Orthodontic and Facial Characteristics of Craniofacial Syndromic Children with Obstructive Sleep Apnea

Introduction: Obstructive sleep apnea (OSA) is a disorder in which ventilation becomes disrupted due to a complete or partial upper airway obstruction Altered craniofacial morphology is one of the most important anatomical factors associated with obstructive sleep apnea (OSA). Studies have assessed craniofacial features in the non-syndromic pediatric population. The aim of this study was to analyze the orthodontic and facial characteristic of craniofacial syndromic children referred for polysomnography (PSG) and to assess the correlation with the apnea-hypopnea index (AHI). Methods: In the current cross-sectional study, consecutive syndromic patients referred for PSG were invited to participate. A systematic clinical examination including extra- and intra-oral orthodontic examination was performed by calibrated orthodontists. Standardized frontal and profile photographs with reference points were taken and analyzed using ImageJ^® software to study the craniofacial morphology. PSG data were analyzed for correlation with craniofacial features. STROBE guidelines were strictly adopted during the research presentation. Results: The sample included 52 syndromic patients (50% females, mean age 9.38 ± 3.36 years) diagnosed with 17 different syndromes, of which 24 patients had craniofacial photography analysis carried out. Most of the sample (40%) had severe OSA, while only 5.8% had no OSA. Down's syndrome (DS) was the most common syndrome (40%) followed by Goldenhar syndrome (5%), Pierre Robin Sequence (5%), and other syndromes. The severity of AHI was significantly correlated with decreased midfacial height. increased thyromental angle and cervicomental angle, decreased mandibular angle, and decreased upper facial height. All patients with DS were diagnosed with OSA (57% severe OSA), and their ODI was significantly correlated with increased intercanthal distance. Obesity was not correlated to the severity of AHI for syndromic patients. Conclusions: Decreased midfacial height and obtuse thyromental angle were correlated with increased AHI for syndromic patients. Increased intercanthal distance of DS patients could be a major predictor of OSA severity. Obesity does not seem to play a major role in the severity of OSA for syndromic patients. Further studies with larger samples are necessary to confirm these findings.

Chronic tracheostomy care of ventilator-dependent and -independent children: Clinical practice patterns of pediatric respirologists in a publicly funded (Canadian) healthcare system

OBJECTIVES

To describe the current clinical practice patterns of Canadian pediatric respirologists at pediatric tertiary care institutions regarding chronic tracheostomy tube care and management of home invasive ventilation.

METHODS

A pediatric respirologist/pediatrician with expertise in tracheostomy tube care and home ventilation was identified at each Canadian pediatric tertiary care center to complete a 59-item survey of multiple choice and short answer questions. Domains assessed included tracheostomy tube care, caregiver competency and home monitoring, speaking valves, medical management of tracheostomy complications, decannulation, and long-term follow-up.

RESULTS

The response rate was 100% (17/17) with all Canadian tertiary care pediatric centers represented and heterogeneity of practice was observed in all domains assessed. For example, though most centers employ Bivona™ (17/17) and Shiley™ (15/17) tracheostomy tubes, variability was observed around tube change, re-use, and cleaning practices. Most centers require two trained caregivers (14/17) and recommend 24/7 eyes on care and oxygen saturation monitoring. Discharge with an emergency tracheostomy kit was universal (17/17). Considerable heterogeneity was observed in the timing and use of speaking valves and speech-language assessment. Inhaled anti-pseudomonal antibiotics are employed by most centers (16/17) though the indication, agent, and protocol varied by center. Though decannulation practices varied considerably, the requirement of upper airway patency was universally required to proceed with decannulation (17/17) independent of ongoing ventilatory support requirements.

CONCLUSION

Considerable variability in pediatric tracheostomy tube care practice exists across Canada. These results will serve as a starting point to standardize and evaluate tracheostomy tube care nationally.

Socioeconomic inequalities in pediatric obstructive sleep apnea

STUDY OBJECTIVES

To examine the association between multiple measures of socioeconomic status (SES) and objectively measured obstructive sleep apnea (OSA) in a Canadian pediatric population.

METHODS

This was a cross-sectional study of 188 children (4-17 years, mean age 9.3 ± 3.5 years) prospectively recruited from two hospital sleep clinics in Canada, using multivariable-adjusted linear and logistic regression of five measures of SES including parental education, income, social class, geographic location, and perceived SES based on the MacArthur Scale of Subjective Social Status, assessed in relation to four polysomnographic OSA variables including apnea-hypopnea index, apnea index, mean oxygen saturation level, and oxygen desaturation index.

RESULTS

Overall, low household-level SES appeared to be associated with both frequency (apnea index ≥ 1 events/h) and severity (apnea-hypopnea index ≥ 5 events/h) of OSA in children, with maternal education showing the most consistent and significant associations. Specifically, children with mothers reporting less than high school education had nearly three times the odds of having OSA after controlling factors including body mass index (odds ratio 2.96 [95% confidence interval, 1.05-8.37]), compared to university-educated participants. Consistent associations were also observed for geographic location with less frequency and severity of OSA among nonurban children. Perceived SES was minimally inversely associated with our outcomes.

CONCLUSIONS

This cross-sectional, multicenter study demonstrated that SES factors are linked to the occurrence and severity of OSA in children. Results indicated the need to incorporate the screening of SES in the diagnostic process of pediatric OSA to provide more targeted intervention and patient-centered care.

CITATION

Park JW, Hamoda MM, Almeida FR, et al. Socioeconomic inequalities in pediatric obstructive sleep apnea. J Clin Sleep Med. 2022;18(2):637-645.

Death and Dying in Hospitalized Pediatric Patients: A Prospective Multicenter, Multinational Study

Background: For hospitalized children admitted outside of a critical care unit, the location, mode of death, "do-not-resuscitate" order (DNR) use, and involvement of palliative care teams have not been described across high-income countries. Objective: To describe location of death, patient and terminal care plan characteristics of pediatric inpatient deaths inside and outside the pediatric intensive care unit (PICU). Design: Secondary analysis of inpatient deaths in the Evaluating Processes of Care and Outcomes of Children in Hospital (EPOCH) randomized controlled trial. Setting/Subjects: Twenty-one centers from Canada, Belgium, the United Kingdom, Ireland, Italy, the Netherlands, and New Zealand. Measurement: Descriptive statistics were used to compare patient and terminal care plan characteristics. A multivariable generalized estimating equation examined if palliative care consult during hospital admission was associated with location of death. Results: A total of 365 of 144,539 patients enrolled in EPOCH died; 219 (60%) died in PICU and 143 (40%) died on another inpatient unit. Compared with other inpatient wards, patients who died in PICU were less likely to be expected to die, have a DNR or palliative care consult. Hospital palliative care consultation was more common in older children and independently associated with a lower adjusted odds (95% confidence interval) of dying in PICU [0.59 (0.52-0.68)]. Conclusion: Most pediatric inpatient deaths occur in PICU where patients were less likely to have a DNR or palliative care consult. Palliative care consultation could be better integrated into end-of-life care for younger children and those dying in PICU.

Trametinib therapy for children with neurofibromatosis type 1 and life-threatening plexiform neurofibroma or treatment-refractory low-grade glioma

Purpose

To describe a series of children with extensive PNF or treatment refractory PLGG treated on a compassionate basis with trametinib.

Methods

We report on six patients with NF‐1 treated with trametinib on a compassionate basis at British Columbia Children's Hospital since 2017. Data were collected retrospectively from the patient record. RAPNO and volumetric criteria were used to evaluate the response of intracranial and extracranial lesions, respectively.

Results

Subjects were 21 months to 14 years old at the time of initiation of trametinib therapy and 3/6 subjects are male. Duration of therapy was 4–28 months at the time of this report. All patients had partial response or were stable on analysis. Two patients with life‐threatening PNF had a partial radiographic response in tandem with significant clinical improvement and developmental catch up. One subject discontinued therapy after 6 months due to paronychia and inadequate response. The most common adverse effect (AE) was grade 1–2 paronychia or dermatitis in 5/6 patients. There were no grade 3 or 4 AEs. At the time of this report, five patients remain on therapy.

Conclusion

Trametinib is an effective therapy for advanced PNF and refractory PLGG in patients with NF‐1 and is well tolerated in children. Further data and clinical trials are required to assess tolerance, efficacy and durability of response, and length of treatment required in such patients.

NFB-12. TRAMETINIB THERAPY FOR PEDIATRIC PATIENTS WITH REFRACTORY LOW GRADE GLIOMA OR EXTENSIVE SYMPTOMATIC PLEXIFORM NEUROFIBROMA

OBJECTIVE

Refractory symptomatic plexiform neurofibromas (PNF) and inoperable refractory low grade gliomas (LGG) pose a clinical challenge that may be life threatening. Phase 1 and 2 clinical trials of MEK inhibition with selumetinib in inoperable PNF and LGG have demonstrated promising results in pediatrics, however access has been limited to enrollment on clinical trial. Phase 1 clinical trial for trametinib a MEK 1 and 2 inhibitor has been completed, publication is pending. Thus we have treated a series of children on a compassionate basis with extensive PN or LGG refractory disease with trametinib, as this is available in Canada.

METHODS

We have treated children with trametinib on a compassionate basis in our province since 2017. Review of the clinical data regarding this therapy has been IRB approved.

RESULTS

Two young patients were treated for indication of life threatening extensive PNF and have had tumor shrinkage and improvement of clinical status. Treatment has been complicated by paronychiae, eczema exacerbation, chondrodermatitis nodularis helicis, RSV and influenza B infection and CTCAE grade 2 pneumonia. In spite of the side effects these two patients remain on treatment due to clear benefit from therapy including: improved respiratory compromise, hearing and dysphagia. We will present the data of additional patients treated with trametinib.

CONCLUSION

Trametinib is an effective therapy for life threatening PNF by changing the natural history of tumor growth in young children. Further data is required in terms of tolerance, efficacy and durability of response in such patients in the setting of clinical trials.

Implementation study of a 5-component pediatric early warning system (PEWS) in an emergency department in British Columbia, Canada, to inform provincial scale up

Background

The rapid identification of deterioration in the pediatric population is complex, particularly in the emergency department (ED). A comprehensive multi-faceted Pediatric Early Warning System (PEWS) might maximize early recognition of clinical deterioration and provide a structured process for the reassessment and escalation of care. The objective of the study was to evaluate the implementation fidelity, effectiveness, and utility of a 5-component PEWS implemented in the ED of an urban public general hospital in British Columbia, Canada, and to guide provincial scale up.

Methods

We used a before-and-after design to evaluate the implementation fidelity, effectiveness, and utility of a 5-component PEWS (pediatric assessment flowsheet, PEWS score, situational awareness, escalation aid, and communication framework). Sources of data included patient medical records, surveys of direct care staff, and key-informant interviews. Data were analyzed using mixed-methods approaches.

Results

The majority of medical records had documented PEWS scores at triage (80%) and first bedside assessment (81%), indicating that the intervention was implemented with high fidelity. The intervention was effective in increasing vital signs documentation, both at first beside assessment (84% increase) and throughout the ED stay (> 100% increase), in improving staff’s self-perceived knowledge and confidence in providing pediatric care, and self-reported communication between staff. Satisfaction levels were high with the PEWS scoring system, flowsheet, escalation aid, and to a lesser extent with the situational awareness tool and communication framework. Reasons for dissatisfaction included increased paperwork and incidence of false-positives. Overall, the majority of providers indicated that implementation of PEWS and completing a PEWS score at triage alongside the Canadian Triage and Acuity Scale (CTAS) added value to pediatric care in the ED. Results also suggest that the intervention is aligned with current practice in the ED.

Conclusion

Our study shows that high-fidelity implementation of PEWS in the ED is feasible. We also show that a multi-component PEWS can be effective in improving pediatric care and be well-accepted by staff. Results and lessons learned from this pilot study are being used to scale up implementation of PEWS in ED settings across the province of British Columbia.

Pediatric pulse oximetry-based OSA screening at different thresholds of the apnea-hypopnea index with an expression of uncertainty for inconclusive classifications

BACKGROUND

Assessments of pediatric obstructive sleep apnea (OSA) are underutilized across Canada due to a lack of resources. Polysomnography (PSG) measures OSA severity through the average number of apnea/hypopnea events per hour (AHI), but is resource intensive and requires a specialized sleep laboratory, which results in long waitlists and delays in OSA detection. Prompt diagnosis and treatment of OSA are crucial for children, as untreated OSA is linked to behavioral deficits, growth failure, and negative cardiovascular consequences. We aim to assess the performance of a portable pediatric OSA screening tool at different AHI cut-offs using overnight smartphone-based pulse oximetry.

MATERIAL AND METHODS

Following ethics approval and informed consent, children referred to British Columbia Children's Hospital for overnight PSG were recruited for two studies including 160 and 75 children, respectively. An additional smartphone-based pulse oximeter sensor was used in both studies to record overnight pulse oximetry [SpO₂ and photoplethysmogram (PPG)] alongside the PSG. Features characterizing SpO₂ dynamics and heart rate variability from pulse peak intervals of the PPG signal were derived from pulse oximetry recordings. Three multivariate logistic regression screening models, targeted at three different levels of OSA severity (AHI ≥ 1, 5, and 10), were developed using stepwise-selection of features using the Bayesian information criterion (BIC). The "Gray Zone" approach was also implemented for different tolerance values to allow for more precise detection of children with inconclusive classification results.

RESULTS

The optimal diagnostic tolerance values defining the "Gray Zone" borders (15, 10, and 5, respectively) were selected to develop the final models to screen for children at AHI cut-offs of 1, 5, and 10. The final models evaluated through cross-validation showed good accuracy (75%, 82% and 89%), sensitivity (80%, 85% and 82%) and specificity (65%, 79% and 91%) values for detecting children with AHI ≥ 1, AHI ≥ 5 and AHI ≥ 10. The percentage of children classified as inconclusive was 28%, 38% and 16% for models detecting AHI ≥ 1, AHI ≥ 5, and AHI ≥ 10, respectively.

CONCLUSIONS

The proposed pulse oximetry-based OSA screening tool at different AHI cut-offs may assist clinicians in identifying children at different OSA severity levels. Using this tool at home prior to PSG can help with optimizing the limited resources for PSG screening. Further validation with larger and more heterogeneous datasets is required before introducing in clinical practice.

Effect of a Pediatric Early Warning System on All-Cause Mortality in Hospitalized Pediatric Patients: The EPOCH Randomized Clinical Trial

IMPORTANCE

There is limited evidence that the use of severity of illness scores in pediatric patients can facilitate timely admission to the intensive care unit or improve patient outcomes.

OBJECTIVE

To determine the effect of the Bedside Paediatric Early Warning System (BedsidePEWS) on all-cause hospital mortality and late admission to the intensive care unit (ICU), cardiac arrest, and ICU resource use.

DESIGN, SETTING, AND PARTICIPANTS

A multicenter cluster randomized trial of 21 hospitals located in 7 countries (Belgium, Canada, England, Ireland, Italy, New Zealand, and the Netherlands) that provided inpatient pediatric care for infants (gestational age ≥37 weeks) to teenagers (aged ≤18 years). Participating hospitals had continuous physician staffing and subspecialized pediatric services. Patient enrollment began on February 28, 2011, and ended on June 21, 2015. Follow-up ended on July 19, 2015.

INTERVENTIONS

The BedsidePEWS intervention (10 hospitals) was compared with usual care (no severity of illness score; 11 hospitals).

MAIN OUTCOMES AND MEASURES

The primary outcome was all-cause hospital mortality. The secondary outcome was a significant clinical deterioration event, which was defined as a composite outcome reflecting late ICU admission. Regression analyses accounted for hospital-level clustering and baseline rates.

RESULTS

Among 144 539 patient discharges at 21 randomized hospitals, there were 559 443 patient-days and 144 539 patients (100%) completed the trial. All-cause hospital mortality was 1.93 per 1000 patient discharges at hospitals with BedsidePEWS and 1.56 per 1000 patient discharges at hospitals with usual care (adjusted between-group rate difference, 0.01 [95% CI, -0.80 to 0.81 per 1000 patient discharges]; adjusted odds ratio, 1.01 [95% CI, 0.61 to 1.69]; P = .96). Significant clinical deterioration events occurred during 0.50 per 1000 patient-days at hospitals with BedsidePEWS vs 0.84 per 1000 patient-days at hospitals with usual care (adjusted between-group rate difference, -0.34 [95% CI, -0.73 to 0.05 per 1000 patient-days]; adjusted rate ratio, 0.77 [95% CI, 0.61 to 0.97]; P = .03).

CONCLUSIONS AND RELEVANCE

Implementation of the Bedside Paediatric Early Warning System compared with usual care did not significantly decrease all-cause mortality among hospitalized pediatric patients. These findings do not support the use of this system to reduce mortality.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01260831.

Clinician-Driven Design of VitalPAD-An Intelligent Monitoring and Communication Device to Improve Patient Safety in the Intensive Care Unit

The pediatric intensive care unit (ICU) is a complex environment, in which a multidisciplinary team of clinicians (registered nurses, respiratory therapists, and physicians) continually observe and evaluate patient information. Data are provided by multiple, and often physically separated sources, cognitive workload is high, and team communication can be challenging. Our aim is to combine information from multiple monitoring and therapeutic devices in a mobile application, the VitalPAD, to improve the efficiency of clinical decision-making, communication, and thereby patient safety. We observed individual ICU clinicians, multidisciplinary rounds, and handover procedures for 54 h to identify data needs, workflow, and existing cognitive aid use and limitations. A prototype was developed using an iterative participatory design approach; usability testing, including general and task-specific feedback, was obtained from 15 clinicians. Features included map overviews of the ICU showing clinician assignment, patient status, and respiratory support; patient vital signs; a photo-documentation option for arterial blood gas results; and team communication and reminder functions. Clinicians reported the prototype to be an intuitive display of vital parameters and relevant alerts and reminders, as well as a user-friendly communication tool. Future work includes implementation of a prototype, which will be evaluated under simulation and real-world conditions, with the aim of providing ICU staff with a monitoring device that will improve their daily work, communication, and decision-making capacity. Mobile monitoring of vital signs and therapy parameters might help improve patient safety in wards with single-patient rooms and likely has applications in many acute and critical care settings.

Caregiver knowledge and skills to safely care for pediatric tracheostomy ventilation at home

OBJECTIVE

Caregivers of children using home mechanical ventilation (HMV) via tracheostomy require appropriate knowledge and skills. Existing training curricula are locally developed and content variable. We sought to develop a competency checklist to inform initial training and subsequent assessment of knowledge and skills of family caregivers.

METHODS

We used a 2-step process. Candidate items were generated by synthesis of a scoping review, existing checklists, with additional items suggested by an eight member inter-professional group representing pediatric HMV programs across Canada. Following removal of duplicate items, we conducted a three-round Delphi to gain consensus on items for the KidsVent Checklist.

RESULTS

The scoping review and checklists from five HMV programs identified 18 domains and 172 items; one additional domain and 83 additional items were identified by our expert group who also classified domains as mandatory or optional. We recruited 95 clinicians representing 12 Canadian paediatric HMV programs to participate in Delphi round 1 (response rate 72%; 84%, and 100% for subsequent rounds). Importance rating of the 255 items reduced them to 246 items. In the final checklist, the 19 domains comprised 14 mandatory (189 mandatory items) and 5 optional domains (57 optional items).

CONCLUSIONS

We have developed the KidsVent checklist using rigorous consensus building methods, informed by participants with diverse geographic and inter-professional representation. This checklist represents knowledge and skills required to safely care for children using tracheostomy ventilation at home. Further study is required to explore the impact of this checklist on outcomes of this growing group of technology-dependent children.

Pulse oximetry recorded from the Phone Oximeter for detection of obstructive sleep apnea events with and without oxygen desaturation in children

Obstructive sleep apnea (OSA) disrupts normal ventilation during sleep and can lead to serious health problems in children if left untreated. Polysomnography, the gold standard for OSA diagnosis, is resource intensive and requires a specialized laboratory. Thus, we proposed to use the Phone Oximeter™, a portable device integrating pulse oximetry with a smartphone, to detect OSA events. As a proportion of OSA events occur without oxygen desaturation (defined as SpO2 decreases ≥ 3%), we suggest combining SpO2 and pulse rate variability (PRV) analysis to identify all OSA events and provide a more detailed sleep analysis. We recruited 160 children and recorded pulse oximetry consisting of SpO2 and plethysmography (PPG) using the Phone Oximeter™, alongside standard polysomnography. A sleep technician visually scored all OSA events with and without oxygen desaturation from polysomnography. We divided pulse oximetry signals into 1-min signal segments and extracted several features from SpO2 and PPG analysis in the time and frequency domain. Segments with OSA, especially the ones with oxygen desaturation, presented greater SpO2 variability and modulation reflected in the spectral domain than segments without OSA. Segments with OSA also showed higher heart rate and sympathetic activity through the PRV analysis relative to segments without OSA. PRV analysis was more sensitive than SpO2 analysis for identification of OSA events without oxygen desaturation. Combining SpO2 and PRV analysis enhanced OSA event detection through a multiple logistic regression model. The area under the ROC curve increased from 81% to 87%. Thus, the Phone Oximeter™ might be useful to monitor sleep and identify OSA events with and without oxygen desaturation at home.

The quality of life of home-ventilated children and their primary caregivers plus the associated social and economic burdens: a prospective study

BACKGROUND

Despite the obvious challenges faced by families caring for children on home ventilation, there is surprisingly little research into the details of their daily lives. In particular, little is known about the quality of life of the child and caregiver plus the associated social and economic burdens of care.

METHODS

We prospectively studied 90 families enrolled in a paediatric home ventilation service in British Columbia. In the clinic, we recorded demographic information, patient acuity score and quality of life for patient and caregiver using standardised questionnaires. Parents then monitored social and financial costs of care at home over the subsequent 8 weeks. These data were collected by telephone at 1 and 2 months.

RESULTS

Most children led rich active lives. Camping trips, wheelchair sports and foreign travel were the norm, not the exception. Over 90% assessed the burden of care as mild or moderate. Government support covers medical expenses and home nursing (median 32 h/week, IQR 0-62.5 h). Monthly unreimbursed family expenses were low (median $87.7, IQR $15.3-$472). Despite this, nearly 25% of primary caregivers assessed burden of care as severe and over 50% had chronic illnesses requiring daily medication (principally depression, anxiety and arthritis). Quality of life for children or caregivers did not correlate with income or education.

INTERPRETATION

Home ventilation of complex children is a successful strategy but it places significant strain on the primary caregiver. Specific attention to the physical and mental health of the caregiver should be an integral part of the management of home-ventilated children.

TRIAL REGISTRATION NUMBER

NCT01863992.

Steroids in fluid and/or vasoactive infusion dependent pediatric shock: study protocol for a randomized controlled trial

Background

Physicians often administer corticosteroids for the treatment of fluid and vasoactive infusion dependent pediatric shock. This use of corticosteroids is controversial, however, and has never been studied in a pediatric randomized controlled trial (RCT). This pilot trial will determine the feasibility of a larger RCT on the role of corticosteroids in pediatric shock.

Methods/design

Steroids in Fluid and/or Vasoactive Infusion Dependent Pediatric Shock (STRIPES) is a pragmatic, seven-center, double-blind, pilot RCT. We aim to randomize 72 pediatric patients with fluid and vasoactive infusion dependent shock to receive either hydrocortisone or a saline placebo for 7 days or until clinical stability, whichever occurs first. The primary outcome of this pilot trial is the feasibility of recruitment, defined as the number of patients enrolled over a 1-year period. Secondary outcomes include the frequency of, and reasons for, open-label steroid use, protocol adherence, incidence of mortality and corticosteroid-associated adverse events, time to discontinuation of inotropes, and feasibility of blood sampling.

Discussion

Corticosteroids are used for the treatment of pediatric shock without sufficient evidence to support this practice. While there is a scientific rationale and limited data supporting their use in this setting, there is also evidence from other populations suggesting potential harm. The STRIPES pilot study will assess the feasibility of a larger, much needed trial powered for clinically important outcomes.

Trial registration

ClinicalTrials.gov: NCT02044159

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-016-1365-6) contains supplementary material, which is available to authorized users.

Evaluation of cardiac modulation in children in response to apnea/hypopnea using the Phone Oximeter(™)

Individuals with sleep disordered breathing (SDB) can experience changes in automatic cardiac regulation as a result of frequent sleep fragmentation and disturbance in normal respiration and oxygenation that accompany most apnea/hypopnea events. In adults, these changes are reflected in enhanced sympathetic and reduced parasympathetic activity. In this study, we examined the autonomic cardiac regulation in children with and without SDB, through spectral and detrended fluctuation analysis (DFA) of pulse rate variability (PRV). PRV was measured from pulse-to-pulse intervals (PPIs) of the photoplethysmogram (PPG) recorded from 160 children using the Phone Oximeter(™) in the standard setting of overnight polysomnography. Spectral analysis of PRV showed the cardiac parasympathetic index (high frequency, HF) was lower (p < 0.01) and cardiac sympathetic indices (low frequency, LF and LF/HF ratio) were higher (p < 0.01) during apnea/hypopnea events for more than 95% of children with SDB. DFA showed the short- and long-range fluctuations of heart rate were more strongly correlated in children with SDB compared to children without SDB. These findings confirm that the analysis of the PPG recorded using the Phone Oximeter(™) could be the basis for a new screening tool for assessing PRV in non-clinical environment.

Casting a look at pediatric plastic bronchitis

OBJECTIVES

To review clinical presentations and management strategies for children with plastic bronchitis.

METHODS

Retrospective chart review.

RESULTS

Seven patients required rigid bronchoscopy to remove bronchial casts over a 17-year study period. Mean age at presentation was 60 months. Mean follow-up was 53 months. Co-morbidities included: congenital heart disease (n=3), chronic pulmonary disorders (n=2) and sickle cell disease (n=1). 4 patients required multiple bronchoscopies for recurrent casts. Adjunctive topical therapies were administered in all 7 patients, without complication. Rigid bronchoscopy for cast removal was performed in 2 patients who were on extra-corporal membrane oxygenation (ECMO), using special precautions to safeguard the ECMO catheters.

CONCLUSIONS

Bronchial casts in children may present acutely or sub-acutely. Recurrent casts are unusual; however, in combination with severe cardiac disease may lead to mortality. Adjunctive topical therapies are still under investigation. Special safeguards for ECMO catheters are imperative. This case series complements and adds to the International Plastic Bronchitis Registry.

Pulse rate variability compared with Heart Rate Variability in children with and without sleep disordered breathing

Heart Rate Variability (HRV), the variation of time intervals between heartbeats, is one of the most promising and widely used quantitative markers of autonomic activity. Traditionally, HRV is measured as the series of instantaneous cycle intervals obtained from the electrocardiogram (ECG). In this study, we investigated the estimation of variation in heart rate from a photoplethysmography (PPG) signal, called pulse rate variability (PRV), and assessed its accuracy as an estimate of HRV in children with and without sleep disordered breathing (SDB). We recorded raw PPGs from 72 children using the Phone Oximeter, an oximeter connected to a mobile phone. Full polysomnography including ECG was simultaneously recorded for each subject. We used correlation and Bland-Altman analysis for comparing the parameters of HRV and PRV between two groups of children. Significant correlation (r > 0.90, p < 0.05) and close agreement were found between HRV and PRV for mean intervals, standard deviation of intervals (SDNN) and the root-mean square of the difference of successive intervals (RMSSD). However Bland-Altman analysis showed a large divergence for LF/HF ratio parameter. In addition, children with SDB had depressed SDNN and RMSSD and elevated LF/HF in comparison to children without SDB. In conclusion, PRV provides the accurate estimate of HRV in time domain analysis but does not reflect precise estimation for parameters in frequency domain.

Oxygen saturation in children with and without obstructive sleep apnea using the phone-oximeter

Obstructive sleep apnea (OSA) in children can lead to daytime sleepiness, growth failure and developmental delay. Polysomnography (PSG), the gold standard to diagnose OSA is highly resource intensive and is confined to the sleep laboratory. In this study we propose to identify children with OSA using blood oxygen saturation (SpO2) obtained from the Phone Oximeter. This portable, in-home device is able to monitor patients over multiple nights, causes less sleep disturbance and facilitates a more natural sleep pattern. The proposed algorithm analyzes the SpO2 signal in the time and frequency domain using a 90-s sliding window. Three spectral parameters are calculated from the power spectral density (PSD) to evaluate the modulation in the SpO2 due to the oxyhemoblobin desaturations. The power P, slope S in the discriminant band (DB), and ratio R between P and total power are calculated for each window. Tendency and variability indices, number of SpO2 desaturations and time spent under 2% or 3% of baseline saturation level are computed for each time window. The statistical distribution of the temporal evolution of all parameters is analyzed to identify 68 children, 30 with OSA and 38 without OSA (nonOSA). This characterization was evaluated by a feature selection based on a linear discriminant. The combination of temporal and spectral parameters provided the best leave one out crossvalidation results with an accuracy of 86.8%, a sensitivity of 80.0%, and a specificity of 92.1% using only 5 parameters. The median of R, mean of P and S and mean and standard deviation of the number of desaturations below 3% of baseline saturation level, were the most representative parameters. Hence, a better knowledge of SpO2 dynamics could help identifying children with OSA with the Phone Oximeter.

Bronchial balloon occlusion in children with complex pulmonary air leaks

Pulmonary air leaks in children are most commonly due to infection or barotrauma. While cases of severe barotrauma are falling because of advances in neonatal care, the incidence of necrotising pneumonia is rising. The majority of air leaks can be managed conservatively, but more severe cases pose a significant challenge to the clinician. The use of occlusive endobronchial balloons is an established anaesthetic technique for a number of indications, but is not widely used in children. We conducted a review over a 12-year period, and report six cases of complex air leaks in which balloon occlusion was used. Balloon occlusion was successful in both cases of bronchopleural fistulae (secondary to severe necrotising pneumonia) and half of the cases of intrapulmonary air leak (due to barotrauma). In the other two cases (due to barotrauma and filamin A deficiency), it was transiently effective. No serious adverse effects or complications were encountered. In selected cases, endobronchial balloons are a useful adjunct in the management of life-threatening bronchopleural fistulae and cystic lung disease. The procedure is non-operative, minimally invasive and reversible. With the increasing incidence of bronchopleural fistulae, this may become an increasingly important therapy.

Multicentre validation of the bedside paediatric early warning system score: a severity of illness score to detect evolving critical illness in hospitalised children

Introduction

The timely provision of critical care to hospitalised patients at risk for cardiopulmonary arrest is contingent upon identification and referral by frontline providers. Current approaches require improvement. In a single-centre study, we developed the Bedside Paediatric Early Warning System (Bedside PEWS) score to identify patients at risk. The objective of this study was to validate the Bedside PEWS score in a large patient population at multiple hospitals.

Methods

We performed an international, multicentre, case-control study of children admitted to hospital inpatient units with no limitations on care. Case patients had experienced a clinical deterioration event involving either an immediate call to a resuscitation team or urgent admission to a paediatric intensive care unit. Control patients had no events. The scores ranged from 0 to 26 and were assessed in the 24 hours prior to the clinical deterioration event. Score performance was assessed using the area under the receiver operating characteristic (AUCROC) curve by comparison with the retrospective rating of nurses and the temporal progression of scores in case patients.

Results

A total of 2,074 patients were evaluated at 4 participating hospitals. The median (interquartile range) maximum Bedside PEWS scores for the 12 hours ending 1 hour before the clinical deterioration event were 8 (5 to 12) in case patients and 2 (1 to 4) in control patients (P < 0.0001). The AUCROC curve (95% confidence interval) was 0.87 (0.85 to 0.89). In case patients, mean scores were 5.3 at 20 to 24 hours and 8.4 at 0 to 4 hours before the event (P < 0.0001). The AUCROC curve (95% CI) of the retrospective nurse ratings was 0.83 (0.81 to 0.86). This was significantly lower than that of the Bedside PEWS score (P < 0.0001).

Conclusions

The Bedside PEWS score identified children at risk for cardiopulmonary arrest. Scores were elevated and continued to increase in the 24 hours before the clinical deterioration event. Prospective clinical evaluation is needed to determine whether this score will improve the quality of care and patient outcomes.

Iatrogenic hyponatremia in hospitalized children: Can it be avoided?

Iatrogenic hyponatremia in hospitalized children is a common problem. It is usually caused by the administration of free water, either orally or through the prescription of hypotonic intravenous fluids. It can result in cerebral edema and death, and is most commonly reported in healthy children undergoing minor surgery. The current teachings and practical guidelines for maintenance fluid infusions are based on caloric expenditure data in healthy children that were derived and published more than 50 years ago. A re-evaluation of these data and more recent recognition that hospitalized children are vulnerable to hyponatremia, with its resulting morbidity and mortality rates, suggest that changes in paediatricians' approach to fluid administration are necessary. There is no single fluid therapy that is optimal for all hospitalized children. A thorough assessment of the type of fluid, volume of fluid and electrolyte requirements based on individual patient requirements, plus rigorous monitoring, is required in any child receiving intravenous fluids. The present article reviews how hyponatremia occurs and makes recommendations for minimizing the risk of iatrogenic hyponatremia.

Scientific responsibility for the dissemination and interpretation of genetic research: lessons from the "warrior gene" controversy

This paper discusses the announcement by a team of researchers that they identified a genetic influence for a range of "antisocial" behaviours in the New Zealand Māori population (dubbed the "warrior gene"). The behaviours included criminality, violence, gambling and alcoholism. The reported link between genetics and behaviour met with much controversy. The scientists were described as hiding behind a veneer of supposedly "objective" western science, using it to perpetuate "racist and oppressive discourses". In this paper we examine what went wrong in the dissemination of the research. We chose as our framework the debate around the "internal/external" responsibilities of scientists. Using this discourse we argue that when the researchers ventured to explain their research in terms of social phenomena, they assumed a duty to ensure that their findings were placed "in context". By "in context", we argue that evidence of any genetic influence on behavioural characteristics should not be reported in isolation, but instead presented alongside other environmental, cultural and socio-economic influences that may also contribute to the studied behaviour. Rather than imposing a new obligation on scientists, we find this duty to contextualise results is in keeping with the spirit of codes of ethics already in place. Lessons from the "warrior gene" controversy may assist researchers elsewhere to identify potential areas of conflict before they jeopardise research relationships, or disseminate findings in a manner that fuels misleading and/or potentially discriminatory attitudes in society.

How accurate is the diagnosis of exercise induced asthma among Vancouver schoolchildren?

BACKGROUND

Limited access to exercise testing facilities means that the diagnosis of exercise induced asthma (EIA) is mainly based on self-reported respiratory symptoms. This is open to error since the correlation between exercise related symptoms and subsequent exercise testing has been shown to be poor.

AIM

To study the accuracy of clinically diagnosed EIA among Vancouver schoolchildren.

METHODS

Fifty two children referred for investigation of poorly controlled EIA were studied. Following a careful history and physical examination, children performed pulmonary function tests before, then 5 and 15 minutes after a standardised treadmill exercise test. Based on overall assessment, a diagnostic explanation for each child's respiratory complaints was provided as far as possible.

RESULTS

Only eight children (15.4%) fulfilled diagnostic criteria for EIA (fall in FEV(1) > or =10%). Of the remainder: 12 (23.1%) were unfit, 14 (26.9%) had vocal cord dysfunction/sigh dyspnoea, 7 (13.5%) had a habit cough, and 11 (21.1%) had no abnormalities on clinical or laboratory testing, so were given no diagnosis. Initial reported symptoms of wheeze or cough often changed significantly following a careful history, particularly among the eight elite athletes. The final complaint was sometimes not respiratory, and, in a few cases, was not even associated with exercise.

CONCLUSIONS

The clinical diagnosis of EIA is inaccurate among Vancouver schoolchildren, principally due to the unreliability of their initial exercise related complaints. Symptom exaggeration, familiarity with medical jargon, and psychogenic complaints are all common. A careful history is essential in this population before basing any diagnosis on self-reported respiratory symptoms.

The Acute Dialysis Quality Initiative--part III: solute control (treatment dose)

One of the most important advances in chronic dialysis therapy was the establishment of a method for determining delivered dose. There has been a meaningful relationship between higher delivered dialysis dose and improved outcome in the end-stage renal disease (ESRD) patient. The question of establishing a similar dialysis dose method in the patients with acute renal failure (ARF) is hampered with several specific issues to the ARF patient. The state of catabolism in ARF is not eubolic, but rather catabolic. Patient volume or urea space is highly variable among ARF patients and even within the same patient over very short periods of time. Finally, there are comorbidities that play a major role in both the ultimate patient outcome and the generation of many of the indicators used in dialysis dose generation. Thus, the mere transition from the ESRD dose methodology, where these issues are quite stable, to the ARF population is not an easy process. It is, however, of utmost importance that a dose methodology be established. Only after will we be able to address the dose/outcome relationship. The current article reviews what is known, what is theorized and what needs to be established in an effort to determine a dialysis dose methodology in ARF patients.

Hyperbaric oxygen therapy for cerebral palsy: two complications of treatment

There is growing interest in the use of hyperbaric oxygen therapy (HBO(2)) for children with cerebral palsy. Although there is no rigorous evidence to support this management, private hyperbaric centers have been established throughout the United States and Canada. There is likely to be increasing pressure on pediatricians and other health professionals to prescribe HBO(2). We describe 2 children with cerebral palsy who suffered significant morbidity immediately after treatment with hyperbaric oxygen. Both the temporal association and pathologic findings suggest that the hyperbaric treatment is likely to have been responsible for the resulting complications. As with any new therapy, we suggest waiting for the results of a randomized, controlled trial before recommending this treatment.

Respirology manpower in Canada--A report for the Canadian Thoracic Society Education Committee

A report on adult and pediatric respirology manpower in Canada was prepared from data supplied by the Royal College of Physicians and Surgeons of Canada (RCPSC), and from program directors (and other colleagues) at universities across Canada. The data support a significant deficiency of adult respirologists in Canada, which is estimated to be from 10%, based on a 10-year-old outdated RCPSC recommendation, to 20%, based on equalization with the 'best' province, to as high as 50%, based on long waiting lists, particularly for respiratory sleep problems, and estimates obtained from academic centres across Canada. Although there are less data available for pediatric respirology, a similar approach suggests a 50% to 100% shortfall in pediatric respirologists. Output from Canadian training programs in adult and pediatric respirology is not likely to meet this need. We recommend that steps be taken urgently to provide sufficient resources for training adult and pediatric respirologists, and to ensure that funding is provided for subspecialist positions in the community.

Can peak expiratory flow be measured accurately during a forced vital capacity manoeuvre?

Spirometry and peak flow measurements traditionally depend on different forced expiratory manoeuvres and have usually been performed on separate, dedicated equipment. As spirometry becomes more widely used in primary care settings, the authors wished to determine whether there was a systematic difference between peak expiratory flow (PEF) derived from a short sharp exhalation (PEF manoeuvre) and from a full forced vital capacity (FVC) manoeuvre, using the same turbine spirometer (Microloop, Micro Medical, Kent, UK). Eighty children (38 with current asthma) aged 7-16 yrs were asked to perform 2 blocks of PEF and FVC manoeuvres, the order being randomly assigned. PEF obtained from a peak flow manoeuvre (PEFPF) was significantly greater than that from a forced vital capacity manoeuvre (PEFVC) in both healthy (group mean difference 20 L x min(-1); p<0.001) and asthmatic children (group mean difference 9 L.min(-1); p<0.004). For clinical purposes, a mean difference of about 3% for children with asthma is of no practical significance, and peak expiratory flow data can usefully be obtained during spirometric recordings.

Chronic cough and wheeze in children: do they all have asthma?

In the experience of both authors, children referred for investigation of a chronic productive cough often do not fit conventional diagnostic categories. The aim of this study was to answer two questions: 1) do such diagnostic orphans exist? and, 2) if so, can they be classified in a clinically useful manner? Eighty one previously undiagnosed children referred with a history of more than 3 months productive or rattly cough were studied prospectively. Investigations consisted of a detailed history, physical examination, and an extensive set of clinical investigations. Sixty randomly selected asthmatic children served as demographic controls. Children fell into three groups: 23 had newly diagnosed conditions, such as cystic fibrosis, or were indistinguishable from asthma; 24 had a history of major medical interventions (cardiac surgery, chemotherapy, tracheo-oesophageal fistula repair); 34 had a history of significant early respiratory tract infections, usually combined with poor social conditions. The latter group differed significantly from asthmatic controls in a wide range of demographic and clinical comparisons. Native American children were overrepresented. The results of this study suggest that early respiratory insults (whether viral or medical) can induce self-perpetuating inflammation, manifesting as a chronic productive cough and intermittent wheeze. The associations between poverty and infant chest infections or early invasive medical treatment with subsequent chronic respiratory disease are clearly definable and probably justify diagnostic terms distinct from asthma, particularly for use in epidemiological studies.

Heterogeneous Serratia marcescens genotypes from a nosocomial pediatric outbreak

OBJECTIVE

Define the applicability of a rapid molecular typing scheme to study the epidemiology of a Serratia marcescens outbreak.

DESIGN

With the assistance of a simple bacterial lysis technique, isolates of S marcescens from a putative outbreak were genotyped with the polymerase chain reaction technology for which primers were chosen on the basis of previously defined enterobacterial repetitive intergenic consensus sequences.

SETTING

Pediatric ICU.

PATIENTS

Intensively monitored patients who were found to yield S marcescens from any body site during the epidemic period.

RESULTS

Over an 8-month period, 12 ICU patients were either infected or colonized with S marcescens. All of these patients were transiently supported by artificial ventilation. During the epidemiologic investigation, a dilution error in a high-level glutaraldehyde disinfectant, which was being used for some ventilator components, was observed. Rectification of the error was associated with an abrupt termination of the outbreak. Enterobacterial repetitive intergenic consensus polymerase chain reaction was easily applicable to this setting and it defined 4 distinct genotypes among the 12 isolates.

CONCLUSION

The typing method is easily implemented and offers great promise as an epidemiologic tool. The associated investigation served to emphasize that an outbreak may occur with more than one epidemic strain and that strain heterogeneity itself does not exclude an outbreak.

Midazolam following open heart surgery in children: haemodynamic effects of a loading dose

Our objective was to establish the safety and effectiveness of a loading dose of midazolam for postoperative sedation of children recovering from open heart surgery; a prospective randomized placebo-controlled double-blind study was done with subjects randomized to three groups according to loading dose. I = 0.08 mg.kg-1; II = 0.04 mg.kg-1; and III = 0.00 mg.kg-1 (placebo). An open label continuous midazolam infusion protocol followed. Haemodynamic parameters were monitored. The study was discontinued following an adverse event involving the 23rd subject. When data for all 23 subjects were combined, there was a mean decrease of 10% in blood pressure (BP) 30 min after the loading dose (P < 0.001). Heart rate change was less significant. Clinicians identified four hypotensive episodes as temporally associated with the midazolam load, two each in Groups I (0.08 mg.kg-1) and III (placebo). One subject in Group I (the 23rd) became hypotensive within five min of receiving the loading dose, had a difficult clinical course and died four weeks postoperatively. We cannot conclude that the loading dose of midazolam had any systematic haemodynamic effect in our study population. Although the clinical course of the 23rd subject suggests a subset of more susceptible children (those who receive opioid analgesia with midazolam, are volume-restricted, and/or undergo more complex forms of surgical correction), many critical care patients are inherently physiologically unstable, and concluding clinically that blood pressure fluctuation is drug related may be erroneous.

Mycoplasma pneumoniae as a cofactor in severe respiratory infections

We report the clinical events associated with severe bacterial or viral infections in four patients whose illnesses followed or coincided with acute Mycoplasma pneumoniae respiratory infection. We propose that M. pneumoniae has the ability to act as a cofactor in severe respiratory disease by facilitating alterations in local respiratory immunity or structure and function.

Obstructive lung disease in children after allogeneic bone marrow transplantation: evaluation with high-resolution CT

OBJECTIVE

Obstructive lung disease is a major complication of bone marrow transplantation related to graft-versus-host disease. The purpose of this study was to determine the usefulness of high-resolution CT to evaluate obstructive lung disease occurring in children after bone marrow transplantation.

MATERIALS AND METHODS

Ten high-resolution CT scans of the lungs were obtained in seven children who developed chronic obstructive lung disease after bone marrow transplantation. All seven patients had chronic graft-versus-host disease. Spirometry, the gold standard test, confirmed airflow obstruction in each case, five prior to high-resolution CT. Two patients were too young to have spirometry until 10 and 15 months respectively after successful high-resolution CT. Selected images from these studies were randomized with similar images from five control subjects and reviewed blindly. All images from scans in patients with obstructive lung disease were analyzed retrospectively for parenchymal hypoattenuation, bronchial dilatation, bronchial wall thickening, and abnormal parenchymal opacity. Expiratory air-trapping was assessed on cine high-resolution CT done in four cases.

RESULTS

Three blinded observers each correctly identified all five controls among 15 high-resolution CT examinations. No scan from a patient with obstructive lung disease was considered normal. Areas of parenchymal hypoattenuation affected 35 of 35 lobes of the lung. Expiratory air-trapping was shown by cine high-resolution CT. Subsegmental or segmental bronchial dilatation was seen in 23 of 25 lobes in five patients. Bronchial wall thickening was not a prominent feature. Increasing abnormality was demonstrated in three patients on follow-up high-resolution CT. The high-resolution CT abnormalities were similar to those reported in patients with bronchiolitis obliterans.

CONCLUSION

High-resolution CT of the lungs can show extensive abnormality in children who develop chronic obstructive lung disease after bone marrow transplantation. High-resolution CT is a useful noninvasive technique in the evaluation of this disease.

Obstructive lung disease in children after allogeneic bone marrow transplantation

Obstructive lung disease (OLD) has been described as a significant complication after allogeneic bone marrow transplantation (BMT). The incidence of OLD in adults appears to be low (approximately 3%), but there is little data for children. We analyzed 89 consecutive pediatric allogeneic BMTs, > or = 1.5 years post-BMT, performed at British Columbia's Children's Hospital from 1980 to 1992 for evidence of OLD. Diagnosis of OLD was based on clinical findings (nonproductive cough, wheezing, and dyspnea with no evidence of infection), pulmonary function tests (FEV1 < 80% and FEF25-75% < 60% predicted), lung biopsy, and computed tomography scan. Sixty-seven of the 89 children evaluated survived > or = 90 days and were classified as at risk for OLD. Thirteen of 67 (19.4%), developed OLD, 3 of which were transient. The development of OLD was strongly associated with the following high-risk groups: chronic graft-versus-host disease (GVHD) (37.1% OLD), increased donor age, acute GVHD, and either mismatched related or matched unrelated donor transplants. No correlation was found with methotrexate prophylaxis for GVHD, total body irradiation, or cytomegalovirus reactivity in either donor or recipient and the development of OLD. Further analysis of only children with chronic GVHD showed that liver involvement by GVHD before the onset of OLD (57.9%) was the only other significant predictive factor. We observed an overall increased prevalence of OLD in children compared with that previously reported in adults. Further studies are required to confirm whether age is a risk factor for development of OLD after allogeneic BMT.

Oxygen consumption-oxygen delivery relationship in children

We examined the relationship between oxygen consumption (VO2) and oxygen delivery (DO2) over a range of metabolic demand in two groups of children. We studied 15 children after cardiac surgery (plasma lactate levels < 2.2 mmol/L, VO2 < 6 ml/min per kilogram, oxygen extraction ratio < 25%); 8 were given transfusions with erythrocytes, 10 to 15 ml/kg, and 7 received adrenaline infusions (0.05 to 0.3 micrograms/kg per minute). Blood transfusions significantly increased DO2 (20.5 +/- 6.4 to 26.2 +/- 7.1 ml/min per kilogram; p < 0.05) but did not alter VO2. Adrenaline increased DO2 (19.9 +/- 5.0 to 25.9 +/- 6.1 ml/min per kilogram; p < 0.05) and VO2 (4.3 +/- 0.8 to 5.5 +/- 1.2 ml/min per kilogram; p < 0.05), but the oxygen excretion ratio and the mixed venous oxygen saturation were unchanged. We also measured VO2 and Doppler-derived DO2 in 25 normal children during exercise. The relationship during exercise is given by the following equation: VO2 index (in milliliters per minute per kilogram) = 0.88 x DO2 index - 6.95. Adrenaline infusions, but not blood transfusions, increased VO2 and DO2 together. This effect may be due to increased demand, analogous to exercise, and probably does not represent improved perfusion. We also found significant measurement error in DO2 and spontaneous variation in VO2. We believe that the concept of supply-dependent VO2 is based on a number of methodologic and measurement errors. It should not be used to justify potentially dangerous therapies in sick children.

Comparison of three methods for measuring respiratory mechanics in ventilated children

Continuous measurements of airway pressure, gas flow, and tidal volume were made in 22 mechanically ventilated children, both during steady state conditions and following airway occlusion at end-inflation. For each child, three methods of analyzing the stored data were used to generate values of respiratory system compliance and resistance: 1) end-inspiratory hold technique (Bone: Respir Care 28:597, 1983; Rossi et al. Am Rev Respir Dis 131:672, 1985); 2) constant flow technique (Rossi et al. J Appl Physiol 58:1849, 1985; Suratt et al. J Appl Physiol 49:1116, 1980); and 3) multiple linear regression (Roy et al. Comput Biomed Res 7:21, 1974; Bhutani et al. Pediatr Pulmonol 4:150, 1988). In the absence of an accepted standard, we used the inspiratory hold technique as a reference. All methods gave comparable values for respiratory mechanics over a wide clinical range. However, multiple linear regression was the most convenient of the three: it can be automated and continuously displayed, there is no subjective input, values are taken through the respiratory cycle, and it is completely noninvasive. We also found that respiratory system resistance was largely a measure of endotracheal tube resistance and that respiratory compliance is a more sensitive monitor of lung function in intubated children.

Infective endocarditis in children with congenital heart disease: comparison of selected features in patients with surgical correction or palliation and those without

The diagnostic and prognostic features of 44 episodes of infective endocarditis in 42 children with congenital heart disease were reviewed. Endocarditis occurred in 18 patients who had not had surgical correction or palliation of the defect (non-operated group). There were 26 episodes in 24 patients who had been treated surgically (operated group) (16 open and eight closed cardiac operations). Endocarditis occurred soon after open heart surgery in eight patients and as a late complication in the other 16. It recurred in two patients (operated group). Invasive monitoring and low cardiac output were consistent features in those patients who had endocarditis soon after open heart surgery whereas dental treatment was a common feature in non-operated cases and after closed cardiac operations. Late cases of endocarditis after open heart surgery had various microbiological features that were not typical of infection after dental problems. Gram positive infections occurred in non-operated patients and in those who had had closed cardiac operations. The group that had open heart surgery had infections caused by Gram positive, Gram negative, and anaerobic bacteria and fungi. Fever, anaemia, leucocytosis, and positive blood cultures were the only consistent findings. Vegetations were seen in nine of 12 patients at cross sectional echocardiography. All 12 (four non-operated, one closed, and seven open cases) needed acute surgical treatment. The mortality from infective endocarditis was 17% for non-operated cases, 0% for those who had had closed heart surgery, and 50% for those who had had open heart surgery. Infective endocarditis after open heart surgery differs from that in the other subgroups in terms of microbiology, source of infection, and outcome and its early diagnosis depends on a thorough investigation of minimal symptoms and signs.