Mark D. Weber

Peripheral arterial catheters are frequently used in critical care for continuous hemodynamic monitoring and arterial blood gas sampling. Prior work suggests that a lower catheter-to-vessel ratio (CVR) <40% may help preserve distal cannulated-artery perfusion. However, in pediatrics many arterial line injuries occur proximal to the cannulation site, which may be related to obstructed flow. To assess this obstruction, Doppler peak systolic velocity (PSV) alone may not reflect volumetric flow, particularly when the catheter occupies a large percentage of the lumen. We present a hypothesis-generating case series of five pediatric intensive care patients with indwelling radial arterial catheters and a CVR 50%–70%. Doppler PSV and flow volume (FV) were measured in the cannulated radial artery proximal to the catheter tip and compared to the ipsilateral ulnar artery. Radial-to-ulnar PSV ratios were higher in all patients (0.49–0.91) compared with radial-to-ulnar FV ratios (0.03–0.37). Differences between PSV and FV ratios within individual patients ranged from 0.12 to 0.80, suggesting that FV may provide complementary information about proximal arterial flow in high-CVR situations. Larger studies incorporating pre-cannulation assessments and patient outcomes are needed to determine the clinical significance of these Doppler findings.

Background: The effect of catheter size on distal arterial flow and measured arterial pressure remains underexplored. This study evaluates the relationship between catheter-to-vessel ratio (CVR), distal arterial flow, and measured blood pressures in a controlled pulsatile arterial vessel phantom. Methods: Using in vitro data simulating arterial conditions, distal peak systolic velocity, systolic (SBP), and diastolic (DBP) were analyzed across varying catheter sizes and vessel diameters. Pearson correlation and linear regression were used to assess the relationship between CVR and changes in relative distal velocity, SBP, and DBP. Results: Relative distal peak systolic velocity exhibited a strong inverse relationship with CVR ( r = −0.903, p < 0.001), with linear regression indicating that for every 10% increase in CVR, distal peak systolic velocity decreased by approximately 9.3%. Flow reduced >20% when CVR exceeded 0.6 and r = 0.88, p < 0.001). SBP increased by approximately 2.8% for every 10% increase in CVR. SBP increased by >10 mmHg when CVR exceeded 0.6 and r = 0.13, p = .61). Conclusions: Higher CVR in an in vitro model is associated with reduced distal flow and elevated systolic blood pressure in a phantom model. A CVR <0.4 (40%) appears to minimize flow and pressure changes. Appropriate selection of arterial catheter diameter for patient care may reduce risk of arterial catheter injuries and improve accuracy of clinical data.

Objective: Fluid overload (FO) after pediatric septic shock resuscitation increases the risk of secondary organ failure and long-term morbidity. We hypothesized that early hemodynamic point-of-care ultrasound (hPOCUS) use in pediatric septic shock would be associated with decreased FO. Methods: Retrospective, observational study between 2015 and 2018 in a large academic Pediatric Intensive Care Unit (PICU) of children < 18 years receiving ≥ 40 mL/kg of bolus fluids or vasoactive infusion for treatment of septic shock. %FO and severe FO (%FO ≥ 15%) at 72 h after shock onset were compared between children with hPOCUS exposure < 6 h after shock onset and those without. %FO was calculated: [(fluid in – out)/weight on PICU admission]*100. The association between hPOCUS < 6 h after septic shock onset and %FO and severe FO were evaluated. Results: Of 591 children included, 115 (19.4%) had hPOCUS within 6 h. Children with early hPOCUS vs. without had higher PIM-3; median 4.3, IQR 2.9–9.4 vs. 3.2, IQR 0.9–5.7, p = 0.0012. %FO was not significantly different in the early hPOCUS group, median difference -1.6%, 95% CI -3.2 to 0.03, p = 0.06. After controlling for confounders, %FO was significantly lower in the early hPOCUS group, ß-coefficient= -2.76, 95% CI -4.7 to -0.6, p = 0.012. Those with early hPOCUS had lower occurrence of severe FO 11.3% vs. 22.9%, p = 0.006; adjusted OR 0.41, 95% CI 0.22 to 0.76, p = 0.005. Conclusions: Early hPOCUS assessment during septic shock resuscitation was independently associated with decreased FO. Prospective research is needed to optimize hPOCUS use in pediatric septic shock management.

OBJECTIVES: To define and reduce the incidence of severe arterial catheter-associated proximal ischemic injuries (ACAPII). DESIGN: Quality improvement (QI) initiative. SETTING: University affiliated PICU in a quaternary children’s hospital. PATIENTS: All patients with indwelling arterial catheters (ACs) in the PICU at the Children’s Hospital of Philadelphia from January 2020 to December 2022. INTERVENTIONS: Phase I (January 2021 to December 2021) included defining ACAPII and daily rounding on all ACs by a dedicated PICU-specific vascular access team. Phase II (January 2022 to December 2022) introduced standardized recommendations and interventions including the use of topical nitroglycerin ointment (TNG) as a therapeutic option for mild injuries. MEASUREMENTS AND MAIN RESULTS: From January 2021 to December 2022, the rounding team evaluated 1916 ACs for a total of 5793 rounding episodes (line-days). During phase I, the overall number of ACAPII increased compared with prior year pre-QI (35 vs. 11, 318%). During phase II, the administration of TNG was associated with an increase in arterial line-days per AC in patients with mild injury (6.58 line-days per line, 158 d/24 lines) compared with pre-QI, phase I, and phase II mild injuries without use of TNG (3.27, 198/61; incident rate difference [95% CI], 3.31 [2.11–4.51]; p < 0.001). Special cause indicators shifted centerline from a weighted average 33.0–342.3 line-days between severe injuries. The cumulative severe ACAPII incidence rate decreased from its peak early in phase I (April 2021: 5.65 per 1000 line-days) to the end of phase II (December 2022: 2.11 per 1000 line-days). The overall rate of arterial line-days per AC during phase II increased compared with pre-QI (p < 0.01) and phase I (p < 0.01) CONCLUSIONS: The development of a newly defined measurable harm index, ACAPII, and implementation of increased surveillance resulted in increased awareness and reduction of severe injury as measured by rates and line-days between severe injuries in our critically ill patients. Protocolized management during phase II, including introducing TNG as a therapeutic option, resulted in increased AC line-days per catheter with sustained reduction in severe ACAPII rates.

OBJECTIVES: Ethanol lock therapy (ELT) is a potential method of central catheter salvage following central line-associated bloodstream infection (CLABSI) although there is potential risk of catheter damage in polyurethane catheters. Further, there is limited efficacy data across the spectrum of common pediatric catheters, and published ELT protocols describe dwell times that are not feasible for critically ill children. We sought to evaluate the safety and efficacy of ELT in polyurethane catheters using brief (30 min to 2 hr) dwell times in our PICU. DESIGN: Investigational pilot study using historical control data. SETTING: PICU in quaternary care, free-standing children’s hospital. INTERVENTIONS: ELT in polyurethane central venous catheters for catheter salvage. RESULTS: ELT with brief dwell times was used in 25 patients, 22 of whom were bacteremic. Ultimately 11 patients, comprising 14 catheters, were diagnosed with a primary CLABSI. The catheter salvage rate in primary CLABSI patients receiving ELT was 92% (13/14) and significantly higher than the salvage rate in patients receiving antibiotics alone (non-ELT) (62%, 39/64; mean difference 0.32, 95% CI [0.14–0.50], p = 0.03). The rate of catheter fracture in all patients receiving ELT was 8% (2/25) while the rate of fracture in the non-ELT group was 13% (8/64; mean difference –0.05, 95% CI [–0.18 to 0.09], p = 0.72). The rate of tissue plasminogen activator (tPA) use in the ELT group was 8% (2/25), whereas the rate of tPA use in the non-ELT group was significantly higher at 42% (26/64; mean difference –0.34, 95% CI [–0.49 to –0.17], p = 0.002). CONCLUSIONS: The use of ELT for catheter salvage and prophylaxis in the PICU is safe in a variety of polyurethane catheters. Dwell times ranging from 30 minutes to 2 hours were effective in sterilizing the catheters while allowing other therapies to continue. This approach may decrease the need for frequent line changes in a medically fragile pediatric population.

Background: Pediatric patients requiring extracorporeal life support (ECLS) often need central venous access for extended periods of time. In this population, the placement of an upper extremity peripherally inserted central catheter (PICC) can be challenging due to the location and size of the venous ECLS cannula. Bedside placement of a tunneled femorally inserted central catheters (T-FICC) can be a viable alternative to a traditional PICC. Methods: In this case series we present five children who were on ECLS and had a T-FICC placed at the bedside. Results: In this series of five patients we successfully placed T-FICCs while the patients were on ECLS. The T-FICCs dwelled from 15 to 182 days. There were no events of central line associated blood stream infections or deep vein thrombosis. There was only one unintentional line dislodgement noted. Conclusion: The use of T-FICCs placed at the bedside is a safe and reliable alternative for secure long-term venous access in children who are on ECLS.