Approach To The Patient With Rectal Bleeding
John P. Papp in Endoscopie Control of Gastrointestinal Hemorrhage, 2019
Blood volume determination is the most accurate parameter for measuring the amount of blood loss. Even though the hematocrit does not immediately reflect changes in blood volume, it is valuable for following the rate of bleeding. An elevated blood urea nitrogen indicates resorption of blood in the upper intestinal tract. Luekocytosis is caused by any inflammatory process, such as infection, inflammation, or ischemia. However, sudden blood loss may stimulate an immediate bone marrow response with an elevation in the peripheral white-blood cell count. Screening tests for a possible bleeding diathesis should be performed with abnormalities sought in the prothrombin time and platelet count. Tests for the detection of occult blood in the stool must be a regular part of every patient examination. A positive result cannot be ignored. These tests are readily and easily performed by either the patient or the physician.
Principles of Clinical Pathology
Pritam S. Sahota, James A. Popp, Jerry F. Hardisty, Chirukandath Gopinath, Page R. Bouchard in Toxicologic Pathology, 2018
The test species influences test selection, most often because of sample volume limitations. Test selection for a mouse study must be carefully considered because an adult mouse has a blood volume of only approximately 2 mL, and collecting even half that volume cleanly is unlikely. However, it is usually possible to obtain enough blood from one mouse for standard hematology tests and a small subset of clinical chemistry tests that provides a broad screen of major organs and overall health status (e.g., urea nitrogen, ALT, total protein, albumin, and globulin). Another option is to designate one subset of animals in each group for hematology tests and a second subset of animals for clinical chemistry tests. Coagulation tests are typically not performed in mouse studies, but if they are indicated by the test article and study objectives, coagulation test sample requirements necessitate inclusion of a subset of animals specifically for that purpose. Similar issues concerning sample volume and test selection can arise in a rat study, especially if interim clinical pathology intervals are desired. It may be necessary to limit the tests done at interim intervals or to perform terminal blood collections under anesthesia prior to sacrifice and necropsy. Blood volume limitations that affect test selection and frequency in monkey (nonhuman primate; refers to cynomolgus monkey unless otherwise stated) studies are due to the combination of their relatively small size, especially young females, and the use of each animal for other tests requiring blood (e.g., pharmacokinetic analyses, antidrug antibody screens, and pharmacodynamic markers). In addition to the obvious effect on test selection and frequency, these multiple blood collections can and do significantly affect the results of many clinical pathology tests. Dogs are much less affected by multiple blood collections because of their size and ease of handling.
IVIM Models: Advantages, Disadvantages, and Analysis Pitfalls
Denis Le Bihan, Mami Iima, Christian Federau, Eric E. Sigmund in Intravoxel Incoherent Motion (IVIM) MRI, 2018
Using this method, the obtained value for fIVIM does not depend on T2 and the acquisition parameter TE. This method opens the path toward quantitative measurements of the blood volume fraction. The simultaneous measurement of T2 and the diffusion coefficients of the tissue and blood compartments also shows that T2 values can be separated for the two compartments and could also be used as disease biomarkers.
Minimally invasive capillary blood sampling methods
Published in Expert Review of Medical Devices, 2023
Michael S. F. Hoffman, James W. McKeage, Jiali Xu, Bryan P. Ruddy, Poul M. F. Nielsen, Andrew J. Taberner
Volumetric absorptive microsampling (VAMS) is a more advanced DBS sampling method for the remote collection of capillary blood. VAMS overcomes the spot area bias and homogeneity issues associated with the conventional DBS method [93]. The hydrophilic polymeric tips of VAMS samplers use capillary action to wick up a fixed volume blood sample (less than 50 µl) into a porous substrate, regardless of the haematocrit, in less than 4 seconds [93]. The blood volume absorbed is determined by the properties and amount of substrate. The VAMS sample is dried for 2 hours at room temperature and then sent via mail to a central laboratory for analysis. The VAMS sampler can be integrated into automated bioanalytical procedures in the laboratory. This simple, user-friendly dried blood collection approach reduces analysis costs, the number of clinical visits, and may be used to monitor study drug adherence.
Metabolomic analysis of CSF indicates brain metabolic impairment precedes hematological indices of anemia in the iron-deficient infant monkey
Published in Nutritional Neuroscience, 2018
Raghavendra Rao, Kathleen Ennis, Gabriele R. Lubach, Eric F. Lock, Michael K. Georgieff, Christopher L. Coe
Blood samples were obtained at 2-month intervals to track the iron status, and CSF samples were collected at 4-month intervals to compare the metabolomic profiles of those that developed IDA or remained IS. The blood collection was purposefully spaced at 2-month intervals to minimize the chance that frequent phlebotomy could contribute to the observed metabolomic effects.32 The collected blood volume (2–3 ml) represents <5% of the total blood volume even at the youngest ages (infants weigh approximately 500 g at birth). The mothers were trained to enter a specially designed holding apparatus for sample collection. Infants were briefly removed and blood samples were collected by femoral venipuncture, after which the infant was returned to the mother. These samples were used for hematology [Hgb and mean corpuscular volume (MCV)] and iron panels [Tf saturation and zinc protoporphyrin/heme (ZnPP/H)]. Hematological parameters were used to categorize infants as either IS or ID/IDA.
Intraoperative blood volume loss according to gestational age at delivery among pregnant women with placenta accreta spectrum (PAS): an 11-year experience in Songklanagarind Hospital
Published in Journal of Obstetrics and Gynaecology, 2022
Nuttaporn Maison, Athithan Rattanaburi, Ninlapa Pruksanusak, Rakchai Buhachat, Sathana Tocharoenvanich, Jitti Harnprasertpong, Nungrutai Sae-Aib, Yuthasak Suphasynth, Thiti Atjimakul, Aroontorn Pichatechaiyoot, Ingporn Jiamset, Kulisara Nanthamongkolkul
The anaesthesiologist staff, who attended in this difficult operation with a very high risk for massive intraoperative blood loss, all had worked in this field for at least 10 years. Four techniques for estimation of intraoperative blood loss were used: firstly, the blood volume in the suction canister, the second was blood volume in gauzes and swabs estimation, the third was an estimation of blood loss by visualisation from intraoperative field and operating table, finally, the staff checked if the haematocrit had changed from the preoperative baseline. Intraoperative fluid volume and blood replacement depended on total blood volume loss estimation from these four techniques, vital signs status and urine output evaluations.
Related Knowledge Centers
- Blood Cell
- Kidney Failure
- Hypertension
- Circulatory System
- Blood
- Red Blood Cell
- Hematocrit
- Blood Plasma
- Kidney
- Heart Failure