US3074406A - Surgical sponges - Google Patents

Description

United States Patent() 3,974,496 SRGCAL SFNGES Fatti Nuineio, ighland Park, and Gordon Lindenhlad, Township, Nd., assignors to @lin Mathieson Chemical orporation, New York, NX., a corporation oi Virginia No Brewing. Filed June 16, i959, Ser. No. Silul 3 Claims. till. l--d) This invention relates to improved surgical Sponges and the preparation thereof.

The location and recovery of surgical Sponges (i.e., sterile pads of absorbent material used to absorb body iluids which tend to collect and thus interfere With the erformance of successful operative procedures) is a problem which is as old as the operative procedures themselves. The problem is made more difficult by the tendency of the Sponges to become camoul'laged through absorption o the colored body fluids thereby diminishing the usefulness of the visual faculties in detecting them. Attempts have been made to solve the problem by maintaining a careful count of the Sponges that are used and comparing it with the count of the Sponges which are discarded. 1further attempts at solution have been made by using metal-wired sponges which can be located by X-ray. Neither the tally method, nor the X-ray method has been an ideal solution since in the case of the former human fraility often leads to improper counts, and in the case of the latter, the use of X-rays results in unwanted delays towards tne completion of operative procedures While awaiting the developed X-ray pictures, and necessitates the presence in the operating room of the cumbersome and expensive X-ray equipment.

lt is the object ot this invention to overcome the deliciencies of the art by the provision of surgical Sponges having affine thereto with suilicient permanence to resist leaching by the body fluids, a non-toxic quantity of a radioactive labeling agent sufdcient to render the labeled sponge easily detectable by conventional scintillation counters.

ln accordance With the method of this invention, the labeled Sponges are prepared by contacting pieces of absorbent material of suitable size to be useful as surgical Sponges, with a radioactive labeling agent, and subjecting them to conditions of heat and pressure for a time su'icient to assure sterilization.

Unexpectedly it has been found that the single step of autoclaving the impregnated sponge until it is sterilized yields, not only a sponge Which is surgically sterile, but one which contains a labeling agent ailhred With such permanence that it remains aixed to the sponge even in the presence of body fluids in which the labeling agents per se are soluble. The sterilized labeled sponge thus prepared can be used in the manner prescribed for ordinary unlabeled surgical Sponges.

The absorbent material suitable for use herein can be any substance which is normally used as a surgical sponge. Cotton gauge pads, being readily available and highly economical, are preferred.

The labeling agents suitable for the practice of this invent-ion must contain, preferably in chemically combined form, a metallic or non-metallic radioactive isotope which is non-toxic in quantities which are suieiently radioactive lto percepti'oly register on conventional crystal scintillation counting equipment. Thus, in the proper amount, it must be able to register a count which is at least two, and optimally at least rive times the count being continually registered by the ambient radiation normally existing in the atmospheric background. Preferred isotopes are those which have a hall life greater than one Week and less than two months and emit primarily gamice .ma radiation. The isotopes may form, or be a part of, either the anion or the cation of the compound which constitutes the labeling agent. The isotope may be chemically combined as a simple ion resulting from the loss or gain of electrons, or in the form of a complex ion such as the chromate ion. Among the preferred radioactive isotopes may be mentioned inter alia: radioactive halogens such -as 1131; radioactive alkaline earth metals such as Bali0 and Ca47; radioactive alkali metals such as Rb; and radioactive heavy metals such as those of the iron period (e0. Cr51, Mnz, 21165 and Fe59); and those of the silver period (eg. Ag105, Agl6 and Cd115).

The labeling agent is most conveniently applied to the surgical sponge in the form of a dilute solution of the radioactive chemical compound in a liquid medium. The liquid medium may be chosen from a Wide range of organic solvents and inorganic solvent which will dissolve the radioactive compound to be used as the labeling agent. useful solvent it is preferred as the liquid medium for Water soluble labeling agents. To prepare the solution it is only necessary to dissolve the radioactive material in the Water. This may in most cases be accomplished at room temperatures, but may be hastened in others by the application of heat. Among the labeling agents Which may be formed with the foregoing radioactive isotopes there may be named *sodium chromate (it indicates the radioactive moiety), *calcium iodide, *barium carbonate, zinc "chloride, ferrous ilsulfate, ferric itchloride, cadmium *sulfate and silver *nitrate The proper concentration of the radioactive material in the solution will depend on the amount of solution to be used in treating each sponge. Suliicient solution should be used for each sponge to assure that the sponge will be suiiiciently radioactive to register a count of at least twice, and optimally etween live and ten times the background count on a crystal scintillation counter.

In order to prepare the labeled surgical Sponges of this invention a conventional sponge is treated with a quantity of a solution of the radioactive labeling agent, as defined above. The labeling agent is then aixed to the sponge by subjecting it to heat and/ or pressure (eg. autoclaving) for a time sufficient to at least sterilize the sponge. Conventional hospital autoclaving equipment is suitable for the performance of this step. Suitable results are obtained by heating the sponge at 250 F. and l5 p.s.i. for a period of l5 minutes. rl`e1riperature, pressure and length of heating step may be varied so long as the selected conditions will yield properly sterilized Sponges.

The Sponges thus produced are used as the conventional unlabeled Sponges. They should be used Within a short period following preparation in order to insure that decay of the labeling agent does not proceed to the point at Which the labeled Sponges are not suticiently radioactive to energize the conventional crystal scintillation counting equipment which is to be used to locate the sponge.

Aft-er use, the Sponges may be discarded through the usual radioactive Waste disposal facilities.

The following example is presented to more fully illustrate the invention.

EXAMPLE A. Preparation of Sodium Chromate Solution A glass vessel containing dilute solution of chromic chloride (l0 ml.) having a speciiic activity of l0 millicuries/mg. is immersed in an ice-salt water bath and chilled to below 4 C. 2 N. sodium hydroxide is added to the chilled solution dropwise, with stirring until a light blue opalescent precipitate appears. The dropwise Since Water is the most readily available yand addition is continued until the precipitate dissolves. Hydrogen peroxide (30%) is added dropwise until the light blue-green color changes .to yellow and the solution is removed from the Water bath and boiled to remove the B. Preparation of Labeled Surgical Sponges A( conventional cotton gauze surgical sponge measuring Z n 2" is treated with 0.1 ml.y of the solution prepared in step A. The treated sponge Iis Wrapped in absorbent paper and placed in an autoclave which is adjust'edY to maintain a pressure of 15 p.s.i. at `a temperature of 250 F. The spongeY is removed from the autoclave and tested for specific activity. It shows a radio# activity'of 1.2 microcuries.

In order to show the usefulness of the Sponges of this invention a sponge prepared as in step B was implanted in a large dog. The sponge exhibited sucient radioactivity to be easily detectable by a conventional crystal scintillation counter. lThe urine of the dog tested negative 24 hours for radioactive material, and gross lscintilla- 'tion scanningv of` the animal .indicated no translocation of radioactivity throughout the animal. The tests show that the radioactive moiety had been permanently fixed to the sponge by autoclaving.

Eollov'ving the exemplied procedure, surgical sponges l. A process of preparing a surgical sponge having a radioactive labeling agent permanently affixed thereto and impregnated thereon, which comprises treating an absorbent material wvith a solution of a radioactive labeling `agent until a non-toxic quantity of said agent is absorbed and then heating the absorbent material for a time and under conditions Sucient to permanently aix the radioactive labeling agent to the absorbent material'and to assure sterilization,

2. A process'of aixing a radioactive labeling Yagent to a `surgical sponge, vwhich comprises treating a surgical cotton sponge with a solution of a radioactive labeling agent until 4a non-toxic quantity of said agent is absorbed on said sponge and then autoclaving the sponge for a time suiicient to permanently Aaiiix the radioactive labeling agent to the sponge and to assure sterilization of the sponge.

'3. The process of claim 2 in which the labeling agent is sodium radioactive chromate.

References Cited in the le of this patentV UNITED STATES PATENTS

Claims (1)

1. A PROCESS OF PREPARING A SURGICAL SPONGE HAVING A RADIACTIVE LABELING AGENT PERMANENTLY AFFIXED THERETO AND IMPREGATED THEREON, WHICH COMPRISES TREATING AN ABSORBENT MATERIAL WITH A SOLITION OF A RADIOACTIVE LABELING AGENT UNTIL A NON-TOXIC QUANTITY OF SAID AGENT IS ABSORBED AND THEN HEATING THE ABSORBENY MATERIAL FOR A TIME AND UNDER CONDITIONS SUFFICIENT TO PERMANENTLY AFFIX THE RADIOACTIVE LABELING AGENT TO THE ABSORBENT MATERIAL AND TO ASSURE STERILIZATION.