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 .
Effect of informed consent for intravascular contrast material on the level of anxiety: how much information should be given?
Purpose : To compare the effect of two different informed consent forms on patients ' anxiety level prior to intravenous contrast material ( IVCM ) injection . Material and Methods : Two different informed consent forms were r and omly given to 265 consecutive patients referred for either intravenous pyelography or computed tomography requiring IVCM injections . Form 1 had brief information , including only the common risks and risk factors associated with IVCM , while Form 2 had more comprehensive information . Before being presented with the two different informed consent forms , 191 of the 265 patients filled out two other forms evaluating : 1 : How they felt in that particular situation/moment ( STAI-T ) ; and 2 : How they felt independently of the situation or condition at that moment ( STAI-S ) . After the patients were informed , the STAI-T ( measuring how they felt in that particular situation ) was filled out once more to see if the anxiety level had changed . Results : The anxiety level for 88 patients receiving Form 1 decreased after they were given the informed consent ( P = 0.033 ) . However , among the 103 patients receiving Form 2 , the anxiety level showed a significant increase ( P = 0.001 ) compared to the values obtained before Form 2 was given . Conclusion : These results indicate that informed consent , including brief information about the risk factors and potential adverse reactions of IVCM , reduces anxiety level , while detailed information before the procedure increases the anxiety level
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 .