1. Thromboprophylaxis in ICU
Thomas Li
Consultant respiratory physician
Union Hospital
Thromboprophylaxis in ICU

2. Receive no sponsorship from any drug company or medical device company Declare no conflict of interest with any drug company or medical device company

3. Guidelines of VTE prophylaxis
Development of local guideline
Mechanical methods of VTE prophylaxis
Other strategies for early detection of VTE
Routine USG screening
Low threshold CTPA
Restriction of sedation
Early rehabilitation

4. If you are preparing for an ICU exam

5. International guidelines
American College of Chest Physicians
Surviving Sepsis Campaign
Institute of Healthcare Improvement
National Institute of Health and Care Excellence

6. Who are at risk ? Medical patients Surgical patients
Mobility significantly reduced ≥ 3 days
Reduced mobility + any VTE risk
Surgical patients
Anaesthetic time > 90 minutes
Anaesthetic time > 60 minutes + operation involves pelvis or lower limb
Acute surgical admission with inflammatory or intra-abdominal
Expected reduced mobility
Any VTE risk factors
NICE guideline

7. Increased risk of VTE Active cancer or cancer treatment
Age > 60 years
Intensive care admission
Dehydration
Known thrombophilia
BMI > 30
1 or more significant medical comorbidity
Personal or family history of VTE
Use of HRT or contraceptive
Varicose veins with phlebitis
NICE guideline

8. Increased risk of bleeding
Active bleeding
Acquired bleeding disorders eg liver failure
Concurrent use of anticoagulant
LP, epidural or spinal anaesthesia in coming 12 hours
LP, epidural or spinal anaesthesia within past 4 hours
Acute stroke
Platelet < 75
BP > 230/120
Untreated inherited bleeding disorders

9. Position statement on prevention of VTE in ICU in HK
Local epidemiological studies without pharmacological prophylaxis
Mixed ICU patients: 11% with femoral vein cannulation had iliofemoral DVT (Joynt et al. CHEST 2000)
Medical ICU patients: 8% above knee DVT, 11% below knee (Joynt et al. HKMJ 2009)

10. Other Asian countries
10.5% (20/190) surgical ICU patients without thromboprophylaxis in Thailand had DVT
4.7% (9/190) were proximal DVT
3.7% (7/190) had PE confirmed by CT
(Asian J Surg 2009;32:85)
In a neurorehab ward in Singapore
98% not on heparin
77% Chinese, 14% Malay, 7% Indian
Proximal DVT 2.6%(11/419), distal 2.4%(10/419)
(Arch Phys Med Rehabil 2008)

11. Position statement on prevention of VTE in ICU in HK
Graduated compression stockings (GCS) and intermittent pneumatic compression (IPC) devices are commonly used
Most except a few ICUs use pharmacological DVT prophylaxis

12. Position statement on prevention of VTE in ICU in HK
No RCT on prevention of VTE in Chinese critically ill patients could be identified
5 RCT on prevention of VTE in Chinese patients could be identified

13. Thromboembolic prophylaxis for TK arthroplasty in Asian patients
DVT/ PE
Control
Number (%)
GCS
IPC
Enoxaparin
P-value
Overall
24 (22)
14 (13)
9(8)
6 (6)
0.001
Proximal DVT
3 (3)
1 (1)
0 (0)
0.279
Distal
DVT
21 (19)
13 (12)
9 (8)
5 (5)
0.003
Symptomatic PE
0.571
> 90% were ethnic Chinese
Journal of Orthopaedic surgery 2009

14. Thromboembolic prophylaxis for TK arthroplasty in Asian patients
Compare
% of DVT
P value
Control vs GCS
22 vs 13
0.119
Control vs IPC
22 vs 8
0.032
Control vs enoxaparin
22 vs 6
0.001

15. Bleeding complications
Control
GCS
IPC
Enoxaparin
Median transfusion
Units/person
0.1
0.2
0.34
Bleeding complications
Number of patients 3 4 9

16. Authors support use of IPC instead of LMWH

17. LMWH as DVT prophylaxis for Asian colorectal surgical patients
Enoxaparin 20 mg Q12H preop
Enoxaparin 40 mg daily for at least 4 days post-op
5/169 in control group had DVT, 3 out of the 5 DVTs also had acute pulmonary embolism
0/134 on enoxaparin had DVT/ PE (P=0.045)
3/169 in control had bleeding related complications
9/169 had bleeding complications (1 subdural haematoma and 2 intra-abdominal bleed exploration) (P=0.037)
Authors supported use of LMWH
Dis Colon Rectum 1999

18. DVT in HK Chinese with hip fractures: Incidence and effects of LMWH
37% (29/ 78) developed DVT
No difference in incidence between 2 groups
LMWH may reduce proximal DVT
Arch Orthop Trauma Surg 1999

19. Position statement on prevention of VTE in ICU in HK
Best available evidence do not address the benefits and risks of Chinese critically ill patient regarding pharmacological prophylaxis
RCT in Chinese critically ill patients are needed

20. End of discussion ?

21. What else can we use to prevent/ manage DVT or VTE ?
Mechanical devices
Routine screening
Low threshold for CT
Early mobilization

22. How effective in mechanical devices ?
Systemic review
MEDLINE, EMBASE, Biosis, Derwent
Mostly surgical patients
Mechanical devices (GCS or IPC or foot pump)
reduce risk of DVT by 2/3 as monotherapy
reduce risk of DVT by ½ when combined with pharmacological prophylaxis
reduce risk of proximal DVT by ½
Reduce risk of PE by 2/5
Health Technology Assessment 2005

23. ACCP 2008 guideline Appropriate size Proper fitting Compliance Storage
Disinfection

24. Is graduated compression stocking (GCS) harmless ?
CLOTS 1 study
Multi-centre, international, UK, Australia and Italy
2518 patients admitted to hospital within 1 week of onset of acute stroke
> 80% were ischaemic stroke
Randomized thigh length GCS or control
USG at day7-10 and day 28-30
CLOTS trial collaboration Lancet 2009

25. Is graduated compression stocking (GCS) harmless ?
GCS Control
Proximal DVT 10% 10.5%
Skin ulcers
Blisters 5% 1%
Necrosis

26. CLOTS 2 trial: Thigh-length vs below knee stockings for DVT prophylaxis after stroke
Multi-centre, international randomized
3114 patients hospitalized within 1 week of acute stroke (>80% were ischaemic)
Thigh length DVT or below knee DVT
Prematurely stopped enrollment because of results of CLOTS 1 trial
Ann Intern Med 2010

27. Thigh length Below-knee
CLOTS 2 trial: Thigh-length vs below knee stockings for DVT prophylaxis after stroke
Thigh length Below-knee
Proximal
DVT 6.3% 8.8% P=0.008
Death 10.9% %
Any skin
Problem 9% 6.9% P=0.03
Skin
Breakdown 3.9% 2.9%

28. Why ?
Risk of DVT
No stocking = Thigh length stocking < below knee stocking
? Increased risk of DVT with below knee DVT
If we believe the results, avoid the use of GCS for DVT prevention in patients after stroke

29. Why screen for DVT ?
It is present among our patients, but may be of lower prevalence than other ethnic groups
Controversy in use of pharmacological prophylaxis
Some patients have obvious contraindication to heparin or LMWH and may need IVC filter
It is clinically silent

30. DVT is clinically silent in ICU
239 patients surgical-medical
ICU patients
Twice weekly USG
Structural clinical examination
DVT risk score calculated
Journal of Critical Care 2005

31. DVT is clinically silent in ICU
DVT risk scores used in symptomatic outpatients were not applicable in ICU
Universal prophylaxis or routine screening

32. Potential risk factors in critically ill Chinese medical ICU patients
Only 4/15 of
Confirmed DVT had signs
11/15 had no signs
Joynt et al HKMJ 2009

33. Routine USG screening for DVT
Very few ICUs have access to portable ultrasound for diagnosis of DVT
Impractical to transport critically ill patients to radiological department regularly & frequently for ultrasound examination
Can intensivists do USG for diagnosis ?

34. A common scenario when I am on call in ICU
One night at 2 am, an ICU nurse call you patients in bed 1, 4, 5 and 7 have “desaturations”
What will be your reply ?

35. Your reply Ask the nurse to continue observation & sleep
Examine each patients and reassure the nurse
Examine each patients + ECG
Examine each patients + ECG + portable CXR
Examine each patients + ECG + portable CXR + wake up the on-call radiologist for urgent CT pulmonary angiogram

37. Diagnosis of acute pulmonary embolism in critically ill

38. Continuous SpO2 monitoring and static lung compliance
Continuous SpO2 and diagnosis of pulmonary embolism in critically ill trauma patients
Continuous SpO2 monitoring and static lung compliance
>10% drop in SpO2 and no change in compliance
48 out of 972 critically ill trauma patients in 18 months
44% of these patients had PE demonstrated using pulmonary angiogram
J Trauma 2001

39. Virchow’s triad Hypercoagulability
Haemodynamic changes (Stasis or turbulence)
Endothelial damages or dysfunction

40. Daily interruption of sedation
Intervention
N= 68
Control
N= 60ntrol
P-value
Duration of mechanical ventilation
4.9
7.3
0.004
ICU stay
6.4
9.9
0.02
Hospital stay
13.3
16.9
0.19
Extubation rate 4% 7%
0.88
Kress et al. NEJM 2000

41. No sedation for critically ill on mechanical ventilation: RCT
Sedation with daily interruption
P-value
Days without ventilation
13.8
9.6
0.019
ICU stay
13.1
22.8
0.032
Hospital stay 34 58
0.004
Agitation
20%
4.7%
Lancet 2010

42. Early mobilization in ICU
Daily interruption of sedation + early mobilization
Daily interruption of sedation
P-value
Return to independent daily living at hospital discharge
59%
35%
0.02
Duration of delirium
2 days
4 days
Ventilator-free days
23.5
21.1
0.05
Lancet 2009

43. Recommendations Multidisciplinary approach to prevent VTE
Early mobilization and rehabilitation
Reduction in use of sedatives and muscle relaxants
Compression devices for patients with high bleeding risks
Avoid femoral vein cannulation
Frequent regular USG screening for DVT

44. Recommendations Remove central venous catheters as soon as possible
Low threshold for CT pulmonary angiogram for unexplained hypoxaemia
Consider pharmacological prophylaxis after balancing the risks and benefits

45. What the colleges and society can do ?
Encourage collaboration between different ICU for multicenter studies on local Chinese patients
Liaise with college of radiology to organize recognized training in ultrasound diagnosis of DVT for intensivists