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BET 2: Is early chemical thromboprophylaxis safe in patients with blunt trauma solid organ injury (SOI) undergoing non-operative management (NOM)?
  1. Craig Ferguson,
  2. Jonathan Lewin
  1. Frimley Health NHS Foundation Trust, Surrey, UK

Abstract

A short cut review was carried out to establish whether chemical thromboprophylaxis was a safe early intervention in patients with solid organ injury that is being managed non-operatively. Eight papers presented the best evidence to answer the clinical question. The author, date and country of publication, patient group studied, study type, relevant outcomes, results and study weaknesses of these papers are tabulated. It is concluded that there is inadequate evidence assessing safety of low molecular weight heparin (LMWH) within 24 hours of trauma. The current available evidence does suggest that administration of LMWH within 48 hours is safe in non-operative management of patients who have sustained solid organ injury from blunt trauma.

  • emergency care systems

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Three-part question

In (patients with blunt abdominal trauma who have suffered solid organ injury that is being managed non-operatively) is (chemical thromboprophylaxis) a (safe early intervention)?

Clinical scenario

A 45-year-old man is brought to the ED having sustained significant trauma in a road traffic accident. From clinical examination and a trauma series CT scan he is diagnosed with grade 3 liver and splenic injuries. He remains haemodynamically stable with no evidence of ongoing bleeding. The initial plan is to manage him non-operatively. He is in significant discomfort and is not mobilising from bed. You wonder about the safety of prescribing low molecular weight heparin (LMWH) venous thromboembolism (VTE) prophylaxis in this situation.

Search strategy

Medline (1946 to September 2017), Embase (1974 to September 2017) and Cumulative Index to Nursing and Allied Health Literature (1981 to September 2017) via NHS NICE HDAS interface:

(thrombus* OR thrombotic* OR thrombolic* OR thromboemboli* OR thrombos* OR thromboph* OR deep* OR vein* or ven* OR thromb* or embol* OR pulmonary OR lung* OR thromb* OR embol* OR DVT or PE or VTE)

AND (solid organ injury OR organ injury OR blunt abdominal trauma OR abdominal injury OR Abdominal trauma OR blunt trauma OR abdominal organ injury OR splenic injury OR liver injury OR kidney injury OR splenic trauma OR liver trauma OR kidney trauma)

AND (thromboprophylaxis OR prophylactic* OR prophylaxis)

Cochrane Central Register of Controlled Trials (September 2017) and Cochrane Database of Systematic Reviews (September 2017).

Search outcome

Nine hundred and ten papers were identified and after reviewing title and abstract, 902 papers were excluded. The eight remaining papers are shown in table 2.

Table 2

Relevant paper(s)

Comments

Non-operative management (NOM) of blunt trauma solid organ injury (SOI) in haemodynamically stable patients has become standard practice of care.1 2 Venous thromboembolism (VTE) is a life-threatening complication of major trauma.3 Prothrombotic changes in physiology are hypothesised to occur within 48 hours following trauma.4 Chemical VTE prophylaxis is superior to mechanical VTE prophylaxis.5 Mechanical prophylaxis may be precluded in blunt trauma if there is associated lower limb injury. The American College of Chest Physicians and Eastern Association for the Surgery of Trauma clinical guidelines suggest early administration of chemical VTE prophylaxis,6 7 but do not specify its timing, and there is a lack of evidence to inform of its safety in early NOM of blunt trauma SOI. Most current evidence assessing the safety of early chemical thromboprophylaxis (LMWH or unfractionated heparin) are retrospective cohort studies. Retrospective cohort studies are vulnerable to selection bias as patients enter respective treatment arms based on the preference of the treating physician. In many of the studies included in this analysis, significant differences existed between the comparison groups. Discrepancies in these groups likely reflect the treating physicians reluctance to initiate LMWH in patients identified to have a high grade SOI or patients with a higher average injury severity score. Many of the studies available have relatively small sample sizes to detect differences in failure of NOM. Eberle et al reported failure of NOM for patients not receiving thromboprophylaxis of 7%,8 which means to detect a difference of 10% in failure rates with 80% power a study requires a sample size of 165 patients in each respective comparison group. Only two studies investigated administration of LMWH within 24 hours, Norwood et al in a prospective study which did not include a comparison group and Kwok et al who did not find that administration of LMWH within 24 hours increased failure rate of NOM or requirement of blood products. There are differences between the studies in patient population, chemical prophylaxis regimens, and the classification of early and late administration. Most studies used LMWH and defined early administration of LMWH as occurring within 48 hours. These studies show that administering LMWH within 48 hours does not increase failure rate of NOM or increase the requirement for blood products. These studies suggest that administration of LMWH within 48 hours is safe in patients who sustain SOI from blunt trauma being receiving NOM.

Clinical bottom line

There is inadequate evidence assessing safety of LMWH within 24 hours of trauma. The current available evidence of retrospective studies does suggest that administration of LMWH within 48 hours is safe in early NOM of patients who have sustained SOI from blunt trauma.

References

Footnotes

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; internally peer reviewed.

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