Academic Surgery Unit, Education and Research Centre, South Manchester University Hospital, Southmoor Road, Manchester M23 9LT, UK
Correspondence to: Mr Francesco Torella E-mail: FCMTDR{at}aol.com
| SUMMARY |
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After introduction of the policy, the proportion of patients transfused fell from 57% to 45% with CABGs (P=0.02) and from 52% to 26% with hip replacements (P=0.006); for colectomies and TURPs there was no change. Hospital stay did not increase in any of the groups. In the second period, haemoglobin concentration on discharge was lower after total hip replacement, by a mean (95% CI) of 0.7 (0.3-1.2) g dL-1 (P=0.002) and after colectomy, by a mean of 0.6 (0.1-1.1) g dL-1 (P=0.03).
Although other factors cannot be excluded, we suggest that the reductions in red-cell transfusion were in large part attributable to the new transfusion policy.
| INTRODUCTION |
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The transfusion committee at South Manchester University Hospital produced a policy for red-cell transfusion in October 1999, including a standard blood ordering schedule and a transfusion trigger of a haemoglobin concentration <8 g dL-1 in the absence of symptoms. To assess the impact of this trigger on transfusion practice, we audited transfusion requirements in surgery over two periods of six monthsbefore the guidelines, from 1 January 1999 to 30 June 1999; and after the guidelines, from 1 November 2000 to 30 April 2001. The second period was one year after introduction of the transfusion policy to allow full dissemination and implementation.
| METHODS |
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Proportions were compared with the
2 test. Continuous
variables were expressed as mean and standard deviation (SD) if normally
distributed (haemoglobin concentration) and as median and interquartile range
(IQR) if skewed. The former were compared by the unpaired t test and
the latter by the MannWhitney U test.
| RESULTS |
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Coronary artery bypass grafts
The median (IQR) number of crossmatch requests was 1 (1-1) in both periods
(P=0.53). 114/200 patients (57%) were transfused before and 90/200
(45%) after introduction of the transfusion policy (P=0.02). The
median (IQR) volume transfused was 1 (0-2) units before and 0 (0-2) units
after introduction of the policy (P=0.12). There was no significant
difference in haemoglobin concentration on admission or discharge between the
two periods (Table 1). The
median (IQR) inpatient stay was 11 (9-15) days in the first period and 10
(8-13) in the second.
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Total hip replacement
The median (IQR) number of crossmatch requests was 1 (1-2) in the first
period and 1 (1-1) in the second (P=0.33). 26/50 patients (52%) were
transfused in the first period and only 15/57 (26%) in the second
(P=0.006). The median (IQR) volume transfused was 2 (0-3) units
before and 0 (0-1.5) units after introduction of the transfusion policy
(P=0.003). Haemoglobin concentration on discharge was lower by a mean
(95% CI) of 0.7 (0.3, 1.2) g dL-1 (P=0.002) after
introduction of the transfusion trigger (see
Table 1). The median (IQR)
inpatient stay was 10 (8-13) days in the first period and 9 (7-13) days in the
second.
Colectomy
The median (IQR) number of crossmatch requests was 1 (1-2) in both periods
(P=0.97). 24/45 patients (53%) were transfused in the first period
and 22/40 (55%) in the second (P=0.88). The median (IQR) volume
transfused was 2 (0-5) units in both periods (P=0.94). Haemoglobin
concentrations at admission were similar in the two periods but, on discharge,
concentrations were significantly lower after introduction of the transfusion
policy (see Table 1).
The median (IQR) inpatient stay was 16 (11-31) days before and 16 (12-25) days
after institution of the transfusion policy.
Transurethral prostectomy
The median (IQR) number of crossmatch requests was 0 (0-1) in both periods
(P=0.39). Only a minority of patients were transfused12/80
(15%) in the first period and 18/78 (23%) in the second (P=0.2).
Haemoglobin concentrations at admission and discharge did not differ in the
two periods (see Table
1). The median (IQR) inpatient stay was 7 (5-10) days in the first
period and 6.5 (5-9) in the second.
| DISCUSSION |
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A haemoglobin concentration <8 g dL-1 may seem restrictive as a transfusion trigger, but it is in line with recent published work9,10,11 and has lately been used by our group in a large randomized trial evaluating transfusion strategies in aortic surgery6,7,8.
There are several reasons why a reduction in homologous blood use is desirable. Aside from the obvious avoidance of complications, withholding unnecessary transfusions may spare patients the immunomodulatory effect of homologous blood, which is suspected by some of increasing susceptibility to bacterial infection12 or cancer recurrence13. There is also growing concern about future availability of blood stocks in view of the impending routine testing of all homologous blood products for the agent of variant CreutzfeldtJakob disease. It is impossible to predict how many will be excluded on the basis of the new test. Furthermore, many existing donors may be unwilling to undergo testing and may therefore be lost to the system.
Were the observed changes attributable to the transfusion policy or to other factors? Changes in personnel, new published data and the introduction of new procedures could have contributed to a change in attitudes to red-cell transfusion. There is greater reason to doubt a direct effect of the transfusion policy on hospital stay, which might have been influenced by factors such as pressure on beds.
Although the NHS Executive has recommended the institution of local transfusion policies, this may be difficult because objective transfusion triggers are lacking. Red-cell transfusion is given to restore or preserve adequate oxygen delivery to the tissues but haemoglobin, the best transfusion trigger currently available14, only measures blood oxygen carrying capacity. Haemoglobin is thus relatively unhelpful, in isolation, in most circumstances where red-cell transfusion is considered15; hospital transfusion committees will therefore need to be flexible in the enforcement of transfusion triggers. In conclusion, this study provides some evidence supporting the role of hospital transfusion committees in formulating local transfusion policies. Further reduction in the number of red-cell transfusions may require identification of alternative transfusion triggers.
| REFERENCES |
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