Analgesia and Sedation of Critically Ill Patients
An essential goal of all critical care physicians should be to
maintain an optimal level of analgesia and sedation for their patients. There is
evidence that more than one half of patients cared for in the ICU recall unpleasant
memories of their ICU stay, including unrelieved pain, sleep deprivation, anxiety,
nightmares, and hallucinations.[123]
[124]
[125]
[126]
These
patients may also go on to experience post-traumatic stress disorder.[127]
Conversely, although inadequate sedation and analgesia are detrimental, excessive
sedation is also undesirable, because it may contribute to prolonged mechanical ventilation,
increased
ICU length of stay, and increased diagnostic testing for altered mental status.[128]
Sedation Scoring Scales
Titrating sedatives and analgesics to a specific behavioral target
allows optimization of dosing. Several validated and reliable scoring scales have
been developed to improve the delivery of sedation. The most frequently used scoring
systems include the Ramsay score, the Riker Sedation-Agitation Scale (SAS), and the
Motor-Activity Assessment Scale (MAAS). The Ramsay scale is a 6-point system ranging
from 1 for anxious to 6 for unarousable.[129]
Developed
in 1974, it unfortunately lacks behavioral descriptors to help clinicians assign
a score, and a single level can range from mild anxiety to dangerous levels of agitation.
[130]
Nevertheless, this is one of the most widely
used and validated scales. The Riker SAS was developed in 1994 and then revised
in 1999. It provides a symmetric approach to grading patient behavior with three
severity levels each for sedation and agitation and one level for the calm patient.
[131]
[132]
Behavioral
descriptors provide clinicians assistance with assigning scores. The MAAS was reported
in 1999 and is similar to the SAS scale. It also has three categories for sedation
and agitation and a middle level for calm and cooperative. The behavioral descriptors
are similar to the SAS, but the scoring starts from 0 instead of 1.[133]
[134]
Table
74-6
shows the three different scoring systems and their behavioral descriptors.
The benefit of using objective scoring systems to guide sedation
in the ICU is just beginning to be appreciated. Several studies are examining the
use of sedation scores and measuring outcomes such as length of stay, mortality,
need for paralytic agents, duration of ventilation, patient and family satisfaction,
and long-term psychological sequelae.[135]
Two
studies have attempted to address the use of sedation protocols in the ICU. Brook
and coworkers[136]
used a protocol-driven sedation
regimen for 321 ICU patients. Patients were randomized to a nurse-implemented protocol
for decreasing sedation or to a nonprotocol-directed sedation regimen. The results
were impressive; the protocol group had a 2-day reduction in the duration of continuous
sedation, a 50% reduction in the duration of mechanical ventilation, a 2-day reduction
in ICU length of stay, a 6-day reduction in hospital length of stay, and a 50% reduction
in the need for tracheostomy. Mascia and associates[137]
also showed that implementation of a sedation protocol resulted in reduced sedation,
analgesia, and neuromuscular blocking drug costs per day of ICU stay.
Sedative Interruption
Regardless of the sedation scoring system used, patients need
continuous reassessment of their sedation requirements. Kress and colleagues[128]
randomized 128 mechanically ventilated patients to have all sedatives interrupted
daily until the patients were awake, compared with their standard of care in which
the sedative infusions were left to the discretion of ICU clinicians. Patients in
the intervention group had decreased duration of mechanical ventilation (4.9 versus
7.3 days, P = .004) and decreased length of ICU stay
(6.4 versus 9.9 days, P = .02).
TABLE 74-6 -- Sedation scores and their behavioral descriptors
|
Score |
Response |
|
Ramsay Sedation Scale |
|
1 |
Anxious and agitated or restless, or both |
|
2 |
Cooperative, oriented, and tranquil |
|
3 |
Responding to commands only |
|
4 |
Brisk response to light glabellar tap |
|
5 |
Sluggish response to light glabellar tap |
|
6 |
No response to light glabellar tap |
|
Sedation-Agitation Scale |
|
7 |
Dangerous agitation. Patient pulls at endotracheal tube, thrashes,
climbs over bed rails. |
|
6 |
Very agitated. Patient does not calm, requires restraints, bites
endotracheal tube. |
|
5 |
Agitated. Patient attempts to sit up but calms to verbal instructions. |
|
4 |
Calm and cooperative. Patient follows commands. |
|
3 |
Sedated. Patient is difficult to arouse but follows simple commands. |
|
2 |
Very sedated. Patient arouses to stimuli but does not follow
commands. |
|
1 |
Unarousable. Patient has minimal or no response to noxious stimuli. |
|
Motor Activity Assessment Scale |
|
6 |
Dangerously agitated, uncooperative. No external stimulus is
required to elicit movement, and patient pulls at tubes or catheters, thrashes side
to side or strikes at staff, tried to climb out of bed, and does not calm down when
asked. |
|
5 |
Agitated. No external stimulus is required to elicit movement,
and an patient attempts to sit up or moves limbs out of bed and does not consistently
follow commands (e.g., lies down when asked but soon reverts to attempts to sit up
and move limbs out of bed). |
|
4 |
Restless and cooperative. No external stimulus is required to
elicit movement, and patient picks at sheets or tubes or uncovers self and follows
commands. |
|
3 |
Calm and cooperative. No external stimulus is required to elicit
movement, and patient adjusts sheets or clothes purposefully and follows commands. |
|
2 |
Responsive to touch or name. Patient opens eyes, raises eyebrows,
or turns head toward stimulus or moves limbs when touched or name is loudly spoken. |
|
1 |
Responsive only to noxious stimuli. Patient opens eyes, raises
eyebrows, or turns head toward stimulus or moves limbs in response to noxious stimulus
(e.g., suctioning; 5 seconds of vigorous orbital, sternal, or nailbed pressure). |
|
0 |
Unresponsive. Patient does not move with noxious stimulus (e.g.,
suctioning, 5 seconds of vigorous orbital, sternal, or nailbed pressure). |
The intervention group also required fewer diagnostic tests to assess changes in
mental status (9% versus 27% in the control group, P
= .02). Complications such as self-extubation were not different between groups.
Based on the previous data, the clinical guidelines published
by the Society of Critical Care Medicine and the American College of Critical Care
Medicine recommend that sedation protocols should be instituted and that they include
daily sedation interruption and patient-targeted goals for sedation and analgesia
administration.[138]
