Use of a "heparin lock" in the intermittent administration of intravenous drugs. A technical advance in intravenous therapy

Successful Clearance of Catheter-Related Bloodstream Infection by Antibiotic Lock Therapy Using Ampicillin

Objective:

To report a case in which ampicillin was used successfully as lock therapy for a central venous intravascular catheter and to discuss the implications of ampicillin used in this modality.

Case Summary:

A 14-month-old girl with a long-term central venous catheter acquired a polymicrobial (Escherichia coli and Enterococcus durans) bloodstream infection. The central venous catheter was suspected as the source for the bacteremia based on the timing and number of positive blood cultures in relation to therapy with antibiotics. Antibiotic sensitivity testing revealed ampicillin monotherapy to be an ideal choice to treat both organisms. A combination of systemic therapy via a temporary catheter and antibiotic lock therapy of the central venous catheter was then instituted using ampicillin without anticoagulants. The patient tolerated this therapy without complications, and follow-up cultures demonstrated effective clearance of the bacteria.

Discussion:

Antibiotic lock therapy has been shown to be useful in the treatment of catheter-related bloodstream infections. However, many antibiotics have yet to be tested with this modality. Ampicillin, which is frequently used in the treatment of Enterococcus and E. coli infections, has not previously been reported as a single agent for lock therapy.

Conclusions:

Ampicillin may be a useful agent with the relatively new modality of lock therapy for central venous catheters. Further studies are needed to demonstrate possible compatibility of this agent with anticoagulants, such as heparin, as well as its efficacy in treating catheter-related bloodstream infections.

Approaches to the Treatment of Initial Pseudomonas aeruginosa Infection in Children Who Have Cystic Fibrosis

Pseudomonas aeruginosa remains an important cause of pulmonary disease in patients who have cystic fibrosis. The development of antimicrobial therapy directed against this organism has resulted in the preservation of lung function and improved longevity. Efficacy has been demonstrated with agents administered via parenteral, inhaled, and oral routes. The optimal antibiotic regimen remains unclear. There is an active effort to use randomized, controlled clinical trials to rigorously test effective antibiotic for the eradication of P aeruginosa in young children or at least to delay the establishment of chronic infection.

Heparin Locking for Central Venous Catheters

Traditionally, heparin-lock solution has been used with all central venous catheters. The introduction of new technology calling for the elimination of heparin and the growing concerns about the use of heparin have caused many health care professionals to question its continued use for this purpose. This literature review attempts to answer the most common questions using available research; however, there continues to be more questions than answers. At present, it appears that some farm of anticoagulant will produce more patent catheters, and heparin-lock solution is the only product commercially available. This situation drives the need for a careful assessment of patients' needs prior to abandoning the use of heparin.

Efficacy of normal saline injection with and without heparin for maintaining intermittent intravenous site

This study evaluated the effectiveness of normal saline versus normal saline containing 10 U per 1 mL heparin for preventing loss of an intermittent intravenous site (heparin lock). The sample consisted of 260 surgical patients from a general surgery and a cardiovascular surgery nursing unit at a tertiary care hospital. Results indicated that heparinized saline is not needed to maintain the patency of an intermittent intravenous site, and the use of saline solution alone is less irritating, causes less phlebitis, is less expensive to patients, and saves nursing time.

Is heparin really necessary in the lock and, if so, how much?

The literature on the issue of whether heparin is necessary in an intermittent peripheral venous access device (lock) is critically reviewed. Issues explored include loss of patency, development of phlebitis, duration of lock placement, type of cannula material, sample size, risk of toxicity with heparin flush solutions, risk of clot embolism, and physical or chemical incompatibilities. Available studies indicate that heparin is not necessary to maintain fluoroethylenepropylene (FEP-Teflon) peripheral venous access devices unless the lock is used to obtain blood specimens. Considering the benefit-to-risk ratio for the use of heparin, it is advisable to maintain FEP-Teflon locks with normal saline alone. When locks are used to obtain blood specimens, as in a pharmacokinetic study, then a dilute heparin flush solution should be used. Whether heparin is necessary for the maintenance of locks composed of other materials is uncertain. Newer, less thrombogenic materials such as ethylene tetrafluoroethylene may also obviate the need for heparin, but comparative trials in a larger number of patients are needed for confirmation. When heparin is used, an effort should be made to avoid systemic toxicities by using the lowest known effective concentration (10 units/mL) pending further studies.

Heparin lock intravenous line. Use in newborn infants. A controlled trial

The heparin lock technique has been available for parenteral access in older children and adults but has not yet been described for use in newborns. We randomized 39 newborns who needed parenteral medication in the intermediate care nursery to receive a heparin lock catheter (17) or an intravenous line kept patent by continuous low infusion rate (22). There were no differences between study groups with regard to birthweight, gestational age, or distribution of diagnoses. Infants in the heparin lock group were enrolled in the study on average 1 day longer than the continuous intravenous group (p less than 0.05). Subcutaneous infiltration occurred twice as frequently with the continuous intravenous line (p = 0.0015), and the life span was significantly less than heparin lock (1.0 +/- 0.5 days versus 2.1 +/- 1.0 days, p = 0.0003). Infants with continuous intravenous lines received approximately 20 ml/kg/day greater quantity of fluid (p less than 0.0001). There was no difference between groups with regard to mean heparin activity level. None of the infants developed hemorrhagic complications, thrombophlebitis, or documented nosocomial infection. Nurses significantly favored heparin locks over continuous intravenous lines for ease of use. The heparin lock technique is a safe and reasonable alternative to a continuous low infusion intravenous line for administering parenteral medications to intermediate care newborns.

Peripherally inserted central venous catheters for treatment of cystic fibrosis

Patients who have cystic fibrosis (CF) are frequently hospitalized for long-term intravenous (IV) treatment. We evaluated clinical effectiveness of the Drum-Cartridge Catheter (Abbott Laboratories) for such patients. The catheter is placed peripherally under local anesthesia via an antecubital vein into the superior vena cava or right atrium. Patients who were more than 10 years of age and who were hospitalized for IV antibiotic therapy and/or IV hyperalimentation were studied. All but 2 patients had CF. Using an aseptic technique the catheters were inserted into the basilic or cephalic vein. Chest radiographs were used to confirm the final location of the catheter. Catheters were used to administer IV antibiotics, hyperalimentation, and lipids. There were 38 catheterizations in 23 patients; several patients had repeated insertions at later admissions. The success rate of insertion was 86% with 31 of the 38 insertions initially located either in the superior vena cava or right atrium. Mean duration of catheterization was 15.4 days (range 5-49 days). No major complications such as sepsis, catheter or clot embolism, pneumothorax, vascular perforation, or hemorrhage occurred in the patients who had DF. Complications that required displacement of catheter into the axillary vein (1 patient), and cracked catheter hub (1 patient). This study shows that the Drum-Cartridge Catheter can be used easily for IV therapy of patients who have CF for a long duration, repeatedly, and with no major complications.

Dicarboxylic aminoaciduria: an inborn error of amino acid conservation

A 38-month-old apparently healthy male has been followed for three years because of a massive glutamic and aspartic aminoaciduria detected shortly after birth in a neonatal screening program. Amino acid clearance studies revealed the presence of renal wastage of dicarboxylic amino acids. Intestinal transport and in vitro oxidation of dicarboxylic amino acids were found to be intact. Clinical and metabolic data obtained on a previously described patient and the present case suggest that some patients with dicarboxylic aminoaciduria might have a selective renal conservation defect without clinical abnormalities, whereas others might demonstrate an additional defect in intestinal transport associated with fasting hypoglycemia.