COPD急性加重期呼吸衰竭伴意识障碍患者的无创通气研究?

目的:研究无创正压通气(NIPPV)治疗慢性阻塞性肺疾病急性加重期(AECOPD)呼吸衰竭伴意识障碍患者的疗效。方法:16例慢性阻塞性肺疾病急性加重期呼吸衰竭伴意识障碍行无创正压通气(NIPPV),并与同期14例慢性阻塞性肺疾病急性加重期呼吸衰竭无意识障碍患者比较。结果:慢性阻塞性肺疾病急性加重期呼吸衰竭伴意识障碍患者通气2～4小时后,pH由(7.16±0.08)升至(7.28±0.05),PCO_2由(111±20)降至(91±21),而且多数病人意识转清,两组治疗有效率分别为81%和86%(12/14),A组略低于B组,但两组差异无显著性(P>0.05)(12/16)。结论:意识障碍不应是无创正压通气(NIPPV)的禁忌症,加强意识障碍患者清醒前呼吸道分泌物吸引及胃胀气的引流,合理选用机械同气模式和参数是治疗成功的关键。     

Estimating the input function non-invasively for FDG-PET quantification with multiple linear regression analysis: simulation and verification with in vivo data

A novel statistical method, namely Regression-Estimated Input Function (REIF), is proposed in this study for the purpose of non-invasive estimation of the input function for fluorine-18 2-fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET) quantitative analysis. We collected 44 patients who had undergone a blood sampling procedure during their FDG-PET scans. First, we generated tissue time-activity curves of the grey matter and the whole brain with a segmentation technique for every subject. Summations of different intervals of these two curves were used as a feature vector, which also included the net injection dose. Multiple linear regression analysis was then applied to find the correlation between the input function and the feature vector. After a simulation study with in vivo data, the data of 29 patients were applied to calculate the regression coefficients, which were then used to estimate the input functions of the other 15 subjects. Comparing the estimated input functions with the corresponding real input functions, the averaged error percentages of the area under the curve and the cerebral metabolic rate of glucose (CMRGlc) were 12.13±8.85 and 16.60±9.61, respectively. Regression analysis of the CMRGlc values derived from the real and estimated input functions revealed a high correlation (r=0.91). No significant difference was found between the real CMRGlc and that derived from our regression-estimated input function (Students t test, P>0.05). The proposed REIF method demonstrated good abilities for input function and CMRGlc estimation, and represents a reliable replacement for the blood sampling procedures in FDG-PET quantification.     

Reliability of non-invasively acquired human genomic DNA as a substrate for real-time PCR-assisted analysis of genetic polymorphisms

Molecular epidemiological studies require high numbers of participants. The combination of an non-invasive access to human DNA with a rapid genotyping analysis, e.g. by use of LightCycler assisted real-time polymerase chain reaction (PCR), can be helpful in conducting such trials. The aim of our study was to define, for the first time, the use of LightCycler technology in analysis of non-invasively derived DNA. DNA extracted from blood, mouthwash and buccal cytobrush samples from 100 volunteers was analyzed for the genotypes of cytochrome P450 CYP1B1, and glutathione S-transferases GSTT1, GSTM1 and GSTP1. The median amounts of DNA isolated from blood, mouthwash and buccal cytobrush samples were 95, 11 and 8 µg, respectively. While genotyping for CYP1B1 codon 432 polymorphism and GSTP1 codon 105 polymorphism resulted in a complete correspondence for all three modes of sampling, the identification of individuals with null-genotype for GSTT1 or GSTM1 failed in some cases due to atypical courses of the corresponding melting curves, leading to high false-positive rates in the group of non-invasively derived samples. Thus, the results presented here call for caution in using LightCycler assisted real-time PCR in non-invasively collected samples, at least when appropriate control strategies are not implemented.T. Neuhaus and G. Geisen contributed equally to this work     

Effects of acupuncture on skin and muscle blood flow in healthy subjects

In 14 healthy female subjects, the effects of needle stimulation (acupuncture) on skin and muscle blood flow were investigated using a non-invasive custom-designed probe and photoplethysmography (PPG). In randomised order, 2–7 days apart, three modes of needle stimulation were performed on the anterior aspect of the tibia: superficial insertion (SF), insertion into the anterior tibial muscle (Mu), and insertion into the muscle including manipulation of the needle in order to elicit a distinct sensation of distension, heaviness or numbness (DeQi). Before intervention, the subjects rested for 30 min. After the intervention, the needle was left in situ for 20 min. Blood flow recordings were performed intermittently from 10 min prior to the intervention to the end of the trial. In a fourth session, serving as control, corresponding measurements were performed without any needle stimulation. Area under curve was calculated for 5-min periods prior to and after stimulation, respectively, and for the remaining 15-min period after stimulation. Compared to the control situation, muscle blood flow increased following both Mu and DeQi for 20 min, with the latter being more pronounced for the initial 5 min. Skin blood flow increased for 5 min following DeQi. However, no increase was found following SF. The DeQi stimulation was preceded by higher visual analogue scale ratings of anxiety prior to stimulation, which might have influenced skin blood flow to some extent. The results indicate that the intensity of the needling is of importance, the DeQi stimulation resulting in the most pronounced increase in both skin and muscle blood flow.     

Effects of simulated environmental conditions on glucocorticoid metabolite measurements in white-tailed deer feces

Environmental conditions may influence fecal glucocorticoid metabolite measurements if feces cannot be collected immediately after deposition. To evaluate the influence of environmental conditions on fecal glucocorticoid metabolite concentrations, we exposed fresh fecal samples to 1 of 5 simulated conditions: (1) room temperature (22 degrees C), (2) high heat (38 degrees C), (3) alternating high heat and room temperature cycle, (4) alternating freezing (-20 degrees C) and room temperature cycle, and (5) simulated rainfall (0.85 cm every other day at 22 degrees C) for 7 days. We collected fresh white-tailed deer (Odocoileus virginianus) feces at various times pre- and post-adrenocorticotropin injection to provide samples with initially low (n=5), medium (n=5), and high (n=5) glucocorticoid concentrations. Feces were mixed thoroughly and then allocated into five 10-g samples. Also, a 5-g sub-sample was taken from each fecal mass prior to treatment and stored at -20 degrees C until assayed. We subsampled from all treatments once every 24-h for 7 days. Fecal samples were assayed using [125I]corticosterone radioimmunoassay kits. Fecal glucocorticoid metabolites in all three groups in the simulated rainfall treatment and the low group in the alternating freezing and room temperature treatment increased significantly over the 7-day period. We believe increased microbial metabolism of fecal glucocorticoids may partly explain these results. Other biochemical processes (e.g., cleavage of conjugate side groups from hormone metabolites by non-microbial action or release of glucocorticoids from lipid micelles) may also have increased fecal glucocorticoid measurements. Our findings suggest that fecal samples exposed to rainfall for one week may artificially inflate fecal glucocorticoid measurements. Thus, researchers should recognize the potential bias when collecting fecal samples exposed to rainfall. Non-fresh samples may prove useful when care is taken to address the elevation in immunoreactive glucocorticoid concentrations.     

Validation of a tonometric noninvasive arterial blood pressure monitor in the intensive care setting

Intra-arterial measurement is considered the gold standard for continuous, beat-to-beat arterial blood pressure monitoring. However, arterial cannulation can be difficult and may cause complications such as thrombosis and ischaemia. Recently, a tonometric system, the Colin CBM-7000 has been developed for noninvasive beat-to-beat measurement of arterial blood pressure from the radial artery. We assessed the level of agreement between the CBM-7000 and invasive radial artery measurements in 15 patients on a neuro-intensive care unit. Agreement of systolic, diastolic and mean arterial pressure values was limited, with approximately 34% of mean arterial pressures differing by over 10 mmHg. In many cases, this was due to a downward drift of the noninvasive measurements over time. Furthermore, there was a tendency to underestimate low pressures and overestimate high pressures. In our opinion, the Colin CBM-7000 cannot be recommended for continuous blood pressure monitoring in the intensive care setting.     

Non-invasive intravascular monitoring in the pediatric hemodialysis population

Assessment of dry weight in pediatric hemodialysis (HD) patients is difficult, since small fluid shifts may result in dialysis-associated morbidity (DAM) and children may not verbalize complaints. Achieving dry weight is critical since chronic fluid overload can result in hypertension and left ventricular hypertrophy. To determine if non-invasive monitoring of hematocrit (NIVM) is useful in preventing DAM in pediatric HD patients, we reviewed 200 HD treatments performed with or without NIVM (no NIVM). DAM was defined as an ”event” (e.g., hypotension, headache, cramping) that required nursing intervention. Patient age, weight, and gender were similar in both groups. Desired ultrafiltration was obtained in both groups. The event rate was lower in NIVM than no NIVM for all treatments (0.22 vs. 0.3, P=0.07) and significantly lower in patients <35 kg (0.25 vs. 0.47, P=0.01). The second event rate (fraction of treatments with one event that had a subsequent event occurring at least 15 min later) was lower with NIVM (P<0.01). For the NIVM group, events in the first 90 min occurred when blood volume changed >8% per hour; 71% of events (43/60) at 90–240 min occurred when blood volume changed >4% per hour. NIVM decreases DAM in pediatric HD patients, especially those <35 kg. Ultrafiltration with blood volume change <8% per hour is safe in the 1st h and <4% after 1 h reduces DAM in children. Received: 5 June 2000 / Revised: 29 August 2000 / Accepted: 6 September 2000     

家庭氧疗加无创通气治疗慢性阻塞性肺疾病稳定期及其对运动耐量的影响

目的 观察家庭氧疗加无创通气对慢性阻塞性肺疾病(COPD)稳定期的治疗效果及对运动耐量的影响.方法 采用自身对照方法,将患者治疗前后及治疗期间的血气分析及6 min步行实验结果进行对比观察.结果 10例完成疗程的患者治疗前后血气分析及6 min步行实验结果差异均有统计学意义(均P＜0.05).结论 COPD稳定期实施家庭氧疗及无创通气治疗安全可行,效果较好.     

容积补偿法监测连续每搏无创血压的进展

无创血压是最常用的监护参数，本文介绍了连续每搏无创血压的新技术，容积补偿法的原理和应用。