Celestine Harrigan

Significance of Hypocalcemia following Hypovolemic Shock

Changes in calcium levels during and after resuscitation from severe shock were studied in 22 seriously injured patients who received an average of 21 blood transfusions and 26 mEq supplemental calcium. Total serum proteins (TSP), serum albumin (SA), total calcium (TC), and ionized calcium (CA++), were studied intraoperatively after the tenth transfusion and postoperatively at 5 hours, 15 hours, day 2, day 4, and during convalescence (day 25). The intraoperative TSP fell to 3.7 gm%; the TC and Ca++ fell to 7.2 mg% and 1.4 mEq/L. The TSP and SA remained low throughout day 4 (4.8 and 2.6 gm%); the TC was also low on day 4 (7.5 mg%), whereas the Ca++ rose to normal (2.1 mEq/L) by day 2. The severity of hypocalcemia paralleled the hypoproteinemia, the number of transfusions given during resuscitation, and the duration of shock; paradoxically, hypocalcemia correlated inversely with Ca++ supplementation of blood transfusions during resuscitation, suggesting increased extravascular Ca++ flux with more severe shock. Further studies in comparably injured patients are needed to identify the concomitant responses of the calcium homeostatic factors such as parathormone in order to help identify the optimal role of calcium manipulation during resuscitation from hypovolemic shock.

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.

Spatulated versus end-to-end anastomosis for small vessel injury

Spatulated anastomosis (SA) was compared to end-to-end anastomosis (EEA) with small arteries (3-4 mm) in nine conditioned dogs (22-30 kg). A 1-cm segment of both common femoral arteries with an average of 3.5-mm external diameter was resected and reconstructed by EEA and by contralateral SA using a running suture of 5/0 proline. Pre- and postoperative flow rates, flow rates at 1 year in three dogs, arteriography at 1 year in six dogs, and gross examination at 1 year were done. The preoperative flow rates averaged 86 ml/min for the SA and 76 ml/min for the EEA; early postoperative flow rates averaged 100 ml/min and 92 ml/min, respectively, whereas 1-year flow rates averaged 63 ml/min and 57 ml/min, respectively. None of these differences is significant. Preoperative and 1-year external diameters averaged 3.54 mm and 3.39 mm in the SA group compared to 3.5 mm and 3.44 mm in the EEA group. Arteriograms showed good flow except for slight narrowing in one SA which, on postmortem exam, was seen to result from a fibrous band which extended from the spatulated segment to the opposite wall. These data show that SA and EEA yield comparable results both acutely and long term. The choice of EEA versus SA for primary repair of injured small vessels should be determined by surgical preference.