Chapter 7: Shock

INTRODUCTION

Shock is defined as a life-threatening condition of acute circulatory failure leading to hypotension and mean arterial pressure (MAP) of less than 65 mm Hg. Due to its high mortality rate, shock should be intervened as soon as recognized as it can progress to irreversible organ failure.

Shock is classified as four major categories, namely vasodilatory (distributive), cardiogenic, hypovolemic, and obstructive. Some degree of overlap exists between each type of shock. Any sustained hypotension should be considered for diagnosis of shock, especially when the MAP is consistently less than 65 mm Hg, which increases risk of end organ damage leading to multi-organ failures.^1–3

Large volume fluid resuscitation has been traditionally thought to be the cornerstone for treatment of shock but was later shown to increase mortality and morbidity. Over time, a more conservative approach has been established that is thought to be life-saving and critical in decreasing mortality in patients with shock.⁴

PREVALENCE OF SHOCK DURING WAR

It was not until the 19th century that shock was described as a distinct entity from specific injuries themselves and more efforts were made to direct treatment for the shock.⁵ In addition to hemorrhagic shock,⁵ septic shock, disseminated intravascular coagulation, and multi-organ failure have been discussed from studies during World War II, the Korean War, and the Vietnam War.^5,6

Trauma has been linked to war and the first trauma care center in the United States was started in 1966.⁶ Since then, improved understanding of hemodynamics have led to improved outcomes.^7–9

PREVALENCE OF SHOCK DURING PANDEMICS

In the known pandemics such as SARS, MERS-CoV, COVID-19, influenza, plague, tularemia, and hemorrhagic fevers, there are various mechanisms of shock and they are associated with poor prognosis.^10–26

PREVALENCE OF SHOCK IN NATURAL DISASTERS

A disaster is defined by the Centre of Research on the Epidemiology of Disasters (CRED) as “a situation or event which overwhelms local capacity, necessitating a request to a national or international level for external assistance; an unforeseen and often sudden event that causes great damage, destruction and human suffering.”²⁷ WHO defines sudden-onset disasters (SODs) as disasters “for which there is little or no warning.”²⁸

In the last 10 years, natural disasters have killed 760,000 people, injured 2 million, and affected more than 2 billion.²⁹ On the average, 68,000 lives per year are lost due to natural disaster, or 0.1% of all the world’s population. Natural disasters are subdivided into two main categories: slow-onset natural disasters (SODs) and slow-onset natural disasters.

The true prevalence of shock in any specific natural disaster is extremely variable, and depends on the nature and ferocity of the disaster and on the sequelae of the disaster. Shock can develop rapidly, ...