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Status asthmaticus is life threatening asthma; it is also known as Acute Severe Asthma even though others tend to differentiate status asthmaticus from acute severe asthma. It is the most serious form of asthmatic attack that requires immediate diagnosis and urgent attention because the patient is unable to breathe completely and there are no breath sounds when a stethoscope is used to listen to the chest (silent chest asthma).
Status asthmaticus is a chronic inflammatory disease caused by triggers or agents that lead to airway over responsiveness to these agents. When the airway (most especially the bronchi) become inflamed, they limit airflow through them; in status asthmaticus, the limitation is greatly reduced to an extent that they individual cannot breathe. This condition does not respond to standard treatment for acute asthmatic attack and hence requires aggressive treatment and hospitalization may be necessary.
When you notice that there is rapid increase in the daily use of your bronchodilators to control acute asthma symptoms, this is a danger sign of an impending status asthmaticus.
Status Asthmaticus Definition
Status Asthmaticus is defined as asthma that is severe at its onset or progresses rapidly despite standard asthma therapy and without successful management it may progress to ventilatory failure and death.
Status Asthmaticus Causes
The main cause of status asthmaticus is a prolonged exposure to allergens (agents that cause allergies that usually cause asthmatic attack) or prolong respiratory infection.
Status Asthmaticus Trigger Factors
- House dust mite
- Food items such as sea food (shrimps)
- Peanut products such as Peanut snacks, peanut brittle etc
- Extremes of temperature
- Drugs such as NSAIDs (ibuprofen, diclofenac), aspirin, and beta blockers
- Viral and bacterial infections
- Sulfites used in preservation of drinks and in some coloring agents
- Chemicals such as pesticides, insecticides etc
- Emotional stress
Status Asthmaticus Symptoms
- Dyspnea (difficulty in breathing)
- Chest tightness
- Airway blockage
- No Wheeze there is silent chest
Status Asthmaticus Criteria for Diagnosis
- Silent chest on examination
- Unable to perform the PEF measurement
- Patient is unable to speak
- Presence of Cyanosis (bluish discoloration of buccal mucosa that is, the mouth turns bluish in color)
- Weak respiratory effort
- Bradycardia (slow heart beat)
- Pulsus paradoxus (exaggerated drop in systolic blood pressure during inspiration > 10 mmHg)
- Hypotension low blood pressure
- Severe Exhaustion
- Confusion or coma
- Arterial blood gases (ABG): Partial pressure of Carbon dioxide >5kPa, : Partial pressure of Oxygen <8kPa while pH will be low.
Status Asthmaticus Treatment Guidelines
In the treatment of status asthmaticus, there is immediate treatment and subsequent treatment. The immediate management is aimed at stabilizing the patient to prevent death while the subsequent management aims to return the patient to the initial normal level of respiration.
Status Asthmaticus Management (Immediate treatment)
- Give intravenous fluids (IV Fluids) for rehydration and calorie (Normal saline to alternate with dextrose saline)
- 60% concentrated Oxygen therapy by tight fitting facemask. The main aim of oxygen therapy is to raise the partial pressure of oxygen (PaO2 )to be greater than 8KPa in all patient and between 10 to 14 Kilopascals (KPa) in most patients if possible. The oxygen can be given using a nasal cannula or venturi-type mask to all patients with hypoxaemia until normal or near oxygen tension is achieved
- Use nebulized salbutamol: 2.5mg with or with 0.5mg ipratropium bromide
- Start glucocorticoid therapy by giving 30 to 60 mg of prednisolone orally or 200mg of hydrocortisone intravenously
- Request for urgent chest X-ray to exclude pneumothorax (presence of air in the pleural space) and shows hyperinflation
- Request for urgent blood gas or use pulse oximeter to assess the state of oxygen saturation in the lungs. In status asthmaticus, this is < 90%
- Use of Antibiotics, if there are signs of infection
Status asthmaticus subsequent treatment guideline and monitoring
- Close monitoring
- Continue giving oxygen (40-60%)
- Continue giving high doses of steroids: Oral prednisolone 30-60mg daily or IV hydrocortisone 200mg 6hourly (in seriously ill patients, or in those that are vomiting)
- If condition is improving, continue nebulized beta-2 (b2) agonists every 4hours
- If the patients condition is not improved after 15-30minutes, then repeat nebulization and add ipratropium bromide 0.5mg to the nebulizer solution
- If the progress is still unsatisfactory, consider giving aminophylline or parenteral b2-agonists – dosage of I.V Aminophylline infusion is 0.5mg/kg/hr. This is reduced to 0.2mg/kg/hour in those with disease. Dosage of I.V Salbutamol is 12.5mg/min or 3 to 20mg/min of I.V terbutaline
- Adjust infusion according to responses of Peak expiratory flow and Heart Rate
Status Asthmaticus Patients Monitoring
- Monitor the pulse rate and respiratory rate and speech of patient.
- Repeat measurement of peak expiratory flow (PEF), 30minutes after starting treatment and then 6 hourly.
- Measure and record the peak expiratory flow rate before and after beta-2 agonist administration
- Repeat measurements of arterial blood gas tensions within 2hours of commencing treatment if the initial PaO2 is <8KPa; or the initial PaCO2 was normal or raised; or when the patients condition deteriorates.
- Measure serum theophylline concentrations if theophylline is continued for >24horus. Aim at concentrations of 55 to 111 micromol /L (or 10-20microgram/ml)
When to take over Respiration of patients having Status Asthmaticus (Intensive care Treatment and use of Intermittent Positive Pressure Ventilation)
- Onset of exhaustion with signs of respiratory muscle fatigue
- Presence of respiratory distress
- Presence of Hypoxaemia with PaO2 < 6KPa
- Hypotension with Systolic Blood pressure of <90mmHg
- Confusion or drowsiness
- Patient in coma
- Respiratory and/or cardiac arrest
Indications for Mechanical ventilation in Patients with Status Asthmaticus
- Worsening hypoxia or hypercapnia
- Respiratory or cardiac arrest
Death from status asthmaticus mainly results from hypoxemia (due to low oxygen tension in the blood).