Why Dewi Evans Diaphragm Splinting is a Myth.

The cause of death for baby C was ‘widespread hypoxic/ischaemic damage to the heart/myocardium’ due to lung disease, with maternal vascular under perfusion as a contributory factor.

This is the one-sentence summary of a detailed pathology report on the death of baby C. If we break it down, widespread means diffuse, not focal or localised, as would be the case with a heart attack. Diffuse changes are normally part of a systemic process, such as infection and inflammation.

Damage to the heart/myocardium means that the cells of the heart, in general, but muscle pump cells in particular, were so damaged they ceased to function adequately, making death inevitable. Lung disease caused this fatal outcome. The lung diseases were respiratory distress syndrome (RDS) and pneumonia, both diagnosed before death. RDS has an extraordinarily high mortality, and the reported mortality of both perinatal and nosocomial pneumonia is still high, ranging from 20%–50%

At 30 weeks, the lung is in the saccular stage. This period develops from 26 to 28 to 32-36 weeks. The saccules enlarge with gestational age to provide a larger, more flexible, efficient end product called the alveolus. The alveolar stage lasts from 32 to 36 weeks of gestational age until more or less 2 years of life. Thus, premature delivery and the start of breathing interrupt the normal development of the alveoli and pulmonary vasculature of these infants, preventing gas exchange. Only after 27 weeks do the terminal Alveoli develop the capacity to readily provide oxygen and remove carbon dioxide. Contrary to Evan's claim that neonatology is much the same as he practised it, newer research provides willing clinicians with deeper insight into the pathology and treatment of immature lungs.

Despite all this knowledge and the facts presented in the case, Dewi Evans invented a new disease while giving evidence. Evans said in court, and not once in any of his written reports that Letby killed baby C by injecting air into the nasogastric tube. Not only is the idea preposterous, but it is also physically impossible, given Baby C's circumstances. Evans committed perjury on the court, proved himself a quack and underscored yet again his profound ignorance of science.

Baby C was under Continuous Positive Airways Pressure (CPAP). CPAP works by different physiological mechanisms but mainly acts to increase the Functional Residual Capacity of the lungs. The application of pressure forces the immature lungs to remain open during expiration when the baby. The lungs, therefore, never fully deflate, and a reserve of air or an air/ oxygen blend remains throughout the respiratory cycle. Gas flowing from the ventilator provides new oxygen and washes out carbon dioxide. It is CPAP that braces (or splints) the entire thoracic cavity, massively reducing the work of breathing required by the neonate.

Newton's third law of motion states that for every action (force) in nature, there is an equal and opposite reaction. Pressurised lungs exert a force on the adjacent diaphragm, which exerts an equal and opposite force on the lungs. CPAP works by splinting the diaphragm!

Of course, it's possible to over-pressurise the lungs, but that would not lead to an unexpected collapse.

If the newborn cannot sustain the extra work of breathing to meet its respiratory needs, respiratory failure follows. This failure may manifest as impaired oxygenation (cyanosis) or ventilation (respiratory acidosis), both present in baby C; then, without prompt intervention, a respiratory arrest is imminent. If respiratory arrest happens, cardiac arrest will follow, which caused the death of baby C.

Is it a mere coincidence that Sandie Bohin is just as stupid about physics as Dewi? Or did they copy each other's homework?

I think we should be told.