Asthma is a chronic, reversible, obstructive airway disease, characterized by wheezing. It is caused by a spasm of the bronchial tubes, or the swelling of the bronchial mucosa, after exposure to various stimuli.
INTRODUCTION:
Asthma is a chronic, reversible, obstructive airway disease, characterized by wheezing. It is caused by a spasm of the bronchial tubes, or the swelling of the bronchial mucosa, after exposure to various stimuli.
Asthma is the most common chronic disease in childhood. Most children experience their first symptoms by 5 years of age.
ETIOLOGY:
Asthma commonly results from hyperresponsiveness of the trachea and bronchi to irritants. Allergy influences both the persistence and the severity of asthma, and atopy or the genetic predisposition for the development of an IgE-mediated response to common airborne allergens is the most predisposing factor for the development of asthma.
CLASSIFICATION:
1. Extrinsic Asthma – called Atopic/allergic asthma. An “allergen” or an “antigen” is a foreign particle which enters the body. Our immune system over-reacts to these often harmless items, forming “antibodies” which are normally used to attack viruses or bacteria. Mast cells release these antibodies as well as other chemicals to defend the body.
Common irritants:
• Cockroach particles
• Cat hair and saliva
• Dog hair and saliva
• House dust mites
• Mold or yeast spores
• Metabisulfite, used as a preservative in many beverages and some foods
• Pollen
2. Intrinsic asthma – called non-allergic asthma, is not allergy-related, in fact it is caused by anything except an allergy. It may be caused by inhalation of chemicals such as cigarette smoke or cleaning agents, taking aspirin, a chest infection, stress, laughter, exercise, cold air, food preservatives or a myriad of other factors.
• Smoke
• Exercise
• Gas, wood, coal, and kerosene heating units
• Natural gas, propane, or kerosene used as cooking fuel
• Fumes
• Smog
• Viral respiratory infections
• Wood smoke
• Weather changes
ANATOMY AND PHYSIOLOGY:
The upper respiratory tract consists of the nose, sinuses, pharynx, larynx, trachea, and epiglottis.
The lower respiratory tract consist of the bronchi, bronchioles and the lungs.
The major function of the respiratory system is to deliver oxygen to arterial blood and remove carbon dioxide from venous blood, a process known as gas exchange.
The normal gas exchange depends on three process:
• Ventilation – is movement of gases from the atmosphere into and out of the lungs. This is accomplished through the mechanical acts of inspiration and expiration.
• Diffusion – is a movement of inhaled gases in the alveoli and across the alveolar capillary membrane
• Perfusion – is movement of oxygenated blood from the lungs to the tissues.
Control of gas exchange – involves neural and chemical process
The neural system, composed of three parts located in the pons, medulla and spinal cord, coordinates respiratory rhythm and regulates the depth of respirations
The chemical processes perform several vital functions such as:
• regulating alveolar ventilation by maintaining normal blood gas tension
• guarding against hypercapnia (excessive CO2 in the blood) as well as hypoxia (reduced tissue oxygenation caused by decreased arterial oxygen [PaO2]. An increase in arterial CO2 (PaCO2) stimulates ventilation; conversely, a decrease in PaCO2 inhibits ventilation.
• helping to maintain respirations (through peripheral chemoreceptors) when hypoxia occurs.
The normal functions of respiration O2 and CO2 tension and chemoreceptors are similar in children and adults. however, children respond differently than adults to respiratory disturbances; major areas of difference include:
• Poor tolerance of nasal congestion, especially in infants who are obligatory nose breathers up to 4 months of age
• Increased susceptibility to ear infection due to shorter, broader, and more horizontally positioned eustachian tubes.
• Increased severity or respiratory symptoms due to smaller airway diameters
• A total body response to respiratory infection, with such symptoms as fever, vomiting and diarrhea.
SIGNS AND SYMPTOMS:
1. Non Productive to Productive Cough
2. Dyspnea
3. Wheezing on expiration
4. Cyanosis
5. Mild apprehension and restlessness
6. Tachycardia and palpitation
7. Diaphoresis
PATHOPHYSIOLOGY:
CLINICAL MANIFESTATIONS:
1. Increased respiratory rate
2. Wheezing (intensifies as attack progresses)
3. Cough (productive)
4. Use of accessory muscles
5. Distant breath sounds
6. Fatigue
7. Moist skin
8. Anxiety and apprehension
9. Dyspnea
Steps of Clinical and Diagnostic as per National Asthma Education and Prevention Program
Mild Intermittent Asthma
• Symptoms ? 2 times per week
• Brief exacerbations
• Nighttime symptoms ? 2 times a month
• Asymptomatic and normal PEF (peak expiratory flow) between exacerbations
• PEF or FEV, (forced expiratory volume in 1 second) ? 80% of predicted value
• PEF variability < 20%
Mild Persistent Asthma
• Symptoms > 2 times/week, but less than once a day
• Exacerbations may affect activity
• Nighttimes symptoms > 2 times a month
• PEF/FEV ? 80% of predicted value
• PEF variability 20%-30%
Moderate Persistent Asthma
• Daily Symptoms
• Daily use of inhaled short-acting ?2 - agonists
• Exacerbations affect activity
• Exacerbations ? 2 times a week
• Exacerbations may last days
• Nighttime symptoms > once a week
• PEF/FEV > 60%-<80% of predicted value
• PEF variability > 30%
Severe Persistent Asthma
• Continual symptoms
• Frequent exacerbations
• Frequent nighttime symptoms
• Limited physical activity
• PEF or FEV ? 60% of predicted value
• PEF variability > 30 %
LABORATORY AND DIAGNOSTIC FINDINGS:
Spirometry will detect:
a. Decreased for expiratory volume (FEV)
b. Decreased peak expiratory flow rate (PEFR)
c. Diminished forced vital capacity (FVC)
d. Diminished inspiratory capacity (IC)
NURSING MANAGEMENT:
1. Assess respiratory status by closely evaluating breathing patterns and monitoring vital signs
2. Administer prescribed medications, such as bronchodilators, anti-inflammatories, and antibiotics
3. Promote adequate oxygenation and a normal breathing pattern
4. Explain the possible use of hyposensitization therapy
5. Help the child cope with poor self-esteem by encouraging him to ventilate feelings and concerns. Listen actively as the child speaks,
focus on the child’s strengths, and help him to identify the positive and negative aspects of his situation.
6. Discuss the need for periodic PFTs to evaluate and guide therapy and to monitor the course of the illness.
7. Provide child and family teaching. Assist the child and family to name signs and symptoms of an acute attack and appropriate
treatment measures
8. Refer the family to appropriate community agencies for assistance.