Management of Asthma: Emergency Department/Hospital Management (C3)

VETERANS HEALTH ADMINISTRATION CLINICAL PRACTICE GUIDELINE FOR THE MANAGEMENT OF COPD OR ASTHMA

Management of Asthma: Emergency Department/Hospital Management (C3)

A. Is There a Life-Threatening Alternative Diagnosis? - Is acute shortness of breath due to an alternative life-threatening diagnosis, e.g., pulmonary edema, obstructed upper airway, anaphylaxis, epiglottiditis, pneumonia, pulmonary embolus or pneumothorax? For pregnancy, criteria for admission, intubation, etc., may differ in order to minimize fetal distress. (Refer to Diagnosis Module of Asthma C1.) For patients in acute respiratory distress with neither an alternative diagnosis nor established asthma, presumption should be for a diagnosis of asthma.

B. Assess Severity and Initiate Inhaled Short Acting Beta2-Agonist and Oxygen

Classifying Severity of Asthma Exacerbation

	Mild	Moderate	Severe	Respiratory Arrest Imminent
Symptoms: Breathless Preferred position	While walking Can lie down	While talking Prefers sitting	While at rest Sits upright
Talks in:	Sentences	Phrases	Words
Alertness	May be agitated	Usually agitated	Usually agitated	Drowsy or confused
Signs: Respiratory rate	Increased	Increased	Often > 30/minute
Use of accessory muscles; suprasternal retractions	Usually not	Commonly	Usually	Paradoxical thoraco-abdominal movement
Wheeze	Moderate, often only end expiratory	Loud throughout exhalation	Usually loud throughout inhalation and exhalation	Absence of wheeze
Pulse/minute	< 100	100 to 120	> 120	Bradycardia
Pulsus paradoxus	Absent < 10 mmHg	May be 10 to 25 mmHg	Often present > 25 mmHg (adult)	Absence suggests respiratory muscle fatigue
Functional Assessment: PEF/FEV₁ (percent of personal best or percent predicted)	80 percent	Approximately 50 to 80 percent	< 50 percent of personal best or predicted or response lasts < 2 hours
PaO₂ (on air)	Normal (test usually not necessary)	> 60 mmHg (test usually not necessary)	< 60 mmHg possible cyanosis
Pa CO₂ (on air)	< 42 (test usually not necessary)	42 mmHg (test usually not necessary)	>/= 42 mmHg possible respiratory failure
SaO₂ percent (on air) at sea level	95 percent (test not usually necessary)	91 to 95 percent	< 91 percent

Risk factors for life-threatening exacerbations of asthma include: history of severe asthma, poorly controlled asthma of any severity, atopy, psychological factors, failure by the patient or patient's physician to recognize severity of asthma, and daily use of corticosteroids. Previous hospitalization for asthma and history of intubation with mechanical ventilation for asthma increase the likelihood that patient will require in-hospital care.

Most patients with severe asthma hyperventilate in proportion to the severity of the attack and use accessory muscles during inspiration and expiration; diffuse wheezes and rhonchi are frequently present during both phases of respiration as well. Hypoventilation or a silent chest are signs of imminent respiratory arrest.

Absolute PaCO₂ is not a good indicator of severity; change in level may be more significant. Some patients suffer respiratory arrest at high, others at relatively normal levels of PaCO₂. Prolonged severe asthma can result in a metabolic acidosis, another ominous sign. Increased work of breathing associated with severe asthma in the elderly or in patients with other chronic disease lowers the threshold for intubation.

Severely stressed patients who are barely able to speak should not be asked to perform FEV₁ and/or PEF. In patients who can perform these tests, they are usually < 50 percent personal best or predicted in severe asthma.

Laboratory tests may be useful in following severe asthma and diagnosing comorbid states. Consider CBC with differential, electrolytes, phosphate, magnesium, ionized calcium, lactate levels, arterial blood gas, chest x-ray, EKG.

Inhaled beta2-agonist by MDI withholding chamber or nebulizer. See Annotation F for dosages.

C. Impending Respiratory Failure - Impending respiratory failure may be indicated if any of the following are present:

Altered level of consciousness (severe agitation, confusion, obtundation, or coma)
Cyanosis or severe hypoxemia (PaO₂< 60 mmHg; SaO₂ < 90 percent; on room air at sea level)
Paradoxical thoracoabdominal movement
Silent chest on auscultation (absence or cessation of wheeze)
Bradycardia
Exhaustion

D. Consider Intubation and Admit to ICU - Suggested initial strategies for stabilization may include:

100 percent nonrebreather face mask
Continuous SaO₂ monitor
Inhaled short acting beta2-agonist hourly or continuously with the addition of anticholinergic for selected patients
Intravenous access, correct hypovolemia if present, but avoid over hydration
Intravenous corticosteroids (120 to 240 mg per day, see Annotation F)
Laboratory and other diagnostic studies as indicated: consider CBC, electrolytes, ABG, chest radiograph, EKG, theophylline level
Consider noninvasive positive pressure ventilation.

Respiratory failure or respiratory arrest:

Endotracheal intubation
Sedation; neuromuscular blockade (NMB) may be considered in some patients in order to achieve ideal patient-ventilator interaction
100 percent FiO_2.

Guidelines for ventilation:

Aim for adequate gas exchange with minimal peak inspiratory pressure (PIP)

Minimize tidal volumes (5 to 8 ml/kg)
Adjust inspiratory flow rate, respiratory rate and I:E ratio to allow adequate ventilation and minimize PIP
Use permissive hypercapnia to avoid barotrauma associated with high-peak inspiratory pressures
Keep arterial pH > 7.1: PaCO₂ < 120 mmHg; PIP < 50cm H₂0
(< 30 cm H₂O optimal) as long as hemodynamically stable
Sedate for optimal patient-ventilator interaction

Elevate head at > 30 degrees
Utilize neuromuscular blockade only if providers are experienced in its use

TABLE OF EVIDENCE Utility of Intensive Care, Mechanical Ventilation and Alternative Management Strategies in Severe Asthma

Intervention	References	Grade of Evidence	Strength of Recommendation
Intensive care, intubation, mechanical ventilation, continued pharmacologic treatment and neuromuscular blockade are effective in management of severe asthma	Bramane 1990 Beveridge, 1996 Bishop 1993 NAEPP, Expert Panel Report 2, 1997 Zimmerman 1993 JTFPP, 1995 LeSon 1995 Burrows 1995 Jagoda 1997 Bellomo 1994	C	1
Noninvasive positive pressure ventilation may be a safe alternative to intubation	Meduri 1996 Pollach 1995	B	2b
Permissive hypercapnia is safe and reduces peak inspiratory pressures	Hickling 1994 Smith 1988 Tuxen 1982; 1992 Dries 1995	C	2a
Pharmacologic intervention	Jagoda 1997	C	1a

E. Is there an Immediate Good Response to Treatment? - In a good response, all three are present.

FEV₁ or PEF 70 percent of personal best
No distress
Physical exam: normal

F. Consider Alternative Diagnoses; Initiate Pharmacologic Therapy - Dosages of drugs for asthma exacerbation in emergency medical care or hospitalized patients.

(Adapted from the NAEPP Expert Panel Report 2)

Medications	Adult Dose	Comments
*Inhaled short-acting beta2-agonist* Albuterol: MDI (90 g/puff) with spacer/holding chamber	4 to 8 puffs every 20 minutes or 24 puffs per hour; then every 1 to 4 hours as needed.	As effective as nebulized therapy if patient is able to coordinate inhalation maneuver.
OR
Nebulizer solution: (5 mg/mL)	2.5 to 5 mg every 20 min for 3 doses, then 2.5 to 10 mg every 1 to 4 hours as needed, or 10 to 15 mg/hour continuously.	Only selective beta2-agonists are recommended. For optimal delivery, dilute aerosols to minimum of 4 mL at gas flow of 6 to 8 L/minute
Bitolterol: Nebulizer solution (2 mg/mL)	See albuterol dose.	Has not been studied in severe asthma exacerbations. Do not mix with other drugs.
MDI (370 g/puff)	See albuterol dose.	Has not been studied in severe asthma exacerbations.
Pirbuterol: MDI (200 g/puff)	See albuterol dose.	Has not been studied in severe asthma exacerbations.
*Systemic (injected) beta2-agonist* Epinephrine: 1:1000 (1 mg/ml)	0.3 to 0.5 mg every 20 min for 3 doses sq.	No proven advantage of systemic therapy over aerosol. May be hazardous in patients with coronary artery disease.
*Anticholinergics* Ipratropium bromide: MDI (18 mg/mL)	4 to 8 puffs as needed.	Dose delivered from MDI is low and has not been studied in asthma exacerbations.
OR
Nebulizer solution: (0.25 mg/mL)	0.5 mg every 30 minutes for 3 doses then every 2 to 4 hours as needed.	May mix in same nebulizer with albuterol. Should not be used as first line therapy; may be added to beta2-agonist therapy.
*Corticosteroids* Prednisone Methylprednisolone Prednisolone	120 to 240 mg/day in 3 or 4 divided doses for 48 hours, then 60 to 80 mg/day until PEF reaches 60 percent of personal best or predicted.	For outpatient "burst" use 40 to 60 mg in single or 2 divided doses for adults for 3 to 10 days. See note.

Note: No advantage has been found for higher dose corticosteroids in severe asthma exacerbations, nor is there any advantage for intravenous administration over oral therapy provided gastrointestinal transit time or absorption is not impaired. The usual regimen is to continue the frequent multiple daily dosing until the patient achieves an FEV₁ or PEF of 50 percent predicted or personal best and then lower the dose to twice daily. This usually occurs within 48 hours. Therapy following a hospitalization or emergency department visit may last from 3 to 10 days. If patients are then started on inhaled corticosteroids, studies indicate there is no need to taper the systemic corticosteroid dose. If the follow-up systemic corticosteroid therapy is to be given once daily, one study indicates it may be more clinically effective to give the dose in the afternoon at around 3:00 p.m. (Beam et al. 1992).

TABLE OF EVIDENCE Dosage and Route of Bronchodilators

Intervention	References	Grade of Evidence	Strength of Recommendation
Anticholinergic therapy with beta2-agonist is no better than beta2-agonist alone	O'Driscoll et al. 1989 Higgins 1988 Mc Fadden 1997 Fitzgerald 1997 Karpel 1996	A	2b
Albuterol delivered by MDI with spacer or nebulizer are equivalent in patients capable of cooperating	Colacone 1993 Wildhaber 1997 Chou 1995	B	1a
Intermittent and continuous nebulization are equivalent	Reisner 1995 Lin 1993 Rudnitsky 1993	B	2a

TABLE OF EVIDENCE Dosage and Route of Corticosteroid Therapy

Intervention	References	Grade of Evidence	Strength of Recommendation
Oral and parenteral administration has the same results provided normal absorption	Ratto 1988 Harrison 1986 Hoffman 1988	A	1
Steroid dosage 120 to 180 mg Prednisone or equivalent	Tanaka 1982 Marquette 1995 Haskell 1983 Emmerman 1995 Raimondi 1986	A	1
ER setting use effective	Schneider 1988 Littenberg 1986 Chapman 1991	A	1

G. Is There a Good Response, FEV₁/PEF > 70 Percent - In a good response, all four are present:

FEV₁ or PEF 70 percent of personal best or predicted
Response sustained 60 minutes since last treatment
No distress
Physical exam: normal

H. Treat with Short-Acting Beta2-Agonists; Systemic Corticosteriods; Reassess at 1 to 3 Hours

Inhaled short-acting beta2-agonist every 60 minutes
Systemic corticosteroids
Continue treatment for 1 to 3 hours, provided there is improvement

I. Is There an Incomplete Response? - In an incomplete response, either is present:

FEV₁ or PEF 50 percent but < 70 percent
Mild-to-moderate symptoms

J. Is the PaCO₂ < 42 and the Patient Alert? - In a poor response, any one is present:

FEV₁ or PEF < 50 percent
PaCO₂ 42 mmHg
Symptoms: severe breathlessness
Physical exam: drowsiness, confusion

K. Patient Stable and Improved

Patient Stable and Improved
PaCO₂ < 42 mmHg
FEV₁ or PEF > 50 percent
Symptoms: mild-to-moderate
Physical Exam: alert with no more than moderate wheezing

L. Admit or Continue on Hospital Ward

Administer inhaled beta2-agonist by MDI 4 to 8 puffs with spacer/holding chamber every 1 to 4 hours, or by nebulizer.
Administer inhaled anticholinergic in patient intolerant of beta2-agonist. For dosages see Annotation F.
Administer systemic (oral or intravenous) corticosteroids. For dosages, see Annotation F.
Administer oxygen
Monitor FEV₁ or PEF, O₂ saturation, pulse, and respirations

Hospital Checklist for Inpatients with Asthma Exacerbations

Intervention	Dose/Timing	Education/Advice
Inhaled medications (MDI) + spacer/holding chamber) Beta2-agonist Corticosteroids	Select agent, dose, and frequency (e.g., albuterol, 2 to 6 puffs every 3 to 4 hour prn; inhaled corticosteroid, 16 to 24 puffs per day of beclomethasone or equivalent	Teach purpose Teach technique Emphasize need for spacer/holding chamber Check patient technique
Oral medications	Select agent, dose and frequency (e.g., prednisone 20 mg bid for 3 to 10 days	Teach purpose Teach side effects
Peak flow meter	Measure PEF a.m. and p.m. and record best of three tries each time	Teach purpose Teach technique Distribute peak flow diary
Follow-up visit	Make appointment for follow-up care with primary clinician or asthma specialist within 7 days of discharge	Advise patient (or caregiver) of date, time and location of appointment
Action plan	Before or at discharge	Instruct patient (or caregiver) on simple plan for actions to be taken for symptoms, signs, and PEF values suggesting recurrent airflow obstruction

M. Does Patient Have a Sustained Improvement?

Minimal symptoms
FEV₁/ PEF > 70 percent of personal best or predicted
Demonstrates understanding and skills in hospital checklist (see Annotation N)

N. Provide Education; Discharge From Hospital - Home management.

Reinforce self-management action plan
Arrange for follow-up
Review medication use:

Continue treatment with inhaled beta2-agonist
Continue course of oral corticosteroids
Initiate inhaled corticosteroids with holding chamber at dose appropriate to severity (12 to 20 puffs of beclomethasone for moderate and > 20 puffs for severe per day or equivalent dose of another agent)

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