Non-blood Fluids Research Articles

Comparison between Blood, Non-Blood Fluids and Tissue Specimens for the Analysis of Cannabinoid Metabolites in Cannabis-Related Post-Mortem Cases

Cannabis use is widespread and is one of the most common drugs encountered in forensic-related analysis (antemortem and postmortem cases). However, the correlation between illicit cannabis use and death is rarely investigated, even while taking into consideration its role in the central nervous system depression and cardiovascular disorders. Few studies have discussed other non-blood specimens; this has brought a special interest in analyzing THC and its metabolites in different body parts in order to make precise forensic decisions. Herein, we are investigating the presence of Δ9-tetrahydrocannabinol (THC) and its metabolites:(11-hydroxy-Δ9-tetrahydrocannabinol (THC-OH) and 11-nor-Δ9- tetrahydrocannabinol-9-carboxy (THC-COOH)) in different postmortem specimens. Forty-three cases of bodily fluids and tissue post-mortem samples, previously found to be cannabinoid-positive were analyzed in the current investigation using alkaline hydrolysis followed by solid phase extraction and LC-MS/MS for THC and its metabolites concentration. In the current study, the highest median THC-COOH and THC-OH concentrations were detected in bile samples (1380 ng/mL and 8 ng/mL, respectively), while the highest THC median concentration was detected in gastric contents (48 ng/mL). This can be explained due to the postmortem distribution of blood to other bodily fluids and tissues and the accumulation in bile following multiple doses. Furthermore, high THC levels in gastric contents can be explained by the undergoing cycles of entero-hepatic circulation which resulted in a significant increase in THC in gastric contents. THC-COOH can be the best indicator to detect cannabinoids in toxicology studies, thus the inclusion of active THC metabolites is essential in death investigations. Additionally, THC-OH concentrations in postmortem cases could be influenced by body mass index. In this study, all types were specimens found to be suitable for testing cannabinoid metabolites, except for vitreous humor which showed low rates of detectability for cannabinoid metabolites.

328. Universal PCR Testing- Is It Worth It?

Abstract Background Universal PCR and Next Generation Sequencing (uPCR/NGS) is a major advancement in microbiology. It is a highly sensitive and specific test that amplifies ribosomal RNA in samples to detect bacterial and fungal pathogens. We investigated the uPCR/NGS tests sent from Henry Ford Health (HFH) and the effect obtaining this test had on patient care. Methods We completed a retrospective, observational study assessing all consecutive uPCR/NGS tests obtained from at HFH from 2016-2021. This included uPCR/NGS for detection of bacterial, fungal, mycobacterium tuberculosis (MTB), and non-tuberculosis mycobacterium (NTM). All samples were of non-blood fluids and tissue samples. Patients concurrent tissue cultures and blood cultures from day of uPCR/NGS, and within 6 months of obtaining the uPCR/NGS sample were evaluated. Primary outcomes included if uPCR/NGS testing resulted in a change of choice or duration of antibiotic therapy. Results At HFH, 226 uPCR/NGS tests from 111 samples were analyzed. This included 83 bacterial, 51 MTB, 51 NTM, and 41 fungal uPCR/NGS tests. Of the 226 uPCR/NGS tests, 31 tests (13.7%) resulted with positive result on uPCR/NGS. A total of 31 tests (13.7%) were ordered on a known culture positive sample, and 195 (86.3%) were ordered on a culture negative sample. Of samples sent from a culture positive sample, 7 (22.6%) resulted with positive uPCR/NGS results. 3 (42.9%) matched the tissue cultures, and 2 (28.6%) matched the patients’ blood cultures. None of the patients had any change in choice or duration of antibiotics based on uPCR/NGS results. Of the samples sent from a culture negative sample, 24 (12.3%) samples resulted with positive uPCR/NGS results. 2 (8.3%) matched a patient’s tissue cultures and none matched blood cultures. Change in antibiotic choice or duration occurred in 16 (17.6%) patients. The samples with the highest rates of change in management included cerebrospinal fluid (42.9%), brain tissue (36.4%), cardiac valvular tissue (27.3%), lymph nodes (25%), synovial fluid (20%). Figure 1:Flowchart of Results and Impact on Management Conclusion Our results show that uPCR/NGS has an overall low percent of impact in clinical outcomes, but it is a useful test in when used on a culture negative sample in certain sample types, along with a high index of suspicion for infection. Disclosures All Authors: No reported disclosures.

Transcending Blood—Opportunities for Alternate Liquid Biopsies in Oncology

Simple SummaryCell-free DNA—DNA that has been expelled from cells and can be isolated from blood plasma and other body fluids—is a useful tool in medicine, with applications as a biomarker in diagnosis, prognosis, disease profiling, and treatment selection. In oncology, the ease of access to the tumour genome is a major advantage of cell-free DNA, but while this has led to significant research in blood, other body fluids have not received equal attention. This review article summarises the current research into cell-free DNA in non-blood body fluids, highlighting its values and limitations, and suggesting the direction of future studies. We conclude that cell-free DNA from non-blood body fluids may provide additional information to supplement traditional biopsies, allowing informative and improved patient care across many cancer types.Cell-free DNA (cfDNA) is a useful molecular biomarker in oncology research and treatment, but while research into its properties in blood has flourished, there remains much to be discovered about cfDNA in other body fluids. The cfDNA from saliva, sputum, cerebrospinal fluid, urine, faeces, pleural effusions, and ascites has unique advantages over blood, and has potential as an alternative ‘liquid biopsy’ template. This review summarises the state of current knowledge and identifies the gaps in our understanding of non-blood liquid biopsies; where their advantages lie, where caution is needed, where they might fit clinically, and where research should focus in order to accelerate clinical implementation. An emphasis is placed on ascites and pleural effusions, being pathological fluids directly associated with cancer. We conclude that non-blood fluids are viable sources of cfDNA in situations where solid tissue biopsies are inaccessible, or only accessible from dated archived specimens. In addition, we show that due to the abundance of cfDNA in non-blood fluids, they can outperform blood in many circumstances. We demonstrate multiple instances in which DNA from various sources can provide additional information, and thus we advocate for analysing non-blood sources as a complement to blood and/or tissue. Further research into these fluids will highlight opportunities to improve patient outcomes across cancer types.

Perioperative visual loss.

Perioperative visual loss is an infrequent, devastating complication associated with spine surgery, most commonly from ischemic optic neuropathy. Current research and expert opinion indicate that it is associated with procedures that create elevated venous pressure in the head for prolonged periods of time. The largest case-control study on ischemic optic neuropathy associated with spine surgery found six independent and significant risk factors including male sex, obesity, Wilson frame use, longer operative times, greater blood loss, and a lower colloid to crystalloid ratio in the non-blood fluid administration. The American Society of Anesthesiologists developed a practice advisory for the prevention of this complication. In this setting, it is advisable to avoid significant physiologic and hemodynamic perturbations as much as possible, given the uncertainty of the pathophysiology. Because prevention of this complication cannot be guaranteed, consent for perioperative visual loss should be strongly considered in patients at high risk for this complication.

Perioperative visual loss and anesthetic management

Perioperative visual loss (POVL) is an uncommon complication primarily associated with cardiac, spine, and head and neck surgery that can have a potentially severe impact on quality of life. The largest multicenter case control study to date on POVL recently identified risk factors associated with ischemic optic neuropathy and prone spinal fusion surgery. This review will summarize these findings and the updated American Society of Anesthesiologists practice advisory on POVL to provide guidance on identification and management of high-risk patients undergoing prone spine surgery. Epidemiology data on POVL from national databases, POVL in robotic surgery, and posterior reversible encephalopathy syndrome as a newer cause of POVL will also be discussed. Risk factors associated with prone spinal fusion surgery and ischemic optic neuropathy identified in a large multicenter case-control study include male sex, obesity, use of the Wilson spinal frame, longer anesthetic duration, greater blood loss, and a lower percentage of colloid in the nonblood fluid administration. Strategies aimed at modifying risk factors for ischemic optic neuropathy associated with prone spinal fusion surgery that are extrinsic to the patient may decrease its incidence. Further research is needed to validate this concept.

Intraoperative Factors and the Risk of Respiratory Complications After Pneumonectomy

The potential effect of intraoperative factors on respiratory complications after pneumonectomy is still unclear. We conducted a retrospective cohort study; charts of 129 patients who underwent elective pneumonectomy at the University of Virginia were reviewed. Logistic regression was used to estimate the effect of anesthetic factors on the odds of at least one respiratory complication. Linear regression models were fit to assess the impact of these outcomes on length of stay (LOS). The incidence of respiratory complications in this cohort was 21%. In univariate analysis total nonblood fluids (p = 0.001), and the blood products packed red blood cells (p < 0.001), plasma (p < 0.001), and platelets (p = 0.044) were significantly associated with respiratory complications. In a multivariable logistic regression analysis, single unit transfusion of any blood product (packed red blood cells, plasma, or platelets) was identified as a major risk factor for respiratory complications after controlling for covariates (odds ratio = 1.47, 95% confidence interval 1.06 to 2.05). Respiratory failure and complications were closely related to LOS, increasing the LOS by a factor of 4.7 (95% confidence interval 3.51 to 6.18) and 3.5 (95% confidence interval 2.69 to 4.41), respectively. Blood product transfusion affects respiratory function and is an independent risk factor for respiratory complications after pneumonectomy.

Intravenous fluids for abdominal aortic surgery

Surgery on the abdominal aorta to treat aneurysms or occlusive disease is a major undertaking which requires intensive physiological support and fluid management. Blood products are often used but the main fluid replacement is with crystalloids or colloids. For years there has been controversy over which fluid is optimal and a number of studies have examined the subject. This is an update of a Cochrane review first published in 2000 and previously updated in 2002. To determine the effectiveness of different non-blood replacement fluids used in abdominal aorta procedures with a view to identifying the optimal fluid for use. The Cochrane Peripheral Vascular Diseases Group searched their Specialised Register (August 2009) and the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2009, Issue 3) for publications describing randomised controlled trials of non-blood replacement fluids in abdominal aortic surgery. In addition, the reference lists from retrieved trials were screened for further information about trials. Randomised controlled trials assessing the effects of at least one specific non-blood fluid used for replacement therapy in operations on, and confined to, the abdominal aorta. Data were extracted and then entered into the Review Manager software where statistical analyses were performed. Thirty-eight trials involving 1589 patients were included. Patients undergoing aortic surgery had various physiological parameters measured before and after their operation (these were cardiac, respiratory, haematological, and biochemical). Patients were randomised to a fluid type. This review demonstrated that no single fluid affects any outcome measure significantly more than another fluid across a range of outcomes. The death rate in these studies was 2.45% (39 patients). Despite the confirmed beneficial effects of colloids in this review, further studies are still required. There are no studies examining the effects of combination fluid therapy. The primary research outcome was death, for which results were limited; therefore, future studies should pay more attention to short-term outcomes such as minimising the need for allogenic blood transfusion, complications (organ failure), and length of stay in both the intensive care unit and hospital.

The influence of mannitol on the volume of fluid given to adult patients during cardiopulmonary bypass

During cardiopulmonary bypass, non-blood fluids are added to the circulation via the priming of the circuit. There is no standardisation of priming fluids between different cardiac centres, but most use a mixture of crystalloid and colloid. Mannitol, an osmotic diuretic, is often used in the prime with the aim of minimising renal damage. Although mannitol has no effect on renal function we have noticed that it reduces the amount of additional fluid given to maintain reservoir volume. This study aims at examining the effects of mannitol on fluid balance during cardiopulmonary bypass.

Are Cost of a Crystalloid-Based Volume Replacement Regimen Lower than of a Colloid-Based Volume Replacement Strategy?

Objective: Adequate volume therapy is a cornerstone for treating patients undergoing major surgery. The age-old crystalloid/colloid debate is still unsolved. The current push to reduce cost may also include considerations about the lowest cost for volume replacement therapy. Material and Methods: The study was designed as a prospective, randomized, single-institutional, clinical investigation in an urban, university-affiliated hospital. 100 patients scheduled for major abdominal surgery were randomized into 4 groups: either crystalloids (Ringer’s lactate (RL), n = 25), 6% hydroxyethyl starch (mean molecular weight (MW) 200 kDa, degree of substitution (DS) 0.5; HES 200, n = 25), a new 6% hydroxyethyl starch (MW 130 kDa, DS 0.4; HES 130, n = 25), or 4% modified fluid gelatin (MW 35 kDa, n = 25) were given until the 1st postoperative day (POD) to keep central venous pressure between 8 and 12 mm Hg. Cost for either volume replacement regimen were calculated, including acquisition cost of the substance as well as those of blood products and disposables used. Results: Even when infusing high doses of crystalloids (until 1st POD: 11,550 ± 850 ml), 10 patients showed orthostatic dysregulation. Gelatin-treated patients needed the largest amount of volume (3,350 ± 360 ml) of the colloid groups (HES 200: 2,350 ± 240 ml; HES 130: 2,590 ± 310 ml). Cost of blood products exceeded cost of nonblood fluids markedly (RL group: EUR 68.60 per patient), but did not differ between the four groups. Difference of total cost (fluids, blood products, disposables) between the crystalloid and the cheapest colloid group (HES 200) was EUR 12.60 per patient. Conclusion: By the choice of a particular volume replacement strategy, no big cost savings can be achieved in patients undergoing major abdominal surgery. Other aspects than only acquisition cost should be taken into consideration when deciding for a specific volume replacement strategy.

NONBLOOD FLUID RESUSCITATION: More Questions than Answers

Researchers and clinicians have been investigating and implementing various methods of resuscitation for victims of trauma for almost a century. Resuscitation medicine, as discussed during the International Resuscitation Research Conference, 41 includes several, yet related entities: the pathophysiology and reversibility of acute terminal states and clinical death; its treatment methods; and its delivery systems, including emergency medical services, critical care medicine, and both mobile and in-hospital intensive care units. 42 Fluid resuscitation is an integral, mandatory component to restoration of normal organ physiology in the setting of traumatic hemorrhage. Previous discussions of fluid resuscitation have included descriptions of the various solutions available for use (i.e., crystalloid versus colloid), suggested end points of resuscitation, and monitoring techniques available to guide the clinician through the resuscitation process, 7,9,16,17,54 but most have omitted the concept of damage control and discussion of the timing of fluid administration relative to hemostasis. After a review of the distribution of body fluids and the pathophysiology of fluid shifts in acute trauma, the fluids that are available for treatment in resuscitation from traumatic hemorrhage, and a brief discussion of suggested end points of resuscitation, whether occurring in the emergency medical phase or in the ICU, data are presented that serve as a guide to the future direction of resuscitation.

Carbon dioxide and oxygen partial pressure measurements in the cerebrospinal fluid in a conventional blood gas analyzer: analysis of bias and precision

Cerebrospinal fluid (CSF) gas tension measurements have been used as a marker of cerebral oxygenation in animal models and in human studies. Discrepancies in the measurement of PCO 2 and PO 2 in non-blood solutions by standard blood gas analyzers have been described. The CSF is a physiological non-blood fluid with an ability to carry only dissolved O 2 or CO 2. The aim of this experiment was to determine the bias and precision of CSF pCO 2 and pO 2 measurements of a contemporary blood gas analyzer and a continuous gas sensor. CSF from human patients was tonometered to known PCO 2 and PO 2 using standard calibration gases in a bubble tonometer. Following equilibration, a continuous measurement of the partial pressure of gases in the CSF in the tonometer solution was made using a calibrated Paratrend 7 gas sensor (Biomedical Sensors, Bucks., UK) inserted into the equilibration chamber of the tonometer and continuous CSF pH, PCO 2 and PO 2 measurements recorded at 1-min intervals. After equilibration, a 3-ml CSF sample was aspirated anaerobically from the tonometer and analysed in duplicate using an ABL 620 (Radiometer, Copenhagen) blood gas analyser. The measured pCO 2 and pO 2 from the ABL 620 blood gas analyser and the Paratrend 7 sensor were paired with the expected values to calculate bias and precision. Small offsets in PCO 2 and large offsets in PO 2 measurement were seen with the ABL 620 blood gas analyser. This study brings into question clinical decisions based on CSF PO 2 measurements. The implications for calibrating CSF sensors against CSF gas measurements are discussed.

Culture of abdominal aortic aneurysm contents. An additional series.

We evaluated the microbiologic nature of aneurysm contents. Aerobic and anaerobic cultures were taken from non-blood fluid, laminar thrombus, or ulcerated plaque within aortic aneurysms operated on during an eight-year period. Positive bacterial cultures were obtained from 22 (10.4%) of 211 aneurysms. Staphylococcus epidermidis was the most common organism recovered (12/22, 54%). Bacterial colonization of the arterial wall has a possible role in the pathophysiology of prosthetic graft sepsis. These data are valuable not only in choosing appropriate prophylactic antibiotics for aneurysm repair, but also in experimental efforts to develop an infection-resistant vascular graft by directing the antimicrobial characteristics of agents selected for binding to various prosthetic flow surfaces.

Aneurysm Contents as a Source of Graft Infection

During the past 5 1/2 years, cultures were taken from 68 to 151 surgically treated aortic aneurysms. These cultures were made from nonblood fluids, laminated clot, necrotic areas of the aneurysm wall, or ulcerated atheromatous plaques. Organisms were harvested from seven of the 68 cultures, including Staphylococcus, Escherichia coli, Pseudomonas, and hemolytic Streptococcus. Prophylactic antibiotics were used in all patients; however, the organisms cultured, excepting Streptococcus, were not sensitive to the chosen antibiotics. Three of the seven patients with a positive aneurysm culture died of causes unrelated to infection. Evidence of graft infection has not developed in four surviving patients with positive cultures. Knowledge of the presence of bacteria permitted massive antibiotic therapy based on organism sensitivity.