A 40-year-old previously well patient presents with a ruptured appendix and associated peritonitis. They return to theatre day 3 with ischaemic colitis requiring a right hemicolectomy. At laparotomy, there is extensive thrombosis in the superior mesenteric vein and portal vein. Attempts to anticoagulate the patient with heparin day 5 onwards have been unsuccessful.
The post-operative haematology results are as follows:
|
Day 0 |
Day 1 |
Day 3 |
Day 5 |
Day 7 |
Day 9 |
Reference |
|
|
INR |
1.2 |
1.7 |
1.8 |
1.6 |
0.8 – 1.3 seconds |
||
|
APTT |
36 |
38 |
36 |
28* |
31* |
37* |
24 – 35 seconds |
|
Fibrinogen |
5.8 |
1.8 |
1.4 |
1.7 |
2.0 – 5.0 g/L |
||
|
INR mix |
1.9 |
0.8 – 1.3 seconds |
|||||
|
APTT mix |
32.5 |
30 – 40 seconds |
|||||
|
D dimer |
>4.0 |
< 0.5 mg/L |
* On I.V. heparin
APTT therapeutic range for I.V. heparin therapy: 60 – 90 seconds
Additional tests performed on Day 7:
a) List the possible factors preventing therapeutic anticoagulation in this patient (2 marks)
b) List two strategies to achieve anticoagulation with intravenous heparin (2 marks)
Syllabus topic/section: 2.1.11 Haematological and Oncological Intensive Care
Discussion:
This was a repeat question and so a higher standard of performance was required. Poorly performing candidates frequently gave an incorrect interpretation for section 30.2 and/or failed to explain the mixing test in section 30.3. The relevance of normal tests in the questions were often misinterpreted or missed in the explanations candidates provided.