![]() El riesgo de sesgo se evaluó con la herramienta QUADAS2. ![]() Variables de interés principales Información general (año, entorno, puntos de corte, método estándar), sensibilidad, especificidad y área bajo curva. Se incluyeron los estudios que evaluaban la precisión de la cVCI con un método estándar para medir el gasto cardíaco como prueba índice. Intervenciones Se realizó una búsqueda en MEDLINE y EMBASE. Pacientes o participantes Pacientes con respiración espontánea con indicación de administración de bolos de líquidos. Ámbito Unidades de cuidados intensivos o servicios de urgencias. Diseño Revisión sistemática de estudios de precisión diagnóstica. Objetivo Sintetizar la evidencia sobre la precisión diagnóstica de la colapsabilidad de la vena cava inferior (cVCI) en la predicción de la respuesta a los líquidos en pacientes que respiran espontáneamente. Conclusions IVCc had moderate accuracy for fluid responsiveness assessment in spontaneously breathing patients and should not be used in isolation for this purpose (AU) Despite moderate accuracy of IVCc (SROC 0.83, 95% CI 0.80≠.86), post-test probability of being fluid responsive based on a 50% pre-test probability led to considerable misclassification. Overall, the studies presented a high risk of bias. Result Eight studies were included with 497 patients. We also calculated positive and negative likelihood ratios and developed a Fagon nomogram. We obtained the pooled sensitivity, specificity and summary ROC curve, with estimated confidence intervals from a bivariate model. Risk of bias was assessed with QUADAS 2 tool. Main variables of interest General information (year, setting, cutoffs, standard method), sensitivity, specificity, and area under the receiving operator characteristics curve (AUROC). We included studies assessing IVCc accuracy for fluid responsiveness assessment with a standard method for cardiac output measure as index test. Interventions A search was conducted in MEDLINE and EMBASE. Patients and participants spontaneously breathing patients with indication for fluid bolus administration. Setting Intensive care units or emergency departments. Design Systematic review of diagnostic accuracy studies. Objective To synthesize the evidence about diagnostic accuracy of inferior vena cava collapsibility (IVCc) in prediction of fluid responsiveness among spontaneously breathing patients. CONCLUSION: Different sample size determination methods based on confidence interval estimation should be selected for single proportions with different parameter settings. ![]() In the setting of ω=0.1 with a very low p (0.01-0.05), failure of iteration occurred with nearly all the methods except for the Clopper-Pearson method. In other settings, the performance of the 7 methods did not differ significantly except for a poor symmetry of the Wald method. RESULTS: For a high accuracy requirement (ω =0.05), the Mid-p method and Clopper Pearson method performed better when the incidence of events was low (P < 0.15). With Monte Carlo simulation, the estimated sample size was used to simulate and compare the width of the confidence interval, the coverage of the confidence interval and the ratio of the noncoverage probability. The sample size was calculated using the search method with different parameter settings (proportion of specified events and half width of the confidence interval ). METHODS: We compared 7 methods, namely Wald, AgrestiCoull add z2, Agresti-Coull add 4, Wilson Score, Clopper-Pearson, Mid-p, and Jefferys, for confidence interval estimation for a single proportion. ![]() OBJECTIVE: To compare different methods for calculating sample size based on confidence interval estimation for a single proportion with different event incidences and precisions.
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