Inter-annual variability of land surface fluxes across vineyards: the role of climate, phenology, and irrigation management.

Irrigation and other agricultural management practices play a key role in land surface fluxes and their interactions with atmospheric processes. California's Central Valley agricultural productivity is strongly linked to water availability associated with conveyance infrastructure and groundwater, but greater scrutiny over agricultural water use requires better practices particularly during extended and severe drought conditions. The future of irrigated agriculture in California is expected to be characterized neither by perpetual scarcity nor by widespread abundance. Thus, further advancing irrigation technologies and improving management practices will be key for California's agriculture sustainability. In this study, we present micrometeorological observations from the Grape Remote Sensing Atmospheric Profile and Evapotranspiration eXperiment (GRAPEX) project. Daily, seasonal, and inter-seasonal surface flux patterns and relationships across five vineyards over three distinct California wine production regions were investigated. Vineyard actual evapotranspiration showed significant differences at the sub-daily and daily scale when comparisons across wine production regions and varieties were performed. Water use in vineyards in the Central Valley was about 70% greater in comparison to the vineyards at the North Coast area due to canopy size, atmospheric demand, and irrigation inputs. Inter-annual variability of surface fluxes was also significant, even though, overall weather conditions (i.e., air temperature, vapor pressure deficit, wind speed, and solar radiation) were not significantly different. Thus, not only irrigation but also other management practices played a key role in seasonal water use, and given these differences, we conclude that further advancing ground-based techniques to quantify crop water use at an operational scale will be key to facing California's agriculture present and future water challenges. Supplementary Information: The online version contains supplementary material available at 10.1007/s00271-022-00784-0.

Introducing mobile fracture prevention services with DXA in Northern Scotland: a comparative study of three rural communities.

Mobile fracture prevention services, with DXA, significantly improved access to care for those at high risk of fracture living in rural areas. Introduction of mobile services facilitated access to fracture liaison services and development of integrated of care pathways across community- and secondary-based care. INTRODUCTION: The ageing population is growing faster in rural areas, yet most fracture prevention services are located in urban areas. As part of a wider study, evaluating the introduction of mobile fracture prevention services, we focus on whether mobile services improve access to care for those at highest risk of fracture. METHODS: Services outcomes were assessed against the Royal Osteoporosis Society clinical standards for fracture liaison services. This included standardised, age-specific referral rates, FRAX 10-year probability of major osteoporotic and hip fracture of referrals, pre- and post-introduction of the mobile service across two island and one rural mainland sites. This was compared with referrals from a similar rural mainland region with local access to a comprehensive service. RESULTS: Greatest impact occurred in areas with most limited service provision at baseline. Mean age of patients referred increased from 59 to 68 years (CI 6.8-10.1, p < 0.001). Referral rates increased from 2.8 to 5.4 per 1000 population between 2011 and 2018, with a 5-fold rise in those ≥ 75 years (0.4 to 2.0 per 1000). Mean FRAX 10-year risk of major osteoporotic fracture increased from 12.7 to 17.7% (CI 3.2-5.7, p < 0.001). Mean hip fracture risk probability increased from 3.0 to 5.7% (CI 2.0-3.4, p < 0.001). However, referral rates from the mobile sites remained lower than the comparator site. CONCLUSIONS: Mobile fracture prevention services, including DXA, greatly improved uptake amongst high-risk individuals. Mobile services facilitated development of integrated of care pathways, including fracture liaison services, across community- and secondary-based care.

Help or hindrance: young people's experiences of predictive testing for Huntington's disease.

A growing number of young people (YP) are requesting predictive testing (PT) for Huntington's disease (HD), yet there is little research in this area. The aim of this study was to explore YP's experiences of PT for HD, the impact of their result and any gaps in information or support. In-depth interviews were conducted with YP who sought PT for HD from nationally funded Genetics Services. Participants were recruited through the Grampian Genetics Service or Scottish Huntington's Association. Twelve female participants aged 17-26 years were recruited (seven below 20 years). Pre- and post-test interviews were conducted where possible. A qualitative thematic analysis suggests three main testing experiences, regardless of test result. Testing may be: (i) a journey of empowerment, (ii) an ambivalent process or (iii) a poor experience. In pre-test counselling, gaps in emotional support were highlighted. The post-test period was particularly difficult if there were unanticipated changes in family dynamics or an individual's result contradicted what they expected 'deep down'. YP's experiences of PT for HD are generally similar to those of adults, but testing may help or interfere with key issues related to this age and stage. Implications for clinical practice are outlined.

Estimation of Contaminant Loads from the Sacramento-San Joaquin River Delta to San Francisco Bay.

Contaminant concentrations from the Sacramento-San Joaquin River watershed were determined in water samples mainly during flood flows in an ongoing effort to describe contaminant loads entering San Francisco Bay, CA, USA. Calculated PCB and total mercury loads during the 6-year observation period ranged between 3.9 and 19 kg/yr and 61 and 410 kg/yr, respectively. Long-term average PCB loads were estimated at 7.7 kg/yr and total mercury loads were estimated at 200 kg/yr. Also monitored were PAHs, PBDEs (two years of data), and dioxins/furans (one year of data) with average loads of 392, 11, and 0.15/0.014 (OCDD/OCDF) kg/yr, respectively. Organochlorine pesticide loads were estimated at 9.9 kg/yr (DDT), 1.6 kg/yr (chlordane), and 2.2 kg/yr (dieldrin). Selenium loads were estimated at 16 300 kg/yr. With the exception of selenium, all average contaminant loads described in the present study were close to or below regulatory load allocations established for North San Francisco Bay.

Post-processed data and graphical tools for a CONUS-wide eddy flux evapotranspiration dataset.

Large sample datasets of in situ evapotranspiration (ET) measurements with well documented data provenance and quality assurance are critical for water management and many fields of earth science research. We present a post-processed ET oriented dataset at daily and monthly timesteps, from 161 stations, including 148 eddy covariance flux towers, that were chosen based on their data quality from nearly 350 stations across the contiguous United States. In addition to ET, the data includes energy and heat fluxes, meteorological measurements, and reference ET downloaded from gridMET for each flux station. Data processing techniques were conducted in a reproducible manner using open-source software. Most data initially came from the public AmeriFlux network, however, several different networks (e.g., the USDA-Agricultural Research Service) and university partners provided data that was not yet public. Initial half-hourly energy balance data were gap-filled and aggregated to daily frequency, and turbulent fluxes were corrected for energy balance closure error using the FLUXNET2015/ONEFlux energy balance ratio approach. Metadata, diagnostics of energy balance, and interactive graphs of time series data are included for each station. Although the dataset was developed primarily to benchmark satellite-based remote sensing ET models of the OpenET initiative, there are many other potential uses, such as validation for a range of regional hydrologic and atmospheric models.

Reducing methylmercury accumulation in the food webs of San Francisco Bay and its local watersheds.

San Francisco Bay (California, USA) and its local watersheds present an interesting case study in estuarine mercury (Hg) contamination. This review focuses on the most promising avenues for attempting to reduce methylmercury (MeHg) contamination in Bay Area aquatic food webs and identifying the scientific information that is most urgently needed to support these efforts. Concern for human exposure to MeHg in the region has led to advisories for consumption of sport fish. Striped bass from the Bay have the highest average Hg concentration measured for this species in USA estuaries, and this degree of contamination has been constant for the past 40 years. Similarly, largemouth bass in some Bay Area reservoirs have some of the highest Hg concentrations observed in the entire US. Bay Area wildlife, particularly birds, face potential impacts to reproduction based on Hg concentrations in the tissues of several Bay species. Source control of Hg is one of the primary possible approaches for reducing MeHg accumulation in Bay Area aquatic food webs. Recent findings (particularly Hg isotope measurements) indicate that the decades-long residence time of particle-associated Hg in the Bay is sufficient to allow significant conversion of even the insoluble forms of Hg into MeHg. Past inputs have been thoroughly mixed throughout this shallow and dynamic estuary. The large pool of Hg already present in the ecosystem dominates the fraction converted to MeHg and accumulating in the food web. Consequently, decreasing external Hg inputs can be expected to reduce MeHg in the food web, but it will likely take many decades to centuries before those reductions are achieved. Extensive efforts to reduce loads from the largest Hg mining source (the historic New Almaden mining district) are underway. Hg is spread widely across the urban landscape, but there are a number of key sources, source areas, and pathways that provide opportunities to capture larger quantities of Hg and reduce loads from urban runoff. Atmospheric deposition is a lower priority for source control in the Bay Area due to a combination of a lack of major local sources. Internal net production of MeHg is the dominant source of MeHg that enters the food web. Controlling internal net production is the second primary management approach, and has the potential to reduce food web MeHg in some habitats more effectively and within a much shorter time-frame. Controlling net MeHg production and accumulation in the food web of upstream reservoirs and ponds is very promising due to the many features of these ecosystems that can be manipulated. The most feasible control options in tidal marshes relate to the design of flow patterns and subhabitats in restoration projects. Options for controlling MeHg production in open Bay habitat are limited due primarily to the highly dispersed distribution of Hg throughout the ecosystem. Other changes in these habitats may also have a large influence on food web MeHg, including temperature changes due to global warming, sea level rise, food web alterations due to introduced species and other causes, and changes in sediment supply. Other options for reducing or mitigating exposure and risk include controlling bioaccumulation, cleanup of contaminated sites, and reducing other factors (e.g., habitat availability) that limit at-risk wildlife populations.

Beliefs about responsibilities, the aims of therapy and the structure of the therapy process: a qualitative study of caseload management issues in child health occupational therapy.

BACKGROUND: Individual therapists' behaviour contributes to overall caseload management in therapy services. Therapists' caseload management (i.e. actions in relation to assessment, treatment and discharging) is likely to relate to their beliefs about caseload management; it may be possible to change therapists' caseload management by changing their beliefs. This study explored children's occupational therapists' beliefs about caseload management with a view to designing a caseload management intervention. METHODS: Twenty-five therapists from six NHS Scotland Health Boards were interviewed using a semi-structured format. Interviews were transcribed verbatim, and the interview transcripts were analysed for emerging themes. A proportion of transcripts were independently read and coded, and the themes were validated through critical discussion. RESULTS: Key issues emerged concerning therapists' beliefs about their responsibilities, the aims of therapy and the structure of the therapy process. Therapists expressed a strong sense of professional duty/responsibility, but the interpretations of what this duty/responsibility was differed between therapists. For example, therapists expressed highly contrasting beliefs about the goals and purpose of therapy and the ways in which therapy processes should be structured. Some therapists promoted an approach structured around clients' goals, while others focused more on relationship building. CONCLUSIONS: Therapists' beliefs about caseload management differ considerably; these differences could translate to variation in therapists' intentions and behaviours. Implications for practice, policy and future research were identified, as were implications for the way clinicians' caseload management is theorized.

Health inequalities in England, Scotland and Wales: stakeholders' accounts and policy compared.

OBJECTIVES: The election of a Labour government in 1997 brought the issue of health inequalities firmly back on to the policy agenda across the UK. Since then, in the wake of devolution, the need to tackle health inequalities has been highlighted as a policy priority in all three mainland UK countries, albeit with varying degrees of emphasis. This paper reports on a major cross-national study, funded by the Economic and Social Research Council, investigating how National Health Service bodies, local councils and partnerships make sense of their work on health inequalities, and examining the difference made by the contrasting approaches that have been taken to performance assessment in England, Wales and Scotland. STUDY DESIGN: Case studies, semi-structured interviews and analysis of key policy statements. METHODS: In order to explore how health inequalities have been approached by the three governments (noting that there was a change in governments in Wales and Scotland during this time), key policy statements published between May 1997 and May 2007 were analysed. Concurrently, data from stakeholder interviews carried out in 2006 in case study areas in each country were analysed to determine the extent of alignment between policy and practice at local level. RESULTS: This paper suggests that claims about the extent of health policy divergence in post-devolution Britain may have been exaggerated. It finds that, whilst the three countries have taken differing approaches to performance assessment and the setting of targets, policy approaches to health inequalities up until 2007 appear to have been remarkably similar. Furthermore, the first round of interview data suggest that variations in local understandings of, and responses to, health inequalities cannot always be clearly distinguished along national lines. CONCLUSIONS: Based on the policy analysis, devolution in the UK does not appear to have resulted in substantively different national policy approaches to health inequalities. Indeed, the overall analysis suggests that (prior to the 2007 elections in Scotland and Wales) the differences between local areas within countries may be of as much interest as those between countries.

Bifidobacterium animalis subsp. lactis 420 mitigates the pathological impact of myocardial infarction in the mouse.

There is a growing appreciation that our microbial environment in the gut plays a critical role in the maintenance of health and the pathogenesis of disease. Probiotic, beneficial gut microbes, administration can directly attenuate cardiac injury and post-myocardial infarction (MI) remodelling, yet the mechanisms of cardioprotection are unknown. We hypothesised that administration of Bifidobacterium animalis subsp. lactis 420 (B420), a probiotic with known anti-inflammatory properties, to mice will mitigate the pathological impact of MI, and that anti-inflammatory T regulatory (Treg) immune cells are necessary to impart protection against MI as a result of B420 administration. Wild-type male mice were administered B420, saline or Lactobacillus salivarius 33 (Ls-33) by gavage daily for 14 or 35 days, and underwent ischemia/reperfusion (I/R). Pretreatment with B420 for 10 or 28 days attenuated cardiac injury from I/R and reduced levels of inflammatory markers. Depletion of Treg cells by administration of anti-CD25 monoclonal antibodies eliminated B420-mediated cardio-protection. Further cytokine analysis revealed a shift from a pro-inflammatory to an anti-inflammatory environment in the probiotic treated post-MI hearts compared to controls. To summarise, B420 administration mitigates the pathological impact of MI. Next, we show that Treg immune cells are necessary to mediate B420-mediated protection against MI. Finally, we identify putative cellular, epigenetic and/or post-translational mechanisms of B420-mediated protection against MI.

Evaluation of consumable household products for decontaminating retail skinless, boneless chicken breasts.

The effect of 15 consumable products, including juices, wines, and vinegar, used as rinsing agents on microbial loads of retail skinless, boneless chicken breasts was evaluated in two studies. Ten breasts were rinsed for 1 min with each solution. Samples were swabbed before and after rinsing with a cellulose sponge and evaluated for total aerobic (APC), total coliform (TCC), and generic Escherichia coli counts by Petrifilm methods. No differences were found in initial APC or TCC in either study, with initial mean APC ranging from 5.30 to 7.05 log CFU/cm2 and initial mean TCC ranging from 2.21 to 3.36 log CFU/cm2. In study 1, the APC for breasts rinsed with distilled white vinegar (3.22 log CFU/cm2) was lower than for those rinsed with all other solutions except cranberry juice cocktail (3.86 log CFU/cm2). The TCC for breasts rinsed with distilled white vinegar (0.00 log CFU/cm2) and cranberry juice cocktail (0.20 log CFU/cm2) were lower than those for all other solutions except 10% NaCl (0.43 log CFU/cm2) and 10% NaHCO3 (0.48 log CFU/cm2). In study 2, APC values for breasts rinsed with red wine (5.29 log CFU/cm2) and white wine (5.32 log CFU/cm2) were lower than for breasts rinsed with the other three solutions. The TCC after rinsing with chicken broth (4.48 log CFU/cm2) was higher than for all other solutions except Italian dressing. Although distilled white vinegar was the most effective rinsing agent, all solutions produced lower counts after rinsing, indicating that consumers could use rinsing to remove microorganisms from chicken breast surfaces prior to cooking.

A population-based comparison of the clinical course of children and adults with AIDS.

OBJECTIVE: To examine the association of clinical complications and age at diagnosis with survival for a cohort of children and adults with AIDS. DESIGN: A population-based analysis of 734 children and 5584 adults diagnosed with AIDS from 1985 to 1990 in New York State. RESULTS: The initial AIDS-defining diagnoses for 68% of children were lymphoid interstitial pneumonitis or infections specified in the Centers for Disease Control and Prevention's (CDC) pediatric AIDS case definition but not the CDC's 1987 adult AIDS case definition. Of opportunistic infections in both case definitions, Pneumocystis carinii pneumonia (PCP) was the most common initial AIDS diagnosis, occurring in 53% of adults, 47% of children aged < 6 months at diagnosis (n = 122) and 14% aged > or = 6 months at diagnosis (n = 612). Median survival after AIDS diagnosis was 62 months for all children compared with 11 months for adults. For children initially diagnosed with conditions only in the pediatric case definition, median survival ranged from 27 to 62 months compared with less than 12 months for children and adults with PCP. Compared with children aged 6-54 months, the estimated hazards of death for younger and older children were 2.06 [95% confidence interval (CI), 1.48-2.86] and 1.54 (95% CI, 1.10-2.16), respectively. CONCLUSION: Children survived significantly longer than adults after AIDS diagnosis, but their survival varied by age at diagnosis. Differences in the types of common initial AIDS-defining diagnoses appear to contribute to the observed differences in survival.

The relationship of clinic experience with advanced HIV and survival of women with AIDS.

OBJECTIVE: Hospital and physician experience have been linked to improved outcomes for persons with HIV. Because many HIV-infected patients receive care in clinics, we studied clinic HIV experience and survival for women with AIDS. DESIGN: Retrospective cohort study of women with AIDS whose dominant sources of care were clinics. Clinic HIV experience was estimated as the cumulative number of Medicaid enrollees with advanced HIV who used a particular clinic as their dominant provider up to the year of the patient's AIDS diagnosis: low experience (< 20 patients), medium (20-99 patients), high (> or = 100 patients). Proportional hazards models examined relationships between experience and survival. SETTING: A total of 117 New York State clinics. PATIENTS: A total of 887 New York State Medicaid-enrolled women diagnosed with AIDS in 1989-1992. MAIN OUTCOME MEASURE: Survival after AIDS diagnosis. RESULTS: In later study years (1991-1992), patients in high experience clinics had an approximately 50% reduction in the relative hazard of death (0.53; 95% confidence interval, 0.35-0.82) compared with patients in low experience clinics. Adjusting for demographic and clinical variables, 71% of patients in high experience clinics were alive 21 months after diagnosis compared with 53% in low experience clinics. Experience and survival were not significantly associated in the early study years (1989-1990). CONCLUSIONS: In more recent years, women with AIDS receiving care in high experience clinics survived longer after AIDS diagnosis than those in low experience clinics, providing further evidence of a relationship between provider HIV experience and outcomes.

The AIDS-defining diagnosis and subsequent complications: a survival-based severity index.

To define a survival-based severity measure for AIDS, we convened a panel of AIDS experts who identified factors influencing AIDS prognosis and estimated the impact of prognostic factors on survival time. The resulting conceptual model included 19 AIDS-defining conditions and 80 subsequent AIDS-related complications. This model was tested on longitudinal disease histories of 3,937 AIDS patients in the New York State Medicaid Program diagnosed between 1983 and 1986 and followed through 1988. The initial AIDS diagnosis and complications within 3 months of AIDS onset were identified from coded diagnoses recorded on inpatient and outpatient claims. Three AIDS-defining diagnosis groups were created; survival times from least to most severe group were 25, 10, and 7 months. To determine the influence of subsequent complications on risk of death, the survival times associated with combinations of defining diagnosis groups and four severity levels of subsequent complications were determined. Median survival ranged from 43 months for the least severe defining diagnosis group without early complications to 12 months for the group with severe defining diagnoses and serious complications. The matrix of AIDS-defining diagnoses and complications was divided into four severity categories with significantly different survival curves. This severity measure uses longitudinal data commonly available to clinicians and researchers to create distinct AIDS prognostic categories.

Health care delivery, zidovudine use, and survival of women and men with AIDS.

The aim of this study was to define predictors of survival for women and men after AIDS diagnosis. We examined health care delivery and drug therapy in the year before AIDS diagnosis for continuously enrolled New York State Medicaid beneficiaries with AIDS in 1988-1990. We examined the association of these factors with survival after AIDS diagnosis. Of 1,077 women and 1,871 men, 60% of both gender groups were drug users. In both risk groups, women had more outpatient visits than men but were equally likely to visit an AIDS specialist. In those who were not drug users, men were twice as likely as women to receive either zidovudine or Pneumocystis carinii pneumonia prophylaxis. No difference appeared among drug users. Survival after AIDS diagnosis was similar by gender for those who were not drug users (RR = 1.09; 95% CI = 0.90-1.33). In drug users, women had a slightly lower risk of death than men (RR = 0.84; 95% CI = 0.72-0.98). Risk of death after AIDS diagnosis was higher for persons starting zidovudine earlier in both risk groups. Among drug users, women received more ambulatory care and survived slightly longer than men. Among those who were not drug users, survival was similar by gender even after adjusting for differences in care.

Comparison of Duchenne and normal myoblasts from a heterozygote.

To test the hypothesis that the Duchenne muscular dystrophy gene limits the proliferation of myoblasts, we studied myoblasts from a woman who was a carrier of the Duchenne gene and also heterozygous for glucose-6-phosphate dehydrogenase (G6PD), an X-linked enzyme. G6PD-A and G6PD-B cells did not differ in proliferative capacity, implying no difference in proliferative capacity of cells bearing the Duchenne gene or the normal allele.

Neurodevelopment of preterm infants: neonatal neurosonographic and serum bilirubin studies.

In this study of 249 preterm infants of less than 34 weeks' gestation, the relationships between maximal serum total bilirubin concentrations during the neonatal period, neonatal cranial ultrasonographic abnormalities, and severe neurodevelopmental sequelae are described. The subjects, who were selected on the basis of serial cranial ultrasonographic findings, had repeated neurologic and developmental examinations during late infancy and early childhood that established the presence (n = 45) or absence (n = 204) of spastic forms of cerebral palsy. Of the 204 subjects without cerebral palsy, 23 scored abnormally low on standardized developmental testing during early childhood. All but seven of the subjects with cerebral palsy had grade III/IV intracranial hemorrhage or moderate to severe periventricular echogenicity or both, ultrasonographic abnormalities that probably reflect a disruption in the blood-brain barrier as well as extravasation of blood into brain tissue; however, analysis of the data did not suggest that these cranial ultrasonographic abnormalities increased either the maximum serum bilirubin concentration during the neonatal period or the susceptibility of the subjects to neurologic damage from hyperbilirubinemia. Also, there was no evidence to suggest that bilirubinemia in the range studied (2.3 to 22.5 mg/100 mL total serum bilirubin) was causally related to cerebral palsy, early developmental delay, or the development of periventricular cysts in this population of preterm infants.(ABSTRACT TRUNCATED AT 250 WORDS)

Mechanical ventilation in preterm infants: neurosonographic and developmental studies.

Surviving preterm infants of less than 34 weeks' gestation who were selected on the basis of serial cranial ultrasonographic findings during their nursery course had repeated neurologic and developmental examinations during late infancy and early childhood that established the presence (n = 46) or absence (n = 205) of spastic forms of cerebral palsy. Of the 205 infants without cerebral palsy, 22 scored abnormally low on standardized developmental testing during early childhood. The need for mechanical ventilation beginning on the first day of life (n = 92) was significantly related to gestational age, birth weight, Apgar scores, patent ductus arteriosus, grade III/IV intracranial hemorrhage, large periventricular cysts, and the development of cerebral palsy. In the 192 mechanically ventilated infants, vaginal bleeding during the third trimester, low Apgar scores, and maximally low PCO2 values during the first 3 days of life were significantly related to large periventricular cysts (n = 41) and cerebral palsy (n = 43), but not to developmental delay in the absence of cerebral palsy (n = 18). The severity of intracranial hemorrhage in mechanically ventilated infants was significantly associated with gestational age and maximally low measurements of PCO2 and pH, but not with Apgar scores or maximally low measurements of PO2. Logistic regression analyses controlling for possible confounding variables disclosed that PCO2 values of less than 17 mm Hg during the first 3 days of life in mechanically ventilated infants were associated with a significantly increased risk of moderate to severe periventricular echodensity, large periventricular cysts, grade III/IV intracranial hemorrhage, and cerebral palsy. Neurosonographic abnormalities were highly predictive of cerebral palsy independent of PCO2 measurements.(ABSTRACT TRUNCATED AT 250 WORDS)

High-frequency jet ventilation in the early management of respiratory distress syndrome is associated with a greater risk for adverse outcomes.

OBJECTIVE: The objective of this investigation was to determine if high-frequency jet ventilation (HFJV) used early in the treatment of premature infants with respiratory distress syndrome was effective in reducing pulmonary morbidity without increasing the occurrence of adverse neurologic outcomes. STUDY DESIGN: A total of 73 premature infants who met the inclusion criteria (gestational age of less than 33 weeks, birth weight of more than 500 g, age of less than 24 hours, need for assisted ventilation with peak inspiratory pressure of more than 16 and FIO2 more than 0.30, and roentgenographic evidence of respiratory distress syndrome) were randomized to either conventional (n = 36) or to high-frequency jet (n = 37) ventilation. Our goals were to maintain the infants on the assigned ventilator for at least 7 days unless they could either be extubated or meet crossover criteria. Univariate analyses were initially used to compare the two groups. Stepwise logistic regression was subsequently used to assess whether various factors independently influenced adverse outcomes. RESULTS: The two groups of infants were similar in all obstetrical, perinatal, and neonatal demographic characteristics. The mean birth weight and gestational age in the conventional group were 930 g and 26.6 weeks and in the HFJV group, 961 g and 26.9 weeks. The infants were randomized at similar ages (7.1 and 7.3 hours of life, respectively). Their prerandomization ventilator settings and arterial blood gases were nearly identical. There were no differences in pulmonary outcomes (occurrence of air leaks, need for oxygen or ventilation at 36 weeks postconception), and there were no differences in the mean number of days oxygen was required, number of days ventilated, or length of hospital stay. Infants ventilated with HFJV were significantly more likely to develop cystic periventricular leukomalacia (10 vs 2, P = .022) or to have a poor outcome (grade IV hemorrhage, cystic periventricular leukomalacia, or death) (17 vs 7, P = .016). Logistic regression analysis revealed HFJV to be a significant independent predictor of both cystic periventricular leukomalacia and a poor outcome. The presence of hypocarbia was not an independently significant predictor of adverse outcomes. CONCLUSIONS: With the HFJV treatment strategy that we used, use of the high-frequency jet ventilator in the early management of premature infants with respiratory distress syndrome resulted in significantly more adverse outcomes than in those treated with conventional mechanical ventilation.

Effects of hypocarbia on the development of cystic periventricular leukomalacia in premature infants treated with high-frequency jet ventilation.

BACKGROUND AND OBJECTIVE: Previous data from our institution indicate that mechanically ventilated premature infants are at increased risk for cystic periventricular leukomalacia (CPVL), particularly if hypocapnia occurs. High-frequency jet ventilation (HFJV) may produce substantial hypocapnia. We sought to investigate whether hypocapnia during HFJV is associated with the development of CPVL. METHODS: Sixty-seven premature infants (mean gestational age, 27.2 weeks; mean birth weight, 1001 g) underwent HFJV for a mean of 44 (range, 8 to 70) hours during the first 3 days of life. All infants were followed with serial neurosonograms at least weekly until 6 to 8 weeks of age and every 2 to 4 weeks thereafter until discharge. To assess the cumulative effects of hypotension, acidosis, hypoxemia, and hypocarbia during the first 3 days of life on the development of PVL, we developed a quantitative assessment in which we assigned threshold levels at particular critical values of these parameters (such as a mean PaCO2 of 20 mm Hg) and calculated an area above the curve between longitudinally connected values of these parameters and the threshold levels. RESULTS: Nine of the 67 infants died before 21 days of life. Of the 58 who survived beyond 21 days, large CPVL (> 5 mm in size) developed in 18 infants. Infants with cysts were similar in birth weight, gestational age, and virtually all other antepartum, intrapartum, and postpartum parameters compared with the 40 neonates in whom CPVL did not develop. However, infants with CPVL were significantly more likely to have moderate or severe periventricular echodensities preceding development of CPVL and periventricular echodensities that persisted for a longer period. We did not find an effect of hypotension, acidosis, or hypoxemia on the development of CPVL. There were no differences in the mean PaCO2, the absolute low PaCO2 values, the ranges of low PaCO2 between groups, or area above the curve measurements at threshold levels of 15 and 20 mm Hg, respectively. However, logistic regression analysis revealed that infants with CPVL were independently significantly more likely to have greater cumulative hypocarbia below a threshold level of 25 mm Hg during the first day of life (odds ratio, 5.43; 95% confidence interval, 1.33 to 22.2). CONCLUSIONS: Hypocarbia produced by treatment with HFJV during the first 3 days of life is associated with the subsequent development of CPVL. The mechanisms for the development of CPVL among premature infants treated with HFJV need to be established.

Clinical evaluation of some phosphorus bone-imaging agents: concise communication.

Four different Tc-99m labeled phosphorus-based bone-imaging agents were compared by a scan-evaluation technique in which the skeletal uptake was visually assessed at selected sites. A detailed statisticalanalysis of scans, by each of three independent evaluators, on a total of 140 different patients showed that two of the agents (based on pyro- and on trimetaphosphate) were superior. The statistical analysis showed good agreement between the investigators and consistency in thier repeat evaluations.