National comparative audit of blood use in elective primary unilateral total hip replacement surgery in the UK.

INTRODUCTION: Blood is a scarce and expensive product. Although it may be life-saving, in recent years there has been an increased emphasis on the potential hazards of transfusion as well as evidence supporting the use of lower transfusion thresholds. Orthopaedic surgery accounts for some 10% of transfused red blood cells and evidence suggests that there is considerable variation in transfusion practice. PATIENTS AND METHODS: NHS Blood and Transplant, in collaboration with the Royal College of Physicians, undertook a national audit on transfusion practice. Each hospital was asked to provide information relating to 40 consecutive patients undergoing elective, primary unilateral total hip replacement surgery. The results were compared to indicators and standards. RESULTS: Information was analysed relating to 7465 operations performed in 223 hospitals. Almost all hospitals had a system for referring abnormal pre-operative blood results to a doctor and 73% performed a group-and-save rather than a cross-match before surgery. Of hospitals, 47% had a transfusion policy. In 73%, the policy recommended a transfusion threshold at a haemoglobin concentration of 8 g/dl or less. There was a wide variation in transfusion rate among hospitals. Of patients, 15% had a haemoglobin concentration less than 12 g/dl recorded in the 28 days before surgery and 57% of these patients were transfused compared to 20% with higher pre-operative values. Of those who were transfused, 7% were given a single unit and 67% two units. Of patients transfused two or more units during days 1-14 after surgery, 65% had a post transfusion haemoglobin concentration of 10 g/dl or more. CONCLUSIONS: Pre-operative anaemia, lack of availability of transfusion protocols and use of different thresholds for transfusion may have contributed to the wide variation in transfusion rate. Effective measures to identify and correct pre-operative anaemia may decrease the need for transfusion. A consistent, evidence-based, transfusion threshold should be used and transfusion of more than one unit should only be given if essential to maintain haemoglobin concentrations above this threshold.

Silent myocardial ischaemia and haemoglobin concentration: a randomized controlled trial of transfusion strategy in lower limb arthroplasty.

BACKGROUND AND OBJECTIVES: Red cell transfusion is commonly used in orthopaedic surgery. Evidence suggests that a restrictive transfusion strategy may be safe for most patients. However, concern has been raised over the risks of anaemia in those with ischaemic cardiac disease. Perioperative silent myocardial ischaemia (SMI) has a relatively high incidence in the elderly population undergoing elective surgery. This study used Holter monitoring to compare the effect of a restrictive and a liberal red cell transfusion strategy on the incidence of SMI in patients without signs or symptoms of ischaemic heart disease who were undergoing lower limb arthroplasty. MATERIALS AND METHODS: We performed a multicentre, controlled trial in which 260 patients undergoing elective hip and knee replacement surgery were enrolled and randomized to transfusion triggers that were either restrictive (8 g/dl) or liberal (10 g/dl). Participants were monitored with continuous ambulatory electrocardiogram (ECG) (Holter monitoring), preoperatively for 12 h and postoperatively for 72 h. The tapes were analysed for new ischaemia by technicians blinded to treatment. The total ischaemia time in minutes was divided by the recording time in hours and an ischaemic load in min/h was calculated. Haemoglobin levels were measured preoperatively, postoperatively in the recovery room, and on days one, three and five after surgery. RESULTS: The mean postoperative haemoglobin concentration was 9.87 g/dl in the restrictive group and 11.09 g/dl in the liberal group. In the restrictive group, 34% were transfused a total of 89 red cell units, and in the liberal group 43% were given a total of 119 red cell units. A postoperative episode of silent ischaemia was experienced by 21/109 (19%) patients in the restrictive group and by 26/109 (24%) patients in the liberal group [mean difference -4.6%; 95% confidence interval (CI): -15.5% to 6%, P = 0.41). There was no significant difference (P = 0.53) between the overall ischaemic load in the restrictive group (median 0 min/h, range 0-4.18) and the liberal group (median 0 min/h, range 0-19.48). In those patients who did experience postoperative SMI, the mean ischaemic load was 0.48 min/h in the restrictive group and 1.51 min/h in the liberal group (ratio 0.32, 95% CI: 0.14-0.76, P = 0.011). The median postoperative length of hospital stay in the restrictive group was 7.3 days [range 5-11; interquartile range (IQR) 6-8] compared with 7.5 days (range 5-13; IQR 7-8) in the liberal group. The numbers were not large enough to conclude equivalence. CONCLUSIONS: In patients without preoperative evidence of myocardial ischaemia undergoing elective hip and knee replacement surgery, a restrictive transfusion strategy seems unlikely to be associated with an increased incidence of SMI. A proportion of these patients experience moderate SMI, regardless of the transfusion trigger. Use of a restrictive transfusion strategy did not increase length of hospital stay, and use of this strategy would lead to a significant reduction in red cell transfusion in orthopaedic surgery. Our data did not indicate any potential for harm in employing such a strategy in patients with no prior evidence of cardiac ischaemia who were undergoing elective orthopaedic surgery.

Which groups of patients are transfused? A study of red cell usage in London and southeast England.

BACKGROUND AND OBJECTIVES: There are few published data on the use of red blood cells (RBC) by specialty in the United Kingdom. The aim of this survey was to identify major specialty users of blood to target for audit of transfusion practice with a view to minimizing inappropriate use and to support planning of blood supply needs for the future. MATERIALS AND METHODS: Data were collected retrospectively of RBC units transfused at 62 hospitals/trusts in London and southeast England between April 1997 and March 1998. RESULTS: A total of 594 810 transfused RBC units were successfully traced to their respective clinical specialties, representing 91.9% of all RBC units issued to the study hospitals. Of the RBC units transfused, 51.2% were transfused in surgical, 36.0% in medical and 12.8% in "combined" specialties. CONCLUSIONS: This large study has accurately documented the clinical disciplines that are significant users of RBCs in our service area. It has heightened general understanding of RBC usage within hospitals. It has also raised questions on future strategies for reducing allogeneic blood transfusion that will be important if anticipated major reductions in blood supply occur in the near future.

Effectiveness of a protocol to improve transfusion practice in knee replacement surgery.

BACKGROUND AND OBJECTIVES: The available guidelines on red cell transfusion are not clearly defined and therefore have had only a modest impact on transfusion practice. The aims of this study were to assess the rate of compliance with a transfusion algorithm and its effect on transfusion practice. MATERIALS AND METHODS: A prospective observational study was carried out on 101 patients who underwent primary elective total knee replacement surgery. RESULTS: Only 30% of the patients were transfused. An overall compliance rate of 77% was achieved with the transfusion algorithm. CONCLUSION: A transfusion algorithm, together with staff education, is effective in reducing both the number of patients transfused and inappropriate transfusions.

Retrospective study on red cell usage in primary total knee replacement surgery.

BACKGROUND AND OBJECTIVES: There is wide variation in the use of red cell transfusions for the same clinical indication. The purpose of the study was to comment on preoperative and discharge haemoglobin (Hb) levels and perioperative blood loss, and to project the Hb level if transfusions were not administered. MATERIALS AND METHODS: The case notes of 187 patients who underwent primary total knee replacement were reviewed retrospectively. RESULTS: More than 90% of the transfusions were given in the immediate postoperative period as a matter of routine and a significant number of transfusions appeared to be unnecessary. CONCLUSION: For surgical procedures involving moderate blood loss, transfusions should not be given as a routine and the decision to transfuse should take into consideration the clinical state of the patient, blood loss and pre- and postoperative Hb levels.

C-reactive protein in patients undergoing cardiac surgery.

Among 25 patients undergoing cardiac surgery with the aid of cardiopulmonary bypass, 13 who recovered uneventfully all had normal (less than 2 mg/litre) levels of serum C-reactive protein pre-operatively. In contrast, 10 of the 12 patients who suffered from various postoperative complications, including two who died, had abnormally raised levels of C-reactive protein pre-operatively. All patients showed a major acute phase response to surgery with peak C-reactive protein levels at about 46 hours but, whereas the uncomplicated cases showed a characteristic smooth biphasic pattern of declining levels thereafter, the complicated cases all exhibited significant alterations of this pattern. The occurrence during the postoperative period of a secondary rise in C-reactive protein or the failure of the level to continue falling, generally preceded clinical evidence of intercurrent infection. Pre-operative measurement of serum C-reactive protein may thus make a valuable contribution to the assessment of patients requiring elective cardiac surgery; regular postoperative monitoring can provide early warning of serious complications.

Cardiovascular response to intubation. A comparative study of thiopentone and midazolam.

The cardiovascular response evoked by tracheal intubation was observed in 20 patients undergoing elective abdominal surgery in whom anaesthesia was induced with either midazolam 0.3 mg/kg or thiopentone 4.5 mg/kg followed by pancuronium 0.1 mg/kg. In the thiopentone group, intubation caused a mean rise in systolic arterial pressure from 141 to 193 mmHg (p less than 0.0005) and in the heart rate-systolic pressure product from 11101 to 21763 (p less than 0.05); 5 minutes later the mean values were still 173 mmHg and 19030 respectively. In the midazolam group systolic arterial pressure and the rate pressure product increased from 138 to 151 mmHg and 10960 to 14267 respectively in response to intubation. These values were significantly lower than the thiopentone group (p less than 0.005 in each case) and were relatively transient and returned to control values within 5 minutes.

Perioperative changes in complement associated with cardiopulmonary bypass.

The total haemolytic complement (CH50), the complement components C3 and C4, the complement breakdown product C3d, alternative pathway activation and transferrin, were measured before, during and after cardiopulmonary bypass. As expected, CH50 decreased after heparinization, remained low during bypass and decreased further up to 8 h after bypass. C3 and C4 decreased significantly during bypass, continued to decrease for a further 8 h after bypass (by 35% and 40% respectively) and thereafter increased gradually up to 48 h. Although the depletions observed were suggestive of complement activation, there were no demonstrable increases in C3d, and in all patients the concentration of C3d remained within the normal range. Hence it was concluded that complement depletions of this magnitude were unlikely to result from complement activation. Non-specific changes in protein concentrations during bypass, as a result of dilution, redistribution or other unidentified factors, are more probable causes of the observed reductions. The acute phase response to surgery may be a factor in the subsequent increase in C3 and C4 which is seen 24 h after bypass. As transferrin concentrations in the plasma are known to decrease during this response the observed decrease in transferrin concentration would support this view.

Complement in CPD-stored blood.

We studied complement functions, breakdown of C3 and aggregation of immunoglobulins in whole blood stored in citrate phosphate dextrose at 4 degrees C for up to 3 weeks from 10 normal blood donors. No significant changes in total haemolytic complement (CH50) and alternative pathway haemolytic complement activity were detected. However, the complement-mediated capacity of the sera to solubilise a pre-formed immune precipitate decreased significantly at 2 and 3 weeks (p less than 0.02 at 2 weeks, p less than 0.003 at 3 weeks). No C3 conversion could be detected by immunoelectrophoresis but alteration in C3 was attested by a significant increase in breakdown products of C3 by 1 week (p less than 0.002) and all were above the normal range after 3 weeks (p less than 0.0001). No aggregation of immunoglobulins could be detected using two immune complex assays.

Coagulation inhibitor in hypothyroidism.

A patient was referred for investigation of heavy bleeding after surgery. He showed several features of hypothyroidism but no goitre. Primary autoimmune hypothyroidism was confirmed by the finding of a low serum thyroxine concentration and a high thyrotropin concentration. Factor VIII concentration was low, and a mild coagulation inhibitor was found. The patient was treated with thyroxine and returned to normal health within a few months. The inhibitor found in this patient may have been specific for factor VIII, but the presence of coagulation inhibitors should be considered in patients with hypothyroidism.

Simultaneous or spontaneous occurrence of lympho- and myeloproliferative disorders: a report of four cases.

We describe four patients with mixed lympho- and myeloproliferative disorders. One patient had hairy cell leukaemia and acute myelomonocytic leukaemia, another lymphocytic lymphoma in leukaemic phase and chronic myelomonocytic leukaemia and the third patient had chronic lymphocytic leukaemia and polycythaemia rubra vera; none of these patients had received any prior therapy, and in two the diagnosis of the two malignancies was simultaneous. The fourth patient developed acute monocytic leukaemia 4 years after the diagnosis of chronic lymphocytic leukaemia after only 2 weeks of therapy with chlorambucil. The nuber of cases with concurrent or sequential but spontaneous occurrence of lympho- and myeloproliferative disorders reported so far is now 38. The questions relating to the pathogenesis of the two malignancies are discussed.

Methohexitone or etomidate for induction of dental anaesthesia.

Ninety-two patients who presented for outpatient dental extractions received methohexitone (1.5 mg . kg-1, 46 patients) or etomidate (0.3 mg . kg-1, 23 patients and 0.2 mg . kg-1, 23 patients). The induction characteristics of both drugs such as pain on injection, involuntary muscle movements and respiratory difficulties were comparable and the theoretical disadvantages of etomidate for dental anaesthetics did not prove troublesome in practice. Muscle movements did not interfere with the dentists' manipulations and pain on injection into veins of the antecubital fossa did not occur. The duration of operation for up to four extractions was three minutes and, following induction, anaesthesia was maintained with nitrous oxide, oxygen and halothane. Recovery was assessed by grading consciousness, airway control and motor activity. All the patients could maintain their airways one minute after the end of operation. The incidence of nausea and vomiting was significantly greater in the etomidate group.

Clonazepam in the treatment of choreiform activity.

In a limited study, clonazepam, a new benzodiazepine derivative, has been found to be effective in suppressing choreiform movements in three patients with Huntington's chorea, three patients with non-familial chorea, and in one patient with senile chorea. In two patients with chorea of doubtful aetiology the response was not very satisfactory. A simple method was used to assess objectively the effect on choreiform movements. The effective dose varied from 3-5 to 5-5 mg a day. The drug was well tolerated by most of the patients.