Capillary refill time (CRT) is widely used by health care workers as part of the rapid, structured cardiopulmonary assessment of critically ill patients. Measurement involves the visual inspection of blood returning to distal capillaries after they have been emptied by pressure. It is hypothesized that CRT is a simple measure of alterations in peripheral perfusion. Evidence for the use of CRT in anesthesia is lacking and further research is required, but understanding may be gained from evidence in other fields. In this report, we examine this evidence and factors affecting CRT measurement. Novel approaches to the assessment of CRT are under investigation. In the future, CRT measurement may be achieved using new technologies such as digital videography or modified oxygen saturation probes; these new methods would remove the limitations associated with clinical CRT measurement and may even be able to provide an automated CRT measurement.

Undergoing general anaesthesia is distressing for children, with up to two-thirds demonstrating abnormal behaviours after their procedure, such as emergence delirium (ED) and post-hospitalization behaviour change. The aim of this systematic review was to determine the effect of intraoperative i.v. α₂-adrenergic agonists on postoperative behaviour in children. We included published full-text reports of randomized controlled trials involving children who received i.v. clonidine or dexmedetomidine after induction of general anaesthesia, who were assessed for postoperative behavioural disturbance. After screening of references identified by the search strategy, a data collection form was developed and piloted. Data extraction was performed by one reviewer and checked by a second. Twelve randomized trials met the inclusion criteria. Ten studies (n=669) reported dichotomous data that were included in the pooled analysis of α₂-adrenergic agonists vs placebo. There was strong evidence that i.v. α₂-adrenergic agonists reduced postoperative ED (overall summary odds ratio 0.28, 95% confidence interval 0.19-0.40, P<0.001). No studies examined post-hospitalization negative behaviour changes. There was evidence that α₂-adrenergic agonists prolonged time in the recovery room. No adverse haemodynamic events were reported in any arm of any study. This meta-analysis provides evidence that intraoperative i.v. α₂-adrenergic agonists reduce the incidence of emergency delirium in children. The prolongation of time in recovery is unlikely to be clinically relevant. The absence of data regarding the effect on post-hospitalization behavioural changes provides an opportunity for future research.

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