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 .
Factors affecting quality of informed consent.
OBJECTIVE --To examine the factors influencing quality of informed consent .  DESIGN -- Prospect i ve study comprising interviews with patients and patients ' completing st and ard question naires . SETTING --Academic surgical unit of large teaching hospital . PATIENTS --265 patients undergoing intrathoracic , intraperitoneal , and vascular surgical procedures .  Of these patients , 192 have been followed up for six months . MAIN OUTCOME MEASURES -- Patients ' recall of information at various points in the study ; this score was compared by age , provision of written information , cognitive function , intelligence quotient ( IQ ) , mood state and personality traits , and health locus of control . RESULTS --The patients were best informed immediately after signing the consent form and from then on recall of information deteriorated . A total of 172/250 ( 69 % ) patients admitted to not reading the consent form before signing it . Old age adversely affected recall of information at all assessment points . Impaired cognitive function reduced information recall only during the stay in hospital . Patients with above average IQs h and led information better than those with a lower IQ except immediately after the signing of consent forms . Patients with an internal locus of health control ( that is , those who believed their health to be in their own control ) were better informed than those with an external locus of health control . Operation information cards improved recall only on the day of discharge . CONCLUSION --Elderly patients and patients with below average IQ , impaired cognitive functions , and an external locus of control have poor information recall . Written information may be more useful if given before admission to hospital
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 .