Intravenous arginine-vasopressin in children with vasodilatory shock after cardiac surgery.

BACKGROUND: Recent investigations at our institution have studied a variety of vasodilatory shock states that are characterized by vasopressin deficiency and pressor hypersensitivity to the exogenous hormone. Our experience in adults prompted the use of arginine-vasopressin (AVP) in a similar group of critically ill children. METHODS AND RESULTS: This report describes our early experience (from February 1997 through April 1998) in 11 profoundly ill infants and children (5 male, 6 female) ages 3 days to 15 years (median, 35 days) treated with AVP for hypotension after cardiac surgery which was refractory to standard cardiopressors. Although underlying heart disease was present (congenital heart defects in 10 and dilated cardiomyopathy in 1), only 2 patients had severely depressed cardiac function as demonstrated by 2D echocardiogram before administration of AVP. All patients were intubated and receiving multiple catecholamine pressors and inotropes, including dobutamine (n=10), epinephrine (n=8), milrinone (n=7), and dopamine (n=4) before receiving AVP. Five patients received AVP intraoperatively immediately after cardiopulmonary bypass, 5 in the intensive care unit within 12 hours of surgery, and 1 on postoperative day 2 for hypotension associated with sepsis. The dose of AVP was adjusted for patient size and ranged from 0.0003 to 0.002 U. kg(-1). min(-1). During the first hour of treatment with AVP, systolic blood pressure rose from 65+/-14 to 87+/-17 mm Hg (P<0. 0001; n=11), and epinephrine administration was decreased in 5 of 8 patients and increased in 1. Plasma AVP levels before treatment were available in 3 patients and demonstrated AVP depletion (median, 4.4 pg/mL; n=3). All 9 children with vasodilatory shock survived their intensive care unit stay. The 2 patients who received AVP in the setting of poor cardiac function died, despite transient improvement in blood pressure. CONCLUSIONS: Infants and children with low blood pressure and adequate cardiac function after cardiac surgery respond to the pressor action of exogenous AVP. AVP deficiency may contribute to this hypotensive condition.

Lack of lipid involvement in nonosseous tissue repair.

Calcium-acidic phospholipid-phosphate complexes (Ca-PL-PO4) have been implicated in the onset of tissue mineralization in healing fracture callus as well as in normal osteogenesis. Although these complexes are not found in nonmineralizing normal tissues, the possibility that they are more involved in healing phenomena than in actual mineralization cannot be excluded. The present study confirms that Ca-PL-PO4 complexes are only involved with osseous repair. In healing skin at 5, 8, and 11 days after wounding, Ca-PL-PO4 concentration was not significantly elevated (percentage complexed lipid P/total lipid P: 3.7, 2.4, and 3.8, respectively) relative to the value found for normal skin (2 +/- 2%), although the total lipid phosphorus content at 8 and 11 days was increased.

Phospholipid changes in the bones of the vitamin D-deficient, phosphate-deficient, immature rat.

The epiphyseal (cartilage) and diaphyseal (bone) regions of the long bones of vitamin D-deficient, phosphate-deficient, immature rats have been shown to contain Ca-PL-PO4 complexes in amounts comparable to that found in normal rat bones. This suggests that these calcium acidic phospholipid complexes are formed prior to mineralization. The metaphysis (bone and calcified cartilage) of the experimental animals contained less Ca-PL-PO4 than control bone, which suggests that Ca-PL-PO4 content is elevated as mineralizing activity increases. Overall bone lipid composition was dependent on the vitamin D status of the animals. Total lipid, cholesterol, and cholesterol ester content was higher in experimental animals than in controls. In contrast, free fatty acid and lysophosphatide were lower in experimental than in control animal's bones. The total phospholipid content (based on organic phosphate analyses) was unaltered by the vitamin D status. These lipid changes, reminiscent of changes seen in the intestinal brush border membrane of rachitic animals, suggest that vitamin D effects on lipid metabolism in bone may be similar to those in the intestine.