N 326 Problems of Oxygenation Asthma - Chronic inflammatory disorder of airways- Causes airway hyper-responsiveness leading to wheezing, breathlessness, chest tightness, and cough- Affects about 20 million Americans- Women and African Americans have a 30% or greater prevalence- About 40% of cases are related to an allergic response- May be seasonal or year round depending on exposure to allergenAsthma Triggers - Induced or exacerbated after exerciseo Pronounced with exposure to cold air - Breathing through a scarf or mask may ↓ likelihood of symptomso With exercise, a proper warm up and cool down may prevent or reduce the incidence of exercise induced asthma- Air Pollutants - Cigarette or wood smoke, Vehicle exhaust, Elevated ozone levels, Sulfur dioxide- Most common form of occupational lung disease (Exposure to diverse agents) - Arrive at work well, but experience a gradual decline- Major precipitating factor of an acute asthma attacko ↑ inflammation hyper-responsiveness of the tracheobronchial system- Allergic rhinitis and nasal polyps, Large polyps are removed, Sinus problems are usually related to inflammation of the mucous membranes- Asthma triad: nasal polyps, asthma, and sensitivity to aspirin and NSAIDs -Wheezing develops in about 2 hrs, Sensitivity to salicylates (Found in many foods, beverages, and flavorings)- Food allergies may cause asthma symptoms - Avoidance diets , Rare in adults- Reflux of acid could be aspirated into lungs causing bronchoconstriction- Psychological factors can worsen the disease processo Attacks can trigger panic and anxietyo Extent of affect is unknownAsthma - Inflammatory mediators cause early-phase response- Vascular congestion- Edema formation- Production of thick, tenacious mucous- Bronchial muscle spasm- Thickening of airway wallsLate-phase response- Occurs within 4-10 hours after initial attack- Only occurs in 30-50% of patients- Can be more severe than early-phase and last for 24 hours or more- If airway inflammation is not treated or does not resolve, it may lead to irreversible lung damageIndoor Air Pollution – animal & hair dander, pets, dust mites, food, chemicals, damp basements, mildew, tobacco, pollen, moldWhy asthma makes it hard to breathe? Air enters the respiratory system from the nose and mouth and travels through the bronchial tubes, in a non-asthmatic person, the muscles around the bronchial tubes are relaxed and the tissue is thin, allowing for easy airflow, in an asthmatic person, the muscles of the bronchial tubes tighten and thicken, and the air passages become inflamed and mucus-filled, making it difficult for air to move Asthma Clinical Manifestations – hyperinflation of the lungs - Unpredictable and variableo Recurrent episodes of wheezing, breathlessness, cough, and tight chesto May be abrupt or gradualo Lasts minutes to hours- Expiration may be prolonged o Inspiration-expiration ratio of 1:2 to 1:3 or 1:4o Bronchospasm, edema, and mucus in bronchioles narrow the airwayso Air takes longer to move out- Wheezing is unreliable to gauge severity o Severe attacks may have no audible wheezingo Usually begins upon exhalation- Cough variant asthmao Cough is only symptomo Bronchospasm is not severe enough to cause airflow obstruction- Difficulty with air movement can create a feeling of suffocationo Patient may feel increasingly anxious- An acute attack usually reveals signs of hypoxemiao Restlessness, ↑ anxiety, Inappropriate behavioro ↑ pulse and blood pressureo Pulsus paradoxus (drop in systolic BP during inspiratory cycle > 10 mm Hg)When you have asthma – mucus lines the bronchial tubes, inflamed airways, alveoli with trapped air Complications of Asthma- Status asthmaticus - Severe, life-threatening attack unresponsive to usual treatment (Patient at risk for respiratory failure)- Causes of status asthmaticus - Viral illnesses, Ingestion of aspirin or other NSAIDs, Environmentalpollutants or allergen exposure, Emotional stress, Abrupt discontinuation of drug therapy, Abuse of aerosol medication, Ingestion of β-adrenergic blockers- Clinical manifestations of status asthmaticus result fromo Increased airway resistance from edemao Mucous pluggingo Bronchospasmo Respiratory acidosiso As attack severity ↑, work of breathing ↑, patient tires, and it is harder to overcome the ↑ resistance to breathingo Ultimately the patient deteriorates to hypercapnia and hypoxemia- Complications of status asthmaticuso Pneumothoraxo Pneumomediastinumo Acute cor pulmonaleo Severe respiratory muscle fatigue leading to respiratory arresto Death is usually result of respiratory arrest or cardiac failureDiagnostics - Detailed history and physical exam, Pulmonary function tests, Peak flow monitoring, Chest x-ray, ABGs, Oximetry, Allergy testing, Blood levels of eosinophils, Sputum culture and sensitivityCollaborative Care- Education - Start at time of diagnosis, Integrate through care- Self-management - Tailored to needs of patient, Culturally sensitive- Desired therapeutic outcomeso Control or eliminate symptomso Attain normal lung functiono Restore normal activitieso Reduce or eliminate exacerbations and side effects of medications- Mild intermittent and mild persistent asthmao Avoid triggers of acute attackso Pre-medicate before exercising (Choice of drug therapy depends on symptom severity)- Acute asthma episodeo Respiratory distresso Treatment depends upon severity and response to therapy (Severity measured with flow rates, Can be severe enough to require intubation and mechanical ventilation)- O2 therapy should be started and monitored with pulse oximetry or ABGs in severe cases- Acute asthma episodeo Louder wheezing may occur in airways that are responding to therapyo With progression normal breath sounds return and wheezing subsideso Inhaled β-adrenergic agonists by metered dose inhaler (Corticosteroids indicated if response is insufficient)- Status asthmaticuso Most therapeutic measures are the same as for acute episode (↑ in frequency and dose of bronchodilators)o IV corticosteroids are administered every 4-6 hourso Continuous monitoring of patient is criticalo IV magnesium sulfate is given as a bronchodilatoro Supplemental O2 is given by mask or nasal cannula for 90% O2 saturation (Arterial catheter may be used to facilitate frequent ABG monitoring)o IV fluids are given due to insensible loss of fluidsDrug Therapy- Long-term