In which class of hemorrhage does systolic blood pressure begin to decrease?

Systolic blood pressure begins to decrease in Class 2 hemorrhage. In the classification of hemorrhagic shock, the system typically categorizes the classes based on the estimated blood volume lost and the corresponding physiological responses.

In Class 0 (approximately 0-15% blood volume loss, or up to 750 ml), the body can maintain normal blood pressure as there is typically an adequate compensatory mechanism in place. Class 1 involves a blood volume loss of about 15-30% (up to 1,500 ml), which may lead to slight changes in heart rate and may not yet impact systolic blood pressure significantly.

Class 2, involving a 30-40% loss (approximately 1,500-2,000 ml), is where we start to see physiological decompensation, including a decrease in systolic blood pressure, as the body can no longer maintain adequate perfusion despite compensatory mechanisms like tachycardia.

Class 3 entails loss of over 40% blood volume (more than 2,000 ml), which results in marked hypotension and potentially life-threatening shock with significant decreases in blood pressure, among other severe physiological changes.

Overall, Class 2 is specifically notable for the onset