Pre-Operative Anaemia (BSH 2015)
Intro
Pre-op anaemia is a risk factor for complications and death from surgery
Mild anaemia (Hb >100) increase morbidity risk by 30%
It increases healthcare costs and risk of needing blood transfusion
Transfused patients have greater morbidity and mortality
DoH and National Blood Transfusion Committee recommend pre-op screening for anaemia
Three reasons for this
Identify previously undiagnosed disease, e.g. cancer
Reduce need for transfusion, conserving stocks
Reducing patient exposure to risks of blood transfusion
Timing of Assessment
No specific research, options include
With GP at time of referral, During the diagnostic pathway (e.g. abnormal endoscopy), Surgical Clinic, Pre-Op Assessment Clinic.
Suggested that testing with GP ideal as increase available time to correct anaemia.
Diagnosis of Anaemia
In a pre-op setting, most concerned with iron-related anaemia vs anaemia of other causes
Anaemia due to iron metabolism
Iron Deficiency Anaemia – insufficient absolute body iron stores
Functional Iron Deficiency – In sufficient iron available to bone marrow despite presence of iron in the reticulo-endothelial system.
Up to 15% of unexplained IDA —> malignancy
Approx 1% of hypoferritinaemia in men and menopausal women —> malignancy
Investigatory Algorithm
CCG’s should develop local pathways of investigation and agree funding arrangements between primary and secondary care
Correction of pre-op anaemia saves money in both domains
Management
General Considerations
Cause and severity of anaemia
Anticipated peri-op blood loss
Time available between diagnosis and surgery
Whether surgery may be safely postponed.
Oral Iron
Cheap, safe and widely available
Slow – at best Hb rise of 10g/l per week, and need to continue for further 3 months
Absorption impaired by tannins, PPIs, chronic inflammation, renal failure
Parenteral Iron
More rapidly effective than oral iron
Must be given in facilities with resus equipment – though SAEs <1 in 200,000
PREVENTT 2020 - approx 500 patients. 1g ferrinject vs placebo for pre-op anaemia of any cause prior to major abdo surgery. Given median of 15 days prior to surgery. No difference found in any of the primary outcomes or pre-specified subgroups. Surprising finding. ?Given too close to surgery and peri-op inflammation preventing effective utilisation of the iron.
Others
B12/Folate correction
Erythropoiesis-stimulating agents (ESA)
Recombinant variants of erythropoietin
Expensive, DVT side effects
Not recommended for pre-op anaemia unless in context of another licensed indications, e.g. renal failure
Short-term therapy
Very short therapy with IV Iron +/- daily ESA in one week prior to surgery
Shown to reduce transfusion requirement
But did not report on safety or adverse outcomes
Pre-op Transfusion
Not recommended, no good evidence for it despite previous widespread use