Anomalous lateral diffusion of lipids during the fluid/gel phase transition of a lipid membrane.

A lipid membrane undergoes a phase transition from fluid to gel phase upon changing external thermodynamic conditions, such as decreasing temperature and increasing pressure. Extremophilic organisms face the challenge of preventing this deleterious phase transition. The main focus of their adaptive strategy is to facilitate effective temperature sensing through sensor proteins, relying on the drastic changes in packing density and membrane fluidity during the phase transition. Although the changes in packing density parameters due to the fluid/gel phase transition are studied in detail, the impact on membrane fluidity is less explored in the literature. Understanding the lateral diffusive dynamics of lipids in response to temperature, particularly during the fluid/gel phase transition, is albeit crucial. Here we have simulated the phase transition of a single component lipid membrane composed of dipalmitoylphosphatidylcholine (DPPC) lipids using a coarse-grained (CG) model and studied the changes of the structural and dynamical properties. It is observed that near the phase transition point, both fluid and gel phase domains coexist together. The dynamics remains highly non-Gaussian for a long time even when the mean square displacement reaches the Fickian regime at a much earlier time. This Fickian yet non-Gaussian diffusion (FnGD) is a characteristic of a highly heterogeneous system, previously observed for the lateral diffusion of lipids in raft mimetic membranes having liquid-ordered and liquid-disordered phases co-existing together. We have analyzed the molecular trajectories and calculated the jump-diffusion of the lipids, stemming from sudden jump translations, using a translational jump-diffusion (TJD) approach. An overwhelming contribution of the jump-diffusion of the lipids is observed suggesting anomalous diffusion of lipids during fluid/gel phase transition of the membrane. These results are important in unravelling the intricate nature of lipid diffusion during the phase transition of the membrane and open up a new possibility of investigating the most significant change of membrane properties during phase transition, which can be effectively sensed by proteins.

Unfractionated heparin versus enoxaparin for venous thromboembolism prophylaxis in intensive care units: a propensity score adjusted analysis.

Venous thromboembolism (VTE) is a common complication in hospitalized patients. Pharmacologic prophylaxis is used in order to reduce the risk of VTE events. The main purpose of this study is to compare the prevalence of deep vein thrombosis (DVT) and pulmonary embolism (PE) in patients admitted to the intensive care unit (ICU) who received unfractionated heparin (UFH) versus enoxaparin as VTE prophylaxis. Mortality was evaluated as a secondary outcome. This was a Propensity Score Adjusted Analysis. Patients admitted to neurology, surgical, or medical ICUs and screened with venous doppler ultrasonography or computed tomography angiography for detection of VTE were included in the analysis. We identified 2228 patients in the cohort, 1836 (82.4%) patients received UFH and 392 (17.6%) patients received enoxaparin. Propensity score matching yielded a well-balanced cohort of 950 (74% UFH, 26% enoxaparin) patients. After matching, there was no difference in prevalence of DVT (RR 1.05; 95% CI 0.67-1.64, p = 0.85) and PE (RR 0.76; 95% CI, 0.44-1.30, p = 0.31). No significant differences in location and severity of DVT and PE between the two groups were detected. Hospital and intensive care unit stay was similar between the two groups. Unfractionated heparin was associated with a higher rate of mortality, (HR 2.04; 95% CI, 1.13-3.70; p = 0.019). The use of UFH as VTE prophylaxis in ICU patients was associated with a similar prevalence of DVT and PE compared with enoxaparin, and the site and degree of occlusion were similar. However, a higher mortality rate was seen in the UFH group.

Tertiary treatment of coke-oven wastewater using suspended and immobilized whole live cells of constructed bacterial-microalgal consortium: modeling and optimization using ANN-GA hybrid methodology.

Coke-oven wastewater (CW), containing an array of toxic pollutants above permissible limits even after conventional primary and secondary treatment, needs a tertiary (polishing) step to meet the statutory limit. In the present study, a suitable bacterial-microalgal consortium (Culture C) was constructed using bacterial (Culture B: Bacillus sp. NITD 19) and microalgal (Culture A: a consortium of Chlorella sp. and Synechococcus sp.) cultures at different ratios (v/v) and the potential of these cultures for tertiary treatment of CW was assessed. Culture C4 (Culture B:Culture A = 1:4) with inoculum size: 10% (v/v) was selected for the treatment of wastewater since the maximum growth (3.08 ± 0.57 g/L) and maximum chlorophyll content (4.05 ± 0.66 mg/L) were achieved for such culture in PLE-enriched BG-11 medium. During treatment of real secondary treated coke-oven effluent using Culture C4 in a closed photobioreactor, the removal of phenol (80.32 ± 2.76%), ammonium ions (47.85 ± 1.83%), fluoride (65.0 ± 4.12%), and nitrate (39.45 ± 3.42%) was observed after 24 h. In a packed bed bioreactor containing immobilized C4 culture, the maximum removal was obtained at the lowest flow rate (20 mL/h) and highest column bed height (20 cm). Artificial intelligence-based techniques were used for modeling and optimization of the process.

Laparoscopic management of an ileal lipoma presenting with massive gastrointestinal haemorrhage.

Small bowel lipomas are benign submucosal neoplasm composed mainly of mature adipose tissue. Despite their rare occurrence, lipomas are the second most common benign tumour of the small intestine. These tumours are mostly small in size and remain clinically asymptomatic. However, larger lesions tend to be more symptomatic, presenting with complications such as intussusception, bleeding or obstruction. Definitive surgical or endoscopic intervention is indicated in such symptomatic lipomas. Herein, we describe a rare case of ileal lipoma presenting with ileo-ileal intussusception and a life-threatening haemorrhage that was managed by laparoscopic-assisted ileal resection.

Twitter Journal Club Impact on Engagement Metrics of the Neurocritical Care Journal.

BACKGROUND: Twitter journal clubs are a modern way of highlighting articles published in a scientific journal. The Neurocritical Care journal (NCC) initiated a bimonthly, Twitter-based, online journal club in 2015 to increase the outreach of its published articles. We hypothesize that articles included in the Neurocritical Care Society Twitter Journal Club (NCSTJC) had greater engagement than other articles published during the same time period. We also investigated the relationship between number of citations and Altmetric score to assess whether the enhanced online activity resulted in higher citations. METHODS: We gathered data in August 2020 on engagement metrics (number of downloads, Altmetric score, relative citation ratio, and number of citations) of all articles published in NCC between 2015 and 2018. Articles were analyzed into two groups: one featured in NCSTJC and the rest that were not (non-NCSTJC1), and the other comprised those that were not in NCSTJC but published under a similar category of articles as NCSTJC (non-NCSTJC2). Results were analyzed using descriptive statistics, and summary measures were used to report the spread. The groups were compared by using the Wilcoxon rank sum test, given that the data were not normally distributed. Spearman's rank correlation was used to assess correlation between Altmetric score and citations for the articles in the NCSTJC and non-NCSTJC groups. For comparison, the top ten cited articles in NCC were analyzed for similar correlations. RESULTS: Between 2015 and 2018, NCC published 529 articles, 24 of which were included in the Twitter journal club. A total of 406 articles were published in the same category as the category of articles selected for NCSTJC. The articles discussed as a part of NCSTJC had a statistically significant trend toward a higher number of downloads, Altmetric score, relative citation ratio, and number of citations than rest of the articles published in the journal during the same time period and the rest of the articles published in same categories. Three NCSTJC articles were among the ten most-cited articles published by NCC between 2015 and 2018. We did not find a correlation between Altmetric scores and number of citations in the NCSTJC or non-NCSTJC1 or non-NCSTJC2 group, but there was a strong correlation between these two variables in high performing articles when the top ten cited articles were analyzed. CONCLUSIONS: Scientific journals are evolving their social media strategies in attempt to increase the outreach of their articles to the medical community. Platforms such as Twitter journal clubs can enhance such engagement. The long-term influence of such strategies on the impact factor of a medical journal and traditional engagement metrics, such as citations, calls for further research.

Molecular confirmation & characterization of Rickettsia conorii in north India: A report of three cases.

Background & objectives: In India, spotted fever group rickettsiae (SFGR) are an underdiagnosed cause of acute febrile illness (AFI). The non-specific Weil-Felix test is the first diagnostic modality for the diagnosis of SFGR in many laboratories due to the lack of advanced diagnostic facilities in developing countries. The aim of this study was to detect SFGR using molecular methods in the patients, presenting with AFI in a tertiary care centre in north India. Methods: Consecutive patients (>14 yr of age) with AFI were enrolled over a six month period. Standard investigations for common pathogens causing AFI in India (malaria, dengue, scrub typhus, leptospirosis and enteric fever) were carried out. In patients who were negative for all of the above investigations, blood was subjected to polymerase chain reaction (PCR) targeting outer membrane protein A (ompA) gene of Rickettsia. Results: Of the 51 patients with an undiagnosed aetiology, three were positive by ompA PCR. Two of the PCR products produced good sequences and BLAST identification confirmed them as Rickettsia conorii. The sequences of R. conorii reported from south India clustered with two previously reported novel rickettsial genotypes. The study sequences clustered in a group different from that of Rickettsia spp. of the south Indian sequences reported earlier. Interpretation & conclusions: This study showed the existence of R. conorii in north India. Testing for SFGR may be included in the diagnostic workup of AFI for better disease management.

Clinical Profile and Predictors of Intensive Care Unit Admission in Pediatric Scrub Typhus: A Retrospective Observational Study from North India.

INTRODUCTION: Children with scrub typhus may present with one or more organ failures. Identifying the predictors of severe disease and need for pediatric intensive care unit (PICU) admission would help clinicians during outbreak seasons. MATERIALS AND METHODS: This observational study included 160 children admitted to the emergency department (ED) with scrub typhus confirmed by polymerase chain reaction (PCR) between January 2013 and December 2015. Demographic, clinical, and laboratory data were collected and predictors for PICU admission were identified. RESULTS: There was a seasonal trend with peak presentation in post-monsoon months between August and October. Mean (SD) age at presentation was 6.8 (3.2) years. Fever was present in all with a median (IQR) duration of 9 (6-11) days. Respiratory distress (42%), altered sensorium (24%), hepatomegaly (93%), splenomegaly (57%), and lymphadenopathy (54%) were other features. Rash and eschar were noted in 24% each. Thrombocytopenia (83%), hypoalbuminemia (63%), and hyponatremia (62%) were common laboratory abnormalities. Meningoencephalitic presentation was noted in 29%; acute kidney injury (AKI) (16%), acute respiratory distress syndrome (ARDS) (11%), and myocarditis (3%) were other organ dysfunctions. Sixty-six (41%) children required PICU admission. Intensive care needs include invasive ventilation (n = 27, 17%), vasoactive drugs therapy for hemodynamic support (n = 43, 27%), osmotherapy to treat raised intracranial pressure (n = 27, 17%), and renal replacement therapy (n = 3, 2%). Mortality was 8.8%. On multivariable analysis, lymphadenopathy, respiratory distress, shock, elevated lactate, and meningoencephalitis predicted the requirement of PICU admission. CONCLUSION: Scrub typhus presents with organ dysfunction during post-monsoon months. We identified predictors of intensive care in children with scrub typhus admitted to ED. CLINICAL SIGNIFICANCE: Our results would help clinicians identify severe cases and prioritize resources. HOW TO CITE THIS ARTICLE: Nallasamy K, Gupta S, Bansal A, Biswal M, Jayashree M, Zaman K, et al. Clinical Profile and Predictors of Intensive Care Unit Admission in Pediatric Scrub Typhus: A Retrospective Observational Study from North India. Indian J Crit Care Med 2020;24(6):445-450.

Acute ischemic stroke in a trauma cohort: Incidence and diagnostic challenges.

INTRODUCTION: Diagnosis of acute ischemic stroke is critical for acute intervention. Its diagnosis may be obscured in trauma patients due to confounding injuries. We report its incidence in trauma patients following their presentation at our institution. METHODS: Electronic charts of all acute trauma patients presenting to a designated level 1 trauma center emergency department between September 2012-November 2015 were screened and included in the study if they had a discharge diagnosis of acute ischemic stroke. Patient data were reviewed to identify the presence of neurologic deficit on initial triage, imaging type obtained (intracranial or extracranial) and time to diagnosis of stroke. RESULTS: Of 192 trauma patients screened, 11 were found to have acute ischemic stroke (5.7%). Patients were generally young (median age, 49 years) and predominantly males (n = 8). Presentation after vehicular crash was most frequent (n = 8 or 73%). Patients had predominantly skeletal injuries (n = 8 or 73%). Initial workup involved vascular imaging below the neck (n = 9), while only one had intracranial vascular imaging. When patients underwent cervicocranial vascular imaging, 64% (n = 7) had findings explaining the etiology of their stroke. None of the patients was diagnosed with acute ischemic stroke on admission. Its diagnosis was delayed by an average 1.8 days following presentation. CONCLUSIONS: Acute ischemic stroke in trauma patients was a frequent diagnosis albeit with delay. Routine craniocervical vascular imaging at the time of presentation could potentially facilitate early diagnosis. A prospective study with routine craniocervical vascular imaging in trauma patients will be needed to further explore this hypothesis.

Plant-lead interactions: Transport, toxicity, tolerance, and detoxification mechanisms.

Natural and human activities introduced an excess level of toxic lead (Pb) to the environment. Pb has no known biological significance and its interactions with plants lead to the production of reactive oxygen species (ROS). Pb and/or ROS have the potential to cause phytotoxicity by damaging the tissue ultrastructure, cellular components, and biomolecules. These damaging effects may possibly result in the inhibition of normal cellular functioning, physiological reactions, and overall plant performances. ROS play a dual role and act as a signaling molecule in plant defense system. This system encircles enzymatic and non-enzymatic antioxidative mechanisms. Catalase, superoxide dismutase, peroxidase, and enzymes from the ascorbate-glutathione cycle are the major enzymatic antioxidants, while non-enzymatic antioxidants include phenols, flavonoids, ascorbic acid, and glutathione. Pb removal from contaminated sites using plants depend on the plant's Pb accumulation capacity, Pb-induced phytotoxicity, and tolerance and detoxification mechanisms plants adopted to combat against this phytotoxicity. However, the consolidated information discussing Pb-plant interaction including Pb uptake and its translocation within tissues, Pb-mediated phytotoxic symptoms, antioxidative mechanisms, cellular, and protein metabolisms are rather limited. Thus, we aimed to present a consolidated information and critical discussions focusing on the recent studies related to the Pb-induced toxicity and oxidative stress situations in different plants. The important functions of different antioxidants in plants during Pb stress have been reviewed. Additionally, tolerance responses and detoxification mechanisms in the plant through the regulation of gene expression, and glutathione and protein metabolisms to compete against Pb-induced phytotoxicity are also briefly discussed herein.

Biochar potential in intensive cultivation of Capsicum annuum L. (sweet pepper): crop yield and plant protection.

BACKGROUND: The influence of various biochars on crop yield and disease resistance of Capsicum annuum L. (sweet pepper) under modern, high input, intensive net house cultivation was tested over the course of 2011-2014 in the Arava desert region of Israel. A pot experiment with Lactuca sativa L. (lettuce) grown in the absence of fertilizer employed the 3-year-old field trial soils to determine if biochar treatments contributed to soil intrinsic fertility. RESULTS: Biochar amendments resulted in a significant increase in the number and weight of pepper fruits over 3 years. Concomitant with the increased yield, biochar significantly decreased the severity of powdery mildew (Leveillula taurica) disease and broad mite (Polyphagotarsonemus latus) pest infestation. Biochar additions resulted in increased soil organic matter but did not influence the pH, electrical conductivity or soil or plant mineral nutrients. Intrinsic fertility experiments with lettuce showed that two of the four biochar-treated field soils had significant positive impacts on lettuce fresh weight and total chlorophyll, carotenoid and anthocyanin contents. CONCLUSION: Biochar-based soil management can enhance the functioning of intensive, commercial, net house production of peppers under the tested conditions, resulting in increased crop yield and plant resistance to disease over several years. © 2017 Society of Chemical Industry.

Geochemical Assessment of Fluoride Pollution in Groundwater of Tribal Region in India.

This study assessed the fluoride (F-) pollution in groundwater samples (n = 170) of tribal regions around Bailadila Iron Ore Mines [BIOM] Complex of Dantewada District, India. Weathering of carbonate and silicate clays were important geogenic sources of dissolved ions. A Piper diagram showed a Ca-HCO3 water type, with positive chloro-alkaline indices illustrating the occurrence of direct base-exchange reactions. The F- concentrations varied from 0.08 to 1.95 mg L-1 with a mean value of 0.9 ± 0.3 mg L-1. Only two groundwater samples showed F- concentrations > 1.5 mg L-1, the drinking water guideline established by the World Health Organization (WHO) and Bureau of Indian Standards (BIS). Factor analysis showed high loadings of HCO3- and F-, indicating alkaline conditions, favoring the dissolution of F- in the groundwater. The K fluor value is less than 10-10.6, indicating that the dissociation of fluorite is very slow. As a result, groundwater locations were under-saturated with respect to fluorite.

The effects of PPR on the reproductive health of Black Bengal goats and the possible role played by oxidative stress.

Outbreaks of Peste des petits ruminants (PPR) viral disease in Black Bengal goats were investigated from the middle Indo-Gangetic Plains of India. Clinical profile of PPR-affected flocks was recorded from four different outbreak sites of the region. The PPR outbreak was diagnosed serologically using commercially available sandwich ELISA kit. Relatively, low mortality rate (mean 26.75%) for PPR outbreak was recorded due to the endemic status of the disease. To understand the role of oxidative stress in PPR virus pathogenesis, various oxidant and antioxidant parameters in goats infected with PPR were estimated and compared with the uninfected/healthy goats of the same flock. The measured high level of pro-oxidant malondialdehyde (MDA) obtained from lipid peroxidation along with lower levels of anti-oxidants viz. superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) in PPR-affected Black Bengal goats suggests oxidative stress as one of the mechanism of pathogenesis of PPR virus. In addition, the correlation of oxidative stress due to PPR and the resulting reproductive disorders in the female goats were evaluated. The abortion in pregnant does observed during PPR outbreak was proportional to debility and oxidative stress manifested during PPR infection. The reproductive performance of recovered female goats in the period of 18 months of monitoring was significantly compromised in terms of kidding and twinning frequency. The mortality rate in kids born from PPR-recovered goats was significantly higher compared to those from health goats in the first 9 months post-recovery. From the present study, it may be concluded that together with the PPR virus, infection in goats and the resulting oxidative stress play a vital role for abortion and reduced post-reproductive performance in Black Bengal female goat.

A survey of blood pressure parameters after aneurysmal subarachnoid hemorrhage.

Purpose/aim: Blood pressure (BP) regulation is recommended following aneurysmal subarachnoid hemorrhage (aSAH) to prevent re-bleeding and to treat delayed cerebral ischemia. However, optimal BP thresholds are not well established. There is also variation with regard to the BP component (e.g. systolic vs. mean) that is targeted or manipulated. MATERIALS AND METHODS: An 18-question survey was distributed to physicians and advanced practitioner members of the Neurocritical Care Society. Respondents were asked which BP parameter they manipulated and what their thresholds were in different clinical scenarios. They were also asked whether they were influenced by the presence of incidental aneurysms. Answers were analyzed for differences in training background and treatment setting. RESULTS: There were 128 responses. The majority were neurointensivists (47 neurology and 37 non-neurology) and treated patients in dedicated neurointensive care units (n = 98). Systolic BP (SBP) was preferred over mean arterial pressure (MAP). Prior to aneurysm treatment, SBP limits ranged from 140 to 180 mm Hg. After aneurysm treatment, SBP limits ranged from 160 to 240 mm Hg. The maximum and minimum MAPs varied by as much as 50%. Nearly two-thirds of the respondents were influenced by the presence of incidental aneurysms. Training background influenced tolerance to BP limits with neurology-trained neurointensivists accepting higher BP limits when treating delayed ischemia ( p = .018). They were also more likely to follow SBP ( p = .018) and have a limit of 140 mm Hg prior to aneurysm treatment ( p = .001). CONCLUSIONS: There is large practice variability in BP management following aSAH. There is also uncertainty over the importance of incidental aneurysms. Further research could evaluate whether this variability has clinical significance.

Spinal Decerebrate-Like Posturing After Brain Death: A Case Report and Review of the Literature.

INTRODUCTION: Criteria for establishing brain death (BD) require absence of all brainstem-mediated reflexes including motor (ie, decerebrate or decorticate) posturing. A number of spinal cord automatisms may emerge after BD, but occurrence of decerebrate-like spinal reflexes may be particularly problematic; confusion of such stereotypic extension-pronation movements with brain stem reflexes may confound or delay definitive diagnosis of BD. We present a case in which we verified the noncerebral (ie, likely spinal) origin of such decerebrate-like reflexes. METHODS: Case report and systematic review of literature. RESULTS: A 63-year-old woman presented with large pontine hemorrhage and complete loss of cerebral function, including no motor response to pain. Apnea testing confirmed death by neurologic criteria. Thirty-six hours after BD declaration, during assessment for organ donation, she began to exhibit spontaneous and stimulus-induced stereotypic extension-pronation of the upper extremities. The similarity of these movements to decerebrate posturing prompted concern for retained brain stem function, but repeat neurological examination of cranial nerves and apnea testing did not reveal any cerebral responses. Electrocerebral silence on electroencephalogram and absent perfusion on nuclear medicine brain imaging further confirmed BD. Review of PubMed yielded 5 additional case reports and 4 cohorts describing cases of decerebrate-like extension-pronation movements presenting in a delayed fashion after BD. CONCLUSION: Extension-pronation movements that mimic decerebrate posturing may be seen in a delayed fashion after BD. Verification of lack of any brain activity (by both examination and multiple ancillary tests) in this case and others prompts us to attribute these movements as spinal cord reflexes and propose they be recognized within the rubric of accepted post-BD automatisms that should not delay diagnosis or necessitate confirmatory testing.

Pneumothorax as a Complication of Apnea Testing for Brain Death.

BACKGROUND: Pneumothorax is an under-recognized complication of apnea testing performed as part of the neurological determination of death. It may result in hemodynamic instability or even cardiac arrest, compromising ability to declare brain death (BD) and viability of organs for transplantation. We report three cases of pneumothorax with apnea testing (PAT) and review the available literature of this phenomenon. METHODS: Series of three cases supplemented with a systematic review of literature (including discussion of apnea testing in major brain death guidelines). RESULTS: Two patients were diagnosed with PAT due to immediate hemodynamic compromise, while the third was diagnosed many hours after BD. An additional nine cases of PAT were found in the literature. Information regarding oxygen cannula diameter was available for nine patients (range 2.3-5.3 mm), and flow rate was available for ten patients (mean 11 L/min). Pneumothorax was treated to resolution in the majority of patients (n = 8), although only six completed apnea testing following diagnosis/treatment of pneumothorax and only three patients became organ donors afterward. Review of major BD guidelines showed that although use of low oxygen flow rate (usually ≤ 6 L/min) during apnea testing is suggested, the risk of PAT was explicitly mentioned in just one. CONCLUSION: Development of PAT may adversely affect the process of BD determination and could limit the opportunity for organ donation. Each institution should have preventive measures in place.

Flow and thermal characteristics of high Reynolds number (2800-17,000) dye cell: simulation and experiment.

This paper presents computational and experimental studies on wavelength/frequency fluctuation characteristics of a high pulse repetition rate (18 kHz) dye laser pumped by a frequency-doubled Nd:YAG laser (532 nm). The temperature gradient in the dye solution is found to be responsible for wavelength fluctuations of the dye laser at low flow rates (2800

Dialysis-induced worsening of cerebral edema in intracranial hemorrhage: a case series and clinical perspective.

BACKGROUND: Intracranial hemorrhage (ICH) is not an uncommon complication of end-stage renal disease (ESRD), and may be complicated by cerebral edema. Hemodialysis (HD) may induce rapid osmolar and fluid shifts, increasing brain water content with the potential to worsen cerebral edema. The dangers of HD in patients with acute ICH have only been highlighted in isolated reports. METHODS: Case series and review of relevant literature. RESULTS: Two patients with ESRD presented with acute ICH (one with putaminal hematoma, the other with bilateral subdural hematomas) and developed fatal/near-fatal herniation during HD, associated with malignant worsening of cerebral edema. Both had interruptions in dialysis schedule prior to index event. Both were awake initially, but developed cerebral herniation syndrome toward the end of index HD, confirmed on imaging with worsening edema and effaced basal cisterns. In one case, herniation was reversed with hypertonic saline and hyperventilation, but in the other, the patient progressed to brain death despite these measures. We contrast these cases with a young patient with ESRD and large basal ganglia ICH who had elevated ICPs on admission, but safely underwent continuous veno-venous HD. CONCLUSIONS: Hemodialysis may worsen cerebral edema in the setting of ICH sufficient to precipitate cerebral herniation. Caution should be exercised when dialysing a patient with an acute mass lesion and reduced intracranial compliance, especially those in whom HD is new or not routine. Delaying HD till risk of edema is attenuated, or ensuring gradual urea removal (such as with continuous hemofiltration) may be advisable.