Page 437 - ACCCN's Critical Care Nursing

Neurological Assessment

16 and Monitoring

Di Chamberlain
Leila Kuzmiuk

INTRODUCTION
Learning objectives
The nervous system is the major controlling, regulatory
and communicating system in the body. It accounts for a
After reading this chapter, you should be able to:
● describe the anatomy and physiology of the nervous mere 3% of the total body weight, yet it is the most
system complex organ system. It is the centre of all mental activ-
● differentiate between the central and peripheral nervous ity, including thought, learning and memory. Together
with the endocrine and immune systems, the nervous
systems system is responsible for regulating and maintaining
● describe the techniques used for neurological assessment homeostasis. Through its receptors, the nervous system
● identify the distinction between normal and abnormal keeps in touch with the environment, both external and
findings internal. Diseases of the nervous system are common in
● state the determinants of intracranial pressure and describe the critical care unit, both as primary processes and as
compensatory mechanisms used to prevent large changes complications of multiple organ failure in the critically
in intracranial pressure when there are changes in brain, ill patient. An understanding of basic neurophysiology is
blood and cerebrospinal fluid volumes important if these disorders are to be recognised and
● explain the importance and process of continuous treated. This chapter provides an overview of the anatomy
neurological assessment in the brain-injured patient and physiology, describes common pathophysiological
● relate the procedures of selected neurodiagnostic tests to processes, and details the management of alterations in
nursing implications for patient care the nervous system.

NEUROLOGICAL ANATOMY
AND PHYSIOLOGY

COMPONENTS OF THE NERVOUS SYSTEM
The central nervous system (CNS) consists of the spinal
cord and the brain and is responsible for integrating, pro-
cessing and coordinating sensory data and motor com-
Key words mands (see Figure 16.1). The CNS is linked to all parts of
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the body by the PNS which transmits signals to and from
central nervous system the CNS. The human PNS is composed of 43 pairs of spinal
peripheral nervous system nerves that issue in orderly sequence from the spinal cord,
intracranial pressure and 12 pairs of cranial nerves that emerge from the base
efferent neuron of the brain. All branch and diversify prolifically as they
afferent neuron distribute to the tissues and organs of the body. The periph-
autonomic nervous system eral nerves carry input to the CNS via their sensory afferent
sympathetic nervous system fibres and deliver output from the CNS via the efferent
fibres. Specific physiology of the CNS and PNS is discussed
parasympathetic nervous system in detail later in the chapter. First, however, neuron cell
Glasgow Coma Scale anatomy and physiology is examined.
neurological assessment
post traumatic amnesia Neurons
decorticate (flexor) Neurons are specialised cells in the nervous system; each
decerebrate (extensor) is comprised of a dendrite, cell body (soma) and axon.
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414 Each neuron is a cell that uses biochemical reactions to