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PubMed2006

Handling of peripheral intravenous cannulae: effects of evidence-based clinical guidelines.

AIM: This study aimed at evaluating the outcome of implemented evidence-based clinical guidelines by means of surveying the frequency of thrombophlebitis, nurses' care, handling and documentation of peripheral intravenous cannulae. BACKGROUND: Peripheral intravenous cannulae are frequently used for vascular access and, thereby, the patients will be exposed to local and systemic infectious complications. Evidence-based knowledge of how to prevent these complications and how to care for patients with peripheral intravenous cannula is therefore of great importance. Deficient care, handling and documentation of peripheral intravenous cannulae have previously been reported. DESIGN: A cross-sectional survey was conducted by a group of nurses at three wards at a university hospital before and after the implementation of the evidence-based guidelines. METHOD: A structured observation protocol was used to review the frequency of thrombophlebitis, the nurses' care, handling and the documentation of peripheral intravenous cannulae in the patient's record. RESULTS: A total of 107 and 99 cannulae respectively were observed before and after the implementation of the guidelines. The frequency of peripheral intravenous cannulae without signs of thrombophlebitis increased by 21% (P < 0.01) and the use of cannula size 0.8 mm increased by 22% (P < 0.001). Nurses' documentation of peripheral intravenous cannula improved significantly (P < 0.001). CONCLUSION: We conclude that implementation of the guidelines resulted in significant improvements by means of decreased frequency of signs of thrombophlebitis, increased application of smaller cannula size (0.8 mm), as well as of the nurses' documentation in the patient's record. RELEVANCE TO CLINICAL PRACTICE: Further efforts to ameliorate care and handling of peripheral intravenous cannulae are needed. This can be done by means of increasing nurses' knowledge and recurrent quality reviews. Well-informed patients can also be more involved in the care than is common today.

Cross-Sectional Studies↗
PubMed1995

Cannula selection and cannulation techniques for nonpulsatile mechanical ventricular assistance.

The successful use of mechanical ventricular assistance is, in large part, dependent upon easy insertion of well designed inflow and outflow cannulas. This manuscript describes a family of cannulas specifically designed for use in a nonpulsatile ventricular assist device (VAD) circuit. Although a variety of commercially available cannulas can be employed in a nonpulsatile VAD circuit, the cannulas described in this manuscript possess a number of unique design features. The reinforced thin-walled design and end hole construction optimize fluid flow characteristics in both the inflow and outflow cannula. The extended length allows the cannulas to transverse the skin at a point far distant from the mediastinum, reducing the potential for ascending cannula site infection. The purpose of this manuscript is not to review all cannulas available for nonpulsatile VAD circuits, but rather to describe in detail a family of cannulas that are ideal VAD cannulas based on their design characteristics. In addition individual cardiac surgeons implant very few of these devices annually. Thus the advantages and disadvantages of common cannulation sites and a proven technique for cannula insertion will also be presented.

Aorta↗
PubMed1995

Flow characteristics of aortic cannulae.

Atheroembolism from the ascending aorta is an emerging cause of noncardiac complications after open heart surgery. We designed a new arterial cannula specifically to reduce the exit force and velocity of blood flow, thereby reducing the "sandblasting" effect of the exiting blood jet. The cannula has a closed tip and an internal cone that diffuses blood flow such that it enters the aorta via multiple side holes. Fluid dynamics of the cannula were tested against five frequently used cannulae: Sarns High-Flow (3M Sarns High-Flow, Ann Arbor, MI, USA), DLP 83024 (DLP Inc., Grand Rapids, MI, USA), RMI ARS 024C (Research Medical Inc. of Research Industries Corp., Midvale, UT, USA), Bard 1966 (C.R. Bard Inc., Haverhill, MA, USA), and Argyle THI (Sherwood Medical Co. Sub American Home Products Corp., St. Louis, MO, USA). All cannulae had an 8.0-mm external diameter. The new cannula demonstrated a similar pressure drop and internal tip diameter as the others. The exit force (newtons) of the Soft Flow cannula was significantly less than the Sarns High-Flow (p < 0.05), DLP (p < 0.001), RMI (p < 0.01), Bard (p < 0.001), and the Argyle (p < 0.001) cannulae. Peak velocity (cm/s) of the Soft Flow cannula was significantly less than the DLP (p < 0.01), RMI (p < 0.01), Bard (p < 0.01), and Argyle (p < 0.001). The cannulae all had similar hemolysis rates. The new arterial cannula produced the lowest exit force and flow velocity with no increase in hemolysis and may help to decrease the incidence of atheroemboli and its sequelae.

Cardiac Surgical Procedures↗
PubMed2002

Prone positioning does not affect cannula function during extracorporeal membrane oxygenation or continuous renal replacement therapy.

INTRODUCTION: Prone positioning in respiratory failure has been shown to be a useful adjunct in the treatment of severe hypoxia. However, the prone position can result in dislodgment or malfunction of tubes and cannulae. Certain patients receiving extracorporeal membrane oxygenation (ECMO) or continuous renal replacement therapy (CRRT) may also benefit from positional therapy. The impact of cannula-related complications in these patients is potentially disastrous. The safety and efficacy of prone positioning of these patients has not been previously reported. MATERIALS AND METHODS: A retrospective chart review evaluated ECMO or CRRT cannula location, and displacement or malfunction during positional change or while prone. The study was set in a General Surgery and Trauma Intensive Care Unit. The subjects were all patients at our institution who simultaneously underwent ECMO or CRRT and prone positioning from July 1996 to July 2001. There were no interventions. RESULTS: Ten patients underwent ECMO and 42 patients underwent CRRT during the study period. Seven patients underwent simultaneous prone positioning and either ECMO (4/10) or CRRT (4/42). A total of 68 turning events (prone to supine or supine to prone) were recorded, with each patient averaging 9.7 (range, 4-16) turning episodes. Turning was performed with sheets and extra nursing personnel; no special mechanical assist devices were used. No patients experienced inadvertent cannula removal during turning. Two patients had poor flow through their cannulae. In one patient, this occurred in the supine position and required repositioning of the cannula. In the second patient, cannulae were changed twice and flow was poor in both the supine and the prone positions. All ECMO and CRRT patients received venous cannulae. Cannula location (seven internal jugular and 11 femoral) did not the affect risk of malfunction. DISCUSSION AND CONCLUSIONS: Patients with venous cannulae for ECMO or CRRT can be safely placed in the prone position. Flow rates are maintained in this position. Potential cannula complications of ECMO and CRRT are not a contraindication to prone positioning in severely ill patients.

Adult↗
PubMed1993

Diagnosing proximal tubal obstruction: evaluation of peak intrauterine pressures using four common cannula techniques in extirpated uteri.

OBJECTIVE: To compare the ability of four chromotubation techniques to generate and maintain intrauterine pressures in the diagnosis of proximal tubal obstruction. METHODS: Sixteen extirpated uteri were used for this study. A pressure catheter was placed through the fundus into the endometrial cavity. Three cannulas were evaluated: 1) the Cohen cannula with hold and no-hold techniques, 2) the BARD cervical cannula (dual intrauterine and intracervical balloons), and 3) the Harris-Kronner uterine manipulator-injector catheter with an intrauterine balloon. Intrauterine pressures were monitored while warm saline was infused. The studies were performed with the tubes obstructed, and measurements of peak attainable intrauterine pressures were recorded. Data were analyzed by t test, with significance set at P < .05. RESULTS: Peak intrauterine pressures for the four groups were as follows: 1) Cohen cannula, not holding, 40.7 +/- 5.1 mmHg; 2) Cohen cannula, holding in place, 63.6 +/- 5.3 mmHg; 3) BARD cannula, 112.4 +/- 3.5 mmHg; and 4) Harris-Kronner cannula, 106.3 +/- 4.3 mmHg. The BARD and Harris-Kronner cannulas achieved significantly higher intrauterine pressures than either method of using the Cohen cannula (P < .001). There was no statistically significant difference between the BARD and Harris-Kronner cannulas. CONCLUSION: Significant differences in achievable intrauterine pressures were demonstrated among catheters in our in vitro model. Based on these findings, we believe that the BARD, Harris-Kronner, or other intrauterine balloon-type cannula should be used before diagnosing proximal tubal obstruction.

Catheterization↗
PubMed1994

Maximizing the stability of oxygen delivered via nasal cannula.

BACKGROUND: The effective fractional inspired oxygen concentration (FiO2) of supplemental oxygen provided to infants via nasal cannula may be adjusted by changing cannula flow rate or oxygen concentration, factors within our control. However, FiO2 also varies with changes in the patient's breathing, factors beyond our control. While a stable oxygen delivery is desirable, combinations of flow and concentration that maximize stability over time need to be studied. OBJECTIVE: To assess the impact of different weaning strategies on the stability of inspired oxygen concentrations delivered to infants via nasal cannulas and to identify optimum strategies maximizing that stability. DESIGN: Theoretical analysis and comparison with previously published measurements. METHODS: We derived equations predicting the FiO2 delivered to infants via nasal cannula, incorporating traditional adjustments of cannula flow rate and oxygen concentration, as well as considering the impact of the infant's inspiratory time, tidal volume, and fraction of nasal breathing. We compared predicted results with previously published measures and evaluated strategies to maximize oxygen delivery stability over time. RESULTS: Predicted values correlated well with published hypopharyngeal measurements (r = .97) and were unbiased, accurate predictors of FiO2. Effective FiO2 was least likely to be affected by changes in patient-controlled controlled factors when the nasal cannula flow rate was as low as possible. CONCLUSIONS: To minimize variability in oxygen delivery via nasal cannula to infants, cannula flow should be reduced to the lowest possible flow by using undiluted (100%) oxygen. Supplemental oxygen may then be weaned by making small reductions in cannula flow. Cannula oxygen concentration should be reduced below 100% only after the minimum calibrated flow rate is reached. Such a strategy may maximize the stability of delivered oxygen over time as well as minimize the size of changes in delivered oxygen at each step of the weaning process.

Catheterization↗
PubMed1990

Mupirocin for the reduction of colonization of internal jugular cannulae--a randomized controlled trial.

In a prospective study, 218 cardiothoracic patients, in whom 'Abbocath-T' cannulae had been inserted preoperatively into the internal jugular vein, were randomized to receive skin preparation of the insertion site with tincture of iodine (108 controls) or tincture of iodine followed by application of sterile 2% calcium mupirocin ointment (110 test patients). Cannulae were usually removed within 48 h of the operation. Patients receiving mupirocin were less likely to develop significant colonization of one or more of their cannulae as judged by Maki's criterion of a yield of greater than 15 colony forming units (cfu) from a cannula segment rolled on an agar plate (17% of mupirocin treated patients compared with 54% of the controls, P less than 0.001). Coagulase-negative staphylococci, micrococci, or both, were the commonest isolates and were cultured from 70% of the 186 control cannulae compared with 24% of 172 cannulae inserted through mupirocin-treated skin (P less than 0.001). A count of more than 15 cfu was found on the tips of 25% control cannulae compared with 5% of the cannulae from mupirocin-treated patients, an effect which was independent of in-situ time (P less than 0.001). For cannulae with colonized tips, the same species was isolated from the skin of the insertion site in 67%, from the exterior of the hub in 61% and from the lumen in only 15%. There were no side effects attributed to mupirocin or superinfection with resistant organisms. We conclude that in cardiothoracic patients the application of mupirocin after standard skin preparation with tincture of iodine significantly reduces the colonization of central venous cannulae by organisms derived from the skin insertion site.

Adolescent↗
PubMed2005

A bent infusion cannula for vitreous surgery.

PURPOSE: To modify an infusion cannula for vitreous surgery and decrease cannula-related complications. DESIGN: New surgical instrument. METHODS: A conventional 20-gauge infusion cannula was modified by forming a 135-degree angle at the joint of the flange between the cannula adapter and the needle. The sloped plane of the needle tip was opposite the bent adapter. The cannula was routinely fastened with a 7-0 absorbable suture after insertion into the eye. RESULTS: We used the modified infusion cannula in 50 consecutive phakic eyes (48 patients). Intraoperatively, the cannula remained attached to the globe surface; it did not tilt anteriorly and damage the lens when touched inadvertently. No suprachoroidal or subretinal infusion was observed. Neither the lens nor the retina was damaged. There were no cannula-related retinal detachments or breaks during follow-up. CONCLUSIONS: The modified infusion cannula is more effective and safer during pars plana vitrectomy in phakic eyes compared with a conventional cannula.

Catheterization↗
PubMed1985

A comparison of flow gradients across disposable arterial perfusion cannulas.

Five-hundred members of The Society of Thoracic Surgeons were canvassed to discover which cannulas are currently used for open-heart surgical procedures in adults; 120 surgeons responded. The mean arterial line pressure produced by 29 disposable arterial perfusion cannulas (size range, 16F to 30F) at flow rates of 1 to 5 liters per minute was compared. A roller pump with perfusion tubing 95 mm (0.75 inch) in diameter was used with water as the test solution. Line pressures in these cannulas ranged from 22.4 +/- 2.30 (standard deviation) to 271.0 +/- 6.60 mm Hg at 5 L/min. Four 24F cannulas had gradients of less than 55 mm Hg at a flow rate of 5 L/min, and 6 cannulas--4 of which were 22F and 2, 24F--had gradients higher than 150 mm Hg at 5 L/min. A number of cannulas kinked easily, and these showed marked increases in line pressure. The following results were obtained from this study: (1) a wide range of line pressures was observed in disposable arterial perfusion cannulas currently in clinical use; (2) some cannulas currently used for cardiopulmonary bypass in adults generated excessive line pressure; and (3) both material and design affect function, with some designs being safer than others. Cardiac surgeons should base the choice of an arterial perfusion cannula on the best performance and safest design available to avoid cannula-related problems at operation.

Aorta↗
PubMed1997

Technical and economic feasibility of reusing disposable perfusion cannulas.

OBJECTIVE(S): The reuse of disposable devices is a potential source of significant cost savings to hospitals. Venous and arterial perfusion cannulas under new and reused conditions were selected to identify the clinical, safety, technical, logistic, and economic issues that must be addressed to realize these savings. METHODS: Single- and dual-stage venous and arterial cannulas from two manufacturers were tested when new, after initial clinical use, and after a single clinical use plus up to nine simulated reuses. Reuse was simulated by end-to-end bending, coupling and uncoupling of the connectors, and by two 1-hour soaks in plasma at 4 degrees and 40 degrees C, respectively. Cannulas were decontaminated and then processed by a peracetic acid-based liquid chemical sterilization system after each use/reuse. Sterilization was validated by eliminating Bacillus subtilis spores from the cannulas on each of five consecutive cycles. Cannulas were tested for physical changes, functional integrity, biocompatibility, and in vivo performance in sheep. A cost analysis was also performed. RESULTS: Sterilization was successfully achieved. Mechanical changes were less than 20% on all variables studied and were undetectable by experienced cardiac surgeons in selective evaluation. No clinically important differences were found between new and reused cannulas, even after nine simulated reuses. Reusing cannulas four times would reduce the cost per procedure from $53 to $19 (64%). CONCLUSIONS: Preliminary data suggest that the perfusion cannulas tested can be safely and efficaciously used five times. Limited reuse of these disposable cannulas is technically feasible and cost-effective. Cannula reuse would result in a small incremental savings; however, with more expensive devices and higher-volume sterilization procedures, the savings could be considerably greater. This program provides a model for evaluation of other single-use medical devices for reuse.

Animals↗
PubMedDate not supplied

Complications associated with cannula insertion techniques used for laparoscopy in standing horses.

OBJECTIVE: To report our experience and complications associated with different cannula insertion techniques for laparoscopy in standing horses. STUDY DESIGN: Retrospective study. SAMPLE POPULATION: Forty horses that had laparoscopy for diagnostic or surgical purposes. METHODS: After a physical examination, including rectal palpation, standing laparoscopy was performed in 40 sedated horses. Local anesthetic was injected at each site of cannula insertion in the left flank. Horses were divided into 5 groups: Pneumoperitoneum was induced before cannula insertion using a Verres needle (group 1, n = 3) or a 12-g catheter (group 2, n = 14); the cannula was inserted before inducing a pneumoperitoneum (group 3, n = 9); the cannula was inserted under visual control, using an operating laparoscope (group 4, n = 2) or a Visiport Optical Trocar (group 5, n = 12). Horses were observed for 7 days. RESULTS: Problems with insufflation or cannula insertion occurred in 12 horses: 6 had peritoneal detachment, 4 had a splenic puncture, and 2 had descending colon puncture. Eleven of these complications occurred in groups 1 to 3 and only 1 in groups 4 and 5. CONCLUSIONS: The Visiport optical device allows controlled insertion of the initial trocar, and thus avoided potential problems associated with "blind" cannula insertion techniques and was used effectively in horses that had feed withheld for 12 hours. This technique enables direct insertion of a cannula directly into the right flank. CLINICAL RELEVANCE: Complications associated with initial cannula insertion in the paralumbar fossa, for laparoscopy, in standing horses can be minimized with the use of an optical cannula.

Anesthetics, Local↗
PubMed1997

Assessing blunt cannulae as replacements for hypodermic needles during intravenous therapy: safety and utility.

OBJECTIVE: Recently, blunt 18-gauge (ga) metal cannulae have become nationally commercially available as safety products. The ability of these blunt cannulae to prevent needlestick injury and to enable direct access of all standard latex ports and vial membranes, thus eliminating hypodermic needles entirely from the intravenous (i.v.) drug administration process, is assessed. DESIGN AND SETTING: In the laboratory setting, the needlestick injury potential of small-bore blunt cannulae versus hypodermic needles was studied using blinded and randomized methods. Insertion force requirements were studied for cannulae and needles. Metal 18-ga blunt cannulae were inserted into four brands of standard Y-ports and vial stoppers to assess postpuncture integrity and force requirements. RESULTS: Needlestick injury did not occur using small-bore blunt cannulae (P < .001; n = 51). Metal 18-ga cannulae passed into prepierced standard Y-ports as easily as hypodermic needles and without loss of Y-port integrity. Insertion of metal 18-ga cannulae without prior port puncture was possible, but was associated with substantial coring and loss of integrity of the port seal, except for IVAC brand ports (P < .03). CONCLUSIONS: Metal 18-ga cannulae can be inserted through virtually all intact standard rubber vial membranes or standard Y-ports to allow safe IV access. A single prepuncture of any standard latex membrane allows economical blunt metal cannula access equally efficiently as with expensive pre-slit membranes and without loss of membrane integrity.

Equipment Design↗
PubMedDate not supplied

An original inflow cannula for paracorporeal assist devices.

Cannulae for paracorporeal ventricular assist devices have been clinically shown to be limiting factors in optimal circulatory support. A new inflow cannula has been manufactured according to an original silicone rubber molding process, permitting a hemocompatible inner surface. The cannula is 200 mm in length, with a 10 mm internal diameter. The wall is 3 mm thick and reinforced by a stainless steel spiral spring embedded in the silicone. An external ring permits adequate interface between the cannula and the endocardial surface of the atrium. A compliant external segment on the inflow cannula, free of any spiral spring, allows adjustment of vacuum to optimal values, thus avoiding inflow obstruction. The cannula has been tested during 1 to 5 days of left ventricular bypass in calves (n = 15). A Symbion AVAD, Utah 85 VAD, or Centrimed pumps were used. Adequate heparinization was maintained throughout. Paracorporeal flow was 0.045 L min-1 kg-1. In vivo evaluation was made by hemodynamic studies and the incidence of thromboembolism. The cardiac cavities, cannulae, and peripheral vessels were carefully searched for thrombi and emboli at autopsy. The atrium, the interface between atrium and silicone cannula, and the cannula itself were found free of any deposit. This aspect differed from that observed previously with available PU or PVC cannulae.

Animals↗
PubMedDate not supplied

Silicone tracheal cannula.

This presentation is to introduce a silicone tracheal cannula which has been designed for use in selected cases instead of a tracheotomy tube. The design of the cannula was developed in the laboratory and has now been used clinically over a period of four years in 26 cases. Special features of the cannula include a one-size diameter which is suitable for all adults. An inner flange is shaped so as to conform with the inner aspect of the anterior wall of the trachea and to prevent rotation and anterior displacement of the cannula. The inner flange is angulated to allow for proper direction of the long axis of the cannula. An outer flange fits into one of a number of grooves and prevents posterior displacement of the cannula. Thus far the silicone tracheal cannula has been used in cases of sleep apnea, bilateral vocal cord paralysis in the position of adduction, intermittent glottic insufficiency, laryngeal carcinoma, chronic lung disease, and short-term necessity for a tracheotomy. Special equipment has been designed for ease of the surgical procedure required for insertion of the cannula. A one-way valve has been designed which is easily applied to the cannula. A variation of the silicone tracheal cannula has been designed for long-term use.

Catheterization↗
PubMed2000

Efficacy of securing cannulae with different taping methods.

This study compared locally available adhesive tapes and dressings in a block randomized, blinded study to determine the force required to dislodge a cannula. In the first stage of the study, various tapes and taping methods were used to secure a cannula to a polyvinylchloride (PVC) pipe. The cannula was attached to a section of a giving set which in turn was attached to a dynamic force transducer. The force required to dislodge the cannula, together with the methods of dislodgement were recorded. In stage two the best taping technique for each type of tape was tested by attaching a cannula to the surface of the forearm of an adult male volunteer. Of the tapes tested we found Leukoplast to be the most effective tape for securing the cannula to the PVC model. On the adult forearm Sleek was as effective as Leukoplast. Orientating the tape parallel to the long axis of the cannula and taping the cannula hub-giving set connection both improved the adherence of the cannula. Under the conditions tested, sterile adhesive dressings and tapes were relatively ineffective in securing the cannulae.

Adult↗
PubMedDate not supplied

[Effect of two different tracheal cannula change schedules on microbiological contamination and patient comfort].

Tracheostomy is a commonly used technique in intensive care units, but there are no uniform criteria governing the periodicity with which tracheal cannulas should be changed. The objective of our study was to evaluate if different cannula-change schedules modified microbiological contamination and reduced the pain and bleeding related with cannula changes. In a comparative study of two groups, a control group in which the cannula was change every 48 hours and an experimental group in which the cannula was changed every 5 days were studied. Demographic differences, tracheostomy technique, microbiological study of the cannula, bronchial aspirate and stoma, clinical signs of stomal infection and secretions, and chest radiography were compared in the two groups. With each cannula change, we evaluated bleeding, pain, type of ventilation, hemodynamic disturbances, airway obstruction, opening of a false airway, oxygen saturation before and after cannula change, and recovery time. The study included 29 patients and 97 cannulas. In a homogeneous sample, the patients in the experimental group had a normal chest radiograph for a significantly longer time (p = 0.005). The stomas of the experimental group produced significantly less seepage (p = 0.04) and pain (p = 0.004). When the tracheostomy technique was correlated with the stoma, surgical tracheostomy performed in the unit showed significantly more reddening (p < 0.004) and seeping (p < 0.001). We conclude that prolonging cannula changes to every 5 days did not increase the incidence of contamination and reduced the pain of tracheostomized patients.

Bacterial Infections↗
PubMed2003

[Significance of the fluorescein dye disappearance test (FDDT) in the removal of the silicone cannula and prognosis in congenital lacrimal duct obstruction].

OBJECTIVE: Assessment of the prognostic value of the FDD test (fluorescein dye disappearance test) for treatment of congenital occlusion of the lacrimal pathways by means of silicone intubation and for assessment of the time of removal of the cannula. METHOD: The drainage function of the lacrimal pathways was evaluated perspectively in a group of 46 children with inborn occlusion of the lacrimal pathways, aged 1-3 years, treated by means of silicone intubation. The evaluation was made before insertion of the cannula, one week, one month after the operation, during removal of the cannula, one month and one year after its removal. The results of FDDT were compared with the clinical condition and the therapeutic results. RESULTS: In all instances (36 children) where shortly after surgery regression of the signs and symptoms of occlusion occurred and FDDT was 0-1 the long-term result (one year after removal of the cannula) of treatment was favourable. Nine of 11 cases where FDDT 2-3 and signs of occlusion persisted also when the cannula was removed after its removal marked improvement of the symptoms of occlusion occurred or they disappeared and the drainage of the lacrimal pathways was normal. If FDDT suggests during the period with the inserted cannula a satisfactory function of the lacrimal pathways, the prognosis of cure is good and the cannula can be removed already after 6-8 weeks. If during the time with the cannula the impaired drainage function of the lacrimal pathways persists, i.e. FDDT 2-3, it is better to remove the cannula not sooner than after 5-6 months. CONCLUSION: FDDT can serve as a prognostic factor in the treatment of congenital occlusion of the lacrimal pathways by means of a silicone cannula and for assessment of the time of its removal.

Child, Preschool↗
PubMed1991

Development of thrombophlebitis in peripheral veins with Vialon and PTFE-Teflon cannulas: a double-blind, randomised, controlled trial.

A series of 54 normal subjects were randomised to have either a Vialon or a PTFE-Teflon peripheral vein cannula inserted in a vein in each forearm to observe the development of thrombophlebitis. Cannulas were inspected twice daily for up to 5 days to observe the development of three signs, erythema, oedema or hardness and one symptom, pain. Each sign and symptom was recorded twice daily at three points, the cannula insertion site, the mid-point of the cannula and the cannula tip. The degree of change was recorded as less than 1, 1-2 and greater than 2 cm. Any cannula causing any sign greater than 2 cm was removed. By the end of the study over 40% of both types of cannula had been removed. There were no significant differences between the numbers of each type of cannula removed at any time point throughout the duration of the study. There were no significant differences in the amounts of erythema or hardness, but minimally increased swelling was observed at the mid-point of the PTFE-Teflon cannulas (P = 0.022). Despite the theoretical superiority of Vialon as a cannula material, under controlled conditions there appears to be little difference in its inherent capacity to cause the thrombophlebitis.

Adult↗