Factors that influence flow through intravascular catheters: the clinical relevance of Poiseuille's law

Incidence and risk factors for central venous access device failure in hospitalized adults: A multivariable analysis of 1892 catheters

BACKGROUND

Central venous access devices (CVADs) allow intravenous therapy, haemodynamic monitoring and blood sampling but many fail before therapy completion.

OBJECTIVE

To quantify CVAD failure and complications; and identify risk factors.

DESIGNS, SETTINGS, AND PARTICIPANTS

Secondary analysis of multicentre randomised controlled trial including patients aged ≥16 years with a non-tunnelled CVAD (NTCVAD), peripherally-inserted central catheter (PICC) or tunnelled CVAD (TCVAD). Primary outcome was incidence of all-cause CVAD failure (central line-associated bloodstream infection [CLABSI], occlusion, accidental dislodgement, catheter fracture, thrombosis, pain). Secondary outcomes were CLABSI, occlusion and dislodgement. Cox regression was used to report time-to-event associations.

RESULTS

In 1892 CVADs, all-cause failure occurred in 10.2% of devices: 49 NTCVADs (6.1%); 100 PICCs (13.2%); 44 TCVADs (13.4%). Failure rates for CLABSI, occlusion and dislodgement were 5.3%, 1.8%, and 1.7%, respectively. Independent CLABSI predictors were blood product administration through PICCs (hazard ratio (HR) 2.62, 95% confidence interval (CI) 1.24-5.55); and in TCVADs, one or two lumens, compared with three to four (HR 3.36, 95%CI 1.68-6.71), intravenous chemotherapy (HR 2.96, 95%CI 1.31-6.68), and diabetes (HR 3.25, 95%CI 1.40-7.57). Independent factors protective for CLABSI include antimicrobial NTCVADs (HR 0.23, 95%CI 0.08-0.63) and lipids in TCVADs (HR 0.32, 95%CI 0.14-0.72). NTCVADs inserted at another hospital (HR 7.06, 95%CI 1.48-33.7) and baseline infection in patients with PICCs (HR 2.72, 95%CI 1.08-6.83) were predictors for dislodgement. No independent occlusion predictors were found. Modifiable risk factors were identified for CVAD failure, which occurred for 1-in-10 catheters. Strict infection prevention measures and improved CVAD securement could reduce CLABSI and dislodgement risk.

The Efficacy of Intraosseous Access for Initial Resuscitation in Patients with Severe Trauma: A Retrospective Multicenter Study in South Korea

Background/Objective: In patients with severe trauma, intraosseous (IO) access is an alternative when intravenous (IV) access proves challenging. However, detailed insights into its utilization patterns and effectiveness are lacking. This study aims to evaluate the use and efficacy of IO access in hemodynamically unstable patients with trauma at level-1 trauma centers in South Korea. Methods: Data from six centers over 12 months were analyzed, focusing on patients with traumatic cardiac arrest or shock. Overall, 206 patients were included in the study: 94 in the IO group and 112 in the IV group. Results: The first-attempt success rate was higher in the IO group than in the IV group (90.4% vs. 75.5%). The procedure time in the IO group was also shorter than that in the IV group. The fluid infusion rate was lower in the IO group than in the IV group; however, the use of a pressure bag with IO access significantly increased the rate, making it comparable to the IV infusion rate. Further, regarding IO access, a humeral site provided a higher infusion rate than a tibial site. Conclusions: IO access offers a viable alternative to IV access for the initial resuscitation in patients with trauma, providing advantages in terms of procedure time and first-attempt success rate. The use of a pressure bag and a humeral site for IO access afforded infusion rates comparable to those associated with IV access.

The influence of needleless connectors and inserted catheters on flow rates through vascular introducer sheaths

SummaryA vascular introducer sheath is often used for rapid volume replacement. However, common manipulations such as the addition of needleless connectors to infusion ports and the insertion of catheters or other devices through the introducer sheath may impede flow. In this study we utilised a rapid infuser to deliver room-temperature normal saline through two introducer sheath configurations with and without the addition of needleless connectors and the placement of catheters through the introducer sheaths. The maximal flow rate delivered by the rapid infuser was 1000 mL/min, which was observed with both introducer sheath sizes tested without additional resistive elements. However, with the addition of a needleless connector, flow rates through the introducer sheaths were substantially lower (64 (standard deviation (SD) 6) mL/min and 61 (SD 7) mL/min for the 8.5 Fr and 9 Fr introducers, respectively). Flow rates were also reduced when catheters were placed within the sheaths (298 (SD 9) mL/min with the 7 Fr catheter and 74 (SD 9) mL/min with the 8 Fr catheter placed in an 8.5 Fr sheath; 649 (SD 6) mL/min with the 7 Fr catheter and 356 (SD 14) mL/min with the 8 Fr catheter placed in the 9 Fr sheath). These findings indicated that both needleless connectors and the placement of catheters through vascular introducer sheaths substantially reduced potential flow rates. Even 'large' vascular introducer sheaths capable of delivering high flow rates could be rendered minimally effective for rapid fluid administration when used in this way. Clinicians should consider these impediments to flow when rapid fluid administration is required, and obtain alternative vascular access if necessary.

Trauma Bay Evaluation and Resuscitative Decision-Making

The reader of this article will now have the ability to reflect on all aspects of high-quality trauma bay care, from resuscitation to diagnosis and leadership to debriefing. Although there is no replacement for experience, both clinically and in a simulation environment, trauma clinicians are encouraged to make use of this article both as a primer at the beginning of a trauma rotation and a reference text to revisit after difficult cases in the trauma bay. Also, periods of reflection seem appropriate in the busy but, of course, rewarding career in trauma care.

Evaluation of the Catheter Clamp over Hydrophilic Guide Wire Central Venous Catheter Exchange Technique for Air Embolism Prophylaxis in an In Vitro Model

PURPOSE

To develop a reproducible in vitro model simulating central venous catheter (CVC) exchange with high potential for air embolization and test the hypothesis that a closed catheter clamp over hydrophilic guide wire exchange technique will significantly reduce the volume of air introduced during CVC exchange.

MATERIALS AND METHODS

The model consisted of a 16-F valved sheath, 240-mL container, and pressure transducer submerged in water in a 1,200-mL suction canister system. Continuous wall suction was applied to the canister to maintain negative pressure at -7 mm Hg or -11 mm Hg. Each trial consisted of 0.035-inch hydrophilic guide wire introduction, over-the-wire catheter exchange, and wire removal following clinical protocol. A total of 256 trials were performed, 128 trials at each pressure with the catheter clamp open (n = 64) or closed (n = 64) around the hydrophilic guide wire.

RESULTS

There was a statistically significant lower volume of air introduced with closed clamp over-the-wire exchanges than with open clamp exchanges at both pressures (2-tailed t-test, P < .001). At -7 mm Hg, a mean of 48.0 mL (SD ± 9.3) of air was introduced with open clamp and 20.6 mL (SD ± 4.7) of air was introduced with closed clamp. At -11 mm Hg, 97.8 mL (SD ± 11.9) of air was introduced with open clamp and 37.8 mL (SD ± 6.3) of air was introduced with closed clamp.

CONCLUSIONS

This study demonstrated the use of a reproducible in vitro model mimicking conditions causing air embolism during CVC exchange. Results showed that CVC exchange using closed catheter clamp over hydrophilic guide wire exchange technique significantly reduced the volume of air introduced per exchange.

Transfusion Practice: Hemolysis Markers After In Vitro Infusion of Packed Red Blood Cells by the Gravitational Method in Peripheral Catheter

The objective of this study was to compare hemolysis marker levels after in vitro infusion of red blood cells (RBCs) according to storage time, infusion rate, and peripheral intravenous catheter size. This is an experimental study with randomly administered RBCs in quintuplicate, according to storage time shorter than and longer than 14 days, as well as infusion rate (50 mL/h and 100 mL/h) using catheters with calibers of 14-, 18-, and 20-gauge. Aliquots were collected from RBCs (V1), after equipment and catheter (V2) free-flow filling and after controlled infusion through the catheter (V3). The hemolytic markers analyzed were degree of hemolysis (%), hematocrit (Ht) (%), total hemoglobin (THb) (g/dL), free hemoglobin (FHb) (g/dL), potassium (K) (mmol/L), and lactate dehydrogenase (LDH) (U/L), considering a probability of error ≤5%. Sixty experiments were performed with the analysis of 180 aliquots. When RBCs aged <14 days were used, all catheters tended to increase THb, FHb, and K; while >14 days, RBCs presented increased FHb and degree of hemolysis with catheters of 18-gauge and THb levels at 14-gauge. Among the conditions analyzed, only 20-gauge catheters (the smallest) did not influence changes in hemolysis markers, regardless of RBC storage time.

Controlling peripheral intravenous catheter failure by needleless connector design: A pilot randomised controlled trial

AIM

To test the feasibility of a study protocol that compared the efficacy of neutral- and negative-pressure needleless connectors (NCs).

DESIGN

A single-centre, parallel-group, pilot randomised control trial.

METHODS

Our study compared neutral-(intervention) and negative-pressure (control) NCs among adult patients in an Australian hospital. The primary feasibility outcome was measured against predetermined criteria (e.g. eligibility, attrition). The primary efficacy outcome was all-cause peripheral intravenous catheter failure, analysed as time-to-event data.

RESULTS

In total, 201 (100 control; 101 intervention) participants were enrolled between March 2020 and September 2020. All feasibility criteria were met except eligibility, which was lower (78%) than the 90% criterion. All-cause peripheral intravenous catheter failure was significantly higher in the intervention group (39%) compared to control (19%).

CONCLUSION

With minor modifications to participant screening for eligibility, this randomised control trial is feasible for a large multicentre randomised control trial. The neutral NC was associated with an increased risk of peripheral intravenous catheter failure.

IMPLICATIONS FOR THE PROFESSION AND/OR PATIENT CARE

There are several NC designs available, often identified by their mechanism of pressure (positive, negative and neutral). However, NCs can contribute to peripheral intravenous catheter failure. This is the first randomised controlled trial to compare neutral and negative NC designs. Negative pressure NCs had lower PIVC failure compared to neutral NCs, however the results might not be generalisable to other brands or treatment settings. Further high-quality research is needed to explore NC design.

REPORTING METHOD

Study methods and results reported in adherence to the CONSORT Statement.

PATIENT OR PUBLIC CONTRIBUTION

No patient or public contribution.

The Effects of Intravenous Fluid Viscosity on the Accuracy of Intravenous Infusion Flow Regulators

Intravenous infusion flow regulators (IIFRs) are widely used devices but it is unknown how much the difference between the IIFR scale and the actual flow rate depends on the viscosity of the intravenous (IV) fluid. This study evaluated the effects of viscosity on the flow rate of five IV fluids (0.9% normal saline, Hartmann's solution, plasma solution-A, 6% hetastarch, and 5% albumin) when using IIFRs. The viscosity of crystalloids was 1.07-1.12 mPa·s, and the viscosities of 6% hetastarch and 5% albumin were 2.59 times and 1.74 times that of normal saline, respectively. When the IIFR scales were preset to 20, 100, and 250 mL/hr, crystalloids were delivered at the preset flow rate within a difference of less than 10%, while 6% hetastarch was delivered at approximately 40% of the preset flow rates and 5% albumin was approximately 80% transmitted. When delivering colloids, IIFRs should be used with caution.

Optimal Design and Biomechanical Analysis of a Biomimetic Lightweight Design Plate for Distal Tibial Fractures: A Finite Element Analysis

The treatment of fractures of the distal tibia can be problematic due to the insubstantial soft-tissue covering this part of the anatomy. This study investigates a novel strategy for minimally invasive plate osteosynthesis of distal tibia fractures called bionic lightweight design plating. Following the structure of the animal trabecular bone, we utilized topological mathematical methods to redesign the material layout of the internal fixation device to fulfill the desired lightweight design within given boundary conditions. The results showed that this method can maintain the same stability of the construct as the original plate after a reduction in the original volume by 30%, and the differences in strain energy of plates and maximum node displacement of constructs between the constructs [RP construct vs. LP construct] were not statistically significant (p > 0.05). In the safety assessment of the constructs, the peak stress of plates between constructs was found to not be statistically significantly different under a doubled physiological load (p > 0.05). The average stress of the plates’ elements exceeding the allowable stress was analyzed, and no statistically significant differences were found between the two constructs under axial compression stress conditions (p > 0.05). The average stress of the plates’ elements in the redesigned plating construct under torsional stress conditions was 3.08% less than that of the locked plating construct (p < 0.05). Under the double physiological load condition, 89% of the elements of the plate in the redesigned plating construct and 85% of the elements of the plate in the locked plating construct were lower than the maximum safe stress of the plate, which was 410 MPa (secondary allowable stresses). That reminds us the topology optimization offer a possible way to improve the capacity of soft tissue protection while ensuring the safety of the RP construct by reducing the volume of the implants.

An early analysis of Codman® CerebroFlo® Endexo coated ventricular catheters in the setting of intraventricular hemorrhage

BACKGROUND

Intraventricular hemorrhages (IVH) are a potentially fatal diagnosis that must be managed properly to avoid devastating complications. While existing catheters have offered relative success, their reactive composition makes them prone to eventual obstruction and thrombotic activation. This problematic outcome has led to emergence of the Codman® CerebroFlo® EVD Catheter. This catheter is the first of its kind to incorporate the Endexo additive, a slightly reactive, surface modifying molecule that prevents protein adhesion and biomatter accumulation.

METHODS

Despite the promising early outcomes, there are no PubMed articles characterizing this device, with minimal literature highlighting its clinical value. Through a contemporary literature review, the authors will characterize the technological principles, indications, and advantages of this novel device.

RESULTS

The authors report the early findings of this catheter, with studies showing 99% reduction in thrombotic activity with an additional 89% reduction in catheter obstruction compared to its competitors. Areas of uncertainty regarding this device are discussed, with its lack of antibiotic coating being a possible area for clinical concern.

CONCLUSIONS

the CerebroFlo® catheter is a novel and effective tool in the management of IVH that should be widely considered for the management of IVH.

PICC entrapment and air embolism on veno-venous extracorporeal membrane oxygenation: A case report

Extracorporeal membrane oxygenation (ECMO) is an incredible, life-sustaining intervention for patients suffering from a variety of cardiopulmonary insults. However, its use comes with a unique set of risks and potentially devastating complications, including air entrainment and embolism. We present a case of recurrent air entrainment in a patient on veno-venous ECMO after her peripherally inserted central catheter became entrapped within the lumen of her bi-caval, dual lumen ECMO cannula. We briefly discuss considerations for air embolism on ECMO and recommend general strategies to avoid this potentially catastrophic complication.

Performance assessment of intravenous catheters for massive transfusion: A pragmatic in vitro study

BACKGROUND

Rapid infusion of warmed blood products is the cornerstone of trauma resuscitation and treatment of surgical and obstetric massive hemorrhage. Integral to optimizing this delivery is selection of an intravenous (IV) catheter and use of a rapid infusion device (RID). We investigated which IV catheter and RID system enabled the greatest infusion rate of blood products and the governing catheter characteristics.

STUDY DESIGN AND METHODS

The maximum flow rates of nine IV catheters were measured while infusing a mixture of packed red blood cells and fresh frozen plasma at a 1:1 ratio using a RID with and without a patient line extension. To account for IV catheters that achieved the RID's maximum 1000 ml/min, the conductance of each infusion circuit configuration was calculated.

RESULTS

IV catheters of 7-Fr caliber or higher reached the maximum pressurized flow rate. The 9-Fr multi-lumen access catheter (MAC) achieved the greatest conductance, over sevenfold greater than the 18 g peripheral catheter (4.6 vs. 0.6 ml/min/mmHg, p < .001). Conductance was positively correlated with internal radius (β = 1.098, 95% CI 4.286-5.025, p < .001) and negatively correlated with length (β= - 0.495, 95% CI -0.007 to 0.005, p < .001). Use of an extension line (β= - 0.094, 95% CI -0.505 to -0.095, p = .005) was independently associated with reduced conductance in large caliber catheters.

CONCLUSION

Short, large-diameter catheters provided the greatest infusion rates of massive transfusion blood products for the least pressure. For patients requiring the highest transfusion flow rates, extension tubing should be avoided when possible.

Rapid Blood Transfusion: The Importance of Hemodilution and Needleless Connectors

Introduction: Large-bore cannulas are critical to administering IV fluids and blood products during resuscitation and treatment of hemorrhage. Although catheter flow rates for crystalloid solutions are well defined, rapid administration of blood products is poorly characterized. In this in vitro study, we examined the effects of hemodilution and needleless connectors on red blood cell (RBC) flow rates.

Methods: To determine RBC flow rates through large-bore cannulae, a crystalloid solution (Normosol®, Hospira, Lake Forest, IL) or RBC units were warmed and delivered under pressure (360 mmHg) using a Level 1 H-1200 Fast Flow Fluid Warmer (Smiths Medical, St. Paul, MN). Flow rates for crystalloid, packed RBCs and diluted RBCs were determined using a stopwatch. Additionally, the effect of the MaxPlus® clear needleless connector (CareFusion, San Diego, CA) was measured in all three infusion groups.

Results: Flow rates for undiluted RBC units were 53% slower than crystalloid solution (220 mL/min vs. 463 mL/min; p=0.0003), however, when RBC units were diluted to a hematocrit of ~30% flow rate improved to 369 mL/min (p=0.005). The addition of the MaxPlus® needleless connector reduced flow of crystalloid solution by 47% (245 mL/min; p=0.0001), undiluted RBCs by 64% (78 mL/min; p=0.01), and diluted RBCs by 51% (180 mL/min; p=0.00003). Compared to undiluted RBC units, hemodilution increased RBC delivery rate through a MaxPlus® connector by 130% (p=0.004) and by 68% (p=0.02) when the catheter was directly connected to the Level 1 tubing (MaxPlus® excluded).

Conclusion: In settings requiring rapid transfusion of RBC units, needleless connectors should not be used and hemodilution should be considered in order to decrease the time required to deliver an equivalent red cell mass.