More than 26 million Americans suffer with cataracts, and with 3.6 million cataract extractions performed annually in the United States, it is the most common surgical procedure. The integrity of the delicate structures of the eye that mediate vision is dependent on the intraocular pressure (IOP). Yet, IOP acts to compress the vessels within the globe—akin to a Starling resistor—and is a key component that determines the ocular perfusion pressure, defined as the difference between arterial pressure and IOP. The retina is one of the most metabolically active tissues in the body, and its functional integrity is dependent on an adequate blood supply, with retinal function linearly related to the ocular perfusion pressure. Retinal cell death has been demonstrated at low perfusion pressures (below 50 mm Hg). Modern ophthalmic surgery involves globe irrigation, manipulation, and instrumentation, resulting in dynamic pressure fluxes within the eye. Marked elevations of IOP (up to 4–5 times the normal value) with consequent borderline retinal and optic disk perfusion pressures occur for prolonged periods during many ophthalmic procedures. General surgeries, including laparoscopic, spinal, and cardiac procedures, especially, with their demand for steep Trendelenburg or prolonged prone positioning and/or hypotensive anesthesia, can induce IOP changes and ocular perfusion imbalance. These rapid fluctuations in IOP, and so in perfusion, play a role in the pathogenesis of the visual field defects and associated ocular morbidity that frequently complicate otherwise uneventful surgeries. The exact etiology of such outcomes is multifactorial, but ocular hypoperfusion plays a significant and frequently avoidable role. Those with preexisting compromised ocular blood flow are especially vulnerable to intraoperative ischemia, including those with hypertension, diabetes, atherosclerosis, or glaucoma. However, overly aggressive management of arterial pressure and IOP may not be possible given a patient's comorbidity status, and it potentially exposes the patient to risk of catastrophic choroidal hemorrhage. Anesthetic management significantly influences the pressure changes in the eye throughout the perioperative period. Strategies to safeguard retinal perfusion, reduce the ischemic risk, and minimize the potential for expulsive bleeding must be central to the anesthetic techniques selected. This review outlines: important physiological principles; ophthalmic and general procedures most likely to develop damaging IOP levels and their causative factors; the effect of anesthetic agents and techniques on IOP; recent scientific evidence highlighting the significance of perfusion changes during surgery; and key aspects of postoperative visual loss and management approaches for high-risk patients presenting for surgery.
https://ift.tt/2F21gep
Αρχειοθήκη ιστολογίου
-
►
2020
(289)
- ► Φεβρουαρίου (28)
-
►
2019
(9071)
- ► Δεκεμβρίου (19)
- ► Σεπτεμβρίου (54)
- ► Φεβρουαρίου (3642)
- ► Ιανουαρίου (3200)
-
▼
2018
(39872)
- ► Δεκεμβρίου (3318)
- ► Σεπτεμβρίου (3683)
-
▼
Απριλίου
(3319)
-
▼
Απρ 21
(42)
- Meat allergy and allergens
- Clinical Thyroidology®for the Public – Highlighted...
- Cytokines regulating lymphangiogenesis
- Development of next generation hemagglutinin-based...
- Overcoming wound complications in head and neck sa...
- Dermatology Subspecialty Clinic for Patients with ...
- Vitamin D Status in Scarring and Non-Scarring Alop...
- Analysis of Spin in the Reporting of Studies of To...
- Appropriate Use Criteria in Dermatopathology: Init...
- National Skin Cancer Expenditure Analysis in the U...
- Astroblastoma – a rare and challenging tumor: a ca...
- The Potential Public Health Impact of Herpes Zoste...
- Pure red cell aplasia and HIV infection: what to s...
- Corpus callosum demyelination associated with acqu...
- MonoMac syndrome with associated neurological defi...
- Periurethral abscess drained by iatrogenic urethra...
- Cluster of exertional rhabdomyolysis in three youn...
- Risperidone-associated sinus tachycardia potentiat...
- Xp11 translocation renal cell carcinoma paraneopla...
- JAMA Otolaryngology-Head & Neck Surgery.
- Pneumocystis jiroveci pneumonia in a patient takin...
- Rare case of otomastoiditis due to Coxiella burnet...
- SLIT’s Prevention of the Allergic March
- SLIT’s Prevention of the Allergic March
- Horizontal antimicrobial resistance transfer drive...
- Parental Bereavement in Young Children Living in S...
- Increased auditory cortex neural response amplitud...
- Inhibition processes are dissociable and lateraliz...
- Materialities
- Discovery in Medicine
- Military contractors and the money markets, 1700-15
- Correction to ‘Magnetic targeting of Microbubbles ...
- On the Feasibility of Using Current Data Centre In...
- State education, crisis and austerity : an histori...
- Epilogue: Exchanges: Time to Face the Strange?
- Predicting Severity of Acute Pain After Cesarean D...
- A Pain in the Abs: Predicting Post-Cesarean Analgesia
- Physiology and Role of Intraocular Pressure in Con...
- The Eyes Have It: Factors that Influence Intraocul...
- Patient Harm in Cataract Surgery: A Series of Adve...
- Preventing Adverse Events in Cataract Surgery: Rec...
- Acute Management of Bell’s Palsy
-
▼
Απρ 21
(42)
- ► Φεβρουαρίου (2693)
- ► Ιανουαρίου (3198)
-
►
2017
(41099)
- ► Δεκεμβρίου (3127)
- ► Σεπτεμβρίου (2173)
-
►
2016
(13807)
- ► Δεκεμβρίου (700)
- ► Σεπτεμβρίου (600)
- ► Φεβρουαρίου (1350)
- ► Ιανουαρίου (1400)
-
►
2015
(1500)
- ► Δεκεμβρίου (1450)
Ετικέτες
Εγγραφή σε:
Σχόλια ανάρτησης (Atom)
Δεν υπάρχουν σχόλια:
Δημοσίευση σχολίου