Page 242 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

146 PART 2: General Management of the Patient

Effective analgesia is extremely important and is discussed in detail because physical barriers and delirium in the ICU are common occur-
in a later section of this chapter. Dyspnea is common in ICU patients rences. Concern over addiction to opiates, adverse cardiopulmonary
20
5
and may be a source of distress. Excessive coughing may contribute effects of analgesics, and arbitrary limits placed on drug doses may be
to patient-ventilator dyssynchrony. Opiates may alleviate dyspnea and other reasons for inadequate analgesia in the ICU.
coughing, particularly in intubated patients. Excessive oxygen consump- Certainly, the assessment of pain in critically ill patients can be chal-
.
tion (V O 2 ) and related carbon dioxide production (V CO 2 ) may be detri- lenging. As mentioned earlier, even the recognition of pain in these
mental in patients with respiratory failure or shock, and restoration of patients may be impaired by communication problems because many
the delicate balance of oxygen delivery and consumption is important are intubated and/or delirious. Tools to categorize pain, such as scales or
in the management of these patients. Oxygen consumption in intubated scoring systems, may be beneficial. In general, simpler scales are more
patients who are agitated can be reduced by 15% after administration of effective because communication for many ICU patients is limited.
sedatives and opiates. For those with shock or severe hypoxemic respi- The Visual Analogue Scale (VAS) has been found to have very good
1
ratory failure, this reduction in oxygen consumption may be important reliability and validity, 21,22 although it has not been evaluated specifi-
for cardiopulmonary stability. The importance of amnesia during criti- cally in critically ill patients. This scale is a self-report measure of pain
cal illness is not well understood. Although it may seem intuitive that intensity that typically consists of a 10-cm line on paper with verbal
amnesia for the period of critical illness is desirable, data supporting anchors (“no pain” and “severe pain”) on the ends. A similar scale is
this notion are lacking. Certainly it seems logical that amnesia for short the Numeric Rating Scale. This scale also consists of a horizontal line
periods (eg, during unpleasant interventions such as bronchoscopy) with numeric markings 1 and 10 anchoring either extreme of the pain
may be desirable; however, there are some data suggesting that complete intensity scale. 23,24 It may be preferred because it can be completed by
amnesia for prolonged periods (eg, for the entire period of mechani- writing, speaking, or hand gestures and may be better across various
cal ventilation) may be detrimental, leading to worse outcomes. age groups. Pain in the ICU is difficult to assess since there are many
2-4
7,8
As discussed later, it is certain that amnestic effects are desirable and limitations in the patient’s ability to self-report. The behavioral pain
considered mandatory during the administration of neuromuscular score (BPS) and the critical care pain observation tool (CPOT) are both
blocking agents. Delirium—an acutely changing or fluctuating mental validated in patients that are unable to communicate their pain due to
status, inattention, disorganized thinking, and an altered level of con- mechanical ventilation. These tools utilize behavioral or physiological
sciousness that may or may not be accompanied by agitation—is common responses in order to assess pain such as facial expression, body move-
in ICU patients and can present in up to 80% of mechanically ventilated ments, muscle tension, compliance with the ventilator if intubated, and
ICU patients. The pathophysiology of delirium is multifactorial and vocalization if extubated. 11
5,6
may occur as a result of medications, sepsis, fevers, encephalopathy Previous studies have shown that benzodiazepines may enhance the
(eg, hepatic or renal), paranoia, or withdrawal syndromes (alcohol, analgesic effects of opiates 22,23 and that opiate requirements are decre-
tobacco, or illicit drugs). Some patients may manifest an aggressive type ased in patients sedated with benzodiazepines rather than propofol.
1
of delirious behavior that may respond well to neuroleptic medications Notwithstanding this interesting observation, it is imperative that
such as haloperidol and/or quetiapine. The most common form of sedative agents are not used in the place of analgesics. The 2013 Clinical
7,8
delirium is the hypoactive, quiet form. There is no currently established Practice Guidelines for the Management of Pain, Agitation, and Delirium
pharmacologic therapy for hypoactive delirium, although sedative in Adult Patients in the Intensive Care Unit published by the Society of
medications are likely to exacerbate rather than alleviate the problem. Critical Care Medicine (SCCM) recommend a concept termed analgose-
dation, which promotes lighter sedation whenever possible. There are
ANALGESIA some specific instances where deeper sedation may be warranted, such
as pharmacological paralysis, alcohol or substance abuse withdrawal,
It is undeniable that pain is a common experience for most ICU procedures and ventilator dyssynchrony. Analgosedation is preferred
7
patients. 2,5,7-9 Approximately 80% of patients recall moderate to severe over a sedative-hypnotic approach because it may optimize analgesia and
pain in the ICU. A recent study evaluated pain in the ICU for up to limit administration of sedatives once analgesics have been provided.
10
14 days. They found that mild to moderate pain was identified in only The proposed benefit of analgosedation is that it may limit the admin-
40% of the patient assessments. 7,11,12 Failure to recognize that pain fre- istration of sedatives and reduce the risk of negative short-term and
quently leads to agitation may lead to inappropriate administration of long-term neurocognitive and neuromuscular deficits. 25
nonanalgesic sedatives. Accordingly, an aggressive approach to managing Although nonpharmacologic analgesic strategies are worth consider-
pain has been strongly recommended by published consensus opinions ing, they are frequently ineffective in dealing with pain in ICU patients.
regarding sedation in the ICU. 7,8,13 Addressing analgesic needs frequently Nevertheless, malpositioning of invasive catheters (eg, endotracheal tube
poses a challenge to the critical care clinician. The ability to discern pain impinging on the main carina) is a problem that may be remedied easily.
accurately may be difficult because many clinical parameters such as Likewise, optimal patient positioning in bed may relieve, at least in part,
changes in vital signs are sensitive but not specific indicators. There are low back pain, pain from chest tubes, etc. Despite appropriate attention
numerous reasons for pain in the ICU patient. While causes such as sur- to nonpharmacologic approaches, most patients require administra-
gical incisions or trauma may be obvious, other causes such as endotra- tion of some pharmacologic agents, with opiates being the mainstay
cheal suctioning or invasive catheters may be less apparent. Other causes of therapy. Strategies for administration include continuous infusions
of pain include pain from preexisting diseases (eg, vertebral compression and intermittent dosing strategies. Among the intermittent dosing
fractures from multiple myeloma), endotracheal tubes, and prolonged strategies are scheduled intermittent opiate administration, administra-
immobility during bed rest. Pain is a dynamic sensation and patient tion on an “as-needed” or PNR basis, and patient-controlled analgesic
9,14
specific. Treatment should be viewed as a spectrum based on physical (PCA) “as needed.” Intravenous rather than intramuscular injection is
assessment, rather than applying a formulaic approach. the preferred route of administration because intramuscular injections
Pain may result in many adverse effects, including increased end oge- themselves may be painful, and absorption of a drug given intramuscu-
nous catecholamine activity, myocardial ischemia, hypercoagulability, larly is frequently sporadic in critically ill patients. Patients alert enough
hypermetabolic states, hyperglycemia, sleep deprivation, anxiety, to respond to their own pain needs may benefit from PCA strategies.
and delirium. Adequate analgesia may diminish some of these detri- Transdermal opiates may be continued in patients who are chronically
15
mental effects. 16 receiving such medications; however, absorption is often unreliable
It is sobering to note that pain is treated inadequately in many differ- during critical illness. Therefore, this route should not be used for treat-
ent medical care settings, including the critical care unit. 18,19 Ineffective ing acute pain in the ICU; conversion to transdermal medications toward
17
communication with patients is sometimes at the root of this problem the end of a bout of critical illness is sometimes a reasonable approach.

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