Titrate to an arterial oxygen saturation >90% (>95% in pregnant women and with coexistent heart disease)
Favor continuous nebulization to decrease the chance of admission when compared to intermittent dosing
Nebulizer
Intermittent: 2.5-5mg q20min x3, then 2.5-10mg q1-4hr as needed OR
Continuous: 0.5mg/kg/hr (max 15mg/hr)
If using intermitent nebs at home PTA, start on continuous
MDI
6-12 puffs q20min up to 4h, then q1-4hr as needed
Levalbuterol is pure R-enantiomer, whereas racemic albuterol as above is 50:50 mix of R and S albuterol
Most clinical studies fail to show benefit over racemic albuterol
Levalbuterol at 5x the cost, may not warrant the small benefits seen in some studies
In severe<unk>  exacerbation, be aware of lactic acidosis that develops due to pathology and the added lactic acidosis from albuterol,
Manifests as worsening respiratory distress, tachypnea, compensatory increase in ventilation
Ensure adequate intravascular volume, but carefully volume expand as<unk><unk>  may increase ADH secretion
Rarely, clinically important hypokalemia, alongside hyperglycemia and leukocytosis, may result from repeated beta agonists and sympathomimetics
Intermittent: 2.5-5mg q20min x3, then 2.5-10mg q1-4hr as needed OR
Continuous: 0.5mg/kg/hr (max 15mg/hr)
If using intermitent nebs at home PTA, start on continuous
6-12 puffs q20min up to 4h, then q1-4hr as needed
Most clinical studies fail to show benefit over racemic albuterol
Manifests as worsening respiratory distress, tachypnea, compensatory increase in ventilation
Ensure adequate intravascular volume, but carefully volume expand as<unk><unk>  may increase ADH secretion
0.25-0.5mg q20min x2-3 doses
Only shown to be effective in the<unk>  setting to reduce hospitalization rates and improve lung function
No benefit of adding to inpatient, hospitalized regimens
Should be given in the first hour with effects to reduce admission and rate of relapses
Dexamethasone
As effective as prednisone especially in children 
Single dose dexamethasone may be equally effective to 5 days of prednisone in adults
0.6mg/kg IV or PO (max 16mg); 2nd dose 24hr later
Prednisone
40-80mg/day in one or two divided doses x5d
Methylprednisolone
1mg/kg IV q 4–6hr
Only use IV if cannot tolerate PO since equal effectiveness between dosing routes
Oral and IV steroids are safe during pregnancy (though technically Category C)
Inhaled corticosteroids may be considered as a rescue effort for severe<unk> , given over a 90 min period
Nebulized fluticasone 500 µg q15 min
Nebulized budesonide 800 µg q30 min
As effective as prednisone especially in children 
Single dose dexamethasone may be equally effective to 5 days of prednisone in adults
0.6mg/kg IV or PO (max 16mg); 2nd dose 24hr later
40-80mg/day in one or two divided doses x5d
1mg/kg IV q 4–6hr
Only use IV if cannot tolerate PO since equal effectiveness between dosing routes
Oral and IV steroids are safe during pregnancy (though technically Category C)
Nebulized fluticasone 500 µg q15 min
Nebulized budesonide 800 µg q30 min
25-75 mg/kg over 30 min (2-3 gm IV in most adults)
Duration of action approximately 20 min, beware of hypotension in rapid administration due to smooth muscle relaxation mechanism
In patients with moderate to severe<unk>  there is a decreased rate of admission with an NNT of 2
High-dose, prolonged magnesium may expedite discharge from the ED in non-infectious<unk>  in pediatric study
50 mg/kg/hr for 4 hours
MAX 8,000 mg for 4 hours, monitor for cardiopulmonary complications
No interventions or discontinuations of magnesium sulfate due to adverse events in the study
NNT of 2-3, for hospital discharge before 24 hours
50 mg/kg/hr for 4 hours
MAX 8,000 mg for 4 hours, monitor for cardiopulmonary complications
No interventions or discontinuations of magnesium sulfate due to adverse events in the study
NNT of 2-3, for hospital discharge before 24 hours
Inhalation is preferred route of administration, but adequate drug delivery to small airways may be hampered in severe attacks
Terbutaline and epinephrine can be administered IM/IV/SubQ
Need to monitor for arrhythmias, tachycardia, hypertension, cardiac ischemia
1:1000 0.01 mg/kg (max 0.5mg) subQ  or IM Q20min x3
Nebulized racemic epinephrine 0.03 mL/kg (2.25% solution) diluted in 3-5 mL NS via jet nebulizer q3-4hr PRN shown to be as safe as nebulized albuterol
In severe, life-threatening<unk> , IV epinephrine may be safe to consider, substantiated only by a case series of adults in 2003, however
Longer-acting beta2-agonist promoting bronchodilation
Caution in elderly/CHF with greater potential for cardiotoxicity
0.25mg subQ/IM q20min x 3
Then followed by infusion at 1 µg/kg/min, titrated up by increments of 1 to max of 10 1 µg/kg/min
Elevated troponins q4hrs during infusion, more common in cTnI vs. cTnT, with EKG changes of ischemia should prompt re-evaluation for stopping infusion
Some experts have nebulized IV form
5 mg of IV form terbutaline
However, significantly higher cost than albuterol
Then followed by infusion at 1 µg/kg/min, titrated up by increments of 1 to max of 10 1 µg/kg/min
Elevated troponins q4hrs during infusion, more common in cTnI vs. cTnT, with EKG changes of ischemia should prompt re-evaluation for stopping infusion
5 mg of IV form terbutaline
However, significantly higher cost than albuterol
Consider as alternative to intubation
Alleviates muscle fatigue which leads to larger tidal volumes
May drive nebulized treatments deeper into airways
Maximize inspiratory support
Inspiratory pressure 8
PEEP 0-3, only enough to match patient's auto-PEEP
Inspiratory pressure 8
PEEP 0-3, only enough to match patient's auto-PEEP
Relative indications include worsening hypercapnea, exhaustion, altered mental status, CO2 narcosis without any specific number endpoint on blood gases, refractory hypoxemia, status<unk> ticus
Consider induction with Ketamine
Provides bronchodilation and sedation however it does promote secretions
Ketamine is the preferred induction agent for intubation in an<unk> tic.
Dosing 1-2mg/kg
Ventilation of<unk> tic patients requires deep sedation
Benzos, propofol, or ketamine (1mg/kg/hr)
Avoid long-term administration of neuromuscular blocking agents such as succinylcholine for prolonged periods in ICU (>12 hours), if possible, given higher rates of complication
A large ET tube is preferred (>8.0 mm)
Provides bronchodilation and sedation however it does promote secretions
Ketamine is the preferred induction agent for intubation in an<unk> tic.
Dosing 1-2mg/kg
Benzos, propofol, or ketamine (1mg/kg/hr)
Avoid long-term administration of neuromuscular blocking agents such as succinylcholine for prolonged periods in ICU (>12 hours), if possible, given higher rates of complication
A large ET tube is preferred (>8.0 mm)
Initial ventilation settings - severe<unk> 
Assist-control ventilation
Resp rate
Start slow to avoid air-trapping
RR ~ 8-10 in adults
Goal: obtaining a pH above 7.2 and plateau pressure below 30 cmH2O
If Pplat >30 must lower respiratory rate
If Pplat under 30 cannot be maintained, other causes of decreased respiratory system compliance must be considered (i.e. pneumothorax, misplaced endotracheal tube, pulmonary edema, etc.)
May require "permissive hypoventilation"
Sacrifice MV for full exhalation
Lower I:E ratio
Low peak pressure/avoidance of breath stacking more important than correcting CO2 
Tidal volume 6-8mL/kg ideal wt
PEEP 0-5 cmH2O
Flow rate 80-100L/min
Keep FiO2 minimum to achieve SpO2 > 90%
Use bronchodilators even when intubated
Monitor for breath stacking (inspiratory holds, plateau pressures)
Most common cause of post-intubation hypotension
Check ventilator tracing
Assist-control ventilation
Resp rate
Start slow to avoid air-trapping
RR ~ 8-10 in adults
Goal: obtaining a pH above 7.2 and plateau pressure below 30 cmH2O
If Pplat >30 must lower respiratory rate
If Pplat under 30 cannot be maintained, other causes of decreased respiratory system compliance must be considered (i.e. pneumothorax, misplaced endotracheal tube, pulmonary edema, etc.)
May require "permissive hypoventilation"
Sacrifice MV for full exhalation
Lower I:E ratio
Low peak pressure/avoidance of breath stacking more important than correcting CO2 
Tidal volume 6-8mL/kg ideal wt
PEEP 0-5 cmH2O
Flow rate 80-100L/min
Keep FiO2 minimum to achieve SpO2 > 90%
Start slow to avoid air-trapping
RR ~ 8-10 in adults
If Pplat under 30 cannot be maintained, other causes of decreased respiratory system compliance must be considered (i.e. pneumothorax, misplaced endotracheal tube, pulmonary edema, etc.)
Sacrifice MV for full exhalation
Lower I:E ratio
Low peak pressure/avoidance of breath stacking more important than correcting CO2 
Most common cause of post-intubation hypotension
Check ventilator tracing
Disconnect ventilator
Decompress chest
Consider empiric bilateral chest tubes or rapid ultrasound to identify pneumothorax
IVF bolus
Administration of antibiotics only when physical exam or ancillary testing supportive of bacterial infection
Antibiotics may be considered for select patients and may improve symptoms and peak expiratory flow, further understanding needed to identify which patients may be most likely to benefit 
60 to 80% helium is blended with 20 to 40% oxygen
Heliox improves non laminar flow and may increases the diffusion of carbon dioxide by improving ventilation
Not indicated for<unk>  treatment
Zafirlukast (20 mg bid) and montelukast (10 mg/day)
Acute asthma exacerbation
Pulmonary
COPD exacerbation
Airway obstruction
Acute chest syndrome
Anaphylaxis
Acute dyspnea
Angioedema