S J Lukes

Central versus peripheral intravenous routes in cardiopulmonary resuscitation

The central venous (CV) and peripheral venous (PV) routes of drug administration are generally considered to be equally effective during cardiopulmonary resuscitation (CPR). This canine study compared simulated drug delivery via CV and PV routes during CPR. The CV group dogs had a CV catheter placed via the external jugular vein, and the PV group dogs had a PV catheter placed in the distal forelimb. Thirty seconds after the induction of cardiac arrest with KCl, CPR was begun with a gas-powered chest compressor with ventilations after every fifth compression. Sixty seconds later, a 0.5 ml bolus of technetium 99m-labeled serum albumin was given. Time activity curves were obtained over the right and left ventricles. The mean time for the counts to rise to half the left ventricular peak (T1/2LV) was significantly less for the CV group than for the PV group (P less than 0.05), averaging 11 and 84 seconds, respectively. The time to left ventricular peak (TLV) was also statistically shorter for the CV group than the PV group, averaging 118 versus 258 seconds, respectively. This study demonstrates that central venous administration is more rapid than peripheral venous administration during CPR and supports the preferential use of the central venous route for drug administration clinically.

Comparison of superior vena caval and inferior vena caval access using a radioisotope technique during normal perfusion and cardiopulmonary resuscitation

Recent studies of thoracic pressure changes during external cardiopulmonary resuscitation (CPR) suggest that there may be a significant difference in the rate of delivery of intravenous drugs when they are administered through the extrathoracic inferior vena cava (IVC) rather than the intrathoracic superior vena cava (SVC). Comparison of delivery of a radionuclide given using superior and inferior vena caval access sites was made during normal blood flow and during CPR. Mean times from injection to peak emission count in each ventricle were determined. There were no significant differences between mean peak times for SVC or IVC routes during normal flow or CPR. When peak times were corrected for variations in cardiac output, there were no significant differences between IVC and SVC peak times during normal flow. During CPR, however, mean left ventricular peak time, when corrected for cardiac output, was significantly shorter (P less than .05) when the SVC route was used. The mean time for the counts to reach half the ventricular peak was statistically shorter (P less than .05) in both ventricles with the SVC route during the low flow of CPR. This suggests that during CPR, increased drug dispersion may occur when drugs are infused by the IVC route and thus may modify the anticipated effect of the drug bolus. These results suggest that during CPR, both the cardiac output and the choice of venous access are important variables for drug delivery.

Incorporation of Patient Immobilization, Tissue Compensation and Matchline Junction Technique for Three-Field Breast Treatment

A protocol for the treatment of the intact breast was developed to maximize dose homogeneity and reproducibility. This protocol uses patient and breast immobilization, three-dimensional tissue compensators, and a technique for geometric matching of fields when the supraclavicular area is treated. A series of phantom measurements and analysis of patient port films was performed to evaluate dose homogeneity and reproducibility using this technique, and the potential adverse effect of loss of skin sparing from the immobilization device was investigated. Dose homogeneity throughout the phantom breast was within +/- 6% of the prescribed central axis dose, and homogeneity at the supraclavicular match line was +/- 10%. This represented a significant improvement over techniques not using tissue compensation or geometrically matched fields. Reproducibility of patient treatments was not significantly improved from previous non-immobilized treatment techniques, but there was no loss of skin sparing from the device, and other advantages of immobilization were observed. Details of the protocol are discussed together with changes that are currently being made to improve the results obtained thus far.

Effect of a pneumatic antishock garment on drug delivery via distal venous access

We examined the effect of an inflated pneumatic antishock garment (PASG) on simulated drug delivery through a distally placed venous catheter, during both normal flow and cardiopulmonary resuscitation (CPR). A PASG device was applied to anesthetized mongrel dogs and was inflated to 60 mm Hg. A small bolus of radionuclide was injected through an intravenous catheter placed distal to the PASG. Emission counts were made over both ventricles during conditions of normal flow and then during CPR following cardiac arrest. Mean times from injection to peak counts were determined. A control group of animals with central venous catheters but no PASG was studied similarly. There were no clinically appreciable differences between groups during normal flow. During CPR the PASG animals showed a mean delay of 90 seconds to the left ventricle peak. This difference was not statistically significant. We conclude that, in this canine model, acceptable delivery of drugs can be obtained by venous infusion into a limb with a PASG inflated.