Frequently Asked Questions

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1.  What blood pressure (BP) do I use to document hypotension?

The BP immediately preceding the start of vasopressors should be used.  In cases where vasopressors are initiated prior to or in conjunction with fluid resuscitation, the BP must continue to meet inclusion criteria after fluid resuscitation.

2.  When randomized to therapeutic unfractionated heparin (UFH) do I add the time of interruptions to the total time of study drug infusion?

No.  UFH will be infused for 120 hours from the start time.  Time will not be added for interruptions.

3. Can a participant be enrolled if Continuous Renal Replacement Therapy (CRRT), Hemodialysis (HD), or Sustained low efficiency dialysis (SLED) is being used or if there are plans to use it?

A) Anticoagulation and CRRT/HD/SLED

Patients on CRRT/HD/SLED are eligible for HALO, but cannot receive ‘off protocol’ heparin.  Use of regional citrate is encouraged, or the circuits must be run ‘heparin free’ (note 50% of patients will receive heparin!).  If your centre does not use citrate with CRRT, increasing each the dialysate and return fluid to 2 litres/hour, could be considered to maximize filter life.  If recurrent filter clotting occurs despite effort, then the study should be suspended.

B) Heparin priming for CRRT

High aPTTs have been noted to occur after initiation of CRRT which may be related to heparin priming.  Please adopt the following priming guidelines:

*Perform an initial circuit prime with heparin. Perform a second prime with normal saline.

**When CRRT is initiated the circuit should be heparin free until day 5 or 120 hours regardless of which randomization group the patient is assigned.  

4. Is there an adjustment for a tympanic temperature when calculating the APACHE score?

No; tympanic temperature will be considered equivalent to core temperature. 

5. Can post-operative patients be enrolled?

Yes; providing there is no active bleeding and the local PI, attending physician and surgeon agree that the patient can receive therapeutic heparin doses.  If further surgery is expected, please refer to the suggested guidelines for invasive procedures (emergent and semi elective) located on page 77 of the procedure manual.  Clinical judgment will be required and should consider a patient’s bleeding risk and coagulation parameters.

6. When a patient is discharged from the ICU but is then readmitted, which ICU discharge date should be entered in the case report forms?

When a patient is re-admitted to the ICU please consider the following:

a) Is re-admitted within 36 hours of initial discharge:  Consider this the same ICU stay and do not enter a discharge date

b) Is re-admitted 36 hours after initial discharge:  Enter the first ICU discharge date.

7. What is considered the worst value of the day for vital signs and laboratory values?

If uncertain please use the Apache II as guidance.  The value with the most points should be used.