Stephen George Edward Barker

Evaluation of a needle-free injection system for local anaesthesia prior to venous cannulation

We evaluated a single‐use, disposable, carbon‐dioxide‐powered, needleless injector (J‐Tip, National Medical Products Inc., CA, USA), which is claimed to deliver a virtually painless, subcutaneous injection. Seventy‐two patients undergoing various types of surgery had a large‐bore intravenous cannula inserted prior to induction of general anaesthesia. Three minutes beforehand, a subcutaneous injection of 0.3 ml of 1% plain lidocaine was administered. Subjects were randomly allocated to receive the lidocaine either by the needleless injector or from a conventional syringe and a 25G needle. Pain scores were recorded on injection of the lidocaine and on insertion of the cannula. There was significantly less pain on injection with the needleless injector than with the 25G needle (p < 0.001) but, surprisingly, there was more pain on cannulation (p < 0.001). We conclude that the device certainly delivers a less painful subcutaneous injection than a 25G needle, but perhaps provides less effective skin anaesthesia for venous cannulation at sites where the subcutaneous space is small; its use might be better suited to areas where the subcutaneous space is deeper.

Integrated care pathways for vascular surgery: an analysis of the first 18 months.

Objectives: A review of the use of previously described integrated care pathways (ICPs) established for three elective vascular surgical procedures. Design: A retrospective analysis of information gathered prospectively over an initial 18 month period of use of vascular surgical ICPs. Subjects: Patients admitted to a single vascular unit for “open” repair of abdominal aortic aneurysm (AAA), carotid endarterectomy, or femoropopliteal bypass grafting. Methods: An analysis of variance data, length of stay, and costings after the use of ICPs, compared with previous clinical practice. Results: Variance data were gathered for each of the three procedures. Variances of medication prescribing and delays in discharge were common to all procedures. In particular: (i) gastrointestinal complications were more specific to AAA repair and (ii) wound drains were removed a day later than originally proposed after femoropopliteal bypass. Overall, improved efficiency due to use of ICPs reduced the length of stay for all procedures, which was reflected in a potential cost saving of some 25%. Conclusion: There are clear benefits to the use of ICPs, resulting in more structured, efficient, and cost effective patient care. Recommended changes to current practice based on variance analysis will require continued audit to sustain this “evidence based” approach.

Comparison of a needle-free high-pressure injection system with needle-tipped injection of intracavernosal alprostadil for erectile dysfunction

Patients identified from hospital records as using alprostadil injections for erectile dysfunction were invited to take part in this open crossover study. On alternate weeks eight patients were given intracavernosal needle injections and transdermal needle-free injection of alprostadil in a randomized order. Efficacy of injection and associated pain were assessed and compared for the two methods. Pain produced during injection was significantly greater with the needle-free system than with the needle-tipped injection whilst efficacy was significantly less. Bruising was reported in all except one patient following needle-free injection only. Patient ratings of the needle-free injector were significantly lower than ratings for needle-tipped alprostadil delivery and when asked to express a preference, every patient chose the needle-tipped injection over the needle-free device.

A Comparison of Woven Versus Nonwoven Polypropylene (PP) and Expanded Versus Condensed Polytetrafluoroethylene (PTFE) on Their Intraperitoneal Incorporation and Adhesion Formation

OBJECTIVE To compare known and novel synthetic materials useful for incisional hernia repair and to test independently, whether they justify common perceptions related to their use. METHODS Four types of synthetic materials were implanted in to 12 pigs to compare incorporation histology and adhesion formation 90 d after placement. Woven polypropylene (WPP), nonwoven polypropylene (NWPP), expanded polytetrafluoroethylene (ePTFE). and condensed polytetrafluoroethylene (cPTFE) were placed intraperitoneally (IP). RESULTS Intraperitoneally, WPP became fully peritonealized, but generated thick and plentiful adhesions. NWPP became fully peritonealized and generated filmy and far less numerous adhesions. ePTFE formed some filmy adhesions and did not peritonealize. cPTFE and WPP became fully peritonealized. However, bowel became adherent on raised edges of cPTFE and WPP. CONCLUSION We conclude that NWPP incorporates extremely well intraperitoneally, promotes few adhesions, and its use is likely to be suitable for hernia repair. cPTFE performs well and promotes few adhesions, but to minimize potentially serious complications, its edges must be secured around its entire circumference.

Primary Varicose Veins in the Presence of an Intact Sapheno-Femoral Junction:

Objective: To determine the incidence of primary varicose veins (VVs) occurring in the presence of a competent sapheno-femoral junction. Methods: A retrospective analysis of venous duplex scans was performed for all patients referred to the Vascular Unit, The Middlesex Hospital, London, for assessment of primary VVs, over an 18 month period from 1998 to 2000. Results: One thousand nine hundred and eleven patients with primary VVs referred to hospital for treatment were assessed. Their median age was 52 years (interquartile range 39–64 years). The female:male ratio was 1.92:1. Of these, 43.5% had primary VVs in the presence of a competent sapheno-femoral junction (of whom 70.2% were female). Of those patients with primary VVs in the presence of an incompetent sapheno-femoral junction, 62.4% were female. The incidence of primary VVs did not increase overall with age. The peak incidence for women was between 31 and 60 years of age, whilst that for men was between 51 and 70 years. A similar pattern for age distribution was seen irrespective of sapheno-femoral junction status. Men had a reduced incidence of primary VVs in the presence of an intact sapheno-femoral junction compared with incompetent junctions over the age range of 31–60 years. Conclusions: Primary VVs can readily develop in the presence of a competent sapheno-femoral junction. This occurs most frequently in women below the age of 50 years.

Use of a Needleless Injection System for Digital Ring Block Anesthesia

Digital ring block anesthesia, which is frequently used before surgery for ingrown toenails, is often extremely uncomfortable for patients and can be the most distressing aspect of the procedure. The authors used a novel needleless injection device to induce digital anesthesia before surgery and compared it in terms of patient discomfort and preference with use of a standard needle and syringe for injection in individuals undergoing simultaneous bilateral nail procedures. Use of the needleless device significantly reduced the pain associated with this procedure and was preferred over use of a standard needle and syringe by all individuals. Other potential advantages of a needleless injection system are discussed.

The 'Wound Boot': A preliminary assessment of a novel device for the management of leg ulcers

Objective: A preliminary assessment of a novel device, the ‘wound boot’, in the management of leg ulcers. Procedures: Eight subjects with ulcers wore the boot for 5–14 days. Ulcers were cleaned with saline only. No other dressings were applied. Questionnaires examined comfort and ease of use and asked for suggestions for modifications. Additionally, nurses examined ‘time taken to clean and dress ulcers’ in comparison with standard dressings. Although not a primary end-point, ulcer healing was noted. Results: For all, the boot was comfortable, easy to use and preferable to standard dressings. Ulcer-associated odour was eliminated entirely. A significant reduction was seen in the nursing time taken to clean and dress ulcers. Occasionally, excess exudate was problematic, with the boots absorptive materials insufficient. In two cases, where the ‘boot’ was applied for 14 days, significant wound healing was seen. Conclusions: The prototype ‘boot’ helped significantly in leg ulcer management. Modifications based upon this assessment will allow a second prototype to be evaluated fully.

The effects of heparin on cultured explants of varicose long saphenous vein

Objective: To examine the effects of heparin on smooth muscle cells (SMCs) in explants of varicose, long saphenous vein (LSV). Procedures: Explants of varicose LSV were cultured for 7 days either alone, or with heparin at 10, 100 or 1000 IU/ml (Monoparin). At 7 days, cultured explants were analysed for changes in intimal and medial thickness and by immuno-histochemistry. Comparisons were made with explants at initial isolation and with similar, cultured explants of normal LSV. Results: In normal LSV, by day 7, SMC-derived neo-intimal hyperplasia developed (p<0.01) with an increase in intimal thickness (p<0.02) and a decrease in medial thickness (p<0.001). Heparin at 10 and 100 IU/ml further enhanced this neo-intima formation (p<0.001). In contrast, at 1000 IU/ml, heparin inhibited neo-intima formation. In varicose explants, the pattern of intimal and medial changes was different. At isolation, varicose LSVs had substantially thicker intimal layers (p<0.001). When cultured alone, a thicker media developed (p<0.001) but there was little change in intimal thickness. Heparin at all concentrations had no effect on the thicker medial development seen in controls but did, however, reduce intimal thickness (p<0.005). Conclusions: The response to heparin in explants of varicose LSV is different from that of normal LSV, which is biphasic and complex.

Primary inguinal hernia repair utilizing the mesh ‘plug’ technique

Abstract ‘Tension-free’ mesh repairs, as popularised by Lichtenstein, are being used increasingly in the management of primary inguinal hernia. Introduced more recently, the mesh ‘plug’ technique may enhance further the benefits of such repairs. Twenty six males attending for unilateral, primary, inguinal hernia repair were randomised to have either a Lichtenstein ‘patch’ repair or to undergo a mesh ‘plug’ repair. Ease of technique and operating time were recorded. Patients were given a visual analogue pain-scoring sheet and were asked to record the number of analgesic tablets taken each post-operative day. Patients were reviewed in clinic at 1 and 6 weeks post-operatively, when they were asked their time to return to ‘normal’ activity and time to return to work. Any post-operative complications were noted. The tension-free mesh ‘plug’ repair requires minimal tissue dissection, no herniotomy and is technically straightforward. Patients experienced less post-operative discomfort and returned to ‘normality’ more quickly. The results suggest that the mesh ‘plug’ technique has advantages over the Lichtenstein ‘patch’ repair. A larger trial of this technique should now be undertaken to confirm the results of our pilot study and to assess long term recurrence rates.

An in vitro model for the molecular investigation of varicose veins: Use of cultured explants of human long saphenous vein

Objective: To develop an in vitro model from explants of human varicose veins (VVs). Procedures: Segments of VVs were cultured for up to 14 days with 30% fetal calf serum. At 7 and 14 days, segments were analysed for changes in intima:media thickness and by immunohistochemistry. Comparisons were made with VVs at isolation and cultured explants of normal vein. Results: At isolation, VVs had a significantly thicker intima than normal veins (p<0.001). By day 7 in culture, normal veins developed a significant (smooth muscle cell-derived) ‘neo-intima’ (p<0.006). In contrast, in VVs there was little change in the intima but a significant increase in the thickness of the media (p<0.001). Following 14 days in culture, both the neo-intima in normal veins and thickened media in VVs had regressed. Overall, there was a reduction in the intima:media ratio in VVs by day 14 (p<0.03). Conclusions: Segments of VVs can be maintained in culture for up to 14 days without developing a neo-intima and may provide a suitable model to investigate mechanisms underlying the chronic venous insufficiency of varicosity.