Computed tomography assessment of lung structure in patients undergoing cardiac surgery with cardiopulmonary bypass

Hypoxemia is a frequent complication after coronary artery bypass graft (CABG) with cardiopulmonary bypass (CPB), usually attributed to atelectasis. Using computed tomography (CT), we investigated postoperative pulmonary alterations and their impact on blood oxygenation. Eighteen non-hypoxemic patients (15 men and 3 women) with normal cardiac function scheduled for CABG under CPB were studied. Hemodynamic measurements and blood samples were obtained before surgery, after intubation, after CPB, at admission to the intensive care unit, and 12, 24, and 48 h after surgery. Pre- and postoperative volumetric thoracic CT scans were acquired under apnea conditions after a spontaneous expiration. Data were analyzed by the paired Student t-test and one-way repeated measures analysis of variance. Mean age was 63 ± 9 years. The PaO2/FiO2 ratio was significantly reduced after anesthesia induction, reaching its nadir after CPB and partially improving 12 h after surgery. Compared to preoperative CT, there was a 31 percent postoperative reduction in pulmonary gas volume (P < 0.001) while tissue volume increased by 19 percent (P < 0.001). Non-aerated lung increased by 253 ± 97 g (P < 0.001), from 3 to 27 percent, after surgery and poorly aerated lung by 72 ± 68 g (P < 0.001), from 24 to 27 percent, while normally aerated lung was reduced by 147 ± 119 g (P < 0.001), from 72 to 46 percent. No correlations (Pearson) were observed between PaO2/FiO2 ratio or shunt fraction at 24 h postoperatively and postoperative lung alterations. The data show that lung structure is profoundly modified after CABG with CPB. Taken together, multiple changes occurring in the lungs contribute to postoperative hypoxemia rather than atelectasis alone.

Efeito analgesico do fentanil administrado no espaco peridural de pacientes politraumatizados. / Analgesic effect of fentanyl injection in the epidural space in patients with multiple trauma

Foi estudada a acao analgesica do fentanil adminsitrado no espaco peridural de 18 pacientes politraumatizados. A puncao foi feita em L2 - L3 introduzindo-se um cateter por 3 cm em direcao cefalica, mantendo-se todos os pacientes decubito dorsal, em aclive de 45o. por trinta minutos, apos cada dose; receberam a 1 a 6 doses de acordo com as necessidades.Foram analisados a frequencia do pulso, a pressao arterial, a frequencia ventilatoria, os limites da faixa da dor (superior e inferior) e a duracao de analgesia.O resultado mais importante foi a diminuicao da faixa da dor, o que contribuiu para um melhor comportamento dos pacientes frente a fisioterapia ventilatoria