Hypoxic and Hypercapnic Events in Young Infants During Bed-Sharing

SCH Journal Club

Elspeth Ferguson

ST5 Paediatrics

Aim• To determine if there is any difference in

physiological parameters of bed-sharing and non-bed sharing infants during sleep

Objectives• To search the literature for relevant articles• Select a relevant paper to discuss• Determine validity and reliability of paper

in answering clinical question• Discuss how this information may affect

our clinical practice

What we know about SIDS• 300 deaths/year• Risk factors

–Prematurity–LBW–Smoking–Sleep environment

What is the mechanism of SIDS• Not well understood• Presumed particular vulnerability• ?Upper airway compromise• ?Hypoxia• ?Abnormalities of brainstem function

Current Advice for Parents• Back to sleep• Feet to foot• Don’t smoke• Don’t share a bed• Baby to sleep in your room for first 6 months• Don’t let your baby get too hot• Breastfeed• ?dummy

Clinical Question• P Infants• I Bed-sharing (co-sleeping)• C Cot-sleeping (non co-sleeping)• O Hypoxia/Hypercapnia

• Study design Case-control study

Hypoxic and Hypercapnic Events in Young Infants During Bed-Sharing

Baddock, S.A., Galland, B.C., Bolton, D.P.G., Williams, S.M & Taylor, B.J

Pediatrics 2012 130:237-244

Methods• 40 bed-sharing infants, 40 cot-sharing

infants• Monitoring over 2 nights in home

environment– Video recordings– Physiological recordings– Maternal questionnaire for demographic data

Outcome Measures• Desaturation events

– <90% ≥1second

• Re-breathing events– CO2 >3%

• CO2 exposure– CO2 >2/3/4% ≥ 3 seconds

CASP Analysis• 1. Did the study address a clearly focused

issue?

✓Yes

• 2. Did the authors use an appropriate method to answer their question?

✓Yes

3. Were the cases recruited in an acceptable way?

• Media advertising & Postnatal groups– Who responds to adverts?– Who attends postnatal groups?– ?incentives

4. Were the controls recruited in an acceptable way?

• Postnatal ward• Different group from bed-sharing

individuals – why?• Matched for age and season of study

5. Was the exposure accurately measured to minimise bias?

• Bed-sharing at least 5 hr per night • ?how this was determined• Regularly• Blinding not possible

– ?infants affected by monitoring equipment– ?mother’s actions altered

6. Confounding factors• Matched for age and season of recruitment• Smoking• Alcohol• Drug use• Birth weight• Gestation• Socioeconomic status• Method of feeding

What are the results? & How precise are they?

• Desaturation events– BS 255 VS CS 123– Characteristics of events comparable– Mean events per infant BS 6.8 (0-44) VS CS 3.1 (0-

16)– Relative risk of event 2.17(1.75 – 2.69) – When adjusted for temperature RR 1.54 (1.17-2.02)– 1 degree increase in temperature = 60% increase in

desaturation events (95% CI 31-96)

What are the results? & How precise are they?• Rebreathing events

– Infants experiencing episodes BS 22 VS CS 1– Median rebreathing per night = 19min– Majority associated with head covering– Increases in heart rate and respiratory rate observed

What are the results? & How precise are they?• CO2 exposure

– Infants exposed to ≥ 2% CO2 BS 27 VS CS 2

9. Do you believe the results• Significantly more desaturations in bed-

sharing infants• Temperature seems to have a key role• Significance values for raised CO2 and

rebreathing episodes unclear

10. Can the results be applied to the local population?

• Majority of European descent• Socio-economic status or group• Rates of breast-feeding

11. Do the results of this study fit with other available evidence?

• Suggest sleep ‘events’ more frequent in bed-sharing

• Highlights importance of temperature regulation

• May suggest a mechanism by which bed-sharing leads to an increased risk of SIDS

Summary• Bed-sharing infants experience more

episodes of desaturation, rebreathing and raised CO2 exposure than cot-sleeping infants

• BUT are these episodes of concern?