Acute severe asthma

Acute severe asthma is a severe bronchospasm in a patient with a history of asthma.

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What causes acute asthma?

• Asthma in history with emergency hospitalizations in the past.
• Respiratory tract infections.
• Trigger factors, such as stress, cold, exercise, smoking, allergen.
• Premature or newborns with low weight.

What are the symptoms of acute asthma?

Acute severe asthma is clinically expressed by the following symptoms:

• Peak expiratory flow rate (PEFR) <33-50% of the best or predicted, SpO2 <9 2%, PSE 120 bpm (<5 years) or> 130 bpm (2-5 years), BHC> 30 V min (> 5 years) or> 50 per min (2-5 years), the involvement of ancillary muscles in the act of breathing.

Life-threatening asthma: Any of the following in a patient with acute severe asthma:

• PEFR <33% of the best or predicted, SpO2 <92% or PaO2 <8 kPa (60 mmHg), normal RaCO2 (4.6-6 kPa, 35-45 mmHg), hypotension, exhaustion , confused consciousness or coma, dumb zones of pulmonary fields, cyanosis, easing of respiratory effort.

Almost fatal asthma:

• increased RACO2 and / or the need for mechanical ventilation
• Confused consciousness or drowsiness, maximal involvement of auxiliary muscles in the act of breathing, exhaustion, SpO2 <92% in air, CHSR 140 bpm, inability to speak.

How is acute asthma diagnosed?

• SpO2, PEFR or FEV1 (> 5 years).
• If the condition is critical: blood gases, chest X-ray, the level of theophylline in the plasma.

Differential diagnosis

The wheezing in the lungs can be of a different origin:

• bronchiolitis or croup; o Aspiration of a foreign body - asymmetry in auscultation;
• epiglottitis - after introduction into practice of the vaccine against Haemophilus influenzae B is very rare;
• pneumonia - can be both the primary cause of wheezing, and the trigger of an asthma attack;
• tracheomapacia.

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Immediate Action

Acute severe asthma:

• salbutamol 10 injections through the dispenser and adapter ± face mask or salbutamol inhaler (2.5-5 mg);
• prednisolone orally 20 mg (2-5 years), 30-40 mg (> 5 years) or hydrocortisone intravenously 4 mg / kg;
• Salbutamol should be repeated every 30 minutes, add ipratroprium bromide 250 μg with an inhaler every 20-30 minutes.

Life-threatening asthma:

• immediately salbutamol inhaler 2.5-5 mg;
• ipratropriuma bromide inhaler 250 mcg;
• hydrocortisone intravenously 4 mg / kg;
• bronchodilators every 20-30 minutes;
• epinephrine, sc / 10mkg / kg (solution 0.01 ml / kg 1: 1000, or 0.1 ml / kg 1:10 000).

Further management

• When improving - monitor SpO2, inhale prednisolone orally every 3-4 hours, for 3 days, transfer to a specialized department.
• If, despite the treatment, the condition worsens:
  • intravenously salbutamol, titrating by effect, up to 15 mcg / kg for 10 min, then infusion 1-5 mcg / kg / min;
  • aminophylline: loading dose 5 mg / kg, then intravenously infusion 1 mg / kg / h;
  • continue inhaling every 20 minutes;
  • think about the use of adrenaline (0, O2-0.1 mcg / kg / min);
  • magnesia sulfate intravenously 40 mg / kg (maximum 2 g).
• If respiratory failure increases: intubate, ventilate and transfer to a pediatric ICU.

Special Considerations

• In severe asthma with very high pressure in the airways, a decrease in the respiratory volume and irregular capnography curve, ventilation may be difficult.
• Manual ventilation with a low-stretch system may be required, but monitoring airway pressure, and especially inhalation pressure, will be extremely important. Pressure in the airways up to 30-40 cm H20 may be required. Increased pressure indicates the need for the most active use of bronchodilators.
• All inhalation anesthetics cause bronchial relaxation and can be useful in severe attacks. It is necessary to monitor the discharge of the used gas mixture.
• These children are usually dehydrated, and therefore the induction of anesthesia for intubation should be preceded by infusion preparation with crystalloids of 20 ml / kg. Slow administration of the preparations is preferable, but fast non-fasting patients may require rapid sequential induction. Propofol and ketamine are ideal.
• Peak expiratory flow rate in children: this is a simple method of measuring airway obstruction, which allows to determine the average or high severity of the disease. The measurement is carried out using a standard Wright peak meter.