RESUMEN
BACKGROUND: Laparoscopic camera navigation (LCN) is vital for the successful performance of laparoscopic operations, yet little time is spent on training. This study aimed to develop an inexpensive LCN simulator, to design a structured curriculum, and to determine the transferability of skills acquired. METHODS: In this study, 0 degrees and 30 degrees LCN simulators were developed for use on a videotrainer platform. Transferability was tested by enrolling 20 medical students in an institutional review board-approved, randomized, controlled, blinded protocol. Subjects viewed a video tutorial and were pretested in LCN on a porcine Nissen model. Procedures were videotaped and the LCN performance was scored by a blinded rater according to the number of standardized verbal cues required and the percentage of time an optimal surgical view (%OSV) was obtained. Procedure time also was recorded. Subjects were stratified and randomized. The trained group practiced on the LCN simulator until competency was demonstrated. The control group received no training. Both groups were posttested on the porcine Nissen model. RESULTS: The constructed simulators required 35 man hours for development, cost $25 per board for materials, and proved to be durable. The trained group demonstrated significant improvement in verbal cues (p = 0.001), %OSV (p < 0.001), and procedure time (p = 0.001), whereas the control group showed improvement only in verbal cues (p < 0.02). At posttesting, the training group demonstrated significantly better scores for verbal cues (2.1 vs 8.0; p = 0.02) and %OSV (64% vs 45% p = 0.01) than the control group. CONCLUSION: These data suggest that the LCN simulator is cost effective and provides trainees with skills that translate to the operating room.
Asunto(s)
Competencia Clínica/economía , Simulación por Computador/economía , Cirugía General/economía , Cirugía General/educación , Laparoscopía/economía , Adulto , Animales , Análisis Costo-Beneficio , Señales (Psicología) , Diseño de Equipo , Femenino , Humanos , Estudios Prospectivos , Método Simple Ciego , Programas Informáticos , Porcinos , Interfaz Usuario-Computador , Grabación en Video/economíaRESUMEN
Milrinone improves function in failing adult hearts, but it has not been examined in the immature myocardium. The purpose of this study was to characterize the effects of milrinone, a phosphodiesterase inhibitor, on immature hearts, and compare these to dobutamine, a commonly used catecholamine inotrope. One hundred isolated working neonatal rabbit hearts were used. Hearts were made ischemic (37 degrees C) for 1 hour and reperfused for 0, 10, 40, or 70 minutes. In separate groups, infusion of milrinone (1.0 microg/mL) or dobutamine (0.1 microg/mL) was begun after reperfusion for 10 or 40 minutes. High energy phosphates, total nondiffusable nucleotides, cyclic adenosine monophosphate (cAMP), and the percent recovery of cardiac output were determined. Cardiac output returned to normal, and adenosine triphosphate (ATP) and total nondiffusable nucleotide levels did not decline when dobutamine or milrinone were begun after 10 minutes of reperfusion. In hearts receiving inotropes after 40 minutes of reperfusion, when high energy phosphates were low, ATP increased, and total nondiffusable nucleotide repletion was observed. Cardiac output did not improve when inotropes were begun after 40 minutes. cAMP was higher in milrinone hearts compared to dobutamine, but there was no simple relation between cAMP and ventricular function. Inotropes may increase purine salvage pathway activity. Deriving maximum benefit from inotropes may depend on beginning infusions early, before the appearance of irreversible changes.
Asunto(s)
Cardiotónicos/farmacología , Corazón/efectos de los fármacos , Isquemia Miocárdica/fisiopatología , Inhibidores de Fosfodiesterasa/farmacología , Piridonas/farmacología , Adenosina Trifosfato/metabolismo , Animales , Animales Recién Nacidos , Gasto Cardíaco/efectos de los fármacos , AMP Cíclico/metabolismo , Dobutamina/farmacología , Milrinona , Isquemia Miocárdica/metabolismo , Reperfusión Miocárdica , Miocardio/metabolismo , Nucleótidos/metabolismo , Purinas/metabolismo , Conejos , Factores de Tiempo , Función Ventricular/efectos de los fármacosRESUMEN
We have observed different ATP interactions in two guanylate cyclase (GC)-coupled natriuretic peptide (NP) receptor subtypes, designated NPR-A and NPR-B. The NPR-A is selectively expressed by LLC-PK1 epithelial cells and the NPR-B by NIH-3T3 fibroblast cells. In LLC-PK1 membranes, ATP-Mg2+ potentiated ANP-stimulated GC activity (ANP-s-GC). In contrast, in NIH-3T3 membranes, ATP-Mg2+ inhibited ANP-s-GC but enhanced CNP-stimulated GC activity (CNP-s GC). ATP in the presence of Mn2+ inhibited LLC-PK1 and NIH-3T3 membrane ANP-s-GC and CNP-s-GC. These are the first data suggesting that the ATP-Mg2+ produces different effects between membrane NPR-A and -B subtypes. We have also demonstrated that GC of NPR-B is sensitive to methylene blue.