Gastrostomy, tracheostomy and central-line troubleshooting — viva

Opening (must-hit)

"Troubleshooting a child's gastrostomy, tracheostomy or central line means recognising the failure mode and running the right algorithm after airway, breathing and circulation are secured. For the tracheostomy I run the National Tracheostomy Safety Project algorithm — suction, remove the inner cannula, deflate the cuff, remove the tube and ventilate — and I never force a tube down an immature tract, defined as within the first seven to ten days. For the gastrostomy I replace a tube that has fallen out of an immature tract (under six to eight weeks) within hours before it closes, and I recognise a buried bumper by leakage with resistance to feeding. For the central line I categorise occlusion as mechanical, thrombotic or a drug precipitate — a clot gets a weight-based alteplase dwell for two to four hours, a precipitate gets the matching solvent, and a fracture gets an immediate clamp between the child and the break." [4] [8] [12]

Branch A — The obstructed tracheostomy

Examiner: You are called to a 4-year-old with a tracheostomy who is desaturating. The suction catheter will not pass. What do you do? Candidate: The child comes before the device, so I assess airway and breathing first. I then run the National Tracheostomy Safety Project algorithm in order: I suction via the tracheostomy, which both clears secretions and tests patency. The catheter will not pass, so I remove the inner cannula and clean or replace it. If the child is still not oxygenating I deflate the cuff. If the obstruction persists I remove the tracheostomy tube and ventilate — by bag-valve-mask over the face if the upper airway is patent, or by a mask held over the stoma if it is not. I call for senior airway help early, and I do not persist with a non-functioning tube while the child deteriorates. [4]

Branch B — Decannulation and tract maturity

Examiner: The tube has fallen out entirely. The tracheostomy was inserted eight months ago. Walk me through your replacement. Candidate: The tract is mature — eight months is well beyond the seven-to-ten-day immature threshold — so I reinsert a tracheostomy tube of the same size with the obturator in place, gently and without force. If I meet resistance I use a tube one size smaller, which is why a spare of the same size and one smaller must be at every bedside. If neither passes I stop, ventilate, and call for help. I would not do this in the first seven to ten days: in that immature period the tract can create a false passage in the pretracheal tissues, so I ventilate by face mask, cover the stoma, and call the surgeon who created it. Wynings' cohort showed accidental decannulations cluster in the youngest and the newly tracheostomised, which is why that early period is guarded. [3]

Branch C — Central-line occlusion

Examiner: An oncology child's tunnelled line will neither flush nor withdraw. No fracture is visible. How do you work this up? Candidate: I categorise the occlusion, because the lock depends on the cause. This gradual, complete occlusion without a positional pattern most strongly suggests a thrombotic cause — a fibrin sheath or an intraluminal clot. A mechanical occlusion would be positional and would point to a kink, an over-tight suture, or the tip abutting a wall. A drug precipitate would follow an infusion of calcium, phenytoin or concentrated parenteral nutrition. For this thrombotic occlusion I instil alteplase in a volume that fills the lumen, weight-based — commonly 0.5 to 2 mg with the lower dose under 10 kg — dwell two to four hours, aspirate and flush, and repeat once. The Baskin data and Anderson's review showed this restores flow in the large majority of occluded paediatric lines. I do not force the line, because force can rupture the catheter or dislodge a clot. [8] [9]

Branch D — The fractured line

Examiner: You find a crack in the external segment of a central line, with blood at the site. What now? Candidate: That is a fracture, and the immediate risk is air embolism and blood loss. I clamp the line immediately between the child and the fracture using a slide clamp — never a haemostat, which can crush the catheter. If I suspect air entry I place the child head-down on the left side to limit embolism. I then prepare for repair with a manufacturer-specific kit if the fracture is clean and a kit is available, or replacement if it is not, recognising that a repaired line carries a higher infection and re-fracture risk. I monitor the child for air embolism and sepsis. [8]

Branch E — The dislodged gastrostomy

Examiner: A gastrostomy tube is lying on the bed. The child is two years old and the tube was inserted ten weeks ago. What do you do? Candidate: The tract is mature — ten weeks is beyond the six-to-eight-week immature threshold — so the tract will stay open for longer, but I still replace it without delay to be safe. I reinsert a device of the same size, or a Foley catheter as a temporising measure if the correct device is not to hand, and I confirm position before feeding — by aspirating and checking the pH (a gastric pH of 5.5 or below confirms gastric placement) or by a contrast study. I do not feed until position is confirmed. If this had been a tract under six to eight weeks old, I would replace it immediately because that tract closes within hours, and I would not feed until imaging confirmed position. [1]

Branch F — The buried bumper

Examiner: A gastrostomy that has been in for months is leaking, and the carer says the feeds meet resistance and the child cries. What is your diagnosis and action? Candidate: That presentation — leakage with resistance to feeding and pain in a long-standing tube — is buried bumper syndrome until proven otherwise. The internal balloon or bumper has migrated forward through the gastric wall and embedded in the mucosa, so the feeds meet tissue. I stop feeding and decompress the stomach, I do not force the tube, and I arrange a contrast study to confirm the diagnosis and then endoscopic or surgical correction. Forcing the tube would risk gastric perforation. I would distinguish this from a simple leak, which is usually mechanical and resolved by correcting the balloon volume and the bolster. [1]

Branch G — The late tracheostomy bleed

Examiner: Five weeks after a tracheostomy was formed, the family report bright red blood at the stoma, then a small gush. What is happening and what do you do? Candidate: That is a tracheoinnominate artery fistula until proven otherwise. A sentinel bleed of bright red blood in the second to sixth week after tracheostomy is the classic warning of an erosion between the trachea and the innominate artery, which crosses anterior to the trachea, and it can be followed by massive haemorrhage. This is a surgical emergency. I hyperinflate the cuff to tamponade if one is present, I withdraw the tube to reposition the cuff against the erosion, I apply firm digital pressure against the sternum to compress the innominate artery, and I call the surgical and anaesthetic teams while I secure the airway and large-bore access. I do not assume a late bleed is trivial granulation. [5]

Branch H — Infection and disposition

Examiner: The child with the tunnelled line now has a fever and no other focus. What is your plan? Candidate: I take paired peripheral and line-drawn blood cultures before antibiotics, I examine the exit site and the tunnel for erythema, pus and tenderness, and I start empiric antibiotics guided by local protocol and the likely skin-organism cause. I discuss salvage versus removal with the oncology and infectious diseases team — I attempt salvage of a tunnelled line where possible and remove it for septic shock, a tunnel infection, or persistent bacteraemia. After any device emergency I observe the child in a high-dependency or intensive-care setting, because the recurrence risk is highest in the hours immediately after. [12]