Respiratory rate and severity of illness in babies under 6 months old

Video based non-contact monitoring of respiratory rate and chest indrawing in children with pneumonia

OBJECTIVE

Pneumonia is the single largest cause of death in children worldwide due to infectious diseases. According to WHO guidelines, fast breathing and chest indrawing are the key indicators of pneumonia in children requiring antibiotic treatments. The aim of this study was to develop a video-based novel method for simultaneous monitoring of respiratory rate and chest indrawing without upsetting babies.

APPROACH

Respiratory signals, corresponding to periodic movements of chest-abdominal walls during breathing, were extracted by analyzing RGB (red, green, blue) components in video frames captured by a smartphone camera. Respiratory rate was then obtained by applying fast fourier transform on the de-noised respiratory signal. Chest indrawing was detected by analysing relative phases of regional chest-abdominal wall mobility. The performance of the developed algorithm was evaluated on both healthy and pneumonia children.

MAIN RESULTS

The proposed method can measure respiratory rate with an overall mean absolute error of 1.8 bpm in the range 18-105 bpm. Phase difference between regional chest wall movements in the chest indrawing (pneumonia) cases was found to be 143±23.9 degrees, which was significantly higher than that in the healthy cases 52.3 ±32.6 degrees (p<0.001).

SIGNIFICANCE

Being non-intrusive and non-subjective, this computer-aided method can be useful in the monitoring for respiratory rate and chest indrawing for the diagnosis of pneumonia and its severity in children.

Feeding and Swallowing Problems in Infants with Spinal Muscular Atrophy Type 1: an Observational Study

BACKGROUND

Infantile hereditary proximal spinal muscular atrophy (SMA) type 1 is characterized by onset in the first 6 months of life and severe and progressive muscle weakness. Dysphagia is a common complication but has not been studied in detail.

OBJECTIVE

To study feeding and swallowing problems in infants with SMA type 1, and to explore the relation between these problems and functional motor scores.

METHODS

We prospectively included 16 infants with SMA type 1 between September 2016 and October 2018. Eleven infants received palliative care and five infants best supportive care in combination with nusinersen. We compiled and used an observation list with feeding related issues and observed feeding sessions during inpatient and outpatient visits. The Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP INTEND) was used as a measure of motor function.

RESULTS

All infants in the palliative care group (median onset of disease 14 days (range 1-56); median inclusion in the study 52 days (range 16-252) demonstrated symptoms of fatigue during feeding and unsafe swallowing. Symptoms were short nursing sessions (10-15 minutes), and not being able to finish the recommended feeding volumes (72%); increased frequency of feeding sessions (55%); coughing when drinking or eating (91%), and wet breathing during and after feeding (64%).Two out of five infants in the nusinersen group (median onset of disease 38 days (range 21-90); inclusion in the study at 63 days (range 3-218) were clinically pre-symptomatic at the start of treatment. The other three infants showed symptoms of fatigue and unsafe swallowing at inclusion in the study. These symptoms initially decreased after the start of the treatment, but (re)appeared in all five infants between the ages of 8 to 12 months, requiring the start tube of feeding. In the same period motor function scores significantly improved (median increase CHOP INTEND 16 points).

CONCLUSION

Impaired feeding and swallowing remain important complications in infants with SMA type 1 after the start of nusinersen. Improvement of motor function does not imply similar gains in bulbar function.

Non-contact physiological monitoring of preterm infants in the Neonatal Intensive Care Unit

The implementation of video-based non-contact technologies to monitor the vital signs of preterm infants in the hospital presents several challenges, such as the detection of the presence or the absence of a patient in the video frame, robustness to changes in lighting conditions, automated identification of suitable time periods and regions of interest from which vital signs can be estimated. We carried out a clinical study to evaluate the accuracy and the proportion of time that heart rate and respiratory rate can be estimated from preterm infants using only a video camera in a clinical environment, without interfering with regular patient care. A total of 426.6 h of video and reference vital signs were recorded for 90 sessions from 30 preterm infants in the Neonatal Intensive Care Unit (NICU) of the John Radcliffe Hospital in Oxford. Each preterm infant was recorded under regular ambient light during daytime for up to four consecutive days. We developed multi-task deep learning algorithms to automatically segment skin areas and to estimate vital signs only when the infant was present in the field of view of the video camera and no clinical interventions were undertaken. We propose signal quality assessment algorithms for both heart rate and respiratory rate to discriminate between clinically acceptable and noisy signals. The mean absolute error between the reference and camera-derived heart rates was 2.3 beats/min for over 76% of the time for which the reference and camera data were valid. The mean absolute error between the reference and camera-derived respiratory rate was 3.5 breaths/min for over 82% of the time. Accurate estimates of heart rate and respiratory rate could be derived for at least 90% of the time, if gaps of up to 30 seconds with no estimates were allowed.

Design of a Remote Real-Time Monitoring System for Multiple Physiological Parameters Based on Smartphone

Background

Utilization of the widely used wearable sensor and smartphone technology for remote monitoring represents a healthcare breakthrough. This study aims to design a remote real-time monitoring system for multiple physiological parameters (electrocardiogram, heart rate, respiratory rate, blood oxygen saturation, and temperature) based on smartphones, considering high performance, autoalarm generation, warning transmission, and security through more than one method.

Methods

Data on monitoring parameters were acquired by the integrated circuits of wearable sensors and collected by an Arduino Mega 250 R3. The collected data were transmitted via a Wi-Fi interface to a smartphone. A patient application was developed to analyze, process, and display the data in numerical and graphical forms. The abnormality threshold values of parameters were identified and analyzed to generate an autoalarm in the system and transmitted with data to a doctor application via a third-generation (3G) mobile network and Wi-Fi. The performance of the proposed system was verified and evaluated. The proposed system was designed to meet main (sensing, processing, displaying, real-time transmission, autoalarm generation, and threshold value identification) and auxiliary requirements (compatibility, comfort, low power consumption and cost, small size, and suitability for ambulatory applications).

Results

System performance is reliable, with a sufficient average accuracy measurement (99.26%). The system demonstrates an average time delay of 14 s in transmitting data to a doctor application via Wi-Fi compared with an average time of 68 s via a 3G mobile network. The proposed system achieves low power consumption against time (4 h 21 m 30 s) and the main and auxiliary requirements for remotely monitoring multiple parameters simultaneously with secure data.

Conclusions

The proposed system can offer economic benefits for remotely monitoring patients living alone or in rural areas, thereby improving medical services, if manufactured in large quantities.

Mechanistic Understanding of High Flow Nasal Cannula Therapy and Pressure Support with an In Vitro Infant Model

Despite the increased use of high flow nasal cannula therapy, little has been done to predict airway pressures for a full breath cycle. A 3-month-old infant in vitro model was developed, which included the entire upper airway and the first three bifurcations of the lungs. A breathing simulator was used to create a realistic breath pattern, and high flow was provided using a Vapotherm unit. Four cannulas of varying sizes were used to assess the effects of the inner diameter and nasal occlusion of the cannulas on airway pressures. At 8 L min^-1, end expiratory pressures of 0.821-1.306 cm H₂O and 0.828-1.133 cm H₂O were produced in the nasopharynx and trachea, respectively. Correlations were developed to predict full breath cycle airway pressures, based on the gas flow rate delivered, cannula dimensions, as well as the breathing flow rate, for the nasopharynx and trachea. Pearson correlation coefficients for the nasopharynx and trachea correlations were 0.991 and 0.992, respectively. The developed correlations could be used to determine the flow rate necessary for a cannula to produce pressures similar to CPAP settings. The proposed correlations accurately predict the regional airway pressure up to and including 7 cm H₂O of support for the entire breath cycle.

Respiratory Rate During the First 24 Hours of Life in Healthy Term Infants

BACKGROUND AND OBJECTIVE

Abnormal respiratory rate (RR) is a key symptom of disease in the newborn. The aim of this study was to establish the reference range for RR during the first 24 hours of life in healthy infants born at term.

METHODS

Infants were included at the hospital postnatal ward when time permitted. During sleep or a defined quiet state, RR was counted at 2, 4, 8, 16, and 24 hours by placing the bell of a stethoscope in front of the nostrils and mouth for 60 seconds. Data on maternal health, pregnancies, and births were obtained from medical records and the Medical Birth Registry of Norway.

RESULTS

The study included 953 infants. Median RRs were 46 breaths/minute at 2 hours, thereafter 42 to 44 breaths/minute. The 95th percentile was 65 breaths/minute at 2 hours, thereafter 58 to 60 breaths/minute. The fifth percentile was 30 to 32 breaths/minute. Within these limits, the intraindividual variation was wide. The overall mean RR was 5.2 (95% confidence interval [CI], 4.7 to 5.7, P < .001) breaths/minute higher while awake than during sleep, 3.1 (95% CI, 1.5 to 4.8, P < .001) breaths/minute higher after heavy meconium staining of the amniotic fluid, and 1.6 (95% CI, 0.8 to 2.4, P < .001) breaths/minute higher in boys than girls. RR did not differ for infants born after vaginal versus cesarean deliveries.

CONCLUSIONS

The RR percentiles established from this study allow for a scientifically based use of RR when assessing newborn infants born at term.

Oronasopharyngeal suction versus wiping of the mouth and nose at birth: a randomised equivalency trial

BACKGROUND

Wiping of the mouth and nose at birth is an alternative method to oronasopharyngeal suction in delivery-room management of neonates, but whether these methods have equivalent effectiveness is unclear.

METHODS

For this randomised equivalency trial, neonates delivered at 35 weeks' gestation or later at the University of Alabama at Birmingham Hospital, Birmingham, AL, USA, between October, 2010, and November, 2011, were eligible. Before birth, neonates were randomly assigned gentle wiping of the face, mouth (implemented by the paediatric or obstetric resident), and nose with a towel (wipe group) or suction with a bulb syringe of the mouth and nostrils (suction group). The primary outcome was the respiratory rate in the first 24 h after birth. We hypothesised that respiratory rates would differ by fewer than 4 breaths per min between groups. Analysis was by intention to treat. This study is registered with ClinicalTrials.gov, number NCT01197807.

FINDINGS

506 neonates born at a median of 39 weeks' gestation (IQR 38-40) were randomised. Three parents withdrew consent and 15 non-vigorous neonates with meconium-stained amniotic fluid were excluded. Among the 488 treated neonates, the mean respiratory rates in the first 24 h were 51 (SD 8) breaths per min in the wipe group and 50 (6) breaths per min in the suction group (difference of means 1 breath per min, 95% CI -2 to 0, p<0·001).

INTERPRETATION

Wiping the nose and mouth has equivalent efficacy to routine use of oronasopharyngeal suction in neonates born at or beyond 35 weeks' gestation.

FUNDING

None.

Derivation and validation of age and temperature specific reference values and centile charts to predict lower respiratory tract infection in children with fever: prospective observational study

OBJECTIVES

To develop reference values and centile charts for respiratory rate based on age and body temperature, and to determine how well these reference values can predict the presence of lower respiratory tract infections (LRTI) in children with fever.

DESIGN

Prospective observational study.

PARTICIPANTS

Febrile children aged at least 1 month to just under 16 years (derivation population, n = 1555; validation population, n = 671) selected from patients attending paediatric emergency departments or assessment units in hospitals.

SETTING

One hospital in the Netherlands in 2006 and 2008 (derivation population); one hospital in the Netherlands in 2003-05 and one hospital in the United Kingdom in 2005-06 (validation population).

INTERVENTION

We used the derivation population to produce respiratory rate centile charts, and calculated 50th, 75th, 90th, and 97th centiles of respiratory rate at a specific body temperature. Multivariable regression analysis explored associations between respiratory rate, age, and temperature; results were validated in the validation population by calculating diagnostic performance measures, z scores, and corresponding centiles of children with diagnoses of pneumonic LRTI (as confirmed by chest radiograph), non-pneumonic LRTI, and non-LRTI.

MAIN OUTCOME MEASURE

Age, respiratory rate (breaths/min) and body temperature (°C), presence of LRTI.

RESULTS

Respiratory rate increased overall by 2.2 breaths/min per 1°C rise (standard error 0.2) after accounting for age and temperature in the model. We observed no interactions between age, temperature, and respiratory rates. Age and temperature dependent cut-off values at the 97th centile were more useful for ruling in LRTI (specificity 0.94 (95% confidence interval 0.92 to 0.96), positive likelihood ratio 3.66 (2.34 to 5.73)) than existing respiratory rate thresholds such as Advanced Pediatrics Life Support values (0.53 (0.48 to 0.57), 1.59 (1.41 to 1.80)). However, centile cut-offs could not discriminate between pneumonic LRTI and non-pneumonic LRTI.

CONCLUSIONS

Age specific and temperature dependent centile charts describe new reference values for respiratory rate in children with fever. Cut-off values at the 97th centile were more useful in detecting the presence of LRTI than existing respiratory rate thresholds.

Normal ranges of heart rate and respiratory rate in children from birth to 18 years of age: a systematic review of observational studies

BACKGROUND

Although heart rate and respiratory rate in children are measured routinely in acute settings, current reference ranges are not based on evidence. We aimed to derive new centile charts for these vital signs and to compare these centiles with existing international ranges.

METHODS

We searched Medline, Embase, CINAHL, and reference lists for studies that reported heart rate or respiratory rate of healthy children between birth and 18 years of age. We used non-parametric kernel regression to create centile charts for heart rate and respiratory rate in relation to age. We compared existing reference ranges with those derived from our centile charts.

FINDINGS

We identified 69 studies with heart rate data for 143,346 children and respiratory rate data for 3881 children. Our centile charts show decline in respiratory rate from birth to early adolescence, with the steepest fall apparent in infants under 2 years of age; decreasing from a median of 44 breaths per min at birth to 26 breaths per min at 2 years. Heart rate shows a small peak at age 1 month. Median heart rate increases from 127 beats per min at birth to a maximum of 145 beats per min at about 1 month, before decreasing to 113 beats per min by 2 years of age. Comparison of our centile charts with existing published reference ranges for heart rate and respiratory rate show striking disagreement, with limits from published ranges frequently exceeding the 99th and 1st centiles, or crossing the median.

INTERPRETATION

Our evidence-based centile charts for children from birth to 18 years should help clinicians to update clinical and resuscitation guidelines.

FUNDING

National Institute for Health Research, Engineering and Physical Sciences Research Council.

Aerosol therapy in infants and toddlers: past, present and future

Infants and toddlers are a unique subpopulation with regard to aerosol therapy. There are various anatomical, physiological and emotional factors peculiar to this age group that present significant difficulties and challenges for aerosol delivery. Most studies on the factors determining lung deposition of therapeutic aerosols are based on data from adults or older children, which cannot simply be extrapolated directly to infants. The present review describes why infants/toddlers are very different with respect to two major issues - namely their anatomy/physiology and their behavior. We suggest possible solutions and future research directions aimed at improving clinical outcomes of aerosol therapy in this age group.

Organism-specific platelet response and factors affecting survival in thrombocytopenic very low birth weight babies with sepsis

OBJECTIVE

To study organism-specific platelet response and factors affecting survival in thrombocytopenic very low birth weight (VLBW) babies with sepsis.

STUDY DESIGN

Very low birth weight babies (birth weight <1500 g) admitted to a single level-three intensive care unit from January 2000 to December 2005 were prospectively evaluated for sepsis by rapid screen test, blood counts and blood culture. In thrombocytopenic babies, organism-specific platelet response and its effect on various platelet parameters were evaluated. In addition, morbidity, mortality and factors affecting survival were studied.

RESULT

Sepsis was diagnosed in 230 of 620 (37%) patients. Gram-positive sepsis occurred in 20% (46/230), Gram-negative in 71% (164/230) and fungal in 8.6% (20/230) of patients. Thrombocytopenia was observed in 67% (155/230) of babies. The frequency and duration of thrombocytopenia were more with Gram-negative and fungal infections. The incidence of persistent bacteremia, multiorgan failure and death was more in thrombocytopenic neonates (P<0.01). The incidence of multiorgan failure and death was directly related to the duration of thrombocytopenia. On multiple logistic regression analysis, poor prognostic factors include a high SNAP score at admission, a severe drop in platelet count at onset of sepsis, a low platelet nadir, a prolonged duration of thrombocytopenia, a need for platelet transfusion, less number of days off ventilation and a prolonged stay in the hospital.

CONCLUSION

In thrombocytopenic VLBW babies with sepsis, organism-specific platelet response is seen. In addition, persistent bacteremia, multiorgan failure and death are more in these babies, and survival decreases with the increased severity and duration of thrombocytopenia, with prolonged ventilation and increased need for platelet transfusions.

Breathing Frequency Changes at the Onset of Stepping in Human Infants

Breathing frequency increases at the onset of movement in a wide rage of mammals including adult humans. Moreover, the magnitude of increase in the rate of breathing appears related to the rate of the rhythmic movement. We determined whether human infants show the same type of response when supported to step on a treadmill. Twenty infants (ages 9.7 ± 1.2 mo) participated in trials consisting of sitting, stepping on the treadmill, followed by sitting again. Breathing frequency was recorded with a thermocouple, positioned under one naris and taped to a soother that the infant held in his/her mouth. A video camera, electrogoniometers, and force platforms under the treadmill belts recorded stepping movements. We found that the rate of breathing changed at the beginning of stepping. Most surprisingly, we found that when infants stepped at a frequency slower than their breathing frequency in sitting, the breathing frequency decreased. Average breathing frequency during stepping was positively correlated with stepping frequency. There was no evidence of entrainment between stepping and breathing. In conclusion, the rapid change in breathing frequency at the beginning of movement is functional in infants. The direction and magnitude of change in breathing is associated with the leg movements.

Chest radiography in children aged 2-59 months diagnosed with non-severe pneumonia as defined by World Health Organization: descriptive multicentre study in Pakistan

OBJECTIVES

To evaluate the chest radiographs of children diagnosed with non-severe pneumonia on the basis of the current World Health Organization guidelines (fast breathing alone) for radiological evidence of pneumonia.

DESIGN

Descriptive analysis.

SETTING

Outpatient departments of six hospitals in four cities in Pakistan.

PARTICIPANTS

2000 children with non-severe pneumonia were enrolled; 1932 children were selected for chest radiography.

INTERVENTIONS

Two consultant radiologists used standardised WHO definitions to evaluate chest radiographs; no clinical information was made available to them. If they disagreed, the radiographs were read by a third radiologist; the final classification was based on agreement between two of the three radiologists.

MAIN OUTCOME MEASURES

Presence or absence of pneumonia on radiographs.

RESULTS

Chest radiographs were reported normal in 1519 children (82%). Radiological evidence of pneumonia was reported in only 263 (14%) children, most of whom had interstitial pneumonitis. Lobar consolidation was present in only 26 children. The duration of illness did not correlate significantly with the presence of radiological changes (relative risk 1.17, 95% confidence interval 0.91 to 1.49).

CONCLUSION

Most children diagnosed with non-severe pneumonia on the basis of the current WHO definition had normal chest radiographs.

Clinical predictors of the severity of bronchiolitis

INTRODUCTION

Bronchiolitis is the most common serious, acute viral infection in infants. Besides the diagnostic and treatment challenges, the appropriate time and the need of hospitalization remain unanswered. We wonder whether clinical predictors such as age less than 6 months, respiratory frequency more than 45 breaths per minute and oxygen saturation less than 95% could be of any help in assessing the severity of the disease and the need for admission.

MATERIALS AND METHODS

A prospective study was held in the emergency department from November 2000 to January 2002, in which each patient with positive nasopharyngeal respiratory syncytial virus was included. Other inclusion criteria were full-term birth, clinical signs of respiratory diseases, age between 2 weeks up to 24 months and no underlying illnesses such as bronchopulmonary dysplasia and chronic heart or lung diseases. The sensitivity, specificity and relative risk (RR) were calculated by statistical analyses.

RESULTS

During the study period, 378 patients were included, 117 of whom were hospitalized (31%). Age less than 6 months (sensitivity 62%, specificity 72% and RR 2.68 ), respiratory frequency more than 45 breaths per minute (sensitivity 68%, specificity 82% and RR 4.57) and oxygen saturation less than 95% (sensitivity 68%, specificity 87% and RR 4.67) predicted the severity of the pulmonary disease and the need for admission. The cumulative analysis of the three parameters showed a specificity of 91% and a sensitivity of 86%, with a relative risk of 4.54 among those admitted into the hospital. Respiratory frequency more than 45 breaths per minute (sensitivity 76%, specificity 82% and RR 2.85) and oxygen saturation less than 95% (sensitivity 84%, specificity 86% and RR 2.65) were more significant than age less than 6 months (sensitivity 60%, specificity 70% and RR 3.70) in predicting the admission into the paediatric intensive care unit.

CONCLUSION

Oxygen saturation less than 95%, respiratory frequency more than 45 breaths per minute and age less than 6 months in respiratory-distressed infants are important parameters to predict the need for admission and emphasize the severity of bronchiolitis.

Age related reference ranges for respiration rate and heart rate from 4 to 16 years

BACKGROUND

Clinical vital signs in children (temperature, heart rate, respiration rate, and blood pressure) are an integral part of clinical assessment of degree of illness or normality. Despite this, only blood pressure and temperature have a reliable evidence base. The accepted ranges of heart and respiration rate vary widely.

METHODS

This study examined 1109 children aged 4-16 years in their own schools. Age, sex, height, weight, and resting respiration rate and heart rate were recorded. The data were used to produce age related reference ranges for everyday clinical use.

RESULTS

Reference intervals are presented for the range of heart rate and respiration rate of healthy resting children aged 4-16 years. The recorded values are at variance with standard quoted ranges in currently available texts.

What have we learned from observational studies on neonatal sepsis?

OBJECTIVE

To assess how observational studies on neonatal sepsis can help define the knowledge base required for neonatal randomized, clinical trials.

DESIGN

Methodologic review of past observational studies and critical reviews.

RESULTS

Observational studies on neonatal sepsis have suffered from important limitations: failure to employ multivariate analyses, considering infection in isolation (ignoring coexisting respiratory distress), failure to provide likelihood ratios for predictors and combinations of predictors, and ignoring the phenomenologic dimension of clinicians' experience.

CONCLUSION

Future observational studies must address three key issues. They should begin with a clear analytic and sampling plan that pays careful attention to the proper use and reporting of multivariate analyses. Second, they must explicitly address two subpopulations: critically ill newborns with negative cultures and asymptomatic newborns with positive cultures. Finally, they should be theory driven and provide empirical physiologic data that permit situating their results in the context of the evolving systemic inflammatory response syndrome and PIRO (predisposition, infection, host response, organ dysfunction) models.

Definitions of bloodstream infection in the newborn

OBJECTIVE

To develop definitions of bloodstream infections in the newborn that would enable clinicians to identify infection early, so patients can be enrolled in clinical trials. The definitions should be useful for surveillance and epidemiologic purposes.

METHOD

Search of EMBASE, MEDLINE, and Cochrane Library using age and English language limited key words sepsis, septicemia, and shock. Extensive study of textbook of neonatology and discussions with experts in the field.

RESULTS

The search identified >2,000 references. The most appropriate were selected and reviewed. Definitions of bloodstream infection were developed after consultation with an international faculty.

CONCLUSION

Current definitions of neonatal infection (and associated categories) used by neonatal clinicians and researchers have been either adapted/modified from definitions developed for adults or generated by individuals to suit their local needs or the needs of a particular study. It is clear that definitions generated for adults are not applicable to children or to newborn infants. In addition, developing and using unique definitions to suit individual or local needs make comparisons of outcome data and result of studies very difficult. This article proposes a set of definitions that are based as much as possible on current evidence. These definitions may be applicable widely for daily management of an infant with an infection and for research and epidemiologic studies.

The vexatious vital: neither clinical measurements by nurses nor an electronic monitor provides accurate measurements of respiratory rate in triage

STUDY OBJECTIVE

Of all the vital signs, only respiratory rate is still measured clinically in most US triage systems. Previous studies have demonstrated the inaccuracy, poor interobserver agreement, and low variability of routine measurements of respiratory rate. We assess the variability and accuracy of triage nurses' measurements of respiratory rate against a criterion standard. Also, we assess electronic measurement of respiratory rate against the same criterion standard.

METHODS

Consecutive patients presenting to an urban teaching emergency department (ED) were enrolled in this prospective study. Electronic measurement of respiratory rate was recorded throughout the triage encounter when nurses were recording measurements of respiratory rate. Electronic respiratory rate was measured using transthoracic impedance plethysmography. Immediately after each triage evaluation, criterion standard measurements of respiratory rate were made by research assistants using the World Health Organization recommendation of auscultation or observation for 60 seconds.

RESULTS

We enrolled 159 patients. Variability was low for triage nurses' measurements of respiratory rate (SD 3.3) and electronic measurement of respiratory rate (SD 4.1) compared with criterion standard measurements of respiratory rate (SD 4.8; P <.05). Triage nurses' measurements of respiratory rate and electronic measurement of respiratory rate showed low sensitivity in detecting bradypnea and tachypnea. In a Bland-Altman analysis, triage nurses' measurements of respiratory rate and electronic measurement of respiratory rate showed poor agreement with criterion standard measurements of respiratory rate. Subgroup analysis of patients presenting with cardiac and respiratory symptoms yielded similar results.

CONCLUSION

Neither triage nurses nor an electronic monitor provides accurate measurements of respiratory rate in the ED. Emergency physicians should search for new electronic modalities for measuring respiratory rate to bring respiratory rate into line with other vital signs. Emergency physicians should also consider new clinical strategies for measuring respiratory rate.

Aerosol therapy and the fighting toddler: is administration during sleep an alternative?

Insufficient cooperation during administration of aerosols by pressurized metered dose inhaler (pMDI)/spacers is a problem in nearly 50% of treated children younger than 2 years. For these children, administration during sleep might be more efficient. However, it is unknown how much aerosol reaches the lungs during sleep. The aim of this study was to determine in vitro the lung dose in young children from a pMDI/spacer during sleep and while being awake. Breathing patterns were recorded by a pneumotachograph in 18 children (age 11 +/- 5.1 months) during sleep and wakefulness. Next, breathing patterns were replayed by a computer-controlled breathing simulator to which an anatomically correct nose-throat model of a 9-month-old child was attached. One puff of budesonide (200 microg) was administered to the model via a metal spacer. Aerosol was trapped in a filter placed between model and breathing simulator. The amount of budesonide on the filter (5 lung dose) was analyzed by HPLC. For each of the 36 breathing patterns, lung dose was measured in triplicate. The sleep breathing patterns had significantly lower respiratory rate and peak inspiratory flows, and smaller variability in respiratory rate, tidal volume, and peak inspiratory flows. Lung dose (mean +/- SD) was 6.5 +/- 3.2 and 11.3 +/- 3.9 microg (p = 0.004) for the wake and sleep breathing pattern, respectively. This infant model-study shows that the lung dose of budesonide by pMDI/spacer is significantly higher during sleep compared to inhalation during wake breathing. Administration of aerosols during sleep might, therefore, be an efficient alternative for uncooperative toddlers.

Vital signs

BACKGROUND

Vital signs traditionally consist of blood pressure, temperature, pulse rate and respiratory rate, and are an important component of monitoring the patient's progress during hospitalisation. An initial search of the literature indicated that there was a vast volume of published information relating to this topic; however, there had been no previous attempt to systematically review this literature. This review was therefore initiated to identify, appraise and summarise the best available evidence relating to the measurement of vital signs in hospital patients.

OBJECTIVES

The objectives of this review were to present the best available information related to the monitoring of patient vital signs with regard to their purpose, limitations, optimal frequency of measurements, and what measures should constitute vital signs. The review also sought to identify additional issues of importance related to the individual parameters of temperature measurement, blood pressure assessment, pulse rate measurement and respiratory rate measurement.

REVIEW METHODS

This review considered all studies that related to the objectives and included neonatal, paediatric and/or adult hospital patients. The outcome measures of interest were those related to the accuracy of, required frequency of or the need for vital signs. The review also considered any study addressing some aspect of vital signs measurement to ensure all issues of importance were identified. The search sought to find both published and unpublished studies. Databases searched included CINAHL, Medline, Current Contents, Cochrane Library, Embase and Dissertation Abstracts. The references of all identified studies were examined for additional references. All studies were checked for methodological quality, and data was extracted using a data extraction tool.

RESULTS

Although a variety of measures may be useful additions to the traditional four vital sign parameters, only pulse oximetry and smoking status have been shown to change patient care and outcomes. There are suggestions that vital sign monitoring has become a routine procedure, but little useful information was identified in regard to the optimal frequency of vital sign measurement. It was noted that many of the important issues related to vital sign measurement have not been investigated through research.There is currently only limited research related to respiratory rate as a vital sign; however, its value as an indicator of serious illness has not been reliably established. There is only limited research relating to pulse rate measurements. Although routinely used for all hospital patients, the ability to detect serious physiological changes by assessment of pulse rate has not been rigorously evaluated. Many factors were identified that could potentially influence the accuracy of blood pressure measurement. Auscultation is accurate for the measurement of systolic blood pressure using phase I Korotkoff sound as the reference point, and for diastolic pressure if phase V Korotkoff sounds are used. Cuff size can influence accuracy, in that using a cuff that is too narrow will likely overestimate blood pressure and a cuff that is too wide will underestimate the pressure. Research suggests that blood pressure should be measured on the upper arm, while the arm is resting at approximate heart level. Studies have shown that healthcare workers often measure blood pressure in an incorrect and inaccurate way, and this is of some concern. However, a small number of studies suggest that education programs can be effective in improving blood pressure measurement techniques. The largest volume of research identified during this review related to the measurement of temperature. For accurate measurement of oral temperatures the thermometer should be positioned in either the left or right posterior sublingual pocket and remain in the mouth for 6-7 min. Although oxygen therapy and different types of breathing patterns will not influence accuracy of oral temperature measurements, hot or cold liquids will. For the measurement of tympanic temperatures, an ear tug should be used to help straighten the external auditory canal and so ensure measurement accuracy. The presence of impacted cerumen will likely result in inaccurate measurements. The only potential harm as a result of measuring vital signs was associated with glass mercury thermometers, in terms of rectal perforation, the risk of mercury poisoning was not clearly established.

CONCLUSIONS

Although there has been considerable research undertaken on many specific aspects of vital sign measurement, there is an urgent need for further primary research into the more general issues such as what parameters should be measured, the optimal frequency of measurements and the role of new technology in patient monitoring.

Counting respiratory rate in infants under 2 months: comparison between observation and auscultation

The World Health Organization's global programme for the control of acute respiratory infections relies on counting respiratory rate (RR) by observing abdominal and chest movements in order to diagnose pneumonia. However, few studies on the reliability of the observation method have been published. We counted RR simultaneously by observation and auscultation in 100 healthy infants at 1, 2, 4, 6 and 8 weeks of age for 15, 30 and 60 sec, and compared RRs obtained by the two methods. In all the age groups studied, the co-efficients of variation for the RRs recorded by observation or auscultation were similar. The mean RR by observation was higher by 1-3 breaths/min than mean RR by auscultation (p < 0.001). The 95% confidence interval (+/-2 SD) for the difference between RR by the two methods ranged from +5 to -8 breaths/min for RR counted for 1 full minute. Our data support the assumption that observation is as reliable as auscultation for counting RR.

Triage in the developing world--can it be done?

AIM

To assess guidelines for the emergency triage, assessment, and treatment (ETAT) of sick children presenting to hospitals in the developing world. This study pretested the guidelines in Malawi, assessing their performance when used by nurses compared to doctors trained in advanced paediatric life support (APLS).

METHODS

Triage was performed simultaneously by a nurse and assessing doctor on 2281 children presenting to the under 5s clinic. Each patient was allocated one of three priorities, according to the ETAT guidelines. Any variation between nurse and assessor was recorded on the assessment forms.

RESULTS

Nurses identified 92 children requiring emergency treatment and 661 with signs indicating a need for urgent medical assessment. One hundred and forty two (6.2%) had different priorities allocated by the APLS trained doctor, but these children did not tend to need subsequent admission. Eighty five per cent of admissions were prioritised to an emergency or urgent category.

CONCLUSION

Although there are no gold standards for comparison the ETAT guidelines appear to reliably select out the majority of patients requiring admission.

Evaluation of Children With Feeding and Swallowing Problems

Speech-language pathologists in schools are increasingly being presented with children who have feeding and swallowing problems. These speech-language pathologists are in strategic positions to identify the problems, carry out an evaluation of feeding and swallowing skills, and determine the needs for medical team referral. Evaluation of children with feeding and swallowing problems is best carried out by speech-language pathologists in the context of a school-based team with links to a medically based team. This article focuses on guidelines for obtaining a history, carrying out a physical examination, and observing a typical meal. Team members in school settings make important contributions to considerations for instrumental assessments that are needed when making management decisions for children with suspected pharyngeal phase deficits.

Tachypnoea is a good predictor of hypoxia in acutely ill infants under 2 months

OBJECTIVE

To evaluate the respiratory rate as an indicator of hypoxia in infants < 2 months of age.

SETTING

Pediatric emergency unit of an urban teaching hospital.

SUBJECTS

200 infants < 2 months, with symptom(s) of any acute illness.

METHODS

Respiratory rate (by observation method), and oxygen saturation (SaO(2)) by means of a pulse oximeter were recorded at admission. Infants were categorised by presence or absence of hypoxia (SaO(2) </= 90%).

RESULTS

The respiratory rate was >/= 50/min in 120 (60%), >/= 60/min in 101 (50. 5%), and >/= 70/min in 58 (29%) infants. Hypoxia (SaO(2) </= 90%) was seen in 77 (38.5%) infants. Respiratory rate and SaO(2) showed a significant negative correlation (r = -0.39). Respiratory rate >/= 60/min predicted hypoxia with 80% sensitivity and 68% specificity.

CONCLUSION

These results indicates that a respiratory rate > 60/min is a good predictor of hypoxia in infants under 2 months of age brought to the emergency service of an urban hospital for any symptom(s) of acute illness.

Respiratory rates of Indian infants under 2 months of age

There are few data from developing countries, including India, on the normal range of the respiratory rate (RR) recorded by observation. To determine the normal range of RR in infants up to 8 weeks of age and to define tachypnoea, we studied 100 healthy infants, 50 of normal birthweight and 50 of low birthweight) at 1, 2, 4, 6 and 8 weeks of age. The RR was recorded by observation and auscultation simultaneously for 60 seconds on each visit when the baby was either asleep or awake and content. The median RRs ranged between 42 and 43 breaths/min in infants of normal birthweight and 40 and 44 breaths/min. in low birthweight infants. Inter-age variability up to 8 weeks of age was very slight and statistically insignificant. Only 2-10% of the infants at any given age had a RR > or = 60/min. At all ages, RR by observation was higher than that by auscultation (p < 0.001). Neither birthweight nor gender significantly influenced the RR. When awake, infants had significantly higher RRs than when asleep. The RR extrapolated from a 15-second breath count was significantly lower (p < 0.05-0.01), whereas results from 30-second counts were similar to 60-second counts. Our data endorse the use of a RR > or = 60 breaths/min. counted for 1 minute as a cut-off to define tachypnoea in infants < 2 months of age.

Pulse oximetry as a fifth vital sign in emergency geriatric assessment

OBJECTIVE

To determine the utility of pulse oximetry as a routine fifth vital sign in emergency geriatric assessment.

METHODS

Prospective study using pulse oximetry to measure O2 saturation in geriatric patients presenting to ED triage. Saturation values were disclosed to clinicians only after they had completed medical evaluations and were ready to release or admit each patient. The authors measured changes in medical management and diagnoses initiated after the disclosure of pulse oximetry values. The study included 1,963 consecutive adults aged > or = 65 years presenting to triage at a university ED. Measurements included changes in select diagnostic tests: chest radiography, complete blood count (CBC), spirometry, arterial blood gases (ABGs), pulse oximetry, and ventilation-perfusion scans; treatments: antibiotics, beta-agonists, and supplemental O2; and hospital admission and final diagnoses that occurred after complete ED evaluation when physicians were informed of triage pulse oximetry values.

RESULTS

397 (20.2%) geriatric patients had triage pulse oximetry values <95%. Physicians ordered repeat oximetry for 51 patients, additional chest radiography for 23, CBC for 16, ABGs for 15, spirometry for 5, and ventilation-perfusion scans for none. Physicians ordered 49 new therapies for 44 patients, including antibiotics for 14, supplemental O2 for 29, and beta-agonists for 6. Nine patients initially scheduled for ED release were subsequently admitted to the hospital. Physicians changed or added diagnoses for 27 patients.

CONCLUSIONS

Using pulse oximetry as a routine fifth vital sign resulted in important changes in the diagnoses and treatments of a small proportion of emergency geriatric patients.

Pulse oximetry as a fifth pediatric vital sign

PURPOSE

To determine the utility of pulse oximetry as a routine fifth vital sign in acute pediatric assessment.

DESIGN

Prospective study using pulse oximetry to measure oxygen saturation in children presenting to emergency department triage. Saturation values were disclosed to clinicians only after they had completed medical evaluations and were ready to discharge or admit each child. We measured changes in medical treatment and diagnoses initiated after the disclosure of pulse oximetry values.

SETTING AND PARTICIPANTS

The study included 2127 consecutive children presenting to triage at a university emergency department.

MEASUREMENTS

Changes in select diagnostic tests: chest radiography, complete blood count, spirometry, arterial blood gases, pulse oximetry, and ventilation-perfusion scans; treatments: antibiotics, beta-agonists, supplemental oxygen; and hospital admission and final diagnoses that occurred after disclosure of triage pulse oximetry values.

RESULTS

Of 305 children having triage pulse oximetry values less than 95%, physicians ordered second oximetry for 49, additional chest radiography for 16, complete blood counts for 7, arterial blood gas measurements for 4, spirometry for 2, and ventilation-perfusion scans for 2. Physicians ordered 39 new therapies for 33 patients, including antibiotics for 15, supplemental oxygen for 11, and beta-agonists for 8. Five patients initially scheduled for hospital discharge were subsequently admitted. Physicians changed or added diagnoses in 25 patients.

CONCLUSIONS

Using pulse oximetry as a routine fifth vital sign resulted in important changes in the treatment of a small proportion of pediatric patients.

A comparison of pulse oximetry and respiratory rate in patient screening

OBJECTIVE

To examine how well respiratory rate correlates with arterial oxygen saturation status as measured by pulse oximetry, and determine whether respiratory rate measurements detect oxygen desaturation reliably.

METHODS

Respiratory rate (RR) and oxygen saturation (SaO2) were measured prospectively on 12,096 consecutive adult emergency department triage patients at a university medical center. Respiratory rate was measured by counting ausculated breath sounds for 1 min. Pulse oximetry was used to measure SaO2. Measurements were analysed by age (with one group for 18-19 year olds, groups for every 10 yr from age 20 to age 60, and groups for every 5 yr for subsequent ages). Pearson correlation coefficients were calculated for each age group as well as the weighted average coefficient. Cases having oxygen saturation below 90% were examined to determine how frequently they exhibited increased RR (increased RRs were defined as any rate in the upper five percentile by age.

RESULTS

Correlation coefficients ranged from 0.379 to -0.465 with a weighted mean of -0.160. Coefficients for ages 18 through 70 years (representing 10,740 patients) all had magnitude < 0.252. Overall, only 33% of subjects with oxygen saturation below 90% exhibited increased RR.

CONCLUSIONS

Respiratory rate measurements correlate poorly with oxygen saturation measurements and do not screen reliably for desaturation. Patients with low SaO2 do not usually exhibit increased RR. Similarly, increased RR is unlikely to reflect desaturation.

Effect of routine emergency department triage pulse oximetry screening on medical management

PURPOSE

To determine the utility of routine triage pulse oximetry screening in emergency department (ED) patients.

DESIGN

Prospective study using pulse oximetry to measure oxygen saturation of ED patients at triage. Saturation values were disclosed to physicians only after they completed medical evaluations and were ready to discharge or admit each patient. We measured changes in medical management initiated after disclosure of pulse oximetry values.

SETTING AND PARTICIPANTS

The study included 14,059 consecutive patients presenting to triage at a university ED.

MEASUREMENTS

Changes in select diagnostic tests: chest radiography, CBC count, spirometry, arterial blood gases, pulse oximetry, and ventilation-perfusion scans; treatments: antibiotics, beta-agonists, supplemental oxygen; and hospital admission and final diagnoses that occurred after disclosure of triage pulse oximetry values.

RESULTS

Of 1,175 patients having triage pulse oximetry values less than 95%, physicians ordered repeat pulse oximetry on 159 (13.5%), additional chest radiography on 5.4%, CBC count on 3.1%, arterial blood gases on 2.9%, spirometry on 0.9%, and ventilation-perfusion scans on 0.3%. Physicians ordered 178 new therapies on 134 patients (11.4%), including supplemental oxygen for 6.5%, antibiotics for 3.9%, and beta-agonists for 1.8%. Thirty-five patients (3.0%) initially scheduled for hospital discharge were subsequently admitted. Physicians changed or added diagnoses in 77 patients (6.6%).

CONCLUSIONS

Providing physicians with routine triage pulse oximetry measurements resulted in significant changes in medical treatment of these patients.

[Comparative study of nebulized sambutol against placebo in the acute phase of bronchiolitis in 33 infants aged 1 to 6 months]

BACKGROUND

The therapeutic role of bronchodilators in bronchiolitis remains controversial. The aim of this study is to evaluate the safety and the clinical response to nebulized salbutamol in infants with mild acute bronchiolitis.

PATIENTS AND METHODS

Thirty-three infants, aged 1 month to 5 months and 22 days (mean: 92.4 days) were included in the study. Patients received either nebulized salbutamol (0.15 mg/kg per dose: 16 infants) or a placebo (normal saline aerosol: 17 infants), delivered by an oxygen propellent, three times at intervals of 1 hour, as part of a double-blind randomized trial. Effect of treatment was evaluated by measuring respiratory and heart rate, clinical scores based on the degree of retraction and wheezing, and oxygen saturation. Clinical assessment was repeated 30 minutes after each nebulization. A nasopharyngeal swab was obtained for detection of respiratory syncytial virus (VRS) antigens by immunofluorescence assay in all patients.

RESULTS

Patients in the salbutamol group exhibited significantly greater improvement in respiratory rate (P = 0.01), accessory muscle score (P < 0.001) and wheezing score (P < 0.001). There was no significant difference in oxygen saturation between both groups. Infants treated with salbutamol exhibited a non-significant increase in heart rate after the three sprays; no other adverse effects were noted. VRS was identified in 78% of the children tested.

CONCLUSIONS

Salbutamol is safe and effective in relieving the respiratory distress of young infants with acute bronchiolitis. Our study confirms previous observations that infants younger than six months of age respond as well as older children when given three doses of nebulized salbutamol. Responders could not be differentiated from non responders by personal or family histories of atopy and VRS isolation. A longitudinal study could establish a correlation between response to bronchodilator therapy and later development of asthma.

Clinical predictors of acute radiological pneumonia and hypoxaemia at high altitude

Fast breathing has been recommended as a predictor of childhood pneumonia. Children living at high altitude, however, may breathe faster in response to the lower oxygen partial pressure, which may change the accuracy of prediction of a high respiratory rate. To assess the usefulness of clinical manifestations in the diagnosis of radiological pneumonia or hypoxaemia, or both, at high altitude (2640 m above sea level), 200 children aged 7 days to 36 months presenting to an urban emergency room with cough lasting less than seven days were studied. Parents were interviewed and the children evaluated using standard forms. The results of chest radiographs and pulse oximetry obtained after clinical examination were interpreted blind. Radiological pneumonia and haemoglobin oxygen saturation < 88% were used as 'gold standards'. One hundred and thirty (65%) and 125 (63%) children had radiological pneumonia and hypoxaemia respectively. Crepitations and decreased breath sounds were statistically associated with pneumonia, and rapid breathing as perceived by the child's mother, chest retractions, nasal flaring, and crepitations with hypoxaemia. The best single predictor of the presence of pneumonia is a high respiratory rate, although the results are not as good as those reported by other studies. A respiratory rate > or = 50/minute had good sensitivity (76%) and specificity (71%) for hypoxaemia in infants. Hypoxaemia had a good sensitivity and specificity for pneumonia mainly in infants (83% and 73%, respectively). Logistic regression analysis showed that decreased or increased respiratory sounds and crepitations were associated with pneumonia, and that hypoxaemia is the best predictor when auscultatory findings are excluded. These results suggest that some clinical predictors appear to be less accurate in Bogota than in places at lower altitude, and that pulse oximetry can be used for predicting pneumonia.

Reference ranges for respiratory rate measured by thermistry (12-84 months)

Previous studies of respiratory rate in children have had a number of methodological problems. The aim of this study was to construct age specific reference ranges for respiratory rate. Respiratory rate in children attending childcare centres, kindergartens, and schools was measured using a nasal thermocouple to obtain respiratory waveforms. Reference ranges were constructed using data from 293 awake children between 12 and 84 months, and from 123 sleeping children between 12 and 60 months. The mean respiratory rate declined with increasing age and was significantly lower, with lower variability, during sleep than wakefulness. Neither the awake nor sleeping reference ranges were significantly affected by sex, nor by the presence of past respiratory nor current respiratory symptoms.

Acute lower respiratory infection in Argentinian children: a 40 month clinical and epidemiological study

In a total of 1,003 children (805 inpatients and 198 outpatients) with acute lower respiratory infections (ALRI), clinical, social, and environmental data were analyzed. The major clinical entities were bronchiolitis, pneumonia, bronchitis, and laryngitis. The first two of these predominated in inpatients; pneumonia and bronchitis were more common in older children, while bronchiolitis was observed in infants. Respiratory rates of > 50/min. were more common in younger children and in cases with bronchiolitis and bronchitis. Retractions showed markedly less age-dependent variations and were present in all severe cases with different clinical diagnoses. Retractions alone or associated with cyanosis were the best indicators for severity of ALRI. Among outpatients, fever and wheezing were more common; inpatients were younger, more frequently malnourished, and from a lower socioeconomic level; family history of chronic bronchitis, crowding, and parental smoking also prevailed in this group. Family asthma and exposure to domestic aerosols was more common among outpatients. Prematurity rate (17 and 15%) of all ALRI cases was twice that of the general pediatric population and a significant difference existed between in- and outpatients under 6 months of age when perinatal respiratory pathologies predominated among inpatients. It is suggested to consider the need for assessing personal, family, and environmental risk factors in addition to clinical signs and symptoms when severe cases of ALRI are evaluated.

Recognition of illness in very young infants by inexperienced health workers

To determine whether inexperienced health workers can recognize severe infection in infants less than 3 months of age, a study was conducted of 200 infants with cough, fever or 'not feeling well'. The presence or absence of five symptoms: cough, difficulty in breathing, feeding problem, fever or history of convulsions, and ten signs: appearing ill, respiratory rate > or = 60/min, chest indrawing, grunting, cyanosis, wheeze, lethargy, 'too hot', 'too cold' or abdominal distension, were recorded by a health worker, who made a diagnosis of 'ill' or 'mildly ill'. Each infant was then reviewed by an experienced paediatrician who made a diagnosis of 'ill' (pneumonia, sepsis, meningitis or other severe illness) or 'mildly ill'. Using these diagnoses as the 'gold standard', the sensitivity, specificity, and positive predictive values of each parameter were calculated. In 89% of the 200 infants, the health worker made the correct diagnosis. Forty infants were admitted. In 36 instances (90%) the health worker made the correct decision. The most discriminating symptoms and signs were 'not feeding well', 'appears ill', chest indrawing and grunting. A respiratory rate > or = 60/min was 78% sensitive and 69% specific. Our study suggests that inexperienced health workers can recognize severe illness in infants under 3 months of age.

Respiratory rate: measurement of variability over time and accuracy at different counting periods

The respiratory rates/minute of 97 children were monitored every 10-15 minutes over one hour, by an observer and by pneumogram, at which times two 30 second and one 60 second counts were obtained. The children were under 5 years of age with lower respiratory tract infections (n = 20), upper respiratory tract infections (n = 34), or controls without acute respiratory infection (n = 43). The difference between respiratory rate count determined simultaneously by observation and pneumogram in relation to their mean count was analysed for the 60 second counting period, 30 plus 30 second period, and the 30 second period doubled. The mean difference for the 60 second period was 1.79, for the 30 plus 30 second period 1.42, and for the 30 second period doubled 1.72. The variability between respiratory rate counts determined by observation and pneumogram was significantly lower in counts obtained when the subject was sleeping and higher when agitated compared with obtaining a count when the subject was awake and calm or feeding. The variability was also significantly lower in subjects with lower respiratory tract infections compared with those with upper respiratory tract infections and control subjects without respiratory symptoms. In the same patient, over the one hour, 50% of the 60 second counts varied by up to 14 breaths/minute and 75% by up to 21 breaths/minute. The least variability was seen in children with a lower respiratory tract infection, who tended to maintain their rapid breathing in contrast to those with an upper respiratory tract infection and controls without respiratory symptoms. About 10% of initial 30 second counts, 12% of 60 second, and 16% of initial and repeat 30 second attempts to obtain accurate counts failed. Failures occurred more frequently in children <2 months of age and those agitated. The data from this study suggest that one minute's counting either at a stretch or in two blocks of 30 second intervals is better than counting the respiratory rate for 30 seconds, when the child is either awake and calm or when asleep.