ABSTRACT
The correlation between serum ionized calcium (Ca++) levels and three ECG QT intervals (Q-OTC, Q-ATC, and Q-ETC) was assessed in 20 adult patients. The relationship between each QT interval and Ca++ level, based on 209 Ca++ determinations through a range of 1.0 to 4.0 mEq/liter, is best described by a hyperbolic function. Although Q-OTC and Q-ATC predict Ca++ levels more accurately than Q-ETC, all QT intervals are clinically unreliable as guides to the presence of hypercalcemia. Similarly, the usefulness of the QT intervals in the diagnosis of hypocalcemia is limited by the wide distribution of normal values.
Subject(s)
Calcium/blood , Electrocardiography , Hypercalcemia/diagnosis , Adult , Blood Transfusion , Humans , Hypocalcemia/diagnosis , Preoperative CareSubject(s)
Hypothermia , Coronary Vessels/surgery , Diagnostic Errors , Electrocardiography , Humans , Hypothermia/diagnosis , Ischemia/diagnosis , Male , Middle AgedABSTRACT
In anaesthetized patients, administration of citrated whole blood for 5 min at controlled rates of 50, 100 and 150 ml/70 kg/min resulted in decreases in the calcium ion concentration (Ca2+) of 14, 31 and 41%, respectively. Ca2+ returned rapidly to the control values after termination of the transfusion. Reciprocal changes in serum citrate concentrations occurred, suggesting that the transient hypocalcaemia was a result of redistribution of citrate and hepatic or renal clearance from the vascular space. The total serum calcium concentration did not change significantly during rapid blood administration. Normal saline infusion at 100 ml/70 kg/min caused no change in Ca2+; however, plasma protein administration at this rate resulted in an 18% decrease in Ca2+, presumably as a consequence of the binding of calcium ions to anionic sites on plasma protein. Hypocalcaemia accompanying blood transfusion is a transient phenomenon, dependent on the total dose of citrate administered and the rate of infusion. Rational calcium replacement therapy during massive blood transfusion may now be based on direct Ca+ measurement.
Subject(s)
Hypocalcemia/etiology , Transfusion Reaction , Anesthesia , Calcium/blood , Citrates/blood , Clinical Trials as Topic , Humans , Infusions, Parenteral , Kidney/metabolism , Liver/metabolism , Potassium/blood , Time FactorsABSTRACT
Rapid transfusion of citrated whole blood was associated with acute hypotension and a rising central venous pressure in a patient undergoing pelvic exenteration and hemipelvectomy. Evidence of cardiac failure was accompanied by a precipitous decrease in serum ionized calcium (Ca++) concentration. When the rate of blood transfusion was slowed, arterial blood pressure returned to the control level and serum Ca++ increased.
Subject(s)
Heart Diseases/etiology , Hypocalcemia/etiology , Transfusion Reaction , Adult , Anesthesia, Intravenous , Blood Gas Analysis , Blood Pressure , Carcinoma, Squamous Cell/surgery , Female , Humans , Preanesthetic Medication , Ureteral Obstruction/surgery , Uterine Cervical Neoplasms/surgeryABSTRACT
Calcium chloride (7 mg/kg) was administered intravenously to six healthy volunteers anesthetized with halothane. Cardiovascular changes were measured during constant ventilation and anesthetic depth under three conditions: 1) respiratory alkalosis, 2) normocarbia, and 3) respiratory acidosis. At each Paco2, calcium infusion significantly increased cardiac index, left ventricular minute work index, and stroke index. Heart rate, total peripheral resistance, and cardiac pre-ejection period decreased. No significant change in mean arterial blood pressure or central venous pressure followed calcium administration, and no arrhythmias occurred. It is concluded that calcium administration increases myocardial performance, presumably by increasing the availability of intracellular calcium ion for actomyosin interaction.
