Overview
Definition:
Peripheral intravenous (IV) access is crucial for fluid, medication, and blood product administration
Difficult vascular access (DVA) in pediatric patients, especially neonates and infants, poses significant challenges due to smaller vessel size, obesity, dehydration, or repeated cannulation attempts
Ultrasound guidance (USG) has emerged as a valuable tool to improve first-attempt success rates and reduce complications associated with PIV insertion in these challenging scenarios.
Epidemiology:
The incidence of difficult vascular access in pediatric patients varies widely, with some studies reporting up to 50% of neonates and infants requiring multiple attempts for peripheral venous cannulation
Factors contributing to DVA include prematurity, prematurity-related complications, dehydration, obesity, darker skin pigmentation, and chronic medical conditions requiring frequent IV access.
Clinical Significance:
Successful and timely peripheral IV access is vital for effective management of critically ill pediatric patients, including resuscitation, antibiotic administration, analgesia, and nutritional support
Failed attempts can lead to increased patient distress, prolonged procedural time, multiple venipunctures, increased risk of complications like hematoma, nerve injury, and infection, and delayed treatment
Ultrasound guidance significantly enhances the ability of clinicians to achieve successful PIV access in these challenging cases, thereby improving patient outcomes and reducing healthcare costs.
Age Considerations
Neonate:
Smaller vein diameter, fragile vessels, limited tissue depth, increased risk of extravasation
Use of high-frequency linear transducers is essential
Careful attention to sterile technique is paramount.
Infant:
Larger vessel size compared to neonates but still challenging due to movement and limited peripheral veins
May use slightly lower frequency transducers if tissue depth is greater
Arm and leg veins are common sites.
Child:
Veins are generally more easily visualized, but obesity or dehydration can still pose challenges
Dynamic real-time imaging is still beneficial for confirming vessel patency and guiding the needle.
Factors Influencing Access:
Dehydration, obesity, previous IV lines, edema, dark skin pigmentation, and patient anxiety/movement.
Diagnostic Approach
History Taking:
Inquire about previous IV access difficulties, duration of illness, fluid intake and output, presence of vomiting or diarrhea, and current medications
Assess for signs of dehydration or edema
Ascertain previous successful or unsuccessful IV sites.
Physical Examination:
Assess skin turgor, mucous membrane moisture, and capillary refill time to evaluate hydration status
Examine peripheral veins visually and by palpation, noting any distension, tortuosity, or absence
Evaluate for edema or hematoma from previous attempts
Assess body mass index for potential obesity challenges.
Ultrasound Technique:
Use a high-frequency linear transducer (e.g., 10-15 MHz)
Apply sterile gel and cover the probe with a sterile sheath and glove
Orient the probe in a longitudinal plane over the suspected vessel
Identify veins based on anechoic, compressible, pulsatile (artery) or non-pulsatile (vein) tubular structures
Evaluate for thrombus, anatomical variation, and surrounding structures
Dynamic assessment: compress the vessel to confirm compressibility and patency.
Imaging Modalities:
High-resolution ultrasound imaging is the primary modality for real-time visualization of peripheral veins
Avoidance of Doppler unless specifically assessing flow in complex cases, as it can obscure direct visualization of the needle tip.
Management
Initial Preparation:
Ensure adequate lighting, necessary equipment (IV catheters of appropriate size, syringes, sterile gel, sterile probe cover, sterile gloves, antiseptic solution, dressing), and a calm environment
Sedation or topical anesthetic may be considered for older children or anxious patients.
Ultrasound Guided Insertion Technique:
Place the probe in a longitudinal plane over the target vein
Identify the vein and surrounding structures
Insert the IV catheter at a 30-45 degree angle, visualizing the needle tip in real-time under ultrasound guidance
Advance the needle slowly, maintaining visualization
Once the needle enters the lumen, flashback of blood should be observed
Advance the catheter while withdrawing the needle
Secure the IV line with appropriate dressing.
Catheter Selection:
Select the smallest gauge catheter that can deliver the required therapy, typically 24-28 gauge for neonates and infants, and 20-24 gauge for older children
Use appropriate length catheters to minimize manipulation.
Site Selection:
Common sites include antecubital fossa, forearm, hand dorsum, saphenous vein (medial malleolus area), and foot dorsum
Ultrasound can identify veins not apparent on physical examination.
Alternatives If Failed:
If peripheral access remains elusive after multiple ultrasound-guided attempts, consider central venous access (if indicated and expertise is available) or intraosseous access as an alternative.
Complications
Early Complications:
Hematoma formation
Pain
Nerve injury
Artery puncture
Incomplete insertion or dislodgement
Extravasation of infusate
Phlebitis.
Late Complications:
Infection (local or systemic)
Occlusion of the vein
Thrombosis
Catheter-related bloodstream infection (CRBSI).
Prevention Strategies:
Utilize ultrasound guidance to minimize venipuncture attempts
Employ proper sterile technique
Select appropriate catheter size
Secure the IV line adequately
Monitor the IV site regularly for signs of complications
Educate nursing staff on early detection and management of complications.
Prognosis
Factors Affecting Prognosis:
The prognosis for successful peripheral IV access using ultrasound guidance in difficult cases is generally excellent
Factors influencing success include operator experience, ultrasound equipment quality, patient factors (e.g., degree of dehydration, obesity), and timely utilization of the technique.
Outcomes With Ultrasound Guidance:
Studies consistently demonstrate higher first-attempt success rates, fewer venipunctures, reduced procedure time, and decreased patient and caregiver distress when ultrasound guidance is used for PIV insertion in difficult access pediatric patients
This translates to more efficient care and improved patient experience.
Follow Up:
Routine monitoring of the IV site for signs of infiltration, infection, or phlebitis is essential throughout the duration of therapy
Prompt removal of the IV catheter once therapy is complete or if complications arise.
Key Points
Exam Focus:
Understand the indications for ultrasound guidance in pediatric IV access
Be familiar with the specific ultrasound probe types and settings for neonates and infants
Recognize potential complications and their management
Differentiate between arterial and venous visualization on ultrasound.
Clinical Pearls:
Always use sterile technique with ultrasound probe covers
Start with a longitudinal view of the vessel
Compress the vein gently to confirm its nature and patency
Advance the needle tip slowly and steadily
Look for flashback of blood *after* the needle enters the lumen
Consider topical anesthetics or mild sedation for very distressed children.
Common Mistakes:
Using inappropriate transducer frequency or probe cover
Inadequate visualization of the needle tip
Attempting insertion without proper sterile technique
Misinterpreting arterial pulsations as venous flashback
Failing to stop advancing the catheter once flashback is achieved.