heparin infusion schedule
Last reviewed 01/2018
Check with local guidelines.
Example guidance:
Loading dose 5000 iu iv over 5 minutes
Initial infusion 25,000 iu heparin made up in saline to rate 50 ml gives a final concentration of 500 iu/ml, to be started at 2.8 ml/hr (1400 iu/hr)
Check APTT after 6 hours. Adjust according to APTT ratio (APTT: control) as follows:
| APTT ratio | infusion rate range |
| >7 | stop for 30 minutes to 1 hour and reduce by 500 iu/hr |
| 5.1-7.0 | reduce by 500 iu/hr |
| 4.1-5.0 | reduce by 300 iu/hr |
| 3.1-4.0 | reduce by 100 iu/hr |
| 2.6-3.0 | reduce by 50 iu/hr |
| 1.5-2.5 | no change - target range |
| 1.2-2.4 | increase by 200iu/hr |
| <2 | increase by 400 iu/hr |
After a change of schedule then APTT should be checked again after 10 hours. However if the APTT ratio is > 5.0 then the APTT ratio should be rechecked in 4 hours.