Parathyroid response to hypocalcemia after treatment of hemorrhagic shock.

Hypocalcemia often follows resuscitation from hemorrhagic shock. The role of calcium supplementation is controversial, whereas, little data are available regarding the parathyroid (PTH) response. Therefore this response was studied in 41 injured patients who required 15 blood transfusions and 11.7 L balanced electrolyte solution during emergency room and operating room therapy. Postoperative reduced total calcium (7.5 +/- 0.8 mg/dl SD) and ionized calcium 1.85 +/- 0.2 mEq/SD) paralleled a rise in PTH (69.7 +/- 37 microliters Eq/ml SD) and the severity of insult as reflected by shock time and hypoalbuminemia. Renal function was normal. Increased PTH is probably homeostatic and belies the theoretical merits of calcium channel blocker administration after hemorrhagic shock. Calcium supplements may be of benefit during resuscitation when bone flow is low and calcium release from bone in response to PTH is reduced.