Evid Based Nurs 11:124 doi:10.1136/ebn.11.4.124
  • Quality improvement

Protocol-directed sedation did not reduce duration of mechanical ventilation or hospital stay in ICU patients

T K Bucknall

Dr T K Bucknall, Deakin University, Burwood, Victoria, Australia; tracey.bucknall{at}


Does protocol-directed sedation reduce duration of mechanical ventilation in intensive care units (ICUs)?



randomised controlled trial.




blinded {data collectors, outcome assessors, and data analysts}.*

Follow-up period:

duration of hospital stay.


a 24-bed, university-affiliated, mixed medical-surgical-trauma ICU in Australia.


316 adults who were mechanically ventilated. Patients admitted after cardiac surgery or who were previously enrolled in the study were excluded.


155 patients were allocated to the sedation protocol, which specified medications to be prescribed to achieve a Sedation Agitation Scale (SAS) target. Nurses determined sedation and analgesia type, dose, and method of administration to provide optimal care consistent with the protocol. 161 patients were allocated to usual sedation practice, which included physician-selected prescription of sedation medication, and assessment, titration, and management of sedation by ICU nurses within prescribed limits.


duration of mechanical ventilation (from start to successful weaning). Secondary outcomes included ICU and hospital lengths of stay and mortality.

Patient follow-up:

99% (mean age 57 y, 61% men).


The sedation protocol and usual care groups did not differ for duration of mechanical ventilation (median 79 v 58 h, adjusted hazard ratio 0.78, 95% CI 0.60 to 1.02), ICU or hospital mortality (table), or median lengths of stay in the ICU (94 v 88 h, p = 0.58) or hospital (13 v 13 d, p = 0.97).

Protocol-directed v usual sedation care for mechanically ventilated patients*


Protocol-directed sedation did not reduce duration of mechanical ventilation, length of hospital stay, or mortality in patients on mechanical ventilation in intensive care.

*Information provided by author.


Bucknall TK, Manias E, Presneill JJ. A randomized trial of protocol-directed sedation management for mechanical ventilation in an Australian intensive care unit. Crit Care Med 2008;36:1444–50.

Clinical impact ratings: Critical care 6/7; Respirology 4/7


  • Source of funding: in part, Abbott Australasia Pty Ltd and Australian College of Critical Care Nurses.


Few studies examining use of sedation protocols in the ICU have considered the experience and skill mix of the staff using these tools. The study by Bucknall et al tests the replicability of the findings of a US study of a sedation protocol1 in an Australian context. In contrast to the earlier study,1 Bucknall et al found no evidence that sedation protocols improved weaning time or patient outcomes. The authors hypothesised that one reason for this discrepancy could be differences between the 2 countries in ICU staffing and nursing practice. However, the staffing and skill mixes reported in the study by Bucknall et al were described with little more detail than that provided by Brook et al.1 Therefore, it is not possible to establish if staffing differences can explain differences in the results or if study findings are relevant to other hospitals.

Although the sedation protocol used by Bucknall et al was derived from the study that was being replicated,1 minor differences in protocols between the 2 studies could have accounted for different results. Nurses in the usual care group were not given a specific study protocol but could have used the principles of one from previous experience. As the authors note, inability to blind staff in this type of study can also lead to bias. For example, performance bias by nurses could have influenced weaning decisions and affected the primary outcome.

The results of the study by Bucknall et al give rise to more questions than answers. The issue of skill mix and capability should certainly be considered in future studies. In the meantime, there is no reason to change current practice on use of sedation protocols in the ICU. Clinically, any practice that encourages appropriate use of sedation and regular evaluation for readiness to wean should continue.


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