Expsr to chng in air pressure in arcrft during ascent, subs

This code signifies a patient's adverse reaction or injury resulting from a rapid alteration in atmospheric pressure experienced within an aircraft during its upward trajectory. It specifically pertains to a follow-up encounter for such an event, indicating that the initial assessment has already occurred. The physiological effects can range from barotrauma to more systemic responses.

Apply this code for subsequent visits where a patient is being treated or monitored for conditions directly attributable to sudden pressure changes during an aircraft's ascent. This includes follow-up appointments for ear pain, sinus issues, dental barotrauma, or other pressure-related injuries sustained during a flight. It is appropriate when the initial encounter for the injury has already been coded.

• Ensure this is a subsequent encounter; for the initial encounter, use the appropriate 7th character "A".
• Always code the specific manifestation of the injury (e.g., otitis media, sinusitis) first, followed by this external cause code.
• Verify the incident occurred during the ascent phase of the flight, as other phases (descent, cruising) have different codes.