Highlights from the literature

Abstract

The vaLue of a puLse oximeTer Spotting cyanosis reliably has always been considered to be a clinical challenge for some, especially in children with darker pigmented skins. The pulse oximeter has had a huge impact on clinical medicine and is often thought of as the fifth ‘clinical sign’. Lucina was impressed by this study from Graham H et al. [EClinical Medicine 2019 DOI: https:// doi. org/ 10. 1016/ j. eclinm. 2019. 10. 009] where they evaluated the epidemiology of hypoxaemia (defined as haemoglobin oxygen saturations of less than 90% as measured by pulse oximetry) and oxygen use in hospitalised neonates and children in Nigeria. This prospective cohort study examined 23 926 neonates and children (<15 years of age) who were admitted to 12 secondarylevel hospitals, during a 2 year study period. They identified the prevalence of hypoxaemia, oxygen use, and clinical predictors of hypoxaemia. Using a generalised linear mixedmodels they calculated the relative odds of death Surprisingly pooled hypoxaemia prevalence was 22.2% (95%CI 21.2 to 23.2) for neonates and 10.2% (9.7–10.8) for children. Hypoxaemia was common among children with acute lower respiratory infection (28.0%), asthma (20.4%), meningitis/encephalitis (17.4%), malnutrition (16.3%), acute febrile encephalopathy (15.4%), sepsis (8.7%) and malaria (8.5%), and neonates with neonatal encephalopathy (33.4%), prematurity (26.6%), and sepsis (21.0%). Hypoxaemia increased the adjusted odds of death 6fold in neonates and 7fold in children. Clinical signs predicted hypoxaemia poorly, and their predictive ability varied across ages and conditions. Hypoxaemic children received oxygen for a median of 2–3 days, consuming ∼3500 L of oxygen per admission. This study highlights the fact that hypoxaemia is common in respiratory and nonrespiratory acute childhood illness. Most importantly it emphasises that hypoxaemia increases the risk of death substantially. They confirmed that clinical signs recorded during routine care were indeed particularly poor at predicting hypoxaemia in children and neonates with nonrespiratory conditions, having much lower sensitivity for hypoxaemia in nonrespiratory conditions than respiratory conditions. The predictive value of the WHO combination of signs for hypoxaemia was reasonably good for child pneumonia, but was much poorer for nonrespiratory conditions (particularly for children over the age of 1 year). Given the limitations of clinical signs highlighted, pulse oximetry is an essential tool for detecting hypoxaemia, and should be part of the routine assessment of all hospitalised neonates and children