Successful weaning from cardiopulmonary bypass after cardiac surgery using inhaled nitric oxide

Two cases of very difficult weaning from cardiopulmonary bypass after cardiac surgery in children with pulmonary hypertension and ventricular dysfunction are reported. Children fail to respond to conventional therapy combining nitrovasodilators and inotropic support and react successfully to combined inhaled nitric oxide (NO) and epinephrine or left atrial infused norepinephrine. Postoperative NO inhalation must be prolonged and no toxicity appears. Pulmonary endothelial function recovers only after several days.     

Hyperglycaemia compensates for the defects in insulin-mediated glucose metabolism and in the activation of glycogen synthase in the skeletal muscle of patients with Type 2 (non-insulin-dependent) diabetes mellitus

Summary Insulin resistance and a defective insulin activation of the enzyme glycogen synthase in skeletal muscle during euglycaemia may have important pathophysiological implications in Type 2 (non-insulin-dependent) diabetes mellitus. Hyperglycaemia may serve to compensate for these defects in Type 2 diabetes by increasing glucose disposal through a mass action effect. In the present study, rates of whole-body glucose oxidation and glucose storage were measured during fasting hyperglycaemia and isoglycaemic insulin infusion (40 mU·m^–2min^–1, 3 h) in 12 patients with Type 2 diabetes. Eleven control subjects were studied during euglycaemia. Biopsies were taken from the vastus lateralis muscle. Fasting and insulin-stimulated glucose oxidation, glucose storage and muscle glycogen synthase activation were all fully compensated (normalized) during hyperglycaemia in the diabetic patients. The insulin-stimulated increase in muscle glycogen content was the same in the diabetic patients and in the control subjects. Besides hyperglycaemia, the diabetic patients had elevated muscle free glucose and glucose 6-phosphate concentrations. A positive correlation was demonstrated between intracellular free glucose concentration and muscle glycogen synthase fractional velocity insulin activation (0.1 mmol/l glucose 6-phosphate: r=0.65, p<0.02 and 0.0 mmol/l glucose 6-phosphate: r= 0.91, p<0.0001). In conclusion, this study indicates an important role for hyperglycaemia and elevated muscle free glucose and glucose 6-phosphate concentrations in compensating (normalizing) intracellular glucose metabolism and skeletal muscle glycogen synthase activation in Type 2 diabetes.     

Should nitrous oxide be discontinued before desflurane after anaesthesia with desflurane/N2O?

Background : The appearance of hypoxaemia immediately after anaesthesia with nitrous oxide may be partially explained by diffusion hypoxia. This study was undertaken to evaluate circulatory and respiratory variables during emergence after desflurane/nitrous oxide anaesthesia, and whether there are any differences depending on which gas is discontinued first. Methods : 20 patients were studied after gynaecological laparoscopic surgery. The depth of anaesthesia was reduced 10 min prior to the emergence by stopping the administration of one of the two inhalational agents. Desflurane was discontinued first in Group 1, nitrous oxide in Group 2. Ventilation was controlled with E'C0₂ maintained at 5% until the administration of the second anaesthetic gas was discontinued. Thereafter, the patients breathed spontaneously. Results : The PaC0₂ at which the respiratory drive reappeared after controlled normoventilation was similar in both groups, 6.1–6.5 kPa, and extubation was performed after 10–11 min. At extubarion, the end–tidal C0₂ and total MAC were similar in the groups, about 6.2 vol% and 0.16, respectively. Mean arterial blood pressure was significantly higher in Group 1. The cardiac output increased in both groups from about 6 1/min at the conclusion of anaesthesia to 9.0 and 7.6 1/min at 15 min in the recovery period. End–tidal O₂ decreased and CO₂ increased in both groups during the first 10 min in the recovery period. pH was reduced at 15 and 30 min in both groups. Conclusion : Irrespective of which agent was discontinued first, there was an increase in cardiac output, decrease in oxygenation and a modest acidosis in the first 30–min recovery period. The only significant difference between the groups was in mean arterial blood pressure in the early emergence phase with a greater MAP when N₂O had been used until the conclusion of anaesthesia.     

一氧化氮在氯胺酮麻醉机制中的作用

目的：了解一氧化氮（ＮＯ）与氯胺酮麻醉作用间的关系。方法：６０只雄性昆明鼠分成４组，Ⅰ组氯胺酮１００ｍｇ／ｋｇ腹腔内注射，Ⅱ组连续３天腹腔内注射Ｎ－硝基左旋精氨酸甲酯（Ｌ－ＮＡＭＥ）５０ｍｇ／ｋｇ后，腹腔内注射氯胺酮１００ｍｇ／ｋｇ，Ⅲ组连续３天腹腔内注射左旋精氨酸３００ｍｇ／ｋｇ后，腹腔内注射氯胺酮１００ｍｇ／ｋｇ，Ⅳ组腹腔内注射氯胺酮１００ｍｇ／ｋｇ后，腹腔１小时内持续给予Ｓ－亚硝酰－Ｎ－乙酰青霉胺（ＳＮＡＰ）３０ｍｇ／ｋｇ。观察各组动物翻正反射丧失和抑制持续时间。结果：各组翻正反射丧失时间无明显差异，为１．３９～２．３０分钟。翻正反射丧失持续时间Ⅰ组４７．７１±５．１７分，Ⅱ组４７．８４±７．９９分，Ⅲ组和Ⅳ组明显比Ⅰ、Ⅱ组短，分别为３１．１４±２．４４和３２．７５±８．１４分（Ｐ＜０．０１）。结论：改变ＮＯ的生成量将影响着氯胺酮引起的小鼠翻正反射抑制的持续时间，ＮＯ在氯胺酮麻醉分子机制中起作用。     

先天性心脏病患儿肺动脉,上腔静脉血一氧化氮含量检测及意义

目的:探讨一氧化氮(NO)与先天性心脏病(CHD)引起的肺动脉高压(PH)发病间的关系。方法:应用NO试剂盒检测了CHD患儿肺动脉及上腔静脉血浆中NO含量。结果;(1)伴PH组肺动脉血浆NO含量明显高于不伴肺动脉高压组(37.58±9.99μmol/L:19.03±15.25μmol/L,P<0.01);(2)在PH组中,肺动脉血浆NO含量明显高于上腔静脉血(P<0.01);而不伴PH组,肺动脉和上腔静脉血浆NO含量无显著性差异(P>0.05)。结论:(1)伴PH的先心患儿肺动脉血浆NO含量升高;(2)NO可能介入了CHD引起的PH发病过程。     

吸入一氧化氮对心瓣膜置换术后肺动脉高压患者血流动力学的影响

目的：观察吸入一氧化氮（ＮＯ）对心瓣膜置换术后肺动脉高压患者血流动力学的影响。方法：选择９例心瓣膜置换术后伴肺动脉高压的病人，吸入ＮＯ０．００３％，观察三个时象点：吸入ＮＯ前；开始吸入ＮＯ后１５分钟；停止吸入ＮＯ后１５分钟。结果：吸入ＮＯ能显著降低肺动脉压和肺循环阻力指数（Ｐ＜０．０１），停止吸入ＮＯ１５分钟后，肺动脉压和肺循环阻力指数恢复到原有水平。在整个观察过程中，心率、平均动脉压、中心静脉压、肺动脉楔压、体循环阻力指数和心脏指数均无显著变化（Ｐ＞０．０５）。结论：吸入ＮＯ具有选择性肺血管扩张作用，是治疗心瓣膜置换术后肺动脉高压的较理想药物。     

Association analysis of CA repeat polymorphism of the endothelial nitric oxide synthase gene with essential hypertension in Japanese

The nitric oxide synthase (NOS) gene is thought to be associated with essential hypertension (EH), because NO is implicated in endothelium-mediated vasodilation. We investigated the possible association between the alleles of simple tandem repeat DNA polymorphism of the endothelial constitutive NOS (cNOS) gene and EH in Japanese subjects. In all, 100 patients with EH and 123 subjects with normal blood pressure were studied. Polymerase chain reaction was used to amplify the CA repeat site in the endothelial cNOS gene and alleles based on the CA repeat number were determined. The allele frequencies in the hypertensive group and normotensive group were then compared. Twenty-three alleles were identified in this study of Japanese subjects. The overall distributions of allele frequencies in the two groups were not significantly different. However, comparing the allele frequencies in the EH group without left ventricular hypertrophy (LVH) and the normotensive group, the overall distributions were significantly different (p = 0.019). The 33-repeat allele was found more frequently in the EH group without LVH than in the normotensive group (p = 0.000047, Odds ratio = 3.71). In conclusion, the 33-repeat allele of the endothelial cNOS gene is associated with EH without LVH, and may be a genetic marker of EH in Japanese subjects.     

硬膜外注入异氟醚－氧化亚氮气体增强利多卡因麻醉作用

我们对５０例子宫、卵巢手术病人，使用利多卡因做硬膜外麻醉，其中２５例向硬膜外腔内注入异氟醚－氧化亚氮气体。２组对比发现，实验组麻醉平面明显高于对照组，在同样手术时间内实验组所使用的利多卡因量明显少于对照组。表明异氟醚－氧化亚氮气体有增强利多卡因的硬膜外麻醉作用，同时未发现注入吸入麻醉药产生副作用。     

ZMW型环氧乙烷灭菌箱对骨移植材料灭菌效果的初步观察

目的 :观察ZMW型环氧乙烷灭菌箱对异体骨材料灭菌效果 ,旨在寻找一种安全、经济的灭菌方法。方法 :清洁条件下取骨 ,制成 0 .5cm× 0 .5cm× 2cm湿润骨材料和干燥骨材料 ,抽取样本 ,用ZMW型环氧乙烷灭菌箱 (15 0L)在不同温度及时间下消毒 ,以环氧乙烷指示胶带是否变色作为灭菌指标 ,样本在消毒前后分别作细菌培养。结果 :不同消毒条件下 ,每批样本均有细菌生长 ,干燥骨材料有菌率高于湿润的骨材料。结论 :ZMW型环氧乙烷灭菌箱不能使异体骨移植材料完全达到灭菌的要求 ,环氧乙烷指示胶带不能作为骨移植材料的灭菌指标 ,干燥可能使细菌的抗环氧乙烷能力增加 ,从而间接的影响了环氧乙烷的消毒效果。     

Increased carbon monoxide levels in the nasal airways of subjects with a history of seasonal allergic rhinitis and in patients with upper respiratory tract infection

BACKGROUND: Carbon monoxide (CO) has emerged as an endogenously produced gaseous mediator known to be involved in bronchial smooth muscle regulation. Increased amounts of CO have been found in exhaled air during asthma and lower airway inflammation. Recently CO has been shown to be produced in the nasal airways, but there are no reports of altered CO levels in nasal airways during inflammation. OBJECTIVE: This study was designed to investigate if CO levels increase in the human nasal airways during inflammatory conditions, such as allergy and upper airway respiratory tract infection (URTI). METHODS: CO was sampled separately from the upper and lower airways of 13 healthy control subjects, six patients with a history of allergic rhinitis and six patients with URTI. RESULTS: Nasal CO levels were increased in subjects with allergic rhinitis, compared to healthy controls (2.07 +/- 0.15 ppm, n = 6 and 1.62 +/- 0.08 ppm, n = 13, respectively, P < 0.01). CO levels were also increased in patients with URTI, compared to the same controls (1.92 +/- 0.09 ppm, n = 6, P < 0.05). Normal levels of CO were found in air from the lower airways among subjects with allergic rhinitis, whereas corresponding levels in the URTI patients were increased. CONCLUSION: The present data demonstrates that upper airway CO levels increase in parallel with different inflammatory stimuli, such as allergy and infection, suggesting a role for CO as marker or mediator of nasal inflammation.