Ketamine

General

As an almost ideal emergency drug, ketamine is sold under the trade name Ketanest-S®. It has an exceptionally good pain-relieving effect through what is known as dissociative anesthesia, which puts the patient in a trance state, but in which breathing and vital reflexes are preserved. For these reasons, it is often used to rescue difficult-to-reach patients who are trapped, for example.

Mode of action

The NMDA receptor complex is not competitively blocked by ketamine, which leads to dissociative anesthesia (i.e. the functional separation between the thalamocortical and limbic systems). Also a pronounced pain relief, one amnesia, Cataplesia and a superficial anesthetic with increased muscle tone and broncholysis. By Beta blockers possible circulatory reactions can be treated. Certain opiate receptors, which can cause respiratory depression and addiction when stimulated, are not occupied by ketamine.

application areas

Ketamine is used for the most severe pain in emergency medicine and is also effective, for example Multiple trauma (multiple severe injuries) successfully. Even with patients who cannot be reached because they are trapped or an acute one Asthma attack treatment with ketamine can ensure respiratory function.

Contraindications

Ketamine may not be used for heart disease, high blood pressure, Aortic aneurysm, Pheochromocytoma, Eclampsia, Hyperthyroidismcausing eye injuries, glaucoma (glaucoma, increased intraocular pressure), threatened uterine rupture, umbilical cord prolapse or psychiatric illness.

dosage

As an injectable narcotic with a duration of action of approx.10 minutes, ketamine is used at a dosage of 1-2 mg / kg and begins to work after about 30 seconds.
If analgesic sedation is to be carried out, up to 0.25 mg / kg are administered and for induction of anesthesia up to 1 mg / kg, as well as up to 1.5 mg / kg for status asthmaticus.
The intramuscular injection has also proven itself in use, even if the onset of action is delayed here by 5 minutes, but the effect also lasts for up to 30 minutes.

Side effects of ketamine

Both the brain and heart need more oxygen when taking ketamine. There may be an increase in intracranial pressure and heart rate, as well Blood pressure rise regularly. These body reactions to ketamine can be beneficial and desirable in hypovolemic shock (i.e. after major blood loss).
If there is an overdose of ketamine, myocardial depression and blood pressure drop, as well as an increase in lung resistance, are possible.

The patient has a negative perception of the unpleasant dreams associated with ketamine during the anesthesia, which can increasingly be reinforced by acoustic stimuli in the introductory phase of the anesthesia.
In children and the elderly, these uncomfortable dreams were observed less or not at all.
Due to the psychologically impairing dreams, additional medication with midazolam or Diazepam highly recommended.
The side effect of increased salivation (hypersalivation), which is mainly observed in children, can be remedied by giving atropine.
In aggressive personalities, ketamine administration can lead to increased psychomotor restlessness and alcoholics may need higher doses due to the faster breakdown of ketamine. Motor restlessness and aggression are also possible here.

Strict contraindications of ketamine:
Absolute and urgently to be considered contraindications to the administration of ketamine are hypertension (high blood pressure), KHK (Coronary heart disease), Myocardial infarction (Heart attack), as well as penetrating eye injury (tear, etc.).