Calcium Gluconate 10% — 10 ml IV over 2–5 min Membrane stabilisation. Onset 1–3 min. Duration 30–60 min. Does NOT lower K⁺. Repeat if ECG changes persist. Avoid in digoxin toxicity.
Insulin + Dextrose — Actrapid 10 units IV + 50 ml 50% dextrose Drives K into cells. Lowers K by 0.5–1.5 mmol/L. Onset 15–30 min. Monitor BGL hourly ×6.
Salbutamol 10–20 mg nebulised Beta-2 agonist drives K intracellularly. Additional 0.5 mmol/L reduction. Causes tachycardia — avoid in ACS.
Sodium Bicarbonate 8.4% — 50 ml IV (if metabolic acidosis present) Correcting acidosis helps shift K. Less effective than insulin in isolation.
Cation exchangers — Calcium Resonium 15–30 g PO/PR or Patiromer 8.4 g PO Remove K from body (GI tract). Onset 4–6 h. For ongoing management.
Dialysis (Haemodialysis) Definitive removal. Required for severe/refractory hyperkalaemia, especially with oliguria/anuria.
ℹ
Always repeat K⁺ from a fresh, atraumatic sample before treating if asymptomatic and ECG normal — pseudohyperkalaemia is common with haemolysed samples. Confirm with blood gas K if urgent.
▼ Hypocalcaemia (Ca <2.2 mmol/L)
Clinical Signs
Chvostek sign: tap facial nerve anterior to ear → ipsilateral facial twitch
Trousseau sign: inflate BP cuff 20 mmHg above systolic ×3 min → carpal spasm (more specific)
Hypoparathyroidism (post-thyroidectomy)Vitamin D deficiency (very common in GCC)Acute pancreatitisMassive transfusion (citrate binds Ca)HypomagnesaemiaRenal failure (phosphate retention)Malabsorption (Crohn's, coeliac)Bisphosphonates/denosumab
⚠
Albumin correction: Corrected Ca = Measured Ca + 0.02 × (40 − Albumin g/L). Always correct for albumin before treating. Use ionised Ca if critically ill.
Treatment
Acute/Symptomatic: Calcium gluconate 10% — 10 ml (2.25 mmol Ca) IV over 10 min, followed by infusion 10 mmol over 4–6 h
Preferred over calcium chloride in peripheral lines (less irritant)
Calcium chloride 10% (6.8 mmol/10ml): reserved for cardiac arrest / central line
Magnesium glycinate or citrate — better GI tolerance
▲ Hypermagnesaemia (Mg >1.0 mmol/L)
Causes
Eclampsia treatment (IV MgSO₄ infusion) — most common in GCC hospitals
Renal failure (impaired Mg excretion) — major risk factor
Excessive antacid/laxative use (Mg-containing)
Enema misuse
Toxicity Levels
Mg Level
Effect
1.5 – 2.5 mmol/L
Nausea, flushing, hypotension, bradycardia
2.5 – 5.0 mmol/L
ECG changes (PR prolongation, QRS widening)
>5.0 mmol/L
Loss of deep tendon reflexes (patella reflex)
>7.5 mmol/L
Respiratory muscle paralysis
>12 mmol/L
Cardiac arrest
Treatment
Stop Mg infusion immediately
IV Calcium Gluconate 10% 10–20 ml — directly antagonises Mg at membrane level (antidote)
IV fluids + furosemide — promote renal excretion
Haemodialysis — if severe or anuric
Respiratory support if ventilatory failure
🚨
During MgSO₄ eclampsia infusion: monitor reflexes hourly, RR every 15 min, urine output. Have calcium gluconate at bedside. Hold if reflexes absent.
▹ Crystalloids Comparison
Fluid
Na mmol/L
K mmol/L
Cl mmol/L
Ca/Lactate
Tonicity
Key Uses / Notes
0.9% NaCl (Normal Saline)
154
0
154
—
Isotonic
Resuscitation, hyponatraemia correction, drug dilution. Hyperchloraemic metabolic acidosis risk with large volumes (>2L)
Hartmann's / Lactated Ringer's
131
5
111
Lactate 29 / Ca 2
Isotonic
Balanced, physiological. Preferred for large-volume resuscitation. Avoid in head injury (slightly hypotonic vs plasma). Lactate metabolised to HCO₃
PlasmaLyte 148
140
5
98
Acetate 27
Isotonic
Most balanced crystalloid. Acetate metabolised to HCO₃. Good for high-volume surgery, burns.
5% Glucose (Dextrose)
0
0
0
—
Isotonic in bag → hypotonic in body
Free water replacement (hypernatraemia), hypoglycaemia. Not for resuscitation — does not stay intravascular.
5% Glucose + 0.45% NaCl
77
0
77
—
Hypotonic
Maintenance fluids (paediatrics, adults post-op). Must not use for resuscitation. Hyponatraemia risk.
0.45% NaCl (Half Normal)
77
0
77
—
Hypotonic
Free water + Na replacement. Hypernatraemia correction when some Na needed.
8.4% Sodium Bicarbonate
1000
0
0
HCO₃ 1000
Hypertonic
Severe metabolic acidosis (pH <7.1), hyperkalaemia (adjunct), TCA overdose. Central line preferred.
3% NaCl (Hypertonic Saline)
513
0
513
—
Hypertonic
Severe symptomatic hyponatraemia, raised ICP. ICU only. Strict rate monitoring.
▹ Colloids
Human Albumin Solutions
4% Albumin (Isooncotic): Large-volume paracentesis replacement (6–8 g per litre of ascites drained). Post-SBP spontaneous bacterial peritonitis treatment.
20% Albumin (Hyperoncotic): Severe hypoalbuminaemia (<20 g/L) with oedema, hepatorenal syndrome, diuretic-resistant nephrotic syndrome.
No proven mortality benefit over crystalloids in general ICU patients (SAFE trial)
Voluven (HES 130/0.4): Similar short-term volume expansion.
⚠
AVOID hydroxyethyl starch (HES) in sepsis — increased AKI risk and mortality (CHEST/6S trials). Contraindicated in critical illness, renal impairment, coagulopathy. Restricted in EU/UK/GCC guidelines.
▹ Maintenance Fluid Calculation — 4-2-1 Rule
Holliday-Segar Method (4-2-1 Rule)
First 10 kg: 4 ml/kg/h
Next 10 kg: 2 ml/kg/h
Each remaining kg: 1 ml/kg/h
Weight
Daily fluid (ml/day)
Hourly rate
10 kg
1,000
40 ml/h
20 kg
1,500
60 ml/h
40 kg
1,700
70 ml/h
70 kg
2,500
104 ml/h (approx)
80 kg
2,600
108 ml/h (approx)
ℹ
Adjust for fever (+10–15% per °C above 37.5), Burns, high-output fistulas. Reduce in CCF, AKI, hyponatraemia risk. Post-op patients often need less.
▹ Fluid Challenge Protocol
Standard Challenge
Volume: 250–500 ml crystalloid (Hartmann's preferred)
Rate: Over 15–30 minutes
Assess response at 15 and 30 min
Response Markers
MAP rise ≥10 mmHg
HR reduction ≥10 bpm
Stroke volume (SV) / Cardiac Output (CO) increase ≥10% by echo or LiDCO
UO improvement (if oliguria was indication)
Stop Challenge If
CVP rises >5 mmHg without CO improvement
New pulmonary oedema / crackles
SpO₂ drops
Fluid overload signs (LL oedema, raised JVP)
⚠
Fluid Stewardship: GCC hospitals adopting NICE IV fluid audit standards. Reassess fluid status every 4h in ward patients. Identify and document fluid indication (resuscitation / routine maintenance / replacement / nutritional).
▹ IV Fluid in TPN (GCC ICU Nutrition Protocols)
TPN electrolyte requirements: Na 1–2 mmol/kg/day, K 0.7–1.0 mmol/kg/day, Mg 0.1–0.2 mmol/kg/day, PO₄ 0.3–0.5 mmol/kg/day
Refeeding syndrome risk: Hypophosphataemia within 72h of restarting nutrition in malnourished patients. Monitor PO₄, K, Mg daily for first week.
Thiamine 200–300 mg IV before TPN if at risk of refeeding syndrome
Daily U&E, LFTs, glucose, phosphate, Mg, Ca during TPN initiation
GCC hospitals: pharmacist-led TPN bag preparation in aseptic pharmacy units
☀ Heat-Related Electrolyte Losses (GCC Summer)
GCC summer temperatures exceed 45°C. Occupational heat exposure (construction workers, outdoor laborers) and exercise-induced sweating cause significant electrolyte disturbance.
Sweat Composition (per litre)
Electrolyte
Sweat Concentration
Clinical Impact
Sodium
20–80 mmol/L
Hyponatraemia with excessive hypotonic fluid replacement
Potassium
4–8 mmol/L
Mild hypokalaemia (less significant)
Chloride
20–60 mmol/L
Hypochloraemic alkalosis (rare with oral replacement)
Key Clinical Scenarios
Exertional hyponatraemia: athletes/workers drinking large volumes plain water → dilutional → can be severe and acute
Heat stroke: combined hypernatraemia (free water loss > electrolyte loss), rhabdomyolysis, AKI → hyperkalaemia
Oral Rehydration Salts (ORS): WHO formula preferred for field replacement
Ramadan fasting (12–17h in GCC summer) creates specific electrolyte risks in patients with chronic disease. All GCC nurses should be familiar with these scenarios.
High-Risk Scenarios
⚠
K-sparing diuretics + 12h fluid fast → Hyperkalaemia risk. K accumulates without urinary excretion window. Spironolactone/amiloride may need dose adjustment or temporary pause.
⚠
Loop diuretics + no fluid intake + heat → Dehydration + Hyponatraemia. Diuretics taken at Iftar on empty stomach with poor fluid intake → intravascular depletion + hyponatraemia.
Monitoring Recommendations
Pre-Ramadan U&E, Mg, and Ca baseline for patients on diuretics, ACEi, ARBs
Repeat U&E at 2 weeks if on K-altering medications
Advise adequate hydration between Iftar and Suhoor (9 PM–3 AM window)
DM patients: DKA risk during fasting — check BGL and K monitoring protocols
Counsel patients on warning symptoms: muscle cramps, palpitations, dizziness
▲ High DKA Rate & Hypokalaemia (GCC)
GCC countries have among the world's highest rates of Type 2 Diabetes Mellitus. DKA presentations are frequent, often with severe hypokalaemia on correction.
DKA K⁺ Dynamics
Initial K⁺ may appear normal/high (acidosis pushes K extracellularly)
Total body K is depleted from osmotic diuresis and vomiting
Insulin therapy + fluid resuscitation rapidly drops serum K
Severe hypokalaemia can cause fatal arrhythmia if insulin started without K replacement
🚨
DKA Protocol: Do NOT start insulin if K <3.5 mmol/L. Replace K first. If K 3.5–5.0: add 40 mmol KCl per litre. If K >5.5: insulin only, recheck K in 1h.
GCC DKA Monitoring Frequency
Parameter
Frequency
Blood glucose
Hourly (BGL)
K⁺, Na⁺, HCO₃⁻
Every 2 h for first 6h, then 4-hourly
Blood gas (pH)
2-hourly until pH >7.3
Ketones (blood)
Every 2h (target <0.6 mmol/L)
△ Eclampsia & Mg Toxicity Risk (GCC)
MgSO₄ is used for eclampsia seizure prophylaxis in GCC. Renal impairment is a significant risk factor for Mg toxicity accumulation.
MgSO₄ Eclampsia Protocol
Loading dose: 4–6 g IV over 15–20 min
Maintenance: 1–2 g/h IV infusion
Duration: 24–48 h post-delivery or post-last seizure
Mandatory Monitoring (every 4h)
Urine output: must be >25–30 ml/h (withhold if anuric)
Patellar reflexes: must be present (loss indicates >5 mmol/L)
Respiratory rate: must be >12/min
Serum Mg: target therapeutic 2–3.5 mmol/L
⚠
Always keep calcium gluconate 10% 10 ml at bedside during MgSO₄ infusion. Antidote for Mg toxicity. Give IV over 3 min for respiratory arrest.
📋 GCC Laboratory Turnaround Times
Test
POC (Bedside)
Central Lab (Urgent)
Central Lab (Routine)
Na, K, Cl, HCO₃
2–5 min (ABG/VBG)
30–60 min
2–4 h
Blood gas K⁺
2–5 min (highly accurate)
—
—
Mg, Ca, PO₄
Not available POC
1–2 h
4–8 h
Ionised Ca
2–5 min (ABG analyser)
1 h
4 h
Urine Na/K/osmolality
Not available
2–4 h
8–24 h
ℹ
For critical hyperkalaemia or hyponatraemia: use blood gas K⁺/Na⁺ for immediate management while awaiting formal labs. Confirm haemolysis absence on blood gas sample.
⚙ IV Fluid Stewardship — GCC Programme
GCC hospitals adopting NICE IV Fluid Audit standards (NICE CG174 adapted for GCC climate)
IV fluid prescriptions require: indication, volume, rate, and electrolyte monitoring plan
Nursing checklist: Is IV fluid still indicated? Can oral hydration replace?
Post-op patients: switch to oral as soon as bowel sounds return and nausea resolved
IV fluid waste reduction: unused bags returned to pharmacy, QI metric in MOH audits
GCC-Specific Considerations
Vitamin D deficiency: Extremely prevalent across GCC (limited sunlight exposure, covered clothing, dark skin). Check 25-OH Vitamin D in all hypocalcaemia workups.
Hypophosphataemia: Common in malnourished migrant worker population, post-bariatric surgery patients (high rates in GCC).
Diuretic-induced electrolyte imbalance: High HTN prevalence → high diuretic use → frequent hypokalaemia, hyponatraemia in outpatient clinics.
📚 Practice MCQs — Electrolyte & Fluid Management
Q1.A patient with chronic SIADH has a Na⁺ of 114 mmol/L and is drowsy but not seizing. Over what period should Na be corrected to 122 mmol/L to avoid osmotic demyelination syndrome?
Chronic hyponatraemia (>48h or unknown onset): max correction 8–10 mmol/L in 24h. Rapid correction causes osmotic demyelination syndrome (ODS), previously called central pontine myelinolysis — irreversible. 8 mmol/L correction over 24h is appropriate here.
Q2.A nurse is preparing to give IV potassium to a patient with K⁺ of 2.8 mmol/L via a peripheral IV. What is the maximum safe infusion rate?
Peripheral IV: maximum 10–20 mmol/h in a solution of max 40 mmol/L. Central line: up to 40 mmol/h with continuous cardiac monitoring. NEVER give undiluted IV potassium push — causes immediate cardiac arrest.
Q3.A patient with severe hyperkalaemia (K⁺ 7.2 mmol/L) has a sine-wave ECG pattern. What is the FIRST priority treatment?
Calcium gluconate is the first step — it provides immediate cardiac membrane stabilisation. It does NOT lower serum K but protects the heart while other treatments work. Essential with any ECG changes (peaked T, PR prolongation, wide QRS, sine wave). Then follow with insulin/dextrose, salbutamol, etc.
Q4.During an eclampsia MgSO₄ infusion, the nurse notices the patient has absent patellar reflexes and a respiratory rate of 10/min. What action is CORRECT?
Absent reflexes indicate Mg >5 mmol/L (toxic). RR <12/min suggests impending respiratory arrest (Mg >7.5). Stop infusion immediately and give calcium gluconate (the antidote). Respiratory support may also be needed. These monitoring parameters must be checked every hour during Mg infusion.
Q5.A 58-year-old with cirrhosis has Na⁺ of 128, urine Na⁺ <10 mmol/L, urine osmolality 600 mOsm/kg, and ascites. What is the most likely diagnosis and treatment?
Urine Na <20 mmol/L indicates extra-renal Na avidity (kidneys holding Na). Combined with ascites and cirrhosis, this is hypervolaemic hyponatraemia from portal hypertension and RAAS activation. SIADH would have urine Na >40. Treatment: fluid restriction, treat cirrhosis, spironolactone ± furosemide, tolvaptan in refractory cases.
Q6.Which IV fluid is MOST appropriate for large-volume surgical resuscitation, and why?
Hartmann's/Lactated Ringer's is the preferred balanced crystalloid for large-volume resuscitation. Normal saline causes hyperchloraemic metabolic acidosis with volumes >2L (Cl 154 mmol/L vs plasma 100 mmol/L). 5% glucose does not stay intravascular. 20% albumin is not used for routine surgical resuscitation.
Q7.A patient with refractory hypokalaemia (K⁺ 2.9) despite repeated IV replacement is found to have a Mg²⁺ of 0.45 mmol/L. What is the most important next step?
Hypomagnesaemia causes refractory hypokalaemia by increasing renal K wasting (Mg is required for proper K channel function in the loop of Henle). Until Mg is corrected, potassium supplementation will be ineffective. Always check and correct Mg in persistent hypokalaemia.
Q8.A DKA patient has initial K⁺ of 3.2 mmol/L. Blood glucose is 28 mmol/L. What should happen BEFORE insulin is started?
DKA protocol: Do NOT start insulin if K <3.5 mmol/L. Insulin drives K into cells, causing a further drop that can be fatal (arrhythmia). Replace K first to reach >3.5 mmol/L. Despite a high/normal initial K (due to acidosis), total body K is depleted. Close monitoring every 2h throughout DKA treatment.
Q9.A post-thyroidectomy patient on Day 2 develops perioral tingling, muscle cramps, and a positive Trousseau sign. Which ECG change would you expect?
Post-thyroidectomy hypocalcaemia (parathyroid glands inadvertently removed or damaged). Hypocalcaemia causes prolonged QTc (increased action potential duration). Chvostek and Trousseau signs confirm tetany. Treat with IV calcium gluconate 10% 10ml over 10 min then infusion. Shortened QTc is seen in hypercalcaemia.
Q10.A Ramadan-fasting patient on spironolactone for CCF presents with weakness and palpitations. K⁺ is 6.2 mmol/L. ECG shows peaked T waves. First-line nursing action?
ECG changes with K 6.2 = medical emergency. Nursing priorities: continuous cardiac monitoring, urgent medical review, prepare calcium gluconate 10% (membrane stabilisation), insulin/dextrose (K-lowering), and hold spironolactone. This is the GCC Ramadan risk: K-sparing diuretic + reduced urinary K excretion window + 12h fast = hyperkalaemia. Never delay with cardiac ECG changes.