TABLE 1.

Classification of haemorrhagic shock.

Parameter	Class I	Class II	Class III	Class IV
Blood loss (% blood volume)	15	15–30	31–40	> 40
Pulse rate	< 100	100–120	120–140	> 140
Systolic blood pressure	Normal	Normal	Decreased	Decreased
Pulse pressure	Normal or increased	Decreased	Decreased	Decreased
Respiratory rate	14–20	20–30	30–40	> 35
Urine output (ml/hr)	> 30	20–30	5–15	Negligible
Mental state	Slightly anxious	Mildly anxious	Anxious, confused	Confused, lethargic
Base deficit	0 mEq/L to – 2 mEq/L	−2 mEq/L to – 6 mEq/L	−6 mEq/L to – 10 mEq/L	−10 mEq/L or less
Need for blood products	Monitor	Possible	Yes	Massive Transfusion Protocol

Source: Mutschler M, Nienaber U, Brockamp T, et al. A critical reappraisal of the ATLS classification of hypovolaemic shock: Does it really reflect clinical reality? Resuscitation. 2013;84(3):309–313. https://doi.org/10.1016/j.resuscitation.2012.07.012