Rose Baker

Effects of oxandrolone on outcome measures in the severely burned: a multicenter prospective randomized double-blind trial.

Severe burns induce pathophysiologic problems, among them catabolism of lean mass, leading to protracted hospitalization and prolonged recovery. Oxandrolone is an anabolic agent shown to decrease lean mass catabolism and improve wound healing in the severely burned patients. We enrolled 81 adult subjects with burns 20% to 60% TBSA in a multicenter trial testing the effects of oxandrolone on length of hospital stay. Subjects were randomized between oxandrolone 10 mg every 12 hours or placebo. The study was stopped halfway through projected enrollment because of a significant difference between groups found on planned interim analysis. We found that length of stay was shorter in the oxandrolone group (31.6 ± 3.1 days) than placebo (43.3 ± 5.3 days; P < .05). This difference strengthened when deaths were excluded and hospital stay was indexed to burn size (1.24 ± 0.15 days/% TBSA burned vs 0.87 ± 0.05 days/% TBSA burned, P < .05). We conclude that treatment using oxandrolone should be considered for use in the severely burned while hepatic transaminases are monitored.

Effective time to satisfactory intubation conditions after administration of rocuronium in adults Comparison of propofol and thiopentone for rapid sequence induction of anaesthesia

We determined the effective time to satisfactory intubation conditions after the administration of rocuronium 0.6 mgkg−1 to 120 unpremedicated adult patients anaesthetised with propofol 2.5 mgkg−1 or thiopentone 5 mgkg−1. Intubation conditions were assessed in 10 subgroups of 12 patients at 30, 40, 50, 60 and 70 s. The effective times to satisfactory intubation conditions in 50 and 90% of patients were obtained by the method of maximum likelihood after log time–probit response transformations. Intubation conditions after induction of anaesthesia with propofol were satisfactory in 5/12 patients at 30 s, 7/12 at 40 s, 10/12 at 50 s, 11/12 at 60 s and 11/12 at 70 s compared with 1/12 patients at 30 s, 2/12 at 40 s, 5/12 at 50 s, 7/12 at 60 s and 8/12 at 70 s after induction with thiopentone. The effective times to satisfactory intubation conditions in 50% and 90% (95% confidence intervals) of patients after rocuronium 0.6 mgkg−1 were 34 (26–40) s and 61 (50–81) s in patients given propofol compared with 57 (48–69) s and 101 (79–167) s in patients given thiopentone. We conclude that rocuronium 0.6 mgkg−1 may be a suitable alternative to suxamethonium during rapid sequence induction of anaesthesia with propofol in situations where suxamethonium is contraindicated.

Review of delay-time OR modelling of engineering aspects of maintenance

This review paper discusses the development of delay-time analysis as a means of modelling engineering aspects of maintenance problems. The main concern of the paper is with the philosophy, underlying principles, assumptions and experiences in practice, with references being given to more detailed accounts elsewhere. The current state of knowledge and research in the area will be outlined, and future trends in modelling applications and research predicted. A question that will be addressed is whether the application of delay-time analysis could and should be de-skilled to the extent that it could be effectively utilised by engineers in the absence of a modelling analyst.

Trypanosoma congolense : the distribution of enzymic variants in East and West Africa

A total of 114 stocks of Trypanosoma congolense originating from Kenya, Uganda, Tanzania, Zambia and Sudan, but including, for comparison, stocks from The Gambia, Liberia, Ivory Coast, Nigeria and Cameroun, were compared by isoenzyme electrophoresis for 6 enzymes. The zymodemes were grouped, both from a dendrogram and using a cladistic method, after calculating the dissimilarity, or distance, between profiles. Previous observations are broadly confirmed, the zymodemes clustering separately according to geographical origin and ecological zone. Thus, one group was composed almost entirely of East African stocks, and another of stocks from both East and West Africa, although each group was of savanna origin. A third group was composed of stocks from the humid, rain-forest zones of West Africa, and was particularly characterized by isoenzyme variants of superoxide dismutase and glucose-phosphate isomerase. Two stocks from the Kenyan coast formed a markedly separate group, which may be taxonomically distinct.

Burn wound healing time assessed by laser Doppler imaging (LDI). Part 1: Derivation of a dedicated colour code for image interpretation

INTRODUCTION Laser Doppler imaging produces a colour-coded image of dermal blood flow, which can be used to quantify the inflammatory response in a burn. The original colour palette had arbitrary boundaries, which inexperienced clinicians found difficult to interpret. The aim of this study was to define clinically useful boundaries that would assist in the prediction of burn healing potential. METHOD We conducted a prospective, multi-centre study of burns in adults and children. LDI scans were performed between 48 h and 5 days after injury. The burns were assessed clinically and photographed on day of scan, day 14 and day 21 post-injury. Areas healed at day 14, healed between day 14 and 21 and unhealed at day 21 were identified on the LDI scan. The flow values for the pixels in these regions were analysed to calculate boundaries between the three healing categories. RESULTS We recruited 137 patients (ages 1-88 years, 65% male); 392 LDI scans contained 433 different burn sites; 109 regions of interest were studied. Analysis allowed us to define ranges for the three healing categories: HP14 colour coded red, >600 PU; HP14-21, yellow, 260-440 PU; HP>21, blue, <200 PU; separated by two overlap regions pink, 440-600 PU and green, 200-260 PU. Blue was subdivided to show the very high association between LDI<140 PU and non-healing at day 21. CONCLUSION We have devised a new colour palette for LDI burn imaging based on healing times of a series of burns. Validation of this palette is described separately, in Part 2.

A comparison of acceleromyography and mechanomyography for determination of the dose–response curve of rocuronium in children

In order to compare an acceleromyograph (TOF‐GuardTM) with a mechanomyograph (Grass FT03), the dose–response relationship of rocuronium was simultaneously determined in both arms of 15 children aged 3–11 years during anaesthesia with thiopentone, alfentanil and nitrous oxide. Three subgroups of five children received rocuronium 120, 180 or 240 μg.kg−1 randomly. The effective doses to produce 50% and 95% depression of the first twitch of the train‐of‐four determined by acceleromyography were 206 and 337 μg.kg−1, respectively, while these values determined by mechanomyography were 151 and 331 μg.kg−1, respectively. The dose–response curve obtained by acceleromyography was steeper and shifted to the right compared with that obtained by mechanomyography (p < 0.0001). The difference between the effective dose producing 50% twitch depression determined by the two devices was highly significant (p < 0.0001). In 13 out of 15 children, the acceleromyograph control train‐of‐four ratio was significantly greater than unity. Although there was a good correlation (r = 0.85) between simultaneous pairs of measurements of neuromuscular block, the acceleromyograph exhibited a bias of −25% relative to the mechanomyograph with wide limits of agreement (−62 to +12%). We conclude that acceleromyographic and mechanomyographic measurements should not be used interchangeably when determining the potency of muscle relaxants.

Use of a mathematical model to evaluate breast cancer screening policy

A model of breast cancer screening was developed, in which the processes of tumour origination and growth, detection of tumours at screening, presentation of women with cancers to their GP, and of survival after diagnosis were modelled parametrically. The model was fitted to data from the North‐West of the UK, for 413 women who screened positive, and for 761 women who developed interval cancers. Model validation comprised verification that the final model fitted the data adequately, together with the comparison of model predictions with findings by other workers.The mathematical model was used to assess different screening policies, and to ask “what if” questions. Taking the cost of breast cancer to be the sum of the cost of screening and the cost of PYLL (person years of life lost due to cancer), the optimal screening policy was calculated. The costs of the current policy and of other possible screening policies were found, together with their effects on life lost and on mortality. The tentative conclusion was that if monies can be found to extend the screening programme, for example to carry out one more screen per woman, most benefit would be obtained by reducing the start age of screening by 3 years.

Endoscopic balloon dilatation of Crohn's disease strictures: results from a large United kingdom series.

Introduction:Stricturing is a common complication of Crohns disease. Endoscopic balloon dilatation (EBD) offers a valuable alternative to surgical intervention, but there are limited data on factors influencing its safety and efficacy. Methods:A multicenter retrospective audit across 4 U.K. teaching hospitals was performed on the use of EBD for Crohns strictures between 1998 and 2011. Demographics, smoking status, medications, C-reactive protein, endoscopic findings, and subsequent surgery at follow-up were recorded. Success of EBD was defined as symptomatic improvement without the need for surgery at follow-up. Results:Seventy-nine patients (47 women; median age, 48 yr) were identified for this study. Forty-eight (61%) patients had ileocolonic anastomotic strictures, whereas the rest had de novo strictures. In total, 191 EBDs (range, 1–11; median 2) were carried out on 93 strictures (range, 1–5; median 1) over a median duration of 12 months (range, 1–84). There were no serious adverse events. Success at index EBD was 34%, with a further 43% achieving long-term benefit from additional EBDs. Eighteen (23%) patients required surgery. Time to surgery after the first EDB was 2.6 to 71.1 months (median, 12.8 mo). Longer Crohns disease duration (P = 0.03) and high C-reactive protein (P = 0.008) were associated with an increased need for subsequent surgery. Conclusions:EBD was safe and effective in achieving long-term symptom improvement and avoidance of surgery in most patients. Prospective controlled trials are needed to evaluate the effect of other factors, including Crohns disease phenotype, and the role of concomitant medication to identify those best suited to EBD.

Data-Based Modeling of the Failure Rate of Repairable Equipment

A databaseof failures of many types of medical equipment was analysed,to study the dependence of failure rate on equipment age andon time since repair. The intention was to use this large datasetto assess the validity of some widely-used models of failurerate, such as the power-law and loglinear Poisson processes,and so to recommend simple and adequate models to those practitionershaving little data to discriminate between rival models. Theaim is also to illustrate a methodology for computing policycosts from failure databases. The power-law process model wasfound to fit slightly better overall than did the loglinear andlinear processes. Some related models were created to fit anobserved peaking of failure rate. The data showed a decreasinghazard of (first) failure after repair for some equipment types.This can be due to imperfect or hazardous repair, and also todiffering failure rates among a population of machines. Two simplemodels of imperfect repair were used to fit the data, and anEmpirical Bayes method was used to fit a model of variable failurerate between machines. Neglect of such variation can lead toan over-estimate of the hazardousness of repair.

The possible role of Rickettsia-like organisms in trypanosomiasis epidemiology

A simple model of human and animal trypanosomiasis is proposed in which the Ross equation for disease transmission is supplemented by a differential equation describing the inheritance of susceptibility in the vector. The model predicts an equilibrium state of balanced polymorphism for the fraction, theta, of susceptible tsetse and the occurrence of periodic epidemics at roughly the observed intervals. A loss of infectivity to tsetse of mechanically transmitted strains of trypanosome would seem to be a good evolutionary strategy for the trypanosome. The main implication for disease control is that measures initially reducing trypanosomiasis incidence could trigger off subsequent epidemics. Since theta leads incidence, monitoring theta could give several years advance warning of major epidemics. The model leads to oscillations in prevalence which are only lightly damped. Other mechanisms producing periodic epidemics would interact with this mechanism, and result in only one sequence of recurrent epidemics. With typical random variation of tsetse numbers about the seasonal norm the model shows the behaviour of a narrow-band system excited by broad-band noise, i.e. predicted trypanosomiasis incidence exhibits an undamped series of oscillations of variable amplitude and phase, similar to what is actually observed.