Journal Club 17/09/13 Rob Morton. Heliox Therapy in Bronchiolitis: Phase III Multicentre double...
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Transcript of Journal Club 17/09/13 Rob Morton. Heliox Therapy in Bronchiolitis: Phase III Multicentre double...
Journal Club17/09/13
Rob Morton
Heliox Therapy in Bronchiolitis:Phase III Multicentre double blind RCT
Chowdhury et al. Pediatrics 2013; 131:661-669
Bronchiolitis season in Sheffield
Photo removed for copyright reasons
Bronchiolitis season in Sheffield
Photos removed for copyright reasons
Heliox
• Airways in bronchiolitis oedematous and inflamed, lined/blocked with mucus.
• Mix of 21% O2 and 79% Helium- Lighter than air or O2.
• Promotes laminar rather than turbulent flow in congested airways. Also has a higher CO2/02 binary coefficient, may promote alveolar gas exchange.
• Safe, inert
• ? Cheap- $70 dollars a canister- 3-5 canisters a day• = £219 per day
Heliox Cochrane review(2010)Liet et al. Heliox inhalation therapy for bronchiolitis in infants. Cochrane Database Syst Rev.
2010(4):DD006915
• 4 trials including children < 2 years• All on intensive care units• 3 studies showed improvements in symptoms scores at 1 hr
of age• Concluded insufficient evidence, need for a large RCT
BREATHE trial(The Bronchiolitis Randomized Controlled Trial Emergency-Assisted Therapy with Heliox—
An Evaluation )
•4 centres- UK & Australia
• ? 3 Bronchiolitis seasons 2005-2008
Inclusion Criteria
• All infants (<12months) with clinically diagnosed bronchiolitis by a doctor from A&E or wards
• O2 sats <93% in airor
• “Respiratory distress”
• Requiring hospital admission
Randomised to 2 groups
Intervention
• “Heliox” via tight fitting face mask• Nasal cannulae if not tolerated• CPAP if requiring >4L/min O2
flow rate (mask), or >2L/min (NC)
“Controls”
• “Airox”- same delivery criteria
Outcomes
Primary• “Length of time to alleviate hypoxia and respiratory distress”- time
from start of trial gas to clinical stability out of O2 for 1 hour
Secondary• Proportion of each treatment group requiring CPAP• Woods asthma score
CASP(Critical Appraisal Skills Programme)
• 1. Did the trial address a clearly focused issue?
• Yes/No. • Does Heliox improve length of treatment in bronchiolitis?• Is that the relevant issue? Length of stay more important.• ? Severe/ mild bronchiolitics?
• 2. Was the assignment of patients to treatments randomised?
• ?Yes
• Randomised but ?? not all accountable
• ? Not all patients eligible approached for trial?
• 4 centres, 3 seasons = 30 bronchiolitics per year.Adelaide has a population of 1.3million, Sheffield 0.5 million!
• 3. Were all of the patients who entered the trial properly accounted for at the end of the trial?
• ?Yes
But…
Is it worth continuing??
• ………?...........Yes
• 4. Were patients, health workers and study personnel “blind” to the treatment?
• Yes- Good blinding process. Canisters A & B.
• ? Any smell to heliox? Presumably not.
• 5. Were the groups similar at the start of the trial?
Were the groups similar?
• Admitted from A&E? How are they fed? Bottle/ NG/ IV?
• Previous bronchiolitis
• Time from start of symptoms? Time since admission?
• Co-morbidities?
• 6. Apart from the experimental intervention, were the groups treated equally?
• ?- No mention of feeds, other cares. As study well blinded we can presume they were equal across the 2 groups.
• How much O2 was required in each group, how severe were the patients? % O2 has an effect on use of Heliox.
What are the results?
• 7. How large was the treatment effect?
What are the results?
Outcomes
• Length of treatment- Decreased in group who tolerated facemask, particularly those who are RSV+ve.
• If tolerates facemask, and RSV+ve, LOT 1.46 vs 2.01 days, reduces length of treatment by 0.5 days
• ? Decreases need for CPAP (not statistically significant and small numbers)
• “ Reduced respiratory distress”, significant from 8 hrs.?? Take their word for it.
• 8. How precise was the treatment effect?
• No Confidence intervals, IQR instead, as using medians.
What are the results?
9. Can the results be applied to our local population?
• Developed country, same patients and pathology
• Standard care does not usually involve facemasks or CPAP on wards.
• No comparison to standard care.
• ? Can be used for bronchiolitics who are RSV +ve, if they can tolerate a face mask. May prevent need for CPAP & HDU admission?
10. Were all the clinically important outcomes considered?• No.
• Length of treatment of limited use as no comparison to normal care. Need to know length of stay in hospital (impossible to do in this study as no admission/ discharge times)
• Eg., does the intervention/ mask lead to a decrease in feeds and prolong admission?
• How much heliox was used?
11. Are the benefits worth the harms and costs?• How much Heliox was actually used?
5 canisters seems a lot per day/ per patient.= $350 per day/ £223Best intervention group = £312 (1.4 days)
• How much extra cost for the nursing care to fit face mask?
• How much cost for the additional HDU beds?
So….How should a bronchiolitis trial be done?
SABRE: Hypertonic Saline in Acute Bronchiolitis: A Randomised Controlled Trial and Economic Evaluation
BREATHE
• O2 <93% or resp distress • No time limit to recruit• No time of discharge• No economic evaluation
SABRE
• O2 <92% on admission• Strict 90 minute limit to recruit• Criteria for “SABRE” fit for
discharge- includes feeds• Full economic evaluation
Questions?