Aim: This study examines the performance of healthcare professionals in a variety of high-pressure scenarios. Methodology: In order to gain a broad, detailed, practical understanding of ‘pressure’ and its impact on performance, a wide range of clinical scenarios were analysed using a Grounded Theory approach. A total of forty-five interviews were undertaken with key health professionals (medical doctors, nurses, paramedics) in a variety of locations including the Galapagos Islands, the Amazon Region, the Andean Highlands, and the Pacific Coast. Using participants as field observers, diverse scenarios were captured: emergency field work, natural disasters, emergency departments, large and small medical facilities, intensive care units and operating theatres. Results: The research took an ‘emic’ approach to understanding ‘pressure’, whereby participants identified scenarios that were important to them and how they experienced ‘pressure’ personally.