Page 562 - ACCCN's Critical Care Nursing

Management of Shock 20

Margherita Murgo
Gavin Leslie

While the cause of shock may be multifactorial, treatment
Learning objectives focuses on optimising tissue perfusion and oxygen de-
livery. Shock is often classified according to the primary
After reading this chapter you should be able to: underlying mechanism: a disruption of intravascular
● describe the clinical manifestations of shock blood volume, impaired vasomotor tone or altered
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● distinguish between the various shock states cardiac contractility. The shock syndrome is one of the
● describe general principles of shock management most pervasive manifestations of critical illness present
● identify appropriate monitoring for a patient with shock in intensive care patients.
● review and evaluate care for a patient with a specific shock Early detection and management of shock to reverse
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type pathological processes improves patient outcomes.
Although the traditional hallmark of shock is hypoten-
sion (SBP <90 mmHg) this can be a late or misleading
sign and is considered a medical emergency. It is there-
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fore critical that other signs and symptoms are identified
Key words early by frequent observations to detect a patient’s dete-
riorating state and respond before irreversible shock
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anaphylactic shock ensues. No one vital sign is adequate in determining the
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cardiogenic shock level or extent of shock nor is there a specific laboratory
distributive shock test which diagnoses the shock syndrome.
hypovolaemic shock This chapter provides an overview of the pathophysiology
neurogenic shock of shock, the commonly described categories and associ-
obstructive shock ated pathologies, along with appropriate monitoring and
sepsis interventions for managing a patient in shock.
septic shock
severe sepsis PATHOPHYSIOLOGY
systemic inflammatory response syndrome
Traditionally, shock is classified by aetiology: hypovolae-
mic, cardiogenic and distributive. 3,4,9 Each has a specific
mechanism of action that leads to altered tissue perfusion
INTRODUCTION and oxygen and nutrient uptake at the cellular level (see
Table 20.1). In practice, it is common to find overlap
between different shock types (e.g. in sepsis there may
It is a bad symptom when the head, hands, and feet are cold, also be hypovolaemia and/or myocardial dysfunction).
while the belly and sides are hot, but it is a very good symptom
when the whole body is equally hot Shock occurs when there is an inability of the body to
The Book of prognostics by Hippocrates, 400 BC 1 meet metabolic demands of the tissues; hypoperfusion
(decreased blood flow to the tissues) results in cellular
Shock is an altered physiological state that affects the
functioning of every cell and organ system in the body. It dysfunction, as there is homeostatic imbalance between
4,10
is a complex syndrome reflecting changing blood flow to nutrient supply and demand, and adaptive responses
body tissues with accompanying cellular dysfunction and can no longer accommodate circulatory changes. These
eventual organ failure. Shock presents as a result of adaptive responses are moderated via numerous ‘sensors’
2,3
impaired nutrient delivery to the tissue: throughout the thorax and large vessels in particular,
which detect subtle changes in pressure (baroreceptors)
● when compensatory mechanisms can no longer or biochemical changes (chemoreceptors). These recep-
respond to decreases in tissue perfusion 4 tors feed back to the hypothalamus which regulates
● nutrient uptake is impaired at the cellular level. through the pituitary gland (for the release of a number 539