Which of the following agents can be safely used in asthma? (Repeat)
Ans: B (Ketamine) Ref: Millers Anesthesia. 7th edn. & Ajay YadavExplanation:Causes Dissociative anesthesiaPhencyclidine derivativeNMDA receptor agonistAnesthetic propertiesOnset of Action: 30 - 60 secondsEarly regain of consciousness after 15-20 min due to RedistributionElimination half life: 2-3 hoursStrong analgesic propertyMetabolised in Liver and products excreted in urineNot a muscle relaxantPrimary site of action - Thalamo-neo-cortical projectionsCardiovascular systemIncreases arterial BPIncreases heart rate andIncreases cardiac outputIV agent of choice in ShockRespiratory systemPotent bronchodilatorGood induction agent for asthmaticsUpper airway reflexes remain largely intactIncreases salivatory and traeheo bronchial secretionsUsing glycopyrollate or atropine becomes necessaryCentral Nervous systemIncreases intracranial pressure and can precipitate seizuresEmergence reactions:These are seen at emergenceVivid dreamingIllusionsExtracorporeal experiences like lloatingExcitementConfusionEuphoriaFearHallucinations:Auditory and visual hallucinations (Most Common side effect of ketamine)Treated with benzodiazepineOther SystemsEye:Increase intraocular tensionPupils dilate moderatelyNystagmusGITIncreases intragastric pressureSalivary secretions increasedMuscluarIncreases muscle toneIncreased non-puposeful movementsDoseCan be given IV, IM, oral, rectal and intrathecal routeIV - 2 mg/kgIM- 5-10 mg/kgAdvantagesInduction agent of choice in:AsthmaticsShock (HYPOTENSION)Children ( Now Sevoflurance is DOC)Constrictive pericarditisCardiac tamponadeCan be used as Sole agentCan he used safely at remote places and in inexperienced hands since does not depress heart or respirationPreferred agent when patient is in Full Stomach (Preserves laryngo-pharyngeal reflexes)Contraindicated in:Head injuryICSOLEye injuryOpthal pathologyIschemic heart diseaseVascular aneurysmPsychiatric diseasesDrug addictsHypertensives
Thiopentone
Ketamine
Etomidate
Propofol
Anesthesia for Respiratory Disease