The effects of tramadol on postoperative shivering after sevoflurane and remifentanil anesthesia.

BACKGROUNDS: Remifentanil has been reported to cause post-anesthetic shivering (PAS). Higher doses of remifentanil reportedly induce more intense PAS. Tramadol, a synthetic opioid that acts at multiple sites, is considered to be an effective treatment for PAS, but the evidence for its therapeutic benefit after remifentanil anesthesia is limited. We investigated the effect of tramadol on the incidence of PAS after remifentanil anesthesia. METHODS: Sixty-three patients who had undergone upper abdominal surgery under general anesthesia were studied retrospectively. Tramadol was administered at induction of anesthesia. The patients were divided into four groups: HT(+), high dose remifentanil (1-1.5 µg/kg/min) with tramadol; HT(-), high dose remifentanil without tramadol; LT(+), low dose remifentanil (0.15-0.25 µg/kg/min) with tramadol; and LT(-), low dose remifentanil without tramadol. We recorded perioperative changes in nasopharyngeal temperature and episodes of PAS on emergence from anesthesia. RESULTS: The incidences of PAS in both tramadol treatment groups were significantly lower than the groups that did not receive tramadol. Nasopharyngeal temperature after surgery fell significantly more from baseline in the tramadol treatment groups compared with the non-treatment groups. CONCLUSION: Tramadol administered at induction of anesthesia appears to suppress PAS following remifentanil anesthesia.

Uptake of transition metal ions using liposomes containing dicetylphosphate as a ligand.

The uptake of Cu2+ was investigated using various types of liposomes composed of phosphatidylcholine (PC), cholesterol (Chol) and dicethylphosphate (DCP). DCP played a role as a ligand for Cu2+. Multilamellar vesicles (MLVs) were more effective for the uptake of Cu2+ compared to unilamellar vesicles prepared by the extrusion technique. The uptake efficiency of MLVs for Cu2+ was dependent on the molar ratio of DCP in MLVs. The uptake percent of Cu2+ was 92% using MLVs having a PC:DCP:Chol molar ratio of 4:3:3; 95% of the total vesicle Cu2+ was bound to DCP of the outer membrane surface of the MLVs, and the remaining 5% of the total Cu2+ was distributed into the interior side of the MLVs. MLVs having a PC:DCP:Chol molar ratio of 4:3:3 were also effective as separation media for Mn2+, Co2+, Ni2+ and Zn2+. The uptake efficiency of the MLVs for the transition-metal ions increased in the order Co2+ < Zn2+ < Ni2+ < Mn2+ < Cu2+.

[Anesthetic management of elderly patients aged 90 years or older].

The authors experienced 55 cases of anesthetic management in 52 elderly surgical patients, 14 men and 38 women, aged 90 to 101 years with an average of 92.1 +/- 2.1 years for the past ten years. Surgical procedures included 38 cases of orthopedic, 14 cases of general surgical and 3 cases of ophthalmic operations. Thirteen cases out of them were emergency. General, epidural, spinal, and local anesthesia were applied in 34 cases, 18 cases, 2 cases, and one case out of these elderly patients, respectively. These general anesthesia consisted of total intravenous anesthesia with propopol, fentanyl and ketamine in 27 cases, sevoflurane with nitrous oxide in 4 cases, isoflurane with nitrous oxide or air in 2 cases, and thiopental anesthesia in one case. The elderly patients had past history of heart disease, dementia, hypertension, cerebral infarction/hemorrhage, diabetes mellitus and others. Their preoperative examinations revealed anemia, hypoproteinemia, renal hypofunction, serum electrolytes imbalance, and others. Vasopessors were given to 42% of the patients during anesthesia and surgery. Their postoperative complications included myocardial infarction, paroxysmal atrial fibrillation, hypotension following anemia, transient hemiparesis, delirium and so on. Two patients developed myocardial infarction postoperatively and died thereafter. The authors suggest that appropriate anesthetic management for elderly patients aged 90 years or older requires proper preoperative evaluation, sufficient vigilance of hemodynamics with direct arterial pressure measurement, reliable preparation of medical agents, and awareness of impairment of circulatory function and others by aging.