Dr. Jhanvi Bajaj

DNB June 2026 Paper 1 Discussed By Dr. Jhanvi Bajaj: MAC Question| What Residents Should Revise 

by with No Comment Anesthesia

Estimated reading time: 6 minutes

The DNB June 2026 Paper 1 included several questions that were closely aligned with previously asked concepts. One of the recalled questions focused on Minimum Alveolar Concentration (MAC), its definite. 

Let’s break it down the way you would actually revise it before an exam. 

First things first: What exactly is MAC? 

Minimum Alveolar Concentration (MAC) is the minimum alveolar concentration of an inhalational anesthetic at 1 atmosphere pressure that prevents movement in response to a standard surgical incision in 50% of patients. 

That definition can look unnecessarily complicated when you first read it. 

The easiest way to understand it is: 

MAC tells you how much of a volatile anesthetic is needed to prevent movement during surgery in 50% of patients. 

And there is one relationship you should not forget: 

Lower MAC = Higher potency 

Higher MAC = Lower potency 

For example, the MAC of sevoflurane is around 2%, whereas desflurane has a MAC of around 6%. 

So, a lower concentration of sevoflurane is needed to achieve the same endpoint. 

That means: 

Sevoflurane is more potent than desflurane. 

This is why MAC is useful when comparing the potency of inhalational anesthetic agents. 

Important MAC values to revise 

You don’t need to turn this into a memory exercise where you keep staring at numbers for hours. Start by knowing the approximate values and, more importantly, their order. 

Inhalational agent Approximate MAC 
Methoxyflurane 0.16% 
Halothane 0.75% 
Isoflurane 1.4% 
Sevoflurane 2% 
Desflurane 6% 
Nitrous oxide 104% 

Methoxyflurane has a very low MAC, which means high potency. However, it is not commonly used because of its nephrotoxicity. 

For exams, knowing the commonly tested values is more useful than trying to memorise every possible number. 

Factors that decrease MAC 

Now comes the part that is often tested in MCQs and theory questions. 

Think about it this way: 

If the patient is already more sedated or more sensitive to anesthetic effects, you need less volatile anesthetic. 

So MAC goes down. 

Important factors include: 

  • Increasing age 
  • Hypothermia 
  • Hypoxia 
  • Pregnancy 
  • Opioids 
  • Benzodiazepines 
  • Alpha-2 agonists such as dexmedetomidine and clonidine 
  • Acute alcohol intoxication 

A simple revision line: 

Elderly + hypothermia + pregnancy + CNS depressants → ↓ MAC 

Pregnancy 

Pregnancy is a particularly important association. 

The requirement for inhalational anesthetic decreases during pregnancy. Increased progesterone levels are one of the factors associated with this increased sensitivity. 

So, for a quick recall: 

Pregnancy → ↓ MAC 

Acute alcohol vs chronic alcohol: Don’t mix them up 

This is one of those small differences that can easily cost you a mark. 

Acute alcohol intoxication → ↓ MAC 

The patient is already under the sedative effects of alcohol, so less anesthetic is required. 

Chronic alcohol use → ↑ MAC 

With chronic exposure, tolerance develops. The patient is therefore less sensitive to the sedative effects, and the anesthetic requirement increases. 

So remember: 

Acute alcohol = decrease 

Chronic alcohol = increase 

Factors that increase MAC 

Now flip the concept. 

If the patient is more stimulated, has increased metabolic activity, or has developed tolerance to a sedative substance, the anesthetic requirement can increase. 

Important factors include: 

  • Hyperthermia 
  • Hypernatremia 
  • Acute cocaine use 
  • Chronic alcohol use 
  • Chronic amphetamine use 
  • Infancy, particularly around 6 months of age 

Again, don’t just memorise the list. Try to understand the pattern. 

Age and MAC 

Age is an important one. 

MAC is relatively high in infancy and reaches its maximum around 6 months of age. 

After that, it gradually decreases with age. 

So: 

Infant → higher MAC 

Elderly → lower MAC 

This comparison is worth remembering because it can easily appear as an MCQ. 

What does not significantly affect MAC? 

Not every patient characteristic changes MAC. 

The commonly recalled points include: 

  • Gender 
  • Thyroid disease 
  • Duration of anesthesia 

These are useful to remember because they can be used as distractors in exam questions. 

What about the CNS effects? 

The recalled DNB question also asked about the effects of inhalational anesthetic agents on the CNS. 

Volatile anesthetics produce dose-dependent CNS depression. Their effects include changes in: 

  • Consciousness 
  • Memory 
  • Cerebral activity 
  • Immobility 

They can also alter cerebral blood flow and intracranial dynamics, which is why their CNS effects are clinically important rather than being just a theory topic. 

When preparing this part for theory, don’t learn it as a random list. Try to connect each effect with its clinical relevance. 

How should you write this answer in DNB theory? 

If you get a similar question in your exam, don’t start writing everything you remember about inhalational anesthetics. 

Keep the answer organised. 

A simple structure would be: 

1. Definition of MAC 

2. Relationship between MAC and potency 

3. Important MAC values 

4. Factors decreasing MAC 

5. Factors increasing MAC 

6. Factors with little or no effect on MAC 

7. CNS effects of inhalational anesthetics 

This makes your answer easier to follow and also reduces the chance of leaving out one part of a multi-component question. 

Five-minute revision before the exam 

If you are revising MAC at the last minute, ask yourself: 

Can I define MAC in one sentence? 

Can I explain why lower MAC means greater potency? 

Do I remember the approximate MAC of sevoflurane and desflurane? 

What happens to MAC in pregnancy? 

What happens in elderly patients? 

Can I differentiate acute and chronic alcohol use? 

Which drugs decrease MAC? 

Which conditions increase MAC? 

If you can answer these without looking at your notes, your basic MAC revision is in good shape. 

The bigger lesson from this DNB paper 

The important takeaway isn’t just MAC. 

The June 2026 Paper 1 recalls show why residents should not ignore previously asked and repeatedly tested concepts while preparing for DNB theory. 

A topic that looks simple can still become a full-length theory question when the examiner asks for its definition, clinical factors, numerical values and physiological effects together. 

So while revising, don’t just ask: 

“Have I read this topic?” 

Ask: 

“Can I write this topic as a structured answer if it comes in my paper tomorrow?” 

That small change in the way you revise can make your preparation much more exam-oriented. 

Note: This discussion is based on student recalls of the DNB June 2026 Paper 1. The exact question paper was not available at the time of the discussion. 
 
Watch Video: DNB JUNE 2026 – PAPER 1 | MAC Question Discussion | Dr. Jhanvi Bajaj 

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Dr. Jhanvi Bajaj

DNB Oct 2025 (Paper 2, Part 3): Spinal Additives, PDPH, & Neurological Complications Explained by Dr. Jhanvi Bajaj

by with No Comment Anesthesia

Estimated reading time: 4 minutes

DNB theory examiners love testing whether you actually understand clinical concepts or if you’ve just blindly memorized a textbook. A perfect example is this high-yield question from the October 2025 exam, which links three massive topics: Spinal Additives, Neurological Complications, and PDPH. 

At first glance, it looks like an absolute mountain of text to write. But if you structure your thoughts systematically, it is actually an easy question to score top marks on. 

1. Mastering Spinal Additives 

Spinal additives are mixed with local anesthetics (like bupivacaine) to improve block quality, speed up onset, and prolong analgesia. To score well, don’t just dump a random list of drugs on the page—classify them clearly. 

Opioids 

  • Fentanyl: Highly popular for excellent, rapid analgesia with minimal hemodynamic shifts. 
  • Morphine: The gold standard for long-lasting postoperative pain relief, but you must monitor for delayed respiratory depression. 
  • Sufentanil: Provides intense analgesia with a shorter duration and fewer respiratory risks than morphine. 

Alpha-2 Agonists 

  • Clonidine & Dexmedetomidine: Act on the dorsal horn of the spinal cord to blunt pain signaling. Anesthesiologists love clonidine for significantly extending both sensory and motor blocks, though you must watch out for bradycardia, hypotension, and mild sedation. 

Vasoconstrictors 

  • Adrenaline: Constricts local blood vessels to reduce the systemic uptake of the local anesthetic. This keeps the drug at the source longer, extending the block’s lifespan. 

Other Additives 

  • Ketamine, Magnesium Sulfate, Midazolam, and Neostigmine. 
  • The Golden Rule: Every intrathecal additive must be preservative-free. Preservatives are highly neurotoxic and can cause severe, permanent neural damage. 

2. Neurological Complications of Spinal Anesthesia 

While spinal anesthesia is incredibly safe, complications happen. Focus heavily on these three major ones for your answer: 

Post-Dural Puncture Headache (PDPH) 

  • The Cause: Continuous leakage of CSF through the dural puncture site drops intracranial pressure. 
  • The Presentation: A severe frontal or occipital headache that is intensely postural (worsens on sitting/standing, improves when lying flat). It typically sets in within 24–48 hours. 
  • The Mechanism: Loss of CSF cushioning creates traction on pain-sensitive intracranial structures and cranial nerves, causing compensatory cerebral vasodilation. 
  • Treatment: Bed rest, aggressive hydration, simple analgesics, and caffeine. The gold standard for persistent cases is an epidural blood patch. 

Epidural Hematoma 

  • The Cause: Accidental vascular puncture during needle insertion, with the risk skyrocketing in anticoagulated patients. 
  • The Presentation: Sudden, severe back pain paired with rapidly progressing lower limb weakness or paraplegia. 
  • The Action: This is a surgical emergency requiring immediate decompression to avoid permanent paralysis. 

Meningitis 

  • The Cause: Bacterial contamination of the subarachnoid space due to a breach in sterile technique. 
  • The Presentation: High fever, neck stiffness, severe headache, and positive Kernig’s/Brudzinski’s signs. Confirmed via CSF analysis and treated with immediate, targeted antibiotics. 

💡 Quick-Yield Complications to Mention: 

  • TNS (Transient Neurological Symptoms): Buttock and thigh pain historically tied to hyperbaric lidocaine; resolves spontaneously. 
  • Cauda Equina Syndrome: Rare, devastating nerve root damage causing bowel/bladder dysfunction and saddle anesthesia. 
  • Anterior Spinal Artery Syndrome: Ischemia to the anterior two-thirds of the cord, causing motor loss but sparing proprioception. 
  • Arachnoiditis: Severe chronic inflammation often triggered by preservatives or contaminants. 

3. Factors Influencing PDPH 

The risk of a patient developing PDPH boils down to a mix of patient anatomy and provider technique: 

Patient-Specific Factors Procedure-Related Factors 
• Young age (elastic dural fibers) • Multiple puncture attempts 
• Female gender • Larger needle gauges 
• Pregnancy / Labor • Cutting-tip needles (e.g., Quincke) 
• Prior history of PDPH or chronic headaches • Perpendicular bevel orientation 

The Classic Exam Scenario: A young, pregnant female undergoing a C-section where an inexperienced operator makes multiple attempts using a large, cutting needle. She ticks every single risk factor box. 

Wrapping Up 

Instead of trying to memorize these lists blindly, focus on the underlying clinical anatomy. Once you understand the why, recalling it under exam pressure becomes second nature. 

Want to take the stress out of your exam prep? We’ve got you covered. 

  • Watch the full video breakdown: Head over to Conceptual Anesthesia on YouTube to watch this complete session. 
  • Get the complete series: Download the eConceptual and subscribe to Anesthesia  to unlock all our high-yield exam sessions, structured notes, and practical fundamental guides designed to help you ace your DNBs! 

Watch Video: DNB Oct 2025 Paper 2 Part 3 | Spinal Additives, PDPH & Neurological Complications | Dr. Jhanvi Bajaj 

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Dr. Jhanvi Bajaj

LMA Types Explained for PDCET & DNB Exams: First vs Second Generation LMA by Dr. Jhanvi Bajaj 

by with No Comment Anesthesia

Estimated reading time: 6 minutes

Airway management is an important topic in anesthesia, and Laryngeal Mask Airways (LMAs) are frequently asked about in exams like PDCET and DNB. In this session, Dr. Jhanvi Bajaj explains the different types of LMAs, how to identify them, and the key exam points you should remember. 

Let’s go through them step by step. 

First Generation LMAs 

Let’s start with the first generation LMAs. 

They are called first generation because they have only a single tube coming out of them. This single tube is the airway tube. 

Since these LMAs do not have a separate gastric drainage tube, they are prone to the risk of aspiration. They also do not create a strong seal with the larynx, which is why they are not preferred in many situations today. 

However, you must still be able to identify them in exams. 

LMA Classic 

The first LMA you may see is the LMA Classic. 

Features include: 

  • A silicon cuff 
  • A pilot balloon used to inflate the cuff 
  • A single airway tube 

This is the classic reusable LMA. 

LMA Unique 

Now imagine an LMA that looks similar to the LMA Classic, but it is disposable. 

This one is made of PVC material, which means it is designed for single use. 

You use it once and discard it, and this LMA is called LMA Unique. 

Important Exam Point 

A common exam question is: 

How many times can silicon-based LMAs be reused? 

The answer is up to 40 times. 

The method of sterilization used for LMAs is autoclaving. 
So the sequence is: 

  1. Wash the LMA 
  1. Sterilize it using autoclaving 
LMA Flexible 

Another important LMA for exams is the LMA Flexible. 

It is commonly used in: 

  • Head and neck surgeries 
  • Intraoral surgeries 
  • Neurosurgeries 
  • Situations where the patient may be in the prone position 

This LMA is still first generation, because it has only one tube. 

How do you identify it? 

Inside the tube, you will notice small metallic wirings. These wires allow the LMA to bend at different angles without kinking the lumen. 

Because of this flexibility, it is very useful when the airway needs to be shared with the surgeon. 

Second Generation LMAs 

Now let’s move to second -generation LMAs. 

The major difference is simple: 

Second generation LMAs have two tubes. 

These include: 

  • A large airway tube used for ventilation 
  • A smaller gastric drainage tube 

The gastric drainage tube allows insertion of a Ryle’s tube, which helps remove gastric or esophageal contents. This significantly reduces the risk of aspiration. 

Other parts you may notice include: 

  • Fixation tab – helps secure the LMA at the teeth 
  • Bite block – prevents damage to the LMA if the patient bites during recovery from anesthesia 

If the LMA is made of transparent PVC material, it usually means it is single-use. 

LMA Supreme 

One of the most commonly used LMAs is the LMA Supreme. 

Features include: 

  • Two tubes (airway + gastric) 
  • Transparent PVC material 
  • Disposable design 

Because of these features, it is widely used in clinical practice. 

LMA ProSeal 

Another very important LMA is the LMA ProSeal. 

This LMA: 

  • Has two tubes 
  • Is made of silicon material 
  • Is reusable 

Since it is silicon-based, it can be autoclaved and reused up to 40 times. 

LMA ProSeal is one of the most commonly used LMAs worldwide. 

It is especially preferred for: 

  • Daycare anesthesia 
  • Laparoscopic surgeries 
Ambu LMAs 

Next are LMAs manufactured by the Ambu company. 

These are usually colored LMAs, which helps in identifying them. 

Ambu Aura 40 

The Ambu Aura 40 is a first generation LMA. 

How do you identify it? 

Just check the number of tubes: 

  • One tube → First generation 

The name Aura 40 comes from the fact that it can be reused up to 40 times after sterilization. 

Ambu Aura Gain 

Another LMA from the same company is Ambu Aura Gain. 

This LMA has: 

  • One airway tube 
  • One gastric tube 

So it clearly belongs to the second generation LMAs. 

A simple way to remember it is: 

Ambu Aura Gain = Ambu Aura Green 

Since the LMA is green in color, it becomes easy to recall the name. 

I-gel LMA 

Another very important LMA for exams is the I-gel LMA. 

You can identify it easily because there is no pilot inflation balloon. 

So the obvious question is: 

How does the cuff inflate? 

The answer is that I-gel is made of thermo-elastic material. 

When inserted into the airway, this material responds to body temperature, expands slightly, and creates a seal around the laryngeal structures. 

Because of this property: 

  • No cuff inflation is required 
  • There is no pilot balloon 

So if the exam asks: 

Which LMA is a second generation cuffless LMA? 

The answer is I-gel LMA. 

Quick Revision 

Here’s a quick recap: 

First Generation LMAs 

  • LMA Classic 
  • LMA Unique 
  • LMA Flexible 
  • Ambu Aura 40 

Second Generation LMAs 

  • LMA Supreme 
  • LMA ProSeal 
  • Ambu Aura Gain 
  • I-gel LMA 

The easiest way to identify them in exams is to count the number of tubes: 

  • One tube → First generation 
  • Two tubes → Second generation 

Understanding the different types of LMAs and how to identify them is extremely important for exams like PDCET and DNB. Many questions are image-based, so simply remembering the number of tubes, material used, and special identifying features can help you quickly pick the right answer. If you focus on these small but important details, revising LMAs becomes much easier and far less confusing during exam preparation. 

If you want clearer, exam-oriented explanations of anesthesia topics, make sure to subscribe to Conceptual Anesthesia. Stay connected for more high-yield sessions. quick revisions, and practical exam tips that will help you prepare smarter for your upcoming exams. 

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