Acute Asthama

Acute Asthama

oxygen
pefr
pulse oximetry
abg
albuterol nbi
steroids iv
cxr
chem7

if pco2 becomes normal or increases or pt becomes drowsy
intubate
maintainnance- on albuterol, and sodium cromoglycate and RASt test

if pt found to be allergic hyposensitisa

Acute asthma.
Diagnose by history and physical examination.

History.
Onset, trigger of current exacerbation.
Severity of symptoms, including limitation of exercise tolerance, interference with sleep.
Medications.
Prior hospitalizations, ER visits, especially recent visits.
Severe exacerbations in past, requiring ICU admissions, intubation.
Any other chronic medical conditions.

Physical examination.
Severity of respiratory compromise: speech difficult because of breathlessness, use of accessory muscles of respiration, inability to lie supine, pulsus paradoxus >12 mm Hg fall in systolic BP during inspiration, tachycardia, tachypnea.
Complications: pneumonia, pneumothorax, pneumomediastinum.
Cyanosis, level of alertness, air movement, wheezing. Wheezing can be an unreliable guide to degree of obstruction; severe obstruction may be associated with a 'silent chest' because of little or no air movement.
Beware if patient seems too calm. This may represent CO2 retention and narcosis.
Functional assessment. Monitor PEFR or FEV1. Check pulse oximetry. Infants become hypoxemic earlier than adults do, and physical assessment of respiratory status in children is less reliable. Check O2 saturations on all infants and children by pulse oximetry. Room air saturation should be >93%. A room air saturation <91% in infants usually is predictive of the need for hospitalization. Check an arterial or capillary blood gas level on infants with O2 saturation <90%.

Lab tests.
Do not delay initial treatment waiting for lab tests and radiographs. After initial stabilization, consider:
CBC if patient has fever or purulent sputum.
CXR if suspect complication such as pneumonia or pneumothorax.
Serum theophylline concentration in all patients taking theophylline.
ABG in patients with severe distress, poor response to treatment, or abnormal pulse oximetry.

High-risk patients. Patients at high risk of asthma-related death or life-threatening deterioration.
Prior intubation for asthma, or prior ICU admission.
Two or more hospitalizations for asthma in past year.
Three or more ER visits in past year.
Hospitalization or ER visit in past month.
Using or withdrawing from systemic corticosteroids.
History of syncope or seizure related to hypoxia from asthma.
Poor social situation or psychiatric disease.
Infant <1 year old.
<10% improvement in PEFR or FEV1 in ER.
PEFR or FEV1 <25% predicted.
PCO2 40 mm Hg or more. A normal PCO2 is abnormal in the setting of asthma exacerbations where the patient should be hyperventilating, resulting in a low PCO2. A normal PCO2 may herald impending respiratory failure.

Treatment for asthma or COPD.
Oxygen may be needed to support patient and should not be withheld even to do a blood gas analysis.
Hydration is without benefit if the patient is euvolemic, and aggressive IV hydration may precipitate CHF.
If severe asthma, consider cardiac monitoring.
Beta-agonists are the mainstay of treatment.
Albuterol. 2.5 mg in 3 ml of NS by nebulizer (adults). May give up to 4 treatments per hour. Some studies suggest that continuously nebulized albuterol works better.
In children, can use albuterol 0.15 to 0.3 mg/kg by nebulizer every hour (ideally divided every 20 minutes or given continuously over 1 hour). The 0.3 mg/kg dosing is significantly better in moderate to severe asthma.
Can use nebulized albuterol almost continuously if needed.
Tachycardia does not increase further after first several doses.
May cause hypokalemia by shifting K1 intracellularly.
Metered-dose inhaler by means of a spacer is just as good as nebulizer if you give about 6 to 8 activations by a spacer to equal one nebulized treatment.
Steroids.
Reduces return visits, admission rates.
Should be used in most patients: always in those already receiving steroids and in most of those previously receiving medications who fail to clear after one nebulizer treatment.
Methylprednisolone. For adults 125 mg IV and 40 mg IV Q6h. For children 1 to 2 mg/kg IV followed by 2 mg/kg/24 hours divided into Q6h doses.
Prenisone. For adults 60 mg PO. For children 0.5 to 2.0 mg/kg Q24h for 3 to 7 days.
All evidence indicates that steroids given orally are just as effective as IV in acute exacerbations of asthma.
There is no need for a steroid taper in those not previously receiving steroids if only 5- to 7-day course. There is no increase in relapse without taper and no adrenal suppression with a 1-week course.
Anticholinergics seem to work better in COPD than asthma but do have some bronchodilating effect.
Atropine 0.4 to 2 mg (adult 0.025 mg/kg) by nebulizer. May mix with beta-agonists in same nebulizer. May increase heart rate and may cause pupils to dilate from contact with mist.
Ipratropium can be used by metered-dose inhaler and is available in a nebulized form. The dose is 0.5 mg by nebulizer. This is preferred over atropine, since there is little systemic effect.
Theophylline-aminophylline. There is little evidence that adding theophylline-aminophylline to maximized beta-adrenergic therapy is helpful in the treatment of acute asthma.
Is arrhythmogenic.
Has a very low therapeutic threshold.
Always check a drug level if you feel compelled to use this drug.
Takes 2 to 3 hours to peak effect after IV administration.
Although frequent, optimal doses of beta-blockers are more effective, if you choose to use aminophylline, it is a 6 mg/kg loading dose to maximum of 350 mg over 30 to 45 minutes followed by a drip at 0.6 mg/kg/hr not to exceed 50 to 60 mg/hr. Levels should be checked. Maintenance dose dependent on patient's smoking status, presence of cor pulmonale, and age.
Magnesium sulfate is shown in some studies to produce transient improvement in asthma.
Reasonable if patient has failed conventional therapy; less toxic than theophylline.
Dose: In adults 2 g IV over 15 to 20 minutes (may mix in 50 ml of normal saline). Very safe but do not use in renal failure. May get flushing, transient hypotension but rare.
Magnesium sulfate has been successfully used in children. The dose is 25 mg/kg.
Intubation and nasal CPAP (continuous positive-pressure ventilation) are a last resort and may not work well in the asthmatic patient.
Admit if persistent respiratory distress, O2 saturation <94% after treatment (children), peak expiratory flow of <60% of predicated value in children or failure to increase by 15% above baseline or absolute value of 200 L/min in adults, failure of FEV1 to increase by 500 cc or produce a total of <1.6 liters (adults), hypercapnia (retaining CO2 over baseline value), or pneumothorax. Additionally, clinical judgment is important. If the patient does not look well or still feels dyspneic, consider admission to hospital.