Cannula thrombophlebitis: a study in volunteers comparing polytetrafluoroethylene, polyurethane, and polyamide-ether-elastomer cannulae

Thrombosis of Angiographic Catheters in Humans: Experimental Study

One of the major problems in the use of catheters is their thrombogenicity since the embolization of clots near the central nervous system or the coronary arteries can cause permanent damage.

Catheter thrombogenicity was evaluated in humans during angiographic procedures by their tendency to become occluded. Characterization of catheters was achieved using roughness measurements, FTIR with ATR, DSC and ESCA. The catheters were 5 commercially available catheters, made mainly of polyethylene, Pebax® or polyamide sterilized and ready for clinical use. Thirty-one patients due to have an angiographic procedure and with normal blood and hemodynamic parameters were included in the study. The 50 cm catheter test sample was inserted through an introducer into the femoral artery at the beginning of an angiographic procedure. The outcoming blood flow rate (BFR) was continuously monitored by a special computerized device for 15 min or until the total amount of blood reached 30 ml. The angiographic procedure was then normally resumed.

DSC and FTIR showed results consistent with the expected composition of catheters. ESCA results showed very high Si/C ratios and could not be explained in all instances.

Occlusion of the catheters occurred in 44 % of the cases and the average time to obtain occlusion was 8.5 min (3–15 min). Values of the decrease rate of BFR in ml/min2 allowed separation of the catheters into 3 groups of low, medium and high thrombogenicity. However, occlusion occurred at least one time for each type of catheter.

Blood volume and BFR curves vs. time allowed the determination of 3 main types of thrombotic behavior: type I shows no significant reduction of BFR; type II shows a progressive decrease in flow rate; type III is much less frequent and shows an abrupt decrease of BFR either quickly followed by a compensatory increase and resuming of a steady flow or by abrupt occlusion. In type II curves the pattern of occlusion follows a classical diffusion model because the Peclet number is greater than 1 and then the classical Higbie solution for diffusion could be used (33).

The most thrombogenic material was the smoothest. There was no correlation between surface chemical composition and thrombogenicity. However, catheters that were based on PE appeared less thrombogenic than PA catheters in this study.

Low-Angled Peripheral Intravenous Catheter Tip Placement Decreases Phlebitis

Introduction

Peripheral intravenous catheters (PIVCs) are frequently removed due to phlebitis. We hypothesized that catheters made of polyurethane, which is more flexible than Teflon, would decrease phlebitis, and that flexibility could be estimated by measuring the catheter-tip angle. Ultrasonography in two groups of patients with different catheter types was then used to compare catheter-tip angles and phlebitis.

Methods

Observational studies were carried out at a medical ward in a university hospital. Infusion therapy was administered to one group of patients in 2014 using Teflon catheters (control group, n = 200), and to another group of patients in 2015 using polyurethane catheters (investigational group, n = 207). The symptoms were assessed according to a scale developed by the Infusion Nurses Society. Long-axis ultrasonography images taken immediately before catheter removal were used to measure the angle between the central line of the catheter within 2 mm from the distal point and a tangent to the vessel wall.

Results

There were no significant differences between the two groups with respect to sex, age, and medical diagnosis. In the control and investigational groups, the rates of phlebitis were 37% (73/200) and 17% (36/207), respectively (p<0.001). The median angles of the catheter tip were 7.8° and 4.1°, respectively (p<0.001). Phlebitis occurred more frequently when the catheter-tip was placed at angle >5.8°.

Discussion

The frequency of phlebitis was lower in the polyurethane, in which the catheter was placed at lower angle, almost parallel to the vessel. Our results will aid in developing new catheters and in improving PIVC-securement techniques.

The effect of cannula material on the incidence of peripheral venous thrombophlebitis

The incidence of thrombophlebitis following the use of two types of cannulae, a new generation polyurethane cannula Biovalve PUR and a polyurethane hybrid co-polymer Vialon cannula, was compared in a randomised trial. Seventy patients scheduled for elective cardiac surgery were randomly assigned to have either a Biovalve cannula or a Vialon cannula inserted before induction of anaesthesia. Postoperatively, the cannulae were removed either as soon as signs of thrombophlebitis were observed or at the end of seven days, whichever was earlier. There was a significantly lower incidence of thrombophlebitis in the Biovalve PUR group (17%) compared to the Vialon group (60%) at the end of seven days (p < 0.001). None of the cannulae tip cultures resulted in the growth of micro-organisms. There was also a lower incidence of the need for re-siting with the Biovalve than with the Vialon cannulae.

Different kinetics of the respiratory burst response in granulocytes, induced by serum from blood coagulated in contact with polymer materials

Tubes of different polymer materials were filled with blood collected by venous puncture. The blood was allowed to clot for 10 min, and the serum was collected. Complement activation was demonstrated through assessment of the C3-level by radial immunodiffusion. Phospholipid fingerprints were made after lipid extraction of serum and separation by thin-layer chromatography. The granulocyte fraction of venous blood was separated on a Percoll gradient and the cells were either loaded with a calcium probe, or incubated with luminol. These cells were used as a biological test for inflammatory mediators. Serum from blood coagulated in contact with different materials was added to the test cells. The intracellular calcium level was recorded by Calcium Green-1 fluorescence and the respiratory burst of the test cells was recorded by luminol-amplified chemiluminescence. Serum from blood coagulated in contact with glass tubes, methylised glass tubes and teflon (PTFE) tubes induced a transient increase of the cellular calcium level, indicating a G protein-coupled activation of the test cells. Serum from blood coagulated in contact with glass tubes, methylised glass tubes, and PTFE tubes primed the test cells for a subsequent f-MLP response. Serum from blood coagulated in contact with polyurethane and polypropylene induced a direct biphasic respiratory burst response in the test cells and serum from blood coagulated in contact with methylised glass induced a direct monophasic respiratory burst response in the test cells. Complement activation was demonstrated after blood contact with hydrophobic glass and PTFE. Different fingerprints of phospholipid content were found in sera after blood contact with different materials. The data show that different inflammatory mediators are released during blood coagulation in contact with different materials. The method may be valuable as a screening test for blood compatibility of materials.

Effect of education on evidence-based care and handling of peripheral intravenous lines

Deficient routines in use, care, handling and documentation of peripheral intravenous vein cannulae (PIV) have previously been reported, and complications have been noted in 50-75% of the patients. The aim of the study was to examine whether specially trained nurses change their actions to decrease complications when using cannulae. The study included 36 nurses assigned to experimental and control groups. The experimental group followed an education programme explaining how to use and take care of a PIV. To evaluate the intervention document analysis, observations and patient interviews were performed in 99 patients with 172 PIVs in situ for less than 24 h. After the education programme, fewer complications, more carefully performed care and handling, and better documentation and information were found in the experimental group. Nurses in the control group followed current routines, which resulted in a greater degree of complications. Education in evidence-based care and handling gives nurses the opportunity to improve their ability to use theoretical knowledge in clinical problems.

Infusion phlebitis in patients with acute pneumonia: a prospective study

STUDY OBJECTIVES

To prospectively assess the relative risk for phlebitis in a series of consecutive patients with pneumonia and to identify risk factors that predict an increased risk for phlebitis.

SETTING

Internal medicine department of a tertiary teaching hospital.

PATIENTS

Seven hundred sixty-six consecutive patients with acute pneumonia receiving IV therapy.

INTERVENTIONS

Only the first catheter was taken into account. There were 308 short lines (a 51-mm, 18-gauge Teflon catheter); 307 midsized lines (a 28-cm, 16-gauge polyvinyl chloride catheter); and 151 long lines (71-cm, 14-gauge plain polyurethane catheter). Eighteen variables were prospectively evaluated in an open, nonrandomized study for their contribution to the occurrence of phlebitis.

RESULTS

The overall phlebitis rate was 39%. Phlebitis developed in 53% of patients with short lines, in 41% of patients with midsized lines, and in 10% of patients with long lines, and these catheters remained in place an average (+/- SD) of 3.0+/-2.4 days, 4.6+/-3.4 days, and 7.8+/-6.6 days, respectively. The variables that influenced the development of phlebitis, as determined by multivariate analysis, were the following: type of catheter; blood hemoglobin levels; and IV therapy with either corticosteroids or erythromycin.

CONCLUSIONS

According to our data, when the use of a catheter is expected to be required for < or = 36 h, a short line can be used. If a longer duration is expected, a longer line is warranted. Ours is the first study in which the relationship between blood hemoglobin levels and phlebitis has been reported. Because the use of intravascular devices is increasingly common, a more complete knowledge of the factors that influence their acceptance has become essential.

Hemodialysis access failure: a call to action

Recent evidence suggests that the cost as well as the morbidity associated with the maintenance of hemodialysis access is increasing rapidly; currently, the cost exceeds 1 billion dollars and access related hospitalization accounts for 25% of all hospital admissions in the U.S.A. This increase in cost and morbidity has been associated with several epidemiological trends that may contribute to access failure. These include late patient referral to nephrologists and surgeons, late planning of vascular access as well as a shift from A-V fistulaes to PTFE grafts and temporary catheters, which have a higher failure rate. The reasons for this shift in the types of access is multifactorial and is not explained by changes in the co-morbidities of patients presenting to dialysis. Surgical preference and training also appear to play an important role in the large regional variation and patency rate of these PTFE grafts. We propose a program for early placement of A-V fistulae, a continuous quality improvement, multidisciplinary program to monitor access outcome, the development of new biomaterials, and a research plan to investigate pharmacological intervention to reduce development of stenosis and clinical interventions to treat those that do develop, prior to thrombosis.

Reduced intravascular catheter-related infection by routine use of antibiotic-bonded catheters in a surgical intensive care unit

We report a comparative analysis of intravascular catheter-related infection before and after routine use of antibiotic-bonded catheters in an intensive care unit. Cefazolin-bonded catheters were placed in patients requiring catheterization for at least 3 days, or with remote infection, standard catheters at other times. One thousand forty-five catheters (259 patients) over 6 months were compared with 801 (236 antibiotic-bonded, 565 standard) catheters (239 patients) the next 6 months. After use of antibiotic-bonded catheters, we found: 1.7% catheters infected versus 3.7% (p = 0.01); catheter-associated bacteremia 0.1% versus 1.3% (p < 0.005); catheter-related infection rate 4.39 versus 10.73 per 1000 patient days (p < 0.005), and 5.06 versus 11.47 per 1000 catheter days (p < 0.01); and cumulative risk of infection decreased (p < 0.005). Antibiotic-bonded catheters were used with more remote infections (52% versus 27%, p < 0.001), had longer indwelling time (4.4 versus 3.1 days, p = 0.0001), and more were inserted over a guide wire (66% vs. 28%, p < 0.001). In conclusion routine use of antibiotic-bonded catheters was associated with a significant reduction in infectious complications.

A prospective clinical comparison of two intravenous polyurethane cannulae

Tissue irritation, as evidenced by phlebitis, associated with Optiva (Johnson & Johnson Medical) and Insyte (Becton Dickinson) polyurethane cannulae was studied. The integrity of the cannulae on removal, the incidence of infection at the cannula site and the factors which influence phlebitis were also examined. One thousand and eight patients had a polyurethane cannula placed for induction of anaesthesia for cardiac surgery. After surgery, the cannula was examined every 24 hours. If evidence of phlebitis occurred, the cannula was removed and sent for culture. All remaining cannulae were removed at 72 hours and the site examined daily for a further three days. There were 503 Optiva and 505 Insyte cannulae studied. The distributions between the two cannulae with respect to patient characteristics, gauge of cannula, number of attempts and difficulty of insertion, cannula site and anaesthetist inserting were similar. The early removal rate for both groups was 47%. Overall phlebitis rate with Optiva was 31% and Insyte 33%. This difference is not statistically significant. The cumulative phlebitis rate increased with time but did not differ between the two types of cannulae. Minor tip distortion or shaft kinking of the cannulae occurred in 16.2% of Optiva and 23.5% of Insyte. This difference is statistically significant and may relate to the slightly more acute taper at the Optiva cannula tip. Both cannulae were similar in clinical performance.

A prospective clinical comparison of two intravenous polyurethane cannulae

Tissue irritation, as evidenced by phlebitis, associated with Optiva (Johnson & Johnson Medical) and Insyte (Becton Dickinson) polyurethane cannulae was studied. The integrity of the cannulae on removal, the incidence of infection at the cannula site and the factors which influence phlebitis were also examined. One thousand and eight patients had a polyurethane cannula placed for induction of anaesthesia for cardiac surgery. After surgery, the cannula was examined every 24 hours. If evidence of phlebitis occurred, the cannula was removed and sent for culture. All remaining cannulae were removed at 72 hours and the site examined daily for a further three days. There were 503 Optiva and 505 Insyte cannulae studied. The distributions between the two cannulae with respect to patient characteristics, gauge of cannula, number of attempts and difficulty of insertion, cannula site and anaesthetist inserting were similar. The early removal rate for both groups was 47%. Overall phlebitis rate with Optiva was 31% and Insyte 33%. This difference is not statistically significant. The cumulative phlebitis rate increased with time but did not differ between the two types of cannulae. Minor tip distortion or shaft kinking of the cannulae occurred in 16.2% of Optiva and 23.5% of Insyte. This difference is statistically significant and may relate to the slightly more acute taper at the Optiva cannula tip. Both cannulae were similar in clinical performance.

Complement activation by angiographic catheters in vitro

PURPOSE

Four different polymers used in commercial angiographic catheters were compared in vitro with respect to their ability to activate the complement system.

MATERIALS AND METHODS

Commercially available angiographic catheters made from one of the following plastics were used: polyamide, polyethylene, polyurethane, and polytetrafluoroethylene. Silicone-coated latex urinary catheters served as the reference standard. Each catheter was cut into 20-mm segments, immersed in a polypropylene tube containing fresh serum from a volunteer donor, and incubated at 37 degrees C. Samples were drawn at 15 minutes, 1 hour, and 6 hours; C3 activation products (C3AP) and the terminal complement complex (TCC) content were estimated with enzyme immunoassays.

RESULTS

By 1 hour, a significant increase in C3AP and TCC concentrations was observed with all angiographic catheters relative to controls (P < .01-.001). The time-concentration plots for both C3AP and TCC were steepest for polyamide. C3AP concentrations relative to controls were significantly higher with exposure to polyamide compared with polyurethane at 1 hour (P < .01), and with both polyethylene and polyurethane at 6 hours (P < .01). Polytetrafluoroethylene induced larger amounts of C3AP formation by 6 hours than polyethylene and polyurethane (P < .05). However, polytetrafluoroethylene was associated with the lowest relative median concentrations of TCC; the difference with polyamide was significant at 6 hours (P < .001). As with C3AP, differences in TCC generation between polyethylene and polyurethane were marginal at all observation points (P > .05).

CONCLUSIONS

All the polymers tested activated the complement system. Activation was most prominent with exposure to polyamide and least marked with polyurethane.

Subcutaneous, catheter-related inflammation in a rabbit model correlates with peripheral vein phlebitis in human volunteers

In the development of a polyurethane vascular catheter with anti-infective properties, it became desirable to develop a measure of tissue inflammation. This was investigated in a rabbit model by implanting uncoated catheters and catheters coated with heparin (HEP), chlorhexidine (CH), or CH/HEP in the subcutaneous space with or without 10(4) Staphylococcus aureus. At intervals of 2, 4, and 7 days after implantation, animals were sacrificed; tissue blocks containing catheters were removed and preserved with formaldehyde; and sections were stained with hematoxylin and eosin. Using a histologic index, 240 sections (10 for each experimental condition) were evaluated by two investigators blinded to experimental conditions. Uncoated catheters or catheters coated with CH alone had a lower histologic index (less inflammation) than catheters coated with HEP alone or CH/HEP (P < .05). When catheters were inoculated with S. aureus, those coated with CH, with or without HEP, had a lower histologic index than uncoated catheters (P < .05). Next, 30 volunteers had a control catheter inserted in a vein in one forearm and a catheter coated with either CH alone or CH/HEP in a vein in the other forearm. After 96 h of observation there was a greater risk of phlebitis associated with CH/HEP catheters than control catheters (P < .05), and no difference in the risk of phlebitis between CH catheters and control catheters (P = 0.43). Thus, the amount of inflammation around the catheter in the subcutaneous space of rabbit correlated with the risk of peripheral vein phlebitis.

Surface modification of intravenous catheters to reduce local tissue reactions

Surface modification of polymer materials used in intravascular catheters reduces the in vitro adhesion of plasma proteins involved in blood coagulation. Intravenous Teflon cannulae, native and surface-modified with ethyl hydroxyethyl cellulose, were compared using clinical examination and laser Doppler flowmeter (LDF) measurements of local cutaneous blood flow. Nine volunteers were simultaneously subjected to both types of cannulae for a period with a maximum of 4 d. Native Teflon catheters showed a larger incidence of catheter-associated tissue reactions, first demonstrated by early increases in laser Doppler recordings of skin blood flow. These results indicate that surface modification of polymer intravascular catheters attenuates tissue response against the foreign material and that altered LDF measurement precedes the clinical recognition of thrombophlebitis.

Single versus double occlusive dressing technique to minimize infusion thrombophlebitis: Vialon and Teflon cannulae reassessed

Infusion thrombophlebitis is the commonest complication of intravenous cannulation. This study was undertaken to prospectively evaluate a double-occlusive dressing technique and a new cannula, bismuth oxide-Teflon (Critikon Inc., Aust.), comparing it to Vialon (Deseret Medical Inc., Utah, USA). The study group of two hundred patients had a 16 gauge intravenous cannula inserted in theatre using a standard technique. The incidence of thrombophlebitis was determined on a daily basis. Cannula tips were sent for culture on removal. Vialon was found to be superior to Teflon after day 1. Although a double-occlusive dressing technique increased the duration of cannulation (50.9 vs. 41.9 hours, P less than 0.05), there was no difference in the incidence of thrombophlebitis. Neither cannula material nor dressing technique had an influence on the results of cannula tip culture (6% incidence). There was no evidence of bacteraemia in any case.

Penetration forces in cannulation of the dorsal veins of the hand: I. A comparison between polyurethane (Insyte) and polytetrafluoroethylene (Venflon) cannulae. Results of a study in volunteers compared with those from an in vitro study

The functional tip tapering design of peripheral venous cannulae (introducer steel needle + catheter) made of polyurethane (PUR-Instye) and polytetrafluoroethylene (PTFE-Venflon) was studied with 3 techniques: A) Scanning electron microscopy (SEM). B) Measurement of penetration forces in vitro through latex membranes and lamb skins with a tensile-compression apparatus (Instron-1122) at 1) the introducer steel-needle point, 2) the needle heel (the spot marking the passage from the point of the needle to its shaft). 3) the catheter top (i.e. the beginning of the plastic sheath), 4) the catheter tip, i.e. the beginning of the largest diameter of the plastic sheath, and 5) between the catheter tip and its hub (catheter friction). C) Two cannulae (one of each type for every subject were inserted at random into the dorsal veins of the left and right hand in 37 volunteers, and the penetration forces were measured with a force transducer.

RESULTS

A) The PUR-cannulae had a lancet-like appearance and a smoother transition at the catheter top, whilst the PTFE cannulae were arrow-like, cut back and had a less accentuated conical design. B) Penetration forces in vitro through latex membranes were 9-41 times lower (P less than 0.0001) than those through the large skins. The highest forces (mean +/- s.d.) registered in vitro (lamb skins) were 4.1 +/- 0.2 Newtons (N) with PUR-cannulae at the catheter tip, and 3.4 +/- 0.6 with the PTFE-cannulae at the catheter top (P less than 0.05). C).(ABSTRACT TRUNCATED AT 250 WORDS)