Convection warmers — not just hot air

We sought to determine whether the forced air convection warmers (nine Bair Huggers, Augustine Medical, and one Warm Touch, Mallinkrodt Medical) used in our operating theatres could be a source of microbial pathogens. Agar plates were placed directly in the air stream of the warmers. Four of these grew potentially pathogenic organisms. When the warmers were set to blow through perforated blankets, no growth occurred. Three of the warmers were swabbed and sites of colonisation were found in their hoses. After fixing a microbial filter to the end of the hose, organisms were no longer detectable. We conclude that these warming devices are a potential source of nosocomial infection. They should only be used in conjunction with perforated blankets, should have their microbial filters changed regularly and their hoses sterilised. The inclusion of a microbial filter into the nozzle of the hose could be incorporated into the design of the warmer.     

The effect of cooling on toe systolic pressures in subjects with and without Raynaud's syndrome in the lower extremities

Summary. The effect of changes in local and body temperature on the toe systolic pressures was studied in 20 subjects with and 30 without Raynaud's syndrome in the toes. The pressures were significantly lower in the group with Raynaud's syndrome under all experimental conditions (P < 0·01). The pressures were significantly lower during body cooling than during body warming in both groups (P < 0·01). The mean decrease with body cooling was 58 mmHg in the group with Raynaud's syndrome and 24 mmHg in the control subjects (P < 0·01). During body cooling pressures fell to less than 30 mmHg in 70% of subjects with Raynaud's syndrome and in 3% of the controls. Local cooling from 30 to 10°C during body cooling resulted in a significant mean decrease in pressure of over 40 mmHg in both groups (P < 0·01) and the pressure fell below 30 mmHg in over 90% of the group with and in 26% of those without Raynaud's attacks. The results indicate the importance of body cooling and local temperature in the mechanism of vasospasm in the toes. They are also relevant to the diagnosis of Raynaud's syndrome in the lower limbs and have implications for the testing of patients with arteriosclerotic occlusion since erroneously low pressure values could be obtained in tests when the feet are cold.     

膀胱冲洗液适宜温度的临床探讨

目的 :确定最适温度的膀胱冲洗液 ,最大限度的减少膀胱痉挛的次数和强度 ,减少出血 ,提高病人生活质量。方法 :采用六组不同温度冲洗液对术后病人行持续膀胱冲洗 ,记录膀胱痉挛次数 ,膀胱出血程度及体温变化的情况。结果 :随着冲洗液温度升高 ,膀胱痉挛平均次数减少 ,冲洗前后患者体温差逐渐变小 ,2 0℃～ 3 0℃温度组术后冲洗液红细胞计数平均数明显低于其它温度组。结论 :2 0℃～ 3 0℃是持续膀胱冲洗的最适温度     

Persistent loss of thermoregulation in the rat induced by 3,4-methylenedioxymethamphetamine (MDMA or “Ecstasy”) but not by fenfluramine

Using radio-biotelemetry, the timecourse of recovery and sensitivity to ambient temperature (Ta) of the thermogenic response of methylenedioxymethamphetamine (MDMA or “Ecstasy”) was examined. Ambient temperatures of 17 and 22°C produced very different response profiles, with the lower temperature producing a hypothermic response to 10 and 15 mg/kg doses of MDMA, and the higher temperature producing a profound hyperthermia to the same doses. Although the peak responses to the drug had subsided within 5 h of administration, residual effects, in the form of an elevation of body temperature during the “low” phase of the diurnal cycle, were present for a further 48 h. Long-lasting disruption of the thermoregulatory system following a short series of MDMA administrations (10 mg/kg once per day for 4 days) was shown by exposing the rats in the undrugged state to a thermoregulatory challenge, consisting of 60-min exposure to a Ta of 30°C, at 1 week before, and at 4 weeks and 14 weeks after the drug administration. MDMA-treated rats showed a prolonged hyperthermic response to the challenge at both post-drug intervals compared with fenfluramine-treated rats and saline-treated controls. Thus, the results indicate both that MDMA’s thermogenic effects are more sensitive to Ta than previously demonstrated, and that the serotonergic neurotoxicity of the drug may produce long-lasting changes in thermoregulatory mechanisms. Received: 7 December 1997/Final version: 23 January 1998     

Delayed sleep phase syndrome: A placebo-controlled cross-over study on the effects of melatonin administered five hours before the individual dim light melatonin onset

In a double-blind placebo-controlled cross-over study, 30 patients with Delayed Sleep Phase Syndrome (DSPS) were included, of whom 25 finished the study. Melatonin 5 mg was administered during two weeks in a double-blind setting and two weeks in an open setting successively or interrupted by two weeks of placebo. The study's impact was assessed by measurements of the 24-h curves of endogenous melatonin production and rectal temperature (n=14), polysomnography (n=22), actigraphy (n=13), sleep log (n=22), and subjective sleep quality (n=25). Mean dim light melatonin onset (DLMO) (±SD), before treatment, occurred at 23.17 hours (±138 min). Melatonin was administered five hours before the individual DLMO. After treatment, the onset of the nocturnal melatonin profile was significantly advanced by approximately 1.5 hour. Body temperature trough did not advance significantly. During melatonin use, actigraphy showed a significant advance of sleep onset and polysomnography, a significant decreased sleep latency. Sleep architecture was not influenced. During melatonin treatment patients felt significantly more refreshed in the morning. These results show that analysis of DLMO of patients suffering from DSPS is important both for diagnosis and therapy. These results are discussed in terms of the biochemistry of the pineal.     

Limitations of a thermal camera in measuring surface temperature of laser-irradiated tissues

Thermal cameras are used in research laboratories to measure tissue temperature during laser irradiation. This study was an evaluation of the accuracy of a 3-5 microns thermal camera and two 8-12 microns cameras in detecting the maximum temperatures of small targets. The size of the targets was within the range of laser spot diameters which are used for vessel welding, angioplasty, and dermatology. The response to a sharp thermal edge was measured and analyzed for the three cameras, which had a scanning rate of 30 frames per second. The response of the 3-5 microns camera to reference black body targets of different sizes was also studied. It was found that the detector system required an average of 2.44 microseconds to reach 90% of maximum step response for the 8-12 microns system and 5.85 microseconds for the 3-5 microns system. With a 3 x telescope and a 9.5 inch focal distance close-up lens, the 3-5 microns camera underestimated the temperature of targets smaller than 2.0 mm because of its slow detector response. Although the 8-12 microns camera provides more accurate measurements due to its faster detector response, it still underestimates the temperature of targets smaller than 900 microns, when similar magnification and focal distance are used. Methods to compensate for the inaccuracies are discussed, including empirical correction factors and the inverse filtering technique.     

美托洛尔对急性心肌梗死早期QT离散度的影响

目的 :探讨急性心肌梗死早期应用美托洛尔对QT离散度 (QTd)的影响。方法 :选择符合条件的 14 2例急性心肌梗死 (AMI)患者 ,男 95例 ,女 47例 ,平均年龄 5 7± 12 3岁 ,随机分为治疗组 78例 ,对照组 64例 ,两组病例性别、年龄等基本情况相似。在AMI常规治疗的基础上 ,治疗组给予美托洛尔 6 2 5～ 5 0mg口服 ,2次 /d ;对照组仅常规治疗。治疗前及治疗 1周后同步记录体表常规 12导联心电图 ,每一导联连续测量 3个Q -T间期 ,取其均值。最大QT间期 (QTmax)与最小QT间期 (QTmin)之差为QTd。结果 :治疗组在常规治疗基础上早期给予美托洛尔后 ,QTd、QTcd显著缩小 (P <0 0 1) ,QTmax无明显改变 (P >0 0 5 ) ,QTmin显著延长 (P <0 0 5 ) ,心率显著减慢 (P <0 0 1)。而对照组QTd、QTcd、QTmax、QTmin、HR均无明显变化 (P >0 0 5 )。结论 :AMI早期应用 β1 受体阻滞剂美托洛尔治疗 ,可显著延长正常心肌的复极过程 ,从而防治早期恶性心律失常 ,降低猝死率。     

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目的通过建立完全性睡眠剥夺的幼鼠模型,探讨短期完全性睡眠剥夺对幼鼠体温调节及生长的影响。方法2005-01-03将上海交通大学附属新华医院儿科研究所12只出生后3周刚断奶的雄性幼鼠,随机分为试验组和对照组。采用小站台水环境的方法对幼鼠进行48h的睡眠剥夺。睡眠剥夺前、24h及48h后,分别进行体温、体重及进食量的监测,并计算日能耗,睡眠剥夺结束后处死幼鼠并对重要脏器进行称量。结果实验结果表明48h睡眠剥夺后,两组幼鼠体温均出现随时间变化特点,在睡眠剥夺24h后增高,48h后出现体温下降;睡眠剥夺后试验组幼鼠体重明显低于对照组,而试验组的进食量在48h后明显多于对照组;在日能量消耗的比较中,试验组在24h睡眠剥夺后的能耗明显高于对照组;睡眠剥夺48h后各器官重量仅双肺重量与体重的比值在两组间存在差异。结论幼鼠完全性睡眠剥夺的早期即出现体温显著下降,较早显现体温调节中枢的失衡,并且体格发育受到显著影响。     

婴儿培养箱基本性能研究与改进

根据对婴儿培养箱多年的临床使用与维修体会,阐述了婴儿培养箱基本性能要求,并指出现行的此类设备存在的问题,及具体改进方法。     

Intracerebral temperature monitoring in severely head injured patients

Summary In a series of 6 severely head injured patients, intraventricular as well as rectal, bladder and jugular vein temperature is recorded. The relationship between these temperatures in different conditions is evaluated. Intracerebral temperature is 0.5±0.2 °C (mean ± SD) higher than bladder temperature except in conditions such as brain death. It is concluded that rectal temperature is not representative and therefore not a good alternative to the measurement of brain temperature. More data on human intracerebral temperature are mandatory as well as prospective studies correlating intracerebral temperature with final outcome in head injury.