Book contents
- Frontmatter
- Contents
- List of Abbreviations
- Acknowledgements
- Abdominal Trauma: Investigations
- Accessing the Thorax
- Acid-Base
- Acute Renal Failure (see also table in ‘Low urine output’)
- Acute Respiratory Distress Syndrome (ARDS)
- Agitation and Sedation
- Airway Management
- Analgesia
- Aortic Dissection
- Atelectasis
- Blood Pressure Monitoring
- Blood Products
- Blood Transfusion
- Brainstem Death and Organ Donation
- Bronchiectasis
- Burns
- Calcium Balance
- Cardiac Assessment
- Cardiogenic Shock
- Central Line Insertion
- Chronic Renal Failure
- Coagulation Defects
- Disseminated Intravascular Coagulation (DIC)
- ECG I – Basic Concepts
- ECG II – Rate and Rhythm Disturbances
- Endotracheal Intubation
- Enteral Nutrition
- Extubation and Weaning
- Fat Embolism Syndrome
- Flail Chest
- Fluid Therapy
- Haemorrhagic Shock
- Head Injury I – Physiology
- Head Injury II – Pathophysiology
- Head Injury III – Principles of Management
- Inotropes and Circulatory Support
- ITU Admission Criteria
- Jugular Venous Pulse (JVP)
- Lactic Acidosis
- Low Urine Output State
- Magnesium Balance
- Mechanical Ventilatory Support
- Metabolic Acidosis (see also ‘Acid-base’ and and ‘Lactic acidosis’)
- Metabolic Alkalosis
- Nutrition: Basic Concepts (see also parenteral nutrition & TPN)
- Oxygen: Basic Physiology
- Oxygen Therapy
- Parenteral Nutrition (TPN)
- Pneumonia
- Pneumothorax
- Potassium Balance
- Pulmonary Artery Catheter (see also ‘Central line insertion’)
- Pulmonary Thromboembolism
- Pulse Oximetry
- Renal Replacement Therapy
- Respiratory Assessment
- Respiratory Failure (see also ‘Oxygen therapy’)
- Rhabdomyolysis
- Septic Shock and Multi-Organ Failure
- Sodium and Water Balance
- Spinal Injury
- Systemic Response to Trauma
- Tracheostomy
- Transfer of the Critically Ill
- Tube Thoracostomy (Chest Drain)
Magnesium Balance
- Frontmatter
- Contents
- List of Abbreviations
- Acknowledgements
- Abdominal Trauma: Investigations
- Accessing the Thorax
- Acid-Base
- Acute Renal Failure (see also table in ‘Low urine output’)
- Acute Respiratory Distress Syndrome (ARDS)
- Agitation and Sedation
- Airway Management
- Analgesia
- Aortic Dissection
- Atelectasis
- Blood Pressure Monitoring
- Blood Products
- Blood Transfusion
- Brainstem Death and Organ Donation
- Bronchiectasis
- Burns
- Calcium Balance
- Cardiac Assessment
- Cardiogenic Shock
- Central Line Insertion
- Chronic Renal Failure
- Coagulation Defects
- Disseminated Intravascular Coagulation (DIC)
- ECG I – Basic Concepts
- ECG II – Rate and Rhythm Disturbances
- Endotracheal Intubation
- Enteral Nutrition
- Extubation and Weaning
- Fat Embolism Syndrome
- Flail Chest
- Fluid Therapy
- Haemorrhagic Shock
- Head Injury I – Physiology
- Head Injury II – Pathophysiology
- Head Injury III – Principles of Management
- Inotropes and Circulatory Support
- ITU Admission Criteria
- Jugular Venous Pulse (JVP)
- Lactic Acidosis
- Low Urine Output State
- Magnesium Balance
- Mechanical Ventilatory Support
- Metabolic Acidosis (see also ‘Acid-base’ and and ‘Lactic acidosis’)
- Metabolic Alkalosis
- Nutrition: Basic Concepts (see also parenteral nutrition & TPN)
- Oxygen: Basic Physiology
- Oxygen Therapy
- Parenteral Nutrition (TPN)
- Pneumonia
- Pneumothorax
- Potassium Balance
- Pulmonary Artery Catheter (see also ‘Central line insertion’)
- Pulmonary Thromboembolism
- Pulse Oximetry
- Renal Replacement Therapy
- Respiratory Assessment
- Respiratory Failure (see also ‘Oxygen therapy’)
- Rhabdomyolysis
- Septic Shock and Multi-Organ Failure
- Sodium and Water Balance
- Spinal Injury
- Systemic Response to Trauma
- Tracheostomy
- Transfer of the Critically Ill
- Tube Thoracostomy (Chest Drain)
Summary
What is the normal serum level of magnesium?
0.7–1.0 mmol/L.
What is the distribution of magnesium in the body?
Magnesium is the second most abundant intracellular cation after potassium. The total body magnesium is ∼25 g, with 65% being located in the bone. Only 1% of the body magnesium is found in the serum, so that the serum level is a poor ref lection of the total body store.
What purpose does magnesium serve?
Magnesium is an essential co-factor in a number of enzymes, notably in the transfer of phosphate groups, and protein synthesis. It is most conspicuously important for the normal function of the central nervous, neuromuscular and cardiovascular systems.
What is the relationship between magnesium and serum calcium?
High magnesium levels prevent calcium cellular uptake, and for this reason, hypermagnesaemia can lead to bradycardia and sluggish deep tendon ref lexes. What drug is used to reverse the effects of severe hypermagnesaemia? Calcium gluconate.
Which organ is largely responsible for magnesium homeostasis?
The kidney is the major site for magnesium balance. It is freely filtered at the glomerulus, and reabsorbed mainly at the proximal convoluted tubule and thick ascending limb of Henle.
What are the main causes of hypomagnesaemia?
Renal losses: any state of excess diuresis, e.g. diuretic use, diuretic phase of acute renal failure, hypercalcemia
Alcoholism
Gut losses/malabsorption: diarrhoea, inflammatory bowel disease, malnutrition, intestinal resection and bypasses
Endocrine disturbance: diabetes mellitus, hyperparathyroidism, hyperthyroidism
How common is hypomagnesaemia in the hospital setting?
Hypomagnesaemia occurs in over 60% of the critically ill, most commonly associated with the use of diuretics.
- Type
- Chapter
- Information
- Surgical Critical Care Vivas , pp. 151 - 152Publisher: Cambridge University PressPrint publication year: 2002