Does washing swabs increase the efficiency of red cell recovery by cell salvage in aortic surgery?

BACKGROUND AND OBJECTIVES: We investigated the contribution of swab washing to the efficiency of red cell recovery by intraoperative cell salvage (ICS) in 10 patients undergoing elective aortic aneurysm repair. MATERIALS AND METHODS: Volumes and haemoglobin (Hb) concentrations were recorded in the blood recovered by direct suction and from washed swabs, both before and after processing with a Haemonetics Cell Saver 5. RESULTS: The mean +/- standard deviation (SD) estimated blood loss was 991 +/- 403 ml, resulting in a mean +/- SD salvaged RBC volume of 380 +/- 124 ml. The median [interquartile (IQR) range] Hb collected from suction was 84.9 (61.8-131.4) g, of which 50.1 (45-71.5) g was returned to the patient after processing, a median yield of 68 (49-77)%. The swab wash produced a median (IQR) Hb of 39.4 (28.4-64.9) g, of which 26.2 (16.8-31) g was reinfused, a 67 (33-98)% yield. Swab wash thus contributed with a median (IQR) of 31 (24-39)% of the total RBC recovery. CONCLUSIONS: Washing swabs improves the efficiency of red cell recovery by ICS.

Cerebral and peripheral near-infrared spectroscopy: an alternative transfusion trigger?

BACKGROUND AND OBJECTIVES: To develop a transfusion trigger based on tissue oxygenation, near-infrared spectroscopy (NIRS) was evaluated in a model of compensated haemorrhage. PATIENTS AND METHODS: Regional haemoglobin oxygen saturation from the cerebral cortex (CsO2) and the gastrocnemius muscle (PsO2) was monitored (using an INVOS 4100 near-infrared oximeter) in 30 patients during acute normovolaemic haemodilution to a target haemoglobin of 11 g/dl. Arterial oxygen saturation, end-tidal carbon dioxide tension, mean arterial pressure and haemoglobin concentration were also measured. RESULTS: During blood collection, CsO2 and PsO2 fell by a mean (95% CI) of 8 (5.3-10.7)% (P < 0.001) and 5.5 (3.2-7.8)% (P < 0.001), respectively. Arterial pressure and oxygen saturation did not change, whilst the end-tidal carbon dioxide tension fell by 2.3 (0.8-3.8) mmHg (P = 0.004). Haemoglobin concentration correlated with CsO2 (R = 0.76, P < 0.001) and PsO2 (R = 0.63, P < 0.001), as did the volume of blood removed. CONCLUSIONS: CsO2 and PsO2 fell predictably during compensated blood loss. With further research, NIRS may be developed into a transfusion trigger.

Economic evaluation of a randomized clinical trial of haemodilution with cell salvage in aortic surgery.

BACKGROUND: This study evaluated the costs of acute normovolaemic haemodilution (ANH) and intraoperative cell salvage (ICS) versus homologous blood transfusion in aortic surgery in a prospective multicentre randomized trial. METHODS: One hundred and forty-five patients were randomized either to standard transfusion practice (homologous) or to a combination of ANH and ICS (autologous). Costs for each inpatient admission were identified. Cell salvage costs were assigned on the assumption that 50 operations were done each year employing a trained cell salvage operator. The results were analysed statistically using bias-corrected bootstrap analysis. RESULTS: Patients who had transfusion of homologous blood received some 251 units and those having a homologous transfusion received 103 units (P = 0.008). There was no difference in morbidity, mortality and duration of hospital stay. Transfusion-related mean costs were similar at 340 UK pounds for patients having a homologous transfusion and 357 UK pounds for those receiving autologous blood (mean difference 17 UK pounds (95 per cent confidence interval [c.i.]--184 UK pounds to 174 UK pounds); P not significant). There was also no significant difference in mean overall costs: 5859 UK pounds for homologous and 5384 UK pounds for autologous transfusion (mean difference--475 UK pounds (95 per cent c.i.--2231 UK pounds to 1342 UK pounds)). Sensitivity analysis showed that costs remained similar for 20 and 150 operations per annum. Exclusion of a dedicated cell salvage operator reduced autologous transfusion costs but did not have a significant impact on overall cost. CONCLUSION: Autologous transfusion is cost neutral in aortic surgery even when surgical activity is low.

The influence of homologous blood transfusion on immunity and clinical outcome in aortic surgery.

OBJECTIVES: To evaluate the influence of homologous blood transfusion on immune responses and post-operative morbidity in aortic surgery. DESIGN: Analysis of the effects of homologous blood transfusion in 128 patients in a prospective randomised trial evaluating homologous and autologous blood transfusion in aortic surgery. MATERIALS AND METHODS: Blood sampled before and at five times after surgery was assayed for C-reactive protein (CRP), neutrophil elastase, TNF-alpha and IL-6. Transfusions, morbidity and mortality were recorded; factors associated with poor outcome were identified by logistic regression. RESULTS: homologous transfusion during surgery was required in 32 patients and precipitated an increase in neutrophil elastase (p=0.008) and TNF-alpha (p=0.015) but not IL-6 and CRP. Elastase peaked early in transfused patients at 41.27 (13.92-52.11) Deltang/ml by 2 h compared to a peak of 21.51 (10.64-31.13) Deltang/ml by 24 h in those who were not transfused. TNF-alpha peaked at 1.2 (0-4.33) Deltapg/ml by wound closure in transfused patients and at -0.1 (-2.05-2.52) Deltapg/ml by 2 h without transfusion. Intra-operative homologous transfusion was associated with increased mortality (p=0.01) and prolonged intensive care stay (p=0.03). Mortality increased with age (p=0.003) and was inversely related to the CRP peak (p=0.007). Prolonged surgery predicted post-operative complications (p=0.025). CONCLUSION: Homologous transfusion increased the inflammatory response to aortic surgery and was associated with mortality.

Unchanging attitudes to autologous transfusion in the UK.

Our aim was to assess changes in attitudes to autologous transfusion amongst surgeons over a 10-year period in response to scientific evidence, public awareness, published guidelines, management and the increasing cost of blood products. Surgeons across the north-west of England completed questionnaires on knowledge, experience and attitude towards autologous transfusion in 1990, 1994 and 1999. Main outcome measures were changes in knowledge, experience and utilization of autologous transfusion; perceived advantages of autologous transfusion, obstacles to its implementation in surgical practice and preferences for specific techniques (preoperative autologous donation, acute normovolaemic haemodilution, intraoperative and postoperative cell salvage). There has been little change in practice over 10 years. Many more surgeons were keen to employ autologous transfusion than were using it. Autologous transfusion was only used in general, orthopaedic and cardiothoracic surgery. Safety and patient preference were the main arguments for implementation and logistics the main obstacles. Autologous transfusion was used sporadically in surgical practice. Clinical trials are needed to guide clinicians in the choice of transfusion techniques.

Keratinocytes express fibrillin and assemble microfibrils: implications for dermal matrix organization.

Fibrillin-containing microfibrils are key architectural structures of the upper dermis and integral components of the dermal elastic fibre network. Microfibril bundles intercalate into the dermal-epithelial junction and provide an elastic connection between the dermal elastic fibre network and the epidermis. Immunohistochemical studies have suggested that they are laid down both at the dermal-epithelial junction and in the deep dermis. While dermal fibroblasts are responsible for deposition of the elastin and microfibrillar components that comprise the elastic fibres of the deep dermis, the cellular origin of the microfibril bundles that extrude from the dermal-epithelial junction is not well defined. We have used fresh tissues, freshly isolated epidermis and primary human and porcine keratinocyte cultures to investigate the possibility that keratinocytes are responsible for deposition of these microfibrils. We have shown that keratinocytes in vivo and in vitro synthesize both fibrillin-1 and fibrillin-2, and assemble beaded microfibrils concurrently with expression of basement membrane collagen. These observations suggest that keratinocytes co-ordinate the secretion, deposition and assembly of these distinct structural elements of the dermal matrix, and have important implications for skin remodelling.