不同剂量布托啡诺治疗硬膜外麻醉后寒战临床观察

目的 观察不同剂量布托啡诺治疗硬膜外麻醉后寒战的临床效果。方法 将45例出现硬膜外麻醉后寒战病人随机分为Ⅰ、Ⅱ、Ⅲ共3组，每组15例，分别静脉注射布托啡诺0．01、0．02、0．03mg／kg，观察用药后寒战治疗效果、镇静程度、不良反应。结果 Ⅰ、Ⅱ、Ⅲ组有效率分别为60．0％、93．3％和93．3％，11组、Ⅲ组疗效显著好于Ⅰ组（uc=2．623、2．888，P〈0．01）；Ⅰ组、Ⅱ组用药后5min OAA／S评分显著高于Ⅲ组，差异均有显著意义（t=3．695、2．550，P〈0．05）；Ⅲ组不良反应发生率显著高于Ⅰ、Ⅱ组（P=0．0003）。结论 0．02mg／kg布托啡诺静脉注射适用于治疗硬膜外麻醉后寒战。     

Intra-operative fluid warming in elective caesarean section: a blinded randomised controlled trial

BackgroundWe assessed the effect of warming intravenous fluids during elective caesarean section under combined spinal-epidural anaesthesia in a blinded, randomised controlled trial.MethodSeventy-five women having elective caesarean section were randomly assigned to receive all intravenous fluids at room temperature, or heated in a cabinet set at 45°C or via a Hotline^® fluid warmer (Smiths Medical International Ltd, Watford, Herts, UK). After 10 mL/kg crystalloid preload, combined spinal-epidural anaesthesia was performed. Core and ambient temperatures, thermal comfort and shivering were measured every 15 min thereafter. The primary outcome was the temperature at 60 min.ResultsTemperature decreased in all groups. Although the temperature decrease at 60 min was similar in the heated cabinet and Hotline® groups, the room temperature group exhibited a greater decrease [difference 0.4°C (95% CI 0.2-0.6°C); P = 0.015]. More women felt cold in the room temperature group (8: 32%) than in the heated cabinet set (3: 12%) and Hotline® (1: 4%) groups (P = 0.02), but the incidence of shivering was similar: 11 (44%), 9 (36%) and 7 (28%) respectively. Apgar scores and neonatal cord gases were similar.ConclusionWarming intravenous fluids mitigates the decrease in maternal temperature during elective caesarean section under combined spinal-epidural anaesthesia and improves thermal comfort, but does not affect shivering. Intravenous fluids should be warmed routinely in elective caesarean section, especially for cases of expected long duration, but the use of pre-warmed fluids is as efficient and cheaper than using a Hotline^® fluid warmer.     

Studies on the ascending pathways from the thermosensitive region of the spinal cord

Summary In young guinea pigs the ascending pathways from the spinal thermosensitive region were studied by means of 1. microelectrode recording and 2. micro-electrocoagulation. In the first series of studies, impulse frequency was recorded from single units of the spinothalamic tract which responded to a temperature rise in the spinal segments C₅-T₂ with an increase of discharge frequency. At a spinal cord temperature of 38–39° C these units showed a firing rate of 1–5 imp./sec; local heating of the spinal cord (dT/dt=0.1° C/sec) to 40–41° C caused an increase in discharge frequency to 20–25 imp./sec. The mean static impulse frequency was 3 imp./sec at a spinal cord temperature of 39° C, and 10 imp./sec at a spinal cord temperature of 42.5° C.In the second series of studies bilateral RF-coagulations were carried out in different sites of the diencephalon. These experiments showed that the ascending fibres from the spinal thermosensitive region connect the thermosensitive spinal region with a hypothalamic temperature control centre.Supported by the Deutsche Forschungsgemeinschaft (Br. 184/10).     

曲马朵预防急性阑尾炎手术患者围术期寒战的效果观察

目的观察曲马朵预防急性阑尾炎患者围术期寒战和预先镇痛的效果。方法选择在连续硬膜外麻醉下行阑尾切除的患者100例,随机分为4组,每组25例。麻醉起效后,A、B、c组分别静脉注射曲马朵1、1．5、2mg／kg;D组给予生理盐水2ml。术毕前,A、B、C3组均静脉滴注曲马朵2mg／kg、格拉司琼3mg,加生理盐水500ml。D组静脉滴注生理盐水500ml。观察围术期患者呼吸循环的变化、术后镇痛效果,记录寒战、恶心呕吐的发生率等。结果4组患者呼吸循环变化差异无统计学意义（P〉O．05）;A、B、C组寒战发生率及程度显著低于D组;A、B、C三组术后镇痛情况良好,首次疼痛触发时间明显延长,与其他组相比,B组患者满意度最高。结论曲马朵1．5mg／kg术中静脉推注可有效预防阑尾切除术围术期寒战反应,术毕前静脉滴注2mg／kg,具有良好的术后镇痛作用。     

Reflex changes in discharge activities of gamma efferents to varying skin temperatures in cats

Summary Changes in spontaneous discharges of single -efferents dissected from the lumbrosacral ventral root of spinal cats were observed during cooling of warming of a small area of the foot pad skin of the ipsilateral hind limb. In a certain range of skin temperature, varying from 34°C to 38°C from preparation to preparation, temperature changes resulted in either an increase or decrease in discharge frequency, whereas above this temperature range, heating produced an increase in discharge frequency. By contrast, all -efferents examined responded with a negative temperature coefficient to a change in skin temperature below the respective temperature. The thermal activation of these efferents elicited by a small temperature change of the skin was affected considerably by the velocity rather than by the degree of temperature changes but the effect of both variables differed according to the skin temperature at which the temperature change occurred. Ratios of increment or decrement in discharge frequency (± imp./s) to degree (± °C) and velocity of temperature change (± °C/s) respectively were plotted as a function of skin temperature, and indicated a directional relationship between stimulus and response by attaching to each ratio either a positive or negative temperature coefficient. The maximum activity response in the range of 20–30°C was –19 imp./s per °C at 22°C and the average was –8.33±4.77 imp./s per °C. In the warmer range, the coefficients were positive and the average was 23.79±12.21 imp./s per °C in the range of 40–44°C. The steady state activity at a constant temperature showed no sign of dependency on skin temperature. On the basis of these results, the possible mechanisms for thermal inflow contributing to a thermally-induced reflex of the -motoneurons and the functional implications of these reflexes for the thermoregulatory system are discussed.     

不同温度局麻药物对硬膜外麻醉后寒战的影响作用

目的探讨不同温度的局麻药对硬膜外麻醉后寒战的影响。方法选择120例拟在硬膜外麻醉下行子宫或附件手术的妇科患者,随机分为4组(每组30例):T35组、T30组、T25组和T20组。硬膜外分别注入温度为35、30、25和20℃的局麻药。观察并分析麻醉后寒战的发生率、寒战的严重程度、寒战的发生时间及术中体温的变化等情况。结果T35组和T30组的寒战发生率约为10%,T25组为30%,T20组为40%,T25组、T30组与T25组和T20组比较差异均有显著意义(P<0.05或0.01)。结论硬膜外麻醉时用温度大于30℃的局麻药,可有效地降低寒战的发生率。     

The degree of chills for risk of bacteremia in acute febrile illness

Purpose

Patients with acute febrile illness may experience different degrees of chills. To evaluate the different degrees of chills in predicting risk of bacteremia in patients with acute febrile illness, we performed a single-center prospective observational study.

Methods

We enrolled consecutive adult patients with acute febrile illness presenting to our emergency department. We defined mild chills as cold-feeling equivalent such as the need of an outer jacket; moderate chills as the need for a thick blanket; and shaking chills as whole-body shaking even under a thick blanket. We estimated risk ratios of the different degrees of chills for bacteremia using multivariable adjusted Poisson regression.

Results

Of a total 526 patients, 40 patients (7.6%) had bacteremia. There were 65 patients (12.4%) with shaking chills, 100 (19%) with moderate chills, and 105 (20%) with mild chills. By comparing patients with no chills, the risk ratios of bacteremia were 12.1 (95% confidence interval [CI] 4.1-36.2) for shaking chills, 4.1 (95% CI 1.6-10.7) for moderate chills, and 1.8 (95% CI 0.9-3.3) for mild chills. Shaking chills showed a specificity of 90.3% (95% CI 89.2-91.5) and positive likelihood ratio of 4.65 (95% CI 2.95-6.86). The absence of chills showed a sensitivity of 87.5% (95% CI 74.4-94.5) and negative likelihood ratio of 0.24 (95% CI 0.11-0.51).

Conclusion

Evaluation of the degree of chills is important for estimating risk of bacteremia in patients with acute febrile illness. The more severe degree of chills suggests the higher risk of bacteremia.     

Temperatures of skin,subcutaneous tissue,muscle and core in resting men in cold,comfortable and hot conditions

Summary To examine the core-shell model of temperature distribution and the possible role of subcutaneous temperature in heat regulation, comprehensive temperature measurements were made on six nude resting men exposed for 2–3 h to comfort (27° C), cold (15° C) and heat (45° C). Cold produced strong shivering and heat caused heavy sweating. Temperatures were recorded every 10 min from: esophagus, rectum and auditory canal; back muscle and thigh muscle at 20 mm and 40 mm depths; 6 subcutaneous sites; and 16 skin sites. Average temperatures at these 29 sites were tabulated at the ends of comfort, hot and cold and at the onsets of sweating and shivering. Body temperature changes were slow to develop, the skin temperatures being fastest, and successively deeper tissues progressively slower. There was occasional after-drop and after-rise. The data were consistent with the core-shell concept. The temperature gradient from subcutaneous tissue to skin, which differed substantially with comfort, the onset of shivering and the onset of sweating, could serve as a regulatory signal. The data are now in computer format and may be of interest to biothermal modelers.     

Comparison of the action of prostaglandin with endotoxin on thermoregulatory response thresholds

Prostaglandin E₂ (PGE₂) and lipopolysaccharide (LPS) derived fromE. coli were injected into the lateral cerebral ventricle of rabbits at 30° C ambient temperature. The threshold core temperatures for ear cutaneous vasoconstriction. (Th _v) and shivering (Th _sh) were determined by whole-body cooling with an intestinal thermode. Each threshold, as determined at the plateau phase of LPS fever and PGE₂ hyperthermia respectively, were compared with the control values before LPS and PGE₂ injection.Th_sh was not changed by the injection of LPS, whileTh _v was increased. After PGE₂ injection bothTh _sh andTh _v were increased in comparison to their control levels. These changes paralleled the elevation of core temperature.The present study does not exclude prostaglandins as humoral mediators involved in some of the central processes generating fever, but suggest at the same time that there are additional properties of LPS fever for which prostaglandins do not account.     

Low-dose intravenous dexmedetomidine reduces shivering following cesarean delivery: a randomized controlled trial

BackgroundIntravenous dexmedetomidine 30 µg reduces shivering after cesarean delivery but can result in sedation and dry mouth. We hypothesized that prophylactic administration of 10 µg of IV dexmedetomidine would reduce the patient-reported severity of shivering after cesarean delivery, without an increased incidence of side effects.MethodsAfter institutional review board approval and informed written consent, women undergoing scheduled cesarean delivery with spinal or combined spinal-epidural anesthesia were randomized to receive either intravenous normal saline or dexmedetomidine 10 µg immediately after delivery. The primary outcome was a patient-rated subjective shivering score using a 10-cm visual analog scale at 30 and 60 min after arrival in the Post-Anesthesia Care Unit. Secondary outcomes included subjective scores for pain, nausea, itching, dry mouth, and sedation, as well as 24-h medication administration and investigator-rated observations of shivering, vomiting, pruritus, and sedation. Repeated measures ANOVA with Tukey-Kramer multiple-comparison test was applied for primary outcomes.ResultsOne hundred patients were enrolled, and 85 completed the study and were included in analysis. The mean ± SD shivering score in the dexmedetomidine group was significantly lower by repeated measures analysis than among controls across the first 60 min (P=0.0002), and individually at both 30 and 60 min (placebo 1.8 ± 2.6 vs. dexmedetomidine 0.6 ± 1.4 at 30 min; 1.2 ± 2.1 vs. 0.3 ± 0.6 at 60 min; both P <0.01). Patient-rated and observer-rated side effects did not significantly differ between groups.ConclusionsProphylactic administration of intravenous dexmedetomidine 10 µg after delivery reduces shivering without notable side effects.