Introduction

Surgical site infection (SSI) dramatically decreased after Pasteur published the microbiological theory, and then Joseph Lister introduced the antiseptic approach in 1861. However, surgical site infection is still among the major health concerns of this century. In the United States of America (USA), it is reported that more than 60,000 surgical site infections develop each year¹,². “Centers for disease control and prevention (CDC)” predicts that this figure might be 10 times higher than reported³. Surgical site infection increases mortality, morbidity, and hospital costs significantly. This situation worries health professionals and health administrators enormously. In a study conducted by Badia et al., it has been reported that insurance systems costs in Europe are at least 2 times more in the hospitals where patients develop surgical site infection compared to the ones with no SSI patients⁴. Due to the concerns about the issue, practices and procedures not based on evidence are seen in many hospitals. Some regulations could negatively impact both healthcare costs and patient comfort. Our study’s point of departure is a common practice that transfers patients to operating rooms using different transfer stretchers at several stations. To understand how widely accepted this situation is, making a basic Internet search will be enough: more than 150.000 results and hundreds of different types of stretchers appear on the “Google” search engine if you look for the results of “operating room transfer stretcher.” However, according to the literature, neither in reputable international guidelines nor in national guidelines are there evidence-based recommendations about transferring patients to operating rooms on stretchers to prevent surgical site infections. “Asia Pacific Society of Infection Control” (APSIC) manual briefly lists age (> 65), obesity, malnutrition, smoking, immunosuppression, hypoalbuminemia, and prolonged hospitalization as preoperative risk factors for SSI. Perioperative risks are urgent and/or complex surgery, high wound class, insufficient ventilation, heavy operating room traffic, inappropriate skin preparation, inappropriate hand hygiene, inadequate surgical instrument sterilization, inappropriate antimicrobial prophylaxis, unbathed patients before surgery, prolonged operation time, blood transfusion, improper surgical technique, hypoxia, and hypothermia⁵. Sufficient nutrition, administration of the appropriate prophylactic antimicrobial agent, glycemic control (< 200 mg/dL), normothermia, oxygenation, and performing antisepsis are recommended in the first step in CDC’s surgical site infection prevention guideline⁶. Wound type, American Society of Anesthesiologists (ASA) score, operation time, hand hygiene, antimicrobial prophylaxis, appropriate skin preparation, normothermia, glycemia control, urgent operation, operation room’s closed door, and room traffic intensity are reported as risk factors for surgical site infections in the European guidelines⁷.

This study was conducted in an area hospital in Istanbul between 2018 and 2019. To determine the development of SSI, we made a retrospective comparison between 1 year (2019) during which patients were transferred to operating rooms with patient beds and another year (2018) during which patients were transferred to operating rooms with patient transfer stretchers. Moreover, the results were analyzed to determine whether the patient transfer type had a role in developing surgical site infection.

Material and methods

This study was conducted with approval from the ethics committee of an area hospital (Ref No. 2719, Date: February 5, 2021).

At the beginning of 2019, our institution’s quality management unit realized patient falls during the patient transfers to operating rooms. Then, they revised the transfer procedures by obtaining the approval of the hospital’s infection control committee. Earlier, a patient was first taken from his/her service bed to a transfer stretcher, and (s) he was carried to the operating room’s entrance area where (s) he was taken to another (transfer) stretcher and then carried to the room before (s) he was finally put on the operating table. Following the operation, the patient was first taken to a transfer stretcher and brought to the operating room’s exit door at the end of the compilation process period. Next, (s) he was taken to another transfer stretcher that came from his/her surgical service and carried to the service where (s) he was finally put on his/her bed. However, after 2019, newly cleaned linens were put on patient beds first, and then patients were directly taken to the operating table on their beds. They were transferred to their services with the same bed at the end of their surgeries. The patients’ cots were cleaned according to the standard cleaning procedure.

As part of this study, the data of 1751 patients whose transfers to operating rooms were done with stretchers, and the data of 1817 patients whose transfers to operating rooms were done with their beds were compared. All patients were operated on in the hospital’s general surgery clinic. The patients were examined in two groups: the first group was named transfer with stretcher group (ST) and operated in 2018, while the second group was called the transfer with the patient bed (PBT) and operated in 2019.

Related patient data were extracted from the hospital’s information management system’s electronic database and the patients’ files. Hospital ventilation system records and hand hygiene compliance rates were obtained from the hospital’s quality management unit. Surgical site infection rates were obtained from the hospital’s surveillance records. The formula of “SSI number/number of operations × 100” was used in calculating the SSI rate. The diagnosis of SSI was made by the criteria of “CDC” and Turkey’s “National Health Service Associated Infections Surveillance Guide.” Cases with perforated appendicitis, diverticulitis perforations, delayed gastric ulcer perforation, abdominal penetrating stab injuries, abdominal gunshot injuries, and abscess drainage were excluded from both groups. As a result, 52 patients from the ST group and 45 patients from the PBT group were excluded from the study. Thus, 1699 patients from the ST group and 1772 patients from the PBT group were included. All patients were operated on in the same operating unit. However, the emergency patients were operated in the unit’s operating room allocated to the emergency, while the others were operated in the operating rooms reserved for elective cases.

The groups’ age and gender distributions, ASA scores, wound class, albumin levels, blood glucose levels, minimally invasive surgery rates, and operation times were analyzed by comparison. Besides, the distribution of the surgery types (electively or urgently), presence of blood transfusion, the operating rooms’ particle class and room project class, and the hand hygiene compliance rates of the hospital were analyzed in the same way.

The term “surgery types” was used to describe whether the surgery was performed urgently or electively. “Minimal invasive surgery rate” was used to express whether the surgery was performed by a laparoscopic or conventional method. “The presence of hyperglycemic state” was used to indicate the patients whose blood glucose levels were above 200 mg/dL. The patients with an albumin level lower than 2.5 mg/dL were accepted as patients with hypoalbuminemia. The term “Class 1” was used for clean wounds, “Class 2” for clean-contaminated wounds, “Class 3” for contaminated wounds, and “Class 4” for dirty wounds.

Results

There were 1699 patients in the ST group and 1772 patients in the PBT group. About 47.5% (808) were female in the ST group, and 52.5% (891) were male. About 49.3% (874) were female in the PBT group, and 50.7% (898) were male. There was no statistically significant difference between the groups regarding gender distribution (p = 0.298). The gender distributions of the groups are shown in table 1. There was no statistically significant difference between the age distributions of the groups (p = 0.072). The mean age was 44.86 in the ST group and 45.71 in the PBT group. The age distributions of the groups are shown in table 1.

The distribution of the ASA scores between the groups is shown in table 1. There was no statistically significant difference between the ASA scores of the groups (p = 0.221). In both groups, the presence of hyperglycemia was analyzed categorically, and no statistically significant difference was observed between the groups (p = 0.217). Hyperglycemia was detected in 24.3% of the patients in the ST group and 26.1% of the PBT group patients. The distribution of hyperglycemic states among the groups is shown in table 1. Only three patients in the PBT group had albumin levels below 2.5 mg/dL.

About 4.3% of the cases were operated urgently in the ST group, and 95.7% were elective. In the PBT group, 6.4% of the patients were operated on urgently, and 93.6% were elective. When the distribution of the surgery types was compared, a statistically significant difference was found (p = 0.005). The distribution of the surgery types between both groups is shown in table 1. In addition, a statistically significant difference was found when both groups’ operation durations were compared (p = 0.023). The mean operation duration in the ST group was 54.96 min and 56.52 min in the PBT group. The comparison of the operation durations between the groups is shown in table 1.

Laparoscopic surgery was indicated in 1200 patients in the ST group, but 74.2% underwent laparoscopy. On the other hand, in 1272 patients in the PBT group, laparoscopic surgery was indicated, but 72.8% had a laparoscopy. There was no statistically significant difference between the groups in that respect (p = 0.441). Table 1 shows the distribution of the patients who were operated on laparoscopically.

The distribution of wound classes between the groups is shown in table 1. There was no statistically significant difference between the groups regarding wound classes (p = 0.292).

Two units of blood were transfused preoperatively to two patients in the ST group and three patients in the PBT group.

Both groups’ operating rooms were compared in particle class and room class. No difference was found between them. Table 2 shows the data of the room-based distribution of the operating room ventilation system between the groups.

While the hospital handwashing ratio was 84% in the ST group, it was 87.3% in the PBT group.

Surgical site infection developed in 43 patients with a rate of 2.5% in the ST group. In the PBT group, 49 patients developed surgical site infection with a rate of 2.8%. Of the ST group patients who developed surgical site infection, 11 were urgently, and 32 were electively operated on. Of the operated patients in the PBT group, 16 underwent surgery urgently, and 33 were elective. No statistically significant difference was found when the groups were compared according to the development and non-development of surgical site infection (p = 0.667). The distribution of surgical site infections among the groups is shown in table 3.

Multi logistic regression analysis was performed to understand whether the parameters affected the probability of SSI development. Table 4 shows the results of the analysis. It was observed that wound Class III increased the probability of surgical site infection by 2.6 times compared to wound Class I, emergency surgeries increased the probability of surgical site infection 2.9 times compared to elective surgery, and hyperglycemia increased the probability of surgical site infection 2.3 times. It was observed that the effects of gender and ASA score, and the transfer type of the patient on the probability of surgical site infection were not statistically significant. The types of patient transfer had similar effects on the probability of SSI development. In the analysis, the odds ratio was 1.095 (95% CI: 0.723-1.659) for stretcher transfer according to patient bed transfer.

Discussion

Surgical site infections are infections in the incision line or on the deep tissues and organs that occur 30 days after a surgical procedure or within a year after an implant operation. The incidence of SSI could be up to 20%, depending on the surgical procedure, the surveillance criteria used, and the data collection quality. The responsible pathogens in many SSIs arise from the patient’s endogenous flora. The causative pathogens depend on the type of surgery; the most frequently isolated organisms are Staphylococcus aureus, coagulase-negative Staphylococci, Enterococcus spp., and Escherichia coli⁸,⁹.

Nowadays, surgical site infections are still debated, increasing morbidity and mortality. Most of the time, factors related to patients and surgery types affect the risk of developing SSI. Even if epilation, skin preparation, and preoperative antibiotic prophylaxis are used to reduce SSI, there are many risk factors related to the surgical application, such as blood loss during surgery, surgery under emergencies, and the duration of the operation¹⁰. Therefore, it is thought that there might be numerous risk factors concerning the issue, and they are still under investigation. It has even been studied whether the development of surgical site infection is associated with seasons and warmer weather¹¹.

It is highly controversial whether the risk of developing surgical site infection is related to gender. Aghdassi et al. described 10-year surveillance results, saying that gender may pose a risk for surgical site infection for specific procedures. While examining the underlying risk factors for SSI, they stated that there might be differences between male and female patients, but more information is needed to explain the differences fully¹². No statistically significant difference was found in gender distributions between the groups in our study. Our study observed that gender did not change the probability of surgical site infection, and there was no statistically significant difference in its effect.

Advanced age is a risk factor associated with increasing the SSI rate in many studies. In the Asia Pacific Society of Infection Control (APSIC) guideline, it is stated that age up to 65 is a risk factor for the development of surgical site infection⁵. Besides, CDC expressed in its guideline that age is a risk factor that increases patient-related surgical site infection⁹. No statistically significant difference was found in our study between the groups’ age distributions (p = 0.072).

ASA scores and Charlson comorbidity index (CCI) have a strong influence on the increase of surgical site infection rates if there are ‘Class 1’ and ‘Class 2’ wounds⁷,¹³. In the CDC guideline, it has been reported that ASA score increases surgical site infection along with prolonged surgery time and wound class. Its level of evidence is reported to be “Category IB”⁹. No statistically significant difference was observed in our study between the groups’ ASA scores (p = 0.221). In a study Carvalho et al. conducted, they have discovered that patients in the ASA II, ASA III, and ASA IV groups are at the risk of developing surgical site infection¹⁴. Our study observed that ASA scores did not change the probability of surgical site infection, and there was no statistically significant difference in its effect.

Diabetes appears to be an independent risk factor for SSI development¹⁵. In CDC’s 2017 guideline, blood glucose level was recommended to be kept under 200 mg/dL⁶. When the levels of HbA1c (glycosylated hemoglobin) are 8% and above, it is also defined as chronic hyperglycemia and diabetes¹⁶. In some studies, HbA1C values with 8% and above have been reported to be threshold values for developing surgical site infection in orthopedic and cardiac surgery¹⁷,¹⁸. The guideline of APSIC recommended keeping HbA1C (values) below 8% preoperatively to avoid surgical site infection and says its level of evidence is category IIIC⁵. In the CDC guideline, preoperatively, controlling hyperglycemia is recommended as category IB in evidence level⁹. The effect of hyperglycemia on surgical site infections could be multifactorial. Furthermore, diabetes increases comorbidity. In our study, no statistically significant difference was observed between the groups in (terms of) the presence of hyperglycemia (p = 0.217). In multi logistic regression analysis, it was observed that hyperglycemia increased the probability of surgical site infection 2.3 times.

It is reported in the literature that a long operation time increases the risk of SSI. Cheng et al. recommended that hospitals focus on shortening the operation time, given its importance for health-care economics¹⁹. Carvalho et al. have also emphasized that long operating times are a risk factor for surgical site infections¹⁴. A statistically significant difference was found between the groups’ operation durations in our study. The mean operation time in the ST group was 54.96 min, and it was 56.52 min in the PBT group. Hence, the operation duration was longer in the PBT group. However, the literature has reported that prolonged operation time increases (the risk of) surgical site infection along with high ASA score and contaminated wound class⁵,⁹.

Surgical site infection is one of the most common complications after an emergency abdominal surgery¹⁰,²⁰. When the distribution of the surgery types between the groups was compared, a statistically significant difference was found in our study. This difference was thought to be the significantly higher number of emergency surgical operations in the PBT group. Our study observed that emergency surgeries increased the probability of surgical site infection 2.9 times compared to elective surgery.

In particular, minimally invasive surgeries are fundamental in preventing surgical site infection⁹. Golub et al. analyzed their surveillance data, showing that laparoscopic operations have lower SSI risks than open operations in appendectomy cases²¹. This condition is also valid for laparoscopic colectomies²². Therefore, it is clear that laparoscopic surgeries differ from open surgeries significantly in SSI development because they are a lot less likely to lead to surgical site infections²³. There was no statistically significant difference between the groups in this regard (p = 0.441).

According to the literature, a higher SSI rate is observed in the patients with comorbidities in clean and clean-contaminated wound class than those without comorbidities¹³. In the guideline of APSIC, the increased wound class category is reported to be a pre-operative risk factor⁵. In CDC’s guideline, the role of determining wound class in surveillance is at Category II in terms of the level of evidence⁹. As mentioned above, ASA score increases surgical site infection, prolonged surgery time, and contaminated wound class, and its level of evidence is reported to be “Category IB”⁹. No statistically significant difference was found between the groups concerning wound classes (p = 0.292).

Low serum albumin levels are significantly associated with the development of surgical site infections, especially in elderly patients. In particular, serum albumin levels should be closely monitored in patients with comorbidities before and after surgeries²⁴. In our study, three patients in the PBT group had albumin levels below 2.5 mg/dL. On the other hand, the literature has reported that perioperative blood transfusion is associated with the development of surgical site infection²⁵-²⁷. Furthermore, among SSI risk factors, blood transfusion has been shown both as a perioperative and a post-operative risk factor in the guideline of APSIC⁵. In our study, two units of blood transfusion were applied perioperatively to two patients in the ST group and three patients in the PBT group.

Surgical site infection rates are greatly affected by the facility’s structural features and systems and the quality of operating rooms determined by health-care professionals’ management and behavior²⁸. However, according to the meta-analysis performed to determine laminar airflow systems’ role in preventing SSI in general and cardiovascular surgeries, there was no statistically significant difference between the two operation types under the system⁵. In some studies, a statistically significant relationship was found only in the patients who underwent knee arthroplasty. Therefore, in the guideline of APSIC, no evidence-based recommendation is presented for laminar flow⁵. Moreover, Bischoff et al. suggested that the laminar flow model is not installed in new operating rooms²⁹. In our study, both groups’ operating rooms were compared in room pressure, supplied airflow rates, air changes, relative humidity, temperature, particle class, and room class. No statistically significant difference was found between them.

Unfortunately, hand hygiene compliance rates do not appear quite good in the literature. The percentage of its practice around the world is below 50. However, one of the best weapons in reducing the risk of contamination is washing hands³⁰,³¹. In our study, while the hospital’s hand hygiene compliance rate was pretty good in both groups.

There is no doubt that surgical site infection significantly increases mortality, morbidity, and hospital costs. Naturally, this situation worries health professionals and health managers excessively. In a study conducted by Badia et al., it has been reported that insurance systems costs in Europe are at least 2 times more in the hospitals where patients develop surgical site infection than those with no SSI patients⁴. However, it should not be forgotten that laminar flow systems, which do not have any prospective evidence, have given way to high health-care costs in the recent past due to our concerns. However, when the literature is examined, it is seen that this high-cost technology is no longer recommended to prevent surgical site infections⁵,⁹,²⁹.

Similarly, wearing overshoes before surgeries were once strongly advised to prevent SSI, but it is not practiced anymore. There is no evidence that the patient’s transfer to the operating room with his/her bed or the stretcher exchange system increases the risk of surgical site infection in the manuals and the studies on this subject. The CDC, APSIC, and European guidelines do not provide any recommendations about the issue⁵,⁹. Although it has been told in some studies that bed linen may have increased the risk of “hospital infection,” it is unknown whether it poses a risk for SSI³². The relationship of bed linens with (the development of) surgical site infections does not go beyond our assumptions. Despite the evidence, patients are transferred to operating rooms on stretchers in many hospitals. In our opinion, this is an unnecessary practice and affects patient comfort adversely. However, it seems the health-care industry has benefitted from this practice considerably.

A simple “Google” search about operating room transfer stretchers reveals more than 150 thousand results and hundreds of transfer stretchers (Date of access; January 30, 2021). Our study observed that surgical site infection developed at 2.5% in the ST group and 2.8% in the PBT group. Although the groups were similar to each other in terms of the factors mentioned in the literature and the PBT group was more prone to SSI due to (higher number of) emergency surgery patients and long operation times, there was no statistically significant difference between the groups in terms of development of SSI. Both types of patient transfer had no effects on the possibility of SSI development. However, it is safer and more comfortable to transport the patient with her/his bed.

This article criticizes the patient transfer technique with a stretcher, which is traditionally accepted by health-care providers, from a different perspective. Many health-care providers seem to have unconditionally accepted patients’ transfer to the operating room on a stretcher. This acceptance is based on the assumption that transferring the patients by the patient bed will increase the wound infection. However, in our study, it was revealed that there was no significant increase in wound infection rates. Furthermore, patient transfer with a stretcher brings along patient-related problems such as post-operative pain, patient dissatisfaction, and discomfort, negatively affecting the employee’s health in the long-term and skeletal system deformities. On top of all this, transfer stretchers also place an additional burden on the health system, which is sufficiently financially burdened. Therefore, the ultimate goal of this study is to revolutionize the use of stretchers, which are widely used in patient transfer and impose a financial burden on health institutions.

Conclusion

It is relatively comfortable and safe to transfer patients to operating rooms on their beds. Besides, there is no evidence that it increases the risk of surgical site infection. Nevertheless, surgical site infections are still on health professionals’ agenda as it plays a role in mortality and morbidity. Hence, it is natural to worry about the issue. However, it is safer and cheaper to act based on evidence instead of trusting our concerns.