We have identified efforts by research ers to investigate interventions which seek to improve information delivery and consideration of information to enhance  informed consent .
The interventions used consistently improve patient knowledge , an important prerequisite for informed consent .
This is encouraging and these measures could be widely employed although we are not able to say with confidence which types of interventions are preferable .
Our results should be interpreted with caution due to the high levels of heterogeneity associated with many of the main analyses although we believe there is broad evidence of beneficial outcomes for patients with the pragmatic application of interventions .
BACKGROUND Achieving informed consent is a core clinical procedure and is required before any surgical or invasive procedure is undertaken .
However , it is a complex process which requires patients be provided with information which they can underst and and retain , opportunity to consider their options , and to be able to express their opinions and ask questions .
There is evidence that at present some patients undergo procedures without informed consent being achieved .
OBJECTIVES To assess the effects on patients , clinicians and the healthcare system of interventions to promote informed consent for patients undergoing surgical and other invasive healthcare treatments and procedures .
AUTHORS ' CONCLUSIONS Informed consent is an important ethical and practical part of patient care .
Effects of video information on precolonoscopy anxiety and knowledge: a randomised trial
BACKGROUND The provision of information before medical or surgical procedures should improve knowledge and allay anxiety about the pending procedure . This trial aim ed to assess the value of an information video in this process . METHODS Patients scheduled to undergo colonoscopy were approached about 1 week before the procedure . All patients were given an information leaflet about colonoscopy , and completed a  Spielberger state anxiety inventory ( STAI ) question naire to assess baseline anxiety . The patients were then r and omly assigned to watch or not watch the information video . Immediately before colonoscopy , all patients completed a second anxiety question naire and a knowledge question naire . FINDINGS 198 patients were screened . 31 declined to participate and 17 were unable to complete the forms . Of the remaining 150 patients , 72 were assigned the video , and 78 no video . The groups were similar with regard to age , sex , educational attainment , and initial anxiety score . Female patients had higher baseline anxiety than male patients ( mean STAI 46.3 [ 95 % CI 44.9 - 47.7 ] vs 36.9 [ 35.5 - 38.3 ] ; difference 9.4 [ 7.8 - 12.2 ] , p=0.0008 ) . Patients who had not had a previous colonoscopy had higher baseline anxiety scores than those who had prior experience of the procedure ( 46.9 [ 45.4 - 48.5 ] vs 36.3 [ 34.7 - 37.9 ] ; difference 10.6 [ 7.5 - 13.8 ] , p=0.0008 ) . Patients who watched the video were significantly less anxious before colonoscopy than those who did not . The former also scored more highly in the knowledge question naire than the latter with regard to the purpose of the procedure , procedural details , and potential complications of colonoscopy . INTERPRETATION An information video increases knowledge and decreases anxiety in patients preparing for colonoscopy
We have identified efforts by research ers to investigate interventions which seek to improve information delivery and consideration of information to enhance  informed consent .
The interventions used consistently improve patient knowledge , an important prerequisite for informed consent .
This is encouraging and these measures could be widely employed although we are not able to say with confidence which types of interventions are preferable .
Our results should be interpreted with caution due to the high levels of heterogeneity associated with many of the main analyses although we believe there is broad evidence of beneficial outcomes for patients with the pragmatic application of interventions .
BACKGROUND Achieving informed consent is a core clinical procedure and is required before any surgical or invasive procedure is undertaken .
However , it is a complex process which requires patients be provided with information which they can underst and and retain , opportunity to consider their options , and to be able to express their opinions and ask questions .
There is evidence that at present some patients undergo procedures without informed consent being achieved .
OBJECTIVES To assess the effects on patients , clinicians and the healthcare system of interventions to promote informed consent for patients undergoing surgical and other invasive healthcare treatments and procedures .
AUTHORS ' CONCLUSIONS Informed consent is an important ethical and practical part of patient care .