The role of pulse oximetry. Its use as an indicator of severe respiratory disease in Peruvian children living at sea level. Respiratory Group in Peru

Cost-effectiveness of pulse oximetry and integrated management of childhood illness for diagnosing severe pneumonia

Pneumonia is a major killer of children younger than five years old. In resource constrained health facilities, the capacity to diagnose severe pneumonia is low. Therefore, it is important to identify technologies that improve the diagnosis of severe pneumonia at the lowest incremental cost. The objective of this study was to conduct a health economic evaluation of standard integrated management of childhood illnesses (IMCI) guideline alone and combined use of standard IMCI guideline and pulse oximetry in diagnosing childhood pneumonia. This is a cluster-randomized controlled trial conducted in health centres in southern Ethiopia. Two methods of diagnosing pneumonia in children younger than five years old at 24 health centres are analysed. In the intervention arm, combined use of the pulse oximetry and standard IMCI guideline was used. In the control arm, the standard IMCI guideline alone was used. The primary outcome was cases of diagnosed severe pneumonia. Provider and patient costs were collected. A probabilistic decision tree was used in analysis of primary trial data to get incremental cost per case of diagnosed severe pneumonia. The proportion of children diagnosed with severe pneumonia was 148/928 (16.0%) in the intervention arm and 34/876 (4.0%) in the control arm. The average cost per diagnosed severe pneumonia case was USD 25.74 for combined use of pulse oximetry and standard IMCI guideline and USD 17.98 for standard IMCI guideline alone. The incremental cost of combined use of IMCI and pulse oximetry was USD 29 per extra diagnosed severe pneumonia case compared to standard IMCI guideline alone. Adding pulse oximetry to the diagnostic toolkit in the standard IMCI guideline could detect and treat one more child with severe pneumonia for an additional investment of USD 29. Better diagnostic tools for lower respiratory infections are important in resource-constrained settings, especially now during the COVID-19 pandemic.

The impact of pulse oximetry on diagnosis, management and outcomes of acute febrile illness in low-income and middle-income countries: a systematic review

BACKGROUND

Acute fever is a common presenting symptom in low/middle-income countries (LMICs) and is strongly associated with sepsis. Hypoxaemia predicts disease severity in such patients but is poorly detected by clinical examination. Therefore, including pulse oximetry in the assessment of acutely febrile patients may improve clinical outcomes in LMIC settings.

METHODS

We systematically reviewed studies of any design comparing one group where pulse oximetry was used and at least one group where it was not. The target population was patients of any age presenting with acute febrile illness or associated syndromes in LMICs. Studies were obtained from searching PubMed, EMBASE, CABI Global Health, Global Index Medicus, CINAHL, Cochrane CENTRAL, Web of Science and DARE. Further studies were identified through searches of non-governmental organisation websites, snowballing and input from a Technical Advisory Panel. Outcomes of interest were diagnosis, management and patient outcomes. Study quality was assessed using the Cochrane Risk of Bias 2 tool for Cluster Randomised Trials and Risk of Bias in Non-randomized Studies of Interventions tools, as appropriate.

RESULTS

Ten of 4898 studies were eligible for inclusion. Their small number and heterogeneity prevented formal meta-analysis. All studies were in children, eight only recruited patients with pneumonia, and nine were conducted in Africa or Australasia. Six were at serious risk of bias. There was moderately strong evidence for the utility of pulse oximetry in diagnosing pneumonia and identifying severe disease requiring hospital referral. Pulse oximetry used as part of a quality-assured facility-wide package of interventions may reduce pneumonia mortality, but studies assessing this endpoint were at serious risk of bias.

CONCLUSIONS

Very few studies addressed this important question. In LMICs, pulse oximetry may assist clinicians in diagnosing and managing paediatric pneumonia, but for the greatest impact on patient outcomes should be implemented as part of a health systems approach. The evidence for these conclusions is not widely generalisable and is of poor quality.

Defining hypoxaemia from pulse oximeter measurements of oxygen saturation in well children at low altitude in Bangladesh: an observational study

Background

WHO defines hypoxaemia, a low peripheral arterial oxyhaemoglobin saturation (SpO₂), as <90%. Although hypoxaemia is an important risk factor for mortality of children with respiratory infections, the optimal SpO₂ threshold for defining hypoxaemia is uncertain in low-income and middle-income countries (LMICs). We derived a SpO₂ threshold for hypoxaemia from well children in Bangladesh residing at low altitude.

Methods

We prospectively enrolled well, children aged 3–35 months participating in a pneumococcal vaccine evaluation in Sylhet district, Bangladesh between June and August 2017. Trained health workers conducting community surveillance measured the SpO₂ of children using a Masimo Rad-5 pulse oximeter with a wrap sensor. We used standard summary statistics to evaluate the SpO₂ distribution, including whether the distribution differed by age or sex. We considered the 2.5th, 5th and 10th percentiles of SpO₂ as possible lower thresholds for hypoxaemia.

Results

Our primary analytical sample included 1470 children (mean age 18.6±9.5 months). Median SpO₂ was 98% (IQR 96%–99%), and the 2.5th, 5th and 10th percentile SpO₂ was 91%, 92% and 94%. No child had a SpO₂ <90%. Children 3–11 months had a lower median SpO₂ (97%) than 12–23 months (98%) and 24–35 months (98%) (p=0.039). The SpO₂ distribution did not differ by sex (p=0.959).

Conclusion

A SpO₂ threshold for hypoxaemia derived from the 2.5th, 5th or 10th percentile of well children is higher than <90%. If a higher threshold than <90% is adopted into LMIC care algorithms then decision-making using SpO₂ must also consider the child’s clinical status to minimise misclassification of well children as hypoxaemic. Younger children in lower altitude LMICs may require a different threshold for hypoxaemia than older children. Evaluating the mortality risk of sick children using higher SpO₂ thresholds for hypoxaemia is a key next step.

Retrospective study on the usefulness of pulse oximetry for the identification of young children with severe illnesses and severe pneumonia in a rural outpatient clinic of Papua New Guinea

Objective

This secondary analysis of data of a randomized controlled trial (RCT) retrospectively investigated the performance of pulse oximetry in identifying children with severe illnesses, with and without respiratory signs/symptoms, in a cohort of children followed for morbid episodes in an intervention trial assessing the efficacy of Intermittent Preventive Treatment for malaria in infants (IPTi) in Papua New Guinea (PNG) from June 2006 to May 2010.

Setting

The IPTi study was conducted in a paediatric population visiting two health centres on the north coast of PNG in the Mugil area of the Sumkar District.

Participants

A total of 669 children visited the clinic and a total of 1921 illness episodes were recorded. Inclusion criteria were: age between 3 and 27 months, full clinical record (signs/symptoms) and pulse oximetry used systematically to assess sick children at all visits. Children were excluded if they visited the clinic in the previous 14 days.

Outcomes

The outcome measures were severe illness, severe pneumonia, pneumonia, defined by the Integrated Management of Childhood Illness (IMCI) definitions, and hospitalization.

Results

Out of 1921 illness episodes, 1663 fulfilled the inclusion criteria. A total of 139 severe illnesses were identified, of which 93 were severe pneumonia. The ROC curves of pulse oximetry (continuous variable) showed an AUC of 0.63, 0.68 and 0.65 for prediction of severe illness, severe pneumonia and hospitalization, respectively. Pulse oximetry allowed better discrimination between severe and non-severe illness, severe and non-severe pneumonia, admitted and non-admitted patients, in children ≤12-months of age relative to older patients. For the threshold of peripheral arterial oxygen saturation ≤ 94% measured by pulse oximetry (SpO₂), unadjusted odds ratios for severe illness, severe pneumonia and hospitalization were 6.1 (95% Confidence Interval (CI) 3.9–9.8), 8.5 (4.9–14.6) and 5.9 (3.4–10.3), respectively.

Conclusion

Pulse oximetry was helpful in identifying children with severe illness in outpatient facilities in PNG. A SpO₂ of 94% seems the most discriminative threshold. Considering its affordability and ease of use, pulse oximetry could be a valuable additional tool assisting the decision to admit for treatment.

Building a Prediction Model for Radiographically Confirmed Pneumonia in Peruvian Children: From Symptoms to Imaging

Background

Community-acquired pneumonia remains the leading cause of death in children worldwide, and current diagnostic guidelines in resource-poor settings are neither sensitive nor specific. We sought to determine the ability to correctly diagnose radiographically confirmed clinical pneumonia when diagnostics tools were added to clinical signs and symptoms in a cohort of children with acute respiratory illnesses in Peru.

Methods

Children < 5 years of age with an acute respiratory illness presenting to a tertiary hospital in Lima, Peru, were enrolled. The ability to predict radiographically confirmed clinical pneumonia was assessed using logistic regression under four additive scenarios: clinical signs and symptoms only, addition of lung auscultation, addition of oxyhemoglobin saturation (Spo₂), and addition of lung ultrasound.

Results

Of 832 children (mean age, 21.3 months; 59% boys), 453 (54.6%) had clinical pneumonia and 221 (26.6%) were radiographically confirmed. Children with radiographically confirmed clinical pneumonia had lower average Spo₂ than those without (95.9% vs 96.6%, respectively; P < .01). The ability to correctly identify radiographically confirmed clinical pneumonia using clinical signs and symptoms was limited (area under the curve [AUC] = 0.62; 95% CI, 0.58-0.67) with a sensitivity of 66% (95% CI, 59%-73%) and specificity of 53% (95% CI, 49%-57%). The addition of lung auscultation improved classification (AUC = 0.73; 95% CI, 0.69-0.77) with a sensitivity of 75% (95% CI, 69%-81%) and specificity of 53% (95% CI, 49%-57%) for the presence of crackles. In contrast, the addition of Spo₂ did not improve classification (AUC = 0.73; 95% CI, 0.69-0.77) with a sensitivity of 40% (95% CI, 33%-47%) and specificity of 72% (95% CI, 68%-75%) for an Spo₂ ≤ 92%. Adding consolidation on lung ultrasound was associated with the largest improvement in classification (AUC = 0.85; 95% CI, 0.82-0.89) with a sensitivity of 55% (95% CI, 48%-63%) and specificity of 95% (95% CI, 93%-97%).

Conclusions

The addition of lung ultrasound and auscultation to clinical signs and symptoms improved the ability to correctly classify radiographically confirmed clinical pneumonia. Implementation of auscultation- and ultrasound-based diagnostic tools can be considered to improve diagnostic yield of pneumonia in resource-poor settings.

Lung ultrasound as a diagnostic tool for radiographically-confirmed pneumonia in low resource settings

Background

Pneumonia is a leading cause of morbidity and mortality in children worldwide; however, its diagnosis can be challenging, especially in settings where skilled clinicians or standard imaging are unavailable. We sought to determine the diagnostic accuracy of lung ultrasound when compared to radiographically-confirmed clinical pediatric pneumonia.

Methods

Between January 2012 and September 2013, we consecutively enrolled children aged 2–59 months with primary respiratory complaints at the outpatient clinics, emergency department, and inpatient wards of the Instituto Nacional de Salud del Niño in Lima, Peru. All participants underwent clinical evaluation by a pediatrician and lung ultrasonography by one of three general practitioners. We also consecutively enrolled children without respiratory symptoms. Children with respiratory symptoms had a chest radiograph. We obtained ancillary laboratory testing in a subset.

Results

Final clinical diagnoses included 453 children with pneumonia, 133 with asthma, 103 with bronchiolitis, and 143 with upper respiratory infections. In total, CXR confirmed the diagnosis in 191 (42%) of 453 children with clinical pneumonia. A consolidation on lung ultrasound, which is our primary endpoint for pneumonia, had a sensitivity of 88.5%, specificity of 100%, and an area under-the-curve of 0.94 (95% CI 0.92–0.97) when compared to radiographically-confirmed clinical pneumonia. When any abnormality on lung ultrasound was compared to radiographically-confirmed clinical pneumonia the sensitivity increased to 92.2% and the specificity decreased to 95.2%, with an area under-the-curve of 0.94 (95% CI 0.91–0.96).

Conclusions

Lung ultrasound had high diagnostic accuracy for the diagnosis of radiographically-confirmed pneumonia. Added benefits of lung ultrasound include rapid testing and high inter-rater agreement. Lung ultrasound may serve as an alternative tool for the diagnosis of pediatric pneumonia.

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Lung ultrasound is emerging as a promising imaging alternative for the diagnosis of pneumonia in children.

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Existing studies in children are limited by small sample size, heterogeneity of populations, variable reference standards, and selection bias.

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We found that lung ultrasound can be implemented at a busy healthcare center with high diagnostic accuracy and high inter-rater agreement.

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Lung ultrasound was conducted without major disruptions in workflow, and it took <10 minutes to perform in most instances.

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This is the largest study demonstrating high diagnostic accuracy of lung ultrasound in children for the diagnosis of pneumonia.

Is Pulse Oximetry Useful for Screening Neonates for Critical Congenital Heart Disease at High Altitudes?

Now that pulse oximetry is used widely to screen for critical congenital heart disease, it is time to consider whether this screening method is applicable to those who live at high altitudes. Consideration of basic physical principles and reports from the literature indicate that not only is the 95 % cutoff point for arterial oxygen saturation incorrect at high altitudes, but the lower saturations are accompanied by greater variability and therefore there is the possibility of a greater percentage of false-positive screening tests at high altitudes. Because of ethnic differences in response to high altitudes, normative data will have to be collected separately in different countries and perhaps for different ethnic groups.

Evaluating the impact of pulse oximetry on childhood pneumonia mortality in resource-poor settings

It is estimated that pneumonia is responsible for 15% of childhood deaths worldwide. Recent research has shown that hypoxia and malnutrition are strong predictors of mortality in children hospitalized for pneumonia. It is estimated that 15% of children under 5 who are hospitalized for pneumonia have hypoxaemia and that around 1.5 million children with severe pneumonia require oxygen treatment each year. We developed a deterministic compartmental model that links the care pathway to disease progression to assess the impact of introducing pulse oximetry as a prognostic tool to distinguish severe from non-severe pneumonia in under-5 year olds across 15 countries with the highest burden worldwide. We estimate that, assuming access to supplemental oxygen, pulse oximetry has the potential to avert up to 148,000 deaths if implemented across the 15 countries. By contrast, integrated management of childhood illness alone has a relatively small impact on mortality owing to its low sensitivity. Pulse oximetry can significantly increase the incidence of correctly treated severe cases as well as reduce the incidence of incorrect treatment with antibiotics. We also found that the combination of pulse oximetry with integrated management of childhood illness is highly cost-effective, with median estimates ranging from US$2.97 to $52.92 per disability-adjusted life year averted in the 15 countries analysed. This combination of substantial burden reduction and favourable cost-effectiveness makes pulse oximetry a promising candidate for improving the prognosis for children with pneumonia in resource-poor settings.

Ultra-low-cost clinical pulse oximetry

An ultra-low-cost pulse oximeter is presented that interfaces a conventional clinical finger sensor with a mobile phone through the headset jack audio interface. All signal processing is performed using the audio subsystem of the phone. In a preliminary volunteer study in a hypoxia chamber, we compared the oxygen saturation obtained with the audio pulse oximeter against a commercially available (and FDA approved) reference pulse oximeter (Nonin Xpod). Good agreement was found between the outputs of the two devices.

Design and evaluation of a low-cost smartphone pulse oximeter

Infectious diseases such as pneumonia take the lives of millions of children in low- and middle-income countries every year. Many of these deaths could be prevented with the availability of robust and low-cost diagnostic tools using integrated sensor technology. Pulse oximetry in particular, offers a unique non-invasive and specific test for an increase in the severity of many infectious diseases such as pneumonia. If pulse oximetry could be delivered on widely available mobile phones, it could become a compelling solution to global health challenges. Many lives could be saved if this technology was disseminated effectively in the affected regions of the world to rescue patients from the fatal consequences of these infectious diseases. We describe the implementation of such an oximeter that interfaces a conventional clinical oximeter finger sensor with a smartphone through the headset jack audio interface, and present a simulator-based systematic verification system to be used for automated validation of the sensor interface on different smartphones and media players. An excellent agreement was found between the simulator and the audio oximeter for both oxygen saturation and heart rate over a wide range of optical transmission levels on 4th and 5th generations of the iPod TouchTM and iPhoneTM devices.

Reference values for oxygen saturation by pulse oximetry in healthy children at sea level in Chennai

There is little information on oxygen saturation (SaO2) values in children in developing countries.

AIM

To determine the reference values for oxygen saturation by pulse oximetry in healthy children living at sea level in Chennai and aged between 1 mth and 5 yrs.

DESIGN AND SETTING

A prospective study was conducted in Kanchi Kamakoti CHILDS Trust Hospital from February to May 2005.

METHODS

A total of 626 healthy children aged between 1 mth and 5 yrs were examined for heart rate, respiratory rate and SaO2.

RESULTS

The mean SaO2 levels for children in the age groups 1-3 mths, 3 mths to 1 yr, 1-3 years and 3-5 years were 98.5%, 98.8%, 98.9% and 99.1%, respectively. The overall mean and median SaO(2) values for the children in the different age groups were 99%. The mean -2 SD values of oxygen saturation in the age groups were 96.5%, 96.4%, 96.3% and 97.1%, respectively, with an overall mean of 96.6%.

CONCLUSION

The reference value for mean SaO2 in healthy children aged between 1 mth and 5 yrs and living at sea level in Chennai city was 98.5% or more, but the -2SD values had a mean of 96.6%.

Computerised lung sound analysis to improve the specificity of paediatric pneumonia diagnosis in resource-poor settings: protocol and methods for an observational study

INTRODUCTION

WHO case management algorithm for paediatric pneumonia relies solely on symptoms of shortness of breath or cough and tachypnoea for treatment and has poor diagnostic specificity, tends to increase antibiotic resistance. Alternatives, including oxygen saturation measurement, chest ultrasound and chest auscultation, exist but with potential disadvantages. Electronic auscultation has potential for improved detection of paediatric pneumonia but has yet to be standardised. The authors aim to investigate the use of electronic auscultation to improve the specificity of the current WHO algorithm in developing countries.

METHODS

This study is designed to test the hypothesis that pulmonary pathology can be differentiated from normal using computerised lung sound analysis (CLSA). The authors will record lung sounds from 600 children aged ≤5 years, 100 each with consolidative pneumonia, diffuse interstitial pneumonia, asthma, bronchiolitis, upper respiratory infections and normal lungs at a children's hospital in Lima, Peru. The authors will compare CLSA with the WHO algorithm and other detection approaches, including physical exam findings, chest ultrasound and microbiologic testing to construct an improved algorithm for pneumonia diagnosis.

DISCUSSION

This study will develop standardised methods for electronic auscultation and chest ultrasound and compare their utility for detection of pneumonia to standard approaches. Utilising signal processing techniques, the authors aim to characterise lung sounds and through machine learning, develop a classification system to distinguish pathologic sounds. Data will allow a better understanding of the benefits and limitations of novel diagnostic techniques in paediatric pneumonia.

Comparison of oxygen saturation levels by pulse oximetry in healthy children aged 1 month to 5 years residing at an altitude of 1500 metres and at sea level

OBJECTIVE

To compare oxygen saturation levels (SaO(2)) by pulse oximetry among healthy Indian children aged from 1 month to 5 years age residing at two different altitudes, Chennai and the Shervaroy hills.

DESIGN

Prospective observational study with a control group at sea level. SETTING 1: Chennai city which is at sea level (data published previously). SETTING 2: The Shervaroy hills (Yercaud, Salem district, Tamil Nadu) about 1500 metres above sea level (this study).

SUBJECTS

328 healthy children aged 1 month to 5 years living in the Shervaroy hills.

OUTCOME MEASURES

After assessment of anthropometry and heart and respiratory rates, oxygen saturation was recorded by pulse oximetry.

RESULTS

The mean SaO(2) values of children in the Shervaroy hills in the age groups 1 month to 3 years and 3-5 years were 97% and 98%, respectively. The mean -2 SD O(2) saturation values for the 1 month to 5 years age group was 93%. The overall mean and median values of oxygen saturation were 97% in the Shervaroy hills vs 99% for children in Chennai city (p<0.01). When compared with their counterparts in Chennai, the Shervaroy hills subjects had significantly lower mean weight and height and higher heart and respiratory rates (p<0.01).

CONCLUSION

The reference value for mean SaO(2) in healthy children aged 1 month to 5 years in the Shervaroy hills (1500 m) was 97%, with the (-2 SD) values having a mean of 93% which is significantly lower than those living in Chennai (sea level), 99% of whom had a -2 SD mean of 96.6%.

The prevalence of hypoxaemia among ill children in developing countries: a systematic review

Hypoxaemia is a common complication of childhood infections, particularly acute lower respiratory tract infections. In pneumonia-a disease that disproportionately impacts developing countries, and accounts for more than two million deaths of children worldwide-hypoxaemia is a recognised risk factor for death, and correlates with disease severity. Hypoxaemia also occurs in severe sepsis, meningitis, common neonatal problems, and other conditions that impair ventilation and gas exchange or increase oxygen demands. Despite this, hypoxaemia has been overlooked in worldwide strategies for pneumonia control and reducing child mortality. Hypoxaemia is also often overlooked in developing countries, mainly due to the low accuracy of clinical predictors and the limited availability of pulse oximetry for more accurate detection and oxygen for treatment. In this Review of published and unpublished studies of acute lower respiratory tract infection, the median prevalence of hypoxaemia in WHO-defined pneumonia requiring hospitalisation (severe and very severe classifications) was 13%, but prevalence varied widely. This corresponds to at least 1.5 to 2.7 million annual cases of hypoxaemic pneumonia presenting to health-care facilities. Many more people do not access health care. With mounting evidence of the impact that improved oxygen systems have on mortality due to acute respiratory infection in limited-resource health-care facilities, there is a need for increased awareness of the burden of hypoxaemia in childhood illness.

Clinical case review: a method to improve identification of true clinical and radiographic pneumonia in children meeting the World Health Organization definition for pneumonia

Background

The World Health Organization's (WHO) case definition for childhood pneumonia, composed of simple clinical signs of cough, difficult breathing and fast breathing, is widely used in resource poor settings to guide management of acute respiratory infections. The definition is also commonly used as an entry criteria or endpoint in different intervention and disease burden studies.

Methods

A group of paediatricians conducted a retrospective review of clinical and laboratory data including C-reactive protein concentration and chest radiograph findings among Filipino children hospitalised in the Bohol Regional Hospital who were enrolled in a pneumococcal vaccine efficacy study and had an episode of respiratory disease fulfilling the WHO case definition for clinical pneumonia. Our aim was to evaluate which disease entities the WHO definition actually captures and what is the probable aetiology of respiratory infections among these episodes diagnosed in this population.

Results

Among the 12,194 children enrolled to the vaccine study we recorded 1,195 disease episodes leading to hospitalisation which fulfilled the WHO criteria for pneumonia. In total, 34% of these episodes showed radiographic evidence of pneumonia and 11% were classified as definitive or probable bacterial pneumonia. Over 95% of episodes of WHO-defined severe pneumonia (with chest indrawing) had an acute lower respiratory infection as final diagnosis whereas 34% of those with non-severe clinical pneumonia had gastroenteritis or other non-respiratory infection as main cause of hospitalisation.

Conclusion

The WHO definition for severe pneumonia shows high specificity for acute lower respiratory infection and provides a tool to compare the total burden of lower respiratory infections in different settings.

Trial registration

ISRCTN62323832

The effects of swaddling on oxygen saturation and respiratory rate of healthy infants in Mongolia

BACKGROUND

Infant swaddling is common practice in some developing countries where infant respiratory morbidity is also prevalent. Little is known about the effect of swaddling on respiratory variables in healthy infants. Such information could have important implications for respiratory diseases.

AIMS

To compare respiratory rates (RR) and arterial oxygen saturations (SaO2) of healthy swaddled infants and non-swaddled infants during different conditions of sleep and arousal.

SETTING

Community based, nested case control study in Ulaanbaatar, Mongolia.

SUBJECTS AND METHODS

Habitually swaddled and non-swaddled infants aged 9-10 weeks taking part in a randomised controlled trial of swaddling. Respiratory rate and SaO2 were measured during quiet wakefulness, feeding, quiet and active sleep. Habitually swaddled infants were studied in swaddled and non-swaddled conditions. Habitually non-swaddled infants were studied only in the non-swaddled state.

RESULTS

SaO2 was higher during awake states compared with sleep states in all groups of infants. Habitually swaddled infants had lower mean SaO2 in the swaddled compared with non-swaddled condition (96.5% vs. 96.9%, p < 0.01) but these were not significantly different from the mean SaO2 of non-swaddled infants (96.9%, minimum p = 0.22). Habitually swaddled infants in the swaddled and non-swaddled states had similar respiratory rates, but these were, in both cases, significantly lower than in habitually non-swaddled infants.

CONCLUSION

Swaddling has little or no clinical effect on SaO2 or respiratory rates in healthy 9-10-week-old infants in Mongolia.

Brief hospitalization and pulse oximetry for predicting amoxicillin treatment failure in children with severe pneumonia

OBJECTIVE

In settings with limited assessment tools, we sought to determine whether early clinical signs and symptoms and blood oxygen saturation would predict amoxicillin treatment failure in children with severe pneumonia (as defined by the World Health Organization).

METHODS

Data were from a previously reported, multinational trial of orally administered amoxicillin versus injectable penicillin for the treatment of World Health Organization-defined severe pneumonia in children 3 to 59 months of age. We assessed all 857 participants assigned randomly to the experimental amoxicillin arm. Six multivariate logistic regression models were created and evaluated for their ability to predict failure after 48 hours of therapy. Regression models included vital signs, symptoms, and laboratory data collected at baseline and after 12 or 24 hours of observation. Oxygen saturation data were included in 3 models.

RESULTS

Clinical treatment failure occurred for 18% of children. Younger age, increased initial respiratory rate, and baseline hypoxia predicted treatment failure in all models. Data available after 24 hours improved the ability to predict failure compared with data available at baseline or 12 hours. The inclusion of oximetry data improved the predictive ability at baseline, 12 hours, and 24 hours. The ability to predict failure after 12 hours of observation with oximetry data was similar to the predictive ability after 24 hours without pulse oximetry data.

CONCLUSIONS

Assessment of clinical parameters at presentation and after 24 hours improved the ability to predict clinical failure of oral amoxicillin therapy, compared with assessment at presentation alone or at presentation and after only 12 hours, for children with World Health Organization-defined severe pneumonia.

Airway infectious disease emergencies

Upper and lower respiratory infections are encountered commonly in the emergency department. Visits resulting from occurrences of respiratory disease account for 10% of all pediatric emergency department visits and 20% of all pediatric hospital admissions. Causes of upper airway infections include croup, epiglottitis, retropharyngeal abscess, cellulitis, pharyngitis, and peritonsillar abscesses. Lower airway viral and bacterial infections cause illnesses such as pneumonia and bronchiolitis. Signs and symptoms of upper and lower airway infections overlap, but the differentiation is important for appropriate treatment of these conditions. This article reviews the varied clinical characteristics of upper and lower airway infections.

Blood gas analysis and chest x-ray findings in infants and preschool children with acute airway obstruction

BACKGROUND

The importance of SaO2 in the assessment of respiratory distress in bronchial asthma has been reported.

OBJECTIVES

To evaluate the correlation between blood gas analysis and chest X-ray lung opacities in young children presenting with acute respiratory symptoms.

METHODS

Eighty patients (43 males and 37 females aged 0.5-24 months; mean+/-SD 9.1+/-7.2 months), either with acute wheezing respiratory symptoms and/or with crackles were enrolled in our study. In all children, blood gas analysis and chest X-rays were performed within 12 h following admission to the emergency department.

RESULTS

In 55 children (68.75%) chest X-rays demonstrated lung opacities. Subjects with normal X-rays had paO2 and SaO2 higher than subjects with lung opacities (p<0.0001 and p=0.0001, respectively). Children with lung opacities almost always presented paO2<80 mm Hg. Sensitivity and specificity for the presence of lung opacities of paO2<80 mm Hg were 81 and 90%, respectively, while sensitivity and specificity of SaO2<95% were 92 and 40%, respectively. paO2<80 mm Hg in association with SaO2<95% had a positive predictive value for the diagnosis of pneumonia of 90.9%.

CONCLUSIONS

Our study suggests that blood gas analysis, particularly paO2, may help in predicting the presence of lung opacities in patients aged less than 2 years. However, chest X-rays may still be needed to define the actual extension of opacities as well as the possible concomitant presence of complications.

Pediatric pneumonia

Respiratory disease is common in pediatrics and diagnosing pneumonia may be clinically challenging. Changes in pneumococcal resistance and immunization practices continue to change the incidence and etiologies of pneumonia. Careful attention to epidemiologic, seasonal, and specific pediatric clinical factors and using adjunct radiographs and laboratory tests should guide the emergency physician in his or her management strategy, including selection of antibiotics and inpatient or outpatient disposition.

The use of pulse oximetry to exclude pneumonia in children

The objective of this study was to determine whether pulse oximetry alone or in conjunction with the clinical examination is predictive of pneumonia in children who present to the emergency department with respiratory complaints. A retrospective comparison of children with radiographic pneumonia with children with respiratory complaints and negative chest radiography was used. The study took place in an emergency department of a large academic, tertiary care hospital. All children less than 24 months of age who presented with a respiratory complaint and underwent chest radiography during a 1-year period were included. Charts of children with radiographic pneumonia were compared with charts of children without pneumonia, retrospectively. Data abstracted onto data collection forms included: pulse oximetry measurement, vital signs, general appearance, lung examination, and final radiology interpretation of chest radiographs. Pneumonia was defined as a chest radiograph showing any opacity consistent with pneumonia as read by a board-prepared or -certified radiologist. A total of 803 children qualified for the study. Radiograph interpretations were available for 762, and 10.5% were found to have radiographic pneumonia. The median pulse oximetry reading of children with radiographic pneumonia was 97% (interquartile range 95th-98th percentile) compared with 98% (interquartile range 96th-99th percentile) in the control group. Forty-five percent (35 of 78) of the children with radiographic pneumonia showed oxygen saturations of 98% or higher with greater than 10% (8 of 78) displaying oxygen saturations of 100%. By using logistic regression, pulse oximetry was not found to be a statistically significant predictive variable for radiographic pneumonia. Pulse oximetry could not be used to rule out the presence of radiographic pneumonia in children less than 2 years of age who presented with respiratory complaints.

Passive smoking, as measured by hair nicotine, and severity of acute lower respiratory illnesses among children

The aim of this study was to describe the association between passive smoking and the severity of acute lower respiratory illnesses (ALRI) among 351 children aged 3–27 months admitted to hospital. A total of 297 children provided hair samples, which were analysed for hair nicotine levels as an indicator of passive smoking. A severity of illness grading system was developed by using clinical and management criteria used by the medical staff at hospital. The OR for children with more severe illness being exposed to higher nicotine levels was 1.2, 95% CI: 0.57–2.58 when using dichotomised respiratory severity levels and upper versus lower nicotine quartile levels. In an ordinal logistic regression model, the OR of more severe illness being associated with higher nicotine levels was 1.07 (95% CI: 0.92–1.25). When analysis was limited to the more severe cases, the OR of the least severe category compared to the most severe category, in relation to nicotine levels in hair, was 1.79 (95% CI: 0.5–6.30). The ordinal logistic regression of this group of severely-ill children (OR 1.1 (95% CI: 0.94–1.29) was not substantially different from the overall study subjects.

In general, children with more severe illness tended to have higher levels of nicotine in their hair, although the results were within the limit of chance. Possible explanations of our results include environmental tobacco smoke (ETS) being an initiator of ALRI rather than a risk to severity, exposure levels of ETS were too low to demonstrate an effect on severity, or the power of this study was not high enough to detect an association.

Touchdown enzyme time release-PCR for detection and identification of Chlamydia trachomatis, C. pneumoniae, and C. psittaci using the 16S and 16S-23S spacer rRNA genes

Three touchdown enzyme time release (TETR)-PCR assays were used to amplify different DNA sequences in the variable regions of the 16S and 16S-23S spacer rRNA genes specific for Chlamydia trachomatis, Chlamydia pneumoniae, and Chlamydia psittaci as improved tests for sensitive diagnosis and rapid species differentiation. The TETR-PCR protocol used 60 cycles of amplification, which provided improved analytical sensitivity (0.004 to 0.063 inclusion-forming unit of Chlamydia species per PCR). The sensitivity of TETR-PCR with primer set CTR 70-CTR 71 was 96.7%, and the specificity was 99.6%, compared to those of the AMPLICOR PCR for the detection of C. trachomatis in vaginal swab samples. TETR-PCR for C. pneumoniae with primer set CPN 90-CPN 91 was 90% sensitive and 93.3% specific compared with a nested PCR with primer set CP1/2-CPC/D for clinical respiratory samples. TETR-PCR for C. psittaci with primer set CPS 100-CPS 101 showed substantial agreement with cell culturing (kappa, 0.78) for animal tissue samples. Primer sets were then combined into a single multiplex TETR-PCR test. The respective 315-, 195-, and 111-bp DNA target products were precisely amplified when DNA from each of the respective Chlamydia species or combinations of them was used. Multiplex chlamydia TETR-PCR correctly identified one strain of each of the 15 serovars of C. trachomatis, 22 isolates of C. pneumoniae, and 20 isolates of C. psittaci. The primer sets were specific for each species. No target products were amplified when DNA from C. pecorum or a variety of other microorganisms was tested for specificity. TETR-PCR with primers selected for specific sequences in the 16S and 16S-23S spacer rRNA genes is a valuable test that could be used either with individual primers or in a multiplex assay for the identification and differentiation of Chlamydia species from culture isolates or for the detection of chlamydiae in clinical samples.

Relation between pulse oximetry and clinical score in children with acute wheezing less than 24 months of age

The aim of this study was to determine the relation between transcutaneous hemoglobin oxygen saturation, measured by pulse oximetry (SpO2), and clinical score values in 138 infants (mean+/-SD, 6.6+/-5.5 months of age) with acute wheezing episodes presenting in a primary care outpatient setting. A single investigator evaluated the severity of the acute wheezing episodes by assigning a clinical score and was unaware of the SpO2 values. Another investigator measured SpO2 values on all subjects. The mean (+/-SD) SpO2 value was 98.2+/-1.1% for children with clinical scores of 2-5 (n = 32); 95.4+/-1.5% for those with scores of 6-7 (n = 82), and 92.9+/-2% for children with scores of 8-10 (n = 24), (P < 0.001 by Bonferroni's multiple comparison, when all two-way comparisons were done for each pair of results). The clinical score showed a good correlation with SpO2 (r = -0.76; 95% CI, -0.83 to -0.68). We conclude that if pulse oximetry is not available, it is advisable to include oxygen in the therapy of wheezy infants with clinical scores values >8.

Reference values for pulse oximetry at high altitude

OBJECTIVE

To determine reference values for oxygen saturation (Sao2) in healthy children younger than 5 years living at high altitude.

DESIGN

One hundred and sixty eight children were examined for Sao2 at 4018 m during well child visits. Physiological state was also noted during the examination.

RESULTS

The mean Sao2 was 87.3% (95% confidence intervals (CI) 86.7%, 87.9%) with a median value of 87.7%. A significant difference was observed in Sao2 between children younger than 1 year compared with older children, although the difference was no longer demonstrable when sleeping children were excluded.

CONCLUSIONS

This study has provided a reference range of Sao2 values for healthy children under 5 years old so that pulse oximetry may be used as an adjunct in diagnosing acute respiratory infections. Younger children were also shown to have a lower mean Sao2 than older children living at high altitude, which suggests physiological adaptation to high altitude over time. In addition, sleep had a lowering effect on Sao2, although the clinical importance of this remains undetermined.