Transcript RSV and Bronchiolitis

Bronchiolitis Caused by RSV:
A Clinical Review
VAPOTHERM
The Standard in High Flow Therapy
RSV and Bronchiolitis
Etiology, Epidemiology and Pathophysiology
Course Objectives
• Define bronchiolitis and RSV
• Understand the etiology, pathophysiology and
epidemiology of bronchiolitis caused by RSV
• Explain the clinical signs and symptoms of
bronchiolitis
• Understand how the characteristics of High
Flow Therapy (HFT) play a role in the
treatment of the symptoms of Bronchiolitis
• Review key research on the application of High
Flow Therapy in pediatric bronchiolitis patients
Bronchiolitis
• Acute inflammation of the
bronchioles
• characterized by swelling
and mucus buildup
• Typically caused by a viral
infection such as RSV
• Prevalent in young infants
• The leading cause of infant
hospitalization in the US
Chest x-ray of infant with RSV
(James Heilman, MD)
Overview of Bronchiolitis Caused
By RSV
• In children under 1 year, RSV is the most common cause
of bronchiolitis
• All children get RSV in first 3 years of life but in a small
% of them, it creates serious infection
• Most common cause of lower respiratory tract infection
in the first year of life
5
Bronchiolitis: Etiology
 Most cases result from a
viral pathogen
 RSV
 Parainfluenza virus
 Influenza virus
 Adenovirus
 RSV is the most common
 75% of children younger
than 2 hospitalized for
bronchiolitis.
Bronchiolitis in the ED1
 277 samples tested
 Positive for:
 RSV – 64%
 Rhinovirus - 16%
 Human metapneumovirus
(hMPV) - 9%
 Influenza A virus - 6%
1. Mansbach JM, McAdam AJ, Clark S, Hain PD, Flood RG, Acholonu U. Prospective multicenter study of the viral
etiology of bronchiolitis in the emergency department. Acad Emerg Med. Feb 2008;15(2):111-8.
Respiratory Syncytial Virus: RSV
 RSV is an enveloped RNA
virus
 Two strains (A & B ) are
recognized
 RSV is from common viral
family (Paramyxovirdae)
 RSV infection can be
confirmed using a simple lab
technique
 Direct Fluorescent Antibody
detection (DFA),
Transmission Electron
Micrograph of RSV
Transmission
 Highly contagious
 Spreads through:
• nasal secretions
• airborne droplets
• Fomites
RSV: Epidemiology
 Each year, nearly 125,000
children are hospitalized
due to an RSV infection
 RSV is seasonal
 93% of cases occurring
between November and
April
 Reinfection is common
From CDC
Bronchiolitis: Epidemiology
 More than 1/3 of children develop bronchiolitis in the
first two years of life
 3% of infants hospitalized in U.S.
 Low mortality with fewer than 400 deaths annually
 For infants under 6 months, 17 hospitalizations and 55
ED visits per 1000 children due to RSV
Bronchiolitis: Pathophysiology
The effects of bronchiolar injury include the following:
 Increased mucus secretion
 Bronchial obstruction and constriction
 Alveolar cell death, mucus debris, viral invasion
 Air trapping
 Atelectasis
 Labored breathing
Pathophysiology
in Infants
Infants are affected because:
•
Small airways
•
High closing volumes
•
Insufficient collateral
ventilation
Recovery:
•
Regeneration of bronchiolar
epithelium after 3-4 days
•
Cilia do not appear for as
long as 2 weeks.
Risk Factors
Risk factors for the development of bronchiolitis include
the following:
 Low birth weight
 Gestational age
 Lower socioeconomic group
 Crowded living conditions / daycare
 Parental smoking
Risk Factors
 Chronic lung disease, particularly bronchopulmonary
dysplasia
 Severe congenital or acquired neurologic disease
 CHD w/ pulmonary hypertension
 Congenital or acquired immune deficiency diseases
 Age less than 3 months
 Airway anomalies
Diagnosis and Treatment
Symptoms, Admissions Criteria and Treatment
Clinical Signs & Symptoms
Examination often reveals the following:

Tachypnea

Tachycardia

Fever (38-39°C)

Retractions / nasal flaring

Fine rales / Diffuse, fine wheezing
Hospital Admissions Criteria
Respiratory Status
 Respiratory distress, apnea, Tachypnea (>70 br/min) and/or clinical
evidence of increased work of breathing
 Patient requires oxygen supplementation
 Patient requires continuous clinical assessment of airway clearance and
maintenance using bulb suctioning
Nutritional Status
 Patient is dehydrated
 Patient is unable to maintain oral feedings at a level to prevent
dehydration
AHRQ national guidelines
Complications
• Acute respiratory distress syndrome (ARDS)
• Bronchiolitis obliterans
• Congestive heart failure
• Secondary infection
• Myocarditis
• Arrhythmias
• Chronic lung disease
Treatment and Management
 No definitive treatment
 At present, only oxygen appreciably improves the
condition of young children with bronchiolitis.7
 Medications have a limited role in the management
of RSV and bronchiolitis
Treatment & Management in
Hospitalized Patients
Mild Cases:
Moderate & Severe Cases:
 Cardio-respiratory
Monitoring
 CPAP
 Pulse Oximetry
 Oxygenation
Supplementation
 Maintenance of Hydration
 Humidification
 High flow nasal cannula
 Mechanical ventilation
Traditional Respiratory Support
Low Flow Oxygen
Non-Invasive Ventilation
Intubation
High Flow Therapy
Respiratory Support for Bronchiolitis
Accepted standard of care:
Humidity
Effects of High Flow Therapy via
Nasal Cannula on Bronchiolitis:
Setting flow rates to exceed the patients inspiratory demand:
Flush out of dead space removes
CO2
Creates internal reservoir of
desired FiO2
Patient breathes through own
airway instead of from external
source (ie: mask)
Decreases work of breathing
How High Flow Therapy Impacts
Bronchiolitis:
Why is heat and humidity important?
•Allows tolerability of higher flow
rates
•Improves mucocilliary process
•Decreases energy expenditure
Effects of HFT on Bronchiolitis:
Inflammed bronchiole as a result of
bronchiolitis
Ideally heated and humidified gas
improves and facilitates airway
conductance
Once open, much needed oxygen
can now reach the alveoli,
allowing for proper gas exchange
The Importance of Humidification:
Damaged cilia
Mucus collection
The Importance of Humidification:
Heated and humidified gas
restores cilia to its natural state,
allowing for secretion clearance
Clinical Impact
By instituting High Flow Therapy:
 Secretion Management
 Provide precise FiO2
 Reduce WOB with dead space flush
 Allows for better feeding tolerance
Improving Patient Tolerance &
Comfort
Not a mask therapy, resolves:
 Tolerance and adherence issues

Feeding issues
High flow cannula provides:
 simple interface
 Improves comfort / tolerance
 Less skin trauma
Decreased acuity of care
The Simplicity of the Nasal
Cannula
Research Review
High Flow Therapy and Bronchiolitis
Reduced intubation rates for infants after
introduction of high-flow nasal prong oxygen
delivery
Schibler A, Pham TM, Dunster KR, Foster K, Barlow
A, Gibbons K, Hough JL.
Intensive Care Med. 2011; 37(5):847-52.
A retrospective chart review to:
 Describe the change in PICU ventilatory practice after
adoption of HFT.
 Identify the patient subgroups requiring escalation of
therapy.
Schibler et al.
Intensive Care Med. 2011;37(5):847-52.
Overall
 298 infants <24 months of age received HFT.
 36 infants (12%) required escalation to MV
 No adverse events
Subgroup - viral bronchiolitis
 Of 167 infants, only 6 (4%) required escalation to MV.
 Rate of intubation reduced from 37% to 7%,
corresponding to an increase in the use of HFT.
Schibler et al.
Intensive Care Med. 2011;37(5):847-52.
Conclusions:
HFNP therapy has dramatically changed ventilatory
practice in infants <24 months of age
Appears to reduce the need for intubation in infants with
viral bronchiolitis.
High Flow Nasal Cannulae Therapy
in Infants with Bronchiolitis
McKiernan C, Chua LC, Visintainer PF, Allen H
Journal of Pediatrics. 2010; 156(4):634-638.
A retrospective chart review to of infants <24 months old
with bronchiolitis
Goal to determine if the introduction HFT was associated
with decreased rates of intubation
McKiernan et al.
Journal of Pediatrics. 2010; 156(4): 634-638.
Season after the introduction of HFT vs Season prior:
 Decrease in intubation from 23% to 9% (p < 0.05)
 HFNC therapy resulted in a greater decrease in
respiratory rate compared with other forms of
respiratory support
 infants with the greatest decrease in respiratory rate were
least likely to be intubated
 Median PICU length of stay decreased from 6 to 4 days
McKiernan et al.
Journal of Pediatrics. 2010; 156(4): 634-638.
HFT appears to decreases rates of intubation in infants
with bronchiolitis by decreasing the respiratory rate and
work of breathing
Provides a comfortable and well-tolerated means of
noninvasive ventilatory support.
Summary of Study Conclusions
 High flow therapy has been shown to reduce intubation
rates in infants with bronchiolitis
 High flow therapy is well tolerated
 High flow therapy administered with heliox further
improved respiratory scores
Thank You !
Questions?
Resources: Clinical Practice
Guidelines
 American Academy of Pediatrics,
Diagnosis and Management of
Bronchiolitis, 2006
 Cincinnati Children's Hospital Medical
Center (CCHMC). Evidence-based care
guideline for management of first time
episode bronchiolitis in infants less than 1
year of age. Cincinnati, OH
 Scottish Intercollegiate Guidelines
Network (SIGN). Bronchiolitis in children.
A national clinical guideline. Edinburgh
(Scotland): Scottish Intercollegiate
Guidelines Network (SIGN); 2006 Nov. 41 p