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Sedation in haemofiltered patients: a retrospective study of compliance with the sedation policy


This study was designed to review sedation of critically ill patients requiring haemofiltration and to assess the compliance with our sedation policy.


Such patients are of particular concern as there is a danger of accumulation of sedatives. The UCLH sedation scale involves hourly assessment, -3 correlates with unrousable, -2 (roused by painful stimuli), -1 (roused by movement), 0 (roused by voice), 1 (aware but calm), 2 (aware and comfortable), 3 (agitated and restless). The sedation policy requires the following interventions: at +3 or +2 the dose is increased; at +1, 0 or -1 (i.e. the 'target range') no dose adjustment is attempted until three consecutive scores are achieved within the target range when dose reduction is attempted; at -2 or -3, sedation is stopped.


This retrospective study was conducted in a 22-bed, mixed medical/surgical ICU in a teaching hospital. A total of 427 patients received haemofiltration between 10 September 2003 and 18 January 2004 for a total of 56,024 hours. The data for these patients who were managed with continuous sedation infusions were extracted using the UCLH Clinical Information Management System (GE Medical-healthcare QS 5.6). The level of compliance to our sedation policy was analysed by comparison with the aforementioned rules. A chi-squared test was used for statistical significance.


In 42% of oversedation hours (-2, -3) the sedative infusion was not reduced (see Fig. 1). Where sedation scores fell within the target range on three consecutive occasions sedation infusions were decreased or stopped appropriately in 78% of episodes. In undersedated hours (+2, +3), sedation infusions were increased in 29% of episodes. Sedation scores within the target range were achieved for 77.7% of the time, regardless of whether or not sedatives were given. Furthermore, sedation scores shared a similar distribution pattern in both sedated and unsedated hours except that the +1 sedation score was more prevalent in unsedated hours compared with sedated hours (1818 hours [10.9%] vs 15,451 hours [39.2%]). Episodes of undersedation were three times (3151 hours vs 1312 hours) more likely to be treated incorrectly than correctly (P < 0.05). In oversedated episodes, correct adjustment occurred > 3 times more often than incorrect changes (27,810 hours vs 7900 hours) (P < 0.05).

Figure 1

Percentage of appropriate adjusments in sedation infusions.


Our data suggest that when patients were undersedated a reluctance to follow the sedation protocol by increasing the sedative dose was seen. In contrast, when patients were oversedated nurses were more inclined to follow the protocol.

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Al-Saffar, S., Shulman, R. & Webb, A. Sedation in haemofiltered patients: a retrospective study of compliance with the sedation policy. Crit Care 9, P140 (2005).

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  • Target Range
  • Sedation Infusion
  • Sedation Policy
  • Information Management System
  • Sedation Score