• Users Online: 2413
  • Print this page
  • Email this page

 Table of Contents    
Year : 2011  |  Volume : 55  |  Issue : 6  |  Page : 553-555  

Sedation in intensive care unit patients: Assessment and awareness

Department of Anaesthesia, Mysore Medical College and Research Institute, Mysore, Karnataka, India

Date of Web Publication5-Dec-2011

Correspondence Address:
C L Gurudatt
Department of Anaesthesia, Mysore Medical College and Research Institute, Mysore, Karnataka
Login to access the Email id

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0019-5049.90607

Rights and Permissions

How to cite this article:
Gurudatt C L. Sedation in intensive care unit patients: Assessment and awareness. Indian J Anaesth 2011;55:553-5

How to cite this URL:
Gurudatt C L. Sedation in intensive care unit patients: Assessment and awareness. Indian J Anaesth [serial online] 2011 [cited 2021 Mar 8];55:553-5. Available from: https://www.ijaweb.org/text.asp?2011/55/6/553/90607

There has been an increase in the number of patients who are placed on mechanical ventilators as more numbers of hospitals in India have started maintaining intensive care units (ICU) equipped with ventilators.

These patients in the ICU on mechanical ventilators require sedation and analgesia in order to tolerate the endotracheal tube, to lie down in the same position for a long time, to prevent dysynchrony with the ventilator, to tolerate many of the procedures, for optimization of oxygenation and for patient safety. [1]

Nevertheless, providing patients with an optimal level of sedation is a challenging act. Patients who are inadequately sedated are more likely to remain anxious, experience ventilator dysynchrony, remove invasive devices and experience post-traumatic stress disorder. [1] Other problems arising from undersedation are increased stress symptoms such as hypermetabolism, sodium and water retention, substrate mobilization from energy stress and lipolysis, cardiovascular symptoms including tachycardia, increased blood pressure, increased oxygen consumption, altered respiratory rates, altered gastrointestinal motility, changes in coagulability such as clotting time, platelet aggregation and delayed wound healing. [2]

Conversely, patients who become oversedated are more difficult to liberate from mechanical ventilation and thus are at greater risk for developing complications such as ventilator-associated pneumonia and each extra day on ventilator costs substantial amount to the patient. [1] Excessive sedation can also contribute to hypotension, venous thrombosis, prolonged ventilation, an increased risk for pneumonia and a prolonged stay in the ICU, with an increasing burden on staff, bed availability and associated costs. [3] Quimet et al. have identified a higher incidence of delirium and death in patients who develop drug-induced coma during their ICU stay. [4]

It is very important to optimize sedation and analgesia for these patients on mechanical ventilators. The role of the nursing staff is very crucial in this aspect to assess the level of sedation.

Many methods have been used to assess the sedation level of patients in ICUs. Both objective methods like electroencephalogram (EEG), auditory evoked potential and signal-processed EEG - bispectral index (BIS) monitors [5] and subjective methods in the form of sedation scores like Riker sedation-agitation scale (SAS), motor activity assessment scale (MAAS), richmond agitation-sedation scale (RASS), Adaptation to the intensive care environment scale (ATICE), Ramsay Sedation Scale and, more recently, Marak A Mirsky et al. have introduced the nursing instrument for the communications of sedation (NICS) and level of arousal (LOA). [6]

Although many scoring systems are available, few if any health professional can recall any scale in its entirety or score a patient without direct review of a scale's ordinal parameters. [6] The NICS scale [Table 1] appears to be a simple scale and can be easily followed by the nursing staff. Marek A Mirsky et al.[6] compared the utility of the NICS against other established scales - SAS, Ramsay and MAAS. The authors concluded that NICS ranked highest in nursing preference and ease of communication and may thus permit more effective and interactive management of sedation.
Table 1: Nursing instrument for the communication of sedation score response[6]

Click here to view

Because a majority of the sedation scales are subjective, many of the intensivists feel strongly that an objective monitor of sedation is crucial for adequately assessing the status of a patient.

The bispectral index monitor (BIS) was developed in the 1990s to monitor the effects of anaesthetics and other drugs on the brain during surgery, [7] BIS monitoring has been used as an objective measure of sedation in ICU patients . Numerous studies have been conducted in the past decade to determine the role of BIS monitoring of sedation in adult patients in the ICU. [8],[9],[10],[11],[12] Many studies have concluded that BIS monitoring was not helpful in assessing the level of sedation in ICU patients. [2],[9] Deogaonkar et al., [10] Consales et al.[11] and Arbour [12] have recently concluded that BIS is useful in the ICU setting. The main problem of using BIS for sedation in the ICU is that significant electromyographic (EMG) activity may be present in sedated, spontaneously breathing patients, which interferes with EEG signal and BIS calculation. The EMG activity may be interpreted as high-frequency, low-amplitude waves falsely elevating BIS. Similarly, falsely elevated BIS values can also occur with high electrode impedances produced by inadequate electrode attachment and misplacement. [13] Because of this, patients may be given unnecessary extra sedation. The newer version of BIS XP was designed to minimize EMG influence by detecting and filtering the interference. Deogaonkar et al.[10] found that BIS XP was useful in monitoring sedation in brain-injured patients, whereas Tonner et al.[14] found that the newer version was not useful for monitoring sedation in post-operative ICU patients.

Gelinas et al.[15] conducted a pilot study to explore the validity of BIS, the critical care pain observation tool (CPOT) score and vital signs (mean arterial pressure, heart rate) during rest and painful procedures in sedated and mechanically ventilated patients, and found that both BIS and CPOT scores are increased, but the vital signs remained quite stable during painful procedures. They concluded that CPOT score can be used in non-verbal patients to detect pain. However, when the patient is onmuscle relaxants, BIS seems to be an interesting tool.

BIS monitoring may be of special benefit when oversedation has to be avoided because clinical scales do not allow a discrimination of deep sedation. A deeper degree of sedation cannot be differentiated by clinical scales alone, whereas BIS can discriminate the level of sedation even down to a burst-suppression EEG. [2]

   Daily Interruption of Sedatives Top

Kress et al.[16] tested to determine whether daily interruption of sedative infusions in critically ill patients receiving mechanical ventilation would decrease the duration of mechanical ventilation (MV) and the intensive care unit length of stay (ICU LOS) and in the hospital stay. They found that daily interruption of sedative infusions reduced the duration of MV and ICU LOS. There was a concern that stopping sedation may expose patients to long-term psychological harm in the form of post-traumatic stress disorder (PTSD). [17] But, later studies have found that there is no increase in PTSD with daily spontaneous awakening trials (SATs). [18],[19] Jackson et al.[18] found that, compared with usual care sedation and ventilation weaning practices, a wake up and breathe protocol that pairs daily SATs (i.e., interruption of sedatives) with spontaneous breathing trials resulted in similar cognitive, psychological, functional and quality-of-life outcomes amongpatients tested 3 and 12 months after their ICU stay.

Contrary to traditional thinking, sedative medications may contribute to adverse psychological outcomes rather than prevent them. Jones and colleagues [20] demonstrated that patients who experience sedative-induced delusions while in the ICU, for example, are more likely to develop PTSD than patients who have factual memories of their ICU stay. Higher doses of benzodiazepines have been associated with PTSD symptoms months after discharge. [21] Recently, Strom et al. have shown that withholding sedation in critically ill patients on mechanical ventilation is associated with an increase in days without ventilation. [22] This move has been made possible by the improvement in ventilator algorithms, which are increasingly flexible in dealing with variable patient efforts. [23] Now, we have progressed from deep sedation for days on end to those that involve keeping patients in the ICU much more awake and interactive.

Another method of improving the neurologic and functional outcome of mechanically ventilated patients is the use of the "ABCDE" bundle, i.e Awake and Breathing co-ordination, Choice of sedatives and analgesics, Delirium monitoring, Early mobility and exercise where spontaneous awakening and breathing trials have been combined is found to be very promising. [24]

   Awareness Among the Young Doctors and Nursing Staff Top

Many of the young doctors, including recently qualified anaesthesiolgists, may not be aware of many of the sedation scoring systems used and many of the ICUs may not have a protocol for sedation. Hence, sedation protocols should be standardized in every critical care unit, and every health care person working in the ICU should be made aware of the protocol used. A simple scoring system like NICS can be used, which can be easily followed by the nursing staff and duty doctors in the ICU. At this juncture, a national survey regarding the sedation practice in the majority of the ICUs in India is required.

   References Top

1.Devlin JW. The pharmacology of oversedation in mechanically ventilated adults. Curr Opin Crit Care 2008;14:403-7.  Back to cited text no. 1
2.Tonner PH, Paris A, Scholz J. Monitoring consciousness in intensive care medicine. Best Pract Res Clin Anaesthesiol 2006;20:191-200.  Back to cited text no. 2
3.Burns AM, Shelly MP, Park GR. The use of sedative agents in critically ill patients. Drugs 1992;43;507-75.  Back to cited text no. 3
4.Ouimet S, Kavanagh BP, Gottfried SB, Skrobik Y. Incidence, risk factors and consequences of ICU delirium. Intensive Care Med 2007;33:66-73.  Back to cited text no. 4
5.Fuchs EM, Rueden KV. Sedation Management in the Mechanically Ventilated Critically Ill Patient. AACN Adv Crit Care 2008;19:421-32.  Back to cited text no. 5
6.Mirski MA, LeDroux SN, Lewin JJ 3 rd , Thompson CB, Mirski KT, Griswold M. Validity and reliability of an intuitive conscious sedation scoring tool: The nursing instrument for the communication of sedation. Crit Care Med 2010;38:1674-84.  Back to cited text no. 6
7.Arbour R, Waterhouse J, Seckel MA, Bucher L. Correlation between the sedation-agitation scale and the bispectral index in ventilated patients in the intensive care unit. Heart Lung 2009;38:336-45.  Back to cited text no. 7
8.Dahaba AA, Lischnig U, Kronthaler R, Bornemann H, Georgiev V, Rehak PH, et al. Bispectral-index guided versus clinically guided remifentanil/propofol analgesia/ sedation for interventional radiological procedures: an observer-blinded randomized study. Anesth Analg 2006;103:378-84.  Back to cited text no. 8
9.Vivien B, Di Maria S, Ouattara A, Langeron O, Coriat P, Riou B. Overestimation of bispectral index in sedated intensive care patients revealed by administration of muscle relaxant. Anesthesiology 2003;99:9-17.  Back to cited text no. 9
10.Deogaonkar A, Gupta R, De Georgia M, Sabharwal V, Gopakumaran B, Schubert A, et al. Bispectral index monitoring correlates with sedation scales in brain-injured patients. Crit Care Med 2004;32:2403-6.  Back to cited text no. 10
11.Consales G, Chelazzi C, Rinaldi S, De Gandio AR. Bispectral index compared to Ramsay score for sedation monitoring in intensive care units. Minerva Anestesiol 2006;72:329-36.  Back to cited text no. 11
12.Arbour R. Impact of bispectral index monitoring on sedation and outcomes in critically ill adults: a case series. Crit Care Nurs Clin N Am 2006;18:227-41.  Back to cited text no. 12
13.Johansen JW. Update on bispectral index monitoring. Best Pract Res Clin Anaesthesiol 2006;20:81-99.  Back to cited text no. 13
14.Tonner PH, Wei C, Bein B, Weiler N, Paris A, Scholz J. Comparison of two bispectral index algorithms in monitoring sedation in postoperative intensive care patients. Crit Care Med 2005;33:580-4.  Back to cited text no. 14
15.Gélinas C, Tousignant-Laflamme Y, Tanguay A, Bourgault P. Exploring the validity of the bispectral index, the critical-care pain observation tool and vital signs for the detection of pain in sedated and mechanically ventilated critically ill adults: A pilot study. Intensive Crit Care Nurs 2011;27:46-52.  Back to cited text no. 15
16.Kress JP, Pohlman AS, O'Connor MF, Hall JB. Daily Interruption of Sedative Infusions in Critically Ill Patients Undergoing Mechanical Ventilation. N Engl J Med 2000;342:1471-7.  Back to cited text no. 16
17.Heffner JE. A wake-up call in the intensive care unit. N Engl J Med 2000;342:1520-2.  Back to cited text no. 17
18.Jackson JC, Girard TD, Gordon SM, Thompson JL, Shintani AK, Thomason JW, et al. Long-term cognitive and psychological outcomes in the awakening and breathing controlled trial. Am J Respir Crit Care Med 2010;182:183-91.  Back to cited text no. 18
19.Kress JP, Gehlbach B, Lacy M, Pliskin N, Pohlman AS, Hall JB. The long-term psychological effects of daily sedative interruption on critically ill patients. Am J Respir Crit Care Med 2003;168:1457-61.  Back to cited text no. 19
20.Jones C, Griffiths RD, Humphris G, Skirrow PM. Memory, delusions and the development of acute posttraumatic stress disorder-related symptoms after intensive care. Crit Care Med 2001;29:573-80.  Back to cited text no. 20
21.Girard TD, Shintani AK, Jackson JC, Gordon SM, Pun BT, Henderson MS, et al. Risk factors for posttraumatic stress disorder symptoms following critical illness requiring mechanical ventilation: A prospective cohort study. Crit Care 2007;11:R28.  Back to cited text no. 21
22.Strøm T, Martinussen T, Toft P. A protocol of no sedation for critically ill patients receiving mechanical ventilation: A randomised trial. Lancet 2010;375:475-80.  Back to cited text no. 22
23.Bracco D, Donatelli F. Volatile agents for ICU sedation? Intensive Care Med 2011;37:895-7.  Back to cited text no. 23
24.Morandi A, Brummel NE, Ely EW. Sedation, delirium and mechanical ventilation: The 'ABCDE' approach, Curr Opin Crit Care 2011;17:43-9.  Back to cited text no. 24


  [Table 1]

This article has been cited by
1 Sedation and its psychological effects following intensive care
Clare Croxall,Moira Tyas,Joanne Garside
British Journal of Nursing. 2014; 23(14): 800
[Pubmed] | [DOI]


    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
    Access Statistics
    Email Alert *
    Add to My List *
* Registration required (free)  

  In this article
    Daily Interrupti...
    Awareness Among ...
    Article Tables

 Article Access Statistics
    PDF Downloaded10634    
    Comments [Add]    
    Cited by others 1    

Recommend this journal