Olga Schweizer

Massive Blood Replacement: Correlation of Ionized Calcium, Citrate, and Hydrogen Ion Concentration

Fifty-three patients were studied intraoperatively during massive transfusion of CPD-preserved blood and fresh frozen plasma (FFP). Baseline concentrations of total calcium (Ca), ionized calcium (Ca2+), albumin, total protein, and hydrogen ion concentration [H+] were measured prior to transfusion, at intervals during transfusion of 2500 ml of blood, and at the end of transfusion. Systemic arterial pressure (BPI, central venous pressure (CVP) and/or pulmonary artery wedge pressure (PAW), and corrected Q-T intervals on electrocardiographic tracings were measured at the time blood samples were obtained. Ca2+ decreased from 2.07 ± 0.03 mEq/L at baseline to 1.52 ± 0.05 mEq/L (p < 0.01) during transfusion at peak rates of 33 ± 3.2 ml/kg/hr. Following completion of transfusion, Ca2+ was significantly higher than at peak rates of transfusion, but still below baseline. Serum citrate levels rose from a baseline value of 1.87 ± 0.17 mg/dl to 6.30 ± 0.49 mg/dl (p < 0.01) at peak rate of transfusion and fell to 4.76 ± 0.48 immediately upon completion of transfusion (p < 0.011. The changes in Ca2+ and serum citrate levels showed a strong statistical correlation with each other. [H+] increased, but not significantly, at peak rates of infusion; after completion of transfusion, [H+] was significantly lower than during peak rates of transfusion. Ca levels were 4.10 ± 0.05 mEq/L at baseline, 3.90 ± 0.05 mEq/L at peak rates of infusion, and 3.89 ± 0.06 mEq/L after transfusion was completed. Albumin levels at the same sampling intervals were 3.60 ± 0.07, 3.71 ± 0.06, 3.87 ± 0.07 g/dl, respectively. Total protein levels were 5.95 ± 0.07, 5.67 ± 0.07, and 5.88 ± 0.09 g/dl, respectively. Corrected Q-T intervals were significantly prolonged at peak rates of transfusion and upon completion of transfusion. Correlation between changes in Ca2+ and corrected Q-T intervals was statistically significant. However, hemodynamic variables remained stable throughout the period of observation.Massive transfusions depressed Ca2+ due to administration of citrate, but this was only transient. Ca2+ rapidly returned to normal levels as citrate was redistributed and metabolized. The changes in Ca2+ were without hemodynamic significance. Clinically significant metabolic acidosis due to transfusion was not observed. We conclude, therefore, that as long as circulating volume is maintaines, as determined by measurement of CVP or PAW, calcium salts need to be administered during blood replacement, either empirically on the basis of rate or volume or transfusion, or on the basis of changes in samples indicate the development of metabolic acidosis.

A comparison of intraoperative measurements of coagulation.

The anesthesiologist often requires current information about the patients coagulation mechanisms. When hypocoagulability is suspected, information can be obtained with commercial clotting kits. Hypercoagulability and fibrinolysis can be detected rapidly only by the thrombe-lastograph.

Calcium chloride administration in normocalcemic critically ill patients.

Ten normocalcemic critically ill patients who had experienced a decrease in cardiac index ≥0.5 liter/min/m2 after incremental changes of PEEP received 7 mg/kg of CaCl2 as a slow iv bolus, followed by an infusion of 20 mg/kg CaCl2 over 60 min. Hemodynamic pressures and flow, oxygen uptake and transport, and blood chemistry variables were determined over a 120-min period. The results indicated that: (1) hemodynamic variables were not affected except for left ventricular stroke work index and mean blood pressure, which increased slightly; (2) both serum calcium and ionized calcium concentrations increased significantly, sometimes to dangerous levels; (3) colloid osmotic pressure and hemoglobin levels decreased slightly but consistently. In conclusion, CaCl2 administration failed to improve hemodynamic function depressed by PEEP. If CaCl2 can play a relevant role in the management of cardiovascular depression, further identification of appropriate doses and patients is necessary.

The Effect of Ether and Halothane on Blood Levels of Glucose, Pyruvate, Lactate and Metabolites of the Tricarboxylic Acid Cycle in Normotensive Patients During Operation

Arterial blood samples were studied for hematocrit, oxygen saturation, PaO2 acid base balance, glucose, pyruvate, lactate, excess lactate, citrate, α-ketoglutarate, malate, acetyl coenzyme A and adenosine triphosphate in adult patients anesthetized with ether or halothane-nitrous-oxideoxygen. All types of operations except cardiovascular, neurological and obstetrical were included. No deviations from standard anesthetic or fluid replacement methods were employed except the substitution of saline for dextrose solutions. There was no evidence of shock in any case. Significant variation between anesthetic agents occurred in only 3 parameters. End of operation samples showed levels of total lactate, pyruvate and excess lactate consistently higher with ether than with halothane-nitrous-oxide-oxygen. Total acid increase was also greater with ether. Blood levels of acetyl coenzyme A and the three acids of the tricarboxylic acid cycle were not influenced by type of anesthetic agent or the presence or absence of excess lactate. Lactate levels over 3 mEq./liter were associated with decreased blood levels of adenosine triphosphate, an effect more marked with ether than halothane. One possible explanation for higher lactate levels with ether is based on the sympathomimetic action of the agent A second, hypothetical explanation, suggests a depressant effect of ether on the intramitochondrial electron transport chain or the shuttle systems for transfer of reducing equivalents across the milochondrial membrane.

PROGNOSTIC SIGNIFICANCE OF HIGH LACTATE LEVELS

REVIEW of, 248 patients in whom lactate, A pyruvate, acid-base balance and other parameters were investigated revealed no mortality in 158 cases with arterial lactate levels < 3 mEq./L., 1 death in 48 patients with lactate levels ranging from 3 to 5 mEq./L., and 13 deaths in 42 patients with lactate values over 5 mEq./L. The significantly higher mortality associated with elevated levels of lactate confirms the observations of Waters and associates,l Daughaday and coworkers,2 H~ckabee,~ p 4 Tranquada’s group,5 and Bernier and associates,6 who described fatal metabolic acidosis attributable to excessively high levels of lactic acid.

ESTIMATION OF ACID‐BASE OF VENOUS AND ARTERIAL BLOOD FROM CAPILLARY SAMPLES

Comparisons were made between acid‐base values obtained from arterial, ear‐lobe, finger‐pulp and venous blood. Statistical analysis of the results indicated that samples obtained from the ear lobe could be used to estimate the acid‐base parameters of arterial blood in the absence of any autonomic upset in the anesthetized patient.

Intraoperative physiologic monitoring and management during hepatic lobectomy using the liver isolation-perfusion technic

The high operative mortality of major hepatic resection for tumor can be improved by a technic of resection using complete vascular isolation and hypothermic perfusion of the liver. Complete clamping of the portal vein, vena cava, and hepatic artery was necessary and well tolerated. Major physiologic, biochemical, and coagulation changes, however, can occur with this technic that requires close monitoring by the anesthesiologist. With astute observation and prompt corrective measures when indicated, these changes can be minimized to enable a safe and smooth resection to be carried out.

Effect of lactated ringer's solution on glycolysis.

HIRES and associates,lJ McClelland’s S group,3 Trudnowski and coworkers,I and Dillon and associates5 have advocated administration of large volumes of lactated Ringer’s solution as replacement therapy during operation and in hemorrhagic shock. The rationale for the use of lactated Ringer’s solution is based on observations of the Shires group that major surgery and massive blood loss are associated with an acute reduction of extracellular fluid stores.

Fibrinogen and albumin deficiencies associated with packed red blood cell transfusions.

Fibrinogen content was determined for each of 50 units of citrate-dextrose-phosphate (CPD)-preserved whole blood, packed red blood cells reconstituted with 250 ml. of saline, and packed red cells reconstituted with 250 ml. of purified plasma protein fraction (PPF). The total protein and albumin were measured, by electrophoresis, on each of 10 units of the three varieties of blood. The fibrinogen content of the two types of reconstituted cells was significantly lower than that of whole blood. Although the total protein/albumin content of whole blood and PPF-reconstituted red cells was similar, saline-reconstituted cells were markedly deficient in both total protein and albumin. Low fibrinogen and platelet levels subsequent to transfusion with reconstituted packed red cells can lead to an erroneous diagnosis of disseminated intravascular coagulation. Administration of large quantities of saline-reconstituted packed cells could be an etiologic factor in postoperative interstitial pulmonary edema.

FACTORS INFLUENCING THE IONIZATION OF CALCIUM DURING MAJOR SURGICAL PROCEDURES

The existence of a clinically feasible calcium electrode makes it possible to obtain rapid, accurate levels of ionized calcium. It is now possible to study the actual ionization of calcium under normal and abnormal physiologic conditions. The present investigation was directed at changes in ionized calcium during major surgical procedures. The total series of 125 patients was divided into three groups according to the type of plasma volume expander: group 1, whole blood alone; group 2, whole blood plus exogenous albumin, and group 3, albumin alone. Ionized calcium levels dropped significantly, p less than 0.001, in all three groups. Although albumin alone produced a decrease in ionized calcium, the addition of albumin to whole blood did not result in a greater decline than that experienced with whole blood alone. Chelation with the citrate ion of bank blood preservative was the major factor responsible for the decrease in ionized calcium. There was no statistically significant relationship between the extent of the decrease, the total volume of blood, the volume of blood per kilogram of the rate of transfusion in milliliters per kilogram per minute. Although the ionized calcium level fell initially, it increased while blood administration continued. In view of these facts, it is difficult to estimate the acutal level of ionized calcium at any point during the operation. Twenty patients in the series had ionized calcium levels below 1.25 milliequivalents per liter, range of 0.51 to 1.24 milliequivalents per liter. With the possible exception of one patient, no adverse cardiovascular effects could be attributed to the low levels of ionized calcium. The results in this series confirm our previous conclusion that the administration of exogenous calcium is not necessary during massive transfusion, with the possible exception of bypass open heart procedures and exchange transfusions in children.