Dosing errors in preterm neonates due to flow rate variability in multi-infusion syringe pump setups: An in vitro spectrophotometry study

Effect of vertical stopcock position on start-up fluid delivery in syringe pumps used for microinfusions

The purpose of this in vitro study was to evaluate the impact of the vertical level of the stopcock connecting the infusion line to the central venous catheter on start-up fluid delivery in microinfusions. Start-up fluid delivery was measured under standardized conditions with the syringe outlet and liquid flow sensors positioned at heart level (0 cm) and exposed to a simulated CVP of 10 mmHg at a set flow rate of 1 ml/h. Flow and intraluminal pressures were measured with the infusion line connected to the stopcock primarily placed at vertical levels of 0 cm, + 30 cm and - 30 cm or primarily placed at 0 cm and secondarily, after connecting the infusion line, displaced to + 30 cm and - 30 cm. Start-up fluid delivery 10 s after opening the stopcock placed at zero level and after opening the stopcock primarily connected at zero level and secondary displaced to vertical levels of + 30 cm and - 30 cm were similar (- 10.52 [- 13.85 to - 7.19] µL; - 8.84 [- 12.34 to - 5.33] µL and - 11.19 [- 13.71 to - 8.67] µL (p = 0.469)). Fluid delivered at 360 s related to 65% (zero level), 71% (+ 30 cm) and 67% (- 30 cm) of calculated infusion volume (p = 0.395). Start-up fluid delivery with the stopcock primarily placed at + 30 cm and - 30 cm resulted in large anterograde and retrograde fluid volumes of 34.39 [33.43 to 35.34] µL and - 24.90 [- 27.79 to - 22.01] µL at 10 s, respectively (p < 0.0001). Fluid delivered with the stopcock primarily placed at + 30 cm and - 30 cm resulted in 140% and 35% of calculated volume at 360 s, respectively (p < 0.0001). Syringe infusion pumps should ideally be connected to the stopcock positioned at heart level in order to minimize the amounts of anterograde and retrograde fluid volumes after opening of the stopcock.

Effect of central venous pressure on fluid delivery during start-up of syringe infusion pumps for microinfusion

BACKGROUND

Intravenous administration of highly concentrated and potent drugs at low flow rates is common practice, particularly in critically ill children. Drug delivery during infusion start-up can be considerably delayed by intrinsic factors of syringe infusion pump assemblies. The impact of central venous pressures on the course of start-up fluid delivery of such microinfusions remains unknown.

METHODS

Infusion volumes delivered after activation of the start button in a conventional 50 mL syringe infusion pump assembly equilibrated (representing classical in vitro testing) and not equilibrated (representing real clinical conditions) to central venous pressure levels of 0, 10 and 20 mmHg at a set infusion flow rate of 1 mL/h were measured using a fluidic flow sensor.

RESULTS

The experimental setup mimicking real life conditions demonstrated considerable differences in fluid delivery during pump start-up depending on central venous pressure. A central venous pressure of 0 mmHg resulted in massive fluid delivery at infusion start-up, while central venous pressure levels of 10 and 20 mmHg resulted in retrograde flows with related mean (95% CI) zero-drug delivery times of 3.22 (2.98-3.46) min and 4.51 (4.33-4.69) min, respectively (p < .0001).

CONCLUSION

Depending on central venous pressure level, connection and starting a new syringe pump can result in significant antegrade or retrograde fluid volumes. In clinical practice, this can lead to hemodynamic instability and hence requires clinical alertness. Further research and methods to improve start-up performance in syringe infusion pump systems are desirable.

Good handling practice of parenterally administered medicines in neonatal intensive care units - position paper of an interdisciplinary working group

This position paper, developed by an interdisciplinary expert group of neonatologists, paediatric infectious disease physicians, clinical pharmacists and specialists for the prevention and control of nosocomial infections, describes the "Good handling practice of medicines parenterally administered to patients on NICUs". It takes equal account of patient safety and the specialties of neonatal intensive care regarding feasibility and proportionality. The overall concept is perceived as a "learning system", in which open communication within the health-care team relating to medication errors and critical incidents enables continuous development and improvement to ensure patient safety. In our opinion, pharmacists, who are responsible for the supply of ready-to-administer parenteral medicinal products for neonatal intensive care patients, as well as the hygiene staff responsible on site are integral parts of the interdisciplinary treatment team. Risks of the current clinical practice of parenteral treatment of NICU patients are discussed in detail and recommendations for safety-relevant procedures are given.

Metrology in health: challenges and solutions in infusion therapy and diagnostics

The significance of Metrology in infusion therapy and diagnostics, both critical in health care safety and quality, is discussed in this article. Although infusion therapy is the most used form of drug administration, infusion errors are often made with reported dramatic effects in different applications, especially in neonatology. Adverse incidents, morbidity, and mortality have often been traced back to poor or inaccurate dosing. For critical infusion applications to vulnerable patients, well-controlled medication administration might be accomplished by improved dosing accuracy, traceable measurement of volume, flow, and pressure in existing drug delivery devices and in-line sensors operating at very low flow rates. To this end, the contribution of recently upgraded metrological infrastructures in European Metrology Institutes to a safer infusion therapy in health care is described in detail. Diagnostics, on the other hand is a sector characterized by rapid developments further triggered recently by the necessity for the management and prevention of infectious diseases like COVID-19. In this context, the impact of metrology in future large-scale commercialization of next generation diagnostics (e.g., point-of-care) is highlighted. Moreover, the latest contributions of Metrology in the development of traceable testing methods and protocols to ensure the sensitivity and accuracy of these devices are described.

Clinical Effects of Inadvertent Increased Lipid Infusion in Neonates: Two Case Reports

BACKGROUND

Utility of total parenteral nutrition (TPN) with an intravenous lipid emulsion (IVLE) component is common in the neonatal intensive care unit; however, there are inherent risks to TPN use. With IVLE administered separate from other TPN components, opportunities exist for additional error and subsequent potential harm.

CLINICAL FINDINGS

We present 2 cases in term infants where IVLE infusions were noted to be inadvertently administered at higher than prescribed rates, prompting concern for lipemia and end-organ damage due to hyperviscosity.

PRIMARY DIAGNOSIS

Both infants developed iatrogenic hypertriglyceridemia and hyponatremia.

INTERVENTION

Upon recognition of the error, IVLE was immediately discontinued in each case. Triglyceride levels were serially monitored until they reached a normal level. Electrolyte panels and hepatic function panels were also drawn to assess for electrolyte derangements and function. Radiologic studies were performed for evaluation of end-organ effects of hyperviscosity.

OUTCOMES

Triglyceride levels for both infants normalized within 7 hours. Both infants survived to discharge without any known effects related to the inadvertent excessive lipid infusion.

CONCLUSION

It is helpful to perform a root-cause analysis for these types of events; have the exact amount of lipids in the bag needed and no overfill; consider having lipids in 4-hour dosage aliquots; require 2 nurses to verify infusion rates hourly; and educational sessions and unit protocols for any infusion may reduce the risk of administration error.

Start-up delay in syringe infusion pumps with different rates and priming techniques of intravenoust sets

OBJECTIVE

To investigate infusion pumps start-up delay according to different brands of infusion pumps, flow rates and intravenous sets priming techniques.

METHOD

The experimental study simulated clinical practice under controlled conditions, using a 50 mL syringe with NaCl 0.9% solution, two syringe infusion pumps (A and B), six rates (0.3, 0.5, 1.0, 5, 10 and 20 mL/h), two purging techniques (manually or infusion pump's electronic bolus). Data were analyzed according to mean, standard deviation, Student's t and ANOVA tests (p<0.05).

RESULTS

The start-up delay was greater in low rates regardless the priming technique. The electronic bolus increased the infusion pump A accuracy at 0.3mL/h (p=0.010), 0.5 mL/h (p=0.002) and 1.0mL/h (p=0.004). Pump's accuracy in all studied rates and manual IV sets filling was similar.

CONCLUSION

In low infusion rates the start-up delay was greater despite the infusion pump brand and electronic bolus improved pumps accuracy.

Atraso na inicialização em bombas de infusão por seringa com diferentes velocidades de infusão e técnicas de preenchimento do sistema de infusão

RESUMO Objetivo: Verificar o atraso de inicialização de bomba de infusão, segundo diferentes marcas de bombas de infusão, velocidades e técnicas de preenchimento do sistema de infusão intravenosa. Método: Estudo experimental que simulou a prática clínica, utilizando seringas de 50 mL com solução de NaCl 0,9%, duas marcas de bombas de infusão por seringa (A e B), seis velocidades (0,3; 0,5; 1,0; 5; 10 e 20 mL/h), dois modos de preenchimento do sistema (manual ou eletrônico pelo modo bolus do equipamento). Os dados foram analisados segundo média, desvio padrão e testes t de Student e ANOVA (p<0,05). Resultados: O atraso na inicialização foi maior em velocidades baixas, independentemente da marca e modo de preenchimento. O preenchimento eletrônico aumentou a acurácia na bomba A em 0,3 mL/h (p=0,010), 0,5 mL/h (p=0,002) e 1,0 mL/h (p=0,004). A acurácia em preenchimento manual foi semelhante. Conclusão: Em baixas velocidades de infusão o atraso de inicialização foi maior e o preenchimento do sistema de infusão pelo modo eletrônico melhorou a acurácia dos equipamentos.

Simulation Analysis of Flow Rate Variability During Microinfusions: The Effect of Vertical Displacement and Multidrug Infusion in Conventional Infusion Pumps Versus New Cylinder-Type Infusion Pumps

BACKGROUND

Medication dosing errors can occur during microinfusions when there is vertical pump displacement or multidrug infusion through a single intravenous path. We compared flow rate variability between new-generation cylinder-type infusion pumps and conventional infusion pumps under simulated conditions.

METHODS

We evaluated the flow rates during microinfusions using different infusion pumps (syringe pump with 10/30/50-mL syringes, peristaltic pump, and cylinder pump). Two visible dyes were used as model drugs. The study samples were quantified using spectrophotometry. For vertical displacement, the infusion pumps were moved up and down by 60 cm during microinfusions at 0.5 mL·h-1 and 2 mL·h-1. In the multi-infusion study, the second drug flow was added through 4 linearly connected stopcocks either upstream or downstream of the first drug. We compared the total error dose between the cylinder pump and the syringe pump with a Mann-Whitney U test and additionally estimated the effects of the infusion pumps on total error doses by linear regression analysis.

RESULTS

There were repetitive patterns of temporary flow increases when the pump was displaced upward and flow decreases when the pump was displaced downward in all settings. However, the amount of flow irregularities was more pronounced at the lower infusion rate and in the syringe-type pump using larger volume syringes. The total error dose increased in the syringe pump loaded with a 50-mL syringe compared to that of the new cylinder pump (regression coefficient [β] = 4.66 [95% confidence interval {CI}, 1.60-7.72]; P = .008). The initiation and cessation of a new drug during multidrug microinfusion in the same intravenous path affected the lower rate first drug leading to a transient flow rate increase and decrease, respectively. The change in flow rate was observed regardless of the port selected for addition of the second drug, and the total error dose of the first drug did not significantly vary when an upstream or a downstream port was selected.

CONCLUSIONS

In the microinfusion settings, attention must be paid to the use of the syringe pump loaded with large-volume syringes. The novel cylinder pump could be considered as a practical alternative to syringe pumps with small syringes given its flow stability without the need for frequent drug replacement.

Performance of modern syringe infusion pump assemblies at low infusion rates in the perioperative setting

BACKGROUND

Syringe infusion pumps are used for the precise continuous administration of intravenous drugs. Their compliance and mechanical deficiencies have been found to cause considerable start-up delays, flow irregularities during vertical displacement, as well extensive delays of occlusion alarms at low infusion rates. The aim of this study was to evaluate the performance of several modern syringe infusion pumps at low infusion rates and the impact on drug concentration.

METHODS

Seven currently marketed syringe infusion pump assemblies were assessed in an in vitro study during start-up, vertical displacement manoeuvres, and infusion line occlusion at a set flow rate of 1 ml h^-1. The measured data were used as input for a pharmacokinetic simulation modelling plasma concentration during a standard neonatal continuous epinephrine infusion.

RESULTS

The mean time from starting the infusion pump to steady-state flow varied from 89 to 1622 s. The zero-drug delivery time after lowering the pump ranged from 145 to 335 s. In all assemblies tested, occlusion alarm delays and measured flow irregularities during vertical displacement manoeuvres resulted in relevant deviations in plasma epinephrine concentration (>25%) as calculated by the pharmacokinetic simulation model.

CONCLUSION

Problems with the performance of syringe infusion pump assemblies can have considerable impact on plasma drug concentration when highly concentrated short-acting cardiovascular drugs are administered at low flow rates. The problems, which affected all assemblies tested, are mainly related to the functional principle of syringe infusion pumps and will only partially be solved by incremental improvements of existing equipment.

Evaluation of a novel flow-controlled syringe infusion pump for precise and continuous drug delivery at low flow rates: a laboratory study

Syringe infusion pumps are used for the administration of short-acting drugs in anaesthesia and critical care medicine, but are prone to flow irregularities at low flow rates. A flow-controlled syringe infusion pump using an integrated flow sensor for feedback control represents a new approach to overcoming these limitations. This study compares the performance of a prototype flow-controlled syringe pump both at start-up, and during vertical displacement manoeuvres, with that of a standard infusion syringe pump. The novel pump almost completely eliminated delays at start-up and flow irregularities during hydrostatic pressure changes. Related fluctuations in plasma drug concentration were minimised and the known disadvantages of standard syringe infusion pumps currently used in clinical practice were reduced. Besides providing fast start-up to steady-state flow and precise continuous drug delivery at low flow rates during hydrostatic pressure changes, the new pump offers the potential for the development of target-controlled infusion algorithms for short-acting cardiovascular and other drugs.