Factors influencing the risk of surgical site infection following diagnostic exploration of the abdominal cavity

Profiles of central nervous system surgical site infections in endoscopic transnasal surgery exposing the intradural space

OBJECTIVE

Despite its efficacy and minimal invasiveness, the clean-contaminated nature of endoscopic transnasal surgery (ETS) may be susceptible to central nervous system surgical site infections (CNS-SSIs), especially when involving intradural exposure. However, the profiles of ETS-associated CNS-SSIs are not fully elucidated.

METHODS

The institutional ETS cases performed between May 2017 and March 2023 were retrospectively analysed. The incidences of CNS-SSIs were calculated, and their risk factors examined.

RESULTS

The incidence of CNS-SSIs was 2.3% (7/305) in the entire cohort and 5.0% (7/140) in ETSs with intradural exposure. All the CNS-SSIs were meningitis and developed following ETS with intradural exposure. The incidences were 0%, 5.6% and 5.8% in ETSs with Esposito grade 1, 2 and 3 intraoperative cerebrospinal fluid leakage, respectively. Among the pre- and intra-operative factors, body mass index (unit odds ratio (OR), 0.62; 95% confidence interval (CI), 0.44-0.89; P<0.01), serum albumin (unit OR, 0.03; 95% CI, 0.0007-0.92; P=0.02), and American Society of Anesthesiologists physical status score (unit OR, 20.7; 95% CI, 1.65-259; P<0.01) were significantly associated with CNS-SSIs. Moreover, postoperative cerebrospinal fluid leakage was also significantly associated with CNS-SSIs (OR, 18.4; 95% CI, 3.55-95.0; P<0.01).

CONCLUSIONS

The incidence of ETS-associated CNS-SSIs is acceptably low. Intradural exposure was a prerequisite for CNS-SSIs. Malnutrition and poor comorbidity status should be recognized as important risks for CNS-SSIs in ETS.

The detection and prediction of surgical site infections using multi-modal sensors and machine learning: Results in an animal model

Introduction

Surgical Site Infection (SSI) is a common healthcare-associated infection that imposes a considerable clinical and economic burden on healthcare systems. Advances in wearable sensors and digital technologies have unlocked the potential for the early detection and diagnosis of SSI, which can help reduce this healthcare burden and lower SSI-associated mortality rates.

Methods

In this study, we evaluated the ability of a multi-modal bio-signal system to predict current and developing superficial incisional infection in a porcine model infected with Methicillin Susceptible Staphylococcus Aureus (MSSA) using a bagged, stacked, and balanced ensemble logistic regression machine learning model.

Results

Results demonstrated that the expression levels of individual biomarkers (i.e., peri-wound tissue oxygen saturation, temperature, and bioimpedance) differed between non-infected and infected wounds across the study period, with cross-correlation analysis indicating that a change in bio-signal expression occurred 24 to 31 hours before this change was reflected by clinical wound scoring methods employed by trained veterinarians. Moreover, the multi-modal ensemble model indicated acceptable discriminability to detect the presence of a current superficial incisional SSI (AUC = 0.77), to predict an SSI 24 hours in advance of veterinarian-based SSI diagnosis (AUC = 0.80), and to predict an SSI 48 hours in advance of veterinarian-based SSI diagnosis (AUC = 0.74).

Discussion

In sum, the results of the current study indicate that non-invasive multi-modal sensor and signal analysis systems have the potential to detect and predict superficial incisional SSIs in porcine subjects under experimental conditions.

Laparoscopy Compared With Laparotomy for the Management of Pediatric Blunt Abdominal Trauma

BACKGROUND

There is minimal evidence evaluating the risks and benefits of laparoscopy use in hemodynamically stable children with suspected abdominal injuries. The objective of this study was to evaluate postoperative outcomes in a large cohort of hemodynamically stable pediatric patients with blunt abdominal injury.

METHODS

Using the 2015-2016 National Trauma Data Bank, all patients aged <18 y with injury severity score (ISS) ≤25, Glasgow coma scale ≥13, and normal blood pressure who underwent an abdominal operation for blunt abdominal trauma were included. Patients were grouped into three treatment groups: laparotomy, laparoscopy, and laparoscopy converted to laparotomy. Treatment effect estimation with inverse probability weighting was used to determine the association between treatment group and outcomes of interest.

RESULTS

Of 720 patients, 504 underwent laparotomy, 132 underwent laparoscopy, and 84 underwent laparoscopy converted to laparotomy. The median age was 10 (IQR: 7-15) y, and the median ISS was 9 (IQR: 5-14). Mean hospital length of stay was 2.1 d shorter (95% confidence interval [CI]: 0.9-3.2 d) and mean intensive care unit length of stay was 1.1 d shorter (95% CI: 0.6-1.5 d) for the laparoscopy group compared with the laparotomy group. The laparoscopy group had a 2.0% lower mean probability of surgical site infection than the laparotomy group (95% CI: 1.0%-3.0%).

CONCLUSIONS

In this cohort of hemodynamically stable pediatric patients with blunt abdominal injury, laparoscopy may have improved outcomes over laparotomy.

Prolonged Operative Duration Increases Risk of Surgical Site Infections: A Systematic Review

Background: The incidence of surgical site infection (SSI) across surgical procedures, specialties, and conditions is reported to vary from 0.1% to 50%. Operative duration is often cited as an independent and potentially modifiable risk factor for SSI. The objective of this systematic review was to provide an in-depth understanding of the relation between operating time and SSI.

Patients and Methods: This review included 81 prospective and retrospective studies. Along with study design, likelihood of SSI, mean operative times, time thresholds, effect measures, confidence intervals, and p values were extracted. Three meta-analyses were conducted, whereby odds ratios were pooled by hourly operative time thresholds, increments of increasing operative time, and surgical specialty.

Results: Pooled analyses demonstrated that the association between extended operative time and SSI typically remained statistically significant, with close to twice the likelihood of SSI observed across various time thresholds. The likelihood of SSI increased with increasing time increments; for example, a 13%, 17%, and 37% increased likelihood for every 15 min, 30 min, and 60 min of surgery, respectively. On average, across various procedures, the mean operative time was approximately 30 min longer in patients with SSIs compared with those patients without.

Conclusions: Prolonged operative time can increase the risk of SSI. Given the importance of SSIs on patient outcomes and health care economics, hospitals should focus efforts to reduce operative time.

A prospective randomized controlled trial of subcutaneous passive drainage for the prevention of superficial surgical site infections in open and laparoscopic colorectal surgery

INTRODUCTION

A number of studies have evaluated the effects of subcutaneous drainage during digestive surgery. All of the previous studies assessed the usefulness of active-suctioning drain, including two randomized controlled studies which found no benefit for the placement of active-suctioning drains in digestive surgery. The utility of passive drainage has not been evaluated previously. The purpose of this study was to evaluate the efficacy of subcutaneous passive drainage system for preventing surgical site infections during major colorectal surgery.

PATIENTS AND METHODS

A total of 263 patients who underwent major colorectal surgery were enrolled in this study. Patients were randomly assigned to receive subcutaneous passive drainage or no drainage. The primary outcome measured was the incidence of superficial surgical site infections. The secondary outcomes measured were the development of hematomas, seromas, and wound dehiscence.

RESULTS

Finally, a total of 246 patients (124 underwent passive drainage, and 122 underwent no drainage) were included in the analysis after randomization. There was a significant difference in the incidence of superficial surgical site infections between patients assigned to the passive drainage and no drainage groups (3.2 % vs 9.8 %, respectively, P = 0.041). There were no cases that developed a hematoma, seroma, or wound dehiscence in either group. A subgroup analysis revealed that male gender, age ≥75 years, diabetes mellitus, American Society of Anesthesiologists (ASA) status ≥2, blood loss ≥100 ml, and open access were factors that were associated with a beneficial effect of subcutaneous passive drainage.

CONCLUSIONS

Subcutaneous passive drainage provides benefits over no drainage in patients undergoing major colorectal surgery.

Gender differences in risk of bloodstream and surgical site infections

BACKGROUND

Identifying patients most at risk for hospital- and community-associated infections is one essential strategy for preventing infections.

OBJECTIVE

To investigate whether rates of community- and healthcare-associated bloodstream and surgical site infections varied by patient gender in a large cohort after controlling for a wide variety of possible confounders.

DESIGN

Retrospective cohort study.

PARTICIPANTS

All patients discharged from January 1, 2006 through December 31, 2008 (133,756 adult discharges and 66,592 pediatric discharges) from a 650-bed tertiary care hospital, a 220-bed community hospital, and a 280-bed pediatric acute care hospital within a large, academic medical center in New York, NY.

MAIN MEASURES

Data were collected retrospectively from various electronic sources shared by the hospitals and linked using patients' unique medical record numbers. Infections were identified using previously validated computerized algorithms.

KEY RESULTS

Odds of community-associated bloodstream infections, healthcare-associated bloodstream infections, and surgical site infections were significantly lower for women than for men after controlling for present-on-admission patient characteristics and events during the hospital stay [odds ratios (95 % confidence intervals) were 0.85 (0.77-0.93), 0.82 (0.74-0.91), and 0.78 (0.68-0.91), respectively]. Gender differences were greatest for older adolescents (12-17 years) and adults 18-49 years and least for young children (<12 years) and older adults (≥ 70 years).

CONCLUSIONS

In this cohort, men were at higher risk for bloodstream and surgical site infections, possibly due to differences in propensity for skin colonization or other anatomical differences.

Performance, revision, and extension of the National Nosocomial Infections Surveillance system's risk index in Brazilian hospitals

OBJECTIVE

To assess the benefit of using procedure-specific alternative cutoff points for National Nosocomial Infections Surveillance (NNIS) risk index variables and of extending surgical site infection (SSI) risk prediction models with a postdischarge surveillance indicator.

DESIGN

Open, retrospective, validation cohort study.

SETTING

Five private, nonuniversity Brazilian hospitals.

PATIENTS

Consecutive inpatients operated on between January 1993 and May 2006 (other operations of the genitourinary system [n = 20,723], integumentary system [n = 12,408], or musculoskeletal system [n = 15,714] and abdominal hysterectomy [n = 11,847]).

METHODS

For each procedure category, development and validation samples were defined nonrandomly. In the development samples, alternative SSI prognostic scores were constructed using logistic regression: (i) alternative NNIS scores used NNIS risk index covariates and cutoff points but locally derived SSI risk strata and rates, (ii) revised scores used procedure-specific alternative cutoff points, and (iii) extended scores expanded revised scores with a postdischarge surveillance indicator. Performances were compared in the validation samples using calibration, discrimination, and overall performance measures.

RESULTS

The NNIS risk index showed low discrimination, inadequate calibration, and predictions with high variability. The most consistent advantage of alternative NNIS scores was regarding calibration (prevalence and dispersion components). Revised scores performed slightly better than the NNIS risk index for most procedures and measures, mainly in calibration. Extended scores clearly performed better than the NNIS risk index, irrespective of the measure or operative procedure.

CONCLUSIONS

Locally derived SSI risk strata and rates improved the NNIS risk index's calibration. Alternative cutoff points further improved the specification of the intrinsic SSI risk component. Controlling for incomplete postdischarge SSI surveillance provided consistently more accurate SSI risk adjustment.

Rates of surgical site infection as a performance measure: Are we ready?

With the introduction of quality assurance in health care delivery, there has been a proliferation of research studies that compare patient outcomes for similar conditions among many health care delivery facilities. Since the 1990s, increasing interest has been placed in the incorporation of clinical adverse events as quality indicators in hospital quality assurance programs. Adverse post-operative events, and very especially surgical site infection (SSI) rates after specific procedures, gained popularity as hospital quality indicators in the 1980s. For a SSI rate to be considered a valid indicator of the quality of care, it is essential that a proper adjustment for patient case mix be performed, so that meaningful comparisons of SSI rates can be made among surgeons, institutions, or over time. So far, a significant impediment to developing meaningful hospital-acquired infection rates that can be used for intra- and inter-hospital comparisons has been the lack of an adequate means of adjusting for case mix. This paper discusses what we have learned in the last years regarding risk adjustment of SSI rates for provider performance assessment, and identifies areas in which significant improvement is still needed.

Accounting for incomplete postdischarge follow-up during surveillance of surgical site infection by use of the National Nosocomial Infections Surveillance system's risk index

OBJECTIVE

We examined the usefulness of a simple method to account for incomplete postdischarge follow-up during surveillance of surgical site infection (SSI) by use of the National Nosocomial Infections Surveillance (NNIS) system's risk index.

DESIGN

Retrospective cohort study that used data prospectively collected from 1993 through 2006.

SETTING

Five private, nonuniversity healthcare facilities in Belo Horizonte, Brazil.

PATIENTS

Consecutive patients undergoing the following NNIS operative procedures: 20,981 operations on the genitourinary system, 11,930 abdominal hysterectomies, 7,696 herniorraphies, 6,002 cholecystectomies, and 6,892 laparotomies.

METHODS

For each operative procedure category, 2 SSI risk models were specified. First, a model based on the NNIS system's risk index variables was specified (hereafter referred to as the NNIS-based model). Second, a modified model (hereafter referred to as the modified NNIS-based model), which was also based on the NNIS system's risk index, was specified with a postdischarge surveillance indicator, which was assigned the value of 1 if the patient could be reached during follow-up and a value of 0 if the patient could not be reached. A formal comparison of the capabilities of the 2 models to assess the risk of SSI was conducted using measures of calibration (by use of the Pearson goodness-of-fit test) and discrimination (by use of receiver operating characteristic curves). Goodman-Kruskal correlations (G) were also calculated.

RESULTS

The rate of incomplete postdischarge follow-up varied between 29.8% for abdominal hysterectomies and 50.5% for cholecystectomies. The modified NNIS-based model for laparotomy did not show any significant benefit over the NNIS-based model in any measure. For all other operative procedures, the modified NNIS-based model showed a significantly improved discriminatory ability and higher G statistics, compared with the NNIS-based model, with no significant impairment in calibration, except if used to assess the risk of SSI after operations on the genitourinary system or after a cholecystectomy.

CONCLUSIONS

Compared with the NNIS-based model, the modified NNIS-based model added potentially useful clinical information regarding most of the operative procedures. Further work is warranted to evaluate this method for accounting for incomplete postdischarge follow-up during surveillance of SSI.

Laparoscope use and surgical site infections in digestive surgery

OBJECTIVE

To compare surgical site infection (SSI) rates in open or laparoscopic appendectomy, cholecystectomy, and colon surgery. To investigate the effect of laparoscopy on SSI in these interventions.

BACKGROUND

Lower rates of SSI have been reported among various advantages associated with laparoscopy when compared with open surgery, particularly in cholecystectomy. However, biases such as the lack of postdischarge follow-up and confounding factors might have contributed to the observed differences between the 2 techniques.

METHODS

This observational study was based on prospectively collected data from an SSI surveillance program in 8 Swiss hospitals between March 1998 and December 2004, including a standardized postdischarge follow-up. SSI rates were compared between laparoscopic and open interventions. Factors associated with SSI were identified by using logistic regression models to adjust for potential confounding factors.

RESULTS

SSI rates in laparoscopic and open interventions were respectively 59/1051 (5.6%) versus 117/1417 (8.3%) in appendectomy (P = 0.01), 46/2606 (1.7%) versus 35/444 (7.9%) in cholecystectomy (P < 0.0001), and 35/311 (11.3%) versus 400/1781 (22.5%) in colon surgery (P < 0.0001). After adjustment, laparoscopic interventions were associated with a decreased risk for SSI: OR = 0.61 (95% CI 0.43-0.87) in appendectomy, 0.27 (0.16-0.43) in cholecystectomy, and 0.43 (0.29-0.63) in colon surgery. The observed effect of laparoscopic techniques was due to a reduction in the rates of incisional infections, rather than in those of organ/space infections.

CONCLUSION

When feasible, a laparoscopic approach should be preferred over open surgery to lower the risks of SSI.