A comparison of alfentanil requirements in European and Asian patients during general anaesthesia

Isolation of Mitochondria-Associated ER Membranes (MAMs), Synaptic MAMs, and Glycosphingolipid Enriched Microdomains (GEMs) from Brain Tissues and Neuronal Cells

Subcellular fractionation is a valuable procedure in cell biology to separate and purify various subcellular constituents from one another, i.e., nucleus, cytosol, membranes/organelles, and cytoskeleton. The procedure relies on the use of differential centrifugation of cell and tissue homogenates. Fractionated subcellular organelles may be subjected to additional purification steps that enable the isolation of specific cellular sub-compartments, including interorganellar membrane contact sites. Here we outline a protocol tailored to the isolation of mitochondria, mitochondria-associated ER membranes (MAMs), and glycosphingolipid enriched microdomains (GEMs) from the adult mouse brain, primary neurospheres, and murine embryonic fibroblasts (MEFs). We also provide a detailed protocol for the purification of synaptosomes and their corresponding MAMs .

Effect of cultural background and healthcare environment on postoperative opioid requirement

PURPOSE

The objective of this prospective observational study was to investigate the interactions between cultural background, healthcare environment, and postoperative pain experience.

METHODS

We enrolled 128 Chinese patients living in rural mainland China and 134 patients in Hong Kong with a higher level of Western cultural influences (defined by educational attainment, place of residence, and ability to understand English). All patients had major abdominal surgery and received patient-controlled analgesia with intravenous morphine for postoperative pain relief. The primary endpoint was total opioid requirement up to 48 hr after surgery. Other measures included pain intensity, opioid-related side effects, and genetic markers for opioid responsiveness.

RESULTS

The mean (95% confidence interval) cumulative opioid requirement, expressed as morphine equivalent, during the first 48 hr after surgery was significantly less in patients from mainland China (18.8 [15.7 to 22] mg) compared with patients from Hong Kong (42.0 [38.3 to 45.6] mg, P < 0.0001). In a multivariable analysis, opioid requirement was influenced by ethnicity, duration of surgery, and severity of pain upon admission to the postanesthetic care unit.

CONCLUSIONS

These results suggest that postoperative pain behaviours and opioid requirement may be influenced by cultural background and healthcare environment in two populations of Chinese descent.

TRIAL REGISTRATION

Australian and New Zealand Clinical Trials Registry (ACTRN12614000601639); registered 6 May, 2014.

Association of ethnicity with the minimum alveolar concentration of sevoflurane

BACKGROUND

Selective breeding produces animal strains with varying anesthetic sensitivity. It thus seems unlikely that various human ethnicities have identical anesthetic requirements. Therefore, the authors tested the hypothesis that the minimum alveolar concentration of sevoflurane differs significantly as a function of ethnicity.

METHODS

The authors recruited 90 American Society of Anesthesiologists physical status I and II adult patients belonging to three Jewish ethnic groups: European, Oriental, and Caucasian (from the Caucasus Mountain region). All were scheduled to undergo surgery requiring a skin incision exceeding 3 cm. Without premedication, anesthesia was induced with 6-8% sevoflurane in 100% oxygen, and tracheal intubation was facilitated with succinylcholine. The skin incision was made after a predetermined end-tidal concentration of sevoflurane of 2.0% was maintained for at least 10 min in the first patient in each group. Blinded investigators observed the patient for movement during the subsequent minute. The concentration in the next patient was increased by 0.2% when patients moved, or decreased by the same amount when they did not. Results are presented as means [95% confidence intervals].

RESULTS

Morphometric and demographic characteristics were similar among the groups; however, mean arterial pressure was slightly greater in European Jews. Minimum alveolar concentration for sevoflurane was greatest in Caucasian Jews (2.32% [2.27-2.41%]), less in Oriental Jews (2.14% [2.06-2.22%]), and still less in European Jews (1.9% [1.82-1.99%]) (P < 0.001).

CONCLUSIONS

The results suggest that minimum alveolar concentration varies as a function of ethnicity. However, the extent to which confounding characteristics contribute, including lifestyle choices and environmental factors, remains unknown.

Opioid requirements and responses in Asians

The provision of good analgesia can be influenced by ethnic differences in how pain is expressed, the attitudes of patients and health professionals towards pain management and pharmacological differences in the responses to opioids. It is difficult to generalize results so that they are applicable to any ethnic group as a whole. There is also the question of how best to categorize ethnic Asians who have been in Australasia for several generations. Much of the pharmacogenetic work has focused on the metabolism of codeine, morphine and pethidine, and there are some differences between Chinese and Caucasians. Asians may receive less analgesia because they are more likely to experience, or are less tolerant of the adverse effects of opioids. Despite this, ethnic factors are probably only a small contributor to the inter-individual variation in opioid requirements. Unlike earlier studies, recent larger studies using patient-controlled analgesia have shown similar opioid usage between Asians and Caucasians in the postoperative period. An individualized pain management program is essential for any patient, whatever his or her ethnic origin. The use of patient-controlled analgesia will minimize some of the problems that may occur because of poor communication between the patient and the healthcare staff. Nevertheless, in a multicultural society like Australia's, health professionals should be conscious of the many factors that may influence the effects of prescribed treatment to manage pain in different ethnic groups.

Minimum alveolar concentration of halothane: an ethnic comparison

The minimum alveolar concentration (estimate of spread) of halothane which was determined in 42 Chinese, Nepalese or European patients was found to be 0.70% (0.66-0.74%) in Chinese and 0.70% (0.65-0.76%) in Nepalese and 0.68% (0.65-0.72%) in Europeans, using the Spearman Kärber method of analysis. This preliminary trial suggests that there is no ethnic difference in the minimum alveolar concentration of halothane between Asians and Europeans.

Suxamethonium myalgia: an ethnic comparison with and without pancuronium pretreatment

The incidence of myalgia after suxamethonium was determined in 200 fit military male dental patients of European, Chinese and Nepalese descent. Half received pancuronium 1 mg and the other half received saline pretreatment on a randomised double-blind basis. The percentage incidence of postsuxamethonium myalgia after saline or pancuronium was found to be: Europeans 26%, 13%; Chinese 13%, 7%; Nepalese 20%, 14%. Although pancuronium reduced the incidence of myalgia by about 50% overall, these values were not significantly different from each other. The recovery of spontaneous ventilation following suxamethonium was quicker in the Europeans than in the Asians (p < 0.05). Pancuronium pretreatment also delayed the recovery of spontaneous ventilation and recovery from neuromuscular block (p < 0.05) but this was independent of ethnicity. The Europeans recovered from anaesthesia more quickly than the Asians. It was concluded that ethnicity affected recovery from suxamethonium and from anaesthesia but was not of clinical relevance to the incidence of myalgia in male Asians and Europeans.

Inter-ethnic differences in postoperative pethidine requirements

A preliminary study of 24 hours' postoperative analgesia using a patient-controlled analgesia technique was undertaken in eight European and fourteen Asian adult patients. All patients had upper abdominal surgery and received weight-related doses of pethidine postoperatively via a Cardiff Palliator. Both groups had a similar degree of analgesia as assessed by visual analogue score but the Asian patients were more sedated in the postoperative period. The Asian patients made 24% fewer demands for analgesia and had a smaller mean (SD) pethidine consumption, 7.62 (2.04) mg.kg-1, compared with the European patients, 9.97 (2.14) mg.kg-1, (P less than 0.05) during the first 24 hours. Further research is necessary to determine whether the smaller requirement for analgesia in Asian patients is a result of pharmacokinetic or pharmacodynamic differences.

Tubeless anaesthesia for microlaryngeal surgery

An anaesthetic technique for laryngeal microsurgery is described and evaluated using intravenous propofol infusion and topical lignocaine with the patient breathing spontaneously without an endotracheal tube. Eighty adult patients divided into two groups according to their ASA status (Group A; 58 ASA I and II; Group B; 22 ASA III and IV) were analysed. Operating conditions were good in all but one case. Good anaesthesia was achieved in about 70% of patients. The requirement for propofol was less in Group B. Blood pressures decreased significantly following induction (P less than 0.001) but returned towards the preoperative values after ten minutes in Group A patients whereas the recovery was slower in Group B. Apnoea occurred on induction in about 40% of patients overall. PaCO2 showed a similar small increase in both groups. Oxygenation was adequate. The results show that propofol as an infusion in this simple tubeless technique is satisfactory. As the technique was considered potentially hazardous in those patients with upper airway obstruction, such patients were not included in this study.