11.4 Aseptic Non-Touch Technique (ANTT), Bladder Catheterisation & Cannulation

Aseptic Non-Touch Technique (ANTT), Bladder Catheterisation & Cannulation

Invasive clinical procedures represent vital components of intermediate and high-dependency midwifery practice. Interventions such as peripheral intravenous cannulation and female urinary catheterisation are essential for fluid resuscitation, parenteral drug administration, anaesthetic management, and intrapartum monitoring. However, every invasive procedure breaches the body's natural anatomical barriers, introducing substantial risks of Healthcare-Associated Infections (HCAIs), maternal sepsis, thrombophlebitis, and urethral trauma. To ensure maternal safety and clinical excellence, midwives must apply the rigorous principles of the Aseptic Non-Touch Technique (ANTT) framework across all clinical settings.

---

The Aseptic Non-Touch Technique (ANTT) Framework

The Aseptic Non-Touch Technique (ANTT) is the internationally recognized, standardized clinical practice framework designed to protect patients from healthcare-acquired contamination during invasive procedures and wound care. Developed to address variability in clinical practice, ANTT is based upon a simple, universal principle: maintaining asepsis by protecting Key-Parts and Key-Sites from direct or indirect microorganism transfer.

The Core Anatomy of ANTT: Key-Parts & Key-Sites

• Key-Parts: The critical, sterile components of medical equipment that will enter the patient's vascular system, internal organs, or sterile body cavities, or come into direct contact with other sterile equipment or liquid infusions.
  • Examples: The metal needle and plastic shaft of an IV cannula, the tip of an IV administration set luer lock, the tip and drainage shaft of a urinary catheter, the needle and plunger tip of a syringe, and the internal surface of a sterile medication vial.
• Key-Sites: Open surgical wounds, insertion entry sites, or mucous membrane orifices that provide a direct pathway for pathogens into sterile body compartments.
  • Examples: The intravenous cannula puncture site on the maternal vein, the female urethral meatus, an episiotomy or caesarean section incision, and an umbilical cord stump.

Standard ANTT vs. Surgical ANTT

The ANTT framework stratifies all invasive procedures into two distinct methodological approaches based on procedural duration, technical complexity, and the number/size of Key-Parts:

Hand Hygiene: The Foundation of Asepsis

Adherence to the World Health Organization (WHO) 5 Moments for Hand Hygiene is non-negotiable:

1. Before touching a patient.
2. Before a clean or aseptic procedure.
3. After body fluid exposure risk.
4. After touching a patient.
5. After touching patient surroundings.

Midwives must decontaminate hands using an alcohol-based hand rub (ABHR) for at least 20 to 30 seconds when hands are visibly clean. When hands are visibly soiled, contaminated with bodily fluids, or when caring for women with spore-forming infections (such as Clostridioides difficile), hands must be washed thoroughly with antiseptic soap and warm running water for 40 to 60 seconds, as alcohol rubs do not eradicate bacterial spores.

---

Peripheral Intravenous Cannulation (PIVC) in Maternity

Peripheral intravenous cannulation is indicated in maternity care for administering intravenous hydration, continuous oxytocin infusions (induction or augmentation), intravenous antibiotics, regional analgesia fluid preloading, and urgent blood product administration during obstetric emergencies.

Cannula Gauge Selection & Flow Dynamics

Cannulae are colour-coded internationally according to external needle gauge diameter. In obstetrics, cannula selection must anticipate potential intrapartum decompensation, particularly Postpartum Haemorrhage (PPH).

Step-by-Step PIVC Insertion Technique

1. Vein Selection: Select a prominent, straight, non-tortuous vein on the dorsal aspect of the hand or forearm (cephalic or basilic veins). Avoid areas of joint flexion (antecubital fossa or wrist) whenever possible to prevent cannula kinking and mechanical phlebitis. Avoid limbs with arteriovenous fistulas or active skin infections.
2. Skin Antisepsis: Disinfect the proposed insertion site using an applicator containing 2% chlorhexidine gluconate in 70% isopropyl alcohol (e.g., ChloraPrep). Apply a vigorous cross-hatch friction scrub for at least 30 seconds. Allow the area to air dry completely for at least 30 seconds.
   • Never fan, blow on, or dab the skin to accelerate drying.
   • Strict prohibition: NEVER re-palpate the vein after skin antisepsis has been performed, even with gloved hands, as this re-contaminates the Key-Site.
3. Insertion: Apply distal skin traction to stabilize the vein. Introduce the cannula bevel-up at an angle of 10 to 30 degrees to the skin. Advance smoothly until the primary flashback of blood is visualized in the flashback chamber.
4. Advancement: Lower the angle of the cannula flush with the skin. Advance the plastic catheter over the metal needle stylet into the vein lumen while retracting the needle stylet slightly. Release the venous tourniquet.
5. Securing and Flushing: Occlude the vein proximal to the cannula tip with digital pressure. Withdraw the sharp stylet and discard it immediately into a point-of-use sharps container. Attach a needle-free connector or extension set. Secure the cannula using a sterile, transparent semi-permeable polyurethane dressing, ensuring the insertion Key-Site remains clearly visible for inspection.
6. Patency Assessment: Flush the cannula with 5 to 10 mL of sterile 0.9% sodium chloride, checking for smooth flow, absence of resistance, and absence of local swelling or maternal discomfort.

Visual Infusion Phlebitis (VIP) Score Monitoring

Every indwelling peripheral cannula must be formally evaluated at least every 8 to 12 hours (and before every infusion/injection) using the Visual Infusion Phlebitis (VIP) Score:

VIP 0: IV site appears healthy, no signs of phlebitis ──────────> Continue routine monitoring
VIP 1: Slight pain near IV site OR slight erythema ────────────> Early sign: observe closely
VIP 2: Pain at site WITH erythema OR swelling ─────────────────> Early phlebitis: RESITE CANNULA
VIP 3: Pain, erythema, swelling, induration / cord ────────────> Medium stage: RESITE & TREAT
VIP 4: Advanced cord, severe pain, extensive erythema ─────────> Severe: RESITE & INITIATE TREATMENT
VIP 5: Overt pyrexia, purulent discharge, severe thrombophlebitis > Remove, blood cultures, urgent MDT

---

Female Bladder Catheterisation in Maternity Care

Urinary catheterisation involves the insertion of a flexible drainage tube through the urethra into the urinary bladder. In maternity care, catheterisation may be intermittent (single drainage and immediate removal) or indwelling (continuous drainage via a retention balloon).

Clinical Indications in Maternity Pathways

• Regional Epidural / Spinal Analgesia: Regional neuraxial blockade causes temporary motor, sensory, and autonomic sympathetic denervation of the bladder detrusor muscle, abolishing the micturition reflex and sensation of bladder fullness. An indwelling catheter prevents acute maternal urinary retention and bladder overdistension.
• Obstructed Labour / Progress Delay: A distended maternal urinary bladder occupies the true pelvic cavity, displacing the uterus and physically impeding the descent, flexion, and internal rotation of the fetal presenting part. Relieving retention restores normal mechanics.
• Operative Birth: Decompressing the bladder prior to an instrumental delivery (forceps or ventouse) or caesarean section moves the bladder dome away from the surgical field, minimizing the risk of accidental bladder laceration or hysterotomy extension.
• Postpartum Haemorrhage (PPH) Management: A full bladder mechanically displaces the uterine fundus upwards and to the right, inhibiting endogenous myometrial contraction and triggering uterine atony. Emptying the bladder allows effective uterine contraction and enables accurate hourly urine output monitoring via a closed urometer system (target: ≥30 mL/hour or ≥0.5 mL/kg/hour).
• Severe Pre-eclampsia / Eclampsia: Facilitates precise fluid balance management to detect oliguria and prevent pulmonary oedema.

Catheter Selection: Types, Materials & Physics

1. Nelaton Catheter (Intermittent): Single-lumen, straight polyvinyl chloride or silicone tube without a retention balloon. Used for single, immediate bladder decompression (e.g., prior to instrumental delivery or to obtain an uncontaminated urine sample).
2. Foley Catheter (Indwelling): Dual-lumen tube comprising a primary central urinary drainage lumen and an independent secondary inflation channel terminating in a retention balloon.
   • Material: Short-term catheterisation (<14 days) utilizes hydrogel-coated latex or PTFE-coated latex. For women with known latex allergy or requiring intermediate catheterisation, 100% all-silicone catheters are mandatory.
   • Size: Standard female urethral catheter sizes range between 12 French (Fr) and 14 French (Fr) (external circumference in millimetres divided by π; 1 Fr = 0.33 mm). Excessive catheter sizes cause mechanical urethral necrosis and discomfort.
   • Balloon Inflation: The retention balloon is designed to retain the catheter tip securely at the bladder neck. The balloon must be inflated exclusively with 10 mL of sterile water. Never use 0.9% sodium chloride, as the salt solute can precipitate and crystallize within the narrow inflation channel, obstructing the valve and preventing balloon deflation during removal. Never inflate with air, as air bubbles float, tilting the drainage eyes away from the bladder floor and impairing drainage.

Step-by-Step Catheterisation Technique

Female catheterisation must be conducted as a Surgical ANTT procedure utilizing a critical sterile field, sterile gloves, and sterile drapes:

1. Positioning and Dignity: Place the woman in the dorsal recumbent position with knees flexed, feet flat on the bed, and hips abducted ('frog-leg' position). Ensure visual privacy with screens and warm ambient lighting. Illuminate the perineum directly.
2. Aseptic Field & Draping: Perform hand hygiene, don sterile gloves, and establish a sterile working field between the woman's thighs using fenestrated sterile drapes.
3. Urethral Cleansing: Part the labia majora and minora with the non-dominant hand. Once this hand touches the maternal mucosa, it is deemed contaminated and must not leave the labia until insertion is completed. Cleanse the urethral meatus using sterile gauze soaked in sterile 0.9% sodium chloride or approved water-based antiseptic swabs. Wipe in a single, smooth stroke from anterior to posterior (clitoris towards the anus), using a fresh swab for each stroke.
4. Local Anaesthesia & Lubrication: Instil 6 to 10 mL of sterile 2% lidocaine lubricating gel (e.g., Instillagel) directly into the urethral meatus using the pre-filled sterile syringe nozzle. Wait 3 to 5 minutes to ensure adequate mucosal anaesthesia and urethral dilatation, substantially reducing maternal pain and tissue resistance.
5. Insertion: Gently introduce the sterile catheter tip into the urethral meatus, directing it upwards and backwards following the anatomical curve of the female urethra (approximately 3 to 5 cm in length). Advance smoothly until urine flows freely into the drainage bag.
6. The Critical 2.5–5 cm Advancement Rule: Once urine appears, advance the catheter an additional 2.5 to 5 cm (1 to 2 inches) further into the bladder cavity before inflating the balloon.
   • Rationale: Because the retention balloon sits 1 to 2 cm behind the drainage eyelets, the initial appearance of urine occurs when only the catheter tip has crossed the bladder neck. Inflating the balloon immediately at the first sign of urine risks inflating the balloon directly inside the sensitive, narrow female urethra, causing excruciating pain, extensive urethral rupture, and severe haemorrhage.
7. Balloon Inflation and Positioning: Slowly inject exactly 10 mL of sterile water into the balloon inflation port. If the woman reports acute pain during inflation, stop immediately, aspirate the fluid, advance the catheter further, and re-attempt. After successful inflation, gently withdraw the catheter until slight resistance is encountered, confirming that the balloon rests snugly against the bladder neck.

CAUTI Prevention Bundles in Maternity

Catheter-Associated Urinary Tract Infections (CAUTIs) represent a major source of preventable maternal morbidity. Midwives must enforce strict preventative care:

• Closed Drainage System: Never disconnect the drainage bag from the catheter tubing unless clinically unavoidable. Disconnection breaches the sterile closed system, allowing ascending bacterial entry.
• Dependent Drainage: Ensure the drainage bag is maintained continuously below the level of the bladder on a dedicated bed stand, never resting directly on the floor. Avoid looping or kinking of the drainage tubing to prevent urinary stasis.
• Meatal Hygiene: Cleanse the urethral meatus daily with warm water and mild soap during routine hygiene.
• Prompt Removal: Regularly review the clinical indication. Catheters should be removed as soon as the woman is mobile, regional anaesthesia has fully receded, or PPH monitoring has concluded, ensuring normal voiding is re-established within 4 to 6 hours post-removal.