12/3/2023 0 Comments Side effect anesthesiaAdditionally, as respiration is maintained through the induction phase until the onset of neuromuscular paralysis, oxygenation may be more effectively maintained 30. In a critically ill patient, ketamine provides cardiovascular stability, because it exerts sympathomimetic action in patients with an intact autonomic nervous system, which compensates for its direct negative inotropic effect on an isolated heart 29. This is longer than the arm‐brain circulation time desired for “rapid” unconsciousness. ![]() In addition, the safety and the process of anesthesia cannot be disrupted by the prehospital conditions 27, 28.Īn induction dose of ketamine 1–2 mg/kg IV induces dissociative anesthesia 1–2 min after IV injection. The overall success of rapid sequence induction (RSI) is dependent on the appropriate selection of induction and neuromuscular blocking agents to provide optimal intubation conditions 24, 26. Prehospital intubation is undertaken in a less controlled environment than in hospital. On rectal administration, peak‐serum concentrations are reached after 40 min 21, 22, 23. A high inter‐individual peak‐plasma concentration, likely to be due to swallowing and drug draining out of the nose, results in a variable effect 19, 20. These properties combined with the ease of access make this route appealing 18. This results in a rapid systemic absorption. Intranasal administration (IN) is facilitated by the large surface, uniform temperature, high permeability, and extensive vascularization of the nasal mucosa. 1–5 min IV), and the clinical response may be unpredictable. ![]() The peak effect was delayed (15–30 min vs. Recently, the first report of a lozenge containing ketamine 25 mg was published. A similar antiemetic effect is seen with the concomitant use of propofol 17. Coadministered ondansetron reduces the incidence of emesis in children (number needed to treat = 9) 16. Compared to IV, the IM route is associated with longer recovery times and a higher rate of vomiting 15. It is safe and predictable although painful to give 12, 13, 14. The IM route has been used for decades 11. The onset of anesthesia is slightly later with IO as compared with IV injection (71 vs. Improved tools for intraosseous (IO) access have made this route of administration safe 8, 9. The incidence of side effects is comparable at equal plasma concentrations 6, although some report fewer side effects and a shorter recovery with S‐(+)‐ketamine. ![]() S‐(+)‐ketamine is available in two formulations: 5 and 25 mg/mL 6. The S‐(+)‐ketamine solution is preservative free, which may decrease neurotoxicity. The 50 mg/mL solution is commonly stocked because it can be easily injected IV and intramuscular (IM). Racemic ketamine is available in three different concentrations: 10, 50, and 100 mg/mL. S‐(+)‐ketamine is available only in some countries, for example, in the European Union 5, thus if not mentioned otherwise, ketamine in this text refers to the racemic ketamine and intravenous (IV) administration. The S‐(+)‐isomer is two‐fold more effective and longer acting than the racemic mixture of both isomers hence, half of the dosage is required with S‐(+) as compared with the racemic ketamine 2, 3, 4. Ketamine contains an asymmetrical carbon atom this leads to two optical isomers: the S‐(+) and the R‐(‐)isomer, which have different pharmacologic profiles 1. ![]() Racemic and S‐(+)‐Ketamine: Differences in Effects and Dosing
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