7.2 Urinary Catheterisation: Aseptic Insertion & CAUTI Prevention

6.2 Urinary Catheterisation: Aseptic Insertion & CAUTI Prevention

Urinary catheterisation is one of the most frequently performed invasive clinical procedures in acute hospitals. However, the presence of an indwelling urinary catheter carries significant clinical risks, most notably Catheter-Associated Urinary Tract Infection (CAUTI), urethral trauma, and secondary urosepsis. Under the Health Service Executive (HSE) National Antimicrobial Resistance and Infection Control (AMRIC) guidelines, Registered General Nurses must practice rigorous clinical stewardship: avoiding inappropriate catheter insertion, utilizing flawless surgical aseptic technique during placement, and vigorously adhering to maintenance bundles to remove catheters at the earliest possible opportunity.

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1. Epidemiology & Pathogenesis of CAUTI (HSE AMRIC Guidelines)

CAUTI accounts for up to 30% to 40% of all healthcare-associated infections (HCAIs) in acute hospital systems. In Ireland, point prevalence surveys consistently show that approximately one in five acute inpatients has an indwelling urinary catheter in situ at any given time.

Pathogenesis: The Biofilm Barrier

Within 24 to 48 hours of catheter insertion, microorganisms colonize both the external and internal surfaces of the catheter tubing, forming a complex, resilient biofilm. This extracellular polysaccharide matrix protects embedded bacteria (commonly Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Enterococcus faecalis, and Pseudomonas aeruginosa) from host immune defenses and systemic antimicrobial agents.

• Extraluminal Route (Early / Direct): Microorganisms ascend along the thin mucous fluid film between the external catheter surface and the urethral mucosa. This occurs primarily during insertion due to inadequate hand hygiene, contaminated equipment, or inadequate perineal cleansing, or subsequently via perineal flora.
• Intraluminal Route (Late / Ascending): Microorganisms gain access to the interior lumen of the catheter following a breach in the closed drainage system (e.g., disconnecting the catheter-bag junction or contaminating the drainage spigot during emptying) and ascend into the bladder within 24 to 48 hours.
• The Cumulative Risk: The risk of bacteriuria increases by 3% to 7% for each day an indwelling catheter remains in situ. By Day 30, virtually 100% of catheterised patients develop bacteriuria.

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2. Clinical Indications: The H-A-N-D-L-E Criteria vs. Inappropriate Use

Under HSE AMRIC national infection prevention policy, an indwelling urinary catheter must only be inserted when there is an explicit, documented medical or surgical indication.

Valid Indications: The H-A-N-D-L-E Mnemonic

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|                       THE H-A-N-D-L-E INDICATIONS CRITERIA                      |
+---------------------------------------------------------------------------------+
| H - HEMODYNAMIC:     Accurate, hourly urine output monitoring in critically    |
|                      ill, unstable patients (e.g., septic shock, ICU).          |
| A - ACUTE RETENTION: Relieving acute urinary retention or mechanical bladder    |
|                      outlet obstruction (confirmed by bladder scanner).         |
| N - NEUROGENIC:      Managing neurogenic bladder dysfunction or spinal cord     |
|                      injury with persistent urinary retention.                  |
| D - DURING SURGERY:  Specific operative procedures (pelvic, colorectal, urology|
|                      or prolonged surgery requiring fluid resuscitation).       |
| L - LARGE WOUNDS:    Promoting healing of severe open Stage 3 or 4 sacral or    |
|                      perineal pressure injuries in incontinent patients.        |
| E - END-OF-LIFE:     Enhancing comfort and dignity in palliative/end-of-life    |
|                      care when movement causes severe pain or distress.         |
+---------------------------------------------------------------------------------+

Inappropriate Indications for Catheterisation

Inserting an indwelling catheter for any of the following reasons violates HSE AMRIC standards:

1. Nursing Convenience / Staff Shortages: Using a catheter as a substitute for routine nursing continence care or to minimize bed-linen changes.
2. Routine Incontinence Management: Managing urinary incontinence in an alert or semi-mobile patient who does not have severe open sacral/perineal pressure ulceration.
3. Routine Urine Sample Collection: Obtaining a urine specimen when a non-invasive clean-catch, mid-stream urine (MSU), or urinal collection is feasible.
4. Uncomplicated Postoperative Recovery: Prolonged catheterisation beyond 24 to 48 hours following surgery without documented retention or hemodynamic instability.
5. Patient or Family Request: Initiating invasive catheterisation solely at family request without an underlying medical necessity.

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3. Catheter Selection, Sizing & Retention Balloon Safety

Selecting the correct catheter material, diameter, and balloon specification prevents urethral ischaemia, tissue necrosis, and mechanical trauma.

Sizing: The French Gauge (Fr / Charrière)

The external circumference of a catheter is measured in French units ($1\text{ Fr} = \frac{1}{3}\text{ mm}$ outer diameter).

• Adult Females: 12 to 14 Fr. The female urethra is short (~4 cm) and straight. A 12–14 Fr catheter provides adequate luminal drainage while minimizing mechanical irritation to the urethral mucosa.
• Adult Males: 14 to 16 Fr. The male urethra is longer (~18–20 cm) with natural anatomical curvatures. A 14–16 Fr catheter provides sufficient structural stiffness to navigate the bulbous and prostatic urethra without bending or kinking.
• Larger Gauges (18 to 22 Fr): Reserved for acute macroscopic haematuria with clot retention, requiring a 3-way continuous bladder irrigation (CBI) system.

[!WARNING] The Danger of Oversizing: Always select the smallest gauge catheter that ensures adequate urinary drainage. Oversized catheters compress the peri-urethral glands, causing mucosal ischaemia, stricture formation, and severe spasms.

Catheter Materials: Short-Term vs. Long-Term

• PTFE (Teflon) Coated Latex: Suitable for short-term use (up to 14–28 days). Smooth surface eases insertion, but strictly contraindicated in known latex allergy.
• Hydrogel-Coated Latex: Absorbs fluid to form a slippery cushion, reducing friction. Suitable for up to 12 weeks.
• 100% All-Silicone: Inert, non-allergenic, large internal lumen relative to outer gauge. First choice for patients with latex hypersensitivity or long-term catheterisation (up to 12 weeks).

Balloon Inflation Fluid & Mechanics

• Standard Adult Balloon Volume: 10 mL. The retention balloon is designed to hold the catheter tip securely at the bladder neck.
• Fluid Type: Sterile Water Only. Always inflate with exactly 10 mL of sterile water.
• Why Normal Saline is BANNED: Saline crystallises inside the balloon and within the microscopic inflation channel over time. When attempting removal, the crystals occlude the channel, preventing deflation and requiring emergency urological puncture.
• Why Air is BANNED: Air causes the balloon to float inside the bladder, tilting the tip against the sensitive trigone, inducing severe bladder spasms, and increasing the risk of premature expulsion.

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4. Step-by-Step Surgical ANTT Insertion Protocol

Urinary catheterisation is a sterile invasive procedure requiring Surgical Aseptic Non-Touch Technique (Surgical ANTT): sterile gloves, a critical micro-sterile field, sterile drapes, and untouched sterile components.

Pre-Procedure Preparation

1. Confirm identity using two patient identifiers against the wristband.
2. Assess mental capacity, explain the clinical rationale, outline risks (discomfort, infection), and obtain informed consent.
3. Offer and arrange a chaperone (mandatory for intimate examinations in Irish healthcare).
4. Perform hand hygiene, clean the clinical dressing trolley with detergent wipes, and assemble equipment: sterile catheter pack, catheter of appropriate gauge, 10 mL sterile water prefilled syringe, sterile lignocaine 2% gel, sterile collection bag, and catheter strap/stand.

Patient Positioning

• Female: Position in the dorsal recumbent position with knees flexed, feet flat on the mattress, and hips gently abducted ("frog-leg" position). Support privacy with a disposable modesty sheet.
• Male: Position in the supine position with legs flat and slightly apart. Drape thighs leaving the external genitalia exposed.

Peri-Urethral Cleansing

1. Wash hands and don clean disposable gloves. Inspect the perineum and external genitalia; if visible organic matter is present, cleanse with warm water and mild soap.
2. Remove gloves, perform alcohol rub hand hygiene, open the sterile catheterisation pack on the trolley, and don sterile gloves.
3. Position the sterile fenestrated drape over the genitalia to establish a sterile field.
4. Female Cleansing: Using the non-dominant hand, carefully part the labia minora. This hand is now contaminated and must remain in position until insertion is complete. Using sterile swabs saturated with sterile 0.9% sodium chloride, clean the urethral meatus using single, firm downward strokes from anterior to posterior (clitoris toward anus). Use a fresh swab for each stroke.
5. Male Cleansing: Hold the shaft of the penis at a 90° angle using the non-dominant hand (now contaminated). If uncircumcised, gently retract the foreskin (prepuce). Cleanse the glans penis in a circular motion starting at the urethral meatus and moving outwards toward the coronal sulcus using sterile 0.9% saline swabs. Use a fresh swab for each wipe.

Anaesthetic & Lubricating Gel Instillation

Instillation of sterile 2% lignocaine gel (e.g., Instillagel) is mandatory in modern practice:

• Dosage: 6 mL for females; 11 mL for males.
• Efficacy Interval: Wait a full 3 to 5 minutes after instillation. In males, gently compress the urethral meatus to keep the gel in the penile urethra. This 3–5 minute dwell time allows the lignocaine to achieve complete mucosal anaesthesia and relaxes the muscular external urethral sphincter, drastically reducing insertion resistance and pain.

Catheter Insertion & Balloon Inflation

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|                CATHETER ADVANCEMENT & BALLOON SAFETY BENCHMARKS                 |
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| FEMALE:  Advance 5-7 cm until urine drains  --->  ADVANCE FURTHER 2 TO 3 CM      |
|                                                   before balloon inflation.     |
|                                                                                 |
| MALE:    Advance 15-20 cm until urine drains ---> ADVANCE FULLY TO BIFURCATION  |
|                                                   before balloon inflation.     |
+---------------------------------------------------------------------------------+

1. Female Insertion: Gently insert the catheter tip into the urethral orifice. Advance smoothly 5 to 7 cm until urine begins to drain into the sterile receiver. Do not inflate the balloon immediately. Advance the catheter an additional 2 to 3 cm to ensure the retention balloon has fully crossed the internal urethral orifice and resides entirely within the bladder lumen.
   • OSCE Landmark Tip: If the catheter is inadvertently inserted into the vagina, leave it in place as an anatomical marker, perform hand hygiene, don fresh sterile gloves, and insert a new sterile catheter into the urethral orifice above.
2. Male Insertion: Maintain gentle upward traction on the penile shaft at an angle of 60° to 90° to straighten the S-shaped anterior urethral curvature. Advance the catheter smoothly 15 to 20 cm. When urine begins to flow, continue advancing the catheter all the way to its bifurcation (Y-junction).
3. Balloon Inflation: Slowly inject 10 mL of sterile water from the prefilled syringe. Observe the patient's face closely.
   • Pain Warning: If the patient complains of sharp pain, or if resistance is encountered against the syringe plunger, STOP IMMEDIATELY. Do not force the water in. This indicates the balloon is sitting inside the prostatic or membranous urethra! Deflate the balloon completely, advance the catheter further, and re-attempt gentle inflation.
4. Positioning & Prepuce Reduction: Once inflated, gently withdraw the catheter until slight mechanical resistance is felt as the balloon seats at the bladder neck.
   • CRITICAL MALE STEP: If the foreskin was retracted, immediately pull the foreskin forward over the glans penis. Failure to reduce the prepuce results in venous constriction, severe oedema, and paraphimosis, which can lead to ischemic glans necrosis.
5. Securing & Drainage System: Connect the catheter to a sterile closed drainage bag. Anchor the catheter tubing to the anterior upper thigh (in females) or lower abdomen/upper thigh (in males) using a dedicated stabilization strap (e.g., StatLock) to prevent mechanical traction on the bladder neck.

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5. Maintenance Bundle & CAUTI Prevention Strategy

Once the catheter is in place, the registered nurse must maintain a strict infection prevention bundle to prevent bacterial ingress.

The HSE AMRIC CAUTI Prevention Bundle

The Golden Question: "Get the Catheter Out!"

The single most effective measure for preventing CAUTI is the daily review of catheter necessity. Every day during handover and multidisciplinary ward rounds, the nurse must ask: $\text{Does this patient still meet H-A-N-D-L-E criteria?}$ If the indication is no longer present, the catheter must be removed immediately without delay, followed by a post-removal voiding trial (Trial Without Catheter / TWOC) monitored via bladder scanning.

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6. Clinical Pitfalls & OSCE Station Traps