Thinking about physics…. and IV therapy: The pressure’s on! Melissa M. Otoya RNC University of Virginia Children’s Hospital: Neonatal ICU Introduction As care and technology for our most vulnerable neonatal population improves, so does our dependence upon centrally placed vascular access devices. The use of these devices, along with the multiple options and variables associated with tubing adjuncts and infusion pumps, has potential to create practice variation, knowledge gaps, and confusion for caregivers in the NICU. Just how much does the typical NICU nurse know about catheters, tubing adjuncts, infusate solutions, infusion pump devices, and the potential relationships to complications of intravenous therapies? Do our educational efforts, either associated with product training, new hire orientation, or staff development provide for a clear understanding? With recent emphasis on reduction of morbidities associated with infusion therapy, the tools and framework of knowledge that the nurse has is imperative to the ability to minimize risks associated with long term IV therapy. Beyond the emphasis on reduction of catheter associated blood stream infection, this focus on product selection, nursing knowledge, and practice patterns will hopefully engage further thought into the associated physics, pathophysiology of thrombus/ thromboembolism formation and relationship to patient outcomes such as interrupted fluid/medication delivery, catheter occlusion, bio-film development, and catheter related blood stream infection. Ah-ha! The clot thickens!!!!!! Neonatal Thrombosis / Thromboembolism v “Relative” prothrombotic state of newborn is balanced by other factors that prevent a term or relatively well premature infant from experiencing spontaneous thromboses. v When this “balance” is disrupted, the neonate is at high risk for thromboses development. v Specifically, infection promotes clotting activation and catheters provide a center for thrombus formation. v Alternatively, the plastic CVC surface promotes platelet activation and thrombus formation. The thrombus and its ligands promote adherence of local bacteria. v Clinical significance of neonatal thrombosis varies from asymptomatic incidents to life or limb-threatening events. The Problem Infusion device characteristics and differences Prescription for the problem Over a six month period in the NICU at the University of Virginia Children’s Hospital, the incidence and prevalence of line occlusion, as well as thromboembolism (TE) requiring long term anticoagulant therapy had increased. Large volume pump – peristaltic flow device Staff Education: Mandatory annual skills fair venue In addition to application of IHI - Central Line Care bundle, practice changes in the months preceding these outcomes included: • Abandonment of the practice of locking central vascular catheters (CVC, PICC, UVC). • Use of KVO rate to maintain patency if maintenance of catheter is deemed necessary, thereby reducing number of entries into IV system. • Reduction of standard KVO rate from 2 ml/hr to 1 ml/hr. • Standardization of tubing configuration inclusive of closed medication delivery system. • Sterile procedure for tubing assembly and change procedures. • Placement of needleless injection cap on any point in tubing configuration likely to be entered and specific injection cap antiseptic prep procedures. v Data from three international registries demonstrated that approximately 90% of venous thromboses in neonates were associated with CVC’s. v Overall size of catheter in relation to small vessel lumen creates risk for obstruction of blood flow and can be mechanical source of endothelial damage to vessel wall. v. Whereas daily re-evaluation of need for CVC or umbilical catheter as well as use of heparinized solutions have been recommended in the medical literature as preventative strategies, our findings suggest that infusion therapy devices, product characteristics, and user interface may well have a significant relationship to outcomes. Syringe infusion pump • Typically offer +/- 2% delivery accuracy. • Positive linear displacement device that utilizes a gear reduction mechanism and a lead screw. • Computer controlled motor turns the screw that ultimately provides positive force to the plunger on a syringe. • Specifically designed to deliver small volumes and low flow rates. • Mechanism allows for enhanced continuity of flow with shorter frequency intervals and minimal relaxed time. • “Mechanical gap” or “slack” can have a significant impact on start up time, resulting in delay of infusion unless specific priming procedures are consistently understood and employed. Additional relevant practices / observations include: • Standard needleless injection cap is a split-septum, low prime volume product that exerts a negative pressure upon de-access. • Large-volume, peristaltic flow infusion pumps are used primarily for infusion of maintenance IV fluids, and TPN, and frequently at KVO rate. • Syringe infusion pumps are used for continuous drip medication delivery, intermittent medication, and intralipid infusions. • Routine practice of addition of heparin to IV solution for all central venous lines and arterial lines. (0. 5 – 1 unit/ml) • Syringe pump event logs indicated non-compliance with priming procedures as well as presence of alarms indicating increasing pressure in system preceding occlusion outcomes. (early occlusion detection system) • Routine prophylactic flushing of CVC, PICC devices is not a standard practice for NICU patient population. • Moderate nursing turnover with continuous new hire orientation and preceptor variability. • Some use of agency (travel) nursing staff with abbreviated orientation provided. Analysis of problem and contributing factors v With acute rise in catheter occlusion rates as well as incidence of thromboembolism, practice patterns and knowledge gaps are suspect as contributory. v Investigation of specifications and operational details of infusion devices provided insight to understanding variability in flow continuity of these devices, especially at low rate infusions. v Survey of staff revealed that pump selection was inconsistent and did not convey operational understanding of differences between the devices and safety features. v Survey also provided concerning insight regarding staff knowledge gaps and practice relevant to needleless injection cap. (Increased incidence of catheter occlusion, particularly in smaller lumen catheters where longer length of catheter is filled by reflux displacement of blood upon disconnection, has been previously reported. ) v Event log reports from infusion devices demonstrated non-compliance with pump priming procedures as well as lack of understanding and significance of “early” occlusion alarms. v To proceed with staff education and changes in practice, the project would require budgetary allocation for nursing education, system changes in computerized order entry, medical staff engagement and pharmacy leadership involvement. Given anecdotal observations, detail gleaned from infusion device event logs, and a couple of well thought out assumptions, we developed a survey of “suspect” infusion practices and product choices that validated some of our concerns regarding practice inconsistencies and well as knowledge gaps. (68% response rate) The following selected questions and responses provided us with some direction. • Explained differences in pump features, specifications, and recommendations to improve flow continuity for low flow rates as well as high risk medication delivery. • Specific attention given to procedure for “pump priming” to overcome mechanical slack and improve start-up time and avoid stasis in catheter as well as delayed delivery of fluid/medications. Lots of visuals are helpful to create understanding of this concept. • Infusion pump manufacturer recommendations for improving flow accuracy; choice of syringe size and use of low volume tubing sets. • Discussion of negative pressure feature of the needleless injection port with “live” demonstration of “reflux” that occurs upon disconnect. This was very effective! • Tubing change procedures and steps involving disconnect from injection cap, with specific emphasis on clamping prior to disconnect to prevent reflux into catheter. System and practice changes • Standardized steps in initiation of infusion or tubing change to always include pump priming procedure prior to connect to patient. • Computerized physician order system changed to include specification of KVO fluid orders to be dispensed in a syringe. (Syringe size chosen based upon flow rate) • Extension sets, CVL, or tubing always clamped upon de-access from needleless injection ports. Outcomes • Although methods of catheter complication data collection (at the time of problem identification and 1 year following) are not conducive to scientific analysis, anecdotal and reported catheter occlusion rates declined. • There has been significant reduction of CVC related thromboembolism outcome. (almost eliminated) • Staff orientation and training relevant to infusion therapy has consistent elements. • Identification for need to implement systematic central line outcome data collection for quality and performance improvement purposes. To be developed within EMR. (process currently underway) Conclusions and implications for nursing v Upon de-access or disconnect from the needless injection cap, v Neonatal population has unique IV therapy needs and potential for morbidities. _____? ______ pressure is created. Negative pressure Positive pressure Neutral pressure • Discussion of survey findings and conclusions regarding product, practice, and knowledge gaps as potential contributing factors in development of occlusion, thrombus / thromboembolism outcomes. • Syringe infusion pumps to be used for KVO rates. When in doubt………. . SURVEY! v Incidence has been reported between 2. 4 – 5. 1 per 1000 newborns admitted to NICUs. (1995, 1997) v. Incidence statistics are expected to have increased since these earlier reports as a result of ever increasing use of central venous catheters (CVC, PICC), as well as umbilical catheters (UVC, UAC). • Typically offer +/- 5% delivery accuracy. • Most common mechanism is a linear peristaltic device which uses fingerlike projections to occlude tubing successively in a rippling wave–like motion. • Tubing is held against a stationary plate and is alternately compressed and released by moving fingers, forcing fluid flow. • At low infusion rates this may result in longer frequency intervals with significant “relax” time. • Fluid flow is “cyclic” and may cause significant fluctuations in flow rate and continuity. 77. 5% 16. 9% 5. 6% v Nursing staff education needs to address these unique differences in both practical and didactic components of orientation and in-service training. v When I de-access – disconnect tubing or syringe during routine tubing or syringe changes, I will _______. Clamp the catheter or extension set 91. 5% Not clamp the CVC or extension set if it has an injection cap 4. 2% Sometimes clamp, depends upon what medication is infusing 4. 2% v Products used with infusion therapy need to be implemented with thorough staff education, including skill and knowledge competency validation. v When I am running fluids through a central line or PICC at KVO rate, the infusion pump I typically use is……. Large volume (peristaltic flow) pump 45. 1% Syringe pump 32. 4% Choice depends on total fluid volume and MD orders 23. 9% Whatever pump available 2. 8% v. Further studies of the pathophysiology of thrombosis and infection are warranted with emphasis on preventative interventions inclusive of variables associated with infusion devices, and infusion system tubing adjuncts, especially needleless injection caps. Acknowledgements I would like to specifically acknowledge Danielle Ottinger MSN, NNP for her assistance with creation and conduction of the staff survey. Additionally, it is the honor of working with such a dedicated medical and nursing staff in the NICU at the University of Virginia’s Children’s Hospital that supports and celebrates continuous inquiry of practice to improve care to our most vulnerable patients and their families. v Infusion product selection and implementation processes must have representation by end users. Failure Mode and Effects Analysis Model (ISMP) provides a good framework for product and practice analyses. References: 1. 2. ECRI Institute. Needleless Connectors. Health Devices. Sept 2008: 262 – 318 ECRI Institute. Health. Care Product Comparison System: Infusion Pumps, general purpose. 2007. Accessed 8/11/2010. http: //www. ecri. org/Documents/HPCS_Infusion_Pumps. pdf 3. Neff SB, Neff TA, Gerber S, Weiss MM. Flow rate, syringe size, and architecture are critical to start up performance of syringe pumps. European J Anaesthesiology. 2007; 24(7): 602 -608 4. Ryder M. Evidence-based practice in the management of vascular access devices for home parenteral nutrition therapy. JPEN. 2006; 30(1): S 82 -S 93. 5. Saxonhouse MA, Burchfield DJ. The evaluation and management of postnatal thromboses. J Perinatology. 2009; 29: 467 -478. 6. Thornburg CD, Smith PB, Smithwick ML, Cotton CM, Benjamin DK, Jr. Association between thrombosis and bloodstream infection in neonates with peripherally inserted catheters. Thrombosis Research. 2008; 122: 782 -785. 7. Veldman A, Nold, MF, Michel-Behnke I. Thrombosis in the critically ill neonate: incidence, diagnosis, and management. Vascular Health and Risk Management. 2008; 4(6): 1337 -1348. For further information: Contact: Melissa Otoya RNC mo 9 w@hscmail. mcc. virginia. edu
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