Vital signs after haemorrhage - Caution is appropriate

Clinicians rely on a patient's vital signs, especially heart rate and blood pressure to assess the magnitude of haemorrhage in patients presenting with shock due to traumatic injury or other causes. Conventional wisdom is that HR rises proportionally to the volume of blood loss. This conventional wisdom is useful but can be misleading, especially in the absence of significant tissue trauma. The physiological responses to haemorrhage are complex and patients who have suffered significant haemorrhage may not present with tachycardia. (C) 2015 Elsevier Ltd. All rights reserved.