Optimizing cerebral perfusion pressure during fiberoptic bronchoscopy in severe head injury: effect of hyperventilation

Multimodality monitoring consensus statement: monitoring in emerging economies

The burden of disease and so the need for care is often greater at hospitals in emerging economies. This is compounded by frequent restrictions in the delivery of good quality clinical care due to resource limitations. However, there is substantial heterogeneity in this economically defined group, such that advanced brain monitoring is routinely practiced at certain centers that have an interest in neurocritical care. It also must be recognized that significant heterogeneity in the delivery of neurocritical care exists even within individual high-income countries (HICs), determined by costs and level of interest. Direct comparisons of data between HICs and the group of low- and middle-income countries (LAMICs) are made difficult by differences in patient demographics, selection for ICU admission, therapies administered, and outcome assessment. Evidence suggests that potential benefits of multimodality monitoring depend on an appropriate environment and clinical expertise. There is no evidence to suggest that patients in LAMICs where such resources exist should be treated any differently to patients from HICs. The potential for outcome benefits in LAMICs is arguably greater in absolute terms because of the large burden of disease; however, the relative cost/benefit ratio of such monitoring in this setting must be viewed in context of the overall priorities in delivering health care at individual institutions.

Hyperventilation therapy for acute traumatic brain injury

BACKGROUND

Because hyperventilation is often associated with a rapid fall in intracranial pressure, it has been assumed to be effective in the treatment of severe head injury. Hyperventilation reduces raised intracranial pressure by causing cerebral vasoconstriction and a reduction in cerebral blood flow. Whether reduced cerebral blood flow improves neurological outcome however, is unclear.

OBJECTIVES

To quantify the effect of hyperventilation on death and neurological disability following head injury.

SEARCH STRATEGY

The search strategy drew on that of the Injuries Group as a whole. The reference lists of all relevant articles identified were checked and the first author of reports was contacted to ask for assistance in identifying any further trials. Most recent search was done in September 1999.

SELECTION CRITERIA

All randomised trials of hyperventilation, in which study participants had a clinically defined acute traumatic head injury of any severity. There were no language restrictions.

DATA COLLECTION AND ANALYSIS

We collected data on the participants, the timing and duration of the intervention, duration of follow up, neurological disability and death. Relative risks (RR) and 95% confidence intervals were calculated for each trial on an intention to treat basis. Timing, degree and duration of hyperventilation were identified a-priori as potential sources of heterogeneity between trials.

MAIN RESULTS

One trial of 113 participants was identified. Hyperventilation alone, as well as in conjunction with the buffer THAM showed a beneficial effect on mortality at one year after injury, although the effect measure was imprecise (RR=0.73; 95% CI 0.36;1.49 and RR=0.89; 95% CI 0.47;1.72 respectively). This improvement in outcome was not supported by an improvement in neurological recovery. For hyperventilation alone, the RR for death or severe disability was 1. 14 (95% CI 0.82;1.58). The RR for death or severe disability in the hyperventilation plus THAM group, was 0.87 (95% CI 0.58;1.28).

REVIEWER'S CONCLUSIONS

The data available are inadequate to assess any potential benefit or harm that might result from hyperventilation in severe head injury. Randomised controlled trials to assess the effectiveness of hyperventilation therapy following severe head injury are needed.