Heat exhaustion during mass pilgrimage--is there a diagnostic role for pulse oximetry?

Every year over 2 million pilgrims (Hajjis) gather from different countries to perform the sacred ritual, the fifth pillar of Islam, Hajj. Several nationalities from different climates come to Saudi Arabia which is located in a subtropical area with a hot and humid climate during the long summer season. This undertaking is characterised by several days of continuous physical, spiritual, and emotional exertion following their homeland. Several factors predispose them to heat exhaustion, such as the hot climate, excessive physical exercise, lack of acclimatisation, overcrowding, illiteracy, old age, diseases, and over zealous performance of Hajj during the peak sunshine hours. Several thousands of pilgrims suffer from heat exhaustion which is a minor form of heat illness that can easily be detected and treated. Patients are usually discharged having fully recovered, but if heat exhaustion is not treated immediately, it may result in heat stroke with serious sequelae. Cases that need further observation and management are admitted to hospital, particularly those who have associated medical disorders. This study was designed to investigate the role of pulse oximetry in detecting hypoxaemia in patients suffering from heat exhaustion. One hundred fifty-five patients from 26 different countries were enrolled in this study. Their ages ranged from 18 to 83 years. There were 51 (33%), 48 (31%), and 56 (36%) from Asia, the Middle East and Africa, respectively. One hundred thirty-four patients (86.5%) showed a form of hypoxia which necessitated O2 administration. Mild hypoxia (91-94% O2 saturation) was detected in 81 patients (52.3%) and moderate to severe hypoxia (< 90% O2 saturation) was detected in 53 (34.2%) patients.