Heparin-coated Catheter Research Articles

Sorption of isosorbide dinitrate to central venous catheters.

As several studies demonstrated the sorption of isosorbide dinitrate (ISDN) to intravenous delivery systems, a study on the sorption of ISDN to several central venous catheters was performed. Fourteen different catheters were perfused during a 2 h period, under simulated infusion conditions, with ISDN (250 micrograms mL-1) in 0.9% (w/v) sodium chloride. The drug loss to a polyethylene and a silicone catheter was 0.2 and 6.1%, respectively. The sorption to a polyvinylchloride heparin-coated thermodilution catheter was 1-6.9% depending on the length of the catheter. The drug loss to polyurethane catheters of different composition varied between 3.8 and 28.9%. For polyurethane catheters composed of cycloaliphatic polyurethanes an inverse relation was shown between Shore A hardness and sorption.

Permanent catheterization of the carotid artery induces kidney infection and inflammation in the rat

Catheterization of the carotid artery and the jugular vein is one of the most commonly applied techniques used to gain intravascular access in pharmacology studies on rodents. We catheterized 10 rats by conventional clean techniques, 10 rats by aseptic techniques and 10 rats by conventional clean techniques using a heparin-coated catheter rather than an ordinary non-coated polyvinyl chloride catheter. In all groups, approximately 80% of the rats developed kidney infection and 10-30% of the rats were septicaemic. Clinical chemistry did not indicate severe kidney damage, but serum haptoglobin and body temperature rises indicated an inflammatory response in rats independent of the surgical method. Heparin coating did not seem to improve the usability of the catheter. It is concluded that this commonly used method for catheterization has an impact on animals that may very well render them unsuitable for the purpose, e.g. pharmacological research, and therefore an alternative method would be preferable.

Comparison of Heparin-Coated and Conventional Split-Tip Hemodialysis Catheters

Catheter coatings have the potential to decrease infection and thrombosis in patients with chronic dialysis catheters. We report our midterm experience with a heparin-coated dialysis catheter. This retrospective, case-control study was approved by our Institutional Review Board. A total of 88 tunneled dialysis catheters were inserted over a 13-month period via the internal jugular vein. Thirty-eight uncoated split-tip catheters and 50 heparin-coated catheters were inserted. Primary catheter patency was compared between the two groups using the log rank test, with infection and/or thrombosis considered as catheter failures. Dialysis parameters during the first and last dialysis sessions, including pump speed, actual blood flow, and arterial port pressures, were compared using unpaired t-tests. Primary patency of the uncoated catheters was 86.0 +/- 6.5% at 30 days and 76.1 +/- 8.9% at 90 days. Primary patency of heparin-coated catheters was 92.0 +/- 6.2% at 30 days and 81.6 +/- 8.0% at 90 days (p = 0.87, log rank test). Infection requiring catheter removal occurred in four patients with uncoated catheters and two patients with heparin-coated catheters (p = 0.23). Catheter thrombosis requiring catheter replacement or thrombolysis occurred in one patient with an uncoated catheter and two patients with heparin-coated catheters (p = 0.9). No differences in catheter function during hemodialysis were seen between the two groups. In conclusion, the heparin-coated catheter did not show a significantly longer patency compared to the uncoated catheter. The flow characteristics of this device were comparable to those of the conventional uncoated catheter. A demonstrable benefit of the heparin-coated catheter in randomized trials is needed before a recommendation for routine implementation can be made.

The use of non-primed peripheral and central IV tubings for nesiritide infusion is reliable and cost-effective

Background: Prescribing information of nesiritide mandate 25 mL priming of IV tubings, prior to connecting to pt's IV access, since the drug may partially absorb to the line. Thus, 1/10 of reconstituted vial is wasted, with a cost of $40–50 per line used. No study quantified binding effect of IV tubings, nor tested binding properties of different materials, nor analyzed binding effect of central lines, where priming cannot occur. Furthermore, prescribing information state that nesiritide must not be administered through a central heparin-coated catheter, since it may bind to heparin. However, no study quantified this binding effect. Methods: 1.5 mg vials of nesiritide were reconstituted into 250 mL 0.9% NS IV bags. 23.3mL bolus, followed by 7mL/h 2-hour infusion (2ug/kg bolus, 0.01ug/kg/min infusion for a 70kg pt) were run, in duplicate, through: 1) Standard PVC peripheral IV tubing primed with a 25 mL of nesiritide; 2) Standard non-primed PVC peripheral IV tubing; 3) Non-primed polyethylene peripheral IV tubing, commonly used for NTG infusion; 4) Non-primed PVC peripheral IV tubing, connected distally to a central IV polyurethane catheter; 5) Non-primed PVC peripheral IV tubing, connected distally to a heparin-coated pulmonary artery PVC catheter. Nesiritide concentration was measured, in triplicates, in the IV bags and samples collected from the five IV settings, using Biosite BNP test (Beckman Coulter). Results: CV for duplicate experiments was 3.4%. At least 95% of nesiritide was recovered from all five IV settings. Priming of PVC tubings with nesiritide improved drug recovery by 2% during IV bolus and 2-hour infusion compared to non-primed PVC tubings. Polyethylene tubings improved drug recovery also by 2% at 1- and 2-hour time points, suggesting that polyethylene saturates faster than PVC. Connecting a triple lumen or heparin-coated pulmonary artery catheter distally to non-primed PVC tubings did not further impact percentage of drug recovery. Conclusions: Priming of peripheral IV tubings with 25mL of nesiritide minimally improves drug release to pts, since>95% of drug is delivered even without priming. Polyethylene IV tubings further minimize drug binding and offers an even more reliable, yet inexpensive, alternative to priming. Elimination of priming may result in $40–50 saving per line used. Use of central lines or heparin-coated pulmonary catheter does not result in significant binding. Thus, changes in nesiritide prescribing information are warranted.

The Use of Non-Primed Peripheral and Central IV Tubing for Nesiritide Infusion is Reliable and Cost-Effective

Background Prescribing information of nesiritide mandates priming of intravenous tubing with 25 mL of nesiritide prior to connecting the intravenous (IV) line to the patient, since the drug may partially absorb to the line. Thus, 10% of a reconstituted vial is wasted, with a cost of $40-50 per line used. No study has quantified the binding effect of nesiritide to intravenous tubing, tested binding properties of different materials, or analyzed binding effect of central lines, where priming cannot occur. Furthermore, prescribing information states that nesiritide must not be administered through a central heparin-coated catheter, since it may bind to heparin. However, no study quantified this binding effect. Methods 1.5 mg vials of nesiritide were reconstituted into 250 mL 0.9% NS bags. A 23.3mL bolus, followed by 7mL/h 2- hour infusion (2ug/kg bolus, 0.01ug/kg/min infusion for a 70kg pt) were run, in duplicate, through 5 separate experimental tubing systems: 1) Standard PVC peripheral IV tubing primed with a 25 mL of nesiritide; 2) Standard non-primed PVC peripheral IV tubing; 3) Non-primed polyethylene peripheral IV tubing, commonly used for NTG infusion; 4) Non-primed PVC peripheral IV tubing, connected distally to a central IV polyurethane catheter; 5) Non-primed PVC peripheral IV tubing, connected distally to a heparin-coated pulmonary artery PVC catheter. Nesiritide concentration was measured, in triplicate, in the initial bags and samples collected from the five IV settings, using Biosite BNP test (Beckman Coulter). Presented at 2004 Heart Failure Society of America – Eighth Annual Scientific Meeting

Antibiotic Administration in an Animal Model of Chronic Peritoneal Dialysate Exposure

♦ Objectives The high incidence of intraperitoneal infection remains an important problem in animal models of chronic dialysate exposure. Prophylactic antibiotic administration can be used to resolve this problem, but the isolated effects of antibiotics on peritoneal membrane function and structure are unknown. The present study examined the effects of prophylactic antibiotics on infection rate and peritoneal membrane function and structure in a rat model of chronic dialysate exposure. ♦ Design A first group of rats (A; n = 12) received 10 mL 3.86% glucose dialysate twice daily through a heparin-coated catheter. In a second group of animals (B; n = 12), oxacillin 2.5 mg/day and gentamicin 0.04 mg/day were added to the dialysate. Group C ( n= 12) was injected twice daily with an identical dose of antibiotics dissolved in 1 mL of buffer solution. Group D ( n = 12) was left untreated. Dialysate cultures were obtained regularly. After 8 weeks of exposure, peritoneal transport studies were performed and samples for histology were obtained. ♦ Results Technique survival was 92% in group A and 100% in the remaining groups. Five rats in group A but none of the animals in the other groups developed peritonitis. The transport rates of small solutes were elevated and net ultrafiltration was decreased in group A compared to the controls. Fibrosis, as evaluated by quantifying Picro Sirius Red staining with image analysis, was significantly elevated in group A (3.48% ± 1.06% vs 0.72% ± 0.51% in group D, p < 0.05) but not in group B (0.29% ± 0.07%) or in group C (0.52% ± 0.28%). Vascular density, measured by counting the number of blood vessels that stained positive for endothelial NO synthase, was increased in both groups that were exposed to dialysate: 153.0 ± 12.9/μm2 in group A and 131.6 ± 14.3/μm2 in group B, versus 76.76 ± 12.37/μm2 in group C and 73.2 ± 10.4/μm2 in group D ( p < 0.01). ♦ Conclusions Prophylactic administration of oxacillin and gentamicin adequately prevented intraperitoneal infection in an animal model of chronic dialysate exposure. In addition, fibrosis was absent, suggesting intra-peritoneal infection rather than dialysate exposure is a causative factor.

The Effects of Heparin Administration in an Animal Model of Chronic Peritoneal Dialysate Exposure

Diverse modes of heparin administration have been used in animal models of chronic peritoneal dialysate exposure to maintain catheter patency and prevent fibrinous adhesions. Heparin has biological actions independent of its well-known anticoagulant activity, including the ability to modulate extracellular matrix synthesis, cellular proliferation, angiogenesis, and inflammation. These actions may interfere with peritoneal membrane homeostasis. The present study evaluated the influence of the mode of heparin administration on technique survival and infection rate in a rat model of chronic dialysate exposure. Further, the incorporation of heparin in the peritoneal membrane was examined. A 3.86% glucose dialysate was injected twice daily into Wistar rats with a heparin-coated catheter (group A1), or with a standard catheter with heparin injections during the entire exposure time (group A2) or only during 1 week (group A3). Sham manipulations were performed in a fourth group and a fifth group was left untreated. Technique survival was 80% in group A1, 60% in group A2, and 40% in group A3. The rate of infection was highest in group A1 and lowest in group A2. Intraperitoneally administered heparin accumulated in the peritoneal membrane, whereas dextran, with a molecular weight similar to that of heparin, was not incorporated in the peritoneum. In conclusion, intraperitoneal heparin reduced the incidence of infection in an animal model of chronic dialysate exposure. The best technique survival was, however, obtained using a heparin-coated catheter. Heparin is incorporated in the peritoneal membrane, where it may exert diverse biological actions and thus bias study results. The use of a heparin-coated catheter in combination with antibiotics may be the optimal approach to obtaining peritoneal access in animal models of chronic dialysate exposure.

Indwelling mesenteric venous catheterization for early detection of portal vein thrombosis: Possible application to pediatric liver transplantation

Portal vein thrombosis (PVT) is a well-recognized complication after liver transplantation, particularly in children. When it occurs early in the postoperative period, it has serious consequences, and rapid detection is essential. The purposes of this study were (1) to ascertain whether continuous monitoring of mesenteric venous pressure (MVP), via an indwelling mesenteric venous catheter, could assist in early detection of PVT and (2) to investigate the role of portography, via the catheter, in confirming this complication. An animal model of PVT was developed in pigs. At laparotomy, a heparin-coated catheter was inserted into a jejunal mesenteric vein, delivered percutaneously and connected to a pressure transducer. Conditions of PVT were simulated by progressive occlusion of the portal vein (PV) using a silastic tourniquet, and the degree of PV stenosis was assessed by Doppler ultrasound flow-velocity measurement. MVP was recorded 1 and 3 minutes after PV occlusion, and portography was performed via the indwelling catheter. There were significant increases in MVPs with all degrees of PV stenosis ( P < .01, Student's t test). No significant changes in MVP were noted between 1 and 3 minutes postocclusion. Portography clearly demonstrated PV stenosis. There were no instances of PVT, despite repeated and prolonged occlusion of the PV. Progressive degrees of PV stenosis have been clearly detected by an indwelling mesenteric venous catheter in an animal model. This method may be useful for the diagnosis and treatment of PVT after pediatric liver transplantation.

A NEW TECHNIQUE FOR EARLY DETECTION OF PORTAL VEIN AND ARTERIAL THROMBOSES

The aim of this study was to ascertain whether, in an animal model, continuous monitoring of mesenteric venous pressure (MVP) via an indwelling mesenteric venous catheter could assist in early detection of thrombosis of the portal vein (PVT) and superior mesenteric artery (SMAT). The role of portography via the catheter was also studied in confirming these complications. An animal model of PVT and SMAT was developed in pigs. At laparotomy, a 20-cm jejunal loop was isolated and a heparin-coated catheter was inserted into a mesenteric vein of the isolated jejunum and connected to a pressure transducer. Conditions of PVT were simulated by progressive occlusion of the portal vein (PV) using a silastic tourniquet and those of SMAT by superior mesenteric artery (SMA) clamping. MVPs (mm Hg) were found to significantly increase with all degrees of PV occlusion (P < 0.01, Student's t test) and to significantly decrease after SMA occlusion (P < 0.01). Portography clearly demonstrated all degrees of PV stenosis after PV occlusion and stasis of contrast medium during SMA occlusion. The authors feel that this method enables rapid diagnosis of PVT and SMAT and may be useful in the monitoring of the therapy for these complications after small bowel transplantation.

ヘパリン化抗血栓性カテーテル使用経験

ヘパリン化抗血栓性カテーテル使用経験

Heparin-coated catheters and heparin-induced thrombocytopenia

Ten patients with heparin-coated pulmonary artery catheters had heparin-induced thrombocytopenia, which persisted after all other sources of heparin were discontinued. The thrombocytopenia occurred in approximately 0.4% of the patients receiving heparin-coated catheters and remitted when the catheters were removed. The platelet counts averaged 59,000/mm3 at the time of the diagnosis and recovered to an average of 143,000/mm3 by 3 days (range 2 to 4 days) after removal of the heparin-coated catheters. One patient required a second catheter 31 days after the first catheter had been removed. When the second heparin-coated catheter was inserted, the platelet count decreased from 307,000/mm3 to 102,000/mm3 in 4 days. Segments of heparin-coated pulmonary artery catheters were placed in platelet-rich plasma and incubated with serum from patients with known heparin-associated antiplatelet antibodies or with serum from volunteers with no exposure to heparin. The heparin-coated catheters induced platelet aggregation in all samples containing serum from patients with heparin-induced thrombocytopenia. However, platelet aggregation did not occur when the catheters were incubated with the serum of the volunteers. Non-heparin-coated catheters failed to produce platelet aggregation when incubated with either sera. The high mortality and morbidity rates associated with heparin-induced thrombocytopenia mandate that afflicted patients receive no more heparin, at least until the heparin-associated antiplatelet antibodies are no longer detectable. Patients with heparin-coated catheters who have thrombocytopenia should be tested for the presence of heparin-associated antiplatelet antibodies. If heparin-induced thrombocytopenia is confirmed, the catheters must be removed if the thrombocytopenia is to be reversed and complications avoided.

Evaluation of an "in vivo" PaO2 and PaCO2 monitor in the management of respiratory failure.

A commercially available gas-chromatograph (Sentorr Gas Analyzer, Ohio Medical Products, Madison, WI) was tested, featuring continuous measurement of in vivo PaO2 and PaCO2 by means of a thin, heparin-coated catheter, inserted through an indwelling arterial line. Gas tensions are displayed every 4 min. The probes had a tendency to break rather easily, and a considerable proportion of them was faulty. We measured 105 paired determinations of blood gases obtained from patients in respiratory failure requiring mechanical ventilation with a Corning IL 175 Analyzer and displayed by the Sentorr Gas Analyzer. A high correlation (p < 0.01) existed between the two sets of values, but an estimated error of 10-20% was found in the Sentorr data. After modifications of the respirator, changes of displayed values were already notable after 4 min and 90% completed by 8-12 min. The use of this device enabled us to considerably accelerate decision-making in the management of respiratory failure. Although techology still necessitates improvements, before widespread use of in vivo monitoring of PaO2 and PaCO2 is advisable, the concept has significant clinical potential and may represent a major advance in the management of respiratory failure.