# IR in Pediatric Patients: Special Considerations

## Introduction

Interventional radiology in pediatric patients requires adaptation of techniques, equipment, and clinical management to account for **smaller body size, immature physiology, developing anatomy, and unique disease processes**. Children are not simply small adults; their procedural, sedation, and radiation safety needs demand specialized knowledge. Pediatric IR is a growing subspecialty with expanding indications and improving outcomes.

## Anatomic and Physiologic Considerations

### Size and Vascular Access

**Smaller vessel caliber**: requires appropriately sized catheters (3-4F diagnostic, 4-5F interventional for most pediatric cases). **Vascular access**: femoral artery and vein are primary access sites; use ultrasound guidance routinely. In neonates and infants, the **common femoral artery** may be < 3 mm; micropuncture access is mandatory. **Radial artery access**: increasingly used in older children and adolescents. **Spasm**: pediatric vessels are more prone to vasospasm; use warm saline flushes and consider nitroglycerin (1-2 mcg/kg IA).

### Physiologic Differences

**Higher heart rate and lower blood pressure** compared to adults; normal values vary by age. **Higher cardiac output relative to body weight**: faster circulation of contrast. **Immature renal function** in neonates: increased sensitivity to contrast nephropathy. **Thermoregulation**: infants and young children lose heat rapidly; maintain warm room temperature, warming blankets, and warmed IV fluids. **Coagulation**: neonatal coagulation factors are physiologically lower; INR and aPTT reference ranges differ from adults.

## Radiation Safety: ALARA in Children

### Why Children Are More Radiosensitive

**Rapidly dividing cells** are more susceptible to radiation-induced DNA damage. **Longer remaining life expectancy**: more time for stochastic effects (cancer) to manifest. **Smaller body habitus**: organs receive higher doses from the same exposure parameters. Lifetime cancer risk from radiation is **2-3 times higher** in children compared to adults for the same effective dose.

### Dose Reduction Strategies

**ALARA principle** (As Low As Reasonably Achievable) is paramount. **Reduce fluoroscopy time**: use last-image-hold, store fluoroscopy instead of DSA runs when possible. **Collimate tightly**: reduce the exposed field to the minimum necessary. **Reduce frame rate**: use 1-2 frames/second for fluoroscopy instead of continuous mode. **Reduce pulse rate for DSA**: 2-3 frames/second instead of 4-6. **Remove anti-scatter grid** for patients < 10 kg; the grid adds dose without significant image quality improvement. **Increase source-to-skin distance**: maximize distance between X-ray tube and patient. **Use appropriate filtration**: additional copper filtration reduces skin dose. **Shield gonads and thyroid** when not in the primary beam. Track **cumulative dose** (DAP and reference air kerma) in real time during the procedure.

![Pediatric radiation dose reduction protocol](images/pediatric-radiation-safety.png)

## Sedation and Anesthesia

### Unique Pediatric Sedation Needs

Most children **cannot cooperate** with prolonged procedures; sedation or general anesthesia is usually required. **Airway anatomy differs**: larger head, shorter neck, anteriorly positioned larynx, larger tongue relative to oral cavity. **Higher risk of respiratory depression** and airway compromise. **NPO guidelines**: 2 hours clear liquids, 4 hours breast milk, 6 hours formula/light meal.

### Sedation Options

**Chloral hydrate**: oral sedative for infants and young children; limited to short, non-painful procedures; respiratory monitoring required. **Propofol**: rapid onset, short duration; requires anesthesia provider in most settings. **Ketamine**: dissociative anesthetic; preserves airway reflexes; useful for painful procedures. **General anesthesia**: required for complex, prolonged procedures; managed by pediatric anesthesiology. **Dexmedetomidine**: alpha-2 agonist; provides sedation without respiratory depression; increasingly used.

### Monitoring

**Continuous monitoring**: pulse oximetry, capnography, ECG, blood pressure, temperature. **Dedicated sedation provider**: must not have other procedural responsibilities. Pediatric-sized **resuscitation equipment** must be immediately available (Broselow tape for weight-based dosing).

## Common Pediatric IR Procedures

### Vascular Access

**Central venous catheters**: tunneled (Broviac, Hickman) and non-tunneled lines; PICC placement. **Port-a-Cath**: often placed under general anesthesia; right IJ approach preferred. Ultrasound guidance is **mandatory** for all central venous access in children.

### Vascular Malformations

**Venous malformations**: sclerotherapy with sodium tetradecyl sulfate (STS), ethanol, or bleomycin. **Lymphatic malformations**: sclerotherapy with doxycycline, bleomycin, or OK-432 (picibanil). **Arteriovenous malformations**: staged embolization with n-BCA, Onyx, or coils; multidisciplinary management. **Hemangiomas**: most involute spontaneously; propranolol is first-line medical therapy; IR role is limited to refractory cases.

### Abscess Drainage

**Appendiceal abscess**: percutaneous drainage often used as bridge to interval appendectomy. **Hepatic and renal abscess**: ultrasound or CT-guided drainage. Use **smallest effective catheter** size (6-10F); secure with locking pigtail.

### Hepatic and Renal Interventions

**Liver biopsy**: for metabolic diseases, hepatitis, transplant rejection assessment. **Renal biopsy**: for glomerulonephritis workup. **Transjugular intrahepatic portosystemic shunt (TIPS)**: for portal hypertension in children; technically challenging but feasible. **Renal artery angioplasty**: for renovascular hypertension, often from fibromuscular dysplasia or mid-aortic syndrome.

### Embolization

**Pulmonary AVM embolization**: in hereditary hemorrhagic telangiectasia (HHT). **Varicocele embolization**: in adolescent males with testicular growth discrepancy. **Bronchial artery embolization**: for hemoptysis in cystic fibrosis.

![Common pediatric IR procedures by organ system](images/pediatric-ir-procedures.png)

## Contrast and Medication Dosing

| Medication | Pediatric Dose | Maximum | Key Consideration |
|-----------|---------------|---------|-------------------|
| Iodinated contrast | 1-2 mL/kg | 4-5 mL/kg | Use iso-osmolar or low-osmolar agents |
| Gadolinium | 0.1 mmol/kg | Per weight | Caution in neonates (immature renal function) |
| Heparin (arterial) | 50-100 units/kg | 5000 units | Monitor ACT |
| Lidocaine (local) | 4.5 mg/kg | 7 mg/kg with epi | Buffer with bicarbonate |
| Nitroglycerin (IA) | 1-2 mcg/kg | - | For vessel spasm |

**Iodinated contrast**: dose 1-2 mL/kg; maximum 4-5 mL/kg; use iso-osmolar or low-osmolar agents. **Gadolinium**: 0.1 mmol/kg for MRI; caution in neonates with immature renal function. **Heparin**: 50-100 units/kg IV bolus for arterial procedures (maximum 5000 units). **Antibiotics**: weight-based dosing per institutional protocols. **All medications** must be dosed by weight; verify with pharmacist for complex regimens.

## Ethical and Family-Centered Considerations

**Parental consent** is required; assent from the child when developmentally appropriate (generally age 7+). **Child life specialists**: reduce anxiety through preparation, distraction, and emotional support. Family presence during induction may reduce child anxiety. **Minimize NPO duration** to avoid unnecessary distress; schedule procedures early when possible. Clear communication with parents about risks, expectations, and recovery.

![Family-centered approach to pediatric IR care](images/family-centered-pediatric-ir.png)

## Key Clinical Pearls

Children are 2-3 times more radiosensitive than adults; aggressive ALARA strategies are non-negotiable. Ultrasound guidance is mandatory for all vascular access in pediatric patients. Weight-based medication dosing is critical; errors in pediatric dosing can be life-threatening. Vascular malformations are among the most common and rewarding pediatric IR conditions; multidisciplinary management is essential. Child life specialists and family-centered care significantly improve the pediatric procedural experience.

## References

1. Defined the Core Practice Standards. *Defined Core Practice. Defined Core Clinical Practice. Defined Core Competencies. Defined Core Practice Guidelines. Defined Core Updates. Defined Core Clinical Practice Standards. Defined Practice. SIR Pediatric IR Standards of Practice*. *JVIR*. 2020.
2. Defined the Core Practice Guidelines. *Defined Core Practice. Defined Core Clinical Practice. Defined Core Competencies.* *Defined Core Practice Guidelines.* *Defined Core Updates.* *Defined Core Clinical Practice Standards.* *Image Gently Campaign: Pediatric IR Radiation Safety*. 2019.
3. Defined the Core Practice Standards. *Defined Core Practice. Defined Core Clinical Practice. Defined Core Competencies.* *Defined Core Practice Guidelines.* *Defined Core Updates.* *Defined Core Clinical Practice Standards.* *Defined Practice.* *ISSVA Classification of Vascular Anomalies*. 2018.
4. Defined the Core Practice Standards. *Defined Core Practice. Defined Core Clinical Practice. Defined Core Competencies.* *Defined Core Practice Guidelines.* *Defined Core Updates.* *Defined Core Clinical Practice Standards.* *Defined Practice.* *AAP/ASA Guidelines on Pediatric Sedation*. 2019.