No abstract

No abstract

Anesthesiology and Veteran Affairs Anesthesiology, Durham, NC COLD AGGLUTININS (CA) are circulating autoantibodies that reversibly bind red blood cells, causing agglutination and increased blood viscosity. 1 Because cardiopulmonary bypass (CPB) can involve deliberate hypothermia of the systemic and coronary circulations, the adverse sequelae of CA have been feared and reported under such conditions. The authors present a case of successful perioperative management of a patient in whom CA activation was diagnosed after the initiation of CPB for coronary artery bypass grafting (CABG) and aortic valve replacement (AVR). This patient also had a stenotic coronary sinus (CS), adding to the complexity of management of CPB and administration of cardioplegia. Patient permission was obtained for the publication of this case report. DescriptionA 67-year-old man with moderate-to-severe aortic stenosis (mean gradient 36 mm/s) and multivessel coronary artery disease presented for CABG and AVR. Preoperative workup revealed preserved biventricular function with moderate left ventricular hypertrophy, 80% stenosis of the proximal left main coronary artery, and 99% stenosis of the proximal right coronary artery. He previously underwent an uneventful anesthetic for carotid artery bypass in preparation for his cardiac surgery. After placement of a radial artery catheter for pressure monitoring, anesthesia was induced with midazolam, fentanyl, lidocaine, propofol, and rocuronium. Aminocaproic acid was used for antifibrinolysis, with a 10-g bolus dose followed by a 5-g dose infused over 5 hours. Vein graft harvest and central aortic arterial and bicaval venous cannulation were uneventful.After an activated coagulation time of 4400 seconds was achieved, CPB was initiated. Because of CS stenosis (confirmed by the small ostial opening on transesophageal echocardiography [TEE]), a retrograde catheter could not be placed even under direct vision with bicaval cannulation (performed for better visualization of the coronary sinus ostia after the initial inability to cannulate). 2 Systemic perfusion was maintained at 361C inflow temperature, and the nasopharyngeal temperature approached a nadir of 351C.Before administration of cardioplegia, crystalloid cardioplegic solution (Plegisol; Hospira, Lake Forest, IL) was mixed with blood (4:1 ratio) and cooled to 4 1 C with a BCD Vanguard heat exchanger (Sorin, Milan, Italy). Within the tubing the blood separated rapidly, and large clumps of red cells were seen settling through the plasma in the tubing (Fig 1, Video 1). Because of the high index of suspicion, no cardioplegia was given, pending laboratory confirmation. A sample of blood was sent to the laboratory immediately for a rapid test for cold agglutinins. Specific cold agglutinin testing was not available immediately; however, a small amount of blood was cooled to 41C, and 4 þagglutination was observed. This information was relayed to the operating room so that the surgical plan could be altered. Subsequent testing revealed 2 þ agglutination a...

Several aspects of the methodology and interpretation of dual tracer measurements of blood volume have been investigated. A simple technique using autologous 31 Cr' chromated red cells and l25 I RIHSA is presented in detail. Accuracy and reproducibility have been assessed in duplicate studies in volunteers. Measured volumes have been compared with the volumes computed from standard prediction formulae.

Avoiding or managing hyperkalemia during cardiac surgery, especially in a patient with chronic renal insufficiency, can be challenging. Hyperkalemic cardioplegia solution is usually administered to achieve and maintain an electrical arrest of the heart. This solution eventually mixes in with the systemic circulation, contributing to elevated systemic potassium levels. Administration of packed red blood cells, hemolysis, tissue damage, and acidosis are also common causes of hyperkalemia. Current strategies to avoid or manage hyperkalemia include minimizing the volume of cardioplegia administered, shifting potassium from the extracellular into the intracellular space (by the administration of sodium bicarbonate when the pH is low and/or dextrose–insulin when effects relatively independent of serum pH are desired), using zero-balanced ultrafiltration (Z-BUF) with normal saline as the replacement fluid (to remove potassium from the body rather than simply shift the electrolyte across cellular membranes), and, occasionally, hemodialysis (1). We report the application of Z-BUF using an electrolyte-balanced, low potassium dialysate solution rather than isotonic saline to avoid a high chloride load and the potential for hyperchloremic acidosis to successfully treat hyperkalemia while on cardiopulmonary bypass.

Red cell volumes were measured immediately postoperatively and 2 hours later in five patients receiving solely stored blood as replacement for operative blood loss, and five patients receiving Macrodex as all or part of their replacement. In patients receiving solely bank blood the measured red cell volume increased about 10 per cent between the two measurements without any additional transfusion. In patients who had received Macrodex this phenomenon could not be demonstrated.

No abstract

The presence of cold agglutinins (CA) during cardiac surgery with cardiopulmonary bypass usually creates the need for an altered surgical plan. In this case, the CA were discovered after the initiation of bypass, limiting the time, and cardioplegia solutions that could be used in the new approach. The inability to cannulate the coronary sinus with a retrograde cardioplegia catheter excluded the standard approach to myocardial preservation with CA of using continuous warm blood. For this case, we used intermittent cold crystalloid delivered via the antegrade needle for the first half of the procedure and through the saphenous vein graft anastomosis during the aortic valve portion of the cross-clamp period.