Page 165 - ACCCN's Critical Care Nursing

142 P R I N C I P L E S A N D P R A C T I C E O F C R I T I C A L C A R E

tissue damage reduce the threshold for activation of the Whenever patients cannot verbally communicate other
nociceptors. 89 strategies must be established and used consistently. For
example strategies involving nodding, hand movements,
Pain is transmitted to the central nervous system via one
of two pathways. The fast pain pathway occurs where the facial expressions, eye blinks, mouthing answers and
stimuli are carried by small myelinated A-delta fibres, writing can be highly effective, not only for the self-
producing a sharp, prickling sensation that is easily assessment of pain but also to express other feelings and
localised. The slow pathway acts in response to polymo- concerns. In extremely challenging cases when there is
dal nociceptors, is carried by small unmyelinated C fibres, very limited motor function but the patient is cognitively
and produces a dull, aching or burning sensation. It is able, the speech pathologist may be able to advise on
difficult to locate, acts after fast pain, and is considered alternative communication strategies.
to be more unpleasant than fast pain. 89 If at all possible, a history of the patient’s health status,
including any existing painful conditions, should be
Perceptions of pain are thought to occur in the thalamus, taken. A family member or close friend may be willing to
whereas behavioural and emotional responses occur in assist if the patient is unable to provide one. Quite apart
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the hypothalamus and limbic system. Perceptions of from the presenting condition which may be painful
pain are influenced by prior experience, and by cultural many critical care patients have significant co-morbidities
and normative practices, and help to explain individual such as rheumatoid/osteoarthritis and chronic back pain.
reactions to pain. 89
It is imperative that the patient’s usual pain management
There are negative physiological effects of pain that strategies are identified and implemented if possible. For
include a sympathetic response with increased cardiac example, factors that relieve the pain or increase its inten-
work, thus potentially compromising cardiac stability. sity should be recorded, along with its relationship to
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Respiratory function may be impaired in the critically ill daily activities such as sleep, appetite and physical ability.
undergoing surgical procedures where deep-breathing
and coughing is limited by increased pain, thus reducing Regardless of the patient’s communication capability,
airway movement and increasing the retention of strategies to ensure consistent objective assessment and
secretions and possibility of nosocomial pneumonia. management should be implemented. Laminated cards
Other known effects of unrelieved pain are nausea and displaying body diagrams, words to describe pain and
vomiting. pain intensity measures (including visual analogues and
numerical scales) are useful instruments in meeting these
Adverse psychological sequelae of poorly-treated pain requirements. Verbal numerical scale and visual analogue
include diminished feelings of control and self-efficacy scales (VAS) are commonly used. These are outlined in
and increased fear and anxiety. Inattention with an inabil- Table 7.6. Visual analogue scales can be difficult to
ity to engage in rehabilitation and health-promoting administer to critically ill patients however a combined
activities is not uncommon. Pain is commonly cited by VAS and numerical scale includes the benefit of a visual
patients as a significant negative memory of their ICU cue with the ability to quantify pain intensity.
experience. 85,86,91 The long-term effects of pain are not Other physiological and behavioural pain indicators may
clearly understood but they almost certainly impact on be used to assess pain in less responsive or unconscious
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recovery and may even lead to worsening chronic pain. patients. Research indicates that consistent assessment
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When these unwanted outcomes are considered along- of a number of indicators together provides an adequate
side the physiological effects of poorly treated pain, the substitute for self-assessments. 95,96 Several instruments
vital importance of pain management is evident.
have been developed and validated for use in the critically
ill adult patient including the Behavioural Pain Scale
PAIN ASSESSMENT (BPS) (see Figure 7.6), Checklist of Nonverbal Pain Indi-
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‘Pain is whatever the experiencing person says it is, exist- cators (CNPI) and the Critical Care Pain Observation
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ing whenever he says it does’. 93, p. 26 The nebulous quality Tool (CPOT) (see Table 7.6). Briefly, scores are assigned
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and subjective nature of the pain experience leads to to categories such as altered body movements, restlessness
considerable problems in assessing it. Compounding this and synchronisation with the ventilator, providing
is the challenge of assessment in the critically ill who a global score for comparison after pain relief interven-
often have insufficient cognitive acumen to articulate tions. The BPS is one of the most widely used scales for
their needs and an inability to communicate verbally. A use in patients unable to communicate verbally. 97,100,101
common language and process in which to assess pain is
essential in ameliorating some of these challenges. Fur- Nurses are urged against solely relying on changes in
thermore, accurate assessment and consistent recording physiological parameters, including cardiovascular (ele-
are fundamental aspects of pain management. Without vated blood pressure and heart rate) and respiratory
these vital components, it is impossible to evaluate inter- recordings, as other pathophysiological or treatment
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ventions designed to reduce pain. 94 related factors may be responsible. Classic reactions
such as increased heart rate and blood pressure, to stress-
Since the pain experience is subjective, all attempts should ors, e.g. pain, do not always occur in ICU patients and are
be made to facilitate the patient to communicate the therefore unreliable methods of assessing pain in this
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nature, intensity, body part and characteristics of their patient group. A potential explanation is that auto-
pain. For example the patient’s usual communication nomic tone may be dysfunctional in a large proportion of
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aids such as glasses and hearing aid should be used. ICU patients. In haemodynamically-stable long-term