While it is the rule that the tube is no longer necessary after the fourth or fifth day and frequently not after the second or third, yet it sometimes occurs that it cannot be dispensed with for two, three, or six weeks, or even longer. After its removal the dyspncea returns, sometimes immediately, and sometimes after a few hours, occasionally after one or two days have passed.
It is always well to remain with the patient an hour after the removal of the tube or be within ready call in order to replace the tube in case of emergency. Cases of sudden death have occurred from returning dyspncea after the opera tion has left the patient in fancied se curity. As a rule, the dyspncea returns slowly; so that it is several hours before the patient is in an alarming condition. Occasionally it returns suddenly and al most immediately after the removal of the tube.
Prolonged Use of Tube. — A number of causes have been enumerated as rendering necessary the long-continued use of the tube. Principal among them may be mentioned the formation of diphtheritic exudate or its long persis tence in the larynx and trachea; oedema of the tissues; ulceration of the cricoid cartilage and consequent collapse of the thyroid cartilage; cicatricial contrac tions and exuberant granulations follow ing ulcerations and abduction paralysis.
Pressure-sores produced by the pro longed contact of the tube with the air passage were found in post-mortem ex amination in 156 cases, or 13 per cent. of the 1203 submitted to intubation in the Children's Hospital at Budapest. Sixteen out of the 499 cases which re covered showed symptoms of pressure sores, and were therefore subjected to secondary tracheotomy. The sores were located on the anterior wall, and in order of frequency in the trachea, thy roid, and cricoid cartilages. They varied in depth from superficial ulcers to those exposing the cartilages and attended with perforation. Coughing and blood stained expectoration. The severe cases are apt to result in cieatricial stenosis of the larynx. V. Bokay (Centralb. f. Chin, May 11, 1901).
In some of these the lesions are due to a too tightly fitting tube, to leaving the tube in too long, to poorly-constructed instruments, and some to injuries result ing from unskillful operations.
With the use of antitoxin, which en ables the patient to dispense with the tube at an earlier day, and greater skill acquired in performing the operation, these conditions will less frequently arise.
An important point to emphasize is that when the operator appreciates the fact that a tube is too large, as indicated by the force required to press it down into position, he should at once remove it and use a smaller one. The unduly large one will not only cause ulceration or paralysis from undue pressure, but, in case of obstruction below the tube, also Dive rise to exfoliation of membrane. There will, furthermore, be great danger of sudden suffocation from the inability of the patient to expel the tube.
Erosion of the mucous membrane and exposure of the cartilages observed at the autopsy in 4 of 42 eases. Ganghofner (Jahrb. f. Kinderh. u. phys. Erzie., Nov. 30, '90).
Case of sudden death, on reinsertion of tube, from tracheal cast pushed down by tube, after removal on seventh day. Evans (Archives of Pediatrics, Mar., '95).
[Death, in such cases, may be due to (1) asphyxia; (2) pushing down of membrane; (3) making false passage, beginning in ventricle. The latter is more liable to occur, at the end of the week, on reintroduction, through pre vious obliteration of the ventricle by pseudomembrane, etc. Practice in ca daver, where the ventricles are avoided with difficulty, is recommended. It can only occur when the patient's head is thrown too far back, bringing the lower end of the tube against the anterior laryngeal wall. JOSEPH O'DWYER, Assoc. Ed., Annual, '96.] Decreasing length of tube a means of obviating obstruction accidents. Bayeux (La Med. Moderne, May 25, '95).
[Length is as important as breadth, thickness, or calibre. The present length was adopted, not after experiments on cadaver, but on the living, steps be ing suggested by post-mortem findings. Diphtheria is rarely confined to the larynx when the time for intubation or tracheotomy is reached. Tracheal de tached membrane is the greatest danger of intubation; the expiration is suddenly arrested by closure of lower end of tube. Hence the length of the latter. Bayeux's claim for short tubes is theoretical, ex cept in statement that they can be expelled by pressure from outside: a method frequently employed in the United States. Cheatham claims to have been first in its adoption. JOSEPH O'DWYER, Assoc. Ed., Annual, '96.] Case in which use of catgut led to fatal asphyxia and to belief that tube had fallen into trachea, the catgut having absorbed moisture and appearing as soft tissue to finger. Delvincourt (Union M6d. du Nord-est, June 30, '95).