Developmental outcome at 6.5 years after acidosis in Term Newborns

1. Developmental outcome at 6.5 years after acidosis in Term Newborns SCH medics Journal Club Thursday 12th July 2012 Faith Harries

2. Aim To evaluate whether metabolic acidosis at birth in term infants who appear healthy is associated with long term developmental abnormalities

3. Objectives Search for relevant literature to the clinical question Select a useful paper to discuss Is the paper valid and reliable enough to answer the question? Does clinical practice need to change?

4. Case presentation Whilst on call a midwife rings the neonatal team to tell them that Baby S has had a cord gas which shows a pH 7.01 – is there anything the neonatal team want to do? Baby S is a term baby who was delivered by emergency LSCS for foetalbradycardia. He needed no resuscitation, had good apgars and is now with his mother on the postnatal ward. He appears healthy and well.

5. The clinical question In children who were born full term and were apparently healthy (P), is metabolic acidosis (I) associated with long-term developmental abnormalities (O).

6. Literature search [Metabolic acidosis OR acidosis] AND [developmental outcome] = 76 search results Further search using [Metabolic acidosis OR acidosis] AND developmental outcome OR neurodisability] = 28 results Resource searched: Medline

7. Developmental Outcome at 6.5 years After Acidosis in Term Newborns: A Population-Based Study Maria Hafström, SivEhnberg, Sofia Blad, HåkanNorén, Cecilia Renman, Karl GustafRosén and IngemarKjellmer Pediatrics 2012;129;e1501

8. Current practice Paired cord gases are not routinely recommended Taken when there are concerns about the baby in labour or immediately after the birth Well babies with acidosis on gases are reviewed by neonatal team

9. Methods Prospective observational study (Gothenburg and surrounding areas) Intrapartum fetal surveillance introduced – continuous evaluation of the ST segment of the fetal ECG combined with carditocography (CTG) analysis STAN methodology 2 year period (October 2000 – September 2002) 14687 term deliveries 2 groups identified 78 had cord artery metabolic acidosis (group A) Metabolic acidosis defined = umbilical artery pH < 7.05 and base deficit > 12.0 mmol/L Control cases identified (group B)

10. Methods (2) Infants placed into four groups according to their treatment need in the neonatal period Children were identified using Swedish national registration system and school health database system Records scrutinised for developmental data, referral actions or proceedings for specific educational support Data extraction, evaluations and categorisation were performed independently by 2 paediatricians who were blinded to the conditions at birth Difference in the two groups was calculated by using the Mann-Whitney nonparametric test Χ2 distribution test used to analyse the frequency of the different categories in the different acidotic groups and the control group

11. Flowchart for the study population

12. Neurodevelopmental Categorization Criteria

13. Outcome measures • Numbers undergoing ordinary healthcare follow-up • Numbers undergone special development assessment • Age at assessment • Mortality • Lost to follow-up numbers • Head circumference at 18 months • Weight, height and BMI at 6.5 years

14. CRITICAL APPRAISAL SKILLS PROGRAMME Making sense of evidence about clinical effectiveness A Are the results of the study valid? Screening Questions 1. Did the study address a clearly focused issue? YES 2. Did the authors use an appropriate method to answer their question? YES - a prospective cohort study using a control group

15. Detailed questions 3. Was the cohort recruited in an acceptable way? YES 4. Was the exposure accurately measured to minimize bias? NO – categorisation of being healthy in the neonatal period is partly a subjective judgment, physician chose the level of care needed and the level of follow-up. 5. Was the outcome accurately measured to minimize bias? CAN’T TELL – physician made subjective judgement initially though all acidotic infants who developed a neurodevelopmental diagnosis were treated in the SCBU and assigned to this follow-up. Outcome data was collected retrospectively – though matching of controls was done prospectively

16. 6 A. Have the authors identified all important confounding factors? YES – subjective judgment of physician, blinding the paediatricians to the conditions at birth B. Have they taken account of the confounding factors in the design and/or analysis? YES – all acidotic infants who developed a neurodevelopmental diagnosis were treated in the SCBU and assigned to this follow-up; the same nurse examined all of the notes; matched paired analysis was omitted because 11 of 78 allocation groups was not complete

17. 7A Was the follow up of subjects complete enough? CAN’T TELL – minor neurodevelopmental problems at this age may not be discovered/reported B Was the follow up of subjects long enough? NO – this age group have only been in school for 0.5-1 year, problems may manifest after more time

18. B What are the results? 8. What are the results of this study? All infants in this study who were born with metabolic acidosis who appeared healthy at birth and who were not treated in the SCBU were without neurological diagnosis at 6.5 years of age 9. How precise are the results? Small confidence intervals were used and showed no significance when comparing the healthy infants to the control group. 10. Do you believe the results? YES

19. Will the results help me locally? 11. Can the results be applied to the local population? YES – we have national guidelines on when cord gases should be taken (NICE); children in the UK attend school from an earlier age and problems will have usually been noted/reported by 6.5 years of age 12. Do the results of this study fit with other available evidence? YES – systematic review and meta-analysis have shown that a low arterial cord pH showed strong, consistent and temporal associations with clinically important neonatal outcomes that are biologically plausible. (BMJ 2010;340:c1471)

20. Summary and Conclusion The first prospective cohort study to determine whether metabolic acidosis (as defined) affects the developmental outcome in apparently healthy term newborns. CLINICAL BOTTOM LINE Neonates who appear well after perinatal metabolic acidosis do not have an increased risk of neurological or behavioural problems at the age of 6.5 years