The administration of nitrous oxide and oxygen for dental operations / by Frederick W. Hewitt.

  • Hewitt, Frederic W. (Frederic William), Sir, 1857-1916.
Date:
1901
Catalogue details

Licence: Public Domain Mark

Credit: The administration of nitrous oxide and oxygen for dental operations / by Frederick W. Hewitt. Source: Wellcome Collection.

Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.

    79/132 (page 55)
    be seen on raising the upper lids. The pupils are generally of medium size or moderately dilated. There is a striking contrast between the closed lids of this form of anaesthesia and the open and turned-up eyes so often seen in ordinary nitrous oxide narcosis. Amongst the numerous points to which attention must be paid in conducting the ad- ministration, there is one which is of consider- able importance. It is that the anaesthetist must allow for what may be termed the delayed effects of admitting more or less oxygen. For example, let us suppose that slight phonation occurs when the indicator points to 7. By turning it to 3 or 4 the phonation will in the course of a few moments subside. But if the indicator be kept at 3 or 4 till the patient is perfectly quiet, the anaesthetist will probably have gone too far in the asphyxial direction. He should turn to 3 or 4 for a few breaths only and return to 5, 6 or 7 before the phonation has ceased. In other words, he must bear in mind that a little interval must necessarily elapse before the effects of an increase or decrease in oxygen admission will become manifest. As regards the length of inhalation re- quisite for the production of the typical pheno- mena of anaesthesia, I have found that it is, on