Pressure Drainage Research Articles

Determination of the particularities of the hydraulic friction factor variation of collecting drainage pipelines

The object of the study in this paper is collecting perforated drainage pipelines, in particular, the determination of the hydraulic friction factor λdr, which significantly affects the parameters of the investigated pipes. Clarifying this issue will solve an important engineering problem – to develop a reliable method for hydraulic calculation of collecting perforated drainage pipes. As the main drawback of most of the available theoretical and experimental works on this topic is the insufficient consideration of the filtration characteristics of the surrounding soil and the material of the pipeline walls. Experimental studies of pressure drainage pipes with different design characteristics made it possible to find out the real picture of fluid flow in the pipe. Based on the research results, experimental dependences of λdr on the ratio of the fluid inflow velocity to the average flow velocity in the corresponding section (Uh/V), as well as on the design characteristics of the channel were obtained. The maximum possible flow that can be collected and passed by a collecting drainage pipeline with the specified design and filtration characteristics is determined. It is shown that a larger value of the specified ratio corresponds to larger values of λdr. This result can be explained by the effect of the attached flow on the main flow. Obviously, some energy is spent on the interaction of the attached and the main flow in the pipe, which leads to additional head losses. In the paper, dependencies were obtained for calculating the studied factor for collecting drainage pipelines. Using them in the calculation of drainage pipes will increase the reliability and efficiency of land reclamation systems, in which these pipelines are important structural elements

To the method of distribution drainage pipelines calculation with sloping groundwater level

A methodology for assessing the influence of the error value, which is included in the calculations of distribution pressure drainage pipelines in the case of a groundwater surface slope, is proposed in the paper. It is based on the previously obtained solutions of the system of differential equations describing the liquid movement with variable flow rate in distribution pressure drainage pipelines that operate at the horizontal level of the groundwater surface. The analysis is presented in dimensionless form. The influence of the groundwater level slope on the calculation results is estimated using the value of the relative flow variation in the initial section of the distribution pipeline and the generalized parameter of the distribution drain A, which takes into account its design and filtration characteristics. The obtained calculation formulas are quite simple and easy to use. The proposed method allows to determine the limits within which simplified dependencies for the calculation of drainage pipelines can be used, which are recommended for use at the horizontal groundwater level on the land reclamation site. At the same time, the error introduced into the calculations as a result of the adopted simplification is immediately determined. Corresponding graphs are presented in the paper to illustrate the obtained dependencies.

A longitudinal study of endoscopic naso-leakage negative pressure drainage for anastomotic leak after esophagectomy

Background and aimsPostoperative anastomotic leak is a threatening complication after esophagectomy. This study aims to evaluate the efficacy of endoscopic naso-leakage negative pressure drainage for anastomotic leak by longitudinal analyses, so as to focus on the intra-individual changes associated with the drainage in the disease course and to minimize the between-subject variations.MethodsWe conducted a retrospective longitudinal study. We hypothesize that maximum temperature (Tmax), maximum heart rate (HRmax), White blood cell count (WBC), and C reactive protein (CRP) had a two-piece linear spline growth curve with a notch at the time of drainage. Linear mixed-effects regressions were used to test the hypothesis of whether endoscopic naso-leakage negative pressure drainage changed the pattern of development of these clinical parameters with time.ResultsThirty patients were included, among which 83.3% were male, with a median age of 77 years. The median postoperative time to drainage was 16.5 days (range 6-66). Observations for Tmax, HRmax, WBC, CRP and PCT were 1366, 1372, 394, 296 and 290, respectively. After adjusting for age, sex, and body mass index, Tmax, HRmax, WBC and CRP showed similar pattern. There was no significant change over time before naso-leakage negative pressure drainage, while the four parameters all decreased significantly over time after naso-leakage negative pressure drainage.ConclusionsThe slope over time of Tmax, HRmax, WBC and CRP changed significantly after naso-leakage negative pressure drainage. Naso-leakage negative pressure drainage brought gradual decrease of these inflammatory parameters and could serve as a promising management for postoperative anastomotic leak after esophagectomy.

Effect of combining nano-silver dressing and vacuum sealing drainage with negative pressure treatment on patients with diabetic foot ulcers

This study investigates the efficiency of the combination of nano-silver dressing and vacuum sealing drainage (VSD) with negative pressure treatment on healing diabetic foot ulcers (DFU). A total of 100 patients with DFU admitted to our hospital between January 2022 and February 2023 were selected and randomly divided into a control group and an observation group, each consisting of 50 cases. Both groups received nano-silver dressings after debridement, but the observation group also underwent closed negative pressure drainage. Scores for wound granulation morphology and comfort were assessed before and after treatment. Efficacy rate, healing time, and clinical outcomes were evaluated before and after treatment. Serum levels of procalcitonin (PCT), high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), and cystatin C were measured before treatment and 30 days into treatment. After 10 days of treatment, the observation group showed a higher effective rate (96%) compared to the control group (88%). The observation group had better wound granulation morphology and comfort scores, shorter granulation and healing times, reduced hospitalization duration, and smaller wound areas than the control group. Both groups experienced decreased levels of IL-6, PCT, hs-CRP, and cystatin C after treatment. The observation group had lower levels of these markers compared to the control group. In conclusion, the combination of nano-silver dressing and VSD with negative pressure treatment improves the clinical efficacy of treating DFU. This approach reduces inflammation and promotes wound healing, as evidenced by improved wound scores, faster healing times, and reduced inflammatory marker levels.

The effect of unilateral chest drainage for transpulmonary pressure during mechanical ventilation

IntroductionChest tube drainage is usually performed through an underwater seal at a level of 10–20 cmH2O. Based on the definition of transpulmonary pressure, continuous chest drainage creates continuous negative pressure, decreasing pleural surface pressure and increasing transpulmonary pressure. We investigated how unilateral chest drainage could affect the tidal volume or driving pressure during mandatory mechanical ventilation.MethodsThis study was an experimental study using a lung-thoracic model and anesthesia ventilator. Tidal volume was set to 300 mL with pressure-controlled ventilation or volume-controlled ventilation. Left tidal volume and right tidal volume were measured independently using respirometers with positive end-expiratory pressure (PEEP) levels of 0, 10, and 20 cmH2O. Simultaneously, left negative pressure of the chest drainage was changed to 0, 10, and 20 cmH2O.ResultsIn all conditions, a tidal volume of 300 mL was achieved. In both pressure-controlled ventilation and volume-controlled ventilation, the left tidal volume increased with the application of chest drainage at 10 cmH2O when the PEEP level was 0 cmH2O, but left tidal volume decreased with the application of chest drainage at 20 cmH2O. Furthermore, when PEEP was 10 cmH2O, the left tidal volume decreased in proportion to the pressure of thoracic drainage. The right tidal volumes changed inversely with their counterpart left tidal volumes.ConclusionUnilateral chest drainage caused unbalanced ventilation of the left and right lungs regardless of pressure-controlled ventilation or volume-controlled ventilation.

Fast track surgery for children with congenital pseudarthrosis of the tibia: A prospective interventional study

ObjectiveThe purpose of this study was to explore the effect of fast-track surgery combined with a clinical nursing pathway on the recovery and complications of congenital pseudarthrosis of tibia. Methods82 children with congenital pseudarthrosis of tibia admitted from January 2019 to December 2020 were selected as the study subjects. The control group received routine clinical nursing pathway while the intervention group received a fast-track surgery combined with a clinical nursing pathway. The fasting and water deprivation time were arranged according to the pre operation time, and the accelerated rehabilitation nursing models such as progressive diet management, multi-functional analgesia, and early sequential functional exercise were given after the operation. After collecting data on perioperative diet, postoperative recovery, postoperative complications, and family satisfaction from both groups of patients in a large hospital in China, a comparative analysis was conducted. ResultsThe retention time of negative pressure drainage tube, urinary catheter and hospital stay in the intervention group were shorter than those in the control group (P < 0.05); The incidence of complications in the intervention group (5%) was significantly lower than that in the control group (21.42%) (P = 0.029). The family satisfaction of the intervention group (95.00%) was higher than that of the control group (80.95%). ConclusionStrengthening the concept of fast-track surgery nursing in the combined operation of congenital pseudarthrosis of tibia can shorten the hospitalization time of children, reduce the occurrence of postoperative complications and improve their family satisfaction.

Evaluation of a new magnetically suspended centrifugal neonatal pump in healthy animals using a veno-venous extracorporeal membrane oxygenation configuration.

The objective of this animal study was to evaluate the hemodynamic performance of a new centrifugal pump for extra-corporeal membrane oxygenation (ECMO) support in neonates. Six healthy swines were supported with veno-venous ECMO with the New Born ECMOLife centrifugal pump (Eurosets, Medolla, Italy) at different flow rates: 0.25, 0.5, 0.6, and 0.8L/min; three animals were evaluated at low-flows (0.25 and 0.5L/min) and three at high-flows (0.6 and 0.8L/min). Each flow was maintained for 4hours. Blood samples were collected at different time-points. Hematological and biochemical parameters and ECMO parameters [flow, revolutions per minute (RPM), drainage pressure, and the oxygenator pressure drop] were evaluated. The increase of the pump flow from 0.25 to 0.5L/min or from 0.6 to 0.8 L/min required significantly higher RPM and produced significantly higher pump pressures [from 0.25 to 0.5L/min: 1470 (1253-1569) versus 2652 (2589-2750) RPM and 40 (26-57) versus 125 (113-139) mmHg, respectively; p < .0001 for both - from 0.60 to 0.8L/min: 1950 (1901-2271) versus 2428 (2400-2518) RPM and 66 (62-86) versus 106 (101-113) mmHg, respectively; p < .0001 for both]. Median drainage pressure significantly decreased from -18 (-22; -16) mmHg to -55 (-63; -48) mmHg when the pump flow was increased from 0.25 to 0.5L/min (p < .0001). When pump flow increased from 0.6 to 0.8L/min, drainage pressure decreased from -32 (-39; -24) mmHg to -50 (-52; -43) mmHg, (p < .0001). Compared to pre-ECMO values, the median levels of lactate dehydrogenase, d-dimer, hematocrit, and platelet count decreased after ECMO start at all flow rates, probably due to hemodilution. Plasma-free hemoglobin, instead, showed a modest increase compared to pre-ECMO values during all experiments at different pump flow rates. However, these changes were not clinically relevant. In this animal study, the "New Born ECMOLife" centrifugal pump showed good hemodynamic performance. Long-term studies are needed to evaluate biocompatibility of this new ECMO pump.

Transcranial Photosensitizer-Free Laser Treatment of Glioblastoma in Rat Brain.

Over sixty years, laser technologies have undergone a technological revolution and become one of the main tools in biomedicine, particularly in neuroscience, neurodegenerative diseases and brain tumors. Glioblastoma is the most lethal form of brain cancer, with very limited treatment options and a poor prognosis. In this study on rats, we demonstrate that glioblastoma (GBM) growth can be suppressed by photosensitizer-free laser treatment (PS-free-LT) using a quantum-dot-based 1267 nm laser diode. This wavelength, highly absorbed by oxygen, is capable of turning triplet oxygen to singlet form. Applying 1267 nm laser irradiation for a 4 week course with a total dose of 12.7 kJ/cm2 firmly suppresses GBM growth and increases survival rate from 34% to 64%, presumably via LT-activated apoptosis, inhibition of the proliferation of tumor cells, a reduction in intracranial pressure and stimulation of the lymphatic drainage and clearing functions. PS-free-LT is a promising breakthrough technology in non- or minimally invasive therapy for superficial GBMs in infants as well as in adult patients with high photosensitivity or an allergic reaction to PSs.

Efficacy of Autologous Platelet-Rich Gel Combined with Negative Pressure Drainage in Patients with Diabetic Foot

Autologous platelet-rich gel (APG) has emerged as a novel treatment modality for diabetic foot, demonstrating potential in promoting wound healing and tissue repair. Negative pressure drainage has been shown to effectively remove wound exudates and facilitate wound healing. The objective of this research was to demonstrate the clinical efficacy of APG combined with negative pressure drainage in patients with diabetic foot. Following the preparation of platelet-rich plasma (PRP) gel, the influence of various temperatures and centrifugation speeds on gel properties was analyzed. PRP was assessed, and the slope and effective disaggregation rate of PRP were compared. A total of 30 healthy volunteers without diabetic foot were recruited as the control group and randomly assigned into three groups, with 10 participants in each group. The mean volume and concentration of PRP in the three groups were analyzed. A total of 30 patients with diabetic foot were selected as the observation group to analyze the therapeutic effects of APG combined with negative pressure drainage in patients with diabetic foot. The results showed that the prepared separated gel effectively isolated components in the blood, with a decrease in gel viscosity observed with increased centrifugation speed and temperature. The pH of the separated plasma remained stable. The plasma showed the best effects when immediately placed. At 0 h, 3 h, and 6 h, the PRP concentration in Group 1 was drastically superior to the other two groups (P &lt; 0.05). Regarding the slope of PRP, at 30 °C, the slope remained relatively stable; at 25 °C, the slope exhibited the largest variation. At 5 °C, the slope changed between 25 °C and 30 °C. The effective disaggregation rate was lowest when immediately placed, and it gradually increased with the prolongation of placement time. At 30, 60, 90, and 120 minutes of placement, the difference in effective disaggregation rate between 5 °C and 25 °C or 30 °C was considerable (P &lt; 0.05). The pH of PRP at 0 h, 3 h, and 6 h was weakly acidic, with inconsiderable difference in pH values among the three time periods (P &gt; 0.05). At 0 h, 3 h, and 6 h, the PRP concentration in Group 1 was markedly superior to the other two groups (P &lt; 0.05). In summary, the prepared separated gel effectively isolated PRP and the combination of APG with negative pressure drainage demonstrated remarkable therapeutic efficacy in patients with diabetic foot. The adoption of APG provides a personalized and innovative treatment option for diabetic foot patients, offering the potential to improve treatment outcomes.

Application of double-tube negative pressure drainage in repair of refractory wounds.

To observe the application effect of double-tube negative pressure drainage in the repair of refractory wounds. From January 2020 to April 2023, 50 patients undergoing refractory wound repair in the Department of Burn and Plastic Surgery of Jingjiang People's Hospital, Jiangsu were selected. According to different treatment methods, they were divided into an observation group and a control group, with 25 patients in each group. The observation group was treated with double-tube negative pressure drainage inside and outside the wound, while the control group was treated with negative pressure drainage inside the wound. By two-week observation, the wound healing status and complication rate after treatment, as well as the wound bacterial clearance rate, wound pain score and patient satisfaction 3, 7 and 14 d after treatment were compared between the two groups. Statistical analysis was carried out to determine the efficacy. After treatment for two weeks, the observation group showed a higher grade A healing rate (92%vs. 60%, X2 =7.018, P=0.008), a higher wound bacterial clearance rate (100%vs. 76%, X2 =6.818, P=0.03), a lower pain score (1.44±0.51vs. 2.36±0.49, t=-6.53, P<0.01), a higher patient satisfaction score (8.48±0.96vs. 6.64±0.95, t=6.80, P<0.01), and a lower complication rate (8%vs. 40%, X2 =7.018, P=0.008) compared with the control group. Double-tube negative pressure drainage has a significant application effect in the repair of refractory wounds. It can accelerate wound healing, shorten treatment time, effectively eliminate bacteria, relieve wound infection, reduce complications, alleviate pain and improve patient satisfaction. Therefore, the application, promotion and research of double-tube negative pressure drainage should be strengthened in clinical practice.

The Flow Law of Brine and Sediment Particles in Gas-Driven Brine Drainage in the Sediments of Salt Cavern Gas Storage

The geological resources of salt cavern gas storage in China are mostly complex layered salt beds with many thin inter-layers and high insoluble matter content. In the process of cavity-building by water-solution method, the insoluble matters in salt layers and inter-layers are peeled off and deposited at the bottom of salt cavern, occupying more than one-third of the whole cavity volume. These sediments have a large pore volume and strong compressibility, and they are filled with brine; as a result, they have great potential for gas storage. The research on the flow law of brine and sediment particles in gas-driven brine drainage in the sediments of salt caverns is the basis of utilizing the void space of sediments for gas storage. In this paper, salt cores of salt cavern gas storage wells in the Jintan District were selected, and the physical characteristics of insoluble sediments of the salt cores were analyzed. Then, a laboratory simulation device and experimental method of the gas-driven brine drainage were presented. Using artificial composite sediments in the experimental device, the following was tested: (i) the flow rates of brine and particles in the vicinity of the brine drain pipe in the sediments under different nitrogen displacement pressures, (ii) the relationship between the sand extraction amount and nitrogen displacement pressure of different brine drain pipes, (iii) the sand extraction amount of different sizes of particles with brine drain time, (iv) the cumulative sand extraction amount of different brine drain pipes, and (v) the effect of brine flow rate on the sand extraction amount. The results show that quartz, plagioclase, and ankerite account for 45–94% and clay accounts for 3.3–14.4% of the insoluble minerals of the salt cores from the Jintan District. The particle size distribution of the sediments ranges from 0.04 mm to 6 mm and can be divided into four ranges: &lt;0.5 mm, 0.5 mm~2 mm, 2 mm~4 mm, and &gt;4 mm. The mass percentage of each range is 37.9%, 36.5%, 17%, and 8.6%, respectively. There is a threshold pressure of the gas-driven brine drainage, where the larger the diameter of the sieve hole, the lower the threshold pressure, and the easier the pipe is to sand out. The diameter of the sieve hole has a great influence on the flow rate of the sediment particles near the brine drain pipe. The increase in nitrogen displacement pressure has a positive correlation with the flow rate of sediments near the pipe with 5 mm diameter sieve holes, but has little effect on the flow rate of sediments near pipes with 1.5 mm or 0.5 mm diameter sieve holes. The sand extraction amount is affected by factors such as the nitrogen displacement pressure, diameter of sieve hole, brine drain time, and brine flow rate in the process of gas-driven brine drainage. A higher nitrogen displacement pressure and brine flow rate lead to more sand extraction. A screen pipe with 1 mm diameter sieve holes is suggested to be used for sand control, the sieve holes are recommended to be machined in the shape of a trumpet with a small inlet section (i.e., 1 mm) and a large outlet end (i.e., 1.5 mm), and the brine flow rate is suggested to be about 30 m3/h when the brine removal is carried out in the sediments of salt cavern, which depends on the actual operation on site.

Uniportal thoracoscopic thorough debridement for tubercular empyema with abscess of the chest wall

Objective: To examine the feasibility and technical considerations of thorough debridement using uniportal thoracoscopic surgery for tuberculous empyema complicated by chest wall tuberculosis. Methods: A retrospective analysis was conducted on 38 patients who underwent comprehensive uniportal thoracoscopy debridement for empyema complicated by chest wall tuberculosis in the Department of Thoracic Surgery, Shanghai Pulmonary Hospital, from March 2019 to August 2021. There were 23 males and 15 females, aged (M(IQR)) 30 (25) years (range: 18 to 78 years). The patients were cleared of chest wall tuberculosis under general anesthesia and underwent an incision through the intercostal sinus, followed by the whole fiberboard decortication method. Chest tube drainage was used for pleural cavity disease and negative pressure drainage for chest wall tuberculosis with SB tube, and without muscle flap filling and pressure bandaging. If there was no air leakage, the chest tube was removed first, followed by the removal of the SB tube after 2 to 7 days if there was no obvious residual cavity on the CT scan. The patients were followed up in outpatient clinics and by telephone until October 2022. Results: The operation time was 2.0 (1.5) h (range: 1 to 5 h), and blood loss during the operation was 100 (175) ml (range: 100 to 1 200 ml). The most common postoperative complication was prolonged air leak, with an incidence rate of 81.6% (31/38). The postoperative drainage time of the chest tube was 14 (12) days (range: 2 to 31 days) and the postoperative drainage time of the SB tube was 21 (14) days (range: 4 to 40 days). The follow-up time was 25 (11) months (range: 13 to 42 months). All patients had primary healing of their incisions and there was no tuberculosis recurrence during the follow-up period. Conclusion: Uniportal thoracoscopic thorough debridement combined with postoperative standardized antituberculosis treatment is safe and feasible for the treatment of tuberculous empyema with chest wall tuberculosis, which could achieve a good long-term recovery effect.

Comparative study on the selection of drainage methods in posterior lumbar interbody fusion

ObjectiveTo compare and analyze the clinical effects of bilateral natural pressure drainage and negative pressure drainage after posterior lumbar interbody fusion (PLIF) to provide a reference for selecting drainage methods after lumbar surgery.MethodsA retrospective cohort study, 281 patients who underwent single-segment PLIF in our hospital from January 2017 to December 2020 and met the inclusion and exclusion criteria were included in the study, including 132 males and 149 females, aged 22–85 years, with an average of (53.62 ± 11.23) years. According to different postoperative incision drainage methods determined by the random number table method before surgery, they were divided into the natural pressure drainage group and negative pressure drainage group, both of which were bilateral drainage. The general observation indexes and perioperative-related indexes were recorded and analyzed.ResultsThere were 143 cases in the natural pressure drainage group and 138 cases in the negative pressure drainage group. There was no significant difference in age, gender, body mass index, disease type, blood pressure on the day of surgery, preoperative albumin, hemoglobin, platelet, prothrombin time, and intraoperative bleeding between the two groups (P > 0.05). The albumin on the first postoperative day in the natural pressure drainage group was higher than that in the negative pressure drainage group [(33.24 ± 3.52) vs. (32.17 ± 5.03), P < 0.05]; The hemoglobin on the first postoperative day in the natural pressure drainage group was higher than that in the negative pressure drainage group [(126.01 ± 15.03) vs. (115.19 ± 16.25), P < 0.01]; The drainage volume on the first postoperative day in the natural pressure drainage group was lower than that in the negative pressure drainage group [(93.25 ± 63.58) ml vs. (119.46 ± 54.48) ml, P < 0.01]; The total postoperative drainage volume in the natural pressure drainage group was lower than that in the negative pressure drainage group [(355.60 ± 189.69) ml vs. (434.37 ± 149.12) ml, P < 0.01]; The indwelling time of drainage tube in the natural pressure drainage group was lower than that in the negative pressure drainage group [(3.29 ± 1.17) d vs. (3.45 ± 0.97) d, P < 0.05]. There was no significant difference in platelet count on the first postoperative day, postoperative hospital stays, and complications (incision infection and hematoma) between the two groups (P > 0.05).ConclusionBilateral natural pressure drainage and negative pressure drainage can achieve good drainage effects after PLIF, but patients with natural pressure drainage have less loss of albumin and hemoglobin, less drainage volume, and shorter drainage tube indwelling time, which is worthy of clinical application.

Influence of Terrain Factors on Urban Pluvial Flooding Characteristics: A Case Study of a Small Watershed in Guangzhou, China

Urban roads in China, particularly low-lying areas such as underpasses, tunnels, and culverts, are highly vulnerable to the dangers of urban pluvial flooding. We used spatial interpolation methods and limited measured data to assign elevation values to the road surface. The road network was divided into tiny squares, enabling us to calculate each square’s elevation, slope, and curvature. Statistical analysis was then employed to evaluate the impact of terrain on flood characteristics in urban road systems. Our analysis reveals a strong spatial correspondence between the distribution of flood-prone points and the curvature parameters of the terrain. The spatial coincidence rate can reach 100% when an appropriate sampling scale is chosen. The presence of depressions is necessary but insufficient for forming flood-prone points. In lowland/gentle slope (LL/GS) areas with higher drainage pressure, we observe a significant negative correlation between flood-prone points and terrain curvature (Spearman’s r = 0.205, p &lt; 0.01). However, in highland/steep slope (HL/SS) areas, we find no significant correlation between them. Notably, terrain matters, but effective drainage is more influential in flood-prone areas. The maximum flood depth (MFD), submerged area, and ponding volume during urban pluvial flooding are constrained by depression topography, while the characteristics of the upstream catchment area also play a role in determining the MFD and flood peak lag time(FPLT). Larger upstream catchment areas and longer flow paths normally result in greater MFD and longer emergency response times/FPLT. Additionally, a higher flow path gradient will directly contribute to an increased flood risk (greater MFD and shorter FPLT). These findings have important implications for flood risk identification and the development of effective flood mitigation strategies.

Natural pressure drainage versus negative pressure drainage following transforaminal lumbar interbody fusion (TLIF) for the treatment of lumbar degeneration disease: a prospective cohort study.

To comprehensively compare the perioperative data and clinical outcomes of natural pressure drainage (NAPD) and negative pressure drainage (NEPD) following transforaminal lumbar interbody fusion (TLIF) for the treatment of lumbar degeneration disease. Between January 2021 and December 2021, 203 patients in our hospital who underwent single-or two-segment TLIF were assigned to the NAPD group (112 patients) or the NEPD group (91 patients) based on different postoperative drainage methods. Between the two groups, comparisons were made regarding the demographics, intraoperative and postoperative data, patient-reported outcomes, and complications. The NAPD group experienced less overall drainage and fewer postoperative drainage days (157.89 vs. 318.49ml/249.54 vs. 589.43ml, 2.00 vs. 2.67days/2.04 vs. 2.74days, P < 0.001) than the NEPD group. The NAPD group has a higher rate of overall hidden blood loss (HBL) than the NEPD group (63.98% vs. 51.90%/65.80% vs. 48.11%, P < 0.001); HBL, however, did not significantly differ between the two groups (P > 0.05). In two-segment surgery, the postoperative hemoglobin (HGB) levels were higher in the NAPD group (99.67 vs. 92.69g/L, P < 0.05), but there was no difference in single-segment surgery (P > 0.05). Regardless of whether single-or two-segment surgery was performed, the NAPD group had a lower HGB level loss (18.81% vs. 21.63%/26.35% vs. 32.08%, P < 0.05). There was no discernible difference between the two groups in the visual analog scale (VAS) scores for symptomatic epidural hematoma, postoperative body temperature, low back and leg pain, or incision infection (P > 0.05). NAPD did not increase postoperative complications but did significantly reduce postoperative drainage volume and the risk of anemia. We show that, when compared to NEPD, NAPD may be a better option for patients following TLIF.

Malignant cerebral edema after cranioplasty, a rare complication: case series and literature review.

The authors report on four cases of patients who underwent cranioplasty following decompressive craniotomy and subsequently died after surgery. Three of the patients had undergone craniotomy following trauma, while one patient had skull resorption. All four patients developed cerebral oedema immediately after surgery and exhibited significant craniofacial depression (also known as sunk flap syndrome). A negative pressure drainage system was utilized in all cases. One patient remained intubated, while the remaining three developed postoperative epilepsy and subsequently fell into a coma. Dilated and fixed pupils were observed in all patients, and computed tomography scans revealed diffuse cerebral oedema. Despite intensive resuscitation efforts and attempts at decompression, all four patients ultimately succumbed to their conditions. Fatal post-cranioplasty malignant cerebral oedema is a rare but very dangerous complication. Despite being rare, neurosurgeons should be aware that this fatal complication can occur after cranioplasty.

PULM9: Development of a Novel Cannula for Durable Venovenous Extracorporeal Membrane Oxygenation

Background: Fifteen million Americans suffer from chronic obstructive pulmonary disease (COPD). After failed optimal medical therapy, the only definitive treatment is lung transplantation, which is limited due to donor scarcity. Extracorporeal membrane oxygenation (ECMO) can be used in acute exacerbations of COPD or as a bridge to transplant for waitlisted COPD patients, but it is not currently suited for long-term respiratory support. Existing venovenous (VV) ECMO configurations often utilize a dual lumen cannula that is inserted into the jugular vein and is designed for short term use. While effective, dual lumen cannulas are associated with high resistance and malposition which limits blood flow, promotes cavitation, and increases blood trauma. Furthermore, patient ambulation is cumbersome because of the difficulty of securing the dual lumen cannula safely to the patient. A novel ECMO system that provides durable respiratory support could reduce morbidity and mortality in patients and facilitate ambulatory use. To this end, a dual lumen cannula that is attached to the heart and tunneled to a more ergonomic position could provide more durable, long term ECMO support. Here, we describe our initial efforts to develop a durable VV ECMO cannula with reduced resistance. Methods: A novel cannula for long-term VV ECMO support was developed using computer aided design. The cannula is designed for surgical attachment to the right atrium with the cannula’s drainage tip at the cavoatrial junction and the reinfusion port directed towards the tricuspid valve to minimize recirculation. Pressure drop was evaluated for the novel cannula, 28Fr, and 32Fr Crescent cannulas (MC3, Dexter, MI) for comparison (N≥5) in circuits primed with deionized water at ambient temperature. A Rotaflow (Maquet, Wayne, NJ) blood pump was operated at 2700-3625 RPM, and pressure drop was assessed for flow rates between 0.1 – 5 LPM. Porcine hearts were harvested from healthy pigs and utilized for ex vivo cannula fit studies. Water flow through the cannula into the right atrium was evaluated using videography. Results: The novel cannula drainage pressure drop (-12±1.1mmHg) was similar to the 28Fr Crescent (-13± 0.3mmHg) and 32Fr Crescent (-9±0.3mmHg) at 2LPM (Figure 1). Reinfusion pressure drop was similar between the novel cannula (22±1.2mmHg) and the 32Fr Crescent (21±0.4mmHg), and higher for the 28Fr Crescent (43±0.9mmHg) at 2LPM. Total pressure drop was similar between the novel cannula (33.4±1.2mmHg) and 32Fr Crescent (29.4±0.5mmHg) and higher for the 28Fr Crescent (57±1.0mmHg) at 2LPM. In ex-vivo heart studies flow through the novel cannula was directed towards the tricuspid valve and entered the right ventricle. Conclusions: Our novel cannula possesses an excellent pressure-flow profile, comparable to the largest-bore commercially available dual lumen cannulas. This novel cannula will enhance durability and ease of use for patients requiring durable mechanical respiratory support.Figure 1. Pressure Flow Curve for Novel VV ECMO Cannula

Application of modified alternate negative pressure drainage instrument after posterior lumbar fusion

To investigate the effect of modified alternate negative pressure drainage on postoperative outcomes after posterior lumbar interbody fusion (PLIF) surgery. This was a prospective study involving 84 patients who underwent PLIF surgery between January 2019 and June 2020. Of these patients, 22 had single-segment surgery and 62 had two-segment surgery. Patients were grouped by surgical segment and admission sequence:the observation group included patients with a single-segment surgery, and the control group included patients with a two-segment surgery. Natural pressure drainage was given to 42 patients in the observation group (modified alternate negative pressure drainage group) after surgery, which was then changed to negative pressure drainage after 24 hours. In the control group, 42 patients were given negative pressure drainage after surgery, which was then changed to natural pressure drainage after 24 hours. The total drainage volume, drainage time, maximum body temperature at 24 hours and 1 week after surgery, and drainage-related complications were observed and compared between the two groups. There was no significant difference in operative time and intraoperative blood loss between the two groups. The postoperative total drainage volume was significantly lower in the observation group (456.69±124.50) ml than in control group (572.36±117.75) ml, and the drainage time was significantly shorter in the observation group (4.95±1.31) days than in the control group (4.00±1.17) days. Maximum body temperature at 24 hours after surgery was similar in both groups (37.09±0.31)°C in the observation group and (37.03±0.33)°C in the control group, while on the 1st week after surgery, it was slightly higher in the observation group (37.05±0.32)°C than in the control group (36.94±0.33)°C, but the difference was not significant. There were no significant differences in drainage-related complications, with one case(2.38%) of superficial wound infection in the observation group and two cases(4.76%) in control group. Modified alternate negative pressure drainage after posterior lumbar fusion can reduce the drainage volume and shorten the drainage time without increasing the risk of drainage-related complications.

Effect of sinus resection combined with vacuum-assisted closure on sacrococcygeal pilonidal sinus.

This study was aimed at investigating the effect of sinus removal combined with vacuum-assisted closure in the treatment of sacrococcygeal pilonidal sinus. From January 2019 to May 2022, 62 patients with sacrococcygeal pilonidal sinus were treated and their information was collected at our hospital. These patients were randomly divided into two groups: an observation group (n = 32) and a control group (n = 30). The control group underwent a simple sinus resection and suture, while the observation group received a sinus resection combined with closed negative pressure drainage of the wound. A retrospective analysis of the data obtained was conducted. Perioperative indicators, clinical efficacy, postoperative pain, complications, aesthetic effects, and satisfaction scores at six months after the operation were compared between the two groups, and the recurrence rate at six months after the operation was recorded. Through this study, we found that the observation group had significantly shorter surgery time, hospital stay, and return time compared with the control group (P < 0.05). Additionally, the observation group had a higher overall recurrence rate (ORR) of 100.00%, which was significantly better than the control group's ORR of 86.67% (P < 0.05). The visual analog scale (VAS) score at 6, 12, and 24 h after the operation was significantly lower in the observation group compared with the control group (P < 0.05). Although the differences were not significant (P > 0.05), the observation group had decreased white blood cell, neutrophil, and C-reactive protein levels after the operation. Moreover, the total occurrence rate of postoperative complications in the observation group was significantly lower (6.25%) than that of the control group (26.67%; P < 0.05). The observation group also had significantly lower scores on the postoperative scar scale and higher satisfaction scores than the control group (P < 0.05). However, there was no significant difference in the postoperative recurrence rate between the two groups (P > 0.05). Our study demonstrated that sinus resection combined with vacuum-assisted closure was more effective in treating sacrococcygeal pilonidal sinus compared with simple sinus resection and suture. This approach significantly reduced surgery time, hospital stay, and return time. It also effectively relieved postoperative pain, reduced the occurrence of postoperative complications, resulted in smaller postoperative scars, and yielded better aesthetic outcomes and higher patient satisfaction.

Study on Secondary Brine Drainage and Sand Control Technology of Salt Cavern Gas Storage

Geological conditions of salt cavern gas storage in China are characterized by dominantly layered salt layers with a high content of insoluble mudstone. After the water leaching of the salt layer, a large amount of sediment accumulates at the bottom of the gas storage cavity. During the gas injection process, only the clean brine above the sediment can be expelled, leaving a brine layer of 2–5 m and a large amount of brine in the pore space of the sediment. To increase storage capacity, it is urgent to explore the secondary gas injection and brine drainage technology to further expel residual brine in pores of the sediment at the cavern bottom. The sediment is relatively loosely packed and is composed of mudstone particles, which easily migrate and block the brine withdrawal pipe. In this paper, firstly, the mineral composition, particle size and distribution characteristics of the sediment at the bottom of the salt cavern are fully understood by XRD and sieve analysis methods. Then, a lab simulation device suitable for secondary gas injection and brine drainage of a high-salinity salt cavern with a diameter and height of 25 cm was designed and built. A screen sand control experiment, a gravel pack artificial wall sand control experiment and chemical cementing sand were simulated. The effects of gas injection, brine drainage pressure, brine layer height and insoluble particle size on sand production and liquid drainage were studied. The influence factors of brine withdrawal on the sand control in secondary brine drainage were intensively investigated, and finally, the gravel pack artificial wall sand control technology system was recommended. The optimal construction parameters for secondary brine discharge are recommended as follows: Under the condition of gravel packing with the same particle size, the trend of sand content with different artificial wall thicknesses is not obvious, and a 2 cm wall thickness is the best in the overall experiment, corresponding to 28 cm in the field. The larger the particle size of the gravel pack, the better the sand control, and the best gravel size is 10–20 mesh. The injection pressure should be as low as possible.