Glucagon is a counterregulatory peptide hormone that is released from pancreatic α-cells in response to hypoglycaemia, as well as a range of other modulatory stimuli. Its main effects are experienced by the liver, which produces glucose in response - mainly as the result of accelerated glycogenolysis and gluconeogenesis.
Insulin is a pleiotropic anabolic hormone, a vasoactive peptide and an inotrope. Its main role is to facilitate the uptake of glucose by skeletal muscle and adipose tissue, as well as to regulate the supply of glucose from the liver.
The endocrine pancreas secretes polypeptide hormones, of which the most important are insulin glucagon and somatostatin. The main regulatory role of these hormones is in the regulation of the traffic of absorbed and stored nutrients, and the availability of these substances to the cells systemically. Lesser pancreatic hormones (eg. pancreatic polypeptide and ghrelin) are indirectly involved in the same system, by regulating appetite and satiety.
A brief, general discussion of this topic occurs in the Requred Reading section, in the chapter on the factors which influence the accuracy of CVP measurement. The transducer is zeroed at the level of the right atrium, which roughly corresponds to the 4th intercostal space in the mid-axillary line on a supine patient. This is the so-called "phlebostatic axis". Supine position is important: if you get your patient to stand up, the venous pressure in the feet ends up about 90mmHg. The neck veins collapse under the influence of atmospheric pressure; the dural sinuses inside the skull cannot collapse, and a negative pressure exists there (around -10mmHg).
For measurement of V/Q distribution, there are functional techniques and imaging techniques. Functional techniques include MIGET and the three-compartment model. Imaging techniques include radionuclide imaging (SPECT V/Q scans and PET scans), as well as MRI using IV gadolinium and 3He or 129Xe.
This soup is a concentrated separated product of multiple unremunerated donors, which is heated at 60 degrees for 10 hours. The Australian supplier is CSL. Not only albumin comes in the bottle. You get some sodium octanoate as well. The 20g of albumin has its own osmolality, and is dissolved in the electrolyte solution which supplies most of the remaining osmoles, but still in comparison to human plasma this solution is hypo-osmotic.
Blood transfusion complications can be divided into acute and delayed, and further classified as immunological (i.e. due to the incompatibility or immune reaction between the donor and recipient) and non-immunological (eg. the consequences of receiving a large volume of circulating donor cells, electrolytes, acidic carrier fluid and cytokines)
Packed red blood cells are so called because they are centrifuged and separated from whole blood, which increases their concentration. The normal haemoglobin concentration in a bag of PRBCs is 200g/L, or about 40-50g per each 200-250ml bag. As the consequence of storage, the fluid bathing these cells becomes quite acidic (pH around 6.5), with a high lactate, a high potassium (upwards of 200mmol/L) and low ionised calcium due to the presence of citrate.
FFP is the liquid portion of the blood, separated and frozen within 8 hours of collection; cryoprecipitate is what preciptates from it when it thaws; and prothrombinex is a factor concentrate separated by a process of adsorption onto an ion exchange substrate, followed by elution. Each has its own advantages and disadvantages.
Fibrinolytic drugs such as the recombinant tissue plasminogen activator alteplase catalyse the conversion of fibrin-bound plasminogen into plasmin, which then degrades the fibrin into soluble peptide fragments. Anti-fibrinolytic agents such as tranexamic acid act to prevent this step; for example tranexamic acid binds to lysine residues on plasminogen and prevents it from binding to fibrin, thus reducing the availability of substrate for endogenous tPa
The administration of vitamin K depends to a significant extent on whether the patient is bleeding or not. The patients with a high INR, even if they are at an elevated risk of bleeding, should only ever receive 0.5-2mg of Vitamin K; this is enough to return their INR to a more tolerable state. In contrast, the profusely bleeding warfarinised patient will require at least 5-10mg of Vitamin K.
Heparin is a heterogenous mixture of mucopolysaccharides, termed glycosaminoglycans. It is essentially a polymerised disaccharide, a starch. This drug is a staple of ICU anticoagulation, and one would do well to become very familiar with its properties.
Antiplatelet agents come in three flavours. COX inhibitors like aspirin prevent the synthesis of thromboxane A2 and therefore inhibit platelet activation. ADP receptor (P2Y12) antagonists like clopidogrel and prasugrel prevent aggregation by interfering with the activation of the glycoprotein IIb/IIIa complex. Direct GPIIb/IIIa receptor antagonists like tirofiban are competitive antagonists of fibrin and Von Willebrand factor.
This is a brief discussion of the reasoning behind the tests of coagulation function. Additionally, one may wish to review the coagulation cascade, if one (like myself) is unable to reliably recall its various details. An excellent resource for this information is PracticalHaemostasis.com