The use of a multiplex real-time PCR assay for diagnosing acute respiratory viral infections in children attending an emergency unit

•

Evaluate the use of multiplex real-time PCR for diagnosing respiratory infections.

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857/966 samples from 914 children were positive for one or multiple viruses.

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Respiratory syncytial virus and rhinovirus were the most prevalent.

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Co-infections were associated with severe respiratory symptoms.

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The spread of respiratory viruses returned to the one it was before the flu outbreak.

Background

The use of a multiplex molecular technique to identify the etiological pathogen of respiratory viral infections might be a support as clinical signs are not characteristic.

Objectives

The aim of the study was to evaluate a multiplex molecular real-time assay for the routine diagnosis of respiratory viruses, to analyze the symptoms associated with the pathogens detected and to determine the spread of virus during the period.

Study design

Respiratory samples were collected from children presenting with respiratory symptoms and attending the emergency unit during the 2010–2011 winter seasons. Samples were tested with the multiplex RespiFinder^® 15 assay (PathoFinder™) which potentially detects 15 viruses.

Results

857 (88.7%) of the 966 samples collected from 914 children were positive for one (683 samples) or multiple viruses (174 samples). The most prevalent were the respiratory syncytial virus (39.5%) and the rhinovirus (24.4%). Influenza viruses were detected in 139 (14.4%) samples. Adenovirus was detected in 93 (9.6%) samples, coronaviruses in 88 (9.1%), metapneumovirus in 51 (5.3%) and parainfluenzae in 47 (4.9%). Rhinovirus (40%) was the most prevalent pathogen in upper respiratory tract infections while respiratory syncytial virus (49.9%) was the most prevalent in lower respiratory tract infections. Co-infections were associated with severe respiratory symptoms.

Conclusion

The multiplex assay detected clinically important viruses in a single genomic test and thus will be useful for detecting several viruses causing respiratory tract disorders.

CeasIng Cpap At standarD criteriA (CICADA): impact on weight gain, time to full feeds and caffeine use

INTRODUCTION

In our previous randomised controlled trial (RCT), we have shown in preterm babies (PBs) <30 weeks gestation that CeasIng Cpap At standarD criteriA (CICADA (method 1)) compared with cycling off continuous positive airway pressure (CPAP) gradually (method 2) or cycling off CPAP gradually with low flow air/oxygen during periods off CPAP (method 3) reduces CPAP cessation time in PBs <30 weeks gestation.

METHOD

This retrospective study reviewed weight gain, time to reach full feeds and time to cease caffeine in PBs previously enrolled in the RCT.

RESULTS

Data were collected from 162 of the 177 PBs, and there was no significant difference in the projected weight gain between the three methods. Based on intention to treat, the time taken to reach full feeds for all three methods showed no significant difference. However, post hoc analysis showed the CICADA method compared with cycling off gradually just failed significance (30.3±1.6 vs 31.1±2.4 (weeks corrected gestational age (Wks CGA±SD)), p=0.077). Analysis of time to cease caffeine showed there was a significant difference between the methods with PBs randomised to the CICADA method compared with the cycling off method ceasing caffeine almost a week earlier (33.6±2.4 vs 34.5±2.8 (Wks CGA±SD), p=0.02).

CONCLUSIONS

This retrospective study provides evidence to substantiate the optimum method of ceasing CPAP; the CICADA method, does not adversely affect weight gain, time to reach full feeds and may reduce time to cease caffeine in PBs <30 weeks gestation.

Cardiovascular function in children who had chronic lung disease of prematurity

OBJECTIVES

Although increased pulmonary arterial pressure is common in infancy in preterm infants who develop chronic lung disease of prematurity (CLD), it is unknown if the increase persists into childhood. We, therefore, assessed if 8-12-year-old children with documented CLD in infancy had evidence of right ventricular dysfunction or pulmonary arterial hypertension at rest or in response to acute hypoxia when compared to preterm and term-born controls.

METHODS

We studied 90 children: 60 born at ≤32 weeks of gestation (28 with CLD and 32 preterm controls), and 30 term-born controls. All had echocardiography including myocardial velocity imaging, at rest and while breathing 15% oxygen and 12% oxygen for 20 min each.

RESULTS

Baseline oxygen saturation, heart rate, blood pressure and echocardiographic markers of left and right ventricular function were similar in all three groups. While breathing 12% oxygen, the oxygen saturation decreased to 81.9% in the CLD group compared to 85.1% (p<0.05) and 84.7% (p<0.01) in the preterm and term controls, respectively. In response to hypoxia, all three groups showed increases in velocity of tricuspid regurgitation, end-diastolic velocity of pulmonary regurgitation, and right ventricular relaxation time; and decreases in pulmonary arterial acceleration time and the ratio of right ventricular acceleration time to ejection time. However, there were no differences between groups.

CONCLUSIONS

Childhood survivors of CLD have comparable left and right ventricular function at 8-12 years of age to preterm and term-born children, and no evidence of increased pulmonary arterial pressure even after hypoxic exposure.

Change in practice after the Surfactant, Positive Pressure and Oxygenation Randomised Trial

OBJECTIVE

To test the hypothesis that the proportion of endotracheal intubation (ETI) in the delivery room (DR) decreased in Neonatal Research Network (NRN) centres after the National Institute of Child Health and Human Development NRN Surfactant, Positive Pressure, and Oxygenation Randomised Trial (SUPPORT).

DESIGN

Retrospective cohort study using the prospective NRN generic database.

SETTING

Eleven centres that participated in the SUPPORT trial and remained part of the NRN. Preterm neonates 24(0/7)-27(6/7) weeks' gestational age enrolled in the SUPPORT trial were randomised to: (1) DR continuous positive airway pressure or DR ETI with early surfactant administration; and (2) oxygen saturation targets of 85-89% or 91-95%. The prior NRN feasibility trial had assessed the feasibility of randomisation to continuous positive airway pressure versus ETI.

PATIENTS

Infants 24(0/7)-27(6/7) weeks' gestational age, excluding infants with syndromes or major malformations and those on comfort care only.

MAIN OUTCOME MEASURE

Proportion of DR ETI.

RESULTS

The proportion of DR ETI decreased significantly in the group of infants from centres that had not participated in the feasibility trial (91% before vs 75% after SUPPORT, adjusted relative risk 0.86, 95% CI 0.83-0.89, p<0.0001) but not in the group of infants from the other centres, where the proportion of ETI was already lower prior to initiation of the SUPPORT trial (61% before vs 58% after SUPPORT, adjusted relative risk 0.96, 95% CI 0.89 to 1.05, p=0.40).

CONCLUSION

This study shows that DR ETI changed after SUPPORT only in NRN centres that had not participated in a similar trial.

TRIAL REGISTRATION NUMBER

NCT00063063 (GDB) and NCT00233324 (SUPPORT).

Intravenous salbutamol for childhood asthma: evidence-based medicine?

Intravenous salbutamol is commonly used to treat children with severe asthma unresponsive to inhaled β2-agonist therapy. However, in this setting, there is little clinical trial data demonstrating its effectiveness. Additionally, there are significant concerns that intravenous salbutamol-dosing recommendations for children with acute asthma are excessive, and unnecessarily raise the potential for adverse reactions, such as lactic acidosis and tachycardia which, by increasing respiratory workload, exacerbate respiratory failure. Here, we review salbutamol clinical pharmacology and toxicology, evidence relating to its use in acute asthma and highlight gaps in the evidence base.

Ambient Coarse Particulate Matter and Human Health: A Systematic Review and Meta-Analysis

Airborne particles have been linked to increased mortality and morbidity. As most research has focused on fine particles (PM2.5), the health implications of coarse particles (PM10-2.5) are not well understood. We conducted a systematic review and meta-analysis of associations for short- and long-term PM10-2.5 concentrations with mortality and hospital admissions. Using 23 mortality and 10 hospital admissions studies, we documented suggestive evidence of increased morbidity and mortality in relation to higher short-term PM10-2.5 concentrations, with stronger relationships for respiratory than cardiovascular endpoints. Reported associations were highly heterogeneous, however, especially by geographic region and average PM10-2.5 concentrations. Adjustment for PM2.5 and publication bias resulted in weaker and less precise effect estimates, although positive associations remained for short-term PM10-2.5 concentrations. Inconsistent relationships between effect estimates for PM10-2.5 and correlations between PM10-2.5 and PM2.5 concentrations, however, indicate that PM10-2.5 associations cannot be solely explained by co-exposure to PM2.5. While suggestive evidence was found of increased mortality with long-term PM10-2.5 concentrations, these associations were not robust to control for PM2.5. Additional research is required to better understand sources of heterogeneity of associations between PM10-2.5 and adverse health outcomes.

Anxiety, depression and self-esteem in children with well-controlled asthma: case-control study

OBJECTIVE

Although asthma has been linked to psychological morbidity, this relationship may be confounded by poor asthma control. We aimed to compare the prevalence of anxiety, depression and low level of self-esteem in children with well-controlled asthma with that of healthy peers.

SETTING

Dedicated asthma clinic in a general hospital.

PATIENTS

70 patients with mostly well-controlled asthma and 70 matched healthy controls.

INTERVENTIONS

Comprehensive asthma education, management and follow-up for asthma patients.

MAIN OUTCOME MEASURES

Validated Dutch versions of the Childhood Depression inventory (CDI), Revised Fear Survey for Children (RFSC), Self Perception Profile for Children (SPC-C) and Adolescents (SPC-A) and State-Trait Anxiety Inventory for Children (STAIC). Asthma control assessed by asthma control questionnaire.

RESULTS

No significant differences were found in total scores between asthmatics and controls (95% CI for difference -0.2 to 2.9 for CDI, -5.9 to 11.2 for RFSC, -19.9 to 6.3 for SPC-C, -24.1 to 5.0 for SPC-A and -2.7 to 0.01 for STAIC). There were also no significant differences between asthmatics and controls in the prevalence of scores exceeding cut-off levels for clinically relevant anxiety (13.3 vs 13.0%, p=0.605), depression (12.9 vs 5.7%, p=0.243) or low self-esteem (21.4 vs 12.9%, p=0.175). A significant correlation was found between poorer asthma control and CDI (p=0.012) and anxiety trait symptoms (p<0.001).

CONCLUSIONS

Children with well-controlled asthma enrolled in a comprehensive asthma management programme do not have an increased risk of anxiety, depression and poor self-esteem. Earlier reports of psychological comorbidity in asthma may have been related to inadequately controlled asthma.

15-minute consultation: a structured approach to the assessment of chest pain in a child

This article aims to provide a concise, structured approach to the child with chest pain. Chest pain is a common presenting symptom in children but, unlike in adults, the cause is rarely cardiac. We review the main causes of chest pain in children and discuss the important features that may alert those assessing paediatric chest pain to serious underlying pathology. In the vast majority of cases, reassurance is all that is required and a thorough initial consultation can exclude rare, serious disease and provide vital reassurance to children and families.

Spontaneous swallowing occurs during autoresuscitation in the in situ brainstem preparation of rat

Previous studies report that upper airway reflexes are operational during autoresuscitation from respiratory arrest. We investigated swallowing/breathing interactions, measured by recording of vagal (VNA) and phrenic nerve activities (PNA), during autoresuscitation in the in situ perfused brainstem preparation of juvenile rats. During the initial surgery, respiratory arrest was induced by exsanguination and cooling. Reperfusion (i.e. re-oxygenation and re-warming) of the brainstem circuits was associated with frequent spontaneous swallowing before resumption of respiration (n=6, 'stage 1 autoresuscitation'). When recovered, the respiratory pattern was transiently apneustic-like ('stage 2 autoresuscitation'). Spontaneous swallowing often occurred at the end of the prolonged PNA (n=9/12). Successful autoresuscitation was characterised by re-establishment of the 3 phase respiratory motor pattern and no spontaneous swallowing. Pharmacological inhibition (isoguvacine, 10 mM, 50-75 nl; n=10) of the Kölliker-Fuse nucleus (KF) mimicked stage 2 autoresuscitation. However, the frequency of spontaneous swallowing after KF inhibition did not correlate with subsequent recovery of the eupneic respiratory motor pattern.

Diurnal and twenty-four hour patterning of human diseases: cardiac, vascular, and respiratory diseases, conditions, and syndromes

Various medical conditions, disorders, and syndromes exhibit predictable-in-time diurnal and 24 h patterning in the signs, symptoms, and grave nonfatal and fatal events, e.g., respiratory ones of viral and allergic rhinorrhea, reversible (asthma) and non-reversible (bronchitis and emphysema) chronic obstructive pulmonary disease, cystic fibrosis, high altitude pulmonary edema, and decompression sickness; cardiac ones of atrial premature beats and tachycardia, paroxysmal atrial fibrillation, 3rd degree atrial-ventricular block, paroxysmal supraventricular tachycardia, ventricular premature beats, ventricular tachyarrhythmia, symptomatic and non-symptomatic angina pectoris, Prinzmetal vasospastic variant angina, acute (non-fatal and fatal) incidents of myocardial infarction, sudden cardiac arrest, in-bed sudden death syndrome of type-1 diabetes, acute cardiogenic pulmonary edema, and heart failure; vascular and circulatory system ones of hypertension, acute orthostatic postprandial, micturition, and defecation hypotension/syncope, intermittent claudication, venous insufficiency, standing occupation leg edema, arterial and venous branch occlusion of the eye, menopausal hot flash, sickle cell syndrome, abdominal, aortic, and thoracic dissections, pulmonary thromboembolism, and deep venous thrombosis, and cerebrovascular transient ischemic attack and hemorrhagic and ischemic stroke. Knowledge of these temporal patterns not only helps guide patient care but research of their underlying endogenous mechanisms, i.e., circadian and others, and external triggers plus informs the development and application of effective chronopreventive and chronotherapeutic strategies.

Changes in blood gas transport of altitude native soccer players near sea-level and sea-level native soccer players at altitude (ISA3600)

Objectives

The optimal strategy for soccer teams playing at altitude is not known, that is, ‘fly-in, fly-out’ versus short-term acclimatisation. Here, we document changes in blood gas and vascular volumes of sea-level (Australian, n=20) and altitude (Bolivian, n=19) native soccer players at 3600 m.

Methods

Haemoglobin-oxygen saturation (Hb-sO₂), arterial oxygen content (CaO₂), haemoglobin mass (Hbmass), blood volume (BV) and blood gas concentrations were measured before descent (Bolivians only), together with aerobic fitness (via Yo-YoIR1), near sea-level, after ascent and during 13 days at 3600 m.

Results

At baseline, haemoglobin concentration [Hb] and Hbmass were higher in Bolivians (mean±SD; 18.2±1.0 g/dL, 12.8±0.8 g/kg) than Australians (15.0±0.9 g/dL, 11.6±0.7 g/kg; both p≤0.001). Near sea-level, [Hb] of Bolivians decreased to 16.6±0.9 g/dL, but normalised upon return to 3600 m; Hbmass was constant regardless of altitude. In Australians, [Hb] increased after 12 days at 3600 m to 17.3±1.0 g/dL; Hbmass increased by 3.0±2.7% (p≤0.01). BV decreased in both teams at altitude by ∼400 mL. Arterial partial pressure for oxygen (PaO₂), Hb-sO₂ and CaO₂ of both teams decreased within 2 h of arrival at 3600 m (p≤0.001) but increased over the following days, with CaO₂ overcompensated in Australians (+1.7±1.2 mL/100 mL; p≤0.001). Yo-YoIR1 was lower on the 3rd versus 10th day at altitude and was significantly related to CaO₂.

Conclusions

The marked drop in PaO₂ and CaO₂ observed after ascent does not support the ‘fly-in, fly-out’ approach for soccer teams to play immediately after arrival at altitude. Although short-term acclimatisation was sufficient for Australians to stabilise their CaO₂ (mostly due to loss of plasma volume), 12 days appears insufficient to reach chronic levels of adaption.

The impact of altitude on the sleep of young elite soccer players (ISA3600)

Background

Altitude training is used by elite athletes to improve sports performance, but it may also disrupt sleep. The aim of this study was to examine the effects of 2 weeks at high altitude on the sleep of young elite athletes.

Methods

Participants (n=10) were members of the Australian under-17 soccer team on an 18-day (19-night) training camp in Bolivia, with six nights at near sea level in Santa Cruz (430 m) and 13 nights at high altitude in La Paz (3600 m). Sleep was monitored using polysomnography during a baseline night at 430 m and three nights at 3600 m (immediately after ascent, 1 week after ascent and 2 weeks after ascent). Data were analysed using effect size statistics.

Results

All results are reported as comparisons with baseline. Rapid eye movement (REM) sleep was likely lower immediately upon ascent to altitude, possibly lower after 1 week and similar after 2 weeks. On all three nights at altitude, hypopneas and desaturations were almost certainly higher; oxygen saturation was almost certainly lower; and central apnoeas, respiratory arousals and periodic breathing were very likely higher. The effects on REM sleep were common to all but one participant, but the effects on breathing were specific to only half the participants.

Conclusions

The immediate effects of terrestrial altitude of 3600 m are to reduce the amount of REM sleep obtained by young elite athletes, and to cause 50% of them to have impaired breathing during sleep. REM sleep returns to normal after 2 weeks at altitude, but impaired breathing does not improve.

The individual response to training and competition at altitude

Performance in athletic activities that include a significant aerobic component at mild or moderate altitudes shows a large individual variation. Physiologically, a large portion of the negative effect of altitude on exercise performance can be traced to limitations of oxygen diffusion, either at the level of the alveoli or the muscle microvasculature. In the lung, the ability to maintain arterial oxyhaemoglobin saturation (SaO₂) appears to be a primary factor, ultimately influencing oxygen delivery to the periphery. SaO₂ in hypoxia can be defended by increasing ventilatory drive; however, during heavy exercise, many athletes demonstrate limitations to expiratory flow and are unable to increase ventilation in hypoxia. Additionally, increasing ventilatory work in hypoxia may actually be negative for performance, if dyspnoea increases or muscle blood flow is reduced secondary to an increased sympathetic outflow (eg, the muscle metaboreflex response). Taken together, some athletes are clearly more negatively affected during exercise in hypoxia than other athletes. With careful screening, it may be possible to develop a protocol for determining which athletes may be the most negatively affected during competition and/or training at altitude.

Perioperative hypoxemia is common with horizontal positioning during general anesthesia and is associated with major adverse outcomes: a retrospective study of consecutive patients

Background

Reported perioperative pulmonary aspiration (POPA) rates have substantial variation. Perioperative hypoxemia (POH), a manifestation of POPA, has been infrequently studied beyond the PACU, for patients undergoing a diverse array of surgical procedures.

Methods

Consecutive adult patients with ASA I-IV and pre-operative pulmonary stability who underwent a surgical procedure requiring general anesthesia were investigated. Using pulse oximetry, POH was documented in the operating room and during the 48 hours following PACU discharge. POPA was the presence of an acute pulmonary infiltrate with POH.

Results

The 500 consecutive, eligible patients had operative body-positions of prone 13%, decubitus 8%, sitting 1%, and supine/lithotomy 78%, with standard practice of horizontal recumbency. POH was found in 150 (30%) patients. Post-operative stay with POH was 3.7 ± 4.7 days and without POH was 1.7 ± 2.3 days (p < 0.0001). POH rate varied from 14% to 58% among 11 of 12 operative procedure-categories. Conditions independently associated with POH (p < 0.05) were acute trauma, BMI, ASA level, glycopyrrolate administration, and duration of surgery. POPA occurred in 24 (4.8%) patients with higher mortality (8.3%), when compared to no POPA (0.2%; p = 0.0065). Post-operative stay was greater with POPA (7.7 ± 5.7 days), when compared to no POPA (2.0 ± 2.9 days; p = 0.0001). Conditions independently associated with POPA (p < 0.05) were cranial procedure, ASA level, and duration of surgery. POPA, acute trauma, duration of surgery, and inability to extubate in the OR were independently associated with post-operative stay (p < 0.05). POH, gastric dysmotility, acute trauma, cranial procedure, emergency procedure, and duration of surgery had independent correlations with post-operative length of stay (p < 0.05).

Conclusions

Adult surgical patients undergoing general anesthesia with horizontal recumbency have substantial POH and POPA rates. Hospital mortality was greater with POPA and post-operative stay was increased for POH and POPA. POH rates were noteworthy for virtually all categories of operative procedures and POH and POPA were independent predictors of post-operative length of stay. A study is needed to determine if modest reverse-Trendelenburg positioning during general anesthesia has a relationship with reduced POH and POPA rates.

Does failed chronic wet cough response to antibiotics predict bronchiectasis?

AIM

To determine whether a child with chronic wet cough and poor response to at least 4 weeks of oral antibiotics is more likely to have bronchiectasis.

METHODS

All chest multi-detector computerised tomography (MDCT) scans at a single paediatric tertiary hospital from April 2010 to August 2012 were reviewed retrospectively so as to identify those ordered by respiratory physicians for assessment of children with a chronic wet cough. Information regarding age, sex, ethnicity, indication for imaging and the response to at least 4 weeks of antibiotics before having the scan were recorded from their charts. The data were analysed using simple and multiple logistic regression.

RESULTS

Of the 144 (87 males) eligible children, 106 (65 males, 30 Indigenous) aged 10-199 months had MDCT scan evidence of bronchiectasis. Antibiotic data were available for 129 children. Among the 105 children with persistent cough despite at least 4 weeks of antibiotics, 88 (83.8%) had bronchiectasis, while of the 24 children whose cough resolved after antibiotics, only six (25.0%) received this diagnosis (adjusted OR 20.9; 95% CI 5.36 to 81.8). Being Indigenous was also independently associated with radiographic evidence of bronchiectasis (adjusted OR 5.86; 95% CI 1.20 to 28.5).

CONCLUSIONS

Further investigations including a MDCT scan should be considered in a child with a chronic wet cough that persists following 4 weeks of oral antibiotics. However, while reducing the likelihood of underlying bronchiectasis, responding well to a single prolonged course of antibiotics does not exclude this diagnosis completely.

Pulse oximetry in children

Pulse oximetry is routinely used in hospitals in high-income settings, but its theoretical basis is often poorly understood. This paper summarises the physiological background, technological basis and limitations of pulse oximetry.

Sleeping position and responses to a carbon dioxide challenge in convalescent prematurely born infants studied post-term

OBJECTIVES

To test the hypothesis that the ventilatory response to a carbon dioxide (CO2) challenge would be lower in the prone compared to the supine position in prematurely born infants studied post-term. To determine whether there were postural-related differences in respiratory drive, respiratory muscle strength, thoracoabdominal synchrony and/or lung volume.

DESIGN

Prospective cohort study.

SETTING

Tertiary neonatal unit.

PATIENTS

Eighteen infants (median gestational age 31 (range 22-32) weeks) were studied at a median of 5 (range 2-11) weeks post-term.

INTERVENTIONS

The ventilatory responses to three added carbon dioxide (CO2) levels (0% baseline, 2% and 4%) were assessed in the prone and supine positions.

MAIN OUTCOME MEASURES

The airway pressure change after the first 100 ms of an occluded inspiration (P0.1) (respiratory drive) and the maximum inspiratory pressure during crying with an occluded airway (Pimax) (respiratory muscle strength) were measured. The P0.1/Pimax ratio at each CO2 level and slope of the P0.1/Pimax response were calculated.

RESULTS

The mean P0.1 (p<0.05) and P0.1/Pimax (p<0.05) were higher and the functional residual capacity (p=0.031) lower in the supine compared to the prone position. The mean P0.1 and P0.1/Pimax increased independently of position as the percentage CO2 increased (p<0.001). There was no tendency for the differences in P0.1 and P0.1/Pimax between the prone and supine position to vary by CO2 level.

CONCLUSIONS

Convalescent, prematurely born infants studied post-term have a reduced respiratory drive, but not a lower ventilatory response to a CO2 challenge, in the prone compared to the supine position.

Gene therapy in cystic fibrosis

The principal cause of morbidity and mortality in cystic fibrosis (CF) is pulmonary disease, so the focus of new treatments in this condition is primarily targeted at the lungs. Since the cloning of the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene in 1989, there has been significant interest in the possibility of gene therapy as a treatment for CF. Early studies using viral vectors carrying a healthy CFTR plasmid highlighted the difficulties with overcoming the body's host defences. This article reviews the work on gene therapy in CF to date and describes the ongoing work of the UK CF Gene Therapy Consortium in investigating the potential of gene therapy as a treatment for patients with CF.

Challenges for inhaled drug discovery and development: Induced alveolar macrophage responses

Alveolar macrophage (AM) responses are commonly induced in inhalation toxicology studies, typically being observed as an increase in number or a vacuolated 'foamy' morphology. Discriminating between adaptive AM responses and adverse events during nonclinical and clinical development is a major scientific challenge. When measuring and interpreting induced AM responses, an understanding of macrophage biology is essential; this includes 'sub-types' of AMs with different roles in health and disease and mechanisms of induction/resolution of AM responses to inhalation of pharmaceutical aerosols. In this context, emerging assay techniques, the utility of toxicokinetics and the requirement for new biomarkers are considered. Risk assessment for nonclinical toxicology findings and their translation to effects in humans is discussed from a scientific and regulatory perspective. At present, when apparently adaptive macrophage-only responses to inhaled investigational products are observed in nonclinical studies, this poses a challenge for risk assessment and an improved understanding of induced AM responses to inhaled pharmaceuticals is required.

Conservative management of antenatally diagnosed cystic lung malformations

AIM

To review the outcome of all antenatally diagnosed conservatively managed congenital lung malformations (CLMs) managed at our centre.

METHODS

All patients diagnosed antenatally with cystic lung malformations from 2001 to 2011, at a tertiary referral paediatric surgical centre practising a policy of conservative management of asymptomatic cases, were retrospectively reviewed. Data were collected from medical case notes and radiology reports. Ethical approval was obtained from our institutional research and development department.

RESULTS

The complete records of 74 fetuses antenatally diagnosed with CLM were reviewed. There were 72 live births, at a median gestation of 39.6 weeks. Emergency lobectomy was performed in one symptomatic neonate. Elective lobectomies were performed at parental request in three asymptomatic infants, one of whom had a family history of synovial sarcoma. Two patients developed pneumonia in the affected lobe during early childhood and proceeded to lobectomy at the age of 3 years. One patient with a bronchopulmonary sequestration required embolisation for cyanotic episodes. The remaining 65 patients have been conservatively managed to date, and none have required hospital admission. Less than a quarter report mild respiratory symptoms such as cough or wheeze. Median follow-up is 5 years.

CONCLUSIONS

This retrospective cohort study of 74 consecutive CLMs diagnosed antenatally over a 10-year period demonstrates that most of these lesions will remain asymptomatic throughout childhood. Although the natural history of CLMs in later years remains to be elucidated, we hope that this report on medium-term outcomes will be useful to clinicians who undertake antenatal counselling and may inform the discussion on how best to manage these children.

Preventing severe respiratory syncytial virus disease: passive, active immunisation and new antivirals

In most high-income countries palivizumab prophylaxis is considered safe, efficacious and cost-effective for preventing respiratory syncytial virus (RSV) hospital admissions among specific subgroups of infants born preterm, with chronic lung disease or with congenital heart disease. Virtually all babies acquire RSV during infancy and previously healthy babies are not eligible to receive palivizumab. Emerging evidence suggests some benefit of palivizumab use in reducing recurrent wheeze among infants born preterm. Better longitudinal studies are needed to examine its clinical and cost-effectiveness on recurrent and chronic respiratory illness and associated healthcare burden on resources in the community and hospitals. Since 99% of child deaths attributed to RSV occur in resource poor countries where expensive prophylaxis is not available or affordable, palivizumab has limited potential to impact on the current global burden of RSV lower respiratory tract infection (LRTI). A range of candidate vaccines for active immunisation against RSV are now in clinical trials. Two promising new antivirals are also currently in phase I/II trials to test their effectiveness in preventing severe RSV LRTI. These agents may be effective in preventing severe disease and phase III studies are in development. In the absence of effective active immunisation against RSV infection, population level approaches to prevent severe RSV LRTI should continue to focus on reducing prenatal and environmental risk factors including prematurity, smoking and improving hygiene practices.

Epidemiology and clinical parameters of adult human immunodeficiency virus/acquired immunodeficiency syndrome at the initiation of antiretroviral therapy in South eastern Nigeria

Background:

Human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) has continued to ravage the teeming populations in Nigeria, with disastrous consequences. Despite many studies and progress on HIV/AIDS in Africa, the data on the status of the patients at the commencement of therapy is lacking.

Aim:

The aim of this study is to determine the demographic, clinical and some laboratory features of adult HIV/AIDS patients, seen at the commencement of antiretroviral therapy (ART) in Nnamdi Azikiwe University Teaching Hospital, Nnewi, south-east Nigeria between July 2002 and October 2004.

Subjects and Methods:

The study was a cross-sectional, descriptive study. Adult patients living with HIV/AIDS were studied using an interview administered questionnaire. Data was analyzed using Epi Info 2008 version 3.5.1.

Results:

A total of 400 respondents participated in this study. The mean age was 36.8 (8.8) years. Almost 60% patients were married and the HIV concordance rate was 53.3% (136/255). Nearly 30% of the families had at least one child positive for HIV. The most common associated risky behavior was injection administered in patent medicine stores 74.5%(302/400) and the most common clinical symptom was respiratory. Of the 400 patients recruited in this study, 19 (4.8%) were lost to follow-up on the 6 months’ visit, giving a follow-up rate of 95.2% (381/400). There was statistically significant difference in the mean body weight (P = 0.02), mean total white blood cell count (P < 0.001) and mean CD4⁺ count (P < 0.001) at presentation and after 6 months of ART therapy.

Conclusion:

HIV/AIDS patients present late and body weight, CD4⁺ count and total white blood cell count seemed to recover quickly on commencement of ART. The prevalence of concordance among couples and mother to child transmission rates tended to be high. Administration of injectable at patent medicine stores and multiple sexual partners are the most significant risk factors.

Non-invasive respiratory volume monitoring to detect apnea in post-operative patients: case series

Obstructive sleep apnea (OSA) is a potential independent risk factor for postoperative complications, adverse surgical outcomes, and longer hospital stays. Obese patients with OSA have increased post-operative complications. An estimated 25-30% of pre-operative patients are at a high risk for OSA. A novel, non-invasive respiratory volume monitor (RVM) has been developed to provide a real time respiratory curve demonstrating lung volumes as well as a continuous, display of minute ventilation, tidal volume and respiratory rate. Clinical application of this device in the post-anesthesia care unit (PACU) can "unmask" post-operative apneic events resulting from partial or complete airway collapse due to the residual effects of narcotic administration and volatile and/or intravenous anesthetics. Clinical examples from two patients, one with known OSA and one without a previous diagnosis of OSA, monitored in the PACU with RVM are presented here. Post-operatively both patients had an increase in apneic episodes with significant decreases in their MV during apneic episodes after opioid administration as compared to pre-op baseline. In addition, oxygen saturation, for both patients, which is an essential component of current respiratory monitoring remained normal in the cases presented, despite the significant decreases in MV. Continuous RVM monitoring demonstrates both changes in respiratory patterns and overall adequacy of ventilation, and allows practitioners to quantify the increase in the number and duration apneic episodes as a response to narcotic administration. These case studies demonstrate that a non-invasive respiratory volume monitoring system can detect and quantify respiratory disturbances that currently go undetected.

Decreased spinal synaptic inputs to phrenic motor neurons elicit localized inactivity-induced phrenic motor facilitation

Phrenic motor neurons receive rhythmic synaptic inputs throughout life. Since even brief disruption in phrenic neural activity is detrimental to life, on-going neural activity may play a key role in shaping phrenic motor output. To test the hypothesis that spinal mechanisms sense and respond to reduced phrenic activity, anesthetized, ventilated rats received micro-injections of procaine in the C2 ventrolateral funiculus (VLF) to transiently (~30min) block axon conduction in bulbospinal axons from medullary respiratory neurons that innervate one phrenic motor pool; during procaine injections, contralateral phrenic neural activity was maintained. Once axon conduction resumed, a prolonged increase in phrenic burst amplitude was observed in the ipsilateral phrenic nerve, demonstrating inactivity-induced phrenic motor facilitation (iPMF). Inhibition of tumor necrosis factor alpha (TNFα) and atypical PKC (aPKC) activity in spinal segments containing the phrenic motor nucleus impaired ipsilateral iPMF, suggesting a key role for spinal TNFα and aPKC in iPMF following unilateral axon conduction block. A small phrenic burst amplitude facilitation was also observed contralateral to axon conduction block, indicating crossed spinal phrenic motor facilitation (csPMF). csPMF was independent of spinal TNFα and aPKC. Ipsilateral iPMF and csPMF following unilateral withdrawal of phrenic synaptic inputs were associated with proportional increases in phrenic responses to chemoreceptor stimulation (hypercapnia), suggesting iPMF and csPMF increase phrenic dynamic range. These data suggest that local, spinal mechanisms sense and respond to reduced synaptic inputs to phrenic motor neurons. We hypothesize that iPMF and csPMF may represent compensatory mechanisms that assure adequate motor output is maintained in a physiological system in which prolonged inactivity ends life.

Putative roles of neuropeptides in vagal afferent signaling

The vagus nerve is a major pathway by which information is communicated between the brain and peripheral organs. Sensory neurons of the vagus are located in the nodose ganglia. These vagal afferent neurons innervate the heart, the lung and the gastrointestinal tract, and convey information about peripheral signals to the brain important in the control of cardiovascular tone, respiratory tone, and satiation, respectively. Glutamate is thought to be the primary neurotransmitter involved in conveying all of this information to the brain. It remains unclear how a single neurotransmitter can regulate such an extensive list of physiological functions from a wide range of visceral sites. Many neurotransmitters have been identified in vagal afferent neurons and have been suggested to modulate the physiological functions of glutamate. Specifically, the anorectic peptide transmitters, cocaine and amphetamine regulated transcript (CART) and the orexigenic peptide transmitters, melanin concentrating hormone (MCH) are differentially regulated in vagal afferent neurons and have opposing effects on food intake. Using these two peptides as a model, this review will discuss the potential role of peptide transmitters in providing a more precise and refined modulatory control of the broad physiological functions of glutamate, especially in relation to the control of feeding.

A comparison of different mask holds for positive pressure ventilation in a neonatal manikin

BACKGROUND

Ventilation during neonatal resuscitation is typically initiated with a face mask, but may be ineffective due to leak or obstruction.

OBJECTIVE

To compare leak using three methods of mask hold.

METHODS

Medical and nursing staff regularly involved in neonatal resuscitation used the three holds (two-point, two-handed, spider) on a manikin in a random order to apply positive pressure ventilation (PPV) at standard settings each for 1 min while mask leak was recorded.

RESULTS

Participants (n=53) varied in experience (1-23 years) and hand size. Combined median (IQR) leak was 14 (2-46)% and was not different among the holds.

CONCLUSIONS

There was no difference in the leak measured using the three different mask holds.

Heliox for mechanically ventilated newborns with bronchopulmonary dysplasia

OBJECTIVE

We assessed the safety and studied the influence of short-term helium-oxygen (heliox) mechanical ventilation (MV) on respiratory function, gas exchange and oxygenation in infants with bronchopulmonary dysplasia (BPD) or at high risk for BPD.

DESIGN

A pilot, time-series study.

SETTING

Neonatal intensive care unit.

PATIENTS

Infants with severe BPD who required MV.

INTERVENTIONS

MV with helium-oxygen and air-oxygen mixtures.

MAIN OUTCOME MEASURES

Respiratory parameters, acid-base balance, oxygenation and vital signs were recorded at five time points: initially during MV with air-oxygen, after 15 and 60 min of helium-oxygen MV, and 15 and 60 min after return to air-oxygen MV.

RESULTS

15 infants with BPD were enrolled. Helium-oxygen MV was well tolerated and was associated with a statistically significant increase in tidal volume, dynamic compliance and peak expiratory flow rate. An improvement in oxygenation and a decrease in fraction of inspired oxygen was also observed. During helium-oxygen MV there was a significant decrease in the oxygenation index and alveolar-arterial oxygen tension difference. The PaO2/fraction of inspired oxygen (FiO2) ratio increased significantly during helium-oxygen ventilation. A decrease in PaCO2 and an increase in pH were also observed during helium-oxygen administration, however this was not statistically significant. After ventilation with helium-oxygen was discontinued, the infants' respiratory function and oxygenation deteriorated and supplemental oxygen requirements increased accordingly.

CONCLUSIONS

Helium-oxygen MV is safe and resulted in improvement of respiratory function and oxygenation in infants with severe BPD requiring MV.

Diagnosis of cystic fibrosis in London and South East England before and after the introduction of newborn screening

INTRODUCTION

Newborn screening (NBS) for cystic fibrosis (CF) was introduced to London and South East England in 2007. We wished to assess the details of missed cases, and to compare the age at diagnosis and other clinical parameters, prescreening and postscreening.

METHODS

Retrospective and prospective case notes and database review of all newly diagnosed CF patients in our 7 CF centres, for 18 months before and 4 years after NBS started.

RESULTS

347 patients were diagnosed with CF. 126 patients were not screened (born before or abroad), and had a median age at diagnosis of 2.4 years, excluding those with meconium ileus (MI). Their median time to diagnosis from initial symptoms was 1 year, and in 10% it was >6 years. After NBS started, 170 were diagnosed by NBS (48% were already symptomatic); 7 moved into the region after NBS elsewhere; 34 presented with MI (6 were negative on NBS); and 10 screened children were missed (false negative cases). Median age of diagnosis was 3 weeks. Prevalence was 1 in 3991 live births. By 2 years of age (with data on 104 patients), 49 children (47%) had their first isolation of Pseudomonas aeruginosa, while 37 (36%) had their first growth of Staphylococcus aureus from respiratory cultures.

CONCLUSIONS

NBS has significantly reduced the age of diagnosis, although many were symptomatic even at 3 weeks of age. A small number of patients with CF can still be missed by the screening programme, and the diagnosis should be considered even with a negative screen result.

Patient comfort during treatment with heated humidified high flow nasal cannulae versus nasal continuous positive airway pressure: a randomised cross-over trial

OBJECTIVE

To compare patient comfort in preterm infants treated with heated humidified high flow nasal cannulae (HHHFNC) versus nasal continuous positive airway pressure (NCPAP).

DESIGN

Randomised cross-over trial (2×24 h).

SETTING

Single tertiary neonatal unit.

PATIENTS

20 infants less than 34 weeks postmenstrual age treated with NCPAP due to mild respiratory illness.

INTERVENTIONS

After parental consent, infants were randomised to 24 h of treatment with NCPAP or HHHFNC followed by 24 h of the alternate therapy.

MAIN OUTCOME MEASURES

Primary outcome was patient comfort assessed by the EDIN (neonatal pain and discomfort) scale. Secondary outcomes were respiratory parameters (respiratory rate, FiO2, SpO2, TcPCO2), ambient noise, salivary cortisol and parental assessments of their child.

RESULTS

We found no differences between HHHFNC and NCPAP in mean cumulative EDIN score (10.7 vs 11.1, p=0.25) or ambient noise (70 vs 74 dBa, p=0.18). Parents assessed HHHFNC treatment as significantly better in the three domains, 1) child satisfied, 2) parental contact and interaction and 3) possibility to take part in care. Mean respiratory rate over 24 h was lower during HHHFNC than CPAP (41 vs 46, p=0.001). Other respiratory parameters were similar.

CONCLUSIONS

Using EDIN scale, we found no difference in patient comfort with HHHFNC versus NCPAP. However, parents preferred HHHFNC, and during HHHFNC respiratory rate was lower than during NCPAP.

CLINICALTRIALSGOV, NUMBER

NCT01526226.

Definitions of extubation success in very premature infants: a systematic review

OBJECTIVE

Studies of extubation in preterm infants often define extubation success as a lack of reintubation within a specified time window. However, the duration of observation that defines extubation success in preterm infants has not been validated. The purpose of this study was to systematically review published definitions of extubation success in very preterm infants and to analyse the effect of the definition of extubation success on the reported rates of reintubation.

DESIGN

Studies including very preterm infants published between 1 January 2002 and 30 June 2012 that reported reintubation as an outcome were reviewed for definitions of extubation success. Stepwise multivariable linear regression was used to explore variables associated with rate of reintubation.

RESULTS

Two independent reviewers performed the search with excellent agreement (κ=0.93). Of the 44 eligible studies, 31 defined a window of observation that ranged from 12 to 168 h (7 days). Extubation and reintubation criteria were highly variable. The mean±SD reintubation rate across all studies was 25±9%. In studies of infants with median birth weight (BW) ≤1000 g, reintubation rates steadily increased as the window of observation increased, without apparent plateau (p = 0.001). This trend was not observed in studies of larger infants (p = 0.85).

CONCLUSIONS

Variability in the reported definitions of extubation success makes it difficult to compare extubation strategies across studies. The appropriate window of observation following extubation may depend on the population. In infants with BW ≤1000 g, even a week of observation may fail to identify some who will require reintubation.

Increased vocal intensity due to the Lombard effect in speakers with Parkinson's disease: simultaneous laryngeal and respiratory strategies

PURPOSE

The objective of the present study was to investigate whether speakers with hypophonia, secondary to Parkinson's disease (PD), would increases their vocal intensity when speaking in a noisy environment (Lombard effect). The other objective was to examine the underlying laryngeal and respiratory strategies used to increase vocal intensity.

METHODS

Thirty-three participants with PD were included for study. Each participant was fitted with the SpeechVive™ device that played multi-talker babble noise into one ear during speech. Using acoustic, aerodynamic and respiratory kinematic techniques, the simultaneous laryngeal and respiratory mechanisms used to regulate vocal intensity were examined.

RESULTS

Significant group results showed that most speakers with PD (26/33) were successful at increasing their vocal intensity when speaking in the condition of multi-talker babble noise. They were able to support their increased vocal intensity and subglottal pressure with combined strategies from both the laryngeal and respiratory mechanisms. Individual speaker analysis indicated that the particular laryngeal and respiratory interactions differed among speakers.

CONCLUSIONS

The SpeechVive™ device elicited higher vocal intensities from patients with PD. Speakers used different combinations of laryngeal and respiratory physiologic mechanisms to increase vocal intensity, thus suggesting that disease process does not uniformly affect the speech subsystems.

LEARNING OUTCOMES

Readers will be able to: (1) identify speech characteristics of people with Parkinson's disease (PD), (2) identify typical respiratory strategies for increasing sound pressure level (SPL), (3) identify typical laryngeal strategies for increasing SPL, (4) define the Lombard effect.

IQ Scores of Children with Moderate Asthma: A Comparison with Healthy Children

OBJECTIVE

Intelligence quotient is an indicator of one's efficacy and many factors including chronic diseases may impact upon it. This study aims to compare the IQ of children diagnosed with moderate asthma to the IQ of healthy children.

METHODS

This comparative study was conducted between June 2011 and January 2012 in an Academic Referral Clinic. In this study, 114 patients aged 6 to 13 years who were diagnosed with moderate asthma were compared with 90 age and sex matched healthy patients from their families. Wechsler intelligence scale for children was used by split half method to calculate the overall IQ, verbal IQ and practical IQ. The t-test and Chi square test were used to analyze quantitative variables and qualitative variables, respectively.

RESULTS

In this study, 204 children, 114 (56%) in the case group and 90 children (44%) in the control group participated in comparing their IQs. One hundred and fifteen (56%) were males and 89 (44%) were females. The overall IQs of asthmatic patients and healthy patients were 109 and 108, respectively; the difference was not significant (p=0.905). Furthermore, there was no significant difference in the IQ scores between males and females.

CONCLUSION

Although asthma is a chronic disease and causes many respiratory problems, it has no negative impact on IQ.

Fifteen-minute consultation: The infant with frequent infections

Children with frequent or recurrent infections commonly present to medical practitioners in both primary and secondary care. Here we provide a structured approach to the consultation of the infant under 2 years of age with frequent infections. The key is a focused history and examination to elicit red flags to an underlying diagnosis, while at the same time seeking benign explanations for the frequency of infections, which account for the majority of children, thereby avoiding unnecessary investigations.

Desert dust and human health disorders

Dust storms may originate in many of the world's drylands and have an effect not only on human health in the drylands themselves but also in downwind environments, including some major urban centres, such as Phoenix, Kano, Athens, Madrid, Dubai, Jedda, Tehran, Jaipur, Beijing, Shanghai, Seoul, Taipei, Tokyo, Sydney, Brisbane and Melbourne. In some parts of the world dust storms occur frequently throughout the year. They can transport particulate material, pollutants, and potential allergens over thousands of km from source. The main sources include the Sahara, central and eastern Asia, the Middle East, and parts of the western USA. In some parts of the world, though not all, the frequency of dust storms is changing in response to land use and climatic changes, and in such locations the health implications may become more severe. Data on the PM10 and P2.5 loadings of dust events are discussed, as are various pollutants (heavy metals, pesticides, etc.) and biological components (spores, fungi, bacteria, etc.). Particulate loadings can far exceed healthy levels. Among the human health effects of dust storms are respiratory disorders (including asthma, tracheitis, pneumonia, allergic rhinitis and silicosis) cardiovascular disorders (including stroke), conjunctivitis, skin irritations, meningococcal meningitis, valley fever, diseases associated with toxic algal blooms and mortality and injuries related to transport accidents.

Risk assessment for cardiovascular and respiratory mortality due to air pollution and synoptic meteorology in 10 Canadian cities

Synoptic weather and ambient air quality synergistically influence human health. We report the relative risk of mortality from all non-accidental, respiratory-, and cardiovascular-related causes, associated with exposure to four air pollutants, by weather type and season, in 10 major Canadian cities for 1981 through 1999. We conducted this multi-city time-series study using Poisson generalized linear models stratified by season and each of six distinctive synoptic weather types. Statistically significant relationships of mortality due to short-term exposure to carbon monoxide, nitrogen dioxide, sulphur dioxide, and ozone were found, with significant modifications of risk by weather type, season, and mortality cause. In total, 61% of the respiratory-related mortality relative risk estimates were significantly higher than for cardiovascular-related mortality. The combined effect of weather and air pollution is greatest when tropical-type weather is present in the spring or summer.

Prevalence of Acanthamoeba spp. in Tasmanian intensive care clinical specimens

BACKGROUND

Acanthamoebae are ubiquitous free-living environmental amoebae that may occasionally cause keratitis, granulomatous encephalitis, cutaneous lesions and systemic disease in humans. Acanthamoeba spp. have been implicated as a vehicle by which a number of common bacterial causes of healthcare-associated pneumonia may enter the lungs. Limited evidence has been found implicating Acanthamoeba spp. as a primary cause of pneumonia and urinary catheter colonization in intensive care patients.

AIM

To explore the possibility of colonization of the respiratory and urinary tracts of intensive care patients with free-living amoebae.

METHODS

Thirty-nine catheter urines, 50 endotracheal trap sputa and one general ward sputum sample from 45 patients and nine intensive care unit (ICU) environmental water samples were collected during a four-and-half-month period in the Royal Hobart Hospital from August 2011.

FINDINGS

Acanthamoebae were isolated by culture and detected by polymerase chain reaction in two sputum samples from a single patient, taken one week apart. A single Acanthamoeba species isolate was detected by culture only from the ICU environment.

CONCLUSION

Colonization of ICU patients' respiratory tracts with Acanthamoeba spp. does occur. This may have significance for the role of acanthamoebae as a source of bacterial pathogens in intensive therapy patients' respiratory tracts.

Emergency department surveillance as a proxy for the prediction of circulating respiratory viral disease in Eastern Ontario

BACKGROUND

Seasonal outbreaks of winter respiratory viruses are responsible for increases in morbidity and mortality in the community. Previous studies have used hospitalizations, intensive care unit and emergency department (ED) visits as indicators of seasonal influenza incidence.

OBJECTIVES

To evaluate whether ED visits can be used as a proxy to detect respiratory viral disease outbreaks, as measured by laboratory confirmation.

METHODS

An Emergency Department Syndromic Surveillance system was used to collect ED chief complaints in Eastern Ontario from 2006 to 2010. Comparable laboratory-confirmed cases of respiratory viral infections were collected from the Public Health Ontario Laboratory in Kingston, Ontario. Correlations between ED visits and laboratory-confirmed cases were calculated.

RESULTS

Laboratory-confirmed cases of selected respiratory viruses were significantly correlated with ED visits for respiratory and fever/influenza-like illness. In particular, respiratory syncytial virus (Spearman's rho = 0.593), rhinovirus (Spearman's rho = 0.280), influenza A (Spearman's rho = 0.528), influenza B (Spearman's rho = 0.426) and pH1N1 (Spearman's rho = 0.470) increased laboratory test levels were correlated with increased volume of ED visits across a number of age demographics. For the entire study population and all studied viruses, the Spearman's rho was 0.702, suggesting a strong correlation with ED visits. Laboratory-confirmed cases lagged in reporting by between one and two weeks for influenza A and pH1N1 compared with ED visit volume.

CONCLUSION

These findings support the use of an Emergency Department Syndromic Surveillance system to track the incidence of respiratory viral disease in the community. These methods are efficient and can be performed using automated electronic data entry versus the inherent delays in the primary care sentinel surveillance system, and can aid the timely implementation of preventive and preparatory health interventions.

Evaluation of the persistence of functional and biological respiratory health effects in clean-up workers 6 years after the prestige oil spill

Fishermen who had participated in clean-up activities of the Prestige oil spill showed increased bronchial responsiveness and higher levels of respiratory biomarkers 2 years later. We aimed to evaluate the persistence of these functional and biological respiratory health effects 6 years after clean-up work. In 2008/2009 a follow-up study was done in 230 never-smoking fishermen who had been exposed to clean-up work in 2002/2003 and 87 non-exposed fishermen. Lung function and bronchial responsiveness testing and the determination of respiratory biomarkers in exhaled breath condensate were done identically as in the baseline survey in 2004/2005. Associations between participation in clean-up work and respiratory health parameters were assessed using linear and logistic regression analyses adjusting for sex and age. Information from 158 exposed (69%) and 57 non-exposed (66%) fishermen was obtained. Loss to follow-up in the non-exposed was characterised by less respiratory symptoms at baseline. During the 4-year follow-up period lung function, bronchial hyperresponsiveness and the levels of respiratory biomarkers of oxidative stress and growth factors had deteriorated notably more among non-exposed than among exposed. At follow-up, respiratory health indices were similar or better in clean-up workers than in non-exposed. No clear differences between highly exposed and moderately exposed clean-up workers were found. In conclusion, we could not detect long-term respiratory health effects in clean-up workers 6 years after the Prestige oil spill. Methodological issues that need to be considered in this type of studies include the choice of a non-exposed control group and limitation of follow-up to subgroups such as never smokers.

Development of an inhalation unit risk factor for hexavalent chromium

A unit risk factor (URF) was developed for hexavalent chromium (CrVI). The URF is based on excess lung cancer mortality in two key epidemiological studies of chromate production workers. The Crump et al. (2003) study concerns the Painesville, OH worker cohort, while Gibb et al. (2000) regards the Baltimore, MD cohort. A supporting assessment was also performed for a cohort from four low-dose chromate plants (Leverkusen and Uerdingen, Germany, Corpus Christi, TX, Castle Hayne, NC). For the Crump et al. (2003) study, grouped observed and expected number of lung cancer mortalities along with cumulative CrVI exposures were used to obtain the maximum likelihood estimate and asymptotic variance of the slope (β) for the linear multiplicative relative risk model using Poisson regression modeling. For the Gibb et al. (2000) study, Cox proportional hazards modeling was performed with optimal exposure lag and adjusting for the effect of covariates (e.g., smoking) to estimate β values. Life-table analyses were used to develop URFs for each of the two key studies, as well as for supporting and related studies. The two key study URFs were combined using weighting factors relevant to confidence to derive the final URF for CrVI of 2.3E-03 per μgCrVI/m(3).