Should an inspiration occur in the act of vomiting, the vomitus may pass into the air-passages; a similar accident may occur in a person who attempts to swallow and speak at the same time. Infants have been suffocated by inspiring vomited milk. Fitz[886] states that food may pass from the digestive tube to the air-passages after death.
A case of suffocation in an infant by retraction of the base of the tongue is recorded. It has been stated that negroes have committed suicide by doubling back the tongue into the throat, or, as it is called, swallowing the tongue.[887] In giving anæsthetics, the subject being supine, and the head and neck somewhat flexed, the tongue, epiglottis, and soft palate may fall backward and suffocation may follow. Howard[888] states that pulling the tongue forward under such circumstances may reopen the pharynx, but will not lift the epiglottis. The thorax should be raised and head and neck extended backward. He believes that in giving anæsthetics the head should be lower than the shoulders. In order to avoid vomiting no food should be taken for some hours before the anæsthetic.
Cases are recorded of artificial teeth having fallen from the mouth into the air-passages during anæsthesia and sleep, and in epileptic and puerperal convulsions. It would appear advisable that these teeth should be worn only while eating (Case 13).
Hemorrhage from the lungs, from rupture of an aneurism or from injury of the mouth or throat, may make its way into the air-passages and cause suffocation. So also the bursting of an abscess of the tonsils or other part near the air-passages (Case 7).
Œdema of the glottis from scalding or other irritation of the fauces or glottis, or from disease of the kidneys; tumors pressing on some portion of the air-passages; rapid, profuse bronchial secretion in infants; acute double pleuritic effusion; cheesy glands ulcerating into trachea; simultaneous œdema of both lungs—all of these may cause suffocation (Cases 18 and 49). [For cases of enlarged thymus gland, see Hofmann, op. cit., pp. 587, 588.]
Paralysis of the muscles of swallowing, from diphtheria or other cause, predisposes to suffocation. Progressive asthenia in which the muscles are exhausted; injury of spinal cord or pneumogastrics; paralysis of muscles of respiration from the use of curare; the spasms of tetanus and strychnia poisoning; the entrance of air into the pleural cavities with collapse of the lungs—all tend to cause mechanical suffocation either by pressure or by paralysis (for deaths in epileptics, see Cases 1, 10, 11, 33, and 40).
It is not necessary that the air-passages should be absolutely closed to cause suffocation.
The cause of death is more likely to be pure asphyxia, because of the absence of the complicating pressure of the hand or ligature on the vessels and nerves of the neck, and of fracture of larynx or vertebræ.
Symptoms.—Foreign bodies[889] entering the trachea naturally fall toward the right bronchial tube instead of the left because of the size and position of the entrance of the right tube. If then but one tube is involved, the signs will usually be on the right side; whereas if the foreign body stop in the larynx or trachea, both sides will be affected. The latter condition is much more dangerous. The symptoms would be resonance over the lung with the respiratory murmur partly or wholly absent; less mobility; puerile breathing on the unaffected side. In either case there may at first be little disturbance, especially if the shape of the foreign body is such as not to greatly interfere with the access of air; otherwise there may be at once, and almost always will be after a time, more or less urgent dyspnœa. Diminution of the necessary oxygen may cause convulsions, apoplexy, and other brain symptoms. Acute emphysema of the portion of lung not obstructed may follow its forcible distention. The local effect of the foreign body is an irritation which causes spasm and cough. It may be carried upward by the expirations and downward again by each inspiration. Inflammation is likely to appear eventually and may involve the lung. If the obstruction is not complete there may follow periods of alternation of good and bad health, ending perhaps in recovery. The foreign body may be expelled after a greater or lesser interval. On the other hand death may result from secondary causes. In the absence of correct history the symptoms may lead to a wrong diagnosis and inappropriate treatment; as where a patient whose symptoms resulted from the presence of a piece of bone in the larynx, was treated for syphilis. A foreign body may be coughed up from the lung into the trachea and fall backward into the opposite lung.
Partial closure of the larynx, most likely caused by a flat or irregular substance, rather than globular, may cause gradual asphyxia with symptoms of apoplexy, making the diagnosis difficult.