Effect of inspiratory rise time on sputum movement during ventilator hyperinflation in a test lung model.

OBJECTIVES: Physiotherapists may use ventilator hyperinflation to enhance secretion clearance for intubated patients. This study investigated the effects of altering percentage inspiratory rise time (IRT) on sputum movement, ratio of peak inspiratory to expiratory flow rate (PIF:PEF ratio) and net peak expiratory flow (PEF) during ventilator hyperinflation in a test lung model. DESIGN: Laboratory-based bench study. INTERVENTIONS: Simulated sputum (two viscosities) was inserted into clean, clear tubing and connected between a ventilator and a resuscitation bag. Thirty-six ventilator hyperinflation breaths were applied for each 5% incremental increase in IRT between 0% and 20%. MAIN OUTCOME MEASURES: The primary outcome was sputum displacement (cm). Secondary outcomes included PIF:PEF ratio and net PEF. RESULTS: Significant cephalad sputum movement of 2.42cm (1.59 to 3.94) occurred with IRT between 5% and 20%, compared with caudad movement of 0.53 cm (0.31 to 1.53) at 0% IRT (median sputum movement difference 3.7cm, 95% confidence interval 2.2 to 4.8, P<0.001). Incremental increases in IRT percentage produced linear enhancements in PIF:PEF ratio and net PEF for both sputum concentrations (P<0.001). However, once the critical threshold for PIF:PEF ratio of 0.9 was achieved, the distance of sputum movement remained consistent for all IRT values exceeding 5%. CONCLUSIONS: Significant increases in sputum movement occurred when IRT percentage was lengthened to achieve the optimal PIF:PEF ratio, irrespective of sputum viscosity. This provides a theoretical rationale for therapists to consider this technique when treating mechanically ventilated patients. As no additional sputum movement was seen beyond the critical PIF:PEF ratio threshold, a low IRT percentage may potentially be used to achieve effective sputum movement.

Isolation and structural elucidation by 2D NMR of planteose, a major oligosaccharide in the mucilage of chia (Salvia hispanica L.) seeds.

An oligosaccharide was isolated in high purity and excellent yield from the water-extractable mucilage of chia (Salvia hispanica L.) seeds using an optimized solid-phase extraction method. LC-MS analysis showed that the compound presents a molecular mass of 504Da and trifluoroacetic acid hydrolysis revealed that it consists of galactose, glucose and fructose. Glycosidic linkage analysis showed that the oligosaccharide contains two non-reducing ends corresponding to terminal glucopyranose and terminal galactopyranose, respectively. The oligosaccharide was identified as planteose by the complete assignment of a series of 2D NMR spectra (COSY, TOCSY, ROESY, HSQC, and HMBC). The significance of the presence of planteose in chia seeds is discussed in the context of nutrition and food applications.

Opportunities for maternal transport for delivery of very low birth weight infants.

OBJECTIVE: To assess frequency of very low birth weight (VLBW) births at non-level III hospitals. STUDY DESIGN: Retrospective cohort study using linked California birth certificate and discharge data of 2008 to 2010 for deliveries of singleton or first-born infant of multiple gestations with birth weight 400 to 1500 g. Delivery rates by neonatal level of care were obtained. Risk of delivery at non-level III centers was estimated in univariable and multivariable models. RESULTS: Of the 1 508 143 births, 13 919 (9.2%) were VLBW; birth rate at non-level III centers was 14.9% (8.4% in level I and 6.5% in level II). Median rate of VLBW births was 0.3% (range 0 to 4.7%) annually at level I and 0.5% (range 0 to 1.6%) at level II hospitals. Antepartum stay for >24 h occurred in 14.0% and 26.9% of VLBW births in level I and level II hospitals, respectively. CONCLUSION: Further improvement is possible in reducing VLBW infant delivery at suboptimal sites, given the window of opportunity for many patients.

The incidence, risk and functional outcomes of intracranial haemorrhage in children with inherited bleeding disorders at one haemophilia center.

INTRODUCTION: Intracranial haemorrhage (ICH) is the most serious bleeding event for patients with inherited bleeding disorders (IBD). The risks and long-term consequences remain unknown. AIM: This single-centre service evaluation aimed to identify the incidence, risks and long-term outcomes following ICH in patients with IBD. METHODS: The IBD database and medical notes between 1987 and 2013 were reviewed. Children without apparent neurological deficit following ICH completed standardized assessments and supplementary information sheets. RESULTS: ICH was confirmed in 38/1111 children with IBD. The overall risk of ICH amongst children with IBD was 3.4% (95% CI: 2.5, 4.7%). However, 27/38 had an ICH in the first year of life, 18 of which were in the neonatal period. In children with IBD who had an ICH, the risks of ICH in the neonatal period or first year of life were 18/38 (47%) (95% CI: 32, 63%) and 27/38 (71%) (95% CI: 55, 83%) respectively. Mortality risk from ICH in children with an IBD was 5/38 (13%) (95% CI: 5.8, 27.3 %). Ten of 32 survivors had known neurological sequelae including motor disorder deficits (MDD) while 22 had no documented evidence of neurological impairment or MDD. Re-evaluation was possible in 17/22 children, 8 of whom demonstrated evidence of MDD. After re-evaluation, the risk of significant neurological MDD from ICH increased from 31% CI (95% CI: 18, 49%) to 56% CI (95% CI: 39, 72%). CONCLUSION: Risks and consequences of ICH in IBD were highest within the neonatal period and first year of life. MDD after ICH was not reliably identified in early life and ongoing monitoring in the first decade of life will facilitate educational support or physical rehabilitation.

Ising Model Reprogramming of a Repeat Protein's Equilibrium Unfolding Pathway.

Repeat proteins are formed from units of 20-40 aa that stack together into quasi one-dimensional non-globular structures. This modular repetitive construction means that, unlike globular proteins, a repeat protein's equilibrium folding and thus thermodynamic stability can be analysed using linear Ising models. Typically, homozipper Ising models have been used. These treat the repeat protein as a series of identical interacting subunits (the repeated motifs) that couple together to form the folded protein. However, they cannot describe subunits of differing stabilities. Here we show that a more sophisticated heteropolymer Ising model can be constructed and fitted to two new helix deletion series of consensus tetratricopeptide repeat proteins (CTPRs). This analysis, showing an asymmetric spread of stability between helices within CTPR ensembles, coupled with the Ising model's predictive qualities was then used to guide reprogramming of the unfolding pathway of a variant CTPR protein. The designed behaviour was engineered by introducing destabilising mutations that increased the thermodynamic asymmetry within a CTPR ensemble. The asymmetry caused the terminal α-helix to thermodynamically uncouple from the rest of the protein and preferentially unfold. This produced a specific, highly populated stable intermediate with a putative dimerisation interface. As such it is the first step in designing repeat proteins with function regulated by a conformational switch.

Term elective induction of labour and perinatal outcomes in obese women: retrospective cohort study.

OBJECTIVE: To compare perinatal outcomes between elective induction of labour (eIOL) and expectant management in obese women. DESIGN: Retrospective cohort study. SETTING: Deliveries in California in 2007. POPULATION: Term, singleton, vertex, nonanomalous deliveries among obese women (n = 74 725). METHODS: Women who underwent eIOL at 37 weeks were compared with women who were expectantly managed at that gestational age. Similar comparisons were made at 38, 39, and 40 weeks. Results were stratified by parity. Chi-square tests and multivariable logistic regression were used for statistical comparison. MAIN OUTCOME MEASURES: Method of delivery, severe perineal lacerations, postpartum haemorrhage, chorioamnionitis, macrosomia, shoulder dystocia, brachial plexus injury, respiratory distress syndrome. RESULTS: The odds of caesarean delivery were lower among nulliparous women with eIOL at 37 weeks [odds ratio (OR) 0.55, 95% confidence interval (CI) 0.34-0.90] and 39 weeks (OR 0.77, 95% CI 0.63-0.95) compared to expectant management. Among multiparous women with a prior vaginal delivery, eIOL at 37 (OR 0.39, 95% CI 0.24-0.64), 38 (OR 0.65, 95% CI 0.51-0.82), and 39 weeks (OR 0.67, 95% CI 0.56-0.81) was associated with lower odds of caesarean. Additionally, eIOL at 38, 39, and 40 weeks was associated with lower odds of macrosomia. There were no differences in the odds of operative vaginal delivery, lacerations, brachial plexus injury or respiratory distress syndrome. CONCLUSIONS: In obese women, term eIOL may decrease the risk of caesarean delivery, particularly in multiparas, without increasing the risks of other adverse outcomes when compared with expectant management.

The impact of change in pregnancy body mass index on the development of gestational hypertensive disorders.

OBJECTIVE: To examine the impact of change in body mass index (BMI) during pregnancy on the incidence of gestational hypertension/preeclampsia. STUDY DESIGN: This is a retrospective cohort study using linked California birth certificate and discharge diagnosis data from the year 2007. Adjusted odds ratios (aOR) and 95% confidence intervals (CI) were calculated for the outcome of gestational hypertension/preeclampsia, as a function of a categorical change in pregnancy BMI: BMI loss (<-0.5), no change (-0.5 to 0.5), minimal (0.6 to 5), moderate (5.1 to 10) and excessive (>10). The impact of change in pregnancy BMI was evaluated for the entire cohort and then as a function of prepregnancy BMI category. Women with no change in pregnancy BMI served as the reference group. RESULT: The study population consisted of 436 414 women with singleton gestations. Overall, women with excessive BMI change had a nearly twofold increased odds of gestational hypertension/preeclampsia (aOR=1.94; 95% CI=1.72 to 2.20). By prepregnancy BMI class, overweight and obese women who had a moderate change in pregnancy BMI also had increased odds of developing gestational hypertension/preeclampsia with aOR ranging from 1.73 to 1.97. CONCLUSION: Regardless of prepregnancy BMI category, women with excessive BMI change have a higher chance of developing gestational hypertension/preeclampsia. Overweight and obese women with moderate BMI change may also be at increased risk.

Factors affecting the Haemophilia Joint Health Score in children with severe haemophilia.

Joint damage from bleeding episodes leads to physical or functional limitations in people with haemophilia. Various factors may influence the frequency and severity of joint damage. This study examined whether age, prophylaxis, history of high-titre inhibitors (HTI) and bleeding events influenced the Haemophilia Joint Health Score (HJHS) in children. Medical and physiotherapy notes of boys with severe haemophilia, aged 4-18 years, were reviewed to identify factors associated with increased HJHS. The HJHS of 83 boys (median age: 11) ranged from 0 to 25, with 44/83 (53%) having a score of zero. The median HJHS was 0 (mean 2.6). In the non-HTI group, the HJHS for boys on late prophylaxis was 2.68 times higher than those who started early and the HJHS was on average 10% higher for every additional recent bleed. In this group the odds of having a zero score fell by 30% for every year increase in age. Boys with a history of HTI had higher HJHS scores than the non-HTI group, and age, number of recent bleeds and tolerized status were positively associated with HJHS. The score rose on average by 28% for every year of age and by 76% for non-tolerized boys. This study provides further evidence supporting early prophylaxis use and the importance of immune tolerance therapy. The HJHS is a useful tool for identifying and tracking changes in joint health with respect to therapy or disease progression. With improvements in haemophilia treatment, the disproportionate number of zero scores will continue to make interpretation of the HJHS challenging.

Nursing student voices: reflections on an international service learning experience.

For the past decade participation in service and experiential learning in higher education has increased. The purpose of this study was to explore the lived experience of BSN and MSN students participating in a multidisciplinary service-learning course in a rural, underserved village in Belize. Researchers analyzed student journals utilizing qualitative data analysis techniques. There were eight consistent themes found in the student journals. The findings indicate that international service learning opportunities increase students' awareness of their place in a global society and the potential contribution they can make in society. For the past decade, service and experiential learning in higher education, including nursing education, has become increasingly important. Simply put, service and experiential learning combine community service activities with a student's academic study for the sole purpose of enriching the academic experience. As faculty, we feel the goal of baccalaureate and graduate nursing education is to produce an educated professional who will become a responsible citizen.

Modulation of the multistate folding of designed TPR proteins through intrinsic and extrinsic factors.

Tetratricopeptide repeats (TPRs) are a class of all alpha-helical repeat proteins that are comprised of 34-aa helix-turn-helix motifs. These stack together to form nonglobular structures that are stabilized by short-range interactions from residues close in primary sequence. Unlike globular proteins, they have few, if any, long-range nonlocal stabilizing interactions. Several studies on designed TPR proteins have shown that this modular structure is reflected in their folding, that is, modular multistate folding is observed as opposed to two-state folding. Here we show that TPR multistate folding can be suppressed to approximate two-state folding through modulation of intrinsic stability or extrinsic environmental variables. This modulation was investigated by comparing the thermodynamic unfolding under differing buffer regimes of two distinct series of consensus-designed TPR proteins, which possess different intrinsic stabilities. A total of nine proteins of differing sizes and differing consensus TPR motifs were each thermally and chemically denatured and their unfolding monitored using differential scanning calorimetry (DSC) and CD/fluorescence, respectively. Analyses of both the DSC and chemical denaturation data show that reducing the total stability of each protein and repeat units leads to observable two-state unfolding. These data highlight the intimate link between global and intrinsic repeat stability that governs whether folding proceeds by an observably two-state mechanism, or whether partial unfolding yields stable intermediate structures which retain sufficient stability to be populated at equilibrium.

Effect of chest wall vibration timing on peak expiratory flow and inspiratory pressure in a mechanically ventilated lung model.

OBJECTIVE: To investigate the effects of chest wall vibration timing on air flow and pressure in a ventilated lung model. DESIGN: Laboratory-based bench study. PARTICIPANTS: Thirty physiotherapists with experience in intensive care. INTERVENTION: Physiotherapists applied three sets of eight chest wall vibrations to an intubated, mechanically ventilated mannequin. Vibrations were applied at the start of expiration (optimal), mid to late inspiration (early) and early to mid expiration (late). Air flow, peak pressure and volume were measured continuously. Forces applied during vibrations were recorded using a force-sensing mat, placed under the physiotherapists' hands. RESULTS: During optimal and early vibrations, peak expiratory flow increased significantly compared with baseline ventilation [mean difference for optimal vibrations 8.8l/minute, 95% confidence interval (CI) 6.0 to 11.6; mean difference for early vibrations 7.0l/minute, 95% CI 4.3 to 9.9]. Late vibrations did not enhance expiratory flow. Peak inspiratory pressure was significantly higher during early vibrations compared with baseline values (mean difference 5.6cmH(2)O, 95% CI 2.9 to 8.2). Peak inspiratory pressure generated during early vibrations was, on average, 8.4cmH(2)O greater than with optimal timing. CONCLUSION: The safety and effectiveness of respiratory physiotherapy treatments are likely to be influenced by the timing of vibrations within the breath cycle. Early vibrations generate potentially dangerous peak inspiratory pressures. Late vibrations, although not harmful, are not effective at increasing peak expiratory flow. This is an important consideration when training physiotherapists and evaluating outcomes of treatments in intensive care.

Long-term consequences of intracranial haemorrhage in children with haemophilia.

Intracranial haemorrhages (ICH) in children with haemophilia are rare, and the outcome is variable, ranging from no apparent impairment to death. The aim of this investigation was to identify if children with haemophilia and ICH, have any long-term problems with motor function, visual motor integration or strengths and difficulties compared with a control group. A review of the Haemophilia Database at Great Ormond Street Hospital for Children NHS Trust was undertaken to identify boys with haemophilia and a history of ICH, as well as a control group of peers with no such history. Boys were born between January 1994 and December 2002. All boys were assessed using the movement Assessment Battery for Children, the Developmental Test of Visual Motor Integration and The Strengths and Difficulties Questionnaire as standardized assessments of motor competence, visual motor integration and behavioural difficulties. Six boys with haemophilia and ICH and 11 controls (mean age: 7 years; range: 4-12 years) were assessed. Children with ICH were significantly more likely to have problems with motor function and visual motor integration (Fisher's exact: P < 0.05). In addition, they had a tendency towards more problems with strengths and difficulties than their peer group (Fisher's exact: P = 0.06). Five of the six boys who had sustained an ICH were in mainstream schools; four requiring assistance with their education. The results of this small study suggest that ICH may signify long-term consequences for boys with haemophilia. The multidisciplinary team need to be aware of the rare but potentially important impact on motor function, visual motor integration and behaviour, which may inhibit the child from functioning optimally. An agreed comprehensive battery of assessments in collaboration with schools and healthcare workers is required to identify impairments to enable prompt interventions to be co-ordinated.

Finding consensus on the physiotherapy management of asymptomatic infants with cystic fibrosis.

BACKGROUND: Babies with cystic fibrosis diagnosed by neonatal screening often display no overt signs of respiratory disease. The role of traditional routine daily chest physiotherapy in this particular group of babies is unclear and has generated considerable international debate. There is currently no evidence addressing this issue and present circumstances preclude a rigorous trial in the UK. This study aimed to provide expert consensus regarding the physiotherapy management of asymptomatic infants with CF. METHOD: A Delphi consensus method was used to gather and refine expert opinions of senior paediatric physiotherapists in the UK. Agreement was sought on 16 statements reflecting aspects of physiotherapy management in 'asymptomatic' babies with cystic fibrosis. RESULTS: Twenty-five senior paediatric physiotherapists from Specialist CF Centres throughout the UK participated in the study. Consensus was high amongst the respondents for 15 of the 16 statements. One statement failed to reach consensus. This related to the question of not routinely initiating a daily chest physiotherapy regimen in apparently healthy babies. Due to the lack of consensus an amendment to this statement was made, to allow a more flexible approach, where physiotherapists would not be obliged to initiate routine daily treatment in asymptomatic babies with CF, if they felt other another approach was justified. CONCLUSION: There was high consensus of opinion amongst senior physiotherapists in the UK on most aspects of the physiotherapy management of babies with CF. Consensus could not be achieved on whether routine daily chest physiotherapy is necessary in 'asymptomatic' babies. An agreed amendment to the original statement allows professionals to modify or change traditional practice with the sanction of their senior colleagues. The results of this process will be used by the Association of Chartered Physiotherapists in Cystic Fibrosis to form the basis of national clinical guidelines.

Can early subclinical gait changes in children with haemophilia be identified using the GAITRite walkway.

Development of haemophilic arthropathy has long-term implications for functional mobility in people with haemophilia, but early manifestations are often asymptomatic and difficult to identify. Earlier identification of joint damage may improve outcomes. The aim of this case note review was to determine whether the GAITRite system (electronic pressure sensitive walkway) could identify early changes in gait patterns in boys with haemophilia compared with their peers. Clinic data from medical and physiotherapy notes of boys with severe haemophilia were compared with data from age and leg length-matched controls. Data from two consecutive walks at preferred speed were collected on all participants using the GAITRite system. Clinic assessment notes from 26 boys (aged 7-17 years) with severe haemophilia were identified. Of these, 20 boys had no evidence of joint pathology on assessment and six boys had radiographic evidence of arthropathy. When these data were compared with normal controls, there were statistically significant increases in swing time, stance time, single support and double support in the asymptomatic group (P < 0.01) suggesting subtle early compensatory changes in gait pattern. The children with arthropathy had additional significant differences in their gait compared with matched controls. These differences included normalized velocity, step length, stride length, step time and base of support (P < 0.01). The GAITRite system appears sensitive enough to identify early subtle changes in gait and differentiate between asymptomatic boys with haemophilia and those with arthropathy in comparison with a matched control group. The electronic walkway is an accessible and portable means of providing quantitative gait analysis in the clinical environment. This is an important finding as early identification of gait changes may provide clinicians with the opportunity to intervene with the aim of arresting progression of joint damage.

Simultaneous measurement of force and respiratory profiles during chest physiotherapy in ventilated children.

There are currently no objective means of quantifying chest wall vibrations during manual physiotherapy. The aims of the study were to (i) develop a method to quantify physiotherapy-applied forces and simultaneous changes in respiratory flow and pressure, (ii) assess the feasibility of using this method in ventilated children and (iii) characterize treatment profiles delivered by physiotherapists in the paediatric intensive care unit. Customized sensing mats were designed and used in combination with a respiratory profile monitor. Software was developed to align force and flow data streams. Force and respiratory data were successfully collected in 55 children (median age 1.6 years (range 0.02-13.7 years)). Physiotherapists demonstrated distinctive variations in the pattern of force applied and manual lung inflations. The maximum applied force ranged from 15 to 172 N, and was correlated with the child's age (r = 0.76). Peak expiratory flow increased significantly during manual inflations both with and without chest wall vibrations (p < 0.05). This method provides the basis for objective assessments of the direct and independent effects of vibration forces and manual lung inflations as an essential precursor to developing evidence-based practice.

Conventional chest physiotherapy compared to other airway clearance techniques for cystic fibrosis.

BACKGROUND: Cystic fibrosis is an inherited life-limiting disorder, characterised by pulmonary infections and thick airway secretions. Chest physiotherapy has been integral to clinical management in facilitating removal of airway secretions. Conventional chest physiotherapy techniques (CCPT) have depended upon assistance during treatments, while more contemporary airway clearance techniques are self-administered, facilitating independence and flexibility. OBJECTIVES: To compare CCPT with other airway clearance techniques in terms of their effects on respiratory function, individual preference, adherence, quality of life and other outcomes. SEARCH STRATEGY: We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group trials register which comprises references identified from comprehensive electronic database searches and handsearching of relevant journals and abstract books of conference proceedings. We also searched CINAHL from 1982 to 2002 and AMED from 1985 to 2002. Date of most recent search: January 2004. SELECTION CRITERIA: Randomised or quasi-randomised clinical trials including those with a cross-over design where CCPT was compared with other airway clearance techniques. Studies of less than seven days duration were excluded. DATA COLLECTION AND ANALYSIS: Two reviewers allocated quality scores to relevant studies and independently extracted data. If we were unable to extract data, we invited authors to submit their data. We excluded studies from meta-analysis when data were lost or study design precluded comparison. For some continuous outcomes, we used the generic inverse variance method for meta-analysis of data from cross-over trials and data from parallel-designed trials were incorporated for comparison. We also examined efficacy of specific techniques and effects of treatment duration. MAIN RESULTS: Seventy-eight publications were identified by the searches. Twenty-nine of these were included, representing 15 data sets with 475 participants. There was no difference between CCPT and other airway clearance techniques in terms of respiratory function measured by standard lung function tests. Studies undertaken during acute exacerbations demonstrated relatively large gains in respiratory function irrespective of airway clearance technique. Longer-term studies demonstrated smaller improvements or deterioration over time. Ten studies reported individual preferences for technique, with participants tending to favour self-administered techniques. Heterogeneity in the measurement of preference precluded these data from meta-analysis. AUTHORS' CONCLUSIONS: This review demonstrated no advantage of CCPT over other airway clearance techniques in terms of respiratory function. There was a trend for participants to prefer self-administered airway clearance techniques. Limitations of this review included a paucity of well-designed, adequately-powered, long-term trials.

Effect of delayed sternal closure after cardiac surgery on respiratory function in ventilated infants.

OBJECTIVE: Studies examining the effect of sternal closure on respiratory function have not been published, and currently there is little evidence to guide ventilation management immediately after closure. The aim of this study was to establish the impact of delayed sternal closure on expired tidal volume, respiratory system compliance, and CO2 elimination immediately after the procedure in infants who had undergone open heart surgery. DESIGN: Prospective study of respiratory function before and after delayed sternal closure. SETTING: Cardiac intensive care unit, Great Ormond Street Hospital, London. PATIENTS: Seventeen infants (median age, 2 wks) with open median sternotomy incisions after cardiac surgery. Data were collected between August 1998 and March 2000. INTERVENTIONS: Respiratory function was measured continuously for 30 mins before and after delayed sternal closure in paralyzed ventilated infants. MEASUREMENTS AND RESULTS: Four babies were excluded from the study because they required either immediate increase in ventilation after delayed sternal closure (n = 3) or removal of pericardial blood collection (n = 1). In the remaining 13 infants, expired tidal volume and CO2 elimination decreased significantly (p < .005) by a mean of 17% and 29%, respectively, after sternal closure. In five of the remaining 13 patients, the magnitude of tracheal tube leak increased by > or = 10% after delayed sternal closure, thereby invalidating recorded changes in respiratory system compliance. Of the eight infants in whom there was a minimal change in leak, respiratory system compliance decreased significantly (p < .05) by a mean of 19%. CONCLUSIONS: This study supports the hypothesis that respiratory function may be compromised after delayed sternal closure and that ventilatory support should be increased to counteract the anticipated decrease in tidal volume. Extra vigilance should be applied in monitoring blood gases after delayed sternal closure to assess clinical responses to sternal closure or changes in ventilatory support. Accurate assessment of change in respiratory system compliance after any therapeutic intervention may be precluded by changes in tracheal tube leak during the procedure.

Maternal and fetal outcomes in pregnancies affected by von Willebrand disease type 2.

We report a case series that lends support for both the maternal and neonatal safety of vaginal delivery in pregnancies complicated by heritable von Willebrand disease types 2A and 2B. With proper hematologic support, a cesarean delivery may be indicated only for obstetric reasons.

The influence of endotracheal tube leak on the assessment of respiratory function in ventilated children.

OBJECTIVE: The use of respiratory mechanics to optimise ventilator settings has become more common since the integration of pressure and flow transducers into modern ventilators. However, values of respiratory resistance (R(rs)) and compliance (C(rs)) can be overestimated in the presence of tracheal tube leak and clinical decisions based on these figures would be misinformed. This study aimed to assess the influence of tracheal tube leak on measurements of C(rs), R(rs) and expired tidal volume (V(TE)) in ventilated children in order to establish when such measurements were reliable in this population. DESIGN: Respiratory function was monitored for at least five consecutive hours during which normal medical procedures were performed. The magnitude and variability of tracheal tube leak was assessed during these periods. SETTING: The paediatric and cardiac intensive care units at Great Ormond Street Hospital for Children, NHS Trust, London. PATIENTS: Seventy-five paralysed, fully ventilated infants and children. RESULTS: Ten children had a mean leak greater than 20% (range: 22%-65%). Amongst this group there were wide fluctuations with respect to leak magnitude, V(TE), C(rs) and R(rs). Leaks of less than 20% appeared necessary to obtain reliable measurements of C(rs) and R(rs) and to ensure consistent and adequate ventilation. CONCLUSIONS: Leaks larger than 20% result in inconsistent tidal volume delivery and gross overestimation of C(rs) and R(rs) irrespective of ventilation mode. The magnitude of tracheal tube leak needs to be accurately displayed on all ventilatory equipment to verify reliable measures of respiratory function so that appropriate clinical decisions can be made and ventilatory management optimised.