Morbid obesity has a profound effect on respiratory mechanics and gas exchange. However, most studies were performed in morbidly obese patients before or after anesthesia. We tested the hypothesis that anesthesia and abdominal opening could modify the elastic and resistive properties of the respiratory system. Eleven morbidly obese and eight normal-weight patients scheduled for gastric binding and cancer treatment, respectively, under laparotomy were studied. Respiratory mechanics, partitioned into its lung and chest wall components, were investigated during surgery by means of the end-inspiratory inflation occlusion method and esophageal balloon at five time points. Static respiratory and lung compliance were markedly reduced in obese patients; on the contrary, static compliance of chest wall presented comparable values in both groups. Obese patients also presented higher resistances of the total respiratory system, lung and chest wall, as well as "additional" lung resistance. Mainly in obese patients, laparotomy provoked a significant increase in lung compliance and decrease in "additional" lung resistance 1 h after the peritoneum was opened, which returned to original values after the peritoneum had been closed (P < 0.005). In obese patients, low respiratory compliance and higher airway resistance were mainly determined by the lung component.

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coronary artery. Both lesions were successfully treated with angioplasty and stent implantation. The patient received antiplatelet therapy for 30 days. Forty-five days after angioplasty, with another normal sestamibi-dipyridamole perfusion imaging, and without any symptoms, the abdominal aortic aneurysm was corrected through retroperitoneal access while the patient was anesthetized with lumbar peridural anesthesia with a catheter combined with general anesthesia. Clamping of the infra-renal aorta lasted 49 minutes, and the surgery lasted 2 hours and 25 minutes. The patient received 3500 mL of crystalloids, 500 mL of hydroxyethyl amide, 150 mL of 20% albumin, and 445 mL of blood retrieved from intraoperative auto-transfusion. The diuresis during surgery was 1000 mL, 800 being in the period after reperfusion. At the beginning of surgery, hemoglobin was 14.3g/dL, and, after surgery, it was 11.4g/dL. The patient was extubated at the end of surgery and remained in the ICU for 20 hours. The postoperative period was uneventful, and the patient was discharged from the hospital 4 days after surgery. Two years after surgery, the patient is in excellent condition, with no cardiovascular symptoms. DiscussionThe incidence of coronary artery disease is significantly greater in patients undergoing vascular surgery than in the general surgical population 1,2 . Myocardial perfusion imaging with sestamibi and dipyridamole has a sensitivity of 96%, when stenoses > 70% are considered, and specificity for detecting disease in the anterior descending coronary artery and in the right coronary artery of 97% and 89%, respectively 3 . The limitations of perfusion imaging are found in patients with hypertension, ventricular hypertrophy and left bundlebranch block. Stress echocardiography is preferred for that subgroup 4 . In addition, other factors, such as caffeine ingestion before the test (inadequate preparation), presence of 3-vessel lesions, and the use of beta-blockers may reduce the sensitivity of myocardial perfusion imaging. Patients who will undergo perfusion imaging with drugs, such as adenosine or dipyridamole, should refrain from having caffeine and medications derived from the xanthines at least in the 24 hours preceding the test. Caffeine and the xanthines block the adenosine receptors, reducing the effect of vasodilation and heart rate elevation. These alterations reduce the sensitivity of the test and increase the chance of false-negative results 5,6 . Patients with 3-vessel lesions or a lesion in the left main coronary artery have a worse prognosis. Nevertheless, in the presence of 3-vessel lesions, perfusion imaging may detect a "balanced" pattern of perfu- In high-risk noncardiac surgeries, such as vascular surgeries, that cause greater cardiac demand, patients with significant coronary artery disease (CAD) should be adequately identified and undergo pharmacological optimization or surgical revascularization. Some studies have tried to define strategies to identify patients at risk for perioperative cardiac events; how...

DESCRITORES:Cirurgia torácica geral. em pacientes com ,ev&scula,izaçl o p,évia. latores de ,isco INTRODUÇÃO A insuliciência coronariana, em seus diversos graus, é ale<:çio importante e causadora de complicações em pacienle cirurgico não cardíaco 3.4 . Diaole deste lato. deve-se decidir pela viabilidade do procedimenlO cirúrgico em questão, ou a melhoria da perluslio miocárdica previamnte à cirurgia. Atuai mente, a maioria dos autores preconiza a revascularização do miocárdio previamente à cirurgia não cardfaca. como forma de estabilizar as condições de perlusão tecidu al. tomando maiores as reservas coronarianas e miocárdicas. oecessári-aS durante e após qualquer procedlmentoclrúrgi-co 2, e, 7 . No eotanto, pouco tem sido discutido quanto ao perfodoapós a revascularização, em que as condições do paciente seriam ideais para um oovo ato cirúrgico 7. Sabe-se que a evolução da doaoçacoronariana não estaciona ap6sa revascularização. Portanto, haveria maior chan.c:e de insuliciên.c:iacoronariana em outros locais, à medida em que decorre o tempo após a ,,:,vascularização e. teoricameote, o prognóstico seria pior em paciente ravasclJlarizado há longo tempo antes da cirurgia atual. Por outro lado. a proximidade da cirurgia não cardlacacomare~ascularizaçliopréviapoderialevar a quadros de instabilidade coroJ'la.iaoa. dovidoa eleitos de adaptação a um regime de débito murto alto e à descompeosação decorrente do eto cirurgrCO.

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