NeuroICU patients become febrile as often as regular ICU patients, and have about a 50% chance of having a fever of an entirely "central" orogon, which is to say "neither infectious nor inflammatory". The hyperthermia is still harmful, even if it is not associated with ventriculitis. A CSF cell count with more than about 1:100 WCC:RBC ratio is reassuring.
This is a summary of trials and guidelines related to neurology and neurosurgery, aimed at the CICM Part 2 exam candidate. The objective was to list the important studies, link to an authoritative analysis, and produce a pithy one-liner to help remember the main points.
As one might expect, the cardiovascular changes associated with normal agEing can be broadly described as "everything gets stiffer and less compliant". Though function is largely maintained with routine tasks, any added stressors or demands (like, for example, getting out of a chair) are met with a reduced cardiovascular response.
This equation describes the concentration of gases in the alveolus, and thus allows us to make educated guesses as to the effectiveness of gas exchange. One can use this to calculate the tension-based indices of oxygenation, such as A-a gradient or the a/A ratio (which is expressed as a percentage). The ABG machine frequently does this work for you, provided you have entered the FiO2 and have specified that your sample is "arterial". The result is usually reported aspO2(a/A).
Offered below is an organised list of summaries on the topic of renal failure and dialysis from the Critical Care Compendium, courtesy of LITFL. Given the mixture of topics, the ideal audience for this material is the final stage exam candidate pursuing dual CICM and ACEM fellowship qualifications.
Beta-blockers can be divided into selective and nonselective, depending on their affinity for β1 receptors where most of their desirable effects are exerted. Their main positive effects are a decrease in heart rate, decrease in cardiac contractility, and an increase in diastolic filling time, which results in a decrease in myocardial oxygen demand and an increase in coronary blood supply.They have additional positive antiarrhythmic effects. Negative (β2 receptor-mediated) effects consist of peripheral vascular vasoconstriction and increased bronchial smooth muscle tone.
The acidity of your precious bodily fluids is a carefully guarded parameter, and to allow this parameter to deviate out of a very narrow range would massively impair your capacity to continue living. Basic molecular services would break down. Cellular anarchy would ensue. In order for the ICU physician to wrest a form of order from this chaos, a reasonable grasp of basic acid-base chemistry should be expected. Perhaps that is the spirit of the syllabus item J1(ii), "explain the principles underlying acid-base chemistry".
Diffusion of respiratory gases is governed by Fick's Law and Graham's Law. As such, the main determinants of diffusion are the density of the gas, its molecular size, temperature, solubility and fluid viscosity, the partial pressure gradient between compartments, the surface area of the membrane and the speed at which the solvent is moving past it. The characteristic feature of this topic seems to be the large number of numerical values which, upon closer examination, are not particularly well supported by references, or which originate in ancient papers from the 1940s. Most textbooks are quite happy to plagiarise from one another and by some intergenerational cut-and-pasting, these values have been transmitted unchanged to the modern day. The CICM trainees are advised to regurgitate these numbers without questioning their origin.
Pregnancy is a state of well-tolerated parasitosis. In order to adapt to such an abnormal demand, the maternal organism undergoes a seres of complex changes, in order to survive the anatomically ridiculous task of pushing a fully formed human being through an pelvic outlet clearly meant for something with a much smaller brain. These changes are described below in the form of a point-form list, all the better to slot into viva practice and SAQ revision.
Nonresolving pneumonia may be merely atypical (not responsive to a course of commonly used antibiotics), or it may be inflammatory (eg. an idiopathic interstitial pneumonia like NSIP, a vasculitis, or a granulomatous disease like sarcoidosis), or it may be a condition which is entirely non-inflammatory (for example a pulmonary malignancy or alveolar proteinosis). This chapter patiently unpacks these possibilities, displaying their most striking features to help discriminate between them.
The parasympathetic nervous system is defined by the craniosacral origin of its nerve fibres, which come out of the brainstem and the S2-S4 sacral spinal cord segments. Preganglionic neurotransmission is nicotinic and postganglionic neurotransmission is muscarinic, both using acetylcholine. Ganglia are positioned closer to the target organ, and postganglionic fibres are short, in contrast to the sympathetic nervous system.
The physiological effects of infusing one litre of 0.9% sodium chloride solution into a patient are a volume expansion (by around 25% of the original infused volume) and a change in the biochemistry. The plasma osmolality and sodium remain the same, but the chloride may increase by up to 3 mmol/L. Additionally, the change in plasma oncotic pressure drives the excretion of the extra water by the mechanism of glomerulotubular balance.