The remaining oxygen is used slowly and the body can survive submersion for a longer period of time before irreversible anoxic tissue damage develops. Experience indicates that saltwater and freshwater aspiration do not produce significantly different respiratory injury patterns. If large amounts are swallowed, hypo or hypernatremia may result from fresh or salt water submersions, respectively. Respiratory infection is possible, but antibiotics should be reserved for proven infection or when grossly contaminated water is aspirated. In the first moments after rescue, the appearance of the child who has nearly drowned may range from apparently normal to apparently dead.
Body temperature is frequently low, even in temperate, warm-water environments.
Respiratory efforts may be absent, irregular, or labored, with pallor or cyanosis, retractions, grunting, and cough productive of pink, frothy material. The lungs may be clear, or there may be rales, rhonchi and wheezing. Infection may develop as a consequence of aspirated mouth flora or organisms in stagnant water, but this is not usually important in the first 24 hours. Respiratory function may improve spontaneously or deteriorate rapidly as pulmonary edema and small airway dysfunction worsens. Neurologic assessment may show an alert, normal child or any level of CNS compromise.