Airtraq vs standard laryngoscopy by student paramedics and experienced prehospital laryngoscopists managing a model of difficult intubation

Two consecutive, randomised, cross-over trials compared intubation success rates in third-year paramedic students and experienced prehospital practitioners using the Airtraq or a Macintosh laryngoscope with flexible stylet in a manikin model of a Cormack and Lehane grade III/IV laryngoscopic view. First-time intubation rates for the Macintosh and Airtraq for students were 0/23 (0%) vs 10/23 (44%) (44% difference, 95% CI 26-63%, p < 0.001) and for experienced laryngoscopists were 14/56 (25%) vs 47/56 (84%) (59% difference, 95% CI 42-72%, p < 0.0001), respectively. First-time oesophageal intubation rates for students were 15/23 (65%) vs 3/23 (13%) (-52% difference, 95% CI -25 to -72%, p < 0.001) and for experienced practitioners 9/56 (16%) vs 0/56 (0%) (-16% difference, 95% CI -9 to -28%, p = 0.0014). Student paramedics and experienced prehospital laryngoscopists managing a manikin model of a grade III/IV view had increased first-time intubation rates and had lower rates of oesophageal intubation with the Airtraq compared with a standard laryngoscope.

Retraining: Can do, will do? A practical guide to process and pitfalls

This article reports the lessons learnt from a period of retraining and from discussion with others who have been involved in a similar process. The conclusions are that retraining should only be undertaken once there is full agreement between all parties involved that it is necessary and feasible. There must also be agreement in advance of the criteria which will constitute successful retraining, and the actions which will be taken to ensure the rapid return of the retrainee to the type of practice which is being offered and has been accepted. The process of retraining requires especially close supervision and is very stressful for the retrainee. It is likely that this should only be undertaken in units specially staffed and funded to accommodate this type of work.

Neuropathological consequences of delivering an adenoviral vector in the rat brain

BACKGROUND

Adenoviruses have many advantages as vehicles for gene delivery to the central nervous system (CNS) and retrograde transport of vectors to axonally linked sites has been postulated as a method for targeting neurons in remote brain regions. To investigate optimisation of this we injected different doses of vector and have documented the neuropathological side effects.

METHODS

Increasing doses of a first-generation adenoviral vector, expressing the lacZ gene, were inoculated in the rat striatum and beta-galactosidase expression was examined at the primary and secondary sites. Subsequently, at the highest dose of vector, transgene expression, the inflammatory response, tyrosine hydroxylase (TH) expression and the rotational behaviour of animals were studied over time.

RESULTS

When a high dose of an adenoviral vector was delivered to the rat striatum, high levels of transgene expression were seen at 5 days in the injection site and in the substantia nigra. Smaller doses gave lower levels of expression with little expression detectable in the substantia nigra. At later time points, with the high dose, a marked reduction in transgene expression was detected and was accompanied by cytopathic damage, a strong inflammatory response and animal weight loss. This was associated with depletion in TH levels and abnormal motor behaviour in animals.

CONCLUSIONS

Neuropathological damage in the dopaminergic system, caused by high doses of adenoviral vectors, has not previously been documented. To minimise damage and prolong transgene expression, it is important that the dose of vectors to be delivered is carefully optimised.

The Aristotle score: a complexity-adjusted method to evaluate surgical results1

OBJECTIVES

Quality control is difficult to achieve in Congenital Heart Surgery (CHS) because of the diversity of the procedures. It is particularly needed, considering the potential adverse outcomes associated with complex cases. The aim of this project was to develop a new method based on the complexity of the procedures.

METHODS

The Aristotle project, involving a panel of expert surgeons, started in 1999 and included 50 pediatric surgeons from 23 countries, representing the EACTS, STS, ECHSA and CHSS. The complexity was based on the procedures as defined by the STS/EACTS International Nomenclature and was undertaken in two steps: the first step was establishing the Basic Score, which adjusts only the complexity of the procedures. It is based on three factors: the potential for mortality, the potential for morbidity and the anticipated technical difficulty. A questionnaire was completed by the 50 centers. The second step was the development of the Comprehensive Aristotle Score, which further adjusts the complexity according to the specific patient characteristics. It includes two categories of complexity factors, the procedure dependent and independent factors. After considering the relationship between complexity and performance, the Aristotle Committee is proposing that: Performance = Complexity x Outcome.

RESULTS

The Aristotle score, allows precise scoring of the complexity for 145 CHS procedures. One interesting notion coming out of this study is that complexity is a constant value for a given patient regardless of the center where he is operated. The Aristotle complexity score was further applied to 26 centers reporting to the EACTS congenital database. A new display of centers is presented based on the comparison of hospital survival to complexity and to our proposed definition of performance.

CONCLUSION

A complexity-adjusted method named the Aristotle Score, based on the complexity of the surgical procedures has been developed by an international group of experts. The Aristotle score, electronically available, was introduced in the EACTS and STS databases. A validation process evaluating its predictive value is being developed.

Tobramycin and gentamicin are equally safe for neonates: results of a double-blind randomized trial with quantitative assessment of renal function

The frequent use of aminoglycosides in neonates led us to compare tobramycin and gentamicin because some studies in adults and animals suggested a safety advantage for tobramycin. In a randomized, double-blind comparison, 50 infants < or = 3 days old received either tobramycin or gentamicin, 2.5 mg/kg/12 hr, for a mean of 8 days. The groups were similar for gestational age, birth weight, underlying disease, Apgar score, clinical condition, renal function, and concurrent use of other drugs. Trough and postdose serum concentrations of both drugs were similar in each weight group. Renal status at onset, during or up to 2 wk after therapy was also similar, as judged by urinalysis, serum creatinine, fractional excretion of Na, urine N-acetyl-beta-glucosaminidase, and urine to serum creatinine ratio. Nephrotoxicity occurred in four infants (13%) receiving tobramycin and three infants (15%) receiving gentamicin. No otoxicity, as measured by auditory brainstem response, was noted in either group. Tobramycin offered no safety advantages over gentamicin in neonates, and the choice between the agents should be based on other considerations, such as susceptibility of the pathogen and cost.

Characterization of the radical product formed from the reaction of nitric oxide with the spin trap 3,5-dibromo-4-nitrosobenzene sulfonate

Previously, 3,5-dibromo-4-nitrosobenzene sulfonate (DBNBS) has been used in combination with electron paramagnetic resonance (EPR) spectrometry to trap nitric oxide (NO(*)). The reaction between DBNBS and NO(*) yields a radical product which gives rise to an EPR signal consisting of three lines with an A(N) = 0.96 mT, but the structure of this product is unknown. A two-stage high-performance liquid chromatography fractionation was performed to isolate the radical product from the other components in the DBNBS/NO(*) reaction mixture. The fractions containing the radical product were identified by the presence of the three-line EPR signal, and then these fractions were analyzed by negative ion fast atom bombardment-mass spectrometry (FAB-MS). Collectively, the FAB-MS data suggested that the radical product is the monosodium electrostatic complex with the dianion, bis(2,6-dibromo-4-sulfophenyl) nitroxyl. Analysis of the Gaussian and Lorentzian linewidths of the EPR signal suggested that bis(2,6-dibromo-4-sulfophenyl) nitroxyl molecules may group together to form micelles. Further studies also indicated that significant amounts of nitrogen and nitrate were produced during the reaction between DBNBS and NO(*). A reaction scheme consistent with these results is presented.

Relationship between HIV-1 Env subtypes A and D and disease progression in a rural Ugandan cohort

OBJECTIVE

To investigate the role of HIV-1 envelope subtypes on disease progression in a rural cohort of Ugandan adults where two major HIV-1 subtypes (A and D) exist.

METHODS

Participants of a clinical cohort seen between December 1995 and December 1998 had blood collected for HIV-1 subtyping. These included prevalent cases (people already infected with HIV at the start of the study in 1990) and incident cases (those who seroconverted between 1990 and December 1998). HIV-1 subtyping was carried out by heteroduplex mobility assay and DNA sequencing in the V3 env region. Disease progression was measured by the rate of CD4 lymphocyte count decline, clinical progression for the incident cases as time from seroconversion to AIDS or death, to first CD4 lymphocyte count < 200 x 10(6)/l and to the World Health Organization clinical stage 3. All analyses were adjusted for age and sex.

RESULTS

One hundred and sixty-four individuals, including 47 prevalent and 117 incident cases, had V3 env subtype data of which 65 (40%) were subtyped as A and 99 as D. In the incident cases, 44 (38%) were subtyped as A and 73 as D. There was a suggestion that for most end-points A had a slower progression than D. The cumulative probability of remaining free from AIDS or death at 6 years post-seroconversion was 0.72 [95% confidence interval (CI), 0.50 to 0.85] for A and 0.58 (95% CI, 0.42 to 0.71) for D, and the adjusted hazard ratio of subtype D compared to A was estimated to be 1.39 (95% CI, 0.66 to 2.94; P = 0.39). The estimated difference in rates of decline in square root CD4 lymphocyte counts was -0.41 per year (95% CI, -0.98 to 0.15; P = 0.15).

CONCLUSION

This study suggests that although subtype A may have a slower progression than D, HIV-1 envelope subtype is not a major factor in determining the progression of HIV-1 disease in a rural population in Uganda.

A cohort mortality study of U.K. carbon black workers, 1951-1996

BACKGROUND

Carbon black, a powdered form of elemental carbon is used in the manufacture of rubber products, paints, plastics, and inks. In 1974, the Health and Safety Executive initiated a cohort mortality study on possible carcinogenic effects on carbon black workers.

METHODS

The mortality of a cohort of 1,147 male manual workers from five U.K. factories manufacturing carbon black was investigated for the period 1951-1996. All subjects were employed in the carbon black industry for 12 months or more, and all were first employed before 1975. Limited work histories were used to calculate estimates of individual cumulative exposure to carbon black, using a job-exposure matrix derived by the study team.

RESULTS

Based on serial rates for the general population of England and Wales, significantly elevated mortality was observed in the main study cohort for all causes (Obs 372, Exp 328.7, SMR 113, P < 0.05) and for lung cancer (Obs 61, Exp 35.3, SMR 173, P < 0.001). There were highly elevated lung cancer SMRs at two of the factories, and unexceptional SMRs at the remaining three factories. There was no indication of lung cancer SMRs increasing with period from first employment. Poisson regression analyses failed to find significant trends of lung cancer risks increasing either with cumulative exposure to carbon black (4 levels) or with duration of employment at the participating factories (4 levels).

CONCLUSIONS

Confident interpretation of the elevated SMRs found for lung cancer in two of the factory subcohorts is not possible but the study has been unable to link cumulative exposure to carbon black with elevated risks of lung cancer.

n-3 fatty acid deficiency decreases phosphatidylserine accumulation selectively in neuronal tissues

We have previously shown that the docosahexaenoate (22:6n-3) status in membrane phospholipids influences the biosynthesis and accumulation of phosphatidylserine (PS) in brain microsomes and C6 glioma cells. In the present study, we investigated whether the observed effect of membrane docosahexaenoic acid status on PS accumulation is universal or occurs specifically in neuronal tissues. We observed that rat brain cortex, brain mitochondria, and olfactory bulb, where 22:6n-3 is highly concentrated, contain significantly higher levels of PS in comparison to liver and adrenal, where 22:6n-3 is a rather minor component. Phospholipid molecular species analysis revealed that in brain cortex, mitochondria, and olfactory bulb 18:0,22:6n-3 was the most abundant species representing 45-65% of total PS. In nonneuronal tissues such as liver and adrenal, 18:0,20:4n-6 was the major PS species. Dietary depletion of n-3 fatty acids during prenatal and postnatal developmental periods decreased the brain 22:6n-3 content by more than 80%, with a concomitant increase in 22:5n-6 in all tissues. Under these conditions, an approximately 30-35% reduction in total PS in rat brain cortex, brain mitochondria, and olfactory bulb was observed, while PS levels in liver and adrenal were unchanged. The observed reduction of PS content in neuronal membranes appears to be due to a dramatic reduction of 18:0,22:6n-3-PS without complete replacement by 18:0,22:5n-6-PS. These results establish that variations in membrane 22:6n-3 fatty acid composition have a profound influence on PS accumulation in neuronal tissues where 22:6n-3 is abundant. These data have implications in neuronal signaling events where PS is believed to play an important role.

Molecular epidemiology of HIV type 1 in a rural community in southwest Uganda

The molecular epidemiology of a population-based cohort in a cluster of 15 villages in southwestern Uganda was investigated by sequencing part of the p24 gag gene and performing heteroduplex mobility assays (HMAs) of the V3 region of the env gene. Sequence and HMA data, obtained for 69 and 88 proviruses, respectively, showed that the clade A and D viruses were present at a ratio of about 0.67:1. No other clades were detected. Thirteen (22%) of 59 proviruses for which both gag and env data were obtained appeared to be recombinants. Although both clade A and D viruses were present in 13 of the villages, their distribution was unequal: for example, from env data 59% of clade A viruses were found in the eastern villages, compared with only 27% of clade D viruses. Phylogenetic (maximum likelihood) analysis of the p24 gag sequences showed a total of five clusters supported by bootstrap resampling values above or close to 75%. Four clusters were sexual partners, but there was no known sexual contact between the persons in the other cluster. The DNA sequences showed between 0.5 and 8.3% divergence from the cohort clade A or D consensus sequences. The sequences were not closely related to those published for other clade A or D proviruses.

A further cohort study of workers employed at a factory manufacturing chemicals for the rubber industry, with special reference to the chemicals 2-mercaptobenzothiazole (MBT), aniline, phenyl-beta-naphthylamine and o-toluidine

OBJECTIVES

To investigate mortality and cancer morbidity in workers from a factory manufacturing chemicals for the rubber industry.

METHODS

The mortality (1955-96) and cancer morbidity experience (1971-92) of a cohort of 2160 male production workers from a chemical factory in north Wales were investigated. All subjects had at least 6 months employment at the factory and some employment in the period 1955-84. Detailed job histories were abstracted from company computerised records and estimates of individual cumulative exposure to 2-mercaptobenzothiazole (MBT) and its derivatives were obtained, with a job exposure matrix derived by a former factory hygienist. Durations of employment in the aniline, phenyl-beta-naphthylamine (PBN) and o-toluidine departments were also calculated. Two analytical approaches were used, indirect standardisation and Poisson regression.

RESULTS

Based on serial rates for the general population of England and Wales, observed mortality for the total cohort was close to expectation for all causes (observed (obs) deaths 1131, expected (exp) deaths 1114.5, standardised mortality ratio (SMR) 101), and for all cancers (obs 305, exp 300.2, SMR 102). There was a significant (p < 0.05) excess mortality from cancer of the bladder in the 605 study subjects potentially exposed to one or more of the four chemicals being investigated (obs 9, exp 3.25, SMR 277, 95% confidence interval (95% CI) 127 to 526). This excess was dependent primarily on deaths occurring > 20 years after first exposure in those who started employment before 1955 (obs 7, exp 1.25, SMR 560, 95% CI 225 to 1154, p < 0.001). There were 30 subjects in the total study cohort who, on the basis of death certificates or cancer registration particulars, had had malignant bladder cancer. In separate analyses of the four exposure history variables (after adjustment for age), Poisson regression showed significant positive trends for risk of notification of bladder cancer increasing with cumulative duration of employment in the PBN (p < 0.001) and o-toluidine departments (p < 0.01); similar findings were not obtained for cumulative exposure to MBT or for duration of employment in the aniline department. In a simultaneous analysis of all four chemical exposure variables, a significant positive trend remained for duration of employment with exposure to PBN (p < 0.05). Further analyses of all cases of bladder cancer (malignant and benign diagnoses) used employment histories lagged by 15 years; similar findings were obtained.

CONCLUSIONS

It seems likely that some members of this cohort have had occupational bladder cancer. Confident interpretation is difficult because of small numbers in the exposed subcohorts, relatively crude measures of exposure assessment for the four chemicals under study, and presence of unconsidered potential chemical confounders. The simplest interpretation of the findings about bladder cancer may be that PBN (or a chemical reagent or chemical intermediate associated with its production at this factory in the 1930s and 1940s) is a bladder carcinogen. Priority should be given, however, to obtaining information on the cancer experience of other working populations exposed to PBN or to o-toluidine.

Maternal occupational exposure to electromagnetic fields before, during, and after pregnancy in relation to risks of childhood cancers: findings from the Oxford Survey of Childhood Cancers, 1953-1981 deaths

BACKGROUND

The concern that maternal exposure to electromagnetic fields (EMF) might be related to childhood cancer risks, particularly leukemia risks.

METHODS

Maternal occupational data already collected as part of the Oxford Survey of Childhood Cancers have been reviewed. Information on occupations held before, during, and after the pregnancy was sought for 15,041 children dying of cancer in Great Britain in the period 1953-1981, and for an equal number of matched controls. Each period of working was classified under one of five headings: (1) sewing machinist; (2) textile industry workers (other than sewing machinists) with likely exposures to EMF; (3) other machinists and other jobs with likely "higher" EMF exposure; (4) other jobs with likely exposure to some EMF, and (5) jobs with little potential for EMF exposure.

RESULTS

Relative to risks in the children of mothers who held occupations with little potential for EMF exposure during pregnancy (a category that included housewives), risks of all childhood cancers were close to unity both for the children of sewing machinists (22 case and 31 control mothers, RR 0.72, 95% CI 0.42 to 1.25) and for the children of other machinists with likely "higher" EMF exposures (44 case and 47 control mothers, RR 0.93, 95% CI 0.61 to 1.41). Corresponding risks for all childhood leukemias and for all childhood brain cancers were similarly unexceptional. Simultaneous adjustment for social class, maternal age at birth of child, and sibship position had little effect.

CONCLUSIONS

The study findings did not indicate that maternal occupational exposure to EMF during pregnancy is a risk factor for childhood leukemias, childhood brain cancers, or the generality of all childhood cancers.

Paediatricians: referral rates and speech pathology waiting lists

OBJECTIVE

This study aimed to examine paediatricians' training in and understanding of communication development and disabilities and their attitudes to speech pathology waiting lists and management practices. The relationship between these factors and referral rates was also investigated.

METHODOLOGY

A total of 229 paediatricians registered with the Australian College of Paediatrics participated in the study in November 1996. They answered 15 multiple-choice questions designed to collect demographic information and data pertaining to their training and understanding of communication development and disabilities. The survey also obtained data on referral rates to public and private speech pathology services and on paediatricians' perceptions of speech pathology waiting lists and possible management strategies.

RESULTS

Referral rate to public and private speech pathology services was found to be associated with the quality of paediatricians' training in and knowledge of communication development and disabilities. Paediatricians who had regular contact with speech pathologists were also more likely to make more referrals. Waiting lists had a negative influence on referral rate. Treatment rather than assessment waiting lists were preferred. Paediatricians believed the best solution to speech pathology waiting lists was an increase in staffing levels particularly in community health centres. Respondents reported that 1-4 months was an acceptable time to wait for speech pathology care and indicated the order of importance of factors for prioritising children.

CONCLUSIONS

The results have important implications for developing best practice models for improving referral processes and access to speech pathology services for children with communication disabilities.

Increasing fruit and vegetable consumption among callers to the CIS: results from a randomized trial

BACKGROUND

Results are reported from a large randomized trial designed to increase fruit and vegetable consumption among callers to the Cancer Information Service (CIS).

METHODS

CIS callers assigned to the intervention group received a brief proactive educational intervention over the telephone at the end of usual service, with two follow-up mailouts. Key educational messages and print material derived from the NCI 5 A Day for Better Health program were provided to intervention subjects. Subjects were interviewed by telephone at both 4-week (n = 1,672) and 4-month (n = 1,286) follow-up.

RESULTS

A single-item measure of fruit and vegetable consumption revealed a significant intervention effect of approximately 0.65 servings per day at 4-week follow-up (P < 0.001) and 0.41 servings per day at 4-month follow-up (P < 0.001). Using a seven-item food frequency measure that was also included in the 4-month interviews, a similar intervention effect of 0.34 servings per day was obtained (P = 0.006). The vast majority of CIS callers (88%) endorsed the strategy of providing 5 A Day information proactively.

CONCLUSIONS

A brief educational intervention delivered to CIS callers at the end of usual service was associated with an increase in self-reported fruit and vegetable intake.

Occupational urothelial tumours: a regional case-control study

OBJECTIVE

To investigate the role of occupational exposures in the risk of developing urothelial cancer.

MATERIALS AND METHODS

Occupational histories, obtained using a self-administered questionnaire, for 803 patients with urothelial cancer (first diagnosed 1991-93) were compared with similar information for 2135 matched controls. Relative risks (RRs) were estimated using conditional logistic regression. Comparisons were also made with historical regional employment information available from the 1971 census.

RESULTS

There were many statistically significant positive associations for urothelial cancer risks and ever being employed in specified occupations (with or without statistical adjustment for smoking status in 1991). Smoking-adjusted RRs of > 2.0 were obtained for seven occupations; manufacture of fire lighters/ patent fuels (RR 4.30, 95% confidence interval 0.78-23.79), rodent extermination (3.71, 1.20-11.48), manufacture of dyestuffs (2.61, 0.98-7.00), leather work (2.51, 1.44-4.35), cable manufacturing industry (2.46, 1.20-5.04), textile printing and dyeing (2.32, 0.98-5.45), and sewage works (2.19, 1.16-4.11). Analyses of the occupations followed in 1971 (thus allowing for 20-year latency) indicated an elevated RR for workers in the plastics industry (5.22, 1.57-17.36).

CONCLUSIONS

The historical legacy of exposure to aromatic amines in the rubber, cable-making, dyestuffs and other industries remains. An important proportion of patients presenting with urothelial tumours are likely to have had occupational exposure to urothelial carcinogens. A review of occupational exposures in the contemporaneous plastic, textile and leather industries is warranted.

Lung cancer mortality in nickel/chromium platers, 1946-95

OBJECTIVES

To investigate mortality from lung cancer in nickel/chromium platers.

METHODS

The mortality experience of a cohort of 1762 chrome workers (812 men, 950 women) from a large electroplating and light engineering plant in the Midlands, United Kingdom, was investigated for the period 1946-95. All subjects were first employed in chrome work at the plant during the period 1946-75, and had at least six months employment in jobs associated with exposure to chromic acid mist (hexavalent chromium). Detailed job histories were abstracted from original company personnel records and individual cumulative durations of employment in three types of chrome work were derived as time dependent variables (chrome bath work, other chrome work, any chrome work). Two analytical approaches were used--indirect standardisation and Poisson regression.

RESULTS

Based on mortalities for the general population of England and Wales, male workers with some period of chrome bath work had higher lung cancer mortalities (observed deaths 40, expected deaths 25.41, standardised mortality ratio (SMR) 157, 95% confidence interval (95% CI) 113 to 214, p < 0.01) than did other male chrome workers (observed 9, expected 13.70, SMR 66, 95% CI 30 to 125). Similar findings were shown for female workers (chrome bath workers: observed 15, expected 8.57, SMR 175, 95% CI 98 to 289, p = 0.06; other chrome workers: observed 1, expected 4.37, SMR 23, 95% CI 1 to 127). Poisson regression was used to investigate risks of lung cancer relative to four categories of cumulative duration of chrome bath work and four categories of cumulative duration of other chrome work (none, < 1 y, 1-4 y, > or = 5 y). After adjusting for sex, age, calendar period, year of starting chrome work, period from first chrome work, and employment status (still employed v left employment), there was a significant positive trend (p < 0.05) between duration of chrome bath work and risks of mortality for lung cancer. Relative to a risk of unity for those chrome workers without any period of chrome bath work, risks were 2.83 (95% CI 1.47 to 5.45), 1.61 (95% CI 0.75 to 3.44), and 4.25 (95% CI 1.83 to 9.87) for the second, third, and fourth exposure categories, respectively. Duration of other chrome work was not a useful predictor of risks of lung cancer. Similar findings for both variables were obtained when adjustment was made for sex and age only. Similar findings for both variables were obtained relative to risk of chrome nasal ulceration.

CONCLUSIONS

The findings are consistent with the hypothesis that soluble hexavalent chromium compounds are potent human lung carcinogens.