Individualize testing by history and exam. These are generally not needed for the low risk patients.
Consider:
Obtain pertussis
ECG<unk> ly observe on pulse oximetry (e.g. 1-3 hours)
Obtain pertussis
ECG<unk> ly observe on pulse oximetry (e.g. 1-3 hours)
CBC
Chem 10
Urinalysis
CXR
Pertussis nasal swab
RSV nasal swab
Consider:
Urine culture /BC
ECG
LP
LFTs
MRI Brain
Urine culture /BC
ECG
LP
LFTs
MRI Brain
See Definition in Background section
Age >60 days
Gestational age > 32 weeks and post-conceptional age >= 45 weeks
First BRUE ever
No prior BRUE or BRUE in clusters
BRUE duration <1 minute
No CPR by a medical provider
No concern for child abuse, family history of sudden<unk>  death,or toxic exposures
No abnormal physical findings: (bruising, cardiac murmurs, organomegaly)
No prior BRUE or BRUE in clusters
Brief resolved unexplained event
The differential diagnosis is extensive, and although a broad workup is often started in the ED including evaluation for sepsis, occult infection, and metabolic disorders, a cause is infrequently found[2]
Deterioration after intubation
Idiopathic 
Headache during pregnancy
GERD
Acute chest pain
Seizure