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. 2022 Jul 18;2022(7):CD008462. doi: 10.1002/14651858.CD008462.pub4

Schallom 2012.

Study characteristics
Methods Design: RCT, open‐label
Exclusions post‐randomisation: heparin group: n = 5; saline group: n = 1
Losses to follow‐up: heparin group: n = 9; saline group: n = 1
Duration of study: From April 2009 to May 2010
Unit of randomisation: catheter
Participants Country: USA
Setting: medical or surgical ICU patients
Number: 338 (heparin group: n = 172; saline group: n = 166)
Age: heparin group: 59.1 ± 15.2; saline group: 58.3 ± 17.5
Sex: heparin group: male/female 68/104; saline group: male/female 83/83
Inclusion criteria: patients had to have a newly inserted (< 12 hrs) multi‐lumen CVC.
Exclusion criteria: patients with multi‐lumen dialysis or apheresis catheters, PICC, long‐term use catheters, pulmonary artery catheters, implanted ports, large‐bore single lumen sheath catheters, and multi‐lumen catheters threaded through large bore sheath catheters; patients with double‐lumen catheters; known heparin allergy; diagnosis of HIT, bleeding risk identified by attending physician; age < 18 yrs; and pregnancy
Interventions Flushes every 8 hours with:
  • heparin 10 IU/mL, 3 mL

  • 0.9% NaCl, 10 mL


Prophylactic or therapeutic anticoagulation was used in both groups with non‐significant differences.
Outcomes Rate of lumen non‐patency, blood loss return, flush failure, rate of catheter‐related bloodstream infection, HIT
Follow‐up: 22 days
Funding Not reported
Declarations of interest Not reported
Notes  
Risk of bias
Bias Authors' judgement Support for judgement
Random sequence generation (selection bias) Low risk Investigators used a computerised random number generator in MS Excel.
Allocation concealment (selection bias) Low risk Quote: "The allocation sequence was concealed until the card was retrieved upon obtaining patient consent".
Blinding of participants and personnel (performance bias)
All outcomes Unclear risk Open‐label study. Insufficient information to permit judgement of ‘Low risk’ or ‘High risk’
Blinding of outcome assessment (detection bias)
All outcomes Unclear risk Open‐label study. Insufficient information to permit judgement of ‘Low risk’ or ‘High risk’
Incomplete outcome data (attrition bias)
All outcomes Low risk Only 2/166 in saline group and 14/172 in heparin group withdrew.
Selective reporting (reporting bias) Unclear risk Study protocol was not available, but it was clear that published reports included all expected outcomes, including those that were prespecified.
Other bias Unclear risk Not enough information to permit judgement of other bias

BMT: blood and marrow transplantation
CI: confidence interval
CVC: central venous catheter
h: hours
HIT: heparin‐induced thrombocytopaenia
ICU: intensive care unit
KVO: keep vein open
LMWH: low molecular weight heparin
MODS: multi‐organ dysfunction syndrome
NaCl: sodium chloride
PICCs: peripherally inserted central catheters
PT: prothrombin time
PTT: partial thromboplastin time
RCT: randomised controlled trial
RICU: respiratory intensive care unit
SD: standard deviation
SVC: superior vena cava
TIVAD: totally implantable vascular access device
TPN: total parenteral nutrition