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Anaesthesia Considerations in Special Populations

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DEFINITIONS

• Neonate: 0-28 days
• Infant: 1-12 months
• Toddler: 1-3 years
• Preschool: 3-5 years
• School age: 6-12 years
• Adolescent: 13-18 years

• Young-old: 65-74 years
• Old: 75-84 years
• Oldest-old (frail elderly): >85 years

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PART 1: NEONATAL ANAESTHESIA CONSIDERATIONS

Physiological Basis (Why Neonates Are Different)

Cardiovascular System

• Fetal circulation (patent foramen ovale, patent ductus arteriosus) closes after birth; any stress (hypoxia, acidosis, hypothermia) can cause persistent pulmonary hypertension of the newborn (PPHN) - a reversal back to fetal-type circulation with right-to-left shunting
• Stroke volume is relatively fixed in the immature, noncompliant left ventricle - cardiac output is therefore heart-rate dependent
• Both ventricles are interdependent; failure of one often precipitates biventricular failure
• Normal neonatal heart rate: 120-160 bpm; bradycardia is poorly tolerated

Respiratory System

• Fewer and smaller alveoli - reduced lung compliance
• Cartilaginous rib cage - highly compliant chest wall, paradoxical movement
• Increased airway resistance and increased work of breathing
• Respiratory muscles fatigue easily - prone to apnea
• Decreased functional residual capacity (FRC) - rapid O2 desaturation during apnea/intubation attempts
• High oxygen consumption (6-8 mL/kg/min vs 3-4 mL/kg/min in adults)
• High minute ventilation-to-FRC ratio - rapid rise in alveolar anesthetic concentration, speeds inhalation induction

Airway Anatomy (Compared to Adults)

• Larger head and occiput - causes neck flexion when supine; shoulder roll needed
• Larger tongue relative to oral cavity
• Obligate nasal breathers until ~5 months
• Larynx: anterior, cephalad (at C3-4 vs C5-6 in adults), with anteriorly slanted vocal folds - "anterior" airway
• Longer, floppy U-shaped epiglottis - straight blade (Miller) preferred
• Narrowest point at cricoid ring (subglottis) in children <5 years, unlike adults where it is at the glottis - ETT fit is assessed by leak
• Shorter trachea (~4 cm) - risk of right main stem intubation

Hepatic & Renal Systems

• Immature hepatic enzyme systems (CYP450) - delayed drug metabolism
• Reduced plasma protein binding (lower albumin, alpha-1-acid glycoprotein) - increased free drug fraction
• Glomerular filtration rate (GFR) low at birth, reaches adult values by 6-12 months
• Prolonged drug elimination - risk of accumulation

Thermoregulation

• Thin skin, low subcutaneous fat, large body surface area-to-weight ratio
• Cannot shiver - depend on non-shivering thermogenesis via brown adipose tissue (BAT)
• Hypothermia causes: delayed awakening, arrhythmias, respiratory depression, increased pulmonary vascular resistance, increased anesthetic sensitivity

Drug Pharmacology

• MAC values: Neonatal MAC for most volatiles is lower than infants (immature CNS)
• MAC for sevoflurane - no increase from neonates to infants (unlike halothane)
• Sevoflurane is the agent of choice for inhalation induction in neonates/pediatrics
• Increased volume of distribution for water-soluble drugs (higher total body water - 75-80% in neonates vs 60% in adults)

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A. PREOPERATIVE CONSIDERATIONS - NEONATE

1. Patient Assessment

• Gestational age and postnatal age - critical for risk stratification
• Corrected age = gestational age + postnatal age; premature neonates assessed by corrected age
• Weight - all drug doses, ETT sizes, fluid calculations are weight-based
• Review birth history: APGAR scores, NICU admission, respiratory support, surfactant use
• Associated congenital anomalies (VACTERL, chromosomal syndromes)
• Current medications and NPO (nil per os) status

2. NPO (Fasting) Guidelines - Neonates

• Neonates are especially vulnerable to hypoglycemia during prolonged fasting - monitor blood glucose

3. Investigations

• Blood glucose (mandatory - risk of hypoglycemia)
• Hemoglobin / hematocrit (neonatal Hb is 14-20 g/dL; fetal Hb has higher O2 affinity)
• Serum electrolytes, calcium
• Echocardiography if cardiac anomaly suspected
• Chest X-ray for respiratory conditions

4. Stabilization Before Surgery

• Correct metabolic disturbances (hypoglycemia, metabolic acidosis, electrolyte abnormalities)
• Establish IV access - peripheral IV or intraosseous (IO) if needed
• Dextrose-containing maintenance fluids (D10W for neonates) to prevent hypoglycemia
• Temperature stabilization (warm environment, warmed blankets)
• True surgical emergencies in neonates are uncommon; adequate preoperative stabilization cannot be overemphasized (e.g., TEF, omphalocele, CDH)

5. Premedication

• Atropine (0.02 mg/kg IV/IM, minimum 0.1 mg): recommended to prevent vagally-mediated bradycardia (neonates are particularly prone)
• Sedative premedication generally avoided in neonates due to respiratory depression risk
• Topical anesthetics (EMLA, LMX-4) for IV placement (allow adequate time)

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B. INTRAOPERATIVE CONSIDERATIONS - NEONATE

1. Monitoring

• Standard ASA monitors: ECG, SpO2, NIBP, ETCO2, temperature
• Pre- and post-ductal SpO2 monitoring in neonates with suspected cardiac disease or PPHN
• Temperature monitoring (rectal, esophageal, or axillary) - mandatory
• Arterial line for major cases, blood glucose monitoring
• Urine output monitoring (Foley catheter for prolonged cases)

2. Airway Management

• Shoulder roll to extend neck and align airway axes
• Straight laryngoscope blade (Miller 0 or 1) preferred for anterior neonatal larynx
• Uncuffed ETT for neonates and children <8 years (cuffed may be used with low cuff pressures <20 cmH2O)
• ETT size: Age/4 + 4 formula (for cuffed); depth = weight (kg) + 6 cm at lip for neonates
• ETT leak test: positive (air leak at 15-25 cmH2O) confirms appropriate size at cricoid
• Confirm position with bilateral auscultation and CXR (short trachea - right main stem intubation risk)

3. Maintenance of Anaesthesia

• Sevoflurane (inhalation agent of choice) - non-pungent, rapid induction, cardiovascular stability
• Total IV anaesthesia (TIVA) - propofol (use cautiously due to PRIS risk in neonates/infants), ketamine, or dexmedetomidine
• Nitrous oxide - used cautiously; avoid in bowel obstruction, pneumothorax, or when high FiO2 required
• Opioids: morphine, fentanyl, remifentanil (infusion) - doses reduced; monitor for respiratory depression
• Neuromuscular blocking agents: succinylcholine (for RSI; risk of hyperkalemia with undiagnosed myopathies), rocuronium (intubation), atracurium or cisatracurium (maintenance - Hofmann elimination, safe in hepatic/renal immaturity)
• Neostigmine + atropine/glycopyrrolate for reversal; sugammadex used for rocuronium reversal

4. Ventilation

• Controlled mechanical ventilation for most neonatal procedures
• Tidal volume: 6-8 mL/kg; peak inspiratory pressure (PIP) <25 cmH2O to avoid barotrauma
• PEEP 3-5 cmH2O
• Use of air-oxygen blends to titrate SpO2 (target 95-99%); avoid hyperoxia (retinopathy of prematurity risk)

5. Fluid Management

• Maintenance: 4 mL/kg/hr for first 10 kg (4-2-1 rule)
• Use isotonic crystalloids (normal saline or Plasmalyte) for replacement
• Dextrose-containing fluids for maintenance to prevent hypoglycemia
• Allowable blood loss (ABL) = EBV × (starting Hct - acceptable Hct) / starting Hct
• Estimated blood volume (EBV): 85-90 mL/kg in neonates; 80 mL/kg in infants
• Transfuse when Hb <10 g/dL in neonates (higher threshold due to higher O2 demand)
• Warm all IV fluids and blood products

6. Temperature Management

• Warm the operating room (26-28°C) before patient arrival
• Forced-air warming blanket (Bair Hugger)
• Warm IV fluids and blood products
• Humidification of inspired gases
• Radiant warmers on transport
• Target temperature: 36.5-37.5°C

7. Special Intraoperative Considerations

• PPHN management: avoid hypoxia, hypercarbia, acidosis, hypothermia (all precipitate pulmonary vasoconstriction); iNO (inhaled nitric oxide) if needed
• Retinopathy of prematurity (ROP): titrate FiO2 to keep SpO2 95-99% (avoid SpO2 >99% in premature neonates <44 weeks corrected age)
• Neurodevelopmental concerns: accumulating evidence for potential neurotoxicity of volatile agents and ketamine in developing brain (FDA warning); minimize exposure, consider regional techniques

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C. POSTOPERATIVE CONSIDERATIONS - NEONATE

1. Extubation

• Extubate when fully awake, strong cry, adequate respiratory effort
• Premature neonates (<60 weeks postconceptional age): higher risk of postoperative apnea - consider remaining intubated overnight or monitoring with apnea monitor for at least 12 hours postoperatively

2. Postoperative Apnea

• Risk factors: prematurity, anemia, intraoperative opioids
• Premature neonates (<44 weeks corrected age): caffeine IV (loading 20 mg/kg, then 5-10 mg/kg) to stimulate respiratory drive
• All premature neonates (<60 weeks PCA) should receive 12-24 hours of apnea monitoring after general anaesthesia

3. Pain Management

• Multimodal analgesia: IV opioids (morphine 0.05-0.1 mg/kg; fentanyl 1-2 mcg/kg) with careful monitoring
• Paracetamol (acetaminophen) IV: 7.5-10 mg/kg Q8h in preterm neonates; 10-15 mg/kg Q6h in term neonates
• Regional analgesia: caudal epidural, spinal, peripheral nerve blocks - strongly preferred to reduce opioid requirements
• Sucrose and non-nutritive sucking for minor procedures

4. Fluid and Glucose Management

• Continue glucose-containing maintenance fluids
• Monitor blood glucose every 1-2 hours postoperatively
• Resume feeds as early as possible

5. Temperature

• Maintain normothermia in recovery; continue warming measures

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PART 2: PEDIATRIC ANAESTHESIA CONSIDERATIONS

Physiological Basis (Infants and Children)

• Cardiac output becomes less heart-rate dependent as stroke volume increases after infancy
• Cricoid remains narrowest point of airway until age ~5 years
• FRC improves, risk of desaturation decreases (but still faster than adults)
• Drug metabolism approaches adult levels by 6-12 months (hepatic enzymes)
• MAC is highest in infants (3-6 months) and gradually decreases with age

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A. PREOPERATIVE CONSIDERATIONS - PEDIATRIC

1. Assessment

• Age, weight, developmental stage
• Past medical/surgical/anaesthetic history - family history of malignant hyperthermia (MH)
• Current medications (antiepileptics, corticosteroids, antihypertensives - may affect anaesthetic requirements)
• Allergies (especially latex allergy in spina bifida patients)
• Recent URTI: if active URTI with fever/productive cough, elective surgery postponed 4-6 weeks; mild URTI - individualize decision (risk of laryngospasm, bronchospasm increased 7-10x)

2. NPO Guidelines - Pediatric (ASA/Modified Guidelines)

3. Premedication - Pediatric

• Midazolam oral: 0.5 mg/kg (max 15 mg) - anxiolysis 20-30 mins before induction; most commonly used
• Ketamine oral/IM: 5-6 mg/kg oral or 2-4 mg/kg IM - sedation and dissociation in uncooperative children
• Atropine: 0.02 mg/kg (min 0.1 mg) - prevent bradycardia, dry secretions (especially important before ketamine)
• Topical analgesia: EMLA or LMX-4 cream on dorsum of hands before IV placement (applied 45-60 min before)
• Parental presence during induction - reduces anxiety in young children (2-7 years)

4. Investigations

• Hemoglobin if surgery with expected blood loss
• Blood glucose in infants
• ECG, echo if congenital heart disease suspected
• No routine bloods needed for healthy children undergoing minor procedures

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B. INTRAOPERATIVE CONSIDERATIONS - PEDIATRIC

1. Induction of Anaesthesia

• Inhalation induction (most common in children): Sevoflurane 8% in 100% O2 - smooth, non-pungent, rapid
  • Single-breath technique or tidal volume technique
  • Preferred when no IV access and child uncooperative
• IV induction: once IV access secured (with EMLA)
  • Propofol 2.5-3.5 mg/kg (higher dose than adults - greater Vd)
  • Thiopentone 5-7 mg/kg
  • Ketamine 1-2 mg/kg IV
• IM induction (uncooperative/combative): Ketamine 4-6 mg/kg IM

2. Airway Management

• LMA (laryngeal mask airway): appropriate for most elective cases; size by weight
• ETT sizes:
  • Uncuffed: (Age/4) + 4
  • Cuffed: (Age/4) + 3.5
  • Premature: 2.5-3.0 uncuffed
  • Oral ETT depth at lip: age/2 + 12 cm (or 3 × ETT size)
• Cuffed ETTs are acceptable in all age groups including neonates when used with low inflation pressures (<20 cmH2O)
• Straight blade (Miller) for neonates and infants; Macintosh blade for older children

3. Maintenance

• Sevoflurane is preferred inhalation agent (pleasant, rapid emergence)
• Isoflurane: alternative maintenance agent
• MAC values: Halothane MAC peaks in infants; Sevoflurane 3.3% in infants, 2.5% in school-age children
• Remifentanil infusion (0.05-0.2 mcg/kg/min) for opioid component - rapid offset
• Neuromuscular blockade: rocuronium (0.6 mg/kg for intubation), atracurium (0.5 mg/kg)

4. Fluid Management

• 4-2-1 Rule for hourly maintenance fluids:
  • 4 mL/kg/hr for first 10 kg
  • 2 mL/kg/hr for next 10 kg (10-20 kg)
  • 1 mL/kg/hr for each kg >20 kg
• Replace intraoperative losses with isotonic crystalloid (0.9% NaCl, Plasmalyte, Hartmann's)
• Blood transfusion threshold: Hb <7 g/dL in healthy children; <10 g/dL in those with cardiac/respiratory disease
• EBV: 80 mL/kg in infants; 70 mL/kg in older children

5. Drug Dosing Summary (Pediatric)

6. Special Considerations

• Laryngospasm: more common in pediatric patients, especially with URTI
  • Management: CPAP, jaw thrust, deepening anaesthesia (propofol 0.5 mg/kg), succinylcholine 1 mg/kg if complete laryngospasm
• Bronchospasm: treat with 100% O2, deepen anaesthesia (sevoflurane), bronchodilators (salbutamol nebulized)
• Malignant Hyperthermia (MH): triggered by volatile agents + succinylcholine
  • Presentation: rapid rise in ETCO2, hyperthermia, masseter rigidity, tachycardia
  • Treatment: stop trigger, 100% O2, dantrolene 2.5 mg/kg IV (repeat q5 min, total 10 mg/kg)
• PONV (post-operative nausea and vomiting): high risk in children >2 years, strabismus surgery, history of PONV; prophylaxis with ondansetron 0.1 mg/kg

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C. POSTOPERATIVE CONSIDERATIONS - PEDIATRIC

1. Recovery and Emergence

• Smooth emergence preferred - emergence agitation (EA) common with sevoflurane in young children (1-6 years)
  • Prevention: dexmedetomidine 0.5 mcg/kg IV at end of surgery, IV opioids, midazolam
• Criteria for extubation: awake, purposeful movement, adequate tidal volume, SpO2 >95% on air
• Stridor post-extubation: treat with nebulized racemic epinephrine (0.5 mL of 2.25% solution in 3 mL NS), dexamethasone 0.5 mg/kg IV, cool humidified O2

2. Pain Management

• Multimodal approach is standard:
  • Paracetamol ± NSAIDs (ibuprofen, diclofenac - avoid in <3 months; use cautiously in renal impairment)
  • Opioids for moderate-severe pain (morphine, fentanyl, oxycodone)
  • Regional analgesia: caudal (0.25% bupivacaine 1 mL/kg), ilioinguinal block, TAP block
  • Nurse-controlled or patient-controlled analgesia (NCA/PCA) when age-appropriate (>7 years)
• Use validated pain scales: FLACC (<4 years), Wong-Baker FACES (4-12 years), NRS (>12 years)

3. Fluid Management

• Resume oral fluids as soon as tolerated
• IV fluids: isotonic solutions (0.9% NaCl, Plasmalyte) - hypotonic solutions (0.45% NaCl) increase risk of hyponatremia

4. Discharge Criteria (Day Surgery)

• Modified Aldrete/PADSS score
• Alert, no uncontrolled pain, no vomiting, tolerated fluids, passed urine, accompanied by responsible adult
• Must not be discharged to go home alone by taxi

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PART 3: GERIATRIC ANAESTHESIA CONSIDERATIONS

Physiological Basis (Age-Related Changes)

Cardiovascular Changes

• Decreased cardiac reserve: increased arterial stiffness, reduced compliance, left ventricular hypertrophy
• Resting systolic function preserved even in octogenarians, but diastolic dysfunction is common
• Increased incidence of diastolic dysfunction (impaired ventricular relaxation, increased filling pressures)
• Increased vagal tone + decreased adrenergic receptor sensitivity = decreased heart rate response to stress
• Prolonged circulation time - delays onset of IV drugs but speeds inhalation induction
• Exaggerated hypotension at induction of general anaesthesia due to diminished cardiac reserve
• Increased risk of arrhythmias

Respiratory Changes

• Decreased elasticity of lung tissue - overdistension of alveoli, collapse of small airways
• Increased residual volume (RV) and functional residual capacity (FRC)
• Increased closing capacity - airway closure during normal tidal breathing
  • Closing capacity exceeds FRC at age 45 in supine, age 65 in sitting position
• Decreased PaO2 with age: PaO2 (mmHg) = 100 - (age/3) approximately
• Decreased hypoxic and hypercapnic ventilatory drive
• Decreased cough reflex - aspiration risk

Neurological Changes

• Loss of neurons, reduced neurotransmitter synthesis
• Reduced MAC: MAC decreases ~6% per decade after age 40
• Lower dose requirements for all anaesthetic agents
• Increased sensitivity to benzodiazepines, opioids, barbiturates - risk of prolonged sedation
• Pre-existing cognitive impairment common (affects consent, postoperative assessment)
• Risk of Post-Operative Cognitive Dysfunction (POCD) and Post-Operative Delirium (POD)

Renal Changes

• GFR decreases ~1 mL/min/year after age 40 (from 120 mL/min)
• Impaired Na+ handling, decreased concentrating and diluting ability
• Predisposed to both dehydration and fluid overload
• Reduced creatinine production (reduced muscle mass) - serum creatinine may appear normal despite significantly reduced GFR
• Drug accumulation risk (renally cleared drugs: morphine-6-glucuronide, NSAIDs, aminoglycosides)

Hepatic Changes

• Liver mass and hepatic blood flow decline with age
• Hepatic drug clearance declines in proportion to liver mass
• Prolonged half-life of hepatically metabolized drugs (propofol, benzodiazepines, opioids)

Musculoskeletal Changes

• Sarcopenia (loss of muscle mass) - reduced pseudocholinesterase - prolonged succinylcholine effect
• Osteoporosis - positioning injuries, pathological fractures during transfers
• Reduced neck mobility, temporomandibular joint disease - may complicate airway management
• Arthritis - affects positioning, regional anaesthesia placement

Pharmacological Changes

• Pharmacokinetic changes:
  • Increased body fat (increased Vd for lipophilic drugs - prolonged effect)
  • Decreased total body water (reduced Vd for hydrophilic drugs - higher peak concentrations)
  • Reduced plasma albumin - increased free fraction of protein-bound drugs
  • Reduced hepatic/renal clearance
• Pharmacodynamic changes:
  • Reduced MAC for all volatile agents
  • Lower dose requirements for propofol, etomidate, opioids, benzodiazepines, barbiturates

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A. PREOPERATIVE CONSIDERATIONS - GERIATRIC

1. Comprehensive Assessment

• Detailed history: multiple comorbidities, polypharmacy (average geriatric patient takes 5-8 medications)
• Cognitive baseline - screening with MMSE or MoCA
• Frailty assessment - Clinical Frailty Scale (CFS) - strongest predictor of adverse outcomes
• Functional status - activities of daily living (ADLs), MET (metabolic equivalent) level
• Nutritional status - low albumin is a strong predictor of poor surgical outcome
• Hearing aids, dentures, glasses - document; these help orientation and reduce delirium risk postoperatively

2. Recommended Preoperative Investigations (Geriatric)

3. Medication Management

• Continue: beta-blockers, antihypertensives (most), antianginals, anticoagulants (per protocol)
• Hold: ACE inhibitors/ARBs on day of surgery (risk of refractory intraoperative hypotension)
• Hold: NSAIDs, diuretics day of surgery
• Anticoagulation bridging: assess bleeding vs thromboembolism risk
• Drug interactions: polypharmacy increases risk of adverse intraoperative drug interactions

4. Special Preoperative Concerns

• Nutritional optimization: preoperative carbohydrate loading (2 hours before surgery) reduces insulin resistance; nutritional supplements if malnourished
• Prehabilitation: exercise program pre-operatively improves cardiorespiratory reserve
• Advance directives and goals of care discussion
• Consent: capacity assessment if cognitive impairment present

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B. INTRAOPERATIVE CONSIDERATIONS - GERIATRIC

1. Positioning

• Padded pressure points - skin fragile, osteoporotic bones
• Avoid extreme joint positions - arthritis, reduced mobility
• Slow position changes - orthostatic hypotension

2. Monitoring

• Standard ASA monitors
• Arterial line: for major surgeries, anticipated haemodynamic instability
• BIS (Bispectral Index) or other depth-of-anaesthesia monitoring - reduces drug overdose, lowers POCD risk
• Temperature monitoring (hypothermia risk)
• Urine output (Foley catheter) - guide to fluid status

3. Choice of Anaesthesia

• Regional anaesthesia is preferred where feasible - avoids CNS effects, reduces POCD risk, superior postoperative analgesia, reduces opioid requirements
• Spinal anaesthesia: reduced dose requirement (reduced CSF volume, increased spread); hypotension more pronounced - need vasopressors ready (phenylephrine, ephedrine, metaraminol)
• General anaesthesia: titrate carefully due to reduced requirements
  • Induction: propofol dose reduced 30-50% (1-1.5 mg/kg); give slowly, reduce by further 30% if haemodynamically compromised
  • Etomidate (0.2-0.3 mg/kg): preferred if cardiovascularly unstable
  • Ketamine: useful in shocked/hemodynamically unstable patients
  • Avoid ketamine in patients with pre-existing dementia or psychiatric history

4. Maintenance

• Reduced MAC - use lower concentrations of volatile agents; titrate to BIS 40-60
• Desflurane and sevoflurane preferred (rapid emergence, better control)
• Avoid N2O in those with B12 deficiency (common in elderly) or bowel obstruction
• Remifentanil infusion preferred (organ-independent metabolism)
• NMB: atracurium/cisatracurium preferred (organ-independent Hofmann elimination, predictable in elderly)
• Sugammadex preferred for reversal (neostigmine + glycopyrrolate may cause bradycardia/tachycardia in elderly)

5. Haemodynamic Management

• Exaggerated induction hypotension - pre-load with crystalloid if not contraindicated
• Phenylephrine or noradrenaline infusion for vasoplegic hypotension
• Ephedrine for bradycardia-associated hypotension
• Avoid prolonged hypotension (MAP <65 mmHg) - cerebral, renal, and myocardial ischemia risk
• Avoid excessive fluid loading (diastolic dysfunction - does not tolerate fluid overload)
• Goal-directed fluid therapy (GDT) using cardiac output monitoring for major surgeries

6. Temperature

• Hypothermia extremely common in elderly (vasodilation with anaesthesia, poor thermogenesis)
• Active warming mandatory: forced-air warming, warm IV fluids
• Target temperature >36°C

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C. POSTOPERATIVE CONSIDERATIONS - GERIATRIC

1. Emergence and Extubation

• Slower emergence due to prolonged drug effects - do not rush
• Residual neuromuscular blockade: confirm reversal with quantitative TOF monitoring (TOFr >0.9)
• Extubation criteria: awake, cooperative, adequate respiratory parameters
• Risk of aspiration on extubation - suction oropharynx before extubation

2. Post-Operative Delirium (POD) - High Priority

• Definition: Acute disturbance of consciousness, attention, cognition, and perception; fluctuating course
• Incidence: 15-50% in post-surgical elderly patients
• Risk factors: Pre-existing dementia, polypharmacy, sensory impairment, immobility, infection, pain, sleep deprivation
• Prevention:
  • Return hearing aids and glasses immediately on arrival to recovery
  • Reorient patient frequently (date, place, person)
  • Avoid benzodiazepines, anticholinergics, meperidine
  • Adequate pain control (inadequate pain = major delirium trigger)
  • Early mobilization
  • Multicomponent hospital elder life program (HELP)
• Treatment: Identify and treat underlying cause; haloperidol 0.5 mg IV (low-dose) for agitated delirium; quetiapine as alternative

3. Post-Operative Cognitive Dysfunction (POCD)

• Definition: A subtle decline in cognitive function (memory, concentration, attention) compared to preoperative baseline, lasting weeks to months post-surgery
• Distinct from delirium (POCD is not acute, not fluctuating)
• Diagnosed with formal neuropsychological testing
• Risk factors: advanced age, pre-existing cognitive decline, major surgery, deep anaesthesia, poor education
• Prevention: depth of anaesthesia monitoring (target BIS 40-60), avoid excessive hypotension, regional over general if possible

4. Pain Management

• Multimodal analgesia - critical to avoid delirium and facilitate mobilization
• Start with non-opioids: paracetamol (1g QID), NSAIDs (use cautiously - renal risk, GI bleed risk)
• Opioids if required: start at 25-50% of standard adult dose; titrate slowly; monitor closely
• Avoid meperidine (pethidine) - accumulation of norpethidine causes CNS excitation/seizures
• Regional analgesia: epidural, nerve blocks - superior, reduces opioid requirements
• Use validated geriatric pain scales (verbal NRS, or behavioural scales in cognitively impaired patients)

5. Fluid and Electrolyte Balance

• Careful fluid balance - at risk of both dehydration and fluid overload
• Monitor daily electrolytes - risk of dilutional hyponatremia, hypokalemia
• Resume oral intake and oral medications as early as possible

6. Early Mobilization and Rehabilitation

• Immobility in the elderly leads to rapid deconditioning, pressure sores, DVT/PE, pneumonia
• Physiotherapy referral from postoperative day 1
• DVT prophylaxis: LMWH + TED stockings + pneumatic compression devices

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QUICK COMPARISON TABLE

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