Title: Sterile Regions of an Operating Gown during a Lower Limb Joint Replacement Surgery
Author(s): Mohammad Reza Abbasian MD, Seyyed Mohammad Qoreishi MD*, Ali Akbar Esmailiejah MD
Affiliattion(s): Shahid Beheshti University of Medical Sciences, Tehran Iran
* Corresponding Author
Vol 2, Num 1, January 2015
Introduction:Surgical intervention is associated with an inherent risk of postoperative wound infection. Contamination of the operative field is a major concern to all orthopaedic surgeons. However, this concern is much bigger for arthroplasty surgeon. The aim of this study was to determine the boundaries of the most sterile part of the surgical gowns used during arthroplasty procedures at the beginning and the end of the index procedures.
Materials and Methods:We took cultures from 32 sterile disposable surgical gowns (sterilized by ethylene oxide) from a series of 8 surgical cases performed by one surgeon. These swabs were streaked on one quadrant of a 5% sheep blood agar plate, which is a standard, nonselective media that is known to support the growth of numerous bacterial strains, including Gram-negative and Gram-positive species (eg, Staphylococci and Streptococci).
Results:Bacterial growth was observed most frequently in the areas above the chest (27%–44%) and below the operating room table (17%–23%). In contrast, the portion of the gown between the chest and the operating room table had the lowest contamination rates (6%–9%). Likewise, 23% of swabs acquired from the elbow creases and 24% and 36% of the swabs taken from 5 and 10 cm above the elbow crease, respectively, were contaminated after surgery.
Conclusion:Based on our data, we regard the front of the gown between the operative table and the chest to be the area of greatest sterility and we strongly advise scrubbed personnel to avoid contacting the surgical field with their elbow creases to minimize the risk of infection.
Keyword:Operating Gown, Sterile Site, Joint Replacement, Bacterial Infection
Each and every surgical intervention is associated with an inherent risk of postoperative wound infection. This complication may dramatically alter the clinical course of an affected patient. As a result, every effort is made by the surgeon and operating room staff to adhere to proper sterile techniques to decrease the chance of surgical-site infections.
Contamination of the operative field is a major concern to all orthopaedic surgeons. However, this concern is much bigger for arthroplasty surgeons because the results of a very satisfying orthopaedic procedure will turn into a real catastrophe by surgical site infection after arthroplasty. Sometimes, the only treatments for this complication are prosthesis removal or amputation.
Some factors associated with a higher risk of surgical-site contamination include the use of power equipment, insertion of a large implant, larger number of personnel present in the operating room and sometimes, longer operating time.(1,2) Ritter et al. reported a 35-fold decrease in colony-forming units per hour in an empty operating room versus when five people were present.(1,2)
Surgical instruments and other equipment used in the operative field with reported contamination rates are light handles (0% to 14%),(3,4) sucker tips (11% to 41%),(3, 5, 6, 7) scalpel blades (9%),(3) and fascial needles (10%).(3) Similar studies assessing the sterility of operating room staff have been performed: glove contamination has been documented in 14% to 57% of orthopaedic cases depending on the subspeciality.(3,8, 9, 10) To minimize the risk of surgical-site contamination, guidelines have been presented regarding which portions of a gown may be considered sterile. The Association of Perioperative Registered Nurses (AORN) suggests the front of the gown is sterile between the levels of the chest and the operative field.(10)
During arthroplasty surgery of large joints, there are many points that may increase the contamination rate. Many large and heavy instruments must be used which are prone to be touched by those parts of the gown that may be contaminated. During some steps of the operation, some pats of the patients may have to be placed lower or upper than the clean area of the gown. So, if we accurately and with documents determine the clean areas of a surgical gown used during arthroplasty, we can prevent some inadvertent contaminations of the surgical site.
To reliably accomplish this goal, the boundaries of the sterile field must be clearly defined; however, at this time, the relative risks of intraoperative contamination associated with specific regions of the surgical gown have not been characterized.
We designed this study to determine the boundaries of the most sterile part of the surgical gowns used during arthroplasty procedures at the beginning and the end of the index procedures.
Materials and Methods
We took cultures from 32 sterile disposable surgical gowns (sterilized by ethylene oxide) from a series of 8 surgical cases performed by one surgeon. We routinely use disposable gowns in our hospital because they are more impermeable to blood and other fluids compared with reusable gowns.(11)
We took culture samples from the front of each gown. Using sterile swabs, we cultured the front of each experimental gown at 15-centimeters increments starting from a location 50 cm above the ground and continuing cephalad up to the neckline of the gown. At each sampling point, the entire width of the gown front was sampled taking care not to contact the more lateral portions. We also sampled from both elbow creases and up to 10 cm above the elbow crease in 5-cm increments.
We took the samples at four situations: 1) Just before wearing the gown, the same points on the body or clothes of each person was also sampled. 2) Just before beginning the procedure. 3) At the completion of the procedure, just before taking off the gown. 4) Just after removing the gown, from the same points on the body or the clothes. The surgical cases from which the swabs were obtained were all clean total hip or knee arthroplasties. For each surgery, the master surgeon, two of his aids and the operative technician were sampled. So, for each operation, we took at least 208 samples which were all marked by numbers and the numbers were written down in a sheath that was not open to our microbiologist. In this way, the microbiologist was blind to the results of the cultures.
We excluded cultures of any staff that participated in application of dressing to patient; as such activities expose individuals to unsterile regions on the operative field or patient's skin.
We recorded the following data for each individual: total height and the distances from the floor to the shoulders, axillae, chest (nipple line), waist, and knees; level of the operating room table; duration the subject was in the sterile field; and total number of personnel scrubbed during the procedure.
Cultures were procured using the following protocol; the tips of sterile culture swabs initially were dipped in sterile saline to facilitate extraction of any contaminants present on the gown surface. The swabs were shaken gently to remove any excess fluid before being used to sample the gowns. As part of a well-accepted semiquantitative technique, these swabs were streaked on one quadrant of a 5% sheep blood agar plate, which is a standard, nonselective media that is known to support the growth of numerous bacterial strains, including Gram-negative and Gram-positive species (eg, Staphylococci and Streptococci).(10) We achieved successive dilutions by streaking the remaining three quadrants in succession, making sure to use a new sterile, disposable loop for each streaking maneuver.
Plates were incubated at 370C for 48 hours, after which they were evaluated for the presence of bacterial colonies; we graded each sample on a scale of 0 to 4+ based on the number of quadrants on each plate that showed positive growth. Any growth pattern of 1+ or higher was considered consistent with contamination.
To determine if a significant rate of contamination occurred at each 6-inch location on the gown, we performed a separate Fisher's exact test to compare the contamination rate of postoperative swabs with that observed for negative control swabs. Second, all cultures were pooled according to which of six regions of the gown the sample was collected from: axilla to the chest, chest to the waist, waist to the operating room table, operating room table to the knees, and above the elbow crease in each arm. We then compared the collective postoperative contamination rate of each of these groups with the rate of corresponding negative control swabs using a Fisher's exact test. We used SPSS software for all analyses.
Contamination or growth was observed in all 416 samples (100%) taken from the skin or clothes before wearing the gown by the team. Among the samples taken from the gown immediately after wearing it, in 4 samples from the uppermost area in the anterior part on the gown and 10 cm below the neckline were contaminated (one sample 1+ and the other ones 2+). The rest of the samples from newly worn gowns (412 samples) were negative or clean.
In the postoperative samples taken immediately before taking the gown out, contamination was detected in samples from all areas of the gown with a prevalence of 3.1% to 53% for different samples. Postoperative contamination rates at 65 cm or less (ie, 50 and, 65 cm) and 125 cm or greater (ie, 125 and 140 cm) relative to the ground were greater than those of the negative controls, whereas such a difference was not evident at the 80-, 95-, and 110-cm locations.
Bacterial growth was observed most frequently in the areas above the chest (27%–44%) and below the operating room table (17%–23%); contamination rates of these sections were greater than those of the negative controls. In contrast, the portion of the gown between the chest and the operating room table had the lowest contamination rates (6%–9%).
Likewise, 23% of swabs acquired from the elbow creases and 24% and 36% of the swabs taken from 5 and 10 cm above the elbow crease, respectively, were contaminated after surgery, a percentage that also was greater (p = 0.003) than the value associated with the corresponding negative controls.
And again all the samples taken at the end of the surgery from the skin or clothes of the personnel were contaminated.
Minimizing the incidence of surgical-site contamination during orthopaedic procedures is a major priority because development of a postoperative infection is a potentially devastating complication. Arthroplasty operations may be particularly predisposed to bacterial seeding of the wound due to multiple instrumentations and the length of the procedure.
As no study has directly examined gown contamination and the risk of surgical-site infection, there are sparse articles considering the condition of surgical gowns. The only recommendation that the Center for Disease Control (CDC) currently has on the gowns is that they should be impermeable to liquids and viruses.(12) Among the numerous precautions that have been implemented to reduce contamination rates, the majority of surgeons would agree that selected regions of the gown are not sterile and should not be in direct contact with the operative field; nevertheless, the validity of these empiric guidelines have not been definitively established. We tried to better define which regions of the surgical gown should be considered most sterile by measuring the rate of contamination at specific body regions after arthroplasty procedures.
Despite adherence to standard aseptic surgical techniques, our findings indicate that immediately after wearing the gown, it seems reasonable to consider the upper m ost region of the gown contaminated. Although bacterial contamination may be identified in all areas of the surgical gown at the completion of surgical cases, certain portions of the gown clearly were involved more frequently than others.
According to our results, bacterial growth was observed most frequently in the areas above the chest (27%–44%) and below the operating room table (17%–23%); contamination rates of these sections were greater than those of the negative controls. In contrast, the portion of the gown between the chest and the operating room table had the lowest contamination rates (6%–9%). Likewise, 23% of swabs acquired from the elbow creases and 24% and 36% of the swabs taken from 5 and 10 cm above the elbow crease, respectively, were contaminated after surgery, a percentage that also was greater (p = 0.003) than the value associated with the corresponding negative controls.
We assume that bacterial shedding from the individual's head or mask may have compromised the sterility of the chest region. It also may be assumed that the portion of the gown below the operating room table most likely becomes contaminated from direct contact with any number of unsterile objects situated below the draped field. Moreover, the axillae may be exposed to greater amounts of perspiration, which would be expected to attenuate the impervious properties of the gown in this location.(13) These specific areas are considered unsterile based on recommendations provided by the AORN.(10)
By routine recommendations, the sterility of the gown sleeves extends proximally to 5 cm above the elbow crease.(10) We found elbow creases had a high contamination rate of 23% compared with that of negative control swabs. As with the axillae, the elbows may be subject to the deleterious effects of perspiration, which again may attenuate the impervious properties of the gown in this location.(13) Also, additional breaks in the sterility of this region may occur as the arms are tucked to the side so the elbows are positioned close to the side and rear portions of the gown.
Keeping these points in mind while performing arthroplasty of the lower limb is of paramount importance, since during this type of operation, the lower limb must be positioned in different conditions in space, whether near the face of the surgeon of below the level of operating table and so there is a great risk of contamination of the limb by contact between it and those parts of the surgical gown which are shown to be contaminated.
Based on our data, we regard the front of the gown between the operative table and the nipple line to be the area of greatest sterility and we strongly advise scrubbed personnel to avoid contacting the surgical field with their elbow creases to minimize the risk of infection.
There are some limitations to our study. The number of our samples was huge but the number of personnel committing the study was limited. We evaluated cultures only for positive growth, and specific bacterial isolates were not identified, and therefore we cannot comment on the clinical relevance of the isolates.
Mohammad Reza Abbasian MD Assistant Professor, Orthopaedic Surgeon, Shahid Beheshti University of Medical Sciences, Tehran, Iran firstname.lastname@example.org
Mohammad Qoreishi MD Assistant professor, Orthopaedic surgeon, Shahid Beheshti Medical University, Tehran, Iran Corresponding Author email@example.com
Ali Akbar Esmailiejah MD Associate Professor, Orthopaedic Surgeon, Shahid Beheshti University of Medical Sciences, Tehran Iran firstname.lastname@example.org
Acknowledgements: None declared.
Financial disclosure: None declared.
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