Guedels stages of anesthesia are seen classically with-
Ans. is 'a' i.e., Ether o GAs cause an irregularly descending depression of the CNS, i.e. higher functions are lost first and progressively lower area of the brain are involved.o In the spinal cord, lower segments are affected earlier than upper segments.o The vital centers located in the medulla are paralyzed the last as the depth of anaesthesia increases.o Guedel described four stages of ether anesthesia dividing the 111 stage into 4 planes.o With faster-acting GAs, these clear-cut stages are not seen nowadays.StageRespirationOcular movementPupil sizeReflexesBPMuscle tone HRUsesI Labour incision and minor operationsAnalgesiaNormalNormalNormalNormalNormalNormalNormalIINormal(At the end of this stage eyelid reflex is lost) Delirium (Excitement) Roving eyeballPartially Dilated JerkyIncreasedIncreasedIncreased N.L.IIISurgical1NormalRoving eyeballNormalEyelid reflex lostNormal or slightly decreasedNormal or Slightly reducedNormal}Most of the surgical operations2Slightly depressedEye fixedPartially dilatedCorneal and laryngeal reflex lostSlightly decreasedSlightly reducedSlightly increased 3MarkedlydepressedEye fixedPartiallydilatedLost light reflexDecreasedReducedIncreased 4Depressed with intercostal paralysis (only abd. respiration)Eye fixedFullydilatedAll reflexes lostDecreasedReducedIncreased IV Medullary Paralysis (overdose)respiratory arrestNo movementFixed and maximallydilatedLostNot recordableHypotoniaNot palpable o Stage I - From beginning of anesthetic inhalation to the loss of consciousness.o Stage II - From the loss of consciousness to the beginning of regular respiration.o Stage III - From the onset of regular respiration to the cessation of spontaneous breathing.Plane 1 - Roving eyeball, this plane ends when eyeball becomes fixed.Plane 2 - Loss of corneal and laryngeal reflex.Plane 3 - Pupil starts dilating, the light reflex is lost.Plane 4 - Intercostal paralysis and shallow respiration.o Stage IV - Cessation of spontaneous breathing to the failure of circulation and death.
Ether
Chloroform
Morphine
Nitrous oxide