Strategies to improve survival outcomes of out-of-hospital cardiac arrest (OHCA) given a fixed budget: A simulation study.

BACKGROUND: Our study aimed to identify a strategy that maximizes survival upon hospital discharge or 30-days post out-of-hospital cardiac arrest (OHCA) in Singapore for fixed investments of S$1, S$5, or S$10 million. Four strategies were compared: (1) no additional investment; (2) reducing response time via leasing of more ambulances; (3) increasing number of people trained in cardiopulmonary resuscitation (CPR); and (4) automated external defibrillators (AED). METHODS: We estimated the effect of ambulance response time, bystander CPR and AED on survival based on Singapore's 2010-2015 OHCA registry data. We simulated the changes in ambulance response times and likelihood of (1) CPR and (2) AED usage as a function of their increased availability, which was then combined with the effect of each factor to determine the increase in survival for each strategy. RESULTS: Survival given no additional investment was 4.03% (95% CI: 3.96%, 4.10%). The investments in ambulances, CPR training and AEDs for a given budget of S$1M changed survival to 4.03% (95% CI: 3.96%, 4.10%), 4.04% (95% CI: 3.98%, 4.11%), and 4.44% (95% CI: 4.35%, 4.54%), respectively. This generated 0, 2 and 102 additional life years saved respectively. Given a budget of S$5M or S$10M, 509 or 886 additional life years could be saved, by investing in an additional 10,000 or 20,000 AEDs respectively. The strategies reached a saturation effect whereby improvement in survival was marginal when the budget was increased to ≥S$5M for investment in ambulances and CPR training. CONCLUSIONS: Investing in AEDs had the most gain in survival.

Entamoeba invadens myositis in a common water monitor lizard (Varanus salvator).

Amoebiasis is one of the most common protozoal diseases of reptiles, but amoebic myositis has not been reported in any animal species. An 11-year-old, male common water monitor lizard (Varanus salvator) was found dead with several subacute ulcerated skin wounds. Gross examination revealed multiple discrete to coalescing, white-yellow to gray, caseous foci scattered in the skeletal muscles and liver. The mucosa of small intestine was thickened, red, and contained many variably sized, dark red ulcers, with depressed and hemorrhagic centers. Histopathologic examination revealed severe necrotizing and granulomatous myositis, hepatitis, and enteritis accompanied by large numbers of intralesional, 10-20-microm diameter, periodic acid-Schiff-positive, amoeboid protozoa. Gene sequence analysis of a 136-bp region of the 18S ribosomal RNA amplified by polymerase chain reaction revealed 98-100% similarity with Entamoeba invadens. Aside from intestinal and hepatic involvement, no other internal organs were affected. The muscular infection by E. invadens likely resulted from a combination of direct invasion of trophozoites via skin wounds and hematogenous spread.

Validity of the running repeated sprint ability test among playing positions and level of competitiveness in trained soccer players.

The purpose of this study was to examine the construct validity of the running repeated sprint ability (rRSA) test to discriminate performances between: i) various playing positions (Study 1), and ii) teams of different level of competitiveness (Study 2), in trained soccer players. Study 1 comprised clubs' players participating in the top local professional league. Study 2 comprised professional and semiprofessional players from the National Under-23 and Youth squads respectively, and amateur-level players from a University team. The rRSA test protocol consisted of either 6 or 8 repetitions of 20-m all-out sprints, interspersed with a 20-s active recovery period. There were significant differences in the rRSA performance between goalkeepers and outfield-positions (p < 0.01). Forwards had significantly better rRSA performance compared to defenders and midfielders (F ratio = 4.147, p = 0.02). Performance in the rRSA was superior in teams with relatively higher competitiveness (F ratio = 3.973, p = 0.02). The rRSA is a specific physical or fitness attribute of an outfield-position player, and may be of greater importance to the forwards' position. Performance in the rRSA also seems to be associated with a higher level of competitiveness and/or adaptation to resistance training. These data support the construct validity of the rRSA test in trained soccer players.

Relationship between measured maximal oxygen uptake and aerobic endurance performance with running repeated sprint ability in young elite soccer players.

AIM: The aim of the study was to determine the relationships between maximal oxygen uptake (VO(2max)) in a maximal treadmill run and the aerobic endurance performance in the 20-m multistage shuttle run (MST) test, with the performance indices obtained in the running repeated sprint ability (rRSA) test, in elite youth soccer players. METHODS: Thirty-seven adolescent male outfield players performed on separate days and in random order the treadmill run test and the MST, to obtain their measured VO(2max) and aerobic endurance performance (via the number of completed shuttles in the MST), respectively. Players also completed the rRSA test of 6x20-m all-out sprints, interspersed with 20 s of active recovery. RESULTS: There was a significant moderate correlation between measured VO(2max) (in L . min(-1) and mL . kg(-1) . min(-1)) and MST results (r=0.43 and 0.54, P<0.05, respectively). There was no significant correlation between measured VO(2max) and aerobic endurance performance with any of the performance indices in the rRSA test (all P>0.05). CONCLUSION: The moderate association between the measured VO(2max) and MST suggests that both tests were plausibly measuring different aspects of a player's aerobic fitness. The lack of association between measured VO(2max) and aerobic endurance performance in the MST with performance in the rRSA suggests that aerobic fitness per se is poorly associated with performance in the rRSA in elite youth soccer players.

Measured maximal oxygen uptake in a multi-stage shuttle test and treadmill-run test in trained athletes.

AIM: The aims of the study were: i) to compare the measured maximal oxygen uptake (MVO2max) during the 20 m multi-stage shuttle test (MST) with MVO2max during an incremental treadmill-run test (TRT), and ii) to establish the reliability of MVO2max during MST, in trained athletes. EXPERIMENTAL DESIGN: 8 well-trained endurance-athletes (END) and 8 athletes involved in team games (GAM) performed the MST twice (i.e. MST1 and MST2) and the TRT once, in 3 separate sessions. MEASURES: MVO2maxx attained in the MST and TRT was measured using a portable respiratory analyser (model K4 RQ, Cosmed). RESULTS: MVO2max attained in the MST and TRT were significantly different for the END athletes (4.1+/-0.28 vs 4.45+/-0.31 Lxmin-1, P<0.05) but not for GAM athletes (4.01+/-0.51 vs 4.1+/-0.59 Lxmin-1, P>0.05). The 95% limits of agreement for MVO2max in the MST in Lxmin-1 were -0.67 to 0.27. MVO2max in MST1 and MST2 were not significantly different for END athletes (4.18+/-0.39 vs 4.1+/-0.28 Lxmin-1, P>0.05) and GAM athletes (4.01+/-0.55 vs 4.01+/-0.51 Lxmin-1, P>0.05). Reliability indicators for MVO2max in Lxmin-1 for MST test-retest were: typical error (TE)=0.14, coefficient of variation (CV)=3.5 and intra-class correlation (ICC)=0.90. CONCLUSION: MVO2max in the MST was lower than that measured in the TRT for the END athletes but not for the GAM athletes. Sport-specificity was an important consideration, especially when testing END athletes for VO2max. MVO2max in the MST showed acceptable levels of reproducibility.

Short term power output in relation to growth and maturation.

OBJECTIVE: To examine short term power output during growth and maturation using a multilevel modelling approach. METHODS: Body mass, stature, and triceps and subscapular skinfold thicknesses of boys and girls, aged 12.2 (0.4) years (mean (SD)) at the onset of the study, were measured at age 12, 13, and 17 years. Sexual maturation, classified according to Tanner's stage of pubic hair development, was assessed on the first two occasions and assumed to be stage 5 at 17 years. Peak power (PP) and mean power (MP) were assessed on each occasion using the Wingate anaerobic test. RESULTS: Initial models, founded on 417 determinations of short term power output, identified body mass, stature, and age as significant explanatory variables of both PP and MP. The values for girls were significantly lower than those for boys, and a significant age by sex interaction described a progressive divergence in the MP of boys and girls. The introduction of sum of two skinfold thicknesses produced a model with an improvement in fit as indicated by a significant change in log likelihood. The stature term was negated and the body mass term increased. The age and sex terms were reduced but remained significant. The age by sex interaction term remained a significant explanatory variable for MP. Maturity effects were non-significant additional explanatory variables in all models of power output. CONCLUSION: The values of PP and MP for boys are higher than those for girls, and, for MP, sex differences increase with age. Body mass and skinfold thicknesses are significant influences on both PP and MP, but age exerts a positive but non-linear effect on power output independent of body size and fatness.

Changes in short-term power output in 10- to 12-year-olds.

In this study, we used multi-level regression modelling to assess the influence of age, sex, body size, skinfold thicknesses, maturity, thigh muscle volume and isokinetic leg strength on the development of load- and inertia-adjusted peak (1 s) and mean power (30 s) determined using the Wingate anaerobic test. Fifteen males and 19 females were measured twice, first aged 10.0 +/- 0.3 years and then aged 11.8 +/- 0.3 years. Initial models identified body mass and height as significant explanatory variables (P < 0.05) for peak power and mean power, with an additional age effect for the former. No significant differences between the sexes or maturity effects were observed for either peak or mean power (P > 0.05). The introduction of sum of skinfolds improved the fit of the model and rendered the height term non-significant for both peak and mean power (P> 0.05). An age effect became apparent for mean power. When isokinetic leg strength and thigh muscle volume were entered into the model, the latter exerted a significant effect on both peak and mean power (P< 0.05), whereas isokinetic leg strength was not a significant explanatory variable for either (P> 0.05). In conclusion, thigh muscle volume exerts a positive influence on young people's short-term power output, which is additional to the effects of body mass, sum of skinfolds and age.