Avaliação da esterilidade do instrumental laparoscópico de uso único reprocessado 1

O presente estudo, experimental, laboratorial e comparativo, teve como objetivo avaliar a eficácia da esterilidade dos instrumentos laparoscópicos de uso único (ILUU): grasper, dissector, tesoura, agulha de Veress e sistema de sonda de eletrocirurgia, após contaminação desafio com esporos bacterianos e sangue de carneiro, e comparar os resultados dos testes de esterilidade com aqueles dos instrumentos equivalentes “permanentes”. Para limpeza, utilizouse lavadora ultrassônica com jato pulsátil e detergente enzimático, limpeza manual, água sob pressão e enxágue. Os ILUUs foram esterilizados por óxido de etileno, os instrumentos “permanentes” em autoclave. Os testes de esterilidade acusaram resultados 100% negativos para a recuperação dos micro-organismos contaminantes, nos dois grupos. Concluiu-se que, em relação ao alcance da esterilidade, é possível reprocessar ILUU.


Introduction
Single-use devices (SUD) have been used for more than half a century in healthcare.Initially, they were manufactured with the aim of solving problems faced by health professionals, resulting from overload of work in Materials and Sterilization Centers (MSC), as well as the advantage of ensuring the availability and quality of the material, due to it always being of first use.However, some of these devices have a very high cost to be discarded after one use, due to the advanced technology incorporated into their manufacture: electronic circuits, membrane technology, optical components and highcost miniaturized components.As a strategy to circumvent the problem, the health facilities began to reuse them (1) .
Single-use devices are generally produced from thermo-sensitive and less noble raw materials, such as plastics and elastomers.Most of these cannot be dismantled and have internal spaces with difficult access for cleaning.This situation generates doubts about the permanence of residual organic matter in the material and the safety of the sterilization process.
evidence, but on conflicts of interests, that resulted from public consultations (Nº.98 on 06/12/2001 and Nº. 17 on 19/03/2004) and also a public hearing on 03/06/2005.Thus, single-use laparoscopic instruments (SULIs) were included in the list of materials prohibited to be reused, although other SUDs, no less complex, such as myocardial stabilizers, angioplasty catheters, vitrectomy probes, to name a few, were not included (2) .
Considering that the reuse of SULIs occurred with relative intensity in various regions of Brazil before its prohibition, the realization of this research is justified, as a way to evaluate the risk of hospital cross-infection of patients who undergo procedures with reused SULIs (grasper, dissector, scissors, Veress needle and electrosurgical probe system).It is also believed that this study will help to elucidate the safety aspects of the reprocessing of devices of complex conformation.
In reviewing the literature only one study (3) was found that aimed to evaluate the achievement of sterilization of laparoscopic scissors -one of the devices studied in this investigation.In that study, the sterilization of laparoscopic scissors was not achieved.
However, this result is inconsistent with that achieved throughout the years of utilization of reused SULIs.It is understood, therefore, that there is a need for more research on this topic.Based on this reasoning, it was concluded that the issue remains controversial.
Starting from the premise that the proper and careful cleaning of the devices is the main determinant of the result of effective sterilization (4)(5) , especially when the low temperature method is employed, the initial hypothesis of this study was that, even facing the contamination-challenge of samples with 1 million sporulated bacteria, added to blood, sterilization may be achieved when the appropriate technology for the process is applied, especially regarding cleaning.

Aims
To evaluate the efficacy of the sterilization of singleuse laparoscopic instruments used in video-surgicallaparoscopy after the contamination-challenge.
To compare the results of the sterility tests with those of similar reusable instruments.

Materials and Method
This was an experimental, comparative, laboratory study, in which all variables could be controlled.The choice of this micro-organism was justified by the fact that this is the standard biological indicator for monitoring sterilization cycles by means of ethylene oxide (EtO), the method was chosen for the experiments due to its high diffusibility and compatibility with the thermo-sensitive materials (6) .
The reusable instruments underwent the same process of contamination, except with Geobacillus stearothermophilus -ATCC 7953, due to this being the standard microorganism in the biological indicators to Lopes CLBC, Graziano KU, Pinto TJA.
monitor the steam autoclave sterilization cycles, the type of sterilization recommended for stainless steel devices (7) .
Next, the dried, contaminated instruments were immersed in drinking tap water for approximately 30 minutes in order to moisten them.In sequence, all devices were subjected to enzymatic detergent cleaning, first in an ultrasonic cleaner with pulsatile water jet; after washing this was complemented with manual cleaning, as required by the test-protocol described below, prepared for reprocessing, both for the singleuse and reusable devices.With the SUDs, the tests were destructive.Under laminar flow, each material was broken using sterile pliers so that the samples could be completely immersed in the culture medium.The instruments of the comparison group were dismantled and also immersed directly in the culture medium.

Results
The results of the microbiological cultures of the video-surgical-laparoscopic devices marketed as singleuse and the reusable devices, after the contaminationchallenge, cleaning and sterilization are presented in

Discussion
This study provides scientific evidence of the technical possibility to sterilize devices marketed as single-use for video-surgical-laparoscopy, produced from plastics and elastomers, which cannot be dismantled and are of a complex conformation, which are: grasper, dissector, scissors, Veress needle and electrosurgical probe system.
Studies with similar objectives to those of this research -verifying the safety of reprocessing SUDs regarding the sterility implications -were developed by some authors (2,(8)(9)(10) and yielded different results: In 2002, researchers (3)  The same similarity between the single use and the reusable devices is found in the single-use pen handle scalpel and its reusable equivalent.The comparison between the two models in relation to the success of cleaning and sterilization was also the object of research.The results showed no significant difference in the degree of sterilization between them (11) .A paradox regarding the Veress needles is that the single-use needle couples with great firmness to the terminal of the ultrasonic washer with pulsatile water jet, which does not happen with the reusable ones.Accordingly, the flow pressure in the lumen of the needle is less, due to the "leakage" of water flow through the lateral orifices due to disassembly of the device itself.
The analysis of the negative results of the microorganism CFU count for the material in the experimental group and for the reusable comparative group, after the contamination-challenge with similar outcomes, demonstrates the need to review the concept of "single use" devices of high cost, since there is evidence that it was possible to sterilize the devices even with the Lopes CLBC, Graziano KU, Pinto TJA.
contamination-challenge, which is unlikely to be a real scenario in care practice.In the case of the pens handle scalpels, the best performance regarding efficacy of sterilization was achieved when the automated cleaning technique was applied (11) .
A study (10) performed with single-use reprocessed trocars after the first use in patients undergoing elective laparoscopic cholecystectomy, found results of achieving sterility in 100% of the sample, after cleaning and sterilization with three different methods at low temperatures (ethylene oxide, low temperature steam and formaldehyde, and hydrogen peroxide plasma).
The low impact of the results of this study was due to sporulated micro-organisms not having been used together with organic matter, which constitutes a real challenge for reprocessing.In the study in question, only 46.5% of the sample devices showed the presence of micro-organisms before cleaning, which represents a low challenge considering the aim of the research.
In 2009, a study (12) that evaluated the microbial load on instruments used in clean orthopedic surgery, found a maximum of 10 2 CFU of the genus Bacillus, per instrument, this micro-organism is able to sporulate under adverse environmental conditions.In the present study, the sporulated microbial challenge was approximately 10 6 CFU/instrument.
The granting of the stamp 'single-use' is strongly supported by the fact that the single-use material is complex and not able to be dismantled for cleaning, along with their non-noble raw materials (plastics and elastomers) that cannot resist aggressive and repetitive methods of cleaning and sterilization.Comparing the reusable video-surgical-laparoscopic forceps with the single-use ones, it was noted that, in these, there are virtually no empty internal spaces in the structure, and they could even be considered a 'solid material', which may explain the success in achieving their cleaning and sterilization in this study.It is noteworthy that the results of the present study were obtained after contaminationchallenge (10 6 CFU/ml of sporulated microorganisms diluted in blood) which supports the findings of the technical possibility of sterilizing SUDs.The great contribution made by this research is the clarification that the reuse of single-use devices may be possible if there is quality in the work process for their processing.
Other studies have been published with outcomes similar to this study regarding the elimination of microorganisms inoculated as a challenge.In 2003, a study (8) compared manual and automated cleaning for the  Another study (9) evaluated the efficacy of the A relevant concern, regarding the reprocessing of devices, is the biofilms that may be present mainly in areas of difficult access for cleaning.Biofilms are "structured communities of cells of microorganisms, embedded in a polymeric matrix and adherent -exopolysaccharides -to an inert or living surface" (13) .It is known that when it is not possible to completely dismantle a material for Rev. Latino-Am.Enfermagem 2011 Mar-Apr;19(2):370-7.
total cleaning it is more susceptible to the presence of biofilms and that bacteria and fungi can protect themselves from external factors and multiply in the biofilms representing a potential risk of cross infection.
Biofilm formation is theoretically feasible on material with surfaces which cannot be completely scrubbed in each cleaning process, as in the present investigation.
This reinforces the categorization of these devices as 'limited use'.Considering that the financial factor is the main determinant for the reuse of expensive SUDs, the number of reuses should be proportional directed by the unit costs of these.One study (14) found that 10 reuses of video-surgical-laparoscopic accessories, for the study site, was compatible with the high unit costs of these.
There is consensus that the efficacy of the sterilization should be explored through the destruction of bacterial spores, such as the biological indicators that monitor the sterilization cycles in the routine of a MSC.However, as future research, it is worth exploring the issue "microbiological safety in the reuse of SUDs" through the contamination-challenge with biofilm forming microorganisms such as P. aeruginosa, considering that SUDs cannot be dismantled, as a rule, to be cleaned, which, in theory, favors the formation of biofilms.when compared to the new (15) .Thus, in our context, it can be affirmed that the validation of the reuse of the video-surgical-laparoscopic accessories as to their functionality has been empirically approved by the surgeons, direct users of these devices.Prior to the explicit prohibition by legislation of the National Health Surveillance Agency (ANVISA) (2) , the practice of reuse of the devices investigated in this study was frequent within the national reality, and many surgeons claimed to prefer the reprocessed single-use material rather than the reusable ones, which contributes to reinforce the practice of reuse.Thus, it is possible to affirm that care practice has already tested and approved the functionality of these reprocessed single-use devices, illegally and without scientific justification.
This study was limited to the investigation of the achievement of sterility.However, other potential hazards may be present in the material, even when sterilized: the presence of biofilms, endotoxins, and residues of blood proteins and of toxic products used in the reprocessing, among others.These risks deserve further studies to effectively exempt the practice of the reuse of these devices from any risk and reverse, if applicable, the registration of these devices to limited reuse rather than single-use.

Conclusion
This study confirmed the initial research hypothesis: there was the achievement of sterilization in single-use devices used in video-surgical-laparoscopy (grasper, dissector, scissors, Veress needle and electrosurgical probe system) as well as the equivalent reusable devices, faced with the contamination-challenge with sporulated micro-organisms.
The research steps were performed in the following laboratories: Microbiological Testing Laboratory of the Department of Medical-Surgical Nursing, School of Nursing, University of São Paulo (USP), the laboratory of the Control of Medicines, Cosmetics, Household Cleaning Products, related products and their raw materials (CONFAR) of the Pharmacy Department, Faculty of Pharmaceutical Sciences of USP, and the Materials and Sterilization Central of the University Hospital of USP.For this study 120 devices marketed as single-use were used in the experimental group: 25 for validation tests of the method and 95 for the data collection itself.A total of 35 "reusable" instruments were employed as the comparison group throughout the different phases of the research.The sample size in the experimental group had a power of 99.9%.The SUDs used in this study were purchased from the company Ethicon ® Endo-Surgery, Inc., the packaging of which contained the following identification: Grasper forceps: 1 ENDOPATH -5 mm Grasper with Ratchet Handle -lot V42R89, 2009-08, ref 5DCG; Scissors: 1 ENDOPATH -5 mm Curved Scissors with Monopolar Cautery -lot R4RC42, 2007-01, ref 5 DCS; Dissector forceps: 1 ENDOPATH -5 mm Curved Dissector with Monopolar Cautery -lot V42E5K, 2009-07, ref 5DCD; aspirator/irrigator: 1 ENDOPATH -Electrosurgery Probe Plus II -lot V41H8K, 2009-05, ref EPH01-Pistol Foot Control; stem/electrocautery: 1 ENDOPATH -Electrosurgery Probe Plus II -lot R4TH60, 2007-06, ref EPS03 -5 mm Right; Veress needle: 1 ENDOPATH -Ultra Veress Insuflation Needle with Luer Lock Connector -lot X43W1L, 2009-11, ref UV 120 -120 mm Ultra Veress.The SUDs were intentionally contaminated with a suspension of approximately 10 6 CFU (colony forming units)/ml of spores of Bacillus atrophaeus var.niger (American Type Culture Collection -ATCC 9372) quantified, standardized and diluted in sterile defibrinated sheep blood.The contaminant inoculum was injected into the existing internal spaces of the devices.Following this the instruments were left for 80 minutes on a lined surface and covered with impermeable sterile drapes, maintaining contact with the contaminant inoculum.
The test-protocol steps were: dismantling of the reusable laparoscopic forceps; wetting of the material by immersion in tap water for 30 minutes, immersion of the parts in a solution of enzymatic detergent * as directed by the manufacturer, washing of the instruments in an ultrasonic washer with pulsatile water jet specific for the cleaning of cannulas and instruments (manufactured by H. Stratnner ® ); additional manual cleaning of each piece with 2 mm diameter brushes (internal washing of the cannula of the Veress needle, stem and handle of the Electrosurgical Probe System), and delicate brushes for washing the serrations of the active part of the forceps; rack and pinion, handles and other niches and recesses of all the pieces; rinsing of the material with the aid of a high pressure water gun, directed into the internal structure of the instrument; final rinse with sterile distilled water; support of the devices in baskets lined with white drapes for a few minutes to facilitate drying and inspection for blood residue; dried with compressed air and soft medical compresses; rigorous inspection for cleanliness and integrity of devices with the aid of an image intensifier lens with focusing light; reassembly of the "reusable" forceps; individual packaging of the devices in a double-pack of surgical grade paper, placing inside the package a multi-parameter chemical integrator (class 5); sterilization of SUDs by ethylene oxide gas, and autoclave with saturated steam under pressure with pre-vacuum for the reusable instruments; forwarding of sterile samples for the sterility test.* Basic composition of the enzymatic detergent used in the experiments: amylase, protease, lipase and carbohydrase enzymes, nonionic surfactants and isopropyl alcohol It should be noted that, prior to the experiments, all the microbiological analytical methodology was validated by the technical team of the CONFAR laboratory of the Faculty of Pharmaceutical Sciences of USP, using the following phases: (PHASE 1) samples of each of the device types, both single-use and reusable, were subjected to the counting of CFU per unit of material (CFU/material) after microbial contamination, after the cleaning procedure and before sterilization (PHASE 2).In both steps the recovery of contaminants was confirmed, which attested to the adherence of the inoculum to the instrument, and the consequent challenge to the sterilization phase, giving continuity to the experiments.Such validation of the method constituted a positive control and aimed to ensure the presence of the test micro-organisms in the devices in order to challenge the sterilization.The sterility tests consisted of experiments to verify the recovery of the test micro-organisms in standard culture medium, in which they had previously proliferated.The contaminated devices, after cleaning and sterilization, were cultivated directly in soybeancasein culture medium, considered suitable for the recovery of a possible test micro-organism surviving the methods of reprocessing.The incubation period was 14 days, with daily readings of turbidity of the culture medium, with Bacillus atrophaeus incubated at 37 °C and Geobacillus stearothermophilus at 56 °C.
carried out sterility tests of laparoscopic scissors and scalpels previously contaminated with spores of Bacillus atrophaeus -ATCC 9372, subjected to cleaning and then EtO sterilization and did not achieve success.These results contradict the result of this research, which showed the elimination of all of the same sporulated micro-organisms, after cleaning and sterilization in EtO.The analysis of the methodological procedures employed by the authors of the study allowed the sterilization failure to be assigned to the fact that the devices had not been cleaned using the appropriate technological resources, since the researchers chose to wash them in a thermal washer/disinfector (pressurized water jets), this equipment is suitable for washing devices of a simple conformation, because its power of removal of dirt is less than the cleaning methods employed in this research.The cavitation action of the ultrasonic washer for cleaning devices with narrow lumen and complex conformations, associated with pulsatile water jet washing is, theoretically, a resource of greater cleaning power.There is not, in the cited work, reference to the manual cleaning that, with this category of devices, should complement or precede automated cleaning.Thus, it can be inferred that the fact of not having achieved sterilization is attributed to cleaning inefficiency, corroborating the premise that the cleaning is the core of reprocessing.Another factor that may have led to the opposite outcome in the study reviewed was that the devices had been exposed to half the time of EtO sterilization practiced in the care context and recommended in the literature.This decision to impute a greater challenge to the experiments was based on the ISO 14937 standard, which indicates an additional challenge for validation testing of sterilization.The reusable instruments for video-surgicallaparoscopy are extremely difficult to clean, since they present recesses and spaces that allow the accumulation of organic matter.In the present study, even with careful practices for dirt removal, one pair of reusable Stors ® forceps and two reusable Edlo ® vacuum/irrigators remained with residues of blood, discovered at the time of drying of the devices with pressurized air and during the visual inspection.It was noted that the reusable Veress needles were as vulnerable to the retention of organic matter as the single use ones.It was observed that the reusable needle could be dismantled into 04 parts, enabling better access for cleaning the cannula, however, the metal used in the manufacture of the cannula prevents viewing of the internal part of the lumen to check the cleaning.In the equivalent single-use needle, there is no possibility of dismantling the cannula, but this is totally transparent and allows a full view of any residual organic matter after internal cleansing by sonication.The longest part of the needle itself, which penetrates the tissues of the patient, is identical in both types; neither of which allow the viewing of the internal space or access of appliances for the cleaning of the lumen, the cleaning only being possible with an ultrasonic washer with pulsatile water jet.
and hemoglobin in order to evaluate the efficacy of the cleaning and presence of endotoxins, achieving superior results for the devices submitted to the automated cleaning by ultrasonic washer with backflow when compared to manual cleaning.In the study for evaluation of sterilization through EtO, the results have shown the total elimination of test micro-organisms.
cleaning and sterilization of cardiovascular angiographic catheters after clinical use and artificially contaminated.The single-use catheters were subjected to intentional contamination with Artificial Test Soil (ATS) plus Enterococcus faecalis and Pseudomonas aeruginosa.The results of microbiological testing, after 100% EtO sterilization of the catheters, were negative for all sample units.Concerning the results of tests for the presence of endotoxins, the study showed that the most indicated method was to flush the catheters with sterilized water treated by reverse osmosis after cleaning, due to it achieving total absence of endotoxins in the devices tested.The efficacy of the cleaning was assessed by direct and indirect biochemical tests on the catheters, after the first clinical use and in situations of simulation with ATS for up to 5 reuses.Regarding the results of the cleaning tests, none of the methods were effective in the complete removal of organic residue intentionally added to the catheters.These results may be indicative of the presence of biofilms on these devices.In the conclusion of the study, the author reinforces the need to establish maximum acceptable parameters of organic residues and to carry out clinical observational studies which permit the determination of the clinical significance of the presence of such residues (carbohydrate, protein and hemoglobin) and of endotoxins.
One of the alerts in the discussion of reuse of single-use devices is the evaluation of the functionality of the material before exploring the possibility of achievement of sterility.A study, conducted in Germany in 2008, demonstrated reliability in the single-use laparoscopic ultrasonic scalpel reprocessed once,