Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

798 SPOT DELIRIUM - IMPROVING DELIRIUM AWARENESS AND ASSESSMENT USING ELECTRONIC 4AT

Introduction

Delirium is a common medical emergency which is associated with adverse outcomes but often unrecognised in up to two thirds of patients in the acute care setting. The 4AT is a sensitive and rapid assessment tool that can be applied to assess for delirium in clinical practice.

Method

An initial audit into the use of delirium diagnostic assessment scores on an Acute Medical Assessment Unit (AAU) was carried out. Medical notes were reviewed of patients over 75 years (n = 42) admitted over a 6 week period. A re-audit was undertaken following an educational induction session for junior doctors about delirium and 4AT (n = 42).

Results

Initially 14% of patients with documented acute confusion (n = 2) had a 4AT assessment completed. 2 patients were recognised to be at risk of delirium but did not have a 4AT. A diagnosis of dementia was documented for 28% (n = 12) of patients however only one had a 4AT. An educational session about delirium and how to complete the electronic 4AT assessment was organised for junior doctors on AAU. Before teaching, survey results showed no participants were familiar with the 4AT screening tool. Following the session all participants indicated knowing where to locate the electronic 4AT and reported improved confidence in recognising delirium. On re-audit 14 patients had documented confusion but 4AT assessment completion increased to 79%. For those identified as being at risk of delirium or having previous delirium 90% had a 4AT completed. All patients with a dementia had an AMTS and 89% also had a 4AT.

Conclusion

There was an improvement in documentation of both 4AT and AMTS forms following engagement in education and use of an electronic assessment tool to diagnose delirium. Future recommendations include interdisciplinary induction sessions to target a wider audience to improve awareness and recognition of delirium in acute care.

Review: immunosuppression for the lung transplant patient

Lung transplantation (LTx) has evolved significantly since its inception and the improvement in LTx outcomes over the last three decades has predominantly been driven by advances in immunosuppression management. Despite the lack of new classes of immunosuppression medications, immunosuppressive strategies have evolved significantly from a universal method to a more targeted approach, reflecting a greater understanding of the need for individualized therapy and careful consideration of all factors that are influenced by immunosuppression choice. This has become increasingly important as the demographics of lung transplant recipients have changed over time, with older and more medically complex candidates being accepted and undergoing LTx. Furthermore, improved survival post lung transplant has translated into more immunosuppression related comorbidities long-term, predominantly chronic kidney disease (CKD) and malignancy, which has required further nuanced management approaches. This review provides an update on current traditional lung transplant immunosuppression strategies, with modifications based on pre-existing recipient factors and comorbidities, peri-operative challenges and long term complications, balanced against the perpetual challenge of chronic lung allograft dysfunction (CLAD). As we continue to explore and understand the complexity of LTx immunology and the interplay of different factors, immunosuppression strategies will require ongoing critical evaluation and personalization in order to continue to improve lung transplant outcomes.

Systematic review and meta-analysis of tracheostomy outcomes in COVID-19 patients

A systematic review and meta-analysis of the entire COVID-19 Tracheostomy cohort was conducted to determine the cumulative incidence of complications, mortality, time to decannulation and ventilatory weaning. Outcomes of surgical versus percutaneous and outcomes relative to tracheostomy timing were also analysed. Studies reporting outcome data on patients with COVID-19 undergoing tracheostomy were identified and screened by 2 independent reviewers. Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines were followed. Outcome data were analysed using a random-effects model. From 1016 unique studies, 39 articles reporting outcomes for a total of 3929 patients were included for meta-analysis. Weighted mean follow-up time was 42.03±26 days post-tracheostomy. Meta-analysis showed that 61.2% of patients were weaned from mechanical ventilation [95%CI 52.6%-69.5%], 44.2% of patients were decannulated [95%CI 33.96%-54.67%], and cumulative mortality was found to be 19.23% [95%CI 15.2%-23.6%] across the entire tracheostomy cohort. The cumulative incidence of complications was 14.24% [95%CI 9.6%-19.6%], with bleeding accounting for 52% of all complications. No difference was found in incidence of mortality (RR1.96; p=0.34), decannulation (RR1.35, p=0.27), complications (RR0.75, p=0.09) and time to decannulation (SMD 0.46, p=0.68) between percutaneous and surgical tracheostomy. Moreover, no difference was found in mortality (RR1.57, p=0.43) between early and late tracheostomy, and timing of tracheostomy did not predict time to decannulation. Ten confirmed nosocomial staff infections were reported from 1398 tracheostomies. This study provides an overview of outcomes of tracheostomy in COVID-19 patients, and contributes to our understanding of tracheostomy decisions in this patient cohort.

Head and neck sarcoma: three-year data from a tertiary referral centre

INTRODUCTION

Sarcomas of the head and neck are neoplasms arising from the embryonic mesenchyme. They are rare and heterogeneous in nature and are associated with significant morbidity and mortality. This study evaluates patients referred to the Oxford Sarcoma Service, a tertiary referral centre.

METHODS

Patients discussed over a three-year period were included. Medical records were analysed using the electronic patient record database. Data were acquired on a range of domains, including: demographics, histopathology, treatment modality, recurrence, mortality, survival, etc.

RESULTS

Thirty-two eligible patients, 21 male and 11 female, were identified with a mean age of 58 years; 26 out of 32 patients had high-grade sarcomas. The commonest histological subtype was chondrosarcoma (8/32). Twenty-two underwent planned multidisciplinary team surgical resection after biopsy and staging: negative margins were noted in 9, with close and involved margins in 5 and 8, respectively. Local recurrence was noted in 13 and 6 had metastatic disease out of the 32 eligible patients. Mortality was noted in 10 out of 32 patients. Mean survival was 69.5 months. Five-year overall survival was 64%. Surgery demonstrated statistically significant improvement in survival (p=0.0095). There were no significant differences in survival, recurrence or marginal status between methods of adjuvant or neoadjuvant therapy.

CONCLUSION

Outcomes of head and neck sarcomas are inferior compared with other types of sarcoma. The nature of the complex surrounding anatomy presents unique challenges in surgical management. This in turn affects rates of local recurrence and prognosis. Therefore, it is critical that they are managed in tertiary, specialist centres with a multidisciplinary approach.

HIV and Solid Organ Transplantation: A 15-Year Retrospective Audit at a Tertiary Australian Transplant Centre

BACKGROUND

The incidence of end-stage organ disease in people living with HIV (PLWH) is increasing, as people live longer due to potent, tolerable antiretroviral therapy. Consequently, the number of PLWH who would benefit from solid organ transplant (SOT) is rising. Solid organ transplantation experience in PLWH in Australia remains limited. The aim of this study was to retrospectively review the outcomes for SOT in PLWH in Victoria, Australia.

METHODS

A retrospective cohort study of PLWH undergoing SOT over a 15-year period was performed. Adult PLWH over 18 years of age were eligible and identified from the Victorian HIV Service database. Descriptive statistics were used to summarise baseline demographics and clinical data, and outcomes following SOT.

RESULTS

Nine virologically-suppressed PLWH underwent SOT from HIV-negative donors; 5 kidneys, 2 livers, and 2 bilateral sequential lung transplants. All patients were male, with a median age of 57.3 years (IQR 54.3-60.1), CD4 count of 485 (IQR 342-835) at transplantation, and comorbidities were common at baseline. After a median follow up of 3.9 years (IQR 2.7-7.6), 8 (89%) patents were alive, 7 (78%) had functioning grafts, though 5 (56%) experienced organ rejection. Infections were common. Two patients required modification to their antiretroviral therapy due to significant drug-drug interactions, prior to transplant, while 5 (56%) had modifications post-SOT. No patients experienced HIV virologic failure.

CONCLUSION

PLWH with end-stage organ disease experience good clinical and functional outcomes, and should be considered for SOT where indicated. However, multidisciplinary planning and care is essential to optomise care in this patient group. This article is protected by copyright. All rights reserved.

An update on chronic lung allograft dysfunction

Chronic lung allograft dysfunction (CLAD) remains a significant challenge and the major determinant of morbidity and mortality post lung transplantation (LTx). The definition of CLAD has evolved significantly over the last ten years, reflecting better understanding of pathophysiology and different phenotypes. While there is an agreed consensus approach to CLAD, questions remain regarding the limitations of lung function parameters as well as the role of imaging and histopathology. Here we present a current snapshot of the definition of CLAD, its evolution and future directions.

The presentation, clinical features, complications, and treatment of congenital dacryocystocele

PurposeTo determine the incidence and presenting features of congenital dacryocystocele in the United Kingdom. To report on those cases complicated by dacryocystitis, respiratory compromise, and the treatment undertaken.MethodsA prospective observational study of cases of congenital dacryocystocele presenting in the United Kingdom between September 2014 and October 2015. Infants <3 months of age presenting with a cystic swelling in the medial canthal area were included. Cases were identified via the British Ophthalmology Surveillance Unit (BOSU) reporting system.ResultsA total of 49 cases were reported during the study period. This gives an incidence of 1 in 18 597 live births. There was a 71% response rate to the questionnaire. The average age at presentation was 16.94 days. Dacryocystoceles were unilateral in 91% of cases. Dacryocystitis was a complicating factor in 49% of patients and 17% had respiratory distress. Uncomplicated dacryocystocele responded well to conservative measures in 86%. Surgical intervention was required in 23% of patients. Those cases complicated by dacryocystitis (29%) and nasal obstruction (17%) were more likely to require surgical intervention compared to those with dacryocystocele alone (14%). Digital massage appears to reduce the likelihood of requiring surgical intervention. The mean time to resolution was 19 days.ConclusionsCongenital dacryocystocele is a rare presentation in the United Kingdom. Dacryocystitis and respiratory compromise commonly complicate a dacryocystocele. The use of digital massage as an early intervention is advocated and conservative measures may be sufficient in cases of uncomplicated dacryocystocele.

A successful aggressive surgical and medical approach to pulmonary artery obstruction due to Mycobacterium abscessus infection post lung transplantation

Mycobacterium abscessus infection following lung transplantation has historically been associated with poor outcomes. We report a case of bilateral lung retransplantation complicated by obstruction of the right pulmonary artery secondary to M. abscessus mycotic aneurysm. Aggressive surgical management, including reconstruction of the right pulmonary artery, was undertaken with prolonged antimicrobial therapy. Thirty-six months later, antibiotics have been discontinued and the patient has stable soft tissue chest wall disease with good graft function. Mortality and morbidity associated with M. abscessus infection is considerable but this case illustrates that with aggressive early management, outcomes may be favorable.

Domiciliary non-invasive ventilation post lung transplantation

BACKGROUND AND OBJECTIVE

The benefits of domiciliary non-invasive ventilation (NIV) post lung transplantation (LTx) have not previously been described. This was a single-centre retrospective audit of patients requiring domiciliary NIV post-LTx. Our aim was to describe indications for NIV and outcomes in chronic lung allograft dysfunction (CLAD) and diaphragmatic palsy.

METHODS

All patients requiring domiciliary NIV post-LTx between 2010 and June 2016 were assessed. NIV indications, respiratory function and patient outcomes were collected.

RESULTS

Out of 488 LTx recipients, 20 patients were identified as requiring NIV over the 6.5-year study period. The most common indications for NIV were CLAD and diaphragmatic palsy. Hypercapnia improved significantly with NIV. Patient outcomes were poor with nine (45%) patients dying, four (20%) undergoing redo-LTx, four (20%) continuing domiciliary NIV and only three (15%) patients weaned off NIV.

CONCLUSION

This is the first case series to describe the use of domiciliary NIV post-LTx. Patients commenced on NIV post-LTx had severely impaired lung function and severe hypercapnia. Patients with diaphragmatic palsy often recovered. The mortality rate was high in chronic allograft dysfunction.

A multicentre audit of GDPs knowledge of orthodontic retention

OBJECTIVE

To determine GDP knowledge and willingness to supervise orthodontic retention and provide replacements retainers.

DESIGN

An audit sampling GDPs from six centres within England (Bradford, Cambridge, Burton-Upon-Trent, Croyden, Norwich and Plymouth). A gold standard of 100% of GDPs should be aware of commonly used retainers and be able to provide replacements was selected.

METHOD

Overall, 1,053 postal questionnaires were sent to local GDPs. The questions covered knowledge and provision of various retainers, practitioner background and education. GDP satisfaction with the information provided by the orthodontist at discharge was also explored.

RESULTS

Five hundred and two questionnaires were received (response rate of 48%). The majority of GDPs (64%) were trained in the UK. Awareness of vacuum-formed, Hawley and fixed retainers was generally high. A significantly smaller number of GDPs were willing to prescribe, fit or review the retainers. The most common reasons for reluctance in provision were insufficient knowledge, financial and time constraints. Over two thirds (72%) of GDPs would like further training on retention.

CONCLUSION

This audit highlights a need for increased training at undergraduate and postgraduate levels to update practitioners about contemporary retention practice. Better communication is required from orthodontists to GDPs to ensure that on discharge the dentist is aware of the retainer type and retention regime.

How can we improve the quality of transplantable lungs?

INTRODUCTION

Optimization of lungs for organ donation is becoming increasingly important as donation rates stagnate despite growing waiting lists. Improving procurement and utilization of donated lungs has the ability to reduce mortality and time on the lung transplantation (LTx) waiting list. Additionally, assessment and optimization of donor lungs can reduce both early and late post-LTx morbidity and mortality, as well as reduce overall costs and resource utility. Areas covered: Strategies that we will discuss in detail include intensive care management practices, such as targeted ventilation protocols and therapeutic bronchoscopy, as well as the ever expanding possibilities within the arena of ex vivo lung perfusion (EVLP). Expert commentary: Donor lung quality is currently optimized both in vivo prior to organ procurement, and also via EVLP circuits. Despite good evidence demonstrating the utility of both approaches, data remain elusive as to whether EVLP is beneficial for all donor lungs prior to implantation, or instead as a tool by which we can evaluate and recondition sub-optimal donor lungs.

ABO incompatible renal transplantation following lung transplantation

We present management strategies utilised for the first case of an urgent live-donor ABO incompatible B blood group renal transplant, in a patient with a prior A blood group lung transplant for cystic fibrosis. Three years on, renal function is excellent and stable, whilst lung function has improved.

Evolving practice: X-linked agammaglobulinemia and lung transplantation

X-linked agammaglobulinemia (XLA) is a rare primary humoral immunodeficiency syndrome characterized by agammaglobulinemia, recurrent infections and bronchiectasis. Despite the association with end-stage bronchiectasis, the literature on XLA and lung transplantation is extremely limited. We report a series of 6 XLA patients with bronchiectasis who underwent lung transplantation. Short-term outcomes were excellent however long-term outcomes were disappointing with a high incidence of pulmonary sepsis and chronic lung allograft dysfunction (CLAD).

Coeliac disease is more common in children with high socio-economic status

AIM

There are a number of genetic and environmental factors that are associated with an increased risk of developing coeliac disease. Our aim was to determine whether socio-economic deprivation increases or reduces the development of the disease.

METHODS

A cross-sectional study identified all children <16 years old diagnosed with coeliac disease in the same tertiary paediatric centre between January 1995 and December 2011. Data, including age at diagnosis and postcode, were collected and linked with the quintile rank of the Welsh Index of Multiple Deprivation score 2008, a measure of socio-economic status.

RESULTS

We included 232 patients and identified a graded association between the prevalence of coeliac disease and socio-economic deprivation, which showed a higher rate in children living in more affluent areas. The largest difference was between the lowest deprivation level (rate/1000 = 1.16) and the highest deprivation level (rate/1000 = 0.49).

CONCLUSION

In our population, coeliac disease was more common in children in the higher socio-economic groupings. The reasons for this are not clear, but perhaps both the 'hygiene hypothesis' and the health seeking behaviours of parents with high socio-economic status are possible factors in the more frequent diagnosis of coeliac disease in this group.

Electromagnetic inductance plethysmography to measure tidal breathing in preterm and term infants

Tidal breathing measurements which provide a non-invasive measure of lung function in preterm and term infants are particularly useful to guide respiratory support. We used a new technique of electromagnetic inductance plethysmography (EIP) to measure tidal breathing in infants between 32 and 42 weeks postconceptional age (PCA). Tidal breathing was measured in 49 healthy spontaneously breathing infants between 32 and 42 weeks PCA. The weight-corrected tidal volume (V(T) ) and minute volume (MV) decreased with advancing PCA (V(T) 6.5 ± 1.5 ml/kg and MV 0.44 ± 0.04 L/kg/min at 32-33 weeks, respectively; 6.3 ± 0.9 ml/kg and 0.38 ± 0.02 L/kg/min at 34-36 weeks; and 5.1 ± 1.1 ml/kg and 0.28 ± 0.02 L/kg/min at term, V(T) P < 0.001 and MV P < 0.01 for 32-33 weeks PCA vs. term; V(T) P = 0.016 and MV P = 0.015 for 34-36 weeks PCA vs. term). Respiratory frequency and the phase angle decreased significantly with advancing PCA but the flow parameter t(PTEF) /t(E) did not change significantly. Using a new technique to measure tidal breathing parameters in newborn infants, our data confirms its usability in clinical practice and establishes normative data which can guide future respiratory management of newborn infants.

Ca2+ activation of cytosolic calpain induces the transition from apoptosis to necrosis in neutrophils with externalized phosphatidylserine

Physiologically, apoptotic neutrophils are ingested before they undergo necrosis. However, failure of ingestion will lead to necrosis of neutrophils and the unregulated release of neutrophil-derived pathogenic molecules, such as protease and hydrolases. Understanding the mechanism of postapoptotic necrosis is thus clearly important. Here, we monitored the apoptotic-to-necrotic transition in individual-aged human neutrophils in vitro by imaging fluorescent probes for externalized PS, cytosolic Ca(2+), and membrane integrity. This showed that prenecrotic-aged neutrophils with externalized PS had a significantly elevated cytosolic-free Ca(2+) level. A further unregulated Ca(2+) influx into PS-externalized neutrophils always preceded the necrotic transition. Ca(2+) elevation was not simply a consequence of aging, as PS externalization was not uniform in similarly aged neutrophil populations. PS-externalized neutrophils could be induced to undergo necrosis experimentally by simply elevating cytosolic Ca(2+) further with ionomycin. This effect was observed only in neutrophils that had externalized PS, and was independent of the time after their isolation from blood (i.e., in vitro age). As pharmacological inhibition of calpain-1 inhibition significantly reduced this CAIN, it was concluded that the apoptotic-to-necrotic transition was a consequence of uncontrolled calpain activation that resulted from Ca(2+) overload in PS-externalized neutrophils.

Estimation of tidal ventilation in preterm and term newborn infants using electromagnetic inductance plethysmography

Tidal volume (VT) measurements in newborn infants remain largely a research tool. Tidal ventilation and breathing pattern were measured using a new device, FloRight, which uses electromagnetic inductive plethysmography,and compared simultaneously with pneumotachography in 43 infants either receiving no respiratory support or continuous positive airway pressure (CPAP).Twenty-three infants were receiving CPAP (gestational age 28 ± 2 weeks, mean ± SD) and 20 were breathing spontaneously (gestational age 34 ± 4 weeks). The two methods were in reasonable agreement, with VT (r2 = 0.69) ranging from 5 to 23 ml (4–11 ml kg−1) with a mean difference of 0.4 ml and limit of agreement of −4.7 to + 5.5 ml. For respiratory rate, minute ventilation,peak flow and breathing pattern indices, the mean difference between the two methods ranged between 0.7% and 5.8%. The facemask increased the respiratory rate (P < 0.001) in both groups with the change in VT being more pronounced in the infants receiving no respiratory support. Thus, FloRight provides an easy to use technique to measure term and preterm infants in the clinical environment without altering the infant's breathing pattern.

Congenital diaphragmatic hernia

Infants with congenital diaphragmatic hernia (CDH) have significant mortality and long-term morbidity. Only 60-70% survive and usually those in high-volume centres. The current Task Force, therefore, has convened experts to evaluate the current literature and make recommendations on both the antenatal and post-natal management of CDH. The incidence of CDH varies from 1.7 to 5.7 per 10,000 live-born infants depending on the study population. Antenatal ultrasound scanning is routine and increasingly complemented by the use of magnetic resonance imaging. For isolated CDH, antenatal interventions should be considered, but the techniques need vigorous evaluation. After birth, management protocols are often used and have improved outcome in nonrandomised studies, but immediate intubation at birth and gentle ventilation are important. Pulmonary hypertension is common and its optimal management is crucial as its severity predicts the outcome. Usually, surgery is delayed to allow optimal medical stabilisation. The role of minimal invasive post-natal surgery remains to be further defined. There are differences in opinion about whether extracorporeal membrane oxygenation improves outcome. Survivors of CDH can have a high incidence of comorbidities; thus, multidisciplinary follow-up is recommended. Multicentre international trials are necessary to optimise the antenatal and post-natal management of CDH patients.

Long-term outcomes from bronchoscopic lung volume reduction using a bronchial prosthesis

BACKGROUND AND OBJECTIVE

We evaluated long-term safety and lung function outcomes in a cohort of patients with severe upper-zone heterogeneous emphysema who underwent bronchoscopic lung volume reduction (BLVR) performed with the Emphasys one-way valve.

METHODS

A retrospective cohort study was undertaken to assess long-term outcomes in 23 consecutive patients who underwent upper lobe BLVR between July 2001 and November 2003 as part of a first-in-humans study. Long-term follow up (>12 months) was available in 16/23 patients (median duration of follow up 64 months (range 15-90 months)). Both unilateral (n=4) and bilateral (n=12) BLVR procedures were performed with a mean of 6 (range 3-11) valves being inserted. Changes in pulmonary function tests were assessed longitudinally following the procedure.

RESULTS

13/16 and 11/16 patients showed post-procedure improvements in FEV1 and DL(CO) , respectively. However, early improvements in pulmonary function were not sustained with only 6/16 patients still showing improved lung function at the end of follow up. There were no significant improvements in other indices of pulmonary function. Three patients, in the absence of clinical benefit, proceeded to lung transplantation at 15, 16 and 44 months post BLVR. Four patients died during the course of the study at 27, 29, 39 and 50 months post procedure.

CONCLUSIONS

BLVR with the Emphasys one-way valve has an acceptable safety profile and in select patients may achieve long-term sustained improvements in pulmonary function.

Role of pulmonary infection in the development of chronic lung disease of prematurity

We studied the role of ante- and post-natal infection in the development of chronic lung disease (CLD) of prematurity. 192 newborn infants (61 term and 131 pre-term of <34 weeks gestation: 88 with respiratory distress syndrome, 35 developed CLD and eight died) were recruited. 16S ribosomal RNA (rRNA) genes were identified by PCR of DNA isolated from 840 gastric and lung fluid samples. Ureaplasma spp. were also cultured. Presence of 16S rRNA genes (OR 1.6, 95% CI 1.2-2.2) and Ureaplasma spp. (OR 3.6, 95% CI 1.7-7.7) was significantly associated with the development of CLD. This association remained if the 16S rRNA genes and Ureaplasma spp. were first identified within the first 3 days of life (OR 2.4 (95% CI 1.4-4.1) and 3.8 (95% CI 1.4-10.0), respectively) or if first identified after 3 days of age (OR 1.7 (95% CI 1.1-2.8) and OR 5.1 (95% CI 1.3-19.8), respectively). Peak lung fluid interleukin (IL)-6 and IL-8 were significantly associated with presence of microbes (p<0.0001 and p=0.0001, respectively) and development of CLD (p=0.003 and 0.001, respectively). Both early and late microbial presence in neonatal lung fluid samples was significantly associated with the development of CLD suggesting that both ante- and post-natal infection play a role in the development of CLD.

Paediatrics in Berlin

The aim of this report is to describe the highlights of the European Respiratory Society annual congress in Berlin, Germany. The best abstracts in asthma and allergy, cystic fibrosis, respiratory infection, paediatric and neonatal intensive care, paediatric investigative techniques (in particular respiratory physiology and bronchoscopy) and respiratory epidemiology are presented and set in the context of the current literature.

The viral aetiology of croup and recurrent croup

BACKGROUND

Historically croup was subdivided into classic "viral" croup with associated viral upper respiratory tract infections, and recurrent or spasmodic croup where asthma and allergies were thought more important.

METHODS

All children admitted to the University Hospital of Wales with croup in 2003 were eligible. Baseline demographics including croup score were recorded and per-nasal swabs taken for virus detection by RT-PCR. Recurrent croup was defined as at least one other admission for croup in the preceding or following 3 years.

RESULTS

Sixty (29.4%) children entered the study, and a viral pathogen was detected in 41 (68%). There was no significant difference in the rate of virus detection between those with single episode croup and recurrent croup.

CONCLUSIONS

The aetiologies of viral and recurrent croup appear similar.

Fetal cortisol response to intrauterine microbial colonisation identified by the polymerase chain reaction and fetal inflammation

OBJECTIVE

To determine the fetal cortisol response to intrauterine infection.

STUDY DESIGN

16s ribosomal RNA genes or the urease genes of Ureaplasma spp were identified by the polymerase chain reaction in intrauterine samples. Cord blood cortisol, interleukin 6 (IL6) and IL8 were measured in samples from 31 infants born at <32 weeks gestation.

RESULTS

13 infants (median gestation 30 weeks, birth weight 1350 g) had at least one positive intrauterine sample for microbial genes and 18 infants (31 weeks, 1320 g) did not. The cord blood cortisol concentration was significantly higher in fetuses exposed to intrauterine infection and significantly increased in fetuses/mothers presenting in preterm labour with intact membranes compared with infants delivered by elective prelabour caesarean section (p<0.05). The cord blood cortisol concentration was increased in the mothers with prelabour premature rupture of membranes but this was not significant compared with the caesarean section group. The cord blood cortisol concentration was significantly increased in the presence of chorioamnionitis or funisitis and was moderately correlated with cord blood IL6 (r = 0.64, p<0.01) and IL8 (r = 0.52, p<0.01).

CONCLUSIONS

In this study, cord blood cortisol was increased in the colonised group compared with non-colonised infants. It is unclear if infants born following prelabour premature rupture of the membranes mount an adequate anti-inflammatory response.

Flexible endoscopy of paediatric airways

Paediatric fibreoptic bronchoscopy is used for ever wider indications, and increasingly used in many contexts, including paediatric and neonatal intensive care. The report of this Task Force contains an overview on the current applications of paediatric bronchoscopy. The report discusses the facilities and equipment needed for the procedure, including the newly developed bronchoscopes which are allowing intervention even in very small children. The indications of both flexible and rigid bronchoscopes in the context of newer and smaller flexible endoscopic equipment are also considered. The care of the instruments, including disinfection and sterilisation, is fully documented. Patient management is described, including the relative merits of conscious sedation and general anaesthesia, as well as special settings for the procedure, including the needs in intensive care. Special procedures, increasingly performed bronchoscopically are described. These include bronchoalveolar lavage, endobronchial and transbronchial biopsy, laser therapy, bronchography, and endoscopic intubation and drug therapy. Finally, neonatal bronchoscopy is discussed, and the ethics of bronchoscopic procedures, including bronchoscopic research in children. Advances in instrumentation, and also improved anaesthetic techniques, allow fibreoptic bronchoscopy to be safely performed in even very small, sick infants, provided proper precautions are taken.

The role of neutrophil apoptosis in the resolution of acute lung injury in newborn infants

BACKGROUND

The persistent airway neutrophilia observed in chronic lung disease of prematurity (CLD) may reflect inappropriate suppression of neutrophil apoptosis.

METHODS

134 bronchoalveolar lavage (BAL) samples were obtained from 32 infants requiring mechanical ventilation for respiratory distress syndrome (RDS): 13 infants (median gestation 26 weeks, range 23 to 28) subsequently developed CLD (CLD group), and 19 infants (gestation 31 weeks, range 25 to 39) recovered fully (RDS group). A further 73 BAL samples were obtained from 20 infants (median age 2 days, range 1 to 402) receiving extracorporeal membrane oxygenation (ECMO) for severe respiratory failure.

RESULTS

Neutrophil apoptosis was increased in the RDS group (mean (SEM) neutrophil apoptosis on day 7 BAL: RDS 17.0 (8.6)% v CLD 0.7 (0.2)% (p<0.05)). BAL fluid obtained from RDS but not CLD patients was proapoptotic to neutrophils (apoptosis ratio BAL fluid/saline control: day 1, RDS 9.8 (5.5) v CLD 1.2 (0.1) (p<0.05); day 2, RDS 4.32 (2.8) v CLD 0.5 (0.4) (p<0.05)). There were similar findings in the ECMO group: survivors had proapoptotic BAL fluid compared with non-survivors (apoptosis ratio day 1, survivors 7.9 (2.1) v non-survivors 2.1 (0.7) (p<0.05)).

CONCLUSIONS

Inappropriate suppression of neutrophil apoptosis may be associated with a poor outcome in newborn infants with respiratory failure.

Pilot investigation of hypothermia in neonates receiving extracorporeal membrane oxygenation

BACKGROUND

Infants requiring extracorporeal membrane oxygenation (ECMO) support represent a high risk group in terms of cerebral injury. Mild hypothermia both during and after cerebral hypoxic ischaemia appears to be a promising strategy for offering neuroprotection.

OBJECTIVE

To investigate whether mild hypothermia was both feasible and safe in infants receiving ECMO as a prelude to any formal assessment of this approach in a randomised trial.

METHODS

Twenty infants (body weight less than 5 kg) with severe cardiopulmonary insufficiency, referred for ECMO support at Glenfield Hospital, Leicester, were enrolled in this study. Twenty consecutive infants (compromising four groups of five) were studied. Baseline data were obtained from a control group who were run throughout their course at 37 degrees C. The patients in the next group were managed with a core temperature of 36 degrees C for the first 12 hours of their ECMO run, before being warmed up to 37 degrees C. After successful completion, the next group of five were cared for at 35 degrees C for the first 12 hours, and, there having been no previous complications, the final group were cared for at 34 degrees C for the first 12 hours. Patients were assessed clinically and biologically. In addition to routine laboratory tests, cytokines (interleukin 6, interleukin 8, tumour necrosis factor alpha, and C reactive protein) were measured and coagulation tests (D-dimer, thrombin-antithrombin III complex, plasmin-alpha(2)-antiplasmin complex) were performed serially for five days.

RESULTS

There were no significant differences among the four groups in gestational age, birth weight, age at the time of ECMO, Apgar scores at one and five minutes, pH before cannulation, oxygenation index, duration of ECMO, and survival rate to discharge from hospital. No adverse effects of mild hypothermia were found on patient management during ECMO. Laboratory data for up to five days of ECMO also showed no difference among the four groups.

CONCLUSION

Mild hypothermia (34 degrees C) for the initial 12 hours of an ECMO run is feasible.

Antenatal inflammation and infection in chronic lung disease of prematurity

In spite of improved neonatal care, chronic lung disease of prematurity (CLD) remains a major cause of morbidity and mortality in extremely preterm infants. Our current understanding is that antenatal infection can trigger intra-uterine inflammation which then promotes preterm labour. Recent studies suggest that antenatal infection and inflammation can also increase the preterm infant's susceptibility to develop CLD. It may be that exposure of the fetal lung to high concentrations of pro-inflammatory cytokines is the cause of this increased susceptibility. One candidate for initiating intra-uterine inflammation is ascending infection by the vaginal commensal Ureaplasma urealyticum (Uu). Antibiotics administered to mothers prior to delivery appear to improve the neonatal outcome in cases of preterm prolonged rupture of membranes, but not in cases of preterm labour with intact membranes. Uu can be transmitted vertically to the airways of the preterm infant, but the role of Uu in causing CLD remains uncertain. Small trials of antibiotics given to preterm infants after delivery have not shown any consistent benefit in reducing CLD. Although CLD remains a significant problem for the extremely preterm infant, it is likely that molecular biology techniques, such as the polymerase chain reaction, will enhance the detection of antenatal infection and further our understanding of the pathogenesis of CLD.

Management issues in CLD of prematurity

CLD is one of the major problems in neonatal medicine. Clinicians struggle to provide optimal care because of limited evidence. Many questions still need to be answered; meanwhile many aspects of management will remain best practice rather than evidence based.

Oxygen therapy for infants with chronic lung disease

Supplemental oxygen is a safe and effective treatment for infants with established chronic lung disease who are not at risk of further progression of retinopathy of prematurity (ROP). Oxygen saturations of < 92% should be avoided and a target range of at least 94-96% aimed for. The saturation target range for very preterm infants at risk of developing ROP is more controversial, but the therapeutic index is probably considerably narrower.

Fibroblast mitogenic activity of lung lavage fluid from infants with chronic lung disease of prematurity

BACKGROUND

Lung fibrosis is thought to be important in chronic lung disease of prematurity (CLD).

METHODS

Fibroblast proliferative activity was assessed in 207 bronchoalveolar lavage fluid (BALF) samples from 43 infants. Sixteen developed CLD (birth weight 765 g (630-1230), gestation 26.5 weeks (23-29)), 18 developed respiratory distress syndrome (RDS) (birth weight 1415 g (430-4160), gestation 31 weeks (23-39)), and nine control infants (birth weight 2110 g (900-3720), gestation 32 weeks (26-41)) received mechanical ventilation for non-pulmonary reasons.

RESULTS

The fibroblast proliferative activity relative to 10% fetal calf serum was 64-75% in infants with CLD, 55-86% in the RDS group, and 42-68% in control infants during the first 5 weeks of life. Only at day 3 was there a difference between the groups (CLD 72% v control 42%, p < 0.01; RDS 63% v control 42%, p < 0.05). With the use of neutralising antibodies, platelet derived growth factor BB (PDGF-BB) and epidermal growth factor were undetectable, and insulin-like growth factor I (IGF-I) accounted for 14% (p < 0.05) and 11% (p < 0.005) of BALF mitogenic activity from the RDS and CLD groups respectively.

CONCLUSIONS

The mitogenic activity of BALF was similar in the three groups studied and was only partially accounted for by IGF-I. Growth factors other than PDGF-BB and IGF-I contribute significantly to this process.