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Feeding Tubes: Types, Structure, Parts, and How They Work

Routes for enteral and parenteral nutrition delivery, showing nasogastric/duodenal/jejunal tube, gastrostomy tube, and jejunostomy tube

Figure: Routes available for delivery of artificial nutritional support - Bailey & Love's Surgery, 28th Ed.

What Is a Feeding Tube?

A feeding tube is a flexible medical device inserted into the gastrointestinal (GI) tract to deliver nutrition, fluids, and medications to patients who cannot maintain adequate oral intake. Enteral nutrition (via the gut) is always preferred over parenteral (intravenous) nutrition because it preserves the gut mucosal barrier, maintains gut immunity, prevents gut atrophy, reduces infection rates, improves wound healing, and shortens hospital stays. - Bailey & Love's Surgery, p. 357

Feed formulations typically contain 1-2 kcal/mL and up to 0.6 g/mL protein, with variable fat, nitrogen, and osmolarity content.

Classification: How Tubes Are Categorized

Feeding tubes are classified in two ways:

1. By Entry Site (where the tube enters the body):

Nasal route - through the nostril (nares)
Abdominal route - directly through the abdominal wall (ostomy)

2. By Tip Location (where the tube ends inside the body):

Stomach (gastric) - nasogastric (NG) tube, gastrostomy (G/PEG) tube
Duodenum - nasoduodenal tube
Jejunum (small intestine) - nasojejunal (NJ) tube, jejunostomy (J) tube
Both stomach and jejunum - PEG-J tube (dual lumen)
Roberts & Hedges' Clinical Procedures in Emergency Medicine, p. 968-970

Major Types in Detail

1. Nasogastric (NG) Tube

The most common type. Inserted through the nose, travels down the esophagus, and ends in the stomach.

Two main designs:

A. Levin Tube (single-lumen)

Firm, straight, single-lumen construction
Multiple distal side ports (openings near the tip) for drainage/aspiration
Used primarily for gastric aspiration, lavage, and short-term feeding
Limitation: the lumen can become occluded by gastric mucosa when suction is applied, potentially damaging mucosa

B. Salem Sump Tube (double-lumen)

Two lumens running side by side:
- Main lumen (large): for suction, feeding, medication delivery
- Vent lumen (small, blue "pigtail"): provides a constant low-level airflow into the stomach, preventing the main lumen from being blocked by mucosa
Multiple distal side ports
Antireflux valves available for the vent to prevent back-leakage
Proximal multiport adapters allow the same tube to be used for feeding, irrigating, suctioning, or medicating
Material: clear radiopaque polypropylene or silicone

Salem Sump (double-lumen) NG tube - the clear main tube with the blue vent lumen visible

Salem Sump tube - note the blue vent lumen running alongside the main clear lumen

C. Fine-Bore Feeding Tube (e.g., Dobhoff, Entri-Flex)

Specifically designed for long-term enteral feeding:

Made of soft polyurethane or silicone (becomes even softer at body temperature)
Very small diameter - comfortable for prolonged use
Tungsten-weighted tip or balloon near the distal end - the weight helps the tube migrate past the pylorus into the duodenum/jejunum under gravity and peristalsis
Removable stylet/stiffening wire inserted before placement to give rigidity; removed after positioning is confirmed
Pre-applied lubricant on some models (activated with a 5 mL water flush)
Radiopaque - visible on X-ray to confirm placement
Designed to resist collapse when checking gastric residual

Fine-bore nasogastric feeding tube with weighted, radiopaque tip and stylet

Fine-bore feeding tube with weighted metal tip and stylet visible at the distal end; proximal end has a locking feed port

Pfenninger & Fowler's Procedures for Primary Care, p. 1420-1421

2. Nasojejunal (NJ) Tube / Nasoduodenal Tube

Same construction as the fine-bore feeding tube but positioned beyond the pylorus into the jejunum (or duodenum)
The weighted tip and gravity, combined with peristalsis and right-decubitus positioning, facilitate passage
Metoclopramide (10 mg IV) or erythromycin (3 mg/kg IV) can be used to aid passage past the pylorus
May require endoscopic or fluoroscopic guidance if positioning fails

Why feed into the jejunum? Jejunal feeding reduces gastroesophageal reflux and aspiration risk. Normally ~20% of gastric antral contents pass into the duodenum with 80% refluxing back - positioning the tube tip in the mid-jejunum (not just the proximal duodenum) is needed to meaningfully reduce aspiration risk.

3. Percutaneous Endoscopic Gastrostomy (PEG) Tube

For long-term feeding (>4 weeks) when the stomach is directly accessed through the abdominal wall.

Structural parts:

Part	Description
External bumper/flange	Flat disc on the outside of the abdominal wall; prevents the tube from slipping inward
Tube body	Flexible silicone or polyurethane shaft passing through the abdominal wall into the stomach
Internal retention device	Either a mushroom/de Pezzer head (original PEG) that deforms to pass through the tract or a balloon (filled with water, 3-10 mL) that holds the tube against the stomach wall
Feeding port	Proximal opening for attaching the feeding set
Medication/irrigation port	Separate port on some models
Balloon inflation port	On balloon-type tubes; used to inflate/deflate the internal balloon

Placement: Done endoscopically under local anesthesia and sedation - no surgical incision required. - Roberts & Hedges', p. 968

Original vs. Replacement tubes:

Original PEG = mushroom head (non-balloon) - requires traction/countertraction or endoscopic removal
Replacement PEG = balloon-type - much easier to change; simply deflate the balloon and slide out

PEG tube types showing mushroom head (original) vs balloon-type replacement

PEG tubes: upper = balloon-type replacement; lower = original mushroom-head type

4. PEG-J Tube (Gastro-Jejunal)

A single entry through the stomach wall (like a PEG) but the inner tube extends through the pylorus into the jejunum
Has two separate lumens - one for gastric venting/decompression and one for jejunal feeding
Used when gastric feeding is not tolerated (gastroparesis, severe reflux)

5. Surgical Jejunostomy (J-Tube)

Inserted directly through the abdominal wall into the small bowel (not via the stomach)
Requires a surgical incision under general anesthesia - results in a surgical scar at the insertion site
Used when the stomach is inaccessible or must be bypassed (e.g., after gastrectomy)
Reduces aspiration compared to gastric feeding but tolerance can be lower (diarrhea risk)

Structural Parts Common to All Feeding Tubes

Component	Function
Tube body	Flexible conduit made of polyurethane, silicone, or PVC; the shaft through which feed travels
Distal tip	Sits inside the target organ (stomach/jejunum); may be open-ended or have side ports
Side ports/eyes	Small openings near the tip for drainage or infusion; spread flow to reduce mucosal trauma
Weighted tip (fine-bore)	Tungsten or mercury weight aids gravitational passage into the small bowel
Stylet/guidewire	Temporary stiffening wire inserted through the lumen during placement; removed before use
Proximal connector/port	Standardized fitting (ENFit or legacy) that connects to feeding sets, syringes, or pumps
Feed clamp	Clamps the tube to stop flow when not feeding
External fixator/nose clip	Secures the tube to the nose (nasal tubes) or abdominal wall (transabdominal tubes)
Centimeter markings	Depth markings on the tube to confirm correct placement depth
Radiopaque stripe	Embedded barium or radiopaque material to make the tube visible on X-ray

How It Works: The Feeding Process

Placement - The tube is passed through the nose (or abdominal wall) and advanced to the target site
Placement confirmation - Chest/abdominal X-ray is mandatory before starting feeds; auscultation alone is unreliable and can be misleading
Feed initiation - Feeding typically starts at 10-20 mL/hour and is increased gradually to prevent refeeding syndrome in malnourished patients
Delivery method - Feed is delivered via:
- Gravity drip - feed bag hung above patient
- Enteral pump - programmable pump controls rate precisely
- Bolus feeding - syringe-driven bolus over 15-30 min (mimics meal timing; used for stable patients at home)
Gastric digestion - Gastric feeding allows normal stomach acid, enzyme mixing, and incremental delivery to the small bowel. Gastric feeding produces better overall digestion than intestinal feeding
Residual checks - Gastric residual volume is periodically aspirated to check for delayed gastric emptying and aspiration risk

Indications at a Glance

Tube Type	Route	Indication
NG (Levin/Salem)	Nasal → Stomach	Short-term decompression, lavage, feeding
Fine-bore NG	Nasal → Stomach	Short-to-medium-term enteral feeding
NJ / Nasoduodenal	Nasal → Jejunum	High aspiration risk, gastroparesis
PEG	Abdominal → Stomach	Long-term feeding (>4 weeks), dysphagia
PEG-J	Abdominal → Jejunum	Gastric intolerance + long-term feeding
Surgical J-tube	Abdominal → Jejunum	Post-gastrectomy, stomach not available

Key Contraindications

NG tube contraindications: Skull base fractures (risk of intracranial placement), severe coagulopathy, esophagogastric surgery/perforation, distal bowel obstruction.

PEG tube contraindications: Interposed organs (liver, colon), portal hypertension/varices, ascites, peritoneal metastasis, gastroparesis, gastric outlet obstruction, esophagogastric surgery, limited life expectancy, patient refusal.

Scott-Brown's Otorhinolaryngology, p. 9025-9086

Common Complications

Pulmonary misplacement - the most dangerous; tube passes into the trachea/bronchus instead of the esophagus (especially in obtunded patients)
Esophageal coiling - tube fails to advance; coils in pharynx or esophagus
Aspiration - feed entering the airway, especially with gastric feeding
Tube occlusion - lumen blocked by feed residue or medications
Refeeding syndrome - electrolyte shifts (hypokalemia, hypophosphatemia, hypomagnesemia) when feeding is started too quickly in malnourished patients
Diarrhea - more common with jejunal feeding or hyperosmolar feeds

Sources:

Roberts & Hedges' Clinical Procedures in Emergency Medicine, Chapter 40
Pfenninger & Fowler's Procedures for Primary Care, Chapter 203
Bailey & Love's Short Practice of Surgery, 28th Ed., Chapter 25
Scott-Brown's Otorhinolaryngology Head & Neck Surgery, Chapter on Enteral Tube Feeding

Feeding tube in paediatric

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Feeding Tubes in Paediatrics

Why Paediatrics Is Different

Children are not simply small adults. Several anatomical, physiological, and developmental factors make paediatric tube feeding a distinct clinical domain:

Smaller anatomy - nasal passages, nostrils, and GI tract are proportionally much smaller and more easily injured
Larger tonsils, adenoids, and tongue relative to airway size, which can obstruct tube passage and increase bleeding risk during insertion
Developing feeding skills - premature infants and neonates have not yet developed coordinated sucking and swallowing, making oral feeding temporarily impossible
Higher caloric demands per kg - growing children need far more calories per kilogram than adults
Different disease spectrum - indications include prematurity, congenital anomalies, failure to thrive, and craniofacial abnormalities that are unique to paediatrics
Psychosocial impact - tube feeding affects bonding, oral feeding skill development, and quality of life for both child and family
Pfenninger & Fowler's Procedures for Primary Care, p. 1421; Schwartz's Principles of Surgery, 11th Ed.

Anatomy Relevant to Paediatric NG Tube Insertion

Sagittal anatomy of the nasal cavity, pharynx and upper airways - showing the path a feeding tube travels

Pharyngeal anatomy. The tube passes through the inferior meatus of the nasal cavity, past the nasopharynx, down the esophagus (posterior to the trachea) into the stomach.

Horizontal insertion of the nasogastric tube through the nasal cavity - the tube passes along the floor of the nasal cavity

Correct insertion direction: horizontally along the floor of the nasal cavity, not upward.

The tube follows this path: Nostril → nasal floor (inferior meatus) → nasopharynx → oropharynx → esophagus → stomach (or jejunum)

In children, the key anatomical differences are:

Larger pharyngeal tonsils (adenoids) and palatine tonsils narrow the nasopharyngeal passage
The tongue is proportionally large and may push into the oropharynx
Soft tissues are easily injured, making hemorrhage a more significant risk
Limiting tube size to match the smallest nostril dimension is essential

Tube Sizing in Paediatrics

Tube size is measured in French (Fr) gauge - the larger the number, the wider the tube.

Patient Group	Recommended NG Tube Size
Adults	16-18 Fr (Salem sump)
Children	10 Fr
Nasoenteric feeding tubes (all ages)	5-12 Fr (fine-bore)
Premature/small neonates	5-6 Fr (ultra fine-bore)

Smaller tubes (5-8 Fr) are more comfortable and less likely to become occluded - preferred for prolonged feeding
Larger tubes (12 Fr) should only be used short-term as they are more uncomfortable and more prone to blockage
Tube length must also be proportionally shorter - the insertion depth is estimated by measuring from the ear to the nose, then extending to 6 inches below the xiphoid (or 8-10 inches for nasoenteric tubes)
Pfenninger & Fowler's, p. 1422

Types of Feeding Tubes Used in Paediatrics

1. Nasogastric (NG) Tube

The most common type in children. Passes through the nose into the stomach.

Uses in paediatrics:

Premature neonates who cannot coordinate suck-swallow
Short-term supplemental feeding (illness, post-surgery)
Gastric decompression (bowel obstruction, ileus)
Drug/formula administration
Gastric lavage (poisoning)

Key features for children:

Fine-bore silicone or polyurethane preferred for comfort
10 Fr as standard for children (vs 16-18 Fr for adults)
Orogastric (OG) route - through the mouth - is preferred in neonates who are obligate nasal breathers, as an NG tube can significantly obstruct airflow through their narrow nasal passages

2. Orogastric (OG) Tube

Passed through the mouth into the stomach
Preferred in neonates and young infants (obligate nasal breathers) where nasal obstruction by an NG tube could cause respiratory compromise
Also safer when nasal route is contraindicated (choanal atresia, skull base fractures)
Less comfortable for conscious older children, so less used beyond the neonatal period

3. Nasojejunal (NJ) Tube

Fine-bore tube advanced past the pylorus into the jejunum
Used when gastric feeding is not tolerated (e.g., severe gastroparesis, high aspiration risk, severe reflux)
In children, position is usually confirmed by fluoroscopy
Reduces aspiration and reflux but requires more precise monitoring

4. Gastrostomy Tube (G-tube / PEG)

For long-term feeding (typically >4-6 weeks) when the nasal route is impractical or harmful.

Indications in paediatrics:

Neurological conditions (cerebral palsy, brain injury) with chronic dysphagia
Craniofacial anomalies (cleft palate, Pierre Robin sequence) impairing oral feeding
Congenital heart disease with high metabolic demand
Premature infants with prolonged feeding difficulties
Failure to thrive not resolving with NG feeding

Structure and parts (same as adult PEG but smaller gauge):

External bumper (skin disc) holds tube outside the abdomen
Tube body passes through abdominal wall into the stomach
Internal retention device: balloon type (easiest replacement) or mushroom/button type
Feeding port + medication port proximally

Balloon Gastrostomy Button ("Mickey Button"): A low-profile device sitting flush against the skin with no external tube - popular for children because it is less visible, less likely to be accidentally pulled, and allows greater physical activity. A separate extension set is attached at feeding times and detached afterward.

5. Jejunostomy (J-tube)

Tube enters the abdominal wall directly into the jejunum (bypasses the stomach entirely)
Used surgically after gastric procedures, severe gastroparesis, or when the stomach is unavailable
In the paediatric surgical neonate (e.g., gastroschisis, intestinal atresia, necrotizing enterocolitis), this is sometimes the only viable enteral route
Schwartz's Principles of Surgery, p. 1735-1736; Kaplan & Sadock's Psychiatry

Paediatric Indications for Tube Feeding

Clinical Situation	Preferred Tube
Premature neonate (<34 weeks), undeveloped suck	OG or NG (5-6 Fr)
Neurological dysphagia (cerebral palsy)	G-tube or PEG
Craniofacial anomalies (cleft palate, Pierre Robin)	NG short-term → G-tube
Congenital heart disease (high metabolic need)	NG or G-tube
Failure to thrive	NG or G-tube
Gastroschisis / intestinal atresia (post-op)	NJ or J-tube
Bowel obstruction / ileus (decompression)	NG
Gastric aspiration risk / severe reflux	NJ tube
Feeding disorder with behavioral component	NG short-term, specialist input

Schwartz's Surgery, p. 1735; Kaplan & Sadock's, p. 2563-2571

Nutritional Requirements by Age Group

This is critical in paediatrics - children have far higher caloric needs per kg than adults, and requirements change rapidly with growth:

Age	Calories (kcal/kg/day)	Protein (g/kg/day)
0-6 months	100-120	2.0
6 months-1 year	100	1.5
1-3 years	100	1.2
4-6 years	90	1.0
7-10 years	70	1.0
11-14 years	55	1.0
15-18 years	45	1.0

Schwartz's Principles of Surgery, Table 39-1, p. 1736

Feed Formulas in Paediatrics

Unlike adults (who receive standard 1-2 kcal/mL enteral formulas), children require age-specific formulas. Neonates, especially premature ones, have distinct needs:

Formula	kcal/mL	Protein (g/mL)	Fat (g/mL)	Carbohydrate (g/mL)
Human milk	0.67	0.011	0.040	0.070
Enfamil 20 (milk-based)	0.67	0.015	0.038	0.069
Similac 20 (milk-based)	0.67	0.015	0.036	0.072
Prosobee (soy-based)	0.67	0.020	0.036	0.070
Pregestimil (hydrolysed)	0.67	0.019	0.028	0.091
Alimentum (hydrolysed)	0.67	0.019	0.038	0.068
Enfamil Premature (preterm)	0.80	0.024	0.041	0.089

Premature formula (0.80 kcal/mL) is more calorie-dense because preterms need extra energy for catch-up growth and have limited gastric capacity
Hydrolysed formulas (Pregestimil, Alimentum) are used when the infant has malabsorption or cow's milk protein intolerance
Human milk is always preferred when available
Schwartz's Surgery, Table 39-2, p. 1736

Insertion Technique: Key Paediatric Differences

Measuring Insertion Depth

The standard adult measurement (nose to ear to xiphoid) is adapted for children. The estimated tube length at the nose:

NG tube: nose to ear + nose to xiphoid + 6 inches below xiphoid
The nasal septum to tracheoesophageal junction is about 8 inches in adults; this distance is proportionally shorter in children

Challenges in Children

No ability to cooperate (infants, young children) - ask the child to swallow; if they cannot, induce swallowing with a small amount of water in the mouth or through the tube
Restrain hands of young/uncooperative children to prevent tube removal
Never force - if significant resistance, respiratory distress, or nasal hemorrhage occurs, stop immediately and withdraw the tube
In intubated patients, tube passage may be the hardest; a second ET tube as a conduit can be used if oral route is needed

Confirming Placement

X-ray confirmation is mandatory before feeding begins - auscultation alone is unreliable
In neonatal units, pH testing of aspirate (pH <5.5 confirms gastric position) may be used to reduce radiation exposure, per local protocol
Check the carina level on CXR - a tracheally placed tube deviates sharply at the carina into the right or left bronchus

Complications Specific to Paediatrics

Complication	Paediatric Specifics
Pulmonary misplacement	More common in neonates with absent cough reflex; potentially fatal if formula infused into lung
Nasal hemorrhage	Higher risk due to proportionally large, soft, vascular nasal mucosa and adenoids
Tube coiling in oropharynx	More common in young children with large tongues and tonsils
Aspiration	Neonates at higher risk due to poor gag reflex and supine position
Refeeding syndrome	Risk in malnourished infants - start feeds slowly and monitor electrolytes (K⁺, PO₄, Mg²⁺)
TPN-associated cholestasis	Specific to neonates on prolonged parenteral nutrition - prevented by introducing even minimal enteral feeds as early as possible
Accidental decannulation	Children (especially toddlers) often pull tubes out - may need mittens or elbow restraints
Granulation tissue at G-tube site	Common in children with PEG/gastrostomy - treated with silver nitrate or topical steroids

When to Use Enteral vs. Parenteral Nutrition

In paediatric surgical patients, the principle is unambiguous: enteral nutrition is always preferred when the GI tract is functional, because it:

Promotes growth and function of the GI system
Ensures the infant continues to learn and develop oral feeding skills
Prevents parenteral nutrition-associated cholestasis (a major cause of liver failure in long-term TPN neonates)

Parenteral nutrition is used only when enteral feeding is mechanically, ischemically, or functionally impossible - and even then, minimal enteral (trophic) feeds should be started as early as possible to stimulate gut maturation.

Schwartz's Principles of Surgery, p. 1735

Summary Table: Adult vs. Paediatric Feeding Tube Comparison

Feature	Adult	Paediatric
Standard NG tube size	16-18 Fr	10 Fr
Fine-bore feeding tube	8-12 Fr	5-8 Fr
Preferred route in neonates	Nasal	Oral (orogastric)
Insertion cooperation	Usually possible	Often impossible; restraint may be needed
Caloric needs	25-35 kcal/kg/day	45-120 kcal/kg/day depending on age
Formula	Standard 1-2 kcal/mL	Age/condition-specific; premature formulas 0.8 kcal/mL
Long-term tube	PEG	PEG or gastrostomy button (Mickey button)
Key complication concern	Aspiration, misplacement	Misplacement, hemorrhage, oral feeding skill regression

Sources:

Pfenninger & Fowler's Procedures for Primary Care, 3rd Ed., Chapter 203
Schwartz's Principles of Surgery, 11th Ed., Chapter 39 (Pediatric Surgery)
Kaplan & Sadock's Comprehensive Textbook of Psychiatry (Feeding Disorders in Early Childhood)
Roberts & Hedges' Clinical Procedures in Emergency Medicine, Chapter 40

Foleys catheter details of different parts and its use also in paediatric uses

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Foley Catheter: Parts, Structure, and Use - Including Paediatric Applications

What Is a Foley Catheter?

A Foley catheter (also called an indwelling urethral catheter or retention catheter) is a flexible tube inserted through the urethra into the bladder to continuously drain urine. It is held in place by a small balloon inflated with water inside the bladder - this is the defining feature that distinguishes it from a simple straight catheter.

It was named after American urologist Frederic Foley, who designed the self-retaining balloon catheter in the 1930s.

Anatomy: The Path the Catheter Takes

Sagittal anatomy of the male pelvis showing the Foley catheter passing through the urethra, prostate, and into the bladder

A-F: Steps of urethral catheter insertion. C shows cross-section of male pelvis with catheter and balloon positioned inside the bladder. F shows balloon inflated and catheter gently withdrawn to seat balloon at bladder neck.

Male path: External urethral meatus → penile urethra → bulbar urethra → membranous urethra → prostatic urethra → bladder neck → bladder

Female path: External urethral meatus (shorter, ~4 cm) → urethra → bladder

Detailed Anatomy of a Foley Catheter: All Parts

External (Proximal) End - Outside the Patient

Part	Description
Funnel-shaped proximal end	The wide open end connecting to the drainage bag or syringe
Drainage port (main lumen port)	The large opening where urine drains out; connects via tubing to a urine collection bag
Balloon inflation port	A smaller, separate port (usually colour-coded, e.g., blue or red) used to inflate and deflate the retention balloon with sterile water using a syringe
Valve/self-sealing valve	On the inflation port; prevents water escaping after balloon is inflated
Third port (3-way catheters only)	Additional port for continuous bladder irrigation (e.g., post-TURP)
External clamp	Used to clamp the drainage lumen when needed

Tube Body (Shaft)

Feature	Detail
Material	Latex (standard), silicone (latex-free, for allergy), silicone-coated latex, hydrogel-coated (for long-term use)
Size	Measured in French (Fr) gauge - 1 Fr = 0.33 mm diameter
Length	~40 cm (standard); paediatric versions are shorter
Lumens	2-way (most common) or 3-way (for irrigation)
Centimetre markings	Depth markings along the shaft to confirm insertion depth
Radiopaque stripe	Embedded line visible on X-ray to confirm position

Internal (Distal) End - Inside the Bladder

Part	Description
Tip	Rounded, atraumatic tip that enters the bladder first
Drainage eye (side ports)	One or two openings just proximal to the balloon, through which urine enters the catheter lumen to drain
Retention balloon	Sits just above the tip; inflated after confirmed bladder entry; holds the catheter in place at the bladder neck. Standard sizes: 5 mL (paediatric) or 10-30 mL (adult)

Lumen Configurations

2-Way (Two-Lumen) Foley - Most Common

Port 1: Drainage lumen   → urine drains out
Port 2: Balloon lumen    → inflated to retain catheter

Used for: standard urinary drainage, urinary retention, monitoring urine output, post-op care, immobile patients.

3-Way (Three-Lumen) Foley

Port 1: Drainage lumen        → urine drains out
Port 2: Balloon lumen         → inflated to retain catheter
Port 3: Irrigation lumen      → sterile saline flows IN continuously

Used for: continuous bladder irrigation after transurethral resection of the prostate (TURP) or other bladder surgery, to prevent clot formation and maintain catheter patency.

Catheter Sizes: French Gauge Reference

French (Fr) Size	Outer Diameter	Common Use
5 Fr	1.7 mm	Neonates / premature infants
6 Fr	2.0 mm	Neonates / small infants
8 Fr	2.7 mm	Infants / young children
10 Fr	3.3 mm	Young children (2-5 years)
12 Fr	4.0 mm	Older children (5-10 years)
14 Fr	4.7 mm	Adolescents / women
16 Fr	5.3 mm	Standard adult women
18 Fr	6.0 mm	Standard adult men
20-24 Fr	6.7-8.0 mm	Haematuria / clot evacuation

Standard adult male catheterization uses a 14F to 18F Foley catheter. If a standard Foley fails (e.g., due to urethral stricture or prostatic enlargement), a coudé catheter (firmer, angled tip) may be tried.

Tintinalli's Emergency Medicine, 7th Ed., Chapter 92

Types of Foley Catheter

Type	Key Feature	Use
Standard 2-way Foley	Two lumens	Urinary drainage, retention
3-way irrigation Foley	Three lumens	Post-TURP, haematuria with clots
Coudé catheter	Angled curved tip	BPH, urethral stricture, difficult catheterization
Silicone Foley	Latex-free	Latex allergy, long-term use
Hydrogel-coated Foley	Slippery coating	Long-term indwelling (reduces infection, encrustation)
Antimicrobial-coated	Silver alloy or nitrofurazone	ICU, CAUTI prevention
Suprapubic catheter	Enters via abdominal wall	When urethral route not possible

How It Works: Step by Step

Sequential steps of Foley catheter insertion in a male patient - A through F

Step 1 - Preparation: Anesthetic lubricant (2% lidocaine jelly, 10-15 mL) injected into the urethra 5-10 minutes before insertion. In males, retract foreskin if uncircumcised.

Step 2 - Insertion: Insert the lubricated catheter horizontally into the meatus. In males, hold the penis at 90° (perpendicular to body) to straighten the penile urethra.

Step 3 - Advance: Gently advance until the catheter bifurcation (the proximal Y-junction) is at the meatus - this confirms the tip is well inside the bladder, not just at the bladder neck.

Step 4 - Confirm placement: Urine freely flows back through the drainage lumen - this confirms bladder entry.

Step 5 - Inflate balloon: Inflate the retention balloon with sterile water (NOT saline, which can crystallize in the valve):

5-10 mL for adult (10 mL balloon)
3-5 mL for paediatric
Never inflate before urine return - inflating in the urethra causes severe pain and urethral injury

Step 6 - Seat at bladder neck: Gently pull back on the catheter until slight resistance is felt - the balloon seats against the bladder neck, securing the catheter.

Step 7 - Connect drainage bag: Connect to a closed sterile drainage system (leg bag for mobile patients, bedside bag for immobile/inpatient).

Step 8 - Secure to thigh: Tape or strap catheter to inner thigh to prevent traction-related urethral injury.

Ultrasound showing Foley catheter balloon inflated within the bladder/prostatic urethra - a common misplacement site

Ultrasound showing Foley balloon inflated within the prostatic urethra - incorrect position. The balloon must always be in the bladder, not the urethra.

Clinical Indications for Foley Catheterization

Therapeutic

Acute urinary retention - the primary indication; provides immediate bladder decompression
Chronic urinary retention (neurogenic bladder, spinal cord injury)
Perioperative monitoring - accurate hourly urine output measurement in surgery/ICU
Immobile patients - prevention of skin breakdown from urinary incontinence
Bladder irrigation after prostate/bladder surgery (3-way catheter)
Bladder decompression before abdominal procedures (e.g., before paracentesis, laparotomy)
Urethral obstruction bypass (stricture, BPH, tumour)

Diagnostic

Urine specimen collection for culture (especially in women/children where clean-catch is unreliable)
Voiding cystourethrography (VCUG) - catheter fills bladder with contrast for imaging
Urodynamic studies - measuring bladder pressures
Measure post-void residual volume

Causes of Urinary Retention Requiring Catheterization

Category	Examples
Obstructive (Men)	BPH, prostate cancer, phimosis, meatal stenosis, urethral stricture
Obstructive (Women)	Cystocele, uterine/ovarian tumour, pelvic organ prolapse
Neurogenic	Spinal cord injury, MS, Parkinson's, cauda equina syndrome, diabetes
Pharmacological	Anticholinergics, opiates, alpha-agonists, antidepressants, antihistamines
Post-operative	Epidural anaesthesia, post-surgery bleeding/clots
Traumatic	Urethral/bladder injury
Paediatric-specific	Posterior urethral valves, rhabdomyosarcoma of bladder, urethral atresia

Tintinalli's Emergency Medicine, Tables 92-1 to 92-3

Post-Catheterization Care

After draining a long-standing, large-volume retention (800-1500 mL):

Monitor for postobstructive diuresis (>200 mL/hour urine output)
Monitor renal function - may develop postobstructive acute kidney injury
Monitor electrolytes - especially in prolonged retention
Antibiotics are NOT routinely given for asymptomatic bacteriuria; reserved for symptomatic UTI
Alpha-blockers (alfuzosin 10 mg/day, or tamsulosin 0.4 mg/day) can be started to relax the bladder neck and improve the chance of successful voiding when the catheter is eventually removed

Home care:

Connect to a leg bag during the day (smaller, concealed under clothes)
Swap to a larger overnight bag at night (greater capacity)
Clean meatal area daily with soap and water
Keep drainage bag below bladder level at all times (gravity drainage)

Foley Catheter in Paediatrics

Key Differences in Children

Children require special consideration for catheterization due to:

Smaller urethral calibre - much smaller bore tubes, extreme care to avoid mucosal trauma
Proportionally longer urethra relative to body size in males
Undescended testes, phimosis, hypospadias, epispadias - anatomical variants common in male children
Psychological distress - catheterization is frightening; appropriate restraint, distraction, and analgesia are essential
Different disease spectrum - congenital anomalies, posterior urethral valves, neurogenic bladder (spina bifida), trauma
Smaller balloon volumes - paediatric catheters use 3-5 mL balloons (vs 10 mL in adults)

Paediatric Catheter Sizes by Age

Age Group	Catheter Size	Balloon Volume
Premature neonate	5 Fr feeding tube (no balloon)	N/A
Neonate (0-1 month)	5-6 Fr	1.5-3 mL
Infant (1-12 months)	6-8 Fr	3 mL
Toddler (1-3 years)	8-10 Fr	3-5 mL
Child (3-8 years)	10-12 Fr	5 mL
Child (8-12 years)	12-14 Fr	5-10 mL
Adolescent	14-16 Fr (female), 14-18 Fr (male)	10 mL

In very young infants or neonates, a feeding tube (5 Fr) without a balloon is sometimes used as a urinary catheter, held in place by taping to the skin rather than a balloon.

Specific Paediatric Indications

Indication	Notes
Posterior urethral valves (PUV)	Most common obstructive uropathy in boys; catheter decompresses bladder acutely; may require valve ablation
Neurogenic bladder (spina bifida/myelomeningocele)	Long-term intermittent catheterization (clean intermittent catheterization, CIC) every 4-6 hours; parents and eventually the child perform this themselves
Urethral atresia / stenosis	Rare congenital cause; may need surgical dilation before catheterization
Rhabdomyosarcoma of bladder	Catheterization for urine output monitoring and diagnosis
Urinary tract infection (diagnosis)	Catheter urine specimen is the gold standard in infants <2 years (suprapubic aspiration also used)
VCUG (voiding cystourethrogram)	Catheter fills bladder with contrast to diagnose vesicoureteral reflux - very common in paediatric urology workup
Post-operative monitoring	Major surgery (cardiac, abdominal, urological)
Trauma / spinal cord injury	Acute retention; neurogenic bladder
Acute urinary retention	Posterior urethral valves, infection, pelvic mass

Clean Intermittent Catheterization (CIC) in Children

This is a cornerstone of paediatric urology. Instead of a permanently indwelling Foley catheter, the child (or parent) inserts a straight catheter every 4-6 hours to empty the bladder, then removes it. Benefits over indwelling catheter:

Dramatically lower infection rates (catheter-associated UTI risk nearly eliminated)
Preserves bladder capacity and compliance
Allows normal social activity, schooling, sports
Children as young as 5-6 years can be taught self-catheterization
Used lifelong in spina bifida, neurogenic bladder
Uses straight (non-retention) catheters - no balloon

Paediatric Insertion Technique - Key Differences

Female Children

Urethral meatus is small and difficult to visualise in infants
Use good lighting; spread labia gently with non-dominant hand
Insert catheter ~2-3 cm (infants) to 3-5 cm (children) to reach bladder
If tube enters vagina - withdraw, do not reuse (contaminated), use a new catheter and redirect

Male Children

Hold penis perpendicular to body to straighten penile urethra
In uncircumcised boys, gently retract foreskin only as far as it naturally moves - never force; phimosis is common in young boys
Phimosis (inability to retract foreskin) requires smaller catheter or occasionally urological assistance
Advance until urine flows; in young children the bladder neck is close to the surface so depth is short

Sedation / Analgesia

Topical lidocaine gel (2%) applied to meatus 3-5 minutes before insertion is standard
Young children and infants may need mild sedation or intranasal midazolam for the procedure
Oral sucrose (for neonates) reduces procedural pain
Parent presence/comfort reduces distress significantly

Complications of Foley Catheterization (Adult and Paediatric)

Complication	Details	Paediatric Specifics
Catheter-associated UTI (CAUTI)	Most common complication; risk increases with duration	Higher risk in children with neurogenic bladder
Balloon inflation in urethra	Severe pain, urethral injury	Critical to confirm urine flow before inflating
Urethral trauma / false passage	Forceful insertion; blood at meatus	More risk with phimosis, small meatus
Bladder spasm	Sensation of urgency around catheter	Oxybutynin 2.5 mg 2-3x/day can help
Catheter migration	Balloon migrates to proximal urethra - causes penile pain	Secure catheter well; check position
Bladder calculi	Long-term indwelling catheters - mineral encrustation	Encourage hydration; change catheters regularly
Urethral erosion/stricture	Large catheters, long-term use	Use smallest effective size
Postobstructive diuresis	After draining large volume retention	Monitor urine output after drainage
Haematuria	Trauma of insertion (usually clears)	May require irrigation catheter if clots

If gross blood and severe pain occur without urine return - deflate balloon immediately and remove. Do NOT reinsert - a false passage may have been created. Seek urological consultation.

Catheter Care and Prevention of CAUTI

Use closed drainage system at all times
Keep drainage bag below bladder level (but not on the floor)
Secure catheter to thigh - prevents traction and urethral trauma
Clean urethral meatus daily with soap and water
Change catheter every 4 weeks (latex) or 12 weeks (silicone) if long-term
Remove catheter as early as clinically possible - the longer it stays in, the higher the infection risk
Avoid routine antibiotic prophylaxis for asymptomatic bacteriuria (increases resistance)
In children on CIC - rinse catheters with sterile water; may be reused up to 1 week (per local protocol)

Summary: Adult vs. Paediatric Foley Catheter

Feature	Adult	Paediatric
Standard size	14-18 Fr	6-12 Fr (age-dependent)
Balloon volume	10-30 mL	3-5 mL
Material	Latex or silicone	Silicone preferred (less trauma)
Long-term management	Indwelling catheter	CIC (clean intermittent catheterization) preferred
Common indication	BPH, post-op, retention	Posterior urethral valves, neurogenic bladder, VCUG
Insertion depth (male)	15-25 cm	3-8 cm (age-dependent)
Insertion depth (female)	5-6 cm	2-4 cm (age-dependent)
Sedation needed	Usually not	Often yes (infants, young children)

Sources:

Tintinalli's Emergency Medicine: A Comprehensive Study Guide, Chapter 92 (Urinary Retention)
Campbell-Walsh-Wein Urology, 3-Volume Set (Catheterization Techniques)
Pfenninger & Fowler's Procedures for Primary Care, Chapter 110 (Bladder Catheterization)
Schwartz's Principles of Surgery, 11th Ed. (Paediatric Urology)
Bailey & Love's Short Practice of Surgery, 28th Ed. (Urological Emergencies)

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