A Study of Risk Factors of Surgical Site Infection in one Center: A Cross-Sectional Study

Introduction

Suspected surgical site infection (SSI) is termed for any infection take place in the first 30 days after a surgical procedure. It is cat-egorized to two: superficial SSI, which involves only the skin and underlying subcutaneous tissue, and deep SSI, which involve in-vade the fascia and the muscle [1].

Many factors contribute to SSI such as underlying diseases, burns, hospital environment, or even the patient’s flora [2].

Nowadays, SSIs are considered a serious complication that occurs after any surgical procedure for about 2%. In addition, SSIs are classified in third rank among common nosocomial infections, next to the urinary tract and respiratory tract infections [3,4].

Important patient-related factors increasing the risk of an SSI in-clude pre-existing infection, malnutrition, obesity, low serum albu¬min, elderly, smoking, and immunosuppression (diabetes mellitus, irradiation). Surgery-related factors include contaminated sur¬geries, emergency surgeries, prolonged procedures, substandard sterilization, inadequate handling of instruments, and inadequate antiseptic surgical site preparation. Physiological conditions that predispose to an increased incidence of SSI include multi-trau-ma, hemodynamic instability, shock, massive blood transfusions during the procedure, and postoperative hypothermia, hypoxia, and hyperglycemia. Other independent predictors of SSI include abdominal surgeries, contaminated or dirty procedures, and three or more diagnoses upon hospital discharge [1].

For this, we conducted a cross-sectional study for one month in one center to see the incidence and the risk factor of SSI after ab¬dominal and urological surgeries.

Material and methods

A prospective cross-sectional study was performed in a tertiary hospital from May 1, 2023 to May 31, 2023 (one month). All data was extracted from the records after it was approved by the ethics committee.

Inclusion criteria were: age 18 or older, any type of abdominal or urological open surgery, and no documented history of infection at surgical site infection.

Exclusion criteria were: patients under age 18 years, onset surgical site infection after day 30, incomplete data, patients who are im-munocompromised or taking drug or any steroid, repeated surgical procedure, and other types of surgeries like head, thoracic, etc.

Firstly, all patients underwent full examination with a detailed his-tory.

Details such as age, gender, comorbidities (diabetes mellitus, hy-pertension, obesity, and smoking), and type of surgery (emergen-cy, elective) were all studied.

Investigations such as blood tests, urinalysis, abdominal ultra-sound, chest x-ray, and upright position abdominal x-ray were all studied according to the patients’ status. Vital signs including: blood pressure, heart rate, pulse, respiratory rate, and temperature were all taken and documented. After surgery, signs and symptoms of surgical site infection such as: fever, edema, discharge, redness, and warmth were noticed after 24 hours of surgery. SSI was di¬agnosed clinically by the physician or the same surgeon. Wounds were classified clean, clean contaminated, contaminated, dirty.

Patients with signs and symptoms of SSI were evaluated by com¬plete blood count, CRP, sample f discharge for culture. Then, an appropriate antibiotic was introduced according to the culture. Our data were processed and analyzed using IBM SPSS Statistics for Windows, version 23. P-value of less than 0.05 was considered statistically significant.

Results

We had 134 patients. Only 111 patients had a completed data were included. The others either some data were missed or they had incomplete data. Total number of males was 62 (55.8%) patients, whereas the number of females was 49 (44.1%). In this study, we had only 15 (24.1%) male patients who developed surgical site infection (SSI). In contrast, 9 (18.3%) female patients developed SSI. P-value was insignificant as shown in Table 1.

The total number of patients who were 40 years old or younger was 60 (54 %) and only 10 (16.6%) patients developed SSI. Pa¬tients whose age older than 40 years were 51 (45.9 %) and only 18 (16.2 %) patients had SSI. Here, there was a statistically signifi¬cant (Table 1).

We had two types of procedures: emergency and elective. In this study, we had twelve cases which were emergent. Eight of twelve patients (66.6%) had later SSI. On the other hand, 99 of cases (89.1%) were elective surgeries and only two patients (2 %) de¬veloped SSI after 24 hours of surgery. P-value was statistically significant (0.003).

In term of hospital stay, we had 70 patients (63 %) were admitted only 24 hours or less before surgery. Out of the seventy patients, ten of them developed SSI (14.2 %). Patients who were admitted more than 24 hours in the hospital before surgery were 41 (36.9 %) and only 10 patients (24.3 %) of them had SSI. P-value here was significant.

According to wound classification, we had 54 patients who had clean wound. Five of them demonstrated SSI later. Clean-contam-inated wound number was 31 patients. Only eight (25.8 %) of the cases had SSI. Sixteen patients had contaminated surgical wound and nine patients (56.2 %) had SSI. Dirty wounds were in 10 pa¬tients out of 111. Three patients developed later SSI. The results were not statistically significant.

Table 1: Factors Associated With Ssi.

In term of comorbidities, we studied just four factors. We had 14 patients (12.6 %) who had hypertension and only six of them (42.8%) developed SSI (Table 2).

Diabetes mellitus was the second most common comorbidities in our study (19) patients after smoking (22) patients. Nine (47.3 %) and eleven (50 %) patents diagnosed with SSI later, respectively.

Obesity was another important risk factor for SSI. Seventy pa- tients had obesity and 8 of them suffered from SSI (Table 2).

                                                Table 2: Comorbidities that May Increase the Incidence of SSI.

Discussion

In this study, we had 134 patients in total and only 111 cases were studied according to our inclusion criteria. In May, 2023 we per¬formed a cross-sectional study to demonstrate the risk factors to the surgical site infection. In accordance to the literature, surgical site infection is considered a real problem for both patients and doctors. Many previous studies tried to evaluate and assess the risk factors and how to avoid them. This may reduce in costs and in¬crease the perioperative care and post-surgery.

Our study concentrated on abdominal and urological surgeries. The overall proportion of SSI in this study was 21.6 %. A study done by Allergens et al also reported that abdominal surgeries are commonly done and have high rates of SSIs [5].

We had 55.8 % of patients were males and 44.1 % were females’ patients. Our study showed no statistically significant for SSI oc-currence and its association with gender as a risk factor. A study done by Shanmugam et al. reported almost equal occurrences among females (52%) and males (48%) [6].

Increasing age is associated with a greater likelihood of certain chronic conditions and delayed healing which is most probably the cause of the increased incidence in higher age groups [7].

We had in this study patients with age 40 years or younger were the most (60 patients), whereas patients with age older than 40 were 51 years. The occurrence of SSI according to the age was 10, and 18 patients’ respectively. There was a statistically significant.

Most of the surgeries were done electively (89.1 %). Only two patients (2%) developed SSI. Emergent surgeries found in 12 pa-tients, and 66.6 % of them developed SSI. Another study showed SSI rates to be higher in emergency procedures [8].

In another study done by Dessie et al., SSIs were reported in 61.7% of emergency cases and 38.3% of elective cases [9].

The same has been cited in most of the studies done earlier on SSIs. Tabiri et al. also reported that emergency cases had a higher number of SSIs (23.8%) as compared to elective cases (7.4%) [10].

Regarding the relationship between SSI and wound classification, we found 54 patients had clean wounds and only 9.2 % of them de¬veloped SSI. Thirty-one patients had clean-contaminated wounds and 25.8 % of them had SSI later. Patients with contaminated or dirty wounds developed SSI 56.2 % and 30 %, respectively.

As found in previous studies, hospital stay has a negative impact on SSI incidence. Patients who admitted more than 24 hours had SSI (24.3 %) which is a higher incidence than patients who admit¬ted 24 hours or less before procedure. There is a statistical signifi¬cance (p-value= 0.002).

Co-morbidities, such as obesity, smoking, hypertension, and dia-betes mellitus, are other approved risk factors for developing SSI. Morbid obesity has been correlated with prolonged wound healing which is a known risk factor for deep SSIs [11].

Table 2 shows comorbidities that may increase the proportion of SSIS.

Conclusion

Our study demonstrated a higher incidence of SSI after abdominal and urological surgeries. Emergency surgery, elderly patients, long hospital stay, male gender, and contaminated wound are consid-ered to raise the risk for SSI. Larger and multicentric studies are required to see the real number of patients and to expect the most significant risk factors for SSI after surgery.

References

1. Ansari, S., Hassan, M., Barry, H. D., Bhatti, T. A., Hussain, S.Z. M., Jabeen, S., & Fareed, S. (2019). Risk factors associated with surgical site infections: a retrospective report from a de­veloping country. Cureus, 11(6).
2. Barana, L., Gastaldo, L., Maestri, F., Sgarella, A., Rescigno, G., Prati, U., ... & Zonta, A. (1992). Postoperative infections. A prospective analysis of 1396 cases. Minerva chirurgica, 47(13-14), 1177-1187.
3. Mangram, A. J., Horan, T. C., Pearson, M. L., Silver, L. C., Jarvis, W. R., & Hospital Infection Control Practices Advisory Committee. (1999). Guideline for prevention of surgical site infection, 1999. Infection Control & Hospital Epidemiology, 20(4), 247-280.
4. Emori, T. G., & Gaynes, R. P. (1993). An overview of nosoco­mial infections, including the role of the microbiology labora­tory. Clinical microbiology reviews, 6(4), 428-442.
5. Allegranzi, B., Nejad, S. B., Combescure, C., Graafmans, W., Attar, H., Donaldson, L., & Pittet, D. (2011). Burden of endemic health-care-associated infection in developing countries: systematic review and meta-analysis. The Lancet, 377(9761), 228-241.
6. Shanmugam, G., Rangam, S., Kayalvili, K. K., & Sundaram,L. (2017). Prevalence of surgical site infections and antimi-crobial sensitivity pattern in patients attending a Tertiary Care Hospital in South India: A prospective study. Journal of Pa­tient Safety and Infection Control, 5(1), 12.
7. Sattar, F., Sattar, Z., Zaman, M., & Akbar, S. (2019). Frequen­cy of post-operative surgical site infections in a Tertiary care hospital in Abbottabad, Pakistan. Cureus, 11(3).
8. Osakwe, J. O., Nnaji, G. A., Osakwe, R. C., Agu, U., & Chineke, H. N. (2014). Role of premorbid status and wound related factors in surgical site infection in a tertiary hospital in sub-Saharan Africa. Family Practice Reports, 1(1), 2.
9. Dessie, W., Mulugeta, G., Fentaw, S., Mihret, A., Hassen, M., & Abebe, E. (2016). Pattern of bacterial pathogens and their susceptibility isolated from surgical site infections at selected referral hospitals, Addis Ababa, Ethiopia. International jour­nal of microbiology, 2016.
10. Tabiri S, Yenli E, Kyere M, Anyomih TT: Surgical site in­fections in emergency abdominal surgery at Tamale Teaching Hospital, Ghana. World J Surg. 2018, 42:916-22.
11. Cordero-Ampuero, J., & de Dios, M. (2010). What are the risk factors for infection in hemiarthroplasties and total hip arthroplasties? Clinical Orthopedics and Related Research®, 468, 3268-3277.