A randomised, double-blind, placebo-controlled, comparative study of topical skin analgesics and the anxiety and discomfort associated with venous cannulation.

OBJECTIVES: To compare the effect of topical skin anaesthetic agents on the discomfort and anxiety associated with venous cannulation. DESIGN: Randomised, double-blind, placebo-controlled, within subject, volunteer trial. METHODS: 20 healthy volunteers underwent venous cannulation on three separate occasions having received topical skin application of either 4% amethocaine gel (Ametop), 5% eutectic mixture of lidocaine and prilocaine (EMLA) or E45 cream (placebo). Visual analogue and verbal rating scales were used to assess pain and anxiety associated with the venous cannulation, and anticipated anxiety for future cannulation, under each drug condition. RESULTS: Subjects were aged 22-53 years (mean 32.8 years). The mean visual analogue scores (VAS) for discomfort were found to be significantly lower (p< 0.001) with Ametop (VAS = 18mm) and EMLA (VAS = 29mm) compared with the control (VAS = 38mm). There was a positive correlation (R2 = 72%, p<0.001) between discomfort and the predicted anxiety if cannulation was to be repeated with the same cream. With the placebo a positive correlation (R2 = 19.8%, p = 0.05) was found between the level of anxiety before cannulation and the level of discomfort recorded. CONCLUSIONS: Ametop and EMLA topical anaesthetic agents produce effective skin analgesia for venous cannulation. The use of topical analgesia can reduce perceived anxiety about future cannulation procedures. This has application in the management of anxious patients undergoing intravenous sedation, suggesting that topical analgesia prior to venous cannulation may significantly aid anxiolysis.

Range of validity of alpha and beta for a generalized diversity index H (alpha, beta) due to Good.

Good (I. J. Good, Biometrika 40 (1953) 237; J. Am. Statist. Assoc. 77 (1982) 561) proposed a diversity index H (alpha, beta), defined for non-negative integer alpha and beta, which generalized the well-known indices of Shannon and Simpson. In this paper we further generalize Good's index by allowing the parameters alpha and beta to take values in the real plane. For two simple properties which a 'good' diversity index should possess, we determine the range of valid alpha and beta values for this generalized index.

Sequential antibiotic therapy for acne promotes the carriage of resistant staphylococci on the skin of contacts.

The selection of a predominantly resistant staphylococcal skin flora in acne patients during antibiotic treatment has been extensively documented. This study sought to determine whether antibiotic therapy for acne had any effect on skin carriage of resistant coagulase-negative staphylococci (CNS) by close contacts of treated patients. Bacterial samples were obtained using a scrub wash technique from facial skin of 41 contacts (parents, siblings or partners) of patients who had been treated with at least three different antibiotics over a minimum period of 2 years. Samples were also obtained from 41 control subjects who had no known contact with any antibiotic treated acne patient. None of the contacts or controls had received any antibiotic therapy in the preceding two years. The number, percentage and prevalence of CNS resistant to each of seven antibiotics was estimated by plating serial ten-fold dilutions of wash fluid directly onto antibiotic-containing and antibiotic-free medium. Significantly more contacts than controls carried strains resistant to erythromycin, clindamycin, fusidic acid, trimethoprim and chloramphenicol as well as more multiply resistant strains (P < 0.05, chi 2). The number and percentage of staphylococci resistant to tetracycline, erythromycin, clindamycin, fusidic acid and chloramphenicol were also significantly raised (P < 0.05, Mann-Whitney U-test) in contacts. Only aminoglycoside resistance was not increased by any of the above criteria. These observations provide evidence that sequential antibiotic therapy for acne exerts selective pressure for increased skin carriage of resistant CNS not only in patients but also in their close contacts.

The chest radiograph in cystic fibrosis: a new scoring system compared with the Chrispin-Norman and Brasfield scores.

BACKGROUND: Scoring systems for the chest radiograph in cystic fibrosis are used to compare patients and different treatment regimens, and to monitor respiratory disease in individual patients. The Northern chest radiograph score was designed to allow one person to assess the radiological features of lung involvement in cystic fibrosis in as simple, rapid and equally reproducible manner as the established Chrispin and Norman, and Brasfield scoring systems. METHODS: Forty five chest radiographs were scored by 10 physicians with a special interest in cystic fibrosis according to the Brasfield and Northern methods, and by five pairs of physicians according to the Chrispin-Norman criteria. Three individuals and two pairs rescored the radiographs after an interval of 3-5 months. The Northern score was performed with and without a lateral view, using the original posteroanterior radiograph. RESULTS: The Northern score showed a better agreement between observers for the ranking of the radiographs. It was equally well related to respiratory function tests, the Shwachman-Kulczycki score of overall clinical status, and in its discrimination between different radiographs as the other two scoring systems. The Northern score performed equally well with or without a lateral film. CONCLUSIONS: The Northern system fulfils the requirements of a chest radiograph score more successfully than the Chrispin-Norman or Brasfield systems, and does not require a lateral film.

Effect of warfarin on plasma concentrations of vitamin K dependent coagulation factors in patients with stable control and monitored compliance.

There is a discrepancy in the results of reported studies of levels of vitamin K dependent coagulation factors in patients on warfarin therapy. This may have arisen partly because of the problem of assuring compliance with therapy in outpatients. The plasma concentrations of the vitamin K dependent clotting factors II, VII, IX and X were studied in 23 outpatients whose adherence to prescribed warfarin therapy was determined using a pharmacological indicator of compliance. In these patients, who were shown to have consistently good compliance and stable anticoagulant control over a period of 3-6 months, the activities in plasma of the four coagulation factors were not equally suppressed. Factor IX levels were significantly greater than those of factor VII (P less than 0.0001) which in turn were significantly greater than the levels of factor II (P less than 0.0001) or factor X (P less than 0.0001). There was no significant difference between the levels of factors II and X which were depressed to a similar extent. The proportion of variability of the International Normalized Ratio (INR) explained by linear regression was 51-77% and a model was derived to predict the INR from the mean of the levels of the four clotting factors. The concentrations of the coagulation factors II, VII, IX and X are likely to be highly dependent on the degree of compliance with warfarin therapy which should be taken into account when investigating the behaviour of these factors.

Dynamic compressive properties of human lumbar intervertebral joints: a comparison between fresh and thawed specimens.

A comparison between the dynamic compressive properties of human lumbar intervertebral joints when fresh and after a period of deep frozen storage was made. Physiologically relevant loads of -750 +/- 250 N were applied in axial compression with the joint constrained against bending, over a frequency range of 0.01-10 Hz. Frozen storage was found not to affect the compressive stiffness or hysteresis of the seven joints. The magnitude of the observed changes in mean values were small, less than 1% decrease in the compressive stiffness and less than 1% increase in hysteresis after deep frozen storage.