Halothane
• Causes bradycardia with vagomimetic effect.
• It is a drug that increases the sensitivity of the heart to catecholamines and causes (at most) ARrhythmia.
• It is the only modern inhalation anesthetic containing bromine.
• It decreases cardiac output by dose-dependent decrease in cardiac contractility and causes hypotension.
• Depresses breathing; Tidal volume decreases and velocity increases.
• It is preferred in asthmatics as it causes bronchial dilatation.
• It is the general anesthetic drug that can cause the most MALIGN HYPERTHERMIA.
• It causes HYPOTHERMIA.
• Increases CSF pressure.
• It decreases hepatic and renal blood flow.
• Decreases glomerular filtration rate.
• It is the most hepatotoxic agent. Obesity, female gender, and repeated doses increase the incidence of complete hepatic necrosis. It is not toxic to children.
• Since it reduces uterine contraction with a central effect, it causes postpartum bleeding.
Enflurane
• It lowers the average blood pressure and increases the heart rate.
• It makes bronchodilation and airway reflexes are preserved.
• It should not be used in patients with epilepsy, as it increases the tendency to convulsions.
Isoflurane
• It has a strong vasodilator effect and causes hypotension accordingly.
• It causes bronchodilation, does not have an arrhythmogenic effect; so it can be used in asthmatic patients.
• It reduces cerebral oxygen consumption and is preferred in neurosurgery because it does not increase intracranial pressure.
• Hepatotoxic and nephrotoxic effect potential is very low.
methoxyflurane
• It is the strongest general anesthetic (the lowest MAC value).
• Does not increase sensitivity to catecholamines
• It is nephrotoxic.
• It causes diabetes insipidus and acute kidney toxicity due to fluorine released during its metabolism (ca-oxalate stones are formed in the kidney).
Sevoflurane
• It is the least metabolized inhalation anesthetic in the liver.
• It does not increase catecholamine sensitivity in the myocardium (like nitrous oxide) and does not cause tachycardia.
• It depresses respiration and causes bronchodilation.
• Since it does not irritate the respiratory tract, it can be used in the induction of anesthesia, especially in children.
• It is used safely in pheochromocytoma.
• It has no organotoxicity. However, its metabolites and the resulting fluorine ion are nephrotoxic. For this reason, it should not be preferred in renal failure.
Desflurane
Induction and recovery times are the fastest among available inhalation anesthetics.
May cause laryngospasm by irritating the airway. Therefore, it is not suitable for mask induction.
It is gaseous at room temperature.
The vapor pressure is too high. It is therefore supplied with a special heater and pressure vaporizers.
Carbon dioxide is released as a result of interaction with dry baralyme.
It is excreted from the lungs almost without being metabolized.
Nitrous Protoxide (Nitrous Oxide / N2O)
• It is a good analgesic but a weak anesthetic (general anesthetic potency is weak).
• The incidence of postoperative nausea-vomiting is high, especially after 1 hour use.
• It has no toxic effect on liver and kidney.
• It has a funny effect.
• It does not cause malignant hyperthermia.
• Dose-dependent direct depressive effect on the myocardium; however, this is balanced by the effect of the sympathetic stimulant.
• Increases respiratory rate (tachypnea) and decreases tidal volume.
• It does not cause significant depression on respiratory and cardiovascular systems.
• It has no muscle relaxant effect, it is used safely since it will not relax the uterus during labor (methoxyflurane can also be used).
• Shows anticonvulsant effect.
• It causes a slight increase in intracranial pressure by increasing cerebral blood flow and cerebral blood volume.
• During anesthesia, dreams with a sexual content may be seen.
• It can cause methemoglobinemia.
• It inhibits vitamin B12 dependent enzymes and may cause bone marrow depression.
• It is teratogenic.
• Diffusion hypoxia may occur during sobriety.
• It tends to accumulate in the gas-containing parts of the body, it may cause volume expansion.
• It can easily diffuse into closed air spaces such as the middle ear, intestine, cranial air sinuses, pneumoperitoneum (eg, laparoscopic procedures), pneumothorax, and gas bubbles created during ocular surgery.
• This results in an increase in the volume of the area (intestinal distension) or an increase in pressure (eg in the eye or middle ear).
• Like CO2, it causes destruction of the ozone layer in the upper atmosphere.
• A 50:50 mixture of oxygen and nitrous oxide (entonox) is useful in procedures such as pediatric dentistry, obstetric analgesia, burn dressings.
Xenon
• It is an inert gas. It remains after the evaporation of the liquid-air components. It is found in very low concentration in the atmosphere.
• Blood: the anesthetic agent with the lowest gas partition coefficient. Provides rapid induction and awakening.
• Its MAC value is 71% and it has analgesic properties as well as anesthetic properties. This effect is mediated by inhibition of N-methyl-D-aspartate receptors in the central nervous system.
• It is not metabolized, it is excreted from the lungs unchanged.
• Its effects on cardiovascular, neuronal and respiratory systems are minimal, it is not a triggering agent for malignant hyperthermia.
• Its use is limited due to its high cost.
