Effects of body temperature on respiratory rate in young children

The role of body temperature on respiratory rate in children with acute respiratory infections

Background

The World Health Organization (WHO) recommends the use of tachypnea as a proxy to the diagnosis of pneumonia.

Objective

The purpose of this study was to examine the relationship between body temperature alterations and respiratory rate (RR) difference (RRD) in children with acute respiratory infections(ARI).

Methods

This cross-sectional study included 297 children with age 2–60 months who presented with cough and fever at the pediatric emergency and outpatient clinics in the Department of Pediatrics, Baskent University Hospital, from January 2016 through June 2018. Each parent completed a structured questionnaire to collect background data. Weight and height were taken. Body temperature, respiratory rate, presence of the chest indrawing, rales, wheezing and laryngeal stridor were also recorded. RRD was defined as the differences in RR at admission and after 3 days of treatment.

Results

Both respiratory rate and RRD were moderately correlated with body temperature (r=0.71, p<0.001 and r=0.65, p<0.001; respectively). For every 1°C increase in temperature, RRD increased by 5.7/minutes in overall, 7.2/minute in the patients under 12 months of age, 6.4/minute in the female. The relationship between body temperature and RRD wasn't statistically significant in patients with rhonchi, chest indrawing, and low oxygen saturation.

Conclusion

Respiratory rate should be evaluated according to the degree of body temperature in children with ARI. However, the interaction between body temperature and respiratory rate could not be observed in cases with rhonchi and severe pneumonia.

Temperature-Adjusted Respiratory Rate for the Prediction of Childhood Pneumonia

OBJECTIVES

As both fever and pneumonia can be associated with tachypnea, we investigated the relationship between body temperature and respiratory rate (RR) in young children and whether temperature-adjusted RR enhances the prediction of pneumonia.

METHODS

In this retrospective cross-sectional analysis of 91,429 children < 5 years of age presenting to an urban pediatric emergency department, the relationship between triage RR and temperature was analyzed using regression analysis. We assessed the predictive value of temperature-adjusted RR for the diagnosis of pneumonia; diagnostic performance was evaluated for continuous RR as well as World Health Organization (WHO) age-based RR thresholds.

RESULTS

The mean RR increased 2.6 breaths/minute for each 1°C increase in temperature. Interpatient variability was comparatively large; at any temperature, the interquartile range (75th percentile minus 25th percentile) varied from 4 to 16 breaths/minute. For predicting pneumonia, temperature- and age-adjusted RR was superior to age-adjusted RR: area under the curve (AUC) = 0.76 (95% confidence interval [CI], 0.75-0.78) versus AUC = 0.73 (95% CI, 0.72-0.75), respectively. Using WHO RR criteria, temperature-adjusted RR improved diagnostic discrimination, as the AUC increased from 0.58 (95% CI, 0.57-0.59) to 0.72 (95% CI, 0.70-0.73).

CONCLUSIONS

The effects of temperature on respiratory rate are modest, with a mean increase of 2.6 breaths/minute for each 1°C rise in temperature. Despite considerable interpatient variability in respiratory rates by temperature, temperature adjustment improves the diagnostic value of respiratory rate for pneumonia.

DOENÇAS RESPIRATÓRIAS AGUDAS EM CRIANÇAS BRASILEIRAS: OS CUIDADORES SÃO CAPAZES DE DETECTAR OS PRIMEIROS SINAIS DE ALERTA?

RESUMO Objetivo: Avaliar o nível de conhecimento do cuidador em relação aos sinais e sintomas respiratórios de Infecções Respiratórias Agudas (IRA) e a percepção dos mesmos em relação às crianças que necessitam de assistência médica. Métodos: Estudo prospectivo e transversal, no qual um questionário padronizado com itens relacionados à percepção da gravidade dos sinais e sintomas de IRA foi administrado a cuidadores de pacientes pediátricos admitidos no serviço de emergência de um hospital universitário no período de agosto de 2011 a maio de 2012. A análise estatística foi realizada com os testes do qui-quadrado e t-Student para determinar quais variáveis contribuíram para o reconhecimento pelos cuidadores da gravidade das doenças respiratórias agudas. Resultados: Foram entrevistados 499 cuidadores. As causas de IRA mais citadas foram Síndrome gripal (78,6%), Resfriado comum (73,9%), Faringites (64,1%) e Pneumonia (54,5%). Febre (34,1%) e Tosse (15,8%) foram as principais razões para a procura de atendimento. Os sinais de gravidade mais citados pelos cuidadores foram: febre (99,6%), dispneia (91,4%), sibilância (86,4%), adinamia (80,2%), tosse (79,8%) e taquipneia (78,6%). O histórico de doença respiratória anterior do paciente (p=0,002), a idade (p=0,010) e o estado civil do cuidador (p=0,014) foram as variáveis significativamente associadas com taquipneia, o sintoma mais grave de IRA. Conclusões: Embora cuidadores pediátricos possam perceber os principais sinais de IRA, eles não são capazes de reconhecer a gravidade destes, o que pode atrasar os cuidados médicos e impedir o tratamento precoce.

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.

Pneumonia in HIV-infected and HIV-uninfected children in developing countries

PURPOSE OF REVIEW

Pneumonia is a leading cause of illness and death in children younger than 5 years in developing countries, accounting for approximately 20% of childhood deaths. The HIV epidemic has sharply increased the incidence, severity, and mortality of childhood pneumonia in the developing world, particularly in sub-Saharan Africa. This article reviews recent findings on the epidemiology, clinical features, and management of HIV-infected and -uninfected children with pneumonia in developing countries.

RECENT FINDINGS

Bacterial infection remains a major cause of pneumonia mortality; in HIV-infected children, a broader spectrum of pathogens including gram-negative infections and Pneumocystis jiroveci occurs. Mycobacterium tuberculosis is an important cause of acute pneumonia among children from high tuberculosis prevalence areas. Use of case management guidelines substantially reduces neonatal, infant, and under-5 mortality and pneumonia-specific mortality in developing countries. New advances in therapy include the use of short-course antibiotics and high-dose amoxicillin twice daily for ambulatory treatment of HIV-negative children with pneumonia. New preventive interventions include the development of conjugate vaccines against Streptococcus pneumoniae and Haemophilus influenzae, but these are not widely affordable nor available in developing countries. Despite a lower efficacy in HIV-infected children, these vaccines still protect against disease in a significant proportion of children. Available preventive interventions including micronutrient supplementation with zinc and vitamin A, and immunization as contained in the WHO Expanded Program of Immunization can substantially reduce the burden of childhood pneumonia.

SUMMARY

Urgent measures to implement existing available, effective interventions for prevention and treatment of childhood pneumonia and achieve high coverage rates in developing countries are needed.

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.

Correcting respiratory rate for the presence of fever

This study defines what degree of respiratory rate (RR) elevation can be attributed to fever using a double blind randomized pre- and post-acetaminophen comparison of vital signs of febrile children presenting to an outpatient clinic. Inclusion criteria were aged between 6 weeks and 24 months, fever between 38.5 and 40.1 degrees C, no serious illness such as sepsis, and no recent receipt of antipyretics or antibiotics. RRs counted over 1 min and rectal temperatures were recorded by a trained observer before, and 1 and 1.5 hours (hr) after receipt of 10-15 mg/kg/dose of either acetaminophen (A) or placebo (P). Randomization produced groups A (n = 54), and P (n = 50) with similar mean age (12.3 vs 12.8 mo.), gender distribution (57 vs 54% female), baseline temperature (39.1 vs 39.1 degrees C), baseline RR (44 vs 45), and hours of fever prior to visit (42 vs 37 hr). The most common diagnoses were otitis media (49%), viral syndrome (18%), upper respiratory infection (16%) or gastroenteritis (7%). The mean temperature decrement of group A was 0.4 degrees C at 1 hr and 0.9 degrees C at 1.5 hr compared to slight increases in fever of 0.3 degrees C at 1 hr and 1.5 hr in group P. Significant decreases in RR occurred in group A compared to group P at 1 hr (7.0 vs 1.9, p = 0.009) and 1.5 hr (10.8 vs 4.0, p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Mothers' perceptions of severe pneumonia in their own children: a controlled study in Pakistan

In 1992, 320 mothers were interviewed in a Rawalpindi hospital to identify which of the signs and symptoms they saw in their own children were most consistently linked with a clinical diagnosis of pneumonia as opposed to common cold. A related goal was to determine whether mothers could correctly judge the actual presence or absence of two major pneumonia signs--fast breathing and chest indrawing. The mothers were predominantly poor and 43% were illiterate. The study sample was composed of four matched groups: (1) mothers of 80 children with pneumonia, most with severe disease, interviewed after the child was referred to the ward; (2) mothers of 80 such children interviewed in the outpatient clinic prior to any discussion of the pneumonia diagnosis; (3) mothers of 80 children with common cold; and (4) mothers of 80 'well' children. Results showed that when mothers were interviewed in the clinic, their perception that a child had fast breathing and/or chest indrawing was highly correlated with pneumonia (sensitivity 64%, specificity 90%). Mothers were even more likely to say that a child had these signs after the pneumonia diagnosis had been conveyed, suggesting that interaction with doctors influenced their views. Fast breathing was better recognized than chest indrawing, and accurate diagnosis of both signs was better among mothers having prior experience with childhood pneumonia. The data suggest that even in the absence of formal ARI education, a majority of Pakistani mothers attending hospitals in indigent areas can recognize these two signs in their own children. However, the seriousness of the signs and their connection with pneumonia should be stressed in education campaigns since a high percentage of children had chest indrawing (a late sign of severe disease) by the time they were brought to the hospital.

The effect of temperature reduction on respiratory rate in febrile illnesses

A raised respiratory rate is a useful sign in the diagnosis of pneumonia in children. It was observed that children with malaria and other febrile illnesses may also present with a raised respiratory rate. To determine the extent to which increased body temperature contributes to the raised respiratory rate observed in these children the effect of change in body temperature on respiratory rate was measured in 186 sick Gambian children with a raised respiratory rate, including those with pneumonia or malaria. A temperature dependent effect on respiratory rate of 3.7 breaths per minute per degree centigrade was demonstrated for the whole study cohort, with no significant difference between children with pneumonia or malaria. Twenty three per cent of children with pneumonia whose temperature fell had a final respiratory rate below that currently recommended by the World Health Organisation for the diagnosis of pneumonia. It is concluded that respiratory rate is to some extent dependent on body temperature in children with febrile illnesses such as pneumonia and malaria, but that this does not alone account for the raised respiratory rate seen in these children. The effect of reduction in body temperature on respiratory rate does not help to distinguish children with pneumonia from those with malaria. A history of recent use of an antipyretic or other measures to control fever is important when evaluating children for possible pneumonia.