7.3 Stoma Care, Tracheostomy Management & Oxygen Delivery

6.3 Stoma Care, Tracheostomy Management & Oxygen Delivery

Registered General Nurses in Irish hospitals encounter complex invasive devices and specialized supportive therapies across acute surgical, medical, and critical care units. Proficiency in stoma care, tracheostomy maintenance, and oxygen therapy is central to preserving airway patency, maintaining physiological stability, and preventing severe tissue injury. This section outlines the evidence-based principles, procedural protocols, and emergency safety interventions required for safe, competent nursing practice.

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1. Stoma Care: Anatomy, Classification & Peristomal Skin Integrity

A stoma is a surgically created opening on the abdominal wall connecting a portion of the gastrointestinal or urinary tract to the external surface. Caring for an ostomy requires understanding the anatomical origin of the stoma, the nature of its effluent, and the techniques necessary to preserve peristomal skin.

Anatomical Classification of Stomas

Clinical Importance of the Ileostomy Spout

Unlike the colonic mucosa, the effluent from an ileostomy contains active proteolytic digestive enzymes (trypsin, chymotrypsin) and bile salts. If this liquid contacts the skin, it digests the epidermis within hours, causing severe chemical excoriation, partial-thickness skin loss, and agonizing pain. For this reason, surgeons construct an ileostomy with a raised spout (everted bud) projecting 2 to 3 cm above the skin level. This spout directs corrosive liquid effluent directly into the centre of the appliance, keeping it away from the peristomal skin.

Clinical Stoma Assessment: Normal vs. Abnormal

Nurses must systematically assess the stoma at every appliance change:

• Viable / Healthy Stoma: Warm, moist, glistening, beefy red or vibrant pink (similar to the inside of the oral cheek). Mild oedema is normal in the early postoperative period (subsiding over 6 to 8 weeks). Stoma responds to light touch with gentle peristaltic contraction.
• Ischaemic / Necrotic Stoma (SURGICAL EMERGENCY):
  • Appearance: Pale, dusky, dark purple, grey, or black mucosa.
  • Pathophysiology: Inadequate arterial perfusion or strangulating venous congestion caused by excessive tension on the bowel mesentery, tight abdominal fascial closure, or thrombosis.
  • Action: Notify the operating surgical team immediately. Keep the patient nil-by-mouth (NPO). Prepare for urgent bedside sigmoidoscopy/endoscopy to assess the depth of necrosis below the fascial level or emergency surgical re-exploration.
• Other Stomal Complications:
  • Retraction: Stoma sinks below skin level into a depression, leading to persistent leakage and chemical dermatitis.
  • Prolapse: Excessive protrusion of bowel through the stoma aperture.
  • Stenosis: Narrowing of the stomal opening causing partial bowel obstruction.
  • Peristomal Pyoderma Gangrenosum: Painful, ulcerative inflammatory lesions (common in inflammatory bowel disease).

Appliance Changing & Peristomal Skin Care Protocol

1. Appliance Removal: Gently peel the hydrocolloid adhesive wafer downwards from top to bottom while supporting the surrounding skin with the opposite hand ("push the skin away from the adhesive"). Use adhesive remover spray or wipes to prevent mechanical epidermal stripping.
2. Cleansing: Cleanse the stoma and peristomal skin using routine warm tap water and soft non-linting dry wipes. Do not use standard bath soaps, moisturising lotions, bubble baths, or alcohol-based wipes; these leave an oily residue that prevents wafer adhesion, and chemical perfumes irritate sensitized skin.
3. Drying: Pat the peristomal skin completely dry. Moisture under the hydrocolloid barrier causes maceration and detachment.
4. Measuring the Stoma: Use a circular stoma measuring template guide. In the first 6 to 8 weeks post-surgery, stomas shrink significantly as oedema resolves.
5. Trimming the Wafer: Cut the opening of the hydrocolloid wafer exactly 1 to 2 mm larger than the base of the stoma:
   • If cut too large (>2 mm): Exposed peristomal skin is bathed in caustic effluent, leading to severe chemical erosion.
   • If cut too small (<1 mm): The edge of the wafer rubs, constricts, and lacerates the stoma, causing oedema, ulceration, or vascular strangulation.
6. Application: Apply stoma barrier paste or a moldable seal if the peristomal surface has uneven contours or creases. Smooth the wafer firmly around the stoma from the bottom up, applying gentle pressure with warm hands for 30 to 60 seconds (heat activates the hydrocolloid adhesive).

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2. Tracheostomy Care & Emergency Airway Management

A tracheostomy is a surgically created opening (stoma) in the anterior wall of the trachea (typically between the 2nd and 4th tracheal rings) through which an artificial tube is inserted to establish a secure airway, bypass an upper airway obstruction, facilitate mechanical ventilation, or enable clearance of tracheobronchial secretions.

Tracheostomy Tube Anatomy & Components

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|                      PARTS OF A TRACHEOSTOMY TUBE                               |
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| 1. OUTER CANNULA:    Main structural body; remains in the trachea; secured      |
|                      to the neck via the flange and neck ties.                  |
| 2. INNER CANNULA:    Removable inner sleeve; fits inside the outer cannula;     |
|                      inspected and cleaned regularly to prevent mucus plugging. |
| 3. OBTURATOR:        Rigid, bullet-tipped guide used exclusively during         |
|                      insertion to provide smooth passage; removed immediately.  |
| 4. FLANGE / WINGS:   Rest against anterior neck skin; displays tube size and    |
|                      type; anchored with velcro or cotton ties.                 |
| 5. CUFF & PILOT:     Low-pressure, high-volume inflatable balloon; seals the    |
|                      trachea for positive-pressure ventilation; pilot balloon   |
|                      contains one-way valve to assess cuff inflation.           |
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• Cuff Pressure Monitoring: The cuff pressure must be maintained between 20 and 30 cmH2O (15 to 22 mmHg) using a calibrated handheld manometer. Excessive pressure (>30 cmH2O) exceeds capillary perfusion pressure of the tracheal mucosa, causing ischaemia, mucosal ulceration, and tracheal stenosis. Inadequate pressure (<20 cmH2O) permits microaspiration of pharyngeal secretions and air leakage during positive-pressure ventilation.

The Mandatory Irish Bedside Emergency Equipment Bundle

In Irish acute hospitals, every patient with a tracheostomy must have an emergency safety tray kept permanently at their bedside. During handover, the receiving nurse must immediately inspect and verify the presence of all components:

1. Exact Spare Tracheostomy Tube: Same size, make, and type (cuffed or uncuffed) as the tube currently in situ.
2. One Size Smaller Spare Tube: E.g., if the patient has a Size 8.0 tube, a Size 7.0 tube must be present (vital if the stoma partially collapses or tissues swell following accidental decannulation).
3. Tracheal Dilator (Laborde 3-Bladed Forceps): Used to hold the tracheal stoma open during emergency re-cannulation.
4. Dedicated Obturator / Introducer: Specific to the patient's current tube.
5. Suction Apparatus & Catheters: Dedicated functional suction unit with appropriate sized suction catheters and rigid Yankauer suction handles.
6. Water-Soluble Lubricating Gel: Facilitates rapid re-cannulation.
7. Manual Resuscitation Bag (Ambu-Bag) & Mask: Equipped with both a 15 mm tracheostomy connector and an anatomical face mask.
8. Sterile 0.9% Saline Pods: For flushing suction tubing.
9. Bandage Scissors and Spare Cotton / Velcro Ties.

Inner Cannula Management & Hygiene

Mucus encrustation within the tube lumen is a leading cause of fatal airway obstruction. The inner cannula must be checked and cleaned or changed every 4 to 8 hours (or more frequently if secretions are thick or tenacious).

• Disposable Inner Cannulae: Discard and replace with a fresh sterile inner cannula of the identical size.
• Non-Disposable Inner Cannulae: Clean under running sterile water or sterile 0.9% saline using a dedicated soft tracheostomy cleaning brush. Inspect against light to verify complete patency, dry thoroughly with non-linting gauze, and re-lock into position.

Tracheobronchial Suctioning Protocol

Suctioning is an invasive procedure indicated only when clinical assessment reveals secretions (e.g., audible rattling, coarse crackles on auscultation, visible secretions, increased work of breathing, desaturation). Routine, scheduled suctioning without clinical indication is contraindicated.

• Catheter Sizing Rule: The outer diameter of the suction catheter must be less than half the internal diameter (ID) of the tracheostomy tube: $\text{Catheter Size (Fr)} \le 2 \times (\text{Tracheostomy Tube ID in mm} - 2)$ (Example: For an 8.0 mm ID tube, maximum catheter size is 12 Fr). An oversized catheter occludes the lumen, creating massive negative intrathoracic pressure that causes atelectasis and alveolar collapse.
• Vacuum Pressure: Set wall suction between 80 and 120 mmHg (10 to 15 kPa) in adults. High pressures induce mucosal stripping and haemorrhage.
• Procedure:
  1. Hyper-oxygenate the patient with 100% O2 for 30 to 60 seconds if clinically indicated.
  2. Using surgical ANTT and sterile gloves, insert the catheter smoothly without applying suction until the patient coughs or slight resistance is felt (then withdraw 1 cm).
  3. Apply continuous or intermittent suction while withdrawing the catheter in a gentle rotating motion.
  4. Limit suction duration to less than 10 to 15 seconds. Prolonged suctioning causes profound arterial hypoxaemia and vagal nerve stimulation, precipitating bradycardia, heart block, or cardiac arrest.

Emergency Management: Blocked Tube & Accidental Decannulation

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|                TRACHEOSTOMY EMERGENCY DECISION ALGORITHM                        |
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|  PATIENT IN ACUTE RESPIRATORY DISTRESS / STRIDOR / CYANOSIS                     |
|                                    │                                            |
|         ┌──────────────────────────┴──────────────────────────┐                 |
|         ▼                                                     ▼                 |
|  [SUSPECTED TUBE OBSTRUCTION]                          [ACCIDENTAL DECANNULATION]|
|  1. Call Emergency Team (2222).                        1. Call Emergency (2222).|
|  2. Remove Inner Cannula immediately!                  2. Extend patient's neck.|
|     (Often removes the mucus plug).                    3. Insert Laborde tracheal|
|  3. If still blocked, attempt gentle                      dilators; spread open |
|     suctioning.                                           stoma laterally.      |
|  4. If catheter does not pass, DEFLATE                 4. Lubricate spare tube  |
|     cuff and prepare for immediate                        (same size, or one size|
|     tube exchange.                                        smaller).             |
|  5. Administer 100% O2 over stoma                      5. Insert with obturator;|
|     and upper airway.                                     REMOVE OBTURATOR      |
|                                                           IMMEDIATELY.          |
|                                                        6. Confirm air exchange; |
|                                                           secure ties.          |
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[!CAUTION] The Critical Obturator Rule: When inserting a tracheostomy tube with an obturator, you must remove the obturator immediately once the tube enters the trachea. The obturator is a solid rod; leaving it in place completely occludes the patient's airway.

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3. Oxygen Delivery Systems & Clinical Humidification

Oxygen is a prescribed medication. The British Thoracic Society (BTS) and HSE guidelines mandate that oxygen must be prescribed with a specific target saturation range: 94%–98% for most acute patients, or 88%–92% for patients at risk of hypercapnic respiratory failure.

Classification of Oxygen Systems

Oxygen delivery devices are divided into Low-Flow (Variable Performance) and High-Flow (Fixed Performance) systems based on whether the device can meet the patient's total peak inspiratory demand.

Low-Flow (Variable Performance) Devices

In low-flow systems, the delivered gas flow is lower than the patient's peak inspiratory flow rate (which typically ranges from 30 to 60 L/min during distress). The patient entrains room air around the device, meaning the actual fraction of inspired oxygen ($FiO_2$) varies with their respiratory rate, tidal volume, and mouth-breathing.

• Nasal Cannulae (1 to 4 L/min): Delivers an estimated $FiO_2$ of 24% to 36% (roughly 4% increase per 1 L/min above room air 21%). Well tolerated, allows talking and eating. Flows exceeding 4 L/min cause mucosal drying, nasal crusting, and epistaxis.
• Simple Face Mask (5 to 10 L/min): Delivers an estimated $FiO_2$ of 35% to 50%.
  • MANDATORY FLOW RULE: The flow rate must never be set below 5 L/min. Flows <5 L/min allow exhaled carbon dioxide to accumulate within the mask cavity, leading to CO2 rebreathing and hypercapnia.
• Non-Rebreather Reservoir Mask (NRM) (12 to 15 L/min): Delivers an estimated $FiO_2$ of 60% to 85%+.
  • Designed with two one-way flutter valves and a reservoir bag. The reservoir bag must be fully inflated before placing the mask on the patient. Used in acute emergencies (hypoxaemic shock, trauma, cardiac arrest, sepsis).

High-Flow (Fixed Performance) Controlled Devices

High-flow systems generate total gas flows that equal or exceed the patient's maximum peak inspiratory demand, guaranteeing a precise, fixed $FiO_2$ regardless of respiratory pattern.

The Venturi Mask: Precision for Hypercapnic Risk

The Venturi mask utilizes the Bernoulli principle: high-velocity oxygen passing through a narrow orifice creates a localized drop in pressure that entrains a precise volume of ambient room air. Colour-coded entrainment valves deliver exact, reproducible oxygen concentrations:

[!IMPORTANT] COPD & Hypercapnic Respiratory Failure: In patients with Chronic Obstructive Pulmonary Disease (COPD) or severe kyphoscoliosis who chronically retain carbon dioxide, excessive uncontrolled oxygen delivery blunts hypoxic ventilatory drive, worsens ventilation-perfusion ($V/Q$) mismatch, and induces carbon dioxide retention via the Haldane effect. Always administer oxygen via a 28% (white) or 24% (blue) Venturi mask, titrating strictly to a target $SpO_2$ of 88% to 92%.

High-Flow Nasal Oxygen (HFNO / Optiflow)

Delivers heated (37°C), fully humidified gas mixtures through wide-bore soft nasal prongs at flow rates up to 60 L/min and $FiO_2$ from 21% to 100%:

• Mechanisms: Washes out anatomical dead-space in the nasopharynx (clearing CO2), matches peak inspiratory flow, generates a low level of positive end-expiratory pressure (PEEP ~2 to 5 cmH2O), and preserves mucociliary clearance.

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4. Clinical Pitfalls & OSCE Station Traps