Browsing by Author "Nunes, Catarina S."
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- Airway approach for caesarean section under general anaesthesia: a national surveyPublication . Pombo, A.; Cardoso, T. M.; Araújo, A. M.; Frada, R.; Nunes, Catarina S.; Órfão, J.; Lemos, P.
- An application of Box-Jenkins methodology to model the series of currency in circulation in MozambiquePublication . Arone, Samuel G.; Nunes, Catarina S.; Grilo, Luís M.
- Anaesthesia - related fears - a cross - sectional survey among the portuguese populationPublication . Pereira, C.; Fernandes, D. Sobreira; Mota, A. Carmezim; Gonçalves, G.; Pinho, S.; Araújo, M.; Pereira, F.; Saraiva, A.; Paiva, M.; Nunes, Catarina S.; Cavaleiro, C.; Machado, Humberto S.Introduction: Patients experience preoperative anxiety. The objective of this study was to assess patients’ fears concerning anaesthesia and evaluate possible associations with sociodemographic background and previous anaesthesia. Methods: A survey was filled preoperatively, for 6 months, including anaesthesia-related fears, sociodemographic data, previous anaesthesia and surgery, current surgical and anaesthetic procedure, and preferred anaesthesia technique. Descriptive statistics, principal component analysis, Chi-square test, t-test and ANOVA were used for statistical analysis. Results: 153 questionnaires were collected. The mean age was 58 years, 61.4% were female and 59.5% employed. 47.1% had an anaesthesia consultation before. 49.7% were ASA II. 78.4% had been submitted to surgery before, 81.7% to anaesthesia and 14.5% had regional anaesthesia. In 73.5% general anaesthesia preferred. Half of patients with previous regional anaesthesia favoured this technique. The most relevant fears were “being paralysed because of anaesthesia”, “not waking up” and “waking up during surgery”. The least relevant were “fasting incapacity”, “having nightmares” and “speaking of personal matters”. A statistically significant relation was observed between the fear of “feeling pain after surgery” and having a previous anaesthetic experience. Female and unemployed patients were more concerned with general complications, while male patients gave more importance to awareness and paralysis. Conclusion: Paralysis after anaesthesia, intraoperative awareness and death were the main concerns of our inquiries.
- Anaesthesia synchronization software: target controlled infusion system evaluationPublication . Bressan, Nadja; Moreira, A. Paulo; Amorim, Pedro; Nunes, Catarina S.Target Controlled Infusion (TCI) systems are based in drug Pharmacokinetic (Pk) and Pharmacodynamic (Pd) models implemented in an algorithm to drive an infusion device. Several studies had compare manual titration of anesthesia and TCI system use; some studies evaluate the performance of the control algorithms for TCI systems, and a considerable number of studies assess the performance of Pk/Pd models implemented into TCI systems. This study presents a set of tests to validate the performance of a TCI system as a computer-aided. The goal of the current study was to assess the performance of the TCI system, Anaesthesia Synchronization Software (ASYS), on clinical set up to evaluate communication consistence (computer - infusion device) and controller performance in real time. These measures provided quantitative and qualitative evidences of software robustness and accuracy to be used at clinical environment.
- Analgesic interpatient variability of remifentanil assessed through pupillary dilation reflexPublication . Vide, Sérgio; Correia, Rui P.; Nunes, Catarina S.; Amorim, Pedro
- Application of Benford’s Law to the Tourism Demand: the case of the Island of Sal, Cape VerdePublication . Neves, Gilberto A.; Nunes, Catarina S.; Fernandes, Paula OdeteThis article presents Benford’s Law applied for the first time to the tourism context, focusing on tourism demand. This law states that in sets of random numbers of natural events, the probability of the first digit of these numbers being 1 is approximately 30%, of being 2 is 18%, and so on until reaching 9 with 4.6% probability. In this context, the objective is to verify if Benford’s Law applies to the monthly numbers of overnight stays registered in the accommodation establishments of the Island of Sal, in the period between 2000 and 2018, to test the data reliability. This research focus on data provided by the National Statistics Institute of Cape Verde. The Chi-Square test (χ2) was used to assess the discrepancy between the observed and expected relative frequencies. The results show that the observed χ2 value is higher than the χ2 critical value (5% significance level), meaning that the number of monthly overnight stays recorded in accommodation establishments on the Island of Sal does not follow Benford’s Law. However, certain possible data disturbances must be considered, such as the occurrence of specific events during that time period. Other factors that could influence the results are the size of the data set and a sub notification in the data collection process. These circumstances may be the cause of the non-adaptation of the number of overnight stays to Benford’s Law. The implication of this fact on the estimation of tourism demand is crucial for the development and optimization of prediction models.
- ARX modeling of drug effects on brain signals during general anesthesiaPublication . Nunes, Catarina S.; Lobo, Francisco A.; Amorim, PedroThe effect of drugs’ interaction on the brain signal Bispectral Index (BIS) of the EEG, is of great importance for an anesthesia control drug infusion system. In this study, the objective was to investigate if an autoregressive with exogenous inputs model (ARX) could be a suitable approach to predicting BIS according to the anesthetic drugs concentrations. Data were collected in 45 neurosurgeries with total intravenous anesthesia every 5s. A stochastic ARX model was fitted to the data of each patient. The models structure that performed better as predictor used a 30s lag for BIS, 1min lag for propofol and 2min lag for remifentanil. The models had a good performance with statistical zero errors (P < 0.05) in 31 patients. The average of absolute errors was 8.2 ± 2.5, showing that the model captures the brain signal trend. This model proved to be effective in modeling and one step prediction of the BIS signal capturing unique characteristics. The results show that the previous brain response trend has influence on the present value, in addition the drugs concentrations from the previous 2min still have influence. This is an important conclusion for the development of drug infusion controller algorithms.
- Assessment of the opioid effect on the pupillary pain indexPublication . Vide, Sérgio; Correia, Rui P.; Amorim, Pedro; Nunes, Catarina S.
- Automation in anesthesia: computer controlled propofol infusion and data acquisitionPublication . Bressan, Nadja; Castro, Ana; Braga, Carlos; Lages, Jose; Silva, Nuno R.; Portela, Paulo; Miranda, Pedro; Oliveira, Sergio; Mendes, Joaquim; Amorim, Pedro; Nunes, Catarina S.This work presents the improvement of a software for a clinical setup, the Anesthesia Synchronization Software (ASYS). The first version presented the data acquisition from cerebral monitors and a partial control with Target Controlled Infusion (TCI) system. Based on pharmacokinetic models, the effect-site and plasma concentrations can be related with the drug dose infused and vice versa. This later version comes with the implementation of the hemodynamic monitor always present in operating rooms and with the full TCI system developed to determine the infusion rates of the drug which are given as commands to the infusion pumps.
- Avaliação digital na matemática: exames onlinePublication . Nunes, Catarina S.