Assessment of photoplethysmographic signals for the determination of splanchnic oxygen saturation in humans

The need for a clinically applicable method of detecting splanchnic hypoxia has led to experimental animal studies which indicated the usefulness of intestinal pulse oximetry. Pulse oximetry relies on detection of photoplethysmographic signals. Before developing a pulse oximeter for the measurement of organ oxygen saturation peri-operatively, we designed a system based on a reflectance photoplethysmographic probe to investigate photoplethysmographic signals from human viscera (bowel, liver, and kidney). Recordings were obtained simultaneously from the abdominal viscera and the finger using identical probes. The probe was held sequentially for up to 2 min on the surface of viscera of 12 patients during routine laparotomy. Measurable splanchnic photoplethysmographic signals were recorded for the first time in humans. There were no statistically significant differences between photoplethysmographic amplitudes from viscera and those from the finger. Our results indicate the feasibility of pulse oximetry for the measurement of visceral oxygenation in humans

Investigation of photoplethysmographic signals and blood oxygen saturation values obtained from human splanchnic organs using a fiber optic sensor

Objective A reliable, continuous method of monitoring splanchnic organ oxygen saturation could allow for the early detection of malperfusion, and may prevent the onset of multiple organ failure. Current monitoring techniques have not been widely accepted in critical care monitoring. As a preliminary to developing a continuous indwelling device, this study evaluates a new handheld fiber optic photoplethysmographic (PPG) sensor for estimating the blood oxygen saturation (SpO2) of splanchnic organs during surgery. Methods A fiber optic splanchnic PPG sensor, instrumentation system and virtual instrument were developed to facilitate PPG and SpO2 measurement from splanchnic organs. Following Local Research Ethics Committee approval, the sensor was evaluated on seventeen ASA 1 and 2 patients undergoing open laparotomy. PPG signals were obtained from the large bowel, small bowel, liver and stomach. Simultaneous PPG signals from the finger were also obtained using an identical fiber optic sensor. Results Good quality PPG signals with high signal-to-noise (SNR) ratios were obtained from all splanchnic sites under investigation. Analysis of the ac and dc amplitudes of the red and infrared PPG signals showed there to be a statistically significant difference between PPG signals obtained from splanchnic organs with those obtained from the finger (using fiber optic sensors). Estimated SpO2 values from the splanchnic organs show good agreement with those obtained from the finger using both a fiber optic sensor and a commercial device. Furthermore, the results of a Bland and Altman analysis indicate that fiber optic splanchnic pulse oximetry, particularly of the bowel, may provide a suitable method for monitoring splanchnic organ perfusion. Conclusion The evaluation of a new fiber optic sensor on anaesthetized patients undergoing laparotomy demonstrated that good quality PPG signals and SpO2 estimates can be obtained from splanchnic organs. Such a sensor may provide a useful tool for the intraoperative assessment of splanchnic perfusion

Cancer Epidemiology, Biomarkers & Prevention

71382-13911

Cancer Epidemiology, Biomarkers & Prevention

8755-7621

Comparação entre as administrações tópica e sistêmica de oxitetraciclina no tratamento de vacas com dermatite digital papilomatosa Efficacy of topical and systemic treatments with oxytetracycline for papillomatous digital dermatitis in cows

Comparou-se a eficiência dos tratamentos tópico e sistêmico com oxitetraciclina em vacas com dermatite digital papilomatosa (DDP) e determinaram-se a presença de resíduos desse antimicrobiano no leite e sua concentração no líquido sinovial e no plasma. Utilizaram-se o tratamento tópico com oxitetraciclina em pó (grupo 1) e o sistêmico de longa ação (grupo 2) em 16 vacas holandesas em lactação, acometidas por DDP. Obtiveram-se amostras de plasma, líquido sinovial e leite nos momentos: M0, antes dos tratamentos; M1, seis horas após o tratamento e em intervalos de 12 horas até M23 (264 horas pós-tratamentos). Avaliaram-se o grau de claudicação, a extensão da lesão e a concentração da oxitetraciclina pela cromatografia líquida de alta eficiência. Nas vacas do grupo 1, ocorreu redução das lesões e da claudicação, quando comparadas com as do grupo 2. Nenhuma das amostras de leite, de líquido sinovial e de plasma nos animais do grupo 1 foi positiva para oxitetraciclina. As amostras de leite dos animais do grupo 2, entre M1 e M23, apresentaram valores acima do limite máximo residual permitido para esse antimicrobiano. O tratamento tópico foi eficiente no tratamento de DDP, sem produzir resíduos no leite ou concentrações no plasma e no líquido sinovial. O tratamento sistêmico foi ineficiente para DDP, resultando em resíduos no leite, durante a avaliação.<br>The efficacy of topical versus systemic treatment with oxytetracycline for papillomatous digital dermatitis (PDD) in dairy cows was compared. Antimicrobial residues in milk and their concentrations in synovial fluid and plasma were analysed. Sixteen lactating Holstein cows with PDD lesions were topically treated with oxytetracycline powder (group 1) or long-acting oxytetracycline (group 2). Plasma, synovial fluid, and milk samples were collected in the following moments: M0 (before treatments); at six hours after treatments (M1), and at 12-hour intervals until 264 hours after treatments (M23). Lameness score and lesion size were evaluated. Analysis of oxytetracycline concentration was performed by high-performance liquid chromatography (HPLC). Cows in group 1 showed reduced lesion size and lameness score when compared to cows in group 2. None of the plasma, synovial fluid, or milk samples collected from cows in group 1 were positive to oxytetracycline. However, violative antimicrobial residues were detected in milk samples collected from cows in group 2, from M1 until M23. Topical application of oxytetracycline powder was an efficient treatment for PDD with no risk of violative antimicrobial residues in milk or increases its concentration in plasma or synovial fluid. The systemic administration of oxytetracycline was inefficient to treat PDD and caused violative residues in milk