The testing of any physiological diagnostic system in-vivo depends critically on the stability of the anesthetized animal used. That is, if the systemic physiological parameters are not tightly controlled, it is exceedingly difficult to assess the precision and accuracy of the system or interpret the consequence of disease. In order to ensure that all measurements taken using the experimental system are not affected by fluctuations in physiological state, the animal must be maintained in a tightly controlled physiologic range. The main goal of this project was to develop a robust monitoring and control system capable of maintaining the physiological parameters of the anesthetized animal in a predetermined range, using the instrumentation already present in the laboratory, and based on the LabVIEWR software interface. A single user interface was developed that allowed for monitoring and control of key physiological parameters including body temperature (BT), mean arterial blood pressure (MAP) and end tidal CO2 (ETCO2). Embedded within this interface was a fuzzy logic based control system designed to mimic the decision making of an anesthetist. The system was tested by manipulating the blood pressure of a group of anesthetized animal subjects using bolus injections of epinephrine and continuous infusions of phenylephrine (a vasoconstrictor) and sodium nitroprusside (a vasodilator). This testing showed that the system was able to significantly reduce the deviation from the set pressure (as measured by the root mean square value) while under control in the hypotension condition (p < 0.10). Though both the short-term and hypertension testing showed no significant improvement, the control system did successfully manipulate the anesthetic percentage in response to changes in MAP. Though currently limited by the control variables being used, this system is an important first step towards a fully automated monitoring and control system and can be used as the basis for further research.

<p><strong>Background: </strong>Myocardial injury after noncardiac surgery (MINS) increases the risk of 30-day mortality. Intraoperative hemodynamic events (i.e., tachycardia, bradycardia, hypotension, and hypertension) may contribute to developing MINS.</p> <p><strong>Objectives: </strong>To determine if the addition of the duration spent within predefined intraoperative systolic blood pressure (BP; mmHg) (i.e.,160-199 and ≥200) and heart rate (HR; bpm) (i.e.,100-140 and >140) hemodynamic bands improved the prediction of Day 1 MINS (i.e., postoperative troponin T elevation ≥0.03 ng/ml within the first day after surgery) beyond preoperative risk model prediction.</p> <p><strong>Methods: </strong> Prospective observational data was used to developed a baseline risk model to predict Day 1 MINS. Preoperative HR, systolic BP, and hemoglobin as well as intraoperative duration spent within each predefined hemodynamic band were explored to identify optimal thresholds for the prediction of Day-1 MINS. Preoperative variables were added to the baseline risk model to create a preoperative model. Intraoperative variables were then added to the preoperative risk model to create the final model. Models were compared using discrimination (c-statistic) and net reclassification index (NRI).</p> <p><strong>Results: </strong>Adding preoperative hemoglobin ≤105 g/dL, systolic BP110 improved baseline model discrimination (0.783 to 0.792, p5min; HR >100 for >147min; systolic BP59min and systolic BP >160 for >42min further improved discrimination (0.8; p</p> <p><strong>Conclusion:</strong> Adding intraoperative hemodynamic durations significantly improved Day-1 MINS model discrimination and risk stratification compared to the baseline risk model.</p> / Master of Health Sciences (MSc)

Anterior cruciate ligament reconstruction utilizing a hamstring autograft is a surgical technique that has gained popularity among orthopedic surgeons caring for adolescent patients. While utilization of a hamstring autograft is a revered technique, harvest of the hamstring yields significant pain. Sciatic peripheral nerve blockade has proven to reliably provide analgesia at the hamstring donor site. Single-injection sciatic peripheral nerve blockade is considered a basic and effective technique, making its use following anterior cruciate ligament reconstruction standard practice in many institutions. The duration of action of a single-injection sciatic peripheral nerve blockade may fail to outlast the pain arising from the hamstring donor site, prompting some clinicians to employ continuous sciatic peripheral nerve blockade via an indwelling catheter. A lack of comparative effectiveness studies exists in the literature regarding the duration of action of peripheral nerve blockade necessary to adequately provide pain control following hamstring autograft harvest, resulting in disagreement among clinicians as to best pain control practices. Proponents of continuous sciatic peripheral nerve blockade assert that while more costly, the extended duration of analgesia afforded by this technique improves pain control postoperatively and decreases the use of other pain medications. Advocates of single-injection sciatic peripheral nerve blockade cite concerns associated with continuous sciatic peripheral nerve blockade known to be detrimental to rehabilitation, such as decreased active knee flexion and increased risk of falls. The purpose of this research is to compare the effect of single-injection sciatic PNB to continuous sciatic PNB on 1) postoperative pain control as measured by self-reported pain scores, pain medication use, and unplanned hospital admission due to poor pain control, 2) active knee flexion, and 3) patient satisfaction with pain control following ACL reconstruction with a hamstring autograft. The findings of this study have the potential to guide informed clinical reasoning and decision making regarding sciatic peripheral nerve blockade techniques following hamstring autograft harvest in adolescents undergoing anterior cruciate ligament reconstruction.

ABSTRACT PREDICTORS OF SITUATION AWARENESS IN GRADUATE STUDENT REGISTERED NURSE ANESTHETISTS Suzanne M. Wright, Ph.D. A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Virginia Commonwealth University. Virginia Commonwealth University, 2009 Major Director: J. James Cotter, Ph.D. Situation awareness (SA) is defined as one’s perception of the elements of the environment, the comprehension of their meaning, and the projection of their status in the near future. Stated more simply, SA is knowing what is going on around you. The concept of SA is well known in the field of aviation which is characterized by complexity and dynamism. The discipline of anesthesia shares these same characteristics, yet the study of SA in this setting is in its infancy. Human error has been implicated in nearly 80% of all preventable medical errors. It is well documented that lack of SA frequently contributes to human error. Although the discipline of anesthesia has led the medical field in patient safety through rigorous study of human error and adverse events in the operating room, crises in anesthesia still exist. Nurse anesthetists should possess the ability to acquire and maintain SA at all times during clinical situations in the operating room, yet there are no studies examining SA in this population. Guided by Endsley’s theory of situation awareness, the purpose of this study was to provide nurse anesthesia educators with a best evidence predictor model of SA in GSRNAs for curricular implementation. The study objectives are to determine: a) the extent to which memory, cognition, and automaticity are related to situation awareness, b) the extent to which any relationship amongst memory, cognition, and automaticity mediates their relationship with situation awareness, and c) the extent to which Endsley’s theory of situation awareness is supported in the GSRNA population. After IRB approval, 71 GSRNAs were randomly selected from each of three universities chosen for this study. A non-experimental, correlational design was used to measure the relationship between memory, cognition, and automaticity and SA. Situation awareness was measured by the WOMBAT-CS, a computer-based assessment tool for evaluating SA in complex-system operators such as pilots, air traffic controllers, and anesthetists. A stepwise multiple regression was performed between the GSRNA attributes and SA scores. Beta-weights were used to identify the magnitude each relationship. Findings from this study revealed that cognition best predicts SA in the population of Graduate Student Registered Nurse Anesthetists, with the addition of memory and automaticity contributing no additional predictive value to the model. The results of this study have the potential to make a positive impact on the education and training of GSRNAs. Additionally, this study may provide foundational support for further research directed at assessing the effectiveness of high-fidelity simulated operating room environments in promoting SA in GSRNAs.

INTRODUCTION: The anesthetic management for pediatric patients undergoing direct laryngoscopy and/or bronchoscopy (DLB) is administered based on the anesthesiologist’s preference. Objectives: The preliminary analysis of this study aims to identify variables that decrease surgical end-to-transport (SET) time and directly impacts patient outcomes. SET time is defined as the time of surgery end to the time of patient exit from the operating room. METHODS: After IRB approval, all DLBs performed at Boston Children’s Hospital (Boston, MA) by the Otolaryngology Department from June 2012 to December 2014 (n= 2419) were obtained from the Anesthesia Information Management System. With a 0.05 level of significance, a multivariate logistic regression was performed in SAS v9.3 with SET time as the dependent variable and surgery duration, age, gender, ASA status, airway device and extubation status as the independent variables. Airway device and extubation status were found to be moderately predictable of each other, so separate models were conducted. Spearman correlation testing was performed to evaluate the relationship between SET time and post-anesthesia care unit (PACU) duration. RESULTS: We excluded cases having ASA classification >2, age >21 years, regional nerve blocks, tracheostomy, nasal cannula, or unknown airway or extubation status. Remaining cases (n = 967) were arranged by SET times and dichotomized by the median value (14 minutes) into two groups (≤14 minutes and >14 minutes). After adjusting for other variables, we found that patients with an endotracheal tube (ETT) were 4.85 times more likely to have a SET time higher than the median, as compared with to those having with a laryngeal mask airway (LMA) (p = 0.0023, 95% CI: 1.76, 13.33). We also found that patients with an ETT were 2.89 times more likely to have a SET time higher than the median compared with those having a mask airway device. (p < 0.0001, 95% CI: 2.09, 3.98). In addition, there was a weak positive correlation between SET time and PACU duration (r = 0.09406, p = 0.0069). DISCUSSION: Preliminary analysis indicates that airway management has a significant impact on SET time after adjusting for surgery duration, age, gender, and ASA status. The use of either a mask or an LMA resulted in a lower SET time than the use of an ETT. The correlation of SET time and PACU duration suggests that reducing SET time does not negatively impact post-operative outcomes and may even be positively, though weakly, correlated. This study is limited by its retrospective nature. Future analysis will include the evaluation of commonly used perioperative anesthetics with dosage and timing variables and their correlation with SET time and patient outcomes.

No description available.

Made available in DSpace on 2014-06-11T19:30:29Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-02-06Bitstream added on 2014-06-13T19:00:39Z : No. of bitstreams: 1 moro_jv_dr_jabo.pdf: 1083668 bytes, checksum: 1de24260fe4cf8ed8b23a56ca988ee52 (MD5) / Avaliaram-se os efeitos de diferentes frações inspiradas de oxigênio (FiO2) e da infusão contínua de tramadol sobre a resposta à hipovolemia aguda. Foram utilizados 48 coelhos adultos distribuídos em seis grupos: grupo tramadol 100% (GT100), 60% (GT60) ou 40% (GT40) e grupo controle 100% (GC100), 60% (GC60) ou 40% (GC40). Os animais foram induzidos (5 V%) e mantidos (2,05 ± 0,18 V%) à anestesia com isofluorano e, após 60 minutos, retiraram-se 12 mL/kg de sangue arterial para induzir a hipovolemia. Dez minutos após, os coelhos receberam bolus de 1 mL de solução de NaCl a 0,9% (GC100, GC60 e GC40) ou 5 mg/kg de tramadol (GT100, GT60 e GT40), seguido de infusão contínua dos mesmos (1 mL/kg/h e 0,025 mg/kg/min, respectivamente). As mensurações dos parâmetros hemogasométricos, hematológicos, respiratórios e cardiovasculares tiveram início 60 minutos após a indução anestésica (M0), dez minutos após a retirada total de sangue e imediatamente antes do bolus de tramadol ou NaCl 0,9% (M10) e em intervalos de 15 minutos (M25, M40, M55 e M70). Para as variáveis hematológicas, também foi colhida uma amostra antes da indução anestésica (MB). Os dados foram submetidos à análise de variância seguida pelo teste de Tukey (p<0,05). As pressões parciais de oxigênio (PaO2) e dióxido de carbono (PaCO2) no sangue arterial, pressão alveolar de oxigênio (PAO2) e diferença alvéolo-arterial de oxigênio [P(A-a)O2] foram maiores para a FiO2 maior. O índice respiratório (IR) e as relações entre PaO2 e PAO2 e entre PaO2 e FiO2 foram maiores no GT40. A pressão arterial média diminuiu após a hipovolemia em todos os grupos, exceto no GT40. A contagem de leucócitos, linfócitos, neutrófilos bastonetes e monócitos decresceu significativamente após a indução anestésica e foram agravadas após a hipovolemia. Para o plaquetograma, quanto maior a FiO2, maior a contagem desses fragmentos coroplasmáticos anucleados / To evaluate different inspired oxygen fractions (FiO2) and continuous infusion of tramadol on the response to acute hypovolemia, 48 adult rabbits were used and divided into six groups: tramadol 100% group (GT100), 60% (GT60) or 40 % (GT40) and control 100% group (GC100), 60% (GC60) or 40% (GC40). Isoflurane was used for induction (5% V) and maintenance of general anesthesia (2.05 ± 0.18 V%) and, after 60 minutes, hypovolemia was induced by removing arterial blood (12 ml/kg). After 10 minutes, the rabbits received a bolus of NaCl 0.9% (GC100, GC60 and GC40) or tramadol (GT100, GT60 and GT40), followed by continuous infusion of the same solution. The measurements of blood gas, hematological, cardiovascular and respiratory parameters were taken 60 minutes after anesthetic induction (M0), ten minutes after hypovolemia induction and immediately before a bolus of tramadol or NaCl 0.9% (M10), and then at 15-minute intervals (M25, M40, M55 and M70). For haematological variables also sample was collected before induction of anesthesia (MB). Numeric data were subjected to analysis of variance followed by Tukey test (p <0.05). The arterial partial pressures of oxygen (PaO2) and of carbon dioxide (PaCO2), alveolar oxygen partial pressure (PAO2) and alveolar-arterial oxygen gradient [P(Aa)O2] showed higher means with the highest FiO2 used. The GT40 showed the lowest respiratory index (RI), the highest oxygen tension ratio (PaO2/PAO2) and arterial oxygen partial pressure/inspired oxygen fraction ratio (PaO2/FiO2). The arterial pressures decreased after hypovolemia in all groups, except in the GT40 for systolic (SAP) and diastolic (DAP) arterial pressure. The leukocyte, lymphocytes, neutrophils and monocytes count decreased significantly after induction of anesthesia and again after hypovolemia. For thrombogram monitoring, with the higher FiO2, the platelet count was greater

Made available in DSpace on 2014-06-11T19:32:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-11-21Bitstream added on 2014-06-13T20:44:21Z : No. of bitstreams: 1 000741072.pdf: 1794954 bytes, checksum: 9eeec84c37efb66a3ec71a70c59dc035 (MD5) / Estudos para desenvolver técnicas mais aperfeiçoadas na abordagem da dor merecem atenção. As nanopartículas são carreadores de fármacos, que podem aumentar sua eficácia terapêutica e diminuir os efeitos adversos. Ao considerar a possível excitação causada pelo uso de opioides por via IV, objetivou-se estudar opções alternativas a esta via para administrar metadona em equinos. seis éguas, de 2 a 4 anos, com peso médio de 354 ± 34 kg receberam com intervalo de sete dias e de forma aleatória 0,5 mg/kg de cloridrato de metadona O, IM e IV e nanopartículas lipídicas sólidas O. O avaliador não ciente do tratamento registrou a pressão arterial sistólica (PAS), a distancia do lábio inferior ao chão, as frequências cardíaca e respiratória, a motilidade intestinal e os limiares nociceptivos térmico, mecânico e elétrico durante 4 horas. Colheu-se sangue durante 6 horas para posterior análise da concentração plasmática de metadona por cromatografia de alta eficiência (CLAE). Avaliaram-se os perfis plasmáticos de metadona por abordagem não compartimental e compartimental. Analisou-se os dados paramétricos por modelos de medidas repetidas para avaliar diferenças entre os tratamentos e momentos. Usou-se o teste de Tukey para ajustar os valores-P resultantes das comparações múltiplas. Para dados não paramétricos, utilizou-se o teste Wilcoxon para comparar os tratamentos em cada momento e o de Bonferroni para ajustar o valor-P resultante das comparações múltiplas (p < 0,05). Em relação ao valor basal, nos animais tratados por via IV, a PAS aumentou por 80 minutos, os movimentos intestinais diminuíram entre 45 e 80 minutos e o limiar nociceptivo mecânico aumentou por 45 minutos. O limiar nociceptivo térmico aumentou em relação ao basal aos 60 e 80 minutos nos grupos IM e IV respectivamente e elétrico aumentou após o valor basal por 140 minutos após metadona IM e de 45 até 240 minutos... / Studies for the development of improved techniques for pain management deserve attention. Nanoparticles are carriers of drugs used to increase therapeutic efficacy and decrease adverse effects. Excitement is usually observed when opioids are administered intravenously. This study aimed to investigate new options, besides the intravenous route, for methadone administration in horses. The antinociceptive effect, physiologic parameters and pharmacokinetics (PK) were evaluated. Six mares (354 ± 34 kg; 2 - 4 years) received 0.5 mg/kg of oral, intramuscular and intravenous methadone or orally methadone nanoparticles formulation prepared in-house, at one week interval. A blinded observer registered non invasive systolic arterial blood pressure (SAP), heart and respiratory rates, distance from the floor to animal’s muzzle, intestinal motility, and mechanical, thermal and electrical nociceptive thresholds for four hours. Blood samples were collected for up to six hours for measurement of plasma methadone concentration. Methadone PK was evaluated by non-compartmental and compartmental modeling. Two way ANOVA followed by Tukey or Wilcoxon test was used to compare differences among groups, followed by Bonferroni correction for multiple comparisons (P < 0.05). Compared to basal values, IV methadone increase SAP for 80 minutes, reduced intestinal motility between 45 and 80 minutes and increased mechanical threshold for 45 minutes. Thermal nociceptive thresholds increased for 60 and 80 minutes after IM and IV methadone and electrical nociceptive thresholds increased for 140 minute after IM methadone and from 45 to 240 minutes after IV methadone. After IV methadone, elimination was rapid (0.92 ± 0.32 L/h/kg for IV), half life was short (0.63 ± 0.11 h for IV) and mean retention time was 0.97 ± .0.17 h. One open compartmental model with first order elimination best described the plasma PK in all groups. Methadone PK profile was of first order ...

Persistent postsurgical pain (PPSP) is reported as recurrent and frequently disabling complication of many surgical procedures. The consequences for PPSP not only reduce the quality of life for patients but also financially tax the health care system, considering the volume of surgical procedures performed annually. Development of chronic pain has been proposed to involve a complex pathophysiology combined with pre-, intra-, and post-operative risk factors. There is no definite recommendation on which factor to assess (in which surgery) and what tools to utilize for conducting a study on PPSP, since many recognized risk factors for PPSP are contradictory. For a comprehensive overview of major PPSP risk factors for identification and possible prevention, we conducted a systematic review and meta-analysis of the published literature on the risk factors across six major surgical groups: breast surgery, chest/thoracic surgery, total hip arthroplasty/total knee arthroplasty (THA/TKA), gynecologic surgery, iliac crest bone harvest (ICBH), and groin hernia repair. Furthermore, to assess the generalizability of the meta-analysis results, we sought to conduct a retrospective, cross-sectional study examining the prevalence and major risk factors of PPSP after cystectomy for bladder cancer. The meta-analysis found that no single risk factor was associated with PPSP across all surgical groups. Age and previous surgery were found to be risk factors for PPSP in gynecologic surgery. For thoracic surgery, male sex and BMI were found as risk factors for PPSP. Surgical duration, presurgical chronic pain, and BMI were risk factors for groin hernia repair. The prevalence of PPSP in our cystectomy study was 22.1%. Female sex and presurgical chronic pain were risk factors significantly associated with PPSP after cystectomy. No risk factors were universally associated with PPSP. Persistent pain after each type of surgical procedure appear to have separate set risk factors among age, BMI, sex, previous surgery, and presurgical pain.

abstract: The medical field is constantly looking for technological solutions to reduce user-error and improve procedures. As a potential solution for healthcare environments, Augmented Reality (AR) has received increasing attention in the past few decades due to advances in computing capabilities, lower cost, and better displays (Sauer, Khamene, Bascle, Vogt, & Rubino, 2002). Augmented Reality, as defined in Ronald Azuma’s initial survey of AR, combines virtual and real-world environments in three dimensions and in real-time (Azuma, 1997). Because visualization displays used in AR are related to human physiologic and cognitive constraints, any new system must improve on previous methods and be consistently aligned with human abilities in mind (Drascic & Milgram, 1996; Kruijff, Swan, & Feiner, 2010; Ziv, Wolpe, Small, & Glick, 2006). Based on promising findings from aviation and driving (Liu & Wen, 2004; Sojourner & Antin, 1990; Ververs & Wickens, 1998), this study identifies whether the spatial proximity affordance provided by a head-mounted display or alternative heads up display might benefit to attentional performance in a simulated routine medical task. Additionally, the present study explores how tasks of varying relatedness may relate to attentional performance differences when these tasks are presented at different spatial distances. / Dissertation/Thesis / Masters Thesis Engineering 2017