Background
- Adrenaline thought to play a role in pro-coagulation, through increased platelet numbers, aggregation and fibrinogen level
Hypothesis
- Epinephrine administration (iv) could reduced the perioperative blood loss in patients undergoing elective fast track THA
Method
- Randomized, double blind, parallel group, placebo controlled. Randomisation via block randomisation
- 2 Danish surgical centres between 2012-2013; ELECTIVE FAST TRACK THA patients only
- Strict inclusion and exclusion criteria based around co-morbidites likely to be exacerbated by adrenaline infusion (see paper for full list)
- Spinal anaesthetic (Bupivicaine 0.5%) – All received same dose. Standardized positioning, monitoring and no use of drains in any patients
- All subjects received 1g tranexamic acid
- Standardized fluid therapy -0.9% saline 12ml/kg/hr in first hour, then 6ml/kg/hr until end of surgery (last stitch). Blood loss replaced 1:1 with hydroxyethyl starch
- Post op – pts allowed to E+D, iv fluids at discretion of physician (not standardised)
Outcome measures
- Primary – intraoperative blood loss -Surgical nurse measuring suction drain contents and weighing swabs
- Secondary – Blood loss at 24 hours post op -Calculated using Gross formula and Nadler equation
Results
- 100 patient in each arm (adequately powered to detect 40% less blood loss to pilot study). All patients accounted for. Similar groups in terms of age, genders and ASA status.
- No significant change in blood loss intra op (P = 0.23). Statistically significant reduction in 24 hour blood loss of 184ml (p=0.04).
- No patients given blood transfusion
Pros:
- First study of its kind
- Clear – hypothesis, randomisation and blinding process
- Adequate power; Similar groups
- Maximal attempts to treat to groups equally intra op (bar sedation)
- All patients who entered trial accounted for
- Overall good attempt to minimise any bias
Cons:
- Given no patients received blood transfusion, perhaps time effort and money would be better spent looking at high risk groups of patients where blood conservation is more needed.
- No link to underlying mechanism of coagulation attempted
- Long term complications not followed up
- Confounders leading to lower Hbs post op such as SIRS/sepsis not looked for.
- Limited information on patient co-morbidities provided
summary by Dr Evan Wild
