Evaluación de lente intraocular tórico AcrySof en corrección deastigmatismo concomitante a catarata en el Hospital Carlos VanBuren, Valparaíso / Evaluation of AcrySof intraocular toric lens in astigmatism correction concomitant to cataract in Hospital Carlos Van Buren, Valparaíso

INTRODUCCIÓN: Las cataratas son la principal causa de ceguera evitable, y su prevalencia aumenta en adultos mayores. Existe un porcentaje considerable de astigmatismo concomitante a cataratas, por lo que corregir ambas patologías en un mismo procedimiento quirúrgico resulta interesante para aumentar la agudeza visual postoperatoria. OBJETIVO: Evaluar la efectividad de la implantación de lentes intraoculares tóricos AcrySof en la corrección de astigmatismo concomitante a cataratas. MATERIALY MÉTODO: Estudio retrospectivo de grupo único cuya muestra son todos los pacientes que presentaban cataratas y astigmatismo corneal, con agudeza visual igual o menor a 0,5 (logMAR) operados mediante facoemulsificación con implante de lentes intraoculares tóricos AcrySof, en el Servicio de Oftalmología del Hospital Carlos Van Buren, entre enero del 2009 y septiembre del 2010, que cumplieran con los criterios de inclusión. Se obtuvo una muestra de 87 ojos de 77 pacientes, a los que se les midieron los parámetros agudeza visual, queratometría y refracción subjetiva preoperatoria y postoperatoria. Los pacientes fueron controlados los días 1, 7 y 30 del postoperatorio. RESULTADOS:El 61,33 por ciento y el 79,31 por ciento de los ojos intervenidos resultaron obtener una agudeza visual sin corrección y con corrección, respectivamente, mayor o igual a 20/40. La mediana del cilindro de la refracción subjetiva disminuyó significativamente después de la cirugía. DISCUSIÓN: La implantación de lentes intraoculares tóricos AcrySof durante la cirugía de facoemulsificación, para la corrección de cataratas, resultó ser un método efectivo para la corrección del astigmatismo concomitante.

INTRODUCTION: Cataracts are the main cause of preventable blindness, and its prevalence increases in older adults. There is a considerable percentage of astigmatism concomitant with cataracts, for this reason correct both conditions in a single surgical procedure is of interest to increase visual acuity postoperatively. OBJECTIVE: To evaluate the effectiveness of AcrySof toric intraocular lense implantation for cataract correction with concomitant astigmatism. MATERIAL AND METHOD: Retrospective study of single group, whose sample was all patients with cataract and corneal astigmatism with visual acuity equal or less than 0.5 (logMAR) operated by phacoemulsification with AcrySof toric IOL implantation, in the Ophthalmology Department of the Hospital Carlos Van Buren, between January 2009 and September 2010, who met the inclusion criteria. From all this resulted 87 eyes of 77 patients, measured visual acuity, keratometry and subjective refraction before and after surgery. RESULTS: Patients were evaluated on days 1, 7 and 30 of postoperatory. 61.33 percent and 79.31 percent of the operated eyes obtained an uncorrected and corrected visual acuity, respectively, greater or equal to 20/40. The median subjective refraction cylinder decreased significantly after surgery. DISCUSSION: AcrySof toric intraocular lense implantation during phacoemulsification surgery for cataract correction proved an effective method for correction of concomitant astigmatism.

Fluid responsiveness and right ventricular function in cardiac surgical patients. A multicenter study.

INTRODUCTION: We investigated fluid responsiveness in a population of patients undergoing coronary artery revascularization, with respect to their right ventricular ejection fraction. MATERIALS AND METHODS: This was a multicenter trial involving 11 cardiac surgical Institutions and 65 patients undergoing elective coronary artery revascularization. Hemodynamic parameters were measured before and after volume expansion using a modified pulmonary artery catheter and transesophageal echocardiographic monitoring. Patients demonstrating an increase of stroke volume >20% after volume expansion were considered as responders. Volume expansion with 7 ml/kg of plasma expander was performed when required on a clinical basis. RESULTS: In the overall population, only the change in aortic blood velocity (cut-off 13%) was a predictor of fluid responsiveness. In patients with a reduced (<0.3) right ventricular ejection fraction only the value of mean pulmonary arterial pressure was predictive of fluid responsiveness (cut-off 18 mmHg). Patients with right ventricular ejection fraction ≥0.3 demonstrated three predictors: changes in aortic blood velocity (cut-off 15%), right ventricular end diastolic volume index (cut-off 80 ml/m(2)), and left ventricular end diastolic area index (cut-off 9 cm(2)/m(2)). CONCLUSIONS: When right ventricular systolic function is depressed, the right ventricle inability to fill the left chambers results in a lack of the left-sided responsiveness predictors. When the right ventricular systolic function is preserved, all the classical fluid responsiveness predictors are confirmed. Right ventricular function is therefore to be always considered when addressing the problem of fluid responsiveness.

Outbreak of acute renal failure due to cefodizime-vancomycin association in a heart surgery unit.

OBJECTIVE: To describe an outbreak of acute renal failure (ARF) occurring in a group of patients undergoing open-heart surgery, simultaneously to a change in perioperative antibiotic prophylaxis. DESIGN: Case series. SETTING: A nine-bed heart surgery intensive care unit, serving a 1,300-bed University teaching hospital. PATIENTS: Thirty-two patients undergoing open-heart surgery during an 11-day period, when the preoperative surgical prophylaxis protocol had been changed from the usual antibiotic association of ceftriaxone + vancomycin to cefodizime + vancomycin. RESULTS: ARF occurred in 16 of the 32 (50%) patients exposed to the new antibiotic prophylaxis regimen; seven patients had oliguric ARF, and nine patients had an increase in serum creatinine (SCr) levels >50% over 24-48 h. In the seven patients with oliguric ARF, SCr increased from a median preoperative level of 88 micromol/l (80-115 micromol/l) to a peak value of 725 micromol/l (521-857 micromol/l) in 5 days (4-6). Eight patients out of the sixteen with ARF (50%) were diabetics, as opposed to none of the 16 patients not experiencing ARF. Renal biopsy (three patients) showed tubular dilation and necrosis, interstitial edema, and lymphomononuclear infiltrate of moderate degree. Only one patient required hemodialysis, and all recovered renal function. No other cases of unexplained ARF occurred in the unit after the original prophylaxis protocol was resumed. CONCLUSION: The simultaneous infusion of cefodizime and vancomycin may involve a high risk of substantial renal function derangement, especially in diabetics.

Detection of expiratory flow limitation during mechanical ventilation.

Two new methods, application of negative pressure at the airway opening during expiration (NEP) and reduction of flow resistance by bypassing the expiratory line of the ventilator by exhaling into the atmosphere (ATM), were used to detect expiratory flow limitation in 12 semirecumbent (45 degree) mechanically ventilated patients, seven with chronic airway obstruction (CAO). An increase of expiratory flow with NEP or ATM, relative to the preceding control breath, was taken as indicating absence of expiratory flow limitation. By contrast, the portion of the tidal expiration over which there was no change in flow with NEP or ATM was considered as flow-limited. With NEP, nine patients exhibited flow limitation, six (all with CAO) were flow-limited over most of the tidal expiration (> 70% VT), and three at < 60% VT. Although the results with NEP and ATM were in general in good agreement, in the three non-flow-limited patients the ATM method gave erroneous results. Six patients were also studied supine, including two who were not flow-limited when semirecumbent: both became flow-limited when supine. We conclude that NEP provides a simple method to detect flow limitation in mechanically ventilated patients. The supine position enhances flow limitation.

[Assessment of perioperative myocardial damage based on circulating heavy chain myosin fragments]. / Valutazione del danno citomiocardico perioperatorio mediante dosaggio dei frammenti circolanti delle catene pesanti di miosina.

To evaluate myocardial damage induced by coronary bypass surgery, to construct a reference data set in postoperative patients and to ascertain the impact of perioperative myocardial infarction on myosin release from sarcolemmal membrane we serially measured levels of serum fragments of myosin heavy chains by means of monoclonal antibody immunoradiometric assay (MYOSIN IRMA ERIA Pasteur). After surgery serum levels of myosin increased from third postoperative day and peaked on seventh day. Peak myosin levels did correlate with enzymatic activities of CPK (r = 0.69; p < 0.001) and of CPK-MB (r = 0.75; p < 0.001). Six patients suffered postoperative myocardial infarction: in these patients myosin levels were significantly different from those without infarctions (3651 +/- 1569 versus 699 +/- 206 ng/ml; p < 0.01). No correlation could be demonstrated between cardiopulmonary bypass time or aortic cross clamp duration. The rise of myosin levels observed in nearly all patients suggests a minor intraoperative damage to the contractile apparatus that sometimes is diagnosed as myocardial infarction and often does not meet clinical diagnostic criteria.

Effects of low flux-low pressure cardiopulmonary bypass on intracellular acid-base and water metabolism.

In eight patients undergoing open heart surgery for elective myocardial revascularization, extra-intracellular acid-base and water metabolism parameters were studied before and after cardiopulmonary bypass procedures. All patients presented a different degree of metabolic acidosis related to plasma lactate increase. Intracellular acid-base indexes did not change significantly, though all but one patient showed an intracellular buffers consumption. Both total muscle and extracellular water increased, while intracellular water did not change. It was concluded that low flux-low pressure perfusion CPB was related to a substantial preservation of cell integrity.

[Water-electrolyte and acid-base changes during extracorporeal circulation]. / Variazioni idroelettrolitiche ed acido-basiche durante circolazione extracorporea.

Changes in fluid, electrolyte and acid-base balance were evaluated in 8 patients during extracorporeal circulation. H2O increase and osmolarity and colloid osmotic pressure decrease, due to priming and perfusion technique used for cardiopulmonary by pass, were found. Mild respiratory alkalosis was also present. K+ serum, because of KCL supplements, was always maintained within the normal values, while Na+ serum concentration was low, despite of large amounts of Na+ infused during perfusion. After examination of disturbances in fluid, electrolyte and acid-base balance, the Authors report the performed corrections and emphasize the importance of a prompt recognition and the immediate therapy of these changes to avert serious cardiac impairments during extracorporeal circulation or during the immediate postoperative period.