Anasthesia 1 - PAC

1. Past Medical History & Treatment Plan Prior to Surgery

• Hypertension
• Continue all antihypertensives until day of surgery.
• Except ACE-I & ARBs (risk of severe hypotension if stopped).
• For minimal blood loss surgeries → ACEI & ARBs can be continued.

• Diabetes Mellitus
• Stop OHAs & insulin on day of surgery (risk of hypoglycemia).
• Stop SGLT-2 inhibitors (risk of euglycemic ketoacidosis)
• 24 hours prior → Elective Sx
• 72 hrs prior → Intermediate to high risk Sx
• Intra-operatively: Start regular short-acting insulin.

• Epilepsy
• Continue antiepileptics until day of surgery.
• Hypoxia, hypercarbia, acidosis — can precipitate seizures.
• Obtain baseline LFTs.

• Thyroid Disorder
• Continue thyroid medications until day of surgery.
• Hypothyroidism — delayed recovery due to decreased BMR.
• Hyperthyroidism — continue drugs to prevent thyroid storm (tachycardia, SVT,Temp ).

• Psychiatric Problems
• Continue antipsychotics.
• Exception:
• Stop MAO inhibitors 3 weeks prior
• interact with meperidine → hypertensive crisis
• Lithium/Mg²⁺:
• Stop 24-48 h prior
• if using long-acting muscle relaxants
• Eg: Pancuronium
• due to prolonged action
• Can continue
• if using short-acting muscle relaxants
• mivacurium
• atracurium

2. Medications & Treatment Plan Prior to Surgery

• Oral Contraceptive Pills
• Estrogen → ↑ DVT risk.
• Continue if low risk
• young, immediate mobilization
• Stop if high risk
• old age, long bone fractures, bed-rest
• Progesterone → no risk.

• Herbal Medicine
• Check LFTs.
• If abnormal → delay surgery 1-2 weeks.

• Anti-tubercular Therapy (ATT)
• Continue (stopping → ↑ MDR TB risk).
• Check LFTs (enzyme inducers).

• Sildenafil
• Stop 24-48 hours prior (risk of hypotension).

• Diuretics
• Stop all diuretics (risk: electrolyte imbalance/hypotension).
• Exception: thiazides.

• Anticoagulants
• Discontinue before regional anasthesia
• prevent bleeding, nerve compression, permanent damage
• Esp. in closed cavity spaces → vertebral column, orbit, cranium
• Aspirin :
• Stop 3 days prior if high bleeding risk.
• Warfarin / Clopidogrel:
• Stop 5-7 days prior.
• Bridging with LMWH:
• LMWH → duration 12 hrs
• Prophylactic dose — stop 12 hrs prior.
• Therapeutic dose — stop 24 hrs prior.
• Regular heparin
• stop 6 hrs before.
• Topical anesthesia
• continue anticoagulants.

3. Personal History

• Smoking
• Stop 3-4 weeks prior (ideal: 6-8 weeks).
• ↑ risk bronchospasm
• Clinical:
• sudden tachycardia,
• HTN,
• ↑ airway resistance,
• wheeze,
• EtCO₂ "shark fin pattern".
• Treatment: bronchodilators.
• ↑ risk laryngospasm on extubation
• Clinical:
• stridor f/b rapid ↓ SpO₂,
• paradoxical chest movement,
• no air entry.
• Treatment:
• 100% O₂, propofol (DOC).
• If uncontrolled: add succinylcholine.

• Alcohol
• Stop 24-48 hours prior.

• Tobacco Chewing
• May cause difficult intubation (restricted mouth opening).

4. Family & Allergy History

Allergy History

• Can cause anaphylactic shock
• Histamine: vasodilator & bronchoconstrictor

• Etiology
• (most → least)
• Antibiotics > Latex > Muscle relaxants (Atracurium, Sugammadex) > Local anaesthetics.

• Presentation:
• sudden tachycardia,
• hypotension,
• wheeze (↑ airway resistance),
• edema (lips/face/airway).

• Management:
• Adrenaline (DOC):
• 1 ml = 1 mg (if 1:1000)
• IV:
• Dose: 1ml of 10,000 IV ?
• IM/SC:
• 0.5 ml of 1:1000.
• Hydrocortisone.
• Adequate fluids.

5. Airway Examination

• Risk factors for difficult intubation:
• History of difficult intubation.
• Airway anomalies.

• Predictors of DI:
• Mnemonic P OBESE:
• Pregnancy,
• Obesity,
• Bearded,
• Elderly,
• Short,
• Edentulous.
• Long upper incisors.
• High arched palate.
• Inability to protrude lower jaw.
• Small mouth opening.

• Measurements:
• Mouth opening:
• Finger breadth technique
• normal = 3 fingers.

• Atlanto-occipital/C-spine mobility:
• normal 12 - 35°.
• Neck circumference
• > 43 cm → Difficult Intubation risk.
• Thyromental distance:
• Normal >6.5 cm.
• Sternomental distance:
• Normal > 13 cm

• Mallampatti Scoring



Grade	Structure Seen
Grade 0	• Clear glottic opening with large epiglottis • Difficult intubation
Grade I	• Uvula hanging freely
Grade II	• Tip of uvula not visible
Grade III	• Half of uvula not visible
Grade IV ↳ (Introduced by Sampson Young)	• Only hard palate visible

• Difficult intubation: Grades 0, III & IV

ASA Grading (INICET)

• Minimum acceptable Hb before elective surgery:

Parameter	General	With comorbidities	Critically ill
Hb (g/dl)	≥8	≥10	≥12

• Minimum platelet counts:

Procedure	Count
Central line	20,000 - 30,000 may be enough
Central line/ liver biopsy/ Invasive most major procedures	50,000
Peripheral neuraxial block	80,000
Central neuraxial block/ Neurosurgery / Eye Surgery	1 lakh

ECHO/ECG criteria (INICET):

• ECHO
• Not done as routine

• Mandatory ECHO:
• Dyspnoea unknown origin,
• HF with worsening dyspnoea.

• May do ECHO:
• Past LV dysfunction not evaluated in 1 year.

• Mandatory ECG:
• H/o IHD,
• significant arrhythmia,
• PAD,
• CVD,
• significant structural disease.

• May do ECG:
• Major surgery in asymptomatic without coronary disease.

• ECG Not done:
• Asymptomatic,
• low risk surgery.

7. Risk Stratification

Cardiac Risk (ACC/AHA)

• Emergency
• → proceed.

• Elective:
• ACS,
• Decompensated HF,
• Significant arrhythmias,
• Valvular disease.

MI Risk Points:

• When to do stress testing before Sx ?
• Functional capacity < 4 METS

• Surgery after stenting:
• Bare metal stent — wait 1 month.
• Drug eluting stent — wait 6 months.

• Infective Endocarditis prophylaxis:
• PROPHYLAXIS NOT NEEDED IN ASD

• Dental procedures.

• Invasive procedures: 
• Tonsillectomy, Adenoidectomy.

Pulmonary Risk:

• Patient related:
• old age,
• ASA > 2
• smoker,
• Functionally dependent COPD
• CHF
• Alcohol
• abnormal CXR.

• Procedure related:
• General anasthesia
• Emergency surgery.
• Thoracic/abdominal/Neuro/Head and neck/Vascular surgery,
• aortic aneurysm repair,
• Perioperative transfusion

• Labs:
• Albumin <3.5 g/dL,
• BUN > 7.5 mmoL/L (> 21 mg/dL)
• CXR abnormalities.

8. Pre-operative Instructions

Pre-medications:

• Anxiolytic:
• short-acting benzodiazepines (midazolam).

• Anti-emetic:
• ondansetron.
• For females, h/o motion sickness, non smoker, opioids

• Anti-sialagogues:
• atropine/glycopyrrolate (anti cholinergics)
• children,
• intellectual disability,
• head & neck surgery

• Analgesia:
• short-acting opioids (fentanyl).

• Antibiotics:
• cephalosporin for cardiac surgery.

Fasting guidelines:

• NPO/NBM (Nil By Mouth)
• Adults:
• 6-8 hrs.
• Children:
• Clear liquids — 2 hrs
• Solute loading — 2 hrs
• Breast milk — 4 hrs.
• Non-human milk, solids — 6 hrs.
• Heavy fatty meal — 8 hrs.

Clearance for Sx

• Reserve Blood

• Prepare bowel and bladder

• Consent