Pulse oximetry in patients with pigmented skin: What I should know.

Pulse oximetry is widely used to non-invasively estimate the oxygen saturation of haemoglobin in arterial blood (SpO2). It is used widely throughout healthcare and was used extensively during the Covid-19 pandemic to detect and treat hypoxic patients. Research has suggested that pulse oximetry is less accurate in patients with darker skin. This led the US Food and Drug Administration agency (FDA) to issue a safety statement warning that pulse oximeters may be inaccurate when patients have pigmented skin. Evidence suggests that the oxygen saturation of arterial blood (SaO2) may be being overestimated by measuring SpO2 in those with pigmented skin. The degree of overestimation increases as SaO2 decreases especially when SpO2 reads below 80%. We review how pulse oximetry works and consider the implications for a patient's health when interpreting SpO2 in individuals with pigmented skin.

Can birth outcome inequality be reduced using targeted caseload midwifery in a deprived diverse inner city population? A retrospective cohort study, London, UK.

OBJECTIVES: (1) To report maternal and newborn outcomes of pregnant women in areas of social deprivation in inner city London. (2) To compare the effect of caseload midwifery with standard care on maternal and newborn outcomes in this cohort of women. DESIGN: Retrospective observational cohort study. SETTING: Four council wards (electoral districts) in inner city London, where over 90% of residents are in the two most deprived quintiles of the English Index of Multiple Deprivation (IMD) (2019) and the population is ethnically diverse. PARTICIPANTS: All women booked for antenatal care under Guys and St Thomas' National Health Service Foundation Trust after 11 July 2018 (when the Lambeth Early Action Partnership (LEAP*) caseload midwifery team was implemented) until data collection 18 June 2020. This included 523 pregnancies in the LEAP area, of which 230 were allocated to caseload midwifery, and 8430 pregnancies from other areas. MAIN OUTCOME MEASURES: To explore if targeted caseload midwifery (known to reduce preterm birth) will improve important measurable outcomes (preterm birth, mode of birth and newborn outcomes). RESULTS: There was a significant reduction in preterm birth rate in women allocated to caseload midwifery, when compared with those who received traditional midwifery care (5.1% vs 11.2%; risk ratio: 0.41; p=0.02; 95% CI 0.18 to 0.86; number needed to treat: 11.9). Caesarean section births were significantly reduced in women allocated to caseload midwifery care, when compared with traditional midwifery care (24.3% vs 38.0%; risk ratio: 0.64: p=0.01; 95% CI 0.47 to 0.90; number needed to treat: 7.4) including emergency caesarean deliveries (15.2% vs 22.5%; risk ratio: 0.59; p=0.03; 95% CI 0.38 to 0.94; number needed to treat: 10) without increase in neonatal unit admission or stillbirth. CONCLUSION: This study shows that a model of caseload midwifery care implemented in an inner city deprived community improves outcome by significantly reducing preterm birth and birth by caesarean section when compared with traditional care. This data trend suggests that when applied to targeted groups (women in higher IMD quintile and women of diverse ethnicity) that the impact of intervention is greater.

Pregnancy Outcomes and Blood Pressure Visit-to-Visit Variability and Level in Three Less-Developed Countries.

[Figure: see text].