Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0086543 (cataract)
 29,165 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We studied the effects of a single i.v. dose of dexmedetomidine, a highly selective and specific alpha 2 adrenoceptor agonist, on intraocular pressure (IOP), haemodynamic and sympathoadrenal responses to laryngoscopy and tracheal intubation, and on anaesthetic requirements in ophthalmic surgery. Thirty ASA I-II patients undergoing cataract surgery were allocated randomly to receive either dexmedetomidine 0.6 microgram kg-1 or saline placebo i.v. 10 min before induction of anaesthesia in a double-blind design. After dexmedetomidine there was a 34% (95% confidence interval (CI) 27-43%) reduction in IOP (P less than 0.001) and 62% (CI 57-68%) decrease in plasma noradrenaline concentrations (P less than 0.001). After intubation, maximum heart rate was 18% (CI 3-33%, P = 0.036) and the maximum IOP 27% (CI 11-43%, P = 0.005) less in the dexmedetomidine group compared with the patients treated with placebo. Within 10 min after intubation, maximum systolic and diastolic arterial pressures were also significantly (P = 0.013 and P = 0.020) smaller in the dexmedetomidine group. The induction dose of thiopentone was smaller (23% (CI 20-26%) P = 0.012), and the use of isoflurane or fentanyl supplements during anaesthesia was less frequent in the dexmedetomidine group. The patients premedicated with dexmedetomidine recovered faster from anaesthesia (P = 0.042). These results suggest that dexmedetomidine may be a useful anaesthetic adjunct in ophthalmic surgery.
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PMID:Dexmedetomidine reduces intraocular pressure, intubation responses and anaesthetic requirements in patients undergoing ophthalmic surgery. 2651 Jun 69

Benzodiazepines for sedation may decrease the PaO2, the arterial O2 saturation (SaO2), and the CO2 response more in the elderly than in the young. The purpose of this study was to assess changes in blood gases due to i.v. midazolam or sublingual flunitrazepam given as premedication in elderly patients for unilateral cataract surgery. METHODS. Fifty patients over 65 years of age with treated arterial hypertension and other co-existing diseases (ASA III-IV) were randomly assigned to have: (1) i.v. midazolam titrated until they became drowsy (17 patients; 2.85 +/- 0.84 mg [mean +/- SD]); (2) sublingual flunitrazepam (16 patients; 0.005 mg/kg); or (3) no sedation (17 patients; controls). On entering the operating theatre, the radial artery was cannulated and the first blood gas analysis was obtained. The premedication was then given. At 5, 10, 20, and 30 min after premedication, before and 10 min after retrobulbar block, before operation, 5 and 15 min after the beginning of the operation, 10 and 20 min after administration of 500 mg acetazolamide i.v. during the operation, and 10 and 20 min after the operation additional arterial blood samples were analysed (a total of 15 measuring points). Pulse oximetry, invasive blood pressure, and ECG were continuously monitored. All patients received oxygen 3 l/min during the operation by nasal cannula. Differences between the three groups were analysed by Student's t-test or U-test and a P value < 0.05 was considered significant. RESULTS. The patient demography, including duration of anaesthesia and operation, was similar in the three groups (Table 1). No significant differences were seen in heart rate, mean arterial pressure, PaO2, pulse-oximetric oxygen saturation (SpO2), base excess, or serum bicarbonate levels. The PaCO2 increased in patients after midazolam (P < 0.01) and flunitrazepam (P < 0.05) until the beginning of the operation compared with the control group (Fig. 3); 20 min after the operation there was still a significant difference between the midazolam group and the controls. SaO2 was significantly (P < 0.05) lower in the midazolam group 10 and 20 min after administration of premedication compared with the control group, but was within physiological limits (Fig. 5). Despite titration, 2 patients had severe respiratory insufficiency 3 min after midazolam: the SpO2 decreased below 85% and the paO2 below 55 mmHg. The paCO2 was higher (P < 0.05) in the midazolam group 10 min after acetazolamide compared with the controls. CONCLUSIONS. The results of the study show the potential hazards of i.v. midazolam in the elderly. If sedation is required for cataract surgery under local anaesthesia, we recommend sublingual flunitrazepam or the use of benzodiazepines with lower hypnogenic effects in the elderly. A thorough preoperative discussion of anaesthesia and the operation might be an adequate substitute for any premedication in high-risk patients; the best blood gas analysis results were obtained in the control group.
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PMID:[Premedication in retrobulbar anesthesia. A blood gas analysis comparison of sublingual flunitrazepam and intravenous midazolam]. 146 54

Administering intravenous sedation in conjunction with intraoperative monitoring to cataract surgery patients is a widely accepted technique. Numerous articles report local sedation techniques for cataract surgery that are, in essence, abbreviated general anesthetic techniques for insertion of the retrobulbar block (RBB). Because of variations in levels of consciousness, a number of complications have been encountered with this specific patient population, ie, movement upon insertion of the RBB, intraoperative patient movement, confusion, hypotension, respiratory depression, and respiratory arrest. In an attempt to meet the specific needs of this patient population, a study comparing propofol-fentanyl with midazolam-fentanyl was initiated. Seventy-five (ASA 1 to 3) patients were randomly assigned to two groups: propofol-fentanyl (P/F) or midazolam-fentanyl (M/F). The mean age of patients in the P/F group was 71.1 +/- 13 SD, and the mean age in the M/F group was 74.4 +/- 8.8 SD. All patients entered the operating room unpremedicated. Before the RBB, patients in both groups were given a single intravenous dose of 50 micrograms fentanyl. Propofol (mean dose, 24.7 mg) or midazolam (mean dose, 1.58 mg) was then titrated to slurred speech or nystagmus. Patients' responses to the RBB were evaluated and recorded by an objective observer. The amnestic properties of both agents were evaluated by patient questioning at 10 minutes and 24 hours. Levels of discomfort were evaluated on a scale of 1 to 5, with 1 being extremely uncomfortable and 5 being noticeable without pain. Respiratory depressant effects of both techniques was assessed via continuous pulse oximetry. Results were analyzed using the chi 2 test, rank t test, and SD.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Propofol-fentanyl versus midazolam-fentanyl: a comparative study of local sedation techniques for cataract surgery. 147 88

Cataract is the major cause of blindness worldwide and at present the only approved treatment in many countries including the UK and USA is surgical removal of the lens. In other countries various anti-cataract drugs are available without proof of their efficacy. Research is continuing into the possible benefits of several groups of drugs and some vitamins. The first to be studied were sorbitol-lowering agents (aldose reductase inhibitors) based on the sorbitol hypothesis for diabetic cataract. Sorbitol-lowering agents have distinct effects in vitro and many of them delay the development of cataract in galactose-fed rats. A few delay cataract in diabetic rats but none have been proved effective in clinical trials, although these continue. Aspirin, paracetamol (acetaminophen) and ibuprofen delay diabetic cataract in rats, and have been shown to delay other experimental cataracts. Case-control studies from 3 continents indicate that these drugs, or at least aspirin, protect against cataract. Results of studies on all 3 drugs indicate a benefit even at low doses. Population-based studies did not identify any protection against early lens opacities but tiny opacities that do not impair vision are not a problem. Bendazac protects lens proteins in vitro and delays cataractogenesis in x-irradiated rats. In humans, it reached the clinical trial stage but most trials have been small and with subjective criteria of opacification. One objectively monitored trial suffered from a high drop-out rate. Other preparations studied less extensively include vitamins, aminoguanidine to prevent protein cross-linking in diabetes and agents designed to boost glutathione levels. It is probable that some agents which may delay or prevent cataract will be proved effective soon, and in the end there may be different drugs to delay cataract in different high risk groups. This is what might be expected of a multifactorial disease, although compounds that intervene in the final common pathways to cataract could have a broad efficacy.
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PMID:Pharmacological treatment strategies in age-related cataracts. 150 43

The effects of i.m. alfentanil and midazolam on anxiety, sedation, hemodynamics, oxygen saturation and intraocular pressure were studied in 90 patients scheduled for outpatient cataract surgery with regional anesthesia. The study was randomized, double-blind, placebo-controlled, and performed on outpatients with ASA physical status I-III and mean age 67.7 +/- 11.7 years. Alfentanil (12.5 micrograms/kg) administered into the deltoid muscle had a marked anxiolytic and short sedative effect, and was associated with stable hemodynamics. Midazolam (20 micrograms/kg) administered similarly had a more prolonged anxiolytic and sedative effect, which impaired co-operation in some patients during surgery. The regional blockade was associated with a significant reduction of oxygen saturation (SpO2), regardless of the premedication used (P less than 0.05). A slight reduction of intraocular pressure (IOP) was found after premedication, but the change was not statistically significant. We conclude that i.m. alfentanil is well tolerated, and its anxiolytic and short sedative effects make it especially suitable as premedication for day-case cataract surgery.
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PMID:Premedication for outpatient cataract surgery: a comparative study of intramuscular alfentanil, midazolam and placebo. 151 42

Several studies comparing retrobulbar block (RB) and general anaesthesia (GA) for cataract surgery in the elderly have been published. Most of them were retrospective. Our prospective study was designed in order to determine the benefits or disadvantages using RB or GA. Arterial blood gases (ABG) and cardiovascular stability were explored in high-risk patients undergoing elective unilateral cataract extraction. METHODS. Forty patients over 65 years of age and with other co-existing diseases (ASA III-IV) were allocated randomly to receive either GA or RB. No premedication was given to either group of patients. On arrival in the anaesthetic room, a radial artery was cannulated for collection of blood samples and direct monitoring of the blood pressure. Pulse oximetry and ECG were continuously monitored in all patients, the end-expiratory CO2 (F(eexCO2)) only in the GA group. GA was induced with vecuronium 0.1 mg/kg and thiopentone 5 mg/kg; the lungs were ventilated with 100% oxygen. After intubation of the trachea controlled mechanical ventilation was continued with N2O/O2 (55:45) and enflurane 1%-2%. Only enflurane concentrations were varied to correct changes in mean arterial pressure (MAP) if these exceeded +/- 20%. Respiratory frequency and tidal volume were kept constant until completion of surgery. The patients were extubated when they were able to ventilate more than 5 1/min (pressure support 10 cmH2O; PEEP 5 cmH2O). After extubation no O2 was given. In the RB group neural block was undertaken with prilocaine 2% (3 ml) as a retrobulbar injection and prilocaine 1% (5 ml) to block the facial innervation of the orbicularis muscle (Van Lint, O'Brien). Oxygen 3 1/min was administered by nasal tube during the operation. Nine arterial samples for blood gas analysis were collected: (1) control; (2) before operation; (3) 5 min after beginning the operation; (4) 15 min after beginning the operation and before i.v. administration of 500 mg acetazolamide over 5 min; (5) after acetazolamide; (6 and 7) 10 and 20 min after acetazolamide; and (8 and 9) 15 and 30 min after operation (RB) or extubation (GA). RESULTS. The patient demography, including duration of anaesthesia and operation, was similar in both groups (Table 1). Four patients in the GA group (2 needed O2 after extubation because of hypoxaemia) and 2 in the RB group were excluded. No significant differences were seen in base excess (BE) and standard bicarbonate (SHCO3). Arterial O2 tension, arterial O2 saturation, and pulse-oximetric O2 saturation were higher in the RB group intra- and postoperatively (Figs. 1, 3, 4). Arterial CO2 tension (PaCO2) was significantly higher in the GA group during the pre- and postoperative period (Fig. 2), but not during the operation. The PaCO2- F(eexCO2) gradient ranged between 5 and 9 mmHg. Administration of acetazolamide did not influence this gradient by regressive analysis. The postoperative outcome of the patients was comparable in both groups. Nausea or vomiting did not occur. MAP was significantly higher in the RB group during the operation. No significant differences were seen in the pre- and postoperative period. Heart rate in the GA group was higher only after extubation, but was within physiological limits. DISCUSSION. Despite the differing results between the two groups, our study showed no important advantage related to either RB or GA. Changes in ABG, MAP, and heart rate during the investigation period were within physiological limits in elderly patients. Intravenous acetazolamide did not influence ABG in a significant manner. With regard to the preference of each patient, we recommend both RB and GA for cataract surgery in high-risk patients on the assumption of sufficient preoperative treatment of co-existing diseases. In conclusion, cardiovascular and ABG stability were maintained during both anaesthetic techniques.
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PMID:[General anesthesia vs. retrobulbar anesthesia in cataract surgery. A randomized comparison of patients at risk]. 152 60

The Early Treatment Diabetic Retinopathy Study, a randomized clinical trial supported by the National Eye Institute, was designed to assess the effect of photocoagulation and aspirin in 3711 patients with mild to severe nonproliferative or early proliferative diabetic retinopathy. Although the primary goal of the study was to evaluate the effect of photocoagulation and aspirin on diabetic retinopathy, the study also provided an opportunity to evaluate the effects of aspirin on the development of cataract. No evidence showed that aspirin use reduced the risk of development of cataract requiring extraction (4.1% vs 4.3% in patients assigned to aspirin or placebo treatment, respectively; Mantel-Cox P = .77; relative risk, 1.05; 99% confidence interval, 0.73 to 1.51). Aspirin use also did not reduce the risk of less extensive but visually significant lens opacities developing (29.6% vs 28.3%; Mantel-Cox P = .76; relative risk, 0.99; 99% confidence interval, 0.85 to 1.15). Early Treatment Diabetic Retinopathy Study results do not support the hypothesis that aspirin (at a dose of 650 mg/d) reduces the risk of cataract development in this diabetic population.
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PMID:Aspirin effects on the development of cataracts in patients with diabetes mellitus. Early treatment diabetic retinopathy study report 16. 154 49

Fifty patients more than 70 years old, ASA I and II, NYHA I and II, were anaesthetized by propofol for cataract or retinal detachment surgery. Induction was carried out by a propofol slow injection (0.5-1 mg.s-1) until loss eyelash reflex (mean dose 0.728 mg.kg-1) and completed by fentanyl 2 micrograms.kg-1 and vecuronium 0.08 mg.kg-1. After intubation, anaesthesia was maintained with nitrous oxide and continued infusion of propofol (mean dose 4.48 mg.kg-1.h-1) according to haemodynamic parameters. These were noted repeatedly and statistically analyzed. No significative differences were observed with younger patients undergoing identical surgical procedures. Haemodynamic effects were the same during cataract or retinal detachment surgery and in hypertensive treated patients vs non hypertensive ones. Recovery was as fast and good as in younger patients. It should be emphasized that propofol doses must be reduced in elderly patients so as to preserve a satisfactory haemodynamic stability. Reasons for increased sensitivity to propofol in elderly patients are briefly discussed.
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PMID:[Propofol anesthesia for ophthalmologic surgery in the elderly]. 159 26

Ultraviolet (UV) filter photography with the Topcon SL-45 Scheimpflug camera has provided valuable informations about age-related and cataract-type-dependent changes in the spectral properties of the human lens. The present study deals with the same phenomenon in normal lenses of the Brown-Norway rat and in those with true diabetic and naphthalene cataracts. The lenses of all animals of the 3 groups were photographed at the middle and final examination of a 6-week experiment on Kodak Tri-X-pan ASA 400 black-and-white film, using visible light (xenon flash) and UV-filtered light (320-390 nm transmission) from the same light source for recording. The results clearly demonstrate that both cataract models exhibit characteristic fluorescence properties, different from each other and from normal rat lenses. The naphthalene cataract shows the most drastic increase in fluorescence in the cortex, compared to the increase in scattering with visible light. The versatility of the method in preclinical research and the versatility of the cataract models open new aspects of drug-related research in drug toxicity studies.
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PMID:Ultraviolet filter photography to demonstrate the fluorescence of animal lenses with different cataract models. 214 14

Cataract, the major cause of blindness world-wide, may be caused partly by modification of lens proteins by carbamylation and non-enzymic glycosylation (glycation) in some patients. Aspirin has been found to protect against these modifications and to prevent cyanate-induced opacification occurring in whole rate lenses. Ibuprofen is an aspirin-like anti-inflammatory drug which appeared as a protective factor against cataract in an Oxford case-control study. The binding of cyanate, galactose and glucose 6-phosphate to lens proteins, and the effect of ibuprofen on this reaction was investigated, as was cyanate-induced opacification in whole rat lenses. Labelled metabolite was incubated with bovine lens homogenate in the presence and absence of ibuprofen, and the incorporation of label into the lens homogenate was followed. Simultaneous and preincubation experiments were performed. Intact rat lenses were incubated in culture medium with and without cyanate and ibuprofen. The phase separation temperature was noted as the temperature at which opacity first appeared on cooling. Cyanate, galactose and glucose 6-phosphate bind progressively to lens proteins. Simultaneous incubation with ibuprofen reduces cyanate and galactose binding but not glucose 6-phosphate. Ibuprofen protects against opacities due to cyanate-induced phase separation. Ibuprofen has protected against cataract in the models of cataractogenesis in this study. It appears to have a different mechanism of action from that of aspirin. These studies provide some support for the idea, based on epidemiological findings, that ibuprofen might be a useful anti-cataract drug.
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PMID:Ibuprofen, a putative anti-cataract drug, protects the lens against cyanate and galactose. 231 79


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