A novel in vitro membrane oxygenator circuit was developed to test gas exchange where particular elements could be examined whilst keeping other variables constant. The circuit comprises two membrane oxygenators connected to form a continuous blood circuit resembling venous and arterial blood conditions. The effects of Isoflurane, a volatile anaesthetic, on oxygen transfer were investigated. RBC resistance to nitric oxide diffusion (DNO) was tested in this circuit by haemolysis and addition of the haemoglobin-based-oxygen-carrier (HBOC) Oxyglobin. The circuit was primed with equine blood flowing at 2.5 l/min. The oxygenator was ventilated with 5 l/min air/oxygen/N2 mix providing a range of FiO2. The deoxygenator received 5 l/min 5% CO2 in N2 with 0.2-0.3 l/min CO2. Isoflurane 1%, NO 4000-16000 ppb and CO 0.03% were added to the oxygenator gas. Uptake of O2, CO2, CO and NO were calculated by gas inlet and outlet concentrations and flow rates. Arterial and venous oxygen dissociation curve (aODC and vODC) comparisons were made. Isoflurane uptake by the circuit blood was evident and 1% Isoflurane did not affect oxygen uptake (p=0.981), aODC or vODC (p=0.311 and p=0.751). Haemolysis did not affect O2 or CO2 transfer but increased DNO (p<0.001). 250ml free Hb solution addition to the circuit increased DNO by 91% (p<0.0001). Addition of 250ml Oxyglobin increased DNO by 143% from 7.41±2.77 to 17.97±1.83 ml/min/mmHg. Oxyglobin caused a right shift of aODC and vODC (p<0.0001) but NO-bound Oxyglobin caused a left vODC shift (p<0.0001). Conclusion: Isoflurane administered via a membrane oxygenator does not affect O2 uptake or carriage in the blood. RBC surroundings provide significant resistance to DNO in circuit tests. Significant uptake of NO by Oxyglobin supports the potential of HBOCs to scavenge endothelial NO in vivo, causing vasoconstriction.

Made available in DSpace on 2016-01-26T12:51:32Z (GMT). No. of bitstreams: 1 renatageronfinoti_dissert.pdf: 2240331 bytes, checksum: e80f129b0db02c473d3a9c4f5162e004 (MD5) Previous issue date: 2011-11-29 / To analyze the security and efficacy of a new membrane oxygenator, the so-called OXM 1500. Methods: From May 2005 to September 2006, six sheep of Santa Inês breed (5 male and 1 female, respectively) were studied. The average body weight was 14.1 (±5) kg, body surface 0.6 (±0.2) m2 and a mean age 3.8 (±1.5) months. All of them were submitted to extracorporeal circulation (CEC) with evaluation at 10, 30, 60, 120, 180 and 240 minutes. The following values were obtained: values of oxygen transference (TTO2) and carbon dioxide transference (TTCO2), haemoglobin (HBS) and free haemoglobin (HBL), the score of platelets and of leucocytes, and heat transference rate. Results: TTO2 and TTCO2 were adequate. Lesion of the majority formed blood elements was insignificant; there no modifications in HBS, HBL levels; platelets and leucocytes decreased over time. Heat exchange was effective (p &#8804; 0.05). Conclusions: The membrane OXM 1500 infant oxygenator, tested in sheep, showed adequate oxygenation capacity, CO2 removal capacity, and small alteration of haemoglobin and platelets without significant decrease of leucocytes, as expected. Heat exchanger connected to the oxygenator was efficient in temperature changes. / Analisar a segurança e a eficácia de um novo oxigenador de membrana denominado OXM -1500. Métodos: No período de maio de 2005 a setembro de 2006, foram estudados seis ovinos da raça Santa Inês, sendo cinco machos e uma fêmea, com peso corpóreo médio de 14,1 (±5) kg, superfície corpórea de 0,6 (±0,2) m2 e idade média de 3,8 (±1,5) meses. Todos foram submetidos à circulação extracorpórea (CEC) com avaliação nos tempos 10, 30, 60, 120, 180 e 240 minutos, obtendo-se os valores de taxa de transferência de oxigênio (TTO2) e de taxa de transferência de gás carbônico (TTCO2), hemoglobina sérica (HBS) e livre (HBL), plaquetometria, leucometria e taxa de transferência de calor. Resultados: Houve adequadas TTO2 e TTCO2. A lesão da maioria dos elementos figurados do sangue foi insignificante, sem alterações dos níveis de HBS, HBL, plaquetas e o número de leucócitos diminuíram com o tempo. A troca de calor foi efetiva (p &#8804; 0,05). Conclusão: O oxigenador de membrana infantil OXM-1500, testado em ovinos, mostrou-se com capacidade adequada de oxigenação, remoção de gás carbônico e pequena alteração da hemoglobina e plaquetas, com diminuição do número de leucócitos de forma esperada. O trocador de calor acoplado ao oxigenador foi eficaz nas variações de temperatura.