I now have a solid understanding of the content. The PDF is a Marrow "World of Revision" anaesthesia notes covering: Pre-Anaesthesia Checkup, Monitoring under GA, IV & Inhalational Agents, Muscle Relaxants, Local Anaesthetics, and Regional Anaesthesia. Let me craft 7th-day revision questions (a mix of MCQ-style and short answer, covering high-yield facts from across the full document).
🩺 7th Day Revision — Anaesthesia
Here are your revision questions. Try to answer each before checking the answer below it!
PRE-ANAESTHESIA CHECKUP
Q1. A patient on SGLT-2 inhibitors is posted for a minor surgery. When should the drug be stopped pre-operatively?
Answer
**24 hours prior** (to avoid euglycemic ketoacidosis - the risk with major surgeries requires stopping 72 hours prior).
Q2. A patient on Clopidogrel is posted for an elective major surgery. How many days before surgery should it be stopped? What bridging is used?
Answer
Stop **5-7 days prior**. Bridge with: **Prophylactic LMWH** (stop 12 hrs before), **Regular heparin** (stop 6 hrs before), or **Therapeutic LMWH** (stop 24 hrs before).
Q3. What is the Modified Mallampati Class III finding on airway exam?
Answer
**Only the base of the uvula is seen** (soft palate and fauces not visible).
Q4. A patient has an MI with stenting 4 months ago. Which ASA grade and which stent-related surgery waiting time applies?
Answer
**ASA Grade III** (MI >3 months ago). Drug-eluting stent requires waiting **6 months** before elective surgery; bare metal stent requires **30 days**.
Q5. What is the Revised Cardiac Risk Index (RCRI) score threshold for >12% risk of post-op cardiac complications, and name the 6 factors?
Answer
Score **>3** = 12% risk. Factors: 1) Major surgery (intraperitoneal/suprainguinal/vascular/emergency), 2) H/o MI, 3) H/o CCF, 4) H/o CVA, 5) Serum Creatinine >2, 6) Diabetes on insulin.
MONITORING UNDER GA
Q6. What does the BIS (Bispectral Index) value of 40-60 indicate? What does a BIS of 0 represent?
Answer
**40-60** = Recommended range (adequate depth of anaesthesia). **0** = Flat EEG / no cerebral activity.
Q7. A patient develops sudden cardiac arrest intra-operatively. EtCO₂ shows a step-ladder pattern and wide QRS complex on ECG. What is the diagnosis and drug of choice?
Answer
**Malignant Hyperthermia**. DOC: **Dantrolene sodium 2.5 mg/kg** diluted in distilled water.
Q8. A patient in the ICU has ↑CVP + ↓BP. What does this suggest? Where is the most common site for CVP catheter insertion?
Answer
**Right heart failure**. Most common site: **Right internal jugular vein (IJV)**. Femoral site has the highest infection risk.
Q9. On capnography, a "curare cleft" pattern is seen. What does it indicate?
Answer
**Recovering from the effect of a muscle relaxant** - patient is making spontaneous breathing efforts.
Q10. Methemoglobin causes SpO₂ to read falsely at what fixed value? What condition is associated with carboxyhemoglobin?
Answer
MetHb: SpO₂ fixed at **85%**. CarboxyHb: SpO₂ falsely **elevated** (e.g., fire/CO poisoning).
IV & INHALATIONAL INDUCTION AGENTS
Q11. A patient accidentally receives an intra-arterial injection of thiopentone. What is the management?
Answer
1. **Do NOT remove the needle** (causes vasospasm). 2. Inject **saline/heparin** through the needle. 3. **Stellate ganglion block** (lower cervical sympathetic ganglion) to cause vasodilation.
Q12. Which IV induction agent is: (a) Contraindicated in neuro-surgery due to pro-epileptic activity, (b) Agent of choice for cardiac surgery, (c) Agent of choice in asthma/COPD?
Answer
a) **Methohexital** (methyl group makes it pro-epileptic). b) **Etomidate** (most cardio-stable). c) **Ketamine** (excellent bronchodilator).
Q13. Propofol infusion syndrome - when does it occur and what are the classic features?
Answer
Avoid propofol infusion **≥48 hours**. Features: **Green-coloured urine**, metabolic acidosis, asystole.
Q14. Rank these agents from fastest to slowest induction based on Blood:Gas partition coefficient: Halothane, Desflurane, Sevoflurane, Isoflurane, N₂O.
Answer
Fastest → Slowest (lowest to highest B/G ratio): **Desflurane → N₂O → Sevoflurane → Isoflurane → Halothane**
Q15. What are the contraindications for Nitrous Oxide (N₂O)?
Answer
1. **Pneumothorax** (rapid diffusion expands air spaces). 2. **Middle ear and retina surgery**. 3. Interferes with **Vitamin B₁₂ metabolism** → megaloblastic anemia, subacute combined degeneration of SC.
MUSCLE RELAXANTS
Q16. Why is succinylcholine contraindicated in burns, hemiplegia, and paraplegia? Up to when is it contraindicated?
Answer
Damage to ACh receptors → **upregulation of extrajunctional receptors** → massive K⁺ release → hyperkalemic cardiac arrest. Contraindicated **up to 6 months** after the event.
Q17. What is "scoline apnea"? What is the investigation and treatment?
Answer
Prolonged apnea (6-8 hrs) due to **atypical pseudocholinesterase** (genetically determined). Ix: **Dibucaine number** (normal ~80, atypical ~20). Rx: **Continue mechanical ventilation + Fresh Frozen Plasma (FFP)**.
Q18. Which NDMR is the agent of choice for: (a) Rapid sequence intubation, (b) Day care surgery, (c) Liver/kidney failure?
Answer
a) **Rocuronium** (onset 30 seconds). b) **Rocuronium** (day care surgery AOC). c) **Cisatracurium** (Hoffman's degradation, no organ-dependent metabolism).
Q19. What is the most reliable bedside test for adequate reversal of neuromuscular blockade?
Answer
**Able to lift head for >5 seconds** (most reliable bedside test). Gold standard: **Train-of-Four (ToF) ratio >0.9**.
LOCAL ANAESTHETICS
Q20. Why is local anaesthetic less effective in an infected/pus-filled area?
Answer
Infected areas have **↓pH** → ↑ionized form of LA → ↓entry into cell → ↓action of LA.
Q21. Which local anaesthetic has a LOW CC/CNS ratio and what does this mean clinically?
Answer
**Bupivacaine and Ropivacaine** - low CC/CNS ratio means **cardiovascular collapse occurs BEFORE or at the same time as CNS toxicity** (VF/cardiac arrest). Treatment: **20% Intralipid 1.5 mL/kg** bolus then 0.25 mL/kg/hr infusion.
Q22. EMLA cream - composition, use, and a key adverse effect in neonates?
Answer
Eutectic mixture of **lignocaine + prilocaine** (2.5% or 5%). Uses: painless cannula insertion, dermatological procedures. Adverse effect in neonates: **Methemoglobinemia** (falsely ↓SpO₂ values).
REGIONAL ANAESTHESIA
Q23. What is the absolute contraindication list for spinal anaesthesia?
Answer
1. Raised ICP. 2. Severe mitral/aortic stenosis. 3. Bleeding disorders. 4. Local site infection. 5. Severe hypovolemia. 6. Allergy to drug. 7. Patient refusal.
Q24. A young woman develops a headache 36 hours after LSCS that worsens on standing and improves on lying down. Diagnosis? Treatment for severe cases?
Answer
**Post-Dural Puncture Headache (PDPH)**. Mild: bed rest + IV fluids + caffeine + paracetamol. Severe cases: **Epidural blood patch**.
Q25. In spinal anaesthesia, if a hyperbaric drug is used and the patient is placed in Trendelenburg (head-down) position, what happens to the level of block?
Answer
**Higher level of block** (hyperbaric drug settles/sinks caudally under gravity in head-down position, moving toward the head end).
Good luck with your revision! 🎯 These 25 questions cover all major topics in the PDF. Let me know if you want more questions on any specific section or want a timed quiz format.
