Causes of blindness in the adult population of the Republic of Ireland.

BACKGROUND/AIM: Blindness in the developed countries affects 3.5 million people. This study was conducted on the causes of blindness in the Republic of Ireland based on the register of the National Council for the Blind of Ireland. The aim was to determine the prevalence of potentially avoidable blindness and to identify its causes. METHOD: Criteria for registration as blind are in Ireland: best corrected visual acuity of 6/60 (0.1) or less in the better eye or a visual field restricted to 20 degrees or less. Data on 5002 adults 16 years an older registered as blind were analysed. The causes of blindness are classified in 17 diagnostic categories. RESULTS: The leading causes of blindness are macular degeneration and glaucoma, each accounting for 16% (812 and 795). Cataract accounted for 11% (561), a third of these had an associated cause of blindness and one tenth had a cognitive deficit. Diabetic retinopathy ranked as the 11th cause of blindness and accounted for 3% (147). More than half of the patients were 65 years and older. CONCLUSION: 25% of blindness was potentially avoidable. The treatable causes were glaucoma and diabetic retinopathy in the working population and glaucoma and cataract over 65 years of age. Glaucoma is the most important, which raises the question of a screening programme. The prevalence of blindness of 3% due to diabetic retinopathy is lower than in most other series.

Temperature corrected thrombelastography in hypothermic patients.

Thrombelastograms and other coagulation studies are performed at 37 degrees C, regardless of the patient's body temperature. This prospective study of 45 patients undergoing orthotopic liver transplantation was conducted to evaluate the effect on the thrombelastogram performed at the patient's actual body temperature compared with a control thrombelastogram heated in the standard fashion to 37 degrees C. Thrombelastograms were obtained after the induction of anesthesia and at various times throughout the operation when clinically indicated. A freshly drawn sample of the patient's blood was divided into two aliquots and run simultaneously on two thrombelastographs; one thrombelastograph was modified with a thermostat to perform the test at the patient's body temperature and the other was unmodified to serve as a control. The temperature of the patients in this study ranged from 36.9 degrees C to 32 degrees C. The variables of the thrombelastogram measured were: r (reaction time in minutes), r + K (coagulation time in minutes), alpha (coagulation rate in degrees), and MA (maximum amplitude in millimeters). Whenever the patient's body temperature was less than 37 degrees C, statistically significant prolongation of the reaction time, coagulation time, and decrease in the clot formation rate occurred compared with control variables at 37 degrees C. Overall means were as follows: r for control, 8.24 +/- 0.28 min; r for temperature corrected, 9.32 +/- 0.27 min; r + K for control, 15.4 +/- 0.65 min; r + K for temperature corrected, 17.5 +/- 0.81 min; and alpha for control, 39.8 +/- 1.22 degrees; alpha for temperature corrected, 37.7 +/- 1.23 degrees.(ABSTRACT TRUNCATED AT 250 WORDS)

Duration of vecuronium-induced neuromuscular block as a predictor of liver allograft dysfunction.

The major causes of liver graft failure are acute rejection, technical failure, and primary nonfunction (PNF). This study was undertaken to determine whether delayed return of neuromuscular function correlates with allograft primary dysfunction in humans given vecuronium. Twenty-two adult patients undergoing orthotopic liver transplantation were given an initial dose of vecuronium, 0.1 mg/kg intravenously (i.v.). All patients recovered from vecuronium-induced neuromuscular block prior to explantation. No additional neuromuscular blocker was given until the liver graft was implanted and reperfused. Fifteen minutes after reperfusion another 0.1 mg/kg vecuronium was given IV and recovery time from attaining complete neuromuscular block to return of the fourth twitch of a train-of-four was recorded. Patients were divided into three groups according to postoperative liver function. Group I consisted of 17 patients with immediate normal liver graft function. Group II consisted of four patients with primary dysfunction (PDF) [peak aspartate aminotransferase (AST) and alanine aminotransferase (ALT) > 2000 U/L, prothrombin time > 16 s, and poor quality and quantity of bile within 3 days postoperatively] which eventually recovered normal function. Group III consisted of one patient with PNF (uncorrectable coagulopathy, severe metabolic acidosis, rising AST and ALT, and minimal or no bile output), whose graft never recovered. Recovery time in Groups II and III was prolonged compared to Group I (P < 0.05). Recovery time in Group III was prolonged compared to Group II (P < 0.05). A test based on these results using a recovery time of > 135 min as a predictor of PDF has a sensitivity and specificity of 80% and 76%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood transfusion in orthotopic liver transplantation: six-year experience.

Patients undergoing orthotopic liver transplantation (OLT) are susceptible to massive blood loss and require transfusion. Possible reasons for increased transfusion demands include platelet abnormalities, thrombocytopenia secondary to hypersplenism, clotting factor deficiencies, fibrinolysis, increased surgical blood loss associated with portal hypertension and previous surgical procedures, and hypothermia. The purpose of this study was to review trends in blood product usage during our first 6 years of experience performing OLT.

Perioperative hemodynamic heterogeneity of brain dead organ donors.

Brain death is accompanied by a loss of homeostatic mechanisms leading to physiologic changes which have been shown to be detrimental to donor organs prior to procurement. The management of the brain dead organ donor (BDOD) is frequently left to transplant coordinators, often registered nurses, who follow standardized protocols for that management. The use of a standardized protocol assumes that these donors display homogeneity. To investigate this assumption, the anesthesiology fellows and faculty involved in multiorgan transplantation at the Baylor University Medical Center/UTSWMC conducted a study into the perioperative hemodynamics of the BDOD.

Effect of intraoperative low-dose dopamine on renal function in liver transplant recipients.

Patients undergoing orthotopic liver transplantation frequently receive dopamine infusions to preserve renal function. To test the benefit of such infusions on renal function, 48 nonanuric patients presenting for OLT were entered into a randomized double-blind protocol. After exclusion of 1 patient for intraoperative nephrectomy, 22 patients received dopamine at a rate of 3 micrograms.kg-1.min-1 during surgery and the first postoperative 48 h, and a control group of 25 patients received saline. Venovenous bypass was used in 45 of 47 patients. During the hepatic vascular anastomoses, the donor liver was flushed with cold saline. In 7 patients, the flush contained mannitol (50 g) as part of a surgical protocol to investigate its role as a potential free radical scavenger. Initially, it appeared that there was an increase in urine output during the neohepatic phase in those patients receiving dopamine versus controls (4.20 +/- 3.3 vs 2.10 +/- 1.3 ml.kg-1.h-1, respectively). Upon further statistical analysis, this increase was associated with inclusion of mannitol in the liver flush of 5 patients in the dopamine group. After excluding all patients receiving flush containing mannitol, there was no significant difference in urine output during the neohepatic phase between the dopamine group and controls (2.94 +/- 0.45 and 2.10 +/- 0.28 ml.kg-1.h-1, respectively). The glomerular filtration rates at 1 month after surgery were similar and decreased approximately 40% in each group. Although a beneficial effect of dopamine in all situations cannot be ruled out the authors conclude that routine perioperative use of dopamine is of little value in nonanuric patients presenting for orthotopic liver transplantation.

Perioperative renal function in patients undergoing orthotopic liver transplantation. A randomized trial of the effects of verapamil.

Patients who undergo orthotopic liver transplantation often experience a significant drop in GFR postoperatively. Postulated mechanisms include intraoperative hemodynamic changes, suboptimal renal perfusion during the anhepatic stage, and cyclosporine administration. We undertook a prospective double-blind study to investigate these factors, as well as to determine the protective effects of verapamil on perioperative renal function. Twenty-five patients with normal renal function undergoing OLT received either placebo (n = 13) or verapamil (n = 12) intraoperatively and for six weeks post-OLT. No CsA was administered until after reperfusion of the graft liver, and venovenous bypass (VVB) was utilized in all cases. Patients completing six weeks of the study experienced 61% and 48% decreases in GFR within the placebo and verapamil groups respectively. A significant decrease in GFR occurred in the placebo group between one and six weeks post-OLT, and a significant drop in GFR occurred in the verapamil group by one week post-OLT. Differences between the groups were not significant, however. Systemic, renal, and hepatic hemodynamics were similar at all times between groups, and renal hemodynamics and urine output were unchanged during VVB. We conclude that (1) perioperative factors do not contribute to renal dysfunction post-OLT when VVB is used; (2) VVB preserves renal hemodynamics during the anhepatic phase; (3) CsA is the most likely causative agent for post-OLT renal dysfunction; and (4) intraoperative verapamil serves no protective role, as administered in this study.

Is tracheostomy warranted in the burn patient? Indications and complications.

Considerable controversy exists as to whether a tracheostomy (TT) is ever indicated in burn patients. Eighty-eight tracheostomies were performed over a 48-month period. An inhalation injury was present in 59.6% of the patients, and 96% had preceding endotracheal intubation (ET). The mean duration of ET was 14 days. Seven percent, 17% and 58% of the TTs were performed within the 1st, 8th, and 14th postburn day, respectively. The indications for TT were: emergency airway access, 7%; complications secondary to ET, 8%; pulmonary sepsis, 75%; pulmonary failure, 10%. The mean duration of TT was 33 days (range: 1-209). Major complications associated with TT included: tracheomalacia, tracheostenosis, tracheoinnominate artery and tracheoesophageal fistulae, and posttracheostomy dysphagia. The decision to perform a TT or to continue with ET should not be predicated on an arbitrary number of days, but must be individualized and based on the clinical condition of the patient. The complications associated with a TT are related to previous ET and to the underlying pulmonary pathology necessitating ventilatory support.