Infusions Mark Tomlin Consultant Pharmacist: Critical Care Southampton University Hospitals NHS...
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![Page 1: Infusions Mark Tomlin Consultant Pharmacist: Critical Care Southampton University Hospitals NHS Trust.](https://reader030.fdocuments.in/reader030/viewer/2022032612/56649ec95503460f94bd70eb/html5/thumbnails/1.jpg)
Infusions
Mark Tomlin
Consultant Pharmacist: Critical Care
Southampton University Hospitals NHS Trust
![Page 2: Infusions Mark Tomlin Consultant Pharmacist: Critical Care Southampton University Hospitals NHS Trust.](https://reader030.fdocuments.in/reader030/viewer/2022032612/56649ec95503460f94bd70eb/html5/thumbnails/2.jpg)
Characteristics of IV therapy
• Half-Life ?
• What Dose ?
• Intermittent Infusion ?
• How Often ?
• With Loading Dose ?
• Continuous Infusion ?
• Effect of organ dysfunction ?
![Page 3: Infusions Mark Tomlin Consultant Pharmacist: Critical Care Southampton University Hospitals NHS Trust.](https://reader030.fdocuments.in/reader030/viewer/2022032612/56649ec95503460f94bd70eb/html5/thumbnails/3.jpg)
Concentration – time
profile of an IV bolus
Con
cent
ratio
n
Time
![Page 4: Infusions Mark Tomlin Consultant Pharmacist: Critical Care Southampton University Hospitals NHS Trust.](https://reader030.fdocuments.in/reader030/viewer/2022032612/56649ec95503460f94bd70eb/html5/thumbnails/4.jpg)
Concentration – time
profile of an IV bolus
Con
cent
ratio
n
Time
An exponential decay
Cpt = Cp
0 x e-kt
![Page 5: Infusions Mark Tomlin Consultant Pharmacist: Critical Care Southampton University Hospitals NHS Trust.](https://reader030.fdocuments.in/reader030/viewer/2022032612/56649ec95503460f94bd70eb/html5/thumbnails/5.jpg)
Half-life
Con
cent
ratio
n
Time
10
5t
t
Described by a constant decay factor or:
![Page 6: Infusions Mark Tomlin Consultant Pharmacist: Critical Care Southampton University Hospitals NHS Trust.](https://reader030.fdocuments.in/reader030/viewer/2022032612/56649ec95503460f94bd70eb/html5/thumbnails/6.jpg)
Half-life - t
• Defined as the time taken for the concentration, of a drug, in the blood, to halve.
• We usually dose at the half-life• If the half-life is less than 4 hours then the
medicine is usually administered by infusion.• After 5 half-lives, the drug is completely
eliminated so it describes the duration in the blood
• Prescribe mg/kg/hr or μg/kg/min to remind staff about response delays after dose adjustments
![Page 7: Infusions Mark Tomlin Consultant Pharmacist: Critical Care Southampton University Hospitals NHS Trust.](https://reader030.fdocuments.in/reader030/viewer/2022032612/56649ec95503460f94bd70eb/html5/thumbnails/7.jpg)
Characteristics of IV therapy
• Half-Life ?
• What Dose ?
• Intermittent Infusion ?
• How Often ?
• With Loading Dose ?
• Continuous Infusion ?
• Effect of organ dysfunction ?
![Page 8: Infusions Mark Tomlin Consultant Pharmacist: Critical Care Southampton University Hospitals NHS Trust.](https://reader030.fdocuments.in/reader030/viewer/2022032612/56649ec95503460f94bd70eb/html5/thumbnails/8.jpg)
Problems with an IV
bolus
Con
cent
ratio
n
Time
MTC – Minimum Toxic Concentration
24hours
![Page 9: Infusions Mark Tomlin Consultant Pharmacist: Critical Care Southampton University Hospitals NHS Trust.](https://reader030.fdocuments.in/reader030/viewer/2022032612/56649ec95503460f94bd70eb/html5/thumbnails/9.jpg)
Problems with an IV
bolus
Con
cent
ratio
n
Time
MEC – Minimum Effective Concentration
24hours
![Page 10: Infusions Mark Tomlin Consultant Pharmacist: Critical Care Southampton University Hospitals NHS Trust.](https://reader030.fdocuments.in/reader030/viewer/2022032612/56649ec95503460f94bd70eb/html5/thumbnails/10.jpg)
Characteristics of IV therapy
• Half-Life ?
• What Dose ?
• Intermittent Infusion ?
• How Often ?
• With Loading Dose ?
• Continuous Infusion ?
• Effect of organ dysfunction ?
![Page 11: Infusions Mark Tomlin Consultant Pharmacist: Critical Care Southampton University Hospitals NHS Trust.](https://reader030.fdocuments.in/reader030/viewer/2022032612/56649ec95503460f94bd70eb/html5/thumbnails/11.jpg)
An Intermittent
Infusion
Con
cent
ratio
n
Time
MEC – Minimum Effective Concentration
24hours
End Infusion
MTC – Minimum Toxic Concentration
![Page 12: Infusions Mark Tomlin Consultant Pharmacist: Critical Care Southampton University Hospitals NHS Trust.](https://reader030.fdocuments.in/reader030/viewer/2022032612/56649ec95503460f94bd70eb/html5/thumbnails/12.jpg)
Characteristics of IV therapy
• Half-Life ?
• What Dose ?
• Intermittent Infusion ?
• How Often ?
• With Loading Dose ?
• Continuous Infusion ?
• Effect of organ dysfunction ?
![Page 13: Infusions Mark Tomlin Consultant Pharmacist: Critical Care Southampton University Hospitals NHS Trust.](https://reader030.fdocuments.in/reader030/viewer/2022032612/56649ec95503460f94bd70eb/html5/thumbnails/13.jpg)
How often ? – Intermittent bolus
MEC
MTC
2412
![Page 14: Infusions Mark Tomlin Consultant Pharmacist: Critical Care Southampton University Hospitals NHS Trust.](https://reader030.fdocuments.in/reader030/viewer/2022032612/56649ec95503460f94bd70eb/html5/thumbnails/14.jpg)
How often ? – adjacent bolus
MEC
MTC
2412
![Page 15: Infusions Mark Tomlin Consultant Pharmacist: Critical Care Southampton University Hospitals NHS Trust.](https://reader030.fdocuments.in/reader030/viewer/2022032612/56649ec95503460f94bd70eb/html5/thumbnails/15.jpg)
How often ?- accumulating bolus
MTC
MEC
2412
![Page 16: Infusions Mark Tomlin Consultant Pharmacist: Critical Care Southampton University Hospitals NHS Trust.](https://reader030.fdocuments.in/reader030/viewer/2022032612/56649ec95503460f94bd70eb/html5/thumbnails/16.jpg)
Characteristics of IV therapy
• Half-Life ?
• What Dose ?
• Intermittent Infusion ?
• How Often ?
• With Loading Dose ?
• Continuous Infusion ?
• Effect of organ dysfunction ?
![Page 17: Infusions Mark Tomlin Consultant Pharmacist: Critical Care Southampton University Hospitals NHS Trust.](https://reader030.fdocuments.in/reader030/viewer/2022032612/56649ec95503460f94bd70eb/html5/thumbnails/17.jpg)
Accumulating bolus – with Loading Dose or not?
Concentration
Time
MTC
MEC
LD
How long?
![Page 18: Infusions Mark Tomlin Consultant Pharmacist: Critical Care Southampton University Hospitals NHS Trust.](https://reader030.fdocuments.in/reader030/viewer/2022032612/56649ec95503460f94bd70eb/html5/thumbnails/18.jpg)
Characteristics of IV therapy
• Half-Life ?
• What Dose ?
• Intermittent Infusion ?
• How Often ?
• With Loading Dose ?
• Continuous Infusion ?
• Effect of organ dysfunction ?
![Page 19: Infusions Mark Tomlin Consultant Pharmacist: Critical Care Southampton University Hospitals NHS Trust.](https://reader030.fdocuments.in/reader030/viewer/2022032612/56649ec95503460f94bd70eb/html5/thumbnails/19.jpg)
Short Half-life ?Concentration
Time
MTC
MEC
10 mins
![Page 20: Infusions Mark Tomlin Consultant Pharmacist: Critical Care Southampton University Hospitals NHS Trust.](https://reader030.fdocuments.in/reader030/viewer/2022032612/56649ec95503460f94bd70eb/html5/thumbnails/20.jpg)
Short Half-life = InfusionConcentration
Time
MTC
MEC
10 mins
![Page 21: Infusions Mark Tomlin Consultant Pharmacist: Critical Care Southampton University Hospitals NHS Trust.](https://reader030.fdocuments.in/reader030/viewer/2022032612/56649ec95503460f94bd70eb/html5/thumbnails/21.jpg)
Characteristics of IV therapy
• Half-Life ?
• What Dose ?
• Intermittent Infusion ?
• How Often ?
• With Loading Dose ?
• Continuous Infusion ?
• Effect of organ dysfunction ?
![Page 22: Infusions Mark Tomlin Consultant Pharmacist: Critical Care Southampton University Hospitals NHS Trust.](https://reader030.fdocuments.in/reader030/viewer/2022032612/56649ec95503460f94bd70eb/html5/thumbnails/22.jpg)
Reduced elimination
Con
cent
ratio
n
Time
MEC
MTC
![Page 23: Infusions Mark Tomlin Consultant Pharmacist: Critical Care Southampton University Hospitals NHS Trust.](https://reader030.fdocuments.in/reader030/viewer/2022032612/56649ec95503460f94bd70eb/html5/thumbnails/23.jpg)
Reduced elimination
Con
cent
ratio
n
Time
MEC
MTC
![Page 24: Infusions Mark Tomlin Consultant Pharmacist: Critical Care Southampton University Hospitals NHS Trust.](https://reader030.fdocuments.in/reader030/viewer/2022032612/56649ec95503460f94bd70eb/html5/thumbnails/24.jpg)
Extended interval dosing with poor renal perfusion
Concentration
Time