Arterial access in the pediatric emergency department

Lack of difference between continuous versus intermittent heparin infusion on maintenance of intra-arterial catheter in postoperative pediatric surgery: a randomized controlled study

OBJECTIVE:

To compare two systems of arterial catheters maintenance in postoperative pediatric surgery using intermittent or continuous infusion of heparin solution and to analyze adverse events related to the site of catheter insertion and the volume of infused heparin solution.

METHODS:

Randomized control trial with 140 patients selected for continuous infusion group (CIG) and intermittent infusion group (IIG). The variables analyzed were: type of heart disease, permanence time and size of the catheter, insertion site, technique used, volume of heparin solution and adverse events. The descriptive variables were analyzed by Student's t-test and the categorical variables, by chi-square test, being significant p<0.05.

RESULTS:

The median age was 11 (0-22) months, and 77 (55%) were females. No significant differences between studied variables were found, except for the volume used in CIG (12.0±1.2mL/24 hours) when compared to IIG (5.3±3.5mL/24 hours) with p<0.0003.

CONCLUSIONS:

The continuous infusion system and the intermittent infusion of heparin solution can be used for intra-arterial catheters maintenance in postoperative pediatric surgery, regardless of patient's clinical and demographic characteristics. Adverse events up to the third postoperative day occurred similarly in both groups. However, the intermittent infusion system usage in underweight children should be considered, due to the lower volume of infused heparin solution [ClinicalTrials.gov Identifier: NCT01097031].

Ultrasound for vascular access in pediatric patients

OBJECTIVES

In pediatric patients vascular access is often more difficult than in adults because of the smaller size of the vessels and the inability of the patient to cooperate without deep sedation or general anesthesia. Therefore Ultrasound has already become an invaluable tool for vascular access, but the full potential of ultrasound has yet to be fully realized. Improvements in image quality and a better understanding of optimal insertion techniques continue to help clinicians safely and efficiently place catheters with fewer complications.

METHODS AND TECHNIQUE

The probes used for the vascular access are mainly linear and convex type. Higher- frequency ultrasound provides a vivid image; however, the signals are remarkably attenuated. Therefore, the choice of the probe with appropriate frequency is essential. As blood vessels are relatively easily identified with ultrasound, ultrasound-guided vascular access does not require as sharp images as ultrasound-guided nerve block. For pediatric vascular access, the linear probe with 5-15 MHz, 2-5 cm depth is ideal and adequate for almost all cases. Ultrasound-guided vascular access has two main approaches: 'long-axis' or 'in-plane approach' and 'short-axis' or 'transverse approach'. The long-axis approach visualizes the vessel along the insertion pathway and is commonly used to monitor the entire approach of the needle into the vessel. The short-axis approach is easier to show the positional relationship and depth of target vessels, but it is much harder to follow the needle tip within the tissues.

CONCLUSION

The use of 'real-time' ultrasound has been shown to increase first insertion success, reduce access time, have a higher overall success, and reduce arterial puncture. As the technology continues to improve the use of ultrasound will become as ubiquitous as the lines themselves.

Catheterization of the radial or brachial artery in neonates and infants

BACKGROUND

In neonates and small children, percutaneous insertion of arterial catheters may be very difficult because of the small diameter of the arteries. Multiple attempts at cannulation are common and may be a predictor of serious adverse events following arterial cannulation. As an end artery, the brachial artery is usually not recommended for cannulation. However, limited data exist about brachial artery catheterization in neonates and young children. In this retrospective study, we report our experience with arterial indwelling catheters placed in neonates and small children prior to surgery for congenital heart defects.

METHODS

We reviewed 1473 patient medical files containing information about 1574 arterial lines for perioperative and intensive care monitoring. Patient data (age and weight), cannulation characteristics (site, type, percutaneous or cut down insertion), duration of catheterization and complications were documented using the anesthesia and/or intensive care unit files. Patients were divided into three groups according to body weight. Group I: patients with a bodyweight up to 5 kg (n = 561), group II: bodyweight 5-10 kg (n = 615), and group III: bodyweight 10-20 kg (n = 297).

RESULTS

The vast majority of our patients had radial or brachial artery catheterization. In group 1, we placed 200 brachial artery lines. Radial artery insertion was more successful with increasing body weight. Two 'cut downs' were necessary to place the arterial cannula (0.3%). The mean duration of the arterial cannula in place was 5.8 + 4.3 days in group I, which was significantly longer than in group III (2.9 + 2.2 days). Multiple attempts at catheter insertion were required for 200 patients in group I (P < 0.05 compared with groups II and III). The number of guide wires used was similar in all study groups. Generally, we preferred 24 and 22 G catheters for cannulation. Serious complications such as permanent ischemic damage were not observed. Temporary occlusion of an artery occurred in five of 1473 patients. The rate of local infection was 0.5% in group I, 0.7% in group II and 2.3% in group III. Local hematoma were observed more frequently, but with no relevant consequences. Most of our patients were cannulated on the right side. In group I, 112 brachial artery catheters were placed. The greater the weight, the more radial catheters were used compared with a brachial approach. The mean functional time of the catheters (5.8 +/- 4.3 days in group I) was significant shorter compared with patients from group III (2.9 +/- 2.2 days). In 33.3% (n = 200) multiple punctures were needed to place a catheter in group I (P < 0.05 compared with the other groups) whereas the use of a guide wire was evenly distributed throughout the study groups. Small catheters (24 and 22 G) were preferred for most patients. In total only eight 20 G sized catheters were used in the children of group III.

CONCLUSIONS

Even considering the nature of a retrospective study design, we conclude that the brachial artery could be considered for cannulation in neonates and small children.

Placement and complications of monitoring catheters

Vascular access is a necessary evil in critically ill patients, a population that is at high risk for complications. Appropriate planning and attention to detail minimize the associated risks while maximizing the benefits derived from catheter use.