Pediatric emergency medicine trisk 354

TABLE 71.9
DIAGNOSTIC STUDIES FOR EVALUATION OF RESPIRATORY
DISTRESS


Test

Indications

Pulse oximetry

Respiratory distress,
failure

Capnography

ABG, VBG

Comments

Measures oxygen
saturation
Relative
contraindication if
agitation will
worsen distress
Not reliable if severe
anemia
No information about
ventilation
Respiratory distress,

Measures end-tidal
failure
CO2 , CO2
Confirm, monitor
waveform
endotracheal tube
Can be used in
placement, ventilatory
intubated or
failure
nonintubated
Diagnose, differentiate
patients
upper and lower
Approximates ABG
airway obstruction,
Paco2 if
monitor therapeutic
cardiovascular
interventions
status intact; Etco2
Monitor ventilation
values 2–5 mm Hg
during sedation
Characteristic
waveforms for
apnea,
hypoventilation,
obstruction

Respiratory distress,
Information about
failure, acidosis,
ventilation
carboxyhemoglobin,
Most useful for lower
methemoglobin
airway process
Relative
contraindication if


CBC count, blood cx, CSF
analysis, cx, mono
spot/EBV titers

Infection, allergy

Electrolytes, BUN, CR,
glucose, Ca, PO4 , Mg,
LFTs, ammonia, TFTs

Metabolic/endocrine
disease, metabolic
disturbance, disease
Altered mental status
Tetany
Bleeding/clotting
disorder, pulmonary
embolism

PT/PTT

d-dimer
Toxicologic screen blood,
urine

Nasal, ocular, rectal swab:
DFA, PCR, cx

Pulmonary embolism
Ingestion/intoxication

agitation will
worsen distress
ABG, VBG changes
occur late and may
not be seen until
arrest
(A-a) O2 gradient
increase suggests
ventilation–
perfusion mismatch
Relative
contraindication for
lumbar puncture if
agitation or
positioning will
worsen distress
Calculate anion gap

Negative d-dimer
excludes PE in
patients with low
pretest probability
for PE

Central nervous
system depressants,
neuromuscular
blockade, electron
transport chain
poisons
Bronchiolitis, Chlamydia Neonates, infants
infection, pertussis,
viral pneumonia


Sputum: stains, cx

Bacterial, TB,
pneumocystis, fungal
TB skin test
TB
Neck radiograph, AP/lateral Tracheitis, abscess,
foreign body

Adolescents

Not necessary for the

diagnosis of croup
Relative
contraindication if
unstable airway
Consider portable if
unstable

Chest radiograph AP/lateral Lower respiratory
disease, atelectasis,
foreign body,
barotrauma, effusion,
mass, chest wall
trauma/deformity,
cardiac process
Forced expiratory or
Foreign body
Air trapping distal to
bilateral decubitus
foreign body
Unilateral decubitus
Distinguish effusion
Effusion layers
from infiltrate
Abdominal radiograph,
Abdominal mass,
supine/prone, cross-table
obstruction,
lateral, upright)
perforation
Fluoroscopy

Upper airway
obstruction; structural
or functional
anatomic, foreign
body, paralysis vocal
cords, diaphragm
Laryngoscopy/bronchoscopy Upper or lower airway
Esophagoscopy for
obstruction; structural
esophageal
or functional, foreign
processes
body
Head CT scan
Intracranial bleed, mass,