[Sedation with stimulative circadian rhythm in mechanically ventilation patients in intensive care unit].

OBJECTIVE: To sedate the mechanically ventilation patients in intensive care unit (ICU) with stimulative circadian rhythm, and evaluate whether the protocol has advantages in recovering natural circadian rhythm, duration of mechanical ventilation, and length of ICU stay after weaning of sedation. METHODS: A prospective random control trial was conducted. One hundred and twenty ventilated patients in ICU were randomly assigned to four groups: circadian rhythm (CR), daily interruption (DI), continuous sedation (CS) or demand sedation (DS) group, each n = 30. Given more complications, DS group was deleted after recruiting 10 cases and 90 patients were admitted ultimately. Patients' age, gender, body weight, acute physiology and chronic health evaluation II (APACHE II) scores, sedatives dosages, daily arousal time, duration of mechanical ventilation, length of ICU stay, complications (ventilator-associated pneumonia, barotrauma with intrathoracic drain tube) and untoward reactions (accidental extubation, reintubation, tracheotomy, death) were recorded, the biochemical indicators were determined, as well as number of nurses on duty at 10:00 and 22:00. RESULTS: The patients' sex ratio, age, body weight, APACHEII scores, duration of mechanical ventilation, length of ICU stay showed no difference among CR, DI and CS groups. The total sedatives dosages (mg: 5466.7 ± 620.4) and average sedatives dosages [mg×h(-1) ×kg(-1): 2.19 ± 0.61] in CS group were significantly higher than those in CR group (4344.5 ± 816.0, 1.00 ± 0.51) and DI group (4154.3 ± 649.4, 1.23 ± 0.62, all P < 0.01), and there was no difference between CR group and DI group. Daily arousal time in the CR group (hours: 4.40 ± 1.30) was significantly lengthened compared with that in DI group (0.59 ± 0.26) and CS group (0.15 ± 0.02, both P < 0.05). The complications showed no differences in each group, but incidences of the untoward reactions in DI group (2 cases) were significantly increased compared with that in CR group (1 case) and CS group (0 case, P = 0.0477). After weaning of sedation, patients with normal circadian rhythm were significantly more in CR group than that in CS group (19 vs. 9, P = 0.0339). Among CR group, DI group and CS group, there were significant differences in the numbers of nurses on duty in the daytime (1.65, 1.41, 1.14, all P < 0.01), but there was no difference in the night. The biochemistry index showed no difference in each group. CONCLUSIONS: It demonstrated that sedation with stimulative circadian rhythm be helpful to create circadian rhythm after weaning of sedation. While complications and untoward reactions did not increase, as well as duration of mechanical ventilation and length of ICU stay. Therefore, the clinical applicability of this sedative strategy was highlighted.

[Measurement of methane and carbon dioxide emissions from ruminants based on the NDIR technique].

Methane (CH4) production in the rumen represents a loss of energy for the host animal; in addition, methane eructated by ruminants may contribute to a greenhouse effect or global warming. The dinumal CH4 and carbon dioxide (CO2) emissions from sheep were continuously recorded using the flow-through chamber method. A type new type of non-disperse infrared (NDIR) gas sensors based on pulse IR source was introduced, and by using the high performance pyroelectric IR sensor with built in interference filter and the "single light and two wavelengths" technology, CH4 and CO2 measurement from ruminants was achieved. Animals were given dry oat hay as the basic diet and supplemented concentrate with the ratio of 7 : 3. The results showed that the recovery was 96.7% and 96.2% for CH4 and CO2, respectively. Methane and carbon dioxide output from sheep respectively averaged 15.6 g per day and 184.7 g per day, equivalent to 6.8 and 71.1 kg per animal. Diurnal fluctuations in hourly rates of CH4 and CO2 production in hourly of methane increased during day light to reach a peak at or near sunset and then declined towards sunrise, and consideration was given to the dry matter intake of the animals used in these studies and its possible effects on CH4 production.

[Determination of inorganic elements in the soil-grass-animal system by sealed microwave digestion ICP-AES].

The contents of inorganic elements including K, Ca, Na, Mg, P, S, Fe, Cu, Mn, Zn, Mo, and Co in the soil-grass-animal mineral system from Qinghai Tibetan Plateau were determined by ICP-AES using high pressure system-sealed microwave digestion. The sample of soil was digested with HNO3-HF-H2O2 acids system, but others including pasture, animal fur, liver, and serum were digested with HNO3-H2O2 acids system. The operation would be simplified and the blank value would be decreased with the above acids systems. The results were proved to be reliable with the relative standard deviation being 0.271%-2.633% for Ca, 2.971%-4.854% for Co, 0.372%-2.874% for Cu, 0.600%-3.683% for Fe, 0.347%-2.829% for K, 0.626%-2.593% for Mg, 0.705%-4.828% for Mn, 2.946%-4.622% for Mo, 0.689%-3.621% for Na, 0.422%-3.890% for P, and 0.143%-4.622% for S, 0.166%-2.399% for Zn, and all of them were less than 5% for all the elements, and the recovery being 97.1%-101.4% for Ca, 93.5%-112.5% for Co, 95.2%-104.0% for Cu, 96.9%-104.2% for Fe, 96.1%-105.6% for K, 96.2%-102.8% for Mg, 91.5%-108.9% for Mn, 95.0%-113.5% for Mo, 95.2%-101.8% for Na, 94.7%-100.7% for P, 98.3%-108.4% for S, and 97.5%-102.0% for Zn by adding standard recovery experiment. The results of determination were proved that the method of sealed microwave digestion ICP-AES was sensitive, precise, easy to operate and rapid for the determination of inorganic elements in the soil-grass-animal mineral system, and could satisfy the sample examination request. The methods and results were meaningful to research on the soil-pasture-animal mineral system including the contents of mineral elements, the circulation of mineral elements, the interaction, and the application of mineral additive.

[Progress in application of near infrared reflectance spectroscopy to the study of ruminant nutrition].

The near infrared reflectance spectroscopy (NIRS) technique has been widely used in the study of ruminant nutrition with many of its operational merits such as facility, shortcut and accuracy, etc. Study suggested that the standard error of cross-validation (SECV) ranges from 1.6% to 2.8% in predicting organic matter digestion of ruminant diet by using the NIRS technique; the chemical and biological compositions and the microbial protein proportion in the duodenal digesta can be predicted accurately using the NIRS. However, the kinetic parameters of degradation are not well predicted; The prediction of intake of stall feeding animals by using NIRS is similar to the determination of in vivo method, but the standard error of prediction is about 14% when using the NIRS to predict intake of grazing animals. All of the studies suggest that big progress has been made in using NIRS technique to predict feed digestion and evaluate the diet quality and intake of ruminant animals, which also suggest that the NIRS technique has a wide prospect in the study of ruminant nutrition.

[Spectroscopy technique and ruminant methane emissions accurate inspecting].

The increase in atmospheric CH4 concentration, on the one hand through the radiation process, will directly cause climate change, and on the other hand, cause a lot of changes in atmospheric chemical processes, indirectly causing climate change. The rapid growth of atmospheric methane has gained attention of governments and scientists. All countries in the world now deal with global climate change as an important task of reducing emissions of greenhouse gases, but the need for monitoring the concentration of methane gas, in particular precision monitoring, can be scientifically formulated to provide a scientific basis for emission reduction measures. So far, CH4 gas emissions of different animal production systems have received extensive research. The methane emission by ruminant reported in the literature is only estimation. This is due to the various factors that affect the methane production in ruminant, there are various variables associated with the techniques for measuring methane production, the techniques currently developed to measure methane are unable to accurately determine the dynamics of methane emission by ruminant, and therefore there is an urgent need to develop an accurate method for this purpose. Currently, spectroscopy technique has been used and is relatively a more accurate and reliable method. Various spectroscopy techniques such as modified infrared spectroscopy methane measuring system, laser and near-infrared sensory system are able to achieve the objective of determining the dynamic methane emission by both domestic and grazing ruminant. Therefore spectroscopy technique is an important methane measuring technique, and contributes to proposing reduction methods of methane.

[A review on studies and applications of near infrared spectroscopy technique(NIRS) in detecting quality of hay].

The quality of hay can directly affect the price of hay and also livestock productivity. Many kinds of methods have been developed for detecting the quality of hay and the method of near infrared spectroscopy (NIRS) has been widely used with consideration of its fast, effective and nondestructive characteristics during detecting process. In the present paper, the feasibility and effectiveness of application of NIRS to detecting hay quality were expounded. Meanwhile, the advance in the study of using NIRS to detect chemical compositions, extent of incursion by epiphyte, amount of toxicant excreted by endogenetic epiphyte and some minim components that can not be detected by using chemical methods were also introduced detailedly. Based on the review of the progresses in using NIRS to detect the quality of hay, it can be concluded that using NIRS to detect hay quality can avoid the disadvantages of time wasting, complication and high cost when using traditional chemical method. And for better utilization of NIRS in practice, some more studies still need to be implemented to further perfect and improve the utilization of NIRS for detecting forage quality, and more accurate modes and systematic analysis software need to be established in times to come.

[Clinical trial to verify the value of the CD14(+) monocyte human leukocyte antigen DR as a marker in evaluating immunosuppression in patients with severe sepsis].

OBJECTIVE: To verify that CD14(+) monocyte human leukocyte antigen DR (HLA-DR) may serve as a reliable index for immunosupression, and for prediction of prognosis as well as to evaluate the efficacy of Thymopentin (TP-5) to enhance immunologic function in patients with severe sepsis, and to evaluate the validity of compensatory anti-inflammatory response syndrome (CARS). METHODS: Patients in a SICU with symptoms and signs of severe sepsis conforming to the criteria set forth by ACCP/SCCM were enrolled in this clinical trial. CD14(+) monocyte HLA-DR was determined by flow cytometry. To those with HLA-DR<30%, TP-5, 1 mg, q.d. was administered till HLA-DR raised or death occurred. Before the treatment was begun and ended, CD14(+) monocyte HLA-DR(+) and cytokines[tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), IL-10, IL-13] were respectively measured. RESULTS: Totally, 20 patients were enrolled in this study. Among them 15 survived and 5 died. After treatment with TP-5, CD14(+) monocyte HLA-DR was elevated in almost all the patients, including the nonsurvivors. However, only a statistically significant difference between the initial values and the final values was noted in the survivors. The levels of TNF-alpha and IL-6 dropped significantly concomitantly with the elevation of the CD14(+) monocyte HLA-DR in survivors. On the contrary, in the patients who died there was a tendency of an elevation of levels of these cytokines. No significant difference was found between the initial and final levels of both IL-10 and IL-13 with the treatment. CONCLUSION: 1. It was reconfirmed that the CD14(+) monocyte HLA-DR could be a reliable and valuable index to judge immunosupression in septic patients and determine the effectiveness of immunostimulative therapy. 2. It was reconfirmed that the level of CD14(+) monocyte HLA-DR can serve as an index to predict the outcome of septic patients. 3. TP-5, as a new immunostimulative agent used in sepsis, might be effective to revert immunosupression. However, a further clinical trial with a larger number of patients and a better control should be done to finally verify it. 4. It is found that immunosupression do not seem to be related with the balance between pro- and anti-inflammatory cytokines, suggesting that the hypothesis of CARS should be further appraised.