Infusion System Architecture Impacts the Ability of Intensive Care Nurses to Maintain Hemodynamic Stability in a Living Swine Simulator

Cost-effectiveness of a new multi-lumen infusion device to reduce central-venous-line-associated bloodstream infections in neonates

BACKGROUND

A new medical device was developed for multi-infusion in neonatal intensive care units (NICUs) with the aim of addressing issues related to drug incompatibilities and central-line-associated bloodstream infections (CLABSIs).

AIM

To assess the cost-effectiveness of implementing this new perfusion system in an NICU setting.

METHODS

This single-centre, observational study was conducted in all infants admitted to the NICU within 3 days of birth, and who required a central venous line, to evaluate the cost and effectiveness before (2019) and after (2020) implementation of the new perfusion system. Costs were calculated from the hospital perspective, and the incidence of CLABSIs was examined over a time horizon from NICU admission to discharge. Resource utilization was measured (infusion device, infection-treating drugs and biological analyses), and corresponding costs were valued using tariffs for 2019. The incremental cost-effectiveness ratio (ICER) was calculated, expressed as Euros per CLABSI avoided, and one-way and multi-variate sensitivity analyses were conducted.

FINDINGS

Among 609 infants selected, clinical characteristics were similar across both periods. The CLABSI rate decreased significantly (rate ratio 0.22, 95% confidence interval 0.07-0.56), and total costs reduced from €65,666 to €63,932 per 1000 catheter-days (P<0.001) after implementation of the new perfusion system, giving an ICER of €251 saved per CLABSI avoided. The majority of sensitivity analyses showed that the new intervention remained economically dominant.

CONCLUSION

This single-centre study showed a significant decrease in the incidence of CLABSIs after implementation of the new perfusion system, without incurring additional costs. Further prospective multi-centre randomized studies are needed to confirm these results in other NICUs.

Drug Flow Through Clinical Infusion Systems: How Modeling of the Common-volume Helps Explain Clinical Events

This review aims to describe analytic models of drug infusion that demonstrate the impact of the infusion system common-volume on drug delivery. The common-volume of a drug infusion system is defined as the volume residing between the point where drug and inert carrier streams meet and the patient’s blood. We describe 3 sets of models. The first is quantitative modeling which includes algebraic mathematical constructs and forward-difference computational simulation. The second set of models is with in vitro benchtop simulation of clinical infusion system architecture. This modeling employs devices including pumps, manifolds, tubing and catheters used in patient care. The final set of models confirms in vitro findings with pharmacodynamic endpoints in living large mammals. Such modeling reveals subtle but important issues inherent in drug infusion therapy that can potentially lead to patient instability and morbidity. The common-volume is an often overlooked reservoir of drugs, especially when infusions flows are slowed or stopped. Even with medications and carriers flowing, some mass of drug always resides within this common-volume. This reservoir of drug can be inadvertently delivered into patients. When infusions are initiated, or when dose rate or carrier flow is altered, there can be a significant lag between intended and actual drug delivery. In the case of vasoactive and inotropic drug infusions, these unappreciated time delays between intended and actual drug delivery can lead to iatrogenic hemodynamic instability. When a drug infusion is discontinued, drug delivery continues until the common-volume is fully cleared of residual drug by the carrier. The findings from all 3 sets of models described in this review indicate that minimizing the common-volume of drug infusion systems may enhance patient safety. The presented models may also be configured into teaching tools and possibly point to technological solutions that might mitigate sources of iatrogenic patient lability.

Drug Infusion Systems: Technologies, Performance, and Pitfalls

This review aims to broadly describe drug infusion technologies and raise subtle but important issues arising from infusion therapy that can potentially lead to patient instability and morbidity. Advantages and disadvantages of gravity-dependent drug infusion are described and compared with electromechanical approaches for precise control of medication infusion, including large-volume peristaltic and syringe pumps. This review discusses how drugs and inert carriers interact within infusion systems and outlines several complexities and potential sources of drug error. Major topics are (1) the importance of the infusion system dead volume; (2) the quantities of coadministered fluid and the concept of microinfusion; and (3) future directions for drug infusion.The infusion system dead volume resides between the point where drug and inert carrier streams meet and the patient's blood. The dead volume is an often forgotten reservoir of drugs, especially when infusion flows slow or stop. Even with medications and carriers flowing, some mass of drug always resides within the dead volume. This reservoir of drug can be accidentally delivered into patients. When dose rate is changed, there can be a significant lag between intended and actual drug delivery. When a drug infusion is discontinued, drug delivery continues until the dead volume is fully cleared of residual drug by the carrier. When multiple drug infusions flow together, a change in any drug flow rate transiently affects the rate of delivery of all the others. For all of these reasons, the use of drug infusion systems with smaller dead volumes may be advantageous.For critically ill patients requiring multiple infusions, the obligate amount of administered fluid can contribute to volume overload. Recognition of the risk of overload has given rise to microinfusion strategies wherein drug solutions are highly concentrated and infused at low rates. However, potential risks associated with the dead volume may be magnified with microinfusion. All of these potential sources for adverse events relating to the infusion system dead volume illustrate the need for continuing education of clinical personnel in the complexities of drug delivery by infusion.This review concludes with an outline of future technologies for managing drug delivery by continuous infusion. Automated systems based on physiologic signals and smart systems based on physical principles and an understanding of dead volume may mitigate against adverse patient events and clinical errors in the complex process of drug delivery by infusion.

Effect of insulin infusion line on glycaemic variability in a perioperative high dependency unit (HDU): a prospective randomised controlled trial

BACKGROUND

Glucose control is an important issue in post-operative patients. The objective here was to compare two insulin infusion lines by syringe pumps to assess the impact of medical devices on glycaemic variability in surgical patients under intensive insulin therapy. This open, prospective, single-centre randomised study was conducted in a fifteen-bed perioperative high dependency unit (HDU) in a university hospital. In total, 172 eligible patients receiving insulin therapy agreed to participate in the study. Subcutaneous continuous glucose monitoring was set up for all patients and an optimised system with a dedicated insulin infusion line for half of the patients.

RESULTS

Eighty-six patients were infused via the optimised infusion line and 86 patients via the standard infusion line. No significant difference was found according to the glycaemic lability index score [mean difference between groups (95% CI): -0.09 (-0.34; 0.16), p = 0.49 after multiple imputation]. A glucose control monitoring system indicated a trend towards differences in the duration of hypoglycaemia (blood glucose level below 70 mg dl^-1 (3.9 mmol l^-1) over 1000 h of insulin infusion (9.7 ± 25.0 h in the standard group versus 4.4 ± 14.8 h in the optimised group, p = 0.059) and in the number of patients experiencing at least one hypoglycaemia incident (25.7 vs. 12.9%, p = 0.052). Time in the target range was similar for both groups.

CONCLUSIONS

The use of optimised infusion line with a dedicated insulin infusion line did not reduce glycaemic variability but minimised the incidence of hypoglycaemia events. The choice of the medical devices used to infuse insulin seems important for improving the safety of insulin infusion in perioperative HDU.