Anaesthesia Notes for Pg

45 NOTES TO PG —Dr. Ankit Yadavendra, M.B.B.S., Dr.V.M.G.M.C., Solapur

26-ANAESTHESIA hyperpathia=hyperesthesia+ allodynia+ hyperalgesia hypotensive anaesth-orthopedic Sx ETT thyromental dist>6.5cm sternomental dist>12.5cm adeq mouth opening>3finger breadth(pt) movem of Cx spine double lumen ETT abs indication-resection of bronchopleural fistula Mx of preexisting drug Rx herbal medicine, smoking-stop 6-8w bef OCP-stop 4w bef MAOI-stop 3w bef clopidogrel-stop 5-7d bef oral anticoagulant(warfarin)-stop 3-5d bef Li-stop 2d bef newer MAOI(selegiline)-stop 1d bef LMW heparin-stop 12-14h bef NPO-solid-6h, liquid-4h, BF infant-solid(milk)-4h,liquid-2h insulin/oral hypoglycemia-omit morning dose antiHTN(βadr antag)-continue(except ACEI,ARB) aspirin-75mg-continue(except closed space Sx), >75mg-stop 3-5d bef antianginal, anticonvulsive, levodopa, only P pill, steroid-continue abtc-1st-induction anaesth(½-1h bef incision), 2nd-Sx>6h anaesth machine(1st-1917) Boyle continuous flow anaesth machine high pressure system cylinder-Mb steel alloy, MRI room-Al size↑-A→ H typeE O2 cylinder=660l O2 typeD O2 cylinder=470l O2 gas-colour O2-Black Body, white shoulder N2O-blue N2-black CO2-grey air-grey body, black&white quartered shoulder cyclOpRopANE-OrANgE

He-brown entonox(50%O2+50%N2O)-Blue Body, blue&white shoulder Halothane-Red Enflurane-Orange Isoflurane-Purple Sevoflurane-Yellow(HE IS ROPY) acetylene-maroon H2-red ARGoN-dARk GReeN ChLOrinE-yELLOw ethylene-purple gas-pin index air-1,5 O2-2,5 N2O-3,5 CO2(>7.5%)-1,6 CO2( Sevoflurane(2.0%)> Ether(1.92%)> Enflurane(1.68%)> Isoflurane(1.15%)> Halothane(0.74%)> Methoxyflurane(0.16%) Desflurane-max-speed of onset&recovery, min-B:G partit coeff, bld solubility, diffusion coeff Methoxyflurane-vice versa elective Sx

preO2(3-4min)+IV induct+SMR→ IPPV(bag&mask)→ ETT emergency(full stom) Sx preO2(3-4min)+IV induct+SMR(SCh/rocuronium)→ no IPPV→ pressure on cricoid cartilage(Sellick manoevre)→ cuffed ETT Brewer Luckhardt reflex intense pain laryngospasm reflex body movement tachypnoea preoperative digitalization prevents-intraoperative heart failure, postoperative heart failure, supraventricular arrhythmia morphine premedication=IM 10mg postanasthetic shivering ↑metab rate by=4time position in suspected air embolism-head low, rt side up inf alveolar n infiltration at-3rd molar landmark for lingual site block-mandibular foramen peak pl conc of LA-intrapleural> intercostal> lumbar> epidural> brachial plex> s/c neuraxial block spinal needl-pencil tip(Sprotte, Whitacre), nonpencil tip(Quincke) ↓dose-old age, preg, abd tm lingual n block-angle of mandible postspinal headache last for=7-8d preanesth med atropine-↑CNS hyoscine(scopolamine)-↓CNS glycopyrrolate-no effect pain on IV inj-etomidate> propofol> methohexitone> thiopentone> ketamine(0) speed of recovery-propofol> methohexital> thiopentone> midazolam DRUG General anaesthetic inhalational volatile liquid-chloroform, diethyl ether, ethylCl, trichloroethylene flurane-methoxyflurane, sevoflurane, halothane, enflurane, isoflurane, desflurane gas-cyclopropane, N2O intravenous barbiturate-thiopentone, methohexital non-barb BDZ-midazolam, diazepam

phencyclidine-ketamine steroid-pregnenolone etomidate, propofol IV anaesthetic Thiopentone(1934)(↓all except HR) yellow, amorphous powder, 6%anhydrous Na2CO3, prepared&stored in N2, pH=10.5-11, S-↑Solubility, metab in liver, pt regains consciousness by redistribution, microsomal enzyme inducer, releases histamine CVS-periph vasodilator, ↓BP, ↑HR, ↑myocard contractility RS-↓RR CNS-cerebral vasoconstrictor, ↓cerebral bld flow, ↓ICP, ↓cerebral metab rate, ↓sz pain-↓threshold c/i-a/c interm porphyria, variegate porphyria dose-1-6mth infant=7mg/kg, children=5- 6mg/kg, adult=3-5mg/kg(2.5%) onset timevisual), amnesia eye-↑IOP GIT-↑salivary secretion, ↑IAP pain-↑threshold c/i-HTN, CAD, aortic aneurysm, head inj, space occupying lesion brain, epilepsy, glaucoma dose=4-10mg/kg IM, 1-2mg/kg IV PROpofol(1,6-diisopropylphenol)(opposite of ketamine) milky white liq, soyabean oil, glycerol, egg lecithin, metab-liver(70%),lung(30%), highly PROt bound CVS-↓BP, ↓HR RS-↓RR, ↓upper airway reflex CNS-↓ICP, ↓cerebral metab rate, ↓sz GIT-↓vomiting antipruritic, antioxidant neuroleptic analgesia=droperidol(2.5mg)+ fentanyl(50μg) neuroleptic anaesth=droperidol(2.5mg)+ fentanyl(50μg)+ N2O Inhalational anaesthetic

Ether pungent, irritating to airway, inflammable RS-bronchodil, preserves ciliary activity pain-↑threshold m-relax hyperglycemia c/i-cautery Ethylene c/i-cautery Cyclopropane fast induction c/i-cautery N2O(laughing gas) prepared by heating NH4NO3 at 250°C, 1.5time heavy than air, 35time more soluble in bld than N2, irrevers oxidises Co atom of vitB12& ↓methionine synthetase&thymidylate synthetase→ megaloblast anem&periph neuropathy, nausea,vomiting, teratogenic, not metab by body CVS-↑pulm vasc resistance RS-↓carotid body hypoxic drive CNS-↑ICP, ↑cerebral metab rate pain-↑threshold c/i-pulm HTN, venous air embolism, pneumothorax, lung cyst, intracran Sx, tympanoplasty, vitreoret Sx Methoxyflurane(3F atom) vasopressor resist high output ren fail, boiling pt>75°C, hepatitis Halothane shivering, hepatitis, centrilobular necrosis CVS-sensitises heart to catecholamine, ↓BP RS-bronchodil CNS-↓hypoxi drive, cerebral vasodil, ↑ICP, potentiat compet NM blocker GIT-↓hep bld flow&portal bld flow, fatal rate with hepatitis=20-40% uterus-relax pain-poor analgesic c/i-↑ICP, liver dysfn, pheochromocytoma, malign hyperthermia, cardiac arrhythmia Enflurane tonic-clonic sz c/i-Epilepsy, renal ds, malign hyperthemia Isoflurane pungent, coronary steal synd CVS-periph vasodilator, ↓BP, ↑HR CNS-↑ICP c/i-severe hypovolemia, malign hyperthermia

Desflurane pungent, eliminat by lung CVS-↑BP, ↑HR RS-irritant to airway, breath holding, coughing, laryngospasm GIT-salivatory c/i-child, malign hyperthermia Sevoflurane(7F atom) sweet smelling CVS-↑QT interval CNS-↑sz, ↑ICP Muscle relaxant centrally acting-BDZ, baclofen, mephenesin, tizanidine, carisoprodol, chlorzoxazone, methocarbamol, orphenadrine, cyclobenzaprine noncompet depol-SCh compet nondepol benzylisoquinolium(curium) short act(10-20min)-mivacurium interm act(20-50min)-cisatracurium, atracurium long act(60-120min)-doxacurium, dtubocurarine, gallamine ammoniosteroid(curonium) short act-ropacuronium interm act-rocuronium, vecuronium long act-Pancuronium, Pipecuronium sugammadex=vecuronium+ pancuronium+ rocuronium SuccinylcHoline(suxamethonium)(↑all) noncompet, depolarising, no fade on train of 4 stimulus, Hist release, ganglion stimul, ↑K+ level by 0.5mEq/l, RF CVS-↑BP CNS-↑ICP GIT-↑IAP, ↑LES tone eye-↑IOP c/i-stroke, cerebral palsy, burn, spinal cord inj, m dystrophy dose=2mg/kg onset