Intracranial Pressure IV

Meperidine was initially synthesized as an anticholinergic agent but was soon discovered to have analgesic properties. Although meperidine's anticholinergic effects were demonstrated in vivo, the anticholinergic effects on the biliary and renal tracts have not been demonstrated in vivo. Studies have clearly demonstrated that meperidine is no more efficacious in treating biliary or renal tract spasm than comparative mu opioids. The initial studies demonstrating the analgesic efficacy of meperidine were mostly case reports and not double-blind, randomized, controlled trials in specific populations. Subsequent comparative studies failed to demonstrate any advantages of meperidine over comparable doses of other analgesics. Meperidine was portrayed in practice and teaching as having unique clinical advantages. The analgesic effects of meperidine are not pronounced, and, in addition, meperidine use is complicated by unique side effects including serotonergic crisis and normeperidine toxicity. Meperidine's poor efficacy, toxicity, and multiple drug interactions have resulted in a movement to replace meperidine with more efficacious and less toxic opioid analgesics.

Meperidine: a critical review.

Analysis of 24 cases of enflurane anesthesia-associated hepatic injury shows that the clinical, biochemical, and histologic features are similar to those seen with halothane- and methoxyflurane-related hepatitis. Postoperative fever was the presenting symptom in 19 patients. Jaundice occurred in 19 patients after a mean latent period of 8 days. Sixteen patients had been previously exposed to enflurane or halothane, and the latent period from exposure to the onset of symptoms or jaundice was shortened in these patients. There were five fatalities among the entire group. Liver biopsy most characteristically showed centrilobular necrosis, occasionally with ballooning degeneration and fatty change. The presumed mechanism of injury is metabolic idiosyncracy, and prior exposure to a haloalkane anesthetic may increase the risk of hepatic injury after enflurane administration.

Enflurane hepatotoxicity. A clinicopathologic study of 24 cases.

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Ventilation/Blood Flow and Gas Exchange

Enflurane sedation and anaesthesia in healthy fit subjects reduced ventilation and the response to carbon dioxide, hypoxaemia and a low dose of doxapram, all in a dose-related fashion. Comparing the three chemoreflexes tested, the response to hypoxaemia and doxapram were the more profoundly impaired; they were nearly totally abolished by anaesthesia. These effects of enflurane on chemoreflex activities are qualitatively similar to those previously observed with halothane.

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Ventilation and chemoreflexes during enflurane sedation and anaesthesia in man

Compound 347 (CHF2-O-CF2-CHFCl), a new non-explosive fluorinated ether, was administered with nitrous oxide–oxygen to 100 patients for major elective abdominal operations. This agent provided rapid, pleasant induction and emergence and adequate hypnosis, analgesia and muscular relaxation, with minim

Clinical and laboratory evaluation of a new inhalation agent: compound 347 (CHF2-O-CF2-CHF Cl).

ORE THAN 20 years ago, Robbins1 studM ied the anesthetic effect of fluorinated hydrocarbons and found that those with a low boiling point produced convulsive movements. The anesthetic potency and recovery time from anesthesia could be increased by fluorinated compounds with a higher boiling point. The addition of bromine appeared to increase the safety margin of such an anesthetic compound and also increased the potency. The inclusion of several halogen atoms into a compound substantially reduced the flammability range. The use of fluorine for halogenation did not decrease the volatility of an agent, but at least one hydrogen atom appeared to be required to ensure anesthetic potency.

Ethrane (Compound 347) anesthesia: a clinical and laboratory review of 700 cases.

Circulatory and Respiratory Response to Tilt With Pentazocine (Win 20, 228), Droperidol (R4749), Droperidol-Fentanyl (Innovar), and Methotrimeprazine in Normal Healthy Male Subjects

Double-blind study of methotrimeprazine, morphine, and meperidine for preanesthetic medication.

The effects of high spinal analgesia and hyperventilation on the incidence of epinephrine-provoked cardiac arrhythmias were reorded electrocardiographcally on dogs during anaesthesia with 1 per cent rnethoxyflurane and with 2 per cent halothane. It was obvious that neither spinal analgesia nor hyperventilation protects the heart of the dog from the potentially lethal effect of epinephrine when a stable level of anaesthesia is accomplished with methoxyflurane. During halothane anaesthesia, the epinephrine challenge is lethal in most instances.

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Jacob S. Israel

Papers

Clinical and laboratory evaluation of a new inhalation agent: compound 347 (CHF2-O-CF2-CHF Cl).

Ethrane (Compound 347) anesthesia: a clinical and laboratory review of 700 cases.

Circulatory and Respiratory Response to Tilt With Pentazocine (Win 20, 228), Droperidol (R4749), Droperidol-Fentanyl (Innovar), and Methotrimeprazine in Normal Healthy Male Subjects

Double-blind study of methotrimeprazine, morphine, and meperidine for preanesthetic medication.

The effect of sympathetic blockade or hyperventilation on epinephrine-induced cardiac arrhythmias during anaesthesia with halothane and methoxyflurane