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Acute Severe Asthma
Theme Symposium
ACUTE SEVERE ASTHMA Radha Rajagopalan*, Suchitra Ranjith** and Rajeswari*** From the: Head of Paediatrics Department & Director Medical Education*, Head Paediatric Intensive Care Unit**, Registrar, PICU***, Apollo Hospitals, 21 Greams Lane, off Greams Road, Chennai 600 006, India. Correspondence to: Dr. Radha Rajagopalan, Head of Paediatrics Department & Director Medical Education, Apollo Hospitals, 21 Greams Lane, off Greams Road, Chennai 600 006, India.
Table: Acute Severe Asthma.
Oxygen to maintain saturation >90-95% Nebulization salbutamol 3 doses at 20 min. intervals Wt <20 kg: 0.5 mL with 3 mL N saline Wt >20 kg: 1 mL with 3 mL N saline Nebulised Ipratropium <1 yr: 1 mL (combined with salbutomol x 3) Steroids: Methylprednisolone 2 mg/kg stat IV followed by 1 mg/kg Q 6H Add H2 blocker
↓
↓
↓
Improved
Not improved
↓
↓
↓
Hrly nebulization with salbutamol 3-4 doses
Injection Magnesium sulfate* 25-50 mg/kg in 10 mL saline over 20 min may repeat after 6 hrs
↓
↓
Reassess diagnosis
↓
May increase Neb. interval to 2-4 hrly and continue steroids
Terbutaline 0.05-0.1 mg/kg/min infusion Continue nebulisations Not improved
↓ Aminophylline infusion (reduce terbutaline infusion by 50%)
↓ May consider Isoprenaline infusion and Mechanical ventilation * 1 mL 50% magnesium sulfate = 500 mg.
DEFINITIONS
RISK FACTORS
ACUTE severe airway obstruction in a patient with airway hyper responsiveness, which fails to respond to usual treatment.
• •
Apollo Medicine, Vol. 2, No. 4, December 2005
304
Poorly controlled asthamatics. Two or more hospitalizations for asthma in the past year.
Theme Symposium
• • •
Use of >2 canisters/month of inhaled short acting β2 agonist. Frequent ER visits more than three in a month. Previous mechanical ventilation in asthma.
DANGER SIGNS AND INDICATIONS FOR INTUBATION • • • • •
•
Ipratropium acts synergistically with salbutamol and should always be combinbed.
•
Steroids must be administered systematically, never nebulise.
VENTILATION STRATEGIES
Altered sensorium. Cynasosis in 60% oxygen. Respiratory fatigue. Silent chest. Rapidly rising PCO2 or high normal PCO2 in the face of tachypnea.
•
Pressure or volume controlled ventilation with high flow rates.
•
Target PEEP to level of auto PEEP.
•
Prolonged expioratory time to prevent air trapping.
•
Permissive hypercapnia to limit plateau pressures <3035 cm H2O.
•
Adequate deep sedation to control tachypnea and continue bronchodilatation.
GOAL AND PRINCIPLES OF THERAPY • • •
To maintain adequate oxygenation. To prevent and treat airtrapping:bronchodilatation. To reduce airway inflammation:steroids.
REFERENCES 1. Helfaer MA, Nichols DG, Rogers MC. Lower airway disease; Bronchiolitis in asthma. In: Rogers MC (ed). Textbook of Pediatric Intensive Care. 3rd edn. Baltimore: Williams and Wilkins, 1996: p. 127-164.
POINTS TO REMEMBER •
Always give solbutamol with oxygen to offset pulmonary hypoxic vasoconstriction and worsening hypoxia.
305
2. Spyros Papiris, Anastesia Kotanidou. Severe asthma. Critical Care 2002 Feb; 6(1).
Apollo Medicine, Vol. 2, No. 4, December 2005
ACUTE SEVERE ASTHMA Radha Rajagopalan*, Suchitra Ranjith** and Rajeswari*** From the: Head of Paediatrics Department & Director Medical Education*, Head Paediatric Intensive Care Unit**, Registrar, PICU***, Apollo Hospitals, 21 Greams Lane, off Greams Road, Chennai 600 006, India. Correspondence to: Dr. Radha Rajagopalan, Head of Paediatrics Department & Director Medical Education, Apollo Hospitals, 21 Greams Lane, off Greams Road, Chennai 600 006, India.
Table: Acute Severe Asthma.
Oxygen to maintain saturation >90-95% Nebulization salbutamol 3 doses at 20 min. intervals Wt <20 kg: 0.5 mL with 3 mL N saline Wt >20 kg: 1 mL with 3 mL N saline Nebulised Ipratropium <1 yr: 1 mL (combined with salbutomol x 3) Steroids: Methylprednisolone 2 mg/kg stat IV followed by 1 mg/kg Q 6H Add H2 blocker
↓
↓
↓
Improved
Not improved
↓
↓
↓
Hrly nebulization with salbutamol 3-4 doses
Injection Magnesium sulfate* 25-50 mg/kg in 10 mL saline over 20 min may repeat after 6 hrs
↓
↓
Reassess diagnosis
↓
May increase Neb. interval to 2-4 hrly and continue steroids
Terbutaline 0.05-0.1 mg/kg/min infusion Continue nebulisations Not improved
↓ Aminophylline infusion (reduce terbutaline infusion by 50%)
↓ May consider Isoprenaline infusion and Mechanical ventilation * 1 mL 50% magnesium sulfate = 500 mg.
DEFINITIONS
RISK FACTORS
ACUTE severe airway obstruction in a patient with airway hyper responsiveness, which fails to respond to usual treatment.
• •
Apollo Medicine, Vol. 2, No. 4, December 2005
304
Poorly controlled asthamatics. Two or more hospitalizations for asthma in the past year.
Theme Symposium
• • •
Use of >2 canisters/month of inhaled short acting β2 agonist. Frequent ER visits more than three in a month. Previous mechanical ventilation in asthma.
DANGER SIGNS AND INDICATIONS FOR INTUBATION • • • • •
•
Ipratropium acts synergistically with salbutamol and should always be combinbed.
•
Steroids must be administered systematically, never nebulise.
VENTILATION STRATEGIES
Altered sensorium. Cynasosis in 60% oxygen. Respiratory fatigue. Silent chest. Rapidly rising PCO2 or high normal PCO2 in the face of tachypnea.
•
Pressure or volume controlled ventilation with high flow rates.
•
Target PEEP to level of auto PEEP.
•
Prolonged expioratory time to prevent air trapping.
•
Permissive hypercapnia to limit plateau pressures <3035 cm H2O.
•
Adequate deep sedation to control tachypnea and continue bronchodilatation.
GOAL AND PRINCIPLES OF THERAPY • • •
To maintain adequate oxygenation. To prevent and treat airtrapping:bronchodilatation. To reduce airway inflammation:steroids.
REFERENCES 1. Helfaer MA, Nichols DG, Rogers MC. Lower airway disease; Bronchiolitis in asthma. In: Rogers MC (ed). Textbook of Pediatric Intensive Care. 3rd edn. Baltimore: Williams and Wilkins, 1996: p. 127-164.
POINTS TO REMEMBER •
Always give solbutamol with oxygen to offset pulmonary hypoxic vasoconstriction and worsening hypoxia.
305
2. Spyros Papiris, Anastesia Kotanidou. Severe asthma. Critical Care 2002 Feb; 6(1).
Apollo Medicine, Vol. 2, No. 4, December 2005