DNB Theory Exam Answers (10 Marks Each)

QUESTION 1: Pharmacology of Antifibrinolytics and Use of Tranexamic Acid in Anesthesia and Intensive Care - Evidence For and Against

INTRODUCTION

CLASSIFICATION OF ANTIFIBRINOLYTICS

• Tranexamic acid (TXA)
• Epsilon-aminocaproic acid (EACA)

• Aprotinin (withdrawn from most markets due to safety concerns)

PHARMACOLOGY

Tranexamic Acid (TXA)

• TXA is approximately 10 times more potent than EACA
• It has a longer half-life (~2-3 hours) compared to EACA (~1-2 hours)

• Standard dose: 10 mg/kg IV followed by 1 mg/kg/hr infusion (though pharmacokinetic studies suggest larger doses may be needed to maintain effective plasma levels)
• Some protocols use a 1 g IV bolus over 10 minutes (as in CRASH-2 protocol) followed by 1 g over 8 hours
• Topical: 1-3 g in irrigation solutions (joint arthroplasty)

Epsilon-Aminocaproic Acid (EACA)

• Less potent (higher doses required)
• Shorter half-life
• Higher incidence of side effects (myopathy, rhabdomyolysis with prolonged use)
• Less widely used clinically

• Loading dose: 50-75 mg/kg IV
• Maintenance: 20-25 mg/kg/hr
• Or standardized: 5-10 g load, then 1 g/hr

Aprotinin

• A naturally occurring serine protease inhibitor from bovine lung
• Inhibits plasmin, kallikrein, and trypsin
• Withdrawn globally in 2007-2008 due to increased risk of mortality, renal failure, MI, and stroke (BART trial)
• Limited re-approval in some countries for isolated use in high-risk cardiac surgery

ANTIFIBRINOLYTICS IN ANESTHESIA AND INTENSIVE CARE

1. Cardiac Surgery

• Patients undergoing repeat cardiac operations
• Patients refusing blood products (Jehovah's Witnesses)
• Pre-existing coagulopathy
• Recent glycoprotein IIb/IIIa inhibitor use
• Long complex procedures
• Patients on dual antiplatelet therapy (aspirin + clopidogrel)

2. Trauma and Hemorrhagic Shock

KEY LANDMARK TRIALS - EVIDENCE FOR AND AGAINST

EVIDENCE IN FAVOUR

• Multicenter, prospective, randomized, double-blind, placebo-controlled trial
• >20,000 patients with significant traumatic bleeding
• TXA 1g IV over 10 min followed by 1g over 8 hours
• Results: Significant reduction in all-cause mortality (RR 0.91, 95% CI 0.85-0.97) and death due to bleeding (RR 0.85, 95% CI 0.76-0.96)
• No increase in vascular occlusive events (DVT, PE, MI, stroke)
• Key finding: Benefit was greatest when TXA was given within 1 hour of injury, still significant within 3 hours
• This is the only Class I evidence for a 30-day survival benefit in trauma resuscitation (Miller's Anesthesia, 10e)

• Observational study, 896 consecutive trauma admissions, 293 received TXA
• Despite TXA patients being more severely injured, they had lower mortality
• Greatest benefit seen in patients receiving >10 units PRBCs in 24 hours
• Confirmed survival benefit in massive hemorrhage

• 12,000 patients with traumatic brain injury (TBI) without major extracranial bleeding

• In mild-to-moderate TBI: TXA lowered TBI-related death (RR 0.78, CI 0.64-0.95)
• Patients with reactive pupils had decreased TBI-related death (RR 0.87)
• No significant benefit in severe TBI
• No increase in vascular occlusive events or seizures (Barash, 9e)

• Multiple meta-analyses (including Al Naimi et al., 2024, PMID 39082365 and Guinness et al., 2025, PMID 39652279) demonstrate TXA reduces postpartum hemorrhage in cesarean deliveries
• Used prophylactically (1g IV at skin incision) and therapeutically
• WOMAN trial (2017): TXA given within 3 hours of vaginal/CS birth reduces death from PPH by 19%

• Meta-analyses confirm TXA reduces blood loss and transfusion in hip/knee arthroplasty
• Topical TXA (1-3g in irrigation) equally effective with potentially lower systemic exposure

• Multiple meta-analyses show reduced blood loss

• Systematic review (Zou et al., 2024, PMID 37962715): TXA maintains platelet function during CPB, reducing postoperative bleeding

EVIDENCE AGAINST / CONCERNS

• A critical study of 180 trauma patients found:
  • 64% had fibrinolytic shutdown (mortality 17%)
  • 18% had physiologic fibrinolysis (mortality 3% - the best outcome)
  • 18% had hyperfibrinolysis (mortality 44%)
• The authors cautioned against universal TXA use - it may worsen mortality in patients who already have fibrinolytic shutdown
• TXA is most beneficial in the hyperfibrinolytic state; counterproductive in shutdown

• Mortality actually increased when TXA was initiated after 3 hours of injury
• Risks outweigh benefits in late presenters - implies early or nothing

• Systematic review by Tsan et al. (2023, PMID 37314744) evaluated thromboembolic risk in non-cardiac surgery
• Prophylactic IV TXA has a measurable risk of DVT/PE, particularly in high-risk populations
• Requires individualized risk-benefit assessment

• High-dose TXA (particularly in cardiac surgery) is associated with dose-dependent seizure risk (postoperative seizures, excitatory neurotoxicity via inhibition of GABA and glycine receptors)
• This is a real concern when TXA accumulates in CSF

• Relatively modest number of patients received blood products - questioned external validity
• No difference in actual blood transfusion requirements
• No TEG/ROTEM-guided phenotyping of fibrinolytic state before treatment

• TXA is renally cleared; in renal impairment, accumulation can occur - dose adjustment mandatory

• Active thromboembolic disease
• Known allergy
• Subarachnoid hemorrhage (relative - risk of cerebral vasospasm)
• Disseminated intravascular coagulation with active fibrinolysis (relative)

SUMMARY TABLE

QUESTION 2: Stress and the Anesthesiologist - Including Burnout Syndrome

INTRODUCTION

SOURCES OF STRESS IN ANESTHESIOLOGY

1. Clinical Stressors

• Anesthesiologists manage multiple physiological parameters simultaneously in real time
• Drug interactions, dose calculations, airway management, hemodynamic instability
• "A moment's inattention can lead to catastrophe" - unique feature of the specialty

• Anaphylaxis, can't-intubate-can't-oxygenate (CICO), malignant hyperthermia, massive hemorrhage
• These events are unpredictable and require immediate precise action under extreme pressure

• Anesthesia-related adverse events, even when unavoidable, carry profound guilt and second-victim phenomenon

• Emergencies, full lists, add-on cases, pressure from surgeons
• Fatigue from prolonged procedures

• Sleep deprivation is a major stressor - impairs concentration, reaction time, and judgment
• A review (Ippolito et al., 2024, PMID 38641516) in British Journal of Anaesthesia confirmed that fatigue impairs both anesthetist well-being and patient safety

2. Workplace and Systemic Stressors

• Surgeon-anesthesiologist relationship friction
• Conflicts with nursing staff, administrators
• Hierarchy and bullying in some institutional cultures

• Documentation, compliance, audit requirements
• Reduced "meaning" from increased paperwork

• Fear of litigation; perceived vulnerability
• Increased defensive practice

• Dramatically amplified all stressors - high-risk airway procedures, PPE burden, moral distress, ICU deaths, understaffing
• Study (Aron et al., 2021, PMID 34715972) reviewed COVID-19's impact on anesthesiologists' well-being and found substantial deterioration

• Female anesthesiologists face additional burnout burden from gender inequity, the "double shift" at home, implicit bias
• Malinzak & Byerly (2022, PMID 35659396) reviewed burnout through the lens of gender inequity in the pandemic period

BURNOUT SYNDROME IN ANESTHESIOLOGISTS

Definition

Epidemiology

• Prevalence of burnout in anesthesiology: reported 25-50% in various studies (varying by country, system, definition)
• A review from South Korea (Lee J, 2025, PMID 40350153) noted comparable rates across different healthcare systems
• Anesthesiology consistently ranks among the top specialties for burnout alongside emergency medicine and critical care

Risk Factors

• Perfectionist personality
• Poor coping strategies
• Social isolation
• Substance use disorder (higher than average in anesthesiologists - access to opioids/propofol)
• History of anxiety or depression

• Night call burden
• High caseload, lack of control
• Poor mentoring
• Inadequate peer support
• Solo practice in smaller hospitals

• Poor leadership
• Inadequate staffing
• Lack of autonomy
• Toxic workplace culture

Consequences of Burnout

• Depression, anxiety, substance misuse
• Suicidal ideation (physicians have higher suicide rates than general population)
• Relationship breakdown, social withdrawal
• Physical health consequences (hypertension, immune suppression)

• Shin et al. (2023, PMID 37278062) in Permanente Journal documented that physician burnout significantly impacts patient care quality and safety in perioperative medicine
• Increased medication errors, near-misses
• Reduced vigilance - particularly dangerous during long monotonous cases
• Decreased communication and teamwork

THE SECOND VICTIM PHENOMENON

• Acute stress reaction
• Self-doubt, guilt, and intrusive thoughts
• Without institutional support, this progresses to PTSD or burnout
• The culture of "blame" rather than "learning" exacerbates this

PREVENTION AND MANAGEMENT

Individual Strategies

• Mindfulness meditation and self-awareness programs
• Regular physical exercise
• Adequate sleep hygiene and rest between calls
• Psychotherapy and counseling
• Peer support groups
• Interests outside medicine ("defragment" the self)
• Recognizing early warning signs in oneself

Institutional/Systemic Strategies

• Duty hour regulations - limitation of consecutive working hours
• Fair, transparent scheduling
• Safe reporting culture - eliminating blame
• Peer support programs for second victims
• Mental health resources (Employee Assistance Programs)
• Structured debriefing after critical events
• Mentoring programs - particularly for trainees and junior consultants
• Leadership training - creating psychologically safe workplaces
• Addressing gender and diversity-related inequities

Structural Reforms

• Adequate staffing ratios
• Reduction of non-clinical administrative work
• Team-based care models reducing individual burden

CONCLUSION

QUESTION 3: HELLP Syndrome and the Anesthesiologist

INTRODUCTION

• H - Hemolysis (microangiopathic)
• EL - Elevated Liver enzymes
• LP - Low Platelets

EPIDEMIOLOGY AND PATHOPHYSIOLOGY

• Incidence: 0.1-0.8% of all pregnancies; 10-20% of severe preeclampsia
• Usually occurs in the third trimester (28-36 weeks); can present postpartum (up to 48 hours)
• Underlying mechanism: endothelial dysfunction from abnormal placentation leads to vascular injury, platelet consumption, fibrin deposition, and microangiopathic hemolysis
• The liver is particularly vulnerable due to periportal fibrin deposition causing hepatocellular necrosis

DIAGNOSTIC CRITERIA

Tennessee Classification (Sibai)

Mississippi Triple-Class System

MATERNAL COMPLICATIONS (Anesthesiologist Must Be Aware)

1. Disseminated Intravascular Coagulation (DIC) - 20% of HELLP cases
2. Hepatic subcapsular hematoma / rupture - catastrophic; may present as shoulder tip pain, acute abdomen
3. Acute renal failure - oliguria, proteinuria
4. Pulmonary edema - capillary leak + low oncotic pressure
5. Placental abruption - 10-20% of HELLP
6. Eclampsia - 6% of HELLP
7. Maternal mortality - 1-3% in severe cases
8. Cerebral hemorrhage - from uncontrolled hypertension

ANESTHESIA CONSIDERATIONS - THE CORE QUESTION

A. Pre-anesthetic Assessment

• Platelet count - trend is as important as absolute value; a falling count is more dangerous than a stable low count
• Coagulation profile - PT, aPTT, fibrinogen (screen for DIC)
• LFT, RFT - hepatic and renal function
• Airway assessment - preeclampsia causes generalized edema, including airway edema; potentially difficult intubation
• Fetal status - in consultation with obstetrician
• Blood pressure - antihypertensive therapy optimization

B. Neuraxial vs. General Anesthesia - The Central Dilemma

Neuraxial Anesthesia (Spinal / Epidural / CSE)

• Preferred technique for preeclampsia and eclampsia with severe features (ACOG position)
• Provides superior pain relief, attenuates hypertensive catecholamine surges
• Avoids the risks of general anesthesia (difficult airway, aspiration, hypertensive response to laryngoscopy)
• Does not require fluid preloading with dilute LA/opioid solutions

• HELLP syndrome characteristically causes thrombocytopenia, raising the risk of spinal/epidural hematoma
• There is no single platelet count or coagulation test that definitively predicts safe neuraxial block
• Review of 1.7 million spinal/epidural blocks: Two obstetric patients developed neuraxial hematoma - both had HELLP syndrome (Creasy & Resnik's Maternal-Fetal Medicine)
• Despite this, incidence of spinal hematoma in obstetric patients is extremely low (~1 per 200,000)

• Platelets >100,000/mm³: Neuraxial anesthesia generally safe
• Platelets 70,000-100,000/mm³: Many experienced anesthesiologists consider neuraxial safe if platelet count is stable (not falling), no clinical bleeding signs, and coagulation studies are normal
• Platelets <70,000/mm³: Most anesthesiologists would avoid neuraxial block
• Platelets <50,000/mm³: Neuraxial block is generally contraindicated

• TEG/ROTEM can provide additional information on clot formation and fibrinolysis, but no specific cutoff value predicts complications
• Clinical signs of bleeding (oozing at IV sites, petechiae, gum bleeding) are important clinical indicators

• Concerning/difficult airway examination
• Prolonged labor anticipated
• Stable platelet count, no clinical bleeding signs

• Clinical signs of bleeding (oozing at venepuncture sites)
• Rapidly falling platelet count
• Need for urgent/emergency cesarean delivery
• DIC present
• Reassuring airway examination

General Anesthesia in HELLP

• Preeclampsia/HELLP causes generalized edema including oropharynx, tongue, larynx
• Failed intubation rate is higher in obstetric patients; CICO is a real risk
• Rapid-sequence induction (RSI) is mandatory (full stomach risk)
• Airway assessment, preparation of difficult airway trolley, video laryngoscope, surgical airway plan
• Consider awake fibreoptic intubation if anticipated very difficult airway

• A major concern - intracranial hemorrhage can result from an acute hypertensive surge
• Attenuation strategies: labetalol 10-20 mg IV, lignocaine 1.5 mg/kg IV, magnesium, remifentanil, GTN patch
• Target: maintain systolic BP <160 mmHg at all times

• Most HELLP/eclampsia patients receive IV magnesium sulfate for seizure prophylaxis/treatment
• Magnesium potentiates neuromuscular blockade (both depolarizing and non-depolarizing agents)
• Dose of suxamethonium should be maintained at 1-1.5 mg/kg (still effective despite potentiation)
• Reduce doses of non-depolarizing agents by 30-50%; monitor with nerve stimulator
• Signs of magnesium toxicity: loss of deep tendon reflexes → respiratory paralysis → cardiac arrest
• Antidote: Calcium gluconate 1g IV (10 mL of 10%)

• Magnesium reduces MAC of volatile agents
• Use adequate volatile concentration and/or propofol TIVA; use processed EEG monitor (BIS) if available

• Treat hypertension aggressively but avoid hypotension
• Target: SBP 140-160 mmHg, DBP 90-105 mmHg
• Avoid uteroplacental hypoperfusion

• Endothelial damage → capillary leak → pulmonary edema with fluid overload
• Limit fluids to 80-100 mL/hr (total intake including magnesium and oxytocin infusions)
• Avoid aggressive crystalloid/colloid preloading before spinal anesthesia
• Vasopressors (phenylephrine, ephedrine) preferred over fluids to treat hypotension

C. Postoperative Management / ICU Care

• Continue magnesium for 24-48 hours postpartum (seizure risk extends into postpartum)
• Aggressive BP control (antihypertensives)
• Monitor: hourly urine output (Foley), LFTs, platelet count (nadir at 24-48 hours postpartum, then should improve)
• HELLP usually resolves within 3-7 days after delivery
• Platelet transfusion: generally when <20,000/mm³, or <50,000/mm³ if actively bleeding or before surgery
• Fresh frozen plasma for DIC
• Corticosteroids (dexamethasone): controversial - may improve platelet count and laboratory parameters but no proven improvement in maternal clinical outcomes (not universally recommended)
• HDFC (High-dose furosemide and corticosteroids) protocol for Class 1 HELLP in ICU - institutional variation

D. Communication and Teamwork

• HELLP syndrome demands a multidisciplinary team: obstetrician, anesthesiologist, neonatologist, hematologist, and intensivist
• Clear communication regarding evolving platelet counts, coagulation status, and urgency of delivery
• Pre-surgery safety briefing and debrief

DEFINITIVE TREATMENT

SUMMARY TABLE

• PMID 37803822: Optimizing Delivery Strategies in Eclampsia (Review, 2023)
• PMID 37314744: Tranexamic acid and thromboembolism - systematic review/MA (Anaesthesia, 2023)
• PMID 39082365: TXA prophylaxis in caesarean section - MA (2024)
• PMID 38641516: Fatigue, anaesthetist well-being and patient safety (BJA, 2024)
• PMID 37278062: Physician burnout and patient safety in perioperative medicine (2023)
• PMID 40350153: Burnout and well-being for anesthesiologists (2025)