Testing For Electric Defects
Categories: ACQUIRING SKILL
Sources: A Manual Of Peroral Endoscopy And Laryngeal Surgery
These tests should be made
beforehand; not when about to commence introduction.
If the first lamp lights up properly, use it with its light-carrier to
test out the other cords.
If the lamp lights up, but flickers, locate the trouble before
attempting to do an endoscopy. If shaking the carrier cord-terminal
produces flickering there may be a film of corrosion on the central
t of the light carrier that goes into the carrier cord-terminal.
If the lamp fails to show a light, the trouble may be in one of five
places which should be tested for in the following order and manner.
1. The lamp may not be firmly screwed into the light-carrier.
Withdraw the light-carrier and try screwing it in, though not too
strongly, lest the central wire terminal in the lamp be bent over.
2. The light-carrier may be defective.
3. The cord may be defective or its terminals not tight in the
binding posts. If screwing down the thumb nuts does not produce a
light, test the light-carrier with lamp on the other cords. Reserve
cords in each pair of binding posts are for use instead of the
defective cords. The two sets of cords from one pair of binding posts
should not be used simultaneously.
4. The lamp may be defective. Try another lamp.
5. The battery may be defective. Take a cord and light-carrier with
lamp that lights up, detaching the cord-terminals at the binding
posts, and attach the terminals to the binding posts of the battery to
Efficient use of forceps requires previous practice in handling of
the forceps until it has become as natural and free from thought as
the use of knife and fork. Indeed the coordinate use of the
bronchoscopic tube-mouth and the forceps very much resembles the use
of knife and fork. Yet only too often a practitioner will telegraph
for a bronchoscope and forceps, and without any practice start in to
remove an entangled or impacted foreign body from the tiny bronchi of
a child. Failure and mortality are almost inevitable. A few hundred
hours spent in working out, on a bit of rubber tubing, the various
mechanical problems given in the section on that subject will save
lives and render easily successful many removals that would otherwise
It is often difficult for the beginner to judge the distance the
forceps have been inserted into the tube. This difficulty is readily
solved if upon inserting the forceps slowly into the tube, he observes
that as the blades pass the light they become brightly illuminated. By
this light reflex it is known, therefore, that the forceps blades
are at the tube-mouth, and distance from this point can be readily
gauged. Excellent practice may be had by picking up through the
bronchoscope or esophagoscope black threads from a white background,
then white threads from a black background, and finally white threads
on a white background and black threads on a black background. This
should be done first with the 9 mm. bronchoscope. It is to be
remembered that the majority of foreign body accidents occur in
children, with whom small tubes must be used; therefore, practice
work, after say the first 100 hours, should be done with the 5 mm.
bronchoscope and corresponding forceps rather than adult size tubes,
so that the operator will be accustomed to work through a small
calibre tube when the actual case presents itself.