When administered intrathecal ketamine shows local anesthetic effects in both animals and humans. Intrathecal ketamine when used as a sole agent (0.7-0.95 mg/kg) with or without epinephrine for intrathecal use, although produces motor and sensory block but the analgesia is inadequate and of short duration along with varied psychomimetic disturbances. When added to the intrathecal
Midazolam produces dose-dependent decrease in ventilation with 0.15 mg/kg IV producing effect similar to diazepam 0.3 mg/kg IV. Patients with chronic obstructive pulmonary disease experience even greater midazolam respiratory depression . Transient apnoea usually follows after rapid injection of large doses of midazolam (>0.15 mg/kg IV) especially in the presence of premedication with opioids. The
Diazepam metabolism is carried out by hepatic microsomal enzymes using an oxidative pathway of N-demethylation with the production of desmethyldiazepam, oxazepam, and to a lesser extent temazepam as metabolites. Desmethyl diazepam is metabolized more slowly than oxazepam and is only slightly less potent than diazepam. These metabolites contribute to the sustained effect of diazepam. The
Midazolam sedation is a useful intravenous adjunct to local or regional anesthesia for a variety of therapeutic and diagnostic procedures. Midazolam sedation in doses of 1.0 to 2.5 mg IV (onset within 30-60 sec, time to peak affect 3 to 5 minutes, duration of sedation 15 to 80 minutes) is effective for sedation. Titrated intravenous
There is an ongoing debate as to whether propofol EEG exhibits pro- or anticoagulant effects, and whether it should be used in patients with epilepsy. In a prospective study, Meyer et al documented propofol EEG as a sedative-hypnotic agent with anticonvulsant properties as shown by depression of spike-wave patterns in children with epilepsy and by
Ketamine analgesia produces intense analgesia at sub anesthetic doses and prompt induction of anesthesia when administered IV at higher doses. Ketamine analgesia has an analgesic action at many sites both centrally and peripherally. These actions are mediated via multiple receptor subtypes, including opioid, NMDA, kainate, and GABAA receptors. Ketamine also inhibits serotonin and dopamine reuptake.
For the Alveolar partial pressure of oxygen we see, Increasing the inspired concentration (F1) of an anesthetic agent increases the alveolar concentration (FA). A 75% nitrous oxide (N20) in oxygen mixture increases the FI/FA ratio of N2O. The amount of nitrous oxide absorbed will be greater than the nitrogen given out in the alveoli, hence
The effect of agonist drug of opoid group have a lot of impact as listed: Cough: The cough center in medulla is suppressed, leading to antitussive action. Pure agonists especially related with codeine have pronounced effect. Nausea and Vomiting: The emesis is usually due to direct stimulation of chemoreceptor trigger zone (CTZ) of area postrema of the
The midazolam dose must be carefully individualized. In elderly and debilitated patients, lower doses are required. The midazolam dose should further be adjusted according to the type and amount of premedication used. Excess doses or rapid IV administration may result in respiratory depression and/or arrest, particularly in elderly or debilitated patients. For IM use, midazolam
Propofol at common clinical concentrations-is potent ventilatory depressant and therefore it is sometimes common with the name propofol respiratory depression . The Propofol respiratory depression of ventilation is dose dependent. After induction of anesthesia with propofol apnoea occurs in 25% to 35% of patients which may persist till 3 minutes. It reduces tidal volume (by
