The document compares the commonly used inhalational anesthetics nitrous oxide, isoflurane, sevoflurane, halothane, and desflurane. It discusses their physical and chemical properties, effects on organ systems like cardiovascular, respiratory, central nervous system, hepatic, renal, and skeletal muscle. Nitrous oxide is also described in detail regarding its history of use, pharmacokinetics, and clinical applications.

1. INHALATIONAL ANAESTHETICS PRESENTER: Dr. Karthick. D MODERATOR: Dr Anand H.Kulkarni

3. ISOFLURANE SEVOFLURANE HALOTHANE

4. PHYSICAL AND CHEMICAL PROPERTIES OF INHALED ANAESTHETICS

5. BOILING POINT/ VAPOUR PRESSURE Boiling Point (° C ) Vapour pressure(mmHg) at 20°C HALOTHANE 50.2 243.3 ISOFLURANE 48.5 250 DESFLURANE 22.8 664 SEVOFLURANE 58.5 160

7. Physical properties (cont..) HALOTHANE Clear, non-explosive, non- inflammable liquid at room temperature, non-pungent odor ISOFLURANE Clear, non-inflammable liquid at room temperature, pungent ethereal odor. SEVOFLURANE Non pungent minimal odor DESFLURANE Pungent odor , irritating and unpleasant to inhale.

12. BLOOD GAS PARTITION COEFFICIENT HALOTHANE 2.5 ISOFLURANE 1.4 SEVOFLURANE 0.69 DESFLURANE 0.42

15. STABILITY HALOTHANE ISOFLURANE SEVOFLURANE ALKALI Some decomposition Stable Stable UV LIGHT Decomposes Stable Stable METAL May react Stable Stable

18. MINIMUM ALVEOLAR CONCENTRATION MAC in oxygen(%) Halothane 0.75 Enflurane 1.68 Isofurane 1.15 Sevoflurane 2 Desflurane 6 Nitrous oxide 105 Xenon 71

19. EFFECTS ON VARIOUS ORGAN SYSTEM

20. CARDIOVASCULAR SYSTEM

22. HEART RATE INHALATIONAL ANAESTHETIC HEART RATE HALOTHANE DECREASES ISOFLURANE/ENFLURANE/DESFLURANE/SEVOFLURANE INCREASES

24. SYSTEMIC VASCULAR RESISTANCE ISOFLURANE/DESFLURANE/SEVOFLURANE Decrease HALOTHANE No net effect NITROUS OXIDE No effect

28. RESPIRATORY SYSTEM

32. MINUTE VENTILATION

36. AIRWAY RESISTANCE

39. CENTRAL NERVOUS SYSTEM

42. CEREBRAL BLOOD FLOW

44. CBF / CMR

45. CEREBROSPINAL FLUID CSF PRODUCTION ABSORPTION HALOTHANE ↓ (30%) ↓ ISOFLURANE -- ↑ ENFLURANE ↑ ↓

47. HEPATIC SYSTEM

48. HEPATIC BLOOD FLOW Desflurane/ Sevoflurane ……. Similar to isoflurane BLOOD FLOW HALOTHANE ISOFLURANE PORTAL VEIN ↓ ↓ HEPATIC ARTERY ↓ ↑ NET FLOW ↓ Maintained

49. HEPATIC BLOOD FLOW

51. HEPATOTOXICITY -- depends on the quantity of drug getting metabolised TFA (Trifluoro acetic acid) HALOTHANE Large amounts ISOFLURANE/ ENFLURANE/ DESFLURANE Minute quantities SEVOFLURANE Nil

52. RENAL SYSTEM

57. FLOURIDE INDUCED NEPHROTOXICITY

59. SKELETAL MUSCLE EFFECTS

63. NITROUS OXIDE

66. N 2 O USAGE IN THE INITIAL DAYS

75. SECOND GAS EFFECT 19% oxygen 80% nitrous oxide 19% oxygen 40% nitrous oxide 32% nitrous oxide 1% second gas 7.6% oxygen 0.4% second gas 1% second gas Uptake of half of nitrous oxide Absorbed gases replaced by added ventilation

78. PHARMACODYNAMICS VARIOUS ORGAN SYSTEM EFFECTS

87. Thanks for your patient listening