At autopsy of a newborn suspected to be stillborn, both lungs float freely in water even though the child never breathed. Which of the following BEST explains this false positive hydrostatic test?

• A Aspiration of amniotic fluid during labour
• B Postmortem absorption of water by the lungs
• C Residual surfactant lowering lung density
• D Gas produced by putrefaction within the lung tissue ✓

Explanation

Putrefactive bacteria generate gas within the lungs and gastrointestinal tract of a corpse, and these gases can float even completely unaerated, stillborn lungs, giving a falsely positive hydrostatic test. Putrefaction must therefore be excluded by examining the degree of decomposition elsewhere in the body before accepting a positive result. Aspirated amniotic fluid adds weight rather than buoyancy, surfactant does not make solid fetal lung float, and water absorption would increase weight and cause sinking.

Reference: Modi's Medical Jurisprudence and Toxicology, 23rd ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.