Sunshine, rainfall, humidity and child pneumonia in the tropics: time-series analyses.

Few studies have formally examined the relationship between meteorological factors and the incidence of child pneumonia in the tropics, despite the fact that most child pneumonia deaths occur there. We examined the association between four meteorological exposures (rainy days, sunshine, relative humidity, temperature) and the incidence of clinical pneumonia in young children in the Philippines using three time-series methods: correlation of seasonal patterns, distributed lag regression, and case-crossover. Lack of sunshine was most strongly associated with pneumonia in both lagged regression [overall relative risk over the following 60 days for a 1-h increase in sunshine per day was 0·67 (95% confidence interval (CI) 0·51-0·87)] and case-crossover analysis [odds ratio for a 1-h increase in mean daily sunshine 8-14 days earlier was 0·95 (95% CI 0·91-1·00)]. This association is well known in temperate settings but has not been noted previously in the tropics. Further research to assess causality is needed.

A longitudinal case-control study of caries development from birth to 36 months.

BACKGROUND/AIMS: The aim of this longitudinal case-control study was to investigate variables associated with caries development from birth to 36 months. METHODS: Children (n = 1,017) who were followed up every 6 months from birth to 36 months were grouped into those that developed caries by age 30 and 36 months, respectively, and compared with children without caries. RESULTS: By 30 months (n = 608) there were 24 children (4%) who had caries and an additional 23 developed first caries at 36 months (n = 552), giving a total prevalence of 47 children with caries (9%) at 36 months. Children who showed caries by 30 months were more likely to be mutans streptococci (MS) colonised by 18 months (p = 0.001) compared to those who developed caries at 36 months, and showed the following variables: MS counts of >10(5) CFU/ml at 12 months (p = 0.005), missing enamel (p = 0.001), sugar in pacifier at 18 months (p = 0.02), child sleeping next to mother at 6, 18 and 24 months (p = 0.001 to p = 0.02), and exposure to household cigarette smoke at 24 months (p = 0.02). Caries at 36 months was associated with pregnancy problems (p = 0.024), mother having dental cavitations (p = 0.001) and MS presence at 36 months (adjusted odds ratio, AOR = 0.1, p = 0.01 for counts <10(5) CFU/ml). Caries at both 30 and 36 months was associated with MS presence at 18 months (AOR = 6.3, p = 0.005 and AOR = 4.9, p = 0.01). CONCLUSIONS: Children who developed caries by 30 months are colonised by MS at younger ages and with higher MS counts compared with children who develop caries at 36 months.

Cold and heat waves in the United States.

Extreme cold and heat waves, characterized by a number of cold or hot days in succession, place a strain on people's cardiovascular and respiratory systems. The increase in deaths due to these waves may be greater than that predicted by extreme temperatures alone. We examined cold and heat waves in 99 US cities for 14 years (1987-2000) and investigated how the risk of death depended on the temperature threshold used to define a wave, and a wave's timing, duration and intensity. We defined cold and heat waves using temperatures above and below cold and heat thresholds for two or more days. We tried five cold thresholds using the first to fifth percentiles of temperature, and five heat thresholds using the 95-99 percentiles. The extra wave effects were estimated using a two-stage model to ensure that their effects were estimated after removing the general effects of temperature. The increases in deaths associated with cold waves were generally small and not statistically significant, and there was even evidence of a decreased risk during the coldest waves. Heat waves generally increased the risk of death, particularly for the hottest heat threshold. Cold waves of a colder intensity or longer duration were not more dangerous. Cold waves earlier in the cool season were more dangerous, as were heat waves earlier in the warm season. In general there was no increased risk of death during cold waves above the known increased risk associated with cold temperatures. Cold or heat waves earlier in the cool or warm season may be more dangerous because of a build up in the susceptible pool or a lack of preparedness for extreme temperatures.

A longitudinal study comparing mutans streptococci and lactobacilli colonisation in dentate children aged 6 to 24 months.

This longitudinal study aimed to investigate variables associated with colonisation of mutans streptococci (MS) compared with lactobacilli (LB) colonisation in a cohort of children (n = 214) from the time of first tooth eruption at approximately 6 months until 24 months of age. Repeated plaque and salivary samples were collected from the same infants at 6, 12, 18 and 24 months and assayed for MS and LB using a microbiological culture kit. Children having both MS and LB increased from 4% at 6 months to 13% at 12 and 18 months to 20% at 24 months (p = 0.004). LB presence at 6 months was correlated with MS presence at 12, 18 and 24 months (r = 0.21 to r = 0.46, p = 0.02), while MS presence at 6 months correlated with LB presence at all other times (r = 0.19 to r = 0.31, p = 0.03). At 6 and 12 months, the key variables for MS colonisation included unrestored dental cavities in the mother (p = 0.03), mother not persisting with toothbrushing (p = 0.001) and bottle taken to bed at night (p = 0.033), while the only significant variable for LB colonisation was natural birth (p = 0.01). At 24 months, the significant variables for MS colonisation were condiments added to pacifier (p = 0.022) and child being uncooperative for toothbrushing (p = 0.025), while the significant variables for LB colonisation were pregnancy problems (p = 0.028) and child being uncooperative for toothbrushing (p = 0.013). The ages 6-12 months thus represent a time period when key variables may be controlled to reduce MS and LB colonisation.

Mutans streptococci and lactobacilli colonization in predentate children from the neonatal period to seven months of age.

BACKGROUND/AIMS: The aim of this study was to investigate the colonization of mutans streptococci (MS) and lactobacilli (LB) in predentate children from the neonatal period to 7 months. METHODS: A total of 957 mother-and-child pairs were recruited from birth and followed up at 7 months. The 283 children who did not have erupted teeth at the second visit were included in the study. Oral mucosal swabs were taken, and the presence of MS and LB was determined using a commercial microbiological culture kit. RESULTS: At mean ages of 34 days and 7 months, 9 and 11% of the infants, respectively, showed the presence of MS. In contrast, LB presence increased from 24 to 47% (p < 0.0001). MS presence in the neonatal period was associated with maternal MS counts of >10(5) CFU/ml (p = 0.05), while LB presence was associated with natural birth (p = 0.03) and maternal LB presence (p = 0.02). At 7 months, MS presence was associated with maternal MS counts (p = 0.02) and LB counts of >10(5) CFU/ml (p = 0.007). Additional predictors of MS presence at 7 months were a child's MS counts of >10(5) CFU/ml at the neonatal visit (p = 0.019) and nighttime bottle feeding (p = 0.024). LB presence at 7 months was associated with maternal LB (p < 0.001) and MS presence (p = 0.02). CONCLUSIONS: MS and LB can be detected by culture in the oral cavity as early as 34 days after birth. Their infection rates increase to 11 and 47%, respectively, by the time the children reach the end of the predentate stage of oral development.

A novel in vivo ovine model of transfusion-related acute lung injury (TRALI).

BACKGROUND AND OBJECTIVES: Even with the introduction of specific risk-reduction strategies, transfusion-related acute lung injury (TRALI) continues to be a leading cause of transfusion-related morbidity and mortality. Existing small animal models have not yet investigated TRALI resulting from the infusion of heat-treated supernatant from whole blood platelet concentrates. In this study, our objective was the development of a novel in vivo two-event model of TRALI in sheep. MATERIALS AND METHODS: Lipopolysaccharide (LPS; 15 µg/kg) as a first event, modelled clinical infection. Transfusion (estimated at 10% of total blood volume) of heat-treated pooled supernatant from date-of-expire human whole blood platelet concentrates (d5-PLT-S/N) was used as a second event. TRALI was defined by both hypoxaemia that developed either during the transfusion or within two hours of its completion and post-mortem histological evidence of pulmonary oedema. RESULTS: LPS infusion did not cause lung injury itself, but did result in decreased circulating levels of lymphocytes and neutrophils with evidence of the latter becoming sequestered in the lungs. Sheep that received LPS (first event) followed by d5-PLT-S/N (second event) displayed decreased pulmonary compliance, decreased end tidal CO(2) and increased arterial partial pressure of CO(2) relative to control sheep, and 80% of these sheep developed TRALI. CONCLUSIONS: This novel ovine two-event TRALI model presents a new tool for the investigation of TRALI pathogenesis. It represents the first description of an in vivo large animal model of TRALI and the first description of TRALI caused by transfusion with heat-treated pooled supernatant from human whole blood platelet concentrates.

Time-dependent analysis of extra length of stay and mortality due to ventilator-associated pneumonia in intensive-care units of ten limited-resources countries: findings of the International Nosocomial Infection Control Consortium (INICC).

Ventilator-associated pneumonias (VAPs) are a worldwide problem that significantly increases patient morbidity, mortality, and length of stay (LoS), and their effects should be estimated to account for the timing of infection. The purpose of the study was to estimate extra LoS and mortality in an intensive-care unit (ICU) due to a VAP in a cohort of 69,248 admissions followed for 283,069 days in ICUs from 10 countries. Data were arranged according to the multi-state format. Extra LoS and increased risk of death were estimated independently in each country, and their results were combined using a random-effects meta-analysis. VAP prolonged LoS by an average of 2·03 days (95% CI 1·52-2·54 days), and increased the risk of death by 14% (95% CI 2-27). The increased risk of death due to VAP was explained by confounding with patient morbidity.

Oxygen delivery through high-flow nasal cannulae increase end-expiratory lung volume and reduce respiratory rate in post-cardiac surgical patients.

BACKGROUND: High-flow nasal cannulae (HFNCs) create positive oropharyngeal airway pressure, but it is unclear how their use affects lung volume. Electrical impedance tomography allows the assessment of changes in lung volume by measuring changes in lung impedance. Primary objectives were to investigate the effects of HFNC on airway pressure (P(aw)) and end-expiratory lung volume (EELV) and to identify any correlation between the two. Secondary objectives were to investigate the effects of HFNC on respiratory rate, dyspnoea, tidal volume, and oxygenation; and the interaction between BMI and EELV. METHODS: Twenty patients prescribed HFNC post-cardiac surgery were investigated. Impedance measures, P(aw), ratio, respiratory rate, and modified Borg scores were recorded first on low-flow oxygen and then on HFNC. RESULTS: A strong and significant correlation existed between P(aw) and end-expiratory lung impedance (EELI) (r=0.7, P<0.001). Compared with low-flow oxygen, HFNC significantly increased EELI by 25.6% [95% confidence interval (CI) 24.3, 26.9] and P(aw) by 3.0 cm H(2)O (95% CI 2.4, 3.7). Respiratory rate reduced by 3.4 bpm (95% CI 1.7, 5.2) with HFNC use, tidal impedance variation increased by 10.5% (95% CI 6.1, 18.3), and ratio improved by 30.6 mm Hg (95% CI 17.9, 43.3). A trend towards HFNC improving subjective dyspnoea scoring (P=0.023) was found. Increases in EELI were significantly influenced by BMI, with larger increases associated with higher BMIs (P<0.001). CONCLUSIONS: This study suggests that HFNCs reduce respiratory rate and improve oxygenation by increasing both EELV and tidal volume and are most beneficial in patients with higher BMIs.

What measure of temperature is the best predictor of mortality?

Hot and cold temperatures significantly increase mortality rates around the world, but which measure of temperature is the best predictor of mortality is not known. We used mortality data from 107 US cities for the years 1987-2000 and examined the association between temperature and mortality using Poisson regression and modelled a non-linear temperature effect and a non-linear lag structure. We examined mean, minimum and maximum temperature with and without humidity, and apparent temperature and the Humidex. The best measure was defined as that with the minimum cross-validated residual. We found large differences in the best temperature measure between age groups, seasons and cities, and there was no one temperature measure that was superior to the others. The strong correlation between different measures of temperature means that, on average, they have the same predictive ability. The best temperature measure for new studies can be chosen based on practical concerns, such as choosing the measure with the least amount of missing data.

Using videotelephony to support paediatric oncology-related palliative care in the home: from abandoned RCT to acceptability study.

Videotelephony (real-time audio-visual communication) has been used successfully in adult palliative home care. This paper describes two attempts to complete an RCT (both of which were abandoned following difficulties with family recruitment), designed to investigate the use of videotelephony with families receiving palliative care from a tertiary paediatric oncology service in Brisbane, Australia. To investigate whether providing videotelephone-based support was acceptable to these families, a 12-month non-randomised acceptability trial was completed. Seventeen palliative care families were offered access to a videotelephone support service in addition to the 24 hours 'on-call' service already offered. A 92% participation rate in this study provided some reassurance that the use of videotelephones themselves was not a factor in poor RCT participation rates. The next phase of research is to investigate the integration of videotelephone-based support from the time of diagnosis, through outpatient care and support, and for palliative care rather than for palliative care in isolation. Trial registration ACTRN 12606000311550.

Seasonal temperature patterns and durations of acceptable temperature range in houses in Brisbane, Australia.

A paradigm shift to the use of indoor rather than outdoor temperature to estimate the exposure risk of low and high temperatures is vital for better prediction of temperature health effects and timely health warnings, and will also assist in understanding the influence of temperature on energy consumption and comfort. This study aimed to quantify the percentage of hours during the year that indoor temperature (living room) was in the extended comfort band (18-28 °C) of a subtropical climate, and identify the diurnal pattern of indoor temperatures in different seasons. Data used was collected in a previous study on the association between indoor and outdoor temperature. A k-shape cluster analysis resulted in two clusters of indoor temperature patterns for both weekdays and weekends. A bimodal pattern was identified during the cool season and a flat top pattern for the warm season, with many variations at weekends. These patterns can be attributed to the influence of cooling and heating processes depending on the season as well as occupancy, occupants' interference, and building materials. During the intermediate season, a sinusoidal pattern was observed for both weekdays and weekends because occupants likely relied on outdoor temperature conditions which were similar to those expected indoors without heating or cooling devices. The percentage of hours in which the indoor temperature of the houses ranged within the extended comfort band was 72-97% throughout the year, but for the coldest and hottest months it was 50-75%. These findings show that Brisbane residents are at possible risk of exposure to cold and hot temperatures due to the poor thermal performance of houses, and confirm that there is no standard indoor temperature pattern for all houses.

Strategies to reduce inappropriate laboratory blood test orders in intensive care are effective and safe: a before-and-after quality improvement study.

Unnecessary pathology tests performed in intensive care units (ICU) might lead to increased costs of care and potential patient harm due to unnecessary phlebotomy. We hypothesised that a multimodal intervention program could result in a safe and effective reduction in the pathology tests ordered in our ICU. We conducted a single-centre pre- and post-study using multimodal interventions to address commonly ordered routine tests. The study was performed during the same six month period (August to February) over three years: 2012 to 2013 (pre-intervention), 2013 to 2014 (intervention) and 2014 to 2015 (post-intervention). Interventions consisted of staff education, designing new pathology forms, consultant-led pathology test ordering and intensive monitoring for a six-month period. The results of the study showed that there was a net savings of over A$213,000 in the intervention period and A$175,000 in the post-intervention period compared to the pre-intervention period. There was a 28% reduction in the tests performed in the intervention period (P <0.0001 compared to pre-intervention period) and 26% in the post-intervention period (P <0.0001 compared to pre-intervention period). There were no ICU or hospital mortality differences between the groups. There were no significant haemoglobin differences between the groups. A multimodal intervention safely reduced pathology test ordering in the ICU, resulting in substantial cost savings.

Global tidal variations, regional distribution of ventilation, and the regional onset of filling determined by electrical impedance tomography: reproducibility.

The reproducibility of the regional distribution of ventilation and the timing of onset of regional filling as measured by electrical impedance tomography lacks evidence. This study investigated whether electrical impedance tomography measurements in healthy males were reproducible when electrodes were replaced between measurements. Part 1: Recordings of five volunteers lying supine were made using electrical impedance tomography and a pneumotachometer. Measurements were repeated at least three hours later. Skin marking ensured accurate replacement of electrodes. No stabilisation period was allowed. Part 2: Electrical impedance tomography recordings of ten volunteers; a 15 minute stabilisation period, extra skin markings, and time-averaging were incorporated to improve the reproducibility. Reproducibility was determined using the Bland-Altman method. To judge the transferability of the limits of agreement, a Pearson correlation was used for electrical impedance tomography tidal variation and tidal volume. Tidal variation was judged to be reproducible due to the significant correlation between tidal variation and tidal volume (r2 = 0.93). The ventilation distribution was not reproducible. A stabilisation period, extra skin markings and time-averaging did not improve the outcome. The timing of regional onset of filling was reproducible and could prove clinically valuable. The reproducibility of the tidal variation indicates that non-reproducibility of the ventilation distribution was probably a biological difference and not measurement error. Other causes of variability such as electrode placement variability or lack of stabilisation when accounted for did not improve the reproducibility of the ventilation distribution.

Funding for cerebral palsy research in Australia, 2000-2015: an observational study.

OBJECTIVES: To examine the funding for cerebral palsy (CP) research in Australia, as compared with the National Institutes of Health (NIH). DESIGN: Observational study. SETTING: For Australia, philanthropic funding from Cerebral Palsy Alliance Research Foundation (CPARF) (2005-2015) was compared with National Health and Medical Research Council (NHMRC, 2000-2015) and Australian Research Council (ARC, 2004-2015) and CPARF and NHMRC funding were compared with NIH funding (USA). PARTICIPANTS: Cerebral Palsy researchers funded by CPARF, NHMRC or NIH. RESULTS: Over 10 years, total CPARF philanthropic funding was $21.9 million, including people, infrastructure, strategic and project support. As competitive grants, CPARF funded $11.1 million, NHMRC funded $53.5 million and Australian Research Council funded $1.5 million. CPARF, NHMRC and NIH funding has increased in real terms, but only the NIH statistically significantly increased in real terms (mean annual increase US$4.9 million per year, 95% CI 3.6 to 6.2, p<0.001). The NHMRC budget allocated to CP research remained steady over time at 0.5%. A network analysis indicated the relatively small number of CP researchers in Australia is mostly connected through CPARF or NHMRC funding. CONCLUSIONS: Funding for CP research from the Australian government schemes has stabilised and CP researchers rely on philanthropic funding to fill this gap. In comparison, the NIH is funding a larger number of CP researchers and their funding pattern is consistently increasing.

A Longitudinal Observational Study of Developmental Defects of Enamel from Birth to 6 Years of Age.

Developmental defects of the enamel (DDE) commonly occur in the primary dentition. Although several cross-sectional studies have shown the association of DDE with caries, there is a paucity of longitudinal studies demonstrating that teeth with DDE are at greater risk of caries than are normal teeth. Therefore, the aim of the present study was to longitudinally track a total of 14,220 primary teeth in 725 children from a large birth cohort study, who were interviewed by telephone or home visits at 6-mo intervals. There were 74 children with at least 1 tooth with DDE. We compared teeth with and without DDE by calculating hazard ratios for caries using a Cox proportional hazards model and by plotting caries-free probabilities by child's age for DDE categories in a Kaplan-Meier plot. Our results show that teeth with DDE had a much higher risk for caries and developed caries earlier than did teeth without DDE. The hazard ratios (95% confidence intervals) for caries were 6.0 (2.4 to 14.6; P < 0.001) for pits, 5.5 (3.8 to 7.8; P < 0.001) for missing enamel, and 4.5 (1.8 to 11.3; P < 0.002) for hypoplasia occurring with yellow-brown opacities. Kaplan-Meier survival plots of caries-free probabilities by age, depending on DDE type, suggest that all types of enamel hypoplasia are associated with a statistically significant increased risk for caries. The study provides longitudinal evidence that DDE are a strong determinant for caries in the primary dentition (ACTRN No. 012606000356561). Knowledge Transfer Statement: The study provides longitudinal evidence that developmental defects of enamel of the primary dentition are strongly associated with increased risk of early childhood caries.

The time taken for the regional distribution of ventilation to stabilise: an investigation using electrical impedance tomography.

Electrical impedance tomography is a novel technology capable of quantifying ventilation distribution in the lung in real time during various therapeutic manoeuvres. The technique requires changes to the patient's position to place the electrical impedance tomography electrodes circumferentially around the thorax. The impact of these position changes on the time taken to stabilise the regional distribution of ventilation determined by electrical impedance tomography is unknown. This study aimed to determine the time taken for the regional distribution of ventilation determined by electrical impedance tomography to stabilise after changing position. Eight healthy, male volunteers were connected to electrical impedance tomography and a pneumotachometer. After 30 minutes stabilisation supine, participants were moved into 60 degrees Fowler's position and then returned to supine. Thirty minutes was spent in each position. Concurrent readings of ventilation distribution and tidal volumes were taken every five minutes. A mixed regression model with a random intercept was used to compare the positions and changes over time. The anterior-posterior distribution stabilised after ten minutes in Fowler's position and ten minutes after returning to supine. Left-right stabilisation was achieved after 15 minutes in Fowler's position and supine. A minimum of 15 minutes of stabilisation should be allowed for spontaneously breathing individuals when assessing ventilation distribution. This time allows stabilisation to occur in the anterior-posterior direction as well as the left-right direction.

Availability of services to treat patients with acute low back pain.

Guidelines for the management of acute low back pain were published in 1994. This national survey, conducted soon after, showed that the availability of services for general practitioners (GPs) to treat acute back pain fell short of the guideline recommendations. A repeat survey will be performed to measure the impact of guideline publication and dissemination.

Evaluation of two time-specific back pain outcome measures.

STUDY DESIGN: Postal questionnaire to individuals with back pain. OBJECTIVE: To assess the acceptability, validity, and reliability of two existing back pain outcome measures, the Roland-Morris Questionnaire and the Von Korff scales, modified to measure the preceding 4 weeks. SUMMARY OF BACKGROUND DATA: The ideal outcome measure for studies of low back pain and disability remains elusive. Most existing measures assess current pain and disability. Measuring these factors over a preceding 4-week period may be more appropriate. METHODS: Individuals with back pain identified in a community survey were asked to complete the modified questionnaires. Validity was assessed by comparison with the Medical Outcome Study Short Form 36 and two general comparator questions on self-reported pain and disability. Repeatability was assessed using retest questionnaires. RESULTS: Completed questionnaires were returned by 95 individuals with chronic back pain. The modified Roland-Morris Questionnaire and Von Korff pain and Von Korff disability scales were completed satisfactorily by 83 (87%), 89 (94%), and 87 (92%) participants, respectively. Mean scores of the modified measures changed significantly and in a predictable manner with increasing ratings of pain and disability. They also correlated with aspects of the Medical Outcome Study Short Form 36 questionnaire. Retest data suggest that these measures are repeatable. The modified Roland-Morris Questionnaire provided adequate analyzable data only if missing values were imputed, and it explained less of the variance in the comparator questions than the modified Von Korff scales. CONCLUSIONS: The modified Von Korff scales were completed easily and appear to be valid and repeatable in this format.

Interventions to control nosocomial infections: study designs and statistical issues.

There is a wide range of potential study designs for intervention studies to decrease nosocomial infections in hospitals. The analysis is complex due to competing events, clustering, multiple timescales and time-dependent period and intervention variables. This review considers the popular pre-post quasi-experimental design and compares it with randomized designs. Randomization can be done in several ways: randomization of the cluster [intensive care unit (ICU) or hospital] in a parallel design; randomization of the sequence in a cross-over design; and randomization of the time of intervention in a stepped-wedge design. We introduce each design in the context of nosocomial infections and discuss the designs with respect to the following key points: bias, control for non-intervention factors, and generalizability. Statistical issues are discussed. A pre-post-intervention design is often the only choice that will be informative for a retrospective analysis of an outbreak setting. It can be seen as a pilot study with further, more rigorous designs needed to establish causality. To yield internally valid results, randomization is needed. Generally, the first choice in terms of the internal validity should be a parallel cluster randomized trial. However, generalizability might be stronger in a stepped-wedge design because a wider range of ICU clinicians may be convinced to participate, especially if there are pilot studies with promising results. For analysis, the use of extended competing risk models is recommended.