Loading...
155 results
Search Results
Now showing 1 - 10 of 155
- Mode of delivery and labour analgesia: a study of preference in portuguese pregnant womenPublication . Costa, Inês Coelho da; Nunes, Catarina S.; Machado, Humberto S.Background: Portugal has had one of the highest cesarean rates in Europe, possibly influenced by patient preferences. A reduction in the prevalence of these rates due to safety, quality, and concern with costs is one of the current goals of obstetric care. Fear of pain, often associated with vaginal delivery, is one of the reasons why pregnant women might prefer a cesarean section. Objective: The aim of this study was to identify the type of delivery and anaesthesia/analgesia preferred, as well as the reasons and factors associated with this preference, in a representative sample in order to identify possible modifiable factors possibly involved in increased rates. Methods: A descriptive cross-sectional study was carried out by an anonymous questionnaire to 245 pregnant women from February to April 2018. Respondents were also asked about their preference for peripartum anaesthesia/analgesia and on the sources of information that helped decide their preferences. Results: 22% of respondents would prefer an elective cesarean section. This preference was higher in women with a previous cesarean section. The preference for vaginal delivery was higher in women with more advanced pregnancies. The main reasons that led participants to prefer a vaginal delivery were the quicker postpartum recovery and not wanting to miss the first hours of their child's life. Regarding the preference for an elective cesarean section, the main reasons were fear and convenience. Most pregnant women preferred epidural analgesia. Respondents who selected their doctor (most common source) were more likely to prefer vaginal delivery. Conclusion: A minority of women showed a preference for cesarean delivery. A majority would prefer to have epidural anaesthesia. Despite the high cesarean rates, maternal desire for cesarean section is low, suggesting that this number is due to factors other than the preference of pregnant women.
- Effect of propofol and remifentanil on a somatosensory evoked potential indicator of pain perception intensity in volunteersPublication . Castro, Ana; Amorim, Pedro; Nunes, Catarina S.; Almeida, Fernando Gomes deSomatosensory evoked potentials (SEPs) have been linked to noxious activation and stimulus intensity. In this exploratory study we investigated the impact of anaesthetic drugs on SEPs and pain ratings, to assess their applicability as an objective measure of the nociception/anti-nociception balance. Following institutional approval and written informed consent, 10 healthy adult volunteers were enrolled (29.5 ± 9.1 years, 63.0 ± 8.9 kg and 171.4 ± 7.2). Median nerve electrical stimulation was adjusted according to volunteers' sensitive, motor and painful thresholds (PT). Baseline SEPs were registered, and remifentanil and propofol administered using a stair scheme TCI. For each drug combination a 1.3×PT stimulus was administered, and volunteers evaluated pain intensity in a numerical rating scale (0-10). SEPs' amplitudes and latencies were normalized by the baseline values, reducing volunteers' intervariability. Stimulation currents varied between 6-52 mA (1.3×PT) and pain ratings between 0 and 9. Cortical SEPs latencies were decreased for higher stimulus intensities (P < 0.01), accompanied by increased pain ratings (P < 0.01). An individually adjusted/normalized ratio based on cortical SEPs amplitude and interpeak latency is proposed([Formula: see text]): [Formula: see text] and NSR were significantly correlated in three out of nine subjects, and [Formula: see text] and remifentanil Ce were significantly correlated in two (low number of evaluation points). [Formula: see text] was shown to decrease with increasing doses of propofol and remifentanil (P < 0.05). The proposed metric was depressed by anaesthetics and reflected pain evaluations. Further research is necessary to increase the number of volunteers and drugs' combination, to assess its applicability during surgically adequate anesthetic leves.
- Elementos de Estatística Multivariada. Atividades Formativas (exercícios e resoluções)Publication . Nunes, Catarina S.
- A novel multivariate STeady-state index during general ANesthesia (STAN)Publication . Castro, Ana; Almeida, Fernando Gomes de; Amorim, Pedro; Nunes, Catarina S.The assessment of the adequacy of general anesthesia for surgery, namely the nociception/anti-nociception balance, has received wide attention from the scientific community. Monitoring systems based on the frontal EEG/EMG, or autonomic state reactions (e.g. heart rate and blood pressure) have been developed aiming to objectively assess this balance. In this study a new multivariate indicator of patients' steady-state during anesthesia (STAN) is proposed, based on wavelet analysis of signals linked to noxious activation. A clinical protocol was designed to analyze precise noxious stimuli (laryngoscopy/intubation, tetanic, and incision), under three different analgesic doses; patients were randomized to receive either remifentanil 2.0, 3.0 or 4.0 ng/ml. ECG, PPG, BP, BIS, EMG and [Formula: see text] were continuously recorded. ECG, PPG and BP were processed to extract beat-to-beat information, and [Formula: see text] curve used to estimate the respiration rate. A combined steady-state index based on wavelet analysis of these variables, was applied and compared between the three study groups and stimuli (Wilcoxon signed ranks, Kruskal-Wallis and Mann-Whitney tests). Following institutional approval and signing the informed consent thirty four patients were enrolled in this study (3 excluded due to signal loss during data collection). The BIS index of the EEG, frontal EMG, heart rate, BP, and PPG wave amplitude changed in response to different noxious stimuli. Laryngoscopy/intubation was the stimulus with the more pronounced response [Formula: see text]. These variables were used in the construction of the combined index STAN; STAN responded adequately to noxious stimuli, with a more pronounced response to laryngoscopy/intubation (18.5-43.1 %, [Formula: see text]), and the attenuation provided by the analgesic, detecting steady-state periods in the different physiological signals analyzed (approximately 50 % of the total study time). A new multivariate approach for the assessment of the patient steady-state during general anesthesia was developed. The proposed wavelet based multivariate index responds adequately to different noxious stimuli, and attenuation provided by the analgesic in a dose-dependent manner for each stimulus analyzed in this study.
- Online group consultation on labor analgesia for pregnant women: is it feasible?Publication . Tomás, Ana Sofia; Dias, Raquel M.; Cabido, Hermínia; Nunes, Catarina S.; Lemos, PauloIntroduction: Our department of anesthesiology has been conducting weekly, for several years, a group consultation to educate childbearing people about labor analgesia. The emergence of the COVID-19 pandemic forced an adaptation to a virtual consultation format. Since there are no studies about online group consultation on labor analgesia in order to understand its role, an anonymous questionnaire was created and applied. The objective was to evaluate this new consultation format, namely the ease of access, usefulness of the content provided, and its impact on the satisfaction and experience of childbirth. Materials and methods: An observational prospective study was conducted. A questionnaire was sent by email after childbirth to all childbearing people participating in the online consultation from January 20, 2021, to March 2, 2022. SPSS Statistics version 28.0 (IBM Corp. Released 2021. IBM SPSS Statistics for Windows, Version 28.0. Armonk, NY: IBM Corp) was used for statistical analysis. Internal consistency was analyzed using Cronbach’s alpha. Results: A total of 563 participants were eligible, and 404 (71.8%) completed questionnaires were analyzed. A few technical problems were reported. The participants considered their privacy respected, and more than 90% were satisfied with the content of the online consultation, the opportunity to pose questions, and the help managing expectations. Considering face-to-face consultation, 89.6% of patients considered the online format an effective alternative, 63.2% believed it could replace the old model, and 96.3% would recommend it. Conclusions: Our study demonstrates that online consultation on labor analgesia was a good strategy during the COVID-19 pandemic and has the potential to be used in this format in the future.
- Increased lung inflammation with oxygen supplementation in tracheotomized spontaneously breathing rabbits: an experimental prospective randomized studyPublication . Machado, Humberto S.; Nunes, Catarina S.; Sá, Paula; Couceiro, António; Silva, Álvaro Moreira da; Águas, ArturBackground Mechanical ventilation is a well–known trigger for lung inflammation. Research focuses on tidal volume reduction to prevent ventilator-induced lung injury. Mechanical ventilation is usually applied with higher than physiological oxygen fractions. The purpose of this study was to investigate the after effect of oxygen supplementation during a spontaneous ventilation set up, in order to avoid the inflammatory response linked to mechanical ventilation. Methods A prospective randomised study using New Zealand rabbits in a university research laboratory was carried out. Rabbits (n = 20) were randomly assigned to 4 groups (n = 5 each group). Groups 1 and 2 were submitted to 0.5 L/min oxygen supplementation, for 20 or 75 minutes, respectively; groups 3 and 4 were left at room air for 20 or 75 minutes. Ketamine/xylazine was administered for induction and maintenance of anaesthesia. Lungs were obtained for histological examination in light microscopy. Results All animals survived the complete experiment. Procedure duration did not influence the degree of inflammatory response. The hyperoxic environment was confirmed by blood gas analyses in animals that were subjected to oxygen supplementation, and was accompanied with lower mean respiratory rates. The non-oxygen supplemented group had lower mean oxygen arterial partial pressures and higher mean respiratory rates during the procedure. All animals showed some inflammatory lung response. However, rabbits submitted to oxygen supplementation showed significant more lung inflammation (Odds ratio = 16), characterized by more infiltrates and with higher cell counts; the acute inflammatory response cells was mainly constituted by eosinophils and neutrophils, with a relative proportion of 80 to 20% respectively. This cellular observation in lung tissue did not correlate with a similar increase in peripheral blood analysis. Conclusions Oxygen supplementation in spontaneous breathing is associated with an increased inflammatory response when compared to breathing normal room air. This inflammatory response was mainly constituted with polymorphonuclear cells (eosinophils and neutrophils). As confirmed in all animals by peripheral blood analyses, the eosinophilic inflammatory response was a local organ event.
- Remifentanil analgesic interpatient variability assessed through pupillary reflex dilationPublication . Vide, Sérgio; Nunes, Catarina S.; Correia, Rui P.; Teixeira, J.; Antunes, P.; Rego, J.; Amorim, Pedro
- Feedforward adaptive control of the Bispectral Index of the EEG using the intravenous anaesthetic drug propofolPublication . Nunes, Catarina S.; Mendonça, Teresa; Lemos, João M.; Amorim, PedroThe problem of controlling the level of unconsciousness measured by the Bispectral Index (BIS) of the EEG of patients under anaesthesia is considered. The manipulated variable is the infusion rate of the hypnotic drug propofol. In order to tackle the high uncertainties present in the system, the predictive adaptive controller MUSMAR is used. The performance of the controller is illustrated by means of simulations with 50 patient individual adjusted models (nonlinear models), which incorporate the effect of the drugs interaction on BIS. This work presents a feasibility study of the control of the BIS exploring the above ideas. These results show that such a control structure can be adequate to control the BIS signal during total intravenous anaesthesia. The controller was able to adequately achieve and maintain the BIS signal with different patient dynamics, reference values and noise. A major challenge for the automation of anaesthesia consists of replicating the experience of the anaesthetist. Clearly, this calls for the use of feedforward from measurable signals correlated with disturbances (e.g. electromyography—EMG, analgesic drug). The results also show that the analgesic and EMG have different influences on the performance and therefore carry different but relevant information.
- Estatística Aplicada às Ciências do Consumo. Tema 3: Testes de hipóteses não paramétricosPublication . Nunes, Catarina S.
- 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.