The symptoms described as 'the chokes' in Type 2 Decompression Sickness are due to which mechanism?

• A. Air embolism in the pulmonary artery
• B. Non-cardiogenic pulmonary edema from activation of the inflammatory cascade
• C. Small air emboli in the alveolar-capillary membranes
• D. Air emboli in the CSF altering the responses of central chemoreceptors

Answer: (B)

The chokes are a pulmonary manifestation of Type II decompression sickness caused by an inflammatory response that leads to noncardiogenic pulmonary edema. When nitrogen bubbles form in the lungs during ascent, they trigger endothelial activation and release inflammatory mediators, making the pulmonary capillaries leaky. Fluid then accumulates in the interstitium and alveoli, producing dyspnea, cough, hypoxemia, and often crackles or frothy sputum, all without left-sided heart failure. This inflammatory edema explains why the mechanism is edema from capillary leak rather than simple air emboli obstructing the pulmonary arteries or effects on CSF and central chemoreceptors.