The retina (from Latin: rete "net") is the innermost, light-sensitive layer of tissue of the eye of most vertebrates and some molluscs. The optics of the eye create a focused two-dimensional image of the visual world on the retina, which then processes that image within the retina and sends nerve impulses along the optic nerve to the visual cortex to create visual perception. The retina serves a function which is in many ways analogous to that of the film or image sensor in a camera. The neural retina consists of several layers of neurons interconnected by synapses and is supported by an outer layer of pigmented epithelial cells. The primary light-sensing cells in the retina are the photoreceptor cells, which are of two types: rods and cones. Rods function mainly in dim light and provide monochromatic vision. Cones function in well-lit conditions and are responsible for the perception of colour through the use of a range of opsins, as well as high-acuity vision used for tasks such as reading. A third type of light-sensing cell, the photosensitive ganglion cell, is important for entrainment of circadian rhythms and reflexive responses such as the pupillary light reflex. Light striking the retina initiates a cascade of chemical and electrical events that ultimately trigger nerve impulses that are sent to various visual centres of the brain through the fibres of the optic nerve.
A systematic review of the literature in 2008 demonstrated no difference in outcomes between the use of intermittent hemodialysis and continuous venovenous hemofiltration (CVVH) (a type of continuous hemodialysis). Among critically ill patients, intensive renal replacement therapy with CVVH does not appear to improve outcomes compared to less intensive intermittent hemodialysis. However, other clinical and health economic studies demonstrated that, initiation of CRRT is associated with a lower likelihood of chronic dialysis and was cost-effective compared with IRRT in patients with acute kidney injury. Complications
Metabolic acidosis, hyperkalemia, and pulmonary edema may require medical treatment with sodium bicarbonate, antihyperkalemic measures, and diuretics. Lack of improvement with fluid resuscitation, therapy-resistant hyperkalemia, metabolic acidosis, or fluid overload may necessitate artificial support in the form of dialysis or hemofiltration. However, oliguria during anesthesia may predict AKI, but the effect of a fluid load is highly variable. Striving toward a predefined urine output  target to prevent AKI is futile. Early recovery of AKI
AKI recovery can be classified into three stages 1–3 on the basis of the inverse of the AKI KDIGO serum creatinine criteria. Prognosis
Mortality
Mortality after AKI remains high. AKI has a death rate as high as 20%, which may reach up to 50% in the intensive care unit (ICU). Each year, around two million people die of AKI worldwide.AKI develops in 5% to 30% of patients who undergo cardiothoracic surgery, depending on the definition used for AKI.