You can find a summary of information on this topic in the text below. Detailed information is available in video lectures and recommended literature. 

Hemorrhagic shock 

Definition: 

• Hemorrhagic shock is a type of hypovolemic shock which is caused by internal or external bleeding. 
• The typical causes of bleeding include GIT bleeding, traumatic bleeding, peripartum bleeding, rupture of aortic aneurysm...

Symptoms: 

• A: pale lips and oral mucose; in case of GIT bleeding, blood could be found in the oral cavity.
• B: tachypnoea, desaturation, hypoventilation, cyanosis, in case of hemothorax decreased or absent breath sounds above injured side.
• C: hypotension, tachycardia, prolonged CRT, oliguria or anuria; in case of intraabdominal bleeding, the peritoneal signs could be present.
• D: consciousness impairment, anxiety, confusion.
• E: cold sweating, pallor, hypothermia, visible blood.

Definition of massive bleeding: 

• The loss of more than one body volume within 24 hours or
• Loss of more than 50% of the patient's total blood volume in less than 3 hours or
• Blood loss excess of 150 ml per minute or
• The localization of the bleeding is life-threatening (e.g. pericardial space, brain...)

Diagnostics

1.) ABCDE approach - finding the organ dysfunction which could lead us to the possibility of bleeding (see signs of hemorrhagic shock above).

2.) Localization of the source of bleeding: 

• Visible bleeding (blood in oral cavity, external bleeding, fresh blood in drains...).
• Physical examination (diminished breathing sounds, peritoneal signs, unstable pelvis, per rectum in suspicion of GIT bleeding).
• Imaging according to physical examination and patient's history.

3.) Labs, especially blood count (a decrease in haemoglobin; and in platelets is the latter sign of bleeding) and coagulation tests (standard tests or viscoelastic assays), should be performed. Liver tests, renal panel, ions, and arterial blood gas analysis should be performed from biochemistry. The ionized calcium is important for coagulation function, and lactate is important for the prediction of the state of microcirculation. Examining the patient's blood type is important for proper hemo substitution and order crossmatching. 

Therapy: 

1.) The essential step is to stop the bleeding as soon as possible.

2.) Similarly, apply the ABCDE approach and "treat as you go" rule.  Do not forget to cannulate at least two large peripheral IV lines. 

3.) Start the IV/IO fluids with a fluid bolus of balanced crystalloids to prevent intravascular hypovolemia. 

4.) If the hypotension persists even after fluid resuscitation, start the vasopressors to maintain perfusion pressure. The first line drug is noradrenaline, given in continuous infusion. In most cases, aim for a systolic pressure of 80-90 torr, which should be sufficient for vital organ perfusion and, at the same time, doesn't aggravate the blood loss.