失血性休克复苏及监测指标研究进展

创伤、失血性休克是一古老的临床研究课题。不仅在平时常见，更重要的是与战伤救治密切相关。尽管近10年来取得了一些进展，但复苏时机、复苏目标、液体种类的选择、复苏后继续生命支持以及监测技术等仍是临床以及研究人员面临的重大挑战。本文将就近年来有关上述问题的最新研究进展进行分析和讨论，以期提高对该复杂综合征的认识，为今后的研究提供帮助。     

Maintenance of body temperature in elderly patients who have joint replacement surgery A comparison between the heat and moisture exchanger and heated humidifier

The effect of a heat and moisture exchanger on intra-operative aural canal (core) and mean skin temperatures was investigated in elderly patients who had elective total hip arthroplasty under general anaesthesia with artificial ventilation of the lungs. Group 1 (n = 20) did not receive any form of artificial humidification while in group 2 (n = 20) a heat and moisture exchanger was inserted in the breathing system and in group 3 (n = 20) the inspired gases were humidified and warmed at 40 degrees C by means of a heated humidifier. Time of surgery, intravenous fluid administration and operating theatre temperature were standardised. Mean (SD) aural canal (core) temperature decreased significantly in groups 1 and 2 (p less than 0.001), while there was a fall of 0.3 degrees C (0.6) in group 3, which was not significant. Mean skin temperature decreased during anaesthesia and surgery in both groups 1 and 2 (p less than 0.05), while it increased in group 3. There was a significantly greater loss of body heat in groups 1 and 2 compared with group 3 intra-operatively (p less than 0.001). We conclude tha a heat and moisture exchanger did not prevent the decrease in intra-operative body temperature in elderly patients.     

EFFECT OF CIGARETTE SMOKING ON THE FREQUENCY OF VENTRICULAR PREMATURE COMPLEXES IN NORMAL SUBJECTS

1. Ambulatory ECG monitoring was undertaken in healthy cigarette smokers (33) and non-smokers (20) of similar age (21-66 years). 2. The frequency of ventricular premature complexes (VPC) was less in habitual smokers (P less than 0.05; Mann-Whitney rank test) and an average of more than 1 VPC per hour occurred in a higher proportion of non-smokers than smokers: eight of 20 (40%) vs two of 33 (6%) (P less than 0.01; Chi-square test).     

Diffuse Axonal Injury (DAI) is not Associated with Elevated Intracranial Pressure (ICP)

Summary Objective. Traditionally, intracranial pressure (ICP) monitoring has been utilized in all patients with severe head injury (Glasgow coma score of 3–8). Ventriculostomy placement, however, does carry a 4 to 10 percent complication rate consisting mostly of hematoma and infection. The authors propose that a subgroup of patients presenting with severe head trauma and diffuse axonal injury without associated mass lesion, do not need ICP monitoring. Additionally, the monitoring data from ICP, MAP, and CPP for a comparison severe head injury group, and subgroups of DAI would be presented. Materials and methods. Thirty-six patients sustaining blunt head trauma and fitting our strict clinical and radiographic diagnosis of DAI were enrolled in our study. Inclusion criteria were severe head injury patients who did not regain consciousness after the initial impact, and whose CT scan demonstrated characteristic punctate hemorrhages of <10 mm diameter at the greywhite junction, basal ganglia, corpus callosum, upper brainstem, or a combination of the above. Patients with significant mass lesions and documented anoxia were excluded. Their intracranial pressure (ICP) and cerebral perfusion pressure (CPP) were compared to a control group of 36 consecutive patients with severe non-penetrating non-operative head injury, using the Analysis for Variance method. Results. Eighteen (50.0%), six (16.7%), and twelve (33.3%) patients had types I, II, and III DAI, respectively. The admission Glasgow Coma Score (GCS) was higher for types I and II than for type III DAI. ICP was monitored from 23 to 165 hours, with a mean ICP for 36 patients of 11.70 mmHg (SEM=75) and a range from 4.3 to 17.3 mmHg. Of all ICP recordings, of which 89.7% (2421/2698) were ≤20 mmHg. Average mean arterial pressure (MAP) was 96.08 mmHg (SEM=1.69), and 94.6% (2038/2154) of all MAP readings were greater than 80 mmHg. Average cerebral perfusion pressure (CPP) was 85.16 mmHg (SEM=1.68), and 90.1% (1941/2154) of all CPP readings were greater than 70 mmHg. This is compared to the control group mean ICP, MAP, and CPP of 16.84 mmHg (p=0.000021), 92.80 mmHg (p=0.18), and 76.49 mmHg (p=0.0012). No treatment for sustained elevated ICP>20 mmHg was needed for DAI patients except in two; one with extensive intraventricular and subarachnoid hemorrhage who developed communicating hydrocephalus, and another with ventriculitis requiring intrathecal and intravenous antibiotic treatments. Two complications, one from a catheter tract hematoma, and another with Staph epidermidis ventriculitis, were encountered. All patients, except type III DAI, generally demonstrated marked clinical improvement with time. The outcome, as measured by Glasgow Coma Score (GCS) and Glasgow Outcome Score (GOS) was similarly better with types I and II than type III DAI. Conclusion. The authors conclude that ICP elevation in DAI patients without associated mass lesions is not as prevalent as other severe head injured patients, therefore ICP monitoring may not be as critical. The presence of an ICP monitoring device may contribute to increased morbidity. Of key importance, however, is an accurate clinical history and interpretation of the CT scan.     

Reversal of profound paralysis: use of large doses of edrophonium to antagonize vecuronium and pancuronium induced neuromuscular blockade

The ability to evoke reversal of dense vecuronium- and pancuronium-induced paralysis (T1 10% of control) with edrophonium 1.0 mg.kg-1 was studied using train-of-four nerve stimulation and electromyographic monitoring. Two different end-points, train-of-four ratios of 0.5 and 0.7, were used to define "adequate reversal", and the results for both relaxants were compared. Reversal was reliable and rapid for vecuronium if either ratio was used with times of 2.8 (1.5) and 9 (3) min required to achieve ratios of 0.5 and 0.7, respectively. However, if the block was due to pancuronium, reversal was unreliable with 2 of 9 and 4 of 9 patients not achieving ratios of 0.5 and 0.7, respectively. Reversal was also markedly prolonged in this group with a mean time of 37 (23) min to achieve a ratio of 0.7, and in almost half these patients a supplementary dose of edrophonium was required.     

A simple and inexpensive metabolic cage for mice

An inexpensive and easily constructed metabolic cage for mice is presented. This apparatus can reliably monitor food and fluid consumption, as well as urine and fecal output, in a relatively non-intrusive manner.     

Noninvasive,automatic 24-h ambulatory blood pressure monitoring in normotensive subjects

Summary The reliability of noninvasive, automatic blood pressure monitoring is not yet clearly established. A 24-h ambulatory blood pressure profile was obtained in 9 healthy, normotensive subjects with an automatic, noninvasive device. The blood pressure profile showed the typical circadian pattern with lower systolic and diastolic values during sleep, although pulse pressure was fairly constant (about 40 mm Hg). The systolic blood pressure rose steeply in the early morning hours — before waking up. The results were compared with simultaneous hourly readings using the auscultatory method. There were no statistically significant differences between the automatic and auscultatory readings, 13 of the 18 mean values at. different time points being within 2 mm Hg of each other. All the auscultatory means fell within the 95% confidence limits of those measured hourly by the automatic method. Although the automatic method seemed to be reliable compared with the auscultatory method, its sensitivity to motion artifacts is a disadvantage in a truly ambulatory setting.     

Spectral signature and heterodyne efficiency for different wavelengths in laser Doppler flowmetry

Laser Doppler perfusion monitoring and imaging technologies generate time traces and two-dimensional flow maps of the microcirculation. With the goal of reaching different tissue depths, these technologies are equipped with lassers operating at different wavelengths λ. The fact that the average scattering angle, at a single scattering event, between a photon and a red blood cell increases with λ is compensated for by a 1/λ effect in the scattering vector, rendering the average frequency shift virtually independent of the choice of wavelength. Monte Carlo simulations showed that the corresponding spectral signature of the Doppler signals for λ=632.8nm and 780nm were close to identical. The theoretical predictions were verified by calculating the centre-of-gravity (COG) frequency of the laser Doppler power spectral density for the two wavelengths from forearm and finger skin, representing a low and high perfusion area, respectively (forearm COG=123 against 121Hz, finger COG=220 against 212 Hz). When the wavelength changes from 632.8nm to 780nm, the heterodyne efficiency of the detector and, thereby, the inherent system amplifcation increase. For tissues with identical microvascular flow conditions, the output signal therfore tends to increase in magnitude when shifting to longer wavelengths.     

EEG enhancement during electrosurgery using an optical fibre

The paper considers the limiting factors in EEG enhancement in the presence of electrosurgery interference and presents a design for a useful fibre-optic EEG monitoring instrument which is free from such problems as electrical shock (micro and macroshock), patient burns and susceptibility to electrosurgery interference associated with conventional EEG monitors.