The beneficial role of calcium supplementation during resuscitation from shock.

The role of calcium (Ca) in resuscitation from hemorrhagic shock is controversial and in the present report three regimens were compared: supplementation (Ca-S), avoidance (No-Ca), and Ca channel blockade (Ca-B). This was studied in 40 splenectomized dogs subjected to reservoir shock (MAP 60 torr/90 min, then 40 torr/30 min) and treated with: a) 20 ml/kg balanced electrolyte solution (BES); b) shed blood; c) 30 ml/kg BES; and d) 250 ml autologous bank blood. Three groups of six dogs received Ca-S (0.5 mEq/kg), No-Ca, or Ca-B (verapamil 0.15 mg/kg) in BES. Postoperative therapy of 50 ml/kg/d BES with Ca-S, No-Ca, or Ca-B was given for 3 days. The effects of parathyroidectomy (P) via wide thyroidectomy in 22 dogs treated with calphosan (20 ml/d) and L-thyroxin (0.02 mg/kg) preceding shock was also studied as above: Ca-S/P, No-Ca/P, and Ca-B/P; four sham dogs had anesthesia but no shock (Anes/P). Studies done before, during, and after shock and on day three included systemic pressures (MAP), central pressures (CFP), cardiac output (CO), resistance (SVR), heart work (LVW), and outcome. Post-resuscitation Ca was significantly less in all groups (1.6-3.7 mg%) compared to Ca-S (4.8 mg%). Compared to Ca-S dogs, the post-resuscitation studies in the No-Ca and Ca-B dogs showed lower MAP, CO, and LVW in both intact and hypoparathyroid animals. Post-resuscitation CFP was also lower in the Ca-S and Ca-S/P dogs compared to the other euparathyroid and hypoparathyroid dogs. Death after the initiation of resuscitation occurred in two No-Ca/P and three Ca-B/P dogs. These data suggest that calcium supplementation plus an intact calcium-parathyroid axis enhance the resuscitation effort.