Chest decompression and intercostal drain insertion — formative SAQs

SAQ 1 (10 marks)

A previously well 8-year-old boy is brought to the emergency department after being struck by a car at speed. He is agitated, markedly tachypnoeic, and cyanosed. Examination reveals reduced air entry and hyperresonance over the right hemithorax, a trachea deviated to the left, and distended neck veins; his blood pressure is 70/40 mmHg. There is no time for imaging. [3] [4]

1. State the diagnosis and outline the immediate management, including the exact site and technique for needle decompression and why you would not wait for a chest radiograph. (4) [3]
2. Describe the definitive intercostal drain insertion that must follow: name the safe triangle borders, the bundle rule, and your drain size for this child. (3) [1]
3. Forty minutes later the drain is swinging and bubbling but the child's haemoglobin is now 72 g/L and 250 mL of blood has drained in the last hour. Outline your ongoing management and the indication for thoracotomy. (3) [9]

Model answer — SAQ 1

(1) Diagnosis and immediate needle decompression (4). The diagnosis is a right tension pneumothorax, made clinically from the combination of respiratory distress, hypoxia, reduced air entry and hyperresonance on the right, tracheal deviation away from the affected side, distended neck veins, and circulatory collapse. Tension pneumothorax is a clinical diagnosis — I decompress immediately and do not wait for a chest radiograph, because waiting costs venous return and the child is peri-arrest. I give high-flow oxygen, secure intravenous access, and give a 10 mL/kg isotonic crystalloid bolus while I decompress in parallel. I insert a large-bore (14 or 16 gauge) cannula at the second intercostal space in the mid-clavicular line on the right, or — increasingly preferred, especially in children — at the fourth or fifth intercostal space in the anterior axillary line within the safe triangle; the axillary site is preferred because the paediatric chest wall is thinner and more consistent there and the catheter is more likely to reach the pleural space. I insert perpendicular to the skin, advance until air rushes out (the hiss), withdraw the needle, and leave the cannula secured. The needle is only a bridge: a formal intercostal drain must follow within minutes. [3] [4] [5]

(2) Definitive drain — safe triangle, bundle rule, drain size (3). I place the definitive intercostal drain within the triangle of safety: the anterior border is the lateral edge of pectoralis major, the posterior border is the lateral edge of latissimus dorsi, the inferior border is the fifth intercostal space at the nipple line, and the apex is the base of the axilla. I enter in the fourth or fifth intercostal space in the anterior axillary line and I insert just above the rib below — the intercostal neurovascular bundle runs in the costal groove along the inferior border of the rib above, so passing above the lower rib keeps me clear of it. I use blunt dissection (never a trocar), keep a finger in the track, and connect immediately to an underwater seal with the tube tip two centimetres below the water line. For this 8-year-old with a traumatic pneumothorax and possible haemothorax I would choose a large-bore 28 to 32 French drain so that any blood does not clot and block the tube; if it were purely air I would use a small-bore 8 to 14 French pigtail. [1]

(3) Ongoing blood loss and the thoracotomy threshold (3). The combination of ongoing drainage, falling haemoglobin, and shock signals a significant haemothorax. I cross-match blood, transfuse to maintain perfusion, and reassess constantly. The indication for thoracotomy in a child is ongoing heavy blood loss — broadly, more than 2 mL/kg per hour of continued drainage, or a large initial volume — or haemodynamic instability despite drainage and transfusion. A prospective multicentre cohort analysis of traumatic haemothorax identified a large initial volume and persistent bleeding as the predictors of initial management failure that should trigger surgical review. I involve the trauma and thoracic surgical teams early and continue the ATLS primary survey for associated injuries. [9]

SAQ 2 (10 marks)

A 3-year-old girl is admitted with lobar pneumonia that has not improved after 48 hours of intravenous antibiotics. She has a swinging fever, pleuritic chest pain, and increased work of breathing. A chest radiograph and ultrasound show a large, loculated right parapneumonic effusion. The team plans an intercostal drain. [2]

1. Outline your pre-procedure assessment and the pleural fluid tests you would send when the drain goes in. (3) [2]
2. Describe the drain insertion technique, the drain size, and your analgesia plan including the weight-based maximum dose of plain lidocaine for this 15 kg child. (4) [1]
3. The collection is loculated. Outline the role of intrapleural fibrinolytics and the indication for video-assisted thoracoscopic surgery (VATS). (3) [2] [10]

Model answer — SAQ 2

(1) Pre-procedure assessment and pleural fluid panel (3). I confirm this is a complicated parapneumonic effusion or empyema: pneumonia not improving after 48 hours, swinging fever, pleuritic pain, and a loculated collection on imaging. I assess the severity — work of breathing, oxygen requirement, and signs of sepsis — and start or broaden intravenous antibiotics to cover Streptococcus pneumoniae and Staphylococcus aureus, sending blood cultures first. Before drainage I arrange a group and hold (mandatory, as drainage may bleed) and review the coagulation profile. When the drain goes in I send pleural fluid for pH, glucose, lactate dehydrogenase, protein, cell count and differential, Gram stain and culture, and pneumococcal and staphylococcal PCR; in the atypical or immunocompromised child I add acid-fast bacilli, fungal culture, and cytology. A low pH (under 7.2) and low glucose with high LDH confirm an empyema that needs drainage. [2]

(2) Drain technique, size, and weight-based lidocaine (4). I site the drain within the triangle of safety — anterior border the lateral edge of pectoralis major, posterior border the lateral edge of latissimus dorsi, inferior border the fifth intercostal space at the nipple line, apex the base of the axilla — entering above the rib below to avoid the neurovascular bundle in the costal groove. I use blunt dissection, never a trocar, keep a finger in the track, and direct the tip towards the base for fluid. For an empyema I choose a 16 to 24 French drain to handle thicker pus and combine it with intrapleural fibrinolytics for the loculations. For analgesia I infiltrate 1% lidocaine down to the parietal pleura; the maximum dose of plain lidocaine is 3 mg/kg, so for a 15 kg child the maximum is 45 mg, which is 4.5 mL of 1% lidocaine (10 mg/mL). I aspirate before each injection to avoid intravascular delivery, write the maximum milligrams and volume on the drape, and add procedural sedation with full monitoring because the child is stable enough. [1]

(3) Intrapleural fibrinolytics and the VATS indication (3). For a loculated empyema I add intrapleural fibrinolytics — urokinase or tissue plasminogen activator — through the drain to break down the septa, alongside intravenous antibiotics. A 2026 systematic review and meta-analysis found a benefit to earlier rather than later fibrinolytic administration, so I have a low threshold to start them once a loculated collection is recognised. If drainage fails, the lung does not re-expand, or the collection is multiloculated on imaging, I move to early video-assisted thoracoscopic surgery (VATS) to break down the loculations and decorticate. The choice between primary fibrinolytics and primary VATS remains debated and is partly resource-dependent, but either is preferable to a single drain alone in a multiloculated empyema. I never drain a very large effusion without pausing — I reassess after about 1.5 litres to prevent re-expansion pulmonary oedema. [2] [10]