Postoperative Drainage for 6, 12, or 24 Hours After Burr-Hole Evacuation of Chronic Subdural Hematoma in Symptomatic Patients (DRAIN-TIME 2): Study Protocol for a Nationwide Randomized Controlled Trial

Background: Chronic subdural hematoma (CSDH) is a common acute or subacute neurosurgical condition, typically treated by burr-hole evacuation and drainage. Recurrent CSDH occurs in 5-20 % of cases and requires reoperation in symptomatic patients, sometimes repeatedly. Postoperative subdural drainage of maximal 48 hours is effective in reducing recurrent hematomas. However, the shortest possible drainage time without increasing the recurrence rate is unknown.Methods: DRAIN-TIME 2 is a Danish multi-center, randomized controlled trial of postoperative drainage time including all four neurosurgical departments in Denmark. Both incapacitated and mentally competent patients are enrolled. Patients older than 18 years, free of other intracranial pathologies or history of previous brain surgery, are recruited at time of admission or no later than 6 hours after surgery. Each patient is randomized to either 6, 12, or 24 hours of passive subdural drainage following single burr-hole evacuation of a CSDH. Mentally competent patients are asked to complete the SF-36 questionnaire. The primary endpoint is CSDH recurrence rate at 90 days. Secondary outcome measures include SF-36 at 90 days, length of hospital stay, drain-related complications, and complications related to immobilization and mortality.Discussion: This multi-center trial will provide evidence regarding shortest possible drainage time without increasing the recurrence rate. The potential impact of this study is significant as we believe that a shorter drainage period may be associated with fewer drain-related complications, faster mobilization, fewer complications related to immobilization, and shorter hospital stays—thus reducing the overall health service burden from this condition. The expected benefits for patients’ lives and health costs will increase as the CSDH patient population grows.Trial registration: ISRCTN15186366. https://doi.org/10.1186/ISRCTN15186366. Registered in December 2020 and updated in October 2021.This protocol was developed in accordance with the SPIRIT checklist and by use of the structured study protocol template provided by BMC Trials.

National randomized clinical trial on subdural drainage time after chronic subdural hematoma evacuation

OBJECTIVE Placement of a subdural drain reduces recurrence and death after evacuation of chronic subdural hematoma (CSDH), but little is known about optimal drainage duration. In the present national trial, the authors investigated the effect of drainage duration on recurrence and death. METHODS In a randomized controlled trial involving all neurosurgical departments in Denmark, patients treated with single burr hole evacuation of CSDH were randomly assigned to 24 hours or 48 hours of postoperative passive subdural drainage. Follow-up duration was 90 days, and the primary study outcome was recurrent hematoma requiring reoperation. Secondary outcome was death. In addition, complications and length of hospital stay were recorded and analyzed. RESULTS Of the 420 included patients, 212 were assigned 24-hour drainage and 208 were assigned 48-hour drainage. The recurrence rate was 14% in the 24-hour group and 13% in the 48-hour group. Four patients died in the 24-hour group, and 8 patients died in the 48-hour group; this difference was not statistically significant. The ORs (95% CIs) for recurrence and mortality (48 hours vs 24 hours) were 0.94 (0.53–1.66) and 2.07 (0.64–7.85), respectively, in the intention-to-treat analysis. The ORs (95% CIs) for recurrence and mortality per 1-hour increase in drainage time were 1.0005 (0.9770–1.0244) and 1.0046 (0.9564–1.0554), respectively, in the as-treated sensitivity analysis that used the observed drainage times instead of the preassigned treatment groups. The rates of surgical and drain-related complications, postoperative infections, and thromboembolic events were not different between groups. The mean ± SD postoperative length of hospital stay was 7.4 ± 4.3 days for patients who received 24-hour drainage versus 8.4 ± 4.9 days for those who received 48-hour drainage (p = 0.14). The mean ± SD postoperative length of stay in the neurosurgical department was significantly shorter for the 24-hour group (2 ± 0.9 days vs 2.8 ± 1.6 days, p < 0.001). CONCLUSIONS No significant differences in the rates of recurrent hematoma or death during 90-day follow-up were identified between the two groups that randomly received either 24- or 48-hour passive subdural drainage after burr hole evacuation of CSDH.

Effect of Three Types of Drying on the Viability of Lactic Acid Bacteria in Foam-Mat Dried Yogurt

In this research, foaming technology was applied to obtain powdered yogurt from commercial yogurt at lower temperatures than the typical temperatures used during the dehydration process; the viability of lactic acid bacteria (LAB) was evaluated after the application of different drying techniques (conventional drying, freeze drying, and vacuum drying). Three different formulas (F1, F2, and F3) based on a foaming agent (albumen), stabilizers (guar gum), and prebiotics sources (inulin and agave syrup) were developed. Foam stability was evaluated at different pH values through optimum time of foam (OTF), medium drainage time (MDT), and drainage volume (DV). Foam expansion (FE) and foam density (FD) were measured. The OTF ranged from 6 to 10 min. The MDT ranged from 4.3 to 27.3 min, depending on pH, while the DV varied from 14.1 to 16.2 mL only in F1. No drainage was evidenced in F2 and F3, showing the best stability. The F2 and F3 produced the best FE and FD values. The dried yogurt with different techniques showed a survival rate (SR) of up to 85% Log-CFU/mL, even with the conventional drying method. Sensorial trials were carried out in reconstituted product, with the freeze-dried yogurt showing higher scores. The foam formulas developed demonstrate the efficacy of both the dehydration of yogurt and the preservation of LAB.

Influence of Long Boreholes Layout and Drilling Length on Gas Drainage Based on Multifield Coupling Model of Gas-Bearing Coal

Gas drainage through long seam boreholes is an effective method to prevent gas disasters in coal mines. In this paper, a multifield coupling model of gas migration in gas-bearing coal was first established. Then, a quantitative characterization method of gas drainage effect was put forward. Finally, the extraction effect of long boreholes was obtained under different layouts and drilling lengths. The research results show that, under the arrangement of long boreholes along the seam, the gas pressure around the borehole decreases significantly with the extraction time. There is no extraction blank in the middle of the working face. However, it is easy to cause uneven gas drainage in the combined arrangement of the long boreholes along the seam and the penetrating boreholes. Furthermore, it is found that the drainage volume of the long boreholes along the seam is similar to that of the joint layout under the same drainage time. As the length of the borehole increases, the influencing range of gas drainage increases. When the borehole lengths are 150 m and 240 m, the drainage volumes are about 1.31 and 2.50 times that of the 90 m boreholes, respectively. The research achievements could provide a specific reference for the layout of long boreholes along the bedding and the determination of reasonable parameters for gas drainage on site.

Suyyas’s Flood: Numerical Models of Kashmir’s Medieval Megaflood and Ancient Lake Kerewa Drainage Events

In the mid-ninth century, an earthquake triggered a landslide that blocked the narrow gorge of the Jhelum River where it exits the Kashmir Valley. The landslide impounded a lake that extended ≈100 km along the floor of the valley, implying an impounded volume of ≤21 km3, flooding the capital, Srinagar, and much agricultural land. An engineered breach of the landslide was contrived by a Medieval engineer resulting in the catastrophic release of flood waters. Using reasonable assumptions we calculate the probable minimum drainage time of this Medieval flood (&lt;4 days) and maximum downstream surge velocities (≈12 m/s). These would have been sufficient to transport boulders in the bed of the Jhelum with dimensions of ≈6 m, consistent with those currently present in some reaches of the river. Given the morphology of the Jhelum gorge we consider that landslide outburst floods may have been common in Kashmir’s history. Ancient shorelines indicate that paleo-lake volumes in the Kashmir Valley may have exceeded 400 km3 which, were they released in catastrophic floods, would have been associated with potential downstream outburst velocities &gt;32 m/s, able to transport boulders with dimensions ≈40 m, far in excess of any found in the course of the Jhelum or in the Punjab plains. Their absence suggests that Kashmir’s ancient lakes were not lowered by outburst mechanisms much exceeding those associated with Suyya’s flood. Present-day floods have been many tens of meters shallower than those impounded by landslides in the Jhelum in the past several thousands of years. A challenge for future study will be to date Kashmir’s ancient shorelines to learn how often landslides and major impoundment events may have occurred in the valley.

A Case Study on the Gas Drainage Optimization Based on the Effective Borehole Spacing in Sima Coal Mine

Based on the dynamic expressions of permeability and porosity of the coal seam derived in the paper, a multiphysical field coupling numerical model of gas migration under the interaction of stress field and seepage field was established. The gas drainage project #3 Coal Seam operated by Sima Coal Industry Co., Ltd., was selected as the study object. Taking different drainage time periods in various positions of drainage holes into consideration, combined with the advance situation of the 1207 working face in the Sima Coal Mine, a mixed layout gas drainage scheme featured with the effective borehole spacing was obtained through the COMSOL multiphysics simulation. In addition, a series of field industrial tests were performed to validate the research result, revealing that comprehensively considering the extraction time of coal and optimizing the layout of extraction boreholes can effectively improve the engineering economic benefits.

Numerical Simulation of Borehole Parameters for Coal Seam Gas Pre-Drainage

Borehole parameters are quite important for gas drainage. This paper studies the impact of borehole diameter and time on gas drainage and performs numerical simulation on the distribution of gas pressure under the conditions of different borehole diameters and drainage times. The simulation results reveal that, as the borehole diameter increases, the gas drainage volume increases along with it and the gas pressure decreases, but such effect on gas drainage is limited. In terms of drainage time, the longer the drainage time, the greater the drainage impact scope. Taking a gas pressure drop of 51% as the indicator of the effective pre-drainage radius, the distance from the point with a gas pressure drop of 51% to the position of the borehole is the effective pre-drainage radius. When the pre-drainage reached the 30th, 45th, 60th, 75th, and 90th day, the effective pre-drainage radius was 1.04m, 1.29m, 1.51m, 1.68m, and 1.82m respectively. According to the numerical simulation results, the effective pre-drainage radius varies with the pre-drainage time, and the fitting analysis of the two indicates that the relationship between the two can be described by a power function.

Discharge of lithium-ion batteries in salt solutions for safer storage, transport, and resource recovery

The use of lithium-ion batteries (LIBs) has grown in recent years, making them a promising source of secondary raw materials due to their rich composition of valuable materials, such as Cobalt and Nickel. Recycling LIBs can help reduce fossil energy consumption, CO2 emissions, environmental pollution, and consumption of valuable materials with limited supplies. On the other hand, the hazards associated with spent LIBs recycling are mainly due to fires and explosions caused by unwanted short-circuiting. The high voltage and reactive components of end-of-life LIBs pose safety hazards during mechanical processing and crushing stages, as well as during storage and transportation. Electrochemical discharge using salt solutions is a simple, quick, and inexpensive way to eliminate such hazards. In this paper, three different salts (NaCl, Na2S, and MgSO4) from 12% to 20% concentration are investigated as possible candidates. The effectiveness of discharge was shown to be a function of molarity rather than ionic strength of the solution. Experiments also showed that the use of ultrasonic waves can dramatically improve the discharge process and reduce the required time more than 10-fold. This means that the drainage time was reduced from nearly 1 day to under 100 minutes. Finally, a practical setup in which the tips of the batteries are directly immersed inside the salt solution is proposed. This creative configuration can fully discharge the batteries in less than 5 minutes. Due to the fast discharge rates in this configuration, sedimentation and corrosion are also almost entirely avoided.

Evaluating the Pollution Risk of Soil Due to Natural Drainage of Orange Peel: First Results

Orange peel (OP), the main residue of the citrus industry, is usually used for animal feeding and soil fertilisation if more advanced options are lacking. In areas with warm and dry climatic conditions, OP is land-spread for solar-drying on the fields, the leachate produced is a potential pollution factor for soil especially due to the release of organic matter; heavy rainfalls could even aggravate the hazard. Since literature does not report any quantitative evaluation of this risk, this study presents three OP drainage tests in lysimeters, where OP was left releasing leachate on a soil layer. A first test was carried out on raw OP naturally draining, while, in a second and a third test, a rainfall of 100 mm was applied on already drained and solar-dried OP, respectively. After drainage, raw OP reduced its initial volume by about 90% and the leachate production accounted only for about 20% of the initial volume. The simulated rainfall produced even lower volumes of leachate (2–3% of the initial biomass volume), in spite of the high rainfall volume and long drainage time after its application. The COD concentration in the leachate from the raw OP was significantly higher than those produced after simulated rainfall. However, the COD amount released to the soil was negligible. The lysimetric tests showed that the release of leachate occurs mainly during the first phase of drainage and that rainfall is absorbed and does not produce significant leaching. Overall, the risk of soil pollution due to the natural drainage of OP is negligible, due to both limited amounts of leachate and organic loading.