Aspiration Pressure Research Articles

Factors Affecting Aspiration Volumes of Back-flush Needles and Infusion Volumes of Vitrectomy Device

Purpose: The stability of the eye is important during vitrectomy which makes it important to balance the infusion rates (IR) and the aspiration rates (AR). The purpose of this study was to determine the effects of the IR from the vitrectomy device and the AR with back-flush needles. Methods: We compared the ARs of 25-gauge or 27-gauge back-flush needles manufactured by four companies. The AR of balanced salt solution (BSS), ethylene glycol (EG) mimicking subretinal fluid, and air was measured for each aspiration pressure. The IR of BSS and air was measured at different intraocular pressures (IOP). Results: The AR increased in proportion to the increase in the aspiration pressure, and it was positively correlated with the cross-sectional area of the soft tips and negatively with the total length of the soft tips. The IR of BSS and air increased in proportion to the increase in the IOP settings. The IR of BSS exceeded the AR of BSS and EG for all parameters, but the IR of air could be less than the AR at some settings. Conclusions: The results suggest that the aspiration of air may cause a collapse of the eye under some settings.

Phenomenological Study of the Atomization Process in Pre‐Filming Nozzles Typically Used for Steel Atomization

Liquid steel atomization using close‐coupled nozzles is highly dependent on the relationship between momentum flux ratio, gas–liquid ratio, aspiration pressure, and operating pressure of inert gases. A strong correlation between these parameters and the final powder must be assumed. Understanding these parameters, their influence on the process, and their interactions with each other is indispensable for efficient powder production. In particular, the industrial application of close‐coupled atomization nozzles, which develop a thin pre‐film on the nozzle tip, is not yet fully understood. A model experiment is presented to investigate interactions between the flow conditions of the gaseous and liquid phases, focusing on recirculation phenomena inside the atomization zone. The experiments show the influence of liquid and gas flow conditions on the spray geometry and the liquid core length, as well as the strong dependence of the liquid mass flux on the gas flow. The aspiration pressure below the liquid nozzle is sensitive to gas pressure and has a major influence on the development of the liquid core and the pre‐film, as it increases the liquid mass flux. For practical application, the results confirm an optimal operating point of interacting system parameters, which leads to high‐quality atomization with minimal use of resources.

Cell spheroid viscoelasticity is deformation-dependent

Tissue surface tension influences cell sorting and tissue fusion. Earlier mechanical studies suggest that multicellular spheroids actively reinforce their surface tension with applied force. Here we study this open question through high-throughput microfluidic micropipette aspiration measurements on cell spheroids to identify the role of force duration and spheroid deformability. In particular, we aspirate spheroid protrusions of mice fibroblast NIH3T3 and human embryonic HEK293T homogeneous cell spheroids into micron-sized capillaries for different pressures and monitor their viscoelastic creep behavior. We find that larger spheroid deformations lead to faster cellular retraction once the pressure is released, regardless of the applied force. Additionally, less deformable NIH3T3 cell spheroids with an increased expression level of alpha-smooth muscle actin, a cytoskeletal protein upregulating cellular contractility, also demonstrate slower cellular retraction after pressure release for smaller spheroid deformations. Moreover, HEK293T cell spheroids only display cellular retraction at larger pressures with larger spheroid deformations, despite an additional increase in viscosity at these larger pressures. These new insights demonstrate that spheroid viscoelasticity is deformation-dependent and challenge whether surface tension truly reinforces at larger aspiration pressures.

Aspiration tubing diameter is a key determinant of vacuum pressure and is associated with procedural outcome in mechanical thrombectomy for large vessel occlusion: An experimental and cohort study.

We (1) evaluated the effect of aspiration tubing diameter on intraluminal pressure and (2) compared thrombectomy outcomes in patients treated using small diameter tubing versus those treated using large diameter vacuum tubing. Intraluminal negative pressure was measured in a validated benchtop set up where consistency of negative pressure (inHg) was measured between static and dynamic aspiration. Static aspiration refers to activation of vacuum once the catheter is engaged with the clot. Dynamic aspiration refers to activation of vacuum when the catheter is slightly proximal to the clot. Four different sizes of vacuum tubing were trialed. We performed a retrospective analysis of consecutive patients who underwent mechanical thrombectomy. Procedural and functional outcomes were compared. The large diameter aspiration tubing held a consistent high negative pressure in static and dynamic aspiration (p = 0.152). Tubing types I to III were associated with a significant fall off in negative pressure between static and dynamic technique (p < 0.05). Two-hundred and five patients were included in the retrospective analysis; 124 (60%) underwent thrombectomy using small diameter vacuum tubing, and 81 (40%) using the large tubing. Mean thrombectomy time was shorter with the larger tubing [25.9 (17.9) minutes] versus the small tubing [37.5 (28.5) minutes, p = 0.002]. A greater proportion of patients had a thrombolysis in cerebral infarction score ≥2b in the group treated using the large tubing (78, 99%) than those with the small tubing (96, 78%, p < 0.001). Vacuum tubing diameter is linearly associated with intraluminal aspiration pressure. These findings have clinical significance as shown by increased recanalization rates and decreased thrombectomy times when large-diameter aspiration tubing is used. Shifting the paradigm toward a flow-based technique using large-bore vacuum tubing ought to be considered.

Successful ultrasound-guided ovum pick-up (OPU) and subsequent in vitro embryo production in a domestic cat

Ovum Pick Up (OPU) is a minimally invasive technique widely used in cattle and mares for oocyte retrieval, involving ultrasound-guided puncture of ovarian follicles. It has been demonstrated that this technique is safe for its repeated use in the same female without affecting her reproductive health, allowing for the retrieval of oocytes in individuals regardless of their reproductive status. The oocytes obtained through OPU can subsequently be used for in vitro embryo production (IVP) using assisted reproductive techniques (ARTs) or be cryopreserved in biobanks for their future use. Traditionally, the minimally invasive technique of choice performed in vivo in domestic and wild felines was LOPU (laparoscopic-guided ovum pick up). The present study was designed to explore if ultrasound-guided OPU in the domestic cat is safe and effective. In an initial series of ex vivo experiments (n = 92 ovaries, n = 434 oocytes), the effect of different aspiration pressures for oocyte collection was explored. These experiments identified 43 mmHg as the optimal aspiration pressure, resulting in the highest recovery rate and a favorable maturation and blastocyst rate. Subsequently, 16 grade I and II oocytes were retrieved by OPU and 101 oocytes were retrieved following ovariectomy and slicing. Sixteen oocytes obtained with each technique were subjected to in vitro maturation (IVM) and in vitro fertilization (IVF). A total of 14 presumptive zygotes were selected for in vitro culture (IVC) from each group (OPU and slicing), obtaining a cleavage rate of 57.1 % and 64.2 %, a morula rate of 28.5 % in both groups, and a blastocyst rate of 7.14 % and 14.2 % respectively. The hormonal stimulation protocol was well-tolerated, with no adverse effects observed. Moreover, no complications arose during the ovariectomy performed post-OPU. The use of this technique in domestic cats represents a significant step forward in terms of safety, replicability, and invasiveness, serving as a valuable model for its application in wild felids species. Additional research involving a greater number of animals is required to validate these encouraging findings.

Endotracheal Cuff Pressure in Different Positions in Patients Posted for Surgery under General Anaesthesia: An Observational Study

Background: The ideal endotracheal tube cuff pressure to prevent aspiration is 20-30cmH2O. Lower pressures will result in aspiration and high pressures will lead to tracheal mucosal injuries. Change in patient position may also lead to change in cuff pressures. Our study mainly aims at measuring the cuff pressures in supine, Trendelenberg, reverse Trendelenberg, neck flexion and rotation to one side. Methods: This prospective observational study was conducted after obtaining ethical clearance and patient consent. 50 patients of ASA Classes I and II were included. All patients were intubated with Romson cuffed endotracheal tubes of size 7.5mm for females and 8.5mm for males. The cuff was inflated and cuff pressure set at 28cm H2O using CuffillsR syringe. With head in neutral position, cuff pressure was measured in 15 degree Trendelenberg and reverse Trendelenberg positions. Using angle meter app, the angles were fixed for flexion, extension, and rotation to one side at 30 degrees. The cuff pressure was recorded after 120 seconds after placing the patient in all these positions. Results: The cuff pressure increased by 12.48cm H2O flexion and the cuff pressure increased to 33.22cm H2O in extension. The cuff pressure increased to 38.10cmH2O on rotation, increased by 10.58cmH2O from neutral position in Trendelenberg position and increased by 8.74cmH2O in reverse Trendelenberg position. Conclusion: The cuff pressure changed significantly in all the positions.

P-597 Pain intensity of oocyte retrieval of low and moderate number of oocytes is only mild, questioning the need of anesthesia and analgesia

Abstract Study question What is the pain intensity of oocyte retrieval (oocyte pick-up, OPU) without anesthesia and analgesia in women with low or medium number of follicles? Summary answer Pain intensity is only mild and is only slightly different in cycles with up to 5 aspirated oocytes and in repeated In-Vitro-Fertilisation (IVF) cycles. What is known already OPU is usually performed with anesthesia. However, OPU with anesthesia requires more treatment time and is more expensive. Previous studies have assessed the pain of OPUs without anesthesia in conventionally stimulated IVF using 15 to 19 gauge (G) aspiration needles and found high pain scores. Therefore, anesthesia is usually used in such IVF treatments. In contrast, in Natural cycle IVF (NC-IVF) OPU is commonly performed without anesthesia. The pain intensity of such OPUs and of OPUs of medium number of follicles has never been systematically analysed. Study design, size, duration A prospective, cross-sectional, multi-center observational study analyzing IVF cycles without anesthesia and analgesia was performed in seven IVF centers in Germany and Switzerland between January 2022 and March 2023. Women who performed one to ten NC-IVF or minimal stimulation IVF treatment cycles were enrolled. 518 aspirations were performed with 17G needles and 1772 with 19G or 20G needles. In total, 2290 cycles from 1039 patients were recorded. Participants/materials, setting, methods Pain score was assessed using a Visual Analogue Scale (VAS), graded 0 to 10 (0 = no pain; 10 = worst pain possible). Information about ovarian stimulation, number of collected oocytes, needle size, aspiration pressure and complications were recorded. A descriptive analysis was performed first, followed by a statistical evaluation using a linear mixed model to analyze the effect of the number of oocytes retrieved and of the number of cycles on the pain score. Main results and the role of chance The number of oocytes retrieved varied from 0 to 16 (interquartile range 1-2). The pain score varied from 0 to 10 with a median pain score of 3.0 (interquartile range 2-4), defined as “mild” pain. Compared to a reference value of aspirations with 1 oocyte, the pain score increased slightly by 0.5 points if no oocyte was retrieved, by 0.42 points if 2-5 oocytes were retrieved and by 1.14 points if ≥ 6 oocytes were retrieved (p &amp;lt; 0.001). Pain decreased slightly with repeated aspirations (-0.05 points per cycle) (p = 0.028). Needle size did not affect the pain scores. Seventeen vaginal and abdominal bleedings were recorded, two requiring hospitalization (&amp;lt;0.1%). Limitations, reasons for caution As only NC-IVF and minimal stimulation IVF cycles were analysed using mainly 19G and 20G needles, the results cannot be extrapolated to cycles with a high ovarian response and to aspirations using larger volume needles. Wider implications of the findings In case of one or few follicles OPU can be offered without anesthesia and analgesia to reduce aspiration time and cost. Trial registration number NCT05125497

An in-silico study on the mechanical behavior of colorectal cancer cell lines in the micropipette aspiration process

Cancer alters the structural integrity and morphology of cells. Consequently, the cell function is overshadowed. In this study, the micropipette aspiration process is computationally modeled to predict the mechanical behavior of the colorectal cancer cells. The intended cancer cells are modeled as an incompressible Neo-Hookean visco-hyperelastic material. Also, the micropipette is assumed to be rigid with no deformation. The proposed model is validated with an in-vitro study. To capture the equilibrium and time-dependent behaviors of cells, ramp, and creep tests are respectively performed using the finite element method. Through the simulations, the effects of the micropipette geometry and the aspiration pressure on the colorectal cancer cell lines are investigated. Our findings indicate that, as the inner radius of the micropipette increases, despite the increase in deformation rate and aspirated length, the time to reach the equilibrium state increases. Nevertheless, it is obvious that increasing the tip curvature radius has a small effect on the change of the aspirated length. But, due to the decrease in the stress concentration, it drastically reduces the equilibrium time and increases the deformation rate significantly. Interestingly, our results demonstrate that increasing the aspiration pressure somehow causes the cell stiffening, thereby reducing the upward trend of deformation rate, equilibrium time, and aspirated length. Our findings provide valuable insights for researchers in cell therapy and cancer treatment and can aid in developing more precise microfluidic.

Dissecting cell membrane tension dynamics and its effect on Piezo1-mediated cellular mechanosensitivity using force-controlled nanopipettes

The dynamics of cellular membrane tension and its role in mechanosensing, which is the ability of cells to respond to physical stimuli, remain incompletely understood, mainly due to the lack of appropriate tools. Here, we report a force-controlled nanopipette-based method that combines fluidic force microscopy with fluorescence imaging for precise manipulation of the cellular membrane tension while monitoring the impact on single-cell mechanosensitivity. The force-controlled nanopipette enables control of the indentation force imposed on the cell cortex as well as of the aspiration pressure applied to the plasma membrane. We show that this setup can be used to concurrently monitor the activation of Piezo1 mechanosensitive ion channels via calcium imaging. Moreover, the spatiotemporal behavior of the tension propagation is assessed with the fluorescent membrane tension probe Flipper-TR, and further dissected using molecular dynamics modeling. Finally, we demonstrate that aspiration and indentation act independently on the cellular mechanobiological machinery, that indentation induces a local pre-tension in the membrane, and that membrane tension stays confined by links to the cytoskeleton.

PRODUCTION OF Ni-HARD ALLOY POWDERS BY GAS ATOMIZATION

Ni-Hard cast iron materials are frequently used in equipment where high wear resistance is required in industrial applications. Generally, Ni-Hard is produced by conventional casting techniques. In this study, it was aimed to produce Ni-Hard powders to produce Ni-Hard cast iron materials with additive manufacturing techniques. To produce spherical and fine raw materials for additive manufacturing techniques, the gas atomization technique with a close-coupled nozzle system was preferred for the production of Ni-Hard powders. Ni-Hard alloy was melted in a high-frequency 10kW induction furnace under a protective atmosphere integrated into the gas atomization system. During the atomization process, 150 °C superheating was applied to prevent the liquid metal from freezing and clogging the melt delivery tube. In terms of the continuity of the atomization process, the negative pressure (aspiration pressure) values formed at the end of the melt delivery tube at different gas pressures were measured. An aspiration pressure of -50 mbar was obtained under an atomization pressure of 35 bar. Particle size distributions, hall flow behaviour and angle of repose properties of the produced powders were determined. Finally, the characterization of the powders was carried out by scanning electron microscopy. It was determined that the powders obtained as a result of atomization exhibited a spherical morphology and a narrow size range. The Hall flow rate test result of Ni-Hard powders was measured as 22 seconds for 50 g.

Effectiveness of comprehensive rhinoplasty on secondary nasal deformity with saddle nasal deformity after cleft lip surgery

To investigate the effectiveness of comprehensive rhinoplasty with autogenous costal cartilage grafting and prosthesis augmentation rhinoplasty in the treatment of secondary nasal deformity with saddle nasal deformity after cleft lip surgery. The clinical data of 96 patients with secondary nasal deformity with saddle nasal deformity after cleft lip surgery between September 2008 and January 2019 were retrospectively analyzed. There were 17 males and 79 females with an average age of 25.6 years (range, 17-38 years). Autogenous costal cartilage grafts were used to construct stable nasal tip framework and enhance the strength of alar cartilage. Nasal dorsum prostheses (39 cases of bulge, 45 cases of silicone prosthesis) or autogenous costal cartilage (12 cases) were used for comprehensive rhinoplasty. Visual analogue scale (VAS) score was used to evaluate the postoperative satisfaction subjectively, and nasal alar height symmetry index, nasal alar width symmetry index, nasal dorsum central axis deviation angle, and nasal columella deviation angle were calculated to evaluate objectively before and after operation. All patients were followed up 6 months to 8 years, with an average of 13.4 months. Nasal septal hematoma occurred in 3 patients after operation, which was improved after local aspiration and nasal pressure packing. Two cases had mild deformation of the rib cartilage graft of the nasal dorsum, one of which had no obvious deviation of the nasal dorsum and was not given special treatment, and one case underwent the cartilage graft of the nasal dorsum removed and replaced with silicone prosthesis. The incisions of the other patients healed by first intention, and there was no complication such as postoperative infection and prosthesis displacement. The nasal alar height symmetry index, nasal alar width symmetry index, nasal dorsum central axis deviation angle, and nasal columella deviation angle significantly improved after operation when compared with preoperative ones ( P<0.05). Postoperative subjective satisfaction evaluation reached the level of basic satisfaction or above, and most of them were very satisfied. Comprehensive rhinoplasty using autologous rib cartilage grafting to construct a stable nasal tip support, combined with dorsal nasal prosthesis or autologous cartilage implantation, can achieve good effectiveness on secondary nasal deformity with saddle nasal deformity after cleft lip surgery.

Intrarenal pressure study using 7.5 French flexible ureteroscope with or without ureteral access sheath in an ex-vivo porcine kidney model.

7.5F digital fURS and 9.5/11.5F ureteral access sheaths (UAS), both conventional (cUAS) and vacuum-assisted (vaUAS), are commercially available. Irrigation increases intrarenal pressure (IRP). This study analyzes the IRP with various irrigation rates using 7.5F fURS without UAS or with either cUAS or vaUAS in an ex-vivo porcine model. Pyelo-tubular backflow was also studied during these experiments. 11 porcine kidneys were used. 7.5F digital fURS was tested without UAS and with 9.5/11.5F cUAS and vaUAS. 6F pressure monitor catheters were placed into the upper and lower calyces. IRPs were recorded under different irrigation rates. When vaUAS was used, the air vent was either open or closed. 300mmHg aspiration pressure was chosen. Lastly, contrasted irrigation fluid was delivered until IRP reached above 30mmHg. Fluoroscopy images were obtained at 5mmHg intervals over this threshold to study the pyelo-tubular backflow. Using cUAS, IRP reached 30mmHg with irrigation rates between 60 and 70cc/min. Using vaUAS with vent closed, IRP never exceeded 10mmHg with irrigation up to 120cc/min. vaUAS with vent open performed marginally better than cUAS. fURS without UAS performed better than cUAS. Pyelo-tubular backflow became prominent at 40mmHg. In an ex-vivo porcine model, 7.5F fURS could be used safely without UAS with irrigation rates up to 120cc/min. The safety margin dropped to 60-70cc/min with cUAS. vaUAS with vent closed maintained IRP < 10mmHg with irrigation rates up to 120cc/min. Pyelo-tubular backflow was observed with IRP > 35mmHg.

Follicular flushing increases the number of oocytes retrieved: a randomized controlled trial.

Does follicular flushing increase the number of cumulus-oocyte complexes (COCs) retrieved compared to single aspiration? Follicular flushing significantly increases the number of COCs retrieved compared to single aspiration. On the basis of published meta-analyses, follicular flushing does not seem to increase the number of oocytes retrieved, the probability of clinical pregnancy, or that of live birth and has been associated with an increase in the duration of oocyte retrieval. It should be noted, however, that all the eligible randomized controlled trials (RCTs) in these meta-analyses have randomized patients into either single aspiration or follicular flushing. This study design might not allow the detection of the true effect of follicular flushing. Despite randomization, this might still be obscured, to an extent, by heterogeneity in patients, stimulation characteristics, and differences in the oocyte retrieval procedure. A prospective, single centre, RCT, including 105 patients was performed between July and December 2022. Eligible patients were those undergoing oocyte retrieval for ICSI, aged <43 years, with BMI 18-35 kg/m2. Patients with all types of ovarian response (low-normal-high), as assessed on the day of triggering final oocyte maturation, were included. Random allocation of the ovaries of each patient to either single aspiration or follicular flushing was performed on the day of oocyte retrieval, using a computer-generated randomization list. Patients could enter the study only once. All follicles from ovaries allocated to either follicular flushing or single aspiration, were aspirated by the same 16G double lumen needle, with a constant aspiration pressure of 190 mmHg, resulting in flow rate of 0.42 ml/s. In the ovaries allocated to the follicular flushing group, if a COC was not recovered in the initial aspirate of each follicle, follicular flushing was performed until a COC was retrieved, up to a maximum of five times. The primary outcome measure was the number of COCs retrieved. Secondary outcomes were oocyte recovery rate, oocyte maturation rate, fertilization rate, and rate of good quality embryos on Day 2. Values are expressed as a median (inter-quartile range). Significantly more COCs were retrieved in the follicular flushing as compared to the single aspiration group in all patients [5 (7) vs 2 (3), P < 0.001, respectively], as well as in patients with high [9 (3) vs 5 (4), P < 0.001, respectively], normal [5 (2) vs 2 (3), P < 0.001, respectively] and low [1 (1) vs 1 (1), P < 0.001, respectively] ovarian response. In patients with low ovarian response, no COCs were retrieved in 5.7% of the ovaries in the flushing group vs 42.8% of the ovaries in the single aspiration group (P < 0.001). The oocyte retrieval rate was significantly higher in the follicular flushing vs the single aspiration group, in all patients [88.9% (25.0) vs 45.5% (37.5), P < 0.001, respectively], as well as in patients with high [81.8% (15.9) vs 45.5% (22.2), P < 0.001, respectively], normal [85.7% (28.6) vs 40.0% (30.0), P < 0.001, respectively], and low [100% (0) vs 50.0% (100), P < 0.001, respectively] ovarian response. No significant difference was observed regarding maturation rate [85.2% (30.8) vs 100% (33.3), P = 0.78], fertilization rate [76.4% (50) vs 83.3% (50) P = 0.42], and the proportion of good quality embryos on Day 2 [83.3% (40) vs 100% (50), P = 0.62]. Similarly, no differences in the above variables were observed in patients with different types of ovarian response. Follicular flushing as compared to single aspiration was associated with a significant increase in the duration of oocyte retrieval in all patients [248 s (332) vs 135 s (164), respectively], as well as in patients with high [464 s (225) vs 237 s (89), P < 0.001, respectively], normal [248 s (108) vs 141 s (95), P < 0.001, respectively], and low [64 s (59) vs 48 s (10), P < 0.001, respectively] ovarian response. Although the current study design allows for a more accurate evaluation of the true effect of follicular flushing on the number of COCs retrieved, it does not permit the evaluation of its role on the probability of pregnancy. This is the first RCT to suggest that follicular flushing increases the number of COCs retrieved compared to single aspiration, independently of ovarian response. This implies that follicular flushing plays an important role in the optimization of oocyte retrieval. These results, however, need to be confirmed in future studies, in which an equal flow rate should be used during oocyte retrieval. No external funding was obtained for this study. There are no conflicts of interest to declare. NCT05473455. 15 July 2022. 27 July 2022.

Associations Between Dysphagia and Adverse Health Outcomes in Older Adults with Dementia in Intensive Care Units: A Retrospective Cohort Study.

Dysphagia is common in elderly patients with dementia and is one of the common clinical geriatric syndromes. It imposes a heavy burden on patients and their caregivers and is becoming an important public health problem. This study examined the association between dysphagia in older dementia patients in the ICU and the subsequent adverse health outcomes they experience. A retrospective analysis of adults (≥65 years) with dementia in ICUs of a Boston tertiary academic medical center was conducted. Using the International Classification of Diseases' Ninth and Tenth Revisions, dementia patients were identified. The study cohort comprised 1009 patients, median age 84.82 years, 56.6% female, predominantly White (72.9%). Patients were grouped based on swallowing function: dysphagia (n=282) and no-dysphagia (n=727). Dysphagia was identified via positive bedside swallowing screening. Primary outcomes were 90- and 180-day mortality, secondary outcomes included aspiration pneumonia, pressure injury, and delirium. Cohort characteristics were compared using the Wilcoxon rank-sum and chi-square tests. Dysphagia and outcomes correlations were examined via Kaplan-Meier survival analysis, Cox proportional-hazards regression models, logistic regression models, and subgroup analysis. After adjusting for covariates, the results from multivariate Cox proportional-hazards regression indicated that dysphagia was significantly associated with increased 90-day (HR=1.36, 95% CI=1.07-1.73, E-value=1.78) and 180-day (HR=1.47, 95% CI=1.18-1.82, E-value=1.94) mortality; the multifactorial logistic regression results indicated that dysphagia was associated with significant increases in pressure injury (OR=1.58, 95% CI=1.11-2.23, E-value=1.83) and aspiration pneumonia occurrence (OR=4.04, 95% CI=2.72-6.01, E-value=7.54), but was not significantly associated with delirium prevalence (OR=1.27, 95% CI=0.93-1.74). Dysphagia is likely to increase the risk of adverse health outcomes in older adults with dementia in ICU, and these adverse outcomes mostly include 90- and 180-day mortality, aspiration pneumonia, and pressure injury.

Comorbidities associated with 2-year mortality in adults with cerebral palsy in Japan.

To clarify whether the Whitney Comorbidity Index (WCI) is useful in Asian adults with cerebral palsy (CP) and whether aspiration pneumonia and pressure ulcers improved the prognostic significance of the WCI. This cohort study evaluated individuals aged at least 18 years with CP in Japan. We used Cox proportional hazards regression to analyse 2-year mortality rates. The predictive performance of the Charlson Comorbidity Index, Elixhauser Comorbidity Index, and WCI were compared as comorbidity assessment criteria. Aspiration pneumonia and pressure ulcers were added to the Cox models, and their impact on hazard ratios was determined. Of the 2232 adults with CP, 72 died during the 2 years. The model with a previously reported weighted WCI with aspiration pneumonia and pressure ulcers produced the best fit. Additionally, the hazard risk of 2-year mortality for an unweighted WCI score of at least 4 was 2.56; when CP-specific comorbidities were added, it increased to 8.94. This study showed that the WCI can be used in Asian adults with CP. Furthermore, assessing patient age, aspiration pneumonia, and pressure ulcers in addition to the WCI increased the predictive value for mortality. Our findings indicate that the WCI can promote valid comparisons between international populations. The Whitney Comorbidity Index (WCI) is useful among adults with cerebral palsy, irrespective of ethnic differences. Assessment of aspiration pneumonia and pressure ulcers increased the WCI predictive value. The WCI helps identify adults with cerebral palsy at risk of adverse outcomes.

P-771 Prospective comparison of different needle sizes (17G vs 18G) and aspiration pressures (110 vs 220 Hgmm) for egg collection in oocyte donors: randomized, pilot study

Abstract Study question How does higher aspiration pressure (220Hgmm) and thinner oocyte retrieval needle size (18G) affect egg retrieval rate, intervention duration, and post-operative pain in oocyte donors? Summary answer Egg retrieval rate and developmental potential did not vary according to needle thickness or aspiration pressure, whereas with higher aspiration pressure the intervention was shorter. What is known already Although transvaginal ultrasound guided egg collection has been successfully used for more than two decades, technical parameters of the egg collection are still not standardized and are often based on the manufacturer’s recommendations which have not been evaluated in a clinical setting. Only a handful of studies evaluated the use of thinner oocyte retrieval needle aiming at reducing ovarian trauma (Wikland 2011, Kushnir, 2013). Study design, size, duration After obtaining informed consent consecutive oocyte donors (n = 105) were prospectively assigned on the day of egg retrieval scheduling to three equal-sized groups (group 2: 17G needle, 220 Hgmm, group 1; 18G needle, 220 Hgmm, group 3: 17 G needle, 110 Hgmm) using two different oocyte retrieval needles (Kitazato, Japan) and two different aspiration pressures (Labotect, Germany). Oocyte donor age, BMI, baseline AMH, ≥14 mm and ≥10 mm follicular counts were not significantly different among groups. Participants/materials, setting, methods Oocyte donors were stimulated with GnRH antagonist protocol and oocyte maturation was triggered with GnRH agonist. Pre- and postoperative pain measured by visual analogue score (VAS:0-10) and duration of each egg collection performed under sedation was recorded. Retrieved mature eggs were assigned to previously matched recipients or electively vitrified for use in our centre’s egg bank. The developmental potential of retrieved eggs was evaluated by the fertilization and blastocyst formation rate of assigned, fresh oocytes. Main results and the role of chance As aspiration pressure and needle size decreased, the average duration of egg collection became longer (08:02, 09:36, 10:50 minutes, p = 0.002). Although postoperative pain scores were uniformly low, there was a marginally lower postoperative pain score in group 3, where a lower aspiration pressure was used (1.6±1.4, 1.9±1.9, 1±1.1, p &amp;lt; 0.0001). No oocyte donor experienced any significant postoperative complication. The number of retrieved eggs (27.3±12, 26.8±13.6, 26.1±12), oocyte retrieval rate per number of ≥ 14 mm follicles (104, 103, 104%), and the proportion of damaged eggs with ruptured zona pellucida (3.8, 2.7, 3.7%) were not significantly different among groups. Fertilization (72, 73, 73%) and blastocyst formation (51, 53, 46%) rates of injected fresh mature oocytes were not significantly different. Limitations, reasons for caution Due to the lack of similar studies, the size of each study group (n = 35) was determined by convenience instead of a previous sample size calculation. Wider implications of the findings Precise calibration of technical parameters of egg collection merits further attention and continuous monitoring, especially in hyper-stimulated oocyte donors where an excellent oocyte yield should be balanced against a shorter intervention, maximally reduced postoperative pain, and the lowest possible rate of complications. Trial registration number Not applicable

O-133 Follicular flushing increases the number of cumulus oocyte complexes retrieved. A Randomized Controlled Trial

Abstract Study question Does follicular flushing increase the number of cumulus oocyte complexes (COCs) retrieved compared to single aspiration? Summary answer Follicular flushing increases the number of COCs retrieved compared to single aspiration. What is known already On the basis of published meta-analyses, follicular flushing does not seem to increase the number of COCs retrieved and the probability of pregnancy. However, eligible RCTs in these meta-analyses are characterized by significant heterogeneity regarding the population studied, the needle type and lumen diameter, the aspiration pressure and the number of flushing attempts performed. Moreover, most of the studies do not offer information regarding the flow rate of the aspiration system used. A constant flow rate has been employed in a single RCT, in which a higher number of COCs was retrieved after follicular flushing compared with single aspiration. Study design, size, duration This is a single-center, randomized controlled trial, performed between July and December 2022. One hundred and five patients undergoing oocyte retrieval for intracytoplasmic sperm injection, aged &amp;lt;43 years, with BMI 18-35kg/m2 were included in the study. Random allocation of each ovary to flushing or single aspiration was performed by a study nurse on the day of oocyte retrieval, using a computer generated randomization list. Patients could enter the study only once. Participants/materials, setting, methods All follicles ≥11 mm were aspirated with the same double-lumen needle, using the same aspiration pressure (190 mmHg) to achieve a flow rate of 0.42 ml/sec. If no COC was found in the initial aspirate, flushing was performed in the corresponding group until a COC was retrieved, or up to a maximum of five times. The primary outcome measure was the number of COCs retrieved per ovary randomized. Values are expressed as median (interquartile range). Main results and the role of chance Significantly more COCs were retrieved per ovary randomized in the follicular flushing versus the single aspiration group, in all patients [5 (7) versus 2 (3), p &amp;lt; 0.001, respectively], in patients with high [9 (3) versus 5 (4), p &amp;lt; 0.001, respectively], normal [5 (2) versus 2 (3), p &amp;lt; 0.001, respectively] and low [1 (1) versus 1 (1), p &amp;lt; 0.001, respectively] ovarian response. No COCs were retrieved in 2.9% of the ovaries in the flushing group versus 16.2% of the ovaries in the single aspiration group (p &amp;lt; 0.001). The oocyte retrieval rate, which was defined as the ratio of COCs retrieved to the number of aspirated follicles ≥11 mm, was significantly higher in the follicular flushing versus the single aspiration group, in all patients [88.9% (25) versus 45.5% (37.5), p &amp;lt; 0.001, respectively], as well as in patients with high [81.8% (15.1) versus 45.5% (25.0), p &amp;lt; 0.001, respectively], normal [85.7% (28.6) versus 40% (30.0), p &amp;lt; 0.001, respectively], and low [100% (0) versus 50% (100), p &amp;lt; 0.001, respectively] ovarian response. No significant differences were observed regarding maturation rate, fertilization rate and the proportion of good quality embryos on day 2 in all patients as well as in patients with high, normal and low ovarian response. Limitations, reasons for caution The current study design, by randomizing ovaries instead of patients, eliminates heterogeneity attributed to multiple confounders and allows a more accurate evaluation of the true effect of follicular flushing on the number of COCs retrieved. However, it does not allow the detection of its effect on the probability of pregnancy. Wider implications of the findings This is the first RCT to show that follicular flushing increases the number of COCs retrieved compared to single aspiration, independently of ovarian response. The data presented suggests that follicular flushing plays an important role in increasing the efficacy of oocyte retrieval. Trial registration number NCT 05473455

Activation effects on the physical characteristics of T lymphocytes.

The deformability of leukocytes is relevant to a wide array of physiological and pathophysiological behaviors. The goal of this study is to provide a detailed, quantitative characterization of the mechanical properties of T cells and how those properties change with activation. We tested T cells and CD8+ cells isolated from peripheral blood samples of healthy donors either immediately (naïve population) or after 7days of activation in vitro. Single-cell micropipette aspiration was used to test the mechanical properties. T cells exhibit the general characteristics of a highly viscous liquid drop with a cortical "surface" tension, T cort. The time course of each cell entry into the micropipette was measured at two different aspiration pressures to test for shear thinning behavior. The data were analyzed in the framework of an approximate mechanical model of the cell deformation to determine the cortical tension, the cell volume, the magnitude of the initial cell entry, the characteristic viscosity μ o, and the shear thinning coefficient, b. Activation generally caused increases in cellular resistance to deformation and a broadening of the distribution of cell properties. The cell volume increased substantially upon cell activation from ∼200μm3 to ∼650μm3. Naive and activated T cells had similar mean cortical tension (∼150pN/μm). However, compared to naïve CD8+ cells, the cortical tension of activated CD8+ cells increased significantly to ∼250pN/μm. Dynamic resistance of naive CD8+ T cells, as reflected in their characteristic viscosity, was ∼870Pa and significantly increased to 1,180Pa after in vitro activation. The magnitude of the instantaneous projection length as the cell enters the pipette (L init) was more than doubled for activated vs. naive cells. All cell types exhibited shear thinning behavior with coefficients b in the range 0.5-0.65. Increased cell size, cortical tension, and characteristic viscosity all point to increased resistance of activated T cells to passage through the microvasculature, likely contributing to cell trapping. The increased initial elastic response of cells after activation was unexpected and could point to instability in the cell that might contribute to spontaneous cell motility.

Anisotropy of water dynamics confined in model silica material

Silica microfibers with highly oriented cylindrical mesopores embedded in alumina membrane were used as model system to characterize the water dynamics anisotropy at a picosecond timescale. To reach this goal, we first studied the optimal preparation conditions to obtain longitudinal silica mesopores orientation at macroscopic scale. Accordingly, we characterized the impact of ethanol content and aspiration pressure on the orientation and filling of the mesopores using scanning electron microscopy, transmission electron microscopy, small angle X-ray scattering, and dynamic vapor sorption. Based on the obtained results we selected the most appropriate sample as a model system. The model system was filled with water and used to characterize the dynamics of water molecules in parallel and perpendicular directions using quasi-elastic neutron scattering measurements collected in two orientations at two timescales (7 ps and 30 ps). The results revealed the anisotropy of water dynamics in the silica mesopores and highlighted a larger perpendicular diffusion coefficient compared to the parallel one at both timescales. This suggests that it may be more difficult for water molecules to move from one hydroxyl surface site to another compared to forming a hydrogen bond with a water molecule not adsorbed at the surface.

Effect of hematoma volume on the 30-day mortality rate of patients with primary hypertensive brainstem hemorrhage: a retrospective cohort study.

The purpose of this study is to investigate the effect of hematoma volume on the 30-Day Mortality Rate of patients with Primary Hypertensive Brainstem Hemorrhage (PHBH). Retrospective analysis was done on the clinical information of 74 patients who underwent treatment for primary hypertensive brainstem hemorrhage at the Department of Neurosurgery of the 908th Hospital of the Joint Logistic Support Force of the Chinese People's Liberation Army between January 2018 and December 2021. Both univariate and multivariate logistic regression were used to assess clinical signs and risk factors that affect 30-day mortality. In the 74 patients with primary hypertensive brainstem hemorrhage included in this investigation, 46 patients died and 28 patients survived. The mortality rate at 30 days was 62.16%. A statistically significant difference was seen (P < 0.001) in the results of the univariate analysis, which suggested that hematoma volume may be a factor affecting the prognosis of patients with hypertensive brainstem hemorrhage. Hematoma volume was further demonstrated to be a risk factor and an independent factor impacting death in patients with brainstem hemorrhage (P < 0.001) by multivariate logistic regression analysis (OR: 2.6, 95% CI: 1.7-3.9, P < 0.001 Crude Model, OR: 3.6, 95% CI: 1.7-7.7, P < 0.001 Multivariate-Adjusted Model). After adjusting for confounding variables such as age, body mass index, sex, history of diabetes mellitus, history of hypertension, admission GCS score, stereotactic aspiration, combined hydrocephalus, admission systolic and diastolic blood pressure, the hematoma volume was revealed to be an independent predictor of 30-day death in patients with brainstem hemorrhage. We discovered by smooth curve fitting that hematoma volume increased in a non-linear manner with 30-day mortality. The 30-day mortality rate did not alter significantly when the hematoma volume was less than 4 ml. When the hematoma volume was greater than 4 ml, the 30-day mortality rate increased rapidly, and when the hematoma volume was 10 ml, the 30-day mortality rate reached the maximum. Hematoma volume is an independent factor affecting 30-day mortality in patients with primary hypertensive brainstem hemorrhage. The severe and extensive neurological damage caused by primary hypertensive brainstem hemorrhage is highly unlikely to be fundamentally altered by a single protocol, and new avenues need to be explored scientifically and continuously.