Monthly Archives: September 2013

1890s, Drawing, MIP/MEP

Marchal’s Pneumatometer, 1895

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Marchals_Pneumatometer_1895

From Physical and Natural Therapeutics by Georges Hayem, 1895, page 21.

“Marchal’s Pneumatometer consists essentially of a manometric tube, representing almost a complete circle, and communicating at its upper portion with a mouthpiece, from or into which inspiration or expiration is made according as the force of one or the other is to be measured. Index needles serve to mark the diminuation and the increase in pressure (fig 3.).

“If the inspiratory force is to be determined, the needle is placed on the side marked inspiration, and with it also one of the maximal needles. Then, having made a strong expiration, the person applies the lips hermetically against the mouthpiece and takes the deepest inspiration possible. The index needle is displaced, carrying the maximal needle with it; the latter remains at the extreme point, but the former quickly rebounds. The number of degrees indicated by the maximal needle corresponds to the pressure in centimeters of mercury.

“To measure expiration, the stopcocks are reversed, and the needle, carrying the maximal needle with it is placed on the corresponding side. The subject after taking the strongest possible inspiration expires forcibly, and the second maximal needle indicates the result of the effort.

“As a rule the inspiratory effort is less powerful and the expiratory; according to Marchal the ratio is 2 to 3.

“Moreover the result of the effort is not necessarily proportionate to the vital capacity, for the muscles of respiration vigorous in one possessing a relatively small vital capacity, and vice versa.”

1860s, Drawing, Spirometer

Hydro-Spirometer, 1861

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Hydro-Spirometer_1861

From the Hydro-spirometer, by T. Lewis MD., British Medical Journal, Volume 2, 1861, page 255.

“The new form of spirometer I am about to bring under your notice, is constructed on the principal of displacing a certain quantity of water by an extreme effort of expiration from a graduated glass jar. The jar is graduated in cubic inches, the enumeration proceeding from above downwards, and the results of the experiment is read off the graduated scale.

“Description of the instrument. The jar is about sixteen inches in height and five and a half inches in diameter. It is closed at the top by a metallic cap, which is perforated by three holes, into which are inserted corresponding tubes, as will be seen in the diagram.

“While in operation, the instrument is laid almost horizontally on the table, having been previously filled with water up to the level of the mark which indicates the commencement of the scale. The glass mouthpiece at the extremity of the elastic tubing is then placed in the mouth, and, after an extreme inspiration, the fullest expiration is made. There is no necessity for any precautions at the close of the expiratory effort. After the effort, the instrument is replaced in the erect position, in order to read off the amount of air introduced into the jar. There is no necessity for any correction on account of temperature, as it assumed that the air proceeding from the lungs is nearly always the same temperature.”