COMPARISON OF THE USE OF THE LARYNGEAL MASK AND FACE MASK BY INEXPERIENCED PERSONNEL

Ten junior doctors with no postgraduate anaesthetic experienceattempted to ventilate the lungs of 50 anaesthetized patients,using either a laryngeal mask or a Guedel airway and face mask.Success was defined as the production of two successive tidalvolumes exceeding 800 ml within 40 s. The failure rate was significantlygreater using the laryngeal mask compared with the face mask(P < 0.05) and the average time was significantly longerwith the laryngeal mask than with the face mask (P < 0.01). The results from this investigation suggest the laryngealmask airway cannot be recommended as a resuscitation devicefor use by inexperienced operators.     

Identification of alcohol-related problems in a general hospital setting: a cost-effectiveness evaluation

Alcohol is a major cause of morbidity and mortality. The prevention of alcohol problems would result in significant savings to the NHS and society. Screening is an important step in preventing problems. This study examines the costs of screening patients for alcohol problems. Over a 21-month period doctors, nurses and a specialist worker screened medical and orthopaedic admissions to the York District Hospital. A cost-effectiveness analysis of screening data was carried out. Costs were measured by time taken to screen and the relative costs of employing different occupational groups. Effects included the screening rates of each occupational group and those identified as at risk. Results suggested a greater positive case identification rate could be achieved by employing a specialist worker, but at greater cost. The cost-effectiveness evaluation helps clarify the resource consequences of a screening programme and can be a useful aid in the decision-making process.     

Clinico-pathological correlation of T3 glottic carcinomas

Controversy surrounds the relative merits of radiotherapy and laryngectomy for the treatment of T₃ glottic carcinoma. In this study of 82 patients with non-irradiated T₃ glottic carcinomas managed by total laryngectomy, 45% had been clinically understaged and were pT₄. There was a significant association between subglottic extension and tracheostomy with understaging. A trend to understage anterior commissure tumours was also evident. Nodal status did not influence understaging and therefore should not determine the choice of treatment of the glottic primary. Laryngectomy is recommended for patients with subglottic extension or a tracheostomy. If radiotherapy is to be used for the remaining tumours, then vigilance against understaging is required.     

Self-association of analgesics in aqueous solution: micellar properties of dextropropoxyphene hydrochloride and methadone hydrochloride

The solution properties of several analgesics including dextropropoxyphene hydrochloride, methadone hydrochloride, dextromoramide acid tartrate and dipipanone hydrochloride have been examined using light scattering, conductivity, vapour pressure osmometry and surface tension techniques. A micellar pattern of association was established for dextropropoxyphene hydrochloride and methadone hydrochloride and critical micelle concentrations and aggregation numbers are reported. The hydrophobic contribution to the free energy of micellization of dextropropoxyphene was determined from measurements of the critical micelle concentration in the presence of added electrolyte.     

Analysis of rhinomanometric data based upon a model of nasal airflow and logarithmic transformation of the data

Estimation of nasal airflow, flow asymmetry and nasal valve stiffness was performed using anterior rhinomanometry in a group of 12 normal subjects and a group of 12 patients suffering from nasal obstruction. The method, based upon a simplified mathematical model of nasal airflow and utilizing logarithmic transformation of inspiratory pressure and flow data, improved the sensitivity and specificity of rhinomanometry and gave a more comprehensive index of nasal function.     

Viscoelastic properties of elastomeric impression materials: polysulphide, silicone and polyether rubbers

Creep compliance measurements were shown to be effective in characterizing the elastic, retarded elastic, and viscous properties of polysulphide, silicone, and polyether impression materials. The test is particularly valuable in that the creep compliance was independent of load, allowing the mechanical properties to be represented by a single total creep compliance curve which can be used to determine the various creep components. The total recovered compliance was shown to be independent of time provided the polymerization had progressed sufficiently before testing was done. The retarded elastic and viscous compliances contributed proportionally to the total creep compliance and thus did not affect the rankings of materials. The viscous compliance of polysulphide A decreased enough after 1 h so that the creep compliance of A and D were not different. The creep compliance measurements showed that the polysulphide materials were the most viscoelastic followed by silicone and polyether impression materials. The polyether was the most nearly ideal elastic material but it had a flexibility comparable to heavy body polysulphide. Of particular interest was the observation that polyether with thinner in ratios up to 1 : 1 by length had no practical effect on the viscoelastic properties.     

Dermatitis due to intravesical mitomycin C: a delayed-type hypersensitivity reaction?

Mitomycin C is an alkylating agent, used by intravesical instillation to treat carcinoma of the bladder. Repeated instillations can induce cystitis and an eczematous eruption affecting the palms, soles and face. If these effects are due to delayed hypersensitivity with sensitization to mitomycin C occurring in the bladder wall, it should be possible to demonstrate antigen-presenting cells in the bladder wall and positive patch tests to the drug. Using an immuno-alkaline phosphatase method we have identified CDI+ cells in bladder epithelium and submucosa and have demonstrated Birbeck granules in a few cells. In further support of our hypothesis it was also possible to demonstrate delayed type hypersensitivity in 13 out of 26 patients who had received mitomycin instillations by applying the allergen as a patch test. These results indicate that the eczematous eruption in this group of patients is most likely a hypersensitivity reaction and that it may be mediated transvesically.     

Self-association of analgesics in aqueous solution: association models for codeine,oxycodone, ethylmorphine and pethidine

Light scattering, vapour pressure osmometry, conductivity and surface tension techniques have been used to examine aqueous solutions of several narcotic analgesics for evidence of association. Contrary to a previous report, no significant association could be detected in solutions of morphine sulphate and codeine phosphate. Other drugs which showed no evidence of aggregation in water included morphine hydrochloride, ethylmorphine hydrochloride, oxycodone hydrochloride and dihydrocodeine tartrate. Self-association of ethylmorphine hydrochloride, oxycodone hydrochloride and codeine phosphate was observed in the presence of 0·5 mol dm^?3 electrolyte, the pattern of association conforming to that of a stepwise association process with all association constants of equal value. The association of pethidine hydrochloride in 0·5 mol dm^?3 sodium chloride could be represented by an association scheme in which association constants K_N increased sequentially with aggregation number N according to the relation K_N = K(N — 1)/N.     

Characterization of nasal airflow

Nasal airflow and trans-nasal pressure difference was measured by active anterior rhinomanometry in 24 subjects. An analysis was undertaken to determine the ‘goodness of fit’ of two models used to characterize nasal airflow, one model by Broms and the other by O’Neill and Tolley. A judicious approach to choice of fit criterion led to the conclusion that the latter model provided a more accurate characterization of nasal airflow. Additionally this model may be useful to quantify alar valve stiffness. A portable computerized system incorporating the use of the model has been developed and is currently in use.