CHEST PAINGeneral Medical Emergencies 55(ii) In addition the CXR should be normal with no history of chronic
lung disease.
(iii) Unfortunately, over half the V/Q results will not help, i.e. are low
or intermediate probability results, and must still be followed
by further testing, such as CTPA or lower leg venous Doppler
ultrasound.MANAGEMENT1 Give high-dose oxygen through a face mask. Aim for an oxygen saturation
above 94%.
2 Relieve pain if it is severe with morphine 5 mg i.v. and give an antiemetic
such as metoclopramide 10 mg i.v.
3 Commence heparin in intermediate or high pre-test probability patients,
unless a diagnostic imaging test is imminently available, and contraindica-
tions such as active bleeding, thrombocytopenia, recent trauma or cerebral
haemorrhage are absent:
(i) Give LMW heparin such as enoxaparin 1 mg/kg s.c. or dalteparin
s.c. according to body weight, both 12-hourly.
(ii) Alternatively, give UF heparin 5000 units i.v. bolus, followed by
1000–1300 units/h infusion
(a) this is preferred with a major PE, as a first dose bolus or
according to local policy.
4 Admit all patients with a confirmed PE under the medical team, or if the test
results remain indeterminate.
(i) Arrange sequential testing with a V/Q scan then a CTPA or vice
versa, plus or minus a lower-limb venous Doppler ultrasound to
finally rule in or out the diagnosis.
(ii) Commence heparin once a positive result is confirmed, if not
already started.
5 Get help from a senior ED doctor for any apparent major, life-threatening PE
patient:
(i) Reserve thrombolysis with recombinant tissue plasminogen
activator (rt-PA) 10 mg i.v. over 1–2 min, then 90 mg over 2 h
(or 1.5 mg/kg maximum if under 65 kg) for patients with a
massive PE in shock, with acute right heart failure and systolic
hypotension.
(ii) Involve the intensive care team early.
Venous thromboembolism with deep vein thrombosis
DIAGNOSIS
1 Predisposing risk factors are as for venous thromboembolism. Up to two-thirds
of patients have acute provoking factors (see Table 2.2).