Gastrostomy, tracheostomy and central-line troubleshooting — formative SAQs

SAQ 1 (10)

A 4-year-old child with cerebral palsy and a tracheostomy for chronic lung disease desaturates to 80 per cent on the ward. The nurse cannot pass the suction catheter. The tracheostomy was inserted four months ago. [4]

1. Recite the National Tracheostomy Safety Project paediatric emergency algorithm you would run, in order. (5) [4]
2. The tube has fallen out entirely. How does your response differ from a tube that is merely obstructed, and how does tract maturity change what you do? (3) [3]
3. Forty minutes later the child stabilises. Four weeks after this event the family report a small amount of bright red blood at the stoma. What is your concern and your immediate action? (2) [5]

Model answer

National Tracheostomy Safety Project algorithm. The child comes before the device, so I assess airway and breathing first, then run the algorithm in order: I suction via the tracheostomy; if the suction catheter will not pass 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 a bag-valve-mask over the face if the upper airway is patent and the stoma is covered, or by a mask held over the stoma if the upper airway is not patent. I call for senior airway help early. The cardinal error is to persist with a non-functioning tube while the child deteriorates. [4]

Decannulation and tract maturity. If the tube has fallen out entirely, my priority is oxygenation while I decide on replacement. The response turns on tract maturity. This child's tract is mature — the tracheostomy was inserted four months ago, 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; if neither passes I ventilate and call for help. I do not apply this logic to an immature tract: within the first seven to ten days the tract is not established and blind instrumentation can create a false passage in the pretracheal tissues, so in that period I ventilate by face mask, cover the stoma, and call the surgeon or anaesthetist. [3]

Late bleed. Bright red blood at the stoma in the weeks after tracheostomy raises a tracheoinnominate artery fistula until proven otherwise. This is a surgical emergency. The immediate actions are to hyperinflate the cuff to tamponade, to withdraw the tube to reposition the cuff against the erosion, to apply firm digital pressure against the sternum compressing the innominate artery, and to 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]

SAQ 2 (10)

A 6-year-old oncology child with a long-term tunnelled central venous catheter has a lumen that will neither flush nor withdraw blood. There is no leak or fracture visible. The line has been in place for four months. [8]

1. Categorise the likely causes of central-line occlusion and state which bedside features point to each. (4) [8]
2. Give the thrombolytic dwell regimen you would use for a thrombotic occlusion, with its evidence, and state two alternatives for a non-thrombotic occlusion. (4) [9] [10]
3. Outline your central line-associated bloodstream infection prevention bundle, and state how you would investigate a fever with no other source in this child. (2) [12]

Model answer

Categorising central-line occlusion. Occlusion is mechanical, thrombotic, or a drug precipitate. A mechanical occlusion is suggested by a line that occludes with a positional change or has blood return in one position, and it points to a kink, an over-tight suture, a clamp, or the tip abutting a vessel wall. A thrombotic occlusion is suggested by a line that gradually lost withdrawal while still flushing, pointing to a fibrin sheath or an intraluminal clot. A drug precipitate is suggested by occlusion shortly after an infusion of calcium, phenytoin, or concentrated parenteral nutrition, where a high-pH or incompatible solution has crystallised in the lumen. This child's gradual, complete occlusion without a positional pattern most strongly suggests a thrombotic cause. [8]

Thrombolytic dwell and alternatives. For a thrombotic occlusion I instil alteplase in a volume that fills the lumen, at a weight-based dose — commonly 0.5 to 2 mg, with the lower dose reserved for the child under 10 kg — leave it to dwell for two to four hours, then aspirate and flush, repeating once if the first dwell fails. The Baskin data and Anderson's paediatric review established this regimen as effective and safe, restoring flow in the large majority of occluded paediatric lines with a low complication rate. For a non-thrombotic occlusion I would not use a thrombolytic: a mechanical cause is resolved by releasing a clamp, loosening an over-tight suture, repositioning the child or the arm, or repositioning the tip under imaging; a drug precipitate is resolved by the matching solvent — sodium bicarbonate for an alkaline precipitate such as calcium or phenytoin, or hydrochloric acid for an acidic precipitate. [9] [10]

CLABSI bundle and the fever workup. The prevention bundle is full barrier precautions at insertion, chlorhexidine skin antisepsis, a chlorhexidine-impregnated dressing, scrub-the-hub before each access, avoidance of routine flushing, and a daily review of line necessity with prompt removal. For a fever with no other source I take paired peripheral and line-drawn blood cultures before antibiotics, examine the exit site and tunnel, and 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, removing the line for septic shock, a tunnel infection, or persistent bacteraemia. [12]