Retrograde cerebral perfusion during profound hypothermia and circulatory arrest in pigs.

The purpose of this study was to evaluate the use of retrograde cerebral perfusion via the superior vena cava during profound hypothermia and circulatory arrest (CA) in pigs. In three groups of 5 pigs each, group A (control) underwent cardiopulmonary bypass and normothermic CA for 1 hour, group B underwent cardiopulmonary bypass, profound hypothermia, and CA (15 degrees C nasopharyngeal) for 1 hour, and group C underwent the same procedure as group B plus retrograde cerebral perfusion. In group A none awoke. In group B, 2 of 5 did not awake and 3 of 5 awoke unable to stand, 2 with perceptive hind limb movement and 1 moving all extremities. In group C all awoke, 4 of 5 able to stand and 1 of 5 unable to stand but moving all limbs. In neurologic evaluation group B had significantly lower Tarlov scores than group C (p = 0.0090). Group B mean wake-up time, plus or minus standard error of the mean, was 124.6 +/- 4.6 minutes versus 29.2 +/- 5.1 in group C (p = 0.0090). In group B late phase CA cerebral blood flow dropped 30.9% +/- 4.8%, but in group C it rose 24.7% +/- 9.3% (p = 0.0007, pooled variance t test, two-tailed). In group B late phase CA brain oxygenation decreased 46.0% +/- 13.9% but it increased 26.1% +/- 5.4% in group C (p = 0.0013). This difference was reduced somewhat during rewarming (B, -21.2% +/- 14.9%; C, 16.4% +/- 4.7%; p = 0.043). Group B rewarming jugular venous O2 saturation was 30.8% +/- 2.5% versus 56.0% +/- 4.4% in group C (p = 0.0011). We conclude that in pigs retrograde cerebral perfusion combined with profound hypothermia during CA significantly reduces neurologic dysfunction, providing superior brain protection.

Limiting homologous blood exposure.

Successful limitation of homologous blood transfusion may necessitate multiple strategies and advance planning. Preoperative and intraoperative autologous blood collection may have to be supplemented with hemostatic pharmacologic agents. The use of cytokines is increasing. More efficient use of directed donors can have an important role in blood use. As these expensive and time-consuming techniques become available, a major challenge will be to determine which patients may benefit from or really need them.

Pulmonary calcification in long-term hemodialysis: a mimic of pulmonary thromboembolism.

Metastatic pulmonary calcification is a frequent complication of chronic renal failure, especially in patients undergoing maintenance hemodialysis. We report a patient with chronic renal failure, who developed chest pain and hypoxia suggestive of pulmonary thromboembolism (PTE) and subsequently died. The ventilation/perfusion (V/Q) scan was also interpreted as consistent with PTE. At autopsy the areas of reduced perfusion on the scan corresponded to the areas of pulmonary calcification with no evidence of PTE. Physicians should be aware that this condition may mimic PTE, and that pulmonary angiography may be necessary to confirm the diagnosis prior to the initiation of anticoagulation.