Ebook Millers textbook (8/E): Part 6
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Ebook Millers textbook (8/E): Part 6
Chapter 100Postoperative Visual LossSTEVEN ROTHKey Points•Visual loss after anesthesia is a rare but devastating injury that appears more frequently a Ebook Millers textbook (8/E): Part 6after cardiac, spine, and orthopedic joint surgery.•Causes of perioperative visual loss include central or branch retinal artery occlusion (RAO), anterior and posterior ischemic optic neuropathy (ION), cortical blindness, and acute glaucoma. Transient visual loss may occur after transurethral resect Ebook Millers textbook (8/E): Part 6ion of the prostate. Retinal vascular occlusion in patients who receive nitrous oxide-containing gas mixtures after a vitrectomy procedure with vitreaEbook Millers textbook (8/E): Part 6
l gas bubble tamponade is caused by acute expansion of the gas bubble and increased intraocular pressure.•Signs and symptoms of visual loss in the posChapter 100Postoperative Visual LossSTEVEN ROTHKey Points•Visual loss after anesthesia is a rare but devastating injury that appears more frequently a Ebook Millers textbook (8/E): Part 6ility to perceive light or motion, complete or partial loss of visual fields, decreased visual acuity, or loss of pupil reactivity must be evaluated immediately by an ophthalmologist.•The most common cause of perioperative central and branch RAO is compression of the eye. During cardiac surgery, emb Ebook Millers textbook (8/E): Part 6oli may occlude the retinal arteries.•Patients who undergo prolonged operative procedures in the prone position with large blood losses are at frequenEbook Millers textbook (8/E): Part 6
t risk for development of ION. Other factors conferring a more frequent risk during spine surgery include male gender, obesity, the use of a Wilson frChapter 100Postoperative Visual LossSTEVEN ROTHKey Points•Visual loss after anesthesia is a rare but devastating injury that appears more frequently a Ebook Millers textbook (8/E): Part 6travascular fluid administration, and use of vasopressors in these patients. The potential risk for ION should be considered in the design of an anesthetic plan. Patients must be informed of the risk for visual loss accompanying lengthy surgical procedures with the patient positioned prone and with Ebook Millers textbook (8/E): Part 6anticipated large blood loss. Both anesthesia and surgery personnel, together, should develop a plan in conjunction with the surgeons by which informeEbook Millers textbook (8/E): Part 6
d consent for this complication may be facilitated.•Perioperative visual loss in the presence of focal neurologic signs or the loss of accommodation rChapter 100Postoperative Visual LossSTEVEN ROTHKey Points•Visual loss after anesthesia is a rare but devastating injury that appears more frequently a Ebook Millers textbook (8/E): Part 6VL) is a rare but unexpected and devastating complication, spine surgery, particularly when fusion is performed, is one of the most common procedures associated with POVL. Hence, a major emphasis of this chapter is on POVL associated with spine surgery The incidence, suspected risk factors, diagnosi Ebook Millers textbook (8/E): Part 6s, and treatment of eye injuries leading to visual loss in the perioperative period are discussed. The discussion is confined to visual loss that follEbook Millers textbook (8/E): Part 6
ows nonocular surgery because eye damage after ocular surgery is well described in the ophthalmology literature (see also Chapter 84). Injuries to theChapter 100Postoperative Visual LossSTEVEN ROTHKey Points•Visual loss after anesthesia is a rare but devastating injury that appears more frequently a Ebook Millers textbook (8/E): Part 6tudies and published surveys and case reports provide much of the current knowledge on postoperative visual loss. Two large retrospective studies showed that perioperative ischemic optic neuropathy (ION) is rare, occurring in approximately 1 in 60.000 to 1 in 125.000 anesthetic procedures in the ove Ebook Millers textbook (8/E): Part 6rall surgicalpopulation.1-2Spine and cardiac surgery are associated with a more frequent incidence of POVL than other operative procedures. Shen and aEbook Millers textbook (8/E): Part 6
ssociates' examined the POVL prevalence in the U.S. database. Nationwide Inpatient Sample (NIS). for the eight most commonly performed surgical3011301Chapter 100Postoperative Visual LossSTEVEN ROTHKey Points•Visual loss after anesthesia is a rare but devastating injury that appears more frequently a Ebook Millers textbook (8/E): Part 6ent were spine (3 09 per 10.000. 0.03%) and cardiac surgery <8.64 per 10.000. 0.086%). The yearly rates of POVL in the procedures studied by Shen and colleagues5 have been decreasing in the 10-yeai period from 1996 to 2005. Patil and colleagues* found an overall rate of 0.094% in spine surgery disch Ebook Millers textbook (8/E): Part 6arges in the NIS 4 In previous. smaller case series. Stevens and colleagues- found four ION cases in 3450 spine suigeries (0.1%). and two cases in 330Ebook Millers textbook (8/E): Part 6
0 patients after spine surgery were reported at another hospital <0.06%).6 Chang and Miller reviewed 14.102 spine surgery procedures in one hospital, Chapter 100Postoperative Visual LossSTEVEN ROTHKey Points•Visual loss after anesthesia is a rare but devastating injury that appears more frequently a Ebook Millers textbook (8/E): Part 6recent larger retrospective studies.’ 10Myers and associates11 conducted a retrospective casecontrol study of 28 patients with visual loss after spine surgery. The American Society of Anesthesiologists (ASA) Postoperative Visual Loss Registry reported on 93 cases of visual loss after spine surgery s Ebook Millers textbook (8/E): Part 6ubmitted anonymously to the ASA Closed Claims Study.12 Nuttall and associates’ performed a retrospective case-control study of cardiac suigery patientEbook Millers textbook (8/E): Part 6
s at the Mayo Clinic.® The most recent study was a retrospective, case-controlled study of factors involved in perioperative ION in spine surgery, a cChapter 100Postoperative Visual LossSTEVEN ROTHKey Points•Visual loss after anesthesia is a rare but devastating injury that appears more frequently a Ebook Millers textbook (8/E): Part 6NAL ISCHEMIA: BRANCH AND CENTRAL RETINAL ARTERY OCCLUSIONCentral retinal artery occlusion (CRAO) decreases the blood supply to the entire retina, whereas occlusion of a retinal arterial branch (BRAO) is a localized injury affecting only a portion of the retina. This injury IS usually unilateral. Fou Ebook Millers textbook (8/E): Part 6r causes can be distinguished: < 1 > external compression of the eye. (2) decreased arterial supply to the retina (embolism to the retinal arterial ciEbook Millers textbook (8/E): Part 6
rculation or decreased blood flow fiom a systemic cause). (3) impaired venous drainage of the retina, and (4) arterial thrombosis from a coagulation dChapter 100Postoperative Visual LossSTEVEN ROTHKey Points•Visual loss after anesthesia is a rare but devastating injury that appears more frequently a Ebook Millers textbook (8/E): Part 6g sufficient intraocular pressure HOP) to stop flow in the central retinal artery (see also Chapter 41). It most commonly occurs during spine surgery performed with the patient in the prone position. Pressure within the orbit also can be increased internally after retrobulbai hemorrhage, which is as Ebook Millers textbook (8/E): Part 6sociated with vascular injuries during sinus or nasal suigery.Although rare in most surgical procedures, emboli can directly impair blood flow in theEbook Millers textbook (8/E): Part 6
central retinal artery (CRA) Itself or a branch of it. Paradoxical embolism originating from the operative site and leaching the arterial circulation Chapter 100Postoperative Visual LossSTEVEN ROTHKey Points•Visual loss after anesthesia is a rare but devastating injury that appears more frequently a Ebook Millers textbook (8/E): Part 6mmon during open heart surgery.15 Hypotension itself seemsFigure 100 1. Funduscop« appearanceof retinal vascular occlusion. Note the pallor of the retina and the cherry-red spot, visible in the fovea near the center of the photograph. The ischemic retina loses its normal transparency, and because th Ebook Millers textbook (8/E): Part 6e fovea is thinner than the surrounding retina, the underlying choroid IS visible as a cherry-red spot. (From Ryơn S/ Retina, eci 2, St. Louis, cv MosEbook Millers textbook (8/E): Part 6
by, Ì 995 )to be a rare cause of retiual ischemia. The incidence of retinal ischemia after hypotensive anesthesia was only 3 cases in 27.930 hypotensiChapter 100Postoperative Visual LossSTEVEN ROTHKey Points•Visual loss after anesthesia is a rare but devastating injury that appears more frequently a Ebook Millers textbook (8/E): Part 6y patients positioned pione. 1OP increased and head-down position resulted in further increases. Changes were attenuated by head-up positioning.151’ The clinical significance of these changes are not clearCLINICAL FINDINGSPainless visual loss and abnoimal pupil reactivity occur. Funduscopic examinat Ebook Millers textbook (8/E): Part 6ion shows opacification or whitening of the ischemic retina, and narrowing of retinal arterioles may be visible - BRAO IS characterized by cholesterolEbook Millers textbook (8/E): Part 6
emboli (bright yellowish, glistening), calcific emboli (white, nonglistening), or migrant pale platelet fibrin emboli (dull, dirty white). A cherry-rChapter 100Postoperative Visual LossSTEVEN ROTHKey Points•Visual loss after anesthesia is a rare but devastating injury that appears more frequently a Ebook Millers textbook (8/E): Part 6earance from pallor in the ischemic, overlying retina makes visible the color of the intact, underlying choroidal circulation. However, this sign is not always present; thus, its absence does not rule out retiual artery occlusion (RAO). Differential diagnosis from other causes of visual loss IS pres Ebook Millers textbook (8/E): Part 6ented in Table 100-1.MECHANISMS OF RETINAL ISCHEMIAIncreased extracellular glutamate concentrations during retinal ischemia2- and attenuation of ischeEbook Millers textbook (8/E): Part 6
mic injury in vitro and in vivo by glutamate receptor antagonists22 support a role for excitotoxicity It is thought that anChapter 100:TABLE 100-1 DIFGọi ngay
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