Qualitative methods in a randomised controlled trial: the role of an integrated qualitative process evaluation in providing evidence to discontinue the intervention in one arm of a trial of a decision support tool.

OBJECTIVE: To understand participants' experiences and understandings of the interventions in the trial of a computerised decision support tool in patients with atrial fibrillation being considered for anti-coagulation treatment. DESIGN: Qualitative process evaluation carried out alongside the trial: non-participant observation and semistructured interviews. PARTICIPANTS: 30 participants aged >60 years taking part in the trial of a computerised decision support tool. RESULTS: Qualitative evidence provided the rationale to undertake a decision to discontinue one arm of the trial on the basis that the intervention in that arm, a standard gamble values elicitation exercise was causing confusion and was unlikely to produce valid data on participant values. CONCLUSIONS: Qualitative methods used alongside a trial allow an understanding of the process and progress of a trial, and provide evidence to intervene in the trial if necessary, including evidence for the rationale to discontinue an intervention arm of the trial.

Which paediatric head injured patients might benefit from decompression? Thresholds of ICP and CPP in the first six hours.

Severe head injury in childhood continues to be associated with considerable mortality and morbidity. Early surgical decompression may be beneficial and the objective of this study was to examine the relationship between age-related thresholds of mean intracranial pressure (ICP) and cerebral perfusion pressure (CPP) over the first 6 hours and age outcome in paediatric head injury patients. A total of 209 head injured children admitted to five UK hospitals were studied. Patients aged 2 to 16 years were included if they had a minimum of six hours of invasive pressure monitoring. Mean values of ICP and CPP over this period were calculated and compared to those with independent (good recovery and moderate disability) and poor outcome (severe disability, and death) for different age groups. There were 148 children with independent outcome (92 good recovery, 56 moderately disabled), and 61 with poor outcome (30 severely disabled, 31 deaths). There was a significant difference between those with independent compared to poor outcome in relation to ICP (p < 0.001) and CPP (p < 0.001). Patients were divided into three groups according to age. The sensitivity of ICP and CPP in predicting outcome was similar for all groups but the specificity differed between groups. At a CPP of 50 mmHg the specificity varied between the age groups (2 to 6 years: 0.47, 7 to 10 years: 0.28 and 11 to 16 years: 0.10) and similarly for an ICP of 25 mmHg (2 to 6 years: 0.53, 7 to 10 years: 0.44 and 11 to 16 years: 0.38). Younger children may be able to tolerate lower perfusion pressures and still have an independent outcome. Our threshold values for young children are likely to be important in the identification of patients who might benefit from new treatments such as surgical decompression.

Age-related differences in intracranial pressure and cerebral perfusion pressure in the first 6 hours of monitoring after children's head injury: association with outcome.

OBJECTIVES: Severe head injury in childhood is associated with considerable mortality and morbidity. In this study we determined age-related differences in the relationship between outcome and intracranial pressure (ICP) and cerebral perfusion pressure (CPP) in the first 6 h of monitoring in a large cohort of head-injured children. METHODS: Two hundred and thirty-five head-injured children (admitted to five UK hospitals over a 15-year period) in whom intracranial pressure monitoring was clinically indicated were studied. RESULTS: Patients were divided into three age groups (2-6, 7-10 and 11-16 years). The sensitivity of ICP and CPP were similar. Differences were found in the specificity of ICP and CPP for each group and these were more marked for CPP. For a specificity of 50% the pressures were 53, 63 and 66 mmHg for the three age groups. CONCLUSIONS: There are age-related differences in the specificity of intracranial pressure and cerebral perfusion pressure in relation to outcome. These differences may be important in the clinical management of head-injured children. Thus cerebral perfusion pressures of 53, 63 and 66 mmHg should be the minimum to strive for in these three age groups respectively.

Elderly patients with severe head injury in coma from the outset--has anything changed?

Advancing age is known to be a determinant of outcome in head injury. We have sought to discover whether there has been any change in the outcome of elderly patients with severe head injury in Newcastle, where these patients have continued to be treated with maximum intervention. A review of prospectively collected data from the Newcastle Head Injury Database for the period 1990 to 2000 was carried out. All patients aged 70 years and above who had sustained a severe head injury (Glasgow Coma Score of 8 or less from the outset) were included. The Glasgow Outcome Score (GOS) was determined at 6 months. Seventy-one patients were identified. Fifty-seven (80%) died and 2 (3%) were in a vegetative state, 11 (16%) had severe disability, 1 (1%) had moderate disability and no patients made a good recovery. The natural history of this condition remains unchanged and due consideration should be given to this when evaluating interventions for elderly patients with a severe head injury.