Systematic reviews were undertaken to attempt to answer the questions specific to critical bleeding or massive transfusion, and the generic questions relevant to all six modules. The systematic review questions are listed in Box 2.1.
To answer these questions, comprehensive search strategies were designed, as detailed in Volume 2 of the technical report.3 Searches were conducted in relevant electronic databases, bibliographies of studies identified as relevant, and literature recommended by expert members of the CRG.
The systematic review included only data from studies that met the relevant inclusion criteria, were of adequate quality and were published before July 2009.2 Identification of relevant evidence and assessment of evidence was conducted in accordance with NHMRC standards and procedures for externally developed guidelines.9
Box 2.1 Systematic review questions
Questions 1 and 2 are specific to critical bleeding or massive transfusion (i.e. to this module); questions 3–8 are relevant to all six modules of these guidelines.
- Question 1 – In patients with critical bleeding requiring massive transfusion, what is
the effect of variation of physiologic, biochemical and metabolic (including temperature)
parameters on morbidity, mortality and transfusion rate?
(Prognostic question) - Question 2 – In patients with critical bleeding requiring massive transfusion, does the
dose, timing and ratio (algorithm) of RBCs to blood component therapy (FFP, platelets, cryoprecipitate or fibrinogen concentrate) influence morbidity, mortality and transfusion rate?
(Interventional question) - Question 3 – In patients with critical bleeding requiring massive transfusion, is anaemia
an independent risk factor for adverse outcomes?
(Aetiological question) - Question 4 – In patients with critical bleeding requiring massive transfusion, what is the
effect of RBC transfusion on patient outcomes?
(Interventional question) - Question 5 – In patients with critical bleeding requiring massive transfusion, what is
the effect of non-transfusion interventions to increase haemoglobin concentration on
morbidity, mortality and need for RBC blood transfusion?
(Interventional question) - Question 6 – In patients with critical bleeding requiring massive transfusion, what is the
effect of rFVIIa (prophylaxis or treatment) on morbidity, mortality and transfusion rate?
(Interventional question) - Question 7 – In patients with critical bleeding requiring massive transfusion, what is the
effect of FFP, cryoprecipitate, fibrinogen concentrate, and/or platelet transfusion on patient outcomes?
(Interventional question) - Question 8 – In patients with critical bleeding requiring massive transfusion, what INR
(PT/APTT) for FFP, fibrinogen level for cryoprecipitate and platelet count for platelets concentrates should patients be transfused to avoid risks of significant adverse events?
(Prognostic question)
APTT, activated partial thromboplastin time; FFP, fresh frozen plasma; INR, international normalised ratio; PT, prothrombin time; RBC, red blood cell; rFVIIa, recombinant activated factor VII