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PE23.9-11 | Gastrointestinal Procedures — SDL Guide (Part 2)
Interpretation of Findings and Complications
Correct procedure technique is only half the skill; the other half is the ability to recognise that a procedure has succeeded, failed, or produced a complication — and to respond promptly. Each of the three procedures has a distinct complication profile that you must know before performing them.
NG tube — complications and recognition:
The most serious complication of NG tube insertion is pulmonary misplacement — the tube enters the trachea and bronchi. Clinical signs include coughing, gagging, cyanosis, and respiratory distress during insertion; if unrecognised and feeding is started, aspiration pneumonia or pneumothorax can result. The verification protocol (pH ≤5 on aspiration) is specifically designed to exclude this. Never use the 'bubble test' (submerging the end of the tube in water) as the sole confirmation method — it is unreliable. Nasal mucosal injury (bleeding) can occur if excessive force is applied — apply lubricant and advance gently. Tube displacement is common, especially in young children who pull at the tube — secure carefully and re-verify placement before every feed. Coiling or looping of the tube in the pharynx (visible or palpable on examination) indicates the tube has not advanced to the stomach.
IV cannulation — complications and recognition:
Infiltration/extravasation is the most common complication — the cannula tip is outside the vein and fluid/drug leaks into subcutaneous tissue. Signs: swelling at the site, pain, infusion slowing. Stop the infusion and remove the cannula. With vesicant drugs (calcium gluconate, concentrated potassium, vasoactive amines, chemotherapy), extravasation can cause tissue necrosis — manage according to the specific antidote. Phlebitis presents as erythema, warmth, and tenderness along the vein — remove the cannula and change site. Air embolism is rare but serious — always prime infusion tubing fully before connecting and ensure no air bubbles in the line. Haematoma formation at the site occurs if the posterior wall of the vein is punctured — apply firm pressure for 2–3 minutes after failed attempts.
IO access — complications and recognition:
Extravasation is the most important IO complication — the needle has not entered the medullary cavity and fluid leaks into soft tissue. Signs: progressive swelling, loss of skin integrity, failure of infusion to run. Remove the needle, apply pressure, and retry at the same site (not recommended) or an alternative site (preferred). Osteomyelitis is a rare but serious delayed complication — prevented by removing IO access within 24 hours and using strict aseptic technique. Compartment syndrome can result from large-volume infiltration — monitor the limb for firmness, tightness, or increasing pain. Growth plate injury is avoided by using the correct site (1–2 cm below the tibial tuberosity on the flat anteromedial surface — NOT above the tuberosity).
| Complication | Procedure | Key sign | Action |
|---|---|---|---|
| Pulmonary misplacement | NG tube | Cough, cyanosis, pH >5 on aspiration | Remove tube immediately, re-insert |
| Extravasation | IV or IO | Swelling at site, slow infusion | Remove cannula/needle, apply pressure |
| Phlebitis | IV | Erythema, warmth, tenderness | Remove cannula, change site |
| Growth plate injury | IO | Incorrect landmark | Prevention: 1–2 cm below tibial tuberosity |
SELF-CHECK
A 2-year-old child in cardiac arrest requires emergency vascular access. Two attempts at peripheral IV cannulation have failed over 90 seconds. What is the next recommended step?
A. Continue attempting peripheral IV until a vein is found — IO access is a last resort
B. Insert a central venous catheter via the femoral vein
C. Proceed with intraosseous access in the proximal tibia
D. Give all emergency drugs via the endotracheal tube while continuing to attempt IV access
Reveal Answer
Answer: C. Proceed with intraosseous access in the proximal tibia
PALS (Paediatric Advanced Life Support) guidelines recommend IO access when 2 IV attempts fail or when 90 seconds have elapsed without IV access in a cardiac arrest. IO access provides access equivalent to central venous access — all PALS drugs (adrenaline, atropine, adenosine, amiodarone) and fluids can be administered via IO. It is the fastest, safest route in this scenario. Delaying to attempt further IV access or to insert a central line wastes critical resuscitation time. Endotracheal drug administration is no longer recommended as a primary route in PALS guidelines.
Applied and Supervised Practice
Procedural competence in paediatric interventions is built through deliberate practice on manikins followed by supervised clinical exposure. The manikin environment allows you to rehearse the physical feel of each procedure, develop procedural memory, and make errors without patient harm — this is the explicit purpose of simulation-based learning in medical education.
For NG tube insertion, the key simulation goals are: (1) correctly measuring the NEX distance and marking it on the tube before insertion; (2) reproducing the posterior directional technique at the nasopharyngeal turn (practise by inserting the tube at the base of the nares, not angled upward); (3) verification by aspiration and auscultation; and (4) correct tape fixation that prevents dislodgement. After simulation, aim to observe and then assist with NG insertion in at least 3 patients (neonates, infants, and older children have different tube sizes and nostril anatomy) before attempting unsupervised insertion.
For IV cannulation, the manikin task focuses on: (1) tourniquet placement and site selection — identify the vein before touching the skin; (2) the 10–15° insertion angle and recognising 'flashback'; (3) the two-step advance (needle then cannula) that prevents the common error of advancing the needle too far and piercing the posterior vein wall; and (4) secure fixation. In clinical practice, a supervised target of 5–10 cannulations across different age groups (neonate, infant, child) is the minimum for competence.
For IO access, the simulation goal is: (1) reliable identification of the tibial tuberosity and the correct insertion point 1–2 cm below and medial to it; (2) feeling the 'give' as the cortex is breached with the EZ-IO drill; (3) verifying placement by the needle standing upright and flushing freely. Clinical exposure to IO insertion will likely be rare but essential — practise on manikins regularly so the skill does not degrade.
A useful self-check before each supervised procedure: complete the relevant checklist mentally:
• NG tube: correct size calculated? NEX measured? Placement verified before feeding?
• IV: tourniquet applied? Site cleaned? Flashback seen? Flush smooth?
• IO: tuberosity identified? Insertion point 1–2 cm below? 'Give' felt? Needle upright? Flush without swelling?
SELF-CHECK
When securing an NG tube in a 9-month-old infant, which of the following is the safest method to confirm correct gastric placement before the first feed?
A. Bubble test — submerge the open end of the tube in water and check for bubbles
B. Ask the infant to confirm absence of coughing — no cough indicates correct placement
C. Aspirate gastric contents and test on pH paper — pH ≤5 confirms gastric placement
D. Auscultation alone — air insufflation with gurgling sound over the epigastrium
Reveal Answer
Answer: C. Aspirate gastric contents and test on pH paper — pH ≤5 confirms gastric placement
Aspiration of gastric contents tested on pH paper (pH ≤5) is the recommended primary method for confirming NG tube placement in clinical guidelines. The bubble test (submerging in water) is unreliable and cannot distinguish tracheal from gastric placement. Auscultation alone (epigastric gurgling with air insufflation) has poor specificity — air sounds may transmit from an oesophageal or tracheobronchial position. In an infant, absence of coughing does not confirm gastric placement as small-calibre NG tubes can enter the bronchus without triggering cough reflex. For ambiguous cases, a chest and upper abdominal X-ray is the gold standard.
Self-Assessment
The self-assessment section consolidates all three procedural skills covered in this module — NG tube insertion, IV cannulation, and IO access. Procedural competency requires not just knowing the steps but understanding the decision logic: when to choose each procedure, how to verify correct placement, and how to recognise and respond to complications. Review the key recall questions below and work through the micro-quiz scenarios that follow.
Before reviewing the answers, close your eyes and mentally simulate the complete procedure sequence for each of the three skills: what is the first thing you do, what is the critical verification step, and what are the two most important complications to monitor? This active recall strengthens procedural memory far more effectively than passive re-reading.
Key recall questions:
1. What are the indications and contraindications for NG tube insertion in a child?
2. What is the gold-standard bedside method for verifying NG tube placement?
3. After how many failed IV attempts (or how many seconds in arrest) should you switch to IO access?
4. Where exactly is the IO insertion site on the proximal tibia?
5. Name the most important complication of IO access and how it is prevented.
Answers: 1. Indications: enteral feeding when oral route is unsafe, SAM, altered consciousness; contraindications: basal skull fracture, oesophageal obstruction. 2. Aspiration with pH ≤5 on pH paper. 3. After 2 IV fails or 90 seconds in cardiac arrest. 4. 1–2 cm below the tibial tuberosity on the anteromedial flat surface (NOT above the tuberosity). 5. Extravasation/compartment syndrome from infiltration; prevented by verifying correct placement (needle upright, free flush without swelling) and removing IO within 24 hours.