Intraocular pressure, postoperative

Succinylcholine Agonist at nicotinic acetylcholine (ACh) receptors, especially at neuromuscular junctions depolarizes may stimulate ganglionic nicotinic ACh and cardiac muscarinic ACh receptors Initial depolarization causes transient contractions, followed by prolonged flaccid paralysis depolarization is then followed by repolarization that is also accompanied by paralysis Placement of tracheal tube at start of anesthetic procedure t rarely, control of muscle contractions in status epilepticus Rapid metabolism by plasma cholinesterase normal duration, 5 min Toxicities Arrhythmias hyperkalemia transient increased intraabdominal, intraocular pressure postoperative muscle pain... 

Fig. 109. Remained viscoelastic substance behind the lOL after incomplete removal of the viscoelastic may cause an increase in intraocular pressure postoperatively, a deviation from the target refraction or even a change in refraction...

Succinylcholine produces muscle fasciculation, which may result in myoglobinuria and postoperative muscle pain. The amount produced depends on the level of physical fitness. Succinylcholine causes contractions of extraocular muscles, posing the danger of transient elevated intraocular pressure. Succinylcholine may produce hyperkalemia in patients with large masses of traumatized or denervated muscle (e.g., spinal cord injury). Denervated muscle is especially sensitive to depolarizing drugs because of the increased number of AChRs on the sarcolemma (denervation supersensitivity). Succinylcholine also causes prolonged contraction of the diseased muscles of patients with myotonia or amyotrophic lateral sclerosis. 

Oxybutynin Nonselective muscarinic antagonist Reduces detrusor smooth muscle tone, spasms Urge incontinence postoperative spasms Oral, IV, patch formulations Toxicity Tachycardia, constipation, increased intraocular pressure, xerostomia Patch Pruritus Interactions With other antimuscarinics... 

Primary eye care providers may collaborate with ophthalmic surgeons to comanage the cataract patient. This method of eye care delivery provides quality care for the patient in convenient familiar surroundings. In addition, it is efficient and cost-effective. The goals of the comanagement team during postoperative care are those of everyday optometric practice to educate and reassure the patient, to prevent infection, to control inflammation, to maintain desired intraocular pressure (lOP), to manage complications if they arise, to control pain, and to optimize vision. 

The major adverse effect associated with the use of viscoelastic substances, such as hyaluronate sodium, is a transient rise in intraocular pressure in the immediate postoperative period, attributed to its viscoelastic nature, resulting in coating and plugging of the trabecular mesh-work. For this reason, it is advisable to dilute hyaluronate sodium at the end of the surgical procedure with a balanced salt solution. Chondroitin sulfate is relatively less likely to precipitate such extreme rises in intraocular pressure because it is cleared rapidly from the trabecular meshwork. However, with any technique or chemical used in surgery there is always the potential for an unexpected adverse effect, and the risks of Viscoat include subepithelial calcium deposition and keratopathy (3). 

Jonas et al. (47) performed an uncontrolled study of intravitreal triamcinolone acetonide to treat exudative AMD. Of 71 treated eyes, 68 had predominantly or totally occult CNV, as determined by fluorescein angiography. With a mean follow-up of seven months, the visual acuity increased from a preinjection mean of 0.16 to a maximum of 0.23 (P < 0.001). The maximal visual acuity was attained at 1-3 months postinjection. However, there was no significant visual acuity difference by 7.5 months, when compared with pretreatment visual acuity. The average intraocular pressure (IOP) increased from a baseline of 15.1 to 23.0 mmHg. There were no significant postoperative complications such as endophthalmitis and retinal detachment. 

V 1 1 IM/IV. Diffuses away from endplate, hydrolyzed by plasma pseudocholinesterase and acetylcholinesterase. T intraocular pressure (contraindicated open eye wounds) and gastric pressure (caution reflux during intubation), dysrhythmias. Postoperative muscle pain (myoglobin release and hyperkalemia). May trigger malignant hyperthermia. 1. Fasciculations in chest and abdomen 2. Neck, arms, legs 3. Facial, phaiynx, larynx 4. Respiratory muscles Effects not reversed by acetylcholinesterase inhibitors. Effects are poorly reversed by electrical stimulation. 

Osmotics are preoperative and postoperative medications used to reduce intraocular pressure by decreasing vitreous humor volume. They are also used in the emergency treatment of closed-angle glaucoma. Patients who are administered osmotics can experience headache, nausea, vomiting, and diarrhea. Elderly patients can become disoriented. 

The use of intraocular sodium hyaluronan is complicated by a postoperative rise in intraocular pressure. This rise in intraocular pressure is thought to stem from clogging of the trabecular meshwork by the large molecules of hyaluronan. Hein et al. demonstrated the potential usefulness of hyaiuronidase and documented the lack of harmful side effects histopathologically (106). Knepper et al. compared two enzymes, testicular hyaiuronidase and Streptomyces hyaiuronidase, that degrade hyaluronan (107), and concluded that Streptomyces hyaiuronidase is more effective than testicular hyaiuronidase for decreasing aqueous outflow resistance and that hyaluronan is an important glycosaminoglycan contributor to aqueous outflow resistance in the normal rabbit eye. 

Reduction of postoperative intraocular pressure after penetrating keratoplasty ... 

A combination of HA-Na and the nonsteroidal antiinflarrunatory drug Timolol was used for managing early postoperative intraocular pressure... 

Burke, S., Sugar, J. and Farber, M. D., Comparison of the effects of two viscoelastic agents, Healon and Viscoat, on postoperative intraocular pressure after penetrating keratoplasty, Ophthal. Surg., 21, 821,1990. 

Anmarkmd, N., Bergaust, B. and Bulle, T., The effect of Healon and Timolol on early postop>erative intraocular pressure after extracapsular cataract extraction with implantation of posterior chamber lens, Acta. Ophthalmol., 70,96,1992. Punzi, L., Schiavon, F., Ramonda, R., Malatesta, V. and Bambari, P., Intra-articular hyaliuxrnic acid in the treatment of inflammatory and non-inflamma-tory knee effusions, Curr. Ther. Res., 43, 643,1988. 

Early postoperative increases in intraocular pressure were seen to differ, however, between various hyaluronic acid-containing viscoelastic substances in ECCE procedures (Henry 8c Olander, 1996). In a prospective, blind, randomized study. Fry and Yee (1993) found a significantly raised intraocular pressure 8 hours following ECCE with application of Healon GV (higher concentration as well as molecular weight) with respect to Healon . A similar difference was not manifest with phacoemulsification (Kohnen et al., 1996). 

Glasser and co-workers regarded the highest possible removal of viscoelastic substance from the eye as a prophylactic measure against raised postoperative intraocular pressure (1986 Fig. 58). 

As treatment for postoperative pressure peaks, acetazolamide (Lewen 8c Insler, 1985), as well as diverse beta-blockers (Duperre et al., 1994 Fry, 1992 Kanellopoulos et al., 1997a and b Percival, 1982 Pfeiffer, 1993) and parasypathomimetics (e.g., pilocarpine) have been shown to lower intraocular pressure to varying extents. 

Fig. 100. Glaukomflecken at the anterior lens capsule due to high postoperative intraocular pressure after perforating keratoplasty (1st day postoperatively)...

In a trial performed by Wedrich Menapace (1992), the removal of viscoelastic from behind the lOL lowered the incidence of early postop intraocular pressure peaks (Fig. 109). To mobilize OVD from behind the IOL,the irrigation/aspiration handle is generally lightly pressed onto the lOL optic. Moving the handle behind the lOL directly should be avoided so as not to aspirate the posterior capsule which would increase the danger of capsular damage (Wesendahl et al., 1994). 

Anmarkrud N, Bergaust B, Bulie T. The effect of Healon and timolol on early postoperative intraocular pressure after extracapsular cataract extraction with implantation of a posterior chamber lens. Acta Ophthalmol (Copenh) 1992 70 96-100... 

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