Prediction of intravenous theophylline dosage based on a single, nonsteady-state concentration: a clinical study of childhood status asthmaticus.

A pharmacokinetic model was applied to achieve therapeutic serum theophylline concentrations rapidly in 25 children with status asthmaticus. A sustained release theophylline preparation had been taken within 36 hours by 12 children; within 14 hours, seven had taken an immediate release preparation; for six children, no theophylline was taken before hospital admission. Single serum theophylline concentrations were determined at nonsteady-state conditions within 13.

A system for individualized dosing of intravenous aminophylline using a programmable calculator.

A program that calculates a value of clearance for an individual patient prior to reaching steady state in the early stages of aminophylline therapy is presented. The program is written for the Texas Instruments TI-59 programmable calculator and may be used with or without the PC-100C printer. The program can provide clinically useful information concerning projected plasma concentrations prior to reaching steady state with an accurate history of the dose administration and serum concentration determination.

Heparin therapy for thromboembolic disorders. A prospective evaluation of 134 cases monitored by the activated coagulation time.

One hundred thirty-four patients with venous thrombosis or pulmonary embolism, confirmed by radiological techniques, received continuous-pump heparin therapy while their responses were monitored by the activated coagulation time (ACT). The suggested protocol was as follows: (1) give an intravenous bolus of about 50 units/kg; (2) follow with 15 to 25 units/kg/hr; (3) modify infusion rate to maintain ACT of 150 to 190 s; (4) after two or three days with ACT in target range, start oral warfarin sodium therapy; (5) after three to five days of warfarin therapy, if prothrombin time is two to 2 1/2 times the control value, discontinue heparin administration. One hundred thirty-two patients responded, with no heparin failures.

Adjusting heparin infusion rates from the initial response to activated coagulation time.

A mathematical description of the dose-response curve of heparin to the activated coagulation time is applied retrospectively to 20 patients treated with continuous heparin infusion. The adjusted heparin dose was compared with a calculated prediction using the theoretical mathematical model. The main actual dose was 28 U/kg/h, and the mean predicted dose was 25.

A calculator program to determine heparin requirements during hemodialysis.

A calculator program has been developed that will compute the sensitivity and clearance of heparin in a patient on hemodialysis prior to reaching steady state. The coagulation time at any time during the dialysis cycle may be determined. A rebolus dose or a duration of time to hold the infusion may also be calculated.

Sources of error in heparin therapy of thromboembolic disease.

We observed a series of patients with thromboembolic disease treated intravenously with heparin sodium and monitored by the activated coagulation time (ACT) of whole blood. When patients responded slowly, had dangerous hemorrhage, or had ACTs well outside our target range, we analyzed infusion records to determine actual infusion rates. We found the following sources of error: (1) lack of pump precision, (2) interruption of infusion, (3) errors in making up solutions, and (4) failure of infusion or charting techniques.