What does Lactated Ringer (LR) contain?
Calcium and potassium that approximate plasma concentration
What is the purpose of lactate in Lactated Ringer?
To buffer metabolic acidosis
Why is Lactated Ringer unsuitable for patients with end-stage liver disease?
Lactate requires metabolism in the liver to CO2 & water
What may be a better alternative to Lactated Ringer in major hepatectomy?
Plasma-lyte
What is contraindicated when using Lactated Ringer?
As a diluent for blood transfusions
Why can’t Lactated Ringer be used as a diluent for blood transfusions?
Calcium binds to the citrate anticoagulant in blood products
What is the volume of 1 unit of Red Blood Cells (RBC)?
1 unit ≈ 300 mL: 180 mL RBC, 130 mL storage solution (Hct ≈ 55%); ↑ pt’s Hct 3%/unit
When is transfusion generally not required for patients without active bleeding or ongoing cardiac ischemia?
Transfusion generally not required at Hct’s >21%.
(The TRICC Study, NEJM 1999;340:409–417)
What is Fenoldopam (Corlopam) indicated for?
Short-term management (<48 h) of severe hypertension
Fenoldopam is used for quick control of high blood pressure in critical situations.
What is the infusion preparation for Fenoldopam?
10 mg in 250 mL = 40 mcg/mL
This concentration is used for intravenous administration.
What is the dosage range for Fenoldopam infusion?
0.1–1.6 mcg/kg/min
Dosage should be titrated every 15 minutes.
How should Fenoldopam be administered?
Infusion only; do not bolus
Bolus administration is not recommended due to potential adverse effects.
What is the mechanism of action of Fenoldopam?
Dopamine (D1) receptor agonist causing rapid vasodilation
It affects coronary, renal, mesenteric, and peripheral arteries.
True or False: Fenoldopam can be used for long-term management of hypertension.
False
It is indicated only for short-term management (<48 hours).
What is the primary indication for Dobutamine (Dobutrex)?
Heart failure
Dobutamine is primarily used to treat heart failure.
What is the adult dosage range for Dobutamine infusion?
2 mcg/kg/min, titrate 2–20 mcg/kg/min, max 40 mcg/kg/min
The infusion starts at 2 mcg/kg/min and can be titrated based on patient response.
What is the pediatric dosage range for Dobutamine?
5–20 mcg/kg/min
Pediatric dosing is typically higher than adult minimum dosing.
What is the onset time for Dobutamine?
12 min
The onset of action for Dobutamine is relatively quick.
What is the duration of effect for Dobutamine?
<10 min
The effects of Dobutamine are short-lived, requiring continuous infusion.
What is the predominant mechanism of action for Dobutamine?
Predominantly β1-adrenergic agonist
This mechanism primarily affects the heart, increasing contractility.
How is Dobutamine cleared from the body?
Hepatic metabolism, renal excretion
The drug is metabolized by the liver and excreted by the kidneys.
What effect does Dobutamine have on systemic vascular resistance (SVR)?
↓ SVR especially at lower doses
At lower doses, Dobutamine can reduce systemic vascular resistance.
What factors influence the blood pressure effect of Dobutamine?
Preload (volume status) and the presence of ‘recruitable’ inotropy
Blood pressure response is closely linked to the patient’s volume status.
In what clinical situations is Dobutamine useful?
- Cardiogenic shock
- Sepsis-induced myocardial dysfunction
Dobutamine is particularly valuable in acute heart failure scenarios.
