Obstetric epidural catheter-related infections at a major teaching hospital: a retrospective case series

Infectious complications following regional anesthesia: a narrative review and contemporary estimates of risk

INTRODUCTION

Infectious complications following regional anesthesia (RA) while rare, can be devastating. The objective of this review was to estimate the risk of infectious complications following central neuraxial blocks (CNB) such as epidural anesthesia (EA), spinal anesthesia (SA) and combined spinal epidural (CSE), and peripheral nerve blocks (PNB).

MATERIALS AND METHODS

A literature search was conducted in PubMed, Embase and Cochrane databases to identify reference studies reporting infectious complications in the context of RA subtypes. Both prospective and retrospective studies providing incidence of infectious complications were included for review to provide pooled estimates (with 95% CI). Additionally, we explored incidences specifically associated with spinal anesthesia, incidences of central nervous system (CNS) infections and, the incidences of overall and CNS infections following CNB in obstetric population.

RESULTS

The pooled estimate of overall infectious complications following all CNB was 9/100 000 (95% CI: 5, 13/100 000). CNS infections following all CNB was estimated to be 2/100 000 (95% CI: 1, 3/100 000) and even rarer following SA (1/100 000 (95% CI: 1, 2/100 000)). Obstetric population had a lower rate of overall (1/100 000 (95% CI: 1, 3/100 000)) and CNS infections (4 per million (95% CI: 0.3, 1/100 000)) following all CNB. For PNB catheters, the reported rate of infectious complications was 1.8% (95% CI: 1.2, 2.5/100).

DISCUSSION

Our review suggests that the risk of overall infectious complications following neuraxial anesthesia is very rare and the rate of CNS infections is even rarer. The infectious complications following PNB catheters seems significantly higher compared with CNB. Standardizing nomenclature and better reporting methodologies are needed for the better estimation of the infectious complications.

Construct validation of machine learning for accurately predicting the risk of postoperative surgical site infection following spine surgery

BACKGROUND

This study aimed to evaluate the risk factors for machine learning (ML) algorithms in predicting postoperative surgical site infection (SSI) following spine surgery.

METHODS

This prospective cohort study included 986 patients who underwent spine surgery at Taizhou People's Hospital Affiliated to Nanjing Medical University from January 2015 to October 2022. Supervised ML algorithms included support vector machine, logistic regression, random forest, XGboost, decision tree, k-nearest neighbour, and naïve Bayes (NB), which were tested and trained to develop a predicting model. The ML model performance was evaluated from the test dataset. We gradually analysed their accuracy, sensitivity, and specificity, as well as the positive predictive value, negative predictive value, and area under the curve.

RESULTS

The rate of SSI was 9.33%. Using a backward stepwise approach, we identified that the remarkable risk factors predicting SSI in the multi-variate Cox regression analysis were age, body mass index, smoking, cerebrospinal fluid leakage, drain duration and pre-operative albumin level. Compared with other ML algorithms, the NB model had the highest performance in seven ML models, with an average area under the curve of 0.95, sensitivity of 0.78, specificity of 0.88, and accuracy of 0.87.

CONCLUSIONS

The NB model in the ML algorithm had excellent calibration and accurately predicted the risk of SSI compared with the existing models, and might serve as an important tool for the early detection and treatment of SSI following spinal infection.

The effect of gowning on labor epidural catheter colonization rate: a randomized controlled trial

BACKGROUND

The need to gown for labor epidural catheter insertion is controversial. The American Society of Regional Anesthesia and Pain Medicine has identified a lack of randomized controlled trials investigating this issue. The purpose of this study was to examine the effect of gowning on colonization rates following epidural catheter insertion for labor analgesia.

METHODS

Following research ethics board approval and informed written consent, parturients were randomized to undergo epidural analgesia with the anesthesiologist either ungowned or wearing a sterile gown. Cultures were obtained from each of the operator forearms, the work area under the insertion site, and from the epidural catheter tip as well as from the catheter segment adjacent to the insertion site. The primary outcome was growth of any microbial organisms from the cultured sites.

RESULTS

Two hundred fourteen patients completed the study. There were no significant differences in catheter-tip colonization rates between the ungowned and gowned groups (9.2% vs 7.6%, respectively). The most common microorganism that was cultured was coagulase-negative Staphylococcus.

CONCLUSIONS

The use of gowns in the current study did not affect catheter colonization rate. Overall, there was a relatively high incidence of catheter-tip colonization in both groups, which underscores the need for strict aseptic technique.

Performance of aseptic technique during neuraxial analgesia for labor before and after the publication of international guidelines on aseptic technique

Background

Aseptic technique and handwashing have been shown to be important factors in perioperative bacterial transmission, however compliance often remains low despite guidelines and educational programs. Infectious complications of neuraxial (epidural and spinal) anesthesia are severe but fortunately rare. We conducted a survey to assess aseptic technique practices for neuraxial anesthesia in Israel before and after publication of international guidelines (which focused on handwashing, jewelry/watch removal and the wearing of a mask and cap).

Methods

The sampling frame was the general anesthesiology workforce in hospitals selected from each of the four medical faculties in Israel. Data was collected anonymously over one week in each hospital in two periods: April 2006 and September 2009. Most anesthesiologists received the questionnaires at departmental staff meetings and filled them out during these meetings; additionally, a local investigator approached anesthesiologists not present at these staff meetings individually. Primary endpoint questions were: handwashing, removal of wristwatch/jewelry, wearing mask, wearing hat/cap, wearing sterile gown; answering options were: "always", "usually", "rarely" or "never". Primary endpoint for analysis: respondents who both always wash their hands and always wear a mask ("handwash-mask composite") - "always" versus "any other response". We used logistic regression to perform the analysis. Time (2006, 2009) and hospital were included in the analysis as fixed effects.

Results

135/160 (in 2006) and 127/164 (in 2009) anesthesiologists responded to the surveys; response rate 84% and 77% respectively. Respondents constituted 23% of the national anesthesiologist workforce. The main outcome "handwash-mask composite" was significantly increased after guideline publication (33% vs 58%; p = 0.0003). In addition, significant increases were seen for handwashing (37% vs 63%; p = 0.0004), wearing of mask (61% vs 78%; p < 0.0001), hat/cap (53% vs 76%; p = 0.0011) and wearing sterile gown (32% vs 51%; p < 0.0001). An apparent improvement in aseptic technique from 2006 to 2009 is noted across all hospitals and all physician groups.

Conclusion

Self-reported aseptic technique by Israeli anesthesiologists improved in the survey conducted after the publication of international guidelines. Although the before-after study design cannot prove a cause-effect relationship, it does show an association between the publication of international guidelines and significant improvement in self-reported aseptic technique.

Combined spinal-epidural versus epidural analgesia for labor and delivery

The rapid onset of analgesia and improved mobility with combined spinal-epidural (CSE) techniques has been associated with a higher degree of maternal satisfaction compared with conventional epidural analgesia. However, controversy exists in that initiation of labor analgesia with a CSE may be associated with an increased risk for nonreassuring fetal status (ie, fetal bradycardia) and a subsequent need for emergent cesarean delivery. Overall, both epidural and CSE techniques possess unique risk/benefit profiles, and the decision to use one technique rather than the other should be determined based on individual patient and clinical circumstances.

[Regional anesthesia in patients with pre-existing infections or immunosuppression]

Regional anesthesia is the most effective procedure for acute pain therapy. Whether neuraxial and peripheral blocks in patients with pre-existing infectious conditions, immune deficits or other risk factors increase the risk of additional infections is unclear. Analyzing the available literature currently seems to indicate that the incidence of severe infectious complications is generally low. Diabetes, steroid therapy or malignant diseases are apparently present in many cases in which infections associated with regional anesthesia and analgesia have been described. A strict contraindication in patients with pre-existing systemic or local infections seems unjustifiable. A clear and documented risk-benefit ratio in these patients is mandatory.

Neurological adverse events following regional anesthesia administration

Regional anesthesia and analgesia have been associated with improved analgesia, decreased postoperative nausea and vomiting, and increased patient satisfaction for many types of surgical procedures. In obstetric anesthesia care, it has also been associated with improved maternal mortality and major morbidity. The majority of neurological adverse events following regional anesthesia administration result in temporary sensory symptoms; long-term or permanent disabling motor and sensory problems are very rare. Infection and hemorrhagic complications, particularly with neuraxial blocks, can cause neurological adverse events. More commonly, however, there are no associated secondary factors and some combination of needle trauma, intraneural injection, and/or local anesthetic toxicity may be associated, but their individual contributions to any event are difficult to define.