The role of blood transfusion in the occurrence of surgical site infection amongoperated patients at Muhimbili Nationalhospital, Dar Es Salaam.

Abstract

ABSTRACT Background Several studies have shown that allogeneic blood transfusions can induce clinically significant Immunosuppression referred to as transfusion-associated immunomodulation (TRIM). TRIM has been linked to an improved clinical outcome in the setting of renal allograft transplantation. TRIM-associated effects include an increased rate of cancer recurrence and of post-operative bacterial infection.

This study was carried out to determine the prevalence and factors associated with Surgical Site Infection among post-operative surgical patients following exposure to blood transfusion in the surgical units of Muhimbili National Hospital. Methodology A nested case control study was carried out at the surgical units of Muhimbili National Hospital from May through December 2017. The study involved two groups of post-operative patients (i.e. those who were transfused and those post operatives who had not been exposed to blood transfusion) admitted to the surgical wards. Study subjects were recruited conveniently until the desired sample size was achieved. A well-structuredquestionnaire containing socio-demographic characteristics, patient’s preoperative, perioperative and postoperative information was administered to study subjects who met the inclusion criteria and consented to participate in the study. Data was checked for completeness, coded and entered into SPSS version 22. Frequencies, proportions and measures of central tendency and measure of dispersion were calculated. Odds ratio was used as a measure of association.

Results A total of 200-study participants were recruited during the study period. The median age was 47.5 years with a range of 12 to 94 years. Majority of respondents were female (53%) while age group 45 year and above constituted 57%. More than half of the study respondent had HB level of 11 g/dl and above. With regards to hospital stay, 58% stayed less than 7 days. 93 study respondents (47%) were transfused during surgery with more females transfused compared to males (58% vs. 42%) while age group 45 years and above had the highest cases of those who were transfused. Twelve percent of those who were transfused developed surgical site infection. There was nearly equal number of males (9) and females (8) participants who developed surgical site infection with participants in the age group above 45 years, those with Hb level below 11g/dl and participants with hospital stay more than seven (7) days having developed more cases of surgical site infection.

Conclusion This study has failed to reject the null hypothesis hence but has shown a possible increased risk for SSI among patients receiving BT. Although many studies have shown the association between BT and overall infection, there is scant literature on the association between BT and specific infections. Low hemoglobin, which is related to BT, was however shown to have significant increased risk for occurrence of SSI. Similarly, prolonged hospital stay was also found to have increased risk of SSI development. Smoking was however found to be the most important factor in the occurrence of SSI in our cohort of patients. Due to frequent complications seen in transfused patients, a more restrictive transfusion practice may be safe and efficient. Patients undergoing BT were more likely to experience complications and that the triggering level of Hb and target of transfusion should be restricted. Recommendations • Further studies that are surgery specific to assess the role of blood transfusion influence on surgical site infection. • Counseling the surgical patients on cessation of smoking at least two weeks before surgery to scale down on the adverse effects of cigarette smoke on wound healing. • Adhere to established guideline in preoperative preparation to optimize postoperative outcomes.