The confounding effects of pharmacokinetics and pharmacodynamics of sedatives and opioids on time to death after terminal withdrawal of life-support in the intensive care unit.

Drs. Schulz-Stübner and Schummer are correct in that we did not mention electrocardiogram positioning as a tool to verify correct positioning of a central venous catheter (CVC). However, our goal was to increase awareness of how to prevent CVC-induced cardiac tamponade by positioning the CVC tip outside the pericardial reflection. Electrocardiogram-guided CVC positioning places the CVC tip at the sinoatrial node, near the cava-atrial junction. Left in this position, the tip of the CVC will be inside the pericardial reflection and the CVC tip must be withdrawn an additional 2 cm for final proper positioning. Therefore, this technique is not superior to other techniques nor does it spare chest radiograph. Personally, after reading the report by Kim et al., I position the tip of any right-sided CVC at 11 to 12 cm depth and left-sided CVC at 12 to 13 cm. Proper positioning outside pericardial reflection was proved by chest radiographs in all cases. This approach spares unnecessary use of expensive equipment with the same patient benefit.