Improving patient waiting time of centralized front office service in a regional hub hospital using the discrete event simulation model.

BACKGROUND: Today, hospital rankings are based not only on basic clinical indicators, but even on quality service indicators such as patient waiting times. Improving these indicators is a very important issue for hospital management, so finding a solution to achieve it in a simple and effective way is one of the greatest goals. OBJECTIVES: The aim of this article is to evaluate the use of a discrete event simulation model to improve healthcare processes and reduce waiting time of patients and hospital costs. METHODS: The case study proposed in this paper is the reorganization of non-clinical front office operation for the patients (i.e. booking of exams, delivering medical reports, etc.) of the Careggi University Hospital of Florence, to optimize the utilization of the human resources and to improve performances of the process. RESULTS: The development and validation of the model was made according to an analysis of real processes and data, pre and post implementation of model outcomes. The new organization shows a decrease of waiting times from an average value of 10 minutes and 37 seconds to 5 minutes and 57 seconds (-44%). CONCLUSIONS: This paper shows that discrete event simulation could be a precise, cost-limited tool to optimize hospital processes and performance.

Custom measurement of retinal nerve fiber layer thickness using STRATUS OCT in normal eyes.

PURPOSE: To evaluate variability of retinal nerve fiber layer (RNFL) thickness measurements in normal eyes and their correlation with optic disc diameter by using two different scan options of the ultimate commercial optical coherence tomography (OCT) unit (STRATUS OCT, Carl Zeiss Meditec, Inc., Dublin, CA). METHODS: In this observational case series and instrument validation study 30 eyes of 30 normal subjects were enrolled. Each eye underwent optic disc vertical diameter measurement by means of both stereoscopic photography and planimetry and OCT; RNFL thickness measurements were performed using OCT. Three repetitions of two series of scans were performed. Each eye was scanned at two different options (RNFL thickness 3.4 and Nerve Head Circle). For each option descriptive statistics, analysis of variance, intraclass correlation coefficients (ICCs), and coefficients of variation (COVs) were calculated. To verify the correlation between the two methods of optic disc diameter assessment and to study the influence of optic disc diameter on RNFL measurement using the two different OCT options, Pearson's correlation coefficients were calculated. RESULTS: Optic disc diameter length ranged from 1.47 to 2.04 mm (mean 1.709 mm, SD +/- 0.147) with stereoscopic photographs, and from 1.47 to 2.02 mm (mean 1.703 mm, SD +/- 0.143) with OCT (Pearson correlation coefficient 0.999, p<0.001). Mean RNFL thickness was 89.29 mm (SD +/- 10.80 mm) using the RNFL thickness 3.4 scanning option and 89.88 mm (SD +/- 1.72 mm) using the Nerve Head Circle protocol (Pearson correlation coefficient 0.065, p=0.734). The intersubject variance is higher using the RNFL thickness 3.4 option than using the NHC protocol (sum of square: 1,014,760 vs. 25,741) (p<0.001); the intrasubject variance is very similar in the two groups (2,372 vs 2,360) (p=NS). The ICC is 99.89% when using the RNFL thickness 3.4 option, 95.62% with the NHC protocol (p=NS). COVs were 12.10% and 1.91% by using RNFL thickness 3.4 and Nerve Head Circle option, respectively. Pearson's correlation coefficient was 0.988 (p<0.001) when comparing optic disc diameter and RNFL thickness by using the RNFL thickness 3.4 option and -0.016 (p=0.932) when comparing optic disc diameter and RNFL thickness by using the Nerve Head Circle option. CONCLUSIONS: These results suggest that both scan options give good RNFL thickness measurement reproducibility; the use of the Nerve Head Circle option leads to less interindividual variability and can minimize the effect of differences in optic disc diameter on RNFL thickness measurements in normal subjects.

Optical coherence tomography and fundus microperimetry imaging of spontaneous closure of traumatic macular hole: a case report.

PURPOSE: To report a case of spontaneous closure of traumatic macular hole in a young patient followed using optical coherence tomography (OCT) and fundus microperimetry. METHODS/RESULTS: In the right eye of a 10-year-old child, a traumatic macular hole was observed to spontaneously resolve 18 weeks after blunt trauma. Initially, visual acuity in the right eye was 20/200 and OCT examination showed a 200 microm-diameter full-thickness macular hole with perifoveal edema. Fundus microperimetry examination showed an evident decrease in retinal sensitivity within the macular hole and in the upper macular region where an area of commotio retinae was clearly visible. During follow-up OCT demonstrated the appearance of a band of tissue linking the inferior edge of the hole to the foveal retinal pigment epithelium and at the bottom of the hole the presence of hyperreflective (glial) material. Eighteen weeks after trauma right eye visual acuity had improved to 20/25, OCT examination showed a restored foveal depression, and fundus microperimetry demonstrated an increase in foveal sensitivity. CONCLUSIONS: Both OCT and fundus microperimetry were useful tools for following the favorable course in a case of spontaneous closure of traumatic macular hole in a young patient. During follow-up OCT examinations were able to demonstrate the course of macular hole closure.

Optical coherence tomography imaging of surgical resolution of bilateral vitreomacular traction syndrome related to incomplete posterior vitreoschisis: a case report.

PURPOSE: To report a case of surgical resolution of bilateral vitreomacular traction syndrome related to incomplete posterior vitreoschisis as documented by optical coherence tomography (Stratus OCT, Carl Zeiss Meditec, Dublin, CA). CASE REPORT: In both eyes of a 72-year-old man with bilateral blurred vision, OCT examination disclosed a relevant increase in mean foveal thickness (right eye = 714 microm; left eye = 757 microm) due to a vitreomacular traction syndrome. At the edges of the most highly elevated area of vitreo-macular traction, OCT scans showed a characteristic splitting of the hyperreflective signal in both eyes, usually identified as posterior vitreous cortex. Both eyes underwent vitrectomy with epiretinal membrane peeling. Postoperative OCT examination showed vitreomacular traction resolution in both eyes with an evident decrease in mean foveal thickness (right eye = 364 microm; left eye = 335 microm). Right visual acuity improved from 20/200 to 20/50; left visual acuity changed from 20/150 to 20/40. CONCLUSIONS: OCT was a useful tool in identifying an unusual case of bilateral vitreomacular traction syndrome linked to incomplete posterior vitreoschisis and following a favorable course after surgical management.

Low level potentiation of the brain stem laryngeal reflex.

Trains of electrical stimuli were applied to the superior laryngeal nerve (SLN) innervating the upper respiratory tract while evoked potentials were recorded from the recurrent nerve (RN) which innervates the intrinsic laryngeal muscles. Responses of this brain stem reflex (central delay 3.5-5.0 msec) were compared to the post-tetanic potentiation (PTP) of the polysynaptic ventral root response (L6-S1) with trains of stimuli applied to the dorsal root of adult cats. Stimulation of the SLN with a train of pulses varying from 10-45/sec evokes an initial depression of the polysynaptic potential from the RN followed by a low but sustained increase in the amplitude of the integrated signal (1.2-1.6x) lasting 45-130 msec and lacking the early maximum amplitude as seen in the PTP of the polysynaptic spinal reflex. Both the early and late components of the superior laryngeal-recurrent nerve reflex (SLN-RN) demonstrate potentiation whereas the shortest latency components of the spinal reflex account for most of the PTP. Systemic administration of strychnine sulfate (dosage: 0.03-0.45 mg/kg) does not alter the normalized PTP of the SLN-RN reflex despite enhancement of both early and late components of the reflex following control stimuli at 1/sec.