Stab Wound to the Right Chest with Hemodynamic Collapse
A 28-year-old male arrives at the emergency department 30 minutes after a knife wound to the right anterior chest at the fourth intercostal space, midclavicular line. He is anxious, diaphoretic, and speaking in short phrases. Vital signs: BP 82/54 mmHg, HR 132/min, RR 34/min, SpO2 86% on room air. The right hemithorax is hyperresonant to percussion, breath sounds are absent on the right, and the trachea is deviated to the left. Neck veins are distended, but heart sounds are normal and there is no pulsus paradoxus. A chest tube tray and needle decompression kit are available. The nearest senior surgeon is 20 minutes away. The patient has no known allergies and no prior cardiopulmonary disease. You must decide the immediate bedside action and explain the anatomical rationale for the findings.
1. What is the most likely diagnosis, and how do the physical findings differentiate it from cardiac tamponade?
Read the worked answer
Most likely diagnosis: right-sided tension pneumothorax. The stab wound creates a pleural defect; air enters during inspiration and cannot exit, so intrapleural pressure rises. This explains hyperresonance and absent breath sounds on the right, hypoxia, hypotension, distended neck veins, and leftward tracheal deviation. Cardiac tamponade also causes hypotension and distended neck veins, but it produces muffled heart sounds, pulsus paradoxus, and no hyperresonance; tracheal shift is not expected. Normal heart sounds and absent pulsus paradoxus here favor tension pneumothorax. The tracheal deviation reflects mediastinal shift away from the pressurized hemithorax, not a primary airway problem. Immediate decompression is required before imaging because the patient is unstable.
2. Where should immediate needle decompression be performed, and what anatomical structures must the needle pass through?
Read the worked answer
Perform needle decompression at the right fifth intercostal space in the anterior axillary line, just above the rib, or at the second intercostal space in the midclavicular line according to local protocol. The anterior axillary approach is often preferred because the chest wall is thinner and the internal thoracic vessels are avoided. The needle traverses skin, subcutaneous fat, pectoralis major or serratus anterior depending on site, intercostal muscles, and parietal pleura. Staying just above the rib avoids the intercostal artery, vein, and nerve that run under each rib. A hiss of air confirms entry; leave the catheter in place and arrange tube thoracostomy. Avoid the inferior border of the rib and the parasternal area where the internal thoracic vessels run.