Blood cardioplegia reduces intraoperative ventricular fibrillation and transfusion requirements compared to crystalloid cardioplegia in canine mitral valve repair.

OBJECTIVE: Cardioplegic solutions are indispensable for open-heart surgeries, including mitral valve repair (MVR), a potentially curative treatment for myxomatous mitral valve disease in dogs. However, procedural methodologies are not fully established, and complications are yet to be comprehensively understood. Cardioplegic solutions contain various substances to protect the myocardium under temporal cardiac arrest. Nevertheless, ventricular fibrillation (VF) occurs as a common complication after releasing the crossclamp. Based on these backgrounds, the search for optimal cardioplegic solutions in dogs undergoing MVR is an urgent issue. This study aims to evaluate the occurrence of VF in dogs treated with blood cardioplegia (BCP) versus crystalloid cardioplegia (CCP) during MVR. ANIMALS: A total of 251 client-owned dogs who underwent MVR from November 2015 to November 2017 were included. METHODS: We retrospectively assessed the relationship between VF and type of cardioplegia (CCP or BCP) based on surgical records, including VF incidence, transfusion use, crossclamp time, and echocardiographic measurements. RESULTS: Logistic regression analysis showed that the CCP group was associated with the occurrence of VF (OR, 2.378; CI, 1.133-4.992; P = .022). In addition, the CCP group was associated with transfusion use (OR, 2.586; CI, 1.232-5.428, P = .022). There was no difference between the groups for the pre- and postoperative echocardiographic measurements. CLINICAL RELEVANCE: The BCP group had a lower incidence of VF and less transfusion use than the CCP group. This finding indicates that BCP may be a superior cardioplegic technique for MVR in dogs.

Open-heart surgery using Del-Nido cardioplegia in two dogs: partial atrioventricular septal defect and mitral repair.

Del-Nido cardioplegia (DNc) is a single-dose cardioplegia that is widely used in human medicine because of its long duration. In this report, we describe two cases of open-heart surgery with cardiopulmonary bypass (CPB) using DNc. One dog was diagnosed with partial atrioventricular septal defect, and the other dog was diagnosed with myxomatous mitral valve disease stage D. Both dogs were treated with open-heart surgery with DNc to induce temporary cardiac arrest. No complications from DNc were observed, and the patients were discharged. Veterinary heart surgeons should consider DNc as an option for temporary cardiac arrest during open-heart surgery with CPB.

Electrical stunning of cattle.

Cattle are normally stunned electrically by three sequential cycles, first a three-second head-only cycle, to stun the animal, secondly a 15-second cardiac cycle, to induce ventricular fibrillation (cardiac arrest), and thirdly a four-second discharge cycle, to reduce convulsions after death. An effective and immediate stun was produced when > or =1.15 amps sinusoidal AC at 50 Hz was applied between the nose and neck electrodes for less than one second. However, when applied for three seconds, head-only currents of >0.46 amp sinusoidal AC at 50 Hz were sufficient to induce epileptiform activity in the brain, identified as high amplitude low frequency activity in the electroencephalogram. The induction of effective head-only electrical stunning resulted in an average interval of 50 seconds before the return of rhythmic breathing movements, and positive corneal and palpebral reflexes. The cardiac arrest cycle successfully induced ventricular fibrillation when >1.51 amps sinusoidal AC at 50 Hz was applied for five seconds between the nose and brisket electrodes.

[Possibilities and status of heart surgery in dogs]. / Möglichkeiten und Stand der Herzchirurgie beim Hund.

Before use of cardiovascular surgical techniques and procedures in humans, many experiments, e.g., hypothermic circulatory arrest and cardiopulmonary bypass using the heart-lung machine, have been performed in the dog. As a consequence experimental canine cardiovascular surgery is highly developed. This has not resulted in the routine performance of open heart surgery in veterinary medicine, probably because of the high costs. Cardiovascular surgery in the dog is generally limited to interventions not depending on hypothermic circulatory arrest or cardiopulmonary bypass. The clinical cardiovascular surgery in dogs can be divided into routine and more specialized interventions. The first category includes correction of peritoneopericardial diaphragmatic hernia, pericardial fenestration in dogs with pericardial effusion, treatment of persistent right aortic arch, and patent ductus closure. The specialized interventions include dilation of pulmonic and aortic stenoses and pacemaker implantation. The diagnosis and surgical treatment of such diseases is described. New developments in cardiovascular surgical treatment that can be expected include catheter techniques for occlusion of shunts and dilations using balloons, because the financial costs of these procedures are not prohibitive.

Circulatory arrest under hypothermic anesthesia using abdominal cavity cooling.

The purpose of this study was to investigate the potential for circulatory arrest during surgery under systemic hypothermic anesthesia, using the abdominal cavity cooling method. Eighteen beagles, each weighing 10.5 +/- 2.3 kg, were cooled by filling the abdominal cavity with crushed ice. Just after the esophageal temperature reached 30 degrees C, the heart was exposed, and a left-heart bypass from the left atrium to the aortic root was created. At 20-23 degrees C, the heart was arrested by infusing cooled Young's solution into the aortic root. After a period of cardiac arrest, resuscitation and rewarming were initiated simultaneously. Throughout these procedures, an electrocardiogram (ECG) and the arterial blood pressure (ABP) were monitored continuously. Hematocrit (Ht), total protein (TP), and arterial blood pH and gases were measured every 30 min. The recoveries after surgery were divided into three types as follows, 1) recovery without any complications-11 dogs, 2) not extubated with spontaneous breathing-4 dogs, 3) no reappearance of heart beat-3 dogs. PaO2 during resuscitation was significantly higher in dogs which recovered completely than in the rest of the dogs. These results suggest that hypothermia induced by the abdominal cavity cooling method could be useful for organ-protection during open-heart surgery, and that successful recovery may be attained through protection of the lung as well as the myocardium.

Open-heart correction of tetralogy of Fallot in an acyanotic dog.

Tetralogy of Fallot was diagnosed in an acyanotic 11-month-old dog. Predicted pressure gradient across the pulmonic valve, as assessed by use of continuous wave Doppler echocardiography, was 94.5 mm Hg. Bidirectional shunting was identified by means of selective angiography. Open-heart correction was performed, using a transatrial approach with limited ventriculotomy and cardiopulmonary bypass. The hypertrophied infundibulum was resected, the ventricular septal defect was closed primarily, and a transannular pericardial patch graft was applied. Pressure gradients across the pulmonic valve were 52.9 and 22.8 mm Hg 2 weeks and 4 months after surgery, respectively. Advances in cardiopulmonary bypass, anesthetic management, and use of the transatrial approach may improve the success of open-heart correction of tetralogy of Fallot in dogs.

Pig slaughtering procedures: time to loss of brain responsiveness after exsanguination of cardiac arrest.

The time taken for a conventional chest stick to produce the loss of flash-evoked responsiveness in the electrocorticogram of anaesthetised pigs was compared with a method involving fibrillation of the heart. On average severing the brachiocephalic trunk and anterior vena cava took 18 seconds to induce a loss of brain responsiveness, and inducing cardiac fibrillation took 19 seconds. It is concluded that a pig slaughtering method that stuns the brain and at the same time fibrillates the heart is likely to be more humane than the conventional slaughtering methods where there is a delay between the stunning and sticking operations.

Comparison of crystalloid and sanguineous cardioplegic solutions in the dog.

Myocardial protection provided by 2 types of cold cardioplegic solution and by cold saline solution was compared experimentally in dogs on cardiopulmonary bypass. Techniques and solutions used simulated clinical conditions. Serial biopsies of myocardium were assayed for adenosine triphosphate, adenosine diphosphate, and adenosine monophosphate. Maintenance and recovery of each phosphate was calculated as a percentage of the prebypass value for each type of solution; these values were used to compare the myocardial protection afforded by the 3 solutions. A difference in these values was not observed between the 2 types of cardioplegic solution; both values were greater than for the control solution, which may indicate improved myocardial protection with cardioplegic arrest.