Endpoints of Resuscitation

Abstract

If the aim of resuscitation is to restore life, as the above definition implies, the underlying pathophysiology which threatens existence must be understood. Whatever the mechanism of shock, the final common denominators are tissue ischaemia and anaerobic metabolism [1]. The reason why this pathophysiological state is lethal can be explained by basic physiology. The human is an aerobic organism and 90 % of consumed oxygen is used to produce adenosine triphosphate (ATP) via Kreb’s cycle. Manufactured by mitochondria within the cell, ATP is virtually the sole energy source for the myriad of energy requiring enzymatic reactions to maintain homeostasis. The human consists of four quadrillion cells in each of which there are thousands of mitochondria. On average only 100 g of ATP exist at any one time and cells turn over 10⁷ molecules of ATP per second, with each molecule being recycled every 20–30 s. This results in an average daily production of 100–150 kg of ATP per day. The molecular weight of ATP, which therefore contains Avogadro’s number or 6 × 10²³ molecules, is 0.5 kg and therefore the daily minimum production is at least twice this number, namely 12 × 10²⁵ molecules. How big is this number? It amounts to the number of cupsful of water in 200 Pacific Oceans. Little wonder then that shock, which disrupts oxygen delivery or utilisation at the cellular level, is a threat to life. Even for only a short period, shock results in marked depletion of ATP [2] and protracted episodes result in a profound physiological abyss from which there is no prospect of recovery.

“Resuscitare” [Latin transitive verb] “to bring back to life”