Advanced life support versus basic life support in the pre-hospital setting: a meta-analysis.

BACKGROUND: The scientific evidence of a beneficial effect of ALS in pre-hospital treatment in trauma patients or patients with any acute illness is scarce. The objective of this systematic review of controlled studies was to examine whether ALS, as opposed to BLS, increases patient survival in pre-hospital treatment and if so, to identify the patient groups that gain benefit. METHODS: A systematic review of studies published in the databases Medline (PubMed), EMBASE, Cochrane Library and Scopus up to July 31st, 2010. Controlled studies comparing survival after the pre-hospital ALS treatment versus BLS treatment in trauma patients or patients with cardiac arrest were included. RESULTS: We identified 1081 studies of which 18 met our inclusion criteria. In nine of 18 studies including 16,857 trauma patients in the intervention group, ALS care did not increase survival compared to BLS treatment (pooled OR 0.892, 95% CI, 0.775-1.026). In nine of 18 studies including 7659 patients with cardiac arrest in the intervention group, ALS care increased survival compared to BLS treatment (OR 1.468, 95% CI, 1.257-1.715). Most subgroup analyses revealed no significant interactions, but data from six trials, where ALS was provided by physicians, increases the probability of survival at hospital discharge even more (OR 2.047, 95% CI 1.593-2.631). CONCLUSION: Implementation of ALS care to non-traumatic cardiac arrest patients can increase survival and further research is unlikely to change our confidence in the estimate of the effect. On the contrary, in trauma patients our meta-analysis revealed that ALS care is not associated with increased survival. However, only few controlled studies of sufficient quality and strength examining survival with pre-hospital ALS treatment exist.

Role of the classical pathway of complement activation in experimentally induced polymicrobial peritonitis.

The complement system and the natural antibody repertoire provide a critical first-line defense against infection. The binding of natural antibodies to microbial surfaces opsonizes invading microorganisms and activates complement via the classical pathway. Both defense systems cooperate within the innate immune response. We studied the role of the complement system in the host defense against experimental polymicrobial peritonitis using mice lacking either C1q or factor B and C2. The C1q-deficient mice lacked the classical pathway of complement activation. The factor B- and C2-deficient mice were known to lack the classical and alternative pathways, and we demonstrate here that these mice also lacked the lectin pathway of complement activation. Using inoculum doses adjusted to cause 42% mortality in the wild-type strain, none of the mice deficient in the three activation routes of complement (factor B and C2 deficient) survived (mortality of 100%). Mortality in mice deficient only in the classical pathway of complement activation (C1q deficient) was 83%. Application of further dilutions of the polymicrobial inoculum showed a dose-dependent decrease of mortality in wild-type controls, whereas no changes in mortality were observed in the two gene-targeted strains. These results demonstrate that the classical activation pathway is required for an effective antimicrobial immune defense in polymicrobial peritonitis and that, in the infection model used, the remaining antibody-independent complement activation routes (alternative and lectin pathways) provide a supporting line of defense to gain residual protection in classical pathway deficiency.