QuestionQA
Concept
Chapter
#### Monitoring

The BNF advises to monitor lung function (in patients with a history of obstructive airway disease).

#### Overdoses

Overdosages with beta-blockers may cause cardiac effects such as bradycardia, hypotension, syncope, conduction abnormalities, and heart failure. Bradycardia is the most common arrhythmia, but some beta-blockers may induce ventricular tachyarrhythmias secondary to prolongation of QT interval (e.g. sotalol) or QRS duration (e.g. propranolol).
Non-cardiovascular effects include central nervous system effects (including drowsiness, confusion, convulsions, hallucinations, and in severe cases coma), respiratory depression, and bronchospasm.

Management
 - Airway protection 
 - Activated charcoal within 1 hour
 - IV Fluids
 
IV glucagon is the first-line management.
 
For symptomatic bradycardia, IV atropine may be used.

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Calculation of infusion rate
Topic
13
Neurosurgery
A concentration of 20% is 20kg in 100L = 20mg in 0.1mL = 200mg in 1mL. Since the patient requires 10g of magnesium sulphate, the minimum volume of 0.9% sodium chloride is: 10g ÷ 200mg/mL = 50mL.

Concentration ratios (20% in this case) are based on units of kilogram and litre as they belong to the International System of Units (SI units) which are used by convention.
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QuestionQAAnswer
50
mL
A 38-year-old patient suffers from hypomagnesaemia. She is prescribed a magnesium sulphate infusion of 10g once-daily for five days in a 0.9% sodium chloride solution. The concentration of magnesium sulphate should not exceed 20%.


What is the minimum volume of 0.9% sodium chloride required to safely make up the magnesium sulphate solution?