6.3 Urinary Catheterisation & Invasive Device Care

6.3 Urinary Catheterisation & Invasive Device Care

Invasive clinical devices such as urethral catheters and peripheral intravenous cannulas (PIVCs) are essential tools in modern patient care. However, they breach the body's natural anatomical defense barriers, presenting significant risks of healthcare-associated infections, including Catheter-Associated Urinary Tract Infections (CAUTI) and catheter-related bloodstream infections (CRBSIs). Registered nurses must apply meticulous aseptic technique, evidence-based insertion protocols, structured device scoring, and prompt removal strategies.

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Indications for Urinary Catheterisation & The HOUDINI Protocol

Urinary catheterisation must never be performed for nursing convenience or as a routine response to incontinence. It carries a substantial risk of infection and urethral trauma. The HOUDINI protocol is a validated nurse-led evidence framework used across UK trusts to evaluate whether catheter insertion or continuation is clinically justified.

Valid Indications (The HOUDINI Framework)

• H - Hematuria: Gross hematuria with urinary tract blood clots requiring continuous bladder irrigation.
• O - Obstruction: Acute urinary retention or mechanical bladder outlet obstruction.
• U - Urological Surgery: Recent urological, gynecological, or pelvic reconstructive surgery.
• D - Decubitus Ulcer: Stage 3 or 4 sacral/perineal pressure ulcers in an incontinent patient where healing is compromised by urine contamination.
• I - Input / Output: Precise hourly fluid balance monitoring required in critically ill or hemodynamically unstable patients.
• N - Nursing End-of-Life Care: Palliative or end-of-life comfort measures to prevent painful repositioning.
• I - Immobilisation: Strict physical immobilisation required due to unstable spinal or pelvic fractures.

Prior to insertion, the nurse must obtain informed consent, ensure a chaperone is offered, and select the smallest appropriate French (Ch) gauge catheter (typically 12–14 Ch for females, 14–16 Ch for males) to minimize urethral trauma.

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Anatomical & Procedural Aspects of Urethral Catheterisation

Urethral catheterisation is performed using Surgical ANTT, requiring sterile gloves, sterile drapes, and a sterile field.

Crucial Safety Precautions

• Never inflate the balloon until urine flow is observed and the catheter has been advanced to the appropriate depth. In males, inflating the balloon within the prostatic urethra causes severe urethral rupture and hemorrhage.
• Inflation fluid: Use only sterile water supplied in pre-filled syringes. 0.9% sodium chloride must never be used to inflate catheter balloons because salt crystallises over time, blocking the inflation channel and preventing balloon deflation during removal.
• Paraphimosis Prevention: In uncircumcised males, the foreskin must be retracted for cleansing, but must be fully replaced forward over the glans immediately after catheter insertion to prevent paraphimosis (vascular compromise of the glans penis).

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CAUTI Prevention & Closed System Maintenance

Up to 80% of healthcare-associated urinary tract infections are attributable to indwelling catheters. Implementation of the CAUTI Prevention Bundle is mandatory:

                      ┌─────────────────────────────────┐
                      │     CAUTI Prevention Bundle     │
                      └────────────────┬────────────────┘
                                       │
          ┌────────────────────┼────────────────────┐
          ▼                    ▼                    ▼
  ┌───────────────┐    ┌───────────────┐    ┌───────────────┐
  │ Unbroken      │    │ Gravity &     │    │ Hygiene &     │
  │ Closed System │    │ Positioning   │    │ Securing      │
  │ (Never break  │    │ (Below bladder│    │ (Daily soap & │
  │ connection)   │    │ off floor)    │    │ thigh strap)  │
  └───────┬───────┘    └───────┬───────┘    └───────┬───────┘
          │                    │                    │
          └────────────────────┼────────────────────┘
                               │
                               ▼
                      ┌─────────────────────────────────┐
                      │ Daily TWOC & Prompt Removal     │
                      └─────────────────────────────────┘

Core CAUTI Maintenance Standards

1. Maintain an Unbroken Closed Drainage System: The connection between the catheter and drainage tubing must never be disconnected unless clinically essential. Empty the bag via the tap using a clean single-use container.
2. Drainage Bag Positioning: Maintain continuous gravity drainage by hanging the bag below the level of the bladder at all times. Never place the drainage bag on the floor.
3. Catheter Securing: Secure the catheter tubing to the patient's thigh (or lower abdomen in males) using a dedicated securing device (e.g., StatLock) to prevent traction and urethral trauma.
4. Meatal Hygiene: Wash the meatus daily with mild soap and warm water. Routine application of antiseptic creams or powders to the meatus is unnecessary and harmful.
5. Daily Removal Review: Re-evaluate catheter necessity daily; perform a Trial Without Catheter (TWOC) at the earliest clinical opportunity.

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Peripheral Intravenous Cannula (PIVC) Insertion & Maintenance

Peripheral cannulas are the most common invasive vascular devices. Inappropriate management leads to phlebitis, extravasation, and cannula sepsis.

Insertion Protocol (Standard ANTT)

• Site Selection: Select a straight vein in the non-dominant forearm or hand (e.g., cephalic or basilic vein). Avoid flexure points (antecubital fossa), damaged skin, or limbs affected by stroke or lymphoedema.
• Skin Antisepsis: Clean the insertion site with an applicator containing 2% chlorhexidine gluconate in 70% isopropyl alcohol. Scrub with friction for 30 seconds and allow to air dry completely for 30 seconds.
• Dressing & Labeling: Secure with a sterile, transparent semi-permeable dressing. Document insertion date, time, cannula gauge, and operator initials directly on the dressing margin.

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Visual Infusion Phlebitis (VIP) Score & Flushing Protocols

To detect early mechanical or chemical vein irritation, nurses must inspect PIVC insertion sites at least once per shift (every 8 hours) using the Visual Infusion Phlebitis (VIP) Score.

Cannula Flushing Protocols

• Flush Fluid: Use 0.9% Sodium Chloride (Sterile Normal Saline).
• Syringe Size: Always use a minimum 10 mL syringe size. Smaller syringes generate excessively high injection pressures capable of rupturing small peripheral veins or catheter lumens.
• Flushing Technique: Employ a push-pause (pulsatile) technique (administering short 1 mL bursts) to create turbulent flow inside the cannula, effectively clearing blood components and medication residues.
• Timing: Flush before and after medication administration, and at least every 24 hours when the cannula is not in active use. Maintain positive pressure while clamping to prevent backflow of blood into the tip.