Isabel Lind, MD

Evidence summary

Bronchiolitis is the most common diagnosis among hospitalized infants aged <1 year in the US.¹ It is usually mild with a self-limited course. A 1997 study following 1113 healthy full-term infants through 20 consecutive winter seasons showed a 5% hospitalization rate of all infants with a positive respiratory syncytial virus (RSV) cult\ure (hospitalization rates with other pathogens were not reported), confirming the mild nature of most cases of bronchiolitis.² RSV accounts for 50% to 80% of bronchiolitis, along with other pathogens such as parainfluenza virus, influenza virus, and human metapneumovirus. A recent analysis of Centers for Disease Control and Prevention data from 1979 to 1997 showed that an average of 95 children died annually in the US from bronchiolitis, and 77% of these were aged <1 year (median age at death was 3 months).³

When discrete measures such as vital signs and scoring scales for respiratory distress are compared, infants who have mild disease courses are very similar to those who subsequently have a more severe illness. This, combined with the low incidence of serious illness, lowers the predictive value of any single clinical criteria for hospital admission (including oxygen saturation, respiratory rate, apparent respiratory distress, and day of illness) to the degree that no objective criteria are useful to make a decision for or against hospitalization.^4,5

In 2 good-quality retrospective case-control studies, which enrolled infants with milder disease discharged from emergency departments, no infants returned with illness severe enough to require admission to an intensive care unit (ICU).^5,6 No criteria were found that could predict subsequent severe course and need for admission.

One good-quality prospective study that enrolled 213 infants, younger than 13 months and presenting with bronchiolitis as outpatients found that physician impression of appearance was a better predictor of severe illness than numeric scoring systems such as the Yale Observation Scale or the Clinical Asthma Score.⁷ Pulse oximetry (<95%), prematurity (<34 weeks gestational age), respiratory rate >70/minute, atelectasis, “ill” or “toxic” appearance, and age <3 months were associated with more severe illness (defined as inability to remain alert and active or well hydrated throughout their illness). Oxygen saturation (SaO₂) <95% was the most objective predictor of severity (positive predictive value=87%; negative predictive value=73%). The study population was more ill than what is typical in outpatient settings (42% required admission and 11% required mechanical ventilation); therefore the positive predictive value would be lower in a milder, more typical outpatient population.

In a retrospective case-control study of 542 otherwise healthy full-term infants aged <1 year admitted for bronchiolitis with positive RSV tests, tachypnea (rate >80) and hypoxia (SaO₂<85%) were predictive of the need for pediatric ICU–level care (the specificity for predicting deterioration was 97%, but the sensitivity was only 30%).⁴ The authors concluded that the use of any specific variable for a single patient is limited because of its low sensitivity for detecting the risk of an adverse outcome.

Several studies have attempted to define admission criteria or decision-making tools for admission of these infants, but all used the clinical opinion of the attending pediatrician as their gold standard and many excluded infants discharged within 24 hours, thus limiting their applicability to an outpatient population.^4,7-10 Common criteria in these studies were an SaO₂ ≤93% or history of complicating illness such as congenital heart disease, prematurity, or lung disease, plus the clinical impression of the attending physician.

TABLE
Risk factors for deterioration in infants with bronchiolitis

Recommendations from others

The American Academy of Pediatrics does not have a guideline addressing this issue. The only guideline listed at the National Guidelines Clearinghouse was a 2005 Cincinnati Children’s Hospital Medical Center guideline for managing infants with bronchiolitis; it is grounded in assuring good patient oxygenation and hydration.¹¹ This guideline does not give specific criteria for admission but leaves this decision to the judgment of the physician. It also notes that the benefits of hospitalization center on the ability to closely monitor clinical status (including airway maintenance and hydration) and educating parents. The guideline recommends starting supplemental oxygen when SaO₂ is consistently less than 91% and weaning when higher than 94%.

Evidence summary

Bronchiolitis is the most common diagnosis among hospitalized infants aged <1 year in the US.¹ It is usually mild with a self-limited course. A 1997 study following 1113 healthy full-term infants through 20 consecutive winter seasons showed a 5% hospitalization rate of all infants with a positive respiratory syncytial virus (RSV) cult\ure (hospitalization rates with other pathogens were not reported), confirming the mild nature of most cases of bronchiolitis.² RSV accounts for 50% to 80% of bronchiolitis, along with other pathogens such as parainfluenza virus, influenza virus, and human metapneumovirus. A recent analysis of Centers for Disease Control and Prevention data from 1979 to 1997 showed that an average of 95 children died annually in the US from bronchiolitis, and 77% of these were aged <1 year (median age at death was 3 months).³

When discrete measures such as vital signs and scoring scales for respiratory distress are compared, infants who have mild disease courses are very similar to those who subsequently have a more severe illness. This, combined with the low incidence of serious illness, lowers the predictive value of any single clinical criteria for hospital admission (including oxygen saturation, respiratory rate, apparent respiratory distress, and day of illness) to the degree that no objective criteria are useful to make a decision for or against hospitalization.^4,5

In 2 good-quality retrospective case-control studies, which enrolled infants with milder disease discharged from emergency departments, no infants returned with illness severe enough to require admission to an intensive care unit (ICU).^5,6 No criteria were found that could predict subsequent severe course and need for admission.

One good-quality prospective study that enrolled 213 infants, younger than 13 months and presenting with bronchiolitis as outpatients found that physician impression of appearance was a better predictor of severe illness than numeric scoring systems such as the Yale Observation Scale or the Clinical Asthma Score.⁷ Pulse oximetry (<95%), prematurity (<34 weeks gestational age), respiratory rate >70/minute, atelectasis, “ill” or “toxic” appearance, and age <3 months were associated with more severe illness (defined as inability to remain alert and active or well hydrated throughout their illness). Oxygen saturation (SaO₂) <95% was the most objective predictor of severity (positive predictive value=87%; negative predictive value=73%). The study population was more ill than what is typical in outpatient settings (42% required admission and 11% required mechanical ventilation); therefore the positive predictive value would be lower in a milder, more typical outpatient population.

In a retrospective case-control study of 542 otherwise healthy full-term infants aged <1 year admitted for bronchiolitis with positive RSV tests, tachypnea (rate >80) and hypoxia (SaO₂<85%) were predictive of the need for pediatric ICU–level care (the specificity for predicting deterioration was 97%, but the sensitivity was only 30%).⁴ The authors concluded that the use of any specific variable for a single patient is limited because of its low sensitivity for detecting the risk of an adverse outcome.

Several studies have attempted to define admission criteria or decision-making tools for admission of these infants, but all used the clinical opinion of the attending pediatrician as their gold standard and many excluded infants discharged within 24 hours, thus limiting their applicability to an outpatient population.^4,7-10 Common criteria in these studies were an SaO₂ ≤93% or history of complicating illness such as congenital heart disease, prematurity, or lung disease, plus the clinical impression of the attending physician.

TABLE
Risk factors for deterioration in infants with bronchiolitis

Recommendations from others

The American Academy of Pediatrics does not have a guideline addressing this issue. The only guideline listed at the National Guidelines Clearinghouse was a 2005 Cincinnati Children’s Hospital Medical Center guideline for managing infants with bronchiolitis; it is grounded in assuring good patient oxygenation and hydration.¹¹ This guideline does not give specific criteria for admission but leaves this decision to the judgment of the physician. It also notes that the benefits of hospitalization center on the ability to closely monitor clinical status (including airway maintenance and hydration) and educating parents. The guideline recommends starting supplemental oxygen when SaO₂ is consistently less than 91% and weaning when higher than 94%.

Evidence summary

Bronchiolitis is the most common diagnosis among hospitalized infants aged <1 year in the US.¹ It is usually mild with a self-limited course. A 1997 study following 1113 healthy full-term infants through 20 consecutive winter seasons showed a 5% hospitalization rate of all infants with a positive respiratory syncytial virus (RSV) cult\ure (hospitalization rates with other pathogens were not reported), confirming the mild nature of most cases of bronchiolitis.² RSV accounts for 50% to 80% of bronchiolitis, along with other pathogens such as parainfluenza virus, influenza virus, and human metapneumovirus. A recent analysis of Centers for Disease Control and Prevention data from 1979 to 1997 showed that an average of 95 children died annually in the US from bronchiolitis, and 77% of these were aged <1 year (median age at death was 3 months).³

When discrete measures such as vital signs and scoring scales for respiratory distress are compared, infants who have mild disease courses are very similar to those who subsequently have a more severe illness. This, combined with the low incidence of serious illness, lowers the predictive value of any single clinical criteria for hospital admission (including oxygen saturation, respiratory rate, apparent respiratory distress, and day of illness) to the degree that no objective criteria are useful to make a decision for or against hospitalization.^4,5

In 2 good-quality retrospective case-control studies, which enrolled infants with milder disease discharged from emergency departments, no infants returned with illness severe enough to require admission to an intensive care unit (ICU).^5,6 No criteria were found that could predict subsequent severe course and need for admission.

One good-quality prospective study that enrolled 213 infants, younger than 13 months and presenting with bronchiolitis as outpatients found that physician impression of appearance was a better predictor of severe illness than numeric scoring systems such as the Yale Observation Scale or the Clinical Asthma Score.⁷ Pulse oximetry (<95%), prematurity (<34 weeks gestational age), respiratory rate >70/minute, atelectasis, “ill” or “toxic” appearance, and age <3 months were associated with more severe illness (defined as inability to remain alert and active or well hydrated throughout their illness). Oxygen saturation (SaO₂) <95% was the most objective predictor of severity (positive predictive value=87%; negative predictive value=73%). The study population was more ill than what is typical in outpatient settings (42% required admission and 11% required mechanical ventilation); therefore the positive predictive value would be lower in a milder, more typical outpatient population.

In a retrospective case-control study of 542 otherwise healthy full-term infants aged <1 year admitted for bronchiolitis with positive RSV tests, tachypnea (rate >80) and hypoxia (SaO₂<85%) were predictive of the need for pediatric ICU–level care (the specificity for predicting deterioration was 97%, but the sensitivity was only 30%).⁴ The authors concluded that the use of any specific variable for a single patient is limited because of its low sensitivity for detecting the risk of an adverse outcome.

Several studies have attempted to define admission criteria or decision-making tools for admission of these infants, but all used the clinical opinion of the attending pediatrician as their gold standard and many excluded infants discharged within 24 hours, thus limiting their applicability to an outpatient population.^4,7-10 Common criteria in these studies were an SaO₂ ≤93% or history of complicating illness such as congenital heart disease, prematurity, or lung disease, plus the clinical impression of the attending physician.

TABLE
Risk factors for deterioration in infants with bronchiolitis

Recommendations from others

The American Academy of Pediatrics does not have a guideline addressing this issue. The only guideline listed at the National Guidelines Clearinghouse was a 2005 Cincinnati Children’s Hospital Medical Center guideline for managing infants with bronchiolitis; it is grounded in assuring good patient oxygenation and hydration.¹¹ This guideline does not give specific criteria for admission but leaves this decision to the judgment of the physician. It also notes that the benefits of hospitalization center on the ability to closely monitor clinical status (including airway maintenance and hydration) and educating parents. The guideline recommends starting supplemental oxygen when SaO₂ is consistently less than 91% and weaning when higher than 94%.