In the interest of patients: an evidence-based assessment of the safety of vinyl infusion care devices.

Decisions in virtually every sector of modern healthcare are increasingly guided by the doctrine of evidence-based medicine. This includes the choice of materials and medical devices used in life-sustaining procedures such as infusion therapy. Environmental activists contend that devices made from plasticized vinyl, which are ubiquitous in healthcare settings, constitute a health risk to patients and should be deselected for these and other procedures. An evidence-based assessment refutes these allegations and makes clear that for most applications, vinyl remains superior to alternative materials in terms of safety and performance.

Spontaneous snapping of an Implanon in two halves in situ.

A 30-year-old woman presented at our family planning clinic for Implanon removal and reinsertion. At the time of presentation the patient's weight was 148 kg. The Implanon was fitted in July 2000 (i.e. 35 months previously) when her weight was 138.5 kg. The patient was very happy with the contraceptive method. She was aware that her Implanon had snapped in half about 2 months ago. There was no aggravating factor such as weightlifting associated with this incidence.

A randomized multicenter study comparing the efficacy and bleeding pattern of a single-rod (Implanon) and a six-capsule (Norplant) hormonal contraceptive implant.

To compare the contraceptive efficacy, tolerability, and bleeding patterns, 200 healthy female volunteers received, in an open, comparative, randomized, multicenter study in China, either a single-rod (Implanon) or a six-capsule (Norplant) contraceptive implant for 2 years with an optional extension of up to 4 years. Women were exposed to Implanon for 341.6 woman-years and Norplant for 329.1 woman-years. There were no pregnancies during the study. Per 90-day reference period, the median number of bleeding/spotting days with Implanon decreased from 33.5 in the first period to 19.0-21.5 days in the last year. Similarly, with Norplant, the median number of bleeding/spotting days decreased from 34.5 to 18.0-23.0 days, respectively. The number of bleeding/spotting episodes during year 1 was 2.0 per 90-day reference period with Implanon and 3.0 per period with Norplant (p < 0.05 for periods 1-4). For the remaining 90-day periods, there was no statistical difference between the two groups. In general, there was less frequent bleeding with Implanon compared with Norplant, whereas the incidences of amenorrhea and infrequent bleeding were higher with Implanon than with Norplant. The mean overall incidence of prolonged bleeding fell markedly during the study, from 66.0% in reference period 1 to 27.3% in period 16 with Implanon and from 69.0% to 21.7% with Norplant, respectively. The most common adverse events were related to disturbed bleeding patterns, which were also the major reasons for discontinuation (Implanon n = 8; Norplant n = 14). Normal menses returned in almost all subjects within 3 months after removal of the implants. Implanon was inserted in a mean time of 0.61 min and Norplant in 3.90 min (p < 0.001). Similarly, the mean time required to remove the implant was significantly shorter for Implanon than for Norplant (2.18 min vs 11.25 min, p < 0.001). The maximum time required for removal of the implant was 10 min for the Implanon group and 60 min for the Norplant group. In both groups, blood pressure and hemoglobin were not affected, whereas body weight tended to increase. It can be concluded that both contraceptive systems demonstrated excellent contraceptive efficacy and were well tolerated. Compared with Norplant, there was less frequent bleeding with Implanon, whereas the incidence of infrequent bleeding and amenorrhea was higher. Implanon was significantly quicker to insert and to remove than was the multiple capsule system.

PIP: This study compares the contraceptive efficacy and bleeding patterns of a single-rod (Implanon) and a six-capsule (Norplant) contraceptive implant for 2 years, with an optional extension of up to 4 years, among 200 healthy female volunteers in China. Women were administered with Implanon for 341.6 woman-years and Norplant for 329.1 woman-years. No pregnancies occurred during the study, demonstrating excellent contraceptive efficacy. The median number of bleeding/spotting (B/S) days with Implanon decreased from 33.5 in the first period to 19.0-21.5 days in the last year. With Norplant, the median number of B/S days decreased from 34.5 to 18.9-23.0 days. There was less frequent bleeding with Implanon than with Norplant. The most common adverse effects were related to disturbed bleeding patterns, which were also the main reasons for discontinuation (Implanon, n = 8; Norplant, n = 14). Normal menses returned in almost all subjects within 3 months after removal of the implants. Lastly, Implanon required less time for insertion and removal as compared to Norplant.

The pharmacodynamics and efficacy of Implanon. An overview of the data.

Implanon is a long-acting reversible contraceptive method, consisting of a single rod that is applied subdermally. Ovulation inhibition was determined by serum progesterone (P) levels and ultrasound scanning (USS) of the ovaries. Ovarian function was further assessed by serum estradiol (E2) levels. The effects of Implanon on serum gonadotropin levels (follicle-stimulating hormone [FSH] and luteinizing hormone [LH]) and on cervical mucus were also investigated, by means of Insler scores and sperm penetration tests. The effect of the endometrium was assessed by endometrial biopsies and USS. The Pearl index was calculated over 13 studies performed according to Good Clinical Practice (GCP), including 1716 women using Implanon. Return of ovulation after implant removal was determined by P levels and USS of the ovaries. The contraceptive efficacy of Implanon was high, with zero pregnancies during 53,530 cycles (4103 woman-years), resulting in a Pearl index of 0.0 (95% confidence interval, 0.00-0.09). This was achieved by inhibition of ovulation, which was reflected by suppressed P levels, as the primary mode of action. Ovulation was inhibited, but otherwise ovarian activity was still present (follicle growth, E2 synthesis). The FSH serum concentrations were only slightly lower than preinsertion levels and LH surges were prevented. The viscosity of the cervical mucus was increased. The endometrium was thin but not atrophic; it showed primarily inactive or weak proliferation. Return of ovulation after removal of Implanon was rapid.

The effect of the type and technique used for impression making on the accuracy of elastomeric impression materials.

The effect of the technique used for impression making on the accuracy of three types impression materials, (vinyl silicons, condensation silicons and polyether elastomers) was evaluated. Three main impression making techniques were used. Impressions were made for stainless steel master model. The impressions were poured after thirty minutes with improved stone into stone casts. Accuracy was assessed by comparing seven measurements of the master model to their corresponding on the stone case produced. A travelling microscope of 0.001 mm accuracy was used for measurements. The results of the study have shown that all elastomeric impression materials produced accurate impression but with significant difference among them. The polyether was more accurate than silicon impressions. The technique used for making the impression had more effect on the relative accuracy than the type of the material. Reference for the best technique for each type was concluded.

Leakage of latex and vinyl exam gloves in high and low risk clinical settings.

The purpose of this study was to compare leakage rates of used latex and vinyl examination gloves from high and low risk clinical units. A total of 4838 latex and 1008 vinyl examination gloves were collected and tested by the Food and Drug Administration (FDA) watertight leak test: three brands of latex [Brand A: n = 2920; Brand B: n = 284; Brand C: n = 1634; and one brand of vinyl gloves (Brand D: n = 1008]. Seventy percent of latex gloves and 46.7% of vinyl gloves were collected from the high risk units. In general, there were no significant differences in leakage rates for vinyl gloves between high and low risk units. However, latex gloves leaked significantly more often at stress levels 2 and 3 from the high risk units as compared to the low risk units (X2 = 24.6, p < .0001). Regardless of level of stress and duration worn, 85.3% (860/1008) of used vinyl gloves and 18.4% (891/4838) of used latex gloves leaked, p < .001). There were significant differences in leakage rates between the three brands of latex gloves (Brand A, 9.8%; Brand B, 25.1%; Brand C, 30.9%, p < .001). Although latex gloves leaked slightly more frequently as stress level increased, glove material (latex or vinyl) and brand of glove were the most important predictors of leakage.

Flexure fatigue of 10 commonly used denture base resins.

The flexure fatigue properties of 10 denture base resins (four different types) were tested. Each specimen underwent two-way testing in a water bath maintained at 37 degrees +/- 1 degree C. A load of 3,650 gm was applied a 342 flexures per minute until the specimen broke. The resin types listed in order of increasing resistance to flexure fatigue are polymethylmethacrylate (PMM) pour resins, PMM thermosetting resins, vinyl resins, and a PMM grafted resin. Although small samples size and scatter of results limit broad application of this data, it is of some significance that the grafted resin Lucitone 199 tended to withstand repeated flexure when compared to the other resins.

An embouchure aid for clarinet and saxophone players.

An embouchure aid was constructed as a means of bringing relief to the many clarinet and saxophone players who suffer chronic lip irritation as the result of playing their instruments. The device, a removable vinyl plastic matrix to be worn while playing, was designed to fit over the mandibular anterior teeth, thus relieving the pressure of the incisal edges of the teeth against the mucous membrane inside the lower lip. Tested in daily use by clarinet and saxophone players for a one-year period, the matrix proved immediately effective in eliminating lip irritation. Its unique design and construction gives it the additional advantages of being highly durable, as well as technically simple to fabricate and easy to fit.