Rectal Acetaminophen Improves Shunt Volume and Reduces Patent Ductus Arteriosus Ligation in Extremely Preterm Infants

OBJECTIVE

An alternative therapy for preterm infants with a hemodynamically significant patent ductus arteriosus (hsPDA) is needed when cyclooxygenase inhibitors fail or where treatment is contraindicated due to coexisting renal failure, necrotizing enterocolitis, and/or intestinal perforation. No studies have evaluated the efficacy of per rectum (PR) acetaminophen. The study aimed to evaluate the efficacy of PR acetaminophen in modulating the risk of PDA ligation.

STUDY DESIGN

A retrospective matched case-control study was conducted to compare neonates born <29 weeks' gestation with evidence of hsDA, in an era when rescue rectal acetaminophen was used (January 2014-March 2018) as a treatment strategy, versus historical controls (July 2006-August 2012). All patients underwent comprehensive echocardiography assessment of ductal shunt volume according to a standardized protocol. Acetaminophen treated neonates were matched according to demographics, gestation, preintervention echocardiography features, and comorbidities. Control patients were selected when an echocardiography was performed at an equivalent postnatal age. Infants with a genetic syndrome, severe congenital malformation, or major forms of congenital heart disease excluding small atrial septal defect or ventricular septal defect, PDA, or patent formale ovale were excluded. The primary outcome was surgical ligation of the PDA. Secondary outcomes included echocardiography indices of hemodynamic significance, the composite of death, or severe BPD (defined by ventilator dependence at 36 weeks postmenstrual age). Descriptive statistics and univariate (t-tests, Fisher's exact test, and Mann-Whitney U test) analyses were used to evaluate clinical and echocardiography characteristics of the groups and compare outcomes.

RESULTS

Forty infants (20 cases and 20 controls), with similar demographic and echocardiography features, were compared. Cases received 6.8 ± 0.7 days (60 mg/kg/day) of PR acetaminophen. Responders (n = 12, 60%) had echocardiography evidence of reduced ductal diameter (2.2 mm [1.9-2.6] to 1.1 mm [0-1.7], p = 0.002), left ventricular output (363 ± 108-249 ± 61 mL/min/kg; p = 0.002) and left atrium to aortic root ratio (1.7 ± 0.3-1.3 ± 0.2; p = 0.002) following treatment. The rate of PDA ligation was 50% lower (p = 0.02) and composite outcome of death or severe bronchopulmonary dysplasia was reduced (p = 0.04) in the acetaminophen group.

CONCLUSION

Rectal acetaminophen was associated with improvement in echocardiography indices of PDA shunt volume, a 50% reduction in PDA ligation rates and a reduction in the composite outcome of death or severe BPD. Pharmacologic and further prospective clinical studies are needed.

KEY POINTS

· Many preterm infants encounter the clinical consequences of a hemodynamically significant PDA.. · The merits and optimal timing of PDA ligation remains an area of controversy amongst neonatologists.. · Cyclooxygenase inhibitors are associated with adverse events or are often contraindicated..

A104 PATIENT AND PUBLIC INVOLVEMENT (PPIN) IN IBD RESEARCH - A SCOPING REVIEW

Background

Over the past 10 years, interest in patient and public involvement (PPIn) in research has grown. Several arguments support the engagement of patients as partners in the research process. Patients with lived experience of a condition can offer their knowledge to study design as experience-based experts, helping researchers incorporate patient-pertinent outcomes. PPIn has also been shown to boost patient enrolment and retention in clinical trials. Benefits, challenges, and best practices of PPIn have been examined in other fields. However, to date, no study has examined PPIn in inflammatory bowel disease (IBD) research. Many factors amenable to research involvement may impact IBD patients’ quality of life, including disease morbidity, complications, and efficacy/side effects of therapy.

Aims

This review aims to characterize methods of PPIn in IBD research and highlight themes relating to best practices, benefits, and challenges.

Methods

We ran a systematic search on MEDLINE, EMBASE, and Cochrane for all IBD research studies in which IBD patients were involved in the research process. PPIn included but was not limited to patient input in one of the following 3 stages: Study Design (prioritization of research topics, outcome selection, study tool development), Study Execution (recruitment, data collection & analysis), and Dissemination of Research. After abstract and full-text screening, 14 studies were selected.

Results

Patients were recruited for PPIn through IBD and patient organizations (7/14), outpatient clinics (4/14), tertiary care sites (2/14), and pre-existing patient advisory groups (1/14). The majority of studies (11/14) engaged patients in the development of study materials, which included a physical activity intervention for stoma patients, an IBD pregnancy decision aid, and a quality of life questionnaire. Two studies interviewed patients to determine comprehensibility of survey items and guide revisions. One study involved patients in data analysis and manuscript development. Most consultations were open-ended, including focus groups (8/14) and semi-structured interviews (3/14). According to study authors, PPIn helps guide IBD research priorities by focusing on patient-relevant issues. Authors also cited the role of PPIn in designing patient-friendly study tools. One challenge reported by 2 studies was that PPIn requires patients to have access to high-quality information and requires a significant time commitment, which may contribute to demographic biases.

Conclusions

The majority of IBD studies engaged patients in an open-ended format and were engaged in study design, particularly in developing study materials. Authors recommend continuous involvement of patients throughout the research process to address their research priorities.

Funding Agencies

None

A242 STOOL FROM IBS-D PATIENT WITH A HISTORY OF A DYSBIOTIC AND NON-DYSBIOTIC ONSET MODULATE NEURONAL EXCITABILITY VIA DIFFERENT MECHANISMS

Background

We have shown that Irritable Bowel Syndrome diarrhea-predominant (IBS-D) patients with a history of a dysbiotic-like onset have distinct stool metabolomic profiles versus those with a non-dysbiotic-like onset. IBS stool supernatants can sensitize mouse colonic afferent nerves via both histamine and proteases. However, it is unknown if stool supernatants from the two IBS-D subgroups modulate the excitability of nociceptive neurons via different neuroactive mediators

Aims

To evaluate whether there are differences in neuroactive mediators within stool supernatants from subgroups of IBS-D patients that can modulate the excitability of nociceptive neurons.

Methods

Stool samples from healthy control (HC) (N=5) and IBS-D patients with a dysbiotic (N=7) or non-dysbiotic-like (N=7) onset, was homogenized with Krebs solution and filtered. Proteolytic activity was assessed using casein as a substrate with and without protease inhibitors. Histamine was quantified by ELISA. DRG neurons from C57BL/6 mice were incubated overnight or acutely (30 min) with stool supernatants. Some neurons were pre-incubated with PAR2 (GB83, 10 μM) or H1R (pyrilamine, 1μM) antagonists prior to supernatant incubation. Changes in neuronal excitability were assessed with perforated patch-clamp by measuring the rheobase (current that elicits an action potential).

Results

Proteolytic activity in dysbiotic-like (57.9 U/μg, p&lt;0.05) but not non-dysbiotic like (37.4 U/μg) stool supernatant was increased compared to HC (25.2 U/μg). Serine inhibitor decreased proteolytic activity of dysbiotic (46.6%, p&lt;0.05) and non-dysbiotic (34.2%, p&lt;0.01) supernatant whereas cysteine, aspartic and metalloproteases inhibitors had no effect. Histamine was increased 78% (p&lt;0.05) in IBS-D compared to HC. No differences in proteolytic activity and histamine concentration between IBS-D subtypes were found. In patch-clamp recordings, overnight incubation with dysbiotic (19%, p&lt;0.05) and non-dysbiotic (22%, p&lt; 0.01) stool supernatant decreased rheobase of DRG neurons compared to HC. No difference in rheobase was observed between IBS-D subtypes. GB83 blocked the overnight actions of supernatants from both subgroups, but pyrilamine had no effect. In contrast, following acute incubation, pyrilamine blocked the hyperexcitability evoked by dysbiotic like supernatant (60pA vs 48pA, p&lt;0.001) but had no effect on non-dysbiotic like supernatants.

Conclusions

Proteases in stool supernatants from IBS-D patients increase neuronal excitability but only those with a history of dysbiotic like onset acutely increase neuronal excitability through H1 receptors. These findings suggest that stool supernatants from subgroups of IBS-D may modulate nociceptor excitability via different mechanisms.

Funding Agencies

CIHRAmerican Neurogastroenterology and Motility Society

A243 HISTAMINE H1-RECEPTOR ANTAGONISTS SUPPRESS THE HYPEREXCITABILITY OF NOCICEPTIVE NEURONS EXPOSED TO IBS-C PATIENT STOOL SUPERNATANTS

Background

Abdominal pain is the primary cause of morbidity in many chronic GI disorders such as IBS, but the molecular mechanisms contributing to pain signaling are unclear. Stool supernatants from patients with diarrhea-predominant IBS increase the excitability of DRG neurons compared to supernatants from healthy controls, suggesting that mediators in the stool may sensitize nociceptors. Additionally, histamine has been implicated as a mediator of hypersensitivity in IBS patients. However, it is unclear if stool supernatants from constipation-predominant IBS (IBS-C) patients affect the excitability of DRG neurons. Furthermore, it is unknown if specific neuro-mediators in stool such as histamine impact the excitability of nociceptive neurons in this subgroup of IBS patients.

Aims

To evaluate whether IBS-C stool supernatants induce nociceptive signaling in DRG neurons compared to healthy control (HC) stool supernatants.

If so, to evaluate the role of histamine 1 (H1) receptors in DRG neuron nociceptive signaling initiated by mediators in IBS-C stool supernatants.

Methods

IBS-C (n=5) and HC (n=2) patient stool was collected, filtered, and dissolved with Krebs solution in a 1:8 (g/v) dilution. Dorsal root ganglion (DRG) neurons from C57BL/6 mice were incubated with HC or IBS-C stool supernatant for 30 minutes. To evaluate whether histamine in stool supernatants can sensitize H1 receptors on nociceptors, DRG neurons were pre-incubated with the H1-receptor antagonist pyrilamine (1μM, 30 min) before stool supernatants. Changes in DRG neuronal excitability were recorded using perforated patch-clamp techniques to measure the rheobase (minimum input current needed to elicit an action potential) and the resting membrane potential (RMP).

Results

In neurons incubated with IBS-C stool supernatants (n=28) the rheobase decreased (63%) compared to healthy controls (78 ± 13.7 pA; n=6). This effect was reversed in DRG neurons pre-incubated with the H1 receptor antagonist, pyrilamine, (n=26) (77 ± 5.9 pA, p&lt;0.001) compared to neurons incubated with IBS-C supernatant alone (50 ± 5.13 pA; n=28). No changes were found in the RMP. The data were analyzed with the non-parametric Kruskal-Wallis test.

Conclusions

IBS-C stool supernatants increase the excitability of DRG neurons compared to HC. Furthermore, the H1-receptor antagonist pyrilamine inhibits the neuronal hyperexcitability evoked by mediators in IBS-C patient stool. These findings suggest that the neuroactive metabolite histamine may contribute to visceral pain experienced by patients with IBS-C. Further studies are needed to examine whether similar signaling to nociceptive neurons by stool supernatants occurs in other subtypes of IBS.

Funding Agencies

CAG, CIHR

A79 AIMING TO PROVIDE EARLIER CARE WHILE REDUCING SPECIALTY CLINIC WAIT TIMES: DEVELOPING A RELIABLE PROCESS OF ASSESSING THE ELIGIBILITY OF GASTROENTEROLOGY REFERRALS FOR PRIMARY CARE PATHWAYS

Background

Gastrointestinal (GI) diseases are common and are a source of substantial morbidity, mortality, and cost, accounting for the largest share of medical referrals from primary care physicians (PCPs) in Canada. Long wait times and increasing numbers of referrals for GI consultation have thus become a significant issue, and while awaiting consultation many patients experience impaired quality of life. Primary care clinical pathways are structured care plans outlining detailed steps for treating patients with specific GI conditions, supporting the translation of clinical guidelines into local protocols and clinical practice.

Aims

To identify the proportion of referrals sent from PCPs to the Queen’s Gastroenterology division that meet the eligibility criteria for a clinical care pathway.

Methods

A review was conducted to identify the proportion of non-urgent referrals in triage sent from PCPs to the Queen’s Gastroenterology division that met the criteria for a clinical care pathway from July 2019 to May 2020. The reason for referral from PCP to gastroenterology was recorded. Individual patient characteristics included in each referral letter were assessed, including age, sex, GI symptoms or signs, relevant clinical features (i.e. time course of symptoms, frequency of bowel movements), relevant laboratory parameters (i.e. CBC, LFTs, electrolytes) or any investigations ordered to evaluate the cause of the patient’s symptoms or signs by the PCP. Four reviewers assessed an initial sample of 200 referral letters and classified each patient’s eligibility for a primary care pathway (GERD, diarrhea, IBS, dyspepsia, or ineligible). After every 100 referrals, discrepancies were reviewed, and a consensus was reached for each case. Data from 100 subsequent referral letters were collected by two independent reviewers, and the inter-rater reliability was calculated. Following a high level of agreement, the final 70 referrals were assessed by two reviewers.

Results

Out of 370 referrals sent from PCPs to the Queen’s Gastroenterology division from July 2019 to December 2019, a total of 170 (46%) met the eligibility criteria for a clinical care pathway. From the eligible referrals, the proportion of patients in each pathway were as follows: 35% GERD, 12% diarrhea, 34% IBS and 19% dyspepsia. The inter-rater reliability for the first 100 referrals assessed by two independent reviewers was 94% (κ = 0.873).

Conclusions

These findings demonstrate that a significant proportion of the patient population referred from PCPs to Queen’s Gastroenterology would be eligible for a primary care pathway. Future steps include implementing these pathways to determine their effectiveness in reducing wait times and empowering PCPs to care for patients who do not require specialist referral.

Funding Agencies

None

Haematological parameters and coagulation in umbilical cord blood following COVID-19 infection in pregnancy

Objective

The aim of this study was to evaluate infants, born to women with SARS-CoV-2 detected during pregnancy, for evidence of haematological abnormalities or hypercoagulability in umbilical cord blood.

Study design

This was a prospective observational case-control study of infants born to women who had SARS-CoV-2 RNA detected by PCR at any time during their pregnancy (n = 15). The study was carried out in a Tertiary University Maternity Hospital (8,500 deliveries/year) in Ireland. This study was approved by the Hospital Research Ethics Committee and written consent was obtained. Umbilical cord blood samples were collected at delivery, full blood count and Calibrated Automated Thrombography were performed. Demographics and clinical outcomes were recorded. Healthy term infants, previously recruited as controls to a larger study prior to the outbreak of COVID-19, were the historical control population (n = 10).

Results

Infants born to women with SARS-CoV-2 had similar growth parameters (birth weight 3600 g v 3680 g, p = 0.83) and clinical outcomes to healthy controls, such as need for resuscitation at birth (2 (13.3%) v 1 (10%), p = 1.0) and NICU admission (1 (6.7%) v 2 (20%), p = 0.54). Haematological parameters (Haemoglobin, platelet, white cell and lymphocyte counts) in the COVID-19 group were all within normal neonatal reference ranges. Calibrated Automated Thrombography revealed no differences in any thrombin generation parameters (lag time (p = 0.92), endogenous thrombin potential (p = 0.24), peak thrombin (p = 0.44), time to peak thrombin (p = 0.94)) between the two groups.

Conclusion

In this prospective study including eligible cases in a very large population of approximately 1500 women, there was no evidence of derangement of the haematological parameters or hypercoagulability in umbilical cord blood due to COVID-19. Further research is required to investigate the pathological placental changes, particularly COVID-19 placentitis and the impact of different strains of SARS-CoV-2 (particularly the B.1.1.7 and the emerging Delta variant) and the severity and timing of infection on the developing fetus.

Clinical and echocardiography predictors of response to inhaled nitric oxide in hypoxemic term and near-term neonates

Approximately 40% of hypoxemic term/near-term neonates are nonresponders to inhaled nitric oxide (iNO). Phenotypic characterization of patients less likely to respond may improve diagnostic precision and therapeutic decisions. We conducted a retrospective cohort study of neonates born ≥35 weeks gestation with hypoxemia who received iNO in the first 72 h of life and classified them into responders and nonresponders according to changes in the fraction of inspired oxygen, saturations and/or arterial partial pressure of oxygen after 1 h of administration. Comprehensive targeted neonatal echocardiography (TnECHO) data were collected when performed up to 6 h prior or 24 h after iNO initiation. Descriptive statistics, univariate analysis, and binary logistic regression were used to compare the groups. There were 183 patients included (63% responders) and TnECHO was performed in 54 infants. The presence of lung disease, and particularly meconium aspiration syndrome (p = .004), was associated with nonresponse to iNO. Nonresponders were characterized by a higher need for rescue high-frequency ventilation (p < .001), longer duration of mechanical ventilation (p < .001), and need for oxygen support (p = .003). Pulmonary hypertension documented on TnECHO was present in 96.3% of the patients but there was no difference in frequency or severity of pulmonary hypertension, or rates of low cardiac output between the groups. Moderate-to-severe right ventricular systolic dysfunction (p > .05) and lower left ventricular strain (p < .05) were more likely in the nonresponder group. In summary, response to iNO is influenced by lung disease, choice of ventilation strategy, and perhaps underlying cardiovascular physiology. Prospective pre- and post-iNO echocardiography data may provide novel physiologic insights.

Multicentre prospective observational study exploring the predictive value of functional echocardiographic indices for early identification of preterm neonates at risk of developing chronic pulmonary hypertension secondary to chronic neonatal lung disease

INTRODUCTION

Although chronic pulmonary hypertension (cPH) secondary to chronic neonatal lung disease is associated with increased mortality and respiratory and neurodevelopmental morbidities, late diagnosis (typically ≥36 weeks postmenstrual age, PMA) and the use of qualitative echocardiographic diagnostic criterion (flat interventricular septum in systole) remain significant limitations in clinical care. Our objective in this study is to evaluate the utility of relevant quantitative echocardiographic indices to identify cPH in preterm neonates, early in postnatal course and to develop a diagnostic test based on the best combination of markers.

METHODS AND ANALYSIS

In this ongoing international prospective multicentre observational diagnostic accuracy study, we aim to recruit 350 neonates born <27 weeks PMA and/or birth weight <1000 g and perform echocardiograms in the third week of age and at 32 weeks PMA (early diagnostic assessments, EDA) in addition to the standard diagnostic assessment (SDA) for cPH at 36 weeks PMA. Predefined echocardiographic markers under investigation will be measured at each EDA and examined to create a scoring system to identify neonates who subsequently meet the primary outcome of cPH/death at SDA. Diagnostic test characteristics will be defined for each EDA. Pulmonary artery acceleration time and tricuspid annular plane systolic excursion are the primary markers of interest.

ETHICS AND DISSEMINATION

Ethics approval has been received by the Mount Sinai Hospital Research Ethics Board (REB) (#16-0111-E), Sunnybrook Health Sciences Centre REB (#228-2016), NHS Health Research Authority (IRAS 266498), University of Iowa Human Subjects Office/Institutional Review Board (201903736), Rotunda Hospital Research and Ethics Committee (REC-2019-008), and UBC Children's and Women's REB (H19-02738), and is under review at Boston Children's Hospital Institutional Review Board. Study results will be disseminated to participating families in lay format, presented to the scientific community at paediatric and critical care conferences and published in relevant peer-reviewed journals.

TRAIL REGISTRATION NUMBER

NCT04402645.

A234 EVALUATING THE EFFECT OF STOOL SUPERNATANTS FROM IBS PATIENTS AND HEALTHY CONTROLS ON THE EXCITABILITY OF DRG NEURONS

Background

Abdominal pain is commonly described in chronic disorders such as irritable bowel syndrome (IBS), but the underlying mechanisms are currently unclear. The stool metabolomic and microbiota profiles of IBS and healthy patients have shown distinct differences. Additionally, IBS stool supernatants have previously been demonstrated to induce hypersensitivity of nociceptive nerves in the ex vivo mouse colon, suggesting that mediators in the stool can sensitize nociceptors. However, the effects of healthy control (HC) or IBS patient stool supernatants on the excitability of DRG neurons have not been clarified.

Aims

To evaluate the effect of HC and IBS supernatant on DRG neurons.

Methods

HC (n=8 patients) or IBS (n=10 patients) stool was collected, dissolved and homogenized with bicarbonate-buffered Krebs solution at 37°C in a 1/10 dilution. DRG neurons from C57BL/6 mice were dissociated and incubated overnight with HC or IBS supernatant in a Krebs dissolution. Changes in DRG neuronal excitability were recorded using perforated patch-clamp techniques to measure the rheobase (amount of current needed to elicit an action potential). The effect of the IBS and HC stool supernatants on the resting membrane potential (RMP) was also recorded.

Results

Overnight incubations with supernatant of HC stool diluted in Krebs solution (n=28 neurons) did not significantly decrease the rheobase compared to control neurons (n=22) (62.7 ± 3.9 pA vs 64.2 ± 2.7 pA). In a parallel experiment, we evaluated the effect of IBS stool supernatants diluted in Krebs (n=52 neurons) and found that they significantly decreased the rheobase compared to the supernatant of HC diluted in Krebs and control neurons (52.3 ± 2.3; p&lt;0.05). The data were analyzed with a one-way ANOVA and Tukey’s test. Incubations with IBS supernatant decreased the RMP compared to HC supernatant (-42.6 ± 0.6 mV vs. -46.0 ± 0.9 mV; p&lt;0.01), which was calculated with an unpaired t-test.

Conclusions

These findings suggest that mediators in IBS stool increase the excitability of DRG neurons compared to HC stool supernatant, and thus may contribute to pain signaling in IBS patients.

Funding Agencies

CIHR

Dual endothelin-1 receptor antagonism attenuates platelet-mediated derangements of blood coagulation in Eisenmenger syndrome

Essentials Eisenmenger syndrome is characterised by thrombotic and hemorrhagic risks of unclear aetiology. Calibrated automated thrombography was used to assess these coagulation derangements. Platelet activity supported abnormalities in procoagulant and anticoagulant pathway function. Endothelin-1 antagonism appeared to ameliorate these derangements.

SUMMARY

Aims The mechanisms underlying the competing thrombotic and hemorrhagic risks in Eisenmenger syndrome are poorly understood. We aimed to characterize derangements of blood coagulation and to assess the effect of dual endothelin-1 receptor antagonism in modulating hemostasis in this rare disorder. Methods In a 10-month recruitment period at a tertiary cardiology referral center, during which time there were over 14 000 outpatient consultations, consecutive subjects with Eisenmenger syndrome being considered for macitentan therapy (n = 9) and healthy volunteers (n = 9) were recruited. Plasma thrombin generation in platelet-rich and platelet-poor plasma was assessed by calibrated automated thrombography prior to and following therapy. Results Median peak plasma thrombin generation was higher in platelet-rich plasma obtained from Eisenmenger syndrome subjects relative to controls (median peak thrombin [25th-75th percentile]: 228.3 [206.5-258.6] nm vs. 169.9 [164.3-215.8] nm), suggesting a critical mechanistic role for platelets in supporting abnormal hypercoagulability in Eisenmenger syndrome. Abnormal enhanced sensitivity to the anticoagulant activity of activated protein C was also observed in platelet-rich plasma in Eisenmenger syndrome, suggesting that derangements of platelet activity may influence the activity of anticoagulant pathways in a manner that might promote bleeding in this disease state. Following 6 months of macitentan therapy, attenuations in the derangements in both procoagulant and anticoagulant pathways were observed. Conclusions Abnormal platelet activity contributes to derangements in procoagulant and anticoagulant pathways in Eisenmenger syndrome. Therapies targeting the underlying vascular pathology appear to ameliorate these derangements and may represent a novel strategy for the management of the competing prothrombotic and hemorrhagic tendencies in this disorder.

Timing of administration of antenatal magnesium sulfate and umbilical cord blood magnesium levels in preterm babies

BACKGROUND

The optimum timing of administration of magnesium sulfate (MgSO₄) in relation to delivery is not known. The general consensus is to achieve administration to the mother at least 4 hours prior to preterm delivery.

OBJECTIVE

To investigate potential predictors of umbilical cord blood magnesium (Mg) concentrations, in particular, timing of antenatal MgSO₄ administration in relation to delivery.

STUDY DESIGN

A prospective observational study of infants delivered at less than 32 weeks' gestational age. Cord bloods samples were collected at delivery and Mg levels analyzed.

RESULTS

Of the 81 included cases, five received no antenatal MgSO₄, 65 received a 4 g bolus only, and 11 received a 4 g bolus and 1 g/hour infusion. The median time of bolus administration before delivery was 104 minutes (IQR: 57-215). The mean magnesium level was 0.934 mmol/L in the no antenatal MgSO₄ group, 1.018 mmol/L in the bolus only group, and 1.225 mmol/L in the bolus and infusion group (p < .05). In the bolus only group, the highest mean magnesium concentration (1.091 mmol/L) was achieved with administration 1-2 hours before delivery, but the difference was small and not statistically significant. On multiple regression analysis, lower birthweight Z scores and gestational age were independently associated with higher cord blood Mg levels.

CONCLUSIONS

In the bolus only group, the highest mean Mg levels were observed with administration 1-2 hours before delivery, but the findings were not statistically significant. Compared to the rest of the cohort, higher Mg levels were found when a bolus was followed by an infusion. Following a MgSO₄ bolus, some growth restricted extremely preterm babies may have higher Mg levels than would be otherwise expected.

Endothelial barrier protective properties of low molecular weight heparin: A novel potential tool in the prevention of cancer metastasis?

BACKGROUND

One of the key events in the progression of cancer metastasis is the trans-endothelial migration of circulating tumor cells. Moreover, inhibition of tumor-induced vascular permeability has been shown to inhibit metastasis in vivo. Low molecular weight heparin (LMWH) appears to confer a survival benefit in cancer but the underlying mechanisms are poorly understood.

OBJECTIVE

To characterise LMWH-mediated endothelial barrier protection and to explore strategies to limit the LMWH-associated haemorrhagic risk in this setting.

METHODS

Endothelial barrier function was assessed using in vitro assays of endothelial permeability and tumor cell trans-endothelial migration. Thrombin-mediated activation of PAR-1 signalling was assessed by flow cytometry and western blotting. LMWH anticoagulant activity was assessed by calibrated automated thrombography and plasma anti-factor Xa activity assay.

RESULTS

LMWH tinzaparin enhanced endothelial barrier function and reduced tumor cell trans-endothelial migration (73.9±5.7% of baseline; P<.05). Tinzaparin-mediated attenuation of thrombin-induced permeability was not mediated through an inhibition of thrombin proteolytic activity. In addition, fractions of LMWH with diminished anticoagulant activity retained endothelial barrier protective properties and a marked synergistic effect on barrier function was observed using combinations of sub-anticoagulant concentrations of tinzaparin with simvastatin (which exhibits endothelial barrier protective properties in vitro), with almost complete protection against agonist-induced endothelial barrier permeability achieved (7.9±0.2% of baseline; P<.05).

CONCLUSION

Collectively, these results suggest that LMWH supports endothelial barrier function in a manner which does not appear to be dependent on its anticoagulant activity. If replicated in vivo, these findings could represent a novel therapeutic approach to the suppression of metastasis.

Coagulation indices in very preterm infants from cord blood and postnatal samples

BACKGROUND

Very premature infants are at high risk of bleeding complications; however, few data exist on ranges for standard coagulation tests.

OBJECTIVES

The primary objective of this study was to measure standard plasma coagulation tests and thrombin generation in very premature infants compared with term infants. The secondary objective was to evaluate whether an association existed between coagulation indices and intraventricular hemorrhage (IVH).

PATIENTS/METHODS

Cord and peripheral blood of neonates < 30 weeks gestational age (GA) was drawn at birth, on days 1 and 3 and fortnightly until 30 weeks corrected gestational age. Prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen and coagulation factor levels were measured and tissue factor-stimulated thrombin generation was characterized. Control plasma was obtained from cord blood of term neonates.

RESULTS

One hundred and sixteen infants were recruited. Median (range) GA was 27.7 (23.7-29.9) weeks and mean (SD) birth weight was 1020 (255) g. Median (5th-95th percentile) day 1 PT, APTT and fibrinogen were 17.5 (12.7-26.6) s, 78.7 (48.7-134.3) s and 1.4 (0.72-3.8) g L(-1) , respectively. No difference in endogenous thrombin potential between preterm and term plasma was observed, where samples were available. Levels of coagulation factors II, VII, IX and X, protein C, protein S and antithrombin were reduced in preterm compared with term plasma. Day 1 APTT and PT were not associated with IVH.

CONCLUSION

In the largest cross-sectional study to date of very preterm infants, typical ranges for standard coagulation tests were determined. Despite long clotting times, thrombin generation was observed to be similar in very preterm and term infants.

Specific allergen immunotherapy use in 2012: an Irish Paediatric Surveillance Unit (IPSU) study

Specific immunotherapy (SIT) is a disease modifying treatment for allergic rhinitis (AR), with its benefits most evident in those who are refractory to medical treatment. It is used less frequently in UK than Europe/US. No data exist on SIT use in Ireland. We audited paediatric practice to evaluate patient selection, SIT modalities and adverse events (A.E.). A 9 item questionnaire was sent to Irish paediatricians, identified via the Irish Paediatric Surveillance Unit (IPSU) mailing list. 58 children have undertaken SIT (Subcutaneous SCIT =3, Sublingual = 55). This represents 0.01% of Irish children estimated to have AR. 33 (56%) had asthma; 18 (55%) had perennial asthma, 7 (21%) seasonal asthma. Adverse events occurred in 5 cases (8.6%). Three treatments (3-5%) were discontinued as a result. SIT is available across Ireland, though only extremely small numbers of children with AR are being treated yet. Co-morbid asthma is frequent and does not increase adverse events. This audit will raise awareness of SIT use for AR in Ireland.

Sleep disorders in children with developmental delay

Developmental disorders in children are common. Associated demanding co-morbidities that include sleep problems are prevalent in this group. In turn, these are linked to daytime performance issues, reduced developmental and academic growth, and considerable familial psychopathology. Behavioral modification measures are and should be the first line approach to management. Medications for sleep disorders have an important role in addition to behavioral modification therapy. This literature review looks into the occurrence and severity of sleep problems in children with developmental disorders. The probable advantages of using medications, mainly focusing on the neurohormone melatonin (a sleep inducer), are also explored.

Laboratory coagulation parameters in extremely premature infants born earlier than 27 gestational weeks upon admission to a neonatal intensive care unit

BACKGROUND

Few published data exist to guide interpretation of coagulation times in extremely premature infants.

OBJECTIVE

To determine coagulation reference ranges on day 1 of life in extremely premature infants.

METHODS

A retrospective review of day 1 coagulation tests was performed in 144 infants <27 weeks' gestation between 2004 and 2010 in a tertiary neonatal unit. Samples were drawn through a non-heparinized umbilical or peripheral venous catheter as part of routine clinical care.

RESULTS

Mean (SD) and median (range) prothrombin times (PT) of 21.5 (5.3) and 20.2 (13.3-39) s, respectively, activated partial thromboplastin times (APTT) of 75.2 (27.8) and 67.4 (34.9-191.6) s, respectively, and plasma fibrinogen levels of 1.9 (1.1) and 1.4 (0.5-4.8) g/l, respectively, were reported. Using reference intervals derived from the 2.5th to 97.5th centiles, ranges of 14.4-36.7 s, 40.5-158.5 s and 0.7-4.8 g/l were determined for PT, APTT and plasma fibrinogen levels, respectively. In a subcohort with grade 0-2 intraventricular haemorrhage (n = 92), mean PT and APTT were 20.9 and 71.3 s, respectively, versus mean PT and APTT of 23.1 and 88.4 s (p = 0.06 and p = 0.03), respectively for those with grade 3-4 intraventricular haemorrhage. Mean PT and APTT in a cohort of infants defined to be small for gestational age were 22 and 76.8 s. These results did not differ significantly from non-small for gestational age infants, with a mean PT and APTT of 19.5 and 73.4 s (p = 0.09 and p = 0.7).

CONCLUSIONS

Reference ranges based on retrospective data were determined for PT, APTT and fibrinogen in a large cohort of extremely preterm infants.

Thought-action fusion in individuals with OCD symptoms

Rachman (Rachman, S. (1993). Obsessions, responsibility, and guilt. Behaviour Research and Therapy, 31, 149-154) suggested that patients with OCD may interpret thoughts as having special importance, thus experiencing thought-action fusion (TAF). Shafran, Thordarson and Rachman (Shafran, R., Thordarson, D. S. & Rachman, S. (1996). Thought-action fusion in obsessive compulsive disorder. Journal of Anxiety Disorders, 710, 379-391) developed a questionnaire (TAF) and found that obsessives scored higher than non-obsessives on the measure. In the current study, we modified the TAF to include a scale that assessed the "likelihood of events happening to others" as well as ratings of the responsibility and cost for having these thoughts. Replicating previous findings, we found that individuals with OC symptoms gave higher ratings to the likelihood of negative events happening as a result of their negative thoughts. Individuals with OC symptoms also rated the likelihood that they would prevent harm by their positive thoughts higher than did individuals without OC symptoms. These results suggest that the role of thought-action fusion in OCs may extend to exaggerated beliefs about thoughts regarding the reduction of harm.