Pediatric Reactive Airway Disease Workup

Updated: May 09, 2018
  • Author: Eric S Chin, MD; Chief Editor: Kirsten A Bechtel, MD  more...
  • Print
Workup

Laboratory Studies

A complete blood count (CBC) may be indicated for a suspected viral infection (lymphocytosis, leukopenia), parasitic infection (eosinophilia), or hemosiderosis.

An arterial blood gas (ABG) determination should be performed for any patient in status asthmaticus to check for hypoxia, hypercarbia, or acidosis; alternatively, a venous blood gas measurement can be used to assess for hypercarbia and acidosis and combined with pulse oximetry monitoring.

An assessment of electrolyte levels may reveal hypokalemia in patients who are using albuterol.

Although theophylline is prescribed less frequently, a theophylline level is useful for those on the drug.

Next:

Imaging Studies

Routine radiography does not need to be part of the initial routine evaluation of asthma. [14]

Consider chest radiography if increased temperature, absence of family history of asthma, and the presence of localized wheezes or rales.

  • Hyperinflation

  • Peribronchial thickening

  • Atelectasis

  • Radiographs may provide evidence of foreign body, associated vascular anomalies, cardiac enlargement, pulmonary hypertension, infiltrates, or masses.

Previous
Next:

Other Tests

See the list below:

  • All chronically wheezing infants and children with chronic asthma should have a sweat chloride test for cystic fibrosis at a subsequent primary care provider (PCP) visit or during inpatient evaluation.

  • A tuberculosis skin test may be indicated if significant risk factors exist.

  • Allergy testing

  • Exercise tolerance testing

Previous
Next:

Procedures

Procedures include the following:

  • Spirometry (decreased forced expiratory volume in one second [FEV1])

    • Bedside spirometry is the primary procedure for children with RAD who are older than 5 years.

    • Patients with decreased FEV1 require further evaluation and treatment.

  • A barium swallow may be indicated to determine any esophageal, pulmonary, or vascular pathology, particularly a tracheoesophageal fistula.

  • Bronchoscopy (rarely indicated) (see Table 1 below)

  • Peak expiratory flow (PEF) is the most common form of pulmonary function test monitoring. Record the best of 3 attempts. Possible life-threatening asthma exacerbation with PEF predicted of less than 30%; severe exacerbation, with less than 50%; and moderate exacerbation, with less than 80%.

Peak flow rates are described in the table below.

Table 1. Peak Flow Rates in Liters per Minute [15] (Open Table in a new window)

Height in

Inches

Average

Rate

Range*

Height in

Inches

Average

Rate

Range*

40

150

110-190

56

330

240-420

41

160

115-205

57

340

240-420

42

170

120-220

58

360

260-460

43

180

130-220

59

375

270-480

44

190

135-245

60

390

280-500

45

200

145-255

61

400

290-510

46

210

150-270

62

415

300-530

47

220

160-280

63

430

310-550

48

230

165-295

64

445

320-570

49

240

175-305

65

460

330-590

50

250

180-320

66

480

345-615

51

260

190-330

67

500

360-640

52

270

195-345

68

515

370-660

53

280

200-360

69

530

380-680

54

300

215-385

70

550

395-705

55

315

225-405

71

570

410-730

*Includes 95% of white males aged 7-20 years.

Derived and adapted from J Pediatr 1979;95:192-6.

Previous