Central venous catheter related sepsis: a clinical review

Clinical signs of infection during continuous postoperative epidural analgesia in children: the value of catheter tip culture

BACKGROUND

Infection arising from the use of epidural catheters for postoperative analgesia is a major source of anxiety.

METHODS

The routine culture of epidural catheter tips were studied in 100 consecutive children aged 1 day to 15 years. Epidural catheters were inserted aseptically in accordance with an agreed protocol. The catheter site was inspected regularly and the tip sent for microbiological culture following removal.

RESULTS

Local signs of inflammation at the epidural site were seen in 16% of children, and bacteria were isolated from catheter tip culture in 32%. Positive catheter tip culture was found in 43% of children with local signs of inflammation and of the remaining children with no local signs, organisms were isolated from the catheter tip in 30%. Culture of skin swabs and catheter tips in two patients with purulent discharge at the epidural site yielded the same organism. No correlation between the number of attempts at catheter insertion and either local signs of inflammation or positive catheter tip cultures were found.

CONCLUSIONS

Minor local signs of inflammation and infection are common in pediatric patients during continuous epidural infusion. Epidural catheter tips are also frequently culture positive in patients with and without local signs and who may not go on to develop further signs or symptoms of infection. Routine culture of catheter tips is unnecessary as it is not a good predictor of epidural space infection.

Bacterial colonization and infection rate of continuous epidural catheters in children

Continuous epidural infusions are widely used for postoperative analgesia in children. We prospectively studied the incidence of bacterial colonization of caudal and lumbar epidural catheters, as well as the incidence of serious systemic and local infection, in 210 children after short-term epidural analgesia. Using aseptic technique, epidural catheters were inserted into either the lumbar or the caudal epidural space based on the preferences of the anesthesia team and/or clinical indication. The integrity of the catheter and overlying transparent dressing site was evaluated by a member of the pediatric pain service at least once a day. The catheters were aseptically removed if the patient had a fever greater than 39 degrees C, if the dressing was compromised, or when epidural analgesia was no longer required. The subcutaneous portion of the catheter was semiquantitatively cultured. Cellulitis (erythema, swelling, purulent discharge, pustule formation, or tenderness) was diagnosed by examination of the epidural insertion site. The mean (+/- SD) age of patients in the caudal catheter group (n = 170) was 3 +/- 3 yr; their mean weight was 13 +/- 11 kg. The mean (+/- SD) age of patients in the epidural catheter group (n = 40) was 11 +/- 4 yr; their mean weight was 36 +/- 23 kg. All catheters remained in place for 3 +/- 1 days (range 1-5 days). There was no serious systemic infection (meningitis, epidural abscess, or systemic sepsis). Of all epidural catheters, 35% (73 of 210) were colonized. Gram-positive colonization was similar in caudal (25%; 43 of 170) and lumbar (23%; 9 of 40) catheters. Gram-negative organisms were cultured from 16% of the caudal catheters (27 of 170) and 3% of the lumbar catheters (1 of 40). In patients treated with caudal epidural catheters, children aged >3 yr were less likely to have colonized epidural catheters than younger children. Age did not affect the probability of developing cellulitis at the insertion site. Although patients aged <3 yr with caudal catheters had a slightly greater risk of cellulitis than children aged >3 yr (14% vs 9%), this association was very weak (P = 0.33). We observed that, despite bacterial colonization of caudal and lumbar epidural catheters, serious systemic and local infection after short-term epidural analgesia did not occur in our study.

IMPLICATIONS

Continuous epidural infusions are widely used for postoperative analgesia in children. We found no serious systemic infections after short-term (3 days) continuous epidural analgesia in children.

Diagnosis of vascular catheter-related bloodstream infection: a meta-analysis

Catheter-related bloodstream infections increased in incidence during the past decade, causing significant morbidity, mortality, and excess hospital costs. Absence of inflammation at the catheter site in most cases makes clinical diagnosis uncertain. The relative accuracy and cost-effectiveness of different microbiologic tests for confirming that bloodstream infection is catheter related have remained unclear. A meta-analysis of published studies was conducted regarding the accuracy of diagnostic test methods using pooled sensitivity and specificity and summary receiver operating characteristic (ROC) curve analysis. The cost for each test was estimated by methods published by the College of American Pathologists. Costs of catheter replacement and antibiotic therapy for false positive results were included in the cost per accurate test result. Twenty-two studies evaluating six test methods met inclusion criteria for the meta-analysis. Accuracy increased in ROC analysis for catheter segment cultures with increasing quantitation (P = 0.03) (i.e., quantitative > semiquantitative > qualitative) largely due to an increase in specificity. The highest Youden index (mean = 0.85) was observed with quantitative catheter segment culture, the only method with pooled sensitivity and specificity above 90%. For blood culture methods, there was no statistically significant trend toward increased accuracy. The unpaired quantitative catheter blood culture offered the lowest cost per accurate test result but was only 78% sensitive. In conclusion, quantitative culture was the most accurate method for catheter segment culture, and unpaired quantitative catheter blood culture was the single most cost-effective test, especially for long-term catheters.