Zen'ichiro Wajima

Changes in hemodynamic variables and catecholamine levels after rapid increase in sevoflurane or isoflurane concentration with or without nitrous oxide under endotracheal intubation

AbstractPurpose. Rapid increases in concentrations of isoflurane and desflurane in oxygen have been shown to increase sympathetic activity. The aim of this study was to determine whether concomitant administration of nitrous oxide would reduce these sympathomimetic effects of volatile anesthetics. Methods. Eighty healthy patients in whom the trachea was intubated and mechanically ventilated were given 15 min of anesthesia with either N2O (67%)-O2-sevoflurane (GOS), O2-sevoflurane (OS), N2O (67%)-O2-isoflurane (GOI), or O2-isoflurane (OI) (n = 20 per group). The inspired concen-tration of sevoflurane was 0.85% (0.5 minimum alveolar concentration [MAC]), and that of isoflurane was 0.6% (0.5 MAC). Fifteen minutes after endotracheal intubation, baseline and arterial blood sample data were obtained. Immediately after that, a sudden administration of 2.9 MAC volatile anesthetics was performed. Systolic and diastolic arterial pressures, heart rate, and end-tidal carbon dioxide concentration were obtained at 0.5, 1, 1.5, 2, 3, 4, and 5 min after that. To measure catecholamine levels, arterial blood samples were obtained 2 and 5 min after the trial started. Results. Except for the OI group, systolic and diastolic arterial pressure progressively decreased after the abrupt increase in the concentration of volatile anesthetics. Except for the OS group, the heart rate increased after the abrupt increase in the concentration of volatile anesthetics. In the OI group, the end-tidal concentration of carbon dioxide increased at 0.5 and 1 min, suggesting that a slight hyperdynamic state occurred. However, it decreased progressively after the abrupt increase in volatile anesthetic concentration in the other groups. Plasma norepinephrine levels increased progressively in all groups. Conclusion. Even if nitrous oxide was added to isoflurane or sevoflurane, the increase in heart rate could not be avoided. Contrary to previous reports, severe hyperdynamic circulation was not observed after a rapid increase in isoflurane concentration.

Severe lightning pain after subarachnoid block in a patient with neuropathic pain of central origin : which drug is best to treat the pain?

OBJECTIVE There have been many reports that spinal anesthesia induces severe lightning pain in the lower limbs of patients with phantom limb pain, tabes dorsalis, or causalgia. We report on a patient with neuropathic pain of central origin who showed newly developed severe lightning pain after therapeutic subarachnoid block (SAB). We performed SAB 16 times in this patient, and he complained of severe pain each time. We investigated which drug was best for treating such induced pain by administering various drugs to the patient. SETTING The patient was hospitalized for treatment and observation. PATIENT The patient was a 48-year-old man with neuropathic pain secondary to an incomplete spinal cord injury at the cervical segment. INTERVENTIONS Various drugs were administered for relieving the newly developed severe pain, and the effectiveness of these agents was compared. RESULTS AND CONCLUSIONS Intravenous thiopental, fentanyl, butorphanol, ketamine, midazolam, droperidol, and sevoflurane-oxygen anesthesia were quite effective. Intramuscular butorphanol was not effective. Intravenous physiologic saline and atropine sulfate as a placebo, intrathecal morphine hydrochloride, intravenous mexiletine, and lidocaine were ineffective. Intravenous thiopental (approximately 1 mg/kg) was thought to obtain the best pain relief because it stopped the pain quickly, the dose needed was subanesthetic, and there was no adverse effect.

Analgesia after upper abdominal surgery using extradural administration of a fixed dose of buprenorphine in combination with lignocaine given at two infusion rates: A comparative study

Background: Extradural administration of combinations of local anaesthetics and opioids are frequently employed for postoperative pain relief. There is a scarcity of data on the analgesic effects of variations of the dose of local anaesthetic drug admixed to a fixed dose of opioid.