The aim of this study was to find out whether a correlation exists between changes in brain tissue oxygen pressure (ti-p02) and hemoglobin oxygenation (Hb02) measured by near-infrared spectroscopy. We studied 10 patients with severe head injury. A ti-p02 monitoring device was introduced in the frontal white matter as soon as possible after administration. Additionally a NIRS sensor Was placed at the forehead. All data were recorded simultaneously. 'Changes of the ti-p02 curve were defined as events with the following criteria: > 10% change from the baseline value, > 3 min duration, clearly not an artifact. 137 events were found with a mean change of ti-p02 of 8.3 ± 10.2 mmHg. In 77.4% we observed a corresponding change of the Hb02. In 7 patients we found a good correlation (r> 0.7) between change ti-p02 and change Hb02. In 3 patients the correlation was poor. The reason for poor correlation might be poor signal quality of the NIRS sensor or inhomogenous distribution of ischemic areas in the whole brain. We conclude that under the condition of a stable NIRS signal and a diffuse brain lesion, changes of ti-p02 are well reflected by NIRS. [Neural Res 1997; 19: 246-248]
To investigate the accuracy of jugular bulb venous monitoring in detecting cerebral ischemia, we performed ipsilateral jugular bulb venous monitoring in 48 patients undergoing carotid surgery under regional anesthesia. Cerebral ischemia was assumed when neurologic deterioration occurred. During carotid clamping, the maximal arterial-jugular venous oxygen content difference [AJDO2 (max)], the minimal jugular venous oxygen saturation [SjO2 (min)], the maximal arterial-jugular venous lactate content difference [AJDL (max)], the maximal lactate oxygen index [LOI (max)], and the maximal modified LOI [mLOI (max)] were determined. To quantify the selectivity of each parameter, we performed receiver operating characteristic analysis and determined the area under the curve. The cutoff points providing the highest accuracy and the corresponding sensitivity (Se) and specificity (Spec) were determined. Neurologic deterioration occurred in 12 patients. All parameters, except AJDO2 (max), showed significant ability to distinguish between ischemic and nonischemic patients. The area under the curve for AJDL (max) was 0.840, for SjO2 (min) 0.766, for LOI 0.745, for mLOI 0.748, and for AJDO2 (max) 0.672. We found cutoff points of ≥0.16 mmol/L for AJDL (max) (Se=67%; Spec=86%) and ≤55% for SjO2 (Se=75%; Spec=83%). In conclusion, the present investigation shows that AJDL, SjO2, LOI, and mLOI provide the ability to detect cerebral hypoperfusion. The highest accuracy was found for AJDL. Neither the calculation of LOI nor of mLOI showed improved results.
Abstract Background Significant long-term reduction in health-related quality of life (HRQoL) is often observed in survivors of the acute respiratory distress syndrome (ARDS), and return to work (RtW) is limited. There is a paucity of data regarding the relationship between the quality of care (QoC) in the intensive care unit (ICU) and both HRQoL and RtW in ARDS survivors. Therefore, the aim of our study was to investigate associations between indicators of QoC and HRQoL and RtW in a cohort of survivors of ARDS. Methods To determine the influence of QoC on HRQoL and RtW 1 year after ICU-discharge, ARDS patients were recruited into a prospective multi-centre patient cohort study and followed up regularly after discharge. Patients were asked to complete self-report questionnaires on HRQoL (Short Form 12 physical component scale (PCS) and mental component scale (MCS)) and RtW. Indicators of QoC pertaining to volume, structural and process quality, and general characteristics were recorded on ICU level. Associations between QoC indicators and HrQoL and RtW were investigated by multivariable linear and Cox regression modelling, respectively. B values and hazard ratios (HRs) are reported with corresponding 95% confidence intervals (CIs). Results 877 (of initially 1225 enrolled) people with ARDS formed the DACAPO survivor cohort, 396 were finally followed up to 1 year after discharge. The twelve-month survivors were characterized by a reduced HRQoL with a greater impairment in the physical component (Md 41.2 IQR [34–52]) compared to the mental component (Md 47.3 IQR [33–57]). Overall, 50% of the patients returned to work. The proportion of ventilated ICU patients showed significant negative associations with both 12 months PCS (B = − 11.22, CI −20.71; − 1,74) and RtW (HR = 0,18, CI 0,04;0,80). All other QoC indicators were not significantly related to outcome. Conclusions Associations between ICU QoC and long-term HrQoL and RtW were weak and largely non-significant. Residual confounding by case mix, treatment variables before or during ICU stay and variables pertaining to the post intensive care period (e.g. rehabilitation) cannot be ruled out. Trial registration Clinicaltrials.govNCT02637011 . (December 22, 2015, retrospectively registered)
This study compares the accuracy of cerebral monitoring systems in detecting cerebral ischemia during carotid endarterectomy.The authors compared transcranial Doppler sonography (TCD), near-infrared spectroscopy (NIRS), stump pressure (SP) measurement, and somatosensory evoked potentials (SEP) in 48 patients undergoing carotid surgery during regional anesthesia. Cerebral ischemia was assumed when neurologic deterioration occurred. During clamping, the minimum mean middle cerebral artery velocity (TCD(min)), its percentage change (TCD%), the minimum regional saturation of oxygen (NIRS(min)), its percentage change (NIRS%), the mean SP, and the changes of SEP amplitude were recorded. To analyze the corresponding sensitivity and specificity of each parameter, the authors performed receiver operating characteristic analysis.Neurologic deterioration occurred in 12 patients. SP and NIRS were successfully performed in all patients. TCD monitoring was not possible in 10 (21%); SEP was not possible in 2 patients (4%). All parameters provided the ability to distinguish between ischemic and nonischemic patients. TCD% and NIRS% showed significantly better discrimination than TCD(min) and NIRS(min) (P < 0.05). The highest area under the curve (AUC) was found for TCD% (AUC = 0.973), but there was no significant difference compared with NIRS% (AUC = 0.905) and SP (AUC = 0.925). The lowest AUC was found for SEP (AUC = 0.749), which was significantly lower than that for TCD%, NIRS%, and SP.TCD%, NIRS%, and SP measurement provide similar accuracy for the detection of cerebral ischemia during carotid surgery. Lower accuracy was found for SEP monitoring. Because of the high rate of technical difficulties (21%), TCD monitoring was the least practical of the investigated monitoring devices.
We investigated the effects of aerosolized prostacyclin (PGI2) administration on hemodynamics and pulmonary gas exchange in 8 patients with severe respiratory failure and acute pulmonary hypertension. Nebulization of epoprostenol (5 ng/kg body weight for 15 min) decreased mean pulmonary blood pressure from 41.2 +/- 6.7 mm Hg (mean +/- SD, before administration) to 36.1 +/- 6 mm Hg < or = 15 min (p < 0.05). The effect was reversed 10 min after discontinuation of PGI2 (40.9 +/- 6.3 mm Hg). Pulmonary vascular resistance index (339 +/- 138 dynes.s.cm-5.m2, before administration) was significantly (p < 0.05) reduced < or = 15 min (260 +/- 89 dynes.s.cm-5.m2) and increased again after discontinuation of PGI2 (341 +/- 142 dynes.s.cm-5.m2). The ratio of arterial oxygen to the fraction of inspired oxygen (PaO2/FiO2) increased from 119 +/- 34 mm Hg (before administration) to 163 +/- 76 mm Hg (15 min after initiation of administration p < 0.05) and was reduced after PGI2 discontinuation (116 +/- 35 mm Hg). Heart rate, mean blood pressure, central venous pressure, and pulmonary arterial wedge pressure remained unchanged, whereas cardiac index was slightly reduced. We assume that PGI2 aerosolization is a beneficial technique, applied with a ventilator nebulization system. The beneficial effect might be caused by selective pulmonary vasodilatation in well-ventilated areas of the lung.
Background S-100, a protein of astroglial cells, is described as a marker for central nervous system damage. The aim of this study was to evaluate whether the marker could give information about the severity and possibility of functional recovery after minor and severe head injury. Methods Thirty patients after severe head injury (Glasgow Coma Scale score <9) and 11 patients after minor head injury (Glasgow Coma Scale score > 12) were included. In each case, blood samples were drawn within 6 hours after injury. Outcome was estimated at hospital discharge using the Glasgow Outcome Scale. Results All patients who sustained minor head injury had reached a favorable outcome by the time they were discharged from the hospital. Their mean S-100 serum level was 0.35 [micro sign]g/L. Patients who sustained severe head injury and were classified as having an unfavorable outcome (31%) showed a mean serum concentration of 4.9 [micro sign]g/L, whereas patients classified as having a favorable outcome (69%) had a mean S-100 level of 1.2 [micro sign]g/L. All groups differed significantly (p < 0.05) Conclusion S-100 appears to be a promising marker for the severity of head injury and neuronal damage.
Perhaps, the most interesting part of Cloud Computing is rapid elasticity. To be able to exploit the elasticity of a cloud infrastructure, the applications usually need to be able to scale horizontally, i.e. it must be possible to add (and also remove) nodes offering the same capabilities as the existing ones. In such scenarios, a load balancer is usually used. To keep the manual labor down, the load balancer should automatically be able to distribute load to the newly added nodes. In this paper, we show how to transform the popular Apache Web Server (which is only able to act as a static load balancer) into a dynamic cloud-ready load balancer.
