Question 1

Last updated 30/04/2017 - 17:53
 Topic: Miscellaneous Topics
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Critically evaluate the role of a daily interruption of sedation for mechanically ventilated patients in the ICU.

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College Answer

Introduction / Rationale

A daily interruption of sedation is a strategy designed to reduce exposure to sedative agents, allow assessment of neurological status and assess readiness for extubation and to reduce duration of mechanical ventilation.

Evidence

Initial trials showed a marked reduction in duration of mechanical ventilation, and decreased duration of intensive care length of stay (e.g. Kress et al, NEJM 2000). It was notable that no sedation target nor protocol was used in the control group, thus this group may have been oversedated, analogous to the 12ml/kg TV group in the ARDSNET low TV trial.

Subsequent studies have been somewhat conflicting:

  • ABC study (Girard et al, Lancet 2008) showed improved outcomes (mortality, less time on mechanical ventilation, reduced ICU length of stay) in patients treated with a paired daily interruption of sedation and a spontaneous breathing trial compared to usual care plus a spontaneous breathing trial.
  • SLEAP study (Mehta et al JAMA, 2012) showed no difference in outcomes comparing protocolised sedation to protocolised sedation plus daily interruption of sedation.

Disadvantages / Adverse effects / Limitations

Potential adverse effects of daily interruption of sedation:

  • Patient discomfort and risk of PTSD and other long term psychological issues
  • Dislodgment of ETT, CVC, arterial lines etc.
  • Increased nursing workload.
  • Cessation of sedation could lead to agitation which can be associated with physiological instability, hypertension, tachycardia, ventilator dysynchrony and hypoxaemia, which could be associated with exacerbation of primary disease in certain conditions, e.g. myocardial ischaemia, brain injury.
  • I.e. interruption of sedation contra-indicated in above patient groups.

Own Practice

Any reasonable justifiable approach acceptable.

Summary

Daily interruption of sedation may have a role in physiologically stable patients in ICUs that do not routinely use protocolised sedation.

Discussion

Rationale

  • Exposure to sedating agents is undesirable, given that most agents have unpleasant side-effects
  • Interruptions in sedation may decrease the total dose of sedation over the course of one's ICU stay

Proposed advantages

  • More rapid weaning from ventilation
  • Reduction in ICU length of stay
  • Reduced need for vasopressors
  • Reduced need for fluid boluses

Expected disadvantages

  • Greater risk of self-extubation
  • Greater psychological distress; potential for PTSD
  • Increased nursing workload
  • Increased patient-ventilator dyssynchrony

Evidence:

  • Kress et al (2000) - small single centre RCT; n=128
    • length of stay in ICU and duration of ventilation was reduced
  • Kress et al (2003) - small single centre RCT; n=108
    • reduced symptoms of PTSD; no adverse psychological outcome
  • Girard et al (2008) - multicentre trial, n=336
    • Reduced mortality at 1 year, but increased risk of self-extubation
  • Mehta et al (2012) - multicentre randomised controlled trial, n=430
    • No reduction in length of ICU stay or duration of ventilation
  • Cochrane verdict (2014) - meta-analysis, n=1282; no strong evidence in support of this practice. Tracheostomy may be performed less often.

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