Effectiveness of different central venous catheter fixation suture techniques: An in vitro crossover study.

PURPOSE: Proper fixation of central venous catheters (CVCs) is an integral part of safety to avoid dislodgement and malfunction. However, the effectiveness of different CVC securement sutures is unknown. METHODS: Analysis of maximum dislodgement forces for CVCs from three different manufacturers using four different suture techniques in an in vitro tensile loading experiment: 1. "clamp only", 2. "clamp and compression suture", 3. "finger trap" and 4. "complete", i.e., "clamp + compression suture + finger trap". Twenty-five tests were performed for each of the three CVC models and four securement suture techniques (n = 300 test runs). RESULTS: The primary cause of catheter dislodgement was sliding through the clamp in techniques 1 and 2. In contrast, rupture of the suture was the predominant cause for dislodgement in techniques 2 and 3. Median (IQR 25-75%) dislodgement forces were 26.0 (16.6) N in technique 1, 26.5 (18.8) N in technique 2, 76.7 (18.7) N in technique 3, and 84.8 (11.8) N in technique 4. Post-hoc analysis demonstrated significant differences (P < .001) between all pairwise combinations of techniques except technique 1 vs. 2 (P = .98). CONCLUSIONS: "Finger trap" fixation at the segmentation site considerably increases forces required for dislodgement compared to clamp-based approaches.

Central venous catheterization for acute trauma resuscitation: Tip position analysis using routine emergency computed tomography.

PURPOSE: Central venous catheter insertion for acute trauma resuscitation may be associated with mechanical complications, but studies on the exact central venous catheter tip positions are not available. The goal of the study was to analyze central venous catheter tip positions using routine emergency computed tomography. METHODS: Consecutive acute multiple trauma patients requiring large-bore thoracocervical central venous catheters in the resuscitation room of a university hospital were enrolled retrospectively from 2010 to 2015. Patients who received a routine emergency chest computed tomography were analyzed regarding central venous catheter tip position. The central venous catheter tip position was defined as correct if the catheter tip was placed less than 1 cm inside the right atrium relative to the cavoatrial junction, and the simultaneous angle of the central venous catheter tip compared with the lateral border of the superior vena cava was below 40°. RESULTS: During the 6-year study period, 97 patients were analyzed for the central venous catheter tip position in computed tomography. Malpositions were observed in 29 patients (29.9%). Patients with malpositioned central venous catheters presented with a higher rate of shock (systolic blood pressure <90 mmHg) at admission (58.6% vs 33.8%, p = 0.023) and a higher mean injury severity score (38.5 ± 15.7 vs 31.6 ± 11.8, p = 0.041) compared with patients with correctly positioned central venous catheter tips. Logistic regression revealed injury severity score as a significant predictor for central venous catheter malposition (odds ratio = 1.039, 95% confidence interval = 1.005-1.074, p = 0.024). CONCLUSION: Multiple trauma patients who underwent emergency central venous catheter placement by experienced anesthetists presented with considerable tip malposition in computed tomography, which was significantly associated with a higher injury severity.

Central venous catheter tip migration due to tracheal extubation: a prospective randomized study.

Considerable numbers of patients undergo central venous catheterization (CVC) under mechanical ventilation. We hypothesized that the return of spontaneous breathing and tracheal extubation could be associated with distal CVC tip migration towards intracardiac positions due to decreasing intrathoracic pressures and subsequent readjustment of mediastinal organs. Patients scheduled for cardiac surgery were randomized for right or left internal jugular vein (IJV) CVC placement under general anesthesia and mechanical ventilation. CVC tips were positioned at the cavoatrial junction and measured at the time of placement, postoperatively under mechanical ventilation, and after tracheal extubation until 48 h after surgery. Measurement methods included intravascular electrocardiography (ECG) P-wave amplitude, transesophageal echocardiography, and chest radiography (CXR). Out of 70 patients, 60 were eligible for final statistical analysis (31 right and 29 left IJV CVC). According to ECG interpretation, CVC tip positions remained below the pericardiac reflection point in the distal superior vena cava over the course of the three measurement intervals. The ECG revealed significant proximal migration of CVC tips from the time of placement to the time of tracheal extubation (1.19 ± 0.55 vs. 0.62 ± 0.31 mV; P < 0.001). A CXR using CVC tip to carina distances revealed no significant tip migrations in the time between postoperative assessment and following tracheal extubation (5.1 ± 1.7 vs. 5.3 ± 1.5 cm; P = 0.196). In patients with CVCs positioned at the cavoatrial junction, tracheal extubation was not associated with significant postoperative CVC tip malposition, but tended to undergo proximal migration. This trend should be considered particularly in left-sided thoracocervical puncture approaches to avoid unfavorable CVC tip positions.

Formulas for prediction of insertion depths of internal jugular vein catheters adjusted to body height categories.

PURPOSE: Whether formulas for prediction of central venous catheter (CVC) insertion depths have different applicability in patients with different body heights is not known. Goal of study was to test formulas for catheterizations of internal jugular veins (IJVs) in a population of different body height classes with correct CVC tip positions. METHODS: Consecutive adult patients requiring CVC for cardiac surgery were enrolled and those with tip positions at the junction of the superior vena cava and the right atrium ±1 cm underwent formula analysis. Precision of formula prediction was calculated for three classes of body height. RESULTS: Of the 635 included patients, 254 underwent right IJV catheterization and 381 underwent left IJV catheterization, respectively. Formula-guided approach for both right [formulas (height/10) (in cm) and (height/10) -1 (in cm)] and left [formula (height/10) + 4 (in cm)] IJV CVC was more precise in patients with a body height of 170-180 cm compared with patients with a body height <170 cm (who required deeper insertion than predicted by formula) and patients with a body height >180 cm (who required a more proximal insertion than predicted by formula). CONCLUSIONS: Independent from body height classes, all formulas calculated a relatively low likelihood of atrial positions but high risks of proximal mal-positioning. Thus, considering inter-individual differences of vascular anatomy and for safety reasons, formulas cannot be recommended.

Different mechanical properties in Seldinger guide wires.

BACKGROUND AND AIMS: Most central venous catheters are placed using Seldinger guide wires. EN ISO 11070 is the guideline for testing guide wire flexing performance and tensile strength, and we can safely assume that guide wires in use meet these requirements. Unfortunately, EN ISO 11070 guidelines do not reflect the clinical requirements and we continue to see mechanical failures and their associated complications. MATERIAL AND METHODS: This in vitro study was performed in an accredited laboratory. With regard to flexing, we: (1) Established the minimum flexing performance needed to meet clinical requirements, (2) developed flexing performance tests which mimic clinical requirement, and (3) evaluated the mechanical properties of various guide wires relative to these requirements. With regard to tensile strength, we used the testing method prescribed in ISO 11070, but did not end the test at 5 Newton (N). We continued until the guide wire was damaged, or we reached maximum tractive force. We then did a wire-to-wire comparison. We examined two basic wire constructions, monofil and core and coil. RESULTS: Tensile strength: All wires tested, except one, met EN ISO 11070 requirements for 5 N tensile strength. The mean of the wire types tested ranged from 15.06 N to 257.76 N. Flexing performance: None of the wires kinked. The monofil had no evidence of bending. Two core/coil wires displayed minor bending (angle 1.5°). All other wires displayed bending angles between 22.5° and 43.0°. CONCLUSION: We recommend that: (1) Clinicians use guide wires with high-end mechanical properties, (2) EN ISO 11070 incorporate our flexing test into their testing method, raise the flexing requirement to kink-proof, (3) and raise the tensile strength requirement to a minimum of 30 N, and (3) all manufacturers and suppliers be required to display mechanical properties of all guide wire, and guide wire kits sold.

Mechanical properties of Seldinger guidewires.

BACKGROUND: Almost all central venous catheters are placed using the Seldinger technique. Despite the introduction of ISO 11070 in 1998, we continue to see mechanical wire failures and their associated complications. METHODS: Seven different wire types were tested regarding their tensile strength and eight different types for their flexing performance. For each wire type six wires were assessed. Tensile strength was examined using the test method described in ISO 11070, but the test did not end at 10 N. For flexing performance testing a new apparatus, closely mimicking clinical requirements, was designed.Wires were scanned digitally after testing for measurement and analysis. RESULTS: All wire types tested, except one, consistently met ISO 11070 requirements for 10 N tensile strength. The maximum tension the wires were able to withstand ranged from 15.06 N to 257.76 N.None of the wires kinked. The monofil wires had no evidence of bending. Two core and coil wires displayed minor bending (angle 1.5°). All other wires displayed bending angles between 22.5° and 43.0°. The degree of bending was also dependent on the angle between the dilator and wire. CONCLUSION: The mechanical properties of different types of guidewires show considerable differences, not detected with current ISO 11070 based testing. Uncovering those may allow set up of clinical trials to examine whether regular use of wires with high-end mechanical properties could reduce CVC insertion-related complication rates.

International evidence-based recommendations on ultrasound-guided vascular access.

PURPOSE: To provide clinicians with an evidence-based overview of all topics related to ultrasound vascular access. METHODS: An international evidence-based consensus provided definitions and recommendations. Medical literature on ultrasound vascular access was reviewed from January 1985 to October 2010. The GRADE and the GRADE-RAND methods were utilised to develop recommendations. RESULTS: The recommendations following the conference suggest the advantage of 2D vascular screening prior to cannulation and that real-time ultrasound needle guidance with an in-plane/long-axis technique optimises the probability of needle placement. Ultrasound guidance can be used not only for central venous cannulation but also in peripheral and arterial cannulation. Ultrasound can be used in order to check for immediate and life-threatening complications as well as the catheter's tip position. Educational courses and training are required to achieve competence and minimal skills when cannulation is performed with ultrasound guidance. A recommendation to create an ultrasound curriculum on vascular access is proposed. This technique allows the reduction of infectious and mechanical complications. CONCLUSIONS: These definitions and recommendations based on a critical evidence review and expert consensus are proposed to assist clinicians in ultrasound-guided vascular access and as a reference for future clinical research.

Prospective clinical evaluation of a new manometer syringe that distinguishes pressures below 30 and above 50 mmHg.

STUDY OBJECTIVE: To evaluate a new disposable syringe (Certofix PresSure Check [B Braun Melsungen AG, Melsungen, Germany]) that serves as a manometer. DESIGN: Prospective study. SETTING: University hospital's cardiac surgery suite. PATIENTS: 21 consecutive patients with continuous invasive monitoring of central venous and arterial pressures during cardiothoracic surgery. INTERVENTIONS AND MEASUREMENTS: The Certofix PresSure Check syringe was connected to the side port of the central venous and arterial catheters. RESULTS: Central venous pressures were correctly indicated as below 30 mmHg and arterial pressures as above 50 mmHg in all 21 patients. CONCLUSIONS: Certofix PresSure Check provides a unique way of testing whether a catheter is placed in a low or high pressure system. It can be used for identifying inadvertent arterial punctures.

Is traditional reading of the bedside chest radiograph appropriate to detect intraatrial central venous catheter position?

BACKGROUND: Traditionally, the positioning of central venous catheters (CVCs) outside the right atrium (RA) in patients receiving intensive care is determined by surrogate landmarks on bedside chest radiographs (CXRs). The validity of this method was examined by comparing readings of radiologists with the results of transesophageal echocardiography (TEE). METHODS: Prospective study at university hospital. Two hundred thirteen adults scheduled for cardiothoracic surgery were randomized to right or left internal jugular vein catheterization under ECG guidance. One senior radiologist and two radiologists in training independently read the CXRs, and determined whether the CVC tip ended in the RA and measured the vertical distance from the CVC tip to the carina (TC-distance). RESULTS: Two hundred twelve CVC tips could be identified by TEE. Only left-sided CVCs (n = 5) ended in the upper RA (2.4%). Three of those patients were shorter than 160 cm. Specificity was 94% for senior radiologist, 44% for the first radiologist in training, and 60% for the second radiologist in training. The TC-distance of intraatrial catheters was 39, 55, 59, 80, and 83 mm, respectively. Thus, a TC-distance < or = 55 mm ensured extraatrial tip position in four of five intraatrial CVCs (80%, p = 0.002). The TC-distance of extraatrial catheters ranged from - 26 to 102 mm. CONCLUSIONS: Reading of a bedside CXR alone is not very accurate to identify intraatrial CVC tip position. TC-distance is a helpful marker, and its specificity is as good as that of an experienced radiologist if a cutoff value of 55 mm is chosen.

The pivotal role of vasopressin in refractory anaphylactic shock.

BACKGROUND: Severe anaphylaxis can be associated with cardiovascular collapse that is difficult to manage and does not respond to treatment with epinephrine. Because anaphylaxis is uncommon, unpredictable and may be fatal, a prospective, randomized, controlled trial in humans on the best management is difficult and guidelines are based on theory and anecdotes only. METHODS AND RESULTS: We report six cases in which the use of vasopressin was successful in the treatment of anaphylactic shock. CONCLUSIONS: Standard treatment of anaphylactic shock, including discontinuation of the causative agent, administration of epinephrine, and infusion of IV fluids, did not stabilize cardiocirculatory function, and adding arginine vasopressors resulted in prompt hemodynamic stabilization.