1_26_09 Adverse Events

Adverse events in children with acute asthma discharged from the hospital with supplemental oxygen: a descriptive study

Pritchard J, Fassl B, Fletcher G, Nkoy F. University of Utah, Salt Lake City, Utah. Primary Children’s Medical Center, University of Utah, Department of Pediatrics, Division of Inpatient Medicine Salt Lake City, UT

Disclosure Statement Dr. Fassl has no affiliations or conflicts of interest to disclose

Background: Asthma and supplemental oxygen •

Hospital discharge with supplemental oxygen is common for other respiratory disorders: – Bronchiolitis • Safe • Cost effective

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Hospital discharge with supplemental oxygen for children with acute asthma is rare as it is rare and is regarded “risky” even if the clinical picture has improved: – Oxygen need is perceived as impending respiratory failure by many clinicians • Acute asthma symptoms largely resolved • Beta agonist spaced out

– Prolonged hospitalization due to oxygen requirement rather than asthma symptoms Home Oxygen After Observation May Be Acceptable for Children With Bronchiolitis Pediatrics. 2006;117:633-640 Home oxygen for children with acute bronchiolitis Arch Dis Child. 2008 Oct 16

Background: Asthma and hypoxia •

Hypoxia is common in children admitted for asthma exacerbations

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Causes of hypoxia – – – –

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Alveolar hypoventilation Diffusion impairment transport across the blood-gas barrier Presence of a shunt Ventilation – perfusion imbalance (V/Q mismatch): most common cause

Critical asthma affects medium sized airway – Decreased alveolar ventilation – Decrease in alveolar pO2 and increase in pCO2 – Hypoxia and hypercarbia • Correlating clinical picture: – Sign of global respiratory insufficiency – Critically ill patient

Background: Asthma and supplemental oxygen • Many children with asthma have a significant Oxygen requirement but are clinically well appearing – Other processes besides a decrease in the minute ventilation responsible for hypoxia: • Diffusion impairment across the blood-gas barrier: viral infections • V/Q mismatch

Study purpose • To describe disease and hospitalization characteristics of otherwise healthy children with acute asthma discharged on home oxygen • To determine 30 day hospital readmission, ED visits • To describe adverse events in children with discharged on oxygen – ICU admission rates, death

Study location • Primary Children’s Medical Center (PCMC) • Tertiary Care Referral Center • 1 million children catchment area • 232 bed hospital • 250 annual admissions for asthma exacerbations

Study design/methods • Retrospective study – Children admitted with primary dx of asthma 1997-2006, 493.xx

• Inclusion criteria: – Primary dx asthma – Home oxygen

• Exclusion criteria: – – – –

Chronic cardiopulmonary diseases Home oxygen at baseline Technology dependent children Medically complex children* Srivastava et al., Pediatr Clin North Am. 2005 Aug;52(4):1165-87 …

Methods – Data sources/analysis •

Enterprise data warehouse: administrative database for all Intermountain healthcare facilities – –

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Admission/Readmission/ED visits Financial data, hospitalization data

3 step chart review: • Step 1: Review of all charts primary dx asthma 1997-2006 – Home oxygen y/n – Exclusion criteria • Step 2: Detailed review of charts of children discharged on home oxygen – Patient characteristics – Viral co-infection: testing, documentation of URI symptoms – Medications – 2 reviewers: • Inter-rater reliability kappa >0.8 on all data elements on 30 charts • Step 3: Review of readmissions

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Descriptive data analysis

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IRB approval

Results: study population Total # of admissions with primary dx asthma 1997-2006 n=2056

D/c on oxygen n=171

Excluded n=41

Study population n=130; 6,3%

D/c not on oxygen n=1885

RESULTS: Patient characteristics • Median age: 4y (range 2-13) • Race: – 83% caucasian, 8% hispanic

• Gender: – 54% male – 46% female

RESULTS: Hospitalization characteristics • Median LOS: 63h (9-334) • Median Hospitalization cost: $ 2,952 ($ 339- $ 19,832) • APR – DRG Severity of illness index: – – – –

54% SOI 1 40% SOI 2 4% SOI 3 1% SOI 4

• PICU admission: 5/132 (4%)

Results: Oxygen at discharge Flow (116/130)

Median

Range

0.5 lpm

0.05-3.6 lpm

Highest recorded O2 1 lpm flow in preceding 24h

0-6 lpm

Last documented

0-6 lpm

0.4 lpm

While sleeping only 68/130 (52%)

Delivery route

Nasal can 125/130 Blow by 3/130 Not spec 2/130

Hospitalization characteristics: Viral testing • Viral testing: – 49/130 (38%): viral testing – 17/49 (35%): positive viral test • 9 RSV • 6 Influenza • 2 Parainfluenza

• Viral symptoms: – 75/130 (58%): URI symptoms – 12/130 (9%): Clinical diagnosis bronchiolitis

Results: Secondary Diagnosis • Status asthmaticus (38) 31.7% • Pneumonia (18) 15.0% • Viral infection (RSV, acute URI) (27) 21% • Hypoxia/hypoxemia (15) 12.5% • Dehydration (3) 2.5% • Otitis media (2) 1.7%

Hospitalization characteristics: Medication Use During Hospitalization • • • •

Albuterol 100.0% Systemic Steroids 90.2% Ipratropium 65.9% Inhaled Corticosteroids: 40% – Preadmission: 22%

Hospitalization characteristics: Medications at Discharge • • • •

Albuterol 93% Systemic Steroids 73% Ipratropium 18% Inhaled Corticosteroids: 56%

Results: Adverse events and Readmission •

Hospitalization within 30 days – 5/130 (4%) • 2/130 for asthma/resp diagnosis • 3/130 other unrelated diagnosis (ulnar fx, hernia repair, MVA) • Earliest readmission: 16 days after discharge – Re- exacerbation

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ED/Urgent care visit within 30 days – 13/130 (10%) patients; 15 ED/urgent care encounters – 9/130 visits for asthma • Elapsed time – – – –

Median 18 days 1 patient within 1 day 1 patient within 2 days Original asthma symptoms worse

– Re-exacerbation episode in 7/130

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No reported death or ICU admission

Discussion • Readmissions rare and late in study population – Timing: not related to initial asthma episode

• ED/urgent care visits frequent: – 2/130 worsening of initial asthma episode – 7/30 Re-exacerbation within 30 days: • Failure of preventive measures

• High variability in oxygen flow and deeming someone ready for d/c on oxygen • Viral co-infections – URI symptoms prevalent

• Preventive measures

Limitations • • • •

Single center study Retrospective Descriptive; no control group Administrative data for patient identification – Only Intermountain facilities – SOI determined through administrative data only

• No clinical information after discharge in most children • No clinical information about asthma control

Conclusion • Discharge on supplemental oxygen may be feasible in children who have clinically improved asthma symptoms but require oxygen • Future studies: – Control group – Prospective randomized controlled study needed to confirm safety of this measure