Systemic Antimicrobial Prophylaxis and Antimicrobial-Coated External Ventricular Drain Catheters for Preventing Ventriculostomy-Related Infections: A Meta-Analysis of 5242 Cases

Surgical and procedural antibiotic prophylaxis in the surgical ICU: an American Association for the Surgery of Trauma Critical Care Committee clinical consensus document

The use of prophylactic measures, including perioperative antibiotics, for the prevention of surgical site infections is a standard of care across surgical specialties. Unfortunately, the routine guidelines used for routine procedures do not always account for many of the factors encountered with urgent/emergent operations and critically ill or high-risk patients. This clinical consensus document created by the American Association for the Surgery of Trauma Critical Care Committee is one of a three-part series and reviews surgical and procedural antibiotic prophylaxis in the surgical intensive care unit. The purpose of this clinical consensus document is to provide practical recommendations, based on expert opinion, to assist intensive care providers with decision-making for surgical prophylaxis. We specifically evaluate the current state of periprocedural antibiotic management of external ventricular drains, orthopedic operations (closed and open fractures, silver dressings, local, antimicrobial adjuncts, spine surgery, subfascial drains), abdominal operations (bowel injury and open abdomen), and bedside procedures (thoracostomy tube, gastrostomy tube, tracheostomy).

Ventriculostomy-associated infection (VAI) in patients with acute brain injury-a retrospective study

BACKGROUND

Ventriculostomy-associated infection (VAI) is common after external ventricular drains (EVD) insertion but is difficult to diagnose in patients with acute brain injury. Previously, we proposed a set of criteria for ruling out VAI in traumatic brain injury. This study aimed to validate these criteria. For exploratory purposes, we sought to develop and validate a score for VAI risk assessment in patients with different types of severe acute brain injury.

METHODS

This retrospective cohort study included adults with acute brain injury who received an EVD and in whom CSF samples were taken over a period of 57 months. As standard non-coated bolt-connected EVDs were used. The predictive performance of biomarkers was analyzed as defined previously. A multivariable regression model was performed with five variables.

RESULTS

A total of 683 patients with acute brain injury underwent EVD placement and had 1272 CSF samples; 92 (13.5%) patients were categorized as culture-positive VAI, 130 (19%) as culture-negative VAI, and 461 (67.5%) as no VAI. A low CSF WBC/RBC ratio (< 0.037), high CSF/plasma glucose ratio (> 0.6), and low CSF protein (< 0.5g/L) showed a positive predictive value of 0.09 (95%CI, 0.05-0.13). In the multivariable logistic regression model, days to sample (OR 1.09; 95%CI, 1.03-1.16) and CSF WBC/RBC ratio (OR 34.86; 95%CI, 3.94-683.15) were found to predict VAI.

CONCLUSION

In patients with acute brain injury and an EVD, our proposed combined cut-off for ruling out VAI performed satisfactorily. Days to sample and CSF WBC/RBC ratio were found independent predictors for VAI in the multivariable logistic regression model.

External Ventricular Drainage: A Practical Guide for Neuro-Anesthesiologists

External ventricular drainage is often considered a life-saving treatment in acute hydrocephalus. Given the large number of discussion points, the ideal management of EVD has not been completely clarified. The objective of this study was to review the most relevant scientific evidence about the management of EVD in its main clinical scenarios. We reviewed the most recent and relevant articles about indications, timing, management, and complications of EVD in neurocritical care, with particular interest in patients with subarachnoid hemorrhage (SAH), severe traumatic brain injury (TBI), and intraventricular hemorrhage (IVH) using the following keywords alone or matching with one another: intracranial pressure, subarachnoid hemorrhage, traumatic brain injury, intraventricular hemorrhage, external ventricular drainage, cerebrospinal shunt, intracranial pressure monitoring, and ventriculoperitoneal shunt. In the management of EVD in SAH, the intermittent drainage strategy is burdened with an elevated risk of complications (e.g., clogged catheter, hemorrhage, and need for replacement). There seems to be more ventriculoperitoneal shunt dependency in rapid weaning approach-managed patients than in those treated with the gradual weaning approach. Although there is no evidence in favor of either strategy, it is conventionally accepted to adopt a continuous drainage approach in TBI patients. Less scientific evidence is available in the literature regarding the management of EVD in patients with severe TBI and intraparenchymal/intraventricular hemorrhage. EVD placement is a necessary treatment in several clinical scenarios. However, further randomized clinical trials are needed to clarify precisely how EVD should be managed in different clinical scenarios.

Risk factors and outcomes associated with external ventricular drain infections

BACKGROUND

Insertion of an external ventricular drain (EVD) is a common neurosurgical procedure which may lead to serious complications including infection. Some risk factors associated with EVD infection are well established. Others remain less certain, including specific indications for placement, prior neurosurgery, and prior EVD placement.

OBJECTIVE

To identify risk factors for EVD infections.

METHODS

We reviewed all EVD insertions at our institution from March 2015 through May 2019 following implementation of a standardized infection control protocol for EVD insertion and maintenance. Cox regression was used to identify risk factors for EVD infections.

RESULTS

479 EVDs placed in 409 patients met inclusion criteria, and 9 culture-positive infections were observed during the study period. The risk of infection within 30 days of EVD placement was 2.2% (2.3 infections/1,000 EVD days). Coagulase-negative staphylococci were identified in 6 of the 9 EVD infections). EVD infection led to prolonged length of stay post-EVD-placement (23 days vs 16 days; P = .045). Cox regression demonstrated increased infection risk in patients with prior brain surgery associated with cerebrospinal fluid (CSF) diversion (HR, 8.08; 95% CI, 1.7-39.4; P = .010), CSF leak around the catheter (HR, 21.0; 95% CI, 7.0-145.1; P = .0007), and insertion site dehiscence (HR, 7.53; 95% CI, 1.04-37.1; P = .0407). Duration of EVD use >7 days was not associated with infection risk (HR, 0.62; 95% CI, 0.07-5.45; P = .669).

CONCLUSION

Risk factors associated with EVD infection include prior brain surgery, CSF leak, and insertion site dehiscence. We found no significant association between infection risk and duration of EVD placement.

Interleukin-6 as a prognostic biomarker of clinical outcomes after traumatic brain injury: a systematic review

Traumatic brain injury (TBI) is a major cause of mortality and morbidity worldwide. There are currently no early biomarkers for prognosis in routine clinical use. Interleukin-6 (IL-6) is a potential biomarker in the context of the established role of neuroinflammation in TBI recovery. Therefore, a systematic review of the literature was performed to assess and summarise the evidence for IL-6 secretion representing a useful biomarker for clinical outcomes. A multi-database literature search between January 1946 and July 2021 was performed. Studies were included if they reported adult TBI patients with IL-6 concentration in serum, cerebrospinal fluid (CSF) and/or brain parenchyma analysed with respect to functional outcome and/or mortality. A synthesis without meta-analysis is reported. Fifteen studies were included, reporting 699 patients. Most patients were male (71.7%), and the pooled mean age was 40.8 years; 78.1% sustained severe TBI. Eleven studies reported IL-6 levels in serum, six in CSF and one in the parenchyma. Five studies on serum demonstrated higher IL-6 concentrations were associated with poorer outcomes, and five showed no signification association. In CSF studies, one found higher IL-6 levels were associated with poorer outcomes, one found them to predict better outcomes and three found no association. Greater parenchymal IL-6 was associated with better outcomes. Despite some inconsistency in findings, it appears that exaggerated IL-6 secretion predicts poor outcomes after TBI. Future efforts require standardisation of IL-6 measurement practices as well as assessment of the importance of IL-6 concentration dynamics with respect to clinical outcomes, ideally within large prospective studies. Prospero registration number: CRD42021271200

Tenets for the Proper Conduct and Use of Meta-Analyses: A Practical Guide for Neurosurgeons

Neurosurgeons today are inundated with rapidly amassing neurosurgical research publications. Systematic reviews and meta-analyses have consequently surged in popularity because, when executed properly, they constitute a high level of evidence and may save busy neurosurgeons many hours of combing and reviewing the literature for relevant articles. Meta-analysis refers to the quantitative (and discretionary) component of systematic reviews. It involves applying statistical techniques to combine effect sizes from multiple studies, which might offer more actionable insights than a systematic review without meta-analysis. Well-executed meta-analyses may prove instructive for clinical practice, but poorly conducted ones sow confusion and have the potential to cause harm. Unfortunately, recent audits have found the conduct and reporting of meta-analyses in neurosurgery (but also other surgical disciplines) to be relatively lackluster in methodologic rigor and compliance to established guidelines. Some of these deficiencies can be easily remedied through better awareness and adherence to prescribed standards-which will be reviewed in this article-but others stem from inherent problems with the source data (e.g., poor reporting of original research) as well as unique constraints faced by surgery as a field (e.g., lack of equipoise for randomized trials, or existence of learning curves for novel surgical procedures, which can lead to temporal heterogeneity), which may require unconventional tools (e.g., cumulative meta-analysis) to address. Therefore, it is also our goal to take stock of the unique issues encountered by surgeons who do meta-analysis and to highlight various techniques-some of which less well-known-to address such challenges.

Antibiotic Prophylaxis and Incidence of Infection with External Ventricular Drains and Intra-Cranial Pressure Monitors

Objectives: Guidelines do not recommend extended antibiotic prophylaxis for external ventricular drains (EVD) or intra-cranial pressure (ICP) monitors. The study objective was to determine if infection rates are different for patients receiving antibiotic prophylaxis for EVD or ICP monitors. Patients and Methods: This single-center retrospective cohort reviewed intensive care unit patients who had an EVD or ICP monitor placed. Patients receiving antibiotic prophylaxis were compared with those who did not receive prophylaxis. The primary end point was incidence of central nervous system (CNS) infection. Results: Overall, 228 patients were included, 120 of whom received prophylaxis and 108 who did not receive prophylaxis. The primary end point of CNS infection was not different between groups (18 [17%] vs. 23 [19%]; p = 0.6236). Conclusions: Antibiotic prophylaxis was not associated with a decreased incidence of CNS infection in patients with EVD or ICP monitors. Evaluation of antibiotic use in this patient population is warranted to prevent resistance and adverse drug effects.

Risk Factors Promoting External Ventricular Drain Infections in Adult Neurosurgical Patients at the Intensive Care Unit-A Retrospective Study

Objectives: Multiple risk factors have been described to be related to external ventricular drain (EVD) associated infections, with results varying between studies. Former studies were limited by a non-uniform definition of EVD associated infection, thus complicating a comparison between studies. In this regard, we assessed risk factors promoting EVD associated infections and propose a modified practice-oriented definition of EVD associated infections.

Methods: We performed a retrospective, single-center study on patients who were treated with an EVD, at the neurosurgical intensive care unit (ICU) at a tertiary center between 2008 and 2019. Based on microbiological findings and laboratory results, patients were assigned into an infection and a non-infection group. Patient characteristics and potential risk factors were compared between the two groups (p < 0.05). Receiver operating characteristics (ROC) for significant clinical, serum laboratory and cerebrospinal fluid (CSF) parameters were calculated.

Results: In total, 396 patients treated with an EVD were included into the study with a mean age of 54.3 (range: 18–89) years. EVD associated infections were observed in 32 (8.1%) patients. EVD insertion at another hospital (OR 3.86), and an increased CSF sampling frequency of more than every third day (OR 12.91) were detected as major risk factors for an EVD associated infection. The indication for EVD insertion, surgeon's experience, the setting of EVD insertion (ICU vs. operating room) and the operating time did not show any significant differences between the two groups. Furthermore, ROC analysis showed that clinical, serum laboratory and CSF parameters did not provide specific prediction of EVD associated infections (specificity 44.4%). This explains the high overtreatment rate in our cohort with the majority of our patients who received intrathecal vancomycin (63.3%), having either negative microbiological results (n = 12) or were defined as contaminations (n = 7).

Conclusions: Since clinical parameters and blood analyzes are not very predictive to detect EVD associated infections in neurosurgical patients, sequential but not too frequent microbiological and laboratory analysis of CSF are still necessary. Furthermore, we propose a uniform classification for EVD associated infections to allow comparability between studies and to sensitize the treating physician in determining the right treatment.

Absence of small study effects in neurosurgical meta-analyses: A meta-epidemiological study

BACKGROUND

Small studies are prone to lower methodological quality and publication bias, and are more likely to report greater beneficial effects. A meta-epidemiological study was undertaken to investigate and quantify the impact of small study effects on meta-analyses in the neurosurgical literature.

METHODS

A PubMed search was used to procure meta-analyses from Journal of Neurosurgery, Neurosurgery, Spine, Acta Neurochirurgica and Journal of Neurotrauma. Outcome data were extracted from meta-analyses the effect of study size was estimated by calculating the ratio of odds ratios (RORs) between small and large studies.

RESULTS

16 meta-analyses of 229 primary studies and 90,629 patients were included. All but two included pooled outcomes were significantly different from 1. On average small studies did not demonstrate greater beneficial effects, with an estimated pooled ROR of 1.32 (95% CI, 0.89 to 1.75). Stratification by meta-analysis effect size and heterogeneity yielded similar findings.

CONCLUSIONS

The absence of small study effects in meta-analyses of neurosurgical studies may reflect widespread poor quality of the neurosurgical literature affecting both large and small studies, rather than an absence of publication bias.

Central nervous system infections associated with neurologic devices

PURPOSE OF REVIEW

To review recent data on the epidemiology, microbiology, diagnosis, and management of central nervous system (CNS) infections associated with neurologic devices.

RECENT FINDINGS

The increasing use of implanted neurologic devices has led to an increase in associated infections. Cerebrospinal fluid (CSF) inflammation may be present after a neurosurgical procedure, complicating the diagnosis of CNS infection. Newer biomarkers such as CSF lactate and procalcitonin show promise in differentiating infection from other causes of CSF inflammation. Molecular diagnostic tests including next-generation or metagenomic sequencing may be superior to culture in identifying pathogens causing healthcare-associated ventriculitis and meningitis.

SUMMARY

Neurologic device infections are serious, often life-threatening complications. Rapid recognition and initiation of antibiotics are critical in decreasing morbidity. Device removal is usually required for cure.

Gram-Negative Ventriculostomy-Associated Infections Predict Shunt Dependency in Stroke Diagnoses and Other Brain Injuries

BACKGROUND

Several predictors have been studied for shunt dependency after stroke and other brain injuries. However, little is known about the association between ventriculostomy-associated infections (VAIs) and impaired cerebrospinal fluid (CSF) outflow. Moreover, gram-negative (GN) VAIs induce a potent neuroinflammatory process and are clinically challenging to treat.

OBJECTIVE

To assess if GN-VAIs predict ventriculoperitoneal shunt (VPS) dependency.

METHODS

Retrospective analysis of postprocedure infection rates was performed in 586 patients with external ventricle drainage (EVD) placed on site between 2012 and 2018. We collected sex, age, stroke and nonstroke related, location of EVD placement, type of hospital, EVD duration, and EVD exchange.

RESULTS

Among 586 patients requiring an EVD, 55 developed a VAI. Most were caused by gram-positive (GP) pathogens (61.8%). A total of 120 patients required a conversion from EVD to VPS. Patients with VAIs had higher rates of VPS placement (49.09% vs 17.65%, P < .001), whereas patients with GN-VAIs had significantly higher rates of EVD conversion to VPS (77.78% vs 35.29%, P = .012) compared with GP-VAIs. The multivariate analysis showed that GN-VAIs were an independent predictor for shunt dependency (odds ratio = 12.896; 95% CI 3.407-48.82, P < .001). In receiver operating characteristics analysis, those less than 44.5 yr of age and more than 12 d of EVD duration were identified as the best cutoff values to discriminate the development of GN-VAI.

CONCLUSION

Patients who experience a GN VAI are in greater risk of impaired CSF outflow, thus requiring VPS placement.

Effectiveness of a Standardized External Ventricular Drain Placement Protocol for Infection Control

INTRODUCTION

Placement of an external ventricular drain (EVD) is a common procedure routinely completed at bedside by neurosurgical residents. A standardized protocol for placement and maintenance of an EVD is potentially useful.

METHODS

This single-institution retrospective review analyzed all patients who underwent placement of an EVD over a 5-year span using a standardized protocol.

RESULTS

A total of 428 EVDs in 381 patients were placed as per this protocol. Overall compliance with the practice protocol was 98.7%. Overall, our infection rate was 1.86% (8 external ventricular drain-related infection [ERIs] over 428 EVDs). There was no difference in age for the ERI cases (median 55, range (50.5-60.5), compared with the non-ERI cases (median of 53, range [38-65]) (P = 0.512). Indications for placement of EVD were hemorrhage (51.9%, n = 198), tumor (16.2%, n = 62), trauma (12.8%, n = 49), hydrocephalus (11.5%, n = 44), cerebellar stroke (2.8%, n = 11), infection (3.1%, n = 12), unknown (1.3%, n = 5). Most EVDs (77.6%, n = 296) were placed bedside by second-year residents (median PGY level 2, interquartile range 1-2.75). Computed tomography confirmed placement in the ipsilateral frontal horn in 72% (n = 277) of EVDs. EVD-related complications were noted in 8.3% of EVDs (n = 32, with 8 infections and 24 tract hemorrhages). The median EVD duration was 10 days; duration of EVD had no statistically significant impact on the risk of an ERI (P = 1). Only replacement of an EVD was associated with an increased risk of infection.

CONCLUSIONS

Adherence to a standard EVD placement protocol is useful in maintaining a low risk of ERI regardless of the duration of catheter utilization. Replacement of the catheter through the same access hole as the original catheter is associated with an increased risk of ERI.

Decreasing External Ventricular Drain Infection Rates in the Neurocritical Care Unit: 12-Year Longitudinal Experience at a Single Institution

OBJECTIVE

External ventricular drain (EVD) placement is a common neurosurgical procedure, and EVD-related infection is a significant complication. We examined the effect of infection control protocol changes on EVD-related infection incidence.

METHODS

Changes in EVD placement protocol and incidence density of infections after implementation of protocol changes in the neurocritical care unit were tracked from 2007 to 2019. EVD infections were defined using a modified U.S. Centers for Disease Control and Prevention National Healthcare Safety Network surveillance definition of meningitis/ventriculitis for patients with EVDs in situ for at least 2 days confirmed by positive culture. Contribution of protocol changes to EVD infection risk was assessed via multivariate regression.

RESULTS

Fifteen major changes in EVD protocol were associated with a reduction in infections from 6.7 to 2.0 per 1000 EVD days (95% confidence interval [CI], 4.1-5.3; P < 0.001). Gram-positive bacterial infection incidence decreased from 4.8 to 1.7 per 1000 EVD days (95% CI, 2.3-3.9; P = 0.00882) and gram-negative infection incidence decreased from 1.9 to 0.5 per 1000 EVD days (95% CI, 0.6-2.3; P = 0.0303). Of all protocol changes since 2007, the largest reduction in incidence was 3.9 infections per 1000 days (95% CI, 0.50-7.30; P = 0.011), associated with combined standardization of reduced EVD sampling frequency, cutaneous antisepsis with alcoholic chlorhexidine before EVD placement, and use of a subcutaneous tunneling technique during EVD insertion.

CONCLUSIONS

The most significant reduction in EVD infections may be achieved through the combination of reducing EVD sampling frequency and standardizing alcoholic chlorhexidine cutaneous antisepsis and subcutaneous tunneling of the EVD catheter.

The Evolution of the Role of External Ventricular Drainage in Traumatic Brain Injury

External ventricular drains (EVDs) are commonly used in neurosurgery in different conditions but frequently in the management of traumatic brain injury (TBI) to monitor and/or control intracranial pressure (ICP) by diverting cerebrospinal fluid (CSF). Their clinical effectiveness, when used as a therapeutic ICP-lowering procedure in contemporary practice, remains unclear. No consensus has been reached regarding the drainage strategy and optimal timing of insertion. We review the literature on EVDs in the setting of TBI, discussing its clinical indications, surgical technique, complications, clinical outcomes, and economic considerations.