Effect of the Pulsatile Extracorporeal Membrane Oxygenation on Hemodynamic Energy and Systemic Microcirculation in a Piglet Model of Acute Cardiac Failure

The objective of this study was to compare the effects of pulsatile and nonpulsatile extracorporeal membrane oxygenation (ECMO) on hemodynamic energy and systemic microcirculation in an acute cardiac failure model in piglets. Fourteen piglets with a mean body weight of 6.08 ± 0.86 kg were divided into pulsatile (N = 7) and nonpulsatile (N = 7) ECMO groups. The experimental ECMO circuit consisted of a centrifugal pump, a membrane oxygenator, and a pneumatic pulsatile flow generator system developed in-house. Nonpulsatile ECMO was initiated at a flow rate of 140 mL/kg/min for the first 30 min with normal heart beating, with rectal temperature maintained at 36°C. Ventricular fibrillation was then induced with a 3.5-V alternating current to generate a cardiac dysfunction model. Using this model, we collected the data on pulsatile and nonpulsatile groups. The piglets were weaned off ECMO at the end of the experiment (180 min after ECMO was initiated). The animals did not receive blood transfusions, inotropic drugs, or vasoactive drugs. Blood samples were collected to measure hemoglobin, methemoglobin, blood gases, electrolytes, and lactic acid levels. Hemodynamic energy was calculated using the Shepard's energy equivalent pressure. Near-infrared spectroscopy was used to monitor brain and kidney perfusion. The pulsatile ECMO group had a higher atrial pressure (systolic and mean), and significantly higher regional saturation at the brain level, than the nonpulsatile group (for both, P < 0.05). Additionally, the pulsatile ECMO group had higher methemoglobin levels within the normal range than the nonpulsatile group. Our study demonstrated that pulsatile ECMO produces significantly higher hemodynamic energy and improves systemic microcirculation, compared with nonpulsatile ECMO in acute cardiac failure.

Evaluation of a novel oxidation ditch system for biological nitrogen and phosphorus removal from domestic sewage

A novel oxidation ditch system using anaerobic tanks and innovative dual dissolved oxygen (DO) control technology is proposed for biological nitrogen and phosphorus removal from domestic sewage. A continuous bench-scale experiment running for more than 300 days was performed to evaluate the system. Monitoring and controlling the airflow and recirculation flow rate independently using DO values at two points along the ditch permitted maintenance of aerobic and anoxic zone ratios of around 0.30 and 0.50, respectively. The ability to optimize aerobic and anoxic zone ratios using the dual DO control technology meant that a total nitrogen removal efficiency of 83.2-92.9% could be maintained. This remarkable nitrogen removal performance minimized the nitrate recycle to anaerobic tanks inhibiting the phosphorus release. Hence, the total phosphorus removal efficiency was also improved and ranged within 72.6-88.0%. These results demonstrated that stabilization of the aerobic and anoxic zone ratio by dual DO control technology not only resulted in a marked improvement of nitrogen removal, but it also enhanced phosphorus removal.

[Tricuspid valve replacement using right heart bypass in patient with liver cirrhosis]

A successful case with liver cirrhosis underwent re-tricuspid valve replacement (TVR) using right heart bypass is reported herein. A 59-year-old lady previously undergone tricuspid valve replacement with bioprosthetic valve had suffered from exertional fatigue as the feature of congestive heart failure. She also presented severe liver dysfunction owing to chronic hepatitis and cardiac liver cirrhosis. She was diagnosed with structural deterioration of bioprosthesis in tricuspid position. She underwent re-TVR with right heart bypass consisted of centrifugal pump, heparin coating circuit and blood reservoir. This system lacked of membranous oxygenator in order not to activate various kinds of chemical mediator which leads to postoperative liver dysfunction. Postoperative course was uneventful and she is doing well 1 year after the operation. Although the mortality of the TVR in the patient with cirrhosis remains still high, this new technique seems to provide better outcome in this kind of patients.

Resection of a large, high-flow arteriovenous malformation during hypotension and hypothermia induced by a percutaneous cardiopulmonary support system. Case report

The key to successful surgical resection of cerebral arteriovenous malformations (AVMs) is control of bleeding and cerebral swelling. Induced hypotension is one of the most valuable means of achieving this control. The authors introduced induced hypotension with mild hypothermia by using a percutaneous cardiopulmonary support system (PCPS) to resect a large, high-flow AVM. The efficacy and technical points of this method are discussed. The PCPS, whose entire intraluminal surface was coated with heparin, was established through a transfemoral route. During resection of the AVM, a mean arterial blood pressure of 60 mm Hg and a mean body temperature of 30 degrees C were easily maintained by regulating the flow rate of the PCPS and by blood cooling. The activated coagulation time was maintained at approximately 250 seconds with a minimum systemic administration of heparin. The authors report the case of a 30-year-old woman who presented with intraventricular hemorrhage and was diagnosed as having a large, high-flow AVM located in the left sylvian fissure. The AVM was fed by the left middle, posterior, and anterior cerebral arteries and drained by the many cortical ascending veins and the basal vein. The patient underwent surgery after hypotension and hypothermia had been induced via the PCPS method. Induced hypotension decreased the tension of the nidus and made its dissection easier. The AVM was totally resected and no hemostatic difficulties were encountered. On the basis of the authors' experience, they suggest that hypotension and hypothermia induced by using the PCPS is a powerful tool for the successful resection of large, high-flow AVMs.

[Anesthesia for pediatric open heart surgery without transfusion]

We reviewed 50 recent anesthetic managements of pediatric patients for open heart surgery weighing between 6.5 to 12 kg to evaluate factors contributing to successful management without transfusion. Twenty six cases were managed without transfusion, whereas nine cases required less than 30 ml.kg-1 of transfusion and the other 15 cases needed massive transfusion amounting to more than 50 ml.kg-1. The followings are important factors to complete the open surgery without transfusion; 1) the patient's weight is 9 kg or more, 2) the duration of cardiopulmonary bypass is less than 120 minutes, and 3) intraoperative bleeding is less than 10 ml.kg-1. We could find several advantages in patients without transfusion, compared with those receiving transfusion, such as greater urine output, less bleeding during the surgery, more concentrated platelet and better respiratory condition after the surgery. In addition, the lager the amount of transfusion we observed the more disadvantageous to the patients. Even if transfusion can not be avoided, minimal transfusion of the washed red cell is favorable.

[Comparison of cerebral oxygen metabolism during normothermic versus moderate hypothermic cardiopulmonary bypass]

We compared the effects of normothermic (NCPB, N = 5) and moderate hypothermic (HCPB, (N = 5) cardiopulmonary bypass on cerebral oxygen metabolism in patients undergoing coronary artery bypass grafting. For monitoring of cerebral oxygenation, we used jugular venous oxyhemoglobin saturation (SjVO2) and near infrared spectroscopy (NIR). In NCPB group, although SjVO2 decreased temporally at the start of cardiopulmonary bypass, it became stabilized above 50% during the rest of cardiopulmonary bypass. In HCPB group, on the contrary, oxyhemoglobin measured by NIR showed maximum decrease during rewarming under cardiopulmonary bypass. Furthermore, SjVO2 decreased under 50% at the end of cardiopulmonary bypass (3/5 cases). We consider that NCPB is a useful technique for preventing cerebral hypoxia, if the decrease of SjVO2 during the early period of cardiopulmonary bypass is avoidable. Lastly, we also advocate that both SjVO2 and NIR are useful monitoring systems for continuous evaluation of cerebral oxygen metabolism during cardiopulmonary bypass.

[Anterior choroidal artery territory infarction with transcortical sensory aphasia after a neck clipping of left internal carotid artery aneurysms: a case report]

Anterior choroidal artery (Ach A) syndrome is widely known to be composed of a triad of hemiparesis, hemisensory loss and homonymous hemianopia. The authors report a case of Ach A-territory infarction after a direct operation for internal carotid artery aneurysms, which presented transcortical sensory aphasia in association with the characteristic triad. The literature and several previously reported cases with dominant and nondominant cerebral hemisphere signs in AcH A infarction are reviewed. The danger of Ach A occlusion and the importance of preserving it during aneurysm surgery are emphasized.

Glucagon-secreting pancreatic islet cell carcinoma, containing insulin and somatostatin, with hypoglycemic attack

A patient with glucagonoma syndrome and hypoglycemic attack is presented. Total pancreatectomy was performed with splenectomy and excision of the metastatic nodule in the liver. Diagnosis of glucagon-secreting A cell carcinoma of the pancreas was confirmed by hormone assays and morphological studies with light and electron microscopy. Glucagon, insulin, and somatostatin were demonstrated immunohistochemically in the tumor tissue. Multihormonal features of the endocrine pancreatic tumors are discussed.