This retrospective observational cohort study highlights the role of the World Health Organization Surgical Safety Checklist (WHO SSC), particularly its Time-Out component, in influencing the incidence of SSIs after discharge. While the influence of the WHO SSC on the overall rate of SSIs was not clearly shown, our findings emphasize a noticeable increase in SSIs after discharge when the time-out checklist was not used. This is consistent with existing literature supporting the critical role of WHO SSC in reducing SSI odds after major abdominal surgery (29-31). Furthermore, the Time-Out component, has previously been identified as an element in reducing odds factors associated with SSI, by ensuring strict adherence to protocols such as verifying patient identity, surgical site and intended procedures, thereby minimizing the likelihood of errors leading to infections (32). Wæhle et al. found that when the surgical team closely follows SSC protocols, including timely antibiotic prophylaxis, verification of patient identity, surgical site, and planned procedure of intervention, they reduce the odds of misunderstandings and errors that can lead to infections (33). This is necessary for consistent and accurate use of SSC in a surgical setting. Our results support that these aspects are important to reduce SSIs especially after discharge, as demonstrated in previous studies (23, 29, 31, 32, 34-36). The mandatory use of the WHO SSC for the patient population in this study may influence the clinical significance of our results due to the already high baseline compliance. However, the observed discrepancies in the use of the WHO SSC during emergency procedures, particularly for caesarean sections, highlight an area for improvement. Despite the overall success of the checklist’s application, indicated by its use in 94% of all surgical procedures, our study reveals gaps in compliance, particularly in emergency settings. This finding is important for refining and targeting WHO SSC modifications to effectively address current surgical challenges (37). Our findings of lower use of the WHO Surgical Safety Checklist (SSC) during emergency procedures, especially caesarean sections, emphasizes the need for increased attention to compliance with checklists during such interventions. The WHO SSC was used in 94% of all surgical procedures. This can be considered a success and shows a sustainable use of the checklist. However, focusing on modifications of the WHO SSC is vital for addressing contemporary surgical issues (38), and to ensure that it is targeted and performed with quality (37).
Due to the nature of emergency cases, it may be difficult to ensure timely provision of prophylactic antibiotics. However, in a previous stepped wedge cluster randomized trial, the use of the WHO SSC improved the timeliness of antibiotic provision, and reduced the odds of wound ruptures and infections post operatively (39). The other identified perioperative SSIs risk factors i.e., surgical access, procedures, type of anaesthesia, and comorbidities are well-known and consistent with previous studies (10, 13, 15, 40-45). The significance of these factors suggests that risk assessments and prevention strategies should be personalized, reflecting the complex and multifactorial nature of surgical risks (13).
A large proportion of patients who developed SSIs after discharge in our study were women, which can partly be attributed to the composition of our patient population. Caesarean section is a procedure known to be associated with an elevated risk of SSIs especially in emergency settings. In addition, it is important to recognize that pregnancy induces physiological changes in the body, including an increase in body temperature (46, 47). This physiological shift may contribute to a higher incidence of hyperthermia (temperature > 37.5°C) among women who have undergone caesarean section (46, 47), as found in present study. These observations emphasize the necessity of a more personalized approach to risk assessment and infection prevention based on both the patient's gender and the specific surgical context.
In our analysis, we found a correlation between duration of surgery and risk of surgical site infections (SSI), in accordance with findings from previous research (10, 48). In particular, the risk of SSI increased with the length of the surgery, increasing per hour of duration of surgery (13, 49). These findings echo the conclusions of Cheng et al. (2017) (48) and Xu et al. (2021) (50), who also highlighted prolonged surgery as a significant risk factor for SSI. Our data consistently indicate that surgical duration is particularly associated with an increased risk of SSI after discharge, especially for procedures extending beyond 6 hours. The average duration of surgery of 2.48 hours in patients who developed an SSI after discharge emphasizes the importance of duration of surgery as a risk factor, in line with previous studies (50). Thus, our results reinforce the importance of adopting tailored surgical and perioperative strategies to minimize SSI risk, especially for extended surgeries. This includes not only vigilant adherence to infection control protocols, but possibly revisiting the planning and execution of surgeries to reduce surgical time without compromising patient care.
Beyond identifying possible perioperative SSI risk factors, our findings emphasize the need for a more holistic approach to risk assessment and infection prevention in abdominal surgery.
Strengths and limitations
Prior to data collection, power analysis suggested inclusion of 1140 patients would give a two-sided alpha at 5% with 90% strength, with 820 patients being normothermic and 320 being hypothermic. To ensure this, we included all relevant procedures performed between 2013-2018, providing data from 4142 patients which strengthened the possibility of assessing potential risk factors.
However, our study has some limitations. First and foremost, it is an observational study conducted at a single hospital studying associations and not causality, which may limit the interpretation of our findings. Secondly, the routinely recorded clinical data were collected from a patient operating theatre software program, which may have inaccuracies and impinge on the completeness of data registration. We hypothesized a U-shaped relationship between extreme perioperative temperatures - from hypothermia to hyperthermia - and the incidence of SSI. However, this expected pattern was not observed in our results, possibly due to variations in the routine practice of measuring patients' core temperatures, which may have introduced inconsistencies in our data. The use of forced air warming blankets is recommended to prevent hypothermia and maintain normothermia during perioperative care (51). The findings from the independent t-test with perioperative temperature and the use of forced air blankets indicate that use of forced air blankets is associated with significantly lower body temperatures, suggesting an effective use of hot air blankets to regulate body temperature during surgery. It is important to note, however, that while these blankets are primarily intended to prevent hypothermia, healthcare providers must exercise caution to avoid the possibility of hyperthermia. Proper monitoring and temperature control are crucial to ensure patient safety when using forced air warming blankets. Several other studies have shown perioperative warming to be beneficial in preventing SSIs (8, 52-55). Although we made efforts to ensure the reliability of the data set, there may be an under-reporting of infections that affects our understanding of the extent. It is also important to note that certain surgical procedures may be skewed by age and gender, such as caesarean section among younger women and higher incidence of cholecystitis among women. Physiological changes during pregnancy and the use of regional anaesthesia during caesarean section may also have affected body temperature. It is important to interpret our findings in the light of these limitations.