Morfina subaracnóidea associada à anestesia geral para revascularização miocárdica: efeitos sobre a função respiratória, a analgesia, o consumo de morfina e seus níveis plasmáticos no pós-operatório / Intrathecal morphine plus general anesthesia in cardiac surgery: effects on pulmonary function, postoperative analgesia, morphine consumption and plasma morphine levels

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

BACKGROUNDS: Few evidence exists on beneficial effects of intrathecal analgesia in lung dysfunction observed in postoperative (PO) of cardiac surgery. The objective of this study was to evaluate the effects of intrathecal morphine on pulmonary function, analgesia, morphine consumption and plasma morphine levels in PO of patients undergoing coronary artery bypass graft surgery (CABG). METHODS: Were studied 42 patients undergoing on-pump CABG randomized (control group, n=22 and morphine group, n=20) to receive general anesthesia with or not 400 g of intrathecal morphine. Anesthesia was standardized and in immediate PO, patients received a patient controlled-analgesia pump, 1 mg bolus of morphine, free demand and dipirone if necessary. Forced vital capacity (CVF), expiratory forced volume in first second (EFV1) and EFV1/FVC ratio were measured using spirometry and arterial blood samples obtained preoperatively, in first and second PO days. Intensity of pain, evaluated using visual numeric scale (0-10), morphine solicitation and consumption and plasma morphine levels were evaluated until 36 hours of PO. Statistical analysis was done with repeated measures analysis of variance and Mann-Whiney test (*p<0.05). RESULTS: Both groups had reduction of FVC in PO (control group=1.45 L and 1.38 L, and morphine group=1.18 L and 1.26 L, respectively in first and second PO (p= 0.06) without differences between them. There were no differences in EFV1 (p=0.085), VEF1/CVF (p=0.68) and PaO2/FiO2 ratio between groups (p=0.08). In morphine group was observed reduction in intensity of pain at rest and profound inspiration but most significatively at cough after 18 hours PO (control group=4.73 and morphine group=1.80, p=0.001), 24 hours (control group=4.41 and morphine group=1.40, p=0.022) and 36 hours (control group=3.09 and morphine group=1.55, p=0.015). Was observed reduction in morphine consumption after 18 hours PO (control group=20.14 mg and morphine group=14.10 mg, p=0.037) and after 24 hours (control group=27.8 mg and morphine group= 13.55, p=0.028). After 24 hours of PO, morphine group has reduced plasma morphine levels (control group=16,41 ng/mL and morphine group=4.08 ng/mL, p=0.029). CONCLUSIONS: Central neuraxial effect of morphine did not reduced postoperative pulmonary dysfunction but promoted better postoperative analgesia, reducing pain scores, venous morphine consumption and lower plasma morphine levels in CABG.

ASSUNTO(S)

cirurgia cardíaca dor pós-operatória morfina general anesthesia cardiac surgery função pulmonar anestesia geral subaracnoid analgesia lung function morphine and postoperative pain analgesia subaracnóidea

ACESSO AO ARTIGO

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