Supplemental Digital Content 1: Risk of Bias
Supplemental Digital Content 1: Risk of bias.
Studies were assessed for methodological quality using the Cochrane Collaboration’s tool for assessing risk of bias.
Risk of bias and study quality
The risk of bias for adequate sequence generation was judged to be low for 18 trials, inadequate for 2 trials and the remaining 27 trials presented no information and were rated unclear. Allocation concealment was judged to be low in 17 trials, inadequate for 2 trials and the remaining 28 trials were rated unclear. Blinding of participants and personnel as well as blinding of outcome assessment could be assured in 2 trials, 7 trials were rated as inadequate and the remaining 38 trials as unclear. Six trials were graded with low risk in respect of attrition bias, 10 trials as inadequate and 31 trials as unclear. None of the studies provided data for reporting bias or other bias (Supplemental Digital Content 5 and 6).
Funnel plot analysis of all types of surgery and showed no obvious deviations from symmetry excluding the possibility of potential publication bias (data not shown).
Supplemental Digital Content 2: Methodological quality of graph.
Each methodological quality item is presented as percentages across all studies based on review authors’ judgements
Supplemental Digital Content 3: Methodological quality summary. Each methodological quality item is presented for each included study
Supplemental Digital Content 4: Forest plot of cell salvage compared to no cell salvage in all types of surgery.
A) Number of patients exposed to re-operation, B) to plasma, C) to platelets, D) myocardial infarction, E) stroke, F) length of hospital stay.
Supplemental Digital Content 5: Forest plot of cell salvage compared to no cell salvage in multiple trauma/massive transfusion.
A) Number of patients exposed to allogeneic RBC, B) Number of units of allogeneic RBC per patient, C) infections, D) mortality rate.
Supplemental Digital Content 6: Forest plot of cell salvage compared to no cell salvage in cancer surgery.
A) Number of patients exposed to allogeneic RBC, B) Number of units of allogeneic RBC per patients.
Supplemental Digital Content 7: Forest plot of cell salvage compared to no cell salvage in pediatric surgery.
A) Number of patients exposed to allogeneic RBC, B) Number of units of allogeneic RBC per patient, C) infections, D) mortality rate
Supplemental Digital Content 8: Quality management.
Studies were assessed for quality of washed cell salvaged blood.
Quality management
Only 2 studies1,2 reported detailed data on quality of washed cell salvaged blood. Both studies reported higher Hb and hematocrit level in cell salvaged blood than in donor blood. Additionally RBC morphology of cell salvaged blood was normal with mean corpuscular volume compared to donor RBCs. Levels of 2,3-diphosphoglycerate were elevated and more alike fresh blood than of stored allogeneic RBCs. However both studies reported increased amount of white blood cells in cell salvaged fraction, which was highly likely caused through inadequate washing processes.
1Elawad, A. A., Ohlin, A. K., Berntorp, E., Nilsson, I. M. & Fredin, H. Intraoperative autotransfusion in primary hip arthroplasty. A randomized comparison with homologous blood. Acta orthopaedica Scandinavica62, 557-562 (1991).
2Farrer, A., Spark, J. I. & Scott, D. J. Autologous blood transfusion: the benefits to the patient undergoing abdominal aortic aneurysm repair. Journal of vascular nursing : official publication of the Society for Peripheral Vascular Nursing15, 111-115 (1997).
Supplemental Digital Content 9: Cost analysis.
Studies were assessed for cost report.
Cost
Five trials undertook cost analysis using different variables for cost estimation with different outcome. Three studies1-3 showed no differences in costs between cell salvage and control group whereas one study4 reported increased and one study5 decreased costs upon usage of cell salver technology. However, only one study3 provided detailed information about cost calculation in that data were collected until 30 day after submission. For analysis of the duration of surgery, length of hospitalization and postoperative ward, drug use, re-admission after initial hospital discharge, and visits with general practitioner and home health nurse were taken into account. Furthermore, cost calculation for the use of cell salvage per patient included supply of device and consumables, servicing, repairs and training. Additionally costs of operating room, intensive care unit, ward bed day cost, standard tests, consumables, staff and overhead costs were also calculated. No statistical differences could be observed in the total or grouped cost analysis (data not shown).
1Bowley, D. M., Barker, P. & Boffard, K. D. Intraoperative blood salvage in penetrating abdominal trauma: a randomised, controlled trial. World J Surg30, 1074-1080, doi:10.1007/s00268-005-0466-2 (2006).
2Damgaard, S. & Steinbruchel, D. A. Autotransfusion with cell saver for off-pump coronary artery bypass surgery: a randomized trial. Scand Cardiovasc J40, 194-198, doi:10.1080/14017430600628292 (2006).
3Klein, A. A. et al. A randomized controlled trial of cell salvage in routine cardiac surgery. Anesthesia and analgesia107, 1487-1495, doi:10.1213/ane.0b013e3181831e54 (2008).
4Thomas, D., Wareham, K., Cohen, D. & Hutchings, H. Autologous blood transfusion in total knee replacement surgery. British journal of anaesthesia86, 669-673 (2001).
5Savvidou, C., Chatziioannou, S. N., Pilichou, A. & Pneumaticos, S. G. Efficacy and cost-effectiveness of cell saving blood autotransfusion in adult lumbar fusion. Transfus Med19, 202-206, doi:10.1111/j.1365-3148.2009.00929.x (2009).