (0.01 mg/kg) was given 1 min later. During CPR, the ventilation rate was 50% of baseline with one of three oxygen concentrations: (1) 0% O₂ (100% N₂), (2) 21% O₂, or (3) 100% O₂. The prescribed oxygen concentration was continued for 2 min after return of spontaneous circulation (ROSC) and then all animals were switched to 100% oxygen for 1 h prior to extubation. Blood gases were measured at baseline, 2 min and 1 h after ROSC. Group comparisons were done using Fisher's exact test and ANOVA.ResultsROSC was achieved in 1/10 (0% O₂), 9/11 (21% O₂) and 10/12 (100% O₂, p < 0.001). ROSC times after starting CPR were 80 s in the 0% O₂, 115 ± 87 s in the 21% O₂ group and 95 ± 33 s in the 100% O₂ group (mean ± SD, p = 0.5). Aortic end-diastolic pressure before ROSC was not different among groups. 100% oxygen ventilation in the first 2 min resulted in higher PaO₂ at ROSC 2 min (109 ± 44 mm Hg vs. 33 ± 8 mm Hg, p < 0.001). Survival to 72 h was 0/1 (0% O₂), 7/9 (21% O₂) and 8/10 (100% O₂) with a low neurologic deficit score in both O₂ groups (NDS range 5–25).ConclusionsIn a mild cardiac arrest model with generally good neurologic recovery, initial CPR ventilation with no O₂ did not allow for ROSC. In contrast, CPR coupled with room air or higher oxygen levels result in a high rate of ROSC with good neurologic recovery. During CPR, the level of oxygenation must be considered, which if too low may preclude initial ROSC.     

连续性血液净化治疗对心肺复苏术后患者脑复苏效果的影响

目的探讨连续性血液净化治疗（CBP）对心肺复苏术（CPR）后患者脑复苏效果的影响及其可能的机制。方法选取CPR术后脑复苏未成功的患者60例随机分为两组，每组30例，采用CBP＋原发病的综合治疗30例作治疗组。采用常规脱水、头部低温＋原发病的综合治疗的30例患者作对照组。观察两组患者脑复苏成功的时间、成功率。结果治疗组患者的脑复苏成功的时间较对照组明显缩短、脑复苏成功率明显高于对照组（P〈0．01），两组患者的死亡率无明显差异（P〉0．05）。结论连续性血液净化治疗对心肺复苏后患者能明显减轻脑水肿，缩短脑水肿的时间，提高脑复苏的成功率。     

Augmentation of Cardiac Output by External Cardiac Pacing: Pacemaker-Induced CPR

Transthoracic cardiac pacing is frequently associated with simultaneous stimulation of skeletal muscle and nerves. We describe a patient in cardiogenic shock and complete heart block in whom the associated vigorous abdominal and chest muscle contractions caused by transthoracic cardiac pacing resulted in a marked augmentation of cardiac output and systemic blood pressure via a "CPR" effect     

Artificial circulation for resuscitation after prolonged clinical death caused by hypoxia.

The dynamics of dying and the subsequent recovery of the main vital functions such as cardiac performance, respiration and unconditioned reflexes were investigated in 24 dogs resuscitated by Bryukhonenko's method of artificial circulation after 13-15 min clinical death caused by asphyxia. Application of artificial circulation during asystole required a gradual increase for 2-3 min in the volume of perfusion to optimum levels, since too rapid an increase of blood flow resulted in secondary ventricular fibrillation. In conditions of resuscitation with high volumes of extracorporeal perfusion (exceeding 100 ml kg-1 min-1), fast return of vital functions, their subsequent normalization, and relatively smooth recovery, can be achieved. Decreasing the rate of blood flow to 60-80 ml kg-1 min-1 delays the recovery of vital functions of the resuscitated organism. Severe post-resuscitation disease develops with a fatal outcome. Resuscitation with flows of 40 ml kg-1 min-1 or less is ineffective. We concluded that successful resuscitation after clinical death caused by asphyxia was possible only when the blood flow was 1.2-1.5 times higher than the normal cardiac output.     

Successful resuscitation with mechanical CPR, therapeutic hypothermia and coronary intervention during manual CPR after out-of-hospital cardiac arrest

A 62-year-old man suffered out-of-hospital cardiac arrest and was treated with mechanical compression-decompression during transport to the hospital. In the emergency department, 28 min after cardiac arrest, spontaneous circulation returned briefly but the patient rapidly became asystolic and mechanical compression-decompression was again applied. After further resuscitation a spontaneous circulation returned and the patient was transferred, deeply comatose, to the coronary intervention laboratory while therapeutic hypothermia was induced. In the laboratory the heart arrested again and coronary angiography was performed during manual CPR revealing a left main stem occlusion. After successful reperfusion of the heart the patient was transferred to the intensive care unit with an intra-aortic balloon pump. The patient was treated with hypothermia for 24 h and awoke without neurological sequelae after a sustained intensive care period of 13 days. The present case is an example of how modern resuscitation principles implementing new clinical and experimental findings may strengthen the chain of survival during resuscitation.     

Acute renal failure after successful cardiopulmonary resuscitation

OBJECTIVE: To assess the frequency and independent predictors of severe acute renal failure in patients resuscitated from out-of-hospital ventricular fibrillation cardiac arrest. DESIGN: A cohort study with a minimum follow-up of 6 months. SETTING: Emergency department of a tertiary care 2200-bed university hospital. PATIENTS AND PARTICIPANTS: Consecutive adult (> 18 years) patients admitted from 1 July 1991 to 31 October 1997 after witnessed ventricular fibrillation out-of-hospital cardiac arrest and successful resuscitation. MEASUREMENTS AND RESULTS: Acute renal failure was defined as a 25% decrease of creatinine clearance within 24 h after admission. Out of 187 eligible patients (median age 57 years, 146 male), acute renal failure occurred in 22 patients (12%); in 4 patients (18%) renal replacement therapy was performed. Congestive heart failure (OR 6.0, 95% CI 1.6-21.7; p = 0.007), history of hypertension (OR 4.4, 95% CI 1.3-14.7; p = 0.02) and total dose of epinephrine administered (OR 1.1, 95% CI 1.0-1.2; p = 0.009) were independent predictors of acute renal failure. Duration of cardiac arrest, pre-existing impaired renal function and blood pressure at admission were not independently associated with renal outcome. CONCLUSIONS: Severe progressive acute renal failure after cardiopulmonary resuscitation (CPR) is rare. Pre-existing haemodynamics seem to be more important for the occurrence of acute renal failure than actual hypoperfusion during resuscitation.