Central Venous Catheterization: Better and Worse

Quantitative assessment of reflux in commercially available needle-free IV connectors

INTRODUCTION

Blood reflux is caused by changes in pressure within intravascular catheters upon connection or disconnection of a syringe or intravenous tubing from a needle-free connector (NFC). Changes in pressure, differing with each brand of NFC, may result in fluid movement and blood reflux that can contribute to intraluminal catheter occlusions and increase the potential for central-line associated bloodstream infections (CLABSI).

METHODS

In this study, 14 NFC brands representing each of the four market-categories of NFCs were selected for evaluation of fluid movement occurring during connection and disconnection of a syringe. Study objectives were to 1) theoretically estimate amount of blood reflux volume in microliters (μL) permitted by each NFC based on exact component measurements, and 2) experimentally measure NFC volume of fluid movement for disconnection reflux of negative, neutral and anti-reflux NFC and fluid movement for connection reflux of positive displacement NFC.

RESULTS

The results demonstrated fluid movement/reflux volumes of 9.73 μL to 50.34 μL for negative displacement, 3.60 μL to 10.80 μL for neutral displacement, and 0.02 μL to 1.73 μL for pressure-activated anti-reflux NFC. Separate experiment was performed measuring connection reflux of 18.23 μL to 38.83 μL for positive displacement NFC connectors.

CONCLUSIONS

This study revealed significant differences in reflux volumes for fluid displacement based on NFC design. While more research is needed on effects of blood reflux in catheters and NFCs, results highlight the need to consider NFCs based on performance of individual connector designs, rather than manufacturer designation of positive, negative and neutral marketing categories for NFCs without anti-reflux mechanisms.

Evidence-based consensus on the insertion of central venous access devices: definition of minimal requirements for training

There is a lack of standard minimal requirements for the training of insertion techniques and maintenance of central venous access devices (CVADs). An international evidence-based consensus task force was established through the World Congress of Vascular Access (WoCoVA) to provide definitions and recommendations for training and insertion of CVADs. Medical literature published from February 1971 to April 2012 regarding 'central vascular access', 'training', 'competency', 'simulation', and 'ultrasound' was reviewed on Pubmed, BioMed Central, ScienceDirect, and Scopus databases. The GRADE and the GRADE-RAND methods were utilized to develop recommendations. Out of 156 papers initially identified, 83 papers described training for central vascular access placement. Sixteen recommendations are proposed by this task force, each with an evidence level, degree of consensus, and recommendation grade. These recommendations suggest central venous access education include didactic or web-based teaching with insertion procedure, infection prevention, complications, care, and maintenance of devices, along with laboratory models and tools for simulation practice incorporating ultrasound. Clinical competence should be determined by observation during clinical practice using a global rating scale rather than by the number of procedures performed. Ensuring safe insertion and management of central venous devices requires standardized education, simulation practice, and supervised insertions.

Use of simulation-based mastery learning to improve the quality of central venous catheter placement in a medical intensive care unit

BACKGROUND

Central venous catheter (CVC) insertions are performed frequently by internal medicine residents. Complications, including arterial puncture and pneumothorax, decrease when operators use fewer needle passes to insert the CVC. In this study, we evaluated the effect of simulation-based mastery learning on CVC insertion skill.

DESIGN

This was a cohort study of internal jugular (IJ) and subclavian (SC) CVC insertions by 41 internal medicine residents rotating through the medical intensive care unit (MICU) over a five-month period. Thirteen traditionally-trained residents were surveyed about the number of needle passes, complications, and procedural self-confidence on CVCs inserted in the MICU. Concurrently, 28 residents completed simulation-based training in IJ and SC CVC insertions. Simulator-trained residents were expected to perform CVC insertions to mastery standards on a central line simulator. Simulator-trained residents then rotated through the MICU and were surveyed regarding CVC placement. The impact of simulation training was assessed by comparing group survey results.

RESULTS

No resident met the minimum passing score (MPS) (79.1%) for CVC insertion at baseline: mean (M) (IJ) = 48.4%, standard deviation (SD) = 23.1, M(SC) = 45.2%, SD = 26.3. All residents met or exceeded the MPS at testing after simulation training: M(IJ) = 94.8%, SD = 10.0, M(SC) = 91.1%, SD = 17.8 (p < 0.001). In the MICU, simulator-trained residents required fewer needle passes to insert a CVC than traditionally-trained residents: M = 1.79, SD = 1.0 versus M = 2.78, SD = 1.77 (p = 0.04). Simulator-trained residents displayed more self-confidence about their procedural skills: (M = 81, SD = 11 versus M = 68, SD = 20, p = 0.02).

CONCLUSIONS

Simulation-based mastery learning increased residents' skills in simulated CVC insertion, decreased the number of needle passes when performing actual procedures, and increased resident self-confidence.

Improving quality and patient safety by minimizing unnecessary variation

Quality and safety in health care have proven difficult to precisely define and measure. In other fields, quality is defined as the absence of unnecessary variation and process improvement efforts are gauged by their ability to reduce variation. This article explores how this definition can be applied to various attributes of image-guided procedures.

Ultrasound-guided interventional radiology in critical care

Ultrasound-guided intervention is becoming an increasingly popular and valuable tool in the critical care setting. In general, image-guided procedures can expedite wait times and increase the accuracy, safety, and efficacy of many procedures commonly performed within intensive care units. In the intensive care unit setting, ultrasound has particular advantages over other imaging modalities such as computed tomography and fluoroscopy, including real-time visualization, portability permitting bedside procedures, and reduced exposure to nephrotoxic contrast agents. We review the technical and procedural aspects of a number of ultrasound-guided interventions appropriate for critical care patients. These include central venous catheter deployment, thoracentesis, paracentesis, and drainage of a wide variety of abscesses, and percutaneous nephrostomy, percutaneous cholecystectomy, and inferior vena cava filter placement. Although we believe ultrasound is significantly underutilized in critical care today, we anticipate that with the improvement of ultrasound technology and the innovation of new ultrasound-guided procedures, the role of ultrasound in the intensive care unit will continue to expand, with bedside ultrasound-guided interventions increasingly becoming the norm.