Incidence of bacterial contamination in infusion set needles.

We examined the incidence and types of bacterial contamination in 265 infusion set needles in adult critically ill patients. Bacterial contamination was detected in 15 samples (5.7%), and a total of 17 organisms were isolated. Ten were coagulase-negative staphylococci (CNS) and Staphylococcus aureus, and the remainder were α-Streptococcus, Corynebacterium, and gram-negative rods. Although the contamination was not directly related to catheter-related bloodstream infections exchanging infusion bottles can cause intraluminal contamination and is a possible route of these infections.

Comparison of bacterial contamination of blood conservation system and stopcock system arterial sampling lines used in critically ill patients.

BACKGROUND: Commonly placed to monitor blood pressure and to aspirate blood, arterial lines frequently cause complications. The blood conservation system (BCS) forms a closed infusion line and may be expected to reduce complications caused by intraluminal contamination. We compared microbial contamination resulting from use of BCS and 3-way stopcock catheterization. METHODS: Patients who required arterial catheterization for at least 24 hours in our intensive care unit were randomly assigned to receive an arterial pressure monitoring system either with the BCS (test group) or with a 3-way stopcock (comparator group). To evaluate arterial line contamination, we qualitatively assessed the contamination of the catheter tip and intraluminal fluid. RESULTS: We analyzed microbial contamination for a total of 216 arterial catheters: 109 in the test group and 107 in the comparator group. We found no difference in the incidence of catheter tip colonization in the 2 groups (test group, 8/109 vs comparator group, 11/107; P = .48). There was a statistically significant correlation between catheter tip colonization and duration of arterial line utilization. We found statistically significantly lower intraluminal fluid contamination in the test group (test group, 2/109 vs comparator group, 9/107; P = .03). There was no relationship between intraluminal fluid contamination and catheter tip contamination. CONCLUSION: There was less microbial contamination of intraluminal fluid when BCS was used for arterial catheterization.

Evaluation of errors influencing accuracy in image-guided neurosurgery.

Neurosurgeons sometimes find it difficult to locate tumors precisely during microsurgery, particularly tumors located in the brain parenchyma because of the absence of boundaries in this region. Image-guided neurosurgical techniques conducted with the help of neuronavigation systems have been developed and have gained importance recently. Accuracy is vital during image-guided neurosurgery. We used a phantom to evaluate the errors introduced during navigation. The three errors evaluated were skin-shift, marker-gap, and table-rotation errors. The skin-shift error occurs if the fiducial markers positioned on the scalp move when the head is fixed to a head holder with head pins. The marker-gap error occurs when the marker ball is positioned incorrectly in the marker socket. The table-rotation error occurs when the operating table is rotated for obtaining an intraoperative MR image and then returned to its original position. Our results indicated that skin shift decreased the navigation accuracy by an error of more than 4 mm, and the gap between the marker ball and the socket resulted in a decrease in navigation accuracy by an error of more than 5 mm. The table-rotation error was found to be negligible. The errors can be avoided by ensuring that the fiducial markers are positioned appropriately on the scalp and the marker ball is fitted well in the marker socket. A phantom is useful for evaluating accuracy, particularly for evaluating errors intrinsic to different operating rooms. Periodic quality assurance by use of a phantom in each operating room might aid in maintaining the accuracy of neuronavigation.