MRI and the Critically Ill
MRI and the Critically Ill: Restricted access to patients; Remote monitoring; MR compatible equipment; Safety of patients and staff; Getting the highest quality scan possible
Category Investigations
Osmolar Gap
Osmolar Gap: Osmolar gap = Osmolality (measured) - Osmolarity (calculated): NOTE: is a pragmatic clinical aid - the units are different (osmolality =mOsm/kg and osmolarity = mOsm/L) so it doesn't make mathematical sense!
Spinal Imaging
Spinal Imaging: CT is the best way to image the spine for bony injuries (will miss 6% of discoligamentous injuries). If suspected soft tissue or spinal cord injury -> patient requires an MRI
Spirometry
Spirometry
Stool specimens
OVERVIEW microscopy and culture is useful in community acquired diarrhoeal syndromes (not useful otherwise) in-hospital:— blood = ischaemic bowel or surgical cause— diarrhoea = rule out Clostridium difficile infection MICROSCOPY parasites, cysts, ova: giardia, cryptosporidium, blastocystis red and white cells:…
Synovial fluid analysis
Synovial fluid analysis: - appearance; WCC; RBC; microscopy + culture; protein; LDH; glucose; crystals
Ultrasound in Critical Care
Ultrasound in Critical Care: many roles; increasing applicability in emergency medicine and ICU
Urinalysis
CCC overview of urinalysis
Bleeding Time
Bleeding time
Bone Marrow Biopsy
Bone Marrow Biopsy: Confirm diagnosis. Allows therapy to be targeted. Needs to be done only, if the answer cannot be seen from peripheral blood already.
Coagulation Profile
OVERVIEW PROTHROMBIN TIME -> warfarin-> vitamin K deficiency-> liver disease-> DIC-> artefact: incorrect sampling or increased haematocrit (> 55%) ACTIVATED PARTIAL THROMBOPLASTIN TIME -> heparin-> DIC-> haemophilia-> liver disease THROMBIN TIME -> heparin-> DIC-> hypofibrinogenaemia-> fibrin degradation products FIBRINOGEN ->…
D-dimer
D-dimer specific for fibrin breakdownsensitivity = 95%specificity = 50%