As to the entrance of air into the retention-cavity, later experience has shown us that its danger depends upon whether it has been disinfected or not; the contact of even hospital air, which has been made aseptic by means of a carbolic or salicylic spray, being innocuous. Nevertheless, it is advisable in places where an efficient drainage is difficult to obtain, to prevent the entrance of air as much as possible. M. Sims, Schatz, and Hegar have studied the conditions upon which depend the entrance of air. Schatz has especially made it clear that the pressure-relations within the pelvis, whether the patient be in the knee-elbow, in Sims's, or in any other position, is changed as soon as any organs which occupy the true pelvis are lifted out of it. Since the bony walls will not give way, as soon as the pressure sinks below that of the atmosphere air will enter if allowed to. When the elevated and dilated organs, the uterus and the vagina, cannot sink down en masse after evacuation, so as to prevent a negative pressure in the pelvis, air will rush in through the gaping wound.
This may occur by any operation, but is especially liable to happen when we use the trocar and canula. In fact the change in shape and position of the emptying sac is often an insufficient one; and this on account not only of the pseudo-membranous fixation of the uterus and tubes, but perhaps oftener because of the hypertrophy and dilatation of the collum uteri, and that portion of the vagina which lies above the atresia.
It is, therefore, advisable not to elevate the patient's pelvis too much; and in narrow, septum-like atresias not to keep the orifice open with the knife, until the pressure of the fluid has sunken so that it ceases to flow. We cannot make use of the ordinary measures to prevent the entrance of air when puncturing, because we do not employ the simple puncture with the trocar. When it is absolutely necessary, as in broad atresias, to leave the canula lot aitu, we must use antiseptic injections and see that there is a free outflow; for the entrance of air and the decomposition of the secre tion which is left behind is unavoidable. At least we should attempt to disinfect the entering air as much as possible, by packing the end of the canals in disinfectant absorbent cotton or gauze; or, if short canulce which do not project from the vagina are employed, closing the external genitals with an antiseptic pad. We have. often used compresses soaked in dilute chlorine water for this purpose.
At least as important as the above-mentioned precautions during the operation, is the prevention of the entrance of air after the operation.
We must especially avoid any manipulations which would cause the vaginal canal to gape, such as digital or specular explorations, the introduction of sounds, etc. Attempts to do these things have caused the ill-success of operations which had otherwise turned out well, and in cases in which all danger was supposed to be over. I called attention to this point some time ago,' and Elischer2 has since then published certain cases of Spiegel berg which show its importance.
Since the entering air does most harm when abundant stagnating secre tion is present, it is extremely desirable to obtain as thorough an outflow of the contents of the tumor as is possible. For this reason I must sus tain Puech in his criticism of the process recommended by Scanzoni ' and Baker-Brown, to puncture through the rectum. In favorable cases it palliates the trouble for a time; but our experience is hardly sufficient as yet upon this point.
It is difficult to say whether Simon's idea to open the sac from the blad der can be successfully accomplished. IV. Krause in his dissertation (Marburg, 1872) recommends it. It would possess the advantage that 710 foul gases would enter the sac, and the menstrual blood could flow off perfectly well through the bladder, if the fistula is only large enough.
We see this in successful c,ases of vaginal obliteration. But the same ob jection which has recently led many surgeons to reject Simon's transverse obliteration would apply here. It would occasionally lead to cystitis and pylonephritis, and sometimes give rise to vesical concrements.
It has been recommended for the purpose of avoiding septic infection to wash out the retention-sac, and thus get rid of all the blood immedi ately after the operation. Emmet is the most prominent advocate of this proceeding, and layA especial stress upon the use of very hot water for the purpose. Others use disinfecting fluids.
In our experience the washing out of the sac is only necessary when the evacuated fluid is already in a state of decomposition. Under ordinary circumstances antiseptic injections are only necessary later, when the pres sure in the sac has so far sunk that no more blood flows out, and the vaginal secretions easily undergo decomposition, or when air has entered into the sac through the canula. The indications for injections are rarely present before the second or third day. Not only is it not necessary to use injections immediately after each operation; but to do 6o would inter fere with the measures which have been recommended to prevent rupture of a hiematosalpinx. If there is no hiematosalpinx, irrigation will cer tainly do no harm.